3,183 research outputs found

    Customer knowledge and behavior on the use of food refrigerated display cabinets: A Portuguese case

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    This article presents a study on customer knowledge and habits regarding the use of refrigerated display cabinets (RDC). The study was carried out on a sample of Portuguese retail stores’ customers, using a questionnaire survey available through an Internet platform. The sample consisted of 136 individuals, who voluntarily participated in the study. Questions included the characterization of the sociodemographic population involved. The questionnaire included different questions to related with RDC, namely customer knowledge about the appearance of each RDC equipment, questions to evaluate the respondents’ perception about the advantages and disadvantages related to open or glass-door closed RDC, questions to assess the participants’ habits and behavior when purchasing food products from glass-door closed RDC (frequency and duration of door open), questions to characterize the consumers’ habits on purchasing food products from RDC, and also questions to characterize the consumers’ shopping attitudes in the context of the COVID-19 pandemic, caused by SARS-CoV-2. The results seem to indicate that customers prefer closed RDC; for example, 61.8% of participants prefer products preserved in glass-door closed RDC, against 6.6% that admit to preferring products preserved in open RDC. Therefore, we can deduce that the existence of doors does not appear to be an obstacle to purchasing food products. Regarding the use of glass-door closed RDC, 80.1% of the participants say they just open the door once, and 53.7% of the costumers believe they keep the door open in the interval [4‒6 s]. This indicates that Portuguese customers are quite well informed about food safety issues and seem to follow assertive attitudes when purchasing food products from RDC. This study reinforces the benefits of replacing open RDC by closed glass-doors allowing significant energy savings.info:eu-repo/semantics/publishedVersio

    Altered cogs of the clock: Insights into the embryonic etiology of spondylocostal dysostosis

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    Spondylocostal dysostosis (SCDO) is a rare heritable congenital condition, characterized by multiple severe malformations of the vertebrae and ribs. Great advances were made in the last decades at the clinical level, by identifying the genetic mutations underlying the different forms of the disease. These were matched by extraordinary findings in the Developmental Biology field, which elucidated the cellular and molecular mechanisms involved in embryo body segmentation into the precursors of the axial skeleton. Of particular relevance was the discovery of the somitogenesis molecular clock that controls the progression of somite boundary formation over time. An overview of these concepts is presented, including the evidence obtained from animal models on the embryonic origins of the mutant-dependent disease. Evidence of an environmental contribution to the severity of the disease is discussed. Finally, a brief reference is made to emerging in vitro models of human somitogenesis which are being employed to model the molecular and cellular events occurring in SCDO. These represent great promise for understanding this and other human diseases and for the development of more efficient therapeutic approaches.PTDC/BEX-BID/5410/2014, SFRH/BD/146043/2019, UID/BIM/04773/2019info:eu-repo/semantics/publishedVersio

    Features of the Extension of a Statistical Measure of Complexity to Continuous Systems

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    We discuss some aspects of the extension to continuous systems of a statistical measure of complexity introduced by Lopez-Ruiz, Mancini and Calbet (LMC) [Phys. Lett. A 209 (1995) 321]. In general, the extension of a magnitude from the discrete to the continuous case is not a trivial process and requires some choice. In the present study, several possibilities appear available. One of them is examined in detail. Some interesting properties desirable for any magnitude of complexity are discovered on this particular extension.Comment: 22 pages, 0 figure

    Superfícies bi-harmonicas de tipo gráfico em R3

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    In this work, we study biharmonic surfaces that are parameterized by biharmonic coordinate functions. We study a class of biharmonic surfaces called graph-type biharmonic surfaces. Also, we define a class of surfaces associated to two harmonic functions (FH2A-surfaces), these surfaces satisfy a relation between the Gaussian curvature, the projection of the Gauss map on a fixed plane and two harmonic functions. We show that a particular class of graph-type biharmonic surfaces are FH2A-surfaces. Finally, we classify the FH2A-surfaces of rotation.Neste artigo, estudamos superfícies bi-harmonicas que sao parametrizadas por funcoes coordenadas biharmonicas. Estudamos uma classe de superfícies bi-harmonicas, chamadas superficies bi-harmonicas de tipo gráfico. Tambem, definimos uma classe de superfícies associadas a duas funcoes harmonicas (FH2Asurfaces), essas superfícies satisfazem uma relacao entre a curvatura Gaussiana, a projecao da aplicacao de Gauss sobre um plano fixo e duas funcoes harmonicas. Mostramos que uma classe particular de superfícies bi-harmonicas de tipo gráfico sao FH2A-surfaces. Finalmente, classificamos as FH2A-surfaces de rotacao

    Label-free Detection of Microcystin-LR in Waters Using Real-Time Potentiometric Biosensors Based on Single-Walled Carbon Nanotubes Imprinted Polymers

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    Microcystin-LR (MC-LR) is a dangerous toxin found in environmental waters, quantified by high performance liquid chromatography and/or enzyme-linked immunosorbent assays. Quick, low cost and on-site analysis is thus required to ensure human safety and wide screening programs. This work proposes label-free potentiometric sensors made of solid-contact electrodes coated with a surface imprinted polymer on the surface of Multi-Walled Carbon NanoTubes (CNTs) incorporated in a polyvinyl chloride membrane. The imprinting effect was checked by using non-imprinted materials. The MC-LR sensitive sensors were evaluated, characterized and applied successfully in spiked environmental waters. The presented method offered the advantages of low cost, portability, easy operation and suitability for adaptation to flow methods

    Revealing the Dusty Warm Absorber in MCG--6-30-15 with the Chandra HETG

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    We present detailed evidence for a warm absorber in the Seyfert 1 galaxy MCG--6-30-15 and dispute earlier claims for relativistic O line emission. The HETG spectra show numerous narrow, unresolved (FWHM < 200 km/s) absorption lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and Fe. The O VII edge and 1s^2--1snp resonance line series to n=9 are clearly detected at rest in the AGN frame. We attribute previous reports of an apparently highly redshifted O VII edge to the 1s^2--1snp (n > 5) O VII resonance lines, and a neutral Fe L absorption complex. The shape of the Fe L feature is nearly identical to that seen in the spectra of several X-ray binaries, and in laboratory data. The implied dust column density agrees with that obtained from reddening studies, and gives the first direct X-ray evidence for dust embedded in a warm absorber. The O VIII resonance lines and weak edge are also detected, and the spectral rollover below 2 keV is explained by the superposition of numerous absorption lines and edges. We identify, for the first time, a KLL resonance in the O VI photoabsorption cross section, giving a measure of the O VI column density. The O VII (f) emission detected at the systemic velocity implies a covering fraction of ~5% (depending on the observed vs. time-averaged ionizing flux). Our observations show that a dusty warm absorber model is not only adequate to explain all the spectral features > 0.48 keV (< 26 \AA) the data REQUIRE it. This contradicts the interpretation of Branduardi-Raymont et al. (2001) that this spectral region is dominated by highly relativistic line emission from the vicinity of the black hole.Comment: 4.5 pages, 1 color figure, accepted (April 2001) for publication in ApJL, not many changes from the initial submission - updated/added some measuements for the O VII resonance series, and added a discussion about FeO2 grain

    Anti-hepatocellular carcinoma activity using human HepG2 cells and hepatotoxicity of 6-substituted methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate derivatives: in vitro evaluation, cell cycle analysis and QSAR studies

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    Hepatocellular carcinoma (HCC) is a highly complex cancer, resistant to commonly used treatments and new therapeutic agents are urgently needed. A total of thirty-two thieno[3,2-b]pyridine derivatives of two series: methyl 3-amino-6-(hetero)arylthieno[3,2-b]pyridine-2-carboxylates (1a-1t) and methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates (2a-2n), previously prepared by some of us, were evaluated as new potential anti-HCC agents by studying their in vitro cell growth inhibition on human HepG2 cells and hepatotoxicity using a porcine liver primary cell culture (PLP1). The presence of amino groups linked to a benzene moiety emerges as the key element for the anti-HCC activity. The methyl 3-amino-6-[(3-aminophenyl)ethynyl]thieno[3,2-b]pyridine-2-carboxylate (2f) is the most potent compound presenting GI50 values on HepG2 cells of 1.2 μM compared to 2.9 μM of the positive control ellipticine, with no observed hepatotoxicity (PLP1 GI50>125 μM against 3.3 μM of ellipticine). Moreover this compound changes the cell cycle profile of the HepG2 cells, causing a decrease in the % of cells in the S phase and a cell cycle arrest in the G2/M phase. QSAR studies were also performed and the correlations obtained using molecular and 1D descriptors revealed the importance of the presence of amino groups and hydrogen bond donors for anti-HCC activity, and hydrogen bond acceptors for hepatotoxicity. The best correlations were obtained with 3D descriptors belonging to different subcategories for anti-HCC activity and hepatotoxicity, respectively. These results point to different molecular mechanisms of action of the compounds in anti-HCC activity and hepatotoxicity. This work presents some promising thieno[3,2-b]pyridine derivatives for potential use in the therapy of HCC. These compounds can also be used as scaffolds for further synthesis of more potent analogues.FCT, FEDER/COMPETE/QREN/E

    Anion Colorimetric Chemosensor Based on a Benzimidazole-Functionalized BODIPY Derivative

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    A BODIPY derivative bearing a benzimidazole unit at position 2 and an electron donor group (anthracene) at the meso position was synthetized and characterized by the usual spectroscopic techniques. The evaluation of the compound as a colorimetric chemosensor was performed in solutions of acetonitrile/water (75:25) in the presence of several anions (HSO4−, NO3−, H2PO4−, CN−, BzO−, ClO4−, Br−, F−, I− and CH3CO2−) with biomedical and environmental relevance. The in-vestigated BODIPY derivative demonstrated a selective color change from pink to yellow upon interaction with a hydrogen sulfate anion (HSO4−).The authors acknowledge Fundação para a Ciência e Tecnologia-FCT (Portugal) for funding through CQUM (UID/QUI/00686/2020) and project PTDC/QUI-COL/28052/2017 and a PhD grant to. R. C. R. Gonçalves (SFRH/BD/05278/2020). The NMR spectrometer Bruker Avance III 400 was part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and FCT

    Heterocyclic Aldehydes Based on Thieno[3,2-b]thiophene Core: Synthesis and Preliminary Studies as Ion Optical Chemosensors

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    Heterocyclic aldehydes show a variety of optical properties and the versatility of their reactivity allows them to yield a wide range of more complex compounds, with application in areas such as medicinal, materials and supramolecular chemistry. The biological and environmental relevance of certain molecules and ions turns them into targets for the design of molecular recognition systems. Recently, heterocyclic aldehydes have been reported in the literature as ion chemosensors. Following the group's work on optical chemosensors, for the detection and quantification of ions and molecules with environmental and medicinal relevance, this work reports the synthesis and characterization of two heterocyclic aldehydes based on the thieno[3,2-b]thiophene core, by Suzuki coupling, as well as the synthesis of the corresponding precursors. Preliminary chemosensory studies for the synthesized heterocyclic aldehydes in the presence of selected cations were also performed, in solution, in order to determine their potential application as optical chemosensors

    A meso-triphenylamine-BODIPY derivative for the optical chemosensing of metal ions

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    The design and synthesis of organic molecules for recognition of biologically/environmentally important metal ions has emerged as a highly regarded research field. The BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) core is a versatile signaling molecule that can be fine-tuned with functional groups to create selective binding sites to improve its optical proper-ties. As an extension of the work developed in our research group, we report the synthesis and characterization of a BODIPY functionalized with triphenylamino and a formyl group at the meso and 2-position, respectively, for the highly selective detection of Cu2+ and Fe3+. The preliminary study of the BODIPY derivative as optical chemosensor was carried out in acetonitrile solution in the presence of different cations, and interactions with Cu2+ and Fe3+ induced a perceptible color change. UV-visible titrations showed changes in the absorption spectra upon the addition of three equivalents of each cation, with the appearance of a new absorption band at 693 nm.This research was funded by Foundation for Science and Technology (FCT) for financial support to CQ/UM (UID/QUI/00686/2020) and project PTDC/QUI-COL/28052/2017. Thanks are also due to Fundação para a Ciência e Tecnologia (Portugal) for financial support to the Portuguese NMR network (PTNMR, Bruker Avance III 400-Univ. Minho)
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