Biometal Dyshomeostasis in Olfactory Mucosa of Alzheimer's Disease Patients

Olfactory function, orchestrated by the cells of the olfactory mucosa at the rooftop of the nasal cavity, is disturbed early in the pathogenesis of Alzheimer's disease (AD). Biometals including zinc and calcium are known to be important for sense of smell and to be altered in the brains of AD patients. Little is known about elemental homeostasis in the AD patient olfactory mucosa. Here we aimed to assess whether the disease-related alterations to biometal homeostasis observed in the brain are also reflected in the olfactory mucosa. We applied RNA sequencing to discover gene expression changes related to metals in olfactory mucosal cells of cognitively healthy controls, individuals with mild cognitive impairment and AD patients, and performed analysis of the elemental content to determine metal levels. Results demonstrate that the levels of zinc, calcium and sodium are increased in the AD olfactory mucosa concomitantly with alterations to 17 genes related to metal-ion binding or metal-related function of the protein product. A significant elevation in alpha-2-macroglobulin, a known metal-binding biomarker correlated with brain disease burden, was observed on the gene and protein levels in the olfactory mucosa cells of AD patients. These data demonstrate that the olfactory mucosa cells derived from AD patients recapitulate certain impairments of biometal homeostasis observed in the brains of patients.Peer reviewe

Effect of waste rock dilution on spodumene flotation

Abstract The effect of waste rock minerals introduced by dilution on the flotation of spodumene was investigated. The objectives of this work were to investigate how flotation yield and grades deteriorate mainly by Mg-bearing biotite and amphiboles that are introduced to the system by waste rock dilution and find the possible ways to improve the flotation performance regarding these Mg-bearing minerals. Laboratory flotation tests were conducted with modifications to the standard procedure and new conditions. Analytical methods used in this work include mineralogical tests like electron probe micro-analyzer (EPMA) to find out accurate elemental assays for the minerals in the deposit, especially biotite. X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS) to analyse flotation products contents. Mineral liberation analysis (MLA) for liberation, associations, Mg-distribution and modal mineralogy. Information about mineral recoveries in different flotation stages was obtained from element to mineral conversion calculations with HSC Chemistry software. The target grade and recovery of Li₂O for the Rapasaari ore were established on 4.5% and 84.18% (as a previous standard test). The use of Na₂CO₃ and starch modifiers gave promising results slightly improving the recoveries to 85.29% and 85.11% respectively while reaching almost 4.5% grade in final concentrate. Mineral liberation analysis (MLA) showed that biotite contains most of the Mg (80–90%), other minerals are amphiboles (mainly edenite and hornblende) and in less extent chlorite and clays. Biotite and amphiboles end up in the final concentrate mostly fully liberated while apatite is mostly coarse mixed grains. Mg-bearing minerals float into the concentrate because of similar surface properties with spodumene. Those similar properties may be due to chemically active Al-O sites that form on the mineral surfaces when the mineral breaks through its cleavage planes during comminution. Al-O sites act as collector attachment spots in fatty acid flotation and compete for collector adsorption