2,221 research outputs found

    A multi-metal risk assessment strategy for natural freshwater ecosystems based on the additive inhibitory free metal ion concentration index

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    Scientifically sound risk assessment strategies and derivations of environmental quality standards for metals present in freshwater environments are currently hampered by insufficient chronic toxicity data collected from natural ecosystems, as well as inadequate information on metal speciation. Thus, the aim of the present study was to evaluate the impact of freshwater containing multiple metals (Cd, Cr, Cu, Ni, Pb and Zn) on the chronic toxicity (72h) to the alga Pseudokirchneriella subcapitata and compare the observed toxicity results to the total and free metal concentration of the samples. Based on the information obtained herein, an additive inhibitory free multi-metal ion concentration index, calculated as the sum of the equivalent toxicities to the free metal ion concentration of each sample, was developed. The proposed index was well correlated to the observed chronic toxicity results, indicating that the concentration addition, when expressed as the free-ion activity, can be considered a reliable indicator for the evaluation of ecological risk assessments for natural waters containing multiple metals.This work was performed in the framework of the financing with references LAQV (UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265) and UID/BIO/04469/2013 - POCI-01-0145-FEDER-006684 with financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 and Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)

    Experimental Models as Refined Translational Tools for Breast Cancer Research

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    Breast cancer is one of the most common cancers worldwide, which makes it a very impactful malignancy in the society. Breast cancers can be classified through different systems based on the main tumor features and gene, protein, and cell receptors expression, which will determine the most advisable therapeutic course and expected outcomes. Multiple therapeutic options have already been proposed and implemented for breast cancer treatment. Nonetheless, their use and efficacy still greatly depend on the tumor classification, and treatments are commonly associated with invasiveness, pain, discomfort, severe side effects, and poor specificity. This has demanded an investment in the research of the mechanisms behind the disease progression, evolution, and associated risk factors, and on novel diagnostic and therapeutic techniques. However, advances in the understanding and assessment of breast cancer are dependent on the ability to mimic the properties and microenvironment of tumors in vivo, which can be achieved through experimentation on animal models. This review covers an overview of the main animal models used in breast cancer research, namely in vitro models, in vivo models, in silico models, and other models. For each model, the main characteristics, advantages, and challenges associated to their use are highlighted.This work was supported by Fundação para a Ciência e Tecnologia (FCT), Portugal under the Project Reference UID/DTP/04138/2019 and UIDB/00313/2020. T.F.-G. was supported by FCT, Portugal under the Reference SFRH/BD/147306/2019.info:eu-repo/semantics/publishedVersio

    Planting time for maximization of yield of vinegar plant calyx (Hibiscus sabdariffa L.)

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    Objetivou-se avaliar a produtividade de cálices de Hibiscus sabdariffa L., planta medicinal, em quatro épocas de plantio em Lavras M.G. Os tratamentos foram quatro épocas de plantio (18 de outubro; 15 de novembro; 18 de dezembro de 2001 e 15 de janeiro de 2002) e realizada uma colheita quando praticamente não existiam cálices em desenvolvimento, quase no final do ciclo da planta. Foram considerados os números de cálices por planta, as fitomassas frescas e secas dos cálices e a qualidade. Concluiu-se que a época de plantio influenciou o rendimento por planta e as fitomassas frescas e secas dos cálices, diferindo entre si pelo teste de Tukey a 5%. No plantio de outubro, houve maior rendimento (2.522 kg/ha), com produção de 5,24 vezes a mais em relação ao plantio do mês de janeiro (481 kg/ha). Os plantios nos meses de novembro e dezembro tiveram produções de 1.695 e 1.093 kg.ha-1 de cálices secos, respectivamente, e em relação ao mês de janeiro, a produção foi 3,52 e 2,27 vezes a mais.Deve-se realizar a colheita assim que os cálices estiverem maduros, a fim de preservar a qualidade

    Implications of climate change to the design of protected areas : The case study of small islands (Azores)

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    Climate change is causing shifts in species distributions worldwide. Understanding how species distributions will change with future climate change is thus critical for conservation planning. Impacts on oceanic islands are potentially major given the disproportionate number of endemic species and the consequent risk that local extinctions might become global ones. In this study, we use species climate envelope models to evaluate the current and future potential distributions of Azorean endemic species of bryophytes, vascular plants, and arthropods on the Islands of Terceira and Sao Miguel in the Azores archipelago (Macaronesia). We examined projections of climate change effects on the future distributions of species with particular focus on the current protected areas. We then used spatial planning optimization software (PRION) to evaluate the effectiveness of protected areas at preserving species both in the present and future. We found that contractions of species distributions in protected areas are more likely in the largest and most populated island of Sao Miguel, moving from the coastal areas towards inland where the current protected areas are insufficient and inadequate to tackle species distribution shifts. There will be the need for a revision of the current protected areas in Sao Miguel to allow the sustainable conservation of most species, while in Terceira Island the current protected areas appear to be sufficient. Our study demonstrates the importance of these tools for informing long-term climate change adaptation planning for small islands.Peer reviewe

    Environmental Risk Assessment Based on High-Resolution Spatial Maps of Potentially Toxic Elements Sampled on Stream Sediments of Santiago, Cape Verde

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    Geochemical mapping is the base knowledge to identify the regions of the planet with critical contents of potentially toxic elements from either natural or anthropogenic sources. Sediments, soils and waters are the vehicles which link the inorganic environment to life through the supply of essential macro and micro nutrients. The chemical composition of surface geological materials may cause metabolic changes which may favor the occurrence of endemic diseases in humans. In order to better understand the relationships between environmental geochemistry and public health, we present environmental risk maps of some harmful elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn) in the stream sediments of Santiago, Cape Verde, identifying the potentially harmful areas in this island. The Estimated Background Values (EBV) of Cd, Co, Cr, Ni and V were found to be above the Canadian guidelines for any type of use of stream sediments and also above the target values of the Dutch and United States guidelines. The Probably Effect Concentrations (PEC), above which harmful effects are likely in sediment dwelling organisms, were found for Cr and Ni. Some associations between the geological formations of the island and the composition of stream sediments were identified and confirmed by descriptive statistics and by Principal Component Analysis (PCA). The EBV spatial distribution of the metals and the results of PCA allowed us to establish relationships between the EBV maps and the geological formations. The first two PCA modes indicate that heavy metals in Santiago stream sediments are mainly originated from weathering of underlying bedrocks. The first metal association (Co, V, Cr, and Mn; first PCA mode) consists of elements enriched in basic rocks and compatible elements. The second association of variables (Zn and Cd as opposed to Ni; second PCA mode) appears to be strongly controlled by the composition of alkaline volcanic rocks and pyroclastic rocks. So, the second PCA mode is also considered as a natural lithogenic mode. The third association (Cu and Pb; third PCA mode) consists of elements of anthropogenic origin

    Exercise oxygen uptake efficiency slope independently predicts poor outcome in pulmonary arterial hypertension

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    Universidade Federal de São Paulo UNIFESP, São Paulo Sch Med EPM, Dept Med, Pulm Vasc Grp, São Paulo, BrazilUniversidade Federal de São Paulo, EPM, Dept Med, Div Resp Dis,Pulm Funct & Clin Exercise Physiol U, São Paulo, BrazilQueens Univ, Dept Med, Div Resp & Crit Care Med, Kingston, ON K7L 3N6, CanadaUniversidade Federal de São Paulo UNIFESP, São Paulo Sch Med EPM, Dept Med, Pulm Vasc Grp, São Paulo, BrazilUniversidade Federal de São Paulo, EPM, Dept Med, Div Resp Dis,Pulm Funct & Clin Exercise Physiol U, São Paulo, BrazilWeb of Scienc

    Serum levels of S100B and NSE proteins in Alzheimer's disease patients

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    <p>Abstract</p> <p>Background</p> <p>Alzheimer's disease is the most common dementia in the elderly, and the potential of peripheral biochemical markers as complementary tools in the neuropsychiatric evaluation of these patients has claimed further attention.</p> <p>Methods</p> <p>We evaluated serum levels of S100B and neuron-specific enolase (NSE) in 54 mild, moderate and severe Alzheimer's disease (AD) patients and in 66 community-dwelling elderly. AD patients met the probable NINCDS-ADRDA criteria. Severity of dementia was ascertained by the Clinical Dementia Rating (CDR) scale, cognitive function by the Mini Mental State Examination (MMSE), and neuroimage findings with magnetic resonance imaging. Serum was obtained from all individuals and frozen at -70°C until analysis.</p> <p>Results</p> <p>By comparing both groups, serum S100B levels were lower in AD group, while serum NSE levels were the same both groups. In AD patients, S100B levels were positively correlated with CDR scores (rho = 0.269; p = 0.049) and negatively correlated with MMSE scores (rho = -0.33; <it>P </it>= 0.048). NSE levels decreased in AD patients with higher levels of brain atrophy.</p> <p>Conclusions</p> <p>The findings suggest that serum levels of S100B may be a marker for brain functional condition and serum NSE levels may be a marker for morphological status in AD.</p
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