Search Results - (Author, Cooperation:T. Clements)

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  1. 1
    T. Clements ; A. Dolocan ; P. Martin ; M. A. Purnell ; J. Vinther ; S. E. Gabbott
    Nature Publishing Group (NPG)
    Published 2016
    Staff View
    Publication Date:
    2016-04-14
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Animals ; *Eye/chemistry/cytology/ultrastructure ; *Fossils ; Illinois ; Melanosomes/ultrastructure ; Microscopy, Electron, Scanning ; *Phylogeny ; Retinal Pigment Epithelium/chemistry/ultrastructure ; Vertebrates/anatomy & histology/*classification
    Published by:
    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Sloan, J. W. ; Martin, W. R. ; Clements, T. H. ; Buchwald, W. F. ; Bridges, S. R.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1975
    Staff View
    ISSN:
    1471-4159
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    With a modification of the spectrophotofluorometric (SPF) method of HESS & UDENFRIEND (1959) (J. Pharmac. exp. Ther.127, 175-177), brain tryptamine levels in the rat (20.9 ng/g) and guinea-pig (20.7 ng/g) were found to be less than those in the dog (32.1 ng/g) and cat (52.2 ng/g). Regional distribution studies in the dog and cat showed that tryptamine was present in all major brain regions with highest concentrations in the spinal cord. Blood levels of tryptamine in the guinea-pig, dog and cat (6-7 ng/ml) were lower than brain levels. Pargyline significantly increased brain tryptamine in both the dog and cat; whereas, isocarboxazid (after 4 h) increased brain tryptamine levels in the dog but decreased brain levels in the cat. Reserpine (0.5-1.0 mg/kg per day for 1-4 days) did not significantly decrease brain, spinal cord or blood tryptamine levels in the dog. Spinal cord transection did not decrease tryptamine levels below the lesion in the chronic spinal dog.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  3. 3
    Hanold, K. A. ; Luong, A. K. ; Clements, T. G. ; Continetti, R. E.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    A new photoelectron–photofragment-coincidence spectrometer is described. Using a multiparticle time- and position-sensitive detector, this apparatus allows the study of dissociation processes of negative ions yielding three photofragments in coincidence with a photoelectron. The photoelectron spectrometer uses two detectors and works in time of flight mode, detecting 10% of the photoelectrons with an energy resolution of 5% at 1.3 eV as shown in studies of the photodetachment of O2−. A third detector is used for collection of multiple photofragments (up to 8) in coincidence. This multiparticle detector uses a crossed-delay-line anode and fast timing signals to encode the time- and position-of-arrival of multiple photofragments. The detector was demonstrated to record all three particles produced in a single three-body dissociation event, yielding an energy resolution of (approximate)15% ΔE/E at 0.7 eV in experiments on the three-body dissociative photodetachment of O6−. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  4. 4
    Luong, A. K. ; Clements, T. G. ; Sowa Resat, M. ; Continetti, R. E.

    College Park, Md. : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    The dissociative photodetachment of O2−(H2O)n=1–6 was studied at 388 and 258 nm using photoelectron–multiple-photofragment coincidence spectroscopy. Photoelectron spectra for the series indicate a significant change in the energetics of sequential solvation beyond the fourth water of hydration. Photoelectron–photofragment kinetic energy correlation spectra were also obtained for O2−(H2O)1–2, permitting a determination of the first and second energies of hydration for O2− to be 0.85±0.05 and 0.70±0.05 eV, respectively. The correlation spectra show that the peak photofragment kinetic energy release in the dissociative photodetachment of O2−(H2O) and O2−(H2O)2 are 0.12 and 0.25 eV, respectively, independent of the photon and photoelectron kinetic energies. The molecular frame differential cross section for the three-body dissociative photodetachment: O2−(H2O)2+hν→O2+2H2O+e− is also reported. The observed partitioning of momentum is consistent with either a sequential dissociation or dissociation from a range of initial geometries. © 2001 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    1432-2072
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Summary The effects of morphine (8 mg and 16 mg/70 kg) and pentobarbital (200 mg/70 kg) upon acquisition of a conditioned electrodermal response were studied. Both morphine (16 mg) and pentobarbital tended to reduce the degree of conditioning. In addition, morphine (16 mg) attenuated the increase in basal conductance relative to that which occurred under placebo during the conditioning period and did so more effectively than pentobarbital. Pentobarbital, but not morphine, decreased basal conductance under the non-shock condition. Morphine thus acted selectively on the effects of shock on basal conductance, and thereby, possibly, on anxiety. Neither morphine nor pentobarbital appeared to impair responsivity of the phasic EDR. The tentative hypothesis was offered that the tonic and phasic reactions of the electrodermogram are separately mediated and that morphine has a greater effect upon the neural basis for the tonic than for the phasic reaction.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  6. 6
    Staff View
    ISSN:
    1432-2072
    Keywords:
    Tryptamine ; Hallucinations ; Schizophrenia ; Serotonin ; Melatonin
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract A modification of the method of Hess and Udenfriend (1959) for the extraction and identification of tryptamine, as well as a gas chromatographic method for identifying tryptamine, has been described. Tryptamine, using these methods, as well as thin layer chromatography, has been identified in steer, dog and human brain. Tryptamine was not found in the rat brain. In the dog, isocarboxazid increased brain and spinal cord tryptamine levels two or three times. In view of the fact that tryptamine resembles LSD-like hallucinogens in many of its actions, it is suggested that tryptamine may be a naturally occurring hallucinogen that may play a role both in normal and pathologic functioning of the brain.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  7. 7
    Staff View
    ISSN:
    1432-2072
    Keywords:
    Tryptamine ; Spinal Cord ; Facilitation ; Neurotransmitters
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract The brain and spinal cord of the chronic spinal dog contained higher levels of tryptamine than comparable regions of the intact dog. The most significant brain elevations were found in the cerebellum and mesencephalon. Further, tryptamine in the white matter of the spinal cord above the level of transection was higher than below. These findings have been interpreted as indicating that there are tryptaminergic pathways descending in the white matter of the spinal cord from the mesencephalon, cerebellum and rostral spinal cord. The level of tryptamine below the transection was not different from that found in the intact dog, suggesting that there are not only descending but ascending tryptaminergic pathways and that when the axons are transected, tryptamine accumulates proximal to the level of transection.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses