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Soda lime silicate oxide glasses are studied to per-form coloration thanks to gold nanoparticles' crystallization. This precipitation is conducted by chemical reduction of gold ions with stannous or antimony oxides as reducing agents. A control of the rendered coloration between blank to red shades has been obtained using [Sb.sub.2][O.sub.3] agent and appropriate thermal treatments. The glasses remain colorless while heating up to 450 °C. Structural glasses evolution is studied by MAS NMR spectroscopy of [.sup.29]Si and [.sup.23]Na nuclei to investigate the silicate network polymerization change and the modification of sodium/oxygen bond length versus nucleation state and growth of Au nanoparticles. A clear decrease of the [Q.sup.2] species part is observed with nanoparticles growth confirmed by the evolution of chemical shift for [.sup.23]Na resonance. A slight net-work polymerization is then showed independently of the only thermal treatment. This structural change could be induced by the antimony oxidation and change towards higher coordinations. Finally, the glasses chemical durability has been studied by leaching tests and shows lower alteration for colored glass. The optical spectroscopy applied to colored glasses has given rise to plasmon resonance phenomena at around 600 nm which is the typical surface plasmon resonance of gold for a refractive medium index of 1.5, with a shift of the resonance towards the higher wavelengths with increasing thermal treatment temperature. This shift is modelized by Drude and MIE approaches and confirms the trend observed by UV-visible measurement with an increasing absorption at the SPR correlated to a typical Ostwald growth mechanism according to the increase of the annealing temperature. Keywords Silicate glass-ceramic. Gold nanoparticles. Plasmonic effect. Drude and Mie Model. Chemical durability. MAS NMR spectroscopy. Structure, Introduction Cadmium sulfoselenide is currently used as pigment for red glass making (1), (2). According to the cadmium toxicity, another common way to elaborate ruby glasses is the addition of [...]

The concentration dependence of the phase stability, half-metallicity, thermal and magnetic properties of Fe2MnxNi1−xSi (0 ≤ x ≤ 1) Heusler alloys in two structures, Cu2MnAl (Fm3m) and Hg2TiCu (F43m), were investigated at the ab initio level using density functional theory. The exchange-correlation term was assessed using local spin density (LSDA) and generalized gradient approximation (GGA) along with Hubbard-U (U) corrections. Spin-polarized electronic band structure calculations for Fe2MnxNi1−xSi (0 ≤ x ≤ 1) alloys in their Cu2MnAl- and Hg2TiCu-structure have been carried out. These results indicate that the Hg2CuTi-type structure is more stable than the Cu2MnAl-type structure with increasing Mn content, from x = 0 to 0.25 using LSDA. No significant differences were observed using LSDA + U over GGA. The full Heusler compounds Fe2MnxNi1−xSi (0 ≤ x ≤ 1) are half metals in the Cu2MnAl-type structure for x = 0.75 and x = 1, and behave like a metal in the CuHg2Ti-type. The minority bands exhibit a band gap of about 0.11 (0.56) eV for Fe2Mn0.75Ni0.25Si using GGA (LSDA + U). Using the GGA scheme, the obtained band energy was smaller than that obtained by using the LSDA + U approach. These results clearly show that the lattice parameter, bulk modulus and total magnetic moment vary quadratically with Mn doping. The main contribution to the total magnetic moment comes from Mn or Fe atoms in B sites in both types of structures. The total magnetic moment of Fe2MnxNi1−xSi (0 ≤ x ≤ 1) alloys is typically in the range of 2-3 μB in the Cu2MnAl-Type and 3-4 μB in Hg2TiCu-Type per formula unit and consists of an average of 2 μB per Mn atom and less than 1 μB per Fe atom in the Cu2MnAl-Type, and an average of 2 μB per Mn atom and around 1 μB per Fe atom in the B site Hg2TiCu-Type. Using the quasi-harmonic Debye model, the concentration and temperature effects on the unit cell volume, thermal expansion coefficient, bulk modulus, the Debye temperature and heat capacity, for Fe2MnxNi1−xSi (0 ≤ x ≤ 1) Heusler alloys are investigated and analysed. [ABSTRACT FROM AUTHOR]

Aim: Assess the impact of stress and Burnout syndrome on health workers during the COVID-19 pandemic., Method: A survey through an online questionnaire was conducted among health personnel, completed with a paper questionnaire collection, Information was collected on demographics, COVID-19 unit activity, the Burnout syndrome calculated by the Maslach Burnout Inventory scale, is defined by high levels of exhaustion and depersonalization when the total score reaches 30 and 12 points respectively and by a low level of professional accomplishment from a total score of 40, the level of stress perception is calculated by the post-traumatic stress scale, whose threshold is equal or greater than 44 points., Results: 345 responses were included concerning doctors, paramedics and technical-administrative staff working in an Algerian health facility between October 2021 and January 2022. Prevalence rates were 44.3% for burnout, 30.1% for depersonalization and 56.2% for low achievement, the prevalence of Post-Traumatic Stress Disorder was 38.6% of study participants. Analysis of risk factors among caregivers (physicians and paramedics) showed that burnout was related to age (p=0.041), the notion of the workplace in a dedicated COVID-19 patient unit (p=0.009) and the occurrence of death in the health professional's entourage (p=0,015). The occurrence of a death event among those around caregivers is a risk factor for post-traumatic stress syndrome with a OR=2.02, IC 95% [1,17-3,47]., Conclusion: Knowledge of the impact of COVID-19 on health professionals is an important element in maintaining their mental health and is a key consideration when managing health crises.