1,103 research outputs found

    Load relief optimization of a first stage boost vehicle using an automated computer design tool

    Get PDF
    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1988.Includes bibliographical references.by Carlos S. Moreno.M.S

    Post-glacial evolution of alpine environments in the western Mediterranean region : The Laguna Seca record

    Get PDF
    In an effort to understand how alpine environments from the western Mediterranean region responded to climate variations since the last glacial-interglacial transition, a detailed chronological control and sedimentological analysis, supported by magnetic susceptibility, total organic carbon and C/N data, were carried out on the sedimentary record of Laguna Seca (LS). This is a latitudinal and altitudinally (2259 masl) key alpine wetland site located in the easternmost area of the Sierra Nevada, southern Iberian Peninsula, where sediments accumulated during Heinrich Stadial 1, Bolling-Allerod (B-A) and the Younger Dryas (YD) previously unrecorded in alpine Sierra Nevada. Climate controlled sedimentation in LS and three coarse-grained and one fine-grained facies association are differentiated, which help us decipher the paleoenvironmental evolution of LS: (1) subaerial cohesionless debris flows during a paraglacial stage; (2) till or nival diamicton during a small glacier/nivation hollow stage; (3) massive mudstone by suspension settling of clays into standing water during a lacustrine stage; and (4) frost-shattering breccia deposited inside the lacustrine stage, probably during the YD, and linked to a periglacial substage. The development of a previously existing small glacial cirque during the Last Glacial Maximum (LGM) in the LS basin at an elevation between 2500 and 2300 m could be supported by the important availability of slope sediments glacially-conditioned such as debris flows, reworked by paraglacial slope processes during the first deglaciation stages, confirming previous studies of landforms in the catchment area and the LGM-Equilibrium Line Altitude estimation above 2400 masl in Sierra Nevada. Mean sediment accumulation rates in the LS sedimentary units (4.21 and 0.28 mm/yr during the paraglacial small glacier/nivation stage and the lacustrine stage, respectively) confirm that geomorphic activity accelerated just after glaciers retreated due to a slope adjustment and high availability of glacially conditioned sediments. An abrupt change in paleoenvironmental and paleoclimatic conditions occurred in LS at ~ 15.7 cal kyr BP. This change was probably due to an increase in temperature and precipitation in the western Mediterranean region during the B-A. At LS, this resulted in significant ice-melt, forming a deep-water lake in LS with important organic matter contribution until the end of the Early Holocene (except in the YD when the lake level probably dropped), but elsewhere a general glacier recession in the Sierra Nevada and an expansion of the Mediterranean forest in the southern Iberian Peninsula. Finally, the general long-term aridification that occurred during the Middle Holocene until the present in the western Mediterranean region triggered an important environmental change transforming LS into an ephemeral wetland with an increase in aquatic productivity.Peer reviewe

    Microtubule stabilization reduces amyloid pathology and improves synaptic/memory deficits in APP/PS1 mice

    Get PDF
    Aims: Cognitive decline in Alzheimer's disease (AD) is highly related to synaptic/neuronal loss. Tau hyperphosphorylation destabilizes microtubules leading to axonal transport failure and generation of dystrophic neurites, thus contributing to synaptic dysfunction. The effect of microtubule stabilization on amyloid-beta pathology has not been assessed in vivo yet. This study evaluated the effect of the microtubule-stabilizing agent, Epothilone D (EpoD) in the pathology of an amyloidogenic mouse model. Methods: APP751SL/PS1M146L mice (3-month-old) were treated weekly with intraperitoneal injections of EpoD (2 mg/kg) or vehicle for 3 months. For memory performance, animals were tested on the objectrecognition, Y-maze and Morris water maze. Hippocampal proteinopathies were quantified by image analysis after immunostaining. Somatostatin (SOM)-numerical density was calculated by stereology. APPswe-N2a cells were treated with EpoD 100nM for 12/24 hours. Protein levels were analysed by Western/dot-blot. Results: EpoD-treated mice improved their performance of cognitive tests, while hippocampal phospho-tau and Ab (especially oligomers) accumulation decreased, together with synaptic/neuritic pathology. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. Conclusions: EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Ab accumulation and promoting neuronal and cognitive protection, underlining the cross-talk between cytoskeleton pathology and proteinopathy. Therefore, microtubule-stabilizing drugs could be candidates for slowing AD at both tau and Ab pathologies.Supported by PI18/01557 (to AG) and PI18/01556 (to JV) grants from ISCiii of Spain, co-financed by FEDER funds (European Union), CIBERNED collaborative grant (to AG and JV), and by PPIT.UMA.B1.2017/26 grant (to RSV). Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Border Integrations: The Fusion of Political Ecology and Land Change Science to Inform and Contest Transboundary Integration in Amazonia

    Get PDF
    In the southwestern Amazon lies the Sierra del Divisor, an isolated cluster of mist-covered peaks and ridges rising out of the steamy lowland rainforest. The forests of these fiercely dissected crests and valleys still ring with the low grunt of jaguar and the thunderous clacks of hundreds-strong herds of whitelipped peccaries, while the canopy sways with troops of the rare red Uakari monkey. This biodiversity inspired the Serra do Divisor National Park, and its transboundary sister reserve, but these forests are also home to humans: the descendants of Asheninka warriors and rubber tappers, a re-emergent Nawa people, I and most elusive, the uncontacted lsconahua. These homelands and ecosystems are crisscrossed with the ephemeral scars made by more recent arrivals: loggers, miners, and drug traffickers. However, the most important line in the Sierra del Divisor is the border itself, the international boundary that follows the Sierra\u27s ridge dividing Peru\u27s Ucayali river basin from Brazil\u27s Jurua basin in the state of Acre. Relatively equidistant from the boundary ridgeline lie rwo cities, Ucayali\u27s capital of Pucallpa, and Western Acre\u27s commercial center, Cruzeiro do Sul. Both cities are the end of the road for their country\u27s nerwork of thoroughfares. For now. Planners and government officials increasingly view the 160 kilometers of forest separating the rwo cities as a temporary obstruction to continental integration. A road connecting the rwo cities would bisect the border and have an impact on flora, fauna, and people. This chapter documents the struggle against this road, a struggle to defend local livelihoods, flora, and fauna from a development initiative pushed at continental, national, and regional scales. In particular, we analyze the synergy of two divergent analytical approaches, land change science (LCS) and political ecology (PE), to gain the best understanding of the impacts of a transboundary road bridging the Brazilian and Peruvian Amazon between the cities of Cruzeiro do Sui and Pucallpa

    LITIO COMO TERAPIA NEUROPROTECTORA EN EL MODELO APPSL/PS1M146L DE LA ENFERMEDAD DE ALZHEIMER

    Get PDF
    El litio se utiliza desde hace varias décadas en el tratamiento de trastornos bipolares y la depresión, y recientemente se debate su uso potencial en patologías neurodegenerativas como la enfermedad de Alzheimer (AD). Diversos estudios han puesto de manifiesto su efecto positivo como potente inhibidor de GSK3beta disminuyendo la fosforilación de tau, la producción de Abeta e incrementando plasticidad sináptica. Sin embargo, su posible efecto neuroprotector previniendo la muerte neuronal in vivo no ha sido aun demostrado ya que la mayoría de los modelos transgénicos de AD no presentan pérdida neuronal. Nuestro modelo APPSL/PS1M146L sufre una pérdida significativa de neuronas SOM/NPY en hipocampo y corteza entorrinal desde edades tempranas (6 meses) con un marcado desarrollo de distrofias axonales. En este trabajo hemos estudiado el posible efecto neuroprotector del litio en este modelo animal mediante tratamiento crónico en la dieta desde los 3 hasta los 9 meses de edad. Se han utilizado técnicas imnunohistoquímicas, western blots y análisis por RT-PCR, y además se ha determinado la carga amiloide, el grado de compactación y el tamaño de las placas. El resultado más relevante de este estudio fue la preservación de la población de interneuronas SOM/NPY tanto en hipocampo como corteza entorrinal en los animales tratados, mientras que en los no tratados existió una pérdida significativa de esta supoblación neuronal. El efecto neuroprotector del litio se manifestó también en una marcada disminución de tau fosforilado, distrofias axonales y marcadores sinápticos, junto con una mejora cognitiva de los animales utilizando el test de reconocimiento de objetos. Este efecto preventivo del litio parece estar asociado con cambios en la formación de placas de Abeta que podrían afectar a su toxicidad, ya que los animales tratados presentaron placas más pequeñas y apariencia más compacta. Financiación: FIS PI12/01431 (AG) y FIS PI12/01439 (JV).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Brucella neotomae Infection in Humans, Costa Rica

    Get PDF
    Several species of Brucella are known to be zoonotic, but B. neotomae infection has been thought to be limited to wood rats. In 2008 and 2011, however, B. neotomae was isolated from cerebrospinal fluid of 2 men with neurobrucellosis. The nonzoonotic status of B. neotomae should be reassessed

    Risks of dengue secondary infective biting associated with aedes aegypti in home environments in Monterrey, Mexico

    Get PDF
    Abstract. Secondary dengue virus infections are a major risk for developing dengue hemorrhagic fever. Recent exposure to infectious bites of Aedes aegypti (L.) females in previously diagnosed dengue cases fulfills the epidemiological model of dengue hemorrhagic fever. A study was comprised of 357 (89.2%) dengue and 43 (10.8%) dengue hemorrhagic fever cases confirmed by laboratory tests and clinical manifestations. An entomological survey was done in homes and backyards. Concurrently, a questionnaire was used to assess the impact of healthpromotion campaigns through knowledge of the vector and its epidemiological role. Seventy-six (28.4%) of the 268 (67.0%) total wet or dry oviposition sites were positive for the presence of larvae or pupae, while adult Ae. aegypti were found in 32 (8.0%). One hundred thirty-two (33%) householders who formerly had dengue fever or dengue hemorrhagic fever had knowledge of either larval or adult dengue vector stages. According to gender distribution, 145 (36.2%) and 14 (3.5%) of the males confirmed with cases of dengue and dengue hemorrhagic fever lived in houses with 17.9 and 2% of the Ae. aegypti larval and pupal habitats. Houses with females who had dengue and dengue hemorrhagic fever were 212 (53%) and 29 (7.3%), with containers with immature Ae. aegypti in 19.4 and 7%, respectively. Lack of sustainability of government-targeted health education campaigns is the major problem for involving communities in prevention and control of dengu

    A polymeric nanomedicine diminishes inflammatory events in renal tubular cells

    Get PDF
    The polyglutamic acid/peptoid 1 (QM56) nanoconjugate inhibits apoptosis by interfering with Apaf-1 binding to procaspase-9. We now describe anti-inflammatory properties of QM56 in mouse kidney and renal cell models. In cultured murine tubular cells, QM56 inhibited the inflammatory response to Tweak, a non-apoptotic stimulus. Tweak induced MCP-1 and Rantes synthesis through JAK2 kinase and NF-kB activation. Similar to JAK2 kinase inhibitors, QM56 inhibited Tweak-induced NF-kB transcriptional activity and chemokine expression, despite failing to inhibit NF-kB-p65 nuclear translocation and NF-kB DNA binding. QM56 prevented JAK2 activation and NF-kB-p65(Ser536) phosphorylation. The anti-inflammatory effect and JAK2 inhibition by QM56 were observed in Apaf-12/2 cells. In murine acute kidney injury, QM56 decreased tubular cell apoptosis and kidney inflammation as measured by downmodulations of MCP-1 and Rantes mRNA expression, immune cell infiltration and activation of the JAK2-dependent inflammatory pathway. In conclusion, QM56 has an anti-inflammatory activity which is independent from its role as inhibitor of Apaf-1 and apoptosis and may have potential therapeutic relevance.This work was supported by grants from the Instituto de Salud Carlos III (www.isciii.es), FIS: PI07/0020, CP08/1083, PS09/00447 and ISCIII-RETICS REDINREN RD 06/0016; Sociedad Española de Nefrología (www.senefro.org). Álvaro Ucero, Sergio Berzal and Carlos Ocaña supported by Fundacion Conchita Rabago (www.fundacionconchitarabago.net), Alberto Ortiz by the Programa de Intensificación de la Actividad Investigadora in the Sistema Nacional de Salud of the Instituto de Salud Carlos III and the Agencia ‘‘Pedro Lain Entralgo’’ of the Comunidad de Madrid and CIFRA S-BIO 0283/2006 www.madrid.org/lainentralgo) and Adrián Ramos, by FIS (Programa Miguel Servet)
    corecore