Search results for "PAV"

showing 10 items of 368 documents

Synthesis of alkaloids by Stevens rearrangement of nitrile-stabilized ammonium ylides: (±)-laudanosine, (±)-laudanidine, (±)-armepavine, (±)-7-methox…

2013

The Stevens rearrangement of nitrile-stabilized ammonium ylides in conjunction with the reductive removal of the nitrile function permits the facile construction of α-branched amines from α-aminonitriles. We employed this reaction sequence for the preparation of (±)-laudanosine, (±)-laudanidine and (±)-armepavine, (±)-7-methoxycryptopleurine, and (±)-xylopinine from two closely related and readily accessible bicyclic α-aminonitriles. The final products were obtained in high to almost quantitative yields (71–98%) from the quaternary ammonium salts obtained by N-alkylation of these starting materials.

NitrileBicyclic moleculeMolecular StructureArmepavineOrganic ChemistryBerberine AlkaloidsStereoisomerismIsoquinolinesBenzylisoquinolinesLaudanosineQuaternary Ammonium Compoundschemistry.chemical_compoundchemistryStevens rearrangement7-methoxycryptopleurineNitrilesXylopinineOrganic chemistryAmmoniumQuinolizinesThe Journal of organic chemistry
researchProduct

Zvaigžņotā Debess: 2004/05, Ziema

2004

Contents: Ņ.Ozoliņa. Earthquakes in Latvia ; I.Daube. Space Craft “Ranger-7” ; M. Gailis. Moon Investigation in Riga ; J.Tambergs. Problems of Dialogue between Quantum Mechanics and Theology (concluded) ; Z Alksne, A.Alksnis. Ultra-Cool Dwarf Pair Weighed ; A.Balklavs. Successful Hunt of Protostars ; A.Balklavs. Silhouette of a Black Hole ; A.Balklavs. A Distant Giant Quasar ; A.Balklavs. Cosmic Objects in Captivating Photos – 3 ; J.Freimanis. Extragalactic Planetary Nebulae ; J.Jaunbergs. Cassini Enters the Saturnian System ; D.Krieviņš. Space Launchers of Early XXI Century. The Commonwealth of Independent States (CIS) ; J.Bārzdiņš. Professor Rusins-Martins Freivalds on the Path of Science…

Novembra kāvi Baltijas debesīsGalēji auksto punduru sistēma 2MASSW J0746425+2000321Herbiga-Haro objekti HH-30 HH-34 HH-47Krustvārdu mīklaLīgatnes meteorīts – hipotēzeProtozvaigznesPlanetārie miglāji – NGC 2392 (Eskimosa miglājs) NGC 6369 (Spociņa miglājs)Starptautiskā komandu olimpiāde “Baltijas ceļš – 2003” – uzdevumu atrisinājumiRisina lasītājsNASA Genesis – Saules vēja paraugiLU profesors Rūsiņš-Mārtiņš FreivaldsZemestrīces LatvijāBlumbaha spoguļteleskops BSTPirmās galaktikasCassini misija Saturna sistēmāJakobs Juliuss ZeibotsJupitera pavadoņa Jo putekļiRīgas topogrāfiskā uzmērīšanaSavādnieki eksaktajās zinātnēs – Dž.Maksvels O.Sevisaids H.Hercs V.Pauli V.Heizenbergs B.Mandelbrots A.Vītols J.Vītols G.Šipovs A.AkimovsMeteorītu panspermijaPlanetārie miglāji N52 N66 N192 SMP93 Lielajā Magelāna MākonīVenēras un Merkura aizklāšanāsKosmiskie transportlīdzekļi – NVSAstronomiskās parādības - 2005Melnais caurums – siluetsKalenaisa – “Hebridu Stounhendža”Planētu redzamības kompleksā diagramma 2005Zvaigžņu lietus novembrīESA Smart-1Astronomiskās parādības - 2004Kvantu mehānika un teoloģijaMilzu kvazārs J1432+158Londonas universitātes Berkbeka koledža
researchProduct

Noziedzīgas pavēles un noziedzīga rīkojuma izpildīšana

2019

Noziedzīgas pavēles un noziedzīga rīkojuma izpildes institūta regulējums ir iekļauts Krimināllikuma III. nodaļas 34. pantā, starp citiem apstākļiem, kas izslēdz kriminālatbildību. Kā apstāklis, kas izslēdz kriminālatbildību tas paredz nesaukt pie kriminālatbildības personu, ja tiek izpildīti normā minētie atbildību izslēdzošie apstākļi. Pētījuma uzdevumi ir literatūras avotu izpēte par noziedzīgas pavēles un noziedzīga rīkojuma institūtu, tā vēsturisko attīstību, un regulējumu ārvalstu normatīvajos aktos. Noziedzīgas pavēles un noziedzīga rīkojuma institūtam ir nepieciešams plašāks skaidrojums, par pavēles un rīkojuma jēdzieniem, to atšķirībām, par pavēles vai rīkojuma noziedzīgo raksturu. …

Noziedzīga pavēleapstāklis kas izslēdz kriminālatbildībunoziedzīgs nodarījumsnoziedzīgs rīkojumsJuridiskā zinātne
researchProduct

Zvaigžņotā Debess: 1959, Ziema - Rudens

1959

ObservatorijasSaules sistēmaKosmoloģijaAstronomyPlanētasObservatoriesZvaigznes:NATURAL SCIENCES::Physics::Astronomy and astrophysics [Research Subject Categories]MeteoriAstrophysicsAstrofizikaAstronomijaCosmologyPlanetary systemsZemes mākslīgie pavadoņiKomētasAstronomijas vēsture
researchProduct

Seawater carbonate chemistry and percentage cover of macroalgal species at three locations at Vulcano, Italy

2017

Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3- use (delta 13C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3- and CO2 had greater CO2 use as concentrations increased. Th…

Ocean Acidification International Coordination Centre (OA-ICC)TemperateRegistration number of speciesSalinityCaulerpa proliferaCommunity composition and diversityBicarbonate ion standard deviationUdotea petiolatainorganicAlkalinity total standard deviationAlkalinitySargassum muticumDictyota dichotomaHalopteris scopariaYearsCystoseira brachycarpaExperimentTemperature waterCarbon inorganic dissolvedCystoseira foeniculaceaCaulerpa racemosaCalculated using seacarb after Nisumaa et al 2010Cystoseira foeniculataAragonite saturation stateAlkalinity totaltotalCO2 ventpHTemperaturedissolvedCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Acetabularia acetabulumJania rubensCarbon dioxide standard deviationEarth System Researchδ13CLipid contentstandard deviationField observationUniform resource locator link to referenceCystoseira crinitaCoverageCalcite saturation stateLocationwaterSiteRocky-shore communityFigureBenthosUniform resource locator/link to referenceOcean Acidification International Coordination Centre OA ICCMediterranean SeaCarbon inorganic dissolved standard deviationTypeBicarbonate ionDictyopteris polypodioidesDilophus fasciolaCalculated using seacarb after Nisumaa et al. (2010)SpeciesCystoseira compressaEvent labelCarbonate system computation flagpH standard deviationCarbonate ion standard deviationMassFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonOxygenPartial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideRocky shore communityEntire communityFugacity of carbon dioxide water at sea surface temperature wet airPadina pavonicaSeasonδ13C standard deviationCoast and continental shelfCodium bursaTableCystoseira barbarta
researchProduct

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
researchProduct

Il teatro orientale

2004

Ombre indianeKeralaTeatro di figuraMarionette giapponesiMarionette orientaliPavakathakaliBunraku
researchProduct

Zvaigžņotā Debess: 2017, Rudens (237)

2017

Contents: “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: U.Dzērvītis. Dispute on Hubble’s Constant Value (abridged) ; E.Mūkins. Ten «Venera»’s: Devices, Journeys and Results (abridged) ; DEVELOPMENTS in SCIENCE: K.Schwartz. New Discoveries in the Orion Molecular Cloud Complex ; SPACE RESEARCH and EXPLORATION: J.Jaunbergs. Salty Emanations of Enceladus ; R.Misa. Voyager: the Longest and Farthest ; OBSERVATORIES and INSTRUMENTS: J.Kuzmanis. Dragon Looks at the Sky ; K.Salmiņš. On ILRS Technical Workshop 2017 in Riga ; CONFERENCES and MEETINGS: M.Sudārs. Trends of Space Infrastructure Development in Europe ; M.Gills. Congress of European Planetary Science 2017 in Riga ; FLASHBACK: N.Cimahoviča. On Whirl…

Oriona Molekulāro Mākoņu KomplekssLatvijas un Igaunijas praktikanti LU Astronomijas institūtāCERN zinātnes nedēļa LatvijāUrāna rotācijas virziens – lasītāja jautājumsKosmosa infrastruktūra – tendences Eiropā iespējas LatvijāLatvijas 45.atklātā skolēnu astronomijas olimpiādeZondes Voyager – intervija ar Projekta izpildītājiemLPSR ZA Radioastrofizikas observatorijai – 50ILRS lāzerlokācijas konference Rīgā:NATURAL SCIENCES::Physics::Astronomy and astrophysics [Research Subject Categories]VAĢB Latvijas nodaļai – 70Latvijas 67.matemātikas olimpiāde – uzdevumu atrisinājumiSaturna ledus pasaule Encelāds – Cassini pētījumiLatvijas 41.skolēnu zinātniskā konferenceFAST – Ķīnas 500 m stacionārais radioteleskopsEiropas Planetoloģijas kongress RīgāLatvijas Zemes mākslīgais pavadonis «Venta-1»Debess spīdekļi – 2017.gada rudensDzintaram Blūmam – 70Asteroīds (457743) Balklavs = 2009 HW20Mīkla “Kas ir šis majors?” – atminējumsSaules koronas virpuļi – ietekme uz Zemi
researchProduct

I nuovi mosaici pavimentali della Caupona del dio Pan a Ostia antica e l'architettura d'interni nel III sec. d.C.

2016

International audience

Ostia antica; architettura romana e tardo romana; pavimenti musivi; approvvigionamento idrico[SHS.ARCHEO] Humanities and Social Sciences/Archaeology and PrehistoryArchéologie[SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory[ SHS.ARCHEO ] Humanities and Social Sciences/Archaeology and Prehistorypavimenti musiviOstia anticaarchitettura romana e tardo romanaapprovvigionamento idricoComputingMilieux_MISCELLANEOUS
researchProduct

Die direkte quantitative Auswertung von Dünnschichtchromatogrammen durch Remissions- und Fluoreszenzmessungen 3. Mitt.: Bestimmung von Morphin, Codei…

1971

Es wird ein Verfahren zur quantitativen Bestimmung verschiedener Opiumalkaloide nebeneinander beschrieben, das auf der direkten Auswertung von DC durch Remissionsmessung mit Hilfe eines Chromatogramm-Spektralphotometers beruht. Anstelle des bisher ublichen Messpaltes wurde fur die Auswertung eine Kreisblende benutzt. Hierbei ist vorteilhaft, das die Form der Absorptions-Orts-Kurven keinen Einflus auf die Mesgenauigkeit besitzt, da nur die Peakhohe ausgewertet wird. Quantitative Determination of Opium Alkaloids A method for the quantitative determination of a number of single alkaloids in opium alkaloid mixtures is described, which is based on the direct evaluation of TLC by reflectance with…

PapaverineThebaineChromatographyOpium alkaloidsChemistryAlkaloidCodeinePharmaceutical ScienceOpiumThin-layer chromatographyDrug DiscoverymedicineMorphinemedicine.drugArchiv der Pharmazie
researchProduct