Carbon nanotube wiring for signal amplification of electrochemical magneto immunosensors: application to myeloperoxidase detection

In this work, chronoamperometric myelo-peroxidase (MPO) detection was accomplished using immunofunctionalized magnetic microparticles (MPs), disposable carbon screen-printed electrodes (C-SPEs), and a ready-to-use commercially available tetramethylbenzidine (TMB)-based enzymatic substrate. In order to reach the limit of detection (LOD) needed to study real blood serum samples, assay performance was additionally improved by exploiting CNT wiring, which amplified the signal and decreased the LOD. The optimized assay can be performed in 30 min and yields LODs of 6 and 55 ng mL^?1 in PBS and undiluted human serum, respectively, making it useful for the identification of patients at risk of cardiovascular disease. These results demonstrate that electrode nanostructuring can be accomplished “post-assay,” which favors the development of enhanced magneto immunosensors based on the exploitation of cheap and simple SPE devices.     

Algebras of Cauchy continuous maps

A condition of vibrational stabilizability for a class of linear partial differential equations is given. An example of vibrational stabilization in a nonlinear situation (Benard instability) is described.     

Molecular beam study of CO chemisorption on alumina-supported Pd particles

The adsorption of carbon monoxide on small alumina-supported Pd particles and on a Pd(111) single crystal has been studied with a molecular beam techniques. The measured sticking coefficient shows that CO adsorbs on palladium surface according to precursor states. It is noted that a temperature dependent diffusion of gas molecules on the support influences the sticking probability of CO.     

How the design of an experiment influences the nonsensitiveness regions in models with variance components

Nonsensitiveness regions for estimators of linear functions, for confidence ellipsoids, for the level of a test of a linear hypothesis on parameters and for the value of the power function are investigated in a linear model with variance components.The influence of the design of an experiment on the nonsensitiveness regions mentioned is numerically demonstrated and discussed on an example.     

A new method for characterization of low grade gliomas using ultra low field magnetic resonance imaging

Low grade gliomas were studied with ultra low field magnetic resonance imaging (ULF MRI). The tumors exhibited high tissue contrast in both T₁ and T₂-weighted images as compared to normal brain tissue. Moreover they were sharply delineated towards the surrounding brain tissue. When compared with X-ray computed tomography the tumors were more readily detected and delineated by using ultra-low field magnetic imaging. A computerassisted classification procedure was used to define new regions of interest for relaxation time estimation. By using this procedure more accurate estimations of the T₁ and T₂ values were obtained.     

Nonlinear Impulse Target Problems under State Constraint: A Numerical Analysis Based on Viability Theory

We study the problem of reaching a target without leaving a prescribed set for controlled impulse dynamics. First, we provide a numerical procedure for the approximation of the set of initial conditions from which the objective can be met. Then we show that the minimum time function associated with this target problem can be approached by a sequence of value functions for suitable discrete-time systems. This can be deduced from the fact that the epigraph of the minimum time function is the set of initial conditions from which a target can be reached without leaving a constraint set for an auxiliary impulse system. In this case, the numerical procedure for the qualitative target problem can be simplified. We provide results for estimating the convergence rate of the simplified scheme.     

Comparative in vitro cytotoxicity assessment of some manufacturednanoparticulate materials characterized by transmissionelectron microscopy

A range of manufactured nanoparticulate materials, including Ag, TiO₂, Fe₂O₃, Al₂O₃, ZrO₂, Si₃N₄, and a range of carbonaceous nanoparticulate materials: single-wall and multi-wall carbon nanotube aggregates and aggregated nanoparticles of black carbon, as well as commercial (mineral grade) chrysotile asbestos nanotube aggregates, have been rigorously characterized by transmission electron microscopy. These nanoparticulate materials ranged in primary particle sizes from roughly 3 to 150 nm (except for the nanotube materials with lengths in excess of 15 μm). Aggregate sizes ranged from 25 nm to 20 μm. Comparative cytotoxicological assessment of these nanomaterials was performed utilizing a murine (lung) macrophage cell line. Considering the chrysotile asbestos to be a positive control, and assigning it a relative cytotoxicity index of unity (1.0), relative cytotoxicity indexes were observed as follows at concentrations of 5 μg/ml: 1.6 and ∼ 0.4 for Ag and TiO₂, respectively; 0.7–0.9 for the Fe₂O₃, Al₂O₃ and ZrO₂, 0.4 for the Si₃N₄, 0.8 for the black carbon, and 0.9 to 1.1 for the carbon nanotube aggregate samples. Observations of a cytotoxic response, nearly identical to that for chrysotile asbestos, for multi-wall carbon nanotube aggregates which very closely resemble anthropogenic multi-wall carbon nanotubes in the environment, raise some concern for potential health effects, especially for long-term exposure.