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  • 1990-1994  (9)
  • 1985-1989
  • 1980-1984
  • 1955-1959
  • 1993  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 3372-3374 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Barium titanate thin films were deposited on metallic conducting BaPbO3 ceramic substrates by the sol-gel method using metal alkoxides. The thin films with a thickness of around 0.4 μm were confirmed to have a perovskite structure and to be highly resistive with a resistivity of more than 1011 Ω cm at room temperature. The typical dielectric constant and dissipation factor of the films were 600 and less than 2% (1 kHz), respectively, at room temperature. From ferroelectric hysteresis measurements a remnant polarization of around 1.5 μC/cm2 and a coercive field of about 28 kV/cm were obtained for the films.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 5 (1993), S. 215-226 
    ISSN: 1435-1463
    Keywords: Monoamines ; amino acid ; purine metabolites ; cerebrospinal fluid ; aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied age-related changes in the concentrations of monoamines, amino acids, and their related substances in the cerebrospinal fluid on 144 neurologically normal subjects. The concentrations of tyrosine, 3-O-methyldopa, dopamine (total), norepinephrine (total), homovanillic acid, p-hydroxyphenylacetic acid, and 5-hydroxytryptophan increased significantly with age (p〈0.05), and the concentration of 3.4-dihydroxyphenylacetic acid displayed a non-significant trend to decrease, whereas concentrations of other monoamine precursors and metabolites were unchanged. We found the significant positive correlations between the concentrations of HVA and 5-HIAA (p〈0.001), between tyrosine and tryptophan (p〈0.001), and between tyrosine and 3-O-methyldopa (p〈0.001). The concentrations of asparagine, glycine, taurine, and alanine increased significantly with age (p〈0.05), while glutamine, arginine, and threonine concentrations did not change with age. The aspartate, glutamate, and GABA concentrations displayed the non-significant trends to decrease in the elderly subjects. The concentrations of aspartate, glutamate, and GABA had mutually significant positive correlations (p〈0.05), but had significant negative correlations with the concentrations of some neutral amino acids. The urate and xanthine concentrations increased significantly with age (p〈0.01). These findings suggest that the concentrations of monoamine and amino acid transmitters and their related compounds in the cerebrospinal fluid reflect age-related changes in the synthesis, release, and reuptake mechanisms of the transmitters and their transport mechanisms across the blood-brain barrier.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1463
    Keywords: L-threo-DOPS ; freezing of gait ; norepinephrine ; dopamine ; cerebrospinal fluid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the effects of L-threo-DOPS (L-DOPS) on the concentrations of total (conjugated and unconjugated) dopamine (DA) and norepinephrine (NE) in the cerebrospinal fluid (CSF) of parkinsonian patients with freezing phenomenon. The NE concentration increased remarkably and dose-dependently after administration of L-DOPS in both L-dopa/carbidopa-pretreated and untreated patients. The DA concentration also increased mildly but significantly in L-dopa/carbidopa-untreated patients. Freezing phenomenon improved in 6 out of 8 patients at Hoehn and Yahr's stage III, and 1 out of 5 patients at stage IV. These results indicate that L-DOPS administration increases the NE concentration dosedependently, and is effective for freezing of gait of moderate severity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1463
    Keywords: Parkinson's disease ; monoamines ; cerebrospinal fluid ; L-dopa ; freezing of gait
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We correlated monoamine concentrations in the cerebrospinal fluid from de novo (untreated) patients with Parkinson's disease with their clinical symptoms and therapeutic outcome after two years of L-dopa with/without other anti-parkinson medication. A significant correlation was found between the severity of some parkinsonian symptoms and the reduction in particular monoamines: Hoehn and Yahr's stage with dopamine, norepinephrine, and homovanillic acid: rigidity with dopamine; akinesia with dopamine and norepinephrine; freezing of gait with norepinephrine; and dementia with dopamine and homovanillic acid. Tremor had no correlations with the concentrations of the monoamines measured. Patients with dementia had a significantly increased level of epinephrine concentrations. Insufficient therapeutic responses of invidividual symptoms were associated with significantly decreased concentrations of particular monoamines before treatment: Hoehn and Yahr's stage with norepinephrine and epinephrine; akinesia with homovanillic acid and 5-hydroxyindoleacetic acid; and freezing of gait with dopamine, norepinephrine, homovanillic acid, and 5-hydroxyindoleacetic acid. These results suggest a significant correlation between the reduction in particular monoamines and the severity of some parkinsonian symptoms and their subsequent responses to L-dopa.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1435-1463
    Keywords: Urate ; xanthine ; vascular dementia of the Binswanger type ; Alzheimer type dementia ; Parkinson's disease ; cerebrospinal fluid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We determined the urate and xanthine concentrations in the cerebrospinal fluid (CSF) in patients with vascular dementia of the Binswanger type (VDBT), Alzheimer type dementia (ATD), and Parkinson's disease (PD). We found that the urate concentration was significantly increased in VDBT patients, but significantly decreased in ATD patients compared with controls. The ratio of the concentrations of uric acid (UCSF) to xanthine (XCSF) in the CSF (UCSF/XCSF) had a significant correlation with the ratio of the UCSF to the urate concentration in serum (Userum) (UCSF/Userum) in ATD and PD, whereas UCSF/Userum increased independently of UCSF/XCSF in VDBT. We concluded that the significant increase in the urate concentration in VDBT is mainly due to an impairment of the blood-brain barrier (BBB), and its significant reduction in ATD may reflect impaired brain metabolism.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1920
    Keywords: Menkes' syndrome ; Magnetic resonance imaging ; Magnetic resonance angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report two boys with Menkes' syndrome who underwent cranial MRI and MR angiography (MRA). In both, CT and MRI revealed progressive cerebral atrophy with a subdural haematoma or effusion. Delayed myelination or dysmyelination of the white matter was suggested. Tortuosity of the cervical and intracranial vessels was well demonstrated by MRA, obviating more invasive conventional angiography should it be thought necessary to demonstrate the characteristic systemic vascular changes of this syndrome.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inherited metabolic disease 16 (1993), S. 876-880 
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 45-53 
    ISSN: 1572-9567
    Keywords: density ; diethylene glycol ; ethylene glycol ; HFC-134a ; polyethylene glycol ; polypropylene glycol ; tetraethylene glycol ; triethylene glycol ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Liquid viscosity and density of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (400), and polypropylene glycol (2000)] have been measured in the temperature range from 273 to 333 K. The viscosity was measured by a rolling-ball viscometer calibrated with standard liquids of viscosities and densities (JS5, JS10, JS20, and JS50). The density was measured with a glass pycnometer. The uncertainties of the measurements were estimated to be less than 3.4 % for viscosity and 0.04 % for density, respectively. An equation is given to represent the obtained viscosity values as a function of weight fraction and temperature.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 339-342 
    ISSN: 1572-9567
    Keywords: density ; HCFC ; HCFC-141b ; HCFC-142b ; HCFC-225ca ; HCFC-225cb ; hydrochlorofluorocarbon ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Measurements of saturated liquid viscosities and densities were performed on environmentally acceptable hydrochlorofluorocarbons (HCFCs), CH3CCl2F (HCFC-141b), CH3CClF2 (HCFC-142b; only for viscosity), CF3CF2CHCl2 (HCFC-225ca), and CClF2CF2CHClF (HCFC-225cb), using a capillary viscometer and a glass pycnometer in the temperature range from 273 to 353 K. The uncertainty in the measurement of viscosity is estimated to be 5% based on the comparison of the present data with those in the literature for HCFC-141b. An equation is given to represent our saturated liquid viscosity data as a function of temperature.
    Type of Medium: Electronic Resource
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