Synthesis and characterization of core–shell magnetic molecularly imprinted polymer nanoparticles for selective extraction of tizanidine in human plasma

In this study, simple, effective and general processes were used for the synthesis of a new nano-molecularly imprinted polymers (MIPs) layer on magnetic Fe₃O₄ nanoparticles (NPs) with uniform core–shell structure by combining surface imprinting and nanotechniques. The first step for the synthesis of magnetic NPs was co-precipitation of Fe²⁺ and Fe³⁺ in an ammonia solution. Then, an SiO₂ shell was coated on the magnetic core with the Stöber method. Subsequently, the C=C groups were grafted onto the silica-modified Fe₃O₄ surface by 3-(trimethoxysilyl) propyl methacrylate. Finally, MIPs films were formed on the surface of Fe₃O₄@SiO₂ by the copolymerization of C=C end groups with methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), 2,2-azobisisobutyronitrile (initiator) and tizanidine (template molecule). The products were characterized using techniques that included Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), UV spectrophotometry, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Measurement of tizanidine through use of the core–shell magnetic molecularly imprinted polymers nanoparticles (MMIPs-NPs) in human plasma samples compared to the paracetamol showed that the synthesized nanosized MMIP for tizanidine has acted selectively.     

Assessment of approximate balance equation transport models used for submicron silicon device modelling

The common approximations found in literature for the balance equation method used for non-stationary submicron device simulation are presented and discussed. To assess different approximations, the full balance equation model is solved numerically solved for the n⁺-i-n⁺ submicron silicon structure where nonstationary transport effects eventually take place. The results obtained from the derived approximate models applied to the same silicon structure are compared with those obtained from the full model. In all cases, empirical formulae for momentum and energy relaxation times are used to clarify only the effect of approximations on the simulation results.     

Hydration behaviour of synthetic saponite at variable relative humidity

Hydration behaviour of synthetic saponite was examined by X-ray powder diffraction simulation at various relative humidities (RH). The basal spacing of the Ca-saponite increased stepwise with increase in RH. The (00l) reflections observed reflect single or dual hydration states of smectite. Quasi-rational, intermediate, or asymmetrical reflections were observed for all XRD patterns and reflecting heterogeneity of the samples, especially along the transition between two hydration states.     

Simple phase meter with lead/lag indication

A simple and inexpensive circuit for measuring the phase angle difference between two waves with lead/lag indication is described. The proposed circuit may be adopted in the laboratory as an attachment to a commercially available analogue/ digital multimeter to measure the phase difference. The response is linear over a range 0 to + 180^° and is unaffected by the input frequencies in the range 6 Hz–1.2 kHz. For distorted waveforms, the paper also gives a simple scheme to measure the displacement angle which in turn suggests its use in a high-power-factor self-compensated alternating voltage controller.     

COMPOSITION OF WASHED MECHANICALLY SEPARATED AND HAND BONED BEEF

Washed mechanically separated (MS) beef and washed hand boned (HB) beef samples were prepared with an emulsifier or silent cutter. Higher yields of washed beef were obtained with the silent cutter, but differences in composition were small. Bone particle size in MS beef was reduced with the emulsifier and the silent cutter. Washed MS beef contained more iron, fat and cholesterol than washed HB beef. Collagen content of washed MS beef was about twice as high (P < 0.05) as that of washed HB beef. The major proteins in all washed beef lots were myosin and actin. Minor differences in amino acids and fatty acids between MS beef and HP beef existed. Binding properties of washed beef and fish surimi in restructured beef steaks were similar. Overall, washed MS and HB beef are low in fat and high in protein quality and have the potential to replace much of the salt in restructured beef products.     

Pore Structure of Calcium Silicate Hydrate in Hydrated Tricalcium Silicate

Adsorption of N₂ and water vapor was studied in completely hydrated tricalcium silicate and in fully hydrated tricalcium silicate from which Ca(OH)₂ had been extracted. Compared with results obtained using N₂, water vapor adsorption led to increased values for small-pore volume, peak shifts to smaller sizes, and decreased values for large-pore volume. Marked hysteresis was observed in the case of water vapor adsorption; the resorption branch apparently represents the true pore structure. Extraction of Ca(OH)₂ from the paste increased the calculated volume of small pores strikingly, suggesting that adsorption is hindered by Ca(OH)₂; this tendency is more obvious in water vapor adsorption. The adsorption measurements indicate the existence of two kinds of pores, i.e. a wider intergel-particle pore and a smaller pore existing within the gel particle. The latter pore was further classified into intercrystallite and intracrystallite pores.     

ESR Study of Devitrification Processes

The radiation-induced ESR centers in glasses with different Ti concentrations were studied to elucidate crystallization processes in the glass. The parameters of the induced ESR absorption associated with the T ₂ center were investigated systematically as a function of heat treatment. The induced T ₂ centers in the glasses containing small concentrations of Ti characteristically decreased in intensity as nucleation began and disappeared completely in devitrified samples. A mechanism is proposed for the destruction of the T ₂ center as nucleation proceeds to crystallization. Supporting X-ray diffraction evidence is given. The systematic decrease in the ESR intensity of this radiation-induced center provides a means of monitoring devitrification processes in glasses.