459 research outputs found

    Performance indicators for reactive distillation design

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    A cost indicator for the design and multi-objective optimization of reactive distillation columns, designated capacity, was introduced in previous work by the authors. The question of this indicator’s effectiveness as a measure of the actual column cost, is herein investigated over a number of designs by comparing it with the value obtained by means of conventional costing procedures. The results show that the level of accuracy obtained when using capacity is satisfactory and certainly acceptable for a preliminary design stage

    Analysis of processing systems involving reaction and distillation : the synthesis of ethyl acetate

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    The integration of reaction and separation into a single process unit, i. e., reactive destillation, may offer several advantages over conventional systems that use a reactor followed by a distillation column. In this paper we explore the operational characteristics of reactive distillation and highlight some of this potential benefits, using the production of ethyl acetate as an illustrative example. With this aim, the two types of system are compared employing different reactor types and a number of performance indicators, such as yield, conversion, purity, specific energy consumption and residence time. A sensitivity analysis is carried out on some variables and parameters, in order to explore and define the distillation columns operating conditions. As expected, results point to a clear advantage of reactive distillation allowing for the azeotrope to be surpassed and for the overcoming of chemical equilibrium, favouring an increase in conversion and product purity, along with reduced operating costs

    Class dissatisfaction and intelligibility of PBL

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    In the context of changing strategies, many teachers are challenged to leave their teaching models and switch to others that bring concepts and principles that often do not meet the previous model in teaching. This change is not trivial, because at the slightest sign of weakness in the new model, there is a tendency to return to the previous model experienced for a long time and even if it proves unsatisfactory, it is a safe haven for the teacher. In this work, data regarding satisfaction with previous teaching models and the intelligibility of teachers about new teaching models that provide for the use of projects will be presented. This is a complement to the work previously presented at PAEE. The teachers' previous conception of a model to structure the PBL will be raised based on data obtained in two stages from a questionnaire conducted with different groups of teachers. The results indicate that the basic principles of PBL are known and understood by teachers, though the same give it a peculiar structure, changing the order of the steps in relation to the standard models of PBL. Teachers also realize the advantage of using PBL, that is, there is the belief that the use of this strategy can contribute to learning. At the same time, there is resistance to the use of these strategies, which may be associated with the doubt that new models can be positive to promote learning.To the teachers that kindly responded to the research. This work was partially supported by CNPq - National Council for Scientific and Technological Development - as scientific initiation sponsorship, and partially supported by FCT – Fundação para a Ciência e Tecnologia - within the R&D Units Project Scope: UIDB/00319/2020

    Localization of MCT2 at peroxisomes is associated with malignant transformation in prostate cancer

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    Previous studies on monocarboxylate transporters expression in prostate cancer (PCa) have shown that monocarboxylate transporter 2 (MCT2) was clearly overexpressed in prostate malignant glands, pointing it out as a putative biomarker for PCa. However, its localization and possible role in PCa cells remained unclear. In this study, we demonstrate that MCT2 localizes mainly at peroxisomes in PCa cells and is able to take advantage of the peroxisomal transport machinery by interacting with Pex19. We have also shown an increase in MCT2 expression from non-malignant to malignant cells that was directly correlated with its peroxisomal localization. Upon analysis of the expression of several peroxisomal ß-oxidation proteins in PIN lesions and PCa cells from a large variety of human prostate samples, we suggest that MCT2 presence at peroxisomes is related to an increase in ß -oxidation levels which may be crucial for malignant transformation. Our results present novel evidence that may not only contribute to the study of PCa development mechanisms but also pinpoint novel targets for cancer therapy.SFRH/BPD/77619/2011PTDC-IMI-MIC-0828-2012Portuguese Foundation for Science and Technology (FCT), refs. SFRH/BD/61027/200

    T-box transcription factor Brachyury is associated with prostate cancer progression and aggressiveness

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    Purpose: Successful therapy of patients with prostate cancer is highly dependent on reliable diagnostic and prognostic biomarkers. Brachyury is considered a negative prognostic factor in colon and lung cancer; however, there are no reports on Brachyury’s expression in prostate cancer. Experimental Design: In this study, we aimed to assess the impact of Brachyury expression in prostate tumorigenesis using a large series of human prostate samples comprising benign tissue, prostate intraepithelial neoplasia (PIN) lesions, localized tumor, and metastatic tissues. The results obtained were compared with what can be inferred from the Oncomine database. In addition, multiple in vitro models of prostate cancer were used to dissect the biologic role of Brachyury in prostate cancer progression. Results: We found that Brachyury is significantly overexpressed in prostate cancer and metastatic tumors when compared with normal tissues, both at protein and at mRNA levels. Brachyury expression in the cytoplasm correlates with highly aggressive tumors, whereas the presence of Brachyury in the nucleus is correlated with tumor invasion. We found that Brachyury-positive cells present higher viability, proliferation, migration, and invasion rates than Brachyury-negative cells. Microarray analysis further showed that genes co-expressed with Brachyury are clustered in oncogenic-related pathways, namely cell motility, cellcycle regulation, and cell metabolism. Conclusions: Collectively, the present study suggests that Brachyury plays an important role in prostate cancer aggressiveness and points, for the first time, to Brachyury as a significant predictor of poor prostate cancer prognosis. Our work paves the way for future studies assessing Brachyury as a possible prostate cancer therapeutic target.This study was supported by the ICVS internal research funds of participating authors and by the FCT project, ref. PTDC/SAU-MET113415/2009. F. Pinto and N. Pertega-Gomes received fellowships from the FCT, ref. SFRH/BD/81369/2011 and SFRH/BD/61027/2009, respectively. R. P. Andrade was funded by Ciencia2007 Program Contract and Programa Operacional Regional do Norte (ON. 2) - NORTE-07-0124-FEDER-000017

    Influence of HOTAIR rs920778 and rs12826786 genetic variants on prostate cancer risk and progression-free survival

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    Aim: Evaluate the impact of the single nucleotide polymorphisms rs920778 and rs12826786 in the long noncoding RNA HOTAIR in the susceptibility and prognosis of prostate cancer (PCa) patients. Patients & methods: HOTAIR single nucleotide polymorphisms were genotyped by restriction fragment length polymorphism in 151 PCa cases and 180 cancer-free controls. Odds ratio, 95% CIs and prognostic significance were calculated. Results: Our data showed no statistically significant associations between HOTAIR polymorphic variants in rs920778 and rs12826786 and PCa susceptibility. However, the CC genotype in rs12826786 was significantly associated with shorter biochemical recurrence-free survival in pT3-stage PCa patients. Conclusion: Our results indicate that HOTAIR rs12826786 CC genotype may be an independent prognostic biomarker in a particular subset of PCa tumors.Fundação para a Ciência e Tecnologia (IF/00601/2012 to BM Costa; SFRH/BD/52287/2013 to AI Oliveira; SFRH/BD/88220/2012 to AX Magalhaes), Fundação Calouste Gulbenkian (BM Costa), Liga Portuguesa Contra o Cancro (BM Costa) and Inter-University Doctoral Programme in Ageing and Chronic Disease (PhDOC; to AI Oliveira and AX Magalhaes). Project co-financed by Programa Operacional Regional do Norte (ON.2-O Novo Norte), Quadro de Referencia Estratégico Nacional (QREN), Fundo Europeu de Desenvolvimento Regional (FEDER) and a grant (74-CI-IPOP) from Research Center of Portuguese Oncology Institute of Porto (C Jeronimo).info:eu-repo/semantics/publishedVersio

    Fast calculation of spectral optical properties and pigment content detection in human normal and pathological kidney

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    A fast calculation method was used to obtain the spectral optical properties of human normal and pathological (chromophobe renal cell carcinoma) kidney tissues. Using total transmittance, total reflectance and collimated transmittance spectra acquired from ex vivo kidney samples, the spectral optical properties of both tissues, namely the absorption, the scattering and the reduced scattering coefficients, as well as the scattering anisotropy, dispersion and light penetration depth, were calculated between 200 and 1000 nm. Analysis of the mean ab sorption coefficient spectra of the kidney tissues showed that both contain melanin and lipofuscin, and that 83 % of the melanin in the normal kidney converts into lipofuscin in the pathological kidney.info:eu-repo/semantics/publishedVersio

    Tissue optical clearing as a diagnostic tool for tissue pathology differentiation

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    With the objective of developing a diagnostic tool

    The loss of NKX3.1 expression in testicular – and prostate – cancers is not caused by promoter hypermethylation

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    BACKGROUND: Recent studies have demonstrated that the NKX3.1 protein is commonly down-regulated in testicular germ cell tumors (TGCTs) and prostate carcinomas. The homeobox gene NKX3.1 maps to chromosome band 8p21, which is a region frequently lost in prostate cancer, but not in TGCT. Mutations have not been reported in the NKX3.1 sequence, and the gene is hypothesized to be epigenetically inactivated. In the present study we examined the methylation status of the NKX3.1 promoter in relevant primary tumors and cell lines: primary TGCTs (n = 55), intratubular germ cell neoplasias (n = 7), germ cell tumor cell lines (n = 3), primary prostate adenocarcinomas (n = 20), and prostate cancer cell lines (n = 3) by methylation-specific PCR and bisulphite sequencing. RESULTS AND CONCLUSIONS: Down-regulation of NKX3.1 expression was generally not caused by promoter hypermethylation, which was only found in one TGCT. However, other epigenetic mechanisms, such as modulation of chromatin structure or modifications of histones, may explain the lack of NKX3.1 expression, which is seen in most TGCTs and prostate cancer specimens

    Secreted extracellular vesicle molecular cargo as a novel liquid biopsy diagnostics of central nervous system diseases

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    Secreted extracellular vesicles (EVs) are heterogeneous cell-derived membranous granules which carry a large diversity of molecules and participate in intercellular communication by transferring these molecules to target cells by endocytosis. In the last decade, EVs role in several pathological conditions, from etiology to disease progression or therapy evasion, has been consolidated, including in central nervous system (CNS)-related disorders. For this review, we performed a systematic search of original works published, reporting the presence of molecular components expressed in the CNS via EVs, which have been purified from plasma, serum or cerebrospinal fluid. Our aim is to provide a list of molecular EV components that have been identified from both nonpathological conditions and the most common CNS-related disorders. We discuss the methods used to isolate and enrich EVs from specific CNS-cells and the relevance of its components in each disease context.This research was funded by the MindGaP-H2020-FETOPEN-2018-2020, Grant agreement ID: 829040. S.M.-R., C.C.-M., and J.P. hold a fellowship from MindGaP.info:eu-repo/semantics/publishedVersio
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