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The history of magic art by André Breton : connections between artistic working and spontaneity.
No full textEm 1957, três décadas após a criação do primeiro Manifesto Surrealista (1924), Breton publica L'Art Magique : Une Histoire de l'Art, obra na qual são retomados temas como o fascínio pelo mistério, pelo desconhecido e pelo maravilhoso. O livro consiste em um vasto levantamento de imagens, obras de arte e textos de autores que lidaram com o tema da magia em diversos campos do conhecimento, como o ocultismo, a antropologia, a filosofia e a literatura. Nesta obra, Breton retoma temas tratados nos escritos surrealistas anteriores, tais como o acaso, a espontaneidade e a oposição ao racionalismo. Contudo, todos eles agora são reconfigurados a partir da perspectiva da magia. Isso fez com que o autor retomasse os textos de Baudelaire, o debate acerca da arte primitiva e a maneira como o surrealismo abordou a questão da magia. Tendo em vista que L'Art Magique é uma obra com muitas referências, optamos, neste trabalho, por fazer uma apresentação geral do texto e abordar as conexões entre o fazer artístico e a espontaneidade.In 1957, three decades after the creation of the first Surrealist Manifesto (1924), Breton published L'Art Magique : Une Histoire de l'Art. The book consists of a vast collection of images, works of art and texts by authors who use the theme of magic in various fields of knowledge, such as the occult, anthropology, philosophy and literature. The fundamental proposal of the work is to write an art history in a non-chronological sense. In that new context, Breton chose to revisit:Baudelaire’s texts, primitive art and surrealism's magic perspective. Considering that L'Art Magique is a work with many references, we separated that paper in two parts : the first one, we make a briefly presentation of all book; in the second, we address the connections between artistic making and spontaneity
Exploring the BSA- and DNA-binding, cytotoxicity, and cell cycle evaluation of ternary copper(ii)/diimine complexes withN,N-dibenzyl-N--benzoylthiourea as promising metallodrug candidates.
No full textFour new copper(II) complexes were synthesized and characterized with the general formula [Cu(N–N)(Th)(NO3)], where N–N corresponds to the N-heterocyclic ligands 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy), 4,7-diphenyl-1,10-phenanthroline (dpp), and 4,4-dimethyl-2,2′-bipyridine (dmbp) and Th represents the N,N-dibenzyl-N′-benzoylthiourea. Cytotoxic activities of the complexes against HCT116 (human colon carcinoma), HepG2 (human hepatocellular carcinoma), and non-tumor MRC-5 (human lung fibroblast) cells were investigated. The copper(II) complexes 1–4 were characterized by spectroscopic techniques while complexes 1 and 2 were studied using single-crystal X-ray diffraction as well. The complexes possessed a five-coordinated structure with one nitrate ligand as a monodentate at the axial position and two bidentate ligands N-heterocyclic and N,N-dibenzyl-N′-benzoylthiourea. The complexes showed promising IC50 values, ranging from 0.3 to 9.0 μM. Furthermore, interaction studies with biomolecules such as calf thymus DNA (ct-DNA) and Bovine Serum Albumin (BSA), which can act as possible biological targets of the complexes, were carried out. The studies suggested that the compounds interact moderately with ct-DNA and BSA. Complexes 1, 2, and 4 did not lead to cell accumulation at any stage of the cell cycle but caused a significant increase in internucleosomal DNA fragmentation. Whereas, compound 3 caused cell cycle arrest in the S phase while doxorubicin caused cell cycle arrest in the G2/M phase. The effect of structural modifications on the metal compounds was correlated with their biological properties and it was concluded that an increase in biological activity occurred with increasing the extension of the diimine ligands. Thus, complex 3 was the most promising one
A new approach to MacMahon’s Partition Analysis and associated applications.
No full textWe introduce a new elimination procedure for Partition Analysis to obtain generating functions free of Omega variables starting with a crude generating function containing or not factored polynomials. In contrast to Han’s approach (Ann Comb. 2003;7(4):467–480), we work with factored polynomials by judiciously constructing the quotient of a series modulo a certain prime ideal. Our results include diverse areas such as an Omega-based approach to compute the Hadamard product of power series and certain trigonometric integrals general- izing the main result of Kim (J Integer Seq. 2009;12:09.7.4) and recov- ering an integral identity of Boros and Moll (J Comput Appl Math. 1999;106(2):361–368), respectively. Furthermore, we construct a new Omega representation of analytic matrix functions which requires no spectral information and uses the matrix rank to simplify the calcula- tions. By specializing to tridiagonal matrices, the main result of Kiliç (Appl Math Comput. 2008;197(1):345–357) is obtained
Copper and zinc sulfides bioleaching by an extremely thermophilic archaeon in high NaCl concentration.
No full textChloride bioleaching has received attention of several mineral processing industries, particularly in countries where there is scarcity of freshwater and only chloride-containing waters can be used. Therefore, the present work investigated the effect of NaCl (1.0 mol L− 1 ) on the bioleaching of three sulfide minerals: chalcopyrite, bornite, and sphalerite by the thermophilic archaea Sulfolobus acidocaldarius. Chalcopyrite dissolution was only 25 % in the biotic experiment in the absence of chloride, but reached 90 % in the presence of both microor- ganisms and chloride, while less than 60 % extraction was observed in the abiotic experiment with chloride. In the experiments of bornite bioleaching, 86 % and 77 % of copper were extracted in the biotic and abiotic tests with chloride, respectively. In the absence of NaCl, the biotic and abiotic experiments presented similar copper dissolution (~35 %). Finally, bioleaching experiments carried out with sphalerite showed zinc extractions below 35 % in all conditions tested. The main contribution from the archaea was its ability to produce low concen- trations of ferric ion, which was partially precipitated as jarosite, resulting in low redox potential values (< 450 mV vs. Ag/AgCl), and efficiently bioleached bornite and chalcopyrite. Furthermore, XRD and SEM-EDS analyses demonstrated that sphalerite was practically not leached while bornite was transformed into new copper sulfide phases (CuS and Cu3FeS4). Jarosite and elemental sulfur were products of chalcopyrite and bornite bioleaching in the presence of chloride
Avaliação da atividade leishmanicida do extrato bruto e frações de folhas e flores obtidas a partir da Melaleuca leucadendra (L.) L..
No full textPrograma de Pós-Graduação em Biotecnologia. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa de Pós Graduação, Universidade Federal de Ouro Preto.A Leishmaniose Visceral (LV) é uma doença parasitária causada pelo protozoário Leishmania infantum e representa um grave problema de saúde pública tanto no Brasil quanto no resto do mundo. Nesse sentido, o Programa de Vigilância e Controle da Leishmaniose Visceral (PVC- LV) implementou medidas que incluem diagnóstico e tratamento dos casos, além de controle vetorial. No entanto, a quimioterapia para leishmanioses frequentemente envolve o uso de fármacos associados a efeitos adversos significativos, e regimes de tratamento prolongados que nem sempre são eficazes, com relatos de casos de resistência do parasito aos fármacos empregados. Neste contexto, a busca por novas abordagens terapêuticas é crucial, e a espécie vegetal Melaleuca leucadendra tem sido descrita por suas potencialidades biológicas, incluindo atividade leishmanicida. O presente estudo avaliou in vitro os extratos e frações das folhas e flores de M. leucadendra quanto à atividade leishmanicida contra L. infantum. Inicialmente, foram obtidos o extrato etanólico bruto (EB) e as frações hexânica (HE), acetatoetilênica (AE), diclorometânica (DM) e butanólica (BUT) das folhas e flores de M. leucadendra. A citotoxicidade dos extratos e frações foi avaliada em macrófagos murinos RAW 264.7, em que utilizando a Sulforodamina B (SRB) observamos maior citotoxicidade no EB e nas frações das folhas. A atividade leishmanicida foi avaliada em formas promastigotas de L. infantum utilizando o ensaio MTT e observou-se uma inibição mais pronunciada no EB e nas frações das folhas. O índice de seletividade (IS) revelou que a fração DM das folhas (6,62) e o EB das folhas (6,4) apresentaram índices altos, enquanto nas flores, a fração DM destacou-se com um índice de 14,25. A atividade leishmanicida em formas amastigotas de L. infantum GFP, utilizando citometria de fluxo, demonstrou que a fração DM das folhas e flores, bem como a fração BUT das folhas, foi capaz de reduzir, a níveis comparáveis à Anf-B, o percentual de macrófagos infectados em relação ao controle infectado (CI). Além disso, o EB e AE das folhas, juntamente com as frações HE das flores e DM e BUT das folhas e flores, reduziram a carga parasitária (intensidade de fluorescência) nos macrófagos. Os resultados in vitro demonstram baixa citotoxicidade e atividade leishmanicida tanto contra formas promastigotas quanto amastigotas de L. infantum, especialmente para a fração DM das folhas e flores. Esses achados sugerem um potencial nessas frações para o isolamento de novos compostos, além do desenvolvimento de novos agentes terapêuticos contra a LV.Visceral Leishmaniasis (VL) is a parasitic disease caused by the protozoan Leishmania infantum and represents a serious public health issue both in Brazil and worldwide. In this context, the Visceral Leishmaniasis Surveillance and Control Program (PVC-LV) has implemented measures including diagnosis and treatment of cases, as well as vector control. However, chemotherapy for leishmaniasis often involves the use of drugs associated with significant side effects, and prolonged treatment regimens that are not always effective, with reports of resistance of the parasite to the drugs used. In this scenario, the search for new therapeutic approaches is crucial, and the plant species Melaleuca leucadendra has been described for its biological potential, including leishmanicidal activity. This study evaluated in vitro the extracts and fractions of M. leucadendra leaves and flowers for leishmanicidal activity against L. infantum. Initially, the crude ethanolic extract (EB) and the hexane (HE), ethyl acetate (EA), dichloromethane (DM), and butanol (BUT) fractions from the leaves and flowers of M. leucadendra were obtained. The cytotoxicity of the extracts and fractions was assessed in murine macrophages RAW 264.7, where using Sulforhodamine B (SRB), higher cytotoxicity was observed in the EB and the leaf fractions. Leishmanicidal activity was evaluated in L. infantum promastigote forms using the MTT assay, and more pronounced inhibition was observed in the EB and the leaf fractions. The Selectivity Index (SI) revealed that the DM fraction of the leaves (6.62) and the EB of the leaves (6.4) had high indices, while in the flowers, the DM fraction stood out with an index of 14.25. Leishmanicidal activity in L. infantum GFP amastigote forms, using flow cytometry, showed that the DM fraction of the leaves and flowers, as well as the BUT fraction of the leaves, was capable of reducing, to levels comparable to Amphotericin B, the percentage of infected macrophages relative to the infected control (IC). Additionally, the EB and AE of the leaves, along with the HE fraction of the flowers and DM and BUT fractions of the leaves and flowers, reduced the parasitic load (fluorescence intensity) in the macrophages. The in vitro results demonstrate low cytotoxicity and leishmanicidal activity against both promastigote and amastigote forms of L. infantum, especially for the DM fraction of the leaves and flowers. These findings suggest a potential in these fractions for the isolation of new compounds and the development of new therapeutic agents against VL
Parental participation in Latin American basic education : a systematic review.
No full textExiste consenso entre los investigadores acerca de los beneficios de la participación parental en la educación escolar primaria. El desarrollo empírico disponible remite a investigaciones centralmente desarrolladas en los países del hemisferio norte donde las desigualdades educativas son menos visibles que en los países latinoamericanos. Cuando se la integra, esta no es abordada de forma diferenciada, lo cual limita el conocimiento sobre las especificidades y comunalidades entre sus países. El objetivo de esta investigación es analizar la producción científica latinoamericana que aborda el estudio de la participación parental en el campo de la educación escolar primaria, publicada entre los años 2019 y año 2024, siguiendo los lineamientos metodológicos de las revisiones sistemáticas. La revisión destaca la escasa y desigual producción entre los países donde priman los estudios sobre involucramiento parental desde un enfoque pedagógico y formativo. Siguiendo lo que se ha descrito para el caso español y los países anglófonos la revisión muestra el uso de conceptos diferentes para referirse a la participación parental. Las escasas definiciones encontradas muestran distinciones entre las nociones de involucramiento, implicación, conexión entre familias-escuela y participación parental, lo que muestra un desarrollo conceptual novedoso respecto a lo que se encuentra en los países del norte.There is consensus among researchers about the benefits of parental involvement in primary school education. The empirical development available refers to research mainly developed in the countries of the northern hemisphere where educational inequalities are less visible than in Latin American countries. When it is integrated, it is not addressed in a differentiated way, which limits knowledge about the specificities and commonalities between its countries. The objective of this research is to analyze the Latin American scientific production that addresses the study of parental involvement in the field of primary school education, published between 2020 to 2024, following the methodological guidelines of Systematic Reviews. The review highlights the scarce and unequal production between countries where studies on parental involvement from a pedagogical and formative approach prevail. Following what has been described for the Spanish case and the Anglophone countries, the review shows the use of different concepts to refer to parental involvement. The few definitions found show distinctions between the notions of involvement, implication, connection between families and schools and parental participation, which shows a novel conceptual development compared to what is found in northern countries
Cascade proportional–integral control design and affordable instrumentation system for enhanced performance of electrolytic dry cells.
No full textIn this paper, we present a cost-effective system for monitoring and controlling alkaline electrolyzers, intending to improve hydrogen gas production on a laboratory scale. Our work includes two main innovations. Firstly, we suggest an approach to calibrate a standard air flow meter to accurately measure the flow of hydrogen-rich gas from electrolyzers, improving measurement accuracy while keeping costs low. Secondly, we introduce a unique cascade control method to manage hydrogen-rich gas production in the electrolyzer, ensuring precise control over gas flow rates. By combining affordable, energy-efficient devices with a PI control system, we achieve efficient gas production through electrolysis, replacing manual control approaches. Experimental results confirm the effectiveness of our cascade control method, demonstrating stable operation with minimal errors. These results provide a foundation for further research into control strategies to enhance the performance of electrolytic cells
Otimização de briquetes produzidos a partir de resíduos finos do processo produtivo de ferroligas de manganês.
No full textPrograma de Pós-Graduação em Engenharia Mineral. Departamento de Engenharia de Minas, Escola de Minas, Universidade Federal de Ouro Preto.Matérias-primas finas não podem ser alimentadas nos fornos elétricos de redução utilizados na fabricação de ferroligas de manganês, uma vez que impactam na permeabilidade do leito. Diante disso, técnicas de aglomeração podem ser empregadas para minimizar os impactos ambientais e econômicos que a estocagem desse material demanda. Neste sentido, a briquetagem se apresenta como uma técnica vantajosa uma vez que permite a união de partículas sem a necessidade de utilização de altas temperaturas, além de ser versátil sob o ponto de vista granulométrico. Este trabalho teve como objetivo elaborar briquetes com finos de duas tipologias de minério de manganês: silicatada e oxidada, com adição de pó de despoeiramento do britador da liga de FeSiMn, moinha de carvão vegetal, bem como três diferentes aglomerantes: bentonita, amido pré-gelatinizado e cal hidratada + melaço. Inicialmente, foi realizada a caracterização química, física e mineralógica das matérias-primas utilizadas na elaboração dos briquetes. Em seguida, a resistência à compressão dos briquetes foi otimizada, considerando as variáveis independentes (i) pressão de compactação, (ii) tempo de cura e (iii) % em peso de aglomerante, por meio de planejamentos experimentais multivariados, em que consistiu inicialmente de um estudo de triagem usando planejamento fatorial completo 23 , posteriormente, foi utilizada a Metodologia de Superfície de Resposta (MSR), por planejamento composto central esférico. Os resultados foram avaliados por meio da análise de variância e um modelo de regressão foi estabelecido. A partir das condições otimizadas de briquetagem, foram realizados ensaios adicionais de resistência mecânica, porosidade e absorção de água nos briquetes e nos minérios granulados, para fins comparativos. Ensaios metalúrgicos de crepitação, degradação sob redução e redutibilidade foram conduzidos tanto para os briquetes nas condições otimizadas quanto para os minérios granulados. Por fim, uma caracterização microestrutural dos briquetes foi realizada antes e após os ensaios de redutibilidade. Para os aglomerados com finos de minérios silicatados de manganês, o estudo constatou que briquetes com bentonita exibiram uma resistência à compressão otimizada prevista (RCP) de 4,02MPa, alcançada com uma pressão de compactação de 67,55MPa, tempo de cura de 11 dias e 12,71% de bentonita. Para briquetes com amido pré- gelatinizado, obteve-se RCP de 7,04MPa com uma pressão de compactação de 67,52MPa, um tempo de cura de 19,51 dias e 8,07% de amido pré-gelatinizado. Para briquetes aglomerados usando cal hidratada + melaço, uma pressão de compactação de 27,09MPa e um tempo de cura de 23,27 dias resultaram em RCP de 1,63MPa. Com relação aos aglomerados contendo o fino de minério de manganês oxidado, o estudo demonstrou que os briquetes com bentonita apresentaram uma RCP otimizada de 2,54MPa, com um tempo de cura de 11 dias e 11,5% de bentonita. Os briquetes com cal hidratada + melaço obtiveram uma RCP de 3,70MPa, com uma pressão de compactação de 62,12MPa, um tempo de cura de 24 dias e uma adição de 16,2% de cal hidratada + melaço. Briquetes com aglomerantes orgânicos exibiram maiores valores de crepitação e índice de degradação por redução. Para todas as composições de briquetes, o índice de redutibilidade foi superior ao dos minérios granulados. Após os testes de redutibilidade, briquetes com finos de minério oxidado apresentaram maior quantidade de manganosita, em comparação com os briquetes de finos silicatados. Além disso, transformações de fase nos constituintes dos briquetes foram observadas durante o processo de redução. Os resultados indicaram a viabilidade dos briquetes como substitutos para minérios granulados em fornos elétricos de redução, especialmente os briquetes aglomerados com bentonita, em comparação com aqueles feitos com cal hidratada + melaço e amido pré-gelatinizado, independentemente do tipo de finos de minério de manganês utilizado. Dessa forma, o estudo permitiu avaliar o uso dos briquetes como potencial substituto dos minérios granulados, trazendo benefícios em termos de eficiência e sustentabilidade.Fine raw materials cannot be fed into the electric reduction furnaces used in the production of manganese ferroalloys, as they impact on bed permeability. Therefore, agglomeration techniques can be employed to minimize the environmental and economic impacts of storing this material. In this context, briquetting presents itself as an advantageous technique since it allows the bonding of particles without the need for high temperatures, and it is versatile from a granulometric standpoint. This work aimed to produce briquettes using fines from two types of manganese ore: silicated and oxidized, along with dust from FeSiMn alloy crusher, charcoal fines, and three different binders: bentonite, pregelatinized starch, and slaked lime + molasses. Initially, the chemical, physical, and mineralogical characterization of the raw materials used in the briquette production was carried out. Next, the compressive strength of the briquettes was optimized by considering the independent variables: (i) compaction pressure, (ii) curing time, and (iii) binder weight percentage, through multivariate experimental designs. It initially consisted of a screening study using a full factorial 23 design, followed by the application of Response Surface Methodology (RSM) with a central composite design. The results were evaluated through analysis of variance and a regression model was established. Based on the optimized briquetting conditions, additional tests were conducted to assess the mechanical strength, porosity, and water absorption of the briquettes and lump ores for comparative purposes. Metallurgical tests for decrepitation, reduction degradation, and reducibility were also performed on both the optimized briquettes and the lump ores. Finally, a microstructural characterization of the briquettes was carried out before and after the reducibility tests. For the briquettes made with silicate manganese ore fines, the study found that briquettes with bentonite exhibited an optimized predicted compressive strength (PCS) of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa, a curing time of 11 days, and 12.71% bentonite. For briquettes with pre-gelatinized starch, a PCS of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pre-gelatinized starch. For briquettes agglomerated using slaked lime + molasses, a compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a PCS of 1.63 MPa. Regarding the briquettes containing oxidized manganese ore fines, the study demonstrated that briquettes with bentonite exhibited an optimized PCS of 2.54 MPa, with a curing time of 11 days and 11.5% bentonite. Briquettes with slaked lime + molasses achieved a PCS of 3.70 MPa, with a compaction pressure of 62.12 MPa, a curing time of 24 days, and an addition of 16.2% slaked lime + molasses. Briquettes with organic binders exhibited higher values of decrepitation and reduction degradation index. For all briquette compositions, the reducibility index was higher than that of lump ores. After the reducibility tests, briquettes with oxidized ore fines presented a higher amount of manganosite compared to briquettes with silicated fines. Additionally, phase transformations in the briquette constituents were observed during the reduction process. The results indicated the feasibility of briquettes as substitutes for lump ores in electric reduction furnaces, especially briquettes agglomerated with bentonite, compared to those made with slaked lime + molasses and pre- gelatinized starch, regardless of the type of manganese ore fines used. Thus, the study enabled the evaluation of briquettes as a potential substitute to lump ores, offering benefits in terms of efficiency and sustainability
Provenance of volcano-sedimentary features using tourmaline and REE compositional analysis, in the Paraná Basin, southern Brazil.
No full textThe present research focuses on sediments’ compositional analysis, in the Paraná Basin, to demonstrate provenance contributions for the volcano-sedimentary features distributed along three regions of the Basin’s border. In this context, the analyzed sediments, which are generally attributed to the Botucatu Formation, interact with volcanic lava flows from the Serra Geral Formation, establishing a volcano-sedimentary interaction. Nonetheless, the classic description for the Botucatu Formation comprehends almost ubiquitous fine to medium sandstones, while the herein sedimentary rocks vary from fine-grained to very coarse sediments. The granulometry difference raises questions about unexplained events during the Cretaceous volcanism (Serra Geral Formation) over the Botucatu desert. Accordingly, the studied area is distributed into regions A, B, and C from the center to the eastern of the state respectively, covering the Paraná basin’s border where the volcano-sedimentary rocks can be outcropped. The methodologies employed involve the analysis of tourmaline compositions and REE patterns. These analytical tools help identify provenance variations and the development of local processes. As a result, the data indicate the predominance of meta-pelites and metapsammites in region A, while in region C there is a prevalence of granitoids contribution, while region B is a transition area showing contributions of both meta-pelites, metapsammites, and granitoids that are attributed to some units of the Sul-Rio-Grandense Shield
Exploring tailings dam stability considering uncertainties in the critical state parameters of the NorSand Model.
No full textStability analyses of tailings dams often utilize advanced constitutive models that require the calibration of many parameters. Yet, there remains limited research on the implications of parameter uncertainties within these constitutive models on the safety factor of tailings dams. This study successfully investigated the impact of uncertainty in critical state parameters of the NorSand model on the stability of a tailings dam. To achieve this goal, feld and laboratory tests characterized the materials constituting the geotechnical profle of the dam, involving residual shale soils, alluvial soils, and granular-textured tailings. These tests were included in the fnite element (FE) program PLAXIS 2D to estimate several parameters of the constitutive models that characterized the materials of the dam: Hardening Soil, Mohr–Coulomb, and NorSand. Monte Carlo simulations of FE analyses were conducted considering the construction period of the dam spanning 2500 days. Furthermore, the critical state line (CSL) parameters employed within the NorSand model were reconciled with void ratio data for the uncompacted tailings utilizing a Bayesian framework. The Bayesian framework allowed us to investigate: (i) the statistical distribution of the critical state parameters, (ii) confdence intervals for horizontal and vertical displacements, (iii) shear strains at various monitoring points across the tailings dam, (iv) and the marginal distribution of the factor of safety. The fndings reveal a strong correlation between the three CSL parameters, which presented poorly defned statistical distributions. Nonetheless, the power law equation used to model the CSL closely matches laboratory data from triaxial tests (R2=0.97). Uncertainties in the CSL, especially at lower stress levels, contribute to settlement prediction uncertainties. Monitoring points at the structure’s base showed strains that could induce downstream slope instability and potential liquefaction failure. The histogram of the safety factors remained narrow, normally distributed, ranging from 1.39 to 1.47. This work is important because it explicitly addresses the uncertainty in the critical state parameters of the Nor-Sand model within geotechnical analysis