Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

A Microstructural and Wear Resistance Study of Stainless Steel-Ag Coatings Produced through Magnetron Sputtering

This paper presents a study of the tribological properties of stainless steel coatings with varying Ag contents, deposited via magnetron sputtering. The growth of the coatings was done in Ar and Ar + N2 atmospheres in order to change the crystalline phase in the coating. The analysis of the chemical composition was performed using energy-dispersive X-ray spectroscopy (EDS) and the structural analysis was performed via X-ray diffraction (XRD). The adhesive wear resistance and the friction coefficient were evaluated using the ball-on-disk test with a ball of alumina. The coatings’ adhesion was measured with a scratch tester and the mechanical properties were evaluated with a nanoindenter. The morphology of the films and the wear track were characterized via scanning electron microscopy (SEM). By means of XRD, phases corresponding to the body-centred cubic (BCC) structure were found for the coatings deposited in an inert atmosphere and face-centred cubic (FCC) for those deposited in a reactive atmosphere. A more compact morphology was observed in coatings with a higher silver content. The values of the hardness increased with an increase in the silver content and the presence of nitrogen in the coatings. In the wear traces, mainly mechanisms of oxidative and adhesive wear and plastic deformation were found. The coefficient of friction decreased with an increase of silver in the coatings, whereas the wear rate decreased

Interlocked host anion recognition by an indolocarbazole-containing [2]rotaxane

The design, synthesis, structure, and anion-binding properties of the first indolocarbazole-containing interlocked structure are described. The novel [2]rotaxane molecular structure incorporates a neutral indolocarbazole-containing axle component which is encircled by a tetracationic macrocycle functionalized with an isophthalamide anion recognition motif. (1)H NMR and UV-visible spectroscopies and X-ray crystallography demonstrated the importance of pi-donor-acceptor, CH...pi, and electrostatic interactions in the assembly of pseudorotaxanes between the electron-deficient tetracationic macrocycle and a series of pi-electron-rich indolocarbazole derivatives. Subsequent urethane stoppering of one of these complexes afforded a [2]rotaxane, which was shown by (1)H NMR spectroscopic titration experiments to exhibit enhanced chloride and bromide anion recognition compared to its non-interlocked components. Computational molecular dynamics simulations provide further insight into the mechanism and structural nature of the anion recognition process, confirming it to involve cooperative hydrogen-bond donation from both macrocycle and indolocarbazole components of the rotaxane. The observed selectivity of the [2]rotaxane for chloride is interpreted in terms of its unique interlocked binding cavity, defined by the macrocycle isophthalamide and indolocarbazole N-H protons, which is complementary in size and shape to this halide guest

XX Semana de la Enseñanza de la Física

25 a 29 de septiembre de 2017Facultad de Ciencias y EducaciónProyecto Curricular de Licenciatura en FísicaUniversidad Distrital Francisco José de Calda