Sample records for fragments particles
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1

Cambios ultraestructurales del trofoblasto en los casos de hipoxia durante la preeclampsia

Castejón, Olivar; López, Ángela J; Castejón, Oliver C
2008-09-01

Resumen en español Objetivo: Examinar la ultraestructura del sincitiotrofoblasto en placentas de embarazadas complicadas con preeclampsia con especial referencia al efecto de la hipoxia sobre la estructura fina del tejido. Métodos: Diez placentas, a término, afectadas por preeclampsia, fueron tomadas inmediatamente después del parto por cesárea y de cada una de ellas tres biopsias de la superficie maternal se disecaron en sala de parto, en especímenes de 2 a 5 mm, y se fijaron por inme (mas) rsión en glutaraldehido al 4 %, pH 7,4, a 4º C. Posteriormente se dividieron en fragmentos de 1 mm y sumergidos en solución fresca fijadora por períodos variables de 2 a 72 horas seguidas por una fijación secundaria en tetraóxido de osmio al 1 % en buffer fosfato 0,1 M durante 1 hora. Las muestras se procesaron siguiendo los procedimientos convencionales de la microscopia electrónica de transmisión para su observación. Ambiente: Laboratorio de microscopia electrónica del Ciadana, Facultad de Ciencias de la Salud, Maracay. Resultados: Los hallazgos revelan proyecciones de la membrana plasmática del sincitio de diversas formas, que simulan desprenderse de la superficie. La membrana basal del sincitio se mostró engrosada. Mitocondrias en diversos grados de degeneración presentaron partículas electron densas en la matriz mitocondrial. Regiones apicales del citoplasma sincitial parecen desprenderse hacia el espacio intervelloso. Numerosas vacuolas intracitoplasmáticas y ampliaciones de las cisternas del retículo endoplásmico rugoso se destacan en el citoplasma. Interrupciones de la membrana sincitial y regiones citoplásmicas sin membrana plasmática se notaron. Conclusión: Fragmentos del sincitio desprendidos de la superficie del mismo sugieren ser los corpúsculos que dañan los endotelios de la unidad materna - feto - placentaria constituyendo uno de los estímulos para el mantenimiento de la patogénesis de la preeclampsia. Resumen en inglés Objective: To examine the ultrastructure of the syncytiotrophoblast in placentae of pregnant woman with pre-eclampsia is the objetive of this work with special reference to the effect of hypoxia on the fine structure of the tissue. Method: Ten placentae at term affected by pre-eclampsia were taken immediately after delivery by caesarea and from each one three biopsies from maternal surface were dissected in delivery room in specimens of 2 a 5 mm and fixed by immersion in (mas) 4 % glutaraldeyde - 0.1 M phosphate buffer, pH 7.4, at 4° C. Later, they were divided into 1- mm fragments and immersed in a fresh similar solution for periods varying from 2 to 72 hours followed by secondary fixation in 1 % osmium tetroxide - 0.1 M phosphate buffer for 1 hour. The samples were processed according to the conventional procedures of transmission electron microscopy for their observation. Setting: Laboratory of electron microscopy from CIADANA, Faculty of Sciences of Health, Maracay. Results: The findings reveal prolongations of the plasmamembrane or microvilli of the syncytium of different forms which seem release of the surface. The basal membrane of the syncytium appeared thickened. Swollen mitochondria in diverse degenerative grade were seen with particles electron dense in their matrix. Apical regions of cytoplasm seem detach to maternal circulation. Numerous intracytoplasmic vacuoles and dilated cisterns of the rough endoplasmic reticulum were seen into cytoplasm. Interruptions of the syncytial plasmamembrane and regions of cytoplasm withouth plasma membrana were observed. Conclusion: Fragments of syncytium detached from trophoblast surface suggest to be the corpuscles that damage the endothelium of the unity placental - feto - maternal and can be the stimulus to the perturbation of endothelial cell function in the pathogenesis of pre-eclampsia.

Scientific Electronic Library Online (Spanish)

2

α-particle production in the scattering of He-6 by Pb-208 at energies around the Coulomb barrier

Escrig, Diego; Sánchez-Benítez, A. M.; Moro, Antonio M.; González Álvarez, Marcos A.; Andrés, María Victoria; Angulo, C.; García Borge, María José; Cabrera, J.; Cherubini, S.; Demaret, P.; Espino, José Manuel; Figuera, P.; Freer, M.; García Ramos, José Enrique; Gómez Camacho, Joaquín; Gulino, Marisa; Kakuee, O. R.; Martel, Ismael; Metelko, C.; Pérez-Bernal, F.; Rahighi, J.; Rusek, K.; Smirno, D.; Tengblad, Olof; Ziman, V.
2007-06-07

Digital.CSIC (Spain)

3

α-particle production in the scattering of 6He by 208Pb at energies around the Coulomb barrier

Escrig, Diego; Sánchez-Benítez, A. M.; Moro, A. M.; González Álvarez, Marcos A.; Andrés, María Victoria; Angulo, C.; García Borge, María José; Cabrera, J.; Cherubini, S.; Demaret, P.; Espino, José Manuel; Figuera, P.; Freer, M.; García Ramos, José Enrique; Gómez Camacho, Joaquín; Gulino, M.; Kakuee, O. R.; Martel, Ismael; Metelko, C.; Pérez-Bernal, F.; Rahighi, J.; Rusek, K.; Smirnov, D.; Tengblad, O.; Ziman, V.
2007-11-29

Digital.CSIC (Spain)

5

The t+n+n system and H-5

Meister, M.; Chulkov, L. V.; Simon, H.; Aumann, T.; García Borge, María José; Elze, Th. W.; Emling, H.; Geissel, H.; Hellström, M.; Jonson, B.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Markenroth, K.; Münzenberg, G.; Nickel, F.; Nilsson, T.; Nyman, G.; Pribora, V.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Tengblad, Olof; Zhukov, M. V.
2003-10-16

Digital.CSIC (Spain)

6

The outburst of the κ Cygnids in 2007: clues about the catastrophic break up of a comet to produce an Earth-crossing meteoroid stream

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.
2009-01-01

Digital.CSIC (Spain)

7

Testing of a DSSSD detector for the stopped RISING project

Kumar, R.; Molina, Francisco G.; Pietri, S.; Casarejos, E.; Algora, Alejandro; Benlliure, J.; Doornenbal, P.; Gerl, J.; Gorska, M.; Kojouharov, I.; Podolyak, Z.; Prokopowicz, W.; Regan, P. H.; Rubio, Berta; Schaffner, H.; Tashenov, S.; Wollersheim, H. J.
2008-11-01

Digital.CSIC (Spain)

9

Study of the unstable nucleus Li-10 in stripping reactions of the radioactive projectiles Be-11 and Li-11

Zinser, M.; Humbert, F.; Nilsson, T.; Schwab, W.; Blaich, Th.; García Borge, María José; Chulkov, L. V.; Eickhoff, H.; Elze, Th. W.; Emling, H.; Franzke, B.; Freiesleben, H.; Geissel, H.; Grimm, K.; Guillemaud-Mueller, D.; Hansen, P.G.; Holzmann, R.; Imich, H.; Jonson, B.; Keller, J. G.; Klepper, O.; Klingler, H.; Kratz, J. V.; Kulessa, R.; Lambrecht, D.; Leifels, Y.; Magel, A.; Mohar, M.; Mueller, A. C.; Münzenberg, G.; Nickel, F.; Nyman, G.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Sherrill, B. M.; Simon, H.; Stelzer, K.; Stroth, J.; Tengblad, Olof; Trautmann, W.; Wajda, E.; Zude, E.
1995-08-28

Digital.CSIC (Spain)

10

Study of the dependence of direct soft photon production on the jet characteristics in hadronic Z (0) decays

DELPHI Collaboration; Abdallah, J.; Costa, María José; Ferrer, Antonio; Fuster, Juan; García García, Carmen; Oyanguren, Arantza; Perepelitsa, Vassil; Salt, José; Tortosa, Pablo
2010-06-01

Digital.CSIC (Spain)

11

Structure of neutron-rich oxygen isotopes

Cortina-Gil, D.; Fernández-Vázquez, J.; Aumann, T.; Baumann, T.; Benlliure, J.; García Borge, María José; Chulkov, L. V.; Datta Pramanik, U.; Forssén, C.; Fraile, Luis M.; Geissel, H.; Gerl, J.; Hammache, F.; Itahashi, K.; Janik, R.; Jonson, B.; Mandal, S.; Markenroth, K.; Meister, M.; Mocko, M.; Muenzenberg, G.; Ohtsubo, T.; Ozawa, A.; Prezado, Yolanda; Riisager, K.; Scheit, H.; Schneider, R.; Schrieder, G.; Simon, H.; Sitar, B.; Stolz, A.; Strmen, P.; Suemmerer, K.; Szarka, I.; Weick, H.
2005-09-12

Digital.CSIC (Spain)

13

Shell structure of the near-dripline nucleus O-23

Cortina-Gil, D.; Fernández-Vázquez, J.; Aumann, T.; Baumann, T.; Benlliure, J.; García Borge, María José; Chulkov, L. V.; Datta Pramanik, U.; Forssén, C.; Fraile, Luis M.; Geissel, H.; Gerl, J.; Hammache, F.; Itahashi, K.; Janik, R.; Jonson, B.; Mandal, S.; Markenroth, K.; Meister, M.; Mocko, M.; Münzenberg, G.; Ohtsubo, T.; Ozawa, A.; Prezado, Yolanda; Pribora, V.; Riisager, K.; Scheit, H.; Schneider, R.; Schrieder, G.; Simon, H.; Sitar, B.; Stolz, A.; Strmen, P.; Sümmerer, K.; Szarka, I.; Weick, H.
2004-08-06

Digital.CSIC (Spain)

14

Proton-proton correlations observed in two-proton decay of 19Mg and 16Ne

Mukha, I.; Grigorenko, L.; Summerer, K.; Acosta, L.; Álvarez, M. A. G.; Casarejos, E.; Chatillon, A.; Cortina-Gil, D.; Espino, José Manuel; Fomichev, A.; García Ramos, José Enrique; Geissel, H.; Gómez Camacho, Joaquín; Hofmann, J.; Kiselev, O.; Korsheninnikov, A.; Kurz, N.; Litvinov, Yu.; Martel, Ismael; Nociforo, C.; Ott, W.; Pfutzner, M.; Rodríguez-Tajes, C.; Roeckl, E.; Stanoiu, M.; Weick, H.; Woods, P. J.
2008-02-28

Digital.CSIC (Spain)

15

Outburst activity in comets-II. A multiband photometric monitoring of comet 29P/Schwassmann-Wachmann 1

Trigo-Rodríguez, J. M.; García-Hernández, D. A.; Sánchez, A.; Lacruz, J.; Davidsson, B. J. R.; Rodríguez, D.; Pastor, S.; Reyes, J. A. de los
2010-01-01

Digital.CSIC (Spain)

16

Oncoides tipo Osagia en la Formación La Manga (Oxfordiano) y su significado paleoecológico, arroyo La Vaina, Mendoza/ Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza

Palma, R.M.; Bressan, G.S.; Kietzmann, D.A.
2007-03-01

Resumen en español Oncoides microbianos fueron encontrados en calizas del Oxfordiano de la Formación La Manga en la sección del Arroyo La Vaina, provincia de Mendoza. Los oncoides se presentan en packstones, floatstones-rudstones o dispersos en wackestones. Presentan formas elípticas, ameboidales y esféricas. Se reconocieron diferentes tipos de oncoides de acuerdo a las características de sus envolturas: (1) laminaciones micríticas, (2) laminaciones grumosas, y (3) laminaciones con or (mas) ganismos incrustantes. Sus núcleos están representados por fragmentos de moluscos, equinoideos, peloides e intraclastos. La envoltura sigue la forma del núcleo en la zona interna de la corteza. Sin embargo, en las zonas externas, la laminación contiene organismos incrustantes dominados por nubeculáridos y serpúlidos. Algunos oncoides, especialmente las formas ameboidales y elípticas, están caracterizados por múltiples núcleos, representados por oncoides pequeños. Los oncoides aparecen conjuntamente con bivalvos, equinodermos, foraminíferos y serpúlidos. La fauna indica condiciones someras, tranquilas, y la excelente preservación de los equinodermos sugiere mínimo transporte antes del enterramiento. Los oncoides crecieron en un ambiente marino normal, en el sector submareal, de aguas someras, con agitación leve a moderada. El limitado rolido en el crecimiento de los oncoides probablemente fue acompañado por corrientes intermitentes que reorientaron los oncoides paralelos a la estratificación. La laminación discontinua con organismos incrustantes refleja períodos de no agitación y litificación que facilitaron el crecimiento de organismos incrustantes sobre oncoides estáticos durante un período de baja tasa de sedimentación. La depositación de calizas con oncoides ocurrió durante la somerización del intervalo carbonático, asociada con la emersión, exposición subaérea y desarrollo de un paleokarst, como consecuencia de fluctuaciones relativas del nivel del mar. Resumen en inglés Microbial oncoids have been found in the Oxfordian limestones of the La Manga Formation in the La Vaina section at Potimalal River, Mendoza province. The oncoids ocurr either in packstone or floatstone-rudstone or are scattered in the wackestones. They are mostly elliptical, ameboidal and subordinately spherical in shape. Different types of oncoids were recognized, according to their features of envelopes: (1) micritic laminations, (2) grumose laminations, and (3) organis (mas) m-bearing laminations. Molluscs and echinoid fragments, peloids, and intraclasts acted as oncoid nuclei. Laminae follow the shape of nuclei, especially in the inner zone of the cortices. However, in the outer zones the laminae contain encrusting organisms dominated by nubeculariids and serpulids. Some oncoids, especially the ameboidal or elliptical forms, are characterized by multiple nuclei, represented by small oncoids. The oncoids are associated with bivalves, echinoderms, forams, and serpulids. The fauna is indicative of calm, shallow conditions and the excellent preservation of echinoderms suggests minimal transport prior to burial. Growth histories are in evidence. The oncoids grew in a shallow, low energy, slightly to moderate agitated subtidal normal sea water environment. The limited rolling growth oncoids was probably accompanished by intermittent currents that reoriented the oncoids parallel to stratification. The discontinuous organisms-bearing laminations reflect periods of non-agitation and litification, which facilitated the growth of encrusting organisms on static oncoid particles during a period of low sedimentation rate. Deposition of the oncoidbearing limestones took place during shallowing of the carbonate interval and associated with emersion, subaerial exposition and paleokarst as consequence of sea level fluctuations.

Scientific Electronic Library Online (Spanish)

17

Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Keller, H. U.; Küppers, M.; Fornasier, S.; Gutiérrez, Pedro J.; Hviid, Stubbe F.; Jorda, L.; Knollenberg, Jörg; Lowry, Stephen C.; Rengel, Miriam; Bertini, Ivano; Cremonese, Gabriele; Wing, Ip; Koschny, Detlef; Kramm, Rainer; Kührt, E.; Lara, Luisa María; Sierks, Holger; Thomas, Nicolas; Barbieri, Cesare; Lamy, P.; Rickman, Hans; Rodrigo Montero, Rafael; A’Hearn, Michael F.; Angrilli, Francesco; Barucci, M. A.; Bertaux, Jean-Loup; Deppo, Vania da; Davidsson, B.; Cecco, Mariolino de; Debei, Stefano; Fulle, M.; Gliem, Fritz; Groussin, O.; López-Moreno, José Juan; Marzari, Francesco; Naletto, Giampiero; Sabau-Graziati, L.; Sanz Andrés, Ángel; Wenzel, Klaus-Peter
2007-03-01

Digital.CSIC (Spain)

18

Nostoc cyanobacterial inoculation in South African agricultural soils enhances soil structure, fertility, and maize growth

Maqubela, M. P.; Mnkeni, P. N. S.; Malam Issa, O.; Pardo Fernández, María Teresa; D’Acqui, L. P.
2009-01-01

Digital.CSIC (Spain)

20

Measurement of the k(T) Distribution of Particles in Jets Produced in p(p)over-bar Collisions at root s = 1.96 TeV

CDF Collaboration; Cabrera, Susana; Cuenca Almenar, Cristóbal; Álvarez González, B.; Casal, Bruno; Cuevas, Javier; Gómez, G.; Rodrigo, Teresa; Ruiz, Alberto; Scodellaro, Luca; Vila, Iván; Vilar, Rocío; Aaltonen, T.
2009-06-12

Digital.CSIC (Spain)

21

Measurement of the absolute branching fractions for D-s(-) -> l(-) (nu)over-bar(l) and extraction of the decay constant f(Ds)

Babar Collaboration; López- March, Neus; Martínez-Vidal, Fernando; Milanés, Diego A.; Oyanguren, Arantza; Sánchez, P. D.; Lees, J. P.
2010-11-10

Digital.CSIC (Spain)

22

Isospin mixing and energy distributions in three-body decay

Garrido, Eduardo; Fedorov, D.V.; Fynbo, H.O.U.; Jensen, A.S.
2007-03-23

Digital.CSIC (Spain)

23

Investigation of colour reconnection in WW events with the DELPHI detector at LEP-2

Piedra, Jonatan; Martínez-Rivero, Celso; Rivero, M.; Costa, María José; Matorras, Francisco; Cuevas, Javier; Oyanguren, Arantza; Marco, Jesús; Tortosa, Pablo; Ferrer, Antonio; Salt, José; Marco, Rafael; García García, Carmen; Gómez-Ceballos, Guillelmo; Rodríguez, David; Fuster, Juan; Marín, J. C.; López, Juan M.; Fernández, Javier
2007-05-05

Digital.CSIC (Spain)

24

Invariant-mass spectroscopy of Li-10 and Li-11

Zinser, M.; Humbert, F.; Nilsson, T.; Schwab, W.; Simon, H.; Aumann, T.; García Borge, María José; Chulkov, L. V.; Cub, J.; Elze, Th. W.; Emling, H.; Geissel, H.; Guillemaud-Mueller, D.; Holzmann, R.; Irnich, H.; Jonson, B.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Lenske, H.; Magel, A.; Mueller, A. C.; Münzenberg, G.; Nickel, F.; Nyman, G.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Stelzer, K.; Stroth, J.; Surowiec, A.; Tengblad, Olof; Wajda, E.; Zude, E.
1997-06-16

Digital.CSIC (Spain)

25

Invariant mass spectrum and alpha-n correlation function studied in the fragmentation of He-6 on a carbon target

Aleksandrov, D.; Aumann, T.; Axelsson, L.; Baumann, T.; García Borge, María José; Chulkov, L. V.; Cub, J.; Dostal, W.; Eberlein, B.; Elze, Th. W.; Emling, H.; Geissel, H.; Goldberg, V. Z.; Golovkov, M.; Grünschloß, A.; Hellström, M.; Holeczek, J.; Holzmann, R.; Jonson, B.; Korshenninikov, A. A.; Kratz, J. V.; Kraus, G.; Kulessa, R.; Leifels, Y.; Leistenschneiderg, A.; Leth, T.; Mukha, I.; Münzenberg, G.; Nickel, F.; Nilsson, T.; Nyman, G.; Petersen, B.; Pfützner, M.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Schwab, W.; Simon, H.; Smedberg, M. H.; Steiner, M.; Stroth, J.; Surowiec, A.; Suzuki, T.; Tengblad, Olof; Zhukov, M. V.
1998-04-13

Digital.CSIC (Spain)

26

Implication of the C terminus of the Prunus necrotic ringspot virus movement

Aparicio, Frederic; Pallás, Vicente; Sánchez-Navarro, J. A.
2010-03-10

Digital.CSIC (Spain)

28

He-8 - He-6: a comparative study of electromagnetic fragmentation reactions

Meister, M.; Markenroth, K.; Aleksandrov, D.; Aumann, T.; Baumann, T.; García Borge, María José; Chulkov, L. V.; Cortina-Gil, D.; Eberlein, B.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellström, M.; Jonson, B.; Kratz, J. V.; Kulessa, R.; Leistenschneider, A.; Mukha, I.; Münzenberg, G.; Nickel, F.; Nilsson, T.; Nyman, G.; Pfützner, M.; Pribora, V.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Simon, H.; Tengblad, Olof; Zhukov, M. V.
2002-03-25

Digital.CSIC (Spain)

29

Halo excitations in fragmentation of He-6 at 240 MeV/u on carbon and lead targets

Aleksandrov, D.; Aumann, T.; Axelsson, L.; Baumann, T.; García Borge, María José; Chulkov, L. V.; Cub, J.; Dostal, W.; Eberlein, B.; Elze, Th. W.; Emling, H.; Geissel, H.; Goldberg, V. Z.; Grünschloß, A.; Hellström, M.; Holeczek, J.; Holzmann, R.; Jonson, B.; Kratz, J. V.; Kraus, G.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Leth, T.; Markenroth, K.; Meister, M.; Mukha, I.; Münzenberg, G.; Nickel, F.; Nilsson, T.; Nyman, G.; Petersen, B.; Pfützner, M.; Pribora, V.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Schwab, W.; Simon, H.; Smedberg, M. H.; Stroth, J.; Surowiec, A.; Tengblad, O.; Zhukov, M. V.
2000-04-10

Digital.CSIC (Spain)

30

Evolución de la litiasis residual post-LEOC en función del tipo de cálculo y de la composición de la orina/ Evolution of post-ESWL residual lithasis depending on the type of calculus and urine composition

Grases, Félix; Costa-Bauzá, Antonia; Isern, Bernat; Sanchis, Pilar; Perelló, Joan; Hierro, Fernando; Conte Visus, Antonio
2009-08-01

Resumen en español Objetivos: La eliminación de cálculos renales mediante ondas de choque (LEOC) suele dar buenos resultados, aunque no siempre se consigue la expulsión completa de los fragmentos generados, que pueden inducir nuevos episodios litiásicos. Así, se considera que entre el 10 y el 26% de los cálculos fragmentados pueden experimentar procesos de re-crecimiento. En este trabajo se presenta un estudio "in vitro" de la influencia de la composición del fragmento y de la orina (mas) en el crecimiento de los fragmentos post-LEOC, con la finalidad de conocer los efectos de ambos parámetros, valorar su importancia y así poder plantear medidas profilácticas efectivas. Métodos: Para ello se seleccionaron fragmentos post-LEOC de cálculos de oxalato cálcico monohidrato (24), oxalato cálcico dihidrato (48), hidroxiapatita (24) y ácido úrico (16). Todos los fragmentos utilizados fueron expulsados el mismo día de la aplicación de las ondas de choque. Resultados: En todas las situaciones, los fragmentos de cálculos estudiados presentaron una notable capacidad para inducir el crecimiento del oxalato cálcico o/y fosfato cálcico, de manera que en condiciones de normocalciuria se generaron cristales de oxalato cálcico monohidrato (COM), con hipercalciuria y pH inferior a 6.0 crecieron cristales de COM y oxalato cálcico dihidrato (COD) y en condiciones de hipercalciuria y pH superior a 6.0 crecieron cristales de hidroxiapatita (HAP) y brushita (BRU). Es de destacar que las velocidades de crecimiento más elevadas se observaron sobre fragmentos de COD, en condiciones de hipercalciuria y pH = 6.5, y le siguen en orden de magnitud las velocidades de crecimiento sobre fragmentos de COM y HAP en condiciones de hipercalciuria y pH = 6.5. Las demás velocidades de crecimiento son parecidas y del orden de 10 veces inferiores a las primeras. En cuanto al papel de los inhibidores de la cristalización, el fitato exhibió efectos muy notables en todas las condiciones ensayadas. El citrato, sin embargo, incluso para elevadas concentraciones (1000 mg/L), manifestó efectos inhibidores débiles. Conclusiones: Estos estudios demuestran la importancia de evitar la retención de nucleantes heterogéneos (micropartículas sólidas preexistentesj en las cavidades renales ya que actúan muy eficazmente como inductores de la formación de nuevos cálculos, cuya composición depende en gran medida de la composición de la orina. Resumen en inglés Objectives: Extracorporeal shock wave lithotripsy (ESWL) is one of the most commonly used procedures for removal of renal calculi from the upper urinary tract, but complete expulsion of the fragments generated is not always achieved. This can lead to new lithiasic episodes, and it is considered that 10-26% of fragmented calculi can undergo regrowth. This in vitro study investigated the influence of fragment and urinary composition on post-ESWL growth of fragments, with th (mas) e aims of establishing the effect and importance of these parameters, and identifying effective prophylactic measures. Methods: Fragments collected from patients immediately following expulsion after ESWL treatment were selected for regrowth experiments. The particles included 24 calcium oxalate monohydrate (COM) fragments, 48 calcium oxalate dihydrate (COD), 24 hydroxyapatite (HAPj, and 16 uric acid. Results: In all treatments, calculi fragments showed a considerable capacity to induce growth of calcium oxalate and calcium phosphate. Under normocalciuria conditions, new COM crystals formed; both COM and COD crystals developed under hypercalciuria conditions at a urinary pH 6.0 both HAP and brushite (BRU) crystals were formed. The highest growth rates were observed for COD calculi fragments under hyper-calciuria conditions and at a urinary pH of 6.5, followed by growth on COM and HAP fragments under the same conditions; growth rates under other conditions tested were similar but 10-fold lower. With regard to the role of crystallization inhibitors, phytate exhibited inhibitory effects under all assay conditions. However, citrate had little effect, even at the highest concentration tested (1,000 mg/L). Conclusions: This study demonstrates the importance of avoiding heterogeneous nucleant retention (preexisting solid microparticlesj in renal cavities, as these can act as very efficient inducers of the formation of new calculi, the composition of which is mainly dependant on the urine composition.

Scientific Electronic Library Online (Spanish)

31

Estudio PIXE y PIGE de gemas en el Tesoro de Torredonjimeno

Gutiérrez, P. C.; Perea Caveda, Alicia; Ynsa, M. D.; Climent-Font, A.
2008-01-01

Digital.CSIC (Spain)

32

Estructuras de deformación (¿sismitas?) en la Formación Río Negro, provincia de Río Negro, Argentina

Schillizzi, Roberto; Luna, Liliana; Falco, Juan Ignacio
2010-07-01

Resumen en español A Las estructuras de deformación (ED) en sedimentos blandos comprenden las alteraciones que se producen casi simultáneamente con la sedimentación. Estos procesos se hallan en relación directa con las características internas de los materiales sedimentarios y de los factores externos que actúan sobre ellos. Sus resultados incluyen deformaciones como inyecciones, fracturas, volcanes y laminaciones convolutas que afectan total o parcialmente la estratificación. Los se (mas) dimentos blandos deformados por sismos se incluyen bajo la denominación general de sismitas (seismites). Como objetivo de esta investigación se plantea reconocer, por primera vez, estructuras de deformación ubicadas en la Formación Río Negro presentes en el sector norte del Golfo San Matías, en inmediaciones del Faro Río Negro. La metodología empleada consistió en el reconocimiento y descripción de las estructuras, para lo cual se extrajeron muestras para determinar granulometría, mineralogía y contenido de materia orgánica. Se fotografiaron los distintos sectores con deformaciones con el fin de establecer modelos comparativos. El sector estudiado, de 4 km de extensión, se ubica entre el faro de Río Negro y el inicio del Banco Verde y morfológicamente corresponde a un frente acantilado con orientación ENE-OSO. En él se determinaron las siguientes ED: a- de carga simple, pseudonódulos contiguos y aislados, y estructuras complejas; b- de escape de fluidos y c- estructuras de deslizamiento basal y por presión dirigida. El origen de las deformaciones se debe a las características de las sedimentitas y a los procesos que las afectan tales como los efectos por carga, escapes de fluidos y las presiones dirigidas. Como origen de estos procesos se señalan: la presión de la columna litológica, las olas de tormentas y los terremotos. Por los rasgos hallados las deformaciones del litoral rionegrino tendrían un origen sísmico, proceso ocurrido en un único evento durante el ciclo Andino cuyos inicios se fijan hace aproximadamente 45 Ma. Por otra parte sus techos y bases no se hallan asociados a otros procesos de deformación y sus espesores no exceden el metro de potencia. Además se hallan acotadas a la zona de transición entre los miembros medio y superior de la Formación Río Negro descansando en algunos casos sobre arcilitas y en otros sobre limolitas, originadas en un paleorelieve de interdunas. Resumen en inglés Soft-sediment deformation structures (SSD) are alterations produced almost simultaneously with sedimentation. They are directly related to internal characteristics of sedimentary materials as well as to external factors acting on them. Results derived from such alterations are evidenced as injections, fractures, volcanoes and convolute laminations, among other forms, affecting stratification either totally or partially. Soft-sediment deformation structures resulting from (mas) seisms are known as seismites. The present study aims at determining for the first time the presence of SSD structures in the Río Negro Formation, located in the northern area of San Matías Gulf, near Río Negro Lighthouse, Argentina (Fig. 1). To this end, structures were firstly identified and further described. Samples were subsequently collected for the determination of grain-size, mineralogy and organic matter content. Photographs of the different sectors evidencing deformations were taken in order to determine further comparative models. Morphology in the study area is associated to cliffs with vertical, fractured fronts and with an average height of 70 m in whose base torn-down blocks are accumulated. The geological structure of the study area is related to the Cuenca del Colorado and the Comarca Nordpatagónica, whose basement is mainly composed of Paleozoic and Mesozoic crystalline rocks. The sedimentary tertiary cover from the Miocene-Pliocene is represented by light-blue sandstones of the Río Negro Formation (Andreis, 1965). This unit was formed in an aeolian environment with intercalations of clay-silt shallow lagoons and a marine episode located in the mid area of the Río Negro Formation. At the top of the Río Negro Formation there are Pleistocene-Holocene sedimentites having a thickness of up to 5 m. Within the local structural framework of our study area there are fractures with a NE-SW and a NW-SE direction, which are related with fractures N55º, N90º and N350º azimuth located in the abrasion platform. According to Dzulinsky and Walton (1965), Lowe (1975), Brencley and Newall (1977), Clauss (1993), van Loon (2002), Owen (2003), Neuwerth et al. (2006), Alfaro et al. (2006), Montenat et al. (2007), among others (Table 1), and, taking into account the geometry of deformations, laboratory reconstructions and field observations from our study area, it can be concluded that the classifications of SSD structures tend to establish morphologic and genetic systematizations. The following characteristics were identified in our study area: limited deformations among stratigraphic horizons; a lateral continuity of SSD structures at considerable distances; and a confinement between non-deformed strata and its lithological association with psamitic-pelitic sediments. The study area, which is 4 km long and is located between Río Negro Lighthouse and the beginning of Banco Verde, is from the morphological point of view, a cliffed front with an ENE-WSW orientation. Different types of SSD structures were identified in this area. For example, from the morphological point of view and according to the loading mechanisms observed, simple-load structures (Fig. 2), attached and detached pseudonodules (Figs. 3, 4 and 5) and complex structures (Fig. 6) were identified. Furthermore, from the genetic point of view and according to the intrusion processes observed in soft sediments, water-scape structures (Fig. 7) and plate- or fountain-like deformations (Fig. 8) were found. From the genetic point of view, and based on the collapse and pressure mechanisms observed, basal slumping (Fig. 9) and directed-pressure structures (Fig. 11) were also found. The above-mentioned SSD structures were analyzed and interpreted following Strachan´s model (2002) (Fig. 10) and Laird´s model (1968) (Fig. 12). The origin of SSD structures depends on the characteristics of sedimentites and on the mechanisms that produce them. In the study area, the materials susceptible to deformation come from an interdune environment that is characterized by granulometric variations derived from the fluctuating and restrictive climatic conditions (Cojan and Thiry, 1992) that typify the Río Negro Formation. Fine-grained materials having low cohesion and poor sorting such as the sediments of deformed strata (Fig. 13) produced SSD structures as a result of high pore pressure and liquefaction effects (Tsuchida and Hayashi, 1971; Obermeier, 1996). Grain packing with a porous value as that allows intercommunication among grains and saturated material, is also crucial to the formation of SSD structures. The mineralogic content of deformed levels is composed of i) quartz, chalcedony, orthose, plagioclase, pyroxenes and biotite, opaques (magnetite and ilmenite, autigenic pyrite) in crystalline aggregates; ii) undetermined Fe oxides; and iii) colorless and light-brown unaltered volcanic glass shards, clays identified as smectite-illite interstratified and scarce kaolinite. Grains are mainly subangular and, to a lesser extent, sub-round and round. The surface of the majority of grains in the study area was found clean and with some marks. The percentage of CaCO3 was found to vary from 0.5 to 3% and that of total organic carbon (TOC) was found to reach 1.5%. Deformations may be produced as a result of load deformation mechanisms, fluid escape, basal slumping or pressure-directed displacements. Due to load deformation mechanisms, structures are linked to gravity-related movements occurring during the initial stages of deposition. For these deformations to occur, grain-size at the overlaying levels should be thicker than at the underlying levels, for example, sandstones rather than silstones or claystones. These deformations are related to water saturation at the deformed level (fluidization-liquefaction). Therefore, deformation mechanisms, which involve both expulsion and rotation of fragments as well as fluid escape, are characterized by the action of lithostatic pressure which produces movement (deformation) and by the action of the underlying sedimentary levels. Deformations may also result from a fluid escape mechanism, i.e., from a mechanism associated to i) the spatial arrangement of grains (packing), ii) their shape, iii) their tendency to inequigranularity, and iv) the communication among macro- and micro- pores as well as the high or low sinuosity connection among themselves (Net and Limarino, 2000). Further requirements for deformations to occur include particular thixotrophic conditions, especially the presence of colloids among grains. The rupture of unions of particles either by hitting or by shearing is, among others, a cause which produces an unbalance between hydrostatic pressure and lithostatic pressure. If the latter is altered, the energetic unbalance makes fine sediments flow among the weakly lithified sandstones whose extrusion will occur via both vertical and horizontal pore ducts (Lopez Gamundi, 1986; Clauss, 1993). Basal slumping produces deformations that are associated not only to soft sediments deposited in natural slopes but also to interbedded sand- and mud-levels. Layers tend to have a prismatic-shaped geometry whose materials are under ductile-to-fragile conditions, in which antique layers support younger ones. Once horizontality is affected, movement, which is marked by a rupture of the original slope, begins. The lower levels are expected to transport the upper ones without affecting the original succession of layers. At the delay of movement derived from the compressive effect of the displacement front, fluids extrude forming cones or cut dikes (Fig. 10). Several deformations of this type initiate movement as result of differences in the hydrostatic gradient (Strachan, 2002). Deformations may be also produced as a result of pressure-directed displacements which are conditioned by the compaction level, thickness and ability of materials to deform. Thus, deformations occur because the original level is saturated in water as a result of the ductile behavior of materials (Bracco et al., 2005). Laird (1968) claims that SSD structures should meet some of the following requirements to be considered of seismic origin: slightly curved strata walls and floors to follow the original stratification and interruption of continuity of the stratum that is marked by a scar in which the sedimentary fillings keep their characteristics both above and below stratification. There could be rotated sediment clasts below the discontinuity as a result of a thrust-induced drag of the upper sedimentary packing. These processes could be, in turn, triggered either by the charge or pressure of the lithologic column, storm waves and seismicity. Storm-wave impact may also produce deformation in soft sediments. Nonetheless, no high energy structures such as cross-beddings or tsunami-type chaotic sedimentation were observed in our study area. Noteworthingly, for stormwave-derived liquefaction to occur, waves should reach magnitudes higher than 6 m (Alfaro et al., 2002), this being a phenomenon that was not recorded in our study area. Taken together, findings from the present study indicate that SSD structures in our study area are seismic alterations that occurred in an event during the Andean cycle whose beginnings are traced approximately 45 My ago. The fact that i) both the roofs and bottoms of these structures are not associated to other processes of deformation, ii) their thickness does not exceed one meter, and iii) they are confined to a transitional area between the middle and top members of the Río Negro Formation, lying in some cases on claystones and in some other cases, on siltstones, originated in an interdune paleorelief, confirms their seismic origin.

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Coupling of valence particles/holes to 68,70Ni studied via measurements of the B(E2) strength in 67,69,70Ni and 71Cu

Mach, H.; Lewitowicz, M.; Stanoiu, M.; Becker, F.; Blomqvist, J.; García Borge, María José; Boutami, R.; Cederwall, B.; Dlouhy, Z.; Fogelberg, B.; Fraile, Luis M.; Georgiev, G.; Grawe, H.; Grzywacz, R.; Johansson, P. I.; Klamra, W.; Lukyanov, S.; Mineva, M.; Mrazek, J.; Neyens, G.; Oliveira Santos, F. de; Pfützner, M.; Penionzhkevich, Yu. E.; Ramström, E.; Sawicka, M.
2003-05-19

Digital.CSIC (Spain)

34

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1984-01-01

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35

Cinética de carbonatación de morteros experimentales de cal de tipo romano

Sánchez-Moral, S.; García Guinea, Javier; Luque, L.; González-Martín, R.; López-Arce, Paula
2004-09-30

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37

3D structure of the C3bB complex provides insights into the activation and regulation of the complement alternative pathway convertase

Torreira, Eva; Tortajada, Agustín; Montes, Tamara; Rodríguez de Córdoba, Santiago; Llorca, Óscar
2009-01-09

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