Search results for "PICO"
showing 10 items of 343 documents
Endoscopic findings in periapical surgery. A cross-sectional study of 206 roots
2022
A study is made of the findings of high-magnification rigid endoscopy at the root end surface following apicoectomy of teeth subjected to periapical surgery. A cross-sectional study was made of patients subjected to periapical surgery at the Unit of Oral Surgery and Implantology (University of Valencia, Valencia, Spain) between 2011 and 2019. Following apicoectomy, the root end surfaces were inspected, with the evaluation of untreated canals, isthmuses, craze lines, crack lines, opaque dentin and gaps. Likewise, an analysis was made of the association between patient age and the tooth type and restoration and the presence of craze lines, cracks, opaque dentin and gaps. The final sample cons…
Structure of the Cryptosporidium parvum microneme: a metabolically and osmotically labile apicomplexan organelle.
2003
From an EM study of thin sections, the rod-like microneme organelles within conventionally glutaraldehyde fixed Cryptosporidium parvum sporozoites have been shown to undergo a shape change to a more spherical structure when the sporozoites age in vitro for a period of approximately 12 to 24 h. This correlates with the shape change of intact sporozoites, from motile hence viable thin banana-shaped cells to swollen pear-shaped cells, shown by differential interference contrast light microscopy of unstained unfixed and glutaraldehyde-fixed samples, as well as by thin section EM of fixed sporozoites. From negatively stained EM specimens of unfixed and fixed sporozoites the cellular shape change…
Ultrastructure, fractionation and biochemical analysis of Cryptosporidium parvum sporozoites.
1999
Abstract Sporozoites of the apicomplexan parasite Cryptosporidium parvum were subjected to cell disruption and subcellular fractionation using a sucrose density step gradient. With this procedure, highly enriched preparations of the parasite membrane, the micronemes, dense granules and amylopectin granules were produced. No separate fraction containing rhoptries was obtained, however this organelle was found in defined fractions of the gradient, still associated with the apical tip of the sporozoites. Using negative staining, the internal structure of the micronemes was revealed by transmission electron microscopy. Micronemes and dense granules showed characteristic protein compositions by …
Exciton interactions in self-organised bacteriochlorophyll a - aggregates
2002
Exciton interactions of self-organised bacteriochlorophyll a - aggregates in non-polar solution linked via water and dioxane have been studied. Absorption and CD spectra of the aggregates show large red shifts typical of J-aggregates. Femtosecond excitation of the Qy band of the aggregates is followed by wavelength dependent non-exponential picosecond relaxation and anisotropy decay takes place in subpicosecond time scale. To explain these observations exciton theory and semi-empirical MO/CI calculations, that constitute the basis of the CIEM-approach developed by Linnanto et al. (J. Phys. Chem. B, 1999, 103B, 8739) was used. Structural models of aggregates were created by using the molecul…
Cuerpos, mujeres y embarazo en imágenes online. Fotografías en álbumes privados y en campañas del Ministerio de Salud de la Nación en Argentina
2018
El objetivo de este artículo es analizar entrevistas realizadas a 30 mujeres de 21 a 40 años de edad de sectores socioeconómicos medios y bajos y un corpus de sus fotografías publicadas online durante el proceso de su embarazo, poniéndolo en diálogo con las fotografías online del Ministerio de Salud de la Nación de campañas de cuidados de salud en el embarazo en Argentina. Nos interesa analizar ese recorte de la realidad, ese lugar donde se quiere echar luz, que implica la fotografía; sobre todo para poder identificar, analizar y comprender lo que se dejó afuera de ese recorte, lo que se intenta invisibilizar. Nuestros hallazgos dan cuenta de un proceso de fragmentación y jerarquización del…
Crisis, convivencia multicultural y "efectos de barrio". El caso de dos barrios de Valencia
2015
La inserción urbana de los inmigrantes se desestabiliza y se pone a prueba con la crisis y las políticas aplicadas. Si bien en Valencia se mantiene una convivencia tranquila, la situación de los servicios públicos aumenta la competencia por recursos escasos entre vecinos de diferentes orígenes. Este texto presenta, en el marco de la ciudad de Valencia, un análisis comparativo de dos barrios receptores de inmigrantes que presentan fuertes contrastes. Por un lado, Russafa un barrio céntrico popular y en proceso de gentrification; por otro, Els Orriols, un barrio periférico obrero. Aún con muchos rasgos comunes, la intensidad del recelo hacia el inmigrante varía de un barrio a otro en función …
1914-1918. L'Album della Guerra: regime telescopico e montaggio fotografico della Storia
2014
Negli archivi europei un cercatore di immagini può davvero diventare il pescatore del mare di cui Hannah Arendt parla a proposito di Walter Benjamin collezionista, cioè di Benjamin storico. In breve, di Benjamin filosofo della storia. In particolare, si tratta di sapersi immergere, saper andare al fondo di un patrimonio fotografico enorme che mostra fin dal primo sguardo – e di sguardo si tratterà in modo esteso – una straordinaria accumulazione di immagini di guerra. La relazione tra fotografia e guerra, infatti, è stata sottolineata da molti pensatori e filosofi – e dallo stesso Benjamin –, ma anche da artisti e sperimentatori di tecniche fotografiche del XX secolo, e in particolare, da u…
Añorar el destiempo del 68. Futuros pasados para presentes absortos en España y Francia
2019
Entre la distancia irónica y el gesto doliente, la memoria del definido como “año más histórico de la edad contemporánea” amenaza con verse petrificada tras el retorno a un pasado contemplado como extraño y ajeno a las coordenadas del presente. A diferencia de aquella generación que pensó su futuro como la expectativa de un progreso que dejaba atrás el pretérito del consumo y la burocracia, la nuestra, desafecta con el futuro emancipador de la modernidad y con el presente distópico en el que nos vemos progresivamente sumidos, dirige sus ojos nostálgicos hacia un ayer donde lo posible y deseable han sido devastados por la práctica de lo conocido infranqueable, inclinándonos a miradas retrotó…
Permeability changes of integrin-containing multivesicular structures triggered by picornavirus entry.
2014
Cellular uptake of clustered α2β1-integrin induces the formation of membrane compartments that subsequently mature into a multivesicular body (MVB). Enhanced internalization mediated by clustered integrins was observed upon infection by the picornavirus echovirus 1 (EVI). We elucidated the structural features of virus-induced MVBs (vMVBs) in comparison to antibody-induced control MVBs (mock infection) by means of high-pressure cryo fixation of cells followed by immuno electron tomography during early entry of the virus. Three-dimensional tomograms revealed a marked increase in the size and complexity of these vMVBs and the intraluminal vesicles (ILVs) at 2 and 3.5 hours post infection (p.i.…
Differential expression of Cryptosporidium parvum genes encoding sporozoite surface antigens in infected HCT-8 host cells.
2006
Intracellular replication of Cryptosporidium parvum (Apicomplexa) involves the generation of several asexual and sexual forms of the parasite. During the stage conversions, complex mechanisms lead to differential structural and functional properties of the parasite. These require a well tuned gene transcription machinery. For the first time the gene expression of four surface proteins of C. parvum sporozoites, CP15, CP17, P23, and GP900 were analysed in parallel by reverse transcription polymerase chain reaction. In addition, CP17 and P23 antigens were detected in infected host cells by immunofluorescence using antisera raised against recombinant forms of the proteins. The results show that…