Browsing by Subject "Metals"

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  • Kahkonen, Mika A.; Miettinen, Otto; Hilden, Kristiina S. (2020)
    The impacts of Ho and Li (0, 10, 50, 200 mg/L) were tested towards the growth of four basidiomycetous fungal species, their ability to decolorise synthetic dyes (Reactive Green 19, Reactive Orange 16, Reactive Black 5), and produce oxidative enzymes. All species;Agrocybe dura,Skeletocutis biguttulata,Exidia saccharinaandGalerina paludosa;grew with and without supplemented Ho or Li. The growth ofS. biguttulatawas the most tolerant species towards Ho or Li (200 mg/L), whereas the growth ofG. paludosawas the most sensitive of the studied species to both 200 mg Ho or Li/L. All fungi oxidized ABTS [2,2 '-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] forming colour zone on plate tests indicating production of lignin modifying laccase enzyme.A. duraandG. paludosa,formed black MnO(2)zone in Mn(2+)plates, which indicates the production of manganese peroxidase (MnP).A. duraandG. paludosadecolorised Reactive Black 5 indicating the production of versatile peroxide (VP) enzyme. Our study presents two new candidate species able to produce VP.A. durawas capable of decolorising all tested synthetic dyes in the presence of Ho or Li (0-200 mg/L) suggesting that this fungus is a promising species for bioremediation of multi dye-containing wastes.
  • Talvio, Karo; Kanninen, Katja; White, Anthony; Koistinaho, Jari; Castrén, Maija (Helsingin yliopisto, 2021)
    Biometalleilla on merkittävä rooli solujen ja kudosten toiminnassa. Ne ovat monen entsyymin toiminnassa elintärkeitä, mutta toisaalta solut pyrkivät pitämään niiden pitoisuudet tarkoissa rajoissa. Metallin yli- tai alimäärä voi joko itsessään vaikeuttaa solujen normaalia toimintaa tai olla merkki epätavallisesta metaboliasta. Fragile X-oireyhtymä on monogeeninen kehitysvammaisuutta aiheuttava perinnällinen sairaus, joka johtuu FMRP-proteiinin puutoksesta. Oireyhtymä on mahdollisesti yleisin periytyvän autismin syy. 23 metallin kudospitoisuudet mitattiin Fragile X-oireyhtymää mallintavan hiirimallin ja kontrollihiirten pikkuaivoista, isoaivokuorelta, maksasta, sydämestä ja pernasta induktiivisesti kytketty plasma -massaspektrometrillä. Seitsemän metallin – Cu, Fe, K, Mg, Mn, Na ja P – pitoisuudet olivat mittausrajan yläpuolella. Hiirimallin sydämen ja pikkuaivojen rautapitoisuudet olivat korkeampia kuin kontrollihiirten vastaavista kudoksista mitatut arvot. Löydösten merkitsevyydet olivat kuitenkin statistisesti raja-arvoisia. PCA-analyysi vahvisti käsitystä muuttuneesta metallihomeostaasista hiirimallin sydämessä, ja toisaalta Fragile X-oireyhtymän aiheuttavan FMRP-proteiinin mutaatiot on aiemmin liitetty ihmisillä pikkuaivojen rautakertymiin. Tutkimus kärsii pienen näytemäärän takia alhaisesta voimasta, mutta rautamuutokset sopivat aiemmin kuvattuun FMRP-proteiiniin liitettyyn inflammaatioon. Tässä tutkimuksessa sekä aiemmissa julkaisuissa kuvattu biometallien epätasapaino edellyttää lisätutkimusta aiheesta, sillä metalleja sisältäviä lisäravinteita kokeillaan usein hoidoksi hermoston kehityshäiriöissä.
  • Talvio, Karo; Kanninen, Katja M.; White, Anthony R.; Koistinaho, Jari; Castren, Maija L. (2021)
  • Chattopadhyay, Arnab; Huertas Suarez, Andres Felippe; Rebeiro-Hargrave, Andrew; Fung, Pak Lun; Varjonen, Samu; Hieta, Tuomas; Tarkoma, Sasu; Petäjä, Tuukka (2022)
    Formaldehyde is a carcinogenic indoor air pollutant emitted from common wood-based materials. Low-cost sensing of formaldehyde is difficult due to inaccuracies in measuring low concentrations and susceptibility of sensors to changing indoor environmental conditions. Currently gas sensors are calibrated by manufacturers using simplistic models which fail to capture their complex behaviour. We evaluated different low-cost gas sensors to ascertain a suitable component to create a mobile sensing node and built a calibration algorithm to correct it. We compared the performance of 2 electrochemical sensors and 3 metal oxide sensors in a controlled chamber against a photo-acoustic reference device. In the chamber the formaldehyde concentrations, temperature and humidity were varied to assess the sensors in diverse environments. Pre-calibration, the electrochemical sensors (mean absolute error (MAE) = 70.8 ppb) outperformed the best performing metal oxide sensor (MAE = 335 ppb). A two-stage calibration model was built, using linear regression followed by random forest, where the residual of the first stage acted as a input for the second. Post-calibration, the metal oxide sensors (MAE = 154 ppb) improved compared to their electrochemical counterparts (MAE = 78.8 ppb). Nevertheless, the uncalibrated electrochemical sensor showed overall superior performance hence was selected for the mobile sensing node.
  • Ruiz, Sandra R.; Eeva, Tapio; Kanerva, Mirella; Blomberg, Anna; Lilley, Thomas M. (2019)
    Metal elements, ubiquitous in the environment, can cause negative effects in long-lived organisms even after low but prolonged exposure. Insectivorous bats living near metal emission sources can be vulnerable to such contaminants. Although it is known that bats can bioaccumulate metals, little information exists on the effects of metal elements on their physiological status. For example, oxidative status markers are known to vary after detoxification processes and immune reactions. Here, for two consecutive summers, we sampled individuals from a natural population of the insectivorous bat, Myotis daubentonii, inhabiting a site close to a metal emission source. We quantified metals and metalloids (As, Ca, Cd, Co, Cu, Mn, Ni, Pb, Se, Zn) from individual fecal pellets. We measured enzymatic antioxidants (GP, CAT, SOD), total glutathione (tGSH) and ratio between reduced and oxidized glutathione (GSH:GSSG) from their red blood cells together with biometrics, hematocrit and parasite prevalence. In general, metal concentrations in feces of M. daubentonii reflected the exposure to ambient contamination. This was especially evident in the higher concentrations of Cd, Co, Cu and Ni close to a smelter compared to a site with less contaminant exposure. Annual differences were also observed for most elements quantified. Sex-specific differences were observed for calcium and zinc excretion. SOD and CAT enzymatic activities were associated with metal levels (principal components of six metal elements), suggesting early signs of chronic stress in bats. The study also shows promise for the use of non-invasive sampling to assess the metal exposure on an individual basis and metal contamination in the environment.
  • Venäläinen, Salla H.; Hartikainen, Helinä (2018)
    Treatment of acidic mining water (MW) with industrial minerals and alkaline chemicals requires utilisation of unrenewable raw materials and produces disposable inorganic sludges of no further use. We investigated the efficiency of bio-based anionic nanofibrillated cellulose (NFC) to purify authentic MW high in metals and sulphate. In a short-term (10 min) adsorption experiment, highly acidic (pH 3.2) multi-metal process water was treated with anionic NFC gels differing in their consistency (1.1%, 1.4% and 1.8% wow) at three sorbent-to-solution ratios. To unravel the purification efficiency of the NFC gels, MW was treated stepwise with a set of fresh NFC gels in three sequential batches. Each treated solution was filtrated before pH measurement and analysis for the NFC-induced changes in the metal and sulphate concentrations. All NFC gels efficiently co-adsorbed metals and sulphate and decreased the acidity of MW. Depending on the dosage, a triplicated treatment with the NFC gels removed as much as 32-75% of metal cations and 34-75% of sulphate anions. The retention of metals highly exceeded the amount of carboxyl groups in the sorbent Thus, we concluded that, instead of electrostatic adsorption, the retention took place through formation of covalent metal-NFC complexes. The subsequent surplus in positive total charge formed on the NFC-surface, in turn, enabled electrostatic co-adsorption of sulphate anions. The mutual interactions between cellulose nanofibrils in the NFC gel weakened with decreasing consistency, which promoted the accessibility of the sorption sites. This improved the purification efficiency while decreasing the demand for cellulosic raw material. We concluded that anionic NFC could potentially serve as a multifunctional and resource-efficient purification agent in the treatment of acidic process waters of high ionic strength. Ideally, the elements retained could be liberated and recycled elsewhere. (C) 2018 Elsevier Ltd. All rights reserved.