136 research outputs found
Investigation into Brazilian Palygorskite for Its Potential Use as Pharmaceutical Excipient: Perspectives and Applications
Palygorskite is an aluminum and magnesium silicate characterized by its fibrous morphology, providing it with great versatility in industrial applications, including pharmaceuticals. Although most of the reserves are in the United States, in recent years occurrences of commercially exploited deposits in Brazil have been recorded, mainly in the country’s northeast region. This has motivated this study, which analyzes raw Brazilian palygorskite compared to a commercial sample (Pharmasorb® colloidal) to demonstrate its pharmaceutical potential. The chemical and mineral composition of the samples were evaluated for surface properties, granulometry, morphology, crystallography, thermal analysis, and spectroscopy. Raw palygorskite presented 67% purity, against 74% for Pharmasorb® colloidal. The percentage purity relates to the presence of contaminants, mainly carbonates and quartz (harmless under conventional conditions of pharmaceutical use). Furthermore, it was possible to confirm the chemical composition of these phyllosilicates, formed primarily of silicon, aluminum, and magnesium oxides. The crystallographic and spectroscopic profiles were consistent in both samples, showing characteristic peaks for palygorskite (2θ = 8.3°) and bands attributed to fibrous phyllosilicates below 1200 cm−1, respectively. The thermal analysis allowed the identification of the main events of palygorskite, with slight differences between the evaluated samples: loss of water adsorbed onto the surface (~85 °C), removal of water contained in the channels (~200 °C), coordinated water loss (~475 °C), and, finally, the dehydroxylation (>620 °C). The physicochemical characteristics of raw palygorskite align with pharmacopeial specifications, exhibiting a high specific surface area (122 m2/g), moderately negative charge (−13.1 mV), and compliance with the required limits for heavy metals and arsenic. These favorable technical attributes indicate promising prospects for its use as a pharmaceutical ingredient in the production of medicines and cosmetics.CAPES, grant number 88887.131333/2016-0
Combining experiments and in silico modeling to infer the role of adhesion and proliferation on the collective dynamics of cells
The collective dynamics of cells on surfaces and interfaces poses technological and theoretical challenges in the study of morphogenesis, tissue engineering, and cancer. Different mechanisms are at play, including, cellâ cell adhesion, cell motility, and proliferation. However, the relative importance of each one is elusive. Here, experiments with a culture of glioblastoma multiforme cells on a substrate are combined with in silico modeling to infer the rate of each mechanism. By parametrizing these rates, the time-dependence of the spatial correlation observed experimentally is reproduced. The obtained results suggest a reduction in cellâ cell adhesion with the density of cells. The reason for such reduction and possible implications for the collective dynamics of cancer cells are discussed.e Portuguese Foundation for Science and Technology (FCT)
under Contracts no. PTDC/FIS-MAC/28146/2017 (LISBOA-01-0145-FEDER-028146), UIDB/00618/2020, and
UIDP/00618/2020. F.R.M. also acknowledges FCT for her contract under the Transitional Rule DL 57/2016
(CTTI-57/18-I3BS(5)
O FENÔMENO DA GUERRA NAS RELAÇÕES INTERNACIONAIS A PARTIR DOS PARADIGMAS REALISTA E LIBERAL
O estudo do fenômeno da guerra ocupa lugar central na disciplina de Relações Internacionais desde o seu surgimento, tendo sido discutida sob diferentes perspectivas. O presente artigo se propõe a descrever o percurso dessa discussão nas principais vertentes teóricas dos paradigmas realista e liberal, começando pelos pensamento clássico e moderno que serviu como alicerce para o seu desenvolvimento até chegar nas perspectivas que ganharam visibilidade no contexto internacional do pós-Guerra Fria, o neoliberalismo e o neorrealismo
LINFOMA EM BOVINO ABATIDO EM ABATEDOURO FRIGORÍFICO SOB SERVIÇO DE INSPEÇÃO FEDERAL
Bovine lymphosarcoma, also known as malignant lymphoma and bovine leukemia, is a lymphoid neoplasm that affects adult animals, evolving in an enzootic way. This work reports a case of bovine lymphoma in an animal slaughtered in a slaughterhouse with a Federal Inspection Service (SIF) in the state of Maranhão. The animal presented post-mortem signs that are compatible with the disease, such as: generalized enlargement of lymph nodes in different regions, accompanied by a loss in the morphological pattern, making it impossible to distinguish the cortex and spinal cord. In the histopathological examination, histopathology showed evidence of infiltration of round neoplastic cells in the lymph node parenchyma. The histological changes associated with multicentric lesions and characteristics of the animal (adult) suggest an infectious etiology associated with the Bovine Leukemia Virus (bovine enzootic leukosis) allowing the diagnosis of Bovine Lymphoma.O linfoma maligno bovino, também conhecido por linfossarcoma ou leucemia bovina, é uma neoplasia linfóide que acomete preferencialmente animais adultos, evoluindo de forma enzoótica. Esse trabalho teve como objetivo relatar um caso de linfoma bovino em um animal abatido em abatedouro frigorifico sob Serviço de Inspeção Federal (SIF) no estado do Maranhão. O animal apresentava, no post-mortem, lesões compatíveis com a enfermidade, como: aumento generalizado dos linfonodos de diferentes regiões, acompanhado de perda no padrão morfológico, não sendo possível a distinção do córtex e da medula. No exame histopatológico, foi evidenciada a infiltração de células neoplásicas redondas no parênquima do nodo linfático. As alterações histológicas associadas as lesões multicêntricas e características do animal (adulto) sugerem etiologia infecciosa associada ao Vírus da Leucemia Bovina (leucose enzoótica bovina) permitindo o diagnóstico de Linfoma Bovino
Anestesia intra-articular com ropivacaína para diagnóstico de claudicação em cães
A anestesia intra-articular na medicina veterinária é uma prática recente e usada para alívio da dor em cirurgias artroscópicas, entretanto uso para o diagnóstico de claudicação na clínica médica de cães é infrequente. A técnica pode ser realizada em qualquer articulação como forma de localizar a fonte da claudicação. Nesta pesquisa foram avaliados 20 animais, os quais foram identificados claudicando por dois avaliadores veterinários, visualmente e por meio de filmagem (normal e “slow motion”), antes e após a administração intra-articular de ropivacaína 0,5% na dose de 0,5mg/kg. Com 48 h, sete e 30 dias após a administração não foram verificados a ocorrência de agravamento da claudicação assim como efeitos sistêmicos indesejáveis. Os resultados permitem sugerir que a anestesia intra-articular oferece a possibilidade de determinar que o problema é situado numa única articulação, assim como além de haver uma articulação afetada outras articulações ou estruturas não passíveis de anestesia intra-articular podem estar afetadas. Em 10 animais (50%), o diagnóstico final correspondeu ao da pré-anestesia intra-articular, em cinco confirmou-se a suspeita inicial, mas foi identificada outra afecção concomitante e em três casos houve mudança de diagnóstico. Conclui-se que a ropivacaína quando administrada em cães pela via intra-articular nessa dosagem não tem efeitos deletérios e funciona como método de diagnóstico seguro e eficiente para localizar a fonte da claudicação nesses pacientes
Philosophical Research in Brazil: A Structural Topic Modeling Approach with a focus on Temporal and Gender Trends
This paper employs structural topic modeling (STM), a text-mining technique, to describe the academic philosophy landscape in Brazil. Based on a public national database, a corpus consisting of 12,515 abstracts of monographs (theses and dissertations) defended in Philosophy Graduate Programs between 1991 and 2021 was compiled. The final STM model identified 74 meaningful research topics, clustered into 7 thematic categories. This study discusses the prevalence of the most significant topics and categories, their trends across three decades and their (positive or negative) association with the supervisor’s gender. Results show the first empirical evidence that Brazilian philosophical research exhibits a greater focus on philosophers and their works, rather than on specific themes or problems, aligning with common sociological perceptions within the academic community. Moreover, by visualizing the variations in topic prevalence over time, it was possible to track the rise or decline of the major interest categories and topics. Finally, results also show how topics related to male philosophers garner greater attention throughout the corpus and which topics are more or less influenced by gender
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