RESUMO
Leishmaniasis is a neglected disease that affects 12 million people living mainly in developing countries. Herein, 24 new N-oxide-containing compounds were synthesized followed by in vitro and in vivo evaluation of their antileishmanial activity. Compound 4f, a furoxan derivative, was particularly remarkable in this regard, with EC50 value of 3.6 µM against L. infantum amastigote forms and CC50 value superior to 500 µM against murine peritoneal macrophages. In vitro studies suggested that 4f may act by a dual effect, by releasing nitric oxide after biotransformation and by inhibiting cysteine protease CPB (IC50: 4.5 µM). In vivo studies using an acute model of infection showed that compound 4f at 7.7 mg/Kg reduced ~90% of parasite burden in the liver and spleen of L. infantum-infected BALB/c mice. Altogether, these outcomes highlight furoxan 4f as a promising compound for further evaluation as an antileishmanial agent.
Assuntos
Antiprotozoários/farmacologia , Desenho de Fármacos , Leishmania infantum/efeitos dos fármacos , Óxidos/farmacologia , Animais , Antiprotozoários/síntese química , Antiprotozoários/química , Biomarcadores/metabolismo , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Ligantes , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Masculino , Camundongos , Simulação de Acoplamento Molecular , Óxido Nítrico/análise , Nitritos/análise , Oxidiazóis/síntese química , Oxidiazóis/química , Óxidos/síntese química , Óxidos/química , Carga Parasitária , Pichia/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Proteínas de Protozoários/metabolismoRESUMO
Natural or synthetic biomaterials are increasingly being used to support bone tissue repair or substitution. The combination of natural calcium phosphates with biocompatible alloys is an important route towards the development of new biomaterials with bioperformance and mechanical responses to mimic those of human bones. This article evaluated the structural, physical, mechanical and biological properties of a new mechanical improved nanocomposite elaborated by association of fish biphasic calcium phosphate (BCP) and niobium pentoxide (Nb2O5). The nanocomposite (Nb-BCP) and the pure BCP, used as a positive control, were obtained by powder metallurgy. The density, porosity and microhardness were measured. The structural analysis was determined by X-ray diffraction (XRD) and the biological properties were studied in histological sections of critical size calvaria defects in rats, 7, 15, 30, 45 and 60 days after implantation of disks of both materials. Morphological description was made after scanning electron microscopy (SEM) and optical microscopy analysis. After sintering, the Nb-BCP nanocomposite presented four crystalline phases: 34.36% calcium niobate (CaNb2O6), 21.68% phosphorus niobium oxide (PNb9O25), 42.55% ß-tricalcium phosphate (Ca3(PO4)2) and 1.31% of niobium pentoxide (Nb2O5) and exhibited increases of 17% in density, 66% in Vickers microhardness and 180% in compressive strength compared to pure BCP. In vivo study, showed biocompatibility, bioactivity and osteoconductivity similar to pure BCP. SEM showed the formation of globular accretions over the implanted nanocomposites, representing one of the stages of bone mineralization. In conclusion, the BCP and Nb2O5 formed a nanocomposite exhibiting characteristics that are desirable for a biomaterial, such as bioperformance, higher ß-TCP percentage and improved physical and mechanical properties compared to pure BCP. These characteristics demonstrate the promise of this material for supporting bone regeneration.
Assuntos
Substitutos Ósseos/química , Fosfatos de Cálcio/química , Nióbio/química , Osseointegração , Óxidos/química , Fraturas Cranianas/terapia , Animais , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/farmacologia , Substitutos Ósseos/uso terapêutico , Prótese Ancorada no Osso , Interface Osso-Implante/patologia , Fosfatos de Cálcio/síntese química , Fosfatos de Cálcio/uso terapêutico , Modelos Animais de Doenças , Hidroxiapatitas/síntese química , Hidroxiapatitas/química , Hidroxiapatitas/uso terapêutico , Masculino , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos/química , Nanocompostos/uso terapêutico , Nióbio/uso terapêutico , Osseointegração/efeitos dos fármacos , Óxidos/síntese química , Óxidos/uso terapêutico , Ratos , Ratos Wistar , Fraturas Cranianas/patologia , Difração de Raios XRESUMO
Semiconductors based on Fe/Nb oxides can present both solar sensitivity and high catalytic activity. However, there is still a lack regarding the comparison between different routes to produce Fe/Nb-based solar photocatalysts and the evaluation of the impact of the synthesis operating conditions on the material properties. In this work, Fe/Nb2O5 ratio, type of precipitating agent, presence/absence of washing stage, and temperature of calcination were verified to be the most relevant parameters in the synthesis by the co-precipitation method. These factors led to remarkable differences in the properties and performance of the photocatalysts produced by each distinct synthesis route. Composition, iron species present in the materials, crystallinity characteristics, and pH of the catalysts were affected, leading to different photocatalytic activities under UV-Vis light. Due to their characteristics, the synthesized materials are potential photocatalysts for application in solar processes. Graphical abstract á .
Assuntos
Ferro/química , Nióbio/química , Óxidos/química , Óxidos/síntese química , Semicondutores , Raios Ultravioleta , Purificação da Água/métodos , Catálise , Precipitação Química , Processos FotoquímicosRESUMO
INTRODUCTION: The main purpose of this study was to evaluate the biocompatibility and bioactivity of a new mineral trioxide aggregate (MTA)-based endodontic sealer, MTA Fillapex (MTA-F; Angelus, Londrina, Brazil), in human cell culture. METHODS: Human osteoblast-like cells (Saos-2) were exposed for 1, 2, 3, and 7 days to MTA-F, Epiphany SE (EP-SE; SybronEndo, Orange, CA), and zinc oxide-eugenol sealer (ZOE). Unexposed cultures were the control group (CT). The viability of the cells was assessed by MTT assay and the morphology by scanning electron microscopy (SEM). The bioactivity of MTA-F was evaluated by alkaline phosphatase activity (ALP) and the detection of calcium deposits in the culture with alizarin red stain (ARS). Energy-dispersive X-ray spectroscopy (EDS) was used to chemically characterize the hydroxyapatite crystallites (HAP). Saos-2 cells were cultured for 21 days for ARS and SEM/EDS. ARS results were expressed as the number of stained nodules per area. Statistical analysis was performed with analysis of variance and Bonferroni tests (P < .01). RESULTS: MTA-F exposure for 1, 2, and 3 days resulted in increased cytotoxicity. In contrast, viability increased after 7 days of exposure to MTA-F. Exposure to EP-SE and ZOE was cytotoxic at all time points. At day 7, ALP activity increase was significant in the MTA-F group. MTA-F presented the highest percentage of ARS-stained nodules (MTA-F > CT > EP-SE > ZOE). SEM/EDS analysis showed hydroxyapatite crystals only in the MTA-F and CT groups. In the MTA-F group, crystallite morphology and chemical composition were different from CT. CONCLUSIONS: After setting, the cytotoxicity of MTA-F decreases and the sealer presents suitable bioactivity to stimulate HAP crystal nucleation.
Assuntos
Compostos de Alumínio/farmacologia , Compostos de Cálcio/farmacologia , Durapatita/química , Osteoblastos/efeitos dos fármacos , Óxidos/farmacologia , Materiais Restauradores do Canal Radicular/farmacologia , Silicatos/farmacologia , Calcificação de Dente/efeitos dos fármacos , Compostos de Alumínio/síntese química , Compostos de Alumínio/química , Compostos de Alumínio/toxicidade , Análise de Variância , Compostos de Cálcio/síntese química , Compostos de Cálcio/química , Compostos de Cálcio/toxicidade , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cristalização , Combinação de Medicamentos , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Óxidos/síntese química , Óxidos/química , Óxidos/toxicidade , Materiais Restauradores do Canal Radicular/síntese química , Materiais Restauradores do Canal Radicular/química , Materiais Restauradores do Canal Radicular/toxicidade , Silicatos/síntese química , Silicatos/química , Silicatos/toxicidade , Espectrometria por Raios X , Estatísticas não ParamétricasRESUMO
Agave bagasse is a byproduct generated in the mezcal industry. Normally it is burned to reduce its volume, then a byproduct is generated in the form of residual ash, which can contaminate the water in rivers and lakes near the production places called "mezcaleras". This report details measurements of the Agave Salmiana fiber transformation after the burning process. The wasted ash was heated at 950°C, and then hydrolyzed. The compounds were indentified using the X-ray diffraction. The images obtained by scanning electron microscope showed all the morphological transformations of the lime through the whole process. Thermal, elemental and morphological characterization of the agave bagasse were done. Experiments showed that 16% of ash was produced in the burning process of agave bagasse (450°C), and 66% of the ash remains after heating (950°C) in the form of calcium oxide. The results show an important renewable source of calcium compounds, due to the high production of agave based beverages in México.
Assuntos
Compostos de Cálcio/síntese química , Celulose/química , Poluentes Ambientais/química , Óxidos/síntese química , Gerenciamento de Resíduos/métodos , Agave , Celulose/análise , Celulose/ultraestrutura , Conservação dos Recursos Naturais , Poluentes Ambientais/análise , Incineração , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Termogravimetria , Difração de Raios XRESUMO
This paper reports for the first time the synthesis and characterization of trifluoromethyl fluoroformyl trioxicarbonate, CF(3)OC(O)OOOC(O)F. The new trioxide is obtained from the gas-phase photolytic reaction of CF(3)C(O)OC(O)CF(3) and FC(O)C(O)F at 223-228 K. It is a very thermally labile molecule that decomposes at room temperature by rupture of either of the CF(3)OC(O)O-O-OC(O)F bonds. These bonds are nonequivalent, and a branching ratio of 0.8 for fragmentation through the CF(3)OC(O)OO-OC(O)F bond was obtained. Unambiguous identification was possible through reaction of the trioxide with an excess of NO(2). Potential-energy surfaces (PES) of the different rotamers were studied by the B3LYP/6-311+G* method, and analysis of the IR frequency of the possible mixture of rotamers agrees excellently with the experimental IR spectrum. This molecule is the first nonsymmetric acyl trioxide reported in the literature.
Assuntos
Carbonatos/química , Hidrocarbonetos Fluorados/química , Óxidos/química , Carbonatos/síntese química , Simulação por Computador , Hidrocarbonetos Fluorados/síntese química , Modelos Químicos , Óxidos/síntese química , Espectrofotometria Infravermelho , TemperaturaRESUMO
Ba(Mn1/3Nb2/3)O3 ceramics were synthesized by the microwave-hydrothermal process. Crystalline, single-phase, needle-like materials were obtained with high anisotropy and aspect ratio. Large crystals could be prepared from a direct combination of nanosized crystals under microwaves through an oriented attachment mechanism. Infrared and Raman spectroscopies showed perfect agreement with group-theoretical approaches for a trigonal, P3m1 structure. Franck-Condon modes were identified in Raman scattering experiments conducted in different wavelengths, laser powers, and temperatures. The results showed that the Mn ions exhibit a particular role in the lattice dynamics in complex perovskites.
Assuntos
Bário/química , Elétrons , Manganês/química , Nióbio/química , Óxidos/síntese química , Temperatura , Micro-Ondas , Óxidos/química , Análise Espectral Raman/métodos , VibraçãoRESUMO
This study evaluated the influence of addition of 10% calcium chloride (CaCl(2)) on the setting time, solubility, disintegration, and pH of white MTA (WMTA) and white Portland cement (WPC). A test of the setting time was performed following the #57 ADA specifications and a test of the final setting time according to the ASTM. For the solubility tests disintegration and pH, Teflon rings were filled with the cements and weighed after setting. After 24 h in a desiccator, they were once again weighed. Thereafter, they were immersed in MiliQ water for 24 and 72 h and 7, 14, and 28 days, with maintenance in the desiccator and weighing between periods. The pH of water in which the rings were immersed was measured immediately after contact with them and in the other periods. The addition of CaCl(2) provided a significant reduction (50%) in the initial setting time of cements. The final setting time of WMTA was reduced in 35.5% and the final setting time of WPC in 68.5%. The WMTA with CaCl(2) absorbed water and gained weight with time, except for in the 24-h period. The addition of CaCl(2) to the WPC reduced its solubility. The addition of CaCl(2) increased the pH of WMTA in the immediate period and at 24 and 72 h and for WPC in the immediate period and at 24 h. The addition of CaCl(2) to WMTA and WPC reduced the setting times and solubility of both and increased the pH of cements in the initial periods.
Assuntos
Compostos de Alumínio/química , Cloreto de Cálcio/química , Compostos de Cálcio/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Compostos de Alumínio/síntese química , Compostos de Cálcio/síntese química , Meios de Contraste , Cimentos Dentários/síntese química , Cimentos Dentários/química , Combinação de Medicamentos , Concentração de Íons de Hidrogênio , Teste de Materiais , Óxidos/síntese química , Materiais Restauradores do Canal Radicular/síntese química , Silicatos/síntese química , Solubilidade , Fatores de TempoRESUMO
Two new germanates, Ge7O12(OH)4 (C4N3H13)(0.5)(H2O)5 (1) and Ge7O12(OH)4(H2O)6 (2) have been synthesized under hydrothermal conditions and characterized by IR spectroscopy, powder XRD, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in cubic space group P3m (No. 215) with a = b = c = 7.7119(5) A, v = 458.65(5) A(3), z = 1. Compound 2: cubic, P3m, a = b = c = 7.7653(17) A, v = 457.48(17) A(3), z = 1. Both germanates keep the same topological novel inorganic framework, which is assembled from Ge4(OH)4 cubane and chiral intertwined Ge-O double helices.
Assuntos
Hidrocarbonetos Aromáticos com Pontes/síntese química , Germânio/química , Óxidos/síntese química , Hidrocarbonetos Aromáticos com Pontes/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Molecular , Óxidos/química , Estereoisomerismo , TemperaturaRESUMO
The results of a study on the use of Hansch's series design, cluster methodology, for the generation of new benzo[1,2-c]1,2,5-oxadiazole N-oxide derivatives as antitrypanosomal compounds are described. In vitro activity of these compounds was tested against Tulahuen 2 strain of Trypanosoma cruzi. Clearly, the Hansch methodology allowed identifying two cluster-substituents suitable for further structural modifications. The most effective drugs, derivatives 11, 18, and 21, with 50% inhibitory concentration (IC(50)) of the same order as that of the reference drug, represent an excellent structural point of chemical modifications for the design of future drugs. Preliminary results from the study of the mechanism of action of these benzofuroxans point to perturbation of the mitochondrial electron chain, inhibiting parasite respiration.