ABSTRACT
An analytical system based on ion-selective field effect transistors (ISFETs) with Ca(2+) ion selective photocurable membranes is developed to offer a semiautomatic analysis of serum calcium concentration of ruminants. Optimisation of ion-sensitive membrane composition containing different copolymerised plasticizers was performed to minimise the effect of a highly lipophilic samples on sensors characteristics. To improve the system reliability the set of calibration solutions and measurement sequence were also optimised. The system was used to determine total calcium concentration in bovine sera. The precision of the ion determination was higher than reported for double charge ions with a standard deviation of about 3-7%. It is shown that the presence of coagulant in blood serum samples does not affect the determined total calcium concentration.
Subject(s)
Calcium/blood , Cattle/blood , Acrylates/chemistry , Animals , Calcium Ionophores/chemistry , Cyclohexanes/chemistry , Decanoic Acids/chemistry , Female , Membranes, Artificial , Plasticizers/chemistry , Polyurethanes/chemistryABSTRACT
We report on the structural and electrical properties of Mn-doped ZnO/Al(2)O(3) nanostructures produced by the pulsed laser deposition technique. Grazing incidence small angle x-ray scattering (GISAXS) and Rutherford backscattering spectrometry revealed the multilayered structure in as-deposited samples. Annealing of the nanostructures was shown to promote the formation of nanocrystals embedded in the Al(2)O(3) matrix, as was evidenced by GISAXS and high resolution transmission microscopy. Particle-induced x-ray emission analysis showed a doping of 8 at.% Mn in ZnO. Grazing incidence x-ray diffraction and Raman spectroscopy demonstrated that the nanocrystals have the pure wurtzite ZnMnO crystalline phase. Resonant Raman scattering displayed an increase of intensity of the 1LO mode as well as broadening of the 2LO mode related to the size effect. Capacitance-voltage measurements showed carrier retention with a voltage shift higher than those reported for similar systems.
ABSTRACT
In this paper we report on the structural, optical and electrical properties of CdSe nanocrystals (NCs) embedded in silica matrix grown by the rf-magnetron sputtering technique with subsequent annealing under argon flux. Grazing incidence X-ray diffraction (GIXD), Photoluminescence (PL) and Raman spectroscopy, as well as current-voltage (I-V) measurements were used to characterize the CdSe NCs. The PL spectra of annealed samples demonstrate the presence of peaks in the range of 550-620 nm, indicating the quantum confinement effect in CdSe NCs. This quantum confinement effect in CdSe NCs was also confirmed by Raman spectroscopy. Finally, I-V behavior was explained by different concentrations and sizes of CdSe NCs.
ABSTRACT
Ge nanocrystals (NCs) embedded in aluminum oxide were grown by RF-magnetron sputtering. Raman, high resolution transmission electron microscopy (HRTEM), selected area diffraction (SAD), and X-ray diffraction (XRD) techniques confirmed good cristallinity of the NCs from samples annealed at 800 degrees C. The average NC size was estimated to be around 7 nm. Photoluminescence (PL) measurements show an emission related to the NCs. The temperature dependence of the PL confirms the confinement phenomenon in the Ge NCs.
ABSTRACT
In the present work a double ion sensor based on a laser scanned semiconductor transducer (LSST) for the simultaneous determination of K(+)- and Ca(2+)-ions in solutions has been developed. Specially elaborated ion-sensitive membrane compositions based on valinomycin and calcium ionophore calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (t-HDOPP-Ca) were deposited as separate layers on a silanized surface of the Si/SiO(2)/Si(3)N(4)-transducer. The proposed multi-sensor exhibits theoretical sensitivities and the detection limits of the sensor were found to be 2 x 10(-6) mol l(-1) for K(+) and 5 x 10(-6) mol l(-1) for Ca(2+). The elaborated double sensor is proposed for the first time as a prototype of a new type of multi-sensor systems for chemical analysis.
ABSTRACT
A micromanipulator is described to be designed for micro-operations on cells and for various cytological investigations using microelectrodes especially when cell scanning with inserted microinstrument is required. The baseplate of positioners is a light plate located on the microscope stage immediately. Thus, it is possible to do the following operations: to move the object in the field of vision of the microscope simultaneously with the inserted instrument; to insert several microinstruments into one cell; to make photometry of the cell with the inserted instrument by the scanning method. The positioners bear mechanical micromanipulator which ensures the moving of the instrument in three coordinates (8 mm lengthwise, 3 mm crosswise, and 4 mm in upright position). The micromanipulator can be employed with any type of biological microscopes and makes it possible to use objectives of high magnification (up to 100x). A little weight of the instrument (1 kg) makes it convenient to be used in the expedition.
Subject(s)
Cytophotometry/instrumentation , Micromanipulation/instrumentation , Animals , Cytological Techniques/instrumentation , Equipment DesignABSTRACT
A chamber is described with permanent solution flux aimed for in vivo cytophotometry (microscopy) of the nerve and muscle fibres, and for microelectrode registration of biopotential. Little size and construction peculiarities of the chamber make it possible to use objectives of middle and high magnification and to insert a microinstrument into the fiber.
