Worldwide Effects of Coronavirus Disease Pandemic on Tuberculosis Services, January–April 2020

Coronavirus disease has disrupted tuberculosis services globally. Data from 33 centers in 16 countries on 5 continents showed that attendance at tuberculosis centers was lower during the first 4 months of the pandemic in 2020 than for the same period in 2019. Resources are needed to ensure tuberculosis care continuity during the pandemic

Conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over Au-based catalysts: Optimization of active phase and metal-support interaction

In the present work, a series of Au- and Au-Cu-containing catalysts based on different carriers such as TiO2 and CeO2 were studied with a view to increasing the activity and selectivity in 5-hydroxymethylfurfural oxidation by optimizing the interaction both between the metals and with the support. The results obtained demonstrated the high activity in HMF oxidation of gold supported on ceria and titania. Nevertheless, although the particle size of gold on both supports was comparable, Au/CeO2 showed significantly higher activity than Au/TiO2, thus corroborating the theory that not only the gold particle size, but the support also, plays a key role in HMF oxidation in the aqueous phase. Indeed, pre-made uniform nanoparticles, used for catalyst preparation, were surface-bound by poly(N-vinyl-2-pyrrolidone) - the stabilizer used during nanoparticle synthesis - whose presence proved to prevent the interaction of active phases with CeO2, while worsening the catalytic activity of both monometallic and bimetallic systems. The pre-treatment of the prepared catalysts was necessary to activate the materials, by maximizing the contact between the metal and the support and thus suggesting an important role of the ceria defects on 5-hydroxymethylfurfural oxidation to 2,5-furandicarboxylic acid

Microstructure and phase evolution of micronized ceramic colorants from a pilot plant for inks production

The advent of inkjet printing as digital decoration of ceramic materials has irreversibly modified the industrial decoration technology, imposing companies to change the colorant production process. The inkjet application requires micronized particles in the ultrafine particle size range (smaller than 1 μm). Particles size reduction of ceramic colorants is performed by a high-energy comminution process in wet-operated bead mills, affecting colorants properties. Since a deep knowledge of milling-induced microstructural changes is still lacking, the micronization effects on a set of five industrial ceramic colorants are thoughtfully investigated in this work by simulating the industrial process at a pilot plant. Particle size distribution and energy consumption are monitored during the comminution process. The compositional (including crystallite size and microstrain analysis of the main phases) and morphological variation of four ceramic pigments (yellow zircon, brown spinel, pink malayaite, and green eskolaite) and one dye (blue olivine) is investigated by XRPD (Rietveld method) and SEM analyses. The analytical approach combined with a physical/semiempirical modelling of the colorants elastic features versus the energy demand for particle reduction has yielded details on the nature of the micronizationinduced microstructural changes in ceramic colorants. Specifically, the comminution efficiency as well as the crystalline phase stability are related to the intrinsic properties of each colorant. Brittle breakage rather than plastic deformation on comminution are also system dependent. When an euhedral to subhedral crystal habit is maintained a brittle fracture is preserved throughout the comminution progress, while the formation of flake-like particles and particle agglomeration are strong evidences of plastic deformation. The last evidence deals with the material elastic features. Materials with high bulk modulus convert the grinding energy to lattice defects that lead to particle breakage by brittle fractures, while materials with lower bulk modulus convert/dissipate part of the supplied energy in plastic deformations, drastically decreasing the comminution process efficiency

Chemical, morphological and mechanical study of the ageing of textile flax fibers from 17th/18th-century paintings on canvas

International audienceA variety of techniques were used to investigate flax yarns sampled from four selected Italian paintings on canvas dated between the 17th and 18th centuries and compare them with a modern flax yarn. The goal was to establish their state of preservation and highlight the critical issues thanks to a combined approach that used SEM, atomic force microscopy, nanoindentation, nuclear magnetic resonance, second harmonic generation imaging microscopy and FTIR spectroscopy. The condition of the flax fibres was assessed, and the results showed that two of the four canvases were in a generally good state of preservation, while the other two exhibited signs of biological attack and brittleness due to a previous relining intervention

Effect of micronisation on colour and optical properties of ceramic colourants for inkjet printing

The advent of inkjet printing (IJP) as the main used decoration technique for ceramic products has changed the technological requirements for pigments and the way they are obtained. To meet IJP and durability requirements, it is necessary to micronise the colourants to achieve particles smaller than 1 μm (median particle diameter d50 ∼300 nm). The high-energy milling process induces microstructural changes that affect the colour properties. In order to understand the effect of particle size reduction on chromatic properties, an in-depth study was carried out by simulating the industrial milling process on a pilot scale. The effect of micronisation was investigated for four ceramic pigments (yellow zircon, brown spinel, pink malayaite, and green eskolaite) and one dye (blue olivine) by UV–vis–NIR optical spectroscopy (DRS), chromatic coordinates and XRPD analyses (Rietveld method). This study was carried out on the colourants both as they were and mixed with glass, reproducing the industrial firing process. The results obtained led to the definition of the main aspects responsible for the colour evolution derived from the milling process