Origin of unexpected defect engineered room-temperature ferromagnetism observed in tin-doped indium oxide (ITO) nanostructures (Nanowires, Nano-combs) and nanocrystalline thin films fabricated by pulsed laser deposition has been investigated. It is found that the ITO nanostructures prepared under argon environment exhibit strongest ferromagnetic signature as compared to that nanocrystalline thin films grown at oxygen. The evidence of singly ionized oxygen vacancy (V0+) defects, obtained from various spectroscopic measurements, suggests that such V0+ defects are mainly responsible for the intrinsic ferromagnetic ordering. The exchange interaction of the defects provides extensive opportunity to tune the room-temperature d0 ferromagnetism and optical properties of ITOs.

Background World Health Organization recommends Xpert MTB/RIF Ultra assay for diagnosing pulmonary tuberculosis (PTB) in children. Though stool is a potential alternative to respiratory specimens among children, the diagnostic performance of Xpert Ultra on stool is unknown. Thus, we assessed the diagnostic performance of Xpert Ultra on stool to diagnose PTB in children. Methods We conducted a cross-sectional study among consecutively recruited children (<15 years) with presumptive PTB admitted in four tertiary care hospitals of Dhaka, Bangladesh between January-2018 and April-2019. Single induced sputum and stool specimens were subjected to culture, Xpert and Xpert Ultra. We considered children as ‘bacteriologically confirmed on induced sputum’ if any tests performed on induced sputum was positive for Mycobacterium tuberculosis and ‘bacteriologically confirmed’ if Mycobacterium tuberculosis was detected on either induced sputum or stool. Results Of 447 children, 29 (6.5%) were ‘bacteriologically confirmed on induced sputum’ and 72 (16.1%) were ‘bacteriologically confirmed’. With ‘bacteriologically confirmed on induced sputum’ as a reference, the sensitivity and specificity of Xpert Ultra on stool was 58.6% and 88.1%, respectively. Whereas, Xpert on stool had sensitivity and specificity of 37.9% and 100.0%, respectively. Among ‘bacteriologically confirmed’, Xpert Ultra on stool was positive in 60 (83.3%) children, of which 48 (80.0%) had ‘trace call’. Conclusions In children, Xpert Ultra on stool has better sensitivity but lesser specificity than Xpert. A high proportion of Xpert Ultra positive on stool had ‘trace call’. Future longitudinal studies on clinical evolution are required to suggest on the management of children with ‘trace call’.

No abstract

Because of the presence of 3d transition metals in the Earth’s core, magnetism of these materials in their dense phases has been a topic of great interest. Theory predicts a dense face-centred-cubic phase of cobalt, which would be nonmagnetic. However, this dense nonmagnetic cobalt has not yet been observed. Recent investigations in thin film polycrystalline materials have shown the formation of compressive stress, which can increase the density of materials. We have discovered the existence of ultrathin superdense nonmagnetic cobalt layers in a polycrystalline cobalt thin film. The densities of these layers are about 1.2–1.4 times the normal density of Co. This has been revealed by X-ray reflectometry experiments, and corroborated by polarized neutron reflectometry (PNR) experiments. Transmission electron microscopy provides further evidence. The magnetic depth profile, obtained by PNR, shows that the superdense Co layers near the top of the film and at the film-substrate interface are nonmagnetic. The major part of the Co film has the usual density and magnetic moment. These results indicate the possibility of existence of nonmagnetic Co in the earth’s core under high pressure.

Hydrodesulfurization (HDS) of crude oil plays a vital role in the refining of petroleum products. With ever-increasing regulations restricting the allowable concentrations of sulfur in fuel, further research is required to produce more efficient and effective catalysts. Herein, we have synthesized carbon nanotube (CNT)-supported cobalt-molybdenum (CoMo) catalysts for HDS of dibenzothiophene (DBT) via Co-first and Mo-first sequential impregnation as well as co-impregnation. Spectroscopic analysis shows the formation of a CoMo catalyst with no free sulfided Co phase present. Additionally, CoMo catalysts are found to be predominantly single-layered nanocatalysts layered on the CNT support. Temperature-programmed reduction (TPR) measurements show differences in reducing temperature of the sulfided CoMo catalysts prepared by the different methods, but catalyst activities for HDS of DBT did not fully align with the TPR-predicted order. Thus, provided the reaction temperature is high enough, reducibility may not always be an adequate gauge of catalytic activity. Conversion of DBT was highest in Mo-first sequential impregnation (81.5%), followed by co-impregnation (64%) and Co-first sequential impregnation (60%) on a CNT support. While these results contrast with some others regarding the order of impregnation, we propose that the preferred impregnation order is actually support-dependent, rather than an absolute quality.