Search results for "MASS SPECTROMETRY"

showing 10 items of 2544 documents

Varying chiral ratio of Pinic acid enantiomers above the Amazon rainforest

2023

Chiral chemodiversity plays a crucial role in biochemical processes such as insect and plant communication. However, the vast majority of organic aerosol studies do not distinguish between enantiomeric compounds in the particle phase. Here we report chirally specified measurements of secondary organic aerosol (SOA) at the Amazon Tall Tower Observatory (ATTO) at different altitudes during three measurement campaigns at different seasons. Analysis of filter samples by liquid chromatography coupled to mass spectrometry (LC-MS) has shown that the chiral ratio of pinic acid (C9H14O4) varies with increasing height above the canopy. A similar trend was recently observed for the gas-phase precursor…

540 Chemistry and allied sciencesAtmospheric ScienceChemistryPhase (matter)540 ChemieAnalytical chemistryParticleMoleculeDegradation (geology)ParticulatesEnantiomerMass spectrometryAerosol
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Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid – a mass spectrometric study of SOA aging

2012

Abstract. This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pine…

540 Chemistry and allied sciencesAtmospheric ScienceChromatographyChemistryAtmospheric-pressure chemical ionizationFraction (chemistry)Mass spectrometryMass spectrometriclcsh:QC1-999JGas phaseAerosollcsh:ChemistryAcid oxidationlcsh:QD1-999540 ChemieYield (chemistry)ddc:550lcsh:PhysicsAtmospheric Chemistry and Physics
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Nanoparticles in the Biological Context: Surface Morphology and Protein Corona Formation

2020

Small 16(39), 2002162 (2020). doi:10.1002/smll.202002162

540 Chemistry and allied sciencesMaterials scienceMorphology (linguistics)Shell (structure)NanoparticleContext (language use)Protein Corona02 engineering and technology010402 general chemistry01 natural sciencesMass SpectrometryBiomaterialsColloidCorona (optical phenomenon)General Materials ScienceBackground subtractionBlood ProteinsGeneral Chemistry021001 nanoscience & nanotechnology5400104 chemical sciencesChemical physics540 Chemieddc:540NanoparticlesProtein Corona0210 nano-technologyBiotechnology
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The maximum carbonyl ratio (MCR) as a new index for the structural classification of secondary organic aerosol components

2021

RATIONALE Organic aerosols (OA) account for a large fraction of atmospheric fine particulate matter and thus are affecting climate and public health. Elucidation of the chemical composition of OA is the key for addressing the role of ambient fine particles at the atmosphere-biosphere interface and mass spectrometry is the main method to achieve this goal. METHODS High-resolution mass spectrometry (HRMS) is on its way to becoming one of the most prominent analytical techniques, also for the analysis of atmospheric aerosols. The combination of high mass resolution and accurate mass determination allows the elemental compositions of numerous compounds to be easily elucidated. Here a new parame…

540 Chemistry and allied sciencesResolution (mass spectrometry)Chemistry010401 analytical chemistryOrganic ChemistryAnalytical chemistryFraction (chemistry)Structural classificationParticulatesOrbitrapMass spectrometry01 natural sciences0104 chemical sciencesAnalytical ChemistryAerosollaw.inventionlaw540 ChemieChemical compositionSpectroscopyRapid Communications in Mass Spectrometry
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Design, characterization, and first field deployment of a novel aircraft-based aerosol mass spectrometer combining the laser ablation and flash vapor…

2021

In this paper, we present the design, development, and characteristics of the novel aerosol mass spectrometer ERICA (ERC Instrument for Chemical composition of Aerosols; ERC – European Research Council) and selected results from the first airborne field deployment. The instrument combines two well-established methods of real-time in situ measurements of fine particle chemical composition. The first method is the laser desorption and ionization technique, or laser ablation technique, for single-particle mass spectrometry (here with a frequency-quadrupled Nd:YAG laser at λ = 266 nm). The second method is a combination of thermal particle desorption, also called flash vaporization, and electro…

624 Civil engineering540 Chemistry and allied sciencesAtmospheric ScienceLaser ablationMaterials sciencebusiness.industry530 Physics624 Ingenieurbau und UmwelttechnikLaserMass spectrometry530 Physik620 Ingenieurwissenschaften und MaschinenbauAerosollaw.inventionOpticslaw540 ChemieVaporization620 Engineering and allied operationsParticleVacuum chamberParticle size600 Technikbusiness600 Technology (Applied sciences)Atmospheric Measurement Techniques
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Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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Charged jet cross section and fragmentation in proton-proton collisions at √s = 7 TeV

2019

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. We report the differential charged jet cross section and jet fragmentation distributions measured with the ALICE detector in proton-proton collisions at a center-of-mass energy √s=7  TeV. Jets with pseudorapidity |η|40  GeV/c, the pythia calculations also agree with the measured charged jet cross section. pythia6 simulations describe the fragmentation distributions to 15%. Larger discrepancies are observed for pythia8. SCOAP

:Kjerne- og elementærpartikkelfysikk: 431 [VDP]Physics and Astronomy (miscellaneous)fragmentation [jet]Astrophysics::High Energy Astrophysical Phenomenameasured [cross section]transverse momentumhiukkasfysiikka01 natural sciencesscattering [pp]Nuclear physicsALICEFragmentation (mass spectrometry)0103 physical sciencesjet fragmentation010306 general physicsNuclear ExperimentPhysicsQuantum chromodynamicsPP COLLISIONSta114010308 nuclear & particles physicsPB COLLISIONS:Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431 [VDP]TRANSVERSE-MOMENTUMVDP::Kjerne- og elementærpartikkelfysikk: 431resolution16. Peace & justicecharged particlejet cross sectionCharged particleNATURAL SCIENCES. Physics.ddc::Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431 [VDP]PRIRODNE ZNANOSTI. Fizika.:Nuclear and elementary particle physics: 431 [VDP]pp: scattering ; jet: fragmentation ; cross section: measured ; transverse momentum ; charged particle ; resolution ; PYTHIA ; ALICEVDP::Nuclear and elementary particle physics: 431PseudorapidityTransverse momentumPYTHIAHigh Energy Physics::Experimentproton-proton collisionsTRANSVERSE-MOMENTUM; PP COLLISIONS; PB COLLISIONS; PARTICLEPARTICLEPhysical Review D
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Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo

2021

Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1) is significantly hindering effective cancer chemotherapy. However, currently, no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically, mainly due to the inhibitor specificity, toxicity, and drug interactions. Here, we reported that three polyoxypregnanes (POPs) as the most abundant constituents of Marsdenia tenacissima (M. tenacissima) were novel ABCB1-modulatory pro-drugs, which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites. The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells v…

ABCC1 ATP binding cassette subfamily C member 1IC50 half maximal inhibitory concentrationMultidrug resistancePharmacologyNADPH reduced nicotinamide adenine dinucleotide phosphateF bioavailabilitychemistry.chemical_compoundPCR polymerase chain reaction0302 clinical medicineMDR multidrug resistanceECL electrochemiluminescencet1/2 elimination half-lifeLC–MS liquid chromatography coupled with mass spectrometryN.D. not detectedGeneral Pharmacology Toxicology and PharmaceuticsBBB blood–brain barriermedia_commonATF3 activating transcription factor 30303 health sciencesChemistryABC ATP-binding cassetteNMPA National Medical Products AdministrationPXR pregnane X receptorSDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresisHBSS Hankʹs balanced salt solutionABCB1Combination chemotherapyProdrugMarsdenia tenacissimaCmax peak concentrationPaclitaxelGAPDH glyceraldehyde-3-phosphate dehydrogenase030220 oncology & carcinogenesisBHI brain heart infusionOriginal ArticleAUC0–∞ area under plasma concentration vs. time curveMRT mean residence timeDrugmedia_common.quotation_subjectRM1-950Vd volume of distributionABCB1 ATP binding cassette subfamily B member 1UIC-2 mouse monoclonal ABCB1 antibodyABCG2 ATP binding cassette subfamily G member 2Combination chemotherapyCYP cytochrome P450 isozymePI propidium iodideTEER transepithelial electrical resistance03 medical and health sciencesPBS phosphate buffer salineFBS fetal bovine serumDox doxorubicinIn vivoPOP polyoxypregnanemedicine030304 developmental biologyEVOM epithelial tissue voltohmmeterTmax time for peak concentrationCancerLBE lowest binding energyPE phycoerythrinmedicine.diseaseMultiple drug resistancePolyoxypregnanePapp apparent permeabilityN.A. not applicableCancer cellH&E hematoxylin and eosinMDR1a multidrug resistance protein 1aTherapeutics. PharmacologyqPCR quantitative PCRM. tenacissima Marsdenia tenacissimaCL clearanceSD standard derivationActa Pharmaceutica Sinica B
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Metabolic signatures across the full spectrum of non-alcoholic fatty liver disease.

2022

Funder: European Commission

ALTtype 2 diabetes mellitusROC receiving operator characteristicaspartate aminotransferaseHSDLDL low-density lipoproteinUHPLC ultrahigh-performance liquid chromatographyROCHCCNon-alcoholic steatohepatitisGCPCANASHGastroenterology2-HB 2-hydroxybutanoic acid; 3-HB 3-hydroxybutanoic acid; ALT alanine aminotransferase; AST aspartate aminotransferase; CE cholesterol ester; Cer ceramide; FFA free fatty acid; FLIP Fatty Liver Inhibition of Progression; Fibrosis; GC gas chromatography; HCC hepatocellular carcinoma; HSD honest significant difference; LC lipid cluster; LDL low-density lipoprotein; LM lipid and metabolite; LMC lipid metabolite and clinical variable; LPC lysophosphatidylcholine; Lipidomics; Mass spectrometry; Metabolomics; NAFL non-alcoholic fatty liver; NAFLD non-alcoholic fatty liver disease; NAS NASH activity score; NASH non-alcoholic steatohepatitis; NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network; NRR non-rejection rate; Non-alcoholic steatohepatitis; PC(O) ether PC; PC phosphatidylcholine; PCA principal component analysis; PE phosphatidylethanolamine; QTOFMS quadrupole-time-of-flight mass spectrometry; ROC receiving operator characteristic; SAF steatosis activity and fibrosis; SM sphingomyelin; T2DM type 2 diabetes mellitus; TG triacylglycerol; UHPLC ultrahigh-performance liquid chromatographySAFSAF steatosis activity and fibrosisLM lipid and metabolitehonest significant differenceHSD honest significant differenceTG triacylglycerolnon-rejection ratecholesterol esterPCPEGC gas chromatographyfree fatty acidFLIPNASH non-alcoholic steatohepatitisNIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkBIOMARKERST2DMPE phosphatidylethanolamineLDLlipidNAFLDFFA free fatty acid2-HBMetabolomicsNAFL non-alcoholic fatty liverLMCphosphatidylcholineScience & TechnologySM sphingomyelinGastroenterology & HepatologyMass spectrometryactivitynutritional and metabolic diseasesT2DM type 2 diabetes mellitusACIDSreceiving operator characteristicdigestive system diseasesquadrupole-time-of-flight mass spectrometryLC lipid clusterlow-density lipoproteinNAS2-HB 2-hydroxybutanoic acidNAS NASH activity scoreQTOFMSether PCNRRSCORING SYSTEMprincipal component analysisgas chromatographyLC2-hydroxybutanoic acidPROGRESSIONAST aspartate aminotransferaseLMPC phosphatidylcholinePC(O)MARKERSUHPLCsteatosisTOOLImmunology and AllergyINSULIN-RESISTANCECerSMFatty Liver Inhibition of Progressionhepatocellular carcinoma2-HB 2-hydroxybutanoic acid NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network NRR non-rejection rate Non-alcoholic steatohepatitis PC(O) ether PC PC phosphatidylcholine PCA principal component analysis PE phosphatidylethanolamine QTOFMS quadrupole-time-of-flight mass spectrometry ROC receiving operator characteristic SAF steatosis activity and fibrosis SM T2DM type 2 diabetes mellitus TG triacylglycerol UHPLC ultrahigh-performance liquid chromatographyultrahigh-performance liquid chromatographyCELPC3-HBNAFLnon-alcoholic fatty liverTGtriacylglycerolNRR non-rejection rateLife Sciences & BiomedicineNAFLD non-alcoholic fatty liver diseaseFLIP Fatty Liver Inhibition of Progressionalanine aminotransferasemetaboliteCer ceramideCE cholesterol estersphingomyelinlysophosphatidylcholineand fibrosisALT alanine aminotransferaseInternal MedicineceramideNational Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkAST3-HB 3-hydroxybutanoic acidQTOFMS quadrupole-time-of-flight mass spectrometryPCA principal component analysisLPC lysophosphatidylcholineHepatologynon-alcoholic fatty liver diseaseand clinical variablePC(O) ether PC3-hydroxybutanoic acidFibrosisNASH activity scoreNIDDK NASH-CRNlipid clusterlipid and metabolitephosphatidylethanolamineLipidomicsLMC lipid metabolite and clinical variableFFAHCC hepatocellular carcinomaJHEP reports : innovation in hepatology
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Collision induced decomposition of AOT5YB2+: an unespected intracluster rearrangment

2014

AOT Yb cluster mass spectrometry gas phase rearrangment
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