Search results for "Titration"

showing 10 items of 312 documents

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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Decline in Coccolithophore Diversity and Impact on Coccolith Morphogenesis Along a Natural CO2 Gradient

2014

A natural pH gradient caused by marine CO2 seeps off Vulcano Island (Italy) was used to assess the effects of ocean acidification on coccolithophores, which are abundant planktonic unicellular calcifiers. Such seeps are used as natural laboratories to study the effects of ocean acidification on marine ecosystems, since they cause long-term changes in seawater carbonate chemistry and pH, exposing the organisms to elevated CO2 concentrations and therefore mimicking future scenarios. Previous work at CO2 seeps has focused exclusively on benthic organisms. Here we show progressive depletion of 27 coccolithophore species, in terms of cell concentrations and diversity, along a calcite saturation …

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityCommunity composition and diversityinorganicAlkalinityCoccospheres malformedMediterranean Sea Acidification in a Changing Climate MedSeATemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateAlkalinity totaltotalCO2 ventpHPelagosTemperaturedissolvedCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Earth System ResearchmalformedField observationPotentiometric titrationCalcite saturation stateCoccospheresPotentiometricwaterGrowth MorphologyMediterranean Sea Acidification in a Changing Climate (MedSeA)Ocean Acidification International Coordination Centre OA ICCMediterranean SeaBicarbonate ionCalculated using seacarb after Nisumaa et al. (2010)Calculated using CO2SYSfungiCarbonate system computation flagCoccospheres corrodedFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonBiomass/Abundance/Elemental compositionPartial pressure of carbon dioxide water at sea surface temperature wet airSample IDCarbon dioxidecorrodedEntire communityGrowth/MorphologyPhytoplanktonFugacity of carbon dioxide water at sea surface temperature wet airBiomass Abundance Elemental compositionCoast and continental shelfNumber of species
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Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea Off vulcano, Italy

2014

The effects of increasing atmospheric CO(2) on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO(2) gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 µatm, minimum Omega (arag) 3.77), moderately CO(2)-enriched (median pCO(2) 592 µatm, minimum Omega (arag) 2.96), and highly CO(2)-enriched (median pCO(2) 1611…

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityPotentiometric titrationCalcite saturation stateCommunity composition and diversityPotentiometricinorganicwaterAlkalinitySiteFigureBenthosTemperature waterCarbon inorganic dissolvedAbundanceCalculated using seacarb after Nisumaa et al 2010Ocean Acidification International Coordination Centre OA ICCMediterranean SeaBicarbonate ionAragonite saturation stateSoft-bottom communityAlkalinity totalLONGITUDEtotalCalculated using seacarb after Nisumaa et al. (2010)CO2 ventSpeciesShannon Diversity IndexpHCalculated using CO2SYSTemperatureCarbonate system computation flagdissolvedFugacity of carbon dioxide (water) at sea surface temperature (wet air)Carbonate ionCarbonPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Partial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideSoft bottom communityEntire communityEarth System ResearchLATITUDEFugacity of carbon dioxide water at sea surface temperature wet airGroupCoast and continental shelfField observationClass
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Binding of fluoride and carbonate by open chain polyammonium cations

2004

The formation of open chain polyammonium cation-fluoride and -carbonate complexes was studied by potentiometric and calorimetric techniques at t=25 degrees C. Several species of H(i)AL (A=amine; L=F(-), CO(3)(2-)) are formed in both systems with a mean stability log K=1.0zeta (zeta=|z(anion)xz(cation)|) and log K=2.0zeta for fluoride and carbonate, respectively. The comparison with analogous systems (chloride and acetate for fluoride and hydrogenphosphate, sulfate and malonate for carbonate) showed that fluoride and carbonate form the most stable species with open chain polyammonium cations, among low molecular weight anions. The N-alkyl substitution does not play negligible role in the sta…

Open chain polyammonium cationCarbonatePotentiometric titrationInorganic chemistryComplex formationCalorimetryThermodynamic parametersMedicinal chemistryChlorideAnalytical Chemistrychemistry.chemical_compoundMalonatechemistryPotentiometrymedicineCarbonateSettore CHIM/01 - Chimica AnaliticaAmmoniumAmine gas treatingSulfateFluorideFluorideAnion coordination chemistrymedicine.drugTalanta
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Dosing fentanyl buccal tablet for breakthrough cancer pain: dose titration versus proportional doses.

2012

Abstract OBJECTIVES: The aim of this study was to compare the efficacy and safety of doses of fentanyl buccal tablet (FBT) proportional to doses of opioids used for background analgesia versus dose titration starting with the minimal dose for the management of breakthrough cancer pain (BTcP). METHODS: A total of 82 cancer patients with BTcP who were receiving strong opioids in doses of at least 60 mg of oral morphine equivalents and having acceptable background analgesia, were selected for a multicenter unblinded study. Forty-one patients were randomized to receive FBT in doses proportional to the daily opioid doses for four consecutive episodes of BTcP (group P). Forty-one patients underwe…

OralMaleDose titrationfentanyl buccal tabletAdministration OralOpioidDosing fentanylSettore MED/42 - Igiene Generale E ApplicataDose titrationlaw.inventionDose-Response RelationshipRandomized controlled triallawNeoplasmsFentanyl Buccal TabletMedicineHumansRapid onset opioidsDrug Dosage CalculationsCancer painAgedPain MeasurementAnalgesicsDose-Response Relationship DrugBreakthrough pain; Cancer pain; Dose titration; Fentanyl buccal tablet; Rapid onset opioids; Administration Oral; Aged; Analgesics Opioid; Breakthrough Pain; Dose-Response Relationship Drug; Female; Fentanyl; Humans; Male; Middle Aged; Neoplasms; Pain Measurement; Tablets; Titrimetry; Drug Dosage Calculations; Medicine (all)business.industryMedicine (all)Breakthrough PainTitrimetryCancerGeneral MedicineBuccal administrationfentanyl buccal tablet; breakthrough cancer pain; randomized clinical trialMiddle Agedmedicine.diseaserandomized clinical trialAnalgesics OpioidFentanylbreakthrough cancer painOpioidAnesthesiaAdministrationFemaleDrugbusinessCancer painmedicine.drugTabletsCurrent medical research and opinion
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Dialkylimidazolium dimethyl phosphates as solvents and catalysts for the Knoevenagel condensation reaction

2014

Abstract The reaction between benzaldehyde and ethyl cyanoacetate is investigated in 1,3-dialkylimidazolium salts as solvents. The impact of both ions in these ionic liquids on the yield of the condensation reaction product is examined. Potentiometric titrations are employed for quantitative analyses of the best ionic liquids, revealing these to be 1,3-dialkylimidazolium dimethyl phosphates.

Organic ChemistryPotentiometric titrationCondensation reactionBiochemistryCatalysisIonBenzaldehydechemistry.chemical_compoundchemistryYield (chemistry)Drug DiscoveryIonic liquidOrganic chemistryKnoevenagel condensationTetrahedron Letters
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Comparison of Different Classical and Instrumental Analysis Methods for Precise Quantification of Calcium and Phosphorous Ratio in Hydroxyapatite

2019

The largest comparison of analytical techniques, useful for calcium phosphates, has been conducted, presenting recommendations for quality control and research of calcium phosphates. Results from three classical quantification methods (gravimetry, titramety, photometry) and three instrumental measurement methods (XRF, FAAS ICP-OES) are reported to determine the most accurate, fastest and cheapest analysis method. Remarks are given for increasing the accuracy for each method and corrections made for adsorbed water. For routine analysis, a recommendation is given to ICP-OES for a fast analysis, together with a less frequent use of gravimetry to validate the results and provide a periodic cros…

Photometry (optics)ChromatographychemistryMechanics of MaterialsMechanical Engineeringchemistry.chemical_elementGeneral Materials ScienceTitrationGravimetryCalciumAnalysis methodKey Engineering Materials
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Solid Contact Potentiometric Sensors Based on a New Class of Ionic Liquids on Thiacalixarene Platform

2018

New solid-contact potentiometric sensors have been developed for hydrogen phosphate recognition on the basis of ionic liquids containing tetrasubstituted derivatives of thiacalix[4]arene in cone and 1,3-alternate conformations with trimethyl- and triethylammonium fragments at the lower rim substituents. The recognition of selected anions including carbonate, hydrogen phosphate, perchlorate, oxalate, picrate, and EDTA was conducted using electrochemical impedance spectroscopy with ferricyanide redox probe. For the potentiometric sensor assembling, the ionic liquids were stabilized by multiwalled carbon nanotubes and carbon black deposited on the glassy carbon electrode. The influence of supp…

PicratePotentiometric titrationInorganic chemistry02 engineering and technology01 natural sciencesOxalatelcsh:Chemistrychemistry.chemical_compoundPerchloratePotentiometric sensorThiacalixareneOriginal Researchionic liquidsolid-contact potentiometric sensorcarbon nanotubes010401 analytical chemistrythiacalix[4]areneGeneral Chemistry021001 nanoscience & nanotechnology0104 chemical sciencesChemistryphosphate determinationchemistrylcsh:QD1-999Ionic liquidFerricyanide0210 nano-technologyFrontiers in Chemistry
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1990

It is shown that the block-like structure of the polyampholyte poly(methacrylic acid)-block-poly(1-methyl-4-vinylpyridinium chloride) considerably influences its conformational behaviour. This specific behaviour is explained by the formation of intra-macromolecular polyelectrolyte complexes stabilized by cooperative ionic contacts between acidic and basic units near the isoelectric point (i. e. p.). The structure of the block-polyampholyte at the i. e. p. is suggested to be close to the structure of non-stoichiometric polyelectrolyte complexes. The complex formation ability of the block-polyampholyte with respect to anionic, cationic, and nonionic polymers is also studied. By means of poten…

Poly(methacrylic acid)chemistry.chemical_compoundAqueous solutionMethacrylic acidChemistryPotentiometric titrationPolymer chemistrymedicineCationic polymerizationChlorideDissociation (chemistry)Polyelectrolytemedicine.drugDie Makromolekulare Chemie
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