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Sample records for difusion elastica antiproton-proton

  1. Antiproton-proton annihilation into collinear charged pions and kaons

    SciTech Connect

    Ahmad, S.; Amsler, C.; Armenteros, R.; Auld, E.; Axen, D.; Bailey, D.; Barlag, S.; Beer, G.; Bizot, J.h.; Botlo, M.; and others

    1986-10-15

    AN analysis is presented of two body final states of collinear charged pions or kaons from antiproton-proton annihilation at rest in the ASTERIX spectrometer at LEAR. The relative branching ratio of kaons to pions, which is sensitive to the dynamics of quark-antiquark annihilation and rearrangement, is shown to differ for P and S wave initial states.

  2. Multiplicity Distributions from Antiproton-Proton Collisions at 1.8 Tev Center of Mass Energy

    NASA Astrophysics Data System (ADS)

    Wang, Chi-Ho.

    Charged-particle multiplicity distributions from antiproton-proton collisions at 1800 GeV center of mass energy, obtained with the E735 detector multiplicity hodoscope, are presented and discussed. A simple iteration method is used for conversion from number of observed hodoscope hits to true charged-particle multiplicity. The first four moments of the distribution are compared with distributions from lower energies. The distributions are also fit to KNO-G and negative binomial functions.

  3. Elastica as a dynamical system

    NASA Astrophysics Data System (ADS)

    Bates, Larry; Chhabra, Robin; Śniatycki, Jędrzej

    2016-12-01

    The elastica is a curve in R3 that is stationary under variations of the integral of the square of the curvature. Elastica is viewed as a dynamical system that arises from the second order calculus of variations, and its quantization is discussed.

  4. Antiproton-proton annihilation into light neutral meson pairs within an effective meson theory

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Bystritskiy, Yury M.; Ahmadov, Azad I.; Tomasi-Gustafsson, Egle

    2017-08-01

    Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in s , t , and u channels, is applied here to π0π0 production. Form factors with logarithmic s and t (u ) dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for π0η and η η production in the same energy range. A good agreement is generally obtained with all existing data.

  5. Antiproton-proton annihilation into charged light meson pairs within effective meson theory

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Bystritskiy, Yury M.; Tomasi-Gustafsson, Egle

    2017-04-01

    We revisit antiproton-proton annihilation into light mesons in the energy domain relevant to the antiproton annihilation at Darmstadt (PANDA) experiment at the GSI Facility for Antiproton and Ion Research (FAIR) [2.25 (1.5 ) ≤√{s }(pL) ≤5.47 (15 ) GeV (GeV /c ) where √{s }(pL) is the total energy (the beam momentum in the laboratory frame)]. An effective meson model is developed, with mesonic and baryonic degrees of freedom. Form factors are added to take into account the composite nature of the interacting hadrons. A comparison is made with the existing data for charged pion pair production and predictions for angular distributions and energy dependence in the range 3.362 (5 ) ≤√{s }(pL) ≤4.559 (10.1 ) GeV (GeV /c ). The model is applied to π±p elastic scattering, using crossing symmetry, and to charged kaon pair production, on the basis of SU(3) symmetry. In all cases the results illustrate a nice agreement with the data.

  6. An assessment of the antiproton-proton option for the SSC

    SciTech Connect

    1986-05-01

    The Conceptual Design Report (CDR) for the Superconducting Super Collider (SSC) describes a proton-proton collider with an energy of 20 TeV per beam and a maximum luminosity of 10{sup 33}cm{sup {minus}2}s{sup {minus}1} per collision point. This directly responds to the recommendation made by the High Energy Physics Advisory Panel to the US Department of Energy and the National Science Foundation in July 1983. That recommendation called for the ``immediate initiation of a multi-TeV high-luminosity proton-proton collider project with the goal of physics experiments at this facility at the earliest Possible date.`` The primary Parameters of the SSC in the Conceptual Design Report have been chosen taking account of both the physics discovery reach of the machine and accelerator physics considerations. The endeavor of the study reported here was to compare the feasibility of an antiproton-proton collider with the proton-proton collider presented in the SSC Conceptual Design Report. The rapid advances in the technology of p{bar p} colliders at CERN and Fermilab suggest that p{bar p} might be a viable alternative to a PP collider (or might be a first stage of an eventual p{bar p} collider). There is Potentially a large cost saving from eliminating one 20 TeV ring of magnets since the protons and antiprotons share the same ring. Following this suggestion, workshops at the University of Chicago and at Snowmass have provided a forum for these ideas. These reports formed the starting point for our study.

  7. A recoil detector for the measurement of antiproton-proton elastic scattering at angles close to 90°

    NASA Astrophysics Data System (ADS)

    Hu, Q.; Bechstedt, U.; Gillitzer, A.; Grzonka, D.; Khoukaz, A.; Klehr, F.; Lehrach, A.; Prasuhn, D.; Ritman, J.; Sefzick, T.; Stockmanns, T.; Täschner, A.; Wuestner, P.; Xu, H.

    2014-10-01

    The design and construction of a recoil detector for the measurement of recoil protons of antiproton-proton elastic scattering at scattering angles close to are described. The performance of the recoil detector has been tested in the laboratory with radioactive sources and at COSY with proton beams by measuring proton-proton elastic scattering. The results of laboratory tests and commissioning with beam are presented. Excellent energy resolution and proper working performance of the recoil detector validate the conceptual design of the KOALA experiment at HESR to provide the cross section data needed to achieve a precise luminosity determination at the PANDA experiment.

  8. Properties of compressible elastica from relativistic analogy.

    PubMed

    Oshri, Oz; Diamant, Haim

    2016-01-21

    Kirchhoff's kinetic analogy relates the deformation of an incompressible elastic rod to the classical dynamics of rigid body rotation. We extend the analogy to compressible filaments and find that the extension is similar to the introduction of relativistic effects into the dynamical system. The extended analogy reveals a surprising symmetry in the deformations of compressible elastica. In addition, we use known results for the buckling of compressible elastica to derive the explicit solution for the motion of a relativistic nonlinear pendulum. We discuss cases where the extended Kirchhoff analogy may be useful for the study of other soft matter systems.

  9. Study of the CHI(1) and CHI(2) States Produced in Antiproton-Proton Annihilations in Fermilab Experiment 760

    NASA Astrophysics Data System (ADS)

    Marques, Jose Laurencio

    A study of the chi_1(^3P _1) and the chi_2(^3P _2) states of charmonium formed in anti-proton -proton annihilations is reported in this dissertation. Performed at Fermi National Accelerator Laboratory, Experiment 760 used an internal molecular hydrogen jet target and circulating beam of momentum cooled antiprotons to conduct energy scans of the two resonances. The small momentum spread of the antiproton beam allowed very precise measurements of both the resonance mass and total width to be made. From a sample of 483 chi_1 and 556 chi_2 events the following resonance parameters have been determined: Gamma_{chi1} = (0.86 +/- 0.14) MeV, Gamma _{chi2} = (2.01 +/- 0.18) MeV, M_{chi1 } = (3510.51 +/- 0.13) MeV/c^2, M_{ chi2} = (3556.03 +/- 0.14) MeV/c^2, Gamma( chi_1to|{p}p)times BR(chi_1to J/psigamma)times BR(J/psito e^+e^-) = (1.22 +/- 0.15) eV, and Gamma( chi_2to|{p}p)times BR(chi_2to J/psigamma)times BR(J/psito e^+e^-) = (1.68 +/- 0.16) eV. The angular distribution for the reaction chi_{1,2}to J/psi+gamma to e^+e^-+gamma was also studied. For the chi_1 resonance, from a sample of 360 events, the radiative decay quadupole amplitude has been found to be a_2 = -0.14 +/- 0.06. For the chi_2, from a sample of 1904 events, the radiative decay quadrupole and octupole amplitudes have been found to be a_2 = -0.15 +/- 0.07 and a_3 = 0.00 +/- 0.05 respectively. The contribution from helicity zero in the formation process of the chi_2 has also been measured, B_sp{0 }{2} = 0.02_sp{ -0.02}{+0.13}..

  10. Localized buckling of a floating elastica.

    PubMed

    Audoly, B

    2011-07-01

    We study the buckling of a two-dimensional elastica floating on a bath of dense fluid, subjected to axial compression. The sinusoidal pattern predicted by the analysis of linear stability is shown to become localized above the buckling threshold. A nonlinear amplitude equation is derived for the envelope of the pattern. These results provide a simple interpretation to the wrinkle-to-fold transition reported by Pocivavsek et al. [Science 320, 912 (2008)]. An analogy with the classical problem of the localized buckling of a strut on a nonlinear elastic foundation is presented.

  11. Tangent Bundle Elastica and Computer Vision.

    PubMed

    Ben-Shahar, Ohad; Ben-Yosef, Guy

    2015-01-01

    Visual curve completion, an early visual process that completes the occluded parts between observed boundary fragments (a.k.a. inducers), is a major problem in perceptual organization and a critical step toward higher level visual tasks in both biological and machine vision. Most computational contributions to solving this problem suggest desired perceptual properties that the completed contour should satisfy in the image plane, and then seek the mathematical curves that provide them. Alternatively, few studies (including by the authors) have suggested to frame the problem not in the image plane but rather in the unit tangent bundleR (2) × S(1), the space that abstracts the primary visual cortex, where curve completion allegedly occurs. Combining both schools, here we propose and develop a biologically plausible theory of elastica in the tangent bundle that provides not only perceptually superior completion results but also a rigorous computational prediction that inducer curvatures greatly affects the shape of the completed curve, as indeed indicated by human perception.

  12. From the elastica compass to the elastica catapult: an essay on the mechanics of soft robot arm

    PubMed Central

    Armanini, C.; Dal Corso, F.; Misseroni, D.

    2017-01-01

    An elastic rod is clamped at one end and has a dead load attached to the other (free) end. The rod is then slowly rotated using the clamp. When the load is smaller than the buckling value, the rod describes a continuous set of quasi-static forms and its end traces a (smooth, convex and simple) closed curve, which would be a circle if the rod were rigid. The closed curve is analytically determined through the integration of the Euler’s elastica, so that for sufficiently small loads the mechanical system behaves as an ‘elastica compass’. For loads higher than that of buckling, the elastica reaches a configuration from which a snap-back instability occurs, realizing a sort of ‘elastica catapult’. The whole quasi-static evolution leading to the critical configuration for snapping is calculated through the elastica and the subsequent dynamic motion simulated using two numerical procedures, one ad hoc developed and another based on a finite-element scheme. The theoretical results are then validated on a specially designed and built apparatus. An obvious application of the present model would be in the development of soft robotic limbs, but the results are also of interest for the optimization analysis in pole vaulting. PMID:28293144

  13. From the elastica compass to the elastica catapult: an essay on the mechanics of soft robot arm

    NASA Astrophysics Data System (ADS)

    Armanini, C.; Dal Corso, F.; Misseroni, D.; Bigoni, D.

    2017-02-01

    An elastic rod is clamped at one end and has a dead load attached to the other (free) end. The rod is then slowly rotated using the clamp. When the load is smaller than the buckling value, the rod describes a continuous set of quasi-static forms and its end traces a (smooth, convex and simple) closed curve, which would be a circle if the rod were rigid. The closed curve is analytically determined through the integration of the Euler's elastica, so that for sufficiently small loads the mechanical system behaves as an `elastica compass'. For loads higher than that of buckling, the elastica reaches a configuration from which a snap-back instability occurs, realizing a sort of `elastica catapult'. The whole quasi-static evolution leading to the critical configuration for snapping is calculated through the elastica and the subsequent dynamic motion simulated using two numerical procedures, one ad hoc developed and another based on a finite-element scheme. The theoretical results are then validated on a specially designed and built apparatus. An obvious application of the present model would be in the development of soft robotic limbs, but the results are also of interest for the optimization analysis in pole vaulting.

  14. Balance de carbono en un bosque novedoso de Castilla elastica: resultados preliminares

    Treesearch

    Ariel E. Lugo; Jessica Fonseca da Silva; Alejandra María. Sáez Uribe

    2008-01-01

    During June 17 and 18, 2008, a Castilla elastica forest located in El Tallonal, municipality of Arecibo, functioned as a carbon sink. The net photosynthetic rate ranged from 14.28 (native species) and 21.96 (C. elastica) g C m-1 day-1 and respiration of leaves, stems, and soil varied from 13.76 (native species) and 16.88 (C. elastica) g C m-1 day-1. The net...

  15. Flexive and Propulsive Dynamics of Elastica at Low Reynolds Numbers

    NASA Astrophysics Data System (ADS)

    Wiggins, Chris; Goldstein, Raymond

    1997-11-01

    A stiff one-armed swimmer in glycerine goes nowhere. However, if its arm is elastic, exerting a restorative torque proportional to local curvature, the swimmer can go on its way. Considering this happy consequence, we study a hyperdiffusion equation for the shape of the elastica in viscous flow, find solutions for impulsive or oscillatory forcing, and elucidate relevant aspects of propulsion. We illustrate an experiment which, coupled with this analysis, provides verification of the hyperdiffusive nature of elastohydrodynamics as well as a novel technique for measuring biopolymer bending moduli. Extensions necessary to study the viscous dynamics of twist and writhe are elucidated.

  16. Magnesium affects rubber biosynthesis and particle stability in Ficus elastica, Hevea brasiliensis and Parthenium argentatum

    USDA-ARS?s Scientific Manuscript database

    Natural rubber biosynthesis occurs in laticifers of Ficus elastica and Hevea brasiliensis, and in parenchyma cells of Parthenium argentatum. Natural rubber is synthesized by rubber transferase using allylic pyrophosphates as initiators, isopentenyl pyrophosphate as monomeric substrate and magnesium ...

  17. Development of quality standards of medicinal mistletoe - Helicanthes elastica (Desr.) Danser employing Pharmacopoeial procedures.

    PubMed

    Sunil Kumar, K N; Ravishankar, B; Yashovarma, B; Rajakrishnan, R; Thomas, J

    2016-11-01

    Helicanthes elastica (Desr.) Danser (Loranthaceae), commonly known as Indian mango mistletoe, is a parasitic shrub found widely growing on mango trees in southern India. Development of monographic quality standards is need of the hour for Pharmacopoeial/extra-Pharmacopoeial and folk medicinal plants. Systematic pharmacognostical evaluation of leaves of H. elastica has been carried out employing Pharmacopoeial procedures of testing herbal drugs. Macro-microscopic features of H. elastica leaf were recorded. Ethanolic extract was tested positive for alkaloids, steroids, carbohydrates, tannins, saponins and phenols. HPTLC fingerprint profile was developed for the identification of extracts using reference standard β-sitosterol glucoside. Results of the present investigation would serve as a source of pharmacognostical information and a document to control the quality of H. elastica (Desr.) Danser.

  18. 3-D spatial chaos in the elastica and the spinning top: Kirchhoff analogy.

    PubMed

    Davies, M. A.; Moon, F. C.

    1993-01-01

    The existence of spatially chaotic deformations in an elastica and the analogous motions of a free spinning rigid body, an extension of the problem originally examined by Kirchhoff are investigated. It is shown that a spatially periodic variation in cross sectional area of the elastica results in spatially complex deformation patterns. The governing equations for the elastica were numerically integrated and Poincare maps were created for a number of different initial conditions. In addition, three dimensional computer images of the twisted elastica were generated to illustrate periodic, quasiperiodic, and stochastic deformation patterns in space. These pictures clearly show the existence of spatially chaotic deformations with stunning complexity. This finding is relevant to a wide variety of fields in which coiled structures are important, from the modeling of DNA chains to video and audio tape dynamics to the design of deployable space structures.

  19. Measurement of the resonance parameters of the chi(1)(1**3P(1)) and chi(2)(1**3P(2)) states of charmonium formed in antiproton-proton annihilations

    SciTech Connect

    Andreotti, M.; Bagnasco, S.; Baldini, W.; Bettoni, D.; Borreani, G.; Buzzo, A.; Calabrese, R.; Cester, R.; Cibinetto, G.; Dalpiaz, P.; Garzoglio, G.; Gollwitzer, K.E.; Graham, M.; Hu, M.; Joffe, D.; Kasper, J.; Lasio, G.; Lo Vetere, M.; Luppi, E.; Macri, M.; Mandelkern, M.; /Fermilab /INFN, Ferrara /Ferrara U. /INFN, Genoa /Genoa U. /UC, Irvine /Northwestern U. /INFN, Turin /Turin U. /Minnesota U.

    2005-03-01

    The authors have studied the {sup 3}P{sub J} ({chi}{sub e}) states of charmonium in formation by antiproton-proton annihilations in experiment E835 at the Fermilab Antiproton Source. The authors report new measurements of the mass, width, and B({chi}{sub cJ} {yields} {bar p}p) x {Lambda}({chi}{sub eJ} {yields} J/{psi} + anything) for the {chi}{sub c1} and {chi}{sub c2} by means of the inclusive reaction {bar p}p {yields} {chi}{sub cJ} {yields} J/{psi} + anything {yields} (e{sup +}e{sup -}) + anything. Using the subsample of events where {chi}{sub cJ} {yields} {gamma} + J/{psi} {yields} {gamma} + (e{sup +}e{sup -}) is fully reconstructed, we derive B({chi}{sub cJ} {yields} {bar p}p) x {Lambda}({chi}{sub cJ} {yields} J/{psi} + {gamma}). They summarize the results of the E760 (updated) and E835 measurements of mass, width and B({chi}{sub cJ} {yields} {bar p}p){Lambda}({chi}{sub cJ} {yields} J/{psi} + {gamma}) (J = 0,1,2) and discuss the significance of these measurements.

  20. Partial Localization, Lipid Bilayers, and the Elastica Functional

    NASA Astrophysics Data System (ADS)

    Peletier, Mark A.; Röger, Matthias

    2009-09-01

    Partial localization is the phenomenon of self-aggregation of mass into highdensity structures that are thin in one direction and extended in the others. We give a detailed study of an energy functional that arises in a simplified model for lipid bilayer membranes. We demonstrate that this functional, defined on a class of two-dimensional spatial mass densities, exhibits partial localization and displays the “solid-like” behaviour of cell membranes. Specifically, we show that density fields of moderate energy are partially localized, that is, resemble thin structures. Deviation from a specific uniform thickness, creation of “ends,” and the bending of such structures all carry an energy penalty, of different orders in terms of the thickness of the structure. These findings are made precise in a Gamma-convergence result. We prove that a rescaled version of the energy functional converges in the zero-thickness limit to a functional that is defined on a class of planar curves. Finiteness of the limit enforces both optimal thickness and non-fracture; if these conditions are met, then the limit value is given by the classical elastica (bending) energy of the curve.

  1. Ficus elastica-The Indian rubber tree-an underutilized promising multi-use species

    USDA-ARS?s Scientific Manuscript database

    Ficus elastica known as the Indian rubber tree has a white, milky latex that is a source of natural rubber was analyzed for its phytochemicals as an intermediate energy source. The tree produces a high quantity of protein and oil (24.5 and 6.1% respectively). The polyphenol content was 4.2%, and hyd...

  2. A unified account of tilt illusions, association fields, and contour detection based on elastica.

    PubMed

    Keemink, Sander W; van Rossum, Mark C W

    2016-09-01

    As expressed in the Gestalt law of good continuation, human perception tends to associate stimuli that form smooth continuations. Contextual modulation in primary visual cortex, in the form of association fields, is believed to play an important role in this process. Yet a unified and principled account of the good continuation law on the neural level is lacking. In this study we introduce a population model of primary visual cortex. Its contextual interactions depend on the elastica curvature energy of the smoothest contour connecting oriented bars. As expected, this model leads to association fields consistent with data. However, in addition the model displays tilt-illusions for stimulus configurations with grating and single bars that closely match psychophysics. Furthermore, the model explains not only pop-out of contours amid a variety of backgrounds, but also pop-out of single targets amid a uniform background. We thus propose that elastica is a unifying principle of the visual cortical network.

  3. Initiator-independent and initiator-dependent rubber biosynthesis in Ficus elastica.

    PubMed

    Espy, Stephanie C; Keasling, Jay D; Castillón, Javier; Cornish, Katrina

    2006-04-15

    The rubber-producing tree, Ficus elastica (the Indian rubber tree), requires the same substrates for rubber production as other rubber-producing plants, such as Hevea brasiliensis (the Brazilian or Para rubber tree), the major source of commercial natural rubber in the world, and Parthenium argentatum (guayule), a widely studied alternative for natural rubber production currently under commercial development. Rubber biosynthesis can be studied, in vitro, using purified, enzymatically active rubber particles, an initiator such as FPP, IPP as the source of monomer, and a metal cofactor such as Mg2+. However, unlike H. brasiliensis and P. argentatum, we show that enzymatically active rubber particles purified from F. elastica are able to synthesize rubber, in vitro, in the absence of added initiator. In this paper, we characterize, for the first time, the kinetic differences between initiator-dependent rubber biosynthesis, and initiator-independent rubber biosynthesis, and the effect of cofactor concentration on both of these processes.

  4. Dynamics of novel forests of Castilla elastica in Puerto Rico: from species to ecosystems

    PubMed Central

    Fonseca da Silva, Jéssica

    2015-01-01

    Novel forests (NFs)—forests that contain a combination of introduced and native species—are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual species in those forests. This study focuses on the functional attributes of Castilla elastica NFs in Puerto Rico and on the differences between introduced and native species growing side by side in these forests. Rates of processes measured here were later compared with data from literature about NSFs. I hypothesize that juvenile plants of C. elastica in NFs have higher survival rate than those of native species and that C. elastica trees have faster biomass fluxes than native trees. To test the hypotheses, I measured survival rates of juvenile plants and tree growth and characterized the aboveground litter fluxes and storage. Although juvenile plants of native species displayed higher survival rates than those of C. elastica (53% vs. 28%), the latter was dominant in the understory (96%). Stand biomass growth rate was 2.0 ± 0.4 (average ± one standard deviation) Mg·ha−1·year−1 for the whole forest, and Guarea guidonia, a native species, exhibited the highest tree growth. Total litter fall was 9.6 ± 0.5 Mg·ha−1·year−1, and mean litter standing stock was 4.4 ± 0.1 Mg·ha−1. Castilla elastica litter fall decomposed twice as fast as that of native species (5.8 ± 1.1 vs. 3.03 ± 1 k·year−1). Literature comparisons show that the present NFs differ in some rates of processes from NSFs. This study brings unique and detailed supporting data about the ecological dynamics under mature novel forest stands. Further comprehensive studies about NFs are important to strengthen the body of knowledge about the wide range of variation of emerging tropical ecosystems. Due to

  5. Extended theory of elastica for free torsional, longitudinal, and radial breathing vibrations of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Delfani, M. R.

    2017-09-01

    Single-walled carbon nanotube (SWCNT) can be viewed as a two-dimensional elastica obtained from rolling up graphene into a cylinder. By extending the formulation of elastica to dynamic problems, the present study provides an analysis for free torsional, longitudinal, and radial breathing vibrations of SWCNTs. With incorporating the effects of both geometrical and material nonlinearities, the exact closed-form expressions are obtained for the deformation field and the natural angular frequency of the elastica corresponding to the freely vibrating SWCNT. It is shown that torsional, longitudinal, and radial breathing modes of deformation are coupled to each other in free vibration of SWCNTs. However, for the special cases of zigzag and armchair SWCNTs as well as the limiting case of large-radius SWCNTs, torsional mode of deformation is decoupled from the other two modes.

  6. Visualization of micromorphology of leaf epicuticular waxes of the rubber tree Ficus elastica by electron microscopy.

    PubMed

    Kim, Ki Woo

    2008-10-01

    Ultrastructural aspects of leaf epicuticular waxes were investigated in Ficus elastica by scanning and transmission electron microscopy. Glossy leaves of the rubber tree were collected and subjected to different regimes of specimen preparation for surface observations. F. elastica leaves were hypostomatic and stomata were surrounded with a cuticular thickening that formed a rim. The most prominent epicuticular wax structures of F. elastica leaves included granules and platelets. Without fixation and metal coating, epicuticular wax structures could be discerned on the leaf surface by low-vacuum (ca. 7 Pa) scanning electron microscopy. In terms of delineation and retention of the structures, the combination of vapor fixation by glutaraldehyde and osmium tetroxide with subsequent gold coating provided the most satisfactory results, as evidenced by high resolution and sharp protrusions of epicuticular waxes. However, erosion of epicuticular wax edges was noted in the immersion fixed leaves, showing less elongated platelets, less distinct wax edges, and granule cracking. These results suggest that the vapor fixation procedure for demonstrating three-dimensional epicuticular wax structures would facilitate characterization of diverse types of waxes. Instances were noted where epicuticular waxes grew over neighboring epidermal ridges and occluded stomata. In cross sections, epicuticular waxes were observed above the cuticle proper and ranged approximately from 100 nm to 500 nm in thickness. The native leaf epicuticular waxes had many layers of different electron density that were oriented parallel to each other and parallel or perpendicular to the cuticle surface, implying strata of crystal growth. Such retention of native epicuticular wax structures could be achieved through the use of acrylic resin treated with less harsh dehydrants and mild heat polymerization, alleviating wax extraction during specimen preparations.

  7. Molecular fingerprinting of Helicanthus elastica (Desr.) Danser growing on five different hosts by RAPD

    PubMed Central

    Sunil Kumar, K.N.; Maruthi, K.R.; Alfarhan, A.H.; Rajakrishnan, R.; Thomas, J.

    2015-01-01

    Mistletoes are hemiparasitic plants growing on aerial parts of other host trees. Many of the mistletoes are reported to be medicinally important. The hemiparasitic nature of these plants makes their chemical composition dependent on the host on which it grows. They are shown to exhibit morphological dissimilarities also when growing on different hosts. Helicanthus elastica (Desr.) Danser (mango mistletoe) is one such less explored medicinal mistletoe found on almost every mango tree in India. Traditionally, the leaves of this plant are used for checking abortion and for removing stones in the kidney and urinary bladder while significant antioxidant and antimicrobial properties are also attributed to this species of mistletoe. The current study was undertaken to evaluate molecular differences in the genomic DNA of the plant while growing on five different host trees using four random markers employing random amplified polymorphic DNA (RAPD) followed by similarity matrix by Jaccard’s coefficient and distance matrix by hierarchal clustering analysis. Similarity and distance matrix data employing just 4 random markers, separately and the pooled data as well, revealed significant difference in the genomic DNA of H. elastica growing on five different hosts. Pooled data of similarity from all the 4 primers cumulatively showed similarity between 0.256 and 0.311. Distance matrix ranged from of 0.256 to 0.281 on pooling the data from all the four primers. The result employing a minimum number of primers could conclude that genomic DNA of H. elastica differs depending upon the host on which it grows, hence the host must be considered while studying or utilizing this mistletoe for medicinal purposes. PMID:27081357

  8. Antimicrobial Potential of Helicanthus elastica (Desr.) Danser - A less explored Indian mistletoe Growing on Mango Trees

    PubMed Central

    Sunil Kumar, Koppala Narayana; Saraswathy, Ariyamuthu; Amerjothy, Swaminathan; Ravishankar, Basaviah

    2014-01-01

    Helicanthus elastica (Desr.) Danser (Loranthaceae) is a less-known medicinally important mistletoe species occurring in India. It is used to check abortion, and also in vesical calculi and kidney affections. There are no detailed studies reporting the antimicrobial potential of this plant. Based on the traditional use and the rich phenolic composition of the whole plant, the antimicrobial property of the alcohol extract was analyzed and the results are outlined in the present paper. For the analysis, zone of inhibition, and minimum inhibitory concentration were used, and the total activity was assayed by standard methodologies. The antimicrobial activity was studied against bacteria like Aeromonas hydrophila, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, Vibrio fischeri, and a fungus Candida albicans. Of the eight tested bacteria, the alcoholic extract of H. elastica was found to be active against K. pneumoniae, A. hydrophila, E. coli, and V. fischeri at concentration ranging from 250 to 500 μg/ml. C. albicans showed inhibition only at a concentration of 2000 μg/ml. PMID:25379468

  9. Extensional Elastica in large deformation as $Gamma $ Γ -limit of a discrete 1D mechanical system

    NASA Astrophysics Data System (ADS)

    Alibert, Jean-Jacques; Della Corte, Alessandro; Giorgio, Ivan; Battista, Antonio

    2017-04-01

    The present paper deals with the rigorous homogenization of a discrete system consisting of extensible rods linked by rotational springs. Specifically, a Γ -convergence result is proven for a sequence of discrete measure functionals En, describing the energy of the discrete system, toward the continuous energy functional for the extensible Euler beam model ( Elastica) in large deformation regime. A relative compactness result for the sequence En is also proven. Moreover, numerical results are shown on the deformed shape and on the total energy of the system when the number of elements of the discrete system increases. The numerical convergence of the energy to a definite value is shown in two cases. The results provide rigorous justification of a very commonly used algorithm for the discretization of the extensible Euler beam, namely Hencky-type beam model.

  10. Densidad de artrópodos activos en la superficie del suelo de un bosque novedoso de Castilla elastica

    Treesearch

    Maria Rivera; Ariel E. Lugo; Shalom V. Vázquez

    2008-01-01

    During the month of June 2008 we collected arthropods active on the surface of the ground in a forest of Castilla elastica located in the northern karst’s Tallonal Reserve in Arecibo, Puerto Rico. In each of 4 plots of 10 m x 10 m we placed three randomly distributed pitfall traps. The traps, which allowed the passage of organisms smaller than 5 mm wide, remained on...

  11. Potential effect of the medicinal plants Calotropis procera, Ficus elastica and Zingiber officinale against Schistosoma mansoni in mice.

    PubMed

    Seif el-Din, Sayed H; El-Lakkany, Naglaa M; Mohamed, Mona A; Hamed, Manal M; Sterner, Olov; Botros, Sanaa S

    2014-02-01

    Calotropis procera (Ait.) R. Br. (Asclepiadaceae), Ficus elastica Roxb. (Moraceae) and Zingiber officinale Roscoe (Zingiberaceae) have been traditionally used to treat many diseases. The antischistosomal activity of these plant extracts was evaluated against Schistosoma mansoni. Male mice exposed to 80 ± 10 cercariae per mouse were divided into two batches. The first was divided into five groups: (I) infected untreated, while groups from (II-V) were treated orally (500 mg/kg for three consecutive days) by aqueous stem latex and flowers of C. procera, latex of F. elastica and ether extract of Z. officinale, respectively. The second batch was divided into four comparable groups (except Z. officinale-treated group) similarly treated as the first batch in addition to the antacid ranitidine (30 mg/kg) 1 h before extract administration. Safety, worm recovery, tissues egg load and oogram pattern were assessed. Calotropis procera latex and flower extracts are toxic (50-70% mortality) even in a small dose (250 mg/kg) before washing off their toxic rubber. Zingiber officinale extract insignificantly decrease (7.26%) S. mansoni worms. When toxic rubber was washed off and ranitidine was used, C. procera (stem latex and flowers) and F. elastica extracts revealed significant S. mansoni worm reductions by 45.31, 53.7 and 16.71%, respectively. Moreover, C. procera extracts produced significant reductions in tissue egg load (∼34-38.5%) and positively affected oogram pattern. The present study may be useful to supplement information with regard to C. procera and F. elastica antischistosomal activity and provide a basis for further experimental trials.

  12. Fluid-driven fracturing of adhered elastica: evolution of the vapour tip

    NASA Astrophysics Data System (ADS)

    Ball, Thomasina V.; Neufeld, Jerome A.

    2016-11-01

    The transient spreading of a viscous fluid beneath an elastic sheet is controlled by the dynamics at the tip. The large negative pressures needed to drive the viscous fluid into the narrowing gap necessitates a vapour tip separating the fluid front and the crack tip. Adhesion of the elastic sheet imposes a curvature at the tip giving rise to an elasto-capillary length scale and the possibility of a balance between elastic deformation and the strength of adhesion. Two dynamical regimes are therefore possible; viscosity dominant spreading controlled by the pressure in the vapour tip and adhesion dominant spreading controlled by interfacial adhesion. A series of constant flux experiments using clear PDMS elastic sheets allow for direct measurement of the vapour tip in the bending (thick sheet) limit. For small fluid fluxes, the experimental results can be explained by a constant interior pressure and a viscous boundary layer near the fluid front and result in an asymptotic model for the advance of adhesion and viscosity dominated fracture fronts resolving the vapour tip. Understanding the fluid-driven fracturing of adhered elastica provides insight into the spreading of shallow magmatic intrusions in the Earth's crust, and the fluid-driven fracturing of elastic media more generally.

  13. The Stochastic Elastica and Excluded-Volume Perturbations of DNA Conformational Ensembles

    PubMed Central

    Chirikjian, Gregory S.

    2010-01-01

    A coordinate-free Lie-group formulation for generating ensembles of DNA conformations in solution is presented. In this formulation, stochastic differential equations define sample paths on the Euclidean motion group. The ensemble of these paths exhibits the same behavior as solutions of the Fokker-Planck equation for the stochastically forced elastica. Longer chains for which the effects of excluded volume become important are handled by piecing together shorter chains and modeling their interactions. It is assumed that the final chain lengths of interest are long enough for excluded volume effects to become important, but not so long that the semi-flexible nature of the chain is lost. The effect of excluded volume is then taken into account by grouping short self-avoiding conformations into ‘bundles’ with common end constraints and computing average interaction effects between bundles. The accuracy of this approximation is shown to be good when using a numerically generated ensemble of self-avoiding sample paths as the baseline for comparison. PMID:20228889

  14. The History of the Planar Elastica: Insights into Mechanics and Scientific Method

    NASA Astrophysics Data System (ADS)

    Goss, Victor Geoffrey Alan

    2009-08-01

    Euler’s formula for the buckling of an elastic column is widely used in engineering design. However, only a handful of engineers will be familiar with Euler’s classic paper De Curvis Elasticis in which the formula is derived. In addition to the Euler Buckling Formula, De Curvis Elasticis classifies all the bent configurations of elastic rod—a landmark in the development of a rational theory of continuum mechanics. As a historical case study, Euler’s work on elastic rods offers an insight into some important concepts which underlie mechanics. It sheds light on the search for unifying principles of mechanics and the role of analysis. The connection between results obtained from theory and those obtained from experiments on rods, highlights two different approaches to scientific discovery, which can be traced back to Bacon, Descartes and Galileo. The bent rod also has an analogy in dynamics, with a pendulum, which highlights the crucial distinctions between initial value and boundary value problems and between linear and nonlinear differential equations. In addition to benefiting from the overview which a historical study provides, the particular problem of the elastica offers students of science and engineering a clear elucidation of the connection between mathematics and real-world engineering, issues which still have relevance today.

  15. The presence of cutan limits the interpretation of cuticular chemistry and structure: Ficus elastica leaf as an example.

    PubMed

    Guzmán-Delgado, Paula; Graça, José; Cabral, Vanessa; Gil, Luis; Fernández, Victoria

    2016-06-01

    Plant cuticles have been traditionally classified on the basis of their ultrastructure, with certain chemical composition assumptions. However, the nature of the plant cuticle may be misinterpreted in the prevailing model, which was established more than 150 years ago. Using the adaxial leaf cuticle of Ficus elastica, a study was conducted with the aim of analyzing cuticular ultrastructure, chemical composition and the potential relationship between structure and chemistry. Gradual chemical extractions and diverse analytical and microscopic techniques were performed on isolated leaf cuticles of two different stages of development (i.e. young and mature leaves). Evidence for the presence of cutan in F. elastica leaf cuticles has been gained after chemical treatments and tissue analysis by infrared spectroscopy and electron microscopy. Significant calcium, boron and silicon concentrations were also measured in the cuticle of this species. Such mineral elements which are often found in plant cell walls may play a structural role and their presence in isolated cuticles further supports the interpretation of the cuticle as the most external region of the epidermal cell wall. The complex and heterogeneous nature of the cuticle, and constraints associated with current analytical procedures may limit the chance for establishing a relationship between cuticle chemical composition and structure also in relation to organ ontogeny. © 2016 Scandinavian Plant Physiology Society.

  16. Total Phenol Content and In Vitro Antioxidant Potential of Helicanthus elastica (Desr.) Danser-A Less-explored Indian Mango Mistletoe

    PubMed Central

    Sunil Kumar, Koppala Narayana; Saraswathy, Ariyamuthu; Amerjothy, Swaminathan; Susan, Thomas; Ravishankar, Basaviah

    2014-01-01

    Natural products are an important source of antioxidant molecules like tannins, phenolic compounds, flavonoids, etc., Helicanthus elastica (Desr.) Danser (Loranthaceae) is one such plant belonging to the category of mistletoe, and grows commonly on the mango trees in India. In the present study, an attempt has been made to assess the antioxidant properties of the plant. Ethanol extract of H. elastica growing on mango tree was studied using different in vitro models. Shade-dried whole plant material was extracted with ethanol by cold percolation. Fifty milligrams of the alcohol extract of H. elastica was weighed and dissolved in 10 ml of methanol. The resultant 5 mg/ml solution was suitably diluted to obtain different concentrations. Total phenol content, reducing power assay, and scavenging of free radicals like nitric oxide, hydroxyl, hydrogen peroxide, and 1,1-diphenyl-2-picrylhydrazyl were studied by standardized in vitro chemical methods using ascorbic acid as the standard. The total phenol content of the plant was found to be 1.89% w/w. The extract showed good reducing power as well as scavenging of free radicals (nitric oxide, hydroxyl, superoxide anion, and hydrogen peroxide) at concentrations ranging from 5 to 100 μg/ml. The study revealed the antioxidant potential of H. elastica. PMID:25379473

  17. Estructura y química del suelo en un bosque de Castilla elastica en el carso del norte de Puerto Rico: resultados de una calicata

    Treesearch

    Christian A. Viera Martinez; Oscar Abelleira; Ariel E. Lugo

    2008-01-01

    We dug a soil pit of 1m x 1m x 1m in a forest dominated by Castilla elastica, a tree for shade coffee introduced in the karst of northern Puerto Rico. We found four soil horizons (designation notes in parenthesis) (A) organic soil matter (E) mineral soil leachate (B) aerobic mineral soil, and (C) saturated soil. The total storage of soil organic matter was 143 Mg/ha....

  18. The characterization of ficaprenol-10, -11 and 12 from the leaves of Ficus elastica (decorative rubber plant).

    PubMed

    Stone, K J; Wellburn, A R; Hemming, F W; Pennock, J F

    1967-01-01

    Evidence from mass, nuclear-magnetic-resonance and infrared spectrometry and from gas-liquid and thin-layer chromatography is presented in favour of the presence of cis-trans-decaprenol, -undecaprenol and -dodecaprenol in the mixture of polyprenols (2.6mg./g.) isolated from leaf tissue of Ficus elastica. The trivial names ficaprenol-10, -11 and -12 are proposed. Nuclear-magnetic-resonance studies showed that each of these prenols contains three trans internal isoprene residues and a cis ;OH-terminal' isoprene residue. Ficaprenol-11 is the major component of the mixture. Chromatographic evidence suggests the presence also of small amounts of ficaprenol-9 and -13. The precise position of the three trans internal isoprene residues was not determined but it is suggested that these are adjacent to the omega-terminal isoprene residue and that the ficaprenols are formed from all-trans-geranylgeranyl pyrophosphate. It is also suggested that ficaprenol-10, -11, -12 and -13 are probably the same compounds as castaprenol-10, -11, -12 and -13.

  19. An elastica arm scale

    PubMed Central

    Bosi, F.; Misseroni, D.; Dal Corso, F.; Bigoni, D.

    2014-01-01

    The concept of a ‘deformable arm scale’ (completely different from a traditional rigid arm balance) is theoretically introduced and experimentally validated. The idea is not intuitive, but is the result of nonlinear equilibrium kinematics of rods inducing configurational forces, so that deflection of the arms becomes necessary for equilibrium, which would be impossible for a rigid system. In particular, the rigid arms of usual scales are replaced by a flexible elastic lamina, free to slide in a frictionless and inclined sliding sleeve, which can reach a unique equilibrium configuration when two vertical dead loads are applied. Prototypes designed to demonstrate the feasibility of the system show a high accuracy in the measurement of load within a certain range of use. Finally, we show that the presented results are strongly related to snaking of confined beams, with implications for locomotion of serpents, plumbing and smart oil drilling. PMID:25197248

  20. Squeezed helical elastica.

    PubMed

    Bouzar, Lila; Müller, Martin Michael; Gosselin, Pierre; Kulić, Igor M; Mohrbach, Hervé

    2016-11-01

    We theoretically study the conformations of a helical semi-flexible filament confined to a flat surface. This squeezed helix exhibits a variety of unexpected shapes resembling circles, waves or spirals depending on the material parameters. We explore the conformation space in detail and show that the shapes can be understood as the mutual elastic interaction of conformational quasi-particles. Our theoretical results are potentially useful to determine the material parameters of such helical filaments in an experimental setting.

  1. Polysaccharides derived from Yamoa™ (Funtumia elastica) prime γδ T cells in vitro and enhance innate immune responses in vivo

    PubMed Central

    Graff, Jill C.; Kimmel, Emily M.; Freedman, Brett; Schepetkin, Igor A.; Holderness, Jeff; Quinn, Mark T.; Jutila, Mark A.; Hedges, Jodi F.

    2009-01-01

    Yamoa™ (ground bark of Funtumia elastica tree) is marketed and sold as a dietary supplement with anecdotal therapeutic effects in the treatment of asthma and hay fever. We determined that Yamoa™ and Yamoa™-derived polysaccharides affected innate immunity, in part, by priming γδ T cells. Gene expression patterns in purified bovine γδ T cells and monocytes induced by Yamoa™ were similar to those induced by ultrapure lipopolysaccharide (uLPS). In the presence of accessory cells, Yamoa™ had priming effects that were similar to those of LPS on bovine and murine γδ T cells, but much more potent than LPS on human γδ T cells. The bioactive component of Yamoa™ was delineated to a complex polysaccharide fraction (Yam-I). Intraperitoneal injection of Yamoa™ and Yam-I in mice induced rapid increases in peritoneal neutrophils directed by changes in chemokine expression. In support of a unique agonist found in Yam-I, similar peritonitis responses were also observed in TLR4- and MyD88- deficient mice. Therapeutic treatment with Yam-I resulted in decreased bacterial counts in feces from mice with Salmonella enterica serotype Typhimurium (ST)-induced enterocolitis. This characterization of the immune stimulatory properties of polysaccharides derived from Yamoa™ suggests mechanisms for the anecdotal positive effects of its ingestion and that these polysaccharides show potential for application in innate protection from disease. PMID:19671448

  2. 16S rRNA gene sequences analysis of Ficus elastica rubber latex degrading thermophilic Bacillus strain ASU7 isolated from Egypt.

    PubMed

    Hesham, Abd El-Latif; Mohamed, Nadia H; Ismail, Mady A; Shoreit, Ahmed A M

    2012-09-01

    A thermophilic Bacillus strain ASU7 was isolated from soil sample collected from Assiut governorate in Upper Egypt on latex rubber-containing medium at 45 °C. Genetically, the 16S bacterial ribosomal RNA gene of the strain ASU7 was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank database. Based on phylogenetic analyses, strain ASU7 was identified as Bacillus amyloliquefaciens. The strain was able to utilize Ficus elastica rubber latex as a sole source for carbon and energy. The ability for degradation was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol), and inherent viscosity (dl/g) of the latex. Moreover, the degradation was also confirmed by observing the growth of bacterium and formation of aldehyde or keto group using scanning electron microscopy (SEM) and shiff's reagent, respectively.

  3. Antihyperon-Hyperon production in antiproton-proton annihilations with PANDA at FAIR

    NASA Astrophysics Data System (ADS)

    Papenbrock, Michael

    2016-03-01

    Hyperon production is an excellent probe of QCD in the confinement domain, and spin observables are a powerful tool in understanding the underlying physics. For the Ω hyperon, seven polarisation parameters can be extracted from the angular distributions of its decay products with the future PANDA experiment at FAIR. Simulation studies reveal great prospects for strange and single charmed hyperon channels with PANDA. Software tools supporting these investigations are currently under development.

  4. Two-Body Electromagnetic Final States Produced in Anti-proton - Proton Annihilations

    SciTech Connect

    Broemmelsiek, Daniel Robert

    1995-01-01

    We report on the search for top quark production in $p\\overline{p}$ collisions at $\\sqrt{s}$ = 1.8 TeV using the CDF detector at the Fermilab TeVatron. We assume Standard Model couplings and search for an excess of events consistent with the decay $t\\overline{t} \\to W^{+} bW^- \\overline{b}$. We utilize the excellent resolution of the SVX silicon vertex detector to identify the presence of b quarks via their secondary displaced vertex. We observe 32 candidate events in which 40 jets are identified as b-quark jets. The background is estimated to be 10.0 $\\pm$ 2.8 tagged jets. The probability that a background fluctuation can account for the observed excess is 2.8 x $10^{-6}$ , which corresponds to 4.5$\\sigma$ on a Gaussian distribution. These data firmly establish the existence of the top quark. We use a kinematic fitting procedure to directly determine the top quark mass. We measure $M_t$ = 175 $\\pm$ 11 GeV/$c^2$ . Assuming t he measured mass we calculate the $t\\overline{t}$ production cross section to be $\\sigma_{t\\overline{t}}$ = 6.2 $\\pm$ 1.9 pb. Both the measured mass and the cross section are consistent with Standard Model expectations.

  5. Perspective Study of Charmonium and Exotics in Antiproton-Proton Annihilation and Proton-Proton Collisions

    NASA Astrophysics Data System (ADS)

    Barabanov, Mikhail; Olsen, Stephen; Vodopyanov, Alexander

    The spectroscopy of exotic states with hidden charm is discussed. Together with charmonium, these provide a good tool for testing theories of the strong interactions including both perturbative and non-perturbative QCD, lattice QCD, potential and other phenomenological models. An elaborated analysis of exotics spectrum is given, and attempts to interpret recent experimentally observed states with masses above the Dbar{D} threshold region are considered. Experimental results from different collaborations (BES, BaBar, Belle, LHCb) are analyzed with special attention given to recently discovered hidden charm states. Some of these states can be interpreted as higher-lying charmonium states and others as tetraquarks with hidden charm. It has been shown that charged/neutral tetraquarks must have their neutral/charge partners with mass values differ by at most a few MeV/c2, hypotheses that tend to coincide with those proposed by Maiani and Polosa. However, measurements of different decay modes are needed before firm conclusions can be made. These data can be derived directly from the experiments using a high quality antiproton beam with momentum up to 15 GeV/c and proton-proton collisions with momentum up to 26 GeV/c.

  6. Phenomenological study of exclusive binary light particle production from antiproton-proton annihilation at FAIR/PANDA

    NASA Astrophysics Data System (ADS)

    Ying, Wang

    2016-08-01

    Exclusive binary annihilation reactions induced by antiprotons of momentum from 1.5 to 15 GeV/c can be extensively investigated at FAIR/PANDA [1]. We are especially interested in the channel of charged pion pairs. Whereas this very probable channel constitutes the major background for other processes of interest in the PANDA experiment, it carries unique physical information on the quark content of proton, allowing to test different models (quark counting rules, statistical models,..). To study the binary reactions of light meson formation, we are developing an effective Lagrangian model based on Feynman diagrams which takes into account the virtuality of the exchanged particles. Regge factors [2] and form factors are introduced with parameters which may be adjusted on the existing data. We present preliminary results of our formalism for different reactions of light meson production leading to reliable predictions of cross sections, energy and angular dependencies in the PANDA kinematical range.

  7. The charmonium [sup 1]P[sub 1] state (h[sub c]) produced in antiproton-proton annihilations

    SciTech Connect

    Gollwitzer, K.E.

    1993-01-01

    A search for the charmonium [sup 1]P[sub 1] state (h[sub c]) has been performed in [bar p]p annihilations close to the spin weighted center of gravity of the triplet P states. A statistically significant enhancement in the [bar p]p [r arrow] J/[psi][pi][degrees] cross section has been observed with characteristics consistent with the expected mass, total width, and production cross section the singlet P wave state. The resonance is centered at [radical][sub 3][approx equal]3526.15 [+-] 0.15[+-]0.19 MeV, greater than the center of gravity of the triplet P states by 0.88 [+-] 0.47 MeV. The upper limit (0% CL) for the total width is [<=]1.1 MeV. No candidates for the reactions [bar p]p [r arrow]J/[psi][pi][degrees][pi][degrees] and pp [r arrow] J/[psi][pi][sup +][pi][sup [minus

  8. Perspective study of exotics and flavour baryons in antiproton-proton annihilation and proton-proton collisions

    NASA Astrophysics Data System (ADS)

    Barabanov, Mikhail; Vodopyanov, Alexander

    2016-07-01

    Abstract. The spectroscopy of exotic states with hidden charm is discussed. Together with charmonium, these provide a good tool for testing theories of the strong interactions including both perturbative and non-perturbative QCD, lattice QCD, potential and other phenomenological models. An elaborated analysis of exotics spectrum is given, and attempts to interpret recent experimentally observed states with masses above the DD̅ threshold region are considered. Experimental results from different collaborations (BES, BaBar, Belle, LHCb) are analyzed with special attention given to recently discovered hidden charm states. Some of these states can be interpreted as higher-lying charmonium states and others as tetraquarks with hidden charm. It has been shown that charged/neutral tetraquarks must have their neutral/charge partners with mass values differ by at most a few MeV/c2, hypotheses that tend to coincide with those proposed by Maiani and Polosa. However, measurements of different decay modes are needed before firm conclusions can be made. These data can be derived directly from the experiments using ahigh quality antiproton beam with momentum up to 15 GeV/c and proton-proton collisions with momentum up to 26 GeV/c. DD

  9. Conceptual Design Report. Antiproton - Proton Collider Upgrade 20 GeV Rings. Technical Components and Civil Construction May, 1988

    SciTech Connect

    1988-05-01

    This report contains a description of the design and cost estimate of two new 20 GeV rings which will be required to support the upgrade of the Fermilab Collider with a luminosity goal of 5x10 31 cm-2s-1. The new rings include an antiproton post-accumulator, denoted the Antiproton Super Booster (ASB), and a proton post-booster, denoted the Proton Super Booster (PSB). The siting of the rings is shown in Figure I-1. Both rings are capable of operation at 20 GeV, eliminating the need for ever again injecting beam into the Main Ring below transition, and significantly enhancing Main Ring performance. The Antiproton Super Booster is designed to accept and accumulate up to 4x1012 antiprotons from the existing Antiproton Accumulator, and deliver them to the Main Ring at 20 GeV for acceleration and injection into the Collider. It is also designed to accept diluted antiprotons from the Main Ring at 20 GeV for recooling. The PSB accepts 8.9 GeV protons from the existing Booster and accelerates them to 20 GeV for injection into the Main Ring. The PSB is designed to operate at 5 Hz. The siting shown in Figure I-1 has the attractive feature that it removes all Main Ring injection hardware from the AO straight section, opening the possibility of installing a third proton-antiproton interaction region in the Tevatron Collider.

  10. Search for the Top Quark in Antiproton-Proton Collisions at SQRT.S = 1.8 Tev

    NASA Astrophysics Data System (ADS)

    Walsh, John Joseph

    1990-01-01

    A search for the top quark in | p p collisions at a center of mass energy of 1.8 TeV using the Collider Detector at Fermilab is described. A study of events selected by requiring an energetic electron, missing transverse energy, and two or more jets excludes at 95% confidence level the Standard Model production and decay of t| t pairs if the top quark mass is between 40 and 77 GeV/c^2 . The observed electron + multijet data are consistent with W boson production.

  11. Floppy swimming: viscous locomotion of actuated elastica.

    PubMed

    Lauga, Eric

    2007-04-01

    Actuating periodically an elastic filament in a viscous liquid generally breaks the constraints of Purcell's scallop theorem, resulting in the generation of a net propulsive force. This observation suggests a method to design simple swimming devices-which we call "elastic swimmers"-where the actuation mechanism is embedded in a solid body and the resulting swimmer is free to move. In this paper, we study theoretically the kinematics of elastic swimming. After discussing the basic physical picture of the phenomenon and the expected scaling relationships, we derive analytically the elastic swimming velocities in the limit of small actuation amplitude. The emphasis is on the coupling between the two unknowns of the problems-namely the shape of the elastic filament and the swimming kinematics-which have to be solved simultaneously. We then compute the performance of the resulting swimming device and its dependence on geometry. The optimal actuation frequency and body shapes are derived and a discussion of filament shapes and internal torques is presented. Swimming using multiple elastic filaments is discussed, and simple strategies are presented which result in straight swimming trajectories. Finally, we compare the performance of elastic swimming with that of swimming micro-organisms.

  12. Measurement of the cosmic ray antiproton/proton flux ratio at TeV energies with the ARGO-YBJ detector

    NASA Astrophysics Data System (ADS)

    Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Bolognino, I.; Branchini, P.; Budano, A.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Chen, S. Z.; Chen, T. L.; Chen, Y.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Alí Staiti, G.; Danzengluobu; de Mitri, I.; D'Ettorre Piazzoli, B.; di Girolamo, T.; Ding, X. H.; di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Giroletti, E.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Montini, P.; Ning, C. C.; Pagliaro, A.; Panareo, M.; Panico, B.; Perrone, L.; Pistilli, P.; Qu, X. B.; Ruggieri, F.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, Jilong; Zhang, Jianli; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxiciren; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.

    2012-01-01

    Cosmic ray antiprotons provide an important probe to study the cosmic ray propagation in the interstellar space and to investigate the existence of dark matter. Acting the Earth-Moon system as a magnetic spectrometer, paths of primary antiprotons are deflected in the opposite sense with respect to those of the protons in their way to the Earth. This effect allows, in principle, the search for antiparticles in the direction opposite to the observed deficit of cosmic rays due to the Moon (the so-called “Moon shadow”). The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l., 606g/cm2), is particularly effective in measuring the cosmic ray antimatter content via the observation of the cosmic rays shadowing effect due to: (1) good angular resolution, pointing accuracy and long-term stability; (2) low energy threshold; (3) real sensitivity to the geomagnetic field. Based on all the data recorded during the period from July 2006 through November 2009 and on a full Monte Carlo simulation, we searched for the existence of the shadow cast by antiprotons in the TeV energy region. No evidence of the existence of antiprotons is found in this energy region. Upper limits to the p¯/p flux ratio are set to 5% at a median energy of 1.4 TeV and 6% at 5 TeV with a confidence level of 90%. In the TeV energy range these limits are the lowest available.

  13. Search for the Top Quark Decaying to a Charged Higgs Boson in Antiproton-Proton Collisions at 1.8 Tev

    NASA Astrophysics Data System (ADS)

    Wang, Jinsong

    This paper presents the results of a search in overline{p}p collisions at sqrt{s} = 1.8 TeV for the top quark decaying to a charged Higgs boson (H ^+/-) and a bottom quark. We search for dilepton final states from the decay chain t overline{t} to HH (or HW, or WW) + boverline{b} to ll + X. In a sample of 19.3 pb^{-1} collected during 1992-93 with the Collider Detector at Fermilab (CDF), we observe 2 events with a background estimation of 3.0 +/- 1.0 events. Limits at 95% C.L. in the (M_{t}, M _{H}) plane are presented. We also interpret the results in terms of the parameter tan beta of two-Higgs-doublet models.

  14. Diffractive processes in antiproton-proton collision at √s = 1.96 TeV in the D0 experiment

    SciTech Connect

    Otec, Roman

    2006-01-01

    A first study of single diffractive central high-pT dijet events in p$\\bar{p}$ collisions at center-of-mass energy √s = 1.96 TeV is presented, using data recorded by the D0 detector at the Tevatron during RunIIa in 2002-2004. The total integrated luminosity corresponding to the data sample is 398 pb-1. A diffractive sample is selected using a rapidity gap approach. A precise definition of the rapidity gap constitutes the first part of the thesis. The rapidity gap is defined by means of two parts of the D0 detector--luminosity detectors and calorimeter. Luminosity detectors serve as a basic indicators of diffractive candidates and the calorimeter is used to confirm the low energy activity in the forward region (a rapidity gap). Presented studies of energy deposited in forward part of calorimeter by various types of events yield two rapidity gap definitions. Both of them use a fixed rapidity interval in calorimeter |η| ϵ [2.6,5.2] and introduce an upper limit on the energy deposited in this region. First definition, which corresponds to the lowest systematical errors, uses a limit of 10 GeV, an energy limit in the second definition is set to 3 GeV. This alternative definition corresponds to the lowest contamination of diffractive sample by non-diffractive events, on the other hand it is accompanied with rejection of high percentage of diffractive candidates. Using the gap definition dijet diffractive data are then selected and compared to inclusive dijet events in various distributions. The main focus is to measure the difference in azimuthal angles between two leading jets in events with at least two high pt central jets. This variable is sensitive to the dynamics of the process. Indeed, the results show the different behavior of ΔΦ distributions between the inclusive and diffractive samples. It is also shown that this difference is bigger for lower pT jets. Other distributions presented in the thesis show that most of the properties are the same for inclusive and diffractive events. The only observed difference is in the transversal properties of the jets, which could be explained as that diffractive jets are narrower than inclusive ones. Results are compared to Monte Carlo Pomwig (for diffractive sample) and Herwig (for inclusive sample); both show a good agreement with the data.

  15. Twirling and Whirling: Viscous Dynamics of Rotating Elastica

    NASA Astrophysics Data System (ADS)

    Wolgemuth, Charles; Powers, Thomas; Goldstein, Raymond

    1999-10-01

    The stability of forced elastic filaments arise in several important biological settings involving bend and twist elasticity at low Reynolds number. Examples include DNA transcription and replication and bacterial flagellar motion. In order to elucidate fundamental processes common to these systems, we consider the model problem of a rotationally forced filament with twist and bend elasticity. Competition between twist injection, twist diffusion, and writhing instabilities is described by a novel pair of PDEs for twist and bend evolution. Analytical and numerical methods elucidate the twist/bend coupling and reveal two dynamical regimes seperated by a Hopf bifurcation: (i) diffusion-dominated axial rotation, or twirling, and (ii) steady-state crankshafting motion, or whirling. Experiments are proposed to examine these phenomena and the consequences for swimming investigated.

  16. Twirling and Whirling: Viscous Dynamics of Rotating Elastica

    NASA Astrophysics Data System (ADS)

    Powers, Thomas R.; Wolgemuth, Charles W.; Goldstein, Raymond E.

    1999-11-01

    Motivated by diverse phenomena in cellular biophysics, including bacterial flagellar motion and DNA transcription and replication, we study the overdamped nonlinear dynamics of a rotationally forced filament with twist and bend elasticity. The competition between twist diffusion and writhing instabilities is described by a novel pair of coupled PDEs for twist and bend evolution. Analytical and numerical methods elucidate the twist-bend coupling and reveal two dynamical regimes separated by a Hopf bifurcation: (i) diffusion-dominated axial rotation, or twirling, and (ii) steady-state crankshafting motion, or whirling. The consequences of these phenomena for self-propulsion are investigated, and experimental tests proposed.

  17. Study of the Positive Kaon Neutral Antikaon Negative Pion System Produced in the Reaction Antiproton-Proton Going to Positive Kaon Neutral Antikaon Negative Pion + Chi at 8 Gev/c

    NASA Astrophysics Data System (ADS)

    Boehnlein, Amber Stephanie

    1990-01-01

    The results of an amplitude analysis to determine the spin-parity components of the K^+{ | K^0} pi^{-} system produced in the reaction { | p}pto K^+{| K^0 }pi^- + X at 8 GeV/c are presented. This experiment has better particle identification than the previously reported results examining this reaction. A total of 3595 events was collected in the mass range 1.24 -1.56 GeV/c^2. The data were collected at the Brookhaven National Laboratory Multi-Particle Spectrometer. Two peaks are observed in the K^+{| K^0}pi^- mass spectrum, one at (1279 +/- 2) MeV/c ^2 with a width of 21 +/- 2) MeV/c^2, and one at (1417 +/- 3) MeV/c^2 with a width of (62 +/- 5) MeV/c ^2. There is evidence for two resonances around 1.3 GeV/c^2. The J^ {PG} = 1^{++} resonance that peaks near 1.27 Gev/c^2 is identified with the f_1(1285). The J^{PG} = 0^ {-+} resonance observed at the same mass is identified with the eta(1280). In the 1.4 GeV/c^2 range, the data are consistant with the presence of at least one J^{PG} = 0^ {-+} resonance that peaks near 1.43 GeV/c ^2. This resonance decays only to a_{0}pi. There is also evidence for a 1^{++}K ^{*}K resonance that peaks around 1.40 GeV/c^2. These results are in agreement with the results from the partial wave analysis performed by members of this collaboration on the K^+{| K^0} pi^- system produced in the reaction pi^-pto K^+{| K^0}pi^-n at 8 GeV/c. This experiment also examined the reactions {| p}pto{| Lambda }p+pi s+X in a search for the U(3100). No evidence for the U(3100) is observed.

  18. SAR detected river mixing and coastal wave/current difusion

    NASA Astrophysics Data System (ADS)

    Diez, Margarita; Martinez-Benjamin, Juan Jose; Sekula, Emil

    2014-05-01

    The Synthetic Aperture Radar SAR is an active radar which emits its energy in the centimetre frequencies. Due to the large orbital velocity of the satellite (7.5km s-1) approximately, the path of the antenna itself may be converted as a virtual antenna of a much larger size. The SAR instrument may also be installed on a plane, or on a helicopter. The SAR backscattering depends on the roughness of the small scale surface of the ocean. When the surface is rougher (mostly due to capillary waves in the surface) the intensity of the receiving signal is stronger due to Bragg resonant dispersion [1,2] and a white zone is observed in the image when the surface is very rough. Rivers and tensioactive slicks and spills are well detected as dark areas in the ocean surface. An image selection of SAR images in order to identify coastal river plumes or oil spills of more than 1000 ERS-1/2 and RADARSAT Synthetic Aperture Radar SAR images for the test site in the NW Mediterranean seawere clasified and stored by [2,3,7] during the "Clean Seas" International project and the "Marine pollution and surface dynamics in the NW Mediterranean Sea" European Spatial Agency ESA project AO-ID C1P.2240. A geometry of gray scale ranges and boundaries of spatial dynamic surface features may contain new helpful information about the turbulent structure at different distances from the coast. Already we used multi-fractal analysis techniques to investigate man-made oil spills [3-5] We apply these techniques to the analysis of ocean surface multi-fractal features (eddies, mushroom-like currents, etc.) to understand the scale to scale transport and coastal effects. (Redondo et al. 1998)(Diez et al. 2008) [4,7]. The effect of bathymetry and local currents are important in describing the ocean surface behavior. In the NW Mediterranean the maximum eddy size agrees remarkably well with the limit imposed by the local Rossby deformation radius using the usual thermocline induced stratification, the distribution of eddies and oil spills also mark the topology of the mixing [5-9]. A series of experimental measurements of the Lagrangian characteristics of the surface currents near Barcelona and Vilanova were performed during several years for different wind and wave conditions. The seasonal influence on the water recirculation and the influence of local conditions is apparent when the formation of a local thermocline also forces strong Langmuir circulations. Understanding the dispersion of very large freshwater discharge from the Rhone and the Ebro into the Mediterranean Sea and its impact on the biology and biogeochemistry of western Mediterranean. Because of the lack of tides and prevalence of strong wind forcing by the Mistral and Tramontana winds, the discharge of the rivers forms a classical example of a wind powered ROFI. The Fractal analysis indicates a river induced anisotropy anomalous surface mixing [6,7] Emil Sekula acknowledges the grants (SGR99-00145). ESP2005-07551, RYC-2003-005700). Authors also acknowledge the (ENV4-CT96-0334) European Union Project and the ESA (AO-ID C1P.2240) [1] Carrillo, A.; Sanchez, M.A.; Platonov, A.; Redondo, J.M., (2001). Coastal and Interfacial Mixing. Laboratory Experiments and Satellite Observations. Physics and Chemistry of the Earth, B, 26/4.305-311. [2] Sekula E., Redondo J. M. (2008) The structure of turbulent jets, vortices and boundary layer: Laboratory and field observations, Il Nuovo Cimento, Vol. 31, N. 5-6, 2008, DOI 10.1393/ncc/i2009-10358-y, 893-907. [3] B. Shirasago, V. Palà Comellas, J. J. Martínez Benjamín, D. Sánchez, A. Martínez, J. Font, R. Arbiol, J. Vázquez, V. Moreno (1996) Revista de teledetección: Revista de la Asociación Española de Teledetección, ISSN 1133-0953, Nº. 6. [4] J. M. Redondo, M. A. Sanchez, J. J. Martinez-Benjamin, and G. S. Jolly (1998)Spectral study of the ocean surface with SAR Proc. SPIE 3496, 217. [5] J. J. Martinez-Benjamin, C. Medeiros, O. Chic, M. O. Bezerra, and J. M. Redondo(1998) Incidence of SAR images on the study of NE-Brazilian coast and shelf waters Proc. SPIE 3496, 212. [6] Mahjoub O., Redondo J.M. y R. Alami (1998) Turbulent Structure Functions in Geophysical Flows, Rapp Comm. int Mer Medit. 35}, 126. [7] Diez M., Bezerra M.O., Mosso C., Castilla R. and Redondo J.M. (2008) Experimental measurements and diffusion in harbor and coastal areas. Il Nuovo Cimento C 31, 5-6, 843-859. [8] Redondo J.M. and Platonov A. (2009) Self-similar distribution of oil spills in European coastal waters. Environ. Res. Lett. 4, 14008.

  19. The energetics of tightly bent DNA: a composite elastica model including local melting

    NASA Astrophysics Data System (ADS)

    Evans, Arthur; Levine, Alex

    2012-02-01

    Melting transitions are well-known to be affected by the application of mechanical stress. Motivated by the experiments of Zocchi and collaborators (Qu and Zocchi 2011, EPL 94 18003), we explore the effect of the application of mechanical stress on DNA melting in a particular composite of a stiff double stranded piece of DNA (dsDNA), shorter than its own persistence length, whose ends are linked by a flexible single stranded piece of DNA (ssDNA). The flexible ssDNA acts as a Gaussian polymer coil bending the stiff dsDNA through an elastic force that is controllable by the length of the ssDNA chain. In this talk we present theoretical predictions for two experimentally accessible features: the degree of local dsDNA melting and the local elastic energy of the dsDNA/ssDNA construct both as a function of the length of the attached ssDNA. We also address the effect of introducing a nick (broken covalent bond) in the dsDNA backbone on these results and discuss the implications of such data on the relative importance of backbone elasticity versus base stacking and base pairing interactions in determining the elasticity of dsDNA. This work also addresses open questions in the nonlinear elasticity of DNA in tightly bent curves.

  20. The magneto-elastica: from self-buckling to self-assembly

    PubMed Central

    Vella, Dominic; du Pontavice, Emmanuel; Hall, Cameron L.; Goriely, Alain

    2014-01-01

    Spherical neodymium–iron–boron magnets are permanent magnets that can be assembled into a variety of structures owing to their high magnetic strength. A one-dimensional chain of these magnets responds to mechanical loadings in a manner reminiscent of an elastic rod. We investigate the macroscopic mechanical properties of assemblies of ferromagnetic spheres by considering chains, rings and chiral cylinders of magnets. Based on energy estimates and simple experiments, we introduce an effective magnetic bending stiffness for a chain of magnets and show that, used in conjunction with classic results for elastic rods, it provides excellent estimates for the buckling and vibration dynamics of magnetic chains. We then use this estimate to understand the dynamic self-assembly of a cylinder from an initially straight chain of magnets. PMID:24511257

  1. Deformation and Flexibility Equations for ARIS Umbilicals Idealized as Planar Elastica

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Leamy, Michael J.; Bryant, Paul J.; Quraishi, Naveed

    2005-01-01

    The International Space Station relies on the active rack isolation system (ARIS) as the central component of an integrated, stationwide strategy to isolate microgravity space-science experiments. ARIS uses electromechanical actuators to isolate an international standard payload rack from disturbances due to the motion of the Space Station. Disturbances to microgravity experiments on ARIS isolated racks are transmitted primarily via the ARIS power and vacuum umbilicals. Experimental tests indicate that these umbilicals resonate at frequencies outside the ARIS controller s bandwidth at levels of potential concern for certain microgravity experiments. Reduction in the umbilical resonant frequencies could help to address this issue. This work documents the development and verification of equations for the in-plane deflections and flexibilities of an idealized umbilical (thin, flexible, inextensible, cantilever beam) under end-point, in-plane loading (inclined-force and moment). The effect of gravity is neglected due to the on-orbit application. The analysis assumes an initially curved (not necessarily circular), cantilevered umbilical with uniform cross-section, which undergoes large deflections with no plastic deformation, such that the umbilical slope changes monotonically. The treatment is applicable to the ARIS power and vacuum umbilicals under the indicated assumptions.

  2. Dynamics of novel forests of Castilla elastica in Puerto Rico: from species to ecosystems

    Treesearch

    Jessica Fonseca da Silva

    2015-01-01

    Novel forests (NFs)—forests that contain a combination of introduced and native species—are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the...

  3. Species composition, diversity and structure of novel forests of Castilla elastica in Puerto Rico

    Treesearch

    J. Fonseca da Silva; NO-VALUE

    2014-01-01

    Attributes of novel forests (secondary forests containing introduced species) were compared with those of native secondary forests of similar age. The study area was the biological reserve called El Tallonal, in Puerto Rico. Species composition, tree density, basal area and soil bulk density were characterized; Importance value index (IVI), Shannon’s diversity index (H...

  4. Generalized elastica patterns in a curved rotating Hele-Shaw cell

    NASA Astrophysics Data System (ADS)

    Brandão, Rodolfo; Miranda, José A.

    2017-08-01

    We study a family of generalized elasticalike equilibrium shapes that arise at the interface separating two fluids in a curved rotating Hele-Shaw cell. This family of stationary interface solutions consists of shapes that balance the competing capillary and centrifugal forces in such a curved flow environment. We investigate how the emerging interfacial patterns are impacted by changes in the geometric properties of the curved Hele-Shaw cell. A vortex-sheet formalism is used to calculate the two-fluid interface curvature, and a gallery of possible shapes is provided to highlight a number of peculiar morphological features. A linear perturbation theory is employed to show that the most prominent aspects of these complex stationary patterns can be fairly well reproduced by the interplay of just two interfacial modes. The connection of these dominant modes to the geometry of the curved cell, as well as to the fluid dynamic properties of the flow, is discussed.

  5. A generalized analytical approach to the coupled effect of SMA actuation and elastica deflection

    NASA Astrophysics Data System (ADS)

    Sreekumar, M.; Singaperumal, M.

    2009-11-01

    A compliant miniature parallel manipulator made of superelastic nitinol pipe as its central pillar and actuated by three symmetrically attached shape memory alloy (SMA) wires is under development. The mobility for the platform is obtained by the selective actuation of one or two wires at a time. If one wire is actuated, the other two unactuated wires provide the counter effect. Similarly, if two wires are actuated simultaneously or in a differential manner, the third unactuated wire resists the movement of the platform. In an earlier work of the authors, the static displacement analysis was presented without considering the effect of unactuated wires. In this contribution, the force-displacement analysis is presented considering the effect of both actuated and unactuated wires. Subsequently, an attempt has been made to obtain a generalized approach from which six types of actuation methods are identified using a group of conditional parameters. Each method leads to a set of large deflection expressions suitable for a particular actuation method. As the large deflection expressions derived for the mechanism are nonlinear and involve interdependent parameters, their simplified form using a parametric approximation have also been obtained using Howell's algorithm. The generalized approach and the solution algorithm developed can be applied to any kind of compliant mechanism having large deflection capabilities, including planar and spatial MEMS devices and stability analysis of long slender columns supported by wires or cables. The procedure developed is also suitable for the static analysis of spatial compliant mechanisms actuated by multiple SMA actuators.

  6. The History of the Planar Elastica: Insights into Mechanics and Scientific Method

    ERIC Educational Resources Information Center

    Goss, Victor Geoffrey Alan

    2009-01-01

    Euler's formula for the buckling of an elastic column is widely used in engineering design. However, only a handful of engineers will be familiar with Euler's classic paper "De Curvis Elasticis" in which the formula is derived. In addition to the Euler Buckling Formula, "De Curvis Elasticis" classifies all the bent configurations of elastic rod--a…

  7. The History of the Planar Elastica: Insights into Mechanics and Scientific Method

    ERIC Educational Resources Information Center

    Goss, Victor Geoffrey Alan

    2009-01-01

    Euler's formula for the buckling of an elastic column is widely used in engineering design. However, only a handful of engineers will be familiar with Euler's classic paper "De Curvis Elasticis" in which the formula is derived. In addition to the Euler Buckling Formula, "De Curvis Elasticis" classifies all the bent configurations of elastic rod--a…

  8. Bubble-raft collapse and the nonequilibrium dynamics of two-state elastica

    NASA Astrophysics Data System (ADS)

    Kuo, Chin-Chang; Kachan, Devin; Levine, Alex J.; Dennin, Michael

    2016-03-01

    We report on the collapse of bubble rafts under compression in a closed rectangular geometry. A bubble raft is a single layer of bubbles at the air-water interface. A collapse event occurs when bubbles submerge beneath the neighboring bubbles under compression, causing the structure of the bubble raft to go from single-layer to multilayer. We studied the collapse dynamics as a function of compression velocity. At higher compression velocity we observe a more uniform distribution of collapse events, whereas at lower compression velocities the collapse events accumulate at the system boundaries. We propose that this system can be understood in terms of a linear elastic sheet coupled to a local internal (Ising) degree of freedom. The two internal states, which represent one bubble layer versus two, couple to the elasticity of the sheet by locally changing the reference state of the material. By exploring the collapse dynamics of the bubble raft, one may address the basic nonlinear mechanics of a number of complex systems in which elastic stress is coupled to local internal variables.

  9. Bubble-raft collapse and the nonequilibrium dynamics of two-state elastica.

    PubMed

    Kuo, Chin-Chang; Kachan, Devin; Levine, Alex J; Dennin, Michael

    2016-03-01

    We report on the collapse of bubble rafts under compression in a closed rectangular geometry. A bubble raft is a single layer of bubbles at the air-water interface. A collapse event occurs when bubbles submerge beneath the neighboring bubbles under compression, causing the structure of the bubble raft to go from single-layer to multilayer. We studied the collapse dynamics as a function of compression velocity. At higher compression velocity we observe a more uniform distribution of collapse events, whereas at lower compression velocities the collapse events accumulate at the system boundaries. We propose that this system can be understood in terms of a linear elastic sheet coupled to a local internal (Ising) degree of freedom. The two internal states, which represent one bubble layer versus two, couple to the elasticity of the sheet by locally changing the reference state of the material. By exploring the collapse dynamics of the bubble raft, one may address the basic nonlinear mechanics of a number of complex systems in which elastic stress is coupled to local internal variables.

  10. Second-Order Characteristic Methods for Advection-Difusion Equations and Comparison to Other Schemes

    DTIC Science & Technology

    1997-01-01

    and for nonlinear equations as well as nite volume formulations However because the characteristics for variablecoecient...there are more improved versions of SDM method with shock capturing capacity which produce better approximations they usually have nonlinear ... optimally ecient and reasonable choice of space and time steps to produce a qualitatively comparable solution to that of the BRKC and FRKC schemes in

  11. The polysulfonated compound suramin blocks adsorption and lateral difusion of herpes simplex virus type-1 in vero cells.

    PubMed

    Aguilar, J S; Rice, M; Wagner, E K

    1999-05-25

    Several polysulfonate compounds have been shown to have the potential to inhibit the replication of herpesviruses by blocking binding and penetration of the host cell. We analyzed the actions of the polysulfonate compound suramin on the replication of herpes simplex virus type 1 (HSV-1) and compared them with the actions of heparin. We used the expression of a reporter gene (beta-galactosidase) recombined into the latency-associated transcript region of the 17syn+ strain of HSV-1 to quickly evaluate productive cycle activity and have shown that it can be directly correlated with virus replication under the conditions used. We find that suramin, like heparin, blocks the binding of HSV-1 to the cell membrane. Also, suramin efficiently blocks the cell-to-cell spread of the virus; this effect has not been previously reported. Our control experiments demonstrate that heparin also has some effect on intercellular spread of HSV-1 but to a significantly lesser degree than does suramin. We suggest that suramin and related polysulfonate compounds have potential for developing of antiherpes treatments. Copyright 1999 Academic Press.

  12. Experimentation and Analysis of Compression Test Methods for Single Filament High Performance Fibres

    DTIC Science & Technology

    1988-12-01

    2 1.3 Background.......................................... 2 1.4 Previous Studies.................................... 3 Elastica ...5 Numerical Analysis of Elastica .................... 5 1.5 Thesis Presentation................................ 6 2. Background...15 Elastica Loop Test................................. 16 Embedding the Fibers in the Matrix................ 17 Recoil Test

  13. A study of Two Photon Decays of Charmonium Resonances Formed in Proton Anti-Proton Annihilations

    SciTech Connect

    Pedlar, Todd Kristofer

    1999-06-01

    In this dissertation we describe the results of an investigation of the production of charmonium states (ηc, η'c, χ0 and χ2) in Fermilab experiment E835 via antiproton-proton annihilation and their detection via their decay into two photons.

  14. That was LEAP 05! or Antiproton Physics in a Nutshell

    NASA Astrophysics Data System (ADS)

    Kienle, Paul

    2005-10-01

    A personally flavored review of selected topics of LEAP 05 is given, with focus on some recent interesting developments in low and medium energy antiproton physics, such as fundamental symmetries and antihydrogen, antihadron-hadron systems, antiproton-proton annihilation, nuclear structure studies with antiprotons, and the FAIR facility for antiproton and ion research.

  15. The E760 Jet Target: Measurements of performance at 77K

    SciTech Connect

    Boero, G.; Macri, M.; Robutti, E.; Allspach, D.; Kendziora, C.; Marinelli, M.

    1994-11-01

    In this report we describe the measurements performed on the E760 hydrogen Jet Target in order to some of the basic parameters of the system. These measurements were performed in the context of the upgrade program of the target for the successor experiment E835. Fermilab experiment E760 studied charmonium states formed in antiproton-proton annihilations. The antiproton-proton interactions were produced in a jet of hydrogen gas which intersected the antiproton beam coasting in the Fermilab Antiproton Accumulator. The results from E760 have shown that an increase in integrated luminosity by a factor of more than 5 is needed to complete the study of the charmonium spectrum. The E835 experiment is designed to achieve this by increasing the intensity of the antiproton beam and the density of the hydrogen-cluster-jet. This report is concerned with preparations for the work needed to increase the density of the hydrogen-cluster-jet.

  16. Vibration Suppression Strategies for Large Tension-Aligned Array Structures

    DTIC Science & Technology

    2013-11-19

    the antenna consists of a series of linked semi-rigid panels connected to a catenary cable network. The highly flexible and low damping nature of the...elastica arch Figure 3: A tension-aligned structure constructed by connecting a support structure (in compres- sion) to an array of hinged panels (in...structure is presented. The tension-aligned structure, shown in Fig.3, consists of a planar elastica arch support structure in compression and a hinged

  17. Study of the $\\chi_1$ and $\\chi_2$ States Produced in $\\overline{p}p$ Annihilations in Fermilab EXPERIMENT 760

    SciTech Connect

    Marques, Jose Laurencio

    1992-01-01

    A study of the $\\chi_1(^3P_1$) and the $\\chi_2(^3P_2$) states of charmonium formed in antiproton- proton annihilations is reported in this dissertation. Performed at Fermi National Accelerator Laboratory, Experiment 760 used an internal molecular hydrogen jet target and circulating beam of momentum cooled antiprotons to conduct energy scans of the two resonances. The small momentum spread of the antiproton beam allowed very precise measurements of both the resonance mass and total width to be made.

  18. Review of the results of measurements of the fluxes of the charged components of galactic cosmic rays in the experiments PAMELA and AMS-02

    NASA Astrophysics Data System (ADS)

    Alekseev, V. V.; Belotsky, K. M.; Bogomolov, Yu. V.; Budaev, R. I.; Galper, A. M.; Dunaeva, O. A.; Kirillov, A. A.; Kuznetsov, A. V.; Lukyanov, A. D.; Mayorov, A. G.; Mayorova, M. A.; Malakhov, V. V.; Mosichkin, A. F.; Okrugin, A. A.; Rodenko, S. A.; Shitova, A. M.

    2017-09-01

    The paper provides a review of the results of precision measurements of the fluxes of different charged components of galactic cosmic rays (positrons and antiprotons, protons and helium nuclei) in modern experiments with magnetic spectrometers PAMELA and AMS-02, operating successfully for a few years (since 2006 and 2011, respectively) in Earth orbit. A priority of the PAMELA spectrometer scientific discoveries is noted. It is also noted that the measurements from the AMS-02 experiment are of high statistical accuracy and have reliably confirmed previous data, having been able to advance to a higher energy range.

  19. Galactic antiprotons of 0.2-2 GeV energy

    NASA Technical Reports Server (NTRS)

    Bogomolov, E. A.; Vasilyev, G. I.; Iodko, M. G.; Krutkov, S. Y.; Lubyanaya, N. D.; Romanov, V. A.; Stepanov, S. V.; Shulakova, M. S.

    1985-01-01

    Balloon measurements of the galactic antiproton flux in the energy range 0.2 GeV to 2 GeV are presented. The experiments were carried out in the summer of 1984 with magnet spectrometers flown at a residual pressure of approximately 10 g sq cm and cut off rigidity of approximately 0.6 GV. An upper limit for the antiproton to proton flux ratio has been obtained of antiproton/proton (0.2 GeV to 2 GeV) less than 5 x .0001.

  20. Results from ARGO-YBJ

    SciTech Connect

    Iacovacci, M.

    2009-04-08

    The ARGO-YBJ experiment has been put in stable data taking at the YangBaJing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l.). In this paper we report a few selected results in Gamma-Ray Astronomy (Crab Nebula and Mrk421 observations, search for high energy tails of Gamma Ray Bursts) and Cosmic Ray Physics (Moon and Sun shadow observations, proton-air cross section measurement, preliminary measurement of the antiproton/proton ratio at TeV energies)

  1. Highlights from the ARGO-YBJ experiment

    NASA Astrophysics Data System (ADS)

    Aielli, G.; Bacci, C.; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, P.; Budano, A.; Bussino, S.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, P.; Chen, S. Z.; Chen, T. L.; Chen, Y.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Alí Staiti, G.; Danzengluobu; Dattoli, M.; de Mitri, I.; D'Ettorre Piazzoli, B.; de Vincenzi, M.; di Girolamo, T.; Ding, X. H.; di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, F.; Galeotti, P.; Gargana, R.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Montini, P.; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, P.; Qu, X. B.; Rossi, E.; Ruggieri, F.; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, Jilong; Zhang, Jianli; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.

    2012-01-01

    The ARGO-YBJ experiment at YangBaJing in Tibet (4300 m a.s.l.) has been taking data with its full layout since October 2007. Here we present a few significant results obtained in gamma-ray astronomy and cosmic-ray physics. Emphasis is placed on the analysis of gamma-ray emission from point-like sources (Crab Nebula, MRK 421), on the preliminary limit on the antiproton/proton flux ratio, on the large-scale cosmic-ray anisotropy and on the proton-air cross-section. The performance of the detector is also discussed, and the perspectives of the experiment are outlined.

  2. Predicting Proton-Air Cross Sections at {radical}(s) {approx} 30 TeV Using Accelerator and Cosmic Ray Data

    SciTech Connect

    Block, M. M.; Halzen, Francis; Stanev, Todor

    1999-12-13

    We use the high-energy predictions of a QCD-inspired parametrization of all accelerator data on forward proton-proton and antiproton-proton scattering amplitudes, along with Glauber theory, to predict proton-air cross sections at energies near {radical}(s){approx_equal}30 TeV . The parametrization of the proton-proton cross section incorporates analyticity and unitarity and demands that the asymptotic proton is a black disk of soft partons. By comparing with the p -air cosmic ray measurements, our analysis results in a constraint on the inclusive particle production cross section. (c) 1999 The American Physical Society.

  3. Extending the frontiers: Reconciling accelerator and cosmic ray p-p cross sections

    SciTech Connect

    Block, M. M.; Halzen, F.; Stanev, T.

    2000-10-01

    We simultaneously fit a QCD-inspired parametrization of all accelerator data on forward proton-proton and antiproton-proton scattering amplitudes, together with cosmic ray data (using Glauber theory), to predict proton-air and proton-proton cross sections at energies near {radical}(s){approx_equal}30 TeV. The p-air cosmic ray measurements provide a strong constraint on the inclusive particle production cross section, as well as greatly reducing the errors on the fit parameters--in turn, greatly reducing the errors in the high-energy proton-proton and proton-air cross section predictions. (c) 2000 The American Physical Society.

  4. Results from ARGO-YBJ

    NASA Astrophysics Data System (ADS)

    Iacovacci, M.

    2009-04-01

    The ARGO-YBJ experiment has been put in stable data taking at the YangBaJing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l.). In this paper we report a few selected results in Gamma-Ray Astronomy (Crab Nebula and Mrk421 observations, search for high energy tails of Gamma Ray Bursts) and Cosmic Ray Physics (Moon and Sun shadow observations, proton-air cross section measurement, preliminary measurement of the antiproton/proton ratio at TeV energies).

  5. Recent results from the ARGO-YBJ experiment

    SciTech Connect

    Camarri, P.

    2010-03-26

    The ARGO-YBJ experiment at YangBaJing in Tibet (4300 m a.s.l.) has been taking data with its full layout since October 2007. Here we present the first significant results obtained in gamma-ray astronomy and cosmic-ray physics. Emphasis is placed on the analysis of gamma-ray emission from point-like sources (Crab Nebula, MRK 421), on the preliminary limit on the antiproton/proton flux ratio, on the large-scale cosmic-ray anisotropy and on the proton-air cross section. The performance of the detector is also discussed, and the perspectives of the experiment are outlined.

  6. Recent results from the ARGO-YBJ experiment

    NASA Astrophysics Data System (ADS)

    Camarri, P.

    2010-03-01

    The ARGO-YBJ experiment at YangBaJing in Tibet (4300 m a.s.l.) has been taking data with its full layout since October 2007. Here we present the first significant results obtained in gamma-ray astronomy and cosmic-ray physics. Emphasis is placed on the analysis of gamma-ray emission from point-like sources (Crab Nebula, MRK 421), on the preliminary limit on the antiproton/proton flux ratio, on the large-scale cosmic-ray anisotropy and on the proton-air cross section. The performance of the detector is also discussed, and the perspectives of the experiment are outlined.

  7. Physics Division annual report, 1 January-31 December 1984

    SciTech Connect

    Not Available

    1985-10-01

    A brief overview of each of the several areas of research is given with a list of resulting publications. Areas of research include electron-positron annihilation, neutrino interactions, neutrinoless double beta decay of /sup 100/Mo, double beta decay of /sup 76/Ge, antiproton-proton interactions, right-handed gauge boson effects, muon decay asymmetry parameter measurements, supernovae detection, Nemesis search, and detector development. Areas of theoretical research include electroweak interactions, strong interactions, nonperturbative dynamics, supersymmetry, and cosmology and particle physics. 34 figs. (WRF)

  8. Study of resolution of the PANDA GEM detector with Garfield

    NASA Astrophysics Data System (ADS)

    Melnychuk, D.; Voss, B.; Zwieglinski, B.

    2014-05-01

    The forward GEM tracker of the P̅ANDA detector at the future FAIR facility will track the particles produced in antiproton-proton annihilations and emitted in the polar angle range 5∘ -22∘. Position resolution at the level of 100 μ m and good time resolution are critical to work under luminosities up to 2×1032 c m -2 s -1. The simulations performed with Garfield program compared several detector layouts and determined the optimal granularity of readout electronics. The time resolution for two possible gas mixtures was also estimated.

  9. A new calculation of the cosmic-ray antiproton spectrum in the Galaxy and heliospheric modulation effects on this spectrum using a drift plus wavy current sheet model

    NASA Technical Reports Server (NTRS)

    Webber, W. R.; Potgieter, M. S.

    1989-01-01

    The expected interstellar antiproton spectrum arising from cosmic-ray interactions in the Galaxy is recalculated, and the modulation of both antiprotons and protons is calculated using a two-dimensional modulation model incorporating gradient and curvature drifts and a wavy current sheet as well as the usual diffusion, convection, and energy-loss effects. Significant differences in the antiproton/proton ratio for different solar magnetic field polarities are predicted as well as a 'low-energy' component for antiprotons below about 1 GeV.

  10. {barP}ANDA at FAIR

    NASA Astrophysics Data System (ADS)

    Schepers, G.

    The {barP}ANDA experiment represents the central part of the hadron physics branch of the antiproton program of the new Facility for Antiproton and Ion Research (FAIR) at Darmstadt/Germany. It will investigate antiproton annihilations with an almost 4π acceptance from two sequent spectrometer in the momentum range from 1.5 to 15 GeV/c. The gluon rich reaction product of antiproton-proton and antiproton-nucleus collisions on one hand and the high intensity and phase space cooled antiproton beam of the HESR on the other hand constitutes an ideal environment to study the sector of non-conventional hadronic states.

  11. {barP}ANDA at FAIR. Physics and detector

    NASA Astrophysics Data System (ADS)

    Schepers, G.

    2012-12-01

    The {barP}ANDA experiment represents the central part of the hadron physics branch of the antiproton program of the new Facility for Antiproton and Ion Research (FAIR) at Darmstadt/Germany. It will investigate antiproton annihilations with an almost 4 π acceptance from two sequent spectrometer in the momentum range from 1.5 to 15 GeV/c. The gluon rich reaction product of antiproton-proton and antiproton-nucleus collisions on one hand and the high intensity and phase space cooled antiproton beam of the HESR on the other hand constitutes an ideal environment to study the sector of non-conventional hadronic states.

  12. Tracking with Straw Tubes in the barP ANDA Experiment

    NASA Astrophysics Data System (ADS)

    Gianotti, P.; Lucherini, V.; Pace, E.; Kozlov, K.; Ohm, H.; Orfanitski, S.; Mertens, M.; Ritman, J.; Roeder, M.; Serdyuk, V.; Wintz, P.; Ldzik, M.; Przyborowski, D.; Jowzaee, S.; Kajetanowicz, M.; Korcyl, G.; Salabura, P.; Smyrski, J.; Kulessa, P.; Pysz, K.; Boca, G.; Costanza, S.; Lavezzi, L.; Montagna, P.; Rotondi, A.; Savrié, M.; Levitskaya, O.; Kashchuk, A.

    2012-08-01

    Tracking charged particles is one of the essential tasks of the barP ANDA ex periment, providing information about primary and secondary decay vertices, momenta and types of charged particles emitted after antiproton-proton annihilation. Different tracking devices are under construction for the barP ANDA spectrometer and among them the two straw tube trackers. A new technique, based on the use of straw tubes operated at over-pressure has been adopted allowing the construction of self-supporting modules avoiding heavy mechanical frames.

  13. Effects of Uniform Target Density on Random Search

    DTIC Science & Technology

    1987-09-01

    32 1. Description of Difuse Reflection ......................... 32 2. Creating Difluse Reflection Motion ...................... 34 3...IPOSIT (2) SIN (ALPHA) IF (IREFLT .EQ. 0) THEN SDIFFUSE REFLECTING TARGETN CALL DIFUSE (IPOSIT,FPOSIT,IX,PI,TARGET) ELSE SPERFECT OR UNIFORM REFLECTING...DISK TOTDISoTOTDI S*SECANT*VELCT’k IF (IREFLT .EQ. 0) THEN SDIFFUSE REFLECTING TARGET IPOSIT(1 ) FPOSI T(1) IPOSIT(2 ) FFOSI 1(2) CALL DIFUSE (IPOSIT

  14. The BESS Program

    NASA Technical Reports Server (NTRS)

    Mitchell, J. W.; Abe, K.; Anraku, K.; Fuke, H.; Haino, S.; Hams, T.; Imori, M.; Itazaki, A.; Izumi, K.; Kumazawa, T.

    2004-01-01

    In nine flights between 1993 and 2002, the Balloon Borne Experiment with a Superconducting Spectrometer (BESS) has measured the energy spectrum of cosmic-ray antiprotons between 0.18 and 4.20 GeV, and the spectra of protons and helium to several hundred GeV. BESS has also placed stringent upper limits on the existence of antihelium and antiduterons. Above about 1 GeV, models in which antiprotons are secondary products of the interactions of primary cosmic rays with the ISM agree with the BESS spectrum. Below 1 GeV, BESS data suggest the presence of an additional source of antiprotons. The antiproton/proton ratios measured between 1993 and 1999, during the Sun's positive-polarity phase, are consistent with simple models of solar modulation. Results from the 2000 flight, following the solar magnetic field reversal, show a sudden increase in the antiproton/proton ratio and tend to favor a charge-sign-dependent drift model. To extend BESS measurements to lower energies, a new instrument, BESS-Polar, is under construction for a flight from Antarctica in 2004.

  15. Precise Measurements of the Cosmic Ray Antiproton Spectrum with BESS Including the Effects of Solar Modulation

    NASA Technical Reports Server (NTRS)

    Mitchell, J. W.; Abe, K.; Anraku, K.; Asaoka, Y.; Fujikawa, M.; Fuke, H.; Haino, S.; Hams, T.; Ikeda, N.; Imori, M.

    2002-01-01

    The Balloon Borne Experiment with a Superconducting Spectrometer (BESS) has measured the energy spectrum of cosmic-ray antiprotons between 0.18 and 4.20 GeV in eight flights between 1993 and 2002. Above about 1 GeV, models in which antiprotons are secondary products of the interactions of primary cosmic rays with the interstellar gas agree with the BESS antiproton spectrum. Below 1 GeV, the data show a possible excess antiproton flux compared to secondary model predictions, suggesting the presence of an additional source of antiprotons. The antiproton/proton ratios measured between 1993 and 1999, during the Sun's positive-polarity phase, are consistent with simple models of solar modulation. However, results from the 2000 flight, following the solar magnetic field reversal, show a sudden increase in the antiproton/proton ratio and tend to favor a charge-sign-dependent drift model. To extend BESS measurements to lower energies, an evolutionary instrument, BESS-Polar, is under construction for polar flight in 2004.

  16. BESS-Polar II Measurements of the Cosmic-ray Proton and Helium Spectra

    NASA Astrophysics Data System (ADS)

    Sakai, Kenichi

    The energy spectra of cosmic-ray protons and helium near solar minimum were precisely measured with BESS-Polar II (Balloon-borne Experiment with a Superconducting Spectrometer) during a long-duration flight over Antarctica in December 2007 and January 2008. The absolute fluxes and spectral shapes of primary protons and helium probe the origin and the propagation history of cosmic rays in the Galaxy. The spectra are also essential as inputs to calculate the spectrum of cosmic-ray antiprotons, which are secondary products of cosmic-ray interactions with the interstellar gas. To optimize the measurement of the magnetic rigidity of incident particles, obtained from the curvature of their trajectories in a solenoidal magnetic field of 0.8 Tesla, an improved calibration of the central JET-type drift chamber and two inner drift chambers was developed. We report absolute spectra of primary cosmic-ray protons to ˜ 120 GeV and helium to ˜ 50 GeV/nucleon, and compare these to other current measurements. We also report antiproton/proton ratio in the range 0.17 to 3.5 GeV. The temporal variation of the antiproton/proton ratio, measured by BESS since 1993, covering solar minimum, solar maximum, and solar magnetic field reversal, provides a crucial test of charge-sign dependence of solar modulation.

  17. A Neural Network Approach to Model-Based Recognition

    DTIC Science & Technology

    1990-12-26

    unbinarzed pixels of the hologram; t is the er diffusion process.2 The net effect of the error difusion process s to reduce the total quanization error...sinulanon, did come close for both tuipolar and bipolar state values. The resIls with error difusion holorams we r not as good a with pre random

  18. Optimum designs for superpressure balloons

    NASA Astrophysics Data System (ADS)

    Smith, M. S.; Rainwater, E. L.

    2004-01-01

    The elastica shape is now well known to be the best basic shape for superpressure balloon design. This shape, also known as the pumpkin, or natural shape for balloons, has been well understood since the early 1900s when it was applied to the determination of the shape of descending parachutes. The elastica shape was also investigated in the 1950s when high strength films were used to produce superpressure cylinder balloons. The need for uniform stress distribution in shells of early superpressure balloons led to a long period of the development of spherical superpressure balloons. Not until the late 1970s was the elastica shape revisited for the purpose of the producing superpressure balloons. This paper will review various development efforts in the field of superpressure design and will elaborate on the current state-of-the-art with suggestions for future developments.

  19. Evaluation of a Nonlinear Finite Element Program - ABAQUS.

    DTIC Science & Technology

    1983-03-15

    is extracted from a data block in subroutine BELTYP, and then copied onto the buffer area of the short list data ba -.e. Step 3. Read material...problems are relatively complex in terms of their numerical natures. 6.1 An Elastica Elastica is a well-known, classical problem, for which the closed-form...15m~. SCRT CAS)of mo AffiQUS, NlearFinite R EleieAnlss Compusetae Progamii Anlyis CtapabUileity Datesec Strur 20. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Ie At mTRCT Cahw

  20. Initial operation of the Tevatron collider

    SciTech Connect

    Johnson, R.

    1987-03-01

    The Tevatron is now the highest energy proton synchrotron and the only accelerator made with superconducting magnets. Operating since 1983 as a fixed-target machine at energies up to 800 GeV, it has now been modified to operate as a 900 GeV antiproton-proton collider. This paper describes the initial operation of the machine in this mode. The new features of the Fermilab complex, including the antiproton source and the Main Ring injector with its two overpasses and new rf requirements, are discussed. Beam characteristics in the Tevatron (including lifetimes, emittances, luminosity, beam-beam tune shifts, backgrounds, and low beta complications), the coordination of the steps in the accelerator chain, and the commissioning history are also discussed. Finally, some plans for the improvement of the collider are presented.

  1. Experiments on Antiprotons: Antiproton-Nucleon Cross Sections

    DOE R&D Accomplishments Database

    Chamberlain, Owen; Keller, Donald V.; Mermond, Ronald; Segre, Emilio; Steiner, Herbert M.; Ypsilantis, Tom

    1957-07-22

    In this paper experiments are reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured it is possible to obtain an antiproton-proton and an antiproton-deuteron cross section at 457 Mev (lab). Further analysis gives the p-p and p-n cross sections as 104 mb for the p-p reaction cross section and 113 mb for the p-n reaction cross section. The respective annihilation cross sections are 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n cross section by subtraction of the p-p cross section is unfortunately large and somewhat uncertain. The data are compared with the p-p and p-n cross sections and with other results on p-p collisions.

  2. Study of the {chi}{sub 1} and {chi}{sub 2} charmonium states formed in {anti p}p annihilations

    SciTech Connect

    Armstrong, T.A.; Bettoni, D. |; Bharadwaj, V.

    1998-09-01

    The authors report on a study of the {sup 3}P{sub 1}({chi}{sub 1}) and {sup 3}P{sub 2}({chi}{sub 2}) states of charmonium formed in antiproton-proton annihilations. An energy scan through the resonances, performed with a very narrow momentum-band beam of antiprotons intersecting a hydrogen jet target, enables them to perform very precise measurements of the mass and the total width of the two resonances. From their measurement of the quantity {Gamma}(R {r_arrow} {anti p}p) {times} BR(R {r_arrow} J/{psi}{gamma}) {times} BR(J{psi} {r_arrow} e{sup +}e{sup {minus}}), using known branching ratios, the authors obtain: {Gamma}({chi}{sub 1} {r_arrow} {anti p}p) = (69 {+-} 13) eV; {Gamma}({chi}{sub 2} {r_arrow} {anti p}p) = (180 {+-} 31) eV.

  3. Protonium production in ATHENA

    NASA Astrophysics Data System (ADS)

    Venturelli, L.; Amoretti, M.; Amsler, C.; Bonomi, G.; Carraro, C.; Cesar, C. L.; Charlton, M.; Doser, M.; Fontana, A.; Funakoshi, R.; Genova, P.; Hayano, R. S.; Jørgensen, L. V.; Kellerbauer, A.; Lagomarsino, V.; Landua, R.; Rizzini, E. Lodi; Macrì, M.; Madsen, N.; Manuzio, G.; Mitchard, D.; Montagna, P.; Posada, L. G.; Pruys, H.; Regenfus, C.; Rotondi, A.; Testera, G.; van der Werf, D. P.; Variola, A.; Yamazaki, Y.; Zurlo, N.; Athena Collaboration

    2007-08-01

    The ATHENA experiment at CERN, after producing cold antihydrogen atoms for the first time in 2002, has synthesised protonium atoms in vacuum at very low energies. Protonium, i.e. the antiproton-proton bound system, is of interest for testing fundamental physical theories. In the nested penning trap of the ATHENA apparatus protonium has been produced as result of a chemical reaction between an antiproton and the simplest matter molecule, H2+. The formed protonium atoms have kinetic energies in the range 40-700 meV and are metastable with mean lifetimes of the order of 1 μs. Our result shows that it will be possible to start measurements on protonium at low energy antiproton facilities, such as the AD at CERN or FLAIR at GSI.

  4. Single particle momentum and angular distributions in hadron-hadron collisions at ultrahigh energies

    NASA Technical Reports Server (NTRS)

    Chou, T. T.; Chen, N. Y.

    1985-01-01

    The forward-backward charged multiplicity distribution (P n sub F, n sub B) of events in the 540 GeV antiproton-proton collider has been extensively studied by the UA5 Collaboration. It was pointed out that the distribution with respect to n = n sub F + n sub B satisfies approximate KNO scaling and that with respect to Z = n sub F - n sub B is binomial. The geometrical model of hadron-hadron collision interprets the large multiplicity fluctuation as due to the widely different nature of collisions at different impact parameters b. For a single impact parameter b, the collision in the geometrical model should exhibit stochastic behavior. This separation of the stochastic and nonstochastic (KNO) aspects of multiparticle production processes gives conceptually a lucid and attractive picture of such collisions, leading to the concept of partition temperature T sub p and the single particle momentum spectrum to be discussed in detail.

  5. A measurement of the reactions (bar)p/p going to eta/eta, (bar)p/p going to pi(0)/eta and (bar)p/p going to pi(0)/pi(0) from 1.188 GeV/c to 1.445 GeV/c

    NASA Astrophysics Data System (ADS)

    Ritter, Johannes Bruno

    The reactions pp-->hh-->4g,pp-->p 0h-->4g and pp-->p0p 0-->4g were investigated at incident antiproton momenta between 1.188 and 1.445 GeV/c using the Low Energy Antiproton Ring (LEAR) at CERN. This investigation was part of an overall program searching for exotic resonances in antiproton-proton annihilations, focusing on the region near the ξ(2220). Yields for the reactions pp-->hh-->4g,pp-->p 0h-->4g and pp-->p0p 0-->4g are presented as a function of center-of-mass energy over this region. Upper limits are set for the likelihood of the production of the ξ(2220) in these channels based on its non- observation in the data presented.

  6. Measurement of the imaginary part of the I = 1 N-barN S-wave scattering length

    SciTech Connect

    Mutchler, G.S.; Clement, J.; Kruk, J.; Moss, R.; Hungerford, E.; Kishimoto, T.; Mayes, B.; Pinsky, L.; Tang, L.; Xue, Y.; and others

    1988-08-01

    The survival time spectrum of slow antineutrons produced in a liquid-hydrogen target has been measured. From these data the imaginary part of the I = 1 spin-averaged S-wave antineutron proton scattering length has been deduced to be Ima/sub 1/ = -0.83 +- 0.07 fm. The result lies within the range of values calculated from current potential models. In addition, by combining a/sub 1/ with the antiproton-proton scattering length deduced from antiprotonic atoms, the imaginary part of the I = 0 spin-averaged N-barN scattering length was calculated to be Ima/sub 0/ = -1.07 +- 0.16 fm.

  7. FAIR: a Horizon for Future Charming Physics

    SciTech Connect

    Ritman, James

    2007-11-07

    The science goals underlying the future international Facility for Antiproton and Ion Research--FAIR--[1] that is being realized in Darmstadt span a broad range of research activities on the structure of matter. One component of this facility is directed towards studies of hadronic matter at the sub-nuclear level with beams of antiprotons. These studies focus on two key aspects: confinement of quarks and the generation of the hadron masses. These goals will be pursued by performing precision measurements of charged and neutral decay products from antiproton-proton annihilation in the charmonium mass region. In this talk I present some of the issues connected to FAIR in which the groups in Cracow and Juelich are extending and intensifying our cooperation.

  8. Simon van der Meer (1925-2011):. A Modest Genius of Accelerator Science

    NASA Astrophysics Data System (ADS)

    Chohan, Vinod C.

    2011-02-01

    Simon van der Meer was a brilliant scientist and a true giant of accelerator science. His seminal contributions to accelerator science have been essential to this day in our quest for satisfying the demands of modern particle physics. Whether we talk of long base-line neutrino physics or antiproton-proton physics at Fermilab or proton-proton physics at LHC, his techniques and inventions have been a vital part of the modern day successes. Simon van der Meer and Carlo Rubbia were the first CERN scientists to become Nobel laureates in Physics, in 1984. Van der Meer's lesserknown contributions spanned a whole range of subjects in accelerator science, from magnet design to power supply design, beam measurements, slow beam extraction, sophisticated programs and controls.

  9. An Event Building scenario in the trigger-less PANDA experiment

    NASA Astrophysics Data System (ADS)

    Karabowicz, Radoslaw

    2014-06-01

    The PANDA experiment will be running up to 2 × 107 antiproton-proton collisions per second at energies reaching 15 GeV. The lack of simple features distinguishing the interesting events from background, as well as strong pileup of events' data streams make the use of a hardware trigger impossible. As a consequence the whole data stream of about 300 GB/s has to be analyzed online, i.e: tracking, vertex finding, particle identification and event building. The GEM Tracker covers polar angles from 4 to 20 degrees in the forward direction, and can be used for the event building in a large fraction of events. In this work the analysis chain and the implemented algorithms will be presented. Moreover, the event builder prototype based on GEM Tracker data will be presented.

  10. a Precision Comparison of the Proton-Antiproton Charge-To Ratio

    NASA Astrophysics Data System (ADS)

    Phillips, David Forrest

    A new comparison of the antiproton-proton charge -to-mass ratios has been completed. The measured ratio of charge-to-mass ratios for the antiproton and proton is 1.000 000 001 5 +/- 0.000 000 001 1. Comparing the cyclotron frequencies of a single p and p in a Penning tray improves upon the accuracy of earlier techniques by a factor of 45,000. This comparison is the most accurate mass spectroscopy of particles of opposite charge in a Penning trap and the most accurate test of the CPT theorem with baryons. Because of the high precision of the measurement, relativistic shifts in the cyclotron frequency provide a clean demonstration of the "relativistic" mass shift for typical cyclotron energies of 10-100 eV.

  11. The cosmic-ray antiproton spectrum from dark matter annihilation and its astrophysical implications - A new look

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Tylka, A. J.

    1989-01-01

    The spectrum of antiprotons from dark matter annihilation are calculated using the Lund Monte Carlo program, and simple analytic expressions for the spectrum and low-energy antiproton/proton ratio are derived. Comparing the results with recent upper limits on low energy antiprotons, it is concluded that the reported 4-13 GeV antiproton flux cannot be accounted for by dark matter annihilation. The new upper limits do not provide useful constraints on dark matter particles. They restrict the annihilation rate and imply that annihilation gamma ray and e(+) fluxes would be far below the fluxes produced by cosmic-ray collisions. It may be possible to look for a dark matter halo annihilation signal at antiprotons energies below 0.5 GeV, where the flux from cosmic-ray collisions is expected to be negligible.

  12. High Energy Physics at Tufts University. Progress report, 1991--1992

    SciTech Connect

    Not Available

    1992-07-15

    This report discusses the following topics: Neutrino Interactions in the 15-foot Bubble Chamber; Pion and Kaon Production of Charm and Charm-Strange States; Study of Heavy Flavors at the Tagged Particle Spectrometer; Neutrino Oscillations at the Fermilab Main Injector; Soudan II Nucleon Decay Project; Physics at the Antiproton-Proton Collider at {radical}{bar s} = 1.8 TeV; Designing the Solenoidal Detector for the Supercollider; Neutrino Telescope Proposal; Polarization in Inclusive Hyperon Production and QCD Subprocesses; Production and Decay Characteristics of Top Quarks; Scattering in Extended Skyrmion Models and Spin Dependence; Search for Top Quark Production at the Tevatron; Polarization Correlations in Hadronic Production of Top Quarks; and Computation and Networking.

  13. High Energy Physics at Tufts University

    SciTech Connect

    Not Available

    1992-07-15

    This report discusses the following topics: Neutrino Interactions in the 15-foot Bubble Chamber; Pion and Kaon Production of Charm and Charm-Strange States; Study of Heavy Flavors at the Tagged Particle Spectrometer; Neutrino Oscillations at the Fermilab Main Injector; Soudan II Nucleon Decay Project; Physics at the Antiproton-Proton Collider at {radical}{bar s} = 1.8 TeV; Designing the Solenoidal Detector for the Supercollider; Neutrino Telescope Proposal; Polarization in Inclusive Hyperon Production and QCD Subprocesses; Production and Decay Characteristics of Top Quarks; Scattering in Extended Skyrmion Models and Spin Dependence; Search for Top Quark Production at the Tevatron; Polarization Correlations in Hadronic Production of Top Quarks; and Computation and Networking.

  14. Antimatter, a new frontier of science

    SciTech Connect

    Clayton, E.D.

    1988-09-01

    The interest in antimatter arises because antimatter offers such high potential, and it also happens to be the most fascinating of materials. In the discussions that follow, considerations will be made on the potential utilization of antimatter in various applications including: Alternate energy source for rocket propulsion and space missions; Pion-induced fission; Muon-catalyzed cold fusion; and Medicine: in treatment of cancer, and for superior radiographs. Comments also are provided that presently discount antiproton-proton annihilation as a possible source of negative muons in hypothetical hybrid fusion-fission reactors, but this could change in the future. Reasons are given as to why further exploratory work should be undertaken at this time. 42 refs., 7 figs., 3 tabs.

  15. Antiproton-hydrogen atom rearrangement-annihilation cross section

    SciTech Connect

    Morgan, D.L. Jr.

    1986-08-22

    For antiproton energies of several eV or less, annihilation in matter occurs through atomic rearrangement processes in which the antiproton becomes bound to a nucleus prior to annihilation. Existing calculations of the antiproton-hydrogen atom rearrangement cross section are semiclassical and employ the Born-Oppenheimer approximation. They also employ various arguments in regard to the behavior of the system when the Born-Oppenheimer approximation breaks down at small antiproton-proton separations. These arguments indicate that rearrangement is essentially irreversible. In the present study, a detailed investigation was made of the antiproton-hydrogen atom system when the Born-Oppenheimer approximation breaks down. The results of this study indicate that the previous arguments were approximately correct, but that there is a significant probability for rearrangement reversing prior to annihilation. This probability is estimated to be about 20%. 8 refs., 4 figs., 2 tabs.

  16. Study of Excited Ξ Baryons in p̅p-Collisions with the P¯ANDA Detector

    NASA Astrophysics Data System (ADS)

    Pütz, Jennifer; Gillitzer, Albrecht; Ritman, James; Stockmanns, Tobias

    2016-08-01

    Understanding the excitation pattern of baryons is indispensable for the understanding of non-perturbative QCD. Up to now only the nucleon excitation spectrum has been subject to systematic experimental studies, while very little is known on excited states of double or triple strange baryons. In studies of antiproton-proton collisions, the P̅ANDA experiment is well-suited for a comprehensive baryon spectroscopy program in the multi-strange and charm sector. In the present study we focus on excited Ξ- states. For final states containing a Ξ- Ξ̅+ pair, cross sections of the order of μb are expected, corresponding to production rates of ~ 106/d at a luminosity L = 1031 cm-2 s-1. Here we present the reconstruction of the reaction p̅p → Ξ (1820)- Ξ̅+ with Ξ (1820)- → Λ K- and its charged conjugate channel with the P̅ANDA detector.

  17. Reconstructing Hyperons with the ANDA Detector at FAIR

    NASA Astrophysics Data System (ADS)

    Ikegami Andersson, W.

    2016-08-01

    Hyperon production and the study of their properties is an important part of the physics programme of the future ANDA experiment at FAIR. Antihyperon-hyperon pairs will be produced in antiproton-proton collisions through the annihilation of at least one light antiquark-quark (u, d) pair and the creation of a corresponding number of antiquark-quark s pairs. By measuring the decay products of the hyperons, spin observables such as the polarisation can be measured. Many hyperons have a long life-time which gives rise to final state particles originating from displaced vertices. A pattern recognition algorithm using information from the ANDA Straw Tube Tracker is extended to reconstruct not only the transversal, but also the longitudinal components of charged tracks. A Hough transform and a path finding method as tools to extract the longitudinal components are being developed.

  18. The DØ detector

    NASA Astrophysics Data System (ADS)

    Abachi, S.; Abolins, M.; Acharya, B. S.; Adam, I.; Ahn, S.; Aihara, H.; Alvarez, G.; Alves, G. A.; Amos, N.; Anderson, W.; Antipov, Yu.; Aronson, S. H.; Astur, R.; Avery, R. E.; Baden, A.; Balderston, J.; Baldin, B.; Bantly, J.; Barasch, E.; Bartlett, J. F.; Bazizi, K.; Behnke, T.; Bezzubov, V.; Bhat, P. C.; Blazey, G.; Blessing, S.; Boehnlein, A.; Borcherding, F.; Borders, J.; Bozko, N.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoy, V.; Butler, J. M.; Callot, O.; Chakraborty, D.; Chekulaev, S.; Chen, J.; Chen, L.-P.; Chen, W.; Choudhary, B. C.; Christenson, J. H.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Cooper, W. E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M.; Cutts, D.; Dahl, O. I.; Daniels, B.; De, K.; Demarteau, M.; Denisenko, K.; Denisenko, N.; Denisov, D.; Denisov, S.; Dharmaratna, W.; Diehl, H. T.; Diesburg, M.; Dixon, R.; Draper, P.; Ducros, Y.; Durston-Johnson, S.; Eartly, D.; Eberhard, P. H.; Edmunds, D.; Efimov, A.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eroshin, O.; Evdokimov, V.; Fahey, S.; Fanourakis, G.; Fatyga, M.; Featherly, J.; Feher, S.; Fein, D.; Ferbel, T.; Finley, D.; Finocchiaro, G.; Fisk, H. E.; Flattum, E.; Forden, G. E.; Fortner, M.; Franzini, P.; Fuess, S.; Gallas, E.; Gao, C. S.; Geld, T. L.; Genser, K.; Gerber, C. E.; Gibbard, B.; Glebov, V.; Glicenstein, J. F.; Gobbi, B.; Goforth, M.; Good, M. L.; Goozen, F.; Gordon, H.; Graf, N.; Grannis, P. D.; Green, D. R.; Green, J.; Greenlee, H.; Grossman, N.; Grudberg, P.; Guida, J. A.; Guida, J. M.; Guryn, W.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hall, R. E.; Hansen, S.; Hauptman, J.; Hedin, D.; Heinson, A. P.; Heintz, U.; Heuring, T.; Hirosky, R.; Hodel, K.; Hoftun, J. S.; Hubbard, J. R.; Huehn, T.; Huson, R.; Igarashi, S.; Ito, A. S.; James, E.; Jiang, J.; Johns, K.; Johnson, C. R.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jung, C. K.; Kahn, S.; Kanekal, S.; Kernan, A.; Kerth, L.; Kirunin, A.; Klatchko, A.; Klima, B.; Klochkov, B.; Klopfenstein, C.; Klyukhin, V.; Kochetkov, V.; Kohli, J. M.; Kononenko, W.; Kotcher, J.; Kotov, I.; Kourlas, J.; Kozelov, A.; Kozlovsky, E.; Krafczyk, G.; Krempetz, K.; Krishnaswamy, M. R.; Kroon, P.; Krzywdzinski, S.; Kunori, S.; Lami, S.; Landsberg, G.; Lanou, R. E.; Laurens, P.; Lee-Franzini, J.; Li, J.; Li, R.; Li-Demarteau, Q. Z.; Lima, J. G. R.; Linn, S. L.; Linnemann, J.; Lipton, R.; Liu, Y.-C.; Lloyd-Owen, D.; Lobkowicz, F.; Loken, S. C.; Lokos, S.; Lueking, L.; Maciel, A. K. A.; Madaras, R. J.; Madden, R.; Malamud, E.; Mangeot, Ph.; Manning, I.; Mansoulié, B.; Manzella, V.; Mao, H.-S.; Marcin, M.; Markosky, L.; Marshall, T.; Martin, H. J.; Martin, M. I.; Martin, P. S.; Marx, M.; May, B.; Mayorov, A.; McCarthy, R.; McKinley, J.; Mendoza, D.; Meng, X.-C.; Merritt, K. W.; Milder, A.; Mincer, A.; Mondal, N. K.; Montag, M.; Mooney, P.; Mudan, M.; Mulholland, G. T.; Murphy, C.; Murphy, C. T.; Nang, F.; Narain, M.; Narasimham, V. S.; Neal, H. A.; Nemethy, P.; Nešić, D.; Ng, K. K.; Norman, D.; Oesch, L.; Oguri, V.; Oltman, E.; Oshima, N.; Owen, D.; Pang, M.; Para, A.; Park, C. H.; Partridge, R.; Paterno, M.; Peryshkin, A.; Peters, M.; Pi, B.; Piekarz, H.; Pischalnikov, Yu.; Pizzuto, D.; Pluquet, A.; Podstavkov, V.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Que, Y.-K.; Quintas, P. Z.; Rahal-Callot, G.; Raja, R.; Rajagopalan, S.; Rao, M. V. S.; Rasmussen, L.; Read, A. L.; Regan, T.; Repond, S.; Riadovikov, V.; Rijssenbeek, M.; Roe, N. A.; Rubinov, P.; Rutherfoord, J.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Sculli, J.; Selove, W.; Shea, M.; Shkurenkov, A.; Shupe, M.; Singh, J. B.; Sirotenko, V.; Smart, W.; Smith, A.; Smith, D.; Smith, R. P.; Snow, G. R.; Snyder, S.; Sosebee, M.; Souza, M.; Spadafora, A. L.; Stampke, S.; Stephens, R.; Stevenson, M. L.; Stewart, D.; Stocker, F.; Stoyanova, D.; Stredde, H.; Streets, K.; Strovink, M.; Suhanov, A.; Taketani, A.; Tartaglia, M.; Taylor, J. D.; Teiger, J.; Theodosiou, G.; Thompson, J.; Tisserant, S.; Trippe, T. G.; Tuts, P. M.; Van Berg, R.; Vaz, M.; Vishwanath, P. R.; Volkov, A.; Vorobiev, A.; Wahl, H. D.; Wang, D.-C.; Wang, L.-Z.; Weerts, H.; Wenzel, W. A.; White, A.; White, J. T.; Wightman, J.; Willis, S.; Wimpenny, S. J.; Wolf, Z.; Womersley, J.; Wood, D. R.; Xia, Y.; Xiao, D.; Xie, P.; Xu, H.; Yamada, R.; Yamin, P.; Yanagisawa, C.; Yang, J.; Yang, M.-J.; Yoshikawa, C.; Youssef, S.; Yu, J.; Zeller, R.; Zhang, S.; Zhou, Y. H.; Zhu, Q.; Zhu, Y.-S.; Zieminska, D.; Zieminski, A.; Zinchenko, A.; Zylberstejn, A.; DØ Collaboration

    1994-01-01

    The DØ detector is a large general purpose detector for the study of short-distance phenomena in high energy antiproton-proton collisions, now in operation at the Fermilab Tevatron collider. The detector focusses upon the detection of electrons, muons, jets and missing transverse momentum. We describe the design and performance of the major elements of the detector, including the tracking chambers, transition radiation detector, liquid argon calorimetry and muon detection. The associated electronics, triggering systems and data acquisition systems are presented. The global mechanical, high voltage, and experiment monitoring and control systems which support the detector are described. We also discuss the design and implementation of software and software support systems that are specific to DØ.

  19. Aboveground biomass, wood volume, nutrient stocks and leaf litter in novel forests compared to native forests and tree plantations in Puerto Rico

    Treesearch

    A.E. Lugo; O. Abelleira Martínez; J. Fonseca da Silva

    2012-01-01

    The article presents comparative data for aboveground biomass, wood volume, nutirent stocks (N, P, K) and leaf litter in different types of forests in Puerto Rico. The aim of the study is to assess how novel forests of Castilla elastica, Panama Rubber Tree, and Spathodea campanulata, African Tulip Tree, compare with tree plantations and native historical forests (both...

  20. Elastic properties of DNA linked flexible magnetic filaments

    NASA Astrophysics Data System (ADS)

    Ērglis, K.; Zhulenkovs, D.; Sharipo, A.; Cēbers, A.

    2008-05-01

    Elastic properties of magnetic filaments linked by DNA in solutions of univalent and bivalent salts with different pH values are investigated through their deformation in an external field. A strong dependence of the bending modulus in bivalent salt solution on the pH is shown. Experimental results are interpreted on the basis of the magnetic elastica.

  1. Validation of an Acoustic Head Simulator for the Evaluation of Personal Hearing Protection Devices

    DTIC Science & Technology

    2004-11-01

    Difuse -Field Flat Frequency E-A-R...3000 Muff 0 10 20 30 40 50 60 70 80 16 25 40 63 10 0 16 0 25 0 40 0 63 0 10 00 16 00 25 00 40 00 63 00 10 00 0 16 00 0 Difuse -Field Flat Frequency E...10 20 30 40 50 60 70 80 16 25 40 63 10 0 16 0 25 0 40 0 63 0 10 00 16 00 25 00 40 00 63 00 10 00 0 16 00 0 Difuse -Field Flat Frequency E-A-R 3000

  2. Microstructure of Purified Rubber Particles.

    PubMed

    Wood; Cornish

    2000-05-01

    Purified rubber particles from Hevea brasiliensis (Brazilian rubber tree), Parthenium argentatum (guayule), Ficus elastica (Indian rubber tree), and Euphorbia lactiflua were examined and compared using conventional scanning electron microscopy (SEM), field-emission SEM, cryo-SEM, and transmission electron microscopy (TEM). Rubber particles of all four species were spherical; they varied in size and had a uniform homogeneous material, the rubber core, surrounded by a contiguous monolayer (half-unit) membrane. Frozen-hydrated and/or untreated particles from H. brasiliensis and P. argentatum deformed and fused readily, whereas those from F. elastica and E. lactiflua retained their spherical shapes. These results indicate that the surface components of the H. brasiliensis and P. argentatum particles are more fluid than those of F. elastica or E. lactiflua. When fixed in aldehyde, F. elastica particles retained their spherical exterior shapes but had hollow centers, whereas H. brasiliensis and P. argentatum particles completely collapsed. In aldehyde-osmium tetroxide-fixed material, the rubber core of F. elastica was poorly preserved in some particles in which only a small amount of the rubber core remained adhering to the monolayer membrane, leaving a hollow center. Euphorbia lactiflua particles were well preserved in terms of retaining the rubber core; however, the membrane was not as easily discernible as it was in the other three species. Both H. brasiliensis and P. argentatum were well preserved following fixation; their cores remained filled with rubber, and their monolayer membranes were defined. The addition of potassium permanganate to the fixation-staining regime resulted in higher-contrast micrographs and more well defined monolayer membranes.

  3. The mechanical response of woven Kevlar fabric

    SciTech Connect

    Warren, W.E.

    1991-01-01

    Woven Kevlar fabrics exhibit a number of beneficial mechanical properties which include strength, flexibility, and relatively low density. The desire to engineer or design Kevlar fabrics for specific applications has stimulated interest in the development of theoretical models which relate their effective mechanical properties to specific aspects of the fabric morphology and microstructure. In this work the author provides a theoretical investigation of the large deformation elastic response of a plane woven Kevlar fabric and compares these theoretical results with experimental data obtained from uniaxially loaded Kevlar fabrics. The theoretical analysis assumes the woven fabric to be a regular network of orthogonal interlaced yarns and the individual yarns are modeled as extensible elastica, thus coupling stretching and bending effects at the outset. This comparison of experiment with theory indicates that the deformation of woven fabric can be quite accurately predicted by modeling the individual yarns as extensible elastica. 2 refs., 1 fig.

  4. Optimum Designs for Superpressure Balloons

    NASA Astrophysics Data System (ADS)

    Smith, M.; Rainwater, E.

    Natural shape balloons have been employed for minimum stress envelope design in zero pressure scientific balloons since the 1940's. Superpressure balloons, on the other hand, have traditionally been spheres with tangential load attachment points. Application of natural shape design principles to superpressure balloons is relatively new. The resulting natural shape superpressure balloon shape generally fits Euler's Elastica. There are numerous examples of superpressure cylinder balloons which take on the elastica shape when pressurized. Techniques tried for reducing circumferential stresses in the NASA ULDB natural shape superpressure balloons have revealed new challenges both for design and manufacture. This paper will present a thorough background in the development of the current design concept as well as a review of the current challenges associated with manufacturing these envelopes. Approaches for achieving an optimum design will be presented along with ground and flight test data.

  5. On The intrinsic equation behind the Delaunay surfaces

    SciTech Connect

    Mladenov, Ivaielo M.; Hadzhilazova, Mariana Ts.; Djondjorov, Peter A.; Vassilev, Vassil M.

    2008-11-18

    By balancing the internal and external forces acting on axially symmetric membranes one arrives at a system of two equations describing the equilibrium states. This system allows at least two sets of analytical solutions. One of them presents the Euler's elasticas and the other one can be recognized as the class of Delaunay surfaces. The intrinsic equation describing the profile curves of the later is found and solved and this leads to new analytical formulas for these surfaces.

  6. Geometrical Construction of the Hirota Bilinear Form of the Modified Korteweg-De Vries Equation on a Thin Elastic Rod:. Bosonic Classical Theory

    NASA Astrophysics Data System (ADS)

    Matsutani, Shigeki

    Recently there have been several studies of a nonrelativistic elastic rod in R2 whose dynamics is governed by the modified Korteweg-de Vries (MKdV) equation. Goldstein and Petrich found the MKdV hierarchy through its dynamics [Phys. Rev. Lett. 69, 555 (1992).] In this article, we will show the physical meaning of the Hirota bilinear form along the lines of the elastica problem after we formally complexify its arc length.

  7. Variational PDE Models in Image Processing

    DTIC Science & Technology

    2002-07-31

    locate the local or global minima by the gradient descent method. Some of the PDEs can be studied by the viscosity solution approach [24], while many...for smooth functions [31].) This elastica prior model was first studied for inpainting by Masnou and Morel [35], and Chan, Kang, and Shen [11], and...Mumford-Shah inpainting models can be studied in a fashion similar to the classi- cal restoration and segmentation problems. But theoretical study on the

  8. Nonrandom bioelectrical signals in plant tissue.

    PubMed

    Karlsson, L

    1972-06-01

    The results of investigations on nonevoked bioelectrical activity in the India-rubber tree (Ficus elastica) are presented. Metal electrodes inserted into the plant issue were used as the ionic-to-electronic conduction converting elements. Nonevoked pulse bursts were observed with amplitudes in the 10 to 200 microvolts range. An upper limit value of the cell refractory period has been estimated from the maximum pulse frequency observed.

  9. Proceedings of the Army Symposium on Solid Mechanics. Advances in Solid Mechanics for Design and Analysis Held at Newport, Rhode Island on 1-3 October 1984.

    DTIC Science & Technology

    1984-10-01

    to the catenary effect. The concentrated loads on the arch frame were used for non-linear studies wnich are presented later in this paper. 3. PPrYPPF...the structure are r lyqonal frames retered to as arches , and purlins. The present configuration of the TFIPFP involves a framework of extruded...developed in order to treat very large deflections of the arches . This analysis which amounts to a numerical solution of the classical elastica Fq. (3) was

  10. Measurement of the Galactic Cosmic Ray Antiproton Flux from 0.25 GEV to 3.11 GEV with the Isotope Matter Antimatter Experiment (IMAX)

    NASA Astrophysics Data System (ADS)

    Labrador, Allan Wayne

    1997-07-01

    The galactic cosmic ray proton and antiproton abundances were measured with the Isotope Matter Antimatter Experiment (IMAX), a balloon-borne magnet spectrometer. IMAX flew from Lynn Lake, Manitoba, Canada on July 16, 1992. Particles detected by IMAX were identified via the Cherenkov-Rigidity and TOF-Rigidity techniques, with measured mass resolution <=0.2 amu for Z = 1 particles. Previous cosmic ray antiproton experiments reported more antiprotons than expected from high energy cosmic ray interactions with the interstellar medium. IMAX data analysis yielded 124405 protons and 3 antiprotons in the energy range 0.19-0.97 GeV at the instrument, 140617 protons and 8 antiprotons at 0.97-2.58 GeV, and 22524 protons and 5 antiprotons at 2.58-3.08 GeV. These measurements are a statistical improvement over previous measurements, and they demonstrate improved separation of antiprotons from protons, electrons, and other cosmic ray species. When corrected for instrumental and atmospheric background and losses, the ratios at the top of the atmosphere are p/p = 3.21 (+3.49, -1.97)× 10-5 in the energy range 0.25-1.00 GeV, p/p = 5.38 (+3.48, -2.45)× 10-5 at 1.00-2.61 GeV, and p/p = 2.05 (+1.79, -1.15)× 10-4 at 2.61-3.11 GeV. The corresponding antiproton intensities are 2.3 (+2.5, -1.4)× 10-2 (m2 s sr GeV)-1, 2.1 (+1.4, -1.0)× 10-2 (m2 s sr GeV)-1, and 4.3 (+3.7, -2.4)× 10-2 (m2 s sr GeV)-1. The IMAX antiproton fluxes and antiproton/proton ratios are compared with recent Standard Leaky Box Model (SLBM) calculations, in which cosmic ray antiprotons arise solely from high energy cosmic ray interactions with the interstellar medium. Solar modulation effects are also calculated, showing that the antiproton/proton ratio can vary by an order of magnitude over the solar cycle. The IMAX antiproton measurements are consistent with recent calculations of the SLBM and solar modulation. No evidence is found in the IMAX data for excess antiprotons arising from exotic sources. Furthermore

  11. Exclusive Processes in Quantum Chromodynamics

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; Peter Lepage, G.

    The following sections are included: * INTRODUCTION * NONRELATIVISTIC FORM FACTORS FOR HEAVY-QUARK MESONS * HADRONIC WAVEFUNCTIONS * DEFINITIONS * LIGHT-CONE BOUND-STATE EQUATIONS * GENERAL PROPERTIES OF LIGHT-CONE WAVEFUNCTIONS * RENORMALIZATION * CALCULATING * A PERTURBATIVE ANALYSIS * FACTORIZATION—LEADING ORDER ANALYSIS * THE QUARK DISTRIBUTION AMPLITUDE * DETERMINATION OF DISTRIBUTION AMPLITUDES * HIGHER ORDER ANALYSIS * COMPLICATIONS * How LARGE IS ASYMPTOTIC Q? * APPLICATIONS OF QCD TO THE PHENOMENOLOGY OF EXCLUSIVE REACTIONS * GENERAL FEATURES OF EXCLUSIVE PROCESSES IN QCD * ELECTROMAGNETIC FORM FACTORS * COMPARISON OF QCD SCALING WITH EXPERIMENT * EXCLUSIVE ANTI-PROTON PROTON ANNIHILATION PROCESSES * ADDITIONAL TESTS OF GLUON SPIN IN EXCLUSIVE PROCESSES * HADRONIC WAVEFUNCTION PHENOMENOLOGY * CALCULATING TH * THE PRE-QCD DEVELOPMENT OF EXCLUSIVE REACTIONS * EXCLUSIVE e+ e- ANNIHILATION PROCESSES * J/ψ DECAY TO HADRON PAIRS * THE π-ρ PUZZLE * FORM FACTOR ZEROS IN QCD * EXCLUSIVE γγ REACTIONS * QCD PROCESSES IN NUCLEI * EXCLUSIVE NUCLEAR REACTIONS - REDUCED AMPLITUDES * COLOR TRANSPARENCY * SPIN CORRELATIONS IN PROTON-PROTON SCATTERING * CONCLUSIONS * APPENDIX I BARYON FORM FACTORS AND EVOLUTION EQUATIONS * APPENDIX II LIGHT CONE QUANTIZATION AND PERTURBATION THEORY * APPENDIX III A NONPERTURBATIVE ANALYSIS OF EXCLUSIVE REACTIONS-DISCRETIZED LIGHT-CONE QUANTIZATION * ACKNOWLEDGEMENTS * REFERENCES

  12. Bayesian analysis of spatial-dependent cosmic-ray propagation: Astrophysical background of antiprotons and positrons

    NASA Astrophysics Data System (ADS)

    Feng, Jie; Tomassetti, Nicola; Oliva, Alberto

    2016-12-01

    The AMS-02 experiment has reported a new measurement of the antiproton/proton ratio in Galactic cosmic rays (CRs). In the energy range E ˜60 - 450 GeV , this ratio is found to be remarkably constant. Using recent data on CR proton, helium, and carbon fluxes, 10Be/9Be and B/C ratios, we have performed a global Bayesian analysis based on a Markov chain Monte Carlo sampling algorithm under a "two halo model" of CR propagation. In this model, CRs are allowed to experience a different type of diffusion when they propagate in the region close to the Galactic disk. We found that the vertical extent of this region is about 900 pc above and below the disk, and the corresponding diffusion coefficient scales with energy as D ∝E0.15 , describing well the observations on primary CR spectra, secondary/primary ratios, and anisotropy. Under this model, we have carried out improved calculations of antiparticle spectra arising from secondary CR production and their corresponding uncertainties. We made use of Monte Carlo generators and accelerator data to assess the antiproton production cross sections and their uncertainties. While the positron excess requires the contribution of additional unknown sources, we found that the new AMS-02 antiproton data are consistent, within the estimated uncertainties, with our calculations based on secondary production.

  13. A study of two-photon decays of charmonium resonances formed in proton-antiproton annihilations

    NASA Astrophysics Data System (ADS)

    Pedlar, Todd Kristofer

    1999-12-01

    In this dissertation we describe the results of an investigation of the production of charmonium states (hc,h' c,c0and c2) in Fermilab experiment E835 via antiproton-proton annihilation and their detection via their decay into two photons. The hc resonance parameters were determined to be M(hc)=2982.4+2.3- 2.2 MeV, G(hc) =26.9+10.8-9.5 MeV and G(hc-->gg )=5.7+2.9+2.9-2.3- 1.4 keV. For the c2 resonance, a partial width G(c2-->gg )=0.343+0.053+00.43-0.051 -0.038 keV was measured. No evidence in the gg decay mode for either c0 (near s~=3415 MeV) or h'c (in the region s=3575- 3660 = 3575-3660 MeV) regions was found. 90% confidence upper limits were established at G(c0-->gg )<=1.3 keV, and B(h'c-->overline poverlinep)×B(h 'c-->gg) <=5.9×10-8.

  14. Investigation of the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data

    NASA Astrophysics Data System (ADS)

    Giordano, M.; Meggiolaro, E.; Silva, P. V. R. G.

    2017-08-01

    In the present investigation we study the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data. The parametrization used for the hadron-hadron total cross sections at high energy is inspired by recent results obtained by Giordano and Meggiolaro [J. High Energy Phys. 03 (2014) 002, 10.1007/JHEP03(2014)002] using a nonperturbative approach in the framework of QCD, and it reads σtot˜B ln2s +C ln s ln ln s . We critically investigate if B and C can be obtained by means of best-fits to data for proton-proton and antiproton-proton scattering, including recent data obtained at the LHC, and also to data for other meson-baryon and baryon-baryon scattering processes. In particular, following the above-mentioned nonperturbative QCD approach, we also consider fits where the parameters B and C are set to B =κ Bth and C =κ Cth, where Bth and Cth are universal quantities related to the QCD stable spectrum, while κ (treated as an extra free parameter) is related to the asymptotic value of the ratio σel/σtot. Different possible scenarios are then considered and compared.

  15. Production of X(3872) at PANDA

    SciTech Connect

    Chen, G. Y.; Ma, J. P.

    2008-05-01

    The recently discovered X(3872) has many possible interpretations. We study the production of X(3872) with PANDA at GSI for the antiproton-proton collision with two possible interpretations of X(3872). One is as a loosely bound molecule of D mesons, while another is a 2P charmonium state {chi}{sub c1(2P)}. Using effective couplings we are able to give numerical predictions for the production near the threshold and the production associated with {pi}{sup 0}. We also study the possible background near the threshold production for X(3872){yields}J/{psi}{pi}{sup +}{pi}{sup -}. With the designed luminosity 1.5 fb{sup -1} per year of PANDA we find that the event number of pp{yields}J/{psi}{pi}{sup +}{pi}{sup -} near the threshold is at the order of 10{sup 6}-10{sup 8}. Our study shows that two interpretations are distinguishable from the line shape of the production.

  16. The PandaRoot framework for simulation, reconstruction and analysis

    NASA Astrophysics Data System (ADS)

    Spataro, Stefano; PANDA Collaboration

    2011-12-01

    The PANDA experiment at the future facility FAIR will study anti-proton proton and anti-proton nucleus collisions in a beam momentum range from 2 GeV/c up to 15 GeV/c. The PandaRoot framework is part of the FairRoot project, a common software framework for the future FAIR experiments, and is currently used to simulate detector performances and to evaluate different detector concepts. It is based on the packages ROOT and Virtual MonteCarlo with Geant3 and Geant4. Different reconstruction algorithms for tracking and particle identification are under development and optimization, in order to achieve the performance requirements of the experiment. In the central tracker a first track fit is performed using a conformal map transformation based on a helix assumption, then the track is used as input for a Kalman Filter (package genfit), using GEANE as track follower. The track is then correlated to the pid detectors (e.g. Cerenkov detectors, EM Calorimeter or Muon Chambers) to evaluate a global particle identification probability, using a Bayesian approach or multivariate methods. Further implemented packages in PandaRoot are: the analysis tools framework Rho, the kinematic fitter package for vertex and mass constraint fits, and a fast simulation code based upon parametrized detector responses. PandaRoot was also tested on an Alien-based GRID infrastructure. The contribution will report about the status of PandaRoot and show some example results for analysis of physics benchmark channels.

  17. Survival probability of large rapidity gaps in {bar p}p, pp, {gamma}p, and {gamma}{gamma} collisions

    SciTech Connect

    Block, M. M.; Halzen, F.

    2001-06-01

    Using an eikonal analysis, we simultaneously fit a QCD-inspired parametrization of all accelerator data on forward proton-proton and antiproton-proton scattering amplitudes, together with cosmic ray data (using Glauber theory), to predict proton-air and proton-proton cross sections at energies near s{approx}30 TeV. The p-air cosmic ray measurements greatly reduce the errors in the high energy proton-proton and proton-air cross section predictions -- in turn, greatly reducing the errors in the fit parameters. From this analysis, we can then compute the survival probability of rapidity gaps in high energy {bar p}p and pp collisions, with high accuracy in a quasi-model-free environment. Using an additive quark model and vector meson dominance, we note that the survival probabilities are identical, at the same energy, for {gamma}p and {gamma}{gamma} collisions, as well as for nucleon-nucleon collisions. Significantly, our analysis finds large values for gap survival probabilities: {approx}30% at s=200 GeV, {approx}21% at s=1.8 TeV and {approx}13% at s=14 TeV.

  18. Measurement of the elastic, total and diffraction cross sections at tevatron energies

    SciTech Connect

    Belforte, S.; CDF Collaboration

    1993-11-01

    The CDF collaboration has measured the differential elastic cross section d{sigma}{sub el}/dt, the single diffraction dissociation double differential cross section d{sup 2}{sigma}{sub sd}/dM{sup 2}dt and the total inelastic cross section for antiproton-proton collisions at center of mass energies {radical}s = 546 and 1,800 GeV. Data for this measurement have been collected in short dedicated runs during the 1988--1989 data taking period of CDF. The elastic scattering slope is 15.28 {+-} 0.58 (16.98 {+-} 0.25) GeV{sup {minus}2} at {radical}s = 546 (1,800) GeV. Using the luminosity independent method (1 + {rho}{sup 2}){sigma}{sub T} is measured to be 62.64 {+-} 0.95 (81.83 {+-} 2.29) mb at {radical}s = 546 (1,800) GeV. Assuming {rho} = 0.15 the elastic, total and single diffraction cross sections are {sigma}{sub el} = 12.87 {+-} 0.30, {sigma}{sub T} = 61.26 {+-} 0.93 and {sigma}{sub sd} = 7.89 {+-} 0.33 mb ({sigma}{sub el} = 19.70 {+-} 0.85, {sigma}{sub T} = 80.03 {+-} 2.24 and {sigma}{sub sd} = 9.46 {+-} 0.44 mb) at {radical}s = 546 (1,800) GeV.

  19. Triplet based online track finding in the PANDA-STT

    NASA Astrophysics Data System (ADS)

    Mertens, M. C.; Panda Collaboration

    2014-04-01

    The PANDA-Experiment at the future FAIR facility in Darmstadt will study antiproton-proton collisions in a fixed-target setup with a phase-space cooled antiproton beam with a momentum from 1.5 to 15 GeV/c at a nominal interaction rate of 2 · 107 s-1. The data acquisition of the detectors has to run in a triggerless mode and the physics events of interest are identified by an online event filter. Tracking information is a key input for the event filter to distinguish signal events from background. A variety of tracking algorithms is foreseen to process the different track topologies. The so-called Triplet Finder, which is presented here, is a track finding algorithm based on the central straw tube tracker (STT) of PANDA. The algorithm focuses on mathematical simplicity and robustness to allow an online processing of the incoming detector hits. The algorithm and results of a proof-of-concept implementation are presented.

  20. Precision hadron spectroscopy in the charmonium mass region using antiproton annihilation

    SciTech Connect

    Marton, Johann

    2006-11-17

    In contrast to systems at high momentum transfer where high accuracy predictions based on QCD can be made, several essential phenomena are still quantitatively unsettled in strongly interacting systems with low momentum transfer. These phenomena include quark confinement, existence of hadrons other than mesons and baryons, and the generation of the mass of hadrons. Hadronic states provide an intrinsically ideal system to address these issues. In particular, the spectroscopy of states with charm quark content provide a window of opportunity between the chiral and the heavy quark limits. Such states can be produced in copious numbers in antiproton-proton annihilation at the appropriate energy. Beams of antiprotons with unsurpassed brilliance will be available with momenta between 1.5 and 15 GeV/c at the new FAIR facility in Darmstadt, Germany. The combination of stochastic and electron phase space cooling will allow spectroscopy measurements with about 50 keV mass resolution and up to 1032 cm-2s-1 luminosity. These studies will be performed with the PANDA detector that is to be located inside the High Energy Storage Ring. This general purpose detector is a magnetic spectrometer with nearly 4{pi} acceptance for charged and neutral particles. An overview of the physics program and the detector will be presented.

  1. Performance of prototypes for the PANDA barrel EMC

    NASA Astrophysics Data System (ADS)

    Bremer, D. A.; Eissner, T.; Drexler, P.; Moritz, M.; Novotny, R. W.; PANDA Collaboration

    2015-02-01

    The PANDA experiment will be part of the future Facility for Antiproton and Ion Research (FAIR) and aims for the study of strong interaction within the charm sector via antiproton proton collisions up to antiproton momenta of 15 GeV/c. Reflecting the variety of the physics program the PANDA detector is designed as a multi-purpose detector able to perform tracking, calorimetry and particle identification with nearly complete coverage of the solid angle. The Electromagnetic Calorimeter (EMC) contained inside its Target Spectrometer is based on cooled PbWO4 scintillator crystals. In order to ensure an excellent performance throughout the large dynamic range of photon/electron energies ranging from a few MeV up to 15 GeV an extensive prototyping phase is mandatory. This contribution describes the measured response of the EMC barrel part prototype PROTO60 at the largest design energy to secondary beams provided by the SPS at CERN. In addition to PROTO60 a tracking station was deployed, providing precise position information of the 15 GeV/c positrons. For calibration purposes a 150 GeV/c muon beam and cosmic radiation, in combination with estimations from GEANT4 simulations were used. The obtained performance concerning energy, position and time information is presented.

  2. An investigation of the {anti p}p {yields} {anti {Lambda}} {Lambda} and {anti p}p {yields} {anti {Sigma}}{sup 0} {Lambda} + c.c. reactions near threshold

    SciTech Connect

    Tayloe, R.; PS185 Collaboration

    1995-12-31

    Experiment PS 185 studies the production of antihyperon-hyperon pairs in antiproton-proton collisions at LEAR in the near-threshold energy region. The {ital {anti p} p} {r_arrow} {anti {Lambda}}{Lambda} reaction has been thoroughly studied by PS185 and many high-quality data have been reported. New results, including total and differential cross sections along with spin observables, are presented here for the channels {ital {anti p} p} {r_arrow} {anti {Lambda}}{Lambda} and {ital {anti p}p} {r_arrow} {anti {Sigma}}{sup 0}{Lambda} + c.c at incident lab antiproton momenta of 1.726 and 1. 771 GeV/c. The data from the relatively unstudied and complementary {ital {anti p}p} {r_arrow} {anti {Sigma}}{sup 0}{Lambda} + c.c channel is compared to that from {ital {anti p}p} {r_arrow} {anti {Lambda}}{Lambda} at similar energies above the reaction threshold.

  3. Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in anti-p p annihilations

    SciTech Connect

    Andreotti, M.; Bagnasco, S.; Baldini, W.; Bettoni, D.; Borreani, G.; Buzzo, A.; Calabrese, R.; Cester, R.; Cibinetto, G.; Dalpiaz, P.; Garzoglio, G.

    2007-03-01

    We present new precision measurements of the {Psi}(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. It relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. For the {Psi}(2S) meson, by studying the processes {bar p}p {yields} e{sup +}e{sup -} and {bar p}p {yields} J/{Psi} + X {yields} e{sup +}e{sup -} + X, we measure the width {Gamma} = 290 {+-} 25(sta) {+-} 4(sys) keV and the combination of partial widths {Gamma}{sub e{sup +}e{sup -}}{Gamma}{sub {bar p}p}/{Gamma} = 579 {+-} 38(sta) {+-} 36(sys) meV, which represent the most precise measurements to date.

  4. Antiproton-hydrogen atom annihilation. Final report, April-December 1985

    SciTech Connect

    Morgan, D.L.

    1986-05-01

    For antiproton energies of several eV or less, annihilation in matter occurs through atomic rearrangement processes in which the antiproton becomes bound to a nucleus prior to annihilation. Annihilation cross sections via rearrangement at such energies are much higher than for direct antiproton-nucleon annihilation and are, therefore, of consequence to antiproton annihilation propulsion of spacecraft. Existing calculations of the antiproton-hydrogen atom rearrangement cross section are semiclassical and employ the Born-Oppenheimer approximation. They also employ various arguments in regard to the behavior of the system when the Born-Oppenheimer approximation breaks down at small antiproton-proton separations. These arguments indicate that rearrangement is essentially irreversible. In this study, a detailed investigation was made of the antiproton-hydrogen atom system when the Born-Oppenheimer approximation breaks down. Results indicate that the previous arguments were approximately correct, but that there is a significant probability for rearrangement reversing prior to annihilation. This probability is estimated to be about 20%. This consequent reduction in annihilation cross section has little or no negative consequences for antiproton annihilation propulsion at the present time. However, because of the approximate nature of this result and because more-accurate values will be required in the future, it is important to conduct an accurate, fully quantum-mechanical calculation of antiproton-hydrogen atom rearrangement.

  5. Design studies of the PWO Forward End-cap calorimeter for P¯ANDA

    NASA Astrophysics Data System (ADS)

    Moeini, H.; Al-Turany, M.; Babai, M.; Biegun, A.; Bondarenko, O.; Götzen, K.; Kavatsyuk, M.; Lindemulder, M. F.; Löhner, H.; Melnychuk, D.; Messchendorp, J. G.; Smit, H. A. J.; Spataro, S.; Veenstra, R.

    2013-11-01

    The P¯ANDA detection system at FAIR, Germany, is designed to study antiproton-proton annihilations, in order to investigate, among others, the realm of charm-meson states and glueballs, which has still much to reveal. The yet unknown properties of this field are to be unraveled through studying QCD phenomena in the non-perturbative regime. The multipurpose P¯ANDA detector will be capable of tracking, calorimetry, and particle identification, and is planned to run at high luminosities providing average reaction rates up to 2 · 107 interactions/s. The envisaged physics program requires measurements of photons and charged particles with excellent energy, position, and time resolutions. The electromagnetic calorimeter (EMC) will serve as one of the basic components of the detector setup and comprises cooled lead-tungstate (PbWO4) crystals. This paper presents the mechanical design of the Forward End-cap calorimeter and analyzes the response of the Forward End-cap calorimeter in conjunction with the full EMC and the complete P¯ANDA detector. The simulation studies are focused on the performance of the planned EMC with respect to the energy and spatial resolution of the reconstructed photons. Results of the Monte Carlo simulations, excluding very low-energy photons, have been validated by data obtained from a prototype calorimeter and shown to fulfil the requirements imposed by the P¯ANDA physics program.

  6. Measurement of the elastic, total and single diffraction cross sections at Tevatron energies

    SciTech Connect

    Belforte, S.; CDF Collaboration

    1993-11-01

    CDF collaboration has measured the differential elastic cross section d{sigma}{sub el}/dt, the single diffraction dissociation double differential cross section d{sup 2}{sigma}{sub sd}/dM{sup 2}dt and the total inelastic cross section in antiproton-proton collisions at center of mass energies {radical}s=546 and 1800 GeV. The elastic scattering slope is 15.28{plus_minus}0.58 (16.98{plus_minus}0.25) GeV{sup {minus}2} at {radical}s = 546 (1800) GeV. Using the luminosity independent method, (1 + {rho}{sup 2}){sigma}{sub T} is measured to be 62.64{plus_minus}0.95 (81.83{plus_minus}2.29) mb at {radical}s = 546 (1800) GeV. Assuming {rho} = 0.15, the elastic, total and signal diffraction cross sections are {sigma}{sub el} = 12.87{plus_minus}0.30, {sigma}{sub T} = 61.26{plus_minus}0.93 and {sigma}{sub sd} = 7.89{plus_minus}0.33 mb ({sigma}{sub el} = 19.70{plus_minus}0.85, {sigma}{sub T} = 80.03{plus_minus}2.24 and {sigma}{sub sd} = 9.46{plus_minus}0.44 mb) at 546 (1800) GeV.

  7. A reaction-diffusion system modeling the spread of resistance to an antimalarial drug.

    PubMed

    Bacaer, Nicolas; Sokhna, Cheikh

    2005-04-01

    A mathematical model representing the difusion of resistance to an antimalarial drug is developed. Resistance can spread only when the basic reproduction number of the resistant parasites is bigger than the basic reproduction number of the sensitive parasites (which depends on the fraction of infected people treated with the antimalarial drug). Based on a linearization study and on numerical simulations, an expression for the speed at which resistance spreads is conjectured. It depends on the ratio of the two basic reproduction numbers, on a coefficient representing the difusion of mosquitoes, on the death rate of mosquitoes infected by resistant parasites, and on the recovery rate of nonimmune humans infected by resistant parasites.

  8. High-order Spatio-temporal Schemes for Coupled, Multi-physics Reactor Simulations

    SciTech Connect

    Mr. Vijay S. Mahadevan; Dr. Jean C. Ragusa

    2008-09-01

    This report summarizes the work done in the summer of 08 by the Ph.D. student Vijay Mahadevan. The main focus of the work was to coupled 3-D neutron difusion to 3-D heat conduction in parallel with accuracy greater than or equal to 2nd order in space and time. Results show that the goal was attained.

  9. The Biodegradation Characteristics of Proposed Fuel Systems Icing Inhibitors (FSII)

    DTIC Science & Technology

    1996-12-01

    AGAR DIFUSION Toxmcmy TEST................................................................................ 27 IV. RESULTS & ANALYSIS...concentrations, none of the chemicals appeared to inhibit the activity of microorganisms. ix List of Terms Biological Seed - A culture of microorganisms used as...of time to adjust to the presence of a new synthetic chemical, researchers will sometimes attempt to acclimate a culture of microorganisms to a

  10. Stormy Waters: Technology, Sea Control and Regional Warfare

    DTIC Science & Technology

    1994-06-01

    commander’s mind, deterrence may succeed. Today, technological difusion and the proliferation of both advanced conventional weapons and weapons of...planners. The rapidly increasing access to multi-use technologies and a 󈧆Arnett, 2-3. 100 growing scientific and technological culture would appear to

  11. Oxidation Ditch Technology for Upgrading Army Sewage Treatment Facilities.

    DTIC Science & Technology

    1983-08-01

    Science, 1982). 26 - . 1 1 - 1 Difuse Pb i1 __Ah, I Powel CW Diffuser ’-L V. 27 EFFLUENTARIABLE WATER LEVEL Fiur 7 Dagamofoba pan lyot.(Fo R J L C, t/l...construction. Start- TM 5-665 stall and start up? up is easy, but it takes time (weeks--as in any biological process using suspended cultures -- ,, to

  12. Cuyahoga River, Ohio Restoration Study. Third Interim Preliminary Feasibility Report on Erosion and Sedimentation. Supplement.

    DTIC Science & Technology

    1982-06-01

    include studies to identify ind quantify indentifiable (Gully) and difuse (Sheet) nonpoint sources of erosion, and development of management programs...potential critical erosion areas. The development of these OCAP maps is discussed in detail in the PFR. Through the use of USGS cultural features overlay

  13. Relative sensitivity of greenhouse pot plants to long-term exposures of NO- and NO2-containing air.

    PubMed

    Saxe, H

    1994-01-01

    Thirty-five cultivars of pot plants of 20 families were exposed for 50-64 days in a greenhouse facility to either 1 microl litre(-1) NO with 0.5 microl litre(-1) NO2, or 1 microl litre(-1) NO2 with 0.1 microl litre(-1) NO for 15 h each day, with air which was free from these gases as the reference. A sensitivity ranking of the pot plants was compiled, with the highest priority on visible injuries, followed by growth reductions, primarily as a response to the NO-dominated exposures, simulating the NOx-polluted environment in direct-fired, CO2-enriched greenhouses. This treatment reduced the leaf dry weight more than the number and area of the leaves. Twenty-two cultivars were significantly injured, while two (Hibicus sp, Epipremnum pinnatum, green) were significantly improved. The NOx-sensitivity of pot plants was highest in cultivars with variegated, small or narrow leaves, and in the Moraceae family. Nine cultivars (Ficus elastica 'Robusta', F. benjamina, F. pumila 'Sonny', Dieffenbachia maculata 'Camilla', F. elastica 'Tineke', Epipremnum pinnatum 'Marble Queen', Begonia elatior 'Nelson', Cyclamen persica, Poinsettia 'Mini') were specifically sensitive to the NO-containing exposure; six were specifically sensitive to the NO2-containing exposure (F. elastica 'Robusta', Asparagus den. 'Sprengeri', Hedera helix 'Shamrock', Aspledium nidus, Aster novo-belgii, Hypoestes phyl. 'Betina'); and 12 (Soleirolia soleirolii, Asparagus den. 'Sprengeri', H. helix 'Ester', Codiaeum 'Pictum', Rosa 'Minimo Red', F. benjamina 'Starlight', Saintpaulia ionantha 'light blue', F. pumila, Rhododendron simsii, H. helix 'Shamrock', Hibiscus sp., E. pinnatum) were equally sensitive to mixtures dominated by either gas, as measured by at least one response parameter.

  14. Coiling of an elastic beam inside a disk: A model for spider-capture silk

    NASA Astrophysics Data System (ADS)

    Elettro, Hervé; Vollrath, Fritz; Antkowiak, Arnaud; Neukirch, Sébastien

    2015-10-01

    Motivated by recent experimental observations of capillary-induced spooling of fibers inside droplets both in spider capture silk and in synthetic systems, we investigate the behavior of a fiber packed in a drop. Using a simplified 2D model, we provide analytical predictions for the buckling threshold and the deep post-buckling asymptotic behavior. The threshold for spooling is found to be in particularly good agreement with experimental results. We further solve the Elastica equations for a fiber confined in a soft potential, and track the equilibrium paths using numerical continuation techniques. A wealth of different paths corresponding to different symmetries is uncovered, and their stability is finally discussed.

  15. Instant fabrication and selection of folded structures using drop impact

    PubMed Central

    Antkowiak, Arnaud; Audoly, Basile; Josserand, Christophe; Neukirch, Sébastien; Rivetti, Marco

    2011-01-01

    A drop impacting a target cutout in a thin polymer film is wrapped by the film in a dynamic sequence involving both capillary forces and inertia. Different 3D structures can be produced from a given target by slightly varying the impact parameters. A simplified model for a nonlinear dynamic Elastica coupled with a drop successfully explains this shape selection and yields detailed quantitative agreement with experiments. This first venture into the largely unexplored dynamics of elastocapillary assemblies opens up the perspective of mass production of 3D packages with individual shape selection. PMID:21670249

  16. Extraction of glomeruli in whole slide imaging of kidney biopsy specimens

    NASA Astrophysics Data System (ADS)

    Ishikawa, Masahiro; Watanabe, Sumire; Honda, Natsuki; Kobayashi, Naoki; Abe, Tokiya; Hashiguchi, Akinori; Sakamoto, Michiie

    2017-03-01

    The pathological diagnosis of a transplanted kidney is made on Banff Classification in order to gain an accurate understanding of the condition of the kidney. This type of diagnosis is extremely difficult and, thus, a variety of methods for diagnosis, including diagnosis by electron microscope, are being considered at present. Quantification of the diagnostic information derived by image processing is required for such purposes. This study proposes an automatic extraction method for normal glomeruli for the purpose of quantifying Elastica Van Gieson(EVG)-stained pathology specimens. In addition, we provide a report on the package of methods that we have created for the extraction of the glomerulus in the cortex.

  17. Activation and inhibition of rubber transferases by metal cofactors and pyrophosphate substrates.

    PubMed

    Scott, Deborah J; da Costa, Bernardo M T; Espy, Stephanie C; Keasling, Jay D; Cornish, Katrina

    2003-09-01

    Metal cofactors are necessary for the activity of alkylation by prenyl transfer in enzyme-catalyzed reactions. Rubber transferase (RuT, a cis-prenyl transferase) associated with purified rubber particles from Hevea brasiliensis, Parthenium argentatum and Ficus elastica can use magnesium and manganese interchangably to achieve maximum velocity. We define the concentration of activator required for maximum velocity as [A](max). The [A](max)(Mg2+) in F. elastica (100 mM) is 10 times the [A](max)(Mg2+) for either H. brasiliensis (10 mM) or P. argentatum (8 mM). The [A](max)(Mn2+) in F. elastica (11 mM), H. brasiliensis (3.8 mM) and P. argentatum (6.8 mM) and the [A](max)(Mg2+) in H. brasiliensis (10 mM) and P. argentatum (8 mM) are similar. The differences in [A](max)(Mg2+) correlate with the actual endogenous Mg(2+) concentrations in the latex of living plants. Extremely low Mn(2+) levels in vivo indicate that Mg(2+) is the RuT cofactor in living H. brasiliensis and F. elastica trees. Kinetic analyses demonstrate that FPP-Mg(2+) and FPP-Mn(2+) are active substrates for rubber molecule initiation, although free FPP and metal cations, Mg(2+) and Mn(2+), can interact independently at the active site with the following relative dissociation constants K(d)(FPP)

  18. [External fixation of wood as an example of an adapted technic].

    PubMed

    Domres, B; Klöss, T

    1984-01-01

    Logistic reasons gave rise to construction, production and application of an external fixation made of the wood of the rubber-tree (ficus elastica) during the treatment of Cambodian war-injured patients at the field hospital of Khao I Dang. Round pieces of wood 1.5 cm respectively 2 cm in diameter, with drill-holes (diameter 3.2 mm) for the "Steinmann"-nails were planed from well-seasoned planks of the Jang-tree. For the treatment of 25 open fractures - the wooden fixation proved to be the best solution.

  19. Negative post-buckling stiffness of meta-beams

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Overvelde, Johannes; Bertoldi, Katia; van Hecke, Martin

    2014-03-01

    We study the mechanical response of meta-materials whose building blocks undergo buckling. Euler elastica theory describes buckling of slender beams and predicts a positive post-buckling stiffness. Here, we demonstrate experimentally, numerically and theoretically that this limit breaks down when beams become non-slender and that the post-buckling stiffness eventually becomes negative. We further show that the poisson ratio can play the role of an additional design parameter and demonstrate experimentally and numerically that the mechanical response of auxetic meta-beams can indeed become unstable. This paves the way to a new generation of elastic switches, that can be triggered by simple uni-axial experiments.

  20. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Analogies between a Meniscus and a Cantilever

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Lin

    2009-11-01

    Systematic and quantitative analyses of exact analogies between a meniscus and an elastica are performed. It is shown that the two governing equations take the same style after coordinate translation and scale transformation. The morphologies of the liquid bridge and the cantilever are calculated in terms of elliptic integrations, which can be reduced to the same shape after converting the boundary conditions. The present analyses can make us grasp the nature of this physical phenomenon deeply and show some inspiration for designing the analogy experiments. Moreover, the calculated results are helpful to engineering applications, such as design and fabrication of MEMS, and micro-manipulations in micro/nano-technology.

  1. Exploring central opacity and asymptotic scenarios in elastic hadron scattering

    NASA Astrophysics Data System (ADS)

    Fagundes, D. A.; Menon, M. J.; Silva, P. V. R. G.

    2016-02-01

    In the absence of a global description of the experimental data on elastic and soft diffractive scattering from the first principles of QCD, model-independent analyses may provide useful phenomenological insights for the development of the theory in the soft sector. With that in mind, we present an empirical study on the energy dependence of the ratio X between the elastic and total cross sections; a quantity related to the evolution of the hadronic central opacity. The dataset comprises all the experimental information available on proton-proton and antiproton-proton scattering in the c.m. energy interval 5 GeV-8 TeV. Generalizing previous works, we discuss four model-independent analytical parameterizations for X, consisting of sigmoid functions composed with elementary functions of the energy and three distinct asymptotic scenarios: either the standard black disk limit or scenarios above or below that limit. Our two main conclusions are the following: (1) although consistent with the experimental data, the black disk does not represent an unique solution; (2) the data reductions favor a semi-transparent scenario, with asymptotic average value for the ratio X bar = 0.30 ± 0.12. In this case, within the uncertainty, the asymptotic regime may already be reached around 1000 TeV. We present a comparative study of the two scenarios, including predictions for the inelastic channel (diffraction dissociation) and the ratio associated with the total cross-section and the elastic slope. Details on the selection of our empirical ansatz for X and physical aspects related to a change of curvature in this quantity at 80-100 GeV, indicating the beginning of a saturation effect, are also presented and discussed.

  2. Meson Production in Proton-Proton and Antiproton - Interactions at Center of Mass Energy = 24.3 GEV

    NASA Astrophysics Data System (ADS)

    Singh, Vinay Mohan

    Experiment UA6 measured the inclusive production cross section of pi^0, eta, and omega mesons in the p_{T} range 3.5 to 6.1 GeV/c in the reactions;eqalignno {p + p&to M + Xcrnoalign{hbox {rm and}}|{p} + p& to M + Xcr}where M represents a meson and X any other associated particles, at center of mass energy sqrt{s} = 24.3 GeV. The experiment was located at the CERN SppS collider and utilized a fixed hydrogen gas jet as the target in oppositely circulating proton and antiproton beams of momenta 315 GeV/c. The apparatus could be rotated to select either proton-proton or antiproton-proton interactions. The meson production cross section results were obtained from the analysis of 3.7 inverse picobarns (pb ^{-1}) of pp data collected in 1988 and 3.2 pb^{-1} of pp data collected in 1989. The eta/pi ^0 production ratio is measured to be 0.61 +/- 0.03 +/- 0.07 for pp and 0.62 +/- 0.03 +/- 0.07 for pp. The omega/ pi^0 production ratio is measured to be 0.87 +/- 0.16 +/- 0.13 for pp and 0.84 +/- 0.16 +/- 0.13 for pp. The inclusive pi^0 cross section is determined as a function of p_{T} averaged over the rapidity range 0.6 <= y <= 1.2. Comparison of the production between pp and pp reveals no significant difference. The cross section and production ratios are also compared with results from other experiments and found to be in agreement.

  3. Polarization effects in Drell-Yan processes

    NASA Astrophysics Data System (ADS)

    Sissakian, A. N.; Shevchenko, O. Yu.; Nagaitsev, A. P.; Ivanov, O. N.

    2010-01-01

    Effects of polarization of hadrons and constituent quarks in Drell-Yan processes are considered; they are one of the most efficient tools for investigation of the quark structure of hadrons. Special attention is paid to such important parton distribution functions as the transversity and T-odd Sivers and Boer—Mulders functions whose study is necessary for understanding the effects connected with the nonzero transverse component of the quark momentum. An original method for direct extraction of transversity and Boer—Mulders function in the proton from the data on Drell—Yan processes, in which a maximum of one hadron in the initial state is transversely polarized, is presented. This method possesses a number of important advantages. The method is applied both to Drell—Yan processes with a valence antiquark (antiproton-proton and pion-proton collisions) and with a sea antiquark (proton-proton, proton-deuteron, and deuteron-deuteron collisions). Theoretical estimates of asymmetries and cross sections for setups at RHIC (BNL, US), NICA (JINR, Russia), COMPASS (CERN, Switzerland), PAX (GSI, Germany), and J-PARC (Japan) are presented for evaluation of the measurability of transversity and T-odd distributions. These theoretical estimates are accompanied by calculations of statistical uncertainties for measured asymmetries using the new Monte Carlo generator of Drell—Yan events. The duality of Drell—Yan processes and those of production of J/Φ resonance is studied, and it may allow one to considerably reduce statistical uncertainties of parton distributions. Kinematical conditions, for which this duality can be observed, are evaluated.

  4. Does extracellular matrix of the varicose vein wall change according to clinical stage?

    PubMed

    Demirkıran, Mehmet Ali; Köksoy, Cüneyt; Heper, Aylin Okçu; Bengisun, Uğur

    2014-01-01

    The etiology and pathophysiology of chronic venous disease is not fully understood. This study aimed to determine the variation of the extracellular matrix proteins in varicose vein wall according to clinical stage. Forty varicose and 10 control veins were sampled from the saphenofemoral junction. The Clinical Etiologic Anatomic Pathophysiologic (CEAP) classification was used in patients with varicose veins. Samples were stained with hematoxylin-eosin, Masson's trichrome, EVG (Elastica-van Gieson) stain and with laminin, fibronectin, tenascin antibodies. Stained samples were examined immuno-histochemically. Changes in extracellular matrix were determined semi-quantitatively using light microscopy. It was observed that in the early stages (C2-C3) of chronic venous disease, fibrosis is increased in the intima and media layers, with fragmentation in lamina elastica interna, and increased tenascin expression in the intima layer. In advanced stages (C4-C6), the accumulation of tenascin in the intima continued along with fibrosis in the media layer, the thickness of the media layer increased and fibronectin deposition was observed. This study showed that changes first occur in the intima during the early stages of the disease with addition of alterations in the media layer at later stages.

  5. Does extracellular matrix of the varicose vein wall change according to clinical stage?

    PubMed Central

    Demirkıran, Mehmet Ali; Köksoy, Cüneyt; Heper, Aylin Okçu; Bengisun, Uğur

    2014-01-01

    Objective: The etiology and pathophysiology of chronic venous disease is not fully understood. This study aimed to determine the variation of the extracellular matrix proteins in varicose vein wall according to clinical stage. Material and Methods: Forty varicose and 10 control veins were sampled from the saphenofemoral junction. The Clinical Etiologic Anatomic Pathophysiologic (CEAP) classification was used in patients with varicose veins. Samples were stained with hematoxylin-eosin, Masson’s trichrome, EVG (Elastica-van Gieson) stain and with laminin, fibronectin, tenascin antibodies. Stained samples were examined immuno-histochemically. Changes in extracellular matrix were determined semi-quantitatively using light microscopy. Results: It was observed that in the early stages (C2–C3) of chronic venous disease, fibrosis is increased in the intima and media layers, with fragmentation in lamina elastica interna, and increased tenascin expression in the intima layer. In advanced stages (C4–C6), the accumulation of tenascin in the intima continued along with fibrosis in the media layer, the thickness of the media layer increased and fibronectin deposition was observed. Conclusion: This study showed that changes first occur in the intima during the early stages of the disease with addition of alterations in the media layer at later stages. PMID:25931926

  6. The fine structure of developing elastic cartilage.

    PubMed Central

    Cox, R W; Peacock, M A

    1977-01-01

    The fine structure of the elastic cartilage of the pinna has been examined in young rabbits aged from 1 day to 1108 days. Changes associated with growth and development are related not only to age but also to the actual situation in the pinna. In the midline, progressive changes are seen from the tip to the base. The changes in the chondroblasts with time are compared with those described in hyaline cartilage. Structures occur that, except for the presence of crystals, are apparently morphologically identical with the matrix vesicles of calcifying cartilage. These matrix vesicles, however, become very prominent with age, and aggregations of them appear to be released into the intercellular tissue from vacuoles at the periphery of the chondroblasts. There is no obvious association with calcification. Occasional single cilia, desmosomes and giant mitochondria are seen. Elastica is present at birth, and eventually every cell is separated from its neighbours by a partial investment of elastica. The quantity of matrix seems to increase with time, and with distance from the tip of the ear. This is accompanied by a marked increase in cell size with time. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:870470

  7. Theoretical predictions of disclination loop growth for nematic liquid crystals under capillary confinement.

    PubMed

    Shams, Alireza; Yao, Xuxia; Park, Jung Ok; Srinivasarao, Mohan; Rey, Alejandro D

    2014-10-01

    The combination of low elasticity modulus, anisotropy, and responsiveness to external fields drives the rich variety of experimentally observed pattern formation in nematic liquid crystals under capillary confinement. External fields of interest in technology and fundamental physics are flow fields, electromagnetic fields, and surface fields due to confinement. In this paper we present theoretical and simulation studies of the pattern formation of nematic liquid crystal disclination loops under capillary confinement including branching processes from a m=+1 disclination line to two m=+1/2 disclination curves that describe the postnucleation and growth regime of the textural transformation from radial to planar polar textures. The early postnucleation and growth of emerging disclination loops in cylindrical capillaries are characterized using analytical and computational methods based on the nematic elastica that takes into account line tension and line bending stiffness. Using subdiffusive growth and constant loop anisotropy, we found that the solution to the nematic elastica is a cusped elliptical geometry characterized by exponential curvature variations. The scaling laws that govern the loop growth reflect the tension to bending elasticity balance and reveal that the loop dilation rate depends on the curvature and normal velocity of the disclination. The line energy growth is accommodated by the decrease in branch-point curvature. These findings contribute to the evolving understanding of textural transformations in nematic liquid crystals under confinement using the nematic elastic methodology.

  8. Nitrogen recovery from source-separated human urine using clinoptilolite and preliminary results of its use as fertilizer.

    PubMed

    Beler-Baykal, B; Allar, A D; Bayram, S

    2011-01-01

    The use of source separated human urine as fertilizer is one of the major suggestions of the new sanitation concept ECOSAN. Urine is rich in nitrogen, phosphorus and potassium which act as plant nutrients, however its salinity is high for agricultural and landscape purposes. Moreover, characteristics change significantly throughout storage where salinity increases to higher values as the predominant form of nitrogen shifts from urea to ammonium. Transferring nitrogen in human urine onto the natural zeolite clinoptilolite and using the subsequently recovered ammonium from the exhausted clinoptilolite for agricultural/landscape purposes is suggested as an indirect route of using urine in this work. Results reporting the outcome of the proposed process together with characterization of fresh and stored urine, and preliminary work on the application of the product on the landscape plant Ficus elastica are presented. Up to 97% of the ammonium in stored urine could be transferred onto clinoptilolite through ion exchange and about 88% could be recovered subsequently from exhausted clinoptilolite, giving an overall recovery of 86%. Another important merit of the suggested process was the successful elimination of salinity. Preliminary experiments with Ficus elastica had shown that the product, i.e. clinoptilolite exhausted with ammonium, was compatible with the synthetic fertilizer tested.

  9. Modelling population growth with delayed nonlocal reaction in 2-dimensions.

    PubMed

    Liang, Dong; Wu, Jianhong; Zhang, Fan

    2005-01-01

    In this paper, we consider the population growth of a single species living in a two-dimensional spatial domain. New reaction-difusion equation models with delayed nonlocal reaction are developed in two-dimensional bounded domains combining diferent boundary conditions. The important feature of the models is the reflection of the joint efect of the difusion dynamics and the nonlocal maturation delayed efect. We consider and ana- lyze numerical solutions of the mature population dynamics with some wellknown birth functions. In particular, we observe and study the occurrences of asymptotically stable steady state solutions and periodic waves for the two-dimensional problems with nonlocal delayed reaction. We also investigate numerically the efects of various parameters on the period, the peak and the shape of the periodic wave as well as the shape of the asymptotically stable steady state solution.

  10. [Kinetics of in vitro drug release from chitosan and N-alkyl chitosan membranes].

    PubMed

    Li, M; Xin, M; Wang, Q; Yao, K

    2001-03-01

    By using the so-called "lag-time" method, we studied the effect of membrane thickness(h), initial drug concentration(Co) and flow rate(V) on the difusion coefficient(D) of model drug in membranes. The experiment indicates that D increases as h and v increase; D Keeps constant when C0 changes; Under the same condition, the D value of N-alkyl chitosan membrane is bigger than that of pure chitosan membrane.

  11. Gulf Security and the Iran-Iraq War

    DTIC Science & Technology

    1985-01-01

    cultural , reli- gious, economic, and political characteristics and alliances of the region have been further complicated by the Iran-Iraq war and its...weakest Gulf entities, and work toward the difusing of rivalries among the regional states themselves. Obstacles to action, however, included the...weakening the myriad political, commercial, cultural , and educational ties that thus far have bound them closely to the West. Such considerations lead

  12. Investigation of RF Emissions from Electric Field Dominated Plasmas

    DTIC Science & Technology

    1989-03-31

    It originally had been our intention to replace the oil difusion pump with a turbomolecular vacuum pump costing about $5000 before the end of FY 60...serves portion of this inventory is state-of-the-art equip- 25,000 students, and provides the cultural and in- ment of . kind available in few...afternoon and were not carried over into the evenings, which were kept free for such cultural * activities as a string quartet concert, Welsh folk

  13. Radar Sensing of Petroleum Seepage Gases

    DTIC Science & Technology

    1993-01-17

    was difuse and changing from one antenna scan to the next. The ground-based system operators, in searching for candidate returns, settled on three... cultural scatterers. Fig. A-1 I and A-1 2 show two views of the terrain. In Fig. A-1 1 photograph shows a view, looking north, at the mrbile-lab/radar... Cultural scatterers were situated so as to enhance determinations of ranges and bearing, yet did not intrude into the areas of interest. The cultural

  14. Operational Art in Low Intensity Conflict. CLIC PAPERS

    DTIC Science & Technology

    1987-09-01

    critical to US security. Centers of gravity in LIC sittings are more complex and contain inore difuse components which int, ract. Figurc, 3 depicts...America. Mexico is of importance in lines of operation because it serves as a cultural and a geographic link between the US and Latin Am tiecd. in the...contains a culturally unique society with a heritage not fully shared by all people. (37) Because LIC often pits the US against adversaries steeped in

  15. Stepwise enforcement of the notochord and its intersection with the myoseptum: an evolutionary path leading to development of the vertebra?

    PubMed Central

    Grotmol, Sindre; Kryvi, Harald; Keynes, Roger; Krossøy, Christel; Nordvik, Kari; Totland, Geir K

    2006-01-01

    The notochord constitutes the main axial support during the embryonic and larval stages, and the arrangement of collagen fibrils within the notochord sheath is assumed to play a decisive role in determining its functional properties as a fibre-wound hydrostatic skeleton. We have found that during early ontogeny in Atlantic salmon stepwise changes occur in the configuration of the collagen fibre-winding of the notochord sheath. The sheath consists of a basal lamina, a layer of type II collagen, and an elastica externa that delimits the notochord; and these constituents are secreted in a specific order. Initially, the collagen fibrils are circumferentially arranged perpendicular to the longitudinal axis, and this specific spatial fibril configuration is maintained until hatching when the collagen becomes reorganized into distinct layers or lamellae. Within each lamella, fibrils are parallel to each other, forming helices around the longitudinal axis of the notochord, with a tangent angle of 75–80° to the cranio-caudal axis. The helical geometry shifts between adjacent lamellae, forming enantiomorphous left- and right-handed coils, respectively, thus enforcing the sheath. The observed changes in the fibre-winding configuration may reflect adaptation of the notochord to functional demands related to stage in ontogeny. When the vertebral bodies initially form as chordacentra, the collagen lamellae of the sheath in the vertebral region are fixed by the deposition of minerals; in the intervertebral region, however, they represent a pre-adaptation providing torsional stability to the intervertebral joint. Hence, these modifications of the sheath transform the notochord per se into a functional vertebral column. The elastica externa, encasing the notochord, has serrated surfaces, connected inward to the type II collagen of the sheath, and outward to type I collagen of the mesenchymal connective tissue surrounding the notochord. In a similar manner, the collagen matrix of

  16. On random walk de Lévy aplicado aos mapas de variâncias

    NASA Astrophysics Data System (ADS)

    Klafke, J. C.

    2003-08-01

    Uma pergunta que surge ao nos confrontarmos com os mapas de variâncias, ou s-Maps [Klafke, J. C. "Estudo da Difusão Caótica em Ressonâncias Asteroidais", Tese de Doutorado, IAG/USP, 2002] diz respeito ao conteúdo físico de tais representações do espaço de fase. Ou seja, o que representa as variâncias das ações obtidas para uma determinada condição inicial e como relacioná-las com o tempo de difusão das órbitas, supondo-se que estas de fato estejam envolvidas em um processo difusivo? Para discutirmos essa questão, lançamos mão da modelagem dos processos estocásticos subjacentes às variâncias determinadas e implementamos uma série de simulações do tipo Monte Carlo a partir das informações registradas nos s-Maps calculados para algumas ressonâncias asteroidais bem estudadas (p.ex. 3: 1, 2: 1 e 3: 2). Para tanto, temos usado uma função de densidade de probabilidade gaussiana ao definir os n passos que permitirão estabelecer uma relação direta entre o Mapa de Difusão e o Mapa de Variâncias. Contudo, os resultados obtidos até agora tem subestimado o tempo de difusão esperado para os fenômenos conhecidos. Tal se deve ao fato de que, no processo difusivo real, é possível existirem passos de comprimento consideravelmente maiores que a média estabelecida pelas distribuições gaussiana ou normal, sobretudo quando se cruza uma região caótica. Neste trabalho, apresentamos os resultados comparativos de simulações de Monte Carlo com base no random walk de Lévy [Klafter, J. et al. 2002. "Beyond Brownian motion", Phys. Today, Feb, 33-39.], o qual possibilita passos esporádicos de comprimento acima do valor médio (saltos) permitindo estabelecer uma escala de tempo mais próxima da esperada para a difusão.

  17. Postbuckling behaviors of nanorods including the effects of nonlocal elasticity theory and surface stress

    SciTech Connect

    Thongyothee, Chawis Chucheepsakul, Somchai

    2013-12-28

    This paper is concerned with postbuckling behaviors of nanorods subjected to an end concentrated load. One end of the nanorod is clamped while the other end is fixed to a support that can slide in the slot. The governing equation is developed from static equilibrium and geometrical conditions by using the exact curvature corresponding to the elastica theory. The nonlocal elasticity, the effect of surface stress, and their combined effects are taken into account in Euler–Bernoulli beam theory. Differential equations in this problem can be solved numerically by using the shooting-optimization technique for the postbuckling loads and the buckled configurations. The results show that nanorods with the nonlocal elasticity effect undergo increasingly large deformation while the effect of surface stress in combination with nonlocal elasticity decreases the deflection of nanorods under the same postbuckling load.

  18. Slip Morphology of Elastic Strips on Frictional Rigid Substrates

    NASA Astrophysics Data System (ADS)

    Sano, Tomohiko G.; Yamaguchi, Tetsuo; Wada, Hirofumi

    2017-04-01

    The morphology of an elastic strip subject to vertical compressive stress on a frictional rigid substrate is investigated by a combination of theory and experiment. We find a rich variety of morphologies, which—when the bending elasticity dominates over the effect of gravity—are classified into three distinct types of states: pinned, partially slipped, and completely slipped, depending on the magnitude of the vertical strain and the coefficient of static friction. We develop a theory of elastica under mixed clamped-hinged boundary conditions combined with the Coulomb-Amontons friction law and find excellent quantitative agreement with simulations and controlled physical experiments. We also discuss the effect of gravity in order to bridge the difference in the qualitative behaviors of stiff strips and flexible strings or ropes. Our study thus complements recent work on elastic rope coiling and takes a significant step towards establishing a unified understanding of how a thin elastic object interacts vertically with a solid surface.

  19. Equilibria and vibration of a buckled beam with attached masses or spring-mass systems

    NASA Astrophysics Data System (ADS)

    Plaut, Raymond H.; Virgin, Lawrence N.

    2016-09-01

    A buckled beam with immovable pinned ends is considered. Attached to the beam are either one concentrated mass, two concentrated masses, a spring-mass system (that could model a human, robot, or passive vibration absorber), or a horizontal rigid bar with two vertical end springs (a "bounce-pitch" system that could model an animal or a vehicle). In the theoretical analysis, the beam is modeled as an inextensible elastica. Equilibrium configurations are determined first. Then small free vibrations about equilibrium are examined, and the lowest frequencies and corresponding modes are computed. The effects of various parameters are investigated, such as the ratio of the span to the total arc length of the beam, the locations and weights of the attached masses and systems, and the stiffnesses of the springs. For the case of a single attached mass, experiments are conducted and the results are compared to the theoretical ones.

  20. Hencky-type discrete model for pantographic structures: numerical comparison with second gradient continuum models

    NASA Astrophysics Data System (ADS)

    Turco, Emilio; dell'Isola, Francesco; Cazzani, Antonio; Rizzi, Nicola Luigi

    2016-08-01

    Hencky (Über die angenäherte Lösung von Stabilitätsproblemen im Raum mittels der elastischen Gelenkkette. Ph.D. thesis, Engelmann, 1921) proposed a discrete model for elasticae by introducing rigid bars and rotational springs. Hencky (Proc R Soc Lond A Math Phys Eng Sci 472(2185), 2016) approach has been introduced to heuristically motivate the need of second gradient continua. Here, we present a novel numerical code implementing directly the discrete Hencky-type model which is robust enough to solve the problem of the determination of equilibrium configurations in the large deformation and displacement regimes. We apply this model to study some potentially applicable problems, and we compare its performances with those of the second gradient continuum model. The numerical evidence presented supports the conjecture that Hencky-type converges to second gradient model.

  1. Mitochondrial inclusion bodies (intracytoplasmic acidophilic droplets) in neurons of chicken spinal cords increase with age.

    PubMed

    Watanabe, O; Maruo, Y

    2012-03-01

    We studied the pathologic features of neurons that contain intracytoplasmic acidophilic droplets (IADs) in chicken spinal cords. The IADs were lustrous spheroid bodies scattered in the cytoplasm of neurons, variable in size, and protein-rich bodies stained eosinophilic with hematoxylin-eosin, acidophilic with Azan, blue indigo with phosphotungstic acid hematoxylin, and yellow-green with Elastica van Gieson stain histopathologically. Ultrastructurally, almost all IADs were observed as homogeneous highly electron-dense spheroid bodies enclosed by double-limited membranes. Small IADs were observed in mitochondria. Anatomically, IAD-CNs were observed only in the ventral horn of the spinal cord between the fourth sacral and third lumbal vertebrae, and they were particularly frequent in the third sacral vertebrae. Their appearance and accumulative amount were likely to increase with age, while the clinical and pathologic significances of IAD-CNs remain unclear.

  2. Prehistoric polymers: rubber processing in ancient mesoamerica

    PubMed

    Hosler; Burkett; Tarkanian

    1999-06-18

    Ancient Mesoamerican peoples harvested latex from Castilla elastica, processed it using liquid extracted from Ipomoea alba (a species of morning glory vine), and fashioned rubber balls, hollow rubber figurines, and other rubber artifacts from the resulting material. Chemical and mechanical analyses of the latex and of the processed rubber indicate that the enhanced elastic behavior of the rubber relative to the unprocessed latex is due to purification of the polymer component and to an increase in the strength and number of interchain interactions that are induced by organic compounds present in I. alba. These ancient peoples' control over the properties of latex and processed rubber gave rise to the Mesoamerican ball game, a central ritual element in all ancient Mesoamerican societies.

  3. Nonlinear mechanics of a ring structure subjected to multi-pairs of evenly distributed equal radial forces

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Sun, F.; Li, Z. Y.; Taxis, L.; Pugno, N.

    2017-05-01

    Combining the elastica theory, finite element (FE) analysis, and a geometrical topological experiment, we studied the mechanical behavior of a ring subjected to multi-pairs of evenly distributed equal radial forces by looking at its seven distinct states. The results showed that the theoretical predictions of the ring deformation and strain energy matched the FE results very well, and that the ring deformations were comparable to the topological experiment. Moreover, no matter whether the ring was compressed or tensioned by N-pairs of forces, the ring always tended to be regular polygons with 2N sides as the force increased, and a proper compressive force deformed the ring into exquisite flower-like patterns. The present study solves a basic mechanical problem of a ring subjected to lateral forces, which can be useful for studying the relevant mechanical behavior of ring structures from the nano- to the macro-scale.

  4. Mechanical Sensing with Flexible Metallic Nanowires

    NASA Astrophysics Data System (ADS)

    Dobrokhotov, Vladimir; Yazdanpanah, Mehdi; Pabba, Santosh; Safir, Abdelilah; Cohn, Robert

    2008-03-01

    A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire is interpreted to determine the applied force. Using a nanomanipulator the nanowire is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model. In this calibration the elastic modulus was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.

  5. Rubber molecular weight regulation, in vitro, in plant species that produce high and low molecular weights in vivo.

    PubMed

    Cornish, K; Castillón, J; Scott, D J

    2000-01-01

    In three rubber-producing species, in vitro, the rates of initiation and polymerization and the biopolymer molecular weight produced were affected by the concentration of farnesyl diphosphate (FPP) initiator and isopentenyl diphosphate (IPP) elongation substrate (monomer). Ficus elastica, a low molecular weight-producer in vivo, synthesized rubber polymers approximately twice the molecular weight of those made by Hevea brasiliensis or Parthenium argentatum (which produce high molecular weights in vivo), possibly due to its lower IPP Km. In all species, increasing FPP concentrations increased rubber biosynthetic rate and new molecules initiated but decreased molecular weight by competition with the allylic diphosphate (APP) end of elongating rubber molecules for the APP binding site. Increasing IPP concentrations increased rubber biosynthetic rate and rubber molecular weight, but only when FPP concentrations were below the FPP Km's or where negative cooperativity operated. In conclusion, rubber transferase is not the prime regulator of rubber molecular weight in vivo.

  6. Asymptotic self-restabilization of a continuous elastic structure

    NASA Astrophysics Data System (ADS)

    Bosi, F.; Misseroni, D.; Dal Corso, F.; Neukirch, S.; Bigoni, D.

    2016-12-01

    A challenge in soft robotics and soft actuation is the determination of an elastic system that spontaneously recovers its trivial path during postcritical deformation after a bifurcation. The interest in this behavior is that a displacement component spontaneously cycles around a null value, thus producing a cyclic soft mechanism. An example of such a system is theoretically proven through the solution of the elastica and a stability analysis based on dynamic perturbations. It is shown that the asymptotic self-restabilization is driven by the development of a configurational force, of similar nature to the Peach-Koehler interaction between dislocations in crystals, which is derived from the principle of least action. A proof-of-concept prototype of the discovered elastic system is designed, realized, and tested, showing that this innovative behavior can be obtained in a real mechanical apparatus.

  7. Characterization of atherosclerosis by histochemical and immunohistochemical methods in African grey parrots (Psittacus erithacus) and Amazon parrots (Amazona spp.).

    PubMed

    Fricke, Cornelia; Schmidt, Volker; Cramer, Kerstin; Krautwald-Junghanns, Maria-Elisabeth; Dorrestein, Gerry M

    2009-09-01

    The aim of the study was to characterize atherosclerotic changes in African grey parrots (Psittacus erithacus) and Amazon parrots (Amazona spp.) by histochemical and immunohistochemical methods. Samples of the aorta ascendens and trunci brachiocephalici from 62 African grey parrots and 35 Amazon parrots were stained by hematoxylin and eosin and Elastica van Gieson for grading of atherosclerosis in these birds. Four different stages were differentiated. The incidence of atherosclerosis in the examined parrots was 91.9% in African grey parrots and 91.4% in Amazon parrots. To evaluate the pathogenesis in birds, immunohistochemical methods were performed to demonstrate lymphocytes, macrophages, smooth muscle cells, and chondroitin sulfate. According to the missing lymphocytes and macrophages and the absence of invasion and proliferation of smooth muscle cells in each atherosclerotic stage, "response-to-injury hypothesis" seems inapplicable in parrots. Additionally, we found alterations of vitally important organs (heart, lungs) significantly correlated with atherosclerosis of the aorta ascendens.

  8. Geometry in the mechanics of origami

    NASA Astrophysics Data System (ADS)

    Dias, Marcelo A.; Santangelo, Christian D.

    2012-02-01

    We present a mechanical model for curved fold origami in which the bending energies of developable regions are balanced with a phenomenological energy for the crease. The latter energy comes into play as a source of geometric frustration, allowing us to study shape formation by prescribing crease patterns. For a single fold annular configuration, we show how geometry forces a symmetry breaking of the ground state by increasing the width of the ribbon. We extend our model to study multiple fold structures, where we derive geometrical constraints that can be written as recursive relations to build the surface from valley to mountain, and so on. We also suggest a mechanical model for single vertex folds, mapping this problem to an elastica on the sphere.

  9. Use of microwave oven improves morphology and staining of cryostat sections.

    PubMed Central

    Kennedy, A; Foulis, A K

    1989-01-01

    The quality of microscopic image of cryostat sections that had been subjected to microwave assisted fixation was compared with that resulting from conventional air drying of the sections. The role of microwaves in producing rapid special stains on cryostat sections was also assessed. Methods used permitted stains such as periodic acid Schiff, alcian blue, Gordon and Sweets's reticulin, Masson Fontana, Elastica, Prussian blue and Van Gieson to be performed within three minutes of cutting a cryostat section. The cytological detail of nuclei was much clearer using the microwave technique, allowing more accurate determination of cell type. The microwave oven seems to have major potential in improving the diagnostic accuracy of surgical frozen sections. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 PMID:2466053

  10. Fog spontaneously folds mosquito wings

    NASA Astrophysics Data System (ADS)

    Dickerson, Andrew K.; Liu, Xing; Zhu, Ting; Hu, David L.

    2015-02-01

    The flexibility of insect wings confers aerodynamic benefits, but can also present a hazard if exposed to fog or dew. Fog can cause water to accumulate on wings, bending them into tight taco shapes and rendering them useless for flight. In this combined experimental and theoretical study, we use high-speed video to film the spontaneous folding of isolated mosquito wings due to the evaporation of a water drop. We predict shapes of the deformed wing using two-dimensional elastica theory, considering both surface tension and Laplace pressure. We also recommend fold-resistant geometries for the wings of flapping micro-aerial vehicles. Our work reveals the mechanism of insect wing folding and provides a framework for further study of capillarity-driven folding in both natural and biomimetic systems at small scales.

  11. Similarities and differences in rubber biochemistry among plant species.

    PubMed

    Cornish, K

    2001-08-01

    This report reviews aspects of the biochemical regulation of rubber yield and rubber quality in three contrasting rubber-producing species, Hevea brasiliensis, Parthenium argentatum and Ficus elastica. Although many similarities are revealed, considerable differences also exist in enzymatic mechanisms regulating biosynthetic rate and the molecular weight of the rubber biopolymers produced. In all three species, rubber molecule initiation, biosynthetic rate and molecular weight, in vitro, are dependent upon substrate concentration and the ratio of isopentenyl pyrophosphate (IPP, the elongation substrate, or monomer) and farnesyl pyrophosphate (FPP, an initiator), but these parameters are affected by intrinsic properties of the rubber transferases as well. All three rubber transferases are capable of producing a wide range of rubber molecular weight, depending upon substrate concentration, clearly demonstrating that the transferases are not the prime determinants of product size in vivo. However, despite these commonalities, considerable differences exist between the species with respect to cosubstrate effects, binding constants, effective concentration ranges, and the role of negative cooperativity in vitro. The P. argentatum rubber transferase appears to exert more control over the molecular weight it produces than the other two species and may, therefore, provide the best prospect for the source of genes for transformation of annual crop species. The kinetic data, from the three contrasting rubber-producing species, also were used to develop a model of the rubber transferase active site in which, in addition to separate IPP and allylic-PP binding sites, there exists a hydrophobic region that interacts with the linear portion of allylic-PP initiator proximal to the pyrophosphate. Substrate affinity increases until the active site is traversed and the rubber interior of the rubber particle is reached. The kinetic data suggest that the hydrophobic region in H

  12. Variation in nutrient-acquisition patterns by mycorrhizal fungi of rare and common orchids explains diversification in a global biodiversity hotspot

    PubMed Central

    Nurfadilah, Siti; Swarts, Nigel D.; Dixon, Kingsley W.; Lambers, Hans; Merritt, David J.

    2013-01-01

    Background and Aims Many terrestrial orchids have an obligate requirement for mycorrhizal associations to provide nutritional support from germination to establishment. This study will investigate the ability of orchid mycorrhizal fungi (OMF) to utilize a variety of nutrient sources in the nutrient-impoverished (low organic) soils of the Southwest Australian Floristic Region (SWAFR) in order to effectively compete, survive and sustain the orchid host. Methods Mycorrhizal fungi representing key OMF genera were isolated from three common and widespread species: Pterostylis recurva, Caladenia flava and Diuris corymbosa, and one rare and restricted species: Drakaea elastica. The accessibility of specific nutrients was assessed by comparing growth including dry biomass of OMF in vitro on basal CN MMN liquid media. Key Results Each of the OMF accessed and effectively utilized a wide variety of nutrient compounds, including carbon (C) sources, inorganic and organic nitrogen (N) and inorganic and organic phosphorus (P). The nutrient compounds utilized varied between the genera of OMF, most notably sources of N. Conclusions These results suggest that OMF can differentiate between niches (micro-niche specialization) in a constrained, highly resource-limited environment such as the SWAFR. Phosphorus is the most limited macronutrient in SWAFR soils and the ability to access phytate by OMF indicates a characterizing functional capacity of OMF from the SWAFR. Furthermore, compared with OMF isolated from the rare D. elastica, OMF associating with the common P. recurva produced far greater biomass over a wider variety of nutritional sources. This suggests a broader tolerance for habitat variation providing more opportunities for the common orchid for recruitment and establishment at a site. PMID:23532043

  13. Pulmonary Arterial Lesions in New World Camelids in Association With Dicrocoelium dendriticum and Fasciola hepatica Infection.

    PubMed

    Hilbe, M; Robert, N; Pospischil, A; Gerspach, C

    2015-11-01

    In Switzerland, dicrocoeliasis is regarded as the most significant parasitic infection of llamas and alpacas. Fasciola hepatica infestation is also a problem but less common. The aim of the present retrospective study was to evaluate the lungs of New World camelids (NWCs) for evidence of arterial hypertension in association with liver changes due to liver fluke infestation. The lungs of 20 llamas and 20 alpacas with liver fluke infestation were histologically evaluated. The hematoxylin and eosin and van Gieson (VG)-elastica stains as well as immunohistology for the expression of α-smooth muscle actin (α-SMA) were used to visualize the structures of arterial walls. Parasitology of fecal matter (11 llamas and 17 alpacas) confirmed that most of these animals were infested with both Dicrocoelium dendriticum and other gastrointestinal parasites. In most cases (10/12 llamas, 4/6 alpacas), liver enzyme activity in serum was elevated. Histologically, arteries in the lungs of 9 of 20 llamas (45%) and 3 of 20 alpacas (15%) showed severe intimal and adventitial and slight to moderate medial thickening, which was confirmed with α-SMA and VG-elastica staining. All animals exhibited typical liver changes, such as fibrosis and biliary hyperplasia, in association with the presence of liver flukes. This study shows that liver flukes can induce proliferative changes in lung arteries in NWCs that resemble those seen with pulmonary arterial hypertension due to liver parasites in humans. However, the degree of liver fluke infestation was not correlated with the extent of liver damage, or with the amount of thoracic or abdominal effusion or pulmonary arterial changes.

  14. Transportation and Power Requirements for He{sup 3} Mining of the Jovian Planets

    SciTech Connect

    Kammash, Terry; Tang, Ricky

    2008-01-21

    A bi-modal fusion propulsion system that can be used for transportation to and the mining of He{sup 3} from the Jovian planets is proposed. It consists of the Gasdynamic Mirror (GDM) fusion reactor which is analyzed for utilization as a propulsion device, as well as for use as a surface power system. The fusion reactions in the device are initiated by the heating provided by the fission fragments and the annihilation products produced by the 'at rest' annihilation of antiprotons in uranium U{sup 238} target nuclei. The energetic pions and muons of the antiproton-proton (or neutron) annihilation in the U{sup 238} nucleus can heat a suitable fusion fuel to several keV temperature during their short lifetime, while the remaining heating to ignition is provided by the fission fragments. We examine the use of such a system to travel to Jupiter, for instance, to mine the He{sup 3} which is known to exist to the tune of 350 trillion tons in its atmosphere. Such a rich source of this isotope can readily meet the needs of a fusion-powered global industrial energy consumption estimated at 5400 tons annually, for an indefinite length of time. Although He{sup 3} exists to a much lesser degree in the lunar regolith, the power requirements for its extraction, estimated at 270 GJ per kg, may render its economic viability very much in question. It is suggested that mining the planets at a power requirement 30 times less than its lunar counterpart may be more desirable in spite of the distances involved, if a reasonably rapid transportation system can be devised. In its propulsive mode, the GDM device is shown to be capable of traveling to Jupiter and bringing back the annual world need of He{sup 3} in about six months. Based on such performance, it is quite reasonable to envision a space tanker employing the proposed propulsion system to fly from Earth to the outer planet of choice, spend a period of time in the planet's atmosphere extracting He{sup 3}, or loading it from an

  15. Transportation and Power Requirements for He3 Mining of the Jovian Planets

    NASA Astrophysics Data System (ADS)

    Kammash, Terry; Tang, Ricky

    2008-01-01

    A bi-modal fusion propulsion system that can be used for transportation to and the mining of He3 from the Jovian planets is proposed. It consists of the Gasdynamic Mirror (GDM) fusion reactor which is analyzed for utilization as a propulsion device, as well as for use as a surface power system. The fusion reactions in the device are initiated by the heating provided by the fission fragments and the annihilation products produced by the ``at rest'' annihilation of antiprotons in uranium U238 target nuclei. The energetic pions and muons of the antiproton-proton (or neutron) annihilation in the U238 nucleus can heat a suitable fusion fuel to several keV temperature during their short lifetime, while the remaining heating to ignition is provided by the fission fragments. We examine the use of such a system to travel to Jupiter, for instance, to mine the He3 which is known to exist to the tune of 350 trillion tons in its atmosphere. Such a rich source of this isotope can readily meet the needs of a fusion-powered global industrial energy consumption estimated at 5400 tons annually, for an indefinite length of time. Although He3 exists to a much lesser degree in the lunar regolith, the power requirements for its extraction, estimated at 270 GJ per kg, may render its economic viability very much in question. It is suggested that mining the planets at a power requirement 30 times less than its lunar counterpart may be more desirable in spite of the distances involved, if a reasonably rapid transportation system can be devised. In its propulsive mode, the GDM device is shown to be capable of traveling to Jupiter and bringing back the annual world need of He3 in about six months. Based on such performance, it is quite reasonable to envision a space tanker employing the proposed propulsion system to fly from Earth to the outer planet of choice, spend a period of time in the planet's atmosphere extracting He3, or loading it from an extractor plant already in place, and then

  16. Integrated RANS-LES Computations of Turbomachinery Components: Generic Compressor/Diffuser

    NASA Technical Reports Server (NTRS)

    Schlueter, J. U.; Wu, X.; Kim, S.; Alonso, J. J.; Pitsch, H.

    2003-01-01

    The goal of the current study is to apply the coupled RANS-LES approach to a compressor-diffuser geometry of a gas turbine. This flow configuration is important, since the outflow of the compressor alters the flow field in the subsequent diffuser. A detailed knowledge of the flow field in this section allows to optimize the difuser design in order to to achieve a decrease of pressure loss. Here, the NASA stage 35 compressor is coupled with a generic diffuser in order to assess the integrated RANS-LES approach.

  17. Role of thermal diffusion in cw IR laser absorption in gas mixtures.

    PubMed

    Maleissye, J T; Lempereur, F

    1982-01-15

    The absorption of radiation from a cw CO(2) laser by a mixture of absorbing SF(6) and transparent buffer gases has been measured as a function of pressure of added transparent gas (C(4)H(10)). The results are analyzed in terms of thermal diffusion of excited SF6 molecules out of the irradiation zone. In the 60-400-Torr pressure range, thermal difusion depletes the concentration of SF(6) so that the overall absorption is decreased and competes with the various channels of collisional relaxation which enhance absorption. An approximate semiempirical expression is used to determine the transient perturbation of concentration which occurs inside the laser beam.

  18. [Percutaneous permeability study for patches Shangshi Zhitong on different kinds of bases].

    PubMed

    Yan, Xiaoping; Guan, Shijie; Zheng, Rui; Yi, Bowen; Wang, Yonggang; Zhu, Yonghong

    2011-11-01

    To study the percutaneous permeability of patches Shangshi Zhitong on different kinds of bases with the permeation percentage of brucine, strychnine and atropine. Using modified Franz difusion to investigate the penetration quantity of brucine, strychnine and atropine. The contents of brucine, strychnine and atropine were determined by HPLC. The average accumulative permeation percentage of brucine, strychnine and atropine on new base were 53.25%, 74.52% were 34.32%, respectively, and on old base are 54.90%, 50.24%, 46. 54%, respectively. The new base benefits the lipophilic drugs and releases more stably.

  19. Elastoplasticidad anisotropa de metales en grandes deformaciones

    NASA Astrophysics Data System (ADS)

    Caminero Torija, Miguel Angel

    El objetivo de este trabajo es el desarrollo de modelos y algoritmos numericos que simulen el comportamiento del material bajo estas condiciones en el contexto de programas de elementos finitos, dando como resultado predicciones mas precisas de los procesos de conformado y deformacion plastica en general. Para lograr este objetivo se han desarrollado diversas tareas destinadas a mejorar las predicciones en tres aspectos fundamentales. El primer aspecto consiste en la mejora de la descripcion del endurecimiento cinematico anisotropo en pequenas deformaciones, lo cual se ha realizado a traves de modelos y algoritmos implicitos de superficies multiples. Ha sido estudiada la consistencia de este tipo de modelos tanto si estan basados en una regla implicita similar a la de Mroz o en la regla de Prager. Ademas se han simulado los ensayos de Lamba y Sidebottom, obteniendo, en contra de la creencia general, muy buenas predicciones con la regla de Prager. Dichos modelos podrian ser extendidos de forma relativamente facil para considerar grandes deformaciones a traves de procedimientos en deformaciones logaritmicas, similares a los desarrollados en esta tesis y detallados a continuacion. El segundo aspecto consiste en la descripcion de la anisotropia elastoplastica inicial. Esto se ha conseguido mediante el desarrollo de modelos y algoritmos para plasticidad anisotropa en grandes deformaciones, bien ignorando la posible anisotropia elastica, bien considerandola simultaneamente con la anisotropia plastica. Para ello ha sido necesario desarrollar primero un nuevo algoritmo de elastoplasticidad anisotropa en pequenas deformaciones consistentemente linealizado y sin despreciar ningun termino, de tal forma que se conserve la convergencia cuadratica de los metodos de Newton. Este algoritmo en pequenas deformaciones ha servido para realizar la correccion plastica de dos algoritmos en grandes deformaciones. El primero de estos algoritmos es una variacion del clasico algoritmo de

  20. NSLS-II: Nonlinear Model Calibration for Synchrotrons

    SciTech Connect

    Bengtsson, J.

    2010-10-08

    This tech note is essentially a summary of a lecture we delivered to the Acc. Phys. Journal Club Apr, 2010. However, since the estimated accuracy of these methods has been naive and misleading in the field of particle accelerators, i.e., ignores the impact of noise, we will elaborate on this in some detail. A prerequisite for a calibration of the nonlinear Hamiltonian is that the quadratic part has been understood, i.e., that the linear optics for the real accelerator has been calibrated. For synchrotron light source operations, this problem has been solved by the interactive LOCO technique/tool (Linear Optics from Closed Orbits). Before that, in the context of hadron accelerators, it has been done by signal processing of turn-by-turn BPM data. We have outlined how to make a basic calibration of the nonlinear model for synchrotrons. In particular, we have shown how this was done for LEAR, CERN (antiprotons) in the mid-80s. Specifically, our accuracy for frequency estimation was {approx} 1 x 10{sup -5} for 1024 turns (to calibrate the linear optics) and {approx} 1 x 10{sup -4} for 256 turns for tune footprint and betatron spectrum. For a comparison, the estimated tune footprint for stable beam for NSLS-II is {approx}0.1. Since the transverse damping time is {approx}20 msec, i.e., {approx}4,000 turns. There is no fundamental difference for: antiprotons, protons, and electrons in this case. Because the estimated accuracy for these methods in the field of particle accelerators has been naive, i.e., ignoring the impact of noise, we have also derived explicit formula, from first principles, for a quantitative statement. For e.g. N = 256 and 5% noise we obtain {delta}{nu} {approx} 1 x 10{sup -5}. A comparison with the state-of-the-arts in e.g. telecomm and electrical engineering since the 60s is quite revealing. For example, Kalman filter (1960), crucial for the: Ranger, Mariner, and Apollo (including the Lunar Module) missions during the 60s. Or Claude Shannon et al

  1. Study of Cosmic Ray H and He Isotopes

    NASA Astrophysics Data System (ADS)

    Picot-Clemente, Nicolas

    tracer” for antiproton calculations. Current propagation models will be evaluated using already reported antiproton/proton ratios together with the new 2H/1H and 3He/4He ratios. The proposed activities address NASA’s 2010 Science Plan for SMD’s Science Goals in Astrophysics and Heliophysics, specifically with the objectives to “Understand the origin and destiny of the universe, and the nature of black holes, dark energy, dark matter, and gravity” and to “Understand the fundamental physical processes of the space environment from the Sun to Earth, to other planets, and beyond to the interstellar medium”.

  2. Comparison of skin and muscle biopsies before and after pentoxifylline treatment in patients with leg ulcers due to deep venous incompetence.

    PubMed

    Angelides, N S; von der Ahe, C W; Themistocleus, P

    1991-01-01

    The aim of this study was to understand the possible mechanisms by which deep venous insufficiency and venous hypertension are associated with trophic skin changes and ulceration and to explain the therapeutic effect of Pentoxifylline in patients with leg ulcers due to deep venous incompetence. Twenty patients were included in this pilot study. They were graded into two groups: group 1, included 10 patients (5 F and 5 M) with deep venous incompetence and normal arteries; group 2, included 10 patients (1 F and 9 M) with deep venous incompetence and moderate arterial disease. Skin and muscle biopsies were carried out before and after the oral administration of 1,200 mg of Pentoxifylline daily (400 mg t.d.s). The following parameters were investigated by means of light microscopy and immunofluorescence tests: engorgement of venous stroma; decrease of intimal elastica; hyaline degeneration; floccular degeneration; pericapillary fibrin deposits and fibrin degradation products; inflammation and fat necrosis; myofibril degeneration; fibrous scar; regeneration and reconstitution of muscle fibres. The results indicated that local inflammation at the ulcer's area cause accumulation of white blood cells in the capillaries and the interstitial fluid, where there is also accumulation of fibrinogen. These changes may lead to chronic tissue ischaemia and ulceration. The known favourable effect of Pentoxifylline on red cells and leucocyte function as well as its lowering effect on plasma fibrinogen level, may be responsible for the observed therapeutic effect of Pentoxifylline on venous leg ulcers.

  3. A histological, ultrastructural and immunohistochemical study of superficial temporal arteries and middle meningeal arteries in moyamoya disease.

    PubMed

    Li, B; Wang, C C; Zhao, Z Z; Hu, Y; Aihara, K; Ghazizadeh, M; Sasaki, Y; Yang, S Y; Pan, J

    1991-07-01

    Pathologic changes in superficial temporal arteries (STA) and middle meningeal arteries (MMA) biopsied from 15 patients with moyamoya disease (MD) who had undergone cerebro-temporal arterio-synangiosis were studied histologically, ultrastructurally and immunohistochemically. The main pathologic features were: proliferation of smooth muscle cells (SMCs) and thickening of the intima, degeneration and destruction of SMCs in the media and intima, and the presence of condensed organelles in necrosed SMCs or the interstitium among SMCs, or both outside and within the elastica interna (EI). The EI had become thin, porous, fragmented and was even absent in some segments. These changes are different from those of other forms of angiopathy, but identical with those at the ends of internal carotid arteries (ICA) reported by us previously, being pathognomonic for MD. These changes in the STA and MMA reveal that MD involves not only the ICA but also the intra- and extracranial branches of external carotid arteries. The medial necrosis of SMCs seems to be the primary injury of the arterial wall in MD. STA tissue blocks from two cases of MD were stained immunohistochemically. By electron microscopy, IgG-, IgM-, and C3-positive granules were observed on the ER of endothelial and intimal cells. Further studies on more cases are needed to determine whether an immunoreaction has occurred in these arteries.

  4. Buckling of a Flexible Strip Sliding on a Frictional Base

    NASA Astrophysics Data System (ADS)

    Huynen, Alexandre; Marck, Julien; Denoel, Vincent; Detournay, Emmanuel

    2013-03-01

    The main motivation for this contribution is the buckling of a drillstring sliding on the bottom of the horizontal section of borehole. The open questions that remain today are related to the determination of the onset of instability, and to the conditions under which different modes of constrained buckling occur. In this presentation, we are concerned by a two-dimensional version of this problem; namely, the sliding of a flexible strip being fed inside a conduit. The ribbon, which has a flexural rigidity EI and a weight per unit length w, is treated as an inextensible elastica of negligible thickness. The contact between the ribbon and the wall of the conduit is characterized by a friction coefficient μ. First, we report the result of a stability analysis that aims at determining the critical inserted length of the ribbon l* (μ) (scaled by the characteristic length λ =(EI / w) 1 / 3) at which there is separation between the strip and the conduit bottom, as well as the buckling mode. Next, the relationship between the feeding force F and the inserted length l after bifurcation is computed. Finally, the results of a ``kitchen table'' experiment involving a strip of silicon rubber being pushed on a plank are reported and compared with predictions.

  5. Studies on Leaf Venation in Selected Taxa of the Genus Ficus L. (Moraceae) in Peninsular Malaysia.

    PubMed

    Badron, Ummu Hani; Talip, Noraini; Mohamad, Abdul Latiff; Affenddi, Affina Eliya Aznal; Juhari, Amirul Aiman Ahmad

    2014-12-01

    A study on the variation of leaf venation patterns was conducted on 21 taxa of the genus Ficus in Peninsular Malaysia. The results showed the existence of eight leaf venation patterns based on veinlets, the ultimate marginal and areolar venation. The majority of species, such as F. annulata, F. benghalensis, F. benjamina, F. deltoidea var. angustifolia, F. deltoidea var. kunstleri, F. depressa, F. elastica, F. hispida, F. microcarpa, F. religiosa, F. tinctoria, F. ucinata and F. vasculosa, show tri-veinlets. The others exhibit the following: bi-veinlets in F. aurata and F. heteropleura; uni-veinlets in F. lepicarpa, F. schwarzii and F. superba; and simple veinlets in F. aurantiacea and F. fulva. F. sagittata presents no veinlets for areolar venation. The presence of tracheid or swollen veins at the centre of the lamina and the presence of cystolith cells and trichomes are common anatomical characteristics that could assist in group classification of the studied species. Variations in leaf venation patterns are not only valuable in identifying a taxon group, but can also be used to differentiate between species in the genus Ficus.

  6. Studies on Leaf Venation in Selected Taxa of the Genus Ficus L. (Moraceae) in Peninsular Malaysia

    PubMed Central

    Badron, Ummu Hani; Talip, Noraini; Mohamad, Abdul Latiff; Affenddi, Affina Eliya Aznal; Juhari, Amirul Aiman Ahmad

    2014-01-01

    A study on the variation of leaf venation patterns was conducted on 21 taxa of the genus Ficus in Peninsular Malaysia. The results showed the existence of eight leaf venation patterns based on veinlets, the ultimate marginal and areolar venation. The majority of species, such as F. annulata, F. benghalensis, F. benjamina, F. deltoidea var. angustifolia, F. deltoidea var. kunstleri, F. depressa, F. elastica, F. hispida, F. microcarpa, F. religiosa, F. tinctoria, F. ucinata and F. vasculosa, show tri-veinlets. The others exhibit the following: bi-veinlets in F. aurata and F. heteropleura; uni-veinlets in F. lepicarpa, F. schwarzii and F. superba; and simple veinlets in F. aurantiacea and F. fulva. F. sagittata presents no veinlets for areolar venation. The presence of tracheid or swollen veins at the centre of the lamina and the presence of cystolith cells and trichomes are common anatomical characteristics that could assist in group classification of the studied species. Variations in leaf venation patterns are not only valuable in identifying a taxon group, but can also be used to differentiate between species in the genus Ficus. PMID:27073603

  7. [The effect of myocardial bridging on the incidence of coronary arteriosclerosis].

    PubMed

    Lujinović, Almira; Ovcina, Fehim; Cihlarz, Zdenko; Selak, Ivan; Kulenović, Amela

    2006-01-01

    In this paper we dissected 50 human hearts obtained from the Department for Anatomy and Department of Forensic Medicine and Pathology, Faculty of Medicne, Sarajevo. Our interest was to show frequency of myocardial bridging on human heart coronary artery branches, their localisation and dimensions. Cross sections of coronary arteries segments in area of bridges, proximal and distal to it, were taken out from hearts on which dissection method showed presence of myocardial bridging of the coronary artery branches. Cuts were made 5microm-tick and coloured by Hematoxylin-eosine, Elastica Van Giesson, and Ladewig after having been fitted into paraffin wax. Preparations were behold mocroscopically and flow direction of myocardial bridge muscle fibres was followed regarding the artery wall, and it was analysed artery wall structure in the myocardial bridge area, proximal and distal to the bridge. Myocardial bridges werw found in 42% examined cases, and with the most frequent localisation on ramus interventricularis anterior (34%). Atherosclerotic change in the artery segments proximal to the myocardial bridge was detected by the histolopathological method and its intensity depended on the myocardial bridge length and years of age. In the area of the myocardial bridge, besided insignificant diffuse intima, there were not any other histopathological changes that would indicate an atherosclerotic process.

  8. Buckling of a beam extruded into highly viscous fluid

    NASA Astrophysics Data System (ADS)

    Gosselin, F. P.; Neetzow, P.; Paak, M.

    2014-11-01

    Inspired by microscopic Paramecia which use trichocyst extrusion to propel themselves away from thermal aggression, we propose a macroscopic experiment to study the stability of a slender beam extruded in a highly viscous fluid. Piano wires were extruded axially at constant speed in a tank filled with corn syrup. The force necessary to extrude the wire was measured to increase linearly at first until the compressive viscous force causes the wire to buckle. A numerical model, coupling a lengthening elastica formulation with resistive-force theory, predicts a similar behavior. The model is used to study the dynamics at large time when the beam is highly deformed. It is found that at large time, a large deformation regime exists in which the force necessary to extrude the beam at constant speed becomes constant and length independent. With a proper dimensional analysis, the beam can be shown to buckle at a critical length based on the extrusion speed, the bending rigidity, and the dynamic viscosity of the fluid. Hypothesizing that the trichocysts of Paramecia must be sized to maximize their thrust per unit volume as well as avoid buckling instabilities, we predict that their bending rigidity must be about 3 ×10-9N μ m2 . The verification of this prediction is left for future work.

  9. Buckling of a beam extruded into highly viscous fluid.

    PubMed

    Gosselin, F P; Neetzow, P; Paak, M

    2014-11-01

    Inspired by microscopic Paramecia which use trichocyst extrusion to propel themselves away from thermal aggression, we propose a macroscopic experiment to study the stability of a slender beam extruded in a highly viscous fluid. Piano wires were extruded axially at constant speed in a tank filled with corn syrup. The force necessary to extrude the wire was measured to increase linearly at first until the compressive viscous force causes the wire to buckle. A numerical model, coupling a lengthening elastica formulation with resistive-force theory, predicts a similar behavior. The model is used to study the dynamics at large time when the beam is highly deformed. It is found that at large time, a large deformation regime exists in which the force necessary to extrude the beam at constant speed becomes constant and length independent. With a proper dimensional analysis, the beam can be shown to buckle at a critical length based on the extrusion speed, the bending rigidity, and the dynamic viscosity of the fluid. Hypothesizing that the trichocysts of Paramecia must be sized to maximize their thrust per unit volume as well as avoid buckling instabilities, we predict that their bending rigidity must be about 3×10^{-9}Nμm^{2}. The verification of this prediction is left for future work.

  10. A new objective histological scale for studying human photoaged skin.

    PubMed

    Kawabata, K; Kobayashi, M; Kusaka-Kikushima, A; Akasaka, E; Mabuchi, T; Fukui, T; Sugiyama, Y; Takekoshi, S; Miyasaka, M; Ozawa, A; Sakai, S

    2014-05-01

    A quantitative understanding of the histological alteration of the skin is important for assessing the severity of photoaging. We performed Elastica-van Gieson staining and immunohistochemistry for decorin on 34 facial skin sections. We evaluated the alteration of collagen fibers and decorin (a modulator for collagen fibrillogenesis), according to the 5 grades of morphological change in elastic fibers that was established by Kligman (1969). The objectivity of a stage (Stages I-VI), which was established in this study, was evaluated using weighted kappa statistical analysis based on the degree of agreement in stage determination by 11 observers using a blind procedure. Correlation between the crow's-feet-area wrinkles grades of another 26 women and stages was also analyzed. The initial alteration of elastic fibers was observed in the deep dermis. Decorin was not detected in very severely altered skin. Based on the combination of changes in the elastic fibers, collagenic fibers, and decorin, skin tissues were categorized into 6 stages according to severity. The statistical analysis showed almost perfect agreement between observers. Significant positive correlation between stages and wrinkle scores was found. We propose a new objective histological scale that is useful for assessing the severity of photoaging. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Self-encapsulation, or the ‘dripping’ of an elastic rod

    PubMed Central

    Bosi, F.; Misseroni, D.; Dal Corso, F.; Bigoni, D.

    2015-01-01

    A rod covering a fixed span is loaded at the middle with a transverse force, such that with increasing load a progressive deflection occurs. After a certain initial deflection, a phenomenon is observed where two points of the rod come in contact with each other. This is defined as the ‘dripping point’ and is when ‘self-encapsulation’ of the elastic rod occurs. Dripping seems at a first glance to be impossible and definitely cannot occur in the presence of ‘ordinary’ constraints (such as simple supports or clamps) at the ends of the span. However, the elastica governs oscillating pendulums, buckling rods and pendant drops, so that a possibility for self-encapsulation might be imagined. This phenomenon is indeed demonstrated (both theoretically and experimentally) to occur when at least one of the constraints at the ends of the rod is a sliding sleeve. This mechanical device generates a configurational force, causing the dripping of the rod, in a fully elastic set-up. PMID:26346447

  12. Reconfiguration of a flexible flat plate under snow loading

    NASA Astrophysics Data System (ADS)

    Gosselin, Frédérick; de Langre, Emmanuel

    2015-11-01

    Snow and wind constitute two of the main sources of mechanical loading on terrestrial plants. Plants bend and twist with large amplitude to bear these loads. For the past ten years, various authors have sought to decompose the problem of plant reconfiguration under fluid flow into its fundamental mechanical ingredients by studying the reconfiguration of simple flexible structures such as beams, plates, rods and strips. Here, we adopt a similar approach to these studies and consider the snow interception of a flexible flat plate. We performed two sets of experiments on thin flexible rectangular plates supported at their center: in the first one, a plate was subjected to real snowing events; in the second one, a plate was loaded with glass beads acting as a granular media similar to snow. Moreover, a theoretical model coupling the Elastica formulation to a loading with a set angle of repose is developed. The model is found to be in good agreement with the experiments on glass beads. Asymptotic scaling laws can be found similarly to the Vogel exponents of reconfiguring structures. For the real snow loading, it is found that the cohesive force in snow which is highly dependent on the snow temperature complicate things greatly.

  13. Three-dimensional analysis of alveolar wall destruction in the early stage of pulmonary emphysema.

    PubMed

    Kobayashi, Yukihiro; Uehara, Takeshi; Kawasaki, Kenji; Sugano, Mitsutoshi; Matsumoto, Takehisa; Matsumoto, Gou; Honda, Takayuki

    2015-03-01

    The morphological mechanism of alveolar wall destruction during pulmonary emphysema has not been clarified. The aim of this study was to elucidate this process three-dimensionally. Lung specimens from five patients with pulmonary emphysema were used, and five controls with normal alveolar structure were also examined. Sections 150 μm thick were stained with hematoxylin and eosin, elastica, and silver impregnation, and immunostained with selected antibodies. We examined these sections three-dimensionally using a laser confocal microscope and a light microscope. There were only a few Kohn's pores and no fenestrae in the normal alveoli from the controls. In the lungs of the emphysema patients a small rupture appeared in the extremely thin alveolar wall among the alveolar capillaries. This rupture enlarged to form a circle surrounded by the capillaries, which was called an alveolar fenestra. Two neighboring fenestrae fused by breakdown of the collapsed or cord-like capillary between them to form a large fenestra. The large fenestrae fused repeatedly to become larger, and these were bordered by thick elastic fibers constructing an alveolar framework. Alveolar wall destruction during emphysema could start from small ruptures of the alveolar wall that become fenestrae surrounded by capillaries, which fuse repeatedly to become larger fenestrae rimmed with elastic fibers. The alveolar capillary network could initially prevent enlargement of the fenestrae, and the thick elastic fibers constituting the alveolar framework could secondarily prevent destruction of the alveolar wall structure.

  14. Micro-mechanical model for the tension-stabilized enzymatic degradation of collagen tissues

    NASA Astrophysics Data System (ADS)

    Nguyen, Thao; Ruberti, Jeffery

    We present a study of how the collagen fiber structure influences the enzymatic degradation of collagen tissues. Experiments of collagen fibrils and tissues show that mechanical tension can slow and halt enzymatic degradation. Tissue-level experiments also show that degradation rate is minimum at a stretch level coincident with the onset of strain-stiffening in the stress response. To understand these phenomena, we developed a micro-mechanical model of a fibrous collagen tissue undergoing enzymatic degradation. Collagen fibers are described as sinusoidal elastica beams, and the tissue is described as a distribution of fibers. We assumed that the degradation reaction is inhibited by the axial strain energy of the crimped collagen fibers. The degradation rate law was calibrated to experiments on isolated single fibrils from bovine sclera. The fiber crimp and properties were fit to uniaxial tension tests of tissue strips. The fibril-level kinetic and tissue-level structural parameters were used to predict tissue-level degradation-induced creep rate under a constant applied force. We showed that we could accurately predict the degradation-induce creep rate of the pericardium and cornea once we accounted for differences in the fiber crimp structure and properties.

  15. A Histoenzymatic Study of Human Intracranial Atherosclerosis

    PubMed Central

    Hoff, Henry F.

    1972-01-01

    A light microscopy study on the localization of enzyme activity within atherosclerotic human intracranial arteries was performed on autopsy material obtained within 4 hours of death. The data suggests that the atherosclerotic process first goes through a proliferative phase and then a degenerative phase culminating in the formation of a plaque. In the proliferative phase, smooth muscle cell proliferation has formed a thickened intima. Tetrazolium reductase, adenosine triphosphatase (ATPase) and adenosine monophosphatase (AMPase) activities are present in these cells, while all dehydrogenases and acid phosphatase activities were weak or not present. As the degenerative phase commences, an area of necrosis, lipid and macrophage accumulation is formed on the lumen side of the elastica. This area increases in size until a plaque is formed. Unsaturated polar and nonpolar lipid, cholesterol, α-glycerophosphate dehydrogenase, acid phosphatase, and AMPase activities are associated with these areas and in foam cells, which are often found in the thickened intima of the proliferative phase. Tetrazolium reductase and ATPase activities decrease in the thickened intima as the area of necrosis increases in size, while dehydrogenase activity, except that for α-glycerophosphate, remains low or not present. Patterns of enzyme alterations for various stages of the disease process in intracranial arteries, the aorta and coronary arteries suggest a similar, if not identical, progression of the atherosclerotic process, irrespective of known differences in the prevalence of atherosclerosis. ImagesFig 2Fig 3Fig 5Fig 1Fig 4 PMID:4260721

  16. Combined Euler column vibration isolation and energy harvesting

    NASA Astrophysics Data System (ADS)

    Davis, R. B.; McDowell, M. D.

    2017-05-01

    A new device that combines vibration isolation and energy harvesting is modeled, simulated, and tested. The vibration isolating portion of the device uses post-buckled beams as its spring elements. Piezoelectric film is applied to the beams to harvest energy from their dynamic flexure. The entire device operates passively on applied base excitation and requires no external power or control system. The structural system is modeled using the elastica, and the structural response is applied as forcing on the electric circuit equation to predict the output voltage and the corresponding harvested power. The vibration isolation and energy harvesting performance is simulated across a large parameter space and the modeling approach is validated with experimental results. Experimental transmissibilities of 2% and harvested power levels of 0.36 μW are simultaneously demonstrated. Both theoretical and experimental data suggest that there is not necessarily a trade-off between vibration isolation and harvested power. That is, within the practical operational range of the device, improved vibration isolation will be accompanied by an increase in the harvested power as the forcing frequency is increased.

  17. Histological characteristics of the abdominal aortic wall in patients with vascular chronic Q fever

    PubMed Central

    Hagenaars, Julia C J P; Koning, Olivier H J; van den Haak, Ronald F F; Verhoeven, Bart A N; Renders, Nicole H M; Hermans, Mirjam H A; Wever, Peter C; van Suylen, Robert Jan

    2014-01-01

    The aim of this study was to describe specific histological findings of the Coxiella burnetii-infected aneurysmal abdominal aortic wall. Tissue samples of the aneurysmal abdominal aortic wall from seven patients with chronic Q fever and 15 patients without evidence of Q fever infection were analysed and compared. Chronic Q fever was diagnosed using serology and tissue PCR analysis. Histological sections were stained using haematoxylin and eosin staining, Elastica van Gieson staining and immunohistochemical staining for macrophages (CD68), T lymphocytes (CD3), T lymphocyte subsets (CD4 and CD8) and B lymphocytes (CD20). Samples were scored by one pathologist, blinded for Q fever status, using a standard score form. Seven tissue samples from patients with chronic Q fever and 15 tissue samples from patients without Q fever were collected. Four of seven chronic Q fever samples showed a necrotizing granulomatous response of the vascular wall, which was characterized by necrotic core of the arteriosclerotic plaque (P = 0.005) and a presence of high numbers of macrophages in the adventitia (P = 0.007) distributed in typical palisading formation (P = 0.005) and surrounded by the presence of high numbers of T lymphocytes located diffusely in media and adventitia. Necrotizing granulomas are a histological finding in the C. burnetii-infected aneurysmal abdominal aortic wall. Chronic Q fever should be included in the list of infectious diseases with necrotizing granulomatous response, such as tuberculosis, cat scratch disease and syphilis. PMID:24953727

  18. Damage from periorbital ageing to the multilayered structures and resilience of the skin in Chinese population

    PubMed Central

    Liao, Chuh-Kai; Tsai, Feng-Chou; Fong, Tsorng-Harn; Hu, Chien-Ming; Wei, Po-Li; Su, Ching-Hua

    2013-01-01

    Ageing dynamically disrupts the multilayered supporting components of the skin that are held together by cell adhesion molecules (CAMs). Skin specimens from 33 female Chinese patients undergoing lower blepharoplasty were divided into three age groups and examined by haematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) and Elastica-van Gieson (EVG) stains, western blotting, surface electron microscopy (SEM) and biomechanical tension analysis. The SEM density (skin surface topology) showed a negative linear relationship with age. The triangular pattern of the skin surface in the younger group gradually broke down into quadrangular and irregular patterns in the older group. Collagens and elastic fibres in the dermis showed anisotropy and decreased density in the older groups compared with the younger group, especially in the papillary dermis. Anisotropy means that physical properties differ according to the direction of measurement. E-cadherin and integrin αv (whose functions are to bind epidermal and dermal elements respectively) increased and decreased, respectively, in the oldest group. Skin resilience decreased significantly in this group under repetitive stress. In conclusion, a loss of skin surface textures, integrin αv expressions, epidermal-dermal connections and dermal compactness led to the multilayered structure of the skin becoming separated. This in turn decreased resilience during ageing. These findings may therefore explain why aged skins cannot tolerate repetitive facial expressions, and why this action produces further dynamic wrinkles. PMID:23441675

  19. Micromechanics of collective buckling in CNT turfs

    NASA Astrophysics Data System (ADS)

    Torabi, Hamid; Radhakrishnan, Harish; Mesarovic, Sinisa Dj.

    2014-12-01

    Complex structures consisting of intertwined, nominally vertical carbon nanotubes (CNTs) are called turfs. Under uniform compression experiments, CNT turfs exhibit irreversible collective buckling of a layer preceded by reorientation of CNT segments. Experimentally observed independence of the buckling stress and the buckling wavelength on the turf width suggests the existence of an intrinsic material length. To investigate the relationship the macroscopic material properties and the statistical parameters describing the nano-scale geometry of the turf (tortuosity, density and connectivity) we develop a nano-scale computational model, based on the representation of CNT segments as elastica finite elements with van der Waals interactions. The virtual turfs are generated by means of a constrained random walk algorithm and subsequent relaxation. The resulting computational model is robust and is capable of modeling the collective behavior of CNTs. We first establish the dependence of statistical parameters on the computational parameters used for turf generation, then establish relationships between post-buckling stress, initial elastic modulus and buckling wavelength on statistical turf parameters. Finally, we analyze the reorientation of buckling planes of individual CNTs during the collective buckling process.

  20. Reduction and fragmentation of elastic fibers in the skin of obese mice is associated with altered mRNA expression levels of fibrillin-1 and neprilysin.

    PubMed

    Makihara, Hiroko; Hidaka, Moeko; Sakai, Yui; Horie, Yoshiko; Mitsui, Hideaki; Ohashi, Kenichi; Goshima, Yoshio; Akase, Tomoko

    2017-09-01

    Our previous research suggested that obesity induces structural fragility in the skin. Elastic fibers impart strength and elasticity. In this study, we determined whether elastic fibers decrease in the skin of obese mice. To confirm alterations in elastic fiber content due to obesity, we used spontaneously obese model mice (TSOD) and control mice (TSNO). Furthermore, to evaluate the elastin structure and gene expression dependent on the severity of obesity, an obesity-enhanced mouse model was developed by feeding a high fat diet to TSOD (TSOD-HF). Back skin samples were stained with hematoxylin and eosin and Elastica van Gieson for microscopic examination, and the samples were stained for immunohistochemical analysis of neprilysin. Gene expression levels were determined using a real-time PCR system. The abundance of elastic fibers beneath the epidermis was remarkably reduced and fragmented in TSOD as compared with TSNO. Fibrillin-1 mRNA levels in TSOD were significantly suppressed compared with those in TSNO, whereas neprilysin mRNA levels and immunohistochemical expression in TSOD were significantly increased, as compared with those in TSNO. The reduction of elastic fibers was enhanced and the expression levels of elastic fiber formed factors were significantly suppressed in TSOD-HF, as compared with those in the TSOD. The abundance of elastic fibers was reduced and fragmented in obesity, suggesting that the reduction in elastic fibers is initially caused by increased neprilysin and decreased fibrillin-1 expression, which may inhibit formation and stabilization of elastic fibers, resulting in skin fragility in obesity.

  1. Distribution of elastic fibers in the head and neck: a histological study using late-stage human fetuses

    PubMed Central

    Kinoshita, Hideaki; Umezawa, Takashi; Omine, Yuya; Kasahara, Masaaki; Rodríguez-Vázquez, José Francisco; Murakami, Gen

    2013-01-01

    There is little or no information about the distribution of elastic fibers in the human fetal head. We examined this issue in 15 late-stage fetuses (crown-rump length, 220-320 mm) using aldehyde-fuchsin and elastica-Masson staining, and we used the arterial wall elastic laminae and external ear cartilages as positive staining controls. The posterior pharyngeal wall, as well as the ligaments connecting the laryngeal cartilages, contained abundant elastic fibers. In contrast with the sphenomandibular ligament and the temporomandibular joint disk, in which elastic fibers were partly present, the discomalleolar ligament and the fascial structures around the pterygoid muscles did not have any elastic fibers. In addition, the posterior marginal fascia of the prestyloid space did contain such fibers. Notably, in the middle ear, elastic fibers accumulated along the tendons of the tensor tympani and stapedius muscles and in the joint capsules of the ear ossicle articulations. Elastic fibers were not seen in any other muscle tendons or vertebral facet capsules in the head and neck. Despite being composed of smooth muscle, the orbitalis muscle did not contain any elastic fibers. The elastic fibers in the sphenomandibular ligament seemed to correspond to an intermediate step of development between Meckel's cartilage and the final ligament. Overall, there seemed to be a mini-version of elastic fiber distribution compared to that in adults and a different specific developmental pattern of connective tissues. The latter morphology might be a result of an adaptation to hypoxic conditions during development. PMID:23560235

  2. Visual force sensing with flexible nanowire buckling springs

    NASA Astrophysics Data System (ADS)

    Dobrokhotov, Vladimir V.; Yazdanpanah, Mehdi M.; Pabba, Santosh; Safir, Abdelilah; Cohn, Robert W.

    2008-01-01

    A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire, referred to as a 'nanoneedle', is interpreted to determine the applied force. An individual needle of 157 nm diameter by 15.6 µm length is grown on an atomic force microscope (AFM) cantilever with a desired orientation (by the method of Yazdanpanah et al 2005 J. Appl. Phys. 98 073510). Using a nanomanipulator the needle is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model (De Bona and Zelenika 1997 Proc. Inst. Mech. Eng. C 211 509-17). In this calibration the elastic modulus (68.3 GPa) was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. The practical value of the sensing method does depend on the reliability and ruggedness of the needle. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.

  3. Visual force sensing with flexible nanowire buckling springs.

    PubMed

    Dobrokhotov, Vladimir V; Yazdanpanah, Mehdi M; Pabba, Santosh; Safir, Abdelilah; Cohn, Robert W

    2008-01-23

    A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire, referred to as a 'nanoneedle', is interpreted to determine the applied force. An individual needle of 157 nm diameter by 15.6 µm length is grown on an atomic force microscope (AFM) cantilever with a desired orientation (by the method of Yazdanpanah et al 2005 J. Appl. Phys. 98 073510). Using a nanomanipulator the needle is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model (De Bona and Zelenika 1997 Proc. Inst. Mech. Eng. C 211 509-17). In this calibration the elastic modulus (68.3 GPa) was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. The practical value of the sensing method does depend on the reliability and ruggedness of the needle. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.

  4. Pressure controlled clamp using shape memory alloy for minimal vessel invasion in blood flow occlusion.

    PubMed

    Zhang, Ye; Kanetaka, Hiroyasu; Sano, Yuya; Kano, Mitsuhiro; Kudo, Tadaaki; Sato, Takumi; Shimizu, Yoshinaka

    2013-01-01

    Vessel damage after clamping may affect the success of surgical operations. A new pressure controlled clamp (SMA clamp) was designed using super elastic property of shape memory alloy (SMA) to realize atraumatic vessel occlusion. The ability and biological effect of the SMA clamp to control pressure was investigated in vivo. The loading-displacement curves of the SMA clamps (experimental group) and conventional clamp (control group) by occlusion of pig carotid arteries were evaluated using a clamping-pressure analyzing system. To investigate macroscopically and histologically the vessel damage of the SMA and conventional clamps, pig carotid arteries were stained with Evan's blue and its histological sections were stained with Elastica Massion after clamping for fifteen minutes. Constant value was shown in the loading-displacement curve of SMA clamp. In the control group, damaged area stained with Evan's blue in the vessel wall showed enlargement with the pressure increasing. Less areas in experimental groups are observed than that in the control group. Histological section in the experimental group showed no obvious except a slight compressive damage in the tunica intima. In the control group, vessel wall showed irreversible damages. This experiment indicated that the SMA clamp, which has a unique mechanical property, can be used without vessels damage. This pressure controlled clamp can be a selection in clinical apparatus to improve surgical safety.

  5. Experimental investigations of the large deflection capabilities of a compliant parallel mechanism actuated by shape memory alloy wires

    NASA Astrophysics Data System (ADS)

    Sreekumar, M.; Nagarajan, T.; Singaperumal, M.

    2008-12-01

    This experimental study investigates the coupled effect of the force developed by the shape memory alloy (SMA) actuators and the force required for the large deflection of an elastica member in a compliant parallel mechanism. The compliant mechanism developed in house consists of a moving platform mounted on a superelastic pillar and three SMA wire actuators to manipulate the platform. A three-axis MEMS accelerometer has been mounted on the moving platform to measure its tilt angle. Three miniature force sensors have been designed and fabricated out of cantilever beams, each mounted with a pair of strain gauges, to measure the force developed by the respective actuators. The force sensors are highly sensitive and cost effective compared to commercially available miniature force sensors. Calibration of the force sensors has been accomplished with known weights, and for the three-axis MEMS accelerometer a rotary base has been considered which is usually used in optical applications. The calibration curves obtained, with R-squared values between 0.9997 and 1.0, show that both the tilt and force sensors considered are most appropriate for the respective applications. The mechanism fixed with the sensors and the drivers for the SMA actuators is integrated with a National Instrument's data acquisition system. The experimental results have been compared with the analytical results and it was found that the relative error is less than 2%. This is a preliminary study in the development of a mechanism for eye prosthesis and similar applications.

  6. Rubber particles from four different species, examined by transmission electron microscopy and electron-paramagnetic-resonance spin labeling, are found to consist of a homogeneous rubber core enclosed by a contiguous, monolayer biomembrane

    PubMed

    Cornish; Wood; Windle

    1999-11-01

    The physical characteristics of rubber particles from the four rubber (cis-1,4-polyisoprene) producing species Euphorbia lactiflua Phil., Ficus elastica Roxb., Hevea brasiliensis Mull. Arg., and Parthenium argentatum Gray, were investigated using transmission electron microscopy (TEM) and electron-paramagnetic-resonance (EPR) spin labeling spectroscopy. Transmission electron microscopy showed the rubber particles to be composed of a spherical, homogeneous, core of rubber enclosed by a contiguous, electron-dense, single-track surface layer. The biochemical composition of the surface layer and its single-track TEM suggested that a monolayer biomembrane was the surface structure most compatible with the hydrophobic rubber core. The EPR spectra for a series of positional isomers of doxyl stearic acid, used to label the surface layer of the rubber particles, exhibited flexibility gradients and evidence for lipid-protein interactions for all four rubber particle types that is consistent with a biomembrane-like surface. The EPR spectra confirmed that the surface biomembrane is a monolayer. Thus, rubber particles appear similar to oil bodies in their basic architecture. The EPR spectra also provided information on protein location and degree of biomembrane penetration that correlated with the known properties of the rubber-particle-bound proteins. The monolayer biomembrane serves as an interface between the hydrophobic rubber interior and the aqueous cytosol and prevents aggregation of the particles. An unexpected observation for the probes in pure polyisoprene was evidence of an intrinsic flexibility gradient associated with the stearic acid molecule itself.

  7. Initiation of rubber biosynthesis: In vitro comparisons of benzophenone-modified diphosphate analogues in three rubber-producing species.

    PubMed

    Xie, Wenshuang; McMahan, Colleen M; Degraw, Amanda J; Distefano, Mark D; Cornish, Katrina; Whalen, Maureen C; Shintani, David K

    2008-10-01

    Natural rubber, cis-1,4-polyisoprene, is a vital industrial material synthesized by plants via a side branch of the isoprenoid pathway by the enzyme rubber transferase. While the specific structure of this enzyme is not yet defined, based on activity it is probably a cis-prenyl transferase. Photoactive functionalized substrate analogues have been successfully used to identify isoprenoid-utilizing enzymes such as cis- and trans-prenyltransferases, and initiator binding of an allylic pyrophosphate molecule in rubber transferase has similar features to these systems. In this paper, a series of benzophenone-modified initiator analogues were shown to successfully initiate rubber biosynthesis in vitro in enzymatically-active washed rubber particles from Ficus elastica, Heveabrasiliensis and Parthenium argentatum. Rubber transferases from all three species initiated rubber biosynthesis most efficiently with farnesyl pyrophosphate. However, rubber transferase had a higher affinity for benzophenone geranyl pyrophosphate (Bz-GPP) and dimethylallyl pyrophosphate (Bz-DMAPP) analogues with ether-linkages than the corresponding GPP or DMAPP. In contrast, ester-linked Bz-DMAPP analogues were less efficient initiators than DMAPP. Thus, rubber biosynthesis depends on both the size and the structure of Bz-initiator molecules. Kinetic studies thereby inform selection of specific probes for covalent photolabeling of the initiator binding site of rubber transferase.

  8. Serum reactivity to other indoor ficus plants in patients with allergy to weeping fig (Ficus benjamina).

    PubMed

    Axelsson, I G; Johansson, S G; Larsson, P H; Zetterström, O

    1991-02-01

    Ornamental plants have long been used for indoor decoration. An example is the india rubber tree (Ficus elastica). With the increased popularity of green plants, both in private homes and public premises, small-leaf species, such as weeping fig or Ficus benjamina (Fb), have become widely used. Exposure to dust from Fb may cause sensitization and allergic airway symptoms, which among occupationally exposed plant keepers occur both in atopics and non-atopics. The serum reactivity to sap extracts from Fb and seven other indoor plants of the genus Ficus were investigated with RAST and a RAST inhibition technique, using sera from 12 atopic subjects and 12 plant keepers, sensitized to Fb. The allergenic similarity between the different extracts was found to be extensive. The specific IgE antibodies with the highest concentrations in serum were those against Fb and its variegate form, "star light", with decreasing values for the other species, especially those with larger leaves. The binding of IgE antibodies to the other Ficus RAST discs could be completely inhibited by extract of Fb. These reactions were probably due to cross-reactivity. Sensitization is believed to occur by inhalation of allergen-enriched dust, emanating from the leaves of the plants. The high allergenic potency of the species with many small leaves may be due to their large total leaf area.

  9. Reconfiguration of a flexible fiber immersed in a 2D dense granular flow close to the jamming transition

    NASA Astrophysics Data System (ADS)

    Kolb, Evelyne; Algarra, Nicolas; Vandembroucq, Damien; Lazarus, Arnaud

    2015-11-01

    We propose a new fluid/structure interaction in the unusual case of a dense granular medium flowing against an elastic fibre acting as a flexible intruder. We experimentally studied the deflection of a mylar flexible beam clamped at one side, the other free side facing a 2D granular flow in a horizontal cell moving at a constant velocity. We investigated the reconfiguration of the fibre as a function of the fibre's rigidity and of the granular packing fraction close but below the jamming in 2D. Imposing the fibre geometry like its length or thickness sets the critical buckling force the fibre is able to resist if it was not supported by lateral grains, while increasing the granular packing fraction might laterally consolidate the fibre and prevent it from buckling. But on the other side, the approach to jamming transition by increasing the granular packing fraction will be characterized by a dramatically increasing size of the cluster of connected grains forming a solid block acting against the fibre, which might promote the fibre's deflection. Thus, we investigated the granular flow fields, the fibre's deflexion as well as the forces experienced by the fibre and compared them with theoretical predictions from elastica for different loadings along the fibre. PMMH, CNRS UMR 7636, UPMC, ESPCI-ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.

  10. Segmental mediolytic arteritis involving hepatic arteries.

    PubMed

    Armas, O A; Donovan, D C

    1992-05-01

    Segmental mediolytic arteritis is a rare, noninflammatory arteriopathy that involves the splanchnic arteries of adults with shock and the coronary arteries of neonates with hypoxemia. We report the first case (to our knowledge) of segmental mediolytic arteritis involving the hepatic arteries. The lesion begins with cytoplasmic vacuolar degeneration of the arterial smooth-muscle cells, which then progresses to coalescence of vacuoles, leading to disruption of the media, intramural hemorrhage, and periadventitial fibrin deposition. Segmental mediolysis results in arterial wall defects, which can lead to dissecting aneurysms or hemorrhage due to arterial rupture. The intima and internal elastica are spared from the lytic process, and there is minimal periadventitial inflammation. Segmental mediolytic arteritis is not a true arteritis; therefore, segmental mediolytic arteriopathy may be a preferable term. Morphological similarities exist between segmental mediolytic arteritis and arterial fibromuscular dysplasia. In our case, hepatic ischemia correlated with mediolysis involving the hepatic arterial branches. Segmental mediolytic arteritis is thought to be due to an inappropriate vasospastic response, developing in the setting of hypoperfusion and hypoxemia.

  11. Melorheostosis and somatic mosaicism

    SciTech Connect

    Fryns, J.P.

    1995-08-28

    Melorheostosis is a rare congenital disorder of the bone and mesenchymal tissue. The longitudinal, cortical hyperostosis in the long bones has the appearance of wax flowing down the side of a candle. The short bones appear to manifest endosteal bone deposition. Usually only one limb is affected, but bilateral involvement is possible. Also, the skull, vertebrae, pelvis, and ribs can be affected. In 1980 we reported on a 3-year-old girl with clinical and radiological findings of melorheostosis, with manifest involvement of the left lower limb and scleroderma of the overlying soft tissues. Subsequently, at age 17 years, she was admitted to the Orthopedic Department for an Ilizarov operation comprising lengthening and axis correction of the left tibia. Arterial hypertension (220/130 mm Hg) was noted, and biochemical studies documented high plasma renin activity and high aldosterone concentrations. Renal studies showed a small left kidney, and angiography showed several intrarenal high-grade stenoses of the left renal artery with poor opacification, and spotted nephrogram of the middle part and upper pole. Partial nephrectomy with removal of the upper and middle poles of the left kidney was performed. Pathological examination of the small and large blood vessels showed marked intimal proliferation and splitting of the elastica. 3 refs.

  12. Approximate Solutions for a Self-Folding Problem of Carbon Nanotubes

    SciTech Connect

    Y Mikata

    2006-08-22

    This paper treats approximate solutions for a self-folding problem of carbon nanotubes. It has been observed in the molecular dynamics calculations [1] that a carbon nanotube with a large aspect ratio can self-fold due to van der Waals force between the parts of the same carbon nanotube. The main issue in the self-folding problem is to determine the minimum threshold length of the carbon nanotube at which it becomes possible for the carbon nanotube to self-fold due to the van der Waals force. An approximate mathematical model based on the force method is constructed for the self-folding problem of carbon nanotubes, and it is solved exactly as an elastica problem using elliptic functions. Additionally, three other mathematical models are constructed based on the energy method. As a particular example, the lower and upper estimates for the critical threshold (minimum) length are determined based on both methods for the (5,5) armchair carbon nanotube.

  13. In-vivo holmium laser angioplasty

    NASA Astrophysics Data System (ADS)

    Haase, Karl K.; Hassenstein, Stefan; Hanke, Hartmut; Hanke, Sybille; Oberhoff, Martin; Karsch, Karl R.

    1992-08-01

    Holmium laser angioplasty was performed in the atheromatous carotid artery of 10 rabbits to evaluate this mid-infrared laser as an alternative energy source for angioplasty. An additional 10 rabbits served as a control group. The laser emitted light at a wavelength of 2120 nm with pulse durations of 150 microsecond(s) . The energy density was 17.5 J/cm2. Cross sections were analyzed in regard to laser specific injury 7 and 14 days following laser irradiation. Staining of (alpha) -actin was used to identify smooth muscle cells (SMC), and bromodesoxyuridine labeling was carried out to determine the extent of proliferating cells. Integrity of the lamina elastica interna fibers was disrupted in 6 of 10 animals. In all animals, loss of medial SMCs was observed 7 and 14 days after treatment. Quantification of SMCs undergoing DNA synthesis in the intima and media showed a significant increase of labelled cells following laser irradiation. This proliferative response resulted in a significant increase of intimal thickening after laser ablation.

  14. Damage from periorbital ageing to the multilayered structures and resilience of the skin in Chinese population.

    PubMed

    Liao, Chuh-Kai; Tsai, Feng-Chou; Fong, Tsorng-Harn; Hu, Chien-Ming; Wei, Po-Li; Su, Ching-Hua

    2013-06-01

    Ageing dynamically disrupts the multilayered supporting components of the skin that are held together by cell adhesion molecules (CAMs). Skin specimens from 33 female Chinese patients undergoing lower blepharoplasty were divided into three age groups and examined by haematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) and Elastica-van Gieson (EVG) stains, western blotting, surface electron microscopy (SEM) and biomechanical tension analysis. The SEM density (skin surface topology) showed a negative linear relationship with age. The triangular pattern of the skin surface in the younger group gradually broke down into quadrangular and irregular patterns in the older group. Collagens and elastic fibres in the dermis showed anisotropy and decreased density in the older groups compared with the younger group, especially in the papillary dermis. Anisotropy means that physical properties differ according to the direction of measurement. E-cadherin and integrin αv (whose functions are to bind epidermal and dermal elements respectively) increased and decreased, respectively, in the oldest group. Skin resilience decreased significantly in this group under repetitive stress. In conclusion, a loss of skin surface textures, integrin αv expressions, epidermal-dermal connections and dermal compactness led to the multilayered structure of the skin becoming separated. This in turn decreased resilience during ageing. These findings may therefore explain why aged skins cannot tolerate repetitive facial expressions, and why this action produces further dynamic wrinkles. © 2013 The Authors. International Journal of Experimental Pathology © 2013 International Journal of Experimental Pathology.

  15. Curling dynamics of naturally curved ribbons from high to low Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Albarran Arriagada, Octavio; Massiera, Gladys; Abkarian, Manouk

    2012-11-01

    Curling deformation of thin elastic sheets appears in numerous structures in nature, such as membranes of red blood cells, epithelial tissues or green algae colonies to cite just a few examples. However, despite its ubiquity, the dynamics of curling propagation in a naturally curved material remains still poorly investigated. Here, we present a coupled experimental and theoretical study of the dynamical curling deformation of naturally curved ribbons. Using thermoplastic and metallic ribbons molded on cylinders of different radii, we tune separately the natural curvature and the geometry to study curling dynamics in air, water and in viscous oils, thus spanning a wide range of Reynolds numbers. Our theoretical and experimental approaches separate the role of elasticity, gravity and hydrodynamic dissipation from inertia and emphasize the fundamental differences between the curling of a naturally curved ribbon and a rod described by the classical Elastica. Our work shows evidence for the propagation of a single instability front, selected by a local buckling condition. We show that depending on gravity, and both the Reynolds and the Cauchy numbers, the curling speed and shape are modified by the large scale drag and the local lubrication forces. This work was supported by the French Ministry of Research, the CNRS Physics-Chemistry-Biology Interdisciplinary Pro- gram, the University Montpellier 2 Interdisciplinary Program and the Region Languedoc-Roussillon.

  16. Exon-primed intron-crossing (EPIC) markers for evolutionary studies of Ficus and other taxa in the fig family (Moraceae)1

    PubMed Central

    Yao, Xiaohong; Li, Chenhong; Dick, Christopher W.

    2013-01-01

    • Premise of the study: The genus Ficus (fig trees) comprises ca. 750 species of trees, vines, and stranglers found in tropical forests throughout the world. Fig trees are keystone species in many tropical forests, and their relationship with host-specific wasp pollinators has received much attention, although many questions remain unresolved regarding the levels of host specificity, cospeciation, and the role of hybridization in fig and wasp speciation. We developed exon-primed intron-crossing (EPIC) markers to obtain phylogenetic resolution needed to address these questions. • Methods and Results: Expressed sequence tags (ESTs) from F. elastica were compared to Arabidopsis and Populus genomes to locate introns and to design primers in flanking exons. Primer pairs for 80 EPIC markers were tested in samples from divergent clades within Ficus and the outgroup Poulsenia (Moraceae). • Conclusions: Thirty-one EPIC markers were successfully sequenced across Ficus, and 29 of the markers also amplified in Poulsenia, indicating broad transferability within Moraceae. All of the EPIC markers were polymorphic and showed levels of polymorphism similar to that of the widely used internal transcribed spacer (ITS). PMID:25202490

  17. Phylogeny, biogeography, and ecology of Ficus section Malvanthera (Moraceae).

    PubMed

    Rønsted, Nina; Weiblen, George D; Savolainen, V; Cook, James M

    2008-07-01

    We conducted the first molecular phylogenetic study of Ficus section Malvanthera (Moraceae; subgenus Urostigma) based on 32 Malvanthera accessions and seven outgroups representing other sections of Ficus subgenus Urostigma. We used DNA sequences from the nuclear ribosomal internal and external transcribed spacers (ITS and ETS), and the glyceraldehyde-3-phosphate dehydrogenase (G3pdh) region. Phylogenetic analysis using maximum parsimony, maximum likelihood and Bayesian methods recovered a monophyletic section Malvanthera to the exclusion of the rubber fig, Ficus elastica. The results of the phylogenetic analyses do not conform to any previously proposed taxonomic subdivision of the section and characters used for previous classification are homoplasious. Geographic distribution, however, is highly conserved and Melanesian Malvanthera are monophyletic. A new subdivision of section Malvanthera reflecting phylogenetic relationships is presented. Section Malvanthera likely diversified during a period of isolation in Australia and subsequently colonized New Guinea. Two Australian series are consistent with a pattern of dispersal out of rainforest habitat into drier habitats accompanied by a reduction in plant height during the transition from hemi-epiphytic trees to lithophytic trees and shrubs. In contradiction with a previous study of Pleistodontes phylogeny suggesting multiple changes in pollination behaviour, reconstruction of changes in pollination behaviour on Malvanthera, suggests only one or a few gains of active pollination within the section.

  18. Evaluation of unique elastic aggregates (elastic globes) in normal facial skin by multiphoton laser scanning tomography.

    PubMed

    Sugata, Keiichi; Osanai, Osamu; Sano, Tomohiko; Akiyama, Minoru; Fujimoto, Norihiro; Tajima, Shingo; Takema, Yoshinori

    2015-04-01

    There is no reliable marker to estimate the degree of skin aging in vivo. It now has become possible to quantitatively determine the dermal characteristics of the extracellular matrix (ECM) in vivo using multiphoton laser tomography (MLT). Fifty-seven healthy Japanese female volunteers, aged from 20 to 60 years old, were examined using multiphoton depth-resolved measurements of autofluorescence (AF) and second harmonic generation (SHG) at three sites on their right cheek. Paraffin-embedded skin specimens obtained from the faces of 12 normal individuals aged 38-68 years old were stained with Elastica van Gieson (EVG). We found unique elastic aggregates at a 20 μm depth from the dermo-epidermal junction (DEJ) in vivo which increased in size with aging of subjects from 20 to 60 years old. SHG fibers seemed to surround those elastic aggregates. Histological examination of specimens from normal individuals stained with EVG confirmed the occurrence of elastic aggregates with varied sizes just beneath the epidermis or hair follicles. The elastic aggregates are morphologically similar to previously described 'elastic globes' and can serve as a marker of the early stage of photoaging. MLT will contribute to determine age-related dermal changes using a non-invasive technique.

  19. Biosynthetic Nanostructured Cellulose Patch for Chest Wall Reconstruction: Five-Month Follow-up in a Porcine Model.

    PubMed

    Zhang, Ruoyu; Mägel, Lavinia; Jonigk, Danny; Länger, Florian; Lippmann, Torsten; Zardo, Patrick; Pölzing, Frank

    2017-10-01

    Ideal approaches and materials for reconstruction of large chest wall defects remain a topic of debate. We sought to explore the suitability of a reinforced nanostructured cellulose (NC) patch for chest wall reconstruction in an animal model. In four domestic pigs, a standardized 10 × 10 cm chest wall defect was created by resecting three rib segments. Subsequently the defect was reconstructed via a biosynthetic NC patch (16 × 12 cm) reinforced by polytetrafluoroethylene mesh. After 1, 2, 4, and 5 months respectively, gross examination of NC patches was performed following sacrifice of the animals. Specimens of NC patches and surrounding connective tissue underwent histological examinations after staining with Hematoxylin-eosin and Elastica van Gieson. All animals survived their observation period without encountering major adverse events. On gross examination all NC patches were intact and well integrated into the surrounding tissue. Histological examination showed clearly demarked zones of foreign body reaction at the patch/host-tissue interface. After 5 months a slight increase in foreign body reaction, fibrous capsule formation and cellular infiltration were observed. No signs of fibroblast proliferation or neovascularization were seen within NC patches at any point. Our findings suggest a quick healing process and good overall biocompatibility following NC patch implantation.NC might prove an efficient and suitable biomaterial for complex chest wall reconstruction.

  20. Strain tensor selection and the elastic theory of incompatible thin sheets

    NASA Astrophysics Data System (ADS)

    Oshri, Oz; Diamant, Haim

    2017-05-01

    The existing theory of incompatible elastic sheets uses the deviation of the surface metric from a reference metric to define the strain tensor [Efrati et al., J. Mech. Phys. Solids 57, 762 (2009), 10.1016/j.jmps.2008.12.004]. For a class of simple axisymmetric problems we examine an alternative formulation, defining the strain based on deviations of distances (rather than distances squared) from their rest values. While the two formulations converge in the limit of small slopes and in the limit of an incompressible sheet, for other cases they are found not to be equivalent. The alternative formulation offers several features which are absent in the existing theory. (a) In the case of planar deformations of flat incompatible sheets, it yields linear, exactly solvable, equations of equilibrium. (b) When reduced to uniaxial (one-dimensional) deformations, it coincides with the theory of extensible elastica; in particular, for a uniaxially bent sheet it yields an unstrained cylindrical configuration. (c) It gives a simple criterion determining whether an isometric immersion of an incompatible sheet is at mechanical equilibrium with respect to normal forces. For a reference metric of constant positive Gaussian curvature, a spherical cap is found to satisfy this criterion except in an arbitrarily narrow boundary layer.

  1. Chronological changes in the collagen-type composition at tendon-bone interface in rabbits.

    PubMed

    Tabuchi, K; Soejima, T; Kanazawa, T; Noguchi, K; Nagata, K

    2012-09-01

    The purpose of this study was to evaluate chronological changes in the collagen-type composition at tendon-bone interface during tendon-bone healing and to clarify the continuity between Sharpey-like fibres and inner fibres of the tendon. Male white rabbits were used to create an extra-articular bone-tendon graft model by grafting the extensor digitorum longus into a bone tunnel. Three rabbits were killed at two, four, eight, 12 and 26 weeks post-operatively. Elastica van Gieson staining was used to colour 5 µm coronal sections, which were examined under optical and polarised light microscopy. Immunostaining for type I, II and III collagen was also performed. Sharpey-like fibres comprised of type III collagen in the early phase were gradually replaced by type I collagen from 12 weeks onwards, until continuity between the Sharpey-like fibres and inner fibres of the tendon was achieved by 26 weeks. Even in rabbits, which heal faster than humans, an observation period of at least 12 to 26 weeks is required, because the collagen-type composition of the Sharpey-like fibre bone-tendon connection may have insufficient pullout strength during this period. These results suggest that caution is necessary when permitting post-operative activity in humans who have undergone intra-bone tunnel grafts.

  2. Self-burial mechanics of hygroscopically active awns

    NASA Astrophysics Data System (ADS)

    Jung, Wonjong; Kim, Wonjung; Kim, Ho-Young

    2013-11-01

    We present the results of a combined experimental and theoretical investigation of the mechanics of self-burial of some plant seeds whose morphologies respond to humidity change of the surroundings. The seeds of Pelargonium species have hygroscopically active awns that play a critical role in the dispersal from the parent plant and burial in soil. While the awn uncoils to a linear shape in a highly humid condition, it recoils to a helical shape when dry. The rotation is driven by the structure of the cell walls that are comprised of cellulose microfibers aligned in a tilted helix. During uncoiling of the awn, the revolving tail generates thrust to burrow into soil, so that the seed is self-buried. We present the direct observation of the self-burial of the seed with the thrust into a soft substrate being measured at the same time. The elastica theory allows us to rationalize this botanical digging mechanics using the structural deformations of the hygroexpansive tissues. This work was supported by the Sogang University Research Grant of 2013 (201310009.01) and the National Research Foundation of Korea (grant no. 2012-008023).

  3. Linear skin atrophy, scarring alopecia, anonychia, and tongue lesion: a "new" syndrome?

    PubMed

    Sequeiros, J; Sack, G H

    1985-08-01

    One of a pair of female monozygotic twins showed skin atrophy with linear alternation of depressed scarlike areas and intervening ridges of normal or nearly normal skin. She was born with friable skin and a vesicular-bullous eruption which was followed by gradual scabbing. Hypohidrosis in the affected areas, heat intolerance, and febrile convulsions were noted in infancy and childhood. No new skin lesions developed, and the existing ones, the sweating disturbance, and the heat intolerance gradually improved with time. Scarring alopecia, congenital absence of three toenails, and a scarlike lesion of the tongue were also present. Their absence in the other twin supports the view that 1) these manifestations all are part of the same syndrome, and 2) this syndrome is nongenetic. Histologically, there were no diagnostic or consistent findings, but the number of skin appendages was diminished, and the elastic fibers were reduced in number and size in one biopsy. The calculated probability for the twins being monozygotic was 0.9998. This family was also remarkable for the presence of alopecia areata in three successive generations with only one instance of apparent nonpenetrance. We conclude that this may represent a previously undescribed syndrome of congenital fragility of connective tissue which predisposed to damage of the elastica, possibly caused by an early inflammatory phase.

  4. Three-dimensional regular arrangement of the annular ligament of the rat stapediovestibular joint.

    PubMed

    Ohashi, Mitsuru; Ide, Soyuki; Kimitsuki, Takashi; Komune, Shizuo; Suganuma, Tatsuo

    2006-03-01

    The stapes footplate articulates with the vestibular window through the annular ligament. This articulation is known as the stapediovestibular joint (SVJ). We investigated the ultrastructure of adult rat SVJ and report here on the characteristic ultrastructure of the corresponding annular ligament. Transmission electron microscopy showed that this annular ligament comprises thick ligament fibers consisting of a peripheral mantle of microfibrils and an electron-lucent central amorphous substance that is regularly arranged in a linear fashion, forming laminated structures parallel to the horizontal plane of the SVJ. Scanning electron microscopy revealed that transverse microfibrils cross the thick ligament fibers, showing a lattice-like structure. The annular ligament was vividly stained with elastica van Gieson's stain and the Verhoeff's iron hematoxylin method. Staining of the electron-lucent central amorphous substance of the thick ligament fibers by the tannate-metal salt method revealed an intense electron density. These results indicate that the annular ligament of the SVJ is mainly composed of mature elastic fibers.

  5. Diuretic and natriuretic activity of two mistletoe species in rats

    PubMed Central

    Jadhav, Namita; Patil, C. R.; Chaudhari, K. B.; Wagh, J. P.; Surana, S. J.; Jadhav, R. B.

    2010-01-01

    In different cultural groups, the hemiparasitic plants of the families Loranthaceae and Viscaceae (mistletoes) are frequently used in the treatment of hypertension and/or as diuretic agents. However, it remains unclear as to what commonality makes them diuretic agents or a remedy for hypertension. In this article, the diuretic activity of methanol extracts of Viscum articulatum (VA) Burm. f. and Helicanthus elastica (HE) (Ders.) Dans. in rats is reported. The extracts were administered orally at doses of 100, 200 and 400 mg/kg to rats that had been fasted and deprived of water for 18 hours. Investigations were carried out for diuretic, saluretic and natriuretic effects. The polyphenolic and triterpenoid contents were determined quantitatively using chemical assays and high performance liquid chromatography (HPLC) analysis, respectively. The extracts of VA and HE demonstrated significant and dose-dependent diuretic activity in rats. It was found that while VA mimics the furosemide pattern, HE demonstrated a dose-dependent increase in diuresis, along with an increase in potassium-sparing effects. Phytochemical analysis revealed that polyphenolics and triterpenoids, such as oleanolic acid and lupeol, are the major phytochemicals involved. It was also found that in different combinations, these phytochemicals differed in the way they influenced the electrolyte excretion. A higher content of polyphenolics in association with lower triterpenoid content was found to favor potassium-sparing effects. PMID:21808540

  6. Optical multiple sample vacuum integrating sphere

    NASA Technical Reports Server (NTRS)

    Butner, C. L. (Inventor)

    1986-01-01

    An integrating sphere comprised of a uniform difusely reflecting spherical cavity, having mutually transverse input and output ports, and a linear sample transport mechanism is described. The sample transport mechanism is secured so that the multiple samples can be brought into registration with the input port, one at a time, without having to open or disassemble the apparatus when a change of sample is desired. A vacuum tight seal is provided between the cavity and the transport mechanism. This maintains the integrity of a vacuum generated with the sphere when attached to the source of optical energy. The device is utilized to test emissive characteristics such as the relative fluorescence quantum efficiency of a dye sample placed in the path of a monochromatic optical energy source coupled to the input port while having a light detector coupled to the output port.

  7. [Bilateral cerebellopontine arachnoid cyst].

    PubMed

    Gelabert-Gonzalez, M; Aran-Echabe, E; Pita-Buezas, L

    2016-06-16

    Introduccion. Los quistes aracnoideos bilaterales del angulo pontocerebeloso son excepcionales, y unicamente existen tres casos publicados en la bibliografia. Caso clinico. Niña de 14 años, previamente sana, que acude a consultas por presentar cefalea bifrontal de seis semanas de evolucion. La exploracion clinica era normal y la resonancia magnetica craneal mostraba dos lesiones extraaxiales localizadas en ambos angulos pontocerebelosos, siendo ligeramente mayor la izquierda. Las lesiones se comportaban como homogeneamente intensas en T1 e hiperintensas en T2, no captaban contraste y no existia restriccion en las secuencias de difusion. No se indico tratamiento quirurgico. Conclusiones. Los quistes aracnoideos bilaterales situados en el angulo pontocerebeloso son excepcionales. La principal indicacion para el tratamiento quirurgico es la presencia de sintomas o signos neurologicos coincidentes con la localizacion de los quistes.

  8. Source and loss processes of protons of the inner radiation belt.

    NASA Technical Reports Server (NTRS)

    Farley, T. A.; Walt, M.

    1971-01-01

    The adequacy of the known source and loss processes to populate the inner radiation belt with protons is examined by calculating the equilibrium trapped-proton distribution, which would result from decay of albedo neutrons, energy-loss collisions, and radial diffusion by changes in the third adiabatic invariant. The strength of the neutron source and the rates of atmospheric energy loss are obtained from available theoretical and experimental data, and the radial-diffusion coefficient is adjusted to give agreement between theory and experiment for equatorially trapped protons with first invariants between 200 and 3000 MeV gauss. The flux intensities, energy spectrums, and radial distributions obtained by the theory are in good agreement with observations, and the radial diffusion coefficient required is consistent with dif*usion coefficients derived by a variety of other methods.-

  9. First study on oyster-shell-based phosphorous removal in saltwater - A proxy to effluent bioremediation of marine aquaculture.

    PubMed

    Martins, Marta C; Santos, Eduarda B H; Marques, Catarina R

    2017-01-01

    The efficiency of oyster-shell waste for the removal of phosphorous (P) in saltwater was herein evaluated. For that, different factors were tested, being attained >56% and >98% P removal by natural oyster shell (NOS)-fraction <0.125mm and COS (calcined oyster shell)-fraction 0.5mm, respectively. Adsorption was the main mechanism suggested for NOS, whilst a co-mechanism of precipitation occurred with COS. NOS adsorption was consistent with Langmuir model and followed both the Elovich and Intraparticle Difusion kinetic models. COS followed only Pseudo-Second Order and, mainly, the Elovich model. Overall, optimal conditions for P removal from saltwater were established for NOS and COS, which will unquestionably allow to comply with regulated P levels for the discharge of wastewater from saltwater RAS. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Micelles of a diblock copolymer of styrene and ethylene oxide in mixtures of 2,6-lutidine and water.

    PubMed

    Tuzar, Z; Kadlec, P; Stepánek, P; Kríz, J; Nallet, F; Noirez, L

    2008-12-16

    We studied the micelle formation of a diblock copolymer of styrene and ethylene oxide in mixtures of 2,6-dimethylpyridine (2,6-lutidine) and water. Micelles are formed in a broad solvent composition range with a volume fraction of water ranging from 0.05 to 0.85, where neither polystyrene nor polyethylene oxide homopolymers are soluble. The diffusion behavior of pure solvent mixtures and in solutions of copolymer micelles is reported. In LTD/water mixtures, two diffusive processes corresponding to self-difusion and two modes belonging to mutual diffusion and diffusion of solvent clusters have been found. In copolymer solutions, the mode of copolymer micelle diffusion replaces the mode of solvent cluster diffusion. Quasielastic light scattering, small-angle neutron scattering, and pulsed-field gradient NMR have been employed in our study.

  11. [The role of diffusion tensor imaging in the pre-surgical study of temporal lobe epilepsy].

    PubMed

    Garcia-Pallero, M A; Torres, C V; Manzanares-Soler, R; Camara, E; Sola, R G

    2016-12-16

    Introduccion. La imagen por tensor de difusion (DTI) es una tecnica no invasiva que puede ser utilizada para evaluar la integridad de la sustancia blanca cerebral. Objetivo. Investigar la utilidad de la DTI en pacientes con epilepsia del lobulo temporal (ELT) y ver su relacion con la lateralizacion del foco epileptogeno en estos pacientes. Pacientes y metodos. Se analizan 11 pacientes diagnosticados de ELT segun el protocolo de evaluacion prequirurgica de nuestra unidad de epilepsia, y libres de crisis a los dos años de la realizacion de una lobectomia temporal mas amigdalohipocampectomia (tecnica de Spencer). Como parte de su estudio preoperatorio, se realiza una resonancia magnetica cerebral de 1,5 T con secuencia de tensor de difusion y se estudian, mediante un analisis basado en voxel, las diferencias en la conectividad entre el hemisferio intervenido y el contralateral. Resultados. Comparado con el hemisferio contralateral, se observo una reduccion de la anisotropia fraccional estadisticamente significativa (p < 0,05) en el cuerpo calloso, el cingulo, el fasciculo longitudinal superior, las radiaciones talamicas anteriores, la capsula interna, los nucleos ventral lateral y pulvinar del talamo, el fasciculo frontooccipital inferior, el fasciculo uncinado, el fasciculo longitudinal inferior y el giro parahipocampal ipsilaterales al foco epileptogeno. Conclusiones. La caracterizacion de las anormalidades en la conectividad de la sustancia blanca cerebral, a traves de la DTI en pacientes con ELT, puede tener un valor importante para la lateralizacion del foco epileptogeno en la evaluacion prequirurgica. Serian necesarios estudios con un numero mas elevado de pacientes para confirmar estos resultados.

  12. [Reversible alterations in the neuroimages associated with vigabatrine treatment in infants with epileptic spasms].

    PubMed

    Fernandez-Garcia, M A; Garcia-Penas, J J; Gomez-Martin, H; Perez-Sebastian, I; Garcia-Esparza, E; Sirvent-Cerda, S

    2017-02-16

    Introduccion. La vigabatrina (VGB) es un farmaco de primera linea para el tratamiento de espasmos infantiles. Diversos estudios han hallado anomalias en la resonancia magnetica (RM) cerebral, que afectaban particularmente a los ganglios de la base, y especialmente en secuencias de difusion, en lactantes con espasmos que recibian VGB en altas dosis (> 100 mg/kg/dia), y se ha observado la desaparicion de las lesiones tras la retirada de dicho tratamiento. Casos clinicos. Se presentan dos casos clinicos con inicio de una encefalopatia epileptica en el primer año de vida y crisis en forma de espasmos infantiles. Ambos recibieron tratamiento con distintos farmacos, entre ellos VGB hasta dosis de 200 mg/kg/dia. Con 11 y 28 meses de vida, respectivamente, aparecian imagenes en la RM cerebral con una marcada hiperintensidad de señal en secuencias ponderadas en T2 en ambos palidos, talamos, porcion posterior del tronco encefalico y nucleos dentados, que asociaban restriccion en secuencias de difusion. Ambos disponian de estudios previos de RM, sin alteraciones. Tras excluir una metabolopatia subyacente, se decidio la retirada de la VGB y tres meses despues, en una RM de control, se aprecio la total reversibilidad de dichas lesiones. Conclusiones. Deben evaluarse con cautela los hallazgos de la RM cerebral en lactantes que reciban VGB en altas dosis para el tratamiento de espasmos. Su aparente efecto citotoxico sobre los ganglios de la base podria simular metabolopatias/enfermedades mitocondriales. Conocer este efecto de la VGB y sus caracteristicas tipicas en la RM puede evitar pruebas innecesarias, como una biopsia muscular o un nuevo cribado metabolico.

  13. Dissolved organic carbon biodegradability from leaf litter leachates of riparian tropical trees

    NASA Astrophysics Data System (ADS)

    Bastianoni, A.; Montoya, J. V.; Mendez, C.; Paolini, J.

    2012-04-01

    It is generally assumed that leaf litter with varying chemical composition may show different rates of mass loss, dissolved organic carbon (DOC) release, and DOC biodegradability. Leaf litter is composed of different organic compounds, which may differ in their release rates. Some authors consider leaf litter chemical quality (carbon to nitrogen ratio (C:N) and polyphenolics content) as an indicator of leaf litter mass losses and DOC released into stream water through leaching. In this research, we determined if leachate's DOC biodegradability exhibited a positive relationship with leaf litter chemical quality and leaf litter mass loss due to leaching. In order to test these hypotheses, leaf litter from six riparian tree species (Bambusa vulgaris; Castilla elastica; Artocarpus altilis; Cecropia peltata; Hura crepitans and Ficus maxima), present in the lower reaches of a fifth-order stream in northern Venezuela was collected during the dry season of 2010. To evaluate leaf litter mass loss, air-dried leaves were incubated in Milli-Q water at room temperature in the dark. After 1h, 6h, 1d, 2d, 4d, 8d and 15d, microcosms were removed from the assay to determine remaining mass. DOC biodegradability was measured using 24 h leachates that were added into a 1L glass flask containing 250mL of unfiltered stream water, 4g of stream sediment, and nutrient amendments until all incubations had equal initial DOC concentrations. Biodegradability of DOC was measured at 0, 1, 2, 5 and 7 days as the decrease in DOC concentration through time. Chemical characterization of leaf litter involved the determination of total concentrations of C, N, and poliphenolics. Three replicates were used for all analyses. Initial chemical characterization of leaf litter showed that only two species (C. elastica and A. altilis), had similar C:N ratios (~31). The other four species, showed different C and N contents but presented C:N ratios between 21 and 23. Total polyphenolics content varied greatly

  14. Biomechanical and morphological properties of the multiparous ovine vagina and effect of subsequent pregnancy.

    PubMed

    Rynkevic, Rita; Martins, Pedro; Hympanova, Lucie; Almeida, Henrique; Fernandes, Antonio A; Deprest, Jan

    2017-05-24

    Pelvic floor soft tissues undergo changes during the pregnancy. However, the degree and nature of this process is not completely characterized. This study investigates the effect of subsequent pregnancy on biomechanical and structural properties of ovine vagina. Vaginal wall from virgin, pregnant (in their third pregnancy) and parous (one year after third vaginal delivery) Swifter sheep (n=5 each) was harvested. Samples for biomechanics and histology, were cut in longitudinal axis (proximal and distal regions). Outcome measurements describing Young's modulus, ultimate stress and elongation were obtained from stress-strain curves. For histology samples were stained with Miller's Elastica staining. Collagen, elastin and muscle cells and myofibroblasts contents were estimated, using image processing techniques. Statistical analyses were performed in order to determine significant differences among experimental groups. Significant regional differences were identified. The proximal vagina was stiffer than distal, irrespective the reproductive status. During the pregnancy proximal vagina become more compliant than in parous (+47.45%) or virgin sheep (+64.35%). This coincided with lower collagen (-15 to -21%), higher elastin (+30 to +60%), and more smooth muscle cells (+17 to +37%). Vaginal tissue from parous ewes was weaker than of virgins, coinciding with lower collagen (-10%), higher elastin (+50%), more smooth muscle cells (+20%). It could be proposed that after pregnancy biomechanical properties of vagina do not recover to those of virgins. Since elastin has a significant influence on the compliance of soft tissues and collagen is the main "actor" regarding strength, histological analysis performed in this study justifies the mechanical behavior observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Human Subperitoneal Fibroblast and Cancer Cell Interaction Creates Microenvironment That Enhances Tumor Progression and Metastasis

    PubMed Central

    Yokota, Mitsuru; Ishii, Genichiro; Saito, Norio; Aoyagi, Kazuhiko; Sasaki, Hiroki; Ochiai, Atsushi

    2014-01-01

    Backgrounds Peritoneal invasion in colon cancer is an important prognostic factor. Peritoneal invasion can be objectively identified as periotoneal elastic laminal invasion (ELI) by using elastica stain, and the cancer microenvironment formed by the peritoneal invasion (CMPI) can also be observed. Cases with ELI more frequently show distant metastasis and recurrence. Therefore, CMPI may represent a particular milieu that facilitates tumor progression. Pathological and biological investigations into CMPI may shed light on this possibly distinctive cancer microenvironment. Methods We analyzed area-specific tissue microarrays to determine the pathological features of CMPI, and propagated subperitoneal fibroblasts (SPFs) and submucosal fibroblasts (SMFs) from human colonic tissue. Biological characteristics and results of gene expression profile analyses were compared to better understand the peritoneal invasion of colon cancer and how this may form a special microenvironment through the interaction with SPFs. Mouse xenograft tumors, derived by co-injection of cancer cells with either SPFs or SMFs, were established to evaluate their active role on tumor progression and metastasis. Results We found that fibrosis with alpha smooth muscle actin (α-SMA) expression was a significant pathological feature of CMPI. The differences in proliferation and gene expression profile analyses suggested SPFs and SMFs were distinct populations, and that SPFs were characterized by a higher expressions of extracellular matrix (ECM)-associated genes. Furthermore, compared with SMFs, SPFs showed more variable alteration in gene expressions after cancer-cell-conditioned medium stimulation. Gene ontology analysis revealed that SPFs-specific upregulated genes were enriched by actin-binding or contractile-associated genes including α-SMA encoding ACTA2. Mouse xenograft tumors derived by co-injection of cancer cells with SPFs showed enhancement of tumor growth, metastasis, and capacity for

  16. Linking fruit traits to variation in predispersal vertebrate seed predation, insect seed predation, and pathogen attack.

    PubMed

    Beckman, Noelle G; Muller-Landau, Helene C

    2011-11-01

    The importance of vertebrates, invertebrates, and pathogens for plant communities has long been recognized, but their absolute and relative importance in early recruitment of multiple coexisting tropical plant species has not been quantified. Further, little is known about the relationship of fruit traits to seed mortality due to natural enemies in tropical plants. To investigate the influences of vertebrates, invertebrates, and pathogens on reproduction of seven canopy plant species varying in fruit traits, we quantified reductions in fruit development and seed germination due to vertebrates, invertebrates, and fungal pathogens through experimental removal of these enemies using canopy exclosures, insecticide, and fungicide, respectively. We also measured morphological fruit traits hypothesized to mediate interactions of plants with natural enemies of seeds. Vertebrates, invertebrates, and fungi differentially affected predispersal seed mortality depending on the plant species. Fruit morphology explained some variation among species; species with larger fruit and less physical protection surrounding seeds exhibited greater negative effects of fungi on fruit development and germination and experienced reduced seed survival integrated over fruit development and germination in response to vertebrates. Within species, variation in seed size also contributed to variation in natural enemy effects on seed viability. Further, seedling growth was higher for seeds that developed in vertebrate exclosures for Anacardium excelsum and under the fungicide treatment for Castilla elastica, suggesting that predispersal effects of natural enemies may carry through to the seedling stage. This is the first experimental test of the relative effects of vertebrates, invertebrates, and pathogens on seed survival in the canopy. This study motivates further investigation to determine the generality of our results for plant communities. If there is strong variation in natural enemy attack

  17. Effects of bFGF incorporated into a gelatin sheet on wound healing.

    PubMed

    Miyoshi, Michiyo; Kawazoe, Takeshi; Igawa, Hiroharu H; Tabata, Yasuhiko; Ikada, Yoshito; Suzuki, Shigehiko

    2005-01-01

    Basic fibroblast growth factor (bFGF) is well known to promote the proliferation of almost all cells associated with wound healing. However, as the activation duration of bFGF is very short in vivo, we incorporated bFGF into an acidic gelatin hydrogel and studied the sustained release of bFGF in vivo. In addition, we investigated the effects of the acidic gelatin sheet containing bFGF on wound healing. To distinguish wound contraction from neoepithelialization, we measured both the wound area and neoepithelium length. Other histological parameters such as thickness of granulation tissue and number of capillaries were also determined as indices of wound healing. Fibrous tissue was assessed using an Elastica van Gieson and Azan stain. A skin defect (1.5 x 1.5 cm) of full thickness was created on the back of each test mouse and the wound was covered with an acidic gelatin hydrogel, referred to as a gelatin sheet in this study (2 x 2 cm), with bFGF (100 microg/site) (A) or without bFGF (B). 1, 2, 3, 5, 7 and 14 days after covering, mice were killed and an enzyme-linked immunosorbent assay (ELISA) was performed to estimate the concentration of bFGF in the plasma. In another experiment, each wound was covered with (A), (B) or a hydrogel dressing (control group, C) and the wound area was measured 1 or 2 weeks postoperatively with a computer planimeter. The histological parameters, as mentioned above, were assessed using a light microscope. Sustained release of bFGF from the gelatin sheet was observed and the gelatin sheet containing bFGF promoted neoepithelialization, granulation, neovascularization and wound closure. This gelatin sheet containing bFGF was concluded to be effective for wound healing and promising for clinical use.

  18. General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation

    SciTech Connect

    Van Gorder, Robert A.

    2014-06-15

    In his study of superfluid turbulence in the low-temperature limit, Svistunov [“Superfluid turbulence in the low-temperature limit,” Phys. Rev. B 52, 3647 (1995)] derived a Hamiltonian equation for the self-induced motion of a vortex filament. Under the local induction approximation (LIA), the Svistunov formulation is equivalent to a nonlinear dispersive partial differential equation. In this paper, we consider a family of rotating vortex filament solutions for the LIA reduction of the Svistunov formulation, which we refer to as the 2D LIA (since it permits a potential formulation in terms of two of the three Cartesian coordinates). This class of solutions holds the well-known Hasimoto-type planar vortex filament [H. Hasimoto, “Motion of a vortex filament and its relation to elastica,” J. Phys. Soc. Jpn. 31, 293 (1971)] as one reduction and helical solutions as another. More generally, we obtain solutions which are periodic in the space variable. A systematic analytical study of the behavior of such solutions is carried out. In the case where vortex filaments have small deviations from the axis of rotation, closed analytical forms of the filament solutions are given. A variety of numerical simulations are provided to demonstrate the wide range of rotating filament behaviors possible. Doing so, we are able to determine a number of vortex filament structures not previously studied. We find that the solution structure progresses from planar to helical, and then to more intricate and complex filament structures, possibly indicating the onset of superfluid turbulence.

  19. Mate-searching behaviour of common and rare wasps and the implications for pollen movement of the sexually deceptive orchids they pollinate.

    PubMed

    Menz, Myles H M; Phillips, Ryan D; Dixon, Kingsley W; Peakall, Rod; Didham, Raphael K

    2013-01-01

    Pollinator behaviour directly affects patterns of pollen movement and outcrossing rates in plants. In orchids pollinated by sexual deception of insects, patterns of pollen movement are primarily determined by the mate-searching behaviour of the deceived males. Here, using a capture-mark-recapture study (CMR) and dietary analysis, we compare mate-searching behaviour in relation to local abundance of two pollinator species and explore the implications for pollen movement in sexually deceptive Drakaea (Orchidaceae). Drakaea are pollinated solely by the sexual deception of male thynnine wasps. The rare Drakaea elastica and widespread D. livida occur sympatrically and are pollinated by the rare but locally common Zaspilothynnus gilesi, and the widespread and abundant Z. nigripes, respectively. Local abundance was significantly different with Z. nigripes twice as abundant as Z. gilesi. For the 653 marked wasps, there was no significant difference in median movement distance between Z. gilesi and Z. nigripes. However, the maximum movement distance was twice as high for Z. gilesi (556 m) compared with Z. nigripes (267 m). This is up to three times greater than previously reported for thynnines in CMR studies. Recapture rates were six times higher in Z. gilesi (57%) compared to Z. nigripes (9%). Pollen loads and wasp longevity were similar, suggesting that this difference in recapture rate arises due to differences in the number of males moving at a scale >500 m rather than through diet or mortality. Differences in the frequency of longer movements may arise due to variation in the spatial distribution of the wingless females. We predict that pollen movement will largely be restricted to within populations of Drakaea (<500 m), with few movements between populations (>500 m).

  20. Elastin Fiber Accumulation in Liver Correlates with the Development of Hepatocellular Carcinoma

    PubMed Central

    Kurosaki, Masayuki; Higuchi, Mayu; Komiyama, Yasuyuki; Yoshida, Tsubasa; Hayashi, Tsuguru; Kuwabara, Konomi; Takaura, Kenta; Nakakuki, Natsuko; Takada, Hitomi; Tamaki, Nobuharu; Suzuki, Shoko; Nakanishi, Hiroyuki; Tsuchiya, Kaoru; Itakura, Jun; Takahashi, Yuka; Hashiguchi, Akinori; Sakamoto, Michiie; Izumi, Namiki

    2016-01-01

    Background & Aims The fibrosis stage, which is evaluated by the distribution pattern of collagen fibers, is a major predictor for the development of hepatocellular carcinoma (HCC) for patients with hepatitis C. Meanwhile, the role of elastin fibers has not yet been elucidated. The present study was conducted to determine the significance of quantifying both collagen and elastin fibers. Methods We enrolled 189 consecutive patients with hepatitis C and advanced fibrosis. Using Elastica van Gieson-stained whole-slide images of pretreatment liver biopsies, collagen and elastin fibers were evaluated pixel by pixel (0.46 μm/pixel) using an automated computational method. Consequently, fiber amount and cumulative incidences of HCC within 3 years were analyzed. Results There was a significant correlation between collagen and elastin fibers, whereas variation in elastin fiber was greater than in collagen fiber. Both collagen fiber (p = 0.008) and elastin fiber (p < 0.001) were significantly correlated with F stage. In total, 30 patients developed HCC during follow-up. Patients who have higher elastin fiber (p = 0.002) in addition to higher collagen fiber (p = 0.05) showed significantly higher incidences of HCC. With regard to elastin fiber, this difference remained significant in F3 patients. Furthermore, for patients with a higher collagen fiber amount, higher elastin was a significant predictor for HCC development (p = 0.02). Conclusions Computational analysis is a novel technique for quantification of fibers with the added value of conventional staging. Elastin fiber is a predictor for the development of HCC independently of collagen fiber and F stage. PMID:27128435

  1. Histological changes in canine aorta 1 year after stent-graft implantation: implications for the long-term stability of device anchoring zones.

    PubMed

    Bashar, Abul Hasan Muhammad; Kazui, Teruhisa; Terada, Hitoshi; Suzuki, Kazuya; Washiyama, Naoki; Yamashita, Katsushi; Baba, Satoshi

    2002-06-01

    To examine aortic histology 1 year after stent-graft implantation in a canine model as a means of assessing the durability of endograft fixation. Fourteen mongrel dogs each received 1 stent-graft and 1 bare stent placed endoluminally in the abdominal aorta. Eight animals were followed for 1 year, 3 for 4 to 8 weeks, and the remaining 3 for 24 to 48 hours. Aortic specimens were stained with hematoxylin-eosin, elastica-van Gieson, and Masson's trichrome and examined with light and electron microscopy and immunohistochemistry to identify smooth muscle cells (SMC), endothelialization, aortic wall ultrastructure, and changes at the device anchoring sites. No dilatation or dissection was noted at any of the device anchoring sites. The aortic media at 1 year was remarkably decreased in thickness: 891 +/- 196 microm in the control tissue versus 388 +/- 70 microm for the proximal stent-grafted aorta and 457 +/- 148 microm for the bare-stented aortic segment. Other important histological features were reduced elastic lamellae in the stent-grafted aorta versus control (p<0.0001), increased SMC density in the stent-grafted aortic region (p<0.0001 versus control), and absence of inflammatory infiltrate. Complete neointimal covering and endothelialization of the luminal endograft surface were found. SMCs generally showed no ultrastructural features of necrosis. Aortic stent-grafts induce distinctive histological changes in the aortic wall at 1 year, even when implanted in a healthy aorta. Although there is considerable medial elastin loss, an increased medial SMC density, an exuberant neointima, and a general absence of perigraft inflammation suggest an ongoing process of structural restoration at the device anchoring sites.

  2. A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

    NASA Astrophysics Data System (ADS)

    Abel, Julianna; Luntz, Jonathan; Brei, Diann

    2012-08-01

    Active knits are a unique architectural approach to meeting emerging smart structure needs for distributed high strain actuation with simultaneous force generation. This paper presents an analytical state-based model for predicting the actuation response of a shape memory alloy (SMA) garter knit textile. Garter knits generate significant contraction against moderate to large loads when heated, due to the continuous interlocked network of loops of SMA wire. For this knit architecture, the states of operation are defined on the basis of the thermal and mechanical loading of the textile, the resulting phase change of the SMA, and the load path followed to that state. Transitions between these operational states induce either stick or slip frictional forces depending upon the state and path, which affect the actuation response. A load-extension model of the textile is derived for each operational state using elastica theory and Euler-Bernoulli beam bending for the large deformations within a loop of wire based on the stress-strain behavior of the SMA material. This provides kinematic and kinetic relations which scale to form analytical transcendental expressions for the net actuation motion against an external load. This model was validated experimentally for an SMA garter knit textile over a range of applied forces with good correlation for both the load-extension behavior in each state as well as the net motion produced during the actuation cycle (250% recoverable strain and over 50% actuation). The two-dimensional analytical model of the garter stitch active knit provides the ability to predict the kinetic actuation performance, providing the basis for the design and synthesis of large stroke, large force distributed actuators that employ this novel architecture.

  3. Color correction for automatic fibrosis quantification in liver biopsy specimens

    PubMed Central

    Murakami, Yuri; Abe, Tokiya; Hashiguchi, Akinori; Yamaguchi, Masahiro; Saito, Akira; Sakamoto, Michiie

    2013-01-01

    Context: For a precise and objective quantification of liver fibrosis, quantitative evaluations through image analysis have been utilized. However, manual operations are required in most cases for extracting fiber areas because of color variation included in digital pathology images. Aims: The purpose of this research is to propose a color correction method for whole slide images (WSIs) of Elastica van Gieson (EVG) stained liver biopsy tissue specimens and to realize automated operation of image analysis for fibrosis quantification. Materials and Methods: Our experimental dataset consisted of 38 WSIs of liver biopsy specimens collected from 38 chronic viral hepatitis patients from multiple medical facilities, stained with EVG and scanned at ×20 using a Nano Zoomer 2.0 HT (Hamamatsu Photonics K.K., Hamamatsu, Japan). Color correction was performed by modifying the color distribution of a target WSI so as to fit to the reference, where the color distribution was modeled by a set of two triangle pyramids. Using color corrected WSIs; fibrosis quantification was performed based on tissue classification analysis. Statistical Analysis Used: Spearman's rank correlation coefficients were calculated between liver stiffness measured by transient elastography and median area ratio of collagen fibers calculated based on tissue classification results. Results: Statistical analysis results showed a significant correlation r = 0.61-0.68 even when tissue classifiers were trained by using a subset of WSIs, while the correlation coefficients were reduced to r = 0.40-0.50 without color correction. Conclusions: Fibrosis quantification accompanied with the proposed color correction method could provide an objective evaluation tool for liver fibrosis, which complements semi-quantitative histologic evaluation systems. PMID:24524002

  4. Three-dimensional multilayers of smooth muscle cells as a new experimental model for vascular elastic fiber formation studies.

    PubMed

    Ishiwata, Ryo; Yokoyama, Utako; Matsusaki, Michiya; Asano, Yoshiya; Kadowaki, Koji; Ichikawa, Yasuhiro; Umemura, Masanari; Fujita, Takayuki; Minamisawa, Susumu; Shimoda, Hiroshi; Akashi, Mitsuru; Ishikawa, Yoshihiro

    2014-04-01

    Elastic fiber formation is disrupted with age and by health conditions including aneurysms and atherosclerosis. Despite considerable progress in the understanding of elastogenesis using the planar culture system and genetically modified animals, it remains difficult to restore elastic fibers in diseased vessels. To further study the molecular mechanisms, in vitro three-dimensional vascular constructs need to be established. We previously fabricated vascular smooth muscle cells (SMCs) into three-dimensional cellular multilayers (3DCMs) using a hierarchical cell manipulation technique, in which cells were coated with fibronectin-gelatin nanofilms to provide adhesive nano-scaffolds. Since fibronectin is known to assemble and activate elastic fiber-related molecules, we further optimized culture conditions. Elastica stain, immunofluorescence, and electron microscopic analysis demonstrated that 3DCMs, which consisted of seven layers of neonatal rat aortic SMCs cultured in 1% fetal bovine serum (FBS) in Dulbecco's modified Eagle's medium, exhibited layered elastic fibers within seven days of being in a static culture condition. In contrast, the application of adult SMCs, 10% FBS, ε-poly(lysine) as an alternative adhesive for fibronectin, or four-layered SMCs, failed to generate layered elastic fiber formation. Radioimmunoassay using [(3)H]valine further confirmed the greater amount of cross-linked elastic fibers in 3DCMs than in monolayered SMCs. Layered elastic fiber formation in 3DCMs was inhibited by the lysyl oxidase inhibitor β-aminopropionitrile, or prostaglandin E2. Furthermore, infiltration of THP-1-derived macrophages decreased the surrounding elastic fiber formation in 3DCMs. 3DCMs may offer a new experimental vascular model to explore pharmacological therapeutic strategies for disordered elastic fiber homeostasis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Decreased elastic fibers and increased proteoglycans in the ligamentum flavum of patients with lumbar spinal canal stenosis.

    PubMed

    Yabe, Yutaka; Hagiwara, Yoshihiro; Tsuchiya, Masahiro; Honda, Masahito; Hatori, Kouki; Sonofuchi, Kazuaki; Kanazawa, Kenji; Koide, Masashi; Sekiguchi, Takuya; Itaya, Nobuyuki; Itoi, Eiji

    2016-07-01

    Elastic fibers and proteoglycans are major components of the extracellular matrix and their changes have been reported in some pathological conditions. Further, recent studies have indicated that some glycosaminoglycans and proteoglycans inhibit elastic fiber assembly. The purpose of this study was to investigate changes of the elastic fibers and proteoglycans in the ligamentum flavum and analyze their relationships to thickening of the ligamentum flavum from lumbar spinal canal stenosis (LSCS). Ligamentum flavum samples were collected from 20 patients with LSCS (thickened flavum group) and 10 patients with lumbar disc herniation (non-thickened flavum group) as a control. Elastica-Masson staining and alcian blue staining were used to compare the relationship between the changes in the elastic fibers and proteoglycans. Gene and protein expressions of the elastic fibers and proteoglycans were analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Histological changes indicated that proteoglycans mainly increased on the dorsal side of the ligamentum flavum in accordance with the decreased elastic fibers in the thickened flavum group. The gene and protein expressions of fibrillin-2 and DANCE were significantly lower and decorin, lumican, osteoglycin, and versican were significantly higher in the thickened flavum group. Our study shows that elastic fibers decrease and proteoglycans increase in the thickened ligamentum flavum. Decreased gene expression of elastogenesis and disrupted elastic fiber assembly caused by increased proteoglycans may lead to a loss of elasticity in the thickened ligamentum flavum. Decreased elasticity may cause buckling of the tissue, which leads to thickening of the ligamentum flavum. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1241-1247, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  6. Nd:YAG Laser Treatment of Keloids and Hypertrophic Scars

    PubMed Central

    Akaishi, Satoshi; Koike, Sachiko; Dohi, Teruyuki; Kobe, Kyoko; Hyakusoku, Hiko; Ogawa, Rei

    2012-01-01

    Pathological cutaneous scars such as keloids and hypertrophic scars (HSs) are characterized by a diffuse redness that is caused by the overgrowth of capillary vessels due to chronic inflammation. Our group has been using long-pulsed, 1064-nm Nd:YAG laser in noncontact mode with low fluence and a submillisecond pulse duration to treat keloids and hypertrophic scars since 2006 with satisfactory results. The present study examined the efficacy of this approach in 22 Japanese patients with keloids (n = 16) or hypertrophic scars (n = 6) who were treated every 3 to 4 weeks. Treatment settings were as follows: 5 mm spot size diameter; 14 J/cm2 energy density; 300 μs exposure time per pulse; and 10 Hz repetition rate. The responses of the pathological scars to the treatment were assessed by measuring their erythema, hypertrophy, hardness, itching, and pain or tenderness. Moreover, skin samples from 3 volunteer patients were subjected to histological evaluation and 5 patients underwent thermography during therapy. The average total scar assessment score dropped from 9.86 to 6.34. Hematoxylin and eosin staining and Elastica Masson-Goldner staining showed that laser treatment structurally changed the tissue collagen. This influence reached a depth of 0.5 to 1 mm. Electron microscopy revealed plasma protein leakage, proteoglycan particles, and a change in the collagen fiber fascicles. Further analyses revealed that noncontact mode Nd:YAG laser treatment is highly effective for keloids and hypertrophic scars regardless of patient age, the origin and multiplicity of scarring, the location of the scar(s), or the tension on the scar. PMID:22259645

  7. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    PubMed

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

  8. Long-term animal implantation study of biotube-autologous small-caliber vascular graft fabricated by in-body tissue architecture.

    PubMed

    Watanabe, Taiji; Kanda, Keiichi; Yamanami, Masashi; Ishibashi-Ueda, Hatsue; Yaku, Hitoshi; Nakayama, Yasuhide

    2011-07-01

    A mold for the preparation of an in-body tissue architecture-induced autologous vascular graft, termed "biotube," was prepared by covering a main silicone rod (outer diameter, 3 mm; length, 30 mm) with two pieces of polyurethane sponge tubes (internal diameter, 3 mm; length, 3 mm) at both ends. The molds were embedded into the dorsal subcutaneous pouch of rabbits (weighing ca. 2 kg) for 2 months. After harvesting the rods with the formed surrounding tissues, the rods were removed to create biotubes impregnated with anastomotic reinforcement cuffs at both ends. The biotubes had homogeneous, thin connective tissue wall (thickness, 76 ± 37 μm) that was primarily composed of collagen and fibroblasts. One biotube was loaded with argatroban and autoimplanted in the carotid artery for 26 months. Neither antiplatelet nor anticoagulant agents were administered, except for an intraoperative heparin injection. Follow-up angiography showed no aneurysm formation, rupturing, or stenosis during implantation. At the end of implantation, the wall thickness of biotube (212 ± 24 μm at the anastomosis portion and 150 ± 14 μm at the midportion) was similar to that of native artery (189 ± 23 μm). The luminal surface was completely covered with endothelial cells on the formed lamina elastica interna-like layer. The regenerated vascular walls comprised multilayered smooth muscle cells and dense collagen fibers with regular circumferential orientation. A remarkable multilayered elastin fiber network was observed near the anastomosis portion. Biotubes could thus be used as small-caliber vascular prostheses that greatly facilitate the healing process and exhibit excellent biocompatibility. Copyright © 2011 Wiley Periodicals, Inc.

  9. Determination of optimal rehydration, fixation and staining methods for histological and immunohistochemical analysis of mummified soft tissues.

    PubMed

    Mekota, A-M; Vermehren, M

    2005-01-01

    During an excavation headed by the German Institute for Archaeology, Cairo, at the tombs of the nobles in Thebes-West, Upper Egypt, three types of tissues from different mummies were sampled to compare 13 well known rehydration methods for mummified tissue with three newly developed methods. Furthermore, three fixatives were tested with each of the rehydration fluids. Meniscus (fibrocartilage), skin, and a placenta were used for this study. The rehydration and fixation procedures were uniform for all methods. The stains used were standard hematoxylin and eosin, elastica van Gieson, periodic acid-Schiff, and Grocott, and five commercially obtained immunohistochemical stains including pancytokeratin, vimentin, alpha-smooth-muscle-actin, basement membrane collagen type IV, and S-100 protein. The sections were examined by transmitted light microscopy. Our study showed that preservation of the tissue is dependent on the quality and effectiveness of the combination of the rehydration and fixation solutions, and that the quality of the histological and histochemical stains is dependent on the tissue quality. In addition, preservation of the antigens in the tissues is dependent on tissue quality, and fungal permeation had no influence on the tissue. Finally, the results are tissue specific. For placenta the best solution combination was Sandison and solution III (both fixed with formaldehyde) while results for skin were best with Ruffer I (using formaldehyde and Schaffer as fixatives), Grupe et al. (using formaldehyde as a fixative) and solution III (in combination with formaldehyde and Bouin fixatives). Ruffer II (using formaldehyde as a fixative) and solution III (in combination with Schaffer fixative) gave the best results for fibrocartilage.

  10. Mate-Searching Behaviour of Common and Rare Wasps and the Implications for Pollen Movement of the Sexually Deceptive Orchids They Pollinate

    PubMed Central

    Menz, Myles H. M.; Phillips, Ryan D.; Dixon, Kingsley W.; Peakall, Rod; Didham, Raphael K.

    2013-01-01

    Pollinator behaviour directly affects patterns of pollen movement and outcrossing rates in plants. In orchids pollinated by sexual deception of insects, patterns of pollen movement are primarily determined by the mate-searching behaviour of the deceived males. Here, using a capture-mark-recapture study (CMR) and dietary analysis, we compare mate-searching behaviour in relation to local abundance of two pollinator species and explore the implications for pollen movement in sexually deceptive Drakaea (Orchidaceae). Drakaea are pollinated solely by the sexual deception of male thynnine wasps. The rare Drakaea elastica and widespread D. livida occur sympatrically and are pollinated by the rare but locally common Zaspilothynnus gilesi, and the widespread and abundant Z. nigripes, respectively. Local abundance was significantly different with Z. nigripes twice as abundant as Z. gilesi. For the 653 marked wasps, there was no significant difference in median movement distance between Z. gilesi and Z. nigripes. However, the maximum movement distance was twice as high for Z. gilesi (556 m) compared with Z. nigripes (267 m). This is up to three times greater than previously reported for thynnines in CMR studies. Recapture rates were six times higher in Z. gilesi (57%) compared to Z. nigripes (9%). Pollen loads and wasp longevity were similar, suggesting that this difference in recapture rate arises due to differences in the number of males moving at a scale >500 m rather than through diet or mortality. Differences in the frequency of longer movements may arise due to variation in the spatial distribution of the wingless females. We predict that pollen movement will largely be restricted to within populations of Drakaea (<500 m), with few movements between populations (>500 m). PMID:23536860

  11. Histochemical and immunohistochemical examination of odontoblasts (petroblasts) in petrodentine formation of lungfish.

    PubMed

    Oka, Shunya; Sasagawa, Ichiro; Ishiyama, Mikio

    2017-11-01

    Petrodentine, the core of the lungfish tooth plate, is a well-mineralized tissue similar to mammalian enamel and analogous to enameloid in fish teeth. Petrodentine is formed solely by petroblasts, which are specialized odontoblasts, whereas enameloid is a composite tissue produced by both odontoblasts and dental epithelial cells. To clarify the details of petrodentine formation, petroblasts were investigated using histochemical and immunohistochemical techniques. Extant lungfish (Lepidosiren paradoxa) were used in this study. Tooth plates during the stage of petrodentine formation were observed by means of histochemistry and immunohistochemistry. Commercial kits were used to detect enzyme activity. Correlative sections were immunostained using antibodies against selected peptides. Routine staining such as periodic acid-Schiff (PAS) reaction to identify glycogen and Elastica van Gieson staining for the detection of elastic fibers in histological sections were performed. In addition, conventional transmission electron microscopy was used for observing the fine structure. Petroblasts showed marked acid and alkaline phosphatase activities, and positive immunoreactivities against anti-nestin, anti-V-ATPase, and anti-Ca(2+)-ATPase, during the maturation stage, but in the matrix formation stage, reactions were much weaker than that of the maturation stage. During the maturation stage, petroblasts showed intense PAS reactivity, and glycogen particles were observed in petroblasts by transmission electron microscopy. Glucose transporter 1-immunoreactivity was observed in petroblasts in the matrix formation stage and the initial to mid part of the maturation stage. The results in this study suggested that petroblasts have two functional stages, matrix formation and maturation, and glycogen plays an important role in the modulation of petroblasts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Deletion of hypoxia-inducible factor-1α in myeloid lineage exaggerates angiotensin II-induced formation of abdominal aortic aneurysm.

    PubMed

    Takahara, Yusuke; Tokunou, Tomotake; Kojima, Hiroshi; Hirooka, Yoshitaka; Ichiki, Toshihiro

    2017-04-01

    Hypoxia-inducible factor (HIF)-1α is a transcription factor that regulates various genes responding to hypoxic conditions. We previously reported that myeloid-specific activation of HIF-1α had protective effects on hypertensive cardiovascular remodelling in mice. However the role of myeloid lineage HIF-1α in the development of abdominal aortic aneurysm (AAA) has not been determined. Myeloid-specific HIF-1α knockout (HIF-1KO) mice were created using a Cre-lox recombination system in the background of apolipoprotein E-deficient (ApoE(-/-)) mice. HIF-1KO and control mice were fed high-fat diet (HFD) and infused with angiotensin II (Ang II, 1800 ng/kg/min) by an osmotic mini pump for 4 weeks to induce AAA formation. Deletion of HIF-1α increased aortic external diameter (2.47±0.21 mm versus 1.80±0.28 mm in control, P=0.035). AAA formation rate (94.4% in HIF-1KO versus 81.8% in control) was not statistically significant. Elastic lamina degradation grade determined by Elastica van Gieson (EVG) staining was deteriorated in HIF-1KO mice (3.91±0.08 versus 3.25±0.31 in control, P=0.013). The number of infiltrated macrophages into the abdominal aorta was increased in HIF-1KO mice. Expression of tissue inhibitors of metalloproteinases (TIMPs) was suppressed in the aorta and peritoneal macrophages (PMs) from HIF-1KO mice compared with control mice. HIF-1α in myeloid lineage cells may have a protective role against AAA formation induced by Ang II and HFD in ApoE(-/-) mice.

  13. Decreased Neointimal Extracellular Matrix Formation in RAGE-Knockout Mice After Microvascular Denudation

    SciTech Connect

    Groezinger, Gerd Schmehl, Joerg Bantleon, Ruediger Kehlbach, Rainer; Mehra, Tarun; Claussen, Claus Wiesinger, Benjamin

    2012-12-15

    Purpose: To evaluate in vivo the role of RAGE (receptor for advanced glycated end products) in the development of restenosis and neointimal proliferation in RAGE-deficient knockout (KO) mice compared with wild-type (WT) mice in an animal model. Materials and Methods: Sixteen WT and 15 RAGE-deficient mice underwent microvascular denudation of the common femoral artery under general anaesthesia. Contralateral arteries underwent a sham operation and served as controls. Four weeks after the intervention, all animals were killed, and paraformaldehyde-fixed specimens of the femoral artery were analysed with different stains (hematoxylin and eosin and Elastica van Gieson) and several different types of immunostaining (proliferating cell nuclear antigen, {alpha}-actin, collagen, von Willebrand factor, RAGE). Luminal area, area of the neointima, and area of the media were measured in all specimens. In addition, colony-formation assays were performed, and collagen production by WT smooth muscle cells (SMCs) and RAGE-KO SMCs was determined. For statistical analysis, P < 0.05 was considered statistically significant. Results: Four weeks after denudation, WT mice showed a 49.6% loss of luminal area compared with 14.9% loss of luminal area in RAGE-deficient mice (sham = 0% loss) (P < 0.001). The neointima was 18.2 (*1000 {mu}m{sup 2} [n = 15) in the WT group compared with only 8.4 (*1000 {mu}m{sup 2} [n = 16]) in the RAGE-KO group. RAGE-KO SMCs showed significantly decreased proliferation activity and production of extracellular matrix protein. Conclusion: RAGE may be shown to play a considerable role in the formation of neointima leading to restenosis after vascular injury.

  14. Response to dietary tannin challenges in view of the browser/grazer dichotomy in an Ethiopian setting: Bonga sheep versus Kaffa goats.

    PubMed

    Yisehak, Kechero; Kibreab, Yoseph; Taye, Tolemariam; Lourenço, Marta Ribeiro Alves; Janssens, Geert Paul Jules

    2016-01-01

    It has been suggested that goats (typical browser) are better adapted to digest tannin-rich diets than sheep (typical grazer). To evaluate this, Bonga sheep and Kaffa goats were used in a 2 × 3 randomized crossover design with two species, three diets, and three periods (15-day adaptation + 7-day collection). The dietary treatments consisted of grass-based hay only (tannin-free diet = FT), a high-tannin diet (36% Albizia schimperiana (AS) + 9% Ficus elastica (FE) + 55% FT (HT)), and HT + polyethylene glycol 6000 (PEG). Animals were individually fed at 50 g dry matter (DM)/kg body weight (BW) and had free access to clean drinking water and mineralized salt licks. Nutrient intake, apparent nutrient digestibility, nutrient conversion ratios, and live weight changes were determined. Condensed tannin concentrations in AS and FE were 110 and 191 g/kg DM, respectively. Both sheep and goats ate 47% more of HT than FT, and dry matter intake further increased by 9% when PEG was added, with clear difference in effect size between goats and sheep (P < 0.001). The effects of the tannin-rich diet and PEG addition were similarly positive for DM digestibility between sheep and goats, but crude protein (CP) digestibility was higher in HT + PEG-fed goats than in sheep fed the same diet. However, PEG addition induced a larger improvement in growth performance and feed efficiency ratio in sheep than in goat (P < 0.001). The addition of PEG as a tannin binder improved digestion and performance in both species, but with the highest effect size in sheep.

  15. Pathological findings of saccular cerebral aneurysms-impact of subintimal fibrin deposition on aneurysm rupture.

    PubMed

    Hokari, Masaaki; Nakayama, Naoki; Nishihara, Hiroshi; Houkin, Kiyohiro

    2015-07-01

    Although several studies have suggested that aneurysmal wall inflammation and laminar thrombus are associated with the rupture of saccular aneurysms, the mechanisms leading to the rupture remain obscure. We performed full exposure of aneurysms before clip application and attempted to keep the fibrin cap on the rupture point. Using these specimens in a nearly original state before surgery, we conducted a pathological analysis and studied the differences between ruptured and unruptured aneurysms to clarify the mechanism of aneurysmal wall degeneration. This study included ruptured (n = 28) and unruptured (n = 12) saccular aneurysms resected after clipping. All of the ruptured aneurysms were obtained within 24 h of onset. Immunostainings for markers of inflammatory cells (CD68) and classical histological staining techniques were performed. Clinical variables and pathological findings from ruptured and unruptured aneurysms were compared. Patients with ruptured or unruptured aneurysms did not differ by age, gender, size, location, and risk factors, such as hypertension, smoking, and hyperlipidemia. The absence or fragmentation of the internal elastica lamina, the myointimal hyperplasia, and the thinning of the aneurysmal wall were generally observed in both aneurysms. The existence of subintimal fibrin deposition, organized laminar thrombus, intramural hemorrhage, neovascularization, and monocyte infiltration are more frequently observed in ruptured aneurysms. Multivariate logistic regression analysis showed that ruptured aneurysm was associated with presence of subintimal fibrin deposition and monocyte infiltration. These findings suggest that subintimal fibrin deposition and chronic inflammation have a strong impact on degeneration of the aneurysmal wall leading to their rupture, and this finding may be caused by endothelial dysfunction.

  16. [An animal experiment study on the effect of periodontitis on atherosclerosis].

    PubMed

    Wang, Zhou; Zhang, Mingzhu; Yu, Zhuo; Shui, Yanqing; Ding, Yun; Lei, Yayan

    2012-06-01

    To make an animal periodontitis and atherosclerosis compound model, and to study the effects of periodontitis on atherosclerosis. 36 Japan rabbits were randomly divided into four groups: Including periodontitis model group, periodontitis and atherosclerosis compound model group, atherosclerosis model group and control group. Periodontitis model was initiated by ligating floss around teeth cervical and oral inoculating with Porphyromonas gingivalis (P. gingivalis). Atherosclerosis was established by single iliac artery of balloon-injured rabbit. Histopathological change of injured iliac artery was observed under optical microscope after hematoxylin-eosion stain. Elastica van Gieson-stained sections were used for the morphometric analysis. We measured intimal and medial lesion areas in iliac artery cross-sections as well as the intimal/medial ratio (I/M). We also analyzed P. gingivalis 16S rDNA amplification with nested-polymerase chain reaction (nested-PCR), and detect systemic proinflammatory mediators with enzyme linked immunosorbent assay (ELISA), including C-reactive protein (CRP), interleukin-6 (IL-6) and interleukin-1beta (IL-1beta). The serum levels of CRP, IL-6 and IL-1beta increased obviously among the compound model group than other groups (P<0.01). Histopathological observation revealed the compound model group in I/M was bigger than other groups (P<0.01). P. gingivalis 16S rDNA was detected among the periodontitis model group and the compound model group by nested-PCR. Periodontitis may accelerate intimal hyperplasia in balloon-injured iliac arteries by upgrade of systemic inflammation factors and local bacterial infection.

  17. The looped adhesive strip: An example of coplanar delamination interaction

    NASA Technical Reports Server (NTRS)

    Bottega, W. J.

    1990-01-01

    The phenomenon of peeling and debonding of thin layers is a subject of interest to those concerned with adhesives, thin films, and layered materials. In recent years much attention has been focused on such problems as a result of increased interest and application of advanced composites and thin film coatings. A related problem which is of interest for its own sake but also represents a simple example of a tangled adhesive strip and of coplanar delamination interaction, is the problem of a looped adhesive strip. This is the subject of the present study. Researchers consider here the problem of an elastic strip which possesses an adherend on (at least) one of its surfaces. If the strip is deformed so that two portions of such a surface are brought into contact, a position of the strip becomes bonded and a loop is formed. Researchers are interested in determining the equilibrium configuration of such a strip and investigating the behavior of the strip when its edges are pulled apart. The problem is approached as a moving interior boundary problem in the calculus of variations with the strip modeled as an inextensible elastica and the bond strength characterized by its surface energy. A Griffith type energy criterion is employed for debonding, and solutions corresponding to the problem of interest obtained. The solution obtained will be seen to predict the interesting phenomenon of bond point propagation, as well as the more standard peeling type behavior. Numerical results demonstrating the phenomena of interest are presented as well and will be seen to reveal both stable and unstable propagation of the boundaries of the bonded portion of the strip, depending upon the loading conditions.

  18. Impact of the Timing of Morphine Administration on Lipopolysaccharide-Mediated Lethal Endotoxic Shock in Mice.

    PubMed

    Fukada, Tomoko; Kato, Hidehito; Ozaki, Makoto; Yagi, Junji

    2016-05-01

    Sepsis is a serious condition related to systemic inflammation, organ dysfunction, and organ failure. It is a subset of the cytokine storm caused by dysregulation of cytokine production. Morphine influences the severity of infection in vivo and in vitro because it regulates cytokine production. We investigated the immunological function of morphine using a mouse model of septic shock. We treated mice with α-galactosylceramide (2 μg/mouse) to induce lethal endotoxic shock following a challenge with lipopolysaccharide (LPS, 1.5 μg/mouse). This model represents acute lung injury and respiratory failure, and reflects the clinical features of severe septic shock. We evaluated the effect of the timing of morphine (0.8 mg/mouse) administration on the survival rate, cytokine production in vivo, and histological changes of mice with LPS-mediated lethal endotoxic shock. Morphine treatment before LPS challenge suppressed lethal endotoxic shock. In contrast, when we administered after LPS, morphine exacerbated lethal endotoxic shock; hematoxylin and eosin staining revealed a marked increase in the accumulation of infiltrates comprising polymorphonuclear leukocytes and mononuclear cells in the lung; and Elastica van Gieson staining revealed the destruction of alveoli. The plasma levels of tumor necrosis factor-α, interferon-γ, monocyte-chemotactic protein-1, and interleukin-12 in the group treated with morphine after LPS challenge were higher than those treated with morphine before LPS challenge. In conclusion, one of the factors that determine whether morphine exacerbates or inhibits infection is the timing of its administration. Morphine treatment before shock improved the survival rate, and morphine treatment after shock decreased the rate of survival.

  19. The hemorrhage caused by sporadic-type cerebral amyloid angiopathy occurs primarily in the cerebral sulci.

    PubMed

    Takeda, Shigeki; Hinokuma, Kaoru; Yamazaki, Kazunori; Onda, Kiyoshi; Miyakawa, Teruo; Ikuta, Fusahiro; Arai, Hiroyuki

    2012-02-01

    We examined a solitary hematoma in a patient with sporadic cerebral amyloid angiopathy (CAA). The hematoma affected the middle frontal sulcus, cerebral cortex (CC) and subcortical frontal white matter (sfWM). We embedded the hematoma in four paraffin blocks, each of which was cut serially into 6-µm-thick sections. The first section and every 18th section from each block were subjected to Elastica-Goldner (E-G) staining, and the distribution and diameter of the ruptured blood vessels (rBVs) were examined. The rBVs were then marked on diagrams representing each E-G-stained section. The present study yielded the following important findings: (i), early- and recently ruptured Aβ-positive arteries were present mainly in the intrasulcal hematoma (ISH), rather than in the CC; (ii) many early-ruptured arteries in the ISH were larger in diameter than those in the CC; and (iii) ruptures of the cortical arteries, even near the cortical surface, did not occur so frequently and the ruptured vessels were small in size. We concluded that in patients with subcortical hematoma caused by sporadic-type CAA, successive rupturse of the meningeal vessels, mainly arteries, occur in the cerebral sulcus initially, followed by formation of an ISH and development of a fresh hemorrhagic or anemic infarct in the CC surrounding the ISH, the latter in most cases then extending into the brain parenchyma through the necrotic CC at the depth of the sulcus, finally creating a secondary hematoma in the subcortical white matter. © 2011 Japanese Society of Neuropathology.

  20. Changes of Spleen in Wistar Rats Exposed to Therapeutic Doses of Dexamethasone and Medroxyprogesterone Acetate Evaluated by Stereological Parameters.

    PubMed

    Mitevska, Elida; Kostadinova-Petrova, Irena; Kostovska, Nevena

    2015-01-01

    The aim of our investigation was to evaluate the immunosuppressive effect of medroxyprogesterone acetate (MPA) determining the volume densities of the structural components of the spleen. The volume densities of the same structural components of spleen were determined after administration of dexamethasone too, in order to see whether the morphological changes induced by MPA are in the same line with the changes caused by dexamethasone. 60 female Wistar rats were divided into 5 groups. The control group of rats was administered physiological solution. The remaining, 4 experimental groups were administered: dexamethasone at a therapeutic daily dose of 0.6 mg/kg bw and maximal therapeutic dose of 3 mg/kg bw, and MPA at a therapeutic dose of 30 mg/kg bw and maximal therapeutic dose of 150 mg/kg bw. The drugs were applied intramuscularly for 7 days. Spleen paraffin sections were stained according to the methods: hematoxylin-eosin, Masson and Elastica van-Gieson. Stereological measurements were performed by using the Weibl's multipurpose test system (M-42). The histological analyses of the structural components of the spleen in rats treated with dexamethasone and MPA have shown reduction of the white pulp and the marginal zone and an apparent decrease of the cellular density of the lymphocyte component of the pulp. The stereological analysis of the spleen showed significant decrease of the splenic pulp volume density and significant increase of the connective tissue volume density. Reducing the presence of splenic pulp was mainly due to the decrease in the volume density of all structural components of the white pulp. Changes were observed in all drug treated groups of rats. Our results have shown that the MPA provoked changes suggested atrophy of the spleen lymphoid tissue. Although the atrophic changes of the spleen were significant after the application of both dexamethasone and MPA, the white pulp was significantly more sensitive substrate for dexamethasone than for

  1. A novel mouse model of high flow-induced pulmonary hypertension-surgically induced by right pulmonary artery ligation.

    PubMed

    Zhang, Anchen; Wang, Hongfei; Wang, Shengwei; Huang, Xiaofan; Ye, Ping; Du, Xinling; Xia, Jiahong

    2017-02-01

    This study sought to establish a new model of high-flow pulmonary hypertension (PH) in mice. This model may be useful for studies seeking to reduce the pulmonary vascular resistance and delay the development of PH caused by congenital heart disease. The right pulmonary artery was ligated via a right posterolateral thoracotomy. Pulmonary hemodynamics was evaluated by right heart catheterization immediately after ligation and at 2, 4, 8, and 12 wk postoperatively. The right ventricle (RV) and the left ventricle (LV) with septum (S) were weighed to calculate the RV/(LV + S) ratio as an index of right ventricular hypertrophy. Morphologic changes in the left lungs were analyzed, and percentages of muscularized pulmonary vessels were assessed by hematoxylin and eosin, elastica van Gieson and alpha-smooth muscle actin staining. All the study data were compared with data from a model of PH generated by hypoxic stimulation. A pulmonary hypertensive state was successfully induced by 2 wk after surgery. However, the morphologic analysis demonstrated that pulmonary vascular muscularization, as evaluated using right ventricular systolic pressure and RV/(LV + S), was not significantly increased until 4 wk postoperatively. When mice from the new model and the hypoxic model were compared, no significant differences were observed in any of the evaluated indices. High-flow PH can be induced within 4 wk after ligation of the right pulmonary artery, which is easily performed in mice. Such mice can be used as a model of high-flow PH. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Snakebites and ethnobotany in the northwest region of Colombia. Part III: neutralization of the haemorrhagic effect of Bothrops atrox venom.

    PubMed

    Otero, R; Núñez, V; Barona, J; Fonnegra, R; Jiménez, S L; Osorio, R G; Saldarriaga, M; Díaz, A

    2000-11-01

    Thirty-one of 75 extracts of plants used by traditional healers for snakebites, had moderate or high neutralizing ability against the haemorrhagic effect of Bothrops atrox venom from Antioquia and Chocó, north-western Colombia. After preincubation of several doses of every extract (7.8-4000 microg/mouse) with six minimum haemorrhagic doses (10 microg) of venom, 12 of them demonstrated 100% neutralizing capacity when the mixture was i.d. injected into mice (18-20 g). These were the stem barks of Brownea rosademonte (Caesalpiniaceae) and Tabebuia rosea (Bignoniaceae); the whole plants of Pleopeltis percussa (Polypodiaceae), Trichomanes elegans (Hymenophyllaceae) and Senna dariensis (Caesalpiniaceae); rhizomes of Heliconia curtispatha (Heliconiaceae); leaves and branches of Bixa orellana (Bixaceae), Philodendron tripartitum (Araceae), Struthanthus orbicularis (Loranthaceae) and Gonzalagunia panamensis (Rubiaceae); the ripe fruits of Citrus limon (Rutaceae); leaves, branches and stem of Ficus nymphaeifolia (Moraceae). Extracts of another 19 species showed moderate neutralization (21-72%) at doses up to 4 mg/mouse, e.g. the whole plants of Aristolochia grandiflora (Aristolochiaceae), Columnea kalbreyeriana (Gesneriaceae), Sida acuta (Malvaceae), Selaginella articulata (Selaginellaceae) and Pseudoelephantopus spicatus (Asteraceae); rhizomes of Renealmia alpinia (Zingiberaceae); the stem of Strychnos xinguensis (Loganiaceae); leaves, branches and stems of Hyptis capitata (Lamiaceae), Ipomoea cairica (Convolvulaceae), Neurolaena lobata (Asteraceae), Ocimum micranthum (Lamiaceae), Piper pulchrum (Piperaceae), Siparuna thecaphora (Monimiaceae), Castilla elastica (Moraceae) and Allamanda cathartica (Apocynaceae); the macerated ripe fruits of Capsicum frutescens (Solanaceae); the unripe fruits of Crescentia cujete (Bignoniaceae); leaves and branches of Piper arboreum (Piperaceae) and Passiflora quadrangularis (Passifloraceae). When the extracts were independently administered

  3. Mechanics of low-dimensional carbon nanostructures: Atomistic, continuum, and multi-scale approaches

    NASA Astrophysics Data System (ADS)

    Mahdavi, Arash

    collapsing approaches zero as the tube radius increases. We also demonstrate why collapse with a wide indenter may be difficult to observe in narrow tubes. A reduced-order model is developed for the dynamics of the carbon nanotube atomic force microscope probes. Bending behavior of the nanotube probe is modeled using Euler's elastica. A nonlinear moment-curvature relationship is implemeneted to account for the ovalization of the cross section of the nanotube during bending. Van der Waal forces acting between tube and the substrate is integrated over the surface of the tube and used as distributed follower forces acting on the equivalent elastica. Approximating the behavior of the nanotube with an elastica proved to be a very effiecient technique for modeling these nanostructures.

  4. Screening of metabolites secondary compounds in extract of moringa fruit and determination of inhibitory effect on growth of the fungus Candida albicans

    NASA Astrophysics Data System (ADS)

    Nuryanti, Siti; Puspitasari, Dwi Juli

    2017-08-01

    Moringa (Moringa oleifera Lamk) is a nutritious plant that can cure various diseases. Parts of this plant like leave, root, flower, and fruit can be used as a traditional medicine. The research about screening of secondary metabolites in moringa extracts and the determination of their inhibitory effect on growth of the fungus Candida albicans have been done. This research was conducted by extracting the moringa fruit with various solvent with different polarity namely hexane, distilled water and ethanol. The fungal inhibition test was done by well-difuse method. Suspensions of Candida albicans was standardized by 0.5 Mc Farland standard. The results showed that the extracts of Moringa with distilled water provided the greatest inhibition on the growth of the fungus Candida albicans compared to moringa fruit extracted by ethanol and hexane. The percentages inhibition of Moringa extracts on the growth of the Candida albicans with distilled water, ethanol and hexane solvents were 89.90%, 57.90% and 8.97% respectively. Phytochemical screening test showed that the moringa fruit contain alkaloids, flavonoids and steroids.

  5. Thermodynamic modeling and kinetics simulation of precipitate phases in AISI 316 stainless steels

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Busby, J. T.

    2014-05-01

    This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 °C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.

  6. Perfil de temperatura dos funis magnetosféricos de estrelas T Tauri com aquecimento alfvênico

    NASA Astrophysics Data System (ADS)

    Vasconcelos, M. J.

    2003-08-01

    Estrelas T Tauri Clássicas são objetos jovens circundados por discos de gás e poeira e que apresentam uma intensa atividade magnética. Seu espectro mostra linhas de emissão alargadas que são razoavelmente reproduzidas nos modelos de acresção magnetosférica. No entanto, o perfil de temperatura dos funis magnéticos é desconhecido. Aquecimento magnético compressional e difusão ambipolar foram considerados para estas estruturas, porém as temperaturas obtidas não são suficientes para explicar as observações. Neste trabalho, examinamos o aquecimento gerado pelo amortecimento de ondas Alfvén através de quatro mecanismos, os amortecimentos não-linear, turbulento, viscoso-resistivo e colisional como função da freqüência da onda. Inicialmente, a temperatura é ajustada para reproduzir as observações e o grau de turbulência requerido para que o mecanismo seja viável é calculado. Os resultados mostram que este é compatível com os dados observacionais. Apresentam-se, também, resultados preliminares do cálculo auto-consistente do perfil de temperatura dos funis, levando-se em conta fontes de aquecimento Alfvênica e fontes de resfriamento.

  7. Infratentorial angioleiomyoma: case report and review of the literature.

    PubMed

    Delgado-Fernandez, Juan; Penanes, Juan R; Torres, Cristina V; Gordillo-Velez, Carlos H; Manzanares-Soler, Rafael; Sola, Rafael G

    2016-01-16

    Introduccion. Los angioleiomiomas intracraneales son lesiones muy poco frecuentes. Solo se han descrito 22 casos en la bibliografia hasta la actualidad, unicamente tres de ellos de localizacion infratentorial. Caso clinico. Varon de 43 años con un angioleiomioma infratentorial descubierto de forma incidental tras la realizacion de una tomografia computarizada por hipoacusia. La resonancia magnetica mostro una tumoracion de 1,4 cm, descrita inicialmente como un meningioma, con un realce progresivo tras la administracion de gadolinio, un aumento del coeficiente de difusion aparente y un descenso generalizado de metabolitos en la espectroscopia. La lesion se reseco quirurgicamente mediante un abordaje suboccipital con buena evolucion y sin complicaciones postoperatorias. En el estudio histologico, la lesion presentaba un abundante componente vascular, y en la tincion inmunohistoquimica era positiva para actina y caldesmona. Dos años despues de la cirugia, el paciente no presentaba recurrencia en la resonancia magnetica de control. Conclusion. El diagnostico de los angioleiomiomas puede ser complejo, pero algunas de sus caracteristicas radiologicas pueden facilitarlo. Los angioleiomiomas son tumores benignos asociados con un resultado funcional favorable tras su reseccion completa, que en nuestro caso no presento un alto riesgo de sangrado.

  8. [Changes introduced into the recent International Classification of Headache Disorders: ICHD-III beta classification].

    PubMed

    Belvis, Robert; Mas, Natàlia; Roig, Carles

    2015-01-16

    Introduccion. La Sociedad Internacional de Cefaleas (IHS) ha publicado la tercera edicion de la Clasificacion Internacional de las Cefaleas (ICHD-III beta), la guia diagnostica de las cefaleas mas utilizada en el mundo. Objetivo. Revisar las recientes aportaciones de la guia, explicando las nuevas entidades que en ella aparecen y comparando las entidades que han matizado sus criterios con sus criterios de la edicion precedente. Desarrollo. Hemos registrado multitud de matices en los criterios de practicamente todas las cefaleas y neuralgias de la clasificacion, pero las entidades que han experimentado mas matizaciones trascendentales son la migraña cronica, la cefalea asociada exclusivamente a la actividad sexual, las cefaleas neuralgiformes unilaterales de breve duracion, la cefalea diaria persistente de novo, la cefalea por abuso de medicacion sintomatica, el sindrome de cefalea y deficits neurologicos transitorios con pleocitosis linfocitaria. Las entidades nuevas mas destacables que se han incorporado son las cefaleas por presion externa, las cefaleas por crioestimulo, la cefalea numular, la cefalea atribuida a vuelos de avion y la cefalea atribuida a disreflexia autonomica. Tambien cabe destacar las nuevas cefaleas, aun no consideradas como entidades, que se incorporan al apendice, entre las que destacan la epicranea fugax, la migraña vestibular y los colicos infantiles. Conclusiones. La IHS recomienda utilizar ya la nueva clasificacion (ICHD-III beta), prescindiendo de la anterior clasificacion, en la asistencia, la docencia y la investigacion, asi como hacer la maxima difusion de esta nueva guia.

  9. [Percutaneous cardiovascular intervention procedures in Brazil (1992-1993). Report of the National Registry-National Center for Cardiovascular Interventions].

    PubMed

    Sousa, A G

    1994-04-01

    To report the data on the first 2 years (1992-1993) of activity of the National Registry of Cardiovascular Interventions (CENIC) of the Hemodynamic and Angiography Department (DHA) of the Brazilian Society of Cardiology (SBC). The full members of the DHA of the SBC sent their data on seven types of interventions: balloon angioplasty (PTCA), mitral balloon valvoplasty (MBV), pulmonary balloon valvoplasty (PBV), aortic balloon valvoplasty (ABV), tricuspid balloon valvoplasty (TBV), aortic balloon dilation (AoB) and balloon dilation of pulmonary branches (PBB), to the CENIC. Ninety-seven interventional cardiologists and 71 hospitals in 14 states, participated in this data bank. During this time, 16,429 PTCA, 551 MBV, 347 PBV, 62 ABV, 61 AoB, 3 TBV and 3 PBB were registered. PTCA was therefore the most performed procedure (94%); primary success rate was 89.7%. As for the major complications, there were 2.5% acute myocardial infarction; 0.8% emergency bypass surgery and 1.8% death. As for the other interventions, the primary success rate was 92.9% for MBV, 88.5% for PBV, 80.3% for AoB, 72.6% for ABV, 66.7% for TBV with 0.54% deaths for MBV patients and 3.23% for ABV patients. The performance of the interventional cardiology in Brazil reflects the difusion of intervention methods in the main hospitals of the country. The results demonstrate a high efficacy and safety rate, characterizing an excellent performance.

  10. [Phenotypic and genotypic characterization of resistance to third-generation cephalosporins in Enterobacter spp].

    PubMed

    Bertona, E; Radice, M; Rodríguez, C H; Barberis, C; Vay, C; Famiglietti, A; Gutkind, G

    2005-01-01

    Enterobacter spp. are becoming increasingly frequent nosocomial pathogens with multiple resistance mechanism to beta-lactam antibiotics. We carried out the phenotypic and genotypic characterization of beta-lactamases in 27 Enterobacter spp. (25 Enterobacter cloacae y 2 Enterobacter aerogenes), as well as the ability of different extended spectrum-lactamase (ESBL) screening methods. Resistance to third generation cephalosporins was observed in 15/27 (63%) isolates. Twelve resistant isolates produced high level chromosomal encoded AmpC beta-lactamase; 6 of them were also producers of PER-2. Resistance to third generation cephalosporins in the remaining 3 isolates was due to the presence of ESBLs, PER-2 in 2 cases, and CTX-M-2 in the other. Only CTX-M-2 production was detected with all tested cephalosporins using difusion synergy tests, while cefepime improved ESBLs detection in 7/8 PER-2 producers, 4/8 in the inhibitor approximation test and 7/8 with double disk test using cefepime containing disk with and without clavulanic acid. Dilution method, including cephalosporins with and without the inhibitor detected 1/9 ESBLs producers.

  11. [Effects of penetration enhancers on in vitro percutaneous absorption and amount retained in skin of paeonol, dictamnine, fraxinellone and glycyrrhetinic acid in Liangfu cream].

    PubMed

    Wang, Sen; Zhu, Weifeng; Ou, Shuiping; Guan, Yongmeii; Chen, Lihua; Yang, Ming

    2009-07-01

    To study the effects of different penetration enhancers on the in vitro percutaneous absorption and amount retained in skin of active ingredients in Liangfu cream and to screen out the effective accelerator. Using improved Franz-type difusion cell and excised small mouse skin in vitro as transdermal barrier, the amount retained in skin and kinetics parameters of active ingredients such as cumulative permeation quantity, permeation rate and permeation lagged time were determined by HPLC. The enhancement ability of four different enhancers such as azone, oleic acid, transcutol P and isopropyl myristate were investigated. 3% IPM enhanced the cumulative permeation quantity better than other penetration enhancers. The enhancive permeation multiples of paeonol, dictamnine, fraxinellone and glycyrrhetinic acid were 1.52, 1.24, 1.73 and 3.21 times (P < 0.05). The enhancive amount retained in skin multiple of glycyrrhetinic acid was 1.96 times (P < 0.05), but for other components there were no significant impacts. The effects of penetration enhancers on the in vitro percutaneous absorption and amount retained in skin of components in Liangfu cream are different. 3% IPM which can enhance the cumulative permeation quantity of four components and amount retained in skin of glycyrrhetinic acid is the most suitable penetration enhancer for Liangfu cream.

  12. In vitro antibacterial effect of different irrigating solutions on Enterococcus faecalis.

    PubMed

    Bulacio, María de los Angeles; Cangemi, Rosa; Cecilia, Marta; Raiden, Guillermo

    2006-01-01

    Was evaluated the minimum inhibitory concentration (MIC) and the antibacterial effect (AE) of 2.5% NaOCl, 0.2% chlorhexidine gluconate (CHX) and 17% EDTA on Enterococcus faecalis. The antibacterial capacity was assessed by difusion in agar. The AE was evaluated on contaminated root dentin, employing apical and middle portions of human roots, sterilized and contaminated with Enterococcus faecalis, immersed in the irrigation solutions and incubated at 37 degrees C. Viable cells were counted at 0, 4, 8 and 24 hours. MIC: NaOCl and CHX: 0.2%, EDTA below 5%. Diffusion in agar: NaOCl 2.5% = 21 mm. CHX 0.2% = 14 mm. EDTA 17% = 20 mm. Effect on root dentin: NaOCl 2.5%: Enterococcus faecalis was totally inhibited for 24 hours in the apical area, and for 8 hours in the middle area. CHX 0.2% elicited a reduction of more than 5 log CFU and EDTA 17% induced a reduction of more than 3 log CFU at all the time points examined in the apical and middle areas.

  13. [Susceptibility of Streptococcus pyogenes to macrolides and quinolones in Guadalajara, Spain].

    PubMed

    Rodríguez-Zurita, M E; Solís del Baño, S; Robres Guillén, P; González Praetorius, A; Gimeno Fernández, C; Pérez Pomata, M T; Bisquert Santiago, J

    2003-03-01

    We carried out a retrospective study of the susceptibility of 104 Streptococcus pyogenes strains, which were isolated in 2000 and 2001 from clinical samples of different origins, to penicillin, erythromycin, clindamycin, ofloxacin and levofloxacin. The susceptibility testing was performed using the agar difusion method according to the guidelines of the NCCLS. All of the isolates showed susceptibility to penicillin and clindamycin. However, we detected 11 strains that were resistant to erythromycin (10.6%) and 4 strains resistant to ofloxacin (3.8%). We studied the resistance phenotypes of macrolides and lincosamides using erythromycin and clindamycin discs. Nine of the eleven strains that were resistant to erythromycin showed an M phenotype, while the remaining two showed inducible resistance to clindamycin, thus suggesting an MLS(B) inducible phenotype. No strains with constitutive resistance to erythromycin or clindamycin (MLS(B) constitutive phenotype) were identified. While penicillin is still uniformly active against S. pyogenes, in Guadalajara, there are 10.6% strains that are resistant to 14- and 15-atoms macrolides.

  14. [Clinico-histologic-morphometric correlations in pulmonary arteries among patients with heart malformations ].

    PubMed

    Fischbach, H; Hoffmeister, H M; Hoffmeister, H E; Apitz, J; Schmidt, C

    1982-01-01

    To improve the evaluation of grades of pulmonary vascular lesions in congenital heart malformations, we studied the extent to which there is a measurable relationship between pressure conditions in the pulmonary circulation and the area of the media in small and medium-sized pulmonary arteries, and the possibility of a correlation between the subjective evaluation of grades of hypertensive pulmonary vascular lesions according to Heath and Edwards (1958). Material and methods. The lungs in 68 children (mean age, 22.7 months) with congenital malformations of the heart or great vessels resulting in pulmonary hypertension were examined. The lungs were fixed in a 4% formalin solution passed via the trachea under a constant filling pressure of 150 cm H2O. Peripheral as well as central tissue was removed from all lobes of the lungs; the specimens were stained with Elastica-van Gieson. The extent of hypertensive pulmonary vasculopathy was staged, without knowledge of the pressure conditions, according to the grading system developed by Heath and Edwards. The diameter and the area of all muscular arteries with diameters smaller or larger than 100 micron were measured using a semiautomatic measurement device for quantitative morphometric analysis (MOP/AM 01). Cardiac catheter values were available for all cases. The quotient of systolic pressures in the pulmonary artery and the aorta was taken as the measure of hemodynamic conditions in the pulmonary circulation. The Pearson-Bravais correlation coefficient (r) was computed from the respective area quotient and the corresponding pressure values. In addition, the coefficient of determination (r2) and regression functions were determined. Results. A linear correlation (r = 0.70) exists between the pressure quotient (Psyst. pulm. art./ Psyst. aorta) and the vessel area quotient (media area/total area). The correlation is expressed by the following functions: x = 1.89 y - 0.08 y = 0.26 x + 0.24 Using the Heath and Edwards grading

  15. Intracranial vertebral artery dissection resulting in fatal subarachnoid hemorrhage: clinical and histopathological investigations from a medicolegal perspective.

    PubMed

    Ro, Ayako; Kageyama, Norimasa; Abe, Nobuyuki; Takatsu, Akihiro; Fukunaga, Tatsushige

    2009-05-01

    Subarachnoid hemorrhage (SAH) due to a ruptured intracranial vertebral artery (VA) dissection sometimes results in a sudden fatal outcome. The authors analyzed the relationship between clinical features and histopathological characteristics among fatal cases to establish valuable information for clinical diagnostics and prophylaxis. This study included 58 medicolegal autopsy cases of ruptured intracranial VA dissection among 553 fatal nontraumatic cases of SAH that occurred between January 2000 and December 2007. Their clinical features were obtained from autopsy records. Histopathological investigations were performed on cross-sections obtained from all 4-mm segments of whole bilateral intracranial VAs and prepared with H & E and elastica van Gieson staining. The autopsy cases included 47 males and 11 females, showing a marked predilection for males. The mean age was 46.8 +/- 7.7 years, with 78% of the patients in their 40s or 50s. Hypertension was the most frequently encountered history; it was found in 36% of cases from clinical history and in 55% of cases based on autopsy findings. Prodromal symptoms related to intracranial VA dissections were detected in 43% of patients. Headache or neck pain lasting hours to weeks was a frequent complaint. Of patients with prodromal symptoms, 44% had consulted doctors; however, in none of these was SAH or intracranial VA dissection diagnosed at a preventable stage. Autopsy revealed fusiform aneurysms with medial dissecting hematomas. Apart from ruptured intracranial VA dissection, previous intracranial VA dissection was detected in 25 cases (43%); among them, 10 showed previous dissection of the bilateral intracranial VAs. The incidence of prodromal symptoms (60%) among the patients with previous intracranial VA dissection was significantly higher than that (30%) among cases without previous dissection (chi-square test; p = 0.023). Most previous intracranial VA dissections formed a single lumen resembling nonspecific

  16. [Impact of olmesartan medoxomil on atherosclerosis lesions in apolipoprotein E knockout mice].

    PubMed

    Li, H; Shi, L Y; Chen, L; Lu, Y Z; Yu, B; Qi, G X

    2016-08-16

    To investigate the effect and possible mechanisms of olmesartan medoxomil on atherosclerosis of apolipoprotein E knockout (ApoE(-/-)) mice. Sixteen 6-week-old male ApoE(-/-) mice were randomly divided into atherosclerosis model group fed with high fat diet, and olmesartan medoxomil intervention group fed with high fat diet and olmesartan medoxomil (10 mg·kg(-1)·day(-1,) per gavage). Eight C57BL/6 mice were fed with normal diet, and treated for 12 weeks.The blood pressure and the serum level of lipid were detected; the aorta were removed, oil red staining for plaque area, Hematoxylin and eosin (HE) staining for plaque morphology, Elastica van Gieson (EVG) staining for elastin, and picrosirius red (PSR) for collagen respectively; and the expression of cathepsin S (Cat S), smooth action protein (ASMA) and macrophage surface molecule-3 (Mac-3) were detected by immunohistochemisty analysis. Serum cholesterol and low density lipoprotein levels were significantly higher in atherosclerosis model group than in control group[(15.08±1.64) vs (2.06±0.15) mmol/L, (15.60±1.05) vs (0.00±0.00) mmol/L] (all P<0.01), while triglyceride level was similar between the two group.In contrast to model group, the mice in intervention group showed no statistical difference in blood pressure and plasma lipid levels, while the plaque areas in the aorta were significantly decreased (P<0.05) as well as the expression of Cat S and Mac-3[(2.4±1.2) vs (8.8±3.2)%, (2.2±1.2) vs (7.2±2.8)%] (all P<0.01). In addition, the elastin levels, collagen contents, and the expression of ASMA remained significantly higher compared with model group (P<0.05). Olmesartan medoxomil could slow down the atherosclerosis process, the possible mechanism was implicated with the suppression of Cat S and decreased inflammatory responses alongside the increased elastin and collagen contents.

  17. Polymer-induced forces at interfaces

    NASA Astrophysics Data System (ADS)

    Rangarajan, Murali

    This dissertation concerns studies of forces generated by confined and physisorbed flexible polymers using lattice mean-field theories, and those generated by confined and clamped semiflexible polymers modeled as slender elastic rods. Lattice mean-field theories have been used in understanding and predicting the behavior of polymeric interfacial systems. In order to efficiently tailor such systems for various applications of interest, one has to understand the forces generated in the interface due to the polymer molecules. The present work examines the abilities and limitations of lattice mean-field theories in predicting the structure of physisorbed polymer layers and the resultant forces. Within the lattice mean-field theory, a definition of normal force of compression as the negative derivative of the partition-function-based excess free energy with surface separation gives misleading results because the theory does not explicitly account for the normal stresses involved in the system. Correct expressions for normal and tangential forces are obtained from a continuum-mechanics-based formulation. Preliminary comparisons with lattice Monte Carlo simulations show that mean-field theories fail to predict significant attractive forces when the surfaces are undersaturated, as one would expect. The corrections to the excluded volume (non-reversal chains) and the mean-field (anisotropic field) approximations improve the predictions of layer structure, but not the forces. Bending of semiflexible polymer chains (elastic rods) is considered for two boundary conditions---where the chain is hinged on both ends and where the chain is clamped on one end and hinged on the other. For the former case, the compressive forces and chain shapes obtained are consistent with the inflexional elastica published by Love. For the latter, multiple and higher-order solutions are observed for the hinged-end position for a given force. Preliminary studies are conducted on actin-based motility

  18. A fibril-based structural constitutive theory reveals the dominant role of network characteristics on the mechanical behavior of fibroblast-compacted collagen gels.

    PubMed

    Feng, Zhonggang; Ishiguro, Yuki; Fujita, Kyohei; Kosawada, Tadashi; Nakamura, Takao; Sato, Daisuke; Kitajima, Tatsuo; Umezu, Mitsuo

    2015-10-01

    elasticas with linear elasticity within the gels, and that the macroscale nonlinearity of the gels originates from the curved fibrillar network. Meanwhile, the underlying factors that determine the mechanical properties of the gels are clarified. Finally, the implications of this study on the enhancement of the mechanical properties of compacted collagen gels and on the cellular mechanics with this model tissue are discussed.

  19. Compressive response and failure of braided textile composites: Experiments and analysis

    NASA Astrophysics Data System (ADS)

    Quek, Shu Ching

    Textile composites have similar mechanical attributes when compared with other fiber reinforced composites, however, because of cost effective manufacturability, they are being considered as a viable alternative for structural applications in the aerospace and automotive industries. This thesis focuses on the compressive response of a 2D flat triaxial braided composite (2DTBC) under conditions that are similar to those encountered when a tubular structural member undergoes axial compressive crush. During crush, the walls of the member are subjected to predominantly biaxial stress state of compression (lengthwise) and tension (widthwise), while, near the end of the tube where the loading is introduced, a combined bending and compression type of biaxial stress state is predominant. Experiments on flat 2DTBCs were carried out under two types of load states: compression/tension (C/T) and bending/compression (B/C). C/T tests were carried out on a special planar biaxial load frame. External loads and full field planar incremental strain fields (the Deltaepsilonx, Deltaepsilon y and Deltagammaxy) were captured during the loading process via digital speckle photography (DSP). Failure mechanisms were investigated and supplemented by post experiment microscopy. Similarly, load and strain data were obtained from the B/C tests, which was based on a novel eccentric Elastica experimental configuration. The experimental results provided fundamental insight into the failure mechanisms of 2DTBCs and motivated the development of robust micromechanics based strength models for the 2DTBCs. In addition, the biaxial experimental data provide grounds for the validation of failure theories that have been conceived on measurements based on uniaxial loading. An analytical model based on constituent properties and textile geometry as input was developed to determine the elastic orthotropic stiffness properties of a 2DTBC. A finite element (FE) based micromechanics model of the 2DTBC was

  20. Estudo em microondas do aprisionamento e precipitação de elétrons em explosões solares

    NASA Astrophysics Data System (ADS)

    Rosal, A. C.; Costa, J. E. R.

    2003-08-01

    emissão e a relação dos índices espectrais, dpés > dtopo prioriza as interpretações com difusão em ângulo de passo devida a colisões Coulombianas. Nesta difusão o déficit de elétrons energéticos na precipitação seria uma conseqüência natural da dependência em e-3/2 das colisões elétron-próton (onde e é a energia dos elétrons).

  1. [Cushing syndrome due to ectopic ACTH secretion].

    PubMed

    Mendonça, B B; Madureira, G; Bloise, W; Albergaria, A; Halpern, A; Liberman, B; Villares, S M; Batista, M C; Avancini, V F; Nitterdorfi, C T

    1989-01-01

    The authors studied 8 patients (4 males and 4 females) with Cushing's syndrome due to ectopic ACTH secretion. Chronological age ranged from 15 to 45 years and duration of the disease ranged from 3 to 48 months. All patients presented typical signs of Cushing's syndrome, blood hypertension, and four of them had hyperpigmentation of the skin. Five patients had fasting hyperglycemia and all patients but one had serum hypokalemia (serum K = 2.2 to 3.9mEq/l). The circadian rhythm of cortisol was absent in all patients and basal cortisol levels were elevated in all patients but one. Basal ACTH levels evaluated in 7 patients were elevated in 6 (29 to 1050 pg/ml-MRC). One patient presented normal depression of urinary 17-OH after two days of dexamethasone and normal increase of urinary 17-OH and serum 11-dexycortisol after methyrapone. Four patients had carcinoid tumor (3 thymic and 1 bronchial), two had pancreatic islets cell tumors, one had bilateral pheochromocytoma and medular carcinoma of the thyroid, and one had oat cell carcinoma of the lung and medular carcinoma of the thyroid. Thoracic X-rays identified the ectopic ACTH secretion tumor in four cases, all confirmed by CT scan. Abdominal CT showed a difuse enlargement of the adrenals in seven cases and bilateral nodules in one case (pheochromocytomas). Six patients died within 3 years of the diagnosis. The authors concluded that clinical and hormonal findings could mislead the findings of ACTH ectopic secretion and Cushing's disease, and suggest that thoracic X-rays and CT scans of the skull, thorax, and abdome should be done in all cases of Cushing's syndrome.

  2. [Biopersistence and systemic distribution of intramuscularly injected particles: what impact on long-term tolerability of alum adjuvants?].

    PubMed

    Gherardi, Romain K; Cadusseau, Josette; Authier, François-jérôme

    2014-01-01

    Aluminium oxyhydroxide (alum), a nanocrystalline compound that forms agglomerates, has been widely used as a vaccine adjuvant since 1927, but the mechanisms by which it stimulates immune responses remain poorly understood. Although generally well tolerated, alum may occasionally cause chronic health problems in presumably susceptible individuals. Some individuals may rarely develop delayed-onset diffuse myalgia, chronic exhaustion and cognitive dysfunction, associated with long-term persistence (up to 12 years) of alum-loaded macrophages at site of i.m. immunization, defining so-called macrophagic myofasciitis (MMF). Symptoms are consistent with the chronic fatigue/myalgic encephalomyelitis (CFS/ME) syndrome, and have been used as a paradigm of the "autoimmune/inflammatory syndrome induced by adjuvants" (ASIA). Cognitive dysfunction is reminiscent of that described in workers exposed to inhaled Al particles. Individual susceptibility may influence both alum biopersistence and difusion away from injection sites. Biopersistent particles such as fluorescent alum-coated nanohybrids, when injected into mouse muscle, are captured by monocyte-lineage cells and then carried to distant organs, draining lymph nodes and blood, probably via the thoracic duct, with delayed and accumulative translocation to the brain (microglial cells). Brain penetration occurs at extremely low levels in normal conditions, possibly explaining the good tolerance of alum despite its high neurotoxic potential. However, systemic diffusion is considerably enhanced by the potentiating effect of MCP-1, the main monocyte chemoattractant factor, the production of which is subject to marked variations linked to age and to genetic and environmental factors. Selective MCP-1 elevation is the only known circulating biomarker of MMF.

  3. The preparation and evaluation of sustained release suppositories containing ketoprofen and Eudragit RL 100 by using factorial design.

    PubMed

    Ozgüney, I; Ozcan, I; Ertan, G; Güneri, T

    2007-01-01

    The preparation of ketoprofen (KP) sustained release (SR) suppositories was designed according to the 3(2) x 2(1) factorial design as three different KP:Eudragit RL 100 ratios (1:0.5, 1:1, 1:2), three particle sizes of prepared granules (250-500, 500-710, and 710-1000 microm) and two different PEG 400:PEG 6000 ratios (40:60, 50:50). The conventional KP suppositories were also prepared by using Witepsol H 15, Massa Estarinum B, Cremao and the mixture of PEG 400:PEG 6000. The dissolution studies of suppositories prepared were carried out according to the USP XXIII basket method in the phosphate buffer (pH = 7.2) at 50 rpm, and it was shown that the dissolution time was sustained up to 8 hours. According to the results of the factorial design, the most important independent variable on t50 and t80 was drug:polymer ratios. The log of partition coefficient of KP was determined as 1.46, showing the high affinity to the oily phase. n exponent and kinetic studies were conducted to explain diffusion mechanism, and it is understood that if the inert KP:Eudragit RL 100 ratio is increased in the particles, the Fickian difusion dominates and the best kinetic turns to Higuchi from the Hixson-Crowell. There is neither crystalline form of KP nor degradation product in the suppositories detected with the differential scanning calorimetry (DSC) studies. In addition to these studies, antiinflammatory activity of SR suppositories also determined that it was significantly extended according to the conventional suppositories.

  4. Endogenous superoxide dismutase activation by oral administration of riboflavin reduces abdominal aortic aneurysm formation in rats.

    PubMed

    Yu, Zhenhai; Morimoto, Keisuke; Yu, Jie; Bao, Wulan; Okita, Yutaka; Okada, Kenji

    2016-09-01

    Vitamin B2 (riboflavin) reportedly has an antioxidant effect through superoxide dismutase (SOD) activation. However, the effect of riboflavin on abdominal aortic aneurysm (AAA) has never been investigated. In the present study, we examined the hypothesis that riboflavin has a protective effect on AAA formation in an experimental rat model. The AAA model, which was induced with intraluminal elastase and extraluminal calcium chloride, was created in 36 rats. The 36 rats were divided into a riboflavin group (group R; 25 mg/kg/d), and control group (carboxymethyl cellulose). Riboflavin administration by gastric gavage once per day was started at 3 days before aneurysm preparation. On day 3, SOD activity in aneurysm walls was assayed. On day 7, reactive oxygen species (ROS) levels were semiquantified by dihydroethidium staining, and the oxidation product of DNA produced by ROS, 8-hydroxydeoxyguanosine (8-OHdG), was measured by immunohistochemical staining. Histopathologic examination (hematoxylin/eosin and elastica Van Gieson staining) was performed on day 28, and the AAA dilatation ratio was calculated to evaluate the protective effect of riboflavin. On day 3, SOD activity was significantly increased in aneurysm walls by riboflavin administration (370 ± 204 U/mL in normal, 334 ± 86 U/mL in control, 546 ± 143 U/mL in group R; P = .021). On day 7, ROS levels and 8-OHdG-positive cells in aneurysm walls were significantly decreased by riboflavin treatment (ROS levels: 1.0 ± 0.1 in normal, 4.5 ± 0.4 in control, 3.1 ± 0.5 in group R, P < .01; 8-OHdG-positive cells: 30 ± 2 cells in normal, 148 ± 20 cells in control, 109 ± 15 cells in group R, P < .01). Riboflavin treatment significantly reduced matrix metalloproteinase (MMP)-9 messenger RNA expression in aneurysm walls (relative expression: MMP-9: 0.4 ± 0.7 in normal, 2.6 ± 1.3 in control, 0.5 ± 0.3 in group R, P < .01). On day 28, the aortic walls were less dilated and had higher elastin content

  5. Vertebral column and associated elements in dipnoans and comparison with other fishes: development and homology.

    PubMed

    Arratia, G; Schultze, H P; Casciotta, J

    2001-11-01

    A vertebral column consisting of a persistent notochord and ossified arcocentra is the primitive condition for Gnathostomata; it still persists in primitive actinopterygians and sarcopterygians. Advanced actinopterygians and sarcopterygians develop numerous types of centra that include, among others, the presence of holocentrum, chordacentrum, and autocentrum. The chordacentrum, a mineralization or calcification of the fibrous sheath of the notochord, is only found in actinopterygians, whereas an autocentrum is a synapomorphy of teleosts above Leptolepis coryphaenoides. The chordacentrum, formed by migration of cartilaginous cells from the arches into the fibrous sheath of the notochord and usually covered by a thin calcification, is a unique feature of chondrichthyans. The actinopterygian chordacentrum and the chondrichthyan chordacentrum are not homologous. The postcaudal cartilaginous centrum is only known in postcaudal vertebrae of living dipnoans. The holocentrum is present in certain fossil dipnoans and actinopterygians, where it has been independently acquired. It is formed by proliferation of cartilage cells around the elastica externa of the notochord. These cells later ossify, forming a compact centrum. A vertebral column formed by a persistent notochord without vertebral centra is the primitive pattern for all vertebrates. The formation of centra, which is not homologous among vertebrate groups, is acquired independently in some lineages of placoderms, most advanced actinopterygians, and some dipnoans and rhipidistians. Several series of structures are associated with the vertebral column such as the supraneurals, interhaemals, radials, and ribs. In living dipnoans median neural spine, "supraneural," and dorsal radial result from growth and distal differentiation of one median cartilage into two or three median bones during ontogeny. The median neural spine articulates with the neural arch and fuses with it in the caudal vertebrae early in ontogeny. Two

  6. Usina de ciências: um espaço pedagógico para aprendizagens múltiplas

    NASA Astrophysics Data System (ADS)

    Martin, V. A. F.; Poppe, P. C. R.; Orrico, A. C. P.; Pereira, M. G.

    2003-08-01

    Entendemos que o Ensino de Astronomia é especialmente apropriado para motivar os alunos e aprofundar conteúdos em diversas áreas do conhecimento, pois envolve temas ligados à Física, Matemática, Química, Computação, Tratamento de Imagens e Instrumentação de Alta Precisão, além daqueles pertinentes as áreas de Geografia, História e Antropologia. Contudo, apesar do caráter interdisciplinar que esta ciência possui, a realidade atual é que a maioria dos professores em sala de aula não foram devidamente capacitados, durante o período de formação acadêmica, para ministrar conteúdos de Astronomia nos atuais Ensinos Fundamental e Médio. Neste trabalho, discutiremos de maneira ampla, num primeiro momento, a realidade do atual ensino de ciências praticado no Estado da Bahia, apontando por dependência administrativa, o crescimento e a redução do número de escolas, da taxa de analfabetismo por faixa etária, da escolarização, do atendimento, da aprovação, reprovação e abandono, de equipamentos e laboratórios e o grau de formação dos nossos atuais professores em pleno exercício de atividade docente. Num segundo momento, discutiremos o papel do Observatório Astronômico Antares/UEFS dentro desse contexto, ou seja, suas ações implementadas ao longo dos últimos anos e em particular, o recente projeto de extensão Ensino e Difusão de Astronomia, financiado pela Fundação Vitae, que procura traduzir no lúdico, no brincar de ciências, um espaço pedagógico para aprendizagens múltiplas. Neste, o papel do professor multiplicador associado ao laboratório de kits didáticos, de fácil construção e manipulação (alguns dos quais serão mostrados), perfazem os principais veículos para o desenvolvimento de conhecimentos, atitudes, habilidades e valores que preparam os nossos alunos para a carreira técnico-científica e para sua participação crítica e criativa na Sociedade.

  7. Booklets for children related with Earth Sciences published in Mexico

    NASA Astrophysics Data System (ADS)

    Alaniz, S. A.; Nieto-Samaniego, A. F.

    2009-04-01

    The Centro de Geociencias, at the Universidad Nacional Autonoma de Mexico, has published a series of booklets for children, entitled "Simple experiments to understand a complex Earth". It is part of the activities of the Mexican committee of the International Year of the Planet Earth. Each booklet contains experiments related with an Earth Sciences topic and includes the procedure to do one of the "Ten most beautiful experiments in physics" (Crease, P., Physics World May 2002 p17 and September 2002 pp19-20). In Mexico, as in other developing countries, there is very little information about Science in general and Earth Sciences in particular, in the basic education programs. Also, there is poor bibliography in Spanish about science experiments. For this reason, we try to fill the vacuum by distributing free the booklets in Science Museums and rural basic schools in paper, and by Internet in the Centro de Geociencias web site (http://www.geociencias.unam.mx/geociencias/difusion/indice.html). At present, we have been distributed 100,000 copies of 5 issues: 1."Atmospheric pressure and the falling bodies", it deals with the Galileo experiment of falling bodies, he proposed that all the bodies fall down at the same velocity. We discuss the properties of the atmosphere air (temperature, pressure and volume) and concluded that Galileo is right but when the bodies are very light. 2. "The light and the colors" is based in the Newton's decomposition of sunlight with a prism experiment. This booklet contains nine experiments to explain the colors that we find in Earth like the blue of the sky, the orange of the sunset, the rainbow and the mirage. 3. "¿Eureka! oceans and continents float". This booklet presents seven experiments related with density and buoyancy to explain the principles of the Plate tectonics theory. 4. "Climate hanging by a thread", Foucault pendulum demonstrates the rotation of Earth without seeing the stars, in this booklet, we explain, through 9

  8. Studies of water diffusion in the vicinity of single-supported lipid membranes

    NASA Astrophysics Data System (ADS)

    Miskowiec, Andrew

    The insertion and function of membrane-embedded proteins is one of the most fundamental challenges facing biological physics today. At its core, addressing these phenomena requires an understanding of the interaction of proteins with the lipid bilayer and its associated water molecules. As such, the study of water dynamics and structure near model lipid bilayers can provide foundational knowledge upon which more detailed understanding of these core issues may be developed. Previous quasielastic neutron scattering measurements on lipid membranes have used samples of large stacks of membranes with an unknown amount of water between layers. This geometry complicates interpretation and renders comparison to molecular dynamics simulations difficult. Instead, this work investigates water dynamics on single-supported bilayers of the model charge-neutral lipid DMPC (dimyristoyl-sn- glycero-3-phosphocholine) and its anionic analogue DMPG (dimyristoyl-sn-glycero- 3-phosphoglycerol). Single bilayers can be more directly compared to molecular dynamics simulations, can be interrogated with Atomic Force Microscopy, and avoid the uncertainty in quantifying the amount of water in samples. A new method for producing the anionic bilayers is developed, which is a variant of the vesicle fusion method. Atomic Force Microscopy is used to characterize the quality of both DMPC and DMPG membranes supported on SiO2-coated silicon substrates. Measuring the bilayer thickness as a function of temperature reveals that the gel-to-fluid phase transition is found to be shifted to significantly higher temperatures for adsorbed lipid bilayers in air compared to free vesicles in solution. The temperature-dependent quasielastic spectra from hydrated DMPC bilayers reveal three types of membrane-associated water. First, a large amount of water difuses similarly to bulk supercooled water and freezes at 265 K. Second, a smaller amount of water closer to the membrane diffuses more slowly than bulk

  9. [Role of cytokine-matrix metalloproteinase axis on promoting vascular neointima hyperplasia in mice].

    PubMed

    Liu, Y; Ning, W H; Shen, X H; Guo, D L; Guo, L

    2016-11-24

    Objective: To observe the effects of tumor necrosis factor-α (TNF-α) and platelet derived growth factor (PDGF) on vascular neointimal hyperplasia on matrix metalloproteinase 9/2 gene knockout (MMP9/2(-/-)) mice and explore related mechanisms. Methods: Mice of control group, MMP9(-/-) group, MMP2(-/-) group and MMP9/2(-/-) group were studied. Femoral artery was injured by transluminal wire, the mRNA expression levels of TNF-α and PDGF on femoral artery were detected by RT-PCR; the protein expression of MMP9 and MMP2 were assessed by Western blot on day 0, 1, 3, 7, 14 and 28 post injury. Mice in control group received TNF-α(5 ng/ml, 0.10 ml), TNF-α(0.05 ml)+ MMP inhibitor SB-3CT(0.50 ng/ml, 0.05 ml) injection, or PDGF-bb (10 ng/ml, 0.10 ml)and PDGF-bb(0.05 ml)+ SB-3CT(0.05 ml)injection around injured artery, intimal hyperplasia at 2 and 4 weeks after injury was observed. Intimal hyperplasia at 2 and 4 weeks after injury was also observed in MMP9/2(-/-) mice. TNF-α(5 ng/ml, 0.10 ml)was injected to MMP2(-/-) mice, PDGF-bb (0.1 ml) was injected to MMP9(-/-) mice around injured artery, intimal hyperplasia at 2 and 4 weeks after injury was observed. The degree of neointimal hyperplasia were observed by the Elastica-van Gieson staining and the area of neointima and media of the arteries were measured by SigmaPlot and intima ratio was calculated. Vascular smooth muscle cell (VSMC) mediums of MMP9(-/-) and MMP2(-/-) mice were stimulated by TNF-α and PDGF-bb, respectively, and migration assay, and proliferation assay were performed, relative migration and proliferation cells numbers were counted. Results: (1) mRNA expression of TNF-α (235.33±23.68) and PDGF-bb (3.30±0.56) in femoral arteries peaked at 1 day after injury, while MMP9 or MMP2 protein expression peaked at 7 or 28 days after injury. (2)In control mice, TNF-α intervention significantly enhanced intimal hyperplasia at 2 weeks after injury (2.21±0.05 vs. 1.55±0.03 in blank control group, P<0.05), while

  10. Earth meandering

    NASA Astrophysics Data System (ADS)

    Asadiyan, H.; Zamani, A.

    2009-04-01

    In this paper we try to put away current Global Tectonic Model to look the tectonic evolution of the earth from new point of view. Our new dynamic model is based on study of river meandering (RM) which infer new concept as Earth meandering(EM). In a universal gravitational field if we consider a clockwise spiral galaxy model rotate above Ninety East Ridge (geotectonic axis GA), this system with applying torsion field (likes geomagnetic field) in side direction from Rocky Mt. (west geotectonic pole WGP) to Tibetan plateau TP (east geotectonic pole EGP),it seems that pulled mass from WGP and pushed it in EGP due to it's rolling dynamics. According to this idea we see in topographic map that North America and Green land like a tongue pulled from Pacific mouth toward TP. Actually this system rolled or meander the earth over itself fractaly from small scale to big scale and what we see in the river meandering and Earth meandering are two faces of one coin. River transport water and sediments from high elevation to lower elevation and also in EM, mass transport from high altitude-Rocky Mt. to lower altitude Himalaya Mt. along 'S' shape geodetic line-optimum path which connect points from high altitude to lower altitude as kind of Euler Elastica(EE). These curves are responsible for mass spreading (source) and mass concentration (sink). In this regard, tiltness of earth spin axis plays an important role, 'S' are part of sigmoidal shape which formed due to intersection of Earth rolling with the Earth glob and actual feature of transform fault and river meandering. Longitudinal profile in mature rivers as a part of 'S' curve also is a kind of EE. 'S' which bound the whole earth is named S-1(S order 1) and cube corresponding to this which represent Earth fracturing in global scale named C-1(cube order 1 or side vergence cube SVC), C-1 is a biggest cycle of spiral polygon, so it is not completely closed and it has separation about diameter of C-7. Inside SVC we introduce cone

  11. [Neuroimaging and Blood Biomarkers in Functional Prognosis after Stroke].

    PubMed

    Branco, João Paulo; Costa, Joana Santos; Sargento-Freitas, João; Oliveira, Sandra; Mendes, Bruno; Laíns, Jorge; Pinheiro, João

    2016-11-01

    Introdução: O acidente vascular cerebral é uma das principais causas de mortalidade e morbilidade em todo o mundo, associando-se a considerável incapacidade funcional. Atualmente sabe-se que tanto técnicas de neuroimagem como determinados biomarcadores fornecem informações úteis acerca da etiologia, decisão terapêutica, follow-up e prognóstico em doentes com acidente vascular cerebral isquémico. Assiste-se, porém, a um interesse particular na previsão do prognóstico vital em detrimento do prognóstico funcional. Antecipar o prognóstico funcional permitiria definir um programa de reabilitação adequado, objetivo e individualizado, com uma alocação de recursos mais eficiente. O presente trabalho tem como objetivo rever o conhecimento atual acerca do papel da neuroimagem e dos biomarcadores sanguíneos em fase aguda na previsão da recuperação funcional dos doentes que sobrevivem a um acidente vascular cerebral isquémico. Material e Métodos: Revisão da literatura publicada entre 2005 e 2015, em língua inglesa, utilizando os termos “ischemic stroke”, “neuroimaging” e “blood biomarkers”. Resultados: Foram selecionados nove artigos com base na leitura dos resumos. Discussão: Técnicas de neuroimagem como a tomografia computorizada, a ecografia doppler transcraniana, a angiografia cerebrale a imagem de difusão por ressonância magnética apresentam potencial preditivo do prognóstico funcional do acidente vascular cerebral, nomeadamente através da avaliação do fluxo sanguíneo e do volume e localização da lesão, sobretudo quando usados em associação com a National Institutes of Health Stroke Scale. Vários biomarcadores têm sido estudados como potenciais marcadores de diagnóstico, estratificação de risco e previsão de prognóstico no acidente vascular cerebral, em particular a S100 calcium binding protein B, a proteína C-reativa, as metaloproteinases de matriz e o peptídeo natriurético cerebral. Conclus

  12. Um Projeto de Intervenção nos Espaços de Exposições do Planetário do Parque do Ibirapuera

    NASA Astrophysics Data System (ADS)

    Elias, D. S.; Amaral, L. H.; de Araújo, C. F., Jr.; Matsuura, O. T.; Voelzke, M. R.

    2005-08-01

    Cada vez mais a humanidade, em sua imensa maioria, está alheia às próprias conquistas. A insatisfação com esta realidade tem levado muitos pesquisadores, instituições, empresas e governos a procurar formas alternativas de acompanhar e transmitir todo este acervo científico cultural à sociedade, buscando a melhoria da qualidade da divulgação científica e contribuindo para o processo de cultura e alfabetização científica. Não há tempo nem espaço nos limitados planos curriculares do ensino médio e mesmo nos programas de ensino que propiciem a cultura científica e o acompanhamento do vertiginoso progresso científico e tecnológico atual. Neste sentido, a educação formal escolar precisa ser complementada ou acrescida de uma educação informal, extra-escolar, que possa oferecer à sociedade o que a escola não pode oferecer. A interação do público com museus, feiras de ciências, planetários, exposições científicas e/ou culturais é de grande importância para a aquisição e difusão de conhecimentos relacionados ao mundo científico. Reconhecidamente como um modelo de alfabetização científica esses ambientes promovem uma interação social capaz de propiciar de forma efetiva uma melhor relação ensino-aprendizagem com o público. Partindo desta realidade a Universidade Cruzeiro do Sul e a Escola Municipal de Astronomia (EMA) vêm desenvolvendo um projeto de intervenção no espaço em torno do Planetário do Parque do Ibirapuera com o objetivo de se implantar um ambiente de aprendizagem motivador e desafiador que promova a popularização de conteúdos relacionados à astronomia, astrofísica e cosmologia. Busca-se, também, a aproximação e interação do público com exposições que estão sendo implementadas no planetário. Considerando que se trata de um projeto de mestrado em fase inicial o objetivo do presente trabalho é apresentar a concepção básica e os critérios que estão sendo utilizados do ponto de vista pedag

  13. The impact of the use of different types of gloves and bare hands for preparation of clean surgical instruments.

    PubMed

    Bruna, Camila Quartim de Moraes; Souza, Rafael Queiroz de; Massaia, Irineu Francisco Silva; Cruz, Áurea Silveira; Graziano, Kazuko Uchikawa

    2016-10-10

    to determine if there are differences on the safety of the preparation of clean surgical instruments using different types of gloves and bare hands and evaluate the microbiological load of these preparations without gloves. laboratory procedure with a pragmatic approach, in which the samples were handled with different types of gloves and bare hands. In addition, cytotoxicity assays were carried out by means of the agar diffusion method. Further samples were subjected to microbiological analysis after being handled without gloves. none of the samples showed cytotoxic effect. All microbiological cultures showed growth of microorganisms, but no microorganism has been recovered after autoclaving. there were no differences in the cytotoxic responses regarding the use of different types of gloves and bare hands in the handling of clean surgical instruments, which could entail iatrogenic risk. It is noteworthy that the use of gloves involves increase in the costs of process and waste generation, and the potential allergenic risk to latex. determinar se existe diferenças na segurança do preparo de instrumentais cirúrgicos relacionada ao uso de distintos tipos de luvas e das mãos nuas no preparo, e avaliar a carga microbiológica destes preparados sem luvas. experimento laboratorial com abordagem pragmática, onde amostras foram manipuladas com diferentes tipos de luvas e com as mãos nuas, elaborado teste de citotoxicidade por meio da difusão em ágar. Outras Amostras sofreram análise microbiológica após serem manipuladas sem luvas. nenhuma das amostras apresentou efeito citotóxico. Todas as culturas microbiológicas apresentaram crescimento de microrganismos, embora nenhum microrganismo tenha sido recuperado após a autoclavação. não houve diferenças nas respostas citotóxicas relacionadas ao uso de diferentes tipos de luvas e das mãos nuas na manipulação do instrumental cirúrgico limpo que sinalizasse risco de iatrogenia. Ressalta-se que o uso de luvas

  14. [Magnetic Resonance Imaging Conversion Predictors of Clinically Isolated Syndrome to Multiple Sclerosis].

    PubMed

    Peixoto, Sara; Abreu, Pedro

    2016-11-01

    Introdução: A síndrome clinicamente isolada é uma forma de apresentação da esclerose múltipla, doença desmielinizante crónica do sistema nervoso central, e define-se por um único episódio clínico sugestivo de desmielinização. Porém, doentes com esta síndrome podem não desenvolver novos sintomas ou lesões, mesmo após longos períodos de seguimento, não cumprindo os critérios de diagnóstico da doença. Aqui serão revistas, na síndrome clinicamente isolada, as alterações na ressonância magnética que melhor predizem a conversão em esclerose múltipla. Material e Métodos: Pesquisaram-se na base de dados da PubMed artigos publicados entre janeiro de 2010 e junho de 2015 usando os termos ‘clinically isolated syndrome’, ‘cis’, ‘multiple sclerosis’, ‘magnetic resonance imaging’, ‘magnetic resonance’ e ‘mri’. Resultados: Carga lesional, localização das lesões, critérios de Barkhof e áreas/volumes de estruturas cerebrais foram as alterações na ressonância magnética convencional encontradas nos artigos incluídos nesta revisão. As técnicas não convencionais estudadas foram a dupla inversão-recuperação, a transferência de magnetização, a espectroscopia e a imagem de tensor de difusão. Discussão: Enquanto o número de lesões e a sua localização têm um papel claro na previsão da conversão da síndrome clinicamente isolada em esclerose múltipla, as técnicas não convencionais e as restantes alterações na ressonância magnética necessitam de mais estudos para confirmar a sua capacidade de prever o desenvolvimento da doença. Conclusão: Para além do valor preditivo das alterações já citadas, no futuro, diferentes achados neurorradiológicos na síndrome clinicamente isolada poderão ser considerados para os critérios de diagnóstico da esclerose múltipla e/ou modificar as recomendações sobre o seu tratamento.

  15. Distribution of heavy metals in riverine soils and sediments of the Turia River basin.

    NASA Astrophysics Data System (ADS)

    Andreu, Vicente; Gimeno-García, Eugenia; Pascual, Juan Antonio

    2014-05-01

    Water is a scarce and contested good, and a primary need for the population all over. Rivers are one of the mainsources of freshwater to people but, in the same way, receive both point source and difuse pollution, usually frorm wastewaters and agriculture. However, they are not independent bodies but they influence different associated ecosystems that compound the catchment. Soils of the river banks often acts as the last phase of the diffuse contamination pathways, favouring the contaminants input to the river waters. In this sense, the fluvial sedimentary phase usually acts as a sink of pollutants. Sediments can work as resevoirs that accumulate contaminants fixing them or allowing their decomposition or metabolization. However, environmental or human induced, such as variations in water pH, increases in the turbulence or intensity of the water flow, etc.could favour their release to the environment. In this work, the incidence and distribution of seven heavy metals was monitored in riverine soils and sediments of the Turia River. Along the river course, 22 zones were selected for sampling according different lithologies, land uses, size of populations and the proximity to waste waters treatment plants (WWTPs), from the headwaters to the mouth. The selected metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) were analysed to determine its total and extractable contents in the sediments. Total content of metals was extracted by microwave acid digestion and the extractable fraction by treatment with EDTA. Atomic Absorption Spectrometry, using graphite furnace when necessary, was used for the determination of all metals. Highest values for sediments were mainly observed in zones 10 and 22, close to urban areas, reaching values of 172.86 mg/kg for Pb, or 58.34 mg/kg for Cr. However, zone 2 near in the headwaters of the Alfambra River and supposedly of reference for the River authorities shows the highest values of zinc with 96.96 mg/kg. Regarding the available

  16. Status of riverine soils, waters and sediments of a Mediterranean river catchment (the Turia river, Spain) regarding heavy metals potential contamination

    NASA Astrophysics Data System (ADS)

    Andreu, Vicente; Gimeno-García, Eugenia; Pascual-Aguilar, Juan Antonio

    2015-04-01

    One important source of freshwater to population are fluvial courses, but they receive contaminants by different ways, usually frorm wastewaters and difuse pollution. The fluvial sedimentary phase can act as resevoir that accumulate contaminants fixing them or allowing their decomposition or metabolization. However, environmental changes or human induced ones, could favour their release to the environment. In this work, seven heavy metals were monitored in soils, waters and sediments of the Turia River catchment. Along the river, 22 zones were selected for sampling according different lithologies, land uses, size of populations and the proximity to waste waters treatment plants (WWTPs), from the headwaters to the mouth. The selected metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) were analysed to determine its total and extractable contents in soils, water and sediments. Total content of metals was extracted by microwave acid digestion and the extractable fraction in soils and sediments by treatment with EDTA. Atomic Absorption Spectrometry, using graphite furnace when necessary, was used for the determination of all metals. Metal values in waters are below the limits established by the EU legislation. As in waters, the sediments show highest values mainly in zones 10 and 22, close to urban areas, reaching values of 172.86 mg/kg for Pb, or 58.34 mg/kg for Cr. However, zone 2 near in the headwaters, and supposedly of reference for the River authorities, shows the highest values of zinc (96.96 mg/kg). Regarding the available/extractable fraction of the metals, the maximum values were observeg in zone 22 too, reching in the case of Pb 59.60 mg/kg. The percentage of available metal in the sediments of the studied zones vary between 15 and 40% for Cu, Pb and Zn, being the higher than 60% for Pb and Zn in zone 8 near the city of Teruel. In soils, the higest levels of total and extractable Cd, Co, Cr and Ni were determined in the zones 11 and 12, near the Benageber reservoir where

  17. A Influência da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2006-08-01

    O universo em que vivemos possui segredos jamais imaginados pelo homem, fruto da pequena proporção que ocupamos diante de um cosmos infinito. A astronomia funciona como um instrumento que sacia a sede humana em desvendar esses segredos, estudando as galáxias, quasares, pulsares além da existência de todos os elementos que preenchem o espaço cósmico, o vácuo, não mais vazio como se pensou em outros tempos. A mídia explora esse campo de forma mística e também científica. A difusão adequada e dentro dos padrões educacionais vigentes, de conceitos astronômicos, se faz necessária, devido sua presença nos conteúdos escolares, centros de ciência e na mídia, de modo geral. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros introduziu conceitos astronômicos desde a pré-escola até o Ensino Médio. Num estudo realizado com 1.032 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um questionário que abordava conheciment os básicos em astronomia, como estes foram adquiridos e qual era a infra-estrutura oferecida pela escola: para 66,2% dos entrevistados o professor já fez alguma apresentação a respeito de astronomia. O presente estudo revelou também que 44,5% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 28,1% através da televisão e 27,4% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio na forma em que os alunos obtiveram seus conhecimentos astronômicos, a mídia ainda explora e muitas vezes desperta o interesse pela astronomia com assuntos que não fazem parte de nosso cotidiano como, por exemplo, o homem na Lua, os projetos espaciais e a primeira viagem de um astronauta brasileiro no espaço. Porém, em certos casos, a mídia pode promover conhecimentos incompletos ou mesmo equivocados sobre os conceitos que envolvam

  18. Qual o Papel da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos?

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2007-08-01

    É amplamente reconhecido que as pessoas em geral têm grande fascínio e interesse pela Astronomia. Por outro lado, o conteúdo dessa área incluído no ensino formal está longe de ser abrangente e suficiente para suprir a demanda. Esse interesse permite aperfeiçoar a divulgação e o ensino não formal de Astronomia através da mídia aliando a adequação do conteúdo à expectativa das pessoas. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros tem introduzido Astronomia desde a pré-escola até o Ensino Médio. Num estudo realizado com 1180 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um formulário contendo questões que abordavam conhecimentos básicos em Astronomia, como foram adquiridos tais conhecimentos e à infra-estrutura da escola. Para 66,1% dos entrevistados o professor já fez alguma apresentação a respeito de Astronomia. O presente estudo revelou também que 54,4% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 18,4% através da televisão e 27,1% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, livros didáticos, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio no meio em que os alunos obtiveram seus conhecimentos astronômicos, a mídia busca não somente sua difusão, mas a disponibilização desse conhecimento de maneira correta, que às vezes, não é atingido, apresentando conceitos sem fundamentação e incorretos. Por outro lado, no dia-a-dia escolar, é comum encontrar professores que vêm para as aulas com concepções prévias, que podem diferir substancialmente das idéias a serem ensinadas, dificultando o aprendizado de futuros conceitos científicos. Uma avaliação criteriosa, avaliando as dificuldades dos professores em determinar o sentido correto dos conceitos e observando a metodologia que utilizam no ensino, poderá proporcionar uma melhor

  19. Evolution of the Astronomy Concepts Along Basic Education Cycle. (Breton Title: Evolução dos Conceitos de Astronomia no Decorrer da Educação Básica.) La Evolución de los Conceptos de Astronomía Durante la Educación Básica

    NASA Astrophysics Data System (ADS)

    Darroz, Luiz Marcelo; da Rosa, Cleci Werner; Becker da Rosa, Álvaro; Samudio Pèrez, Carlos Ariel

    2014-07-01

    learning of astronomy in basic education. Embora a astronomia seja considerada uma das ciências mais antigas da humanidade e ainda que a compreensão de seus conceitos tenha trazido enormes avanços para a Ciência e, consequentemente, para a sociedade, observa-se que uma parcela significativa de pessoas encontra-se à margem desses conhecimentos. De acordo com os Parâmetros Curriculares Nacionais para a Educação Básica, cabe à escola a difusão dos conceitos cientificamente corretos, entre eles os relacionados à área de astronomia. Pertinente a essa questão, apresenta-se uma pesquisa realizada com 140 estudantes do nono ano do ensino fundamental e com 120 estudantes da terceira série do ensino médio de quatro escolas da região de Passo Fundo/RS. Buscou-se averiguar, por meio de um questionário composto de questões abertas e de múltipla escolha, o conhecimento desse grupo de estudantes acerca de termos e fenômenos astronômicos básicos e, também, verificar se o índice de acertos cresce à medida que eles avançam nas diferentes e gradativas séries dos ensinos fundamental e médio. De modo geral, os resultados apresentados demonstram que o ensino de astronomia na educação básica enfrenta deficiências. Das 20 questões investigadas, em 17 os índices de acertos são semelhantes nas respostas dadas por estudantes de nível fundamental e médio, revelando que muitas concepções equivocadas permanecem ao longo da educação básica. Isso evidencia que tais temas não são - ou são pouco - abordados durante esses dois níveis de escolarização. Assim, conclui-se que a discussão dos conceitos relacionados com a astronomia deve receber maior ênfase na abordagem dos diferentes conteúdos, sendo necessária uma ação nacional em prol do seu ensino. Acredita-se que essa ação nacional deve estar apoiada em um pilar triplo de atores coletivos: comunidade científica, comunidade astronômica semiprofissional e comunidade escolar. Por fim, esse pilar seria

  20. Sediment and plankton lift off recirculations in strong synthetic turbulence (KS)

    NASA Astrophysics Data System (ADS)

    Redondo, Jose M.; Castilla, Roberto; Sekula, Emil; Furmanek, Petr

    2014-05-01

    . (1929). A search forr the law of atmosferic diffusion. Beitr. Phys. frei. Atmos. 15:24. Redondo J M (1991). The structure of density interfaces, Ph. D. Thesis, CUP, University of Cambridge. Rodríguez A, Sánchez-Arcilla A, Redondo JM, Mosso C (1999) Macroturbulence measurements with electromagnetic and ultrasonic sensors: a comparison under high-turbulent flows. Exp Fluids 27:31-42 Redondo J M (1987). Effects of ground proximity on dense gas entrainment, Journal of Hazardous Materials, 16, 381-393. Redondo J M, Sanchez M A and Cantalapiedra I R (1995). Turbulent Mechanisms in Stratified Flows, Dynamics of Atmospheres and Oceans, 23, 454-462. Mahjoub O.B., Redondo J.M. and Babiano A.(1998), Structure functions in complex flows, Applied Scientific Research, 59, 299. Mahjoub O.B., Redondo J.M. and Babiano A.,(2000) Hyerarchy flux in nonhomogeneous flows in Turbulent diffusion in the environment Eds. Redondo J.M. and Babiano A. 249-260. Redondo J.M., (1988) Difusion turbulenta por rejilla oscilante. Revista de Geofisica 44, 163-174,. Vindel, J. M., Yagüe, C., & Redondo, J. M. (2008). Structure function analysis and intermittency in the atmospheric boundary layer. Nonlinear Processes in Geophysics, 15(6), 915-929.

  1. Farmyard Manure and Fertilizer Effects on Seed Potato (Solanum tuberosum L.) Yield in Green House Production

    NASA Astrophysics Data System (ADS)

    László, M.

    2009-04-01

    radicular, deve estar exposta ao fósforo para suprir as necessidades das plantas. Ademais, há um determinado valor de concentração de fósforo, na solução do solo, acima da qual a taxa de absorção não é aumentada. Essas considerações suscitam a possibilidade de questionar se a aplicação de fósforo em sulcos seria a forma mais eficiente de usá-lo quando se pretende alcancar elevadas produções. Deve-se lembrar entretanto, que solos tropicais, ainda com baixos teores fósforo e alta capacidade de adsorção, seria necessária dose muito elevada de P, quando aplicada á lanço, em todo o terreno. Se a aplicação localizada do fósforo pode, em parte, ser explicada, a do nitrogênio e potássio não são facilmente justificadas sob o aspecto de eficiéncia de utilização. Pelo contrário, ela pode ser questionada, principalmente pelas suas caracteristicas de difusão, pelo efeito que altas concentração de amónio e cloreto podem ter sobre a pressão osmotica da solução do solo junto aos tubérculos plantados, pelo efeito negativo do cloreto sobre a absorção de fósforo e também sobre a capacidade produtiva das plantas. Portanto, existe a possibilidade de ocorrer toxidez de amónio e de cloreto ao se aplicar doses altas dos fertilizantes nos sulcos de plantios. Isto pode determinar uma menor eficiéncia no uso dos fertilizantes. Materiais e Metodos: Nos desenvolverémos os três experimentos (i.e.: 1., 2., 3.) para aumentár-se do produção e produtividade da batata (Solanum tuberosum L.) semente pré- básica no casa de vegetação com diferentes doságens do latossolo vermelho novo, do esterco de curral e do adubo fórmula 4N:14P:8K no Empresa Brasileira de Pesquisa Agropecuaria- Centro Nacional de Pesquisas de Hortaliças, da Brazília-DF no 1990. Caracteristicas agroquímicas do solo em faixa arado (dados estimados), e conteudos N, P2O5, K2O do esterco de curral e palha de arroz queimado (dados estimados): a., caracteristicas agroquímicas do solo