Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Delta, Y144Delta, and LLA241/243Delta. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers

Effects of electrolyte and Ti layers on static and dynamic friction of anodized alumina

Static friction is important for many non-lubricated surfaces, especially when friction is intermittent. Coefficients of Friction (COF) were evaluated on industrial aluminum alloys 1050 and 6082, which were freshly anodized in sulfuric/oxalic or phosphoric acid electrolytes to 60 μm coating thickness. Hard anodizing significantly reduced COF. Under 10 N load friction trends were nearly identical despite sliding velocity variation from 0.02 to 0.5 cm/s, while 1 N load led to higher static COF. Magnetron sputtering was used to deposit Ti layers. Static COF went down from over 0.4 to ~0.2 in 16 nm and 75 nm thick layers, while that of 2.3 μm had no positive effect. Dynamic COF was also similarly reduced, suggesting possible industrial applications

Material processing with ultra-short pulse lasers working in 2μm wavelength range

International audienc

Laser-induced spatially-selective tailoring of high-index dielectric metasurfaces

Optically resonant high-index dielectric metasurfaces featuring Mie-type electric and magnetic resonances are usually fabricated by means of planar technologies, which limit the degrees of freedom in tunability and scalability of the fabricated systems. Therefore, we propose a complimentary post-processing technique based on ultrashort (≤ 10 ps) laser pulses. The process involves thermal effects: crystallization and reshaping, while the heat is localized by a high-precision positioning of the focused laser beam. Moreover, for the first time, the resonant behavior of dielectric metasurface elements is exploited to engineer a specific absorption profile, which leads to a spatially-selective heating and a customized modification. Such technique has the potential to reduce the complexity in the fabrication of non-uniform metasurface-based optical elements. Two distinct cases, a spatial pixelation of a large-scale metasurface and a height modification of metasurface elements, are explicitly demonstrated