Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (6)
  • 1955-1959
  • 1920-1924
  • Analytical Chemistry and Spectroscopy  (3)
  • Memory  (2)
  • 1H-NMR imaging  (1)
  • 1
    ISSN: 1432-2072
    Keywords: Benzodiazepines ; Diazepam ; Human ; Lorazepam ; Memory ; Repetition priming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of two benzodiazepines, diazepam (15 or 20 mg orally) and lorazepam (1.75 or 2.5 mg orally), and a placebo on explicit memory, lexical priming and perceptual priming were assessed using a freerecall, a word-completion and a picture-completion test. The picture-completion test included two different study conditions intended to manipulate the magnitude of the priming effect. Sixty healthy volunteers took part in this double-blind study. Free-recall performances were altered by both drugs. Lorazepam impaired word-completion and picture-completion performance, whereas diazepam only exhibited a deleterious effect on the more sensitive of the two measures of the picture-completion test. These results indicate that the two benzodiazepines have differential amnestic effects. It is suggested that these differential effects could be accounted for by a different cortical distribution of the two benzodiazepines.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-2072
    Keywords: Benzodiazepine ; Diazepam ; Human ; Lorazepam ; Memory ; Perceptual priming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Unlike diazepam, lorazepam has repeatedly been shown to impair perceptual priming as well as explicit memory. To determine whether this deleterious effect was due to an impairment in acquisition of information, 60 healthy volunteers were randomly assigned to five treatment groups (placebo, lorazepam 0.026 or 0.038 mg/kg, diazepam 0.2 or 0.3 mg/kg) and successively performed perceptual priming tasks and a free-recall task. Priming performance on information learned before or 2 h after drug administration, i.e. at the peak concentration of lorazepam, was assessed under the influence of the drugs, using a picture-fragment and a word-stem completion task. Free-recall performance was altered by both drugs. Lorazepam decreased priming performance when information was acquired after, but not before, drug administration, indicating that the drug alters the acquisition of information. Lorazepam also impaired the ability to identify fragmented pictures, but there was no evidence that this perceptual effect accounts for the priming impairment. Surprisingly, diazepam also decreased priming when information was acquired after drug administration, suggesting that, at least in certain circumstances, the two benzodiazepines may exert similar effects on priming measures.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-6792
    Keywords: 1H-NMR imaging ; (Rat) brain ; Fimbria fornix ; Hippocampus ; Ventricle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mechanical lesions of the fimbria fornix (FF) have been widely used as a model to investigate the recovery of damaged brain tissue.1H-NMR imaging was employed to non-invasively measure changes in the brain after unilateral FF transection. Rats were subjected to NMR imaging at various times after the lesions were made. The experimental protocol included (multislice) T2-weighted and diffusion-weighted imaging thereby allowing the construction of two-dimensional maps of the relaxation time T2 (transverse or spin-spin relaxation time) and the apparent diffusion coefficient (ADC) of water. FF transection induced considerable changes in the status of the brain tissue at a number of different locations which were exclusively present in the affected hemisphere. At 1 day post-lesion the region of the lateral ventricle and hippocampus started to display pronounced changes in that T2- and diffusion-weighted images showed a hyperintensity and a hypointensity, respectively. These effects were maximal around day 2 to 4 whereafter a slow recovery towards the control situation was observed. Immediately after transection the FF lesion itself could be visualized. These early images pointed to an aspecific disruption of the tissue due to the mechanical intervention. Interestingly, however, from day 2 post-lesion a number of changes became evident in this region which seemed to be localized to specific structures, including the ventricle and hippocampus. After one month the presumably ventricular effect dominated and was predominantly localized to the anterior side of the FF lesion. These findings are indicative of pronounced changes in the status of water (e.g., in its distribution between extra- and intracellular compartments) at a number of locations distant from the site of FF transection. The mechanism by which these changes are brought about and the origin of their time-dependence remain to be elucidated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 692-694 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Electrospray mass spectrometry has been applied to ionic inorganic systems such as heteropolyacids in methanol + water (1/1) or acetonitrile + water (1/1) solutions. Negative-ion mass spectra were obtained on four different heteropolyacids. Heteropolymolybdates H3PMo12O40 and H4PMo11VO40 and heteropolytungstates H3PW12O40 and H4SiW12O40 gave ions with different charges. H3PMo12O40 gave ions of m/z 1822, 912 and 608 which correspond respectively to [PMo12O403- + 2H+], [PMo12O403- + H+]2- and [PMo12O40]3- ions. Resolution of 1:2200 has demonstrated the charge of each ion acquired. Furthermore, the isotope distribution of the observed ions was in good agreement with theory. Thus, electrospray mass spectrometry has become a powerful soft ionization technique for the analysis of such ionic compounds, provided they are soluble and stable in the solvent system used.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Until the present, analysis of aqueous solutions of atrazine has been conducted using a combination of liquid chromatography or gas chromatography with mass spectrometry, after a preconcentration step. We explore herein a new approach for studying support-phase-extracted atrazine and hydroxyatrazine samples. Solid-phase extraction membranes are inserted directly into the cell of a Fourier-transform mass spectrometer for analysis after laser ionization. It appears that atrazine and its metabolite have very different ionization processes. In the case of hydroxyatrazine, the [M + H]+ ion signal can be correlated to the concentration of the extracted solution. These encouraging results might open the route to a quantification method.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0749-1581
    Keywords: 27 Al MAS NMR ; Quadruopolar interaction parameters ; Isotropic chemical shfits ; Spectral simulation ; Al2Ge2O7 ; LaAlGe2O7 ; Pentacoordinated aluminium environment ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Characterization by 27Al MAS NMR of two pentacoordinated environments of aluminium has been carried out in different fields and at different spinning speeds for Al2Ge2O7 and LaAlGe2O7. Complete simulations of the spectra have been performed, including computation of the individual shape and intensity of each spinning side band, which lead to the determination of both the quadrupolar interaction parameters and isotropic chemical shifts, and enable the detection of impurities in the material. The parameters determined are: .
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...