The effect of 8.6·1017n/cm2 fast neutron irradiation on the magnetic susceptibility and magnetoresistance of Si whiskers with impurity concentration near metal–insulator transition (MIT) has been ...studied. Neutron irradiated specimens with boron concentration away of MIT are mainly diamagnetic with a small amount of paramagnetic centers originated from dangling bonds on the whisker surface. It has been established that at temperatures near 4.2K, a significant contribution to the conductivity is made by light charge carriers of low concentration but with high mobility. The as grown whiskers with impurity concentration correspondent to MIT showed hysteresis loops in magnetization at temperature of liquid helium. Besides hysteresis loops in magnetoresistance was observed for whiskers under compression stress at low temperature up to 7K. The possible reason of the effect can be magnetic interaction between impurities centers in subsurface region of the whisker with the orbital moment of dangle bounds in the whisker core–shell interstices.
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•Neutron irradiation influence on magnetic susceptibility of Si whiskers is studied.•Neutron irradiated Si whiskers with boron concentration away of MIT are diamagnetic.•Whiskers in the vicinity to MIT showed hysteresis loops in magnetoresistance.•Whiskers in the vicinity to MIT showed hysteresis loops in magnetic susceptibility.
In the present study, a new Gal/GalNAc specific lectin from the mussel Mytilus trossulus (designated as MTL) was identified, and its expression levels, both in tissues and toward pathogen ...stimulation, were then characterized. The MTL primary structure was determined via cDNA sequencing. Deduced sequence of 150 amino acid residues showed 89% similarity to lectins from the mussels Crenomytilus grayanus and Mytilus galloprovincialis that were the first members of a new family of zoolectins. The results indicated that the MTL might be involved in immune response toward pathogen infection, and it might perform different recognition specificity toward bacteria or fungi.
•The amino acid sequence a lectin from the mussel Mytilus trossulus was determined.•The lectin is a member of a novel lectin family.•It was shown that the lectin is a β/α-protein.•The lectin exhibits the antibacterial and antifungal activity.
The features of the current-voltage characteristics of LEDs obtained on the basis of GaP-GaAsP solid solutions are considered. The results of studies of the effect of electron irradiation (E = 2 MeV, ...F = 3 · 1014 ÷ 2.6 · 1016 cm-2) on the main electrophysical parameters of GaAs1-xPx diodes (x = 0.85 – yellow, x = 0.45 – orange) are given. The increase of differential resistance, the series resistance of the base, and barrier potential are revealed. The processes of recovery of the investigated quantities during isochronous annealing are analyzed, the mechanisms of degradation-recovery phenomena are discussed.
In the present study, a new Gal/GalNAc specific lectin from the mussel Mytilus trossulus (designated as MTL) was identified, and its expression levels, both in tissues and toward pathogen ...stimulation, were then characterized. The MTL primary structure was determined via cDNA sequencing. Deduced sequence of 150 amino acid residues showed 89% similarity to lectins from the mussels Crenomytilus grayanus and Mytilus galloprovincialis that were the first members of a new family of zoolectins. The results indicated that the MTL might be involved in immune response toward pathogen infection, and it might perform different recognition specificity toward bacteria or fungi.
Lectins (carbohydrate-binding proteins) are well known to actively participate in the defense functions of vertebrates and invertebrates where they play an important role in the recognition of ...foreign particles. In this study, we investigated of in vitro antifungal activity of lectin from the mussel Crenomytilus grayanus (CGL). Enzyme-linked immunosorbent assay indicated that CGL was predominantly detectable in tissues of mantle and to a lesser degree in the tissues of muscle, hepatopancreas, gill and hemocytes. After challenged by Pichia pastoris the level of CGL was upregulated and reached the maximum level at 12 h post challenge and recovered to the original level at 24 h. The lectin was capable of inhibiting the germination of spores and hyphal growth in the fungi. All these results indicated that CGL is involved in the innate immune response in mollusc animals.
•Antifungal activity of lectin from the mussel Crenomytilus grayanus was determined.•CGL exhibited the highest expression in mantle.•The level of CGL was upregulated after Pichia pastoris challenge.•CGL was able to inhibit the in vitro growth of the fungi.•The lectin plays defensive role in the mollusk.
Electrical characteristics of red and green GaP light diodes irradiated by fast electrons and neutrons were studied. It has been found that S-type current–voltage curves, measured in current ...generator mode at low-temperature, show presence of fine structure. The mechanism of negative differential resistance formation and influence of radiation on current transport and relaxation mechanisms have been studied. Estimation of the effective cross-section for electron capture by recombination levels and its changes under irradiation were obtained from experimental data. Detailed study of radiation modification of GaP light diode parameters makes it possible to propose these devices as high sensitive sensors of gamma rays and electrons.
Semiconductor detectors for neutron flux measurements Litovchenko, P.G.; Wahl, W.; Bisello, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Silicon detectors with
235U converter for neutron flux measurements over a wide energy range (from thermal up to epithemal neutrons) have been developed. The surface-barrier detectors with plastic ...converters were developed for fast neutron detection.
Silicon detectors for γ-ray and β-spectroscopy Litovchenko, P.G.; Wahl, W.; Bisello, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2003, Letnik:
512, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Large active volume Si(Li) detectors were successfully developed for γ-ray spectrometry at room temperature that show a sufficient efficiency and an energy resolution that is better than ...scintillation detectors. The higher efficiency of the proposed detectors with respect to normal silicon diodes is achieved by increasing the active volume. For this purpose special attention is given to the selection of the initial material which has to show homogeneous electro-physical parameters, low concentration of oxygen impurities and high structural perfection. The technique of using lithium ions is used as these drift into large depths and hence the profile of the impurity distribution is optimized.
Radiation hardness of silicon detectors based on pre-irradiated silicon Litovchenko, P.G.; Groza, A.A.; Lastovetsky, V.F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2006, Letnik:
568, Številka:
1
Journal Article
Recenzirano
Radiation hardness of planar detectors processed from pre-irradiated and thermo-annealed n-type FZ silicon substrates, and standard FZ as a reference, was studied. The high purity n-Si wafers with ...carrier concentration 4.8×10
11
cm
−3 were pre-irradiated in Kiev's nuclear research reactor by fast neutrons to fluence of about 10
16
neutrons/cm
2 and thermo-annealed at a temperature of about 850
°C. Silicon diodes were fabricated from standard and pre-irradiated silicon substrates by IRST (Italy). All diodes were subsequently irradiated by fast neutrons at Kiev and Ljubljana nuclear reactors. The dependence of the effective doping concentration as a function of fluence (
N
eff
=f(
Φ)) was measured for reference and pre-irradiated diodes. Pre-irradiation of silicon improves the radiation hardness by decreasing the acceptor introduction rate (
β), thus mitigating the depletion voltage (
V
dep) increase. In particular,
β in reference samples is about 0.017
cm
−1, and for pre-irradiated samples is about 0.008
cm
−1. Therefore, the method of preliminary irradiation can be useful to increase the radiation hardness of silicon devices to be used as sensors or detectors in harsh radiation environments.
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