Effects of gamma radiation on the electrical properties of InAs/InGaAs quantum dot-based laser structures grown on GaAs and Si substrates by molecular beam epitaxy.

This study investigates the impact of gamma radiation on the electrical properties of InAs/InGaAs quantum dot-based laser structures grown on both GaAs (Sample A) and Si (Sample B) substrates using molecular beam epitaxy. The research explores the electrical characteristics of the lasers before and after being exposed to gamma radiation employing current-voltage (I-V), capacitance-voltage (C-V), deep level transient spectroscopy (DLTS) and Laplace DLTS techniques. The results show that the electrical properties of the lasers change due to gamma radiation exposure, and the extent of the change depends on the substrate used for growth. The I-V results revealed that the ideality factor (n) and built-in voltage were increased in Sample A and Sample B after radiation. Nonetheless, the series resistance (Rs) at room temperature decreased in both samples after radiation. Overall, this study provides valuable insights into the effects of gamma radiation on the electrical properties of InAs/InGaAs quantum dot lasers and highlights the importance of considering substrate materials in the design of radiation-hardened electronic devices.

Synthesis and photothermal performance of non-stoichiometric molybdenum oxide (MoO3-x) prepared by gamma radiation.

This work reports the interaction of γ-rays with MoO3 in several solvents to obtain non-stoichiometric (sub-oxide) MoO3-x through a one-pot synthesis. The effect of different doses of γ-radiation (30-90 kGy) with different protic solvents (water, N,N-dimethylformamide and formic acid) was investigated. Structural modifications were characterized by X-ray diffractometry and scanning electron microscopy while optical properties were investigated by UV-Vis spectroscopy. The analysis of the highly intense (020), (040) and (060) diffraction peaks suggests that there is a reduction in water and formic acid allowing the formation of MoO3-x nanosheets. Additionally, the photothermal response of MoO3-x obtained under different conditions was characterized, and a possible mechanism to explain the interaction of γ-rays with solvents and the oxide structure by oxidative/reductive processes in the solution was proposed.

Polyvinyl alcohol-glutaraldehyde as solid-phase in ELISA for schistosomiasis

Preparaçöes antigenicas soluveis de Schistosoma mansoni adulto (SWAP) fixadas covalentemente em discos de polivinil alcool-glutaraldeido foram usadas em teste de ELISA. As melhores condiçöes para o ensaio foram estabelecidas e foi encontrado que uma quantidade mínima de antigeno, em torno de 1,5 ug e necessária. Comparaçäo entre este procedimento e o de ELISA convencional foi estabelecida. Um metodo seguro de imobilizaçäo do antigeno foi alcançado e os baixos preços dos reagentes empregados säo economicamente atraentes...