Search results for "sulfur"

The Relations between the Sulphur Forms and the Organic and Mineral Components in Soils Developed under Spruce Forests in the Mont Lozere (France)

1992

Mean interannual (1981–1985) hydrochemical input-output budgets indicate net gains of sulphur in forested and unforested watersheds (1150–1450m deviation range) of Mont Lozere (2). The values of the sulphur gains, ranging from 5 to 10 kg/ha/yr. according to the watersheds are underestimated, since dry deposition is not considered in the budgets (1). It is now well known (3,4) that sulphur accumulation in forest catchments is mediated physically by sulphate adsorption on mineral amorphous surfaces and microbially by incorporation of sulphur into soil organic matter. To get a better assessment of these processes, in order to foresee their long term effects upon the proton-budgets and biogeoch…

Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts

2016

The interface between biological and geochemical components in surface crust of a saline soil was investigated using X-Ray Diffraction (XRD), and variable pressure scanning electron microscopy (SEM) in combination with Energy Dispersive X-ray Spectrometry (EDS). Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of su…

Multi-isotopic and trace element evidence against different formation pathways for oyster microstructures

2021

Geochimica et cosmochimica acta 308, 326-352 (2021). doi:10.1016/j.gca.2021.06.012

Bio-polymeric Ionic Liquid Gels for the Desulfurization of Fuel

Microbial acidification and pH effects on trace element release from sewage sludge.

2003

Leaching of sludge-borne trace elements has been observed in experimental and field studies. The role of microbial processes in the mobilization of trace elements from wastewater sludge is poorly defined. Our objectives were to determine trace element mobilization from sludge subjected to treatments representing microbial acidification, direct chemical acidification and no acidification, and to determine the readsorption potential of mobilized elements using calcareous sand. Triplicate columns (10-cm diameter) for incubation and leaching of sludge had a top layer of digested dewatered sludge (either untreated, acidified with H2SO4, or limed with CaCO3; all mixed with glass beads to prevent …

Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies. Part II: Thermodynamic analysis

2014

Abstract A staged equilibrium process model was developed for a bubbling fluidized bed boiler firing SRF, bark and sludge. The model was used to study the influence of sulfur addition strategies (S-pellet additive and peat co-firing) on the behavior of copper, bromine, and alkalis. Aerosol samples collected from the backpass of the boiler were used to validate the chemistry predicted by the model. The model revealed that Cu existed as Cu 2 S (s3) in the reducing zone, and CuCl (g) (for all test cases) and CuO (s) (during peat co-firing) in the oxidation zones. CuBr 3(g) was also present after the introduction of tertiary air. However the model failed to predict the formation of CuSO 4 , an …

Sulfated Lupane Triterpene Derivatives and a Flavone C-Glycoside from Gypsophila repens

2007

A new sulfated lupane triterpene, Gypsophilin (1), and its glucosyl ester, Gypsophilinoside (2) were isolated from the roots of Gypsophila repens whereas a new flavone C-glycoside (3) was obtained from the aerial parts. Their structures were established as (3beta)-3-O-(sulfo)lup-20(29)-en-23,28-dioic acid (1), (3beta)-3-O-(sulfo)lup-20(29)-en-23,28-dioic acid -28-O-beta-D-glucopyranosyl ester (2) and luteolin-7-O-alpha-L-arabinopyranosyl-6-C-beta-glucopyranoside (3) by spectroscopic methods such as 1D and 2D NMR, HR-ESI-MS and FAB-MS.

Garlic and Cancer

2007

Special Issue; International audience; This review summarizes current knowledge on the anticarcinogenic properties of garlic. Collectively epidemiologic studies – mostly casecontrol studies – provide strong evidence that garlic consumption reduces the risk of cancer especially, the risk of gastric and colon cancer. Furthermore many experimental studies demonstrate that organosulfur compounds (OSCs) and garlic extracts can prevent or slow down the carcinogenic process induced by a variety of chemical carcinogens in animals. Garlic and OSCs have been shown to be active during all the stages of carcinogenesis. Several mechanisms have been proposed to explain the cancer-preventive effects of ga…

Cirkonija oksīda nanodaļiņu ietekme uz sulfurētu poliēterēterketona membrānu stiklošanās temperatūru

2019

Cirkonija oksīda nanodaļiņu ietekme uz sulfurēta poli(ēter ēter ketona) membrānu stiklošanās temperatūru. Novikova V., zinātniskais vadītājs, asoc. prof. Dr. ķīm. Vaivars G. Bakalaura darbs, 42 lappuses, 27 attēli, 6 tabulas, 24 literatūras avoti. Latviešu valodā. Darbā tika veikta poliēterēterketona sulfonēšana, izgatavotas sulfurētu poliēterēter ketonu membrānas ar vienu sulfonēšanas pakāpi, kuru noteica ar titrimetrijas metodi, izgatavotas sulfurēta poliēterēterketonu ar dažādu cirkonija dioksīda saturu kompozītu membrānas un noteiktas šo membrānu stiklošanās temperatūras ar diferenciālu skenējošo kalorimetru DSC131 EVO, kā arī noteikti vislabākie apstākļi, kuros veic mērīšanu.

Silver Clusters of Five Atoms as Highly Selective Antitumoral Agents Through Irreversible Oxidation of Thiols

2022

Low atomicity clusters present properties dependent on the size, due to the quantum confinement, with well-defined electronic structures and high stability. Here it is shown that Ag5 clusters catalyze the complete oxidation of sulfur to S+6. Ag5 catalytic activity increases with different oxidant species in the order O2 ≪ H2O2 < OH•. Selective oxidation of thiols on the cysteine residues of glutathione and thioredoxin is the primary mechanism human cells have to maintain redox homeostasis. Contingent upon oxidant concentration, Ag5 catalyzes the irreversible oxidation of glutathione and thioredoxin, triggering apoptosis. Modification of the intracellular environment to a more oxidized state…