36 research outputs found

    Factors influencing terrestriality in primates of the Americas and Madagascar

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    Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use

    Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

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    Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

    High Current Density in c-Si PECVD Diodes for Low Temperature

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    The development of microcrystalline diodes grown at low temperature by PECVD techniques is reported. Current densities near 200 A/cm at + 2 V, and rectification ratios on the order of 10 at +/- 2V were obtained. The reverse currents were in the nanoampere range. Correlations between deposition cond itions and film quality are presented. The effects of mesa formation and subsequent treatments designed to reduce process damage are discussed: annealing conditions yield an increase in forward current, and a decrease in reverse current. Fabrication cond itions are compatible with applications requiring low temperature processes (e. g., multi- layer structures, molecular layers, or plastic substrates and coatings)

    The morphological and molecular features of the epithelial-to-mesenchymal transition

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    peer reviewedHere we describe several methods for the characterization of epithelial–mesenchymal transition (EMT) at the cellular, molecular and behavioral level. This protocol describes both in vitro and in vivo approaches designed to analyze different features that when taken together permit the characterization of cells undergoing transient or stable EMT. We define straightforward methods for phenotypical, cellular and transcriptional characterization of EMT in vitro in monolayer cultures. The procedure also presents technical details for the generation of in vitro three-dimensional (3D) cultures analyzing cell phenotype and behavior during the EMT process. In addition, we describe xenotransplantation techniques to graft 3D cell cultures into mice to study in vivo invasion in a physiological-like environment. Finally, the protocol describes the analysis of selected EMT markers from experimental and human tumor samples. This series of methods can be applied to the study of EMT under various experimental and biological situations. Once the methodology is established, the time required to complete the protocol may vary from 3 to 4 weeks (monolayer cultures) and up to 6–8 weeks if including 3D cultures

    Regulation of Distinct Septin Rings in a Single Cell by Elm1p and Gin4p Kinases

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    Septins are conserved, GTP-binding proteins that assemble into higher order structures, including filaments and rings with varied cellular functions. Using four-dimensional quantitative fluorescence microscopy of Ashbya gossypii fungal cells, we show that septins can assemble into morphologically distinct classes of rings that vary in dimensions, intensities, and positions within a single cell. Notably, these different classes coexist and persist for extended times, similar in appearance and behavior to septins in mammalian neurons and cultured cells. We demonstrate that new septin proteins can add through time to assembled rings, indicating that septins may continue to polymerize during ring maturation. Different classes of rings do not arise from the presence or absence of specific septin subunits and ring maintenance does not require the actin and microtubule cytoskeletons. Instead, morphological and behavioral differences in the rings require the Elm1p and Gin4p kinases. This work demonstrates that distinct higher order septin structures form within one cell because of the action of specific kinases

    Trypanosoma cruzi, cancer and the Cold War Trypanosoma cruzi, câncer e a Guerra Fria

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    In the summer of 1946, the international community of cancer researchers was inspired by the announcement that two Soviet scientists, Nina Kliueva and Grigorii Roskin, had discovered anticancer properties in culture extracts made from the South American protozoan, Trypanosoma cruzi, and had produced a preparation - named after its discoverers KR - which showed clear therapeutic effects on cancer patients. Research teams from various countries enthusiastically pursued the promising new line of investigation. The story of the rise and fall of interest in the anticancer properties of T. cruzi in different countries suggests that during the second half of the twentieth century, the Cold War competition between the superpowers played an important role in shaping the research agendas of cancer studies.<br>No verão de 1946, a comunidade internacional que desenvolve pesquisas sobre o câncer, inspirou-se no anúncio de que dois cientistas soviéticos, Nina Kliueva e Grigorii Roskin, descobriram propriedades anticancerígenas em cultura extraída do protozoário existente na América Latina, o Trypanosoma cruzi e produziram um preparado que foi denominado com as iniciais KR - em sua homenagem. Grupos de pesquisadores de diversos países buscaram com entusiasmo as promessas dessa nova linha de investigação. A história da ascensão e queda do interesse nas propriedades anticâncer do T. cruzzi em diferentes países sugere que durante a segunda metade do século 20, a Guerra Fria teve um papel importante na definição das agendas de pesquisas sobre o câncer
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