The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs.

The aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

Temperature dependence of Er³âº ionoluminescence and photoluminescence in Gd2O3:Bi nanopowder.

Ionoluminescence (IL) and photoluminescence (PL) of trivalent erbium ions (Er(3+)) in Gd2O3 nanopowder host activated with Bi(3+) ions has been studied in order to establish the link between changes in luminescent spectra and temperature of the sample material. IL measurements have been performed with H2 (+) 100 keV ion beam bombarding the target material for a few seconds, while PL spectra have been collected for temperatures ranging from 20 °C to 700 °C. The PL data was used as a reference in determining the temperature corresponding to IL spectra. The collected data enabled the definition of empirical formula based on the Boltzmann distribution, which allows the temperature to be determined with a maximum sensitivity of 9.7 × 10(-3) °C(-1). The analysis of the Er(3+) energy level structure in terms of tendency of the system to stay in thermal equilibrium, explained different behaviors of the line intensities. This work led to the conclusion that temperature changes during ion excitation can be easily defined with separately collected PL spectra. The final result, which is empirical formula describing dependence of fluorescence intensity ratio on temperature, raises the idea of an application of method in temperature control, during processes like ion implantation and some nuclear applications.

[Ebola virus disease]. / Ebola virus disease.

Ebola is one of the most virulent zoonotic RNA viruses causing in humans haemorrhagic fever with fatality ratio reaching 90%. During the outbreak of 2014 the number of deaths exceeded 8.000. The "imported" cases reported in Western Europe and USA highlighted the extreme risk of Ebola virus spreading outside the African countries. Thus, haemorrhagic fever outbreak is an international epidemiological problem, also due to the lack of approved prevention and therapeutic strategies. The editorial review article briefly summarizes current knowledge on Ebola virus disease epidemiology, etiology, pathogenesis, clinical presentation, diagnosis as well as possible prevention and treatment.

Pharmacotherapy of Ebola hemorrhagic fever: a brief review of current status and future perspectives.

The 2014 outbreak clearly showed that Ebola viruses (EBOV) remain a substantial threat for public health. The mainstay of management of patients with Ebola disease is isolation of patients and use of strict barrier nursing procedures; the present treatment strategies are mainly symptomatic and supportive (fluid resuscitation, antypyretics, antidiarrheal drugs). Currently, there is no approved therapy for Ebola hemorrhagic fever (EHF), however several advanced treatment options were tested in animal models (on non-human primates or rodents). They include use of both symptomatic (e.g. use of tissue factor inhibitors - rhNAPc2, rhAPC - to abolish coagulopathy) and specific antiviral approaches: e.g. monoclonal anti EBOV antibodies (ZMapp, MB-003), phosphorodiamidate morpholino oligomers (PMOs), liposomes containing siRNA (LNP-siRNA:TKM-Ebola) and small molecule inhibitors (e.g. BCX4430, favipiravir). The scope of this article is to briefly review the most promising therapeutics for EHF, based on the data coming from rare clinical reports, studies on animals and results from in vitro models.