An integrated device for fast and sensitive immunosuppressant detection

The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more than one analyte with replicate measurements. The device is equipped with a microfluidic system, which provides sample mixing with the necessary chemicals and pumping samples, reagents and buffers into the measurement chip, and with integrated thin film amorphous silicon photodiodes for the fluorescence detection. Submicrometric fluorescent magnetic particles are used as support in the immunoassay in order to improve the efficiency of the assay. In particular, the magnetic feature is used to concentrate the antibody onto the sensing layer leading to a much faster implementation of the assay, while the fluorescent feature is used to increase the optical signal leading to a larger optical dynamic change and consequently a better sensitivity and a lower limit of detection. The design and development of the whole integrated optical device are here illustrated. In addition, detection of mycophenolic acid and cyclosporine A in spiked solutions and in microdialysate samples from patient blood with the implemented device are reported. Graphical abstract

Crystal growth and physical properties of an antiferromagnetic molecule: trans-dibromidotetrakis(acetonitrile)chromium(III) tribromide, [CrBr2(NCCH3)4](Br3)

The synthesis, crystal structure determination, magnetic properties and bonding interaction analysis of a novel 3d transition-metal complex, [CrBr2(NCCH3)4](Br3), are reported. Single-crystal X-ray diffraction results show that [CrBr2(NCCH3)4](Br3) crystallizes in space group C2/m (No. 12) with a symmetric tribromide anion and the powder X-ray diffraction results show the high purity of the material specimen. X-ray photoelectron studies with a combination of magnetic measurements demonstrate that Cr adopts the 3+ oxidation state. Based on the Curie–Weiss analysis of magnetic susceptibility data, the Néel temperature is found to be around 2.2 K and the effective moment (μeff) of Cr3+ in [CrBr2(NCCH3)4](Br3) is ∼3.8 µB, which agrees with the theoretical value for Cr3+. The direct current magnetic susceptibility of the molecule shows a broad maximum at ∼2.3 K, which is consistent with the theoretical Néel temperature. The maximum temperature, however, shows no clear frequency dependence. Combined with the observed upturn in heat capacity below 2.3 K and the corresponding field dependence, it is speculated that the low-temperature magnetic feature of a broad transition in [CrBr2(NCCH3)4](Br3) could originate from a crossover from high spin to low spin for the split d orbital level low-lying states rather than a short-range ordering solely; this is also supported by the molecular orbital diagram obtained from theoretical calculations.

Relationship between magnetic field properties and statistical flow using numerical simulation and magnetic feature tracking on solar photosphere

ABSTRACT We perform radiative magnetohydrodynamic calculations for the solar-quiet region to investigate the dependence of statistical flow on magnetic properties and the three-dimensional structure of magnetic patches in the presence of large-scale flow that mimics differential rotation. It has been confirmed that strong magnetic field patches move faster in the longitudinal direction at the solar surface. Consequently, strong magnetic patches penetrate deeper into the solar interior. The motion of the deep-rooted magnetic patches is influenced by the faster differential rotation in the deeper layer. In this study, we perform realistic radiative magnetohydrodynamic calculations using r2d2 code to validate that stronger patches have deeper roots. We also add large-scale flow to mimic the differential rotation. The magnetic patches are automatically detected and tracked, and we evaluate the depth of 30 000 magnetic patches. The velocities of 2.9 million magnetic patches are then measured at the photosphere. We obtain the dependence of these values on the magnetic properties, such as field strength and flux. Our results confirm that strong magnetic patches tend to show deeper roots and faster movement, and we compare our results with observations using the point spread function of instruments at the Hinode and Solar Dynamics Observatory (SDO). Our result is quantitatively consistent with previous observational results of the SDO.

Two-Phase Co–Cu Thin Films with Size Distribution of Ferromagnetic Nanostructures Optimum for Giant Magneto Resistance

New thin-film microstructure, with a homogeneous distribution of a crystalized one phase Co-rich magnetic nanoparticles, embedded in a Cu-rich continuous paramagnetic matrix was obtained. This structure has many of the characteristics deemed optimal for Giant Magneto Resistance (GMR). These characteristics are; mean free path of the electrons in the matrix, granules/matrix interface roughness, the ferromagnetic concentration of the magnetic granules, and most importantly, the size distribution of the granules. This microstructure was created in Co-93at%Cu thin film, through spinodal decomposition after a short time of aging that reached equilibrium by a growth and coarsening process. Main goal of the present work was the enhancement of the microstructure in order to pinpoint the optimum microstructural and magnetic feature that improves the GMR sensitivity and stability in granular materials. Accordingly, Structural evolution of the thin films was controlled by the annealing time and temperature. Four-probe-technique was utilized to measure the GMR properties. GMR curve for a sample annealed at 150 °C was found to be stable and saturated even at low magnetic field (<5 kOe). Microstructural evolution and compositional analysis of the thin film was investigated using in-situ transmission electron microscopy (TEM) and the energy dispersive X-ray spectrometer (EDXS).