1,981 research outputs found

    Leafing patterns and drivers across seasonally dry tropical communities

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    Investigating the timing of key phenological events across environments with variable seasonality is crucial to understand the drivers of ecosystem dynamics. Leaf production in the tropics is mainly constrained by water and light availability. Identifying the factors regulating leaf phenology patterns allows efficiently forecasting of climate change impacts. We conducted a novel phenological monitoring study across four Neotropical vegetation sites using leaf phenology time series obtained from digital repeated photographs (phenocameras). Seasonality differed among sites, from very seasonally dry climate in the caatinga dry scrubland with an eight-month long dry season to the less restrictive Cerrado vegetation with a six-month dry season. To unravel the main drivers of leaf phenology and understand how they influence seasonal dynamics (represented by the green color channel (Gcc) vegetation index), we applied Generalized Additive Mixed Models (GAMMs) to estimate the growing seasons, using water deficit and day length as covariates. Our results indicated that plant-water relationships are more important in the caatinga, while light (measured as day-length) was more relevant in explaining leafing patterns in Cerrado communities. Leafing behaviors and predictor-response relationships (distinct smooth functions) were more variable at the less seasonal Cerrado sites, suggesting that different life-forms (grasses, herbs, shrubs, and trees) are capable of overcoming drought through specific phenological strategies and associated functional traits, such as deep root systems in trees

    Species pool structure determines the level of generalism of island parasitoid faunas

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    Copyright © 2011 Blackwell Publishing Ltd.AIM To examine whether island parasitoid faunas are biased towards generalists when compared with the mainland and their species pool, and to evaluate the effects of climate, island characteristics and regional factors on the relative proportions of idiobionts (i.e. generalists) and koinobionts (i.e. specialists) of two parasitic wasp families, Braconidae and Ichneumonidae. LOCATION Seventy-three archipelagos distributed world-wide. METHODS We used data on the distribution and biology obtained from a digital catalogue and several literature sources. We related level of generalism, measured as the ratio between the number of idiobiont and koinobiont species, to climatic, physiographic and regional factors using generalized linear models. We compared models by means of Akaike weighting, and evaluated the spatial structure of their residuals. We used partial regressions to determine whether the final models account for all latitudinal structure in the level of generalism. RESULTS Islands host comparatively more idiobionts than continental areas. Although there is a latitudinal gradient in the level of generalism of island faunas correlating with both environmental factors and island characteristics, the most important determinant of island community structure is their source pool. This effect is stronger for ichneumonids, where generalism is higher in the Indomalayan region, arguably due to the higher diversity of endophytic hosts in its large rain forests. MAIN CONCLUSIONS The level of generalism of island parasitoid faunas is largely constrained by regional factors, namely by the structure of the species pool, which emphasizes the importance of including regional processes in our understanding of the functioning of ecological communities. The fact that generalist species are more predominant in islands with a large cover of rain forests pinpoints the importance of the indirect effects of ecological requirements on community structure, highlighting the complex nature of geographical gradients of diversity

    Applications of natural, semi-synthetic, and synthetic polymers in cosmetic formulations

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    Cosmetics composed of synthetic and/or semi-synthetic polymers, associated or not with natural polymers, exhibit a dashing design, with thermal and chemo-sensitive properties. Cosmetic polymers are also used for the preparation of nanoparticles for the delivery of, e.g., fragrances, with the purpose to modify their release profile and also reducing the risk of evaporation. Besides, other cosmetically active nutrients, dermal permeation enhancers, have also been loaded into nanoparticles to improve their bioactivities on the skin. The use of natural polymers in cosmetic formulations is of particular relevance because of their biocompatible, safe, and eco-friendly character. These formulations are highly attractive and marketable to consumers, and are suitable for a plethora of applications, including make-up, skin, and hair care, and as modifiers and stabilizers. In this review, natural synthetic, semi-synthetic, and synthetic polymers are discussed considering their properties for cosmetic applications. Their uses in conventional and novel formulations are also presented.This research was funded by Banco do Nordeste (FUNDECI 2017.0016), Coordenação Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Amparo à Pesquisa do Estado de Sergipe (FAPITEC)(PROCESSO: 88887.159533/2017-00), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq301964/2019-0, and Chamada CNPq nº01/2019) and by Portuguese Science and Technology Foundation, Ministryof Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the project reference UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020info:eu-repo/semantics/publishedVersio

    Factors associated with thrombocytopenia in severe leptospirosis (Weil's disease)

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    OBJECTIVE: This study was conducted to investigate factors associated with thrombocytopenia in a large cohort of patients with leptospirosis in an endemic area. METHODS: This retrospective study included 374 consecutive patients with leptospirosis who were admitted to tertiary hospitals in Fortaleza, Brazil. All patients had a diagnosis of severe leptospirosis (Weil's disease). Acute kidney injury was defined according to the RIFLE criteria. Thrombocytopenia was defined as a platelet coun

    Lipid-polymeric films: composition, production and applications in wound healing and skin repair

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    The use of lipids in the composition of polymeric-based films for topical administration of bioactive ingredients is a recent research topic; while few products are commercially available, films containing lipids represent a strategic area for the development of new products. Some lipids are usually used in polymeric-based film formulations due to their plasticizing action, with a view to improving the mechanical properties of these films. On the other hand, many lipids have healing, antimicrobial, anti-inflammatory, anti-aging properties, among others, that make them even more interesting for application in the medical-pharmaceutical field. This manuscript discusses the production methods of these films both on a laboratory and at industrial scales, the properties of the developed biopolymers, and their advantages for the development of dermatologic and cosmetic products.This research was funded by the Portuguese Science and Technology Foundation (FCT/MCT) and European Funds (PRODER/COMPETE), under the project reference UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

    Discovery of the Anticancer Activity for Lung and Gastric Cancer of a Brominated Coelenteramine Analog

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    Supplementary Materials: The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/ijms23158271/s1.Cancer is still a challenging disease to treat, both in terms of harmful side effects and therapeutic efficiency of the available treatments. Herein, to develop new therapeutic molecules, we have investigated the anticancer activity of halogenated derivatives of different components of the bioluminescent system of marine Coelenterazine: Coelenterazine (Clz) itself, Coelenteramide (Clmd), and Coelenteramine (Clm). We have found that Clz derivatives possess variable anticancer activity toward gastric and lung cancer. Interestingly, we also found that both brominated Clmd (Br-Clmd) and Clm (Br-Clm) were the most potent anticancer compounds toward these cell lines, with this being the first report of the anticancer potential of these types of molecules. Interestingly, Br-Clm possessed some safety profile towards noncancer cells. Further evaluation revealed that the latter compound induced cell death via apoptosis, with evidence for crosstalk between intrinsic and extrinsic pathways. Finally, a thorough exploration of the chemical space of the studied Br-Clm helped identify the structural features responsible for its observed anticancer activity. In conclusion, a new type of compounds with anticancer activity toward gastric and lung cancer was reported and characterized, which showed interesting properties to be considered as a starting point for future optimizations towards obtaining suitable chemotherapeutic agents.The Portuguese “Fundação para a Ciência e Tecnologia“ (FCT) is acknowledged for funding project PTDC/QUI-QFI/2870/2020, the R&D Units CIQUP (UIDB/00081/2020), GreenUPorto (UIDB/05748/2020), LAQV/REQUIMTE (UIDB/50006/2020), and the Associated Laboratory IMS (LA/P/0056/2020). L. Pinto da Silva acknowledges funding from FCT under the Scientific Employ ment Stimulus (2021.00768.CEECIND). Patricia González-Berdullas acknowledges funding for her postdoctoral position in the framework of project PTDC/QUI/QFI/2870/2020. Carla Magalhães acknowledges FCT for her PhD grant (SRFH/BD/143211/2019). Renato B. Pereira acknowledges PRIMA Foundation (H2020- PRIMA 2018—Section 2, Project MILKQUA) and FCT (PTDC/QUI QFI/2870/2020) for the funding

    Enhanced dissolution efficiency of tamoxifen combined with methacrylate copolymers in amorphous solid dispersions

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    Amorphous solid dispersions (SDs) containing poorly soluble tamoxifen dispersed in a meth(acrylate) copolymer combination were proposed as a controlled release system. The objective of this work was to investigate the characteristics and performance of the tamoxifen–polymer mixture and evaluate the changes in functionality through a supersaturating dissolution study condition while comparing it to a physical mixture at a fixed drug-loading proportion. Two polymers, Eudragit® L 100 and Eudragit® RL 100, were used to prepare SDs with a 1:1 polymer ratio, containing 10%, 20%, or 30% (wt/wt%) of tamoxifen, by the solvent evaporation method. A physical mixture containing 30% of tamoxifen was also prepared for comparison. SDs were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Dissolution tests were conducted under non-sink conditions to verify the occurrence of drug recrystallization upon its release. Solid-state characterizations confirmed that the drug was in the amorphous state within the polymeric matrix. Tamoxifen release in an acidic medium was mainly affected by the increase in drug concentration caused by the possible loss of interactions that characterize the main polymer functionalities. At pH 7.4, supersaturation was slowly achieved while also contributing to the increase in the kinetic solubility of the drug. The physical mixture demonstrated the best overall performance, suggesting that the polymeric interactions may have negatively affected the drug release. The combination of polymers in the composing SD proved to be a promising strategy to tailor the delivery of poorly soluble drugs. Our study highlights important information on the behavior of tamoxifen as a poorly soluble drug in supersaturating dissolution conditions while released from SD systems.This work was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil), by the Portuguese Science and Technology Foundation (FCT/MCT), and European Funds (PRODER/COMPETE) under the projects M-ERA-NET/0004/2015 and UIDB/04469/2020 (strategic fund) and co-financed by FEDER under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio
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