2,581 research outputs found
Nanoparticle drug delivery systems for inner ear therapy: An overview
open7noembargoed_20180701Valente, Filippo; Astolfi, Laura; Simoni, Edi; Danti, Serena; Franceschini, Valeria; Chicca, Milvia; Martini, AlessandroValente, Filippo; Astolfi, Laura; Simoni, Edi; Danti, Serena; Franceschini, Valeria; Chicca, Milvia; Martini, Alessandr
A High Power Solar Electric Propulsion - Chemical Mission for Human Exploration of Mars
Recently Solar Electric Propulsion (SEP) as a main propulsion system has been investigated as an option to support manned space missions to near-Earth destinations for the NASA Gateway spacecraft. High efficiency SEP systems are able to reduce the amount of propellant long duration chemical missions require, ultimately reducing the required mass delivered to Low Earth Orbit (LEO) by a launch vehicle. However, for long duration interplanetary Mars missions, using SEP as the sole propulsion source alone may not be feasible due to the long trip times to reach and insert into the destination orbit. By combining an SEP propulsion system with a chemical propulsion system the mission is able to utilize the high-efficiency SEP for sustained vehicle acceleration and deceleration in heliocentric space and the chemical system for orbit insertion maneuvers and trans-earth injection, eliminating the need for long duration spirals. By capturing chemically instead of with low-thrust SEP, Mars stay time increases by nearly 200 days. Additionally, the size the of chemical propulsion system can be significantly reduced from that of a standard Mars mission because the SEP system greatly decreases the Mars arrival and departure hyperbolic excess velocities (V(sub infinity))
Evolution and architecture of a West Mediterranean upper Pleistocene to Holocene coastal apron-fan system
The Quaternary deposits of tectonically stable areas are a powerful tool to investigate high-frequency climate variations (<10 ka) and to distinguish allogenic and autogenic factors controlling deposition. Therefore, an Upper Pleistocene—Holocene coastal apron-fan system in north—western Sardinia (Porto Palmas, Italy) was studied to investigate the relations between climate changes, sea-level fluctuations and sediment source-supply that controlled its development. The sedimentary sequence records the strong influence of local (wet/dry) and worldwide (sea-level) environmental variations in the sedimentation and preservation of the deposits. A multi-disciplinary approach allowed subdivision of the succession into four major, unconformity-bounded stratigraphic units: U1 U2, U3 and U4. Unit U1, tentatively dated to the warm and humid Marine Isotopic Stage (MIS) 5, consists of sandy, gravelly coastal/beach deposits developed during high sea-level in low-lying areas. Unit U2 consists of debris-flow dominated fan-deposits (ca 74 ka; MIS 4), preserved as partial fills of small valleys and coves. Unit U2 is mainly composed of reddish silty conglomerate to pebbly siltstones sourced from the Palaeozoic metamorphic inland hills (bedrock), superficially disintegrated during the preceding warm, vegetation-rich MIS 5. The cold and semi-arid climate strongly reduced vegetation cover along the valley flanks. Therefore, sediment gravity-flow processes, possibly activated by rainstorms, led to deposition of debris-flow dominated fans. Unit U3 consists of water-flow dominated alluvial-fan deposits (ca 47 to 23 ka; MIS 3), developed on a slightly inclined coastal plain. Unit U3 is composed of sandstone and sandy conglomerate fed from two main sediment sources: metamorphic inland bedrock and Quaternary bioclastic-rich shelf-derived sands. During this cold phase, sea-level dropped sufficiently to expose bioclastic sands accumulated on the shelf. Frequent climate fluctuations favoured inland aeolian transport of sand during dry phases, followed by reworking of the aeolian bodies by flash floods during wet phases. Bedrock-derived fragments mixed with water-reworked, wind-blown sands led to the development of water-flow dominated fans. The Dansgaard—Oeschger events possibly associated with sand landward deflation and main fan formations are Dansgaard—Oeschger 13 (ca 47 ka), Dansgaard—Oeschger 8 (ca 39 ka) and Dansgaard—Oeschger 2 (ca 23 ka). No record of sedimentation during MIS 2 was observed. Finally, bioclastic-rich aeolianites (Unit U4, ca 10 to 5 ka; MIS 1), preserved on a coastal slope, were developed during the Holocene transgression (ca 10 to 5 ka; MIS 1). The studied sequence shows strong similarities with those of other Mediterranean sites; it is, however, one of the few where the main MIS 4 and MIS 3 climatic fluctuations are registered in the sedimentary record
Propuesta metodológica para la adaptación del Parque Residencial construido a las condiciones energéticas y de habitabilidad según Ley 13.059, Prov. de Buenos Aires
El trabajo presenta una metodología para el análisis y evaluación de las calidades térmicas y las condiciones de habitabilidad de la edilicia residencial existente en abordaje masivo, considerando como condición base los requerimientos de la ley 13059 de la Prov. de Buenos Aires. A través de este estudio se exponen conclusiones que buscan fundamentar la incorporación de la eficiencia energética al parque construido, como complemento a dicha Ley que sólo afecta a las construcciones nuevas. Para ello se describe la metodología de clasificación y evaluación de la edilicia residencial existente. Se presenta un ejemplo de aplicación sobre una tipología representativa, la cual es reproducida en un universo mayor. Con ello se concluye que la aplicación de las condiciones exigidas por la Ley 13059 en la edilicia existente aseguraría beneficios tanto para cada individuo como para el colectivo y el Estado, siendo el gobierno el promotor idóneo para un plan de reciclado masivo.Fil: Rodríguez, Lucas Gastón. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Salta. Instituto de Invest.en Energia No Convencional. Grupo Vinculado Al Inenco - Instituto de Inv. y Politicas l;Fil: Garganta, Maria Laura. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Salta. Instituto de Invest.en Energia No Convencional. Grupo Vinculado Al Inenco - Instituto de Inv. y Politicas del;Fil: Martini, Irene. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Salta. Instituto de Invest.en Energia No Convencional. Grupo Vinculado Al Inenco - Instituto de Inv. y Politicas del;Fil: San Juan, Gustavo Alberto. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Salta. Instituto de Invest.en Energia No Convencional. Grupo Vinculado Al Inenco - Instituto de Inv. y Politicas del;Fil: Discoli, Carlos Alberto. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Salta. Instituto de Invest.en Energia No Convencional. Grupo Vinculado Al Inenco - Instituto de Inv. y Politicas del
Predictors of mother–child interaction quality and child attachment security in at-risk families
Child healthy development is largely influenced by parent-child interaction and a secure parent-child attachment is predictively associated with positive outcomes in numerous domains of child development. However, the parent-child relationship can be affected by several psychosocial and socio-demographic risk factors that undermine its quality and in turn play a negative role in short and long term child psychological health. Prevention and intervention programs that support parenting skills in at-risk families can efficiently reduce the impact of risk factors on mother and child psychological health. This study examines predictors of mother-child interaction quality and child attachment security in a sample of first-time mothers with psychosocial and/or socio-demographic risk factors. Forty primiparous women satisfying specific risk criteria participated in a longitudinal study with their children from pregnancy until 18 month of child age. A multiple psychological and socioeconomic assessment was performed. The Emotional Availability Scales were used to measure the quality of emotional exchanges between mother and child at 12 months and the Attachment Q-Sort served as a measure of child attachment security at 18 months. Results highlight both the effect of specific single factors, considered at a continuous level, and the cumulative risk effect of different co-occurring factors, considered at binary level, on mother-child interaction quality and child attachment security. Implication for the selection of inclusion criteria of intervention programs that support parenting skills in at-risk families are discussed
Localization and subcellular association of Grapevine Pinot Gris Virus in grapevine leaf tissues
Despite the increasing impact of Grapevine Pinot gris disease (GPG-disease) worldwide, etiology about this disorder is still uncertain. The presence of the putative causal agent, the Grapevine Pinot Gris Virus (GPGV), has been reported in symptomatic grapevines (presenting stunting, chlorotic mottling, and leaf deformation) as well as in symptom-free plants. Moreover, information on virus localization in grapevine tissues and virus-plant interactions at the cytological level is missing at all. Ultrastructural and cytochemical investigations were undertaken to detect virus particles and the associated cytopathic effects in field-grown grapevine showing different symptom severity. Asymptomatic greenhouse-grown grapevines, which tested negative for GPGV by real time RT-PCR, were sampled as controls. Multiplex real-time RT-PCR and ELISA tests excluded the presence of viruses included in the Italian certification program both in field-grown and greenhouse-grown grapevines. Conversely, evidence was found for ubiquitous presence of Grapevine Rupestris Stem Pitting-associated Virus (GRSPaV), Hop Stunt Viroid (HSVd), and Grapevine Yellow Speckle Viroid 1 (GYSVd-1) in both plant groups. Moreover, in every field-grown grapevine, GPGV was detected by real-time RT-PCR. Ultrastructural observations and immunogold labelling assays showed filamentous flexuous viruses in the bundle sheath cells, often located inside membrane-bound organelles. No cytological differences were observed among field-grown grapevine samples showing different symptom severity. GPGV localization and associated ultrastructural modifications are reported and discussed, in the perspective of assisting management and control of the disease. \ua9 2017 The Author(s
Filamentous sieve element proteins are able to limit phloem mass flow, but not phytoplasma spread
In Fabaceae, dispersion of forisomes\u2014highly ordered aggregates of sieve element proteins\u2014in response to phytoplasma infection was proposed to limit phloem mass flow and, hence, prevent pathogen spread. In this study, the involvement of filamentous sieve element proteins in the containment of phytoplasmas was investigated in non-Fabaceae plants. Healthy and infected Arabidopsis plants lacking one or two genes related to sieve element filament formation\u2014AtSEOR1 (At3g01680), AtSEOR2 (At3g01670), and AtPP2-A1 (At4g19840)\u2014were analysed. TEM images revealed that phytoplasma infection induces phloem protein filament formation in both the wild-type and mutant lines. This result suggests that, in contrast to previous hypotheses, sieve element filaments can be produced independently of AtSEOR1 and AtSEOR2 genes. Filament presence was accompanied by a compensatory overexpression of sieve element protein genes in infected mutant lines in comparison with wild-type lines. No correlation was found between phloem mass flow limitation and phytoplasma titre, which suggests that sieve element proteins are involved in defence mechanisms other than mechanical limitation of the pathogen
- …
