Resumo Nanofibras de CaFe2O4 foram sintetizadas com sucesso via solution blow spinning (SBS) e as influências do tratamento térmico nas propriedades morfológicas, microestruturais, magnéticas e óticas das nanofibras foram avaliadas. No processo de síntese, quantidades estequiométricas de nitratos de ferro e cálcio foram dissolvidos em solução aquosa contendo polivinilpirrolidona (PVP) e, em seguida, nanofibras híbridas (PVP/precursores) foram produzidas por SBS. As nanofibras híbridas foram calcinadas e depois submetidas às caracterizações microestrutural, morfológica e magnética. Os resultados evidenciaram que as nanofibras apresentaram natureza cristalina de fase única CaFe2O4, com tamanho de cristalito de 31,7 e 34,4 nm para as amostras calcinadas a 800 e 1000 °C, respectivamente. As fibras de CaFe2O4 calcinadas a 600 e 800 °C apresentaram morfologia homogênea, sem beads e com diâmetros médios de 521 e 427 nm, respectivamente. Os resultados também revelaram nanofibras com baixos gaps de energia de aproximadamente 1,98 eV e características de materiais magnéticos macios.

Abstract CaFe2O4 nanofibers were successfully synthesized via solution blow spinning (SBS), and the influences of heat-treatment on morphological, microstructural, magnetic, and optical properties of the nanofibers were evaluated. In the synthesis process, stoichiometric amounts of iron and calcium nitrates were dissolved in an aqueous solution containing polyvinylpyrrolidone (PVP) and, after that, hybrid nanofibers (PVP/precursors) were produced by SBS. The hybrid nanofibers were calcined and then subjected to microstructural, morphological, and magnetic characterizations. The results evidenced that the fibers presented the crystalline nature of the single-phase CaFe2O4, with a crystallite size of 32.7 and 34.4 nm for the samples calcined at 800 and 1000 °C, respectively. The CaFe2O4 fibers calcined at 600 and 800 °C presented a homogeneous morphology, without beads, and mean diameters of 521 and 427 nm, respectively. The results also revealed nanofibers with low band gaps of approximately 1.98 eV and characteristics of soft magnetic materials.

Resumo Neste trabalho foram propostos obter e caracterizar o Fe3O4 e o CoFe2O4 associados ao tetraetilortossilicato (TEOS) e do 3-aminopropiltrimetoxissilano (APTS), visando avaliar o efeito da modificação de superfície das partículas magnéticas sobre as propriedades estrutural, morfológica e magnéticas para aplicação como carreador de fármaco. As amostras foram caracterizadas por difração de raios X, espectroscopia no infravermelho com transformada de Fourier, análise textural, microscopia eletrônica de varredura e medidas magnéticas. A partir dos resultados observou-se que o Fe3O4 e o CoFe2O4 foram sintetizados com sucesso. A presença da fase principal do Fe3O4 foi notada no sistema obtido com o Fe3O4/SiO2 e CoFe2O4 no sistema obtido com o CoFe2O4/SiO2. A formação dos híbridos (core-shell) foi confirmada pela presença de bandas características da sílica. Os sistemas obtidos com o Fe3O4 apresentaram diâmetros de partícula superiores aos formados com o CoFe2O4, ambos formados de aglomerados de tamanho e formato irregulares e com comportamento típico de materiais ferrimagnéticos.

Abstract In this work, the obtention and characterization of Fe3O4 and CoFe2O4 associated to tetraethyl orthosilicate (TEOS) and 3-aminopropyltrimethoxysilane (APTS) were proposed, aiming to evaluate the effect of surface modification of magnetic particles on structural, morphological and magnetic properties for application as a drug carrier. The samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, textural analysis, scanning electron microscopy and magnetic measurements. The results showed that Fe3O4 and CoFe2O4 were synthesized successfully. The presence of the Fe3O4 main phase was observed in the system obtained with Fe3O4/SiO2 and CoFe2O4 in the system obtained with CoFe2O4/SiO2. The formation of hybrids (core-shell) was confirmed by the presence of characteristic bands of silica. The systems obtained with Fe3O4 had larger particle diameters than those formed with CoFe2O4, both formed by agglomerates of irregular size and shape and with typical behavior of ferrimagnetic materials.

Resumo O ferroespinélio Ni0,7Zn0,3Fe2O4 foi sintetizado por reação de combustão e seu desempenho catalítico na reação de esterificação metílica e etílica do óleo de soja foi investigado. As amostras foram caracterizadas por difração de raios X, análise de refinamento, espectroscopia de fluorescência de raios X por energia dispersiva, espectroscopia no infravermelho com transformada de Fourier, análise textural, microscopia eletrônica de varredura, densidade por picnometria de hélio, análise granulométrica, análise termogravimétrica, medidas magnéticas e testes catalíticos. A síntese foi eficiente obtendo o ferroespinélio com fase única Ni0,7Zn0,3Fe2O4, com tamanho de cristalito de 20 nm, elevada área superficial (86 m2/g) e magnetização de saturação de 18 emu/g. O ferroespinélio possibilitou atividade catalítica promissora em ambas as condições reacionais estudadas, sendo mais ativo na conversão do óleo de soja em biodiesel na esterificação metílica apresentando conversão média de 93,9±2,8%.

Abstract Ni0.7Zn0.3Fe2O4 ferrospinel was synthesized by combustion and its catalytic performance in methyl and ethyl esterification of the soybean oil was investigated. The samples were characterized by X-ray diffraction, Rietveld refinement analysis, energy dispersive X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy, textural analysis, scanning electron microscopy, density by picnometry, particle size analysis, thermogravimetric analysis, magnetic measurements, and catalytic tests. The synthesis was efficient resulting in a ferrospinel with single phase Ni0.7Zn0.3Fe2O4 with crystallite size of 20 nm, high surface area (86 m2/g) and saturation magnetization of 18 emu/g. The ferrospinel had promising catalytic activity in both reaction conditions studied, being more active in the conversion of soybean oil to biodiesel in methyl esterification with an average conversion of 93.9±2.8%.

Resumo O objetivo deste trabalho foi investigar as propriedades magnéticas e a dependência da condutividade elétrica com a temperatura associada ao modelo de barreiras de potencial entre os cristalitos. A cerâmica de espinélio de gálio e magnésio possui baixa coercividade magnética e alta resistividade elétrica. As amostras de MgGa2-xFexO4 (x= 0,01, 0,05, 0,15, 0,25, 0,35) foram preparadas pelo método de estado sólido e sinterizada a 800 °C durante 8 h. A análise de difração de raio X confirmou a formação de única fase com estrutura de espinélio cúbico compacto. As medições magnéticas mostraram que a magnetização de saturação e remanescência de todas as amostras aumentaram com a concentração de ferro. O campo coercitivo diminuiu até a concentração x= 0,15 e acima de x= 0,25 observou-se um aumento no campo coercivo. Através da caracterização eléctrica verificou-se que as amostras apresentaram comportamento isolante para x= 0,01 e acima de x= 0,15 observou-se um comportamento semicondutor compatível com o modelo de barreira de potencial entre cristalitos, ou seja, preenche a condição de L/2 > LD (tamanho de cristalito L em comparação com o comprimento de Debye) e a condução é limitada por barreiras de potencial entre os cristalitos.

Abstract The aim of this work was to investigate the magnetic properties and the electrical conductivity temperature dependence associated to the potential barrier between the crystallites model. Gallium and magnesium containing spinel ceramic has low magnetic coercivity and high electrical resistivity. MgGa2-xFexO4 samples (x= 0.01, 0.05, 0.15, 0.25, 0.35) were prepared by solid-state method and sintered at 800 °C for 8 h. X-ray diffraction analysis confirmed the formation of a single phase with compact cubic spinel structure. The magnetic measurements show that the saturation magnetization and remanence of all samples increased with increasing iron concentration. The coercive field decreased up to the concentration x= 0.15, and above x= 0.25 it was observed an increase in the coercive field. Through electrical characterization it was found that the samples presented highly insulating behavior for x= 0.01, and further increase in x above 0.15 gives a semiconductor behavior compatible with the potential barrier between the crystallites model, i.e. fulfills the condition L/2 > LD (crystallite size L in comparison with the Debye length LD), and the conduction is limited by potential barriers between the crystallites.

Abstract The automotive industry is increasingly using adhesive joints bonding advanced lightweight materials to reduce vehicle weight. Strength under impact loadings is a major concern for this application and mixed adhesive joints can effectively improve the joints by combining stiffness and flexibility on the same overlap. This work introduces and studies several configurations for static and impact tests of mixed adhesive joints with four adhesives in different combinations. The main purpose of this work is the development of a strong adhesive joint using a mixed adhesive layer and perform a series of mechanical to study its mechanical behaviour. It is concluded that the use of the mixed adhesive technique improves both static and impact strength by introducing flexibility to the joint which subsequently allows more energy absorption when introduced in crash resistant structures.

Resumo Os objetivos deste trabalho foram a obtenção de uma ferrita de chumbo e cobre com a estrutura do espinélio, a caracterização da sua microestrutura e a determinação das suas propriedades magnéticas. A ferrita de cobre e chumbo é um material com baixa coercividade magnética, alta resistividade elétrica e alta permeabilidade magnética. Amostras com estequiometria PbxCu1-xFe2O4, com (x= 0, 0,1 e 0,2), foram produzidas pelo processo de metalurgia do pó e sinterizadas a 800 °C por 6 h em atmosfera ambiente. As caracterizações estrutural, microestrutural e magnética foram realizadas utilizando as técnicas de difração de raios X, microscopia eletrônica de varredura, magnetômetro de amostra vibrante e análise termogravimétrica magnética. Os resultados mostram que as amostras são formadas exclusivamente pela estrutura do espinélio tetragonal. As curvas de histerese mostram características de materiais magnéticos moles e sua magnetização de saturação aumentou com a concentração de chumbo. O valor da temperatura de Curie diminuiu com o aumento da concentração de chumbo.

Abstract The objectives of this work were to obtain a lead and copper ferrite with spinel structure, characterizing the microstructure and the determination of their magnetic properties. The copper and lead ferrite is a material with low magnetic coercivity, high electrical resistivity and high magnetic permeability. Samples with stoichiometry PbxCu1-xFe2O4 with (x = 0, 0.1, and 0.2) were prepared by powder metallurgy process and sintered at 800 ºC for 6 h in air. The structural, microstructural and magnetic characterizations were performed using the techniques of X-ray diffraction, scanning electron microscopy, vibrating sample magnetometer, and magnetic thermal gravimetric analysis. The results showed that samples are formed exclusively by the tetragonal spinel structure. Hysteresis loops show the characteristics of a soft magnetic material and the saturation magnetization increased with the lead concentration. The value of the Curie temperature decreased with increasing lead concentration.

ResumoFerritas Ni-Co são cerâmicas magnetostritivas que possuem potencial de aplicação em sensores magnetostrictivos/ magnetoelásticos, bem como em compósitos magnetoelétricos. Ferritas espinélio do tipo Ni-Co com alto teor de Ni foram processadas por meio do método cerâmico e amostras foram sinterizadas no estado sólido a 1350 ºC e via fase líquida a 950 ºC com adição de Bi2O3. As amostras sinterizadas foram caracterizadas por meio de microscopia óptica, microscopia eletrônica de varredura, espectroscopia Raman, magnetometria de amostra vibrante e dilatometria de capacitância. Utilizando-se pequenas adições de Bi2O3, na proporção de 0,6% molar, foi possível sinterizar a ferrita Ni-Co a 950 ºC, obtendo-se amostras de alta densidade relativa; no entanto, estas amostras sinterizadas via fase líquida apresentaram partículas de óxido de ferro na microestrutura. As amostras produzidas apresentaram sensibilidade magnetoelástica próxima à da esperada para CoFe2O4, com histerese magnética significativamente menor. Os resultados obtidos indicam que as propriedades magnéticas das amostras analisadas são adequadas para aplicações em sensores magnetomecânicos.

AbstractNi-Co ferrites are magnetostrictive ceramics that have potential application in magnetostrictive/ magnetoelastic sensors, as well as in magnetoelectric composites. Ni-rich Ni-Co spinel ferrite samples were processed by the ceramic method and bulk samples were sintered at 1350 ºC in the solid state and at 950 ºC with Bi2O3 liquid phase. The sintered samples were characterized by light microscopy, scanning electron microscopy, Raman spectroscopy, vibrating sample magnetometry and capacitance dilatometry. With Bi2O3 additions as small as 0.6 mol% it was possible to sinter the Ni-Co ferrite at 950 ºC, obtaining high-density samples; however, such liquid-phase sintered samples presented iron oxide particles. The studied samples presented magnetoelastic sensitivities very close to CoFe2O4, with significantly lower magnetic hysteresis. The results thus indicate that the magnetic properties of the samples analyzed are suitable for applications in magnetomechanical sensors.

Atualmente há uma crescente demanda no cenário mundial com relação ao tratamento de resíduos industriais, dentre estes o fenol e pilhas inutilizadas. Óxidos e cerâmicas a base de ferro, tais como ferritas são utilizadas como catalisadores no processo Fenton heterogêneo. Os processos de Fenton e foto-Fenton apresentam alta eficiência no tratamento de resíduos tóxicos utilizando catalisadores a base de ferro. Neste contexto foram desenvolvidas ferritas a partir de resíduos de pilhas inutilizadas. O uso destas ferritas como catalisadores é bastante interessante, uma vez que, são materiais ferromagnéticos podendo ser recuperados no final do processo utilizando campo magnético, evitando a liberação de Fe2+ e Fe3+ no efluente. Os resultados mostraram que a ferrita proveniente de pilhas inutilizadas e calcinada à temperatura de 500 °C apresentou estrutura correspondente a fase espinélio e magnéticas (M S= 37,04 emu.g-1) e como catalisador de fotodegradação atingiu-se 90% de remoção de fenol em pH 2,5 durante 2 h de irradiação.

Currently there is a growing global demand with respect to industrial waste treatment, among them phenol and spent batteries. Iron oxides and ceramics containing iron, such as ferrites, have been used with success as catalysts for heterogeneous Fenton process. The Fenton and photo-Fenton processes have high efficiency in treatment of toxic residue using iron as catalysts. In this respect, ferrites were developed from spent batteries. The use of these ferrites as catalysts is very interesting because these oxides are ferromagnetic and can be recovered at the end of the process using a magnetic field, avoiding the discharge of Fe2+ and Fe3+ in the environment. The results showed that the ferrite from spent batteries calcined at 500 °C presents structural of spinel phase and magnetic properties (Ms= 37.04 emu.g-1) and applied in photo-Fenton process, it was reached 90% of phenol removal at pH 2.5 with 2 h of irradiation.

Flagellin is the structural protein and most abundant component of bacterial flagella. The flagellum filament contains around 20,000 - 100,000 subunits of 50 kDa flagellin that can have diverse biotechnological applications such as vaccine adjuvant and cellular protector during chemo- and radiotherapy. The main aim of this work was to study a production process of purified native FliC flagellin of Salmonella Typhimurium. The culture conditions in shakers were established with medium devoid of animal-derived components. In bioreactors, culture conditions were established in order to obtain flagellin from the culture supernatant by tangential ultrafiltration (TUF). The concentrated 750 kDa cut-off TUF fraction had a purification factor of 1.5 and a recovery yield of 52.2% for flagellin. The volumetric production of flagellin using the described procedure achieved around 307 mg/L of culture, which represented a significant improvement over previously reported methods. These results permit the development of production and purification processes that can be easily scaled up.

The rough grind machine operation in metallic material produce a sub product with the followings components such as: metallic residue, small parts come from the resin grinds, diatomaceous earth material (filter material) and soluble oil in water for tools cooling. According [HU1UH] from ABNT, this sub product is toxic, not inert material, aggress the environment with pollution in the currency water and contaminate the ground when incorrectly go to the municipal solid waste. The final destination of this sub product, is the incineration, in the cements company, being the incorporated the sub product to the cement, during your production. With the qualitative result using the scanning electron microscopy (SEM), coupled to the dispersive energy spectroscopy (EDS), two experiments were made with objective to separate the magnetic material of the non-magnetic material, using a permanent magnet. We conclude that the magnetic material can be used by powder metallurgy process in production of pieces.

Durante o curso da gastrite crónica, os alelos IL1B -511T, IL1RN +2018C e o haplótipoTNFA-308A/-238A estão associados ao aumento dos níveis de produção das respectivas citocinas. Os indivíduos portadores destes polimorfismos podem apresentar um aumento da produção de citocinas próinflamatórias, condicionando uma inflamação severa e constante, atrofia da mucosa gástrica, hipocloridria e, por fim, desenvolvimento de carcinoma gástrico devido a alterações genéticas das células epiteliais que, na tentativa de adaptação, sofrem fenómenos de metaplasia e displasia. Pretendeu-se verificar a presença dos polimorfismos das citocinas pro-inflamatórias IL-1ß, IL-1RN e TNF-α no carcinoma gástrico e na gastrite crónica. Os polimorfismos IL1B -511C>T, IL1RN +2018T>C e TNFA -308G>A e -208G>A foram analisados por ARMSPCR em 47 biopsias: 36 biopsias de carcinoma gástrico, 11 biopsias de Gastrite crónica com infecção moderada por Helicobacter pylori e 39 amostras de sangue de indivíduos saudáveis, usando o Cytokine Box Typing Kit (Genebox R&D, Coimbra, Portugal). Foi encontrada associação entre o genótipo IL1RN +2018 CC (p=0.0002) e o carcinoma gástrico, sendo o genótipo IL1RN +2018 TT (p=0.01) associado com a ausência de doença. Os genótipos IL1RN +2018 CC (p=0.01), TNFA - 308 AA, alto produtor, (p=0.006) e o TNFA -238 AA, alto produtor, (p=0.0001) foram associados com a susceptibilidade à gastrite crónica, enquanto os genótipos TNFA -308 GG e TNFA-238 GG, baixos produtores, demonstraram um efeito protector. Concluímos que os genótipos, altos produtores, do TNFA e IL1RN, têm um papel importante na manutenção da gastrite crónica e estão presentes no carcinoma gástrico, podendo o estudo dos polimorfismos destes genes ser um importante marcador para a susceptibilidade individual para o desenvolvimento do carcinoma na gastrite crónica.

In chronic gastritis the alleles IL1B -511T, IL1RN +2018C and the haplotype TNFA -308A/-238A are associated with high levels of the respective cytokine production. The referred polymorphisms may also induce a high production of pro-inflammatory cytokines leading to a constant and severe inflammatory response and subsequently, gastric mucosa atrophy, hypochloridria and finally gastric carcinoma as a consequence of genetic alterations in epithelial cells after metaplastic and dysplastic phenomena. The presence of those polymorphisms representing the proinflammatory cytokines IL-1ß, IL-1RN and TNF-α were analysed in cases of chronic gastritis and gastric carcinoma. The polymorphisms IL1B -511C>T, IL1RN +2018T>C and TNFA -308G>A and -208G>A were analysed by ARMSPCR in 47 biopsies: 36 cases of gastric carcinoma, 11 cases of chronic gastritis associated with Helicobacter pylori were studied; 39 blood samples of healthy individuals were also analysed with the Cytokine Box Typing Kit (Genebox R&D, Coimbra, Portugal). An association between the IL-1RN +2018 CC genotype and gastric carcinoma was observed (p=0.0002), while the genotype IL-1RN +2018 TT (p=0.01) was associated with disease absence. The genotypes IL-1RN +2018 CC (p=0.01), TNFA -308 AA (p=0.05) and TNFA -238 AA (p=0.0001) were demonstrated in cases of chronic gastritis and the TNFA - 308 GG and TNFA -238 GG genotypes, low producers, were associated with gastritis resistance. In this study TNFA and IL1RN polymorphisms were associated with chronic gastritis due to Helicobacter pylori infection and were also present in patients with gastric carcinoma. Therefore, if these results are confirmed those polymorphisms may be used as a biological marker of individual susceptibility in the development of gastric carcinoma in chronic gastritis.

Os autores apresentam o caso clínico de doente do sexo feminino, 54 anos, raça branca, que recorreu ao médico assistente por dor abdominal associada a manifestações constitucionais. A ecografia revelou massa pancreática e formações nodulares hepáticas compatíveis com lesões secundárias, resultado posteriormente corroborado por tomografia computorizada, que acrescentou critérios de irressecabilidade, nomeadamente invasão dos vasos mesentéricos e do duodeno. A biopsia ecoguiada obteve material cujo estudo anatomopatológico revelou tratar-se de adenocarcinoma do pâncreas. Iniciou quimioterapia, verificando-se melhoria clínica progressiva. A reavaliação imagiológica, após 7 ciclos de tratamento, não detectou a lesão primitiva nem as lesões secundárias, sugerindo resposta completa. Foi mantido esquema regular de quimioterapia, persistindo a remissão 8 meses após a documentação da resposta completa.

The authors present a case study of a 54-year-old white female patient, who went to her regular physician complaining of abdominal pain and constitutional symptoms. An ultrasound revealed a pancreatic mass and hepatic nodular formations compatible with secondary lesions. This finds was subsequently confirmed by computed tomography, which revealed that the pancreatic tumor wasn't resectable due to invasion of the mesenteric vessels and the duodenum. Ultrasound guided biopsy obtained a sample which pathology revealed to be an adenocarcinoma of the pancreas. The patient was submitted to chemotherapy, showing progressive clinical improvement. Imaging reevaluation, after 7 cycles, detected neither the primary lesion nor the secondary lesions, suggesting a complete response. A regular chemotherapy plans was maintained, and the patient remains in remission after an 8 months follow up period.

Observando a literatura pode ser verificado um crescente número de trabalhos que determinam potenciais contaminantes presentes em matrizes de interesse ambiental. É importante ressaltar que quando se estuda o ambiente, os dados analíticos são uma das ferramentas usadas para se avaliar a extensão dos problemas observados que conseqüentemente influenciam as tomadas de decisão. Assim a confiabilidade desses dados é de extrema importância. Neste contexto, este trabalho visa avaliar a confiabilidade analítica das determinações de Carbono Orgânico Total (COT), ferramenta empregada no monitoramento da matéria orgânica em diversos estudos ambientais. Para essa avaliação foram analisados alguns parâmetros de desempenho como limite de detecção e quantificação, repetibilidade e linearidade.

Observing the literature an increasing number of works can be verified that determine potential contaminants that can be present in matrices of environmental interest. It is important to stand out that when studying the environment, the analytical data are one of the tools used to evaluate the extension of the observed problems that consequently influence a decision. Thus the reliability of these data is of extreme importance. In this context, this work aims to evaluate the analytical reliability of the Total organic Carbon (TOC) determination, a tool used in the monitoring of organic substances in diverse ambient studies. For this evaluation some parameters of performance had been analyzed as limit of detection and quantification, repeatability and linearity.

Geomagnetic storms are intervals of time when a sufficiently intense and long-lasting interplanetary convection electric field leads, through a substantial injection of energy into the magnetosphere-ionosphere system, to an intensified ring current, strong enough to exceed some key threshold of the quantifying storm time Dst index. We have studied all the 9 great magnetic storms (peak Dst < -200 nT) observed during the rise and maximum of solar cycle 23 (from 1997 to early 2001), in order to identify their solar and interplanetary causes. Apart of one storm occurred during the period without observations from the Solar and Heliospheric Observatory (SOHO), all of them were related to coronal mass ejections observed by the Large Angle and Spectroscopic Coronagraph (LASCO). The sources of interplanetary southward magnetic field, Bs, responsible for the occurrence of the storms were related to the intensified shock/sheath field, interplanetary magnetic cloud's field, or the combination of sheath-cloud or sheath-ejecta field. It called our attention the fact that one of the events was related to a slow CME, with CME expansion speed not greater than 550 km/s. The purpose of this paper is to address the main sources of large geomagnetic disturbances using the current satellite capability available. As a general conclusion, we found that shock/sheath compressed fields are the most important interplanetary causes of great magnetic storms during this period.