1,089 research outputs found

    Odysseus' "Winnowing-Shovel" (Horn. Od. 11. 119-37) and the Island of the Cattle of the Sun

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    El crimen de los oligarcas corcirenses (Th. III 70.4)

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    At Th. 3.70.4, a number of Corcyraean oligarchs are convicted of illegally ‘cutting stakes’ (τέμνειν χάρακας) in two local sanctuaries. The significance of this charge is disputed among commentators. We offer detailed support of Hornblower’s conclusion that the Corcyraean oligarchs are charged with cutting saplings from sacred land for use as vine-stakes in their own fields. Our argument places Thucydides’ account of events in a larger philological, ecological and social framework, and suggests that the details of the accusation help establish abuse of communally controlled natural resources and the court system as prodromal stages in the social deterioration that ultimately produces the stasis on Corcyra and by implication elsewhere as well.En Th. III 70.4 se acusa a un grupo de oligarcas de Corcira por ‘cortar estacas’ (τέμνειν χάρακας) ilegalmente en dos santuarios locales. Los comentaristas discuten el significado de esta acusación. Ofrecemos apoyo detallado a la conclusión de Hornblower, según la cual se acusa a los oligarcas corcirenses de cortar árboles jóvenes de terreno sagrado para usarlos como puntales de viñas en sus campos privados. Nuestro argumento sitúa el relato de Tucídides en un marco filológico, ecológico y social más amplio, y sugiere que los detalles de la acusación ayudan a establecer el abuso de recursos naturales controlados por la comunidad y el sistema judicial como fases preliminares en el deterioro social que terminó produciendo la stasis en Corcira e implícitamente también en otros lugares

    Notas filológicas sobre la letra alfa en un nuevo diccionario etimológico del griego, con especial atención al material de Hesiquio

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    Hasta hace poco, los dos diccionarios etimológicos griegos estándar eran Frisk 1960 y Chantraine 1968 (segunda edición: 1999, tercera edición: 2009), si bien Frisk no estaba en condiciones de tomar en consideración la evidencia del Lineal B, y ninguno de ellos tuvo en cuenta la teoría laringal. Por el contrario, las laringales son fundamentales para muchas entradas en Beekes 2010, que se ha convertido en una herramienta de investigación fundamental en el campo de los estudios clásicos. Las notas filológicas detalladas que se ofrecen aquí se centran en cambio en el manejo de Beekes de la lengua griega en sí, con especial atención al material extraído de Hesiquio. El argumento implícito es que el manejo del griego en el nuevo diccionario es a menudo poco fiable, y que los lectores deben tomar su manejo de los textos antiguos, en particular los lexicógrafos, y por lo tanto muchas de sus conclusiones individuales, con precaución

    Some overlooked Athenian economic vocabulary (ἀγοραί and λιμένες)

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    Comparison of passages in Aristophanes, Xenophon and Demosthenes suggests that ἀγοραί (literally “marketplaces”) and λιμένες (literally “harbors”) should be recognized as 5th- and 4th-century Athenian idioms referring to state revenues generated by the sale of the right to collect taxes from such sources

    Proteomic analysis of tomato (Lycopersicon esculentum) pollen

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    In flowering plants, pollen grains are produced in the anther and released to the external environment with the primary function of delivering sperm cells to the female gametophyte. This study was conducted to identify proteins in tomato pollen and to analyse their roles in relation to pollen function. Tomato is an important crop which is grown worldwide and is an excellent experimental system. Proteins were extracted from pollen, separated by two-dimensional gel electrophoresis (2-DE), and identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and peptide mass fingerprinting. Of the 960 spots observed on Colloidal Coomassie Blue (CCB)-stained 2-DE gels, 190 were selected for analysis. Of these, 158 spots, representing 133 distinct proteins, were identified by searching the NCBInr and Expressed Sequence Tag databases. The identified proteins were classified based on designated functions and the majority included those involved in defence mechanisms, energy conversions, protein synthesis and processing, cytoskeleton formation, Ca(2+) signalling, and as allergens. A number of proteins in tomato pollen were similar to those reported in the pollen of other species; however, several additional proteins with roles in defence mechanisms, metabolic processes, and hormone signalling were identified. The potential roles of the identified proteins in the survival strategy of the small, independent, two-celled pollen grain of tomato, and subsequently in pollen germination and tube growth are discussed

    Proteome profile and functional classification of proteins in Arabidopsis thaliana (Landsberg erecta) mature pollen

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    Proteome analysis of mature Arabidopsis thaliana (Landsberg erecta ecotype) pollen was conducted using two-dimensional gel electrophoresis and mass spectrometry. A total of 960 spots were resolved on pH 4–7 IPG strips and 110 distinct proteins were identified from 150 spots analyzed. The identified proteins were categorized based on their functional role in the pollen, which included proteins involved in energy regulation, defense-related mechanisms, calcium-binding and signaling, cytoskeletal formation, pollen allergens, glycine-rich proteins (GRPs), and late embryogenesis abundant (LEA) proteins. These proteins potentially play important roles in pollen function at maturity and during subsequent germination and tube growth. Some of the proteins identified were related to known pollen-specific transcripts, while some were similar to proteins found in the seed. In this study, 66 new proteins were identified which were not reported in two other recent studies on Arabidopsis pollen, 17 proteins were common in all three studies, and 35 or 26 proteins reported here had an overlap with one or the other two studies. These differences may be attributed to the methods of protein extraction, spot selection for analysis, and the ecotype used. Together, the three studies provide a broad spectrum of the Arabidopsis pollen proteome

    Electron Tomography of HIV-1 Infection in Gut-Associated Lymphoid Tissue

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    Critical aspects of HIV-1 infection occur in mucosal tissues, particularly in the gut, which contains large numbers of HIV-1 target cells that are depleted early in infection. We used electron tomography (ET) to image HIV-1 in gut-associated lymphoid tissue (GALT) of HIV-1–infected humanized mice, the first three-dimensional ultrastructural examination of HIV-1 infection in vivo. Human immune cells were successfully engrafted in the mice, and following infection with HIV-1, human T cells were reduced in GALT. Virions were found by ET at all stages of egress, including budding immature virions and free mature and immature viruses. Immuno-electron microscopy verified the virions were HIV-1 and showed CD4 sequestration in the endoplasmic reticulum of infected cells. Observation of HIV-1 in infected GALT tissue revealed that most HIV-1–infected cells, identified by immunolabeling and/or the presence of budding virions, were localized to intestinal crypts with pools of free virions concentrated in spaces between cells. Fewer infected cells were found in mucosal regions and the lamina propria. The preservation quality of reconstructed tissue volumes allowed details of budding virions, including structures interpreted as host-encoded scission machinery, to be resolved. Although HIV-1 virions released from infected cultured cells have been described as exclusively mature, we found pools of both immature and mature free virions within infected tissue. The pools could be classified as containing either mostly mature or mostly immature particles, and analyses of their proximities to the cell of origin supported a model of semi-synchronous waves of virion release. In addition to HIV-1 transmission by pools of free virus, we found evidence of transmission via virological synapses. Three-dimensional EM imaging of an active infection within tissue revealed important differences between cultured cell and tissue infection models and furthered the ultrastructural understanding of HIV-1 transmission within lymphoid tissue

    Circumferential Vascular Deformation after Stent Implantation Alters Wall Shear Stress Evaluated with Time-Dependent 3D Computational Fluid Dynamics Models

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    The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD) models suggest that stent geometry may cause local alterations in wall shear stress (WSS) that have been associated with neointimal hyperplasia and subsequent restenosis. However, previous CFD studies have ignored histological evidence of vascular straightening between circumferential stent struts. We tested the hypothesis that consideration of stent-induced vascular deformation may more accurately predict alterations in indexes of WSS that may subsequently account for histological findings after stenting. We further tested the hypothesis that the severity of these alterations in WSS varies with the degree of vascular deformation after implantation. Steady-state and time-dependent simulations of three-dimensional CFD arteries based on canine coronary artery measurements of diameter and blood flow were conducted, and WSS and WSS gradients were calculated. Circumferential straightening introduced areas of high WSS between stent struts that were absent in stented vessels of circular cross section. The area of vessel exposed to low WSS was dependent on the degree of circumferential vascular deformation and axial location within the stent. Stents with four vs. eight struts increased the intrastrut area of low WSS in vessels, regardless of cross-sectional geometry. Elevated WSS gradients were also observed between struts in vessels with polygonal cross sections. The results obtained using three-dimensional CFD models suggest that changes in vascular geometry after stent implantation are important determinants of WSS distributions that may be associated with subsequent neointimal hyperplasia

    Stent Design Properties and Deployment Ratio Influence Indexes of Wall Shear Stress: a Three-Dimensional Computational Fluid Dynamics Investigation within a Normal Artery

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    Restenosis limits the effectiveness of stents, but the mechanisms responsible for this phenomenon remain incompletely described. Stent geometry and expansion during deployment produce alterations in vascular anatomy that may adversely affect wall shear stress (WSS) and correlate with neointimal hyperplasia. These considerations have been neglected in previous computational fluid dynamics models of stent hemodynamics. Thus we tested the hypothesis that deployment diameter and stent strut properties (e.g., number, width, and thickness) influence indexes of WSS predicted with three-dimensional computational fluid dynamics. Simulations were based on canine coronary artery diameter measurements. Stent-to-artery ratios of 1.1 or 1.2:1 were modeled, and computational vessels containing four or eight struts of two widths (0.197 or 0.329 mm) and two thicknesses (0.096 or 0.056 mm) subjected to an inlet velocity of 0.105 m/s were examined. WSS and spatial WSS gradients were calculated and expressed as a percentage of the stent and vessel area. Reducing strut thickness caused regions subjected to low WSS (/cm2) to decrease by ∼87%. Increasing the number of struts produced a 2.75-fold increase in exposure to low WSS. Reducing strut width also caused a modest increase in the area of the vessel experiencing low WSS. Use of a 1.2:1 deployment ratio increased exposure to low WSS by 12-fold compared with stents implanted in a 1.1:1 stent-to-vessel ratio. Thinner struts caused a modest reduction in the area of the vessel subjected to elevated WSS gradients, but values were similar for the other simulations. The results suggest that stent designs that reduce strut number and thickness are less likely to subject the vessel to distributions of WSS associated with neointimal hyperplasia

    Reactive Oxygen Species Modulate Coronary Wall Shear Stress and Endothelial Function During Hyperglycemia

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    Hyperglycemia is associated with generation of reactive oxygen species (ROS), and this action may contribute to accelerated atherogenesis. We tested the hypothesis that hyperglycemia produces alterations in left anterior descending coronary artery (LAD) wall shear stress concomitant with endothelial dysfunction and ROS production in dogs (n = 12) instrumented for measurement of LAD blood flow, velocity, and diameter. Dogs were randomly assigned to receive vehicle (0.9% saline) or the superoxide dismutase mimetic 4- hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (tempol) and were administered intravenous infusions of d-glucose to achieve target blood glucose concentrations of 350 and 600 mg/dl (moderate and severe hyperglycemia, respectively). Endothelial function and ROS generation were assessed by coronary blood flow responses to acetylcholine (10, 30, and 100 ng/kg) and dihydroethidium fluorescence of myocardial biopsies, respectively. Indexes of wall shear stress were calculated with conventional fluid dynamics theory. Hyperglycemia produced dose-related endothelial dysfunction, increases in ROS production, and reductions in oscillatory shear stress that were normalized by tempol. The results suggest a direct association between hyperglycemia-induced ROS production, endothelial dysfunction, and decreases in oscillatory shear stress in vivo
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