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Search Results: 1 - 10 of 41357 matches for " Juan Iba?ez "
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3D Reconstruction with Spiral Computed Tomography in Choroidal Osteoma  [PDF]
Francisco Javier Ascaso, Laura Herrera, Laura Villén, Rafael Lasierra, Juan Ibaez, Diana Pérez, José Angel Cristóbal
Open Journal of Ophthalmology (OJOph) , 2013, DOI: 10.4236/ojoph.2013.31002
Abstract:

Choroidal osteoma (CO) is a rare, ossifying benign tumor originated in the choroid that typically occurs in otherwise healthy young women (1,2). It is characterized by a yellowish, well demarcated lesion in the juxtapapillary or macular area. The diagnosis is clinical and can be confirmed with the use of fluorescein or indocyanine angiography, optical coherence tomography, computed tomography or magnetic resonance imaging. Choroidal neovascularization or subretinal fluid, the main causes for vision loss, can be treated with laser therapy, photodynamic therapy or intravitreal antivascular endothelial growth factor therapy. We present a case of choroidal osteoma, showing the role of the high resolution 3D spiral computed tomography.

El uso del utillaje en piedra en el final del Paleolítico Superior Peninsular
Jesus González Urquijo,Juan José Ibaez Estévez
Munibe Antropologia-Arkeologia , 2005,
Abstract: En este artículo se presenta un balance de los estudios sobre la función del utillaje de piedra tallado en el final del paleolítico superior, en el ámbito pirenaico y cantábrico. En él se discuten los distintos niveles de inferencia en los que participa esta información desde las tecnicas (el reconocimiento de útiles usados, las relaciones entre forma y función, la organización tecnologica de la industria litica, los procesados en otras materias) hasta la organización social y económica de los grupos de cazadores-recolectores (gestión del espacio, funcionalidad de las ocupaciones, planificación de las actividades, etc.)
Stability of toroidal magnetic fields in stellar interiors
Juan C. Ibaez-Mejia,Jonathan Braithwaite
Physics , 2015, DOI: 10.1051/0004-6361/201424469
Abstract: We present 3D MHD simulations of purely toroidal and mixed poloidal-toroidal magnetic field configurations to study the behavior of the Tayler instability. For the first time the simultaneous action of rotation and magnetic diffusion are taken into account and the effects of a poloidal field on the dynamic evolution of unstable toroidal magnetic fields is included. In the absence of diffusion, fast rotation (rotation rate compared to Alfv\'en frequency) is able to suppress the instability when the rotation and magnetic axes are aligned and when the radial field strength gradient p < 1.5. When diffusion is included, this system turns unstable for diffusion dominated and marginally diffusive dominated regions. If the magnetic and rotation axes are perpendicular to each other the stabilizing effect induced by the Coriolis force is scale dependent and decreases with increasing wavenumber. In toroidal fields with radial field gradients bigger than p > 1.5, rapid rotation does not suppress the instability but instead introduces a damping factor to the growth rate in agreement with the analytic predictions. For the mixed poloidal-toroidal fields we find an unstable axisymmetric mode, not predicted analytically, right at the stability threshold for the non-axisymmetric modes; it has been argued that an axisymmetric mode is necessary for the closure of the Tayler-Spruit dynamo loop.
The actin filament network associated to Sertoli cell ectoplasmic specializations
Cavicchia,Juan Carlos; Fóscolo,Mabel; Ibaez,Jorge; Lillig,Christopher; Capani,Francisco;
Biocell , 2011,
Abstract: junctional devices in sertoli cells conform the blood-testis barrier and play a key role in maturation and differentiation of germ cells. the spacial distribution of ectoplasmic specializations of sertoli cells was studied by β-actin immunolabelling, using laser confocal and transmission electron microscopy. for confocal microscopy, β-actin immunolabelling of ectoplasmic specializations was studied over the background of either prosaposin or glutaredoxin immunolabelling of the sertoli cytoplasm. labelling was found near the basal lamina, surrounding early spermatocytes (presumably in leptotene-zygotene) or at one of two levels in the seminiferous epithelium: (1) around deep infoldings of the sertoli cell cytoplasm, in tubular stages before spermiation, and (2) in the superficial part of the seminiferous epithelium, in tubular stages after or during spermiation. for transmission electron microscopy, β-actin immunolabelling of ectoplasmic specializations was also used. ectoplasmic specializations were found at two different levels of the seminiferous epithelium. we also used freeze fracture to analyze the characteristics of tubulo-bulbar complexes, a known component of apical ectoplasmic specializations. also, these different approaches allowed us to study the complex arrangement of the actin cytoskeleton of sertoli cells branches, which surround germ cells in different stages of the spermatogenic cycle. our results show a consistent labelling for β-actin before, during and after the release of spermatozoa in the tubular lumen (spermiation) suggesting a significant role of the actin network in spermatic cell differentiation. in conclusion, significant interrelations among the β-actin network, the junctional complexes of the blood-testis barrier and the ectoplasmic specializations were detected at different stages of the seminiferous cycle.
Differentiation and morphogenesis of Triatoma infestans (Klug 1834) female gonads: I - Post embryonic development
Ibaez de Barrett,Cecilia I.; Bozzini,Juan Pablo; Mariano de Bozzini,Marta;
Biocell , 2004,
Abstract: the post-embryonic development of the female gonads in triatoma infestans (hemiptera, heteroptera), insects of importance in health affairs as harbors and vectors of different tripanosomatidea flagellates, is presented in a complete follow-up since insect hatches from the egg up to the last molt in the fifth instar stage. the detailed description of the morphological changes which occur in each instar as well as careful measurements evaluating its size increase have been analyzed by stereomicroscopy, phase contrast, dark field, and oblique illumination, in order to optimize the observations as well the photographic register of gonad morphology and structure. the analysis was performed on gonad specimens obtained from broods no less than twenty (20) nymph bugs, reared at constant temperature and fed-up regularly. according to the results of our study we can assert that gonad differentiation takes place in early phases of the insect development. such is the case that first instars nymph’s present absolutely and easily recognizably male and female gonads. from the third instar on beside the filament region, the three zones in each ovariole body is distinguished, a differentiation that is more noticeable during the fourth instar where a definite organization is present at the vitelarium. such a clear cut zone development continues intensively during the fifth instar. finally at the end of such fifth nymph stage and when the last molt toward adults is prepared, clear signs of ovariole maturation take place since oocytes in early vitelogenesis are found.
A Simple Deterministic Lorenz Chaotic-Based Methodology to Cipher and Decipher Information
Suárez Casta?ón, Miguel S.;Aguilar Ibaez, Carlos;Martínez García, Juan C.;
Computación y Sistemas , 2007,
Abstract: we present a secure deterministic cipher and decipher mechanism based on the well-known lorenz dynamic system. the ciphering process is performed by the combination of the message to be ciphered and the states of the lorenz dynamic system, which act as the ciphering key. the deciphering process is implemented by the reconstruction of the key, which is generated using a lorenz system state observer. the observed key is then used in the decipher process in order to recover the ciphered message.
ESTUDIO DEL HUESO CLITORIDIANO CANINO
Ibaez,Marcelo; Ortega,Hugo; Galván,Stella M.; Lorente,Juan A.; Ferraro,Maria C.;
Revista chilena de anatomía , 1998, DOI: 10.4067/S0716-98681998000100013
Abstract: upon carrying out a bibliographical revision on the anatomical and histological structure of the canine clitoris, an important discrepancy between the consulted authors was verified, about the existence of the clitoridian bone in dogs. in the face of this alternative, it was decided to investigate on the existence of the structure in question. for that reason were dissected and processed histologically 23 canine clitoris. a meticulous description of the tissular constitution was made, not finding bony tissue in any case. in spite of this consideration that the number of processed samples, as well as the age of the studied animals, it is not the representative enough in order to assert the absence of this structure
Differentiation and morphogenesis of Triatoma infestans (Klug 1834) female gonads: I - Post embryonic development
Cecilia I. Ibaez de Barrett,Juan Pablo Bozzini,Marta Mariano de Bozzini
Biocell , 2004,
Abstract: The post-embryonic development of the female gonads in Triatoma infestans (Hemiptera, Heteroptera), insects of importance in health affairs as harbors and vectors of different tripanosomatidea flagellates, is presented in a complete follow-up since insect hatches from the egg up to the last molt in the fifth instar stage. The detailed description of the morphological changes which occur in each instar as well as careful measurements evaluating its size increase have been analyzed by stereomicroscopy, phase contrast, dark field, and oblique illumination, in order to optimize the observations as well the photographic register of gonad morphology and structure. The analysis was performed on gonad specimens obtained from broods no less than twenty (20) nymph bugs, reared at constant temperature and fed-up regularly. According to the results of our study we can assert that gonad differentiation takes place in early phases of the insect development. Such is the case that first instars nymph’s present absolutely and easily recognizably male and female gonads. From the third instar on beside the filament region, the three zones in each ovariole body is distinguished, a differentiation that is more noticeable during the fourth instar where a definite organization is present at the vitelarium. Such a clear cut zone development continues intensively during the fifth instar. Finally at the end of such fifth nymph stage and when the last molt toward adults is prepared, clear signs of ovariole maturation take place since oocytes in early vitelogenesis are found.
The actin filament network associated to Sertoli cell ectoplasmic specializations
Juan Carlos Cavicchia,Mabel Fóscolo,Jorge Ibaez,Christopher Lillig
Biocell , 2011,
Abstract: Junctional devices in Sertoli cells conform the blood-testis barrier and play a key role in maturation and differentiation of germ cells. The spacial distribution of ectoplasmic specializations of Sertoli cells was studied by β-actin immunolabelling, using laser confocal and transmission electron microscopy. For confocal microscopy, β-actin immunolabelling of ectoplasmic specializations was studied over the background of either prosaposin or glutaredoxin immunolabelling of the Sertoli cytoplasm. Labelling was found near the basal lamina, surrounding early spermatocytes (presumably in leptotene-zygotene) or at one of two levels in the seminiferous epithelium: (1) around deep infoldings of the Sertoli cell cytoplasm, in tubular stages before spermiation, and (2) in the superficial part of the seminiferous epithelium, in tubular stages after or during spermiation. For transmission electron microscopy, β-actin immunolabelling of ectoplasmic specializations was also used. Ectoplasmic specializations were found at two different levels of the seminiferous epithelium. We also used freeze fracture to analyze the characteristics of tubulo-bulbar complexes, a known component of apical ectoplasmic specializations. Also, these different approaches allowed us to study the complex arrangement of the actin cytoskeleton of Sertoli cells branches, which surround germ cells in different stages of the spermatogenic cycle. Our results show a consistent labelling for β-actin before, during and after the release of spermatozoa in the tubular lumen (spermiation) suggesting a significant role of the actin network in spermatic cell differentiation. In conclusion, significant interrelations among the β-actin network, the junctional complexes of the blood-testis barrier and the ectoplasmic specializations were detected at different stages of the seminiferous cycle.
ESTUDIO DEL HUESO CLITORIDIANO CANINO STUDY OF THE CANINE CLITORIDIAN BONE
Marcelo Ibaez,Hugo Ortega,Stella M. Galván,Juan A. Lorente
Revista chilena de anatomía , 1998,
Abstract: Upon carrying out a bibliographical revision on the anatomical and histological structure of the canine clitoris, an important discrepancy between the consulted authors was verified, about the existence of the clitoridian bone in dogs. In the face of this alternative, it was decided to investigate on the existence of the structure in question. For that reason were dissected and processed histologically 23 canine clitoris. A meticulous description of the tissular constitution was made, not finding bony tissue in any case. In spite of this consideration that the number of processed samples, as well as the age of the studied animals, it is not the representative enough in order to assert the absence of this structure
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