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  • 1
    Electronic Resource
    Electronic Resource
    Photodissociation of rovibrationally excited C2H2: Observation of two pathways (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 385-391 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: C2H2 is prepared in the 2030000 (five quanta of C–H stretch) vibrational state and photodissociated by 243.135 nm photons that also probe the H photofragments via (2+1) resonance-enhanced multiphoton ionization (REMPI) in a time-of-flight mass spectrometer. The production of H atoms is greatly enhanced upon rovibrational excitation. The REMPI action spectrum shows the characteristic features of a Σu+–Σg+ band and mimics the absorption spectrum, except that the R(13) line intensity is an order of magnitude higher than that expected for a Boltzmann distribution. The maximum translational energy of the H atoms obtained from dissociation of the regularly distributed rotational states is 0.67±0.10, whereas for R(13) it is 1.34±0.10 eV. The observed intensities and linewidths indicate the existence of two photodissociation pathways following the preparation of C2H2, where the C2H fragment is produced in two different states. In the R(13) pathway an additional bent state is prepared, or an accidental coincidence resonance is involved. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474399
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  • 2
    Electronic Resource
    Electronic Resource
    Combination bands versus overtone stretch excitation and rotational effects in vibrationally mediated photodissociation of acetylene (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 8959-8967 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Rovibrational excitation combined with promotion of C2H2 molecules to the excited electronic trans-bent states A˜ 1Au/B˜ 1Bu and photofragment ionization are used to generate action spectra, H Doppler profiles, and time-of-flight mass spectra. Rovibrational states of C2H2 in the 15 480–15 723 cm−1 region are photodissociated by 243.135 nm photons that subsequently tag the H fragments. The H photofragment yield is greatly enhanced upon rovibrational excitation. In the action spectra, the intensities of the combination bands that involve high stretch and low bend excitation, (1410020) and (2031100), are close to that of the fourth overtone of the C–H stretch, (2030000), while in the absorption spectra the intensities of the combination bands are much weaker. In addition, the effect of rotation on fragment yield and dissociation channels is demonstrated. Several pairs of rotational transitions (sharing similar J′) stand out from the rotational band contour and the R(13) line of (2030000) shows an anomalously high intensity. The origin of the intensity enhancement for the combination bands is the better Franck–Condon (FC) overlap of states containing bend excitation with the dissociative wave functions. The source of the high intensity for the pairs of rotational transitions is the interaction with zero-order dark states that also give rise to a better FC factor, whereas in R(13) excitation an additional bent state is prepared, followed by two photon ultraviolet absorption, leading to a different photodissociation pathway. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477567
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of carbon supply on the stimulation of light-saturated photosynthesis by blue light in Laminaria saccharina: implications for the mechanism of carbon acquisition in higher brown algae (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In saturating irradiances of red light, photosynthesis of Laminaria saccharina (L.) Lamouroux was stimulated by low irradiances of continuous blue light only when the supply of dissolved inorganic carbon (DIC) was limiting. The degree of this stimulation was inversely proportional to the logarithm of the concentration of free CO2, whether this was adjusted by varying the total DIC or the pH at a given DIC concentration. The final pH reached in a closed system was higher in blue light than in red light. Both acetazolamide and ethoxyzolamide suppressed the responses to blue light almost completely, but reduced photosynthesis in red light by only 30%. Buffering the pH of the seawater also suppressed the stimulation of photosynthesis by blue light without affecting the photosynthetic rate in red light. The transient stimulation of O2 evolution by a blue light pulse was not accompanied by a corresponding increase in CO2 consumption. These observations could be explained if, in analogy to the mechanism proposed for Ectocarpus (Schmid, Mills & Dring 1996, Plant Cell and Environment 19,373–382, this issue, accompanying paper), photosynthesis was supported by a blue-light-activated release of CO2 from an internal store. We suggest that the store is located in the vacuoles of the cortical tissue of the blades. The main photosynthetic tissue, however, is in the overlying meristoderm, and blue-light-activated mobilization of the store could stimulate O2 evolution only if periplasmic carbonic anhydrase was available to facilitate CO2 uptake from the cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1996.tb00330.x
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of carbon supply on the circadian rhythmicity of photosynthesis and its stimulation by blue light in Ectocarpus siliculosus: clues to the mechanism of inorganic carbon acquisition in lower brown algae (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Stimulation or light-saturated rates of photosynthesis in Ectocarpus siliculosus (Dillwyn) Lyngb. by blue light was eliminated by increasing dissolved inorganic carbon (DIC) or by lowering pH in natural seawater. The amplitude of the circadian rhythm of photosynthesis was also diminished under these conditions, and the pH compensation points in a closed system were higher in the presence of blue light and during the circadian day. These observations suggest that blue light and the circadian clock regulate the activity of a carbon acquisition system in these plants. The inhibitor of external carbonic anhydrase, acetazolamide, reduced overall rates of photosynthesis by only about 30%, but ethoxyzolamide suppressed the circadian rhythm of photosynthesis almost completely and markedly reduced the duration of responses to blue light pulses. Similar patterns were obtained when photosynthesis was measured in strongly limiting DIC concentrations (0–0.5 mol m−3). Since blue light stimulated photosynthesis under these conditions of strong carbon limitation, we suggest that blue light activates the release of CO2 from an internal CO2 store. We propose a metabolic pathway with similarities to that of CAM plants. Non-photosynthetic fixation leads to the accumulation of a storage metabolite. The circadian clock and blue light control the mobilization of CO2 at the site of decarboxylation of this metabolite. In the presence of continuous blue light the pathway is proposed to cycle and act as a pump for CO2 into the chloroplasts. This hypothesis helps to explain a number of previously reported peculiarities of brown algal photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1996.tb00329.x
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  • 5
    Electronic Resource
    Electronic Resource
    Application of Vinyl Esters for the Lipase-catalyzed High-Yield Synthesis of Monoacylglycerols (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 799 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb33287.x
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  • 6
    Electronic Resource
    Electronic Resource
    (Acetonitrile-N)(η4-2-methylbuta-1,3-diene)(η5-pentamethylcyclopentadienyl)ruthenium(II) trifluoromethanesulfonate (1999)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 2053-2055 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270199012342
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  • 7
    Electronic Resource
    Electronic Resource
    Interaction of Bilirubin with Albumin (1965)
    [s.l.] : Nature Publishing Group
    Nature 206 (1965), S. 1041-1043 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] 'Sephadex' gel-filtration was used to separate albumin; bound bilirubin from unbound pigment; the bilirubin?albumin complex passed through the gel rapidly, while the smaller molecules of unbound pigment remained on the column. Therefore, the maximum binding capacity of the protein could be ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2061041b0
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  • 8
    Electronic Resource
    Electronic Resource
    Die Änderung der Elektronenstruktur des Nickels durch Wasserstoffbeladung (1966)
    Springer
    The European physical journal 190 (1966), S. 10-15 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract TheK-absorption spectrum of nickel charged with hydrogen has been investigated using a Bragg spectrograph with photographic registration. The fine structure of the absorption edge of the nickel hydride as compared with that of nickel shows that the electrons of the dissolved hydrogen fill up the empty 3d- and 4s-states of the conduction band of the metal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01340345
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  • 9
    Electronic Resource
    Electronic Resource
    Gutartiger Tumor des AV-Knotens (Mesotheliom) und plötzlicher Tod (1998)
    Springer
    Rechtsmedizin 8 (1998), S. 102-104 
    Details
    ISSN: 1434-5196
    Keywords: Key words Heart ; Conduction system ; Mesothelioma ; of av-node ; Schlüsselwörter Herz ; Erregungsleitungssystem ; Gutartiger Tumor ; Mesotheliom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Bericht über 2 Fälle mit einem gutartigen Tumor des AV-Knotens (sog. Mesotheliom). Im einen Fall dürfte der Tumor für eine langjährig bekannte Erregungsleitungsstörung (AV-Block) und für den plötzlichen Todeseintritt verantwortlich sein.
    Notes: Abstract A report on two cases with benign tumors of the atrioventricular node (so-called mesothelioma of the av-node or endodermal inclusions of the heart). In one of the cases the tumor could be the cause of the known electrophysiological disturbance of the conduction system (av-block) and of the sudden and unexpected death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001940050039
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  • 10
    Electronic Resource
    Electronic Resource
    The substitution chemistry of RuCp* (temeda)Cl (1997)
    Springer
    Monatshefte für Chemie 128 (1997), S. 1189-1199 
    Details
    ISSN: 1434-4475
    Keywords: Ruthenium half-sandwich complexes ; Tetramethylethylenediamine ; Ruthenacycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Chloridabspaltung von RuCp*(tmeda)Cl (1,tmeda=Me2NCH2CH2NMe2) mittels NaBPh4 in CH2Cl2 führt zur Bildung des Halbsandwich-Komplexes RuCp*(η6-C6H5BPh3) (2), während in Gegenwart von CH3CN oder CO die beiden kationischen Verbindungen [RuCp*(tmeda)(CH3CN)]+ (3) und [RuCp*(tmeda)(CO)]+ (5) entstehen. In CH3CN als Lösungsmittel wird sogartmeda unter Bildung von [RuCp*(CH3CN)3]+ (4) verdrängt. Komplex1 reagiert sehr leicht mit terminalen Alkinen HC≡CR, wobei die Produkte stark von der Natur des SubstituentenR (Ph, SiMe3,n-Bu, COOEt) abhängen. Im Fall vonR=Ph entsteht der Ruthenacyclopentatrien-Komplex RuCp*(σσ′-C4Ph2H2)Cl (6), mitR=SiMe3 der Cyclobutadien-Komplex Ru(Cp*)(η4-C4H2(1,2-SiMe3)2)Cl (7), und im Fall vonR=n-Bu und COOEt bilden sich die binuklearen Komplexe (Cp*)RuCl2(η2:η4-μ2-C4H2(1,3-R)2)Ru(Cp*) (8,9). Überdies reagiert1 mit Maleinsäurediethylester in Gegenwart von LiCl zum neuen anionischen Komplex Li[Ru(Cp*) (η2-C2H2(COOEt)2)Cl2] (10). Von2,3,4,7 und10 wurden die Kristallstrukturen bestimmt.
    Notes: Summary Halide abstraction from RuCp*(tmeda)Cl (1,tmeda=Me2NCH2CH2NMe2) with NaBPh4 in CH2Cl2 leads to the formation of the sandwich complex RuCp*(η6-C6H5BPh3) (2). In the presence of CH3CN (1 equiv.) and CO, however, the cationic complexes [RuCp*(tmeda)(CH3CN)]+ (3) and [RuCp*(temeda)(CO)]+ (5) are obtained. In CH3CN,tmeda is also replaced giving [RuCp*(CH3CN)3]+ (4). Complex1 reacts readily with terminal acetylenes HC≡CR, the products depending on the nature ofR (Ph, SiMe3,n-Bu, COOEt). Thus, withR=Ph the ruthenacyclopentatriene complex RuCp*(σ,σ′-C4Ph2H2)Cl (6), withR=SiMe3 the cyclobutadiene complex Ru(Cp*)(σ4-C4H2(1,2-SiMe3)2)Cl (7), and withR=n-Bu and COOEt the binuclear complexes (Cp*)RuCl2(η2:η4-μ2-C4H2(1,3-R)2)Ru(Cp*) (8,9) are obtained. Furthermore, with diethyl maleate in the presence of 1 equiv. of LiCl,1 transforms into the new anionic complex Li[Ru(Cp*) (η2-C2H2(COOEt)2)Cl2] (10). X-ray structures of2,3,4,7, and10 are included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807250
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