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21Author    Ryuichi Ishii, GeorgH. SchmidRequires cookie*
 Title    The Kok Effect and Its Relationship to Photorespiration in Tobacco  
 Abstract    The Kok effect of photosynthesis was investigated in different tobacco mutants. It was found that the breaks in the light intensity curve were always at or around 1000 lux in all plants tested regardless o f the unit sizes which differed by a factor of 10. It was concluded that the photo­ receptor responsible for the effect must be present in the wild type and the chlorophyll deficient mutants in the same amount and is probably not chlorophyll. Due to the fact that the light dependency of the Hill reaction in isolated tobacco chloroplasts also shows a break at or around the "Kok intensity" it was concluded that probably a structural change of the photochemical apparatus around 1000 lux contributes to the effect. Measurement of 180 2-uptake by mass spectrometry at low light intensity shows at low C 0 2-concentration an enhancement of 180 2-uptake again at/around 1000 lux indicating that photorespiration starts to function at the "Kok intensity". Due to the fact that 180 2-uptake remains constant at high C 0 2-concentrations the break in the photosynthetic light intensity curve cannot be due to an inhibition o f "dark respiration" at low light intensities. 
  Reference    Z. Naturforsch. 36c, 450 (1981); received February 26 1981 
  Published    1981 
  Keywords    Kok Effect, Tobacco Mutants, 180 2-Uptake, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0450.pdf 
 Identifier    ZNC-1981-36c-0450 
 Volume    36 
22Author    P. He, K. P. Bader, A. Radunz, G. H. SchmidRequires cookie*
 Title    Consequences of High C 0 2-Concentrations in Air on Growth and Gas-Exchange Rates in Tobacco Mutants  
 Abstract    Wild type tobacco N. tabacum var. John William's Broadleaf and the tobacco aurea mutant Su/su were permanently grown under 700 ppm C 0 2 in air. In comparison to plants grown under 350 ppm C 0 2 in air but under otherwise identical conditions growth was substantially enhanced. Gas exchange measurem ents carried out by mass spectrometry show that the rate of photosynthesis in the wild type and in the mutant is increased by more than 100%. The photorespiratory rate in the wild type measured as 180 2-uptake in the light in the "700 ppm C 0 2-plants" is not reduced to the extent expected or deduced from experiments in which the 350 ppm system responds under in vitro conditions to 700 ppm C 0 2. An analysis of the induction kinetics of room tem perature fluorescence kinetics of the adapted (700 ppm C 0 2) system and the control system (350 ppm C 0 2) under various C 0 2-partial pressures shows that perm anent growth under the elevated C 0 2-partial pressure leads to a structural modifi­ cation of the photosynthetic apparatus. 
  Reference    Z. Naturforsch. 50c, 781—788 (1995); received July 3/July 30 1995 
  Published    1995 
  Keywords    High C 0 2-Pressure, Mass Spectrometry, Tobacco, Photosynthesis, Photorespiration 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0781.pdf 
 Identifier    ZNC-1995-50c-0781 
 Volume    50 
23Author    Helmut Schwarz, Chrysostomos Wesdemiotis, Thomas Weiske, Klaus-Peter Zeller, Roland MüllerRequires cookie*
 Title    H. Schwarz et al. * Methyl-Eliminierung aus dem metastabilen Homoadamantan-Radikalkation 219 Methyl Loss from Metastable Homoadamantane Cation Radical  
 Abstract    It is demonstrated that methyl loss from ionized homoadamantane (1) yields exclusively the 1-adamantyl cation (4); there is no experimental evidence for the formation of the secondary adamantyl cation (5). From both model calculations and the investigation of [4-13 C]-homoadamantane (la) and l(13 C-methyl)adamantane (2a) it is concluded, that 24% of the metastable homoadamantane cation radicals dissociate after one isomerization (1 2); the remaining 76% are able to undergo at least a second (degenerate) isomerization cycle (2->l->2) prior to methyl loss. 78% of metastable 1-methyl-adamantane cation radical, obtained upon direct ionization of the corresponding neutral hydrocarbon, dissociate directly, whereas the loss of methyl from the remaining 22% is preceded by an isomerization 2 ->1 ->2. 
  Reference    Z. Naturforsch. 35b, 207—211 (1980); eingegangen am 23. Oktober 1979 
  Published    1980 
  Keywords    Ion Structures, Carbocation Rearrangements, Hydrocarbon Chemistry, Mass Spectrometry, Collisional Activation 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0207.pdf 
 Identifier    ZNB-1980-35b-0207 
 Volume    35 
24Author    Gerald Zon, YoungH. ChangRequires cookie*
 Abstract    Kinetic energy release measurements dem-onstrate that the loss of neutral HN, Et0C(0)N from the compounds investigated seems to occur by a symmetry allowed (1,1) elimination. lionized nitrenes are produced with only very low intensity. 
  Reference    (Z. Naturforsch. 33b, 129—130 [1978]; eingegangen am 10. Oktober 1977) 
  Published    1978 
  Keywords    Mass Spectrometry, Kinetic Energy Release, Orbital Symmetry, Cheletropic Reactions, Silyl Ether 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0129_n.pdf 
 Identifier    ZNB-1978-33b-0129_n 
 Volume    33 
25Author    W.I G Ruszeckia, K. Strzałk, K.P B Ad Erc, A. R. Adunzc, G. H. SchmRequires cookie*
 Title    Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II  
 Abstract    In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosyn­ thetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ ferent light quality and thylakoids having various levels o f xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means o f mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and o f light-induced oxygen uptake indicate that the de-epoxidation o f violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin. 
  Reference    Z. Naturforsch. 51c, 47 (1996); received September 22/O ctober 18 1995 
  Published    1996 
  Keywords    Xanthophyll Cycle, Cyclic Electron Flow, Photosystem II, Oxygen Evolution, Blue Light Effect, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0047.pdf 
 Identifier    ZNC-1996-51c-0047 
 Volume    51 
26Author    A. G. Oldbach1, F. H. Ensel1, K. R. Ad, Em An NRequires cookie*
 Title    Size-dependent Trends in the Scattering of Small Potassium Clusters by Water Molecules  
 Abstract    Scattering o f small potassium clusters by water molecules has been studied in a molecular beam experiment for the first time. In the size range up to eight atom s, trends for cross sections have been obtained by investigating low energy collisions. Significant differences in relative cross sections can be assigned to inelastic collisions. As in case o f scattering o f sodium clusters by argon (Goerke, A. et al., J. Chem. Phys. 98, 9653 (1993)), rotational excitation o f the clusters seems to be the dominating interaction. 
  Reference    Z. Naturforsch. 49a, 1067—1073 (1994); received September 28 1994 
  Published    1994 
  Keywords    Potassium clusters, Inelastic scattering, M olecular beam, Mass spectrometry, P hoto­ ionization 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1067.pdf 
 Identifier    ZNA-1994-49a-1067 
 Volume    49 
27Author    Heinz Egge, Uwe Murawski, Wirapong Chatranon, Fritz ZillikenRequires cookie*
 Title    eine gaschromatographisch-massenspektrometrische Analyse The Branched Chain Fatty Acids of Staphylococcus aureus, a Gas Chromato- graphic-Mass Spectrometric Analysis  
 Abstract    The fatty acid methylesters prepared by transesterification of the total lipid extract of Staphylo-coccus aureus Wood 46 were analysed by gas chromatography on thin film capillaries coated with polyphenylether (OS 138), siliconerubber (SE 30) and S.C.O.T. columns coated with Diethylene-glycoladipatepolyester (DEGA) in combination with mass spectrometry. Among the branched chain fatty acids ranging from Clt — C21, the iso-and anteiso-C15 acids are predominant. In the group of the C^ and C17 acids branching in position 9 and 10 was also found. No unsaturated branched chain fatty acids could be detected. Retention data and mass spectra of the branched chain fatty acids are presented. Die Neutrallipide, Phospholipide und Glycero-glykolipide der Staphylococcen enthalten einen gro-ßen Anteil verzweigter Fettsäuren, bei denen wo-und a/itewo-Fettsäuren vorherrschen 2 . Die quan-titative Verteilung der Lipide und der Fettsäuren ist 
  Reference    (Z. Naturforsch. 26b, 893—901 [1971]; eingegangen am 6. März 1971 revidiert am 18. Mai 1971) 
  Published    1971 
  Keywords    Staphylococcus aureus, Branched chain fatty acids, Gas chromatography, Capillary columns, Mass spectrometry 
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 TEI-XML for    default:Reihe_B/26/ZNB-1971-26b-0893.pdf 
 Identifier    ZNB-1971-26b-0893 
 Volume    26 
28Author    Bernd Richter, Helmut SchwarzRequires cookie*
 Title    Zur McLafferty-Umlagerung bei Radikalkationen von Phenylpyridylalkanonen [1] On the McLafferty Rearrangement of Ionized Phenyl Pyridyl Alkanones [1]  
 Abstract    A detailed investigation concerning the genesis of McLafferty rearrangement products from molecular ions of phenyl pyridyl alkanones reveals the following features: 1) The various products are not formed by competitive dissociations of the molecular ion. Most of the relevant fragment ions are generated from the primary McLafferty product of a hydrogen transfer to the ionized carbonyl group (M +> ->m/z 163, ion k). The ion k plays a decisive role for the generation of the abundant product ions at m/z 93 (ion g) and m/z 106 (ion s) both of which are formed by further dissociation of k. Details of the mechanisms for the decomposition of k are obtained by investigating [D]-labelled isotopomers, the analysis of low and high resolution data, the application of MIKE and CA spectra. The problem of keto/enol tautomerism between some ions, relevant in this context, is discussed and it is shown that these isomerization processes are not involved. A detaüed description is given for the syntheses of various [D]-labelled phenyl pyridyl alkanones. 
  Reference    Z. Naturforsch. 36b, 865—877 (1981); eingegangen am 16. Dezember 1980 
  Published    1981 
  Keywords    Mass Spectrometry, Hydrogen Rearrangement, Keto Enol Tautomerism, Metastable Ions, Collisional Activation 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0865.pdf 
 Identifier    ZNB-1981-36b-0865 
 Volume    36 
29Author    Wilfried Franke, Helmut Schwarz, Chrysostomos WesdemiotisRequires cookie*
 Title    Elf stabile C5H9+-Kationen in der Gasphase. Zur dissoziativen Ionisierung von 31 isomeren C6H9Br-Verbindungen Eleven Stable CsHo 4 " Cations in the Gas Phase. On the Dissociative Ionization of 31 Isomeric CsHgBr Compounds  
 Abstract    Collisional activation mass spectrometry (CA) reveals the existence of 11 stable CsH9+ cations in the gas phase, e. g. the substituted allyl cations a, b, c, d,and e, the sub-stituted vinyl cations f, g, h, and i, the methyl cyclobutyl cation j and the cyclopentyl cation k, respectively. The ethyl substituted allyl cation a is formed via dissociative ionization of the isomeric precursors 1, 3, 4, 5, 18, 19, 20, 22, and 28 by means of various mechanistic processes, whereas the 1,3-dimethylallyl cation b is generated from both 2 (by allylic cleavage) and in part from the stereoisomeric cyclopropan derivatives 25, 26 and 27. 6"l + -gives a mixture of the vinyl cations 1 and g. From 13 and 14 the main product generated is the 1,2-dimethylallyl cation d, which is formed directly from 11 and also by quite complicated processes from 13, 14 and to a certain extent from 25, 26 and 27. The dissociative ionization of 9, 15, 16, 21, 24 and (in part) 23 give rise to the formation of the substituted vinyl cation h. Decomposition of 23"!+ • results not only in formation of h but generates also the 1,1-dimethylallyl cation e. From 291+-and 30~l +-both the methylcyclo-butyl cation j and cyclopentyl cation k are produced, whereas the isomeric precursor 28 gives mainly the substituted allyl cation a and a second, as yet, unidentified CsH^ cation. In general, it can be stated that the gas phase chemistry of cation radicals of substituted cyclopropanes is characterised by multistep-reactions, commencing with spontaneous ring opening. The so formed intermediates undergo various rearrangements (including hydrogen and alkyl shifts) prior to expulsion of Br\ Direct elimination of Br' from intact cyclopropan-like structures, followed by ring opening of the intermediate cyclopropyl cation, cannot compete with the above-mentioned multistep-sequences. 
  Reference    Z. Naturforsch. 36b, 1315—1323 (1981); eingegangen am 2. Juni 1981 
  Published    1981 
  Keywords    Isolated Carbocations, Ion Structures, Gas Phase Ion Chemistry, Mass Spectrometry, Collisional Activation 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1315.pdf 
 Identifier    ZNB-1981-36b-1315 
 Volume    36 
30Author    Henryk Zegota++, Clemens Von SonntagRequires cookie*
 Title    Radical-Induced Dephosphorylation of Fructose Phosphates in Aqueous Solution +  
 Abstract    Oxygen free N20-saturated aqueous solutions of D-fructose-1-phosphate and D-fructose-6-phosphate were y-irradiated. Inorganic phosphate and phosphate free sugars (containing four to six carbon atoms) were identified and their G-values measured. D-Fructose-1-phosphate yields (G-values in parentheses) inorganic phosphate (1.6), hexos-2-ulose (0.12), 6-deoxy-2,5-hexodiulose (0.16), tetrulose (0.05) and 3-deoxytetrulose (0.15). D-Fructose-6-phosphate yields inorganic phosphate (1.7), hexos-5-ulose (0.1), 6-deoxy-2,5-hexodiulose (0.36), 3-deoxy-2,5-hexodiulose and 2-deoxyhexos-5-ulose (together 0.18). On treatment with alkaline phosphatase further deoxy sugars were re-cognized and in fructose-1-phosphate G(6-deoxy-2,5-hexodiulose) was increased to a G-value of 0.4. Dephosphorylation is considered to occur mainly after OH attack at C-5 and C-l in fructose-1-phosphate and at C-5 and C-6 in fructose-6-phosphate. Reaction mechanisms are discussed. 
  Reference    Z. Naturforsch. 36b, 1331—1337 (1981); received May 29 1981 
  Published    1981 
  Keywords    D-Fructo8e-l-phosphate, D-Fructose-6-phosphate, y-Irradiation, Radical Reactions, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1331.pdf 
 Identifier    ZNB-1981-36b-1331 
 Volume    36 
31Author    Gemot Frenking, Jochen Schmidt, Helmut SchwarzRequires cookie*
 Title    Quantenmechanische Berechnungen zu pseudo-einstufigen (C-C)-Spaltungen bei Radikalkationen von Carbonsäuren Quantum Mechanical Calculations on Pseudo-One-Step Cleavages of Carbonic Acid Cation Radicals  
 Abstract    Extensive quantum mechanical calculations on the unrestricted MINDO/3 level reveal that for some ionised carbonic acids the energetically most feasible pathway for uni-molecular C-C cleavage cannot be described as being a one-step process. In complete agreement with experimental results the computational data are consistent with an inter-pretation of the reaction as being a two-step process, in which the reaction commences with a hydrogen migration from a CH-bond onto the ionised C = 0 group. The dissociation is completed with a radical induced C-C cleavage thus generating quite stable protonated unsaturated carbonic acids. Whereas the MINDO/3 results clearly show that the two-step process is energetically favoured over the direct C-C cleavage, this computational method fails badly in explaining the experimentally established fact that in the two-step sequence the hydrogen migration is the rate-determining step. This failure is due to the MINDO/3 inherent weakness of overestimating the stability of cyclic ions, e.g. cyclic transition states as they are formed in the course of the hydrogen migration step. Single point ab initio calculations carried out on the 4-31G level substantiate this interpretation in that the transition state for the hydrogen migration is calculated to lie substantially higher than that for the actual C-C dissociation step, but is still much lower than that calculated for a direct simple bond cleavage process of the respective cation radical. 
  Reference    Z. Naturforsch. 37b, 355—360 (1982); eingegangen am 23. Oktober 1981 
  Published    1982 
  Keywords    Potential Energy Surfaces, Carbonic Acids, Hydrogen Rearrangement, C-C Cleavage, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-0355.pdf 
 Identifier    ZNB-1982-37b-0355 
 Volume    37 
32Author    Bernhard Ciommer, Helmut SchwarzRequires cookie*
 Title    Zur intermediären Existenz von Ethylenfluoronium-Ionen in der Gasphase On the Intermediary Existence of Gaseous Ethylen Fluoronium Ions  
 Abstract    The long-sought ethylen fluoronium ion (2) is generated as an intermediate in the dissociative ionization of l-fluoro-2-(^-methyl)phenoxy ethane (4). However, prior to collisionally induced dissociation 2 undergoes ring-opening, associated with hydrogen migration, to form 1-fluoroethyl cation (3). Other decomposition pathways of the molecular ions of 4 involve (i) direct formation of 3 via a combination of C-O-cleavage (loss of ArO -) and [1,2] hydrogen migration (18%) and (ii) complete positional loss of the a-and ß-methylene hydrogen atoms (34%). The remaining 48% of the molecular ions of 4 dissociate via anchimeric assistance of the fluorine in the elimination of ArO -, thus giving rise to the formation of 2. 
  Reference    Z. Naturforsch. 38b, 635—638 (1983); eingegangen am 23. Dezember 1982 
  Published    1983 
  Keywords    Fluoronium Ions, Neighbouring Group Participation, Gaseous Ions, Collisional Activation, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0635.pdf 
 Identifier    ZNB-1983-38b-0635 
 Volume    38 
33Author    B. V. Burger, Maritha Le Roux, C. F. Garbers, H.S C Spies, R. C. Bigalke, K.G R Pachler, P. L. Wessels, N.C R L, C.S I R, South Africa, V. Christ, K. H. MaurerRequires cookie*
 Title    Further Compounds from the Pedal Gland of the Bontebok ( Damaliscus dorcas dorcas)  
 Abstract    The identification of four further major constituents of the pedal gland exudate of the bontebok, Damaliscus dorcas dorcas, viz. a-terpineol, 2-ra-heptylpyridine, m-cresol and (Z)-6-dodecen-4-olide and the investigation of the stereochemistry of the double bond in (Z) -6-dodecen-4-olide by means of iterative computer analysis are described. An improved synthesis of this compound is outlined. Studies on Mammalian Pheromones, II The identification of 2-heptanone, 2-nonanone, 2-undecanone, 2,5-undecanedione and (Z)-5-undecen-2-one as some of the major volatile constituents of 
  Reference    (Z. Naturforsch. 32c, 49 [1977]; received July 14 1976) 
  Published    1977 
  Keywords    L Birkofer on His 65th Birthday Olfactory Communication, Pheromones, Mass Spectrometry, NMR Spectra Simulation, y-Lactone Synthesis 
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 TEI-XML for    default:Reihe_C/32/ZNC-1977-32c-0049.pdf 
 Identifier    ZNC-1977-32c-0049 
 Volume    32 
34Author    G. Erd GädeRequires cookie*
 Title    The Revolution in Insect Neuropeptides Illustrated by the Adipokinetic Hormone/Red Pigment-Concentrating Hormone Family of Peptides  
 Abstract    The last decade has seen a surge in the knowledge on primary structures of insect neuro­ peptides. Particularly successful were isolations and sequence determinations of more than 30 members of the adipokinetic horm one/red pigment-concentrating hormone (A K H /R P C H) family of peptides. This brief overview describes the techniques used to obtain data on purifi­ cation and structure such as high performance liquid chromatography, Edman sequencing and mass spectrometry. M oreover, a short account on the precursors and on the multiple functions of the peptides of the A K H /R P C H family in various crustacean and insect species is given. 
  Reference    Z. Naturforsch. 51c, 607 (1996); received April 8 /July 2 1996 
  Published    1996 
  Keywords    Insect Neuropeptides, R P -H P L C, Edm an Degradation, Mass Spectrometry, Bioassays 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0607.pdf 
 Identifier    ZNC-1996-51c-0607 
 Volume    51