H2 detection mechanism in chemoresistive sensor based on low-cost synthesized WO3 nanorods

Abstract Nanostructured WO3 represents a promising material for fast and reliable molecular hydrogen detection through chemo-resistive effect. Here, an extended experimental investigation of WO3-H2 interaction is presented and modeled. A powder of WO3 nanorods (400 nm long, 50 nm large) is produced by hydrothermal technique and drop casted on Pt interdigitated electrode. H2 sensing tests at different concentrations (2000–50,000 ppm) and temperatures (250–400 °C) are reported. Scanning Electron Microscopy (SEM), X-ray Diffraction analysis (XRD), and electrical measurements were performed. The response and recovery kinetics of H2 sensing are carefully described by using a two-isotherms Langmuir model, and kinetics barriers for WO3-H2 interaction are evaluated. Two microscopic processes lead to gas detection. A fast process (shorter than 4 s) is attributed to H2 interaction with adsorbed oxygen at WO3 nanorods surface. A slow process (20–1000 s), with activation energy of 0.46 eV, is attributed to oxygen vacancy generation in WO3. H intercalation in WO3 is ruled out. The recovery of WO3 after H2 exposure is also modeled. The chemo-resistive effect leading to H2 sensing by WO3 is explained through the above processes, whose kinetic barriers have been quantified. These data open the route for the development of fast, sensitive, and low-temperature operating H2 sensors based on WO3

High intrinsic activity of the oxygen evolution reaction in low-cost NiO nanowall electrocatalysts

NiO nanowalls grown by low-cost chemical bath deposition and thermal annealing are a high-efficiency and sustainable electrocatalytst for OER

Correction: High intrinsic activity of the oxygen evolution reaction in low-cost NiO nanowall electrocatalysts

Correction for 'High intrinsic activity of the oxygen evolution reaction in low-cost NiO nanowall electrocatalysts' by Salvatore Cosentino et al., Mater. Adv., 2020, DOI: 10.1039/d0ma00467g

Urocortin-like immunoreactivity in the primary lymphoid organs of the duck. (Anas platyrhynchos).

Urocortin (UCN) is a 40 aminoacid peptide which belongs to corticotropin-releasing factor (CRF) family. This family of peptides stimulates the secretion of proopiomelanocortin (POMC)-derived peptides, adrenocorticotropic hormone (ACTH), b-endorphin and melanocyte-stimulating hormone (MSH) in the pituitary gland. In the present study, using Western blotting and immunohistochemistry, the distribution of UCN in the primary lymphoid organs of the duck was investigated at different ages. In the cloacal burse and thymus, Western blot demonstrated the presence of a peptide having a molecular weight compatible with that of the mammalian UCN. In the cloacal burse, immunoreactivity was located in the medullary epithelial cells and in the follicular associated and cortico-medullary epithelium. In the thymus, immunoreactivity was located in single epithelial cells. Double labelling immunofluorescence studies showed that UCN immunoreactivity completely colocalised with cytokeratin immunoreactivity in both the thymus and cloacal burse. Statistically significant differences in the percentage of UCN immunoreactivity were observed between different age periods in the cloacal burse. The results suggest that, in birds, urocortin has an important role in regulating the function of the immune system

Role of fluorine in suppressing boron transient enhanced diffusion in preamorphized Si

We have explained the role of fluorine in the reduction of the self-interstitial population in a preamorphized Si layer under thermal treatment. For this purpose, we have employed a B spike layer grown by molecular-beam epitaxy as a marker for the self-interstitial local concentration. The amorphized samples were implanted with 731012, 731013, or 431014 F/cm2 at 100 keV, and afterwards recrystallized by solid phase epitaxy. Thermal anneals at 750 or 850 °C were performed in order to induce the release of self-interstitials from the end-of-range (EOR) defects and thus provoke the transient enhanced diffusion of B atoms. We have shown that the incorporation of F reduces the B enhanced diffusion in a controlled way, up to its complete suppression. It is seen that no direct interaction between B and F occurs, whereas the suppression of B enhanced diffusion is related to the F ability in reducing the excess of silicon self-interstitials emitted by the EOR source. These results are reported and discussed

Comparing different solutions for testing resistive defects in low-power SRAMs

Low-power SRAM architectures are especially sensitive to many types of defects that may occur during manufacturing. Among these, resistive defects can appear. This paper analyzes some types of such defects that may impair the device functionalities in subtle ways, depending on the defect characteristics, and that may not be directly or easily detectable by traditional test methods, such as March algorithms. We analyze different methods to test such defects and discuss them in terms of complexity and test time

Extended point defects in crystalline materials: Ge and Si

B diffusion measurements are used to probe the basic nature of self-interstitial 'point' defects in Ge. We find two distinct self-interstitial forms - a simple one with low entropy and a complex one with entropy ~30 k at the migration saddle point. The latter dominates diffusion at high temperature. We propose that its structure is similar to that of an amorphous pocket - we name it a 'morph'. Computational modelling suggests that morphs exist in both self-interstitial and vacancy-like forms, and are crucial for diffusion and defect dynamics in Ge, Si and probably many other crystalline solids

Carotid Artery Disease in the Era of Biomarkers: A Pilot Study

The intima-media thickness (IMT) and its irregularities or ulcerations in the common carotid artery (CCA) are useful tools as sentinel biomarkers for the integrity of the cardiovascular system. Total homocysteine and lipoprotein levels are the most commonly used elements in cardiovascular risk stratification. Duplex ultrasound (DUS), associated with serum biomarkers, can be used simply to assess the degree of atherosclerotic disease and cardiovascular risk. This study highlights the role of different kinds of biomarkers, showing their usefulness and potentiality in multi-district atherosclerotic patients, especially for early diagnosis and therapy effectiveness monitoring. A retrospective analysis performed from September 2021 to August 2022, of patients with carotid artery disease, was performed. A total of 341 patients with a mean age of 53.8 years were included in the study. The outcomes showed an increased risk of stroke in patients with significative carotid artery disease, nonresponsive to therapy, monitored through a series of serum biomarkers (homocysteine, C-reactive protein, and oxidized LDL). In this reported experience, the systematic use of DUS in association with the multiple biomarkers approach was effective for the early identification of patients at higher risk of disease progression or inefficient therapy

Effect of climate and vegetation on soil organic carbon, humus fractions, allophanes, impolite, kaolinite, and oxyhydroxides in volcanic soils of Etna (Sicily)

A soil sequence along an elevational gradient ranging from subtropical to subalpine climate zones in the Etna region (Sicily, southern Italy) was investigated with respect to organic C, kaolinite, and crystalline to noncrystalline Al and Fe phases. Special emphasis was given to the stabilization of soil organic carbon (SOC) and its interaction with the inorganic phases. The soils were variations of Vitric Andosols that developed on a trachy-basaltic lava flow with an age of 15,000 years. Two main vegetation systems dominated the sites: at the lower sites, it was mainly maquis vegetation and, at the higher elevated sites, predominantly coniferous forest. The concentration of SOC in the topsoil, the SOC stocks in the profiles, the humus fractions such as humic and fulvic acids, functional groups and substances of organic matter, imogolite-type materials (ITM), and oxyhydroxides were found to be strongly related to elevation and, thus, climate (precipitation and temperature) and vegetation. The C/N ratio in the topsoil was especially indicative of the vegetation type. The amount of SOC, ITM, and crystalline Fe oxyhydroxides decreased with increasing altitude. Weathering, as related to the proportion of crystalline Fe-oxyhydroxides or the kaolinite concentration in the clay fraction, seemed to be greater at the lower elevated sites. At these sites, maquis vegetation led to a higher accumulation of SOC as compared with the coniferous trees at the higher sites. Fire activity, as indicated by aromatic compounds in the humic acids and by the presence of charcoal in the soil, has most probably influenced several important soil processes. The identification and radiocarbon dating of charcoal revealed evidence that repeated bush fires had played a significant role in soil formation. The better stabilization of SOC at lower altitudes might be due to the specific climatic conditions with a more pronounced change in periods of humidity alternating with periods of droughts and resultant fire activity. The positive correlation between mean annual temperature and SOC content supports such a hypothesis. The climate- and vegetation-dependent stabilization of organic matter in the soil can be ascribed to the proportion of aromatics in the humic acids, to the presence of noncrystalline Al and Fe phases, to the kaolinite concentration, to the amount of clay, and to a lesser extent to the silt fraction

Expression and potential role of the peptide orexin-A in prostate cancer

The peptides orexin-A and orexin-B and their G protein-coupled OX1 and OX2 receptors are involved in multiple physiological processes in the central nervous system and peripheral organs. Altered expression or signaling dysregulation of orexins and their receptors have been associated with a wide range of human diseases including narcolepsy, obesity, drug addiction, and cancer. Although orexin-A, its precursor molecule prepro-orexin and OX1 receptor have been detected in the human normal and hyperplastic prostate tissues, their expression and function in the prostate cancer (PCa) remains to be addressed. Here, we demonstrate for the first time the immunohistochemical localization of orexin-A in human PCa specimens, and the expression of prepro-orexin and OX1 receptor at both protein and mRNA levels in these tissues. Orexin-A administration to the human androgen-dependent prostate carcinoma cells LNCaP up-regulates OX1 receptor expression resulting in a decrease of cell survival. Noteworthy, nanomolar concentrations of the peptide counteract the testosterone-induced nuclear translocation of the androgen receptor in the cells: the orexin-A action is prevented by the addition of the OX1 receptor antagonist SB-408124 to the test system. These findings indicate that orexin-A/OX1 receptor interaction interferes with the activity of the androgen receptor which regulates PCa onset and progression, thus suggesting that orexin-A and its receptor might represent novel therapeutic targets to challenge this aggressive cancer