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A rapid (5.5 min) one-step whole blood C–reactive protein (CRP) magnetic permeability immunoassay utilizing monoclonal antibody
conjugated dextran iron oxide nanoparticles (70 nm) as superparamagnetic labels and mixed fractions (1:1 ratio of 15–40 and
60 μm) of polyclonal anti-CRP conjugated silica microparticles for enhanced sedimentation is described. In this one-step assay
procedure, a whole blood sample (4 μl) is applied to an assay glass vial, containing both antibody conjugates, and mixed for
30 s. The target analyte, CRP, forms a sandwich complex between the conjugated nanoparticles and microparticles, and, subsequently,
the complex sediments under normal gravitation within 5 min to the bottom of the vial. The magnetic permeability increase
of the sediment due to the presence of the complexed superparamagnetic nanoparticles is determined using an inductance-based
transducer. Assayed patient whole blood samples were compared with the Abbott Diagnostics Architect reference method. A strong
linear correlation was observed for the CRP concentration range 0–260 mg/l in whole blood (y=1.001x+0.42, R
2=0.982, n=50). The CRP assay presented showed a limit of detection of 3 mg/l and a total imprecision (coefficient of variation) of
10.5%. On the basis of our observations, we propose a rapid, one-step, CRP assay for near-patient testing. 相似文献
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Determination of primary amino acids in wines by high performance liquid magneto-chromatography 总被引:1,自引:0,他引:1
Eight amino acids (ethanolamine, glycine, alanine, β-aminobutyric acid, leucine, methionine, histidine and asparagine) were identified and quantified in Spanish wines by high performance liquid magneto-chromatography (HPLMC) with UV-V spectrophotometry. For this method, the amino acids are first complexed with mono(1,10-phenanthroline)-Cu(II) to confer them paramagnetic properties, and then separated by application of a low magnetic field intensity (5.5 mT) to the stationary phase contained in the chromatographic column. Principal components analysis of the results obtained grouped together the wine samples according to their denomination of origin: “Ribera del Duero”, “Rueda” or “Rioja” (Spain). Through cluster analysis, a series of correlations was also observed among certain amino acids, and between these groupings and the type of wine. These clusters were found to reflect the role played by the amino acids as primary or secondary nutrients for the bacteria involved in alcoholic and malolactic fermentation. 相似文献
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Susana Liébana Delfina Brandão Pilar Cortés Susana Campoy Salvador Alegret María Isabel Pividori 《Analytica chimica acta》2016
A magneto-genosensing approach for the detection of the three most common pathogenic bacteria in food safety, such as Salmonella, Listeria and Escherichia coli is presented. The methodology is based on the detection of the tagged amplified DNA obtained by single-tagging PCR with a set of specific primers for each pathogen, followed by electrochemical magneto-genosensing on silica magnetic particles. A set of primers were selected for the amplification of the invA (278 bp), prfA (217 bp) and eaeA (151 bp) being one of the primers for each set tagged with fluorescein, biotin and digoxigenin coding for Salmonella enterica, Listeria monocytogenes and E. coli, respectively. The single-tagged amplicons were then immobilized on silica MPs based on the nucleic acid-binding properties of silica particles in the presence of the chaotropic agent as guanidinium thiocyanate. The assessment of the silica MPs as a platform for electrochemical magneto-genosensing is described, including the main parameters to selectively attach longer dsDNA fragments instead of shorter ssDNA primers based on their negative charge density of the sugar-phosphate backbone. This approach resulted to be a promising detection tool with sensing features of rapidity and sensitivity very suitable to be implemented on DNA biosensors and microfluidic platforms. 相似文献
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Simulation of forced convection of FMWNT-water (functionalized multi-walled carbon nano-tubes) nano-fluid in a micro-channel under a magnetic field in slip flow regime is performed. The micro-channel wall is divided into two portions. The micro-channel entrance is insulated while the rest of length of the micro-channel has constant temperature (TC). Moreover, the micro-channel domain is exposed to a magnetic field with constant strength of B0. High temperature nano-fluid (TH) enters the micro-channel and exposed to its cold walls. Slip velocity boundary condition along the walls of the micro-channel is considered. Governing equations are numerically solved using FORTRAN computer code based on the SIMPLE algorithm. Results are presented as the velocity, temperature, and Nusselt number profiles. Greater Reynolds number, Hartmann number, and volume fraction related to more heat transfer rate; however, the effects of Ha and ϕ are more noteworthy at higher Re. 相似文献
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The forced convection of nanofluid flow in a long microchannel is studied numerically according to the finite volume approach and by using a developed computer code. Microchannel domain is under the influence of a magnetic field with uniform strength. The hot inlet nanofluid is cooled by the heat exchange with the cold microchannel walls. Different types of nanoparticles such as Al2O3 and Ag are examined while the base fluid is considered as water. Reynolds number are chosen as Re=10 and Re=100. Slip velocity and temperature jump boundary conditions are simulated along the microchannel walls at different values of slip coefficient for different amounts of Hartmann number. The investigation of magnetic field effect on slip velocity and temperature jump of nanofluid is presented for the first time. The results are shown as streamlines and isotherms; moreover the profiles of slip velocity and temperature jump are drawn. It is observed that more slip coefficient corresponds to less Nusselt number and more slip velocity especially at larger Hartmann number. It is recommended to use Al2O3-water nanofluid instead of Ag-water to increase the heat transfer rate from the microchannel walls at low values of Re. However at larger amounts of Re, the nanofluid composed of nanoparticles with higher thermal conductivity works better. 相似文献
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