797 research outputs found

    Curvas dadas por la intersección transversal de dos superficies en el espacio tridimesional de Minkowski

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    In this paper, we study the differential geometry of the transversal intersection curve of two surfaces in Minkowski 3-space, where each pair satisfies the following types spacelike-lightlike, timelike-lightlike and lightlike-lightlike. Surfaces are generally give by their parametric or implicit equations, then the surfacesurface intersection problem appear commonly as parametric-parametric, parametric-implicit and implicitimplicit.We derive the Frenet frame, Darboux frame, curvature, torsion, normal curvature and geodesic curvatures of transversal intersections for all types of intersection problems. We show the intersection curve may be spacelike (timelike, lightlike or pseudo null) curve. Finally, we show our methods by given several examples.En este artículo, estudiamos la geometría diferencial de la curva dada por la intersección transversal de dos superficies en el espacio tridimensional de Minkowski donde cada par satisface los siguientes tipos de superficies; tipo espacio - tipo luz, tipo tiempo - tipo luz y tipo luz - tipo luz. Generalmente, las superficies están dadas por sus ecuaciones paramétricas o implícitas, entonces el problema de intersección superficie superficie aparece comunmente como paramétrico-paramétrico, paramétrico-implícito e implícito-implícito. Obtenemos el Referencial de Frenet, el Referencial de Darboux, la curvatura, la torsión, la curvatura normal y las curvaturas geodésicas de las intersecciones transversales para todos los tipos de problemas de intersección. Mostramos que la curva de intersección puede ser una curva similar a una curva tipo espacio (tipo tiempo, tipo luz o pseudo nula). Finalmente, mostramos nuestros métodos por varios ejemplos

    On the accumulation of organic matter on the southeastern Brazilian continental shelf: A case study based on a sediment core from the shelf off Rio de Janeiro

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    Sterol and fatty acid biomarkers and isotopic composition (delta 13C and delta 15N) of bulk organic matter (OM) were quantified in a sediment core to characterize the accumulation of autochthonous OM in an area on the continental shelf adjacent to Rio de Janeiro State. In the sediment surface (0-1 cm) the concentration of total sterols and fatty acids was at least one order of magnitude higher than that measured deeper down in the core and was dominated by labile and planktonic-derived biomarker compounds. These results suggest, as is confirmed by multivariate statistical analysis, the occurrence of an event of enhanced primary production in the water column and efficient export of particles to the bottom. Similar conditions have been observed at Cabo Frio, located 150 km to the north of our study site, during an upwelling event, suggesting that such events may exert a regional influence on primary production on the south-eastern Brazilian continental shelf. Beyond the signatures from this event, the presence of biomarker compounds from vascular plants suggests the additional influence of an outflow from Guanabara Bay at the study site. These results point to the need for further investigation of the relative influence of physical forcings and continental inputs on the biogeochemical processes on the section of the continental shelf considered in the present study

    Effect of stocking density and use of environmental enrichment materials on the welfare and the performance of pigs in the growth and finishing phases

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    Aim of study: To evaluate the effects of stocking density and the use of environmental enrichment (EE) objects on the welfare and the performance of pigs in the growing and finishing phases.Area of study: The southern region of Brazil.Material and methods: A total of 240 pigs, 120 immunocastrated males and 120 females, with an initial weight of 22.38 ± 2.38 kg and mean age of 65 days, were submitted to two stocking densities conditions (0.85 and 1.28 m²pig) with and without EE for 117 days. The experimental design was a 2×2×2 factorial (two categories, two densities, and two EE conditions), with six replicates. Performance variables and behavior were evaluated.Main results: For stocking density, there was a significant difference in the finishing phase from 148 to 161 days of age for the final weight (FW), average daily weight gain (ADWG), and feed conversion rate (FCR). For the EE factor, there was no difference in any of the phases or in the overall period. In the overall period, the higher availability of space improved the results of FW (140.56 kg vs 136.63 kg), ADWG (1.005 kg vs 0.974 kg), and FCR (2.05 vs 2.10). There was no effect of EE, stocking densities, or their interaction on the frequency of different behaviors of the pigs in the growth and finishing phases.Research highlights: There was no effect of interactions between enriched environments, stocking densities, and sex for animal performance and behavioral frequencies; however, differences between the factors were observed separately. The higher availability of space improved the results of FW, ADWG, and FCR

    MULTILETRAMENTOS NA EDUCAÇÃO SUPERIOR TECNOLÓGICA:: UM ESTUDO SOBRE A PRODUÇÃO CIENTÍFICA

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    Na educação superior tecnológica, as diferentes formas de linguagem e comunicação contribuem para o efetivo processo de ensino e aprendizagem para a formação do tecnólogo. Fundamenta-se teoricamente em estudos sobre a educação profissional, a educação superior tecnológica no Brasil e multiletramentos. Neste artigo, objetiva-se apresentar um levantamento bibliométrico e analítico da produção científica acadêmica, no que diz respeito ao tema multiletramentos e o ensino superior tecnológico, abrangendo o período de 2010 a 2021, com a intenção de identificar a pertinência e a relevância dos multiletramentos nas práticas de ensino do professor de educação superior tecnológica. Este estudo possibilita afirmar que o termo multiletramentos é relevante para as práticas docentes nesta área

    Mast cell repopulation of the peritoneal cavity: contribution of mast cell progenitors versus bone marrow derived committed mast cell precursors

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    <p>Abstract</p> <p>Background</p> <p>Mast cells have recently gained new importance as immunoregulatory cells that are involved in numerous pathological processes. One result of these processes is an increase in mast cell numbers at peripheral sites. This study was undertaken to determine the mast cell response in the peritoneal cavity and bone marrow during repopulation of the peritoneal cavity in rats.</p> <p>Results</p> <p>Two mast cell specific antibodies, mAb AA4 and mAb BGD6, were used to distinguish the committed mast cell precursor from more mature mast cells. The peritoneal cavity was depleted of mast cells using distilled water. Twelve hours after distilled water injection, very immature mast cells could be isolated from the blood and by 48 hours were present in the peritoneal cavity. At this same time the percentage of mast cells in mitosis increased fourfold. Mast cell depletion of the peritoneal cavity also reduced the total number of mast cells in the bone marrow, but increased the number of mast cell committed precursors.</p> <p>Conclusions</p> <p>In response to mast cell depletion of the peritoneal cavity, a mast cell progenitor is released into the circulation and participates in repopulation of the peritoneal cavity, while the committed mast cell precursor is retained in the bone marrow.</p

    Hiperfosfatasemia transitória benigna na infância

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    Benign transient hyperphosphatasemia of childhood (BTHC) is a rather unknown condition that is associated with a benign state and a good prognosis. BTHC is defined by a sudden and transitory elevation of serum concentration of alkaline phosphatase in healthy children. The etiology of this disorder remains unclear, however the impaired clearance of the enzyme in the circulation seems to be a possible mechanism. To make the current knowledge about BTHC well known , the most relevant papers published since the first description of this condition, in 1954, were selected in Medline database. The diagnostic criteria of BTHC are: being younger than five years, absence of symptoms or presence of symptoms associated with unrelated diseases, without clinic or biochemical evidence of bone or liver diseases. Alkaline phosphatase elevation ranges from 3 to 50 times the upper normal value for age. The isoenzyme analysis shows an elevation in bone and/or liver fractions. Serum alkaline phosphatase levels return to normal in four months. Elevation in serum levels of alkaline phosphatase has also been found in disorders such as asymptomatic and symptomatic persistent familial hyperphosphatasemia and persistent nonfamilial hyperphosphatasemia. Taking into consideration the BTHC is essential in the distinct diagnosis of serum alkaline phosphatase elevation in children when no reasonable cause is detected, thus avoiding unnecessary and expensive procedures during the diagnostic investigation.A hiperfosfatasemia transitória benigna na infância (HTBI) é uma condição pouco conhecida, que se traduz por um estado benigno e de bom prognóstico. A HTBI resulta do aumento súbito e transitório na concentração sérica da fosfatase alcalina (FA) em crianças sadias. A sua etiopatogenia é ainda incerta, porém a diminuição do clearance da enzima na circulação tem sido considerada o mecanismo mais provável. Para divulgar os conhecimentos atuais acerca do diagnóstico da HTBI, foram selecionados, no Medline, os artigos de periódicos médicos internacionais mais relevantes desde a descrição inicial desta condição, em 1954. Os critérios para diagnóstico de HTBI são: acometer crianças com idade inferior a cinco anos, ausência de sintomas ou presença de sintomas associados a doenças não relacionadas, sem evidência clínica ou laboratorial de doença óssea ou hepática. A elevação da fosfatase alcalina varia entre 3 e 50 vezes o limite superior do valor para a idade. A análise das isoenzimas mostra elevação das formas óssea e hepática. Os níveis séricos da fosfatase alcalina retornam ao normal em quatro meses. A elevação sérica da fosfatase alcalina foi relatada em patologias como hiperfosfatasemia familiar persistente assintomática e sintomática e hiperfosfatasemia persistente não-familiar. É indispensável que a HTBI seja considerada no diagnóstico diferencial de um aumento considerável dos níveis séricos de fosfatase alcalina em crianças, sem que seja detectada uma causa óbvia, o que evitará procedimentos desnecessários e dispendiosos durante a investigação diagnóstica

    Marfan syndrome with a complex chromosomal rearrangement including deletion of the FBN1 gene

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    <p>Abstract</p> <p>Background</p> <p>The majority of Marfan syndrome (MFS) cases is caused by mutations in the fibrillin-1 gene (<it>FBN1</it>), mapped to chromosome 15q21.1. Only few reports on deletions including the whole <it>FBN1 </it>gene, detected by molecular cytogenetic techniques, were found in literature.</p> <p>Results</p> <p>We report here on a female patient with clinical symptoms of the MFS spectrum plus craniostenosis, hypothyroidism and intellectual deficiency who presents a 1.9 Mb deletion, including the <it>FBN1 </it>gene and a complex rearrangement with eight breakpoints involving chromosomes 6, 12 and 15.</p> <p>Discussion</p> <p>This is the first report of MFS with a complex chromosome rearrangement involving a deletion of <it>FBN1 </it>and contiguous genes. In addition to the typical clinical findings of the Marfan syndrome due to <it>FBN1 </it>gene haploinsufficiency, the patient presents features which may be due to the other gene deletions and possibly to the complex chromosome rearrangement.</p

    A retrospective analysis of clinicopathological and prognostic characteristics of ovarian tumors in the State of Espírito Santo, Brazil

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    <p>Abstract</p> <p>Background</p> <p>Ovarian cancer is sixth most common cancer among women and the leading cause of death in women with gynecological malignancies. Despite the great impact ovarian cancer has on women's health and its great impact in public economy, Brazil still lacks valuable information concerning epidemiological aspects of this disease</p> <p>Methods</p> <p>We've compiled clinical data of all ovarian tumors registered at the two public hospitals of reference (1997 - 2007), such as: patients' age at diagnosis, tumor histological type, tumor stage, chemotherapy regimens, chemotherapy responsiveness, disease-free survival, and overall survival.</p> <p>Results</p> <p>Women's mean age at diagnosis was 54.67 ± 13.84 for ovarian cancer, 46.15 ± 11.15 for borderline tumors, and 42.01 ± 15.06 for adenomas. Among epithelial ovarian cancer cases, 30.1% were of serous, 13.7% were of mucinous, and 13.7% were of endometrioid type; exceptionally serous carcinoma was diagnosed in women younger than 30 years old. Endometrioid cancer had lower disease-free survival than others (p < 0.05). Cases were predominantly diagnosed as poor prognosis disease (FIGO III and IV, 56.2%). Regarding responsiveness to platinum-based therapy, 17.1% of patients were resistant, whereas 24.6%, susceptible. From these, we found equally responsiveness to platinum alone or its association with paclitaxel or cyclophosphamide.</p> <p>Discussion</p> <p>Our data agreed with other studies regarding mean patients' age at diagnosis, histological type frequency, FIGO stages distribution, and chemotherapy regimens. However, the histological type distribution, with equal contribution of mucinous and endometrioid types seems to be a unique characteristic of the studied highly miscegenated population.</p> <p>Conclusion</p> <p>We have enlighten the profile of the studied ovarian cancer population, which might enable the development of more efficient political strategies to control this malignancy that is the fifth leading cause of cancer-related deaths among women.</p

    Perillaldehyde 1,2-epoxide loaded SLN-tailored mAb: production, physicochemical characterization and in vitro cytotoxicity profile in MCF-7 cell lines

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    We have developed a new cationic solid lipid nanoparticle (SLN) formulation, composed of Compritol ATO 888, poloxamer 188 and cetyltrimethylammonium bromide (CTAB), to load perillaldehyde 1,2-epoxide, and surface-tailored with a monoclonal antibody for site-specific targeting of human epithelial growth receptor 2 (HER2). Perillaldehyde 1,2-epoxide-loaded cationic SLN (cPa-SLN), with a mean particle size (z-Ave) of 275.31 ± 4.78 nm and polydispersity index (PI) of 0.303 ± 0.081, were produced by high shear homogenization. An encapsulation efficiency of cPa-SLN above 80% was achieved. The release of perillaldehyde 1,2-epoxide from cationic SLN followed the Korsemeyer–Peppas kinetic model, which is typically seen in nanoparticle formulations. The lipid peroxidation of cPa-SLN was assessed by the capacity to produce thiobarbituric acid-reactive substances, while the antioxidant activity was determined by the capacity to scavenge the stable radical DPPH. The surface functionalization of cPa-SLN with the antibody was done via streptavidin-biotin interaction, monitoring z-Ave, PI and ZP of the obtained assembly (cPa-SLN-SAb), as well as its stability in phosphate buffer. The effect of plain cationic SLN (c-SLN, monoterpene free), cPa-SLN and cPa-SLN-SAb onto the MCF-7 cell lines was evaluated in a concentration range from 0.01 to 0.1 mg/mL, confirming that streptavidin adsorption onto cPa-SLN-SAb improved the cell viability in comparison to the cationic cPa-SLN.The authors wish to acknowledge the financial support from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), and from FAPITEC/SE (Fundação de Apoio à Pesquisa e Inovação Tecnológica do Estado de Sergipe). E.B. Souto acknowledges the sponsorship of the projects M-ERA-NET-0004/2015-PAIRED and UIDB/04469/2020, receiving support from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio
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