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  • 1
    Electronic Resource
    Electronic Resource
    Preparation and Properties of Imido Intermediates (Imidogens) (1964)
    s.l. : American Chemical Society
    Chemical reviews 64 (1964), S. 149-185 
    Details
    ISSN: 1520-6890
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cr60228a005
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  • 2
    Electronic Resource
    Electronic Resource
    Deuterium isotope effects in the ninhydrin reaction of primary amines (1982)
    Springer
    Cellular and molecular life sciences 38 (1982), S. 299-300 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rate of development of Ruhemann's purple in the ninhydrin reaction of two deuterated primary amines, αα-d2-p-tyramine and αα-d2-β-phenylethylamine, is significantly reduced It appears to be a primary isotope effect and indicates that the cleavage of the carbon-hydrogen bond at the α-position is involved in the rate-determining step of the color reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01949352
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  • 3
    Electronic Resource
    Electronic Resource
    Photoconductor x/γ-ray detectors and x-ray bolometers (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2182-2183 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Photoconductors are very promising x/γ-ray detectors and x-ray bolometers for pulsed x/γ-ray measurements. They are fast, sensitive, and theoretically flat in spectral response for low energy x rays. We report our tests of InP:Fe, GaAs, and GaAs:Cr, both neutron damaged and undamaged, at Nova laser, Febetrons, and electron linear accelerators. The temporal and spectral responses are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138724
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  • 4
    Electronic Resource
    Electronic Resource
    Neutron-treated, ultrafast, photoconductor detectors (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1451-1453 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated homogeneous, photoconductive semiconductors as very fast radiation detectors. We irradiated GaAs, Cr-doped GaAs, and Fe-doped InP crystals with 14 MeV neutrons to produce lattice defects that act as fast recombination centers for electrons and holes. Using short-pulse lasers and 17 MeV linear-accelerator electrons and bremsstrahlung x rays, we measured the temporal response and sensitivity of these photoconductors as functions of fluence ranging from 1012 to 1016 neutrons/cm2. The carrier lifetime and mobility decrease monotonically as the neutron fluence increases, resulting in faster detector response at the expense of sensitivity. A resolving time of less than 30 ps (full width at half maximum) was measured for the above photoconductors irradiated with ∼1015 neutrons/cm2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100694
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  • 5
    Electronic Resource
    Electronic Resource
    Neuroprotective Effects of Some Monoamine Oxidase-B Inhibitors Against DSP-4-Induced Noradrenaline Depletion in the Mouse Hippocampus (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 63 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], a selective noradrenaline (NA) uptake blocker, is capable of inducing long-lasting depletion of NA in some noradrenergic axon terminals and of subsequently causing cell death to NA neuronal cell bodies in rodents. R(−)-Deprenyl, a selective monoamine oxidase (MAO)-B inhibitor, has been shown to be capable of protecting animals against this DSP-4-induced neuronal degeneration. Its action, however, has been claimed to be unrelated to the inhibition of MAO-B activity but rather due to competition for the NA uptake sites. The effects of several types of MAO inhibitors against DSP-4 toxicity, MAO-B activity both in vivo and in vitro, and NA uptake into the hippocampus have been assessed. N-(2-Hexyl)-N-methylpropargylamine (2-HxMP), a potent MAO-B inhibitor, for example, exerts no appreciable effect on NA uptake but is quite potent in counteracting the NA-depleting effect of DSP-4. Such results rule out the possibility that the neuroprotective effect of the MAO-B inhibitors is due mainly to their effect on NA uptake. The in vitro inhibition of MAO-B activity seems to correlate positively with their neuroprotective effects against DSP-4. In comparison to the MAO-B inhibitors, NA uptake blockers, such as desipramine and S(+)-deprenyl, exhibit relatively low efficacy in protecting the NA axon terminals from the effects of DSP-4-induced damage. The restoration of hippocampal NA levels is significantly enhanced with repeated treatments of R(−)-deprenyl or 2-HxMP even at very low doses following the DSP-4 insult. This suggests that in addition to neuroprotection, these MAO-B inhibitors may rescue some of the noradrenergic axon terminals damaged by DSP-4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.63051820.x
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  • 6
    Electronic Resource
    Electronic Resource
    Neurochemical and Neuroprotective Effects of Some Aliphatic Propargylamines: New Selective Nonamphetamine-Like Monoamine Oxidase B Inhibitors (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Aliphatic N-propargylamines have recently been discovered to be highly potent, selective, and irreversible monoamine oxidase B (MAO-B) inhibitors. N-Methyl-N-(2-pentyl)propargylamine (M-2-PP) and N-methyl-N-(2-hexyl) propargylamine (2-HxMP), for example, are approximately fivefold more potent than I-deprenyl at inhibiting mouse brain MAO-B activity following oral administration. These inhibitors are nonaromatic compounds and are chemically quite different from other known MAO-B inhibitors. Some of their neurochemical and neuroprotective properties have been evaluated and compared with those of I-deprenyl. We have confirmed that these new inhibitors selectively inhibit MAO-B activity both in vitro and in vivo. 2-Phenylethylamine levels were substantially increased following administration of M-2-PP, but the levels of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 5-hydroxytryptamine, and 5-hydroxyindoleacetic acid were not affected except at high, nonselective doses. Chronic oral administration of I-deprenyl and M-2-PP causes selective inhibition of MAO-B activity and increases dopamine levels in mouse caudate. M-2-PP, like I-deprenyl, has been shown to be potent in protecting against MPTP-induced damage in the mouse. N-(2-Chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4), a noradrenaline neurotoxin, is not an MAO substrate. Its noradrenaline-depleting effects were substantially mitigated by I-deprenyl as well as by M-2-PP and 2-HxMP in the mouse hippocampus. Administration of 2-phenylethylamine, however, failed to reverse the effect of DSP-4. The neuroprotective effect of M-2-PP and 2-HxMP is apparently unrelated to the uptake of DSP-4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62020697.x
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  • 7
    Electronic Resource
    Electronic Resource
    Deuterium Isotope Effect in γ-Aminobutyric Acid Transamination: Determination of Rate-Limiting Step (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 48 (1987), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The rate of transamination of γ-aminobutyric acid (GABA) catalyzed by hog brain γ-aminobutyrate ami-notransferase was substantially reduced when the hydrogen at the γ-carbon position was replaced by deuterium. The deuterium isotope effect of this reaction has been substantiated by fluorometric, radiometric, and mass spectrometric procedures and assessed kinetically. The ratios of Vmax of the nonlabeled substrate/Vmax of the deuterated substrate obtained under different conditions ranged from 6 to 7. This indicates that the cleavage of the hydrogen from the γ-carbon is the rate-determining step in GABA transamination. Similar isotope effects have also been shown to occur in the peripheral system in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1987.tb04112.x
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  • 8
    Electronic Resource
    Electronic Resource
    A solid dielectric Compton diode for measuring short radiation pulse widths (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3447-3451 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple, rugged, and inexpensive solid dielectric Compton diode (SCD) has been developed for measuring the radiation-time history of flash x-ray sources. By limiting the physical size of the Compton diode and matching its characteristic impedance to that of the signal cable, a frequency response above 1 GHz has been achieved. The SCD has been used to measure the pulse width and rise time of HERMES III, a pulsed γ-ray simulator. A second, prototype SCD has been built for use with Saturn, a pulsed x-ray simulator. The SCDs do not have high sensitivity, and are thus limited to measurements of dose rate above 109 rads/s, due to signal-to-noise limitations. At lower dose rates, more sensitive detectors such as scintillator photodiodes or p-i-n diodes are more suitable. On the other hand, for dose rates above 1010 rads/s, the more sensitive detectors tend to saturate, while the SCD continues to respond linearly to at least 1012 rads/s. Thus, the SCD is well suited for measuring radiation-time histories at high dose rates on flash x-ray sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141600
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  • 9
    Electronic Resource
    Electronic Resource
    Collagenase and Tissue Plasminogen Activator Production in Developing Rat Calvariae: Normal Progression Despite Fetal Exposure to Microgravity (1998)
    Springer
    Calcified tissue international 63 (1998), S. 416-422 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Collagenase — Tissue plasminogen activator — Spaceflight — Osteoblast — Zero gravity.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Exposure to zero gravity has been shown to cause a decrease in bone formation. This implicates osteoblasts as the gravity-sensing cell in bone. Osteoblasts also are known to produce neutral proteinases, including collagenase and tissue plasminogen activator (tPA), which are thought to be important in bone development and remodeling. The present study investigated the effects of zero gravity on development of calvariae and their expression of collagenase and tPA. After in utero exposure to zero gravity for 9 days on the NASA STS-70 space shuttle mission, the calvariae of rat pups were examined by immunohistochemistry for the presence and location of these two proteinases. The ages of the pups were from gestational day 20 (G20) to postnatal (PN) day 35. Both collagenase and tPA were found to be present at all ages examined, with the greatest amount of both proteinases present in the PN14 rats. At later ages, high amounts were maintained for tPA but collagenase decreased substantially between ages PN21 to PN35. The location of collagenase was found to be associated with bone-lining cells, osteoblasts, osteocytes, and in the matrix along cement lines. In contrast, tPA was associated with endothelial cells lining the blood vessels entering bone. The presence and developmental expression of these two proteinases appeared to be unaffected by the exposure to zero gravity. The calvarial thickness of the pups was also examined; again the exposure to zero gravity showed little to no effect on the growth of the calvariae. Notably, from G20 to PN14, calvarial thickness increased dramatically, reaching a plateau after this age. It was apparent that elevated collagenase expression correlated with rapid bone growth in the period from G20 to PN14. To conclude, collagenase and tPA are present during the development of rat calvariae. Despite being produced by the same cell in vitro, i.e., the osteoblast, they are located in distinctly different places in bone in vivo. Their presence, developmental expression, and quantity do not seem to be affected by a brief exposure to zero gravity in utero.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900550
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  • 10
    Electronic Resource
    Electronic Resource
    The effect ofl-deprenyl on behavior, cognitive function, and biogenic amines in the dog (1993)
    Springer
    Neurochemical research 18 (1993), S. 1211-1219 
    Details
    ISSN: 1573-6903
    Keywords: l-Deprenyl ; monoamine oxidase ; dopamine ; cognitive function ; dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Behavioral and pharmacological effects of oral administration ofl-deprenyl in the dog are described. Spontaneous behavior is unaffected at doses below 3 mg/kg while at higher doses there was stereotypical responding. There was evidence of improved cognitive function in animals chronically treated with a 1 mg/kg dose but the effectiveness varied considerably between subjects. Chronic administration produced a dose dependent inhibition in brain, kidney and liver monoamine oxidase B, and had no effect on monoamine oxidase A. There were also dose dependent increases in brain phenylethylamine and in plasma levels of amphetamine. Dog platelets did not have significant levels of MAO-B. Brain dopamine and serotonin metabolism were unaffected byl-deprenyl at doses up to 1 mg/kg. It appears that for the dog, deamination of catecholamines is controlled by MAO-A. Nevertheless, it is suggested thatl-deprenyl serves as a dopaminergic agonist, and there is also evidence that it affects adrenergic transmission. These catecholaminergic actions may account for the effects ofl-deprenyl on behavior and cognitive function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00975038
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