Search results for " Photochemical"

showing 10 items of 13 documents

Screening of physical–chemical methods for removal of organic material, nitrogen and toxicity from low strength landfill leachates

2002

Physical-chemical methods have been suggested for the treatment of low strength municipal landfill leachates. Therefore, applicability of nanofiltration and air stripping were screened in laboratory-scale for the removal of organic matter, ammonia, and toxicity from low strength leachates (NH4-N 74-220 mg/l, chemical oxygen demand (COD) 190-920 mg O2/l, EC50 = 2-17% for Raphidocelis subcapitata). Ozonation was studied as well, but with the emphasis on enhancing biodegradability of leachates. Nanofiltration (25 degrees C) removed 52-66% of COD and 27-50% of ammonia, the latter indicating that ammonia may in part have been present as ammonium salt complexes. Biological pretreatment enhanced t…

Environmental EngineeringChemical PhenomenaNitrogenHealth Toxicology and MutagenesisDaphnia magnaWater Purificationchemistry.chemical_compoundAmmoniaOxidants PhotochemicalOzoneRaphidocelis subcapitataAmmoniaToxicity TestsAnimalsSoil PollutantsEnvironmental ChemistryWater PollutantsAmmoniumAir strippingLeachateOrganic ChemicalsbiologyChemistry PhysicalChemical oxygen demandPublic Health Environmental and Occupational HealthGeneral MedicineGeneral Chemistrybiology.organism_classificationPollutionAcute toxicityRefuse DisposalOxygenDaphniachemistryEnvironmental chemistryFiltrationChemosphere
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Continuous monitoring of photocatalytic treatment by flow injection. Degradation of dicamba in aqueous TiO2 dispersions

2001

The possible use of flow injection (FI) to monitor the photocatalytic mineralization of dicamba (3,6-dichloro-2-methoxybenzoic acid) present at the trace level in aqueous solutions containing TiO2 suspensions has been evaluated. Experiments were performed in a stirred photochemical reactor equipped with a simple FI manifold, integrating an online filtration unit able to perform the monitoring of the UV absorbance of the irradiated solution every 4 min. The light source used was a medium pressure mercury lamp (125 W). During the initial steps of the reaction the formation of UV absorbing intermediates, which completely disappear in less than 80 min, was evidenced. Additional HPLC, DOC and ch…

Environmental EngineeringPhotochemistryUltraviolet RaysHealth Toxicology and MutagenesisChlorideMineralization (biology)Catalysislaw.inventionOxidants PhotochemicallawmedicineEnvironmental ChemistryIrradiationFiltrationTitaniumAqueous solutionChromatographyHerbicidesChemistryWater PollutionDicambaPublic Health Environmental and Occupational HealthGeneral MedicineGeneral ChemistryPollutionPhotocatalysisDegradation (geology)Water treatmentWater Pollutants Chemicalmedicine.drug
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Interactions between willows and insect herbivores under enhanced ultraviolet-B radiation

2002

We studied the effects of elevated ultraviolet-B radiation on interactions between insect herbivores and their host plants by exposing two species of phytochemically different willows, Salix myrsinifolia and S. phylicifolia, to a modulated increase in ultraviolet radiation in an outdoor experiment and monitoring the colonisation of insect herbivores on these willows. We examined the effect of increased ultraviolet-B (UV-B) radiation on (1) the quality of willow leaves, (2) the distribution and abundance of insect herbivores feeding on these willows, (3) the resulting amount of damage, and (4) the performance of insect larvae feeding on the exposed plant tissue. Six clones of each of the two…

HerbivoreWillowSalix phylicifoliaPhratora vitellinaebiologyUltraviolet RaysPopulation DynamicsfungiSalixEnvironmentbiology.organism_classificationAdaptation PhysiologicalColeopteraColonisationOxidants PhotochemicalOzoneSalix myrsinifoliaSalicaceaeLarvaBotanyAnimalsPlants EdibleEcology Evolution Behavior and SystematicsLeaf beetleOecologia
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Photoinduced chemiluminescence of pharmaceuticals

2005

Abstract A screening test for the forward development of chemiluminescence systems able to determine pharmaceutical compounds is reported. The test is based on the on-line photodegradation of the drugs by using a photoreactor consisting of 697 cm × 0.5 mm PTFE tubing helically coiled around an 8 W low-pressure mercury lamp. Photodegraded pharmaceuticals are detected by direct chemiluminescence of the resulting photofragments and their subsequent reaction with potassium permanganate in sulphuric acid medium as oxidant. The screening comprised 97 compounds with different molecular structures and relevant members of the most important families of pharmaceuticals are tested (amino acids, carbox…

LuminescenceLightScreening testPhotochemistryClinical BiochemistryPharmaceutical Sciencebeta-LactamsAnalytical Chemistrylaw.inventionStructure-Activity Relationshipchemistry.chemical_compoundAlkaloidsOxidants PhotochemicalPotassium PermanganatePhenothiazineslawDrug DiscoverymedicineOrganic chemistryEphedrinePhotodegradationSpectroscopyChemiluminescencechemistry.chemical_classificationBicyclic moleculePhotodissociationHydrogen-Ion ConcentrationAmino acidPotassium permanganatePharmaceutical Preparationschemistrymedicine.drugJournal of Pharmaceutical and Biomedical Analysis
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Genotoxic potential of by-products in drinking water in relation to water disinfection: Survey of pre-ozonated and post-chlorinated drinking water by…

2006

Mutagenic potential of drinking water samples derived from ranneywells was studied. 100-100 l of untreated (rough) and ozone-treated as well as chlorinated-disinfected water were dropped on and adsorbed by macroreticular resin columns (Serdolit PAD-III and Amberlite XAD-2). The adsorbed material was desorbed by methanol and dichloromethane. After elimination of the solvents by vacuum distillation the adsorbed material was dissolved in dimethylsulfoxide. The mutagenic activity was tested in the Ames-Salmonella/rat liver microsome system. The tester strains were TA-98 and TA-100. The material adsorbed to Serdolit PAD-III from rough and also disinfected water did not induce mutagenicity in cas…

MaleSalmonella typhimuriumAmberliteIn Vitro TechniquesToxicologymedicine.disease_causeAmes testchemistry.chemical_compoundOxidants PhotochemicalOzoneAdsorptionWater SupplyBy-productmedicineAnimalsDimethyl SulfoxideHistidineDichloromethaneChromatographyMutagenicity TestsSterilizationSterilization (microbiology)RatschemistryEnvironmental chemistryMicrosomes LiverMethanolChlorineGenotoxicityChromatography LiquidDisinfectantsMutagensToxicology
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Photochemical synthesis of pyrene perfluoroalkyl derivatives and their embedding in a polymethylmethacrylate matrix: a spectroscopic and structural s…

2014

A photochemical, alternative and eco-compatible approach to perfluoroalkyl derivatives of pyrene is presented. The perfluoroalkyl chain is regiospecifically introduced at the 1 position of pyrene. The synthesized products have been embedded in a polymethylmethacrylate matrix by photocuring at 365 nm. Both the photochemical reactions can be considered a “green tool” for the synthetic chemist in order to obtain materials with prospective optoelectronic applications. The so-obtained composites have been the object of a study by UV and fluorescence spectroscopy in order to explore their luminescence properties. The small angle X-ray scattering and the transmission electron microscopy techniques…

Materials scienceScatteringGeneral ChemistryMicrostructurePhotochemistryFluorescence spectroscopyPyrene PMMA Photochemical perfluoroalkylation OLEDMatrix (chemical analysis)chemistry.chemical_compoundchemistryTransmission electron microscopyMaterials ChemistryOLEDPyreneLuminescence
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Macroalgal responses to ocean acidification depend on nutrient and light levels

2015

Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ …

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityChlorophyll aFucoxanthininorganicAlkalinityPhotosynthetic efficiency standard errorChlorophyll cNitrogen content per dry mass standard errorLight saturation point standard errorPhenolics allTemperature waterCarbon inorganic dissolvedMacroalgaeCalculated using seacarb after Nisumaa et al 2010Carbon Nitrogen ratioAragonite saturation stateAlkalinity totalallCarbon per dry massSalinity standard errortotalCarbon content per dry mass standard errorPhenolics all standard errorCO2 ventChromistapHMaximum photochemical quantum yield of photosystem II standard errorTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errordissolvedAntioxidant activity standard errorCarbonate ionMaximum photochemical quantum yield of photosystem IIPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Field experimentstandard errorNitrogen content per dry massElectron transport rate standard errorFucoxanthin standard errorEarth System ResearchViolaxanthinPhenolicsChlorophyll a standard errorCarbon dioxide standard errorPotentiometric titrationCalcite saturation stateCarbon/Nitrogen ratio standard errorNitrogenOchrophytaPotentiometricper dry masswaterChlorophyll c standard errorBenthosAlkalinity total standard errorAntioxidant activityElectron transport rateLight saturation pointOcean Acidification International Coordination Centre OA ICCMacro-nutrientsMediterranean SeaNitrogen per dry massBicarbonate ionTemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciespH standard errorCalcite saturation state standard errorCystoseira compressaCalculated using CO2SYSNon photochemical quenchingCarbon content per dry massCarbonate system computation flagViolaxanthin standard errorPrimary production/PhotosynthesisFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonCarbon/Nitrogen ratioBiomass/Abundance/Elemental compositionTreatmentPartial pressure of carbon dioxide water at sea surface temperature wet airAragonite saturation state standard errorCarbon dioxideMacro nutrientsCarbonate ion standard errorSingle speciesFugacity of carbon dioxide water at sea surface temperature wet airPadina pavonicaBiomass Abundance Elemental compositionCoast and continental shelfPhotosynthetic efficiencyBicarbonate ion standard errorNon photochemical quenching standard error
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Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent

2014

We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and delta 13C of leaves and epiphytes were significantly lower at the low pH station. Photosynthetic activity of C. nodosa was stimulated by low pH as seen by the significant increase in…

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityChlorophyll ainorganicAlkalinityLight saturation point standard errorPhotosynthetic quantum efficiencyMediterranean Sea Acidification in a Changing Climate MedSeATemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010IrradianceRespiration rate carbonAragonite saturation stateBiomassAlkalinity totalIrradiance standard errortotalCO2 ventCymodocea nodosapHRespirationEpiphytes loadMaximum photochemical quantum yield of photosystem II standard errorNet community production of carbonTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errordissolvedRespiration rate carbon standard errorCarbonate ionMaximum photochemical quantum yield of photosystem IIPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Net community production of carbon standard errorIlluminance standard errorSoft bottom communitystandard errorCarbon inorganic dissolved standard errorRespiration rateElectron transport rate standard errorEarth System Researchδ13CPhotosynthetic quantum efficiency standard errorField observationChlorophyll a standard errorGross primary production of carbonBiomass standard errorCalcium carbonatePotentiometric titrationCalcite saturation stateShoot densityPotentiometricwaterIlluminanceOxygen standard errorBenthosAlkalinity total standard errorMediterranean Sea Acidification in a Changing Climate (MedSeA)Electron transport rateLight saturation pointOcean Acidification International Coordination Centre OA ICCMediterranean SeaGross primary production of carbon standard errorBicarbonate ionSoft-bottom communityδ13C standard errorTemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciespH standard errorCarbonate system computation flagloadPrimary production/PhotosynthesisFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonBiomass/Abundance/Elemental compositionTreatmentEpiphytes load standard errorOxygenPartial pressure of carbon dioxide water at sea surface temperature wet airEpiphytes loadCarbon dioxideCarbon standard errorEntire communityFugacity of carbon dioxide water at sea surface temperature wet airGroupBiomass Abundance Elemental compositionCoast and continental shelfEpiphytesShoot density standard errorCalcium carbonate standard error
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DNA Oxidation Photoinduced by Norharmane Rhenium(I) Polypyridyl Complexes: Effect of the Bidentate N,N′-Ligands on the Damage Profile

2018

Re(I)--polypyridyl complexes have interesting and distinctive photochemical and photosensitizing properties. This work describes the capability to induce (or photoinduce) DNA damage of three Re(I)-complexes with a naturally occurring alkaloid called norharmane (nHo) as ligand: [Re(CO)₃ (nHo)(L)]CF₃ SO₃ where L=2,2'-bipyridine (ReBpy), phenanthroline (RePhen) or dipyrido[3,2-a:2',3'-c]phenazine (ReDppz). The interaction of the complexes with DNA was investigated by steady-state and time-resolved spectroscopy. Data show that the mode and strength of interaction depend on the chemical structure of the bidentate ligand. The complexes show a major static contribution to the overall interaction, …

Salmonella typhimuriumDenticityLightFísico-Química Ciencia de los Polímeros ElectroquímicaPhenanthrolineLigands01 natural sciences//purl.org/becyt/ford/1 [https]chemistry.chemical_compound22'-DipyridylStereochemistryCoordination ComplexesELECTRON TRANSFERSinglet OxygenCiencias QuímicasRHENIUMQuímicaChemistryRheniumPhotosensitizationPHOTOSENSITIZATIONAdductOxidation-ReductionCIENCIAS NATURALES Y EXACTASStereochemistryDNA damagePhenanthrolinePhenazineDNA CLEAVAGELigand010402 general chemistryCatalysisAdductElectron transferElectron transferAlkaloidsOxidants PhotochemicalPhenazine//purl.org/becyt/ford/1.4 [https]010405 organic chemistryLigandMutagenicity TestsDna cleavageOrganic ChemistryDenticityGeneral ChemistryDNA0104 chemical scienceschemistryALKALOIDSReactive Oxygen SpeciesDNACarbolinesDNA Damage
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Photochemical sample treatment for extracts clean up in PCB analysis from sediments.

2013

Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical sample treatment represents an alternative methodology for extracts clean up allowing for a reduction of the used amount of organic solvents. The first application of a photochemical sample treatment for the selective removal or reduction of organic substances interfering with PCBs analyses in sediments is reported. The method's efficiency and robustness were compared with currently used chromatographic purification. Quality parameters such as recovery, linearity and reproducibility were studied. The entire procedure was validated…

Sample purificationReproducibilityGeologic SedimentsChromatographyPCBChemistryPhotochemistrySample (material)PCB Photochemical sampletreatment Sediment Clean up UV irradiationUV irradiationSedimentReplicatePhotochemistryPolychlorinated BiphenylsGas Chromatography-Mass SpectrometryAnalytical ChemistryClean-upCongenerEnvironmental chemistryClean upSettore CHIM/01 - Chimica AnaliticaSedimentGas chromatography–mass spectrometryPhotochemical sampletreatmentTalanta
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