Search results for "Amination"
showing 10 items of 1702 documents
Effects of earthworms on decomposition and metal availability in contaminated soil: Microcosm studies of populations with different exposure histories
2006
Abstract Population-specific differences in the responses of earthworms to simultaneous exposure to Cu and Zn were studied in microcosm experiments. Two populations of Aporrectodea caliginosa tuberculata (Eisen) with different metal exposure histories were chosen for the studies. Microcosms were prepared containing either uncontaminated soil or soils with low or high combined Cu/Zn -concentrations (79/139 or 178/311 mg kg −1 dry mass of soil, respectively). Earthworms from each population were introduced to the microcosm treatments with some microcosms serving as controls without earthworms. One series of microcosms was destructively sampled after 16 weeks incubation in a climate chamber. S…
Presence of mycotoxins in Tunisian infant foods samples and subsequent risk assessment
2018
Abstract A study on a set of cereal and cereal-based products (n = 117) intended for infant consumption was performed to determine the natural presence of twenty different mycotoxins by both liquid chromatography and gas chromatography coupled to tandem mass spectrometry (MS/MS). Analytical data showed that 67% of analyzed samples were contaminated by at least one mycotoxin at variable levels. Deoxynivalenol presented the highest incidence (38%) and reached a maximum level of 240 ng/g in a bsissa sample (oat product), higher than the maximum level set for DON in cereal products (200 ng/g). While, enniatin B was found in 25 samples with a maximum level of 316 ng/g found also in a bsissa samp…
Machine learning analysis of e-nose signal in early detection of mold contamination in buildings
2017
Grzyb rozwijający się na ścianach budynków jest głównym powodem zjawiska, które nazwano Syndromem Chorego Budynku. Wolne związki organiczne emitowane przez grzyby mogą być wykryte różnymi metodami, m.in. na podstawie chromatografii, ale także za pomocą matryc czujników gazowych. Wszystkie tego typu narzędzia generują sygnały elektryczne, które można analizować za pomocą odpowiednich technik statystycznych. Praca skupia się na zastosowaniu nadzorowanych i nienadzorowanych technik uczenia maszynowego w ocenie sygnału pochodzącego z elektronicznego nosa.
Stereoselective Synthesis and Pharmacological Evaluation of 2,4-Bridged Piperidine Derivatives Designed to Activate the κ-Opioid Receptor
2021
L‐Aspartate as a high‐quality nitrogen source in Escherichia coli : Regulation of L‐aspartase by the nitrogen regulatory system and interaction of L‐…
2020
Escherichia coli uses the C4-dicarboxylate transporter DcuA for L-aspartate/fumarate antiport, which results in the exploitation of L-aspartate for fumarate respiration under anaerobic conditions and for nitrogen assimilation under aerobic and anaerobic conditions. L-Aspartate represents a high-quality nitrogen source for assimilation. Nitrogen assimilation from L-aspartate required DcuA, and aspartase AspA to release ammonia. Ammonia is able to provide by established pathways the complete set of intracellular precursors (ammonia, L-aspartate, L-glutamate, and L-glutamine) for synthesizing amino acids, nucleotides, and amino sugars. AspA was regulated by a central regulator of nitrogen meta…
Evaluation of Mycotoxin Residues on Ready-to-Eat Food by Chromatographic Methods Coupled to Mass Spectrometry in Tandem
2018
Simultaneous determination of twenty-seven mycotoxins in ready-to-eat food samples using &ldquo
Sterigmatocystin: Occurrence, toxicity and molecular mechanisms of action – A review
2020
The mycotoxin sterigmatocystin (STE) is produced mainly by Aspergillus fungi. It has been reported to occur in grains and grain-based products, cheese, coffee, spices and beer. The STE is a known biogenic precursor of aflatoxin B1, sharing with it several structural and biological similarities. The STE has been shown to be hepatotoxic and nephrotoxic in animals and it has been classified as possible human carcinogen (group 2B) by IARC. The STE has been reported to cause a marked decrease in cell proliferation in different mammalian cells. Data available on literature suggest that the cellular mechanisms underlying STE-induced toxicity include the induction of oxidative stress, mitochondrial…
Method optimization to measure polybrominated diphenyl ether (PBDE) concentrations in soils of Bratislava, Slovakia.
2010
We modified an analytical method to determine polybrominated diphenyl ethers (PBDEs) in urban soils of Bratislava (Slovakia). Gel permeation chromatography (GPC) introduced as a clean-up step for soil extracts substantially reduced matrix enhancements when PBDEs were measured with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The resulting method proved to be accurate, precise, and showed low detection limits. The sum of 15 PBDE concentrations in surface horizons of Bratislava soils ranged from 87 to 627 pg g(-1). PBDE concentrations were mostly higher in surface than deeper horizons probably because of atmospheric deposition and lack of substantial vertical…
Rośliny naczyniowe jako bioindykatory stanu środowiska
2017
Dzięki coraz nowocześniejszym i powszechniej stosowanym metodom bioindykacji można dokonać precyzyjnej i stosunkowo wydajnej oceny stanu środowiska naturalnego oraz zmian w nim zachodzących.Wymiernym sposobem monitoringu przyrody są obserwacje reakcji żywych organizmów. Badania przeprowadza się głównie z użyciem stenobiontów, czyli taksonów o małej tolerancji na zmienność warunków środowiska. Grupę roślin oraz zwierząt wykorzystywanych w badaniach bioindykacyjnych nazywa się wskaźnikowymi.Bioindykacja znajduje zastosowanie w geologii poszukiwawczej do odnajdywania miejsc z możliwością pozyskania cennych kruszców oraz w ochronie środowiska do monitoringu stanu jego zanieczyszczenia. Na podst…
Influence of Environmental Pollution and Living Conditions on Parasite Transmission among Indigenous Ecuadorians
2022
The purpose of this study was to evaluate the influence of environmental pollution and the living conditions of indigenous Ecuadorians on the transmission of enteroparasites in an Andean agricultural area located at high altitude. Environmental pollution was recorded after observation in each community. The parasites were identified by microscopic sediment analysis using physiological saline solution from macerated arthropods, washed vegetables, and human stools, utilizing four coproparasitological techniques (direct examination, Kato–Katz, ether concentration, and Ziehl–Neelsen). The results show that the inadequate disposal of human and animal excreta that contaminate soil and…