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    EPR spectra and lithogeochemistry of jasperoids at Carlin, Nevada: distinction between auriferous and barren rocks
    (Elsevier, 1995-12) van Moort, JC; Hotchkis, MAC; Pwa, A
    The acid insoluble residue of twenty-nine gold-bearing and ten barren jasperoids from Carlin, Nevada, were analysed by electron paramagnetic resonance powder spectroscopy (EPR), and by simultaneous proton-induced X-ray emission (PIXE) and proton-induced gamma ray emission (PIGME) spectroscopy. The mineralised samples are characterised by high Li, F, AI, K, Ti, Rb, V, Y, and Zr values in general and by significantly higher Rb/Al and V/Al ratios in particular. The chemical differences are largely caused by the abundance and type of sericite present. Significant differences in EPR intensity exist between the mineralised and barren jasperoids. © 1995 Published by Elsevier B.V.
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    Hydrogen depth profiles and microhardness of electrochemically hydrogen-charged nanostructured bainitic steels
    (Elsevier, 2019-05-21) Kazum, O; Ionescu, M; Beladi, H; Kannan, MB
    Hydrogen depth profiles and microhardness of the electrochemically hydrogen-charged nanostructured bainitic steels (produced at two different transformation temperatures, i.e. 200 °C (NBS200)and 350 °C (NBS350))were obtained using elastic recoil detection analysis (ERDA)technique and Vickers microhardness testing, respectively, and compared to that of mild steel. The ERDA results showed that the subsurface hydrogen concentration was higher in NBS200, followed by NBS350 and mild steel. However, the microhardness data of the hydrogen-charged steels revealed material softening in NBS200 and NBS350, whereas the mild steel exhibited material hardening effect. The microhardness along the cross-sectional depth of the steels showed that the softening effect in NBS200 was closer to the hydrogen-charged surface compared to that of NBS350. The plausible mechanisms for the softening effect in the NBS200 and NBS350, and hardening effect in mild steel have been discussed in this paper. © 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd.
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    Cadmium bioaccumulation dynamics during amphibian development and metamorphosis
    (Elsevier, 2024-08) Lanctôt, C; Callaghan, PD; Cresswell, T
    Cadmium pollution poses a significant threat to aquatic ecosystems due to its propensity to bioaccumulate and cause toxicity. This study assessed the complex dynamics of cadmium uptake, accumulation and distribution across anuran development to provide new insights into the fate of cadmium burdens during metamorphosis and compare the susceptibility of different life stages to cadmium accumulation. Tadpoles of various developmental stages were exposed to dissolved 109-cadmium and depurated in clean water in a series of experiments. Temporal changes in whole-body and tissue concentrations were analysed using gamma spectroscopy, and anatomical distributions were visualised using autoradiography. Results showed that animals exposed at the onset of metamorphic climax (forelimb emergence) retained significantly less cadmium than animals exposed through larval stages. After exposure, cadmium partitioned predominantly in the skin, gills and remains of metamorphs, whereas larvae accumulated cadmium predominately through their gut. This shows a shift in the primary route of uptake at the onset of climax, which relates to the structural and functional changes of uptake sites through metamorphosis. During climax, some cadmium was redistributed in tissues developing de novo, such as the forelimbs, and concentrated in the regressing tail. Our findings highlight the need for stage-specific considerations in assessing exposure risks. © 2024 The Author(s). Published by Elsevier B.V. Open Access CC-BY 4.0
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    Evaluation of interfacial toughness and bond strength of sandwiched silicon structures
    (Elsevier, 2002-05-31) Latella, BA; Nicholls, TW; Cassidy, DJ; Barbé, CJ; Triani, G
    Results of a study to measure the interfacial strength and toughness in sandwiched silicon structures, using sol-gel processing as the bonding method, are examined. The interfacial bond strength was determined using a standard uniaxial tensile test, while a relative measure of interface toughness was ascertained using exploratory Vickers indentations. The specimens were positioned and aligned so that the indentations were made directly on the interface region, with the cracks emanating from one set of the impression diagonals at the free surface coinciding with the trace of the interface. The length of these radial cracks, having a penny-like configuration, required to cause debonding at the interface was measured in order to provide relative fracture toughness and fracture energy values. Indications of 'local' bond toughness were obtained by indenting at locations near the interface and following the path of the radial cracks. The applicability of the technique with reference to material interfaces is discussed. © 2002 Elsevier Science B.V.
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    The water chemistry and microbiome of household wells in Medawachchiya, Sri Lanka, an area with high prevalence of chronic kidney disease of unknown origin (CKDu)
    (Springer Nature, 2020-10-26) McDonough, LK; Meredith, KT; Nikagolla, C; Middleton, RJ; Tan, JK; Ranasinghe, AV; Sierro, F; Banati, RB
    Chronic kidney disease (CKD) of unknown etiology (CKDu) mostly affects agricultural communities in Central America, South Asia, Africa, but likely also in North America and Australia. One such area with increased CKDu prevalence is the Medawachchiya District Secretariat Division of the Anuradhapura District in the North Central Province of Sri Lanka. Recent research has focused on the presence of various microbial pathogens in drinking water as potential causal or contributing factors to CKDu, yet no study to date has performed a more comprehensive microbial and water chemistry assessment of household wells used for domestic water supply in areas of high CKDu prevalence. In this study, we describe the chemical composition and total microbial content in 30 domestic household wells in the Medawachchiya District Secretariat Division. While the chemical composition in the tested wells mostly lies within standard drinking water limits, except for high levels of fluoride (F), magnesium (Mg), sodium (Na), chloride (Cl) and calcium (Ca) in some samples, we find a frequent presence of cyanotoxin-producing Microcystis, confirming earlier studies in Sri Lanka. Since the total microbial content of drinking water also directly influences the composition of the human gut microbiome, it can be considered an important determinant of health. Several bacterial phyla were previously reported in the gut microbiome of patients with CKD. Using these bacteria phyla to define operational taxonomic units, we found that these bacteria also occur in the microbiome of the sampled well water. Based on available environmental data, our study demonstrates associations between the abundances of these bacteria with geographical distribution, well water temperature and likely fertilizer use in the local surface water catchment area of the individual household wells. Our results reinforce the recommendation that household wells with stagnant or infrequently used water should be purged prior to use for drinking water, bathing and irrigation. The latter is suggested because of the reported potential accumulation of bacterial toxins by agricultural crops. The observation that bacteria previously found in chronic kidney disease patients are also present in household wells requires a more detailed systematic study of both the human gut and drinking water microbiomes in CKDu patients, in relation to disease prevalence and progression. © Crown 2022. Open Access CC-BY licence