RESUMO
This work presents the effect of the silicocarnotite (SC) and nagelschmidtite (Nagel) phases on in vitro osteogenesis. The known hydroxyapatite of biological origin (BHAp) was used as a standard of osteoconductive characteristics. The evaluation was carried out in conventional and osteogenic media for comparative purposes to assess the osteogenic ability of the bioceramics. First, the effect of the material on cell viability at 24 h, 7 and 14 days of incubation was evaluated. In addition, cell morphology and attachment on dense bioceramic surfaces were observed by fluorescence microscopy. Specifically, alkaline phosphatase (ALP) activity was evaluated as an osteogenic marker of the early stages of bone cell differentiation. Mineralized extracellular matrix was observed by calcium phosphate deposits and extracellular vesicle formation. Furthermore, cell phenotype determination was confirmed by scanning electron microscope. The results provided relevant information on the cell attachment, proliferation, and osteogenic differentiation processes after 7 and 14 days of incubation. Finally, it was demonstrated that SC and Nagel phases promote cell proliferation and differentiation, while the Nagel phase exhibited a superior osteoconductive behavior and could promote MC3T3-E1 cell differentiation to a higher extent than SC and BHAp, which was reflected in a higher number of deposits in a shorter period for both conventional and osteogenic media.
Assuntos
Diferenciação Celular , Cerâmica , Durapatita , Osteoblastos , Osteogênese , Silicatos , Animais , Camundongos , Durapatita/química , Durapatita/farmacologia , Cerâmica/química , Cerâmica/farmacologia , Osteoblastos/citologia , Osteoblastos/metabolismo , Osteoblastos/efeitos dos fármacos , Silicatos/química , Silicatos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Materiais Biocompatíveis/química , Fosfatase Alcalina/metabolismo , Compostos de Cálcio/farmacologia , Compostos de Cálcio/química , Sobrevivência Celular/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Células 3T3 , Linhagem CelularRESUMO
Multi-walled carbon nanotubes (MWCNTs) are of multidisciplinary scientific interest due to their exceptional physicochemical properties and a broad range of applications. However, they are considered potentially toxic nanoparticles when they accumulate in the environment. Given their ability to oxidize resistant polymers, mycorremediation with lignocellulolytic fungi are suggested as biological alternatives to the mineralization of MWCNTs. Hence, this study involves the ability of two fungi specie to MWCNTs biotransformation by laccase and peroxidases induction and evaluation in vivo of its toxicity using Caenorhabditis elegans worms as a model. Results showed that the fungi Penicillium chrysogenum and Pleurotus ostreatus were capable to grow on media with MWCNTs supplemented with glucose or lignin. Activities of lignin-peroxidase, manganese-peroxidase, and laccase in cultures of both fungi were induced by MWCNTs. Raman, FTIR spectroscopy, HR-TEM, and TGA analyses of the residue from the cultures of both fungi revealed structural modifications on the surface of MWCNTs and its amount diminished, correlating the MWCNTs structural modifications with the laccase-peroxidase activities in the fungal cultures. Results indicate that the degree of toxicity of MWCNTs on the C. elegans model was enhanced by the structure modification associated with the fungal ligninolytic activity. The toxic effect of MWCNTs on the in vivo model of worms reveals the increment of reactive oxygen species as a mechanism of toxicity. Findings indicate that the MWCNTs can be subject in nature to biotransformation processes such as the fungal metabolism, which contribute to modify their toxicity properties on susceptible organisms and contributing to environmental elimination.
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The Raman spectra of copper tellurides are nearly unknown. This is due not only to the difficulty in obtaining single-phase specimens, but also to the low inelastic light scattering efficiency of Cu2-xTe. To date, only the Raman spectrum of the vulcanite phase, CuTe, has been both measured and calculated by density functional theory. The authors of the commented work reported the Raman spectra of Cu2Te, Cu1.6Te and Cu1.25Te samples. However, the assignment of the measured modes has been defective and their Raman spectra lack some of the features usually found for copper tellurides.
RESUMO
The effects of the simultaneous incorporation of Cu and O in CdSe films grown by sputtering are presented. The Cu and O contents varied between 1 and 5 at.% in films deposited at 150, 200, 250 and 300 °C. Concentrations of 2, 3, 4 and 5 at.% of CuO in the target promoted the formation of copper selenide clusters immersed within the CdSe:Cu:O host. Energy considerations (enthalpy of formation and bond dissociation energy) were used to discuss the absence of copper oxide and the formation of copper selenide aggregates, as well as the film thickness dependence on the concentration of CuO in the target. The band gap of the films ranged from 1.21 to 2.07 eV, depending upon growth conditions. Significant below-band-gap absorption was observed which was ascribed to the copper selenide micro and nano clusters. Good crystalline quality of the films, for high substrate temperatures, was evidenced through the appearance of overtones of the vibrational longitudinal optic modes detected by Raman micro spectroscopy. It was determined that the electronic properties, optical transmission and electrical conductivity depended on the chemical composition and crystalline structure. This characteristic is relevant because through copper and oxygen co-doping is possible to control these technologically important physical properties of CdSe in a simple and reliable manner.
RESUMO
Mexican migrant farm workers are one of the poorest and most marginalized social groups within the country. They face the double burden of malnutrition, food insecurity, as well as harsh living and labor conditions. Objective: To examine the relationship between household food insecurity (HFI) and obesity in a population of migrant farm workers in highly modernized agribusiness areas of Northwest Mexico. Methods: This was a cross-sectional study with a concentric (site) (n = 146 households) and systematic selection of participants (adult men and women). Methods included questionnaires regarding socio-demographic characteristics, food security, diet (two non-consecutive 24-h recalls), and physical activity (PA). Anthropometric data included height, weight, and waist circumference. Data analysis covered descriptive statistics, multivariate linear and logistic regression. Results: Sample showed 75% prevalence of overweight and obesity, while 87% of households reported some level of HFI. Mild HFI resulted in five times more probability of farm workers' obesity (OR = 5.18, 95% CI: 1.37-19.58). However, there was a protective effect of HFI for obesity among men (OR 0.089, 95% CI: 0.01-0.58) in a context of intense labor-related PA. Conclusion: There is a difference by gender in the relationship of HFI with obesity prevalence related perhaps to the energy expenditure of male agricultural migrant workers.
Assuntos
Doenças dos Trabalhadores Agrícolas/etiologia , Fazendeiros/estatística & dados numéricos , Abastecimento de Alimentos/estatística & dados numéricos , Obesidade/etiologia , Migrantes/estatística & dados numéricos , Adulto , Doenças dos Trabalhadores Agrícolas/epidemiologia , Estudos Transversais , Feminino , Humanos , Modelos Lineares , Modelos Logísticos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Sobrepeso/etiologia , Prevalência , Fatores de Risco , Fatores Socioeconômicos , Adulto JovemRESUMO
Layered-structure materials are currently relevant given their quasi-2D nature. Knowledge of their physical properties is currently of major interest. Niobium ditelluride possesses a monoclinic layered-structure with a distortion in the tellurium planes. This structural complexity has hindered the determination of its fundamental physical properties. In this work, NbTe2 crystals were used to elucidate its structural, compositional, electronic and vibrational properties. These findings have been compared with calculations based on density functional theory. The chemical composition and elemental distribution at the nanoscale were obtained through atom probe tomography. Ultraviolet photoelectron spectroscopy allowed the first determination of the work function of NbTe2. Its high value, 5.32 eV, and chemical stability allow foreseeing applications such as contact in optoelectronics. Raman spectra were obtained using different excitation laser lines: 488, 633, and 785 nm. The vibrational frequencies were in agreement with those determined through density functional theory. It was possible to detect a theoretically-predicted, low-frequency, low-intensity Raman active mode not previously observed. The dispersion curves and electronic band structure were calculated, along with their corresponding density of states. The electrical properties, as well as a pseudo-gap in the density of states around the Fermi energy are characteristics proper of a semi metal.
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We sequenced the mitochondrial cytochrome b gene of 141 lowland tapirs (Tapirus terrestris) - representing the largest geographical distribution sample of this species studied across of South America to date. We compare our new data regard to two previous works on population structure and molecular systematics of T. terrestris. Our data agree with the Thoisy et al.'s work in (1) the Northern Western Amazon basin was the area with the highest gene diversity levels in T. terrestris, being probably the area of initial diversification; (2) there was no clear association between haplogroups and specific geographical areas; (3) there were clear population decreases during the last glacial maximum for the different haplogroups detected, followed by population expansions during the Holocene; and (4) our temporal splits among different T. terrestris haplogroups coincided with the first molecular clock approach carried out by these authors (fossil calibration). Nevertheless, our study disagreed regard to other aspects of the Thoisy et al.'s claims: (1) meanwhile, they detected four relevant clades in their data, we put forward six different relevant clades; (2) the Amazon River was not a strong barrier for haplotype dispersion in T. terrestris; and (3) we found reciprocal monophyly between T. terrestris and T. pinchaque. Additionally, we sequenced 42 individuals (T. terrestris, T. pinchaque, T. bairdii, and the alleged "new species", T. kabomani) for three concatenated mitochondrial genes (Cyt-b, COI, and COII) agreeing quite well with the view of Voss et al., and against of the claims of Cozzuol et al. Tapirus kabomani should be not considered as a full species with the results obtained throughout the mitochondrial sequences.
Assuntos
Variação Genética , Perissodáctilos/classificação , Perissodáctilos/genética , Filogenia , Filogeografia , Animais , Evolução Molecular , Genes Mitocondriais , Heterogeneidade Genética , Genética Populacional , Geografia , América do SulRESUMO
El pan elaborado a base de trigo, es uno de los productos de mayor consumo en la dieta de la población mexicana siendo un importante aportador de energía y proteína. En este estudio se determinó la composición proximal y contenido de minerales de pan preparado en forma artesanal e industrial. Asimismo se hizo la comparación sobre el costo por gramo de proteína y de energía en cada uno de los tratamientos. Se analizaron siete tipos de panes (pan blanco: bolillo (T), virginia y de caja; pan dulce: cochita, cuernos, bollos y donas). En la determinación de la composición proximal (humedad, proteína, grasa, ceniza y carbohidratos por diferencia) se utilizó la metodología analítica oficial (AOAC, 1984) y el contenido de minerales (Na, K, Ca, Mg, Fe y Zn) por espectrofotometría de absorción atómica. Basado en encuestas de recordatorio de 24 hrs se calculó el consumo diario de cada tipo de pan y se determinó el porcentaje de la recomendación calórica y proteica cubierta por consumo de pan. Se encontró que existen diferencias significativas (p<0.05) con respecto al contenido de macro y micronutrimentos, entre los panes elaborados por los dos tipos de industria panificadora. También se encontró, en la mayoría de los casos, que el pan blanco y pan dulce de la panadería industrial tienen mayor costo por gramo de proteína y energía que el pan tradicional (p<0.05). El contenido de grasa de algunos panes en ambas panaderías fue superior al establecido en la norma oficial Mexicana. El contenido de Ca y Na fue mayor en el pan industrial mientras que el resto de los minerales (K,Mg, Fe, Zn) fueron mas elevados en el pan tradicional
Assuntos
Pão , Química , Tabela de Composição de Alimentos , México , Ciências da NutriçãoRESUMO
El mivacurio es un relajante muscular no despolarizante de corta acción sintetizado recientemente. Decidimos evaluar sus efectos neuromusculares y cardiovasculares por dosis respuesta en pacientes pediátricos. Método: Se estudiaron 60 pacientes entre 2 a 10 años de edad con estado físico I-II según ASA para cirugía electiva ambulatoria en procedimientos cortos (1 hora de duración) que requerían intubación endotraqueal: La anestesia fue bajo halothano-óxido nitroso y oxígeno. A treinta niños se le administró mivacurio a dosis de 150 µg/kg y treinta pacientes recibieron una dosis de 250 µg/kg ambos en bolo por vía endovenosa. La dosis se estimo a 2 x DE95. La respuesta neuromuscular se midió a través de la fuerza de contracción en forma indirecta del nervio cubital por estimulo de tren de cuatro a 2 HZ. La frecuencia cardiaca, presión arterial se evalúo cada minuto durante la inducción. Resultados: A dosis de 150 mg/kg de mivacurio el tiempo de latencia fue de 3.50 ñ 0.65 min; el tiempo de acción de 13.00 ñ 2.87 min y el tiempo de recuperación al 25 por ciento (T1) fue de 12.03 ñ 2.13 min. A la dosis de 250 µg/kg el periodo de latencia fue de 3.24 ñ 0.66 min, el periodo de acción de 14.08 ñ 2.76 min, y el tiempo de recuperación (T1) de 16.01 ñ 3.22 min. No hubo diferencias significativas en ambos grupos. Por otra parte, las variaciones cardiovasculares no fueron significativas, a pesar de que hubo discreta disminución en la presión arterial con elevación mínima en la frecuencia cardiaca a dosis de 250 µg/kg. en un niño se observo rash pasajero. NO se observaron diferencias significativas al comparar los efectos neuromusculares y cardiovasculares con dosis de mivacurio de 150-250 µg/kg en pacientes pediátricos en edades comprendidas de 2 a 10 años en anestesia general con halotano-oxígeno-óxido nitroso para cirugía ambulatoria
Assuntos
Lactente , Pré-Escolar , Criança , Humanos , Masculino , Feminino , Prega Vocal/efeitos dos fármacos , Fármacos Neuromusculares não Despolarizantes/administração & dosagem , Fármacos Neuromusculares não Despolarizantes/farmacocinética , Halotano/administração & dosagem , Isoquinolinas/administração & dosagem , Isoquinolinas/farmacocinética , Óxido Nitroso/administração & dosagem , Oxigênio/administração & dosagem , Período de Recuperação da Anestesia , Relaxamento Muscular , Tempo de ReaçãoRESUMO
Se evalúan los efectos de dos analgésicos morfinicos a dosis equipotentes, alfentanil fentanyl en anestesia general endovenosa (propofol-vecuronio) y como testigo una anestesia general inhalatoria (halotano-vecuronio). Ciento ochenta pacientes pediátricos divididos en tres grupos. La indución I: 60 Alfentanil 50 µg/kg, propofol 2.5 mg/kg, vecuronio 100 µg/kg. 60 fentanyl 5 µg/kg propofol 2.5 mg/kg, vecuronio 100 µg/kg III:60 lidocaína 1 mg/kg, propofol 2.5 mg/kg vecuronio 100 µg/kg. Previa atropina 0.01 mg/kg todas I.V. El mantenimiento alfentanil, fentanyl, vecuronio, propofol (infusión), Halotano (inhalación), a dosis respuesta. Variables de estudio: dosis, tiempos de drogas evolución cardiovascular, recuperación de la conciencia, analgesia residual, efectos secundarios. Consumo de alfentanil 32 µg/kg cada 9.45 min. fentanyl 2.2 µg/kg cada 33.09 min; propofol-alfentanil 7.26 mg/kg/h, propofol fentanyl 6.92 mg/kg/h. Halotano 1.4 por ciento; vecuronio-propofol 40.3 µg/kg cada 23.14 min. y vecuronio-halotano 29.5 µg/kg cada 30.24 minutos (significativo). La calidad de relajación de cuerdas vocales fue exelente en los 3 grupos (NS). Excelente protección cardiovascular durante la intubación (respuesta presora) y mantenimiento con alfentanil y fentanyl, no así en el grupo testigo (halotano). La duración de analgesia residual promedio con algentanil fue de 20.34 min. con fentanyl de 35.12 min. y de Halotano de 7.05 minutos, significativo para los morfinicos. La incidencia de náusea y vómito fue semejante en los tres grupos (NS). Se concluye de los resultados, que las ventajas descritas por alfentanil representa una verdadera alternativa para la anestesia inhalatoria tradicional en pediatría para cirugía ambulatoria