RESUMO
Functional connectivity in resting-state functional magnetic resonance imaging (rs-fMRI) has received substantial attention since the initial findings of Biswal et al. Traditional network correlation metrics assume that the functional connectivity in the brain remains stationary over time. However, recent studies have shown that robust temporal fluctuations of functional connectivity among as well as within functional networks exist, challenging this assumption. In this study, these dynamic correlation differences were investigated between the dorsal and ventral sensorimotor networks by applying the dynamic conditional correlation model to rs-fMRI data of 20 healthy subjects. k-Means clustering was used to determine an optimal number of discrete connectivity states (k = 10) of the sensorimotor system across all subjects. Our analysis confirms the existence of differences in dynamic correlation between the dorsal and ventral networks, with highest connectivity found within the ventral motor network.
Assuntos
Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética , Modelos Neurológicos , Vias Neurais/diagnóstico por imagem , Dinâmica não Linear , Descanso/fisiologia , Adulto , Encéfalo/fisiologia , Mapeamento Encefálico , Análise por Conglomerados , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiologia , Oxigênio/sangue , Adulto JovemRESUMO
Quantitative detection of molecules of interest from biological and environmental samples in a rapid manner, particularly with a relevant concentration range, is imperative to the timely assessment of human diseases and environmental issues. In this work, we employed the microwave-accelerated bioassay (MAB) technique, which is based on the combined use of circular bioassay platforms and microwave heating, for rapid and quantitative detection of Glial Fibrillary Acidic Protein (GFAP) and Shiga like toxin (STX 1). The proof-of-principle use of the MAB technique with the circular bioassay platforms for the rapid detection of GFAP in buffer based on colorimetric and fluorescence readouts was demonstrated with a 900W kitchen microwave. We also employed the MAB technique with a new microwave system (called the iCrystal system) for the detection of GFAP from mice with brain injuries and STX 1 from a city water stream. Control bioassays included the commercially available gold standard bioassay kits run at room temperature. Our results show that the lower limit of detection (LLOD) of the colorimetric and fluorescence based bioassays for GFAP was decreased by ~1000 times using the MAB technique and our circular bioassay platforms as compared to the commercially available bioassay kits. The overall bioassay time for GFAP and STX 1 was reduced from 4h using commercially available bioassay kits to 10min using the MAB technique.
Assuntos
Técnicas Biossensoriais , Proteína Glial Fibrilar Ácida/isolamento & purificação , Micro-Ondas , Toxina Shiga I/isolamento & purificação , Animais , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Fluorescência , Proteína Glial Fibrilar Ácida/química , Humanos , Camundongos , Toxina Shiga I/química , Microbiologia da ÁguaRESUMO
In this paper, we demonstrate the application of Metal-Assisted and Microwave-Accelerated Evaporative Crystallization (MA-MAEC) technique to rapid and selective crystallization of a small drug compound. i.e. acetaminophen. Subsequent characterization of the crystals by optical microscopy, powder X-ray diffraction (PXRD) and Raman spectroscopy showed quantitatively selective growth of different crystal forms at various experimental conditions. Acetaminophen crystals were grown predominantly as Form I (99%) on blank glass slides at room temperature. Form II crystals with 39% purity grown on SIFs using microwave energy.