Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  In the discussion of possible toxic effects of carbon particle emissions from automotive sources the question about the origin of the material is of relevance. Besides the emissions of Diesel soot (DS) a second source of debris from tire abrasion (TD) has the potential to contribute significantly to the carbon particle emissions. The discrimination between these chemically different species is complicated by the unavoidable presence of molecular carbon species from general sources, from fuel components and from polycyclic aromatic hydrocarbons (PAH) on the filter surface deposits from imission tests. Based on the different surface reactivity of DS and TD, a quantitative data analysis procedure using the X-ray photoelectron spectroscopy (XPS) carbon 1s profile is suggested, which gives an estimate of the fraction of DS in the total carbon present. The difference to 100% is the sum of TD and molecular carbon which constitutes its dominant contribution. The method agrees semi-quantitatively with traditional chemical analysis of the elemental carbon fraction on the filters. Several independent chemical tests are provided for the internal consistency of the analysis method which is based upon the use of reference spectra from pure TD. The application of a simplified analytical equipment for large numbers of samples is discussed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The subfornical organ, median preoptic nucleus and the organum vasculosum of the lamina terminalis (OVLT) are a series of structures situated in the anterior wall of the third ventricle and form the lamina terminalis. The OVLT and ventral part of the median preoptic nucleus are part of a region known as the anteroventral third ventricle region.2. Data from many laboratories, using techniques ranging from lesions, electrophysiology, neuropharmacology, Fos expression, immunohistochemistry and receptor localization, indicate that the tissue in the lamina terminalis plays a major role in many aspects of body fluid and electrolyte balance.3. The subfornical organ and OVLT lack the blood-brain barrier and detect alterations in plasma tonicity and the concentrations of circulating hormones such as angiotensin II and possibly atrial natriuretic peptide and relaxin.4. This information is then integrated within the lamina terminalis (probably in the median preoptic nucleus) with neural signals from other brain regions. The neural output from the lamina terminalis is distributed to a number of effector sites including the paraventricular (both parvo- and magno-cellular parts) and supraoptic nuclei and influences vasopressin secretion, water drinking, salt intake, renin secretion, renal sodium excretion and cardiovascular regulation.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 〈list xml:id="l1" style="custom"〉1Autoradiographic binding studies have shown that the AT1 receptor is the predominant angiotensin II (AngII) receptor subtype in the central nervous system (CNS). Major sites of AT1 receptors are the lamina terminalis, hypothalamic paraventricular nucleus, the lateral parabrachial nucleus, rostral and caudal ventrolateral medulla, nucleus of the solitary tract and the intermediolateral cell column of the thoraco-lumbar spinal cord.2While there are differences between species, AT2 receptors are found mainly in the cerebellum, inferior olive and locus coeruleus of the rat.3Circulating AngII acts on AT1 receptors in the subfornical organ and organum vasculosum of the lamina terminalis (OVLT) to stimulate neurons that may have a role in initiating water drinking.4Centrally administered AngII may act on AT1 receptors in the median preoptic nucleus and elsewhere to induce drinking, sodium appetite, a sympathetic vasoconstrictor response and vasopressin secretion.5Recent evidence shows that centrally administered AT1 antagonists inhibit dipsogenic, natriuretic, pressor and vasopressin secretory responses to intracerebroventricular infusion of hypertonic saline. This suggests that an angiotensinergic neural pathway has a role in osmoregulatory responses.6Central angiotensinergic pathways which include neural inputs to the rostral ventrolateral medulla may use AT1 receptors and play a role in the function of sympathetic pathways maintaining arterial pressure.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoconducting model systems: poly(N-vinylcarbazole)/polycarbonate (PVK/PC) blends were investigated by simultaneous measurements of thermally stimulated currents (TSC) and thermoluminescence (TL). It was found that with increasing applied electric field, the TSC maximum increases and shifts towards lower temperatures, but the TL maximum decreases and its position on temperature scale remains unchanged. Moreover, the TSC maximum shifts also towards lower temperatures with increasing PVK content and with decreasing sample thickness and its position depends on the applied electric field polarity in a case when the sample is excited at low temperatures with a strongly absorbed light. The position of the TL maximum is unaffected by these factors. It is concluded that the field dependent TSC maximum cannot be interpreted in terms of the Poole-Frenkel effect, but it is the so-called "transport peak,'' determined by transport and trapping phenomena, and can be regarded as thermally stimulated time-of-flight signal. Spectral analysis of TL indicates that it is characteristic of PVK phosphorescence. It results from recombination of charge carriers thermally liberated from neutral traps under the influence of a charged recombination center, and it can be described by a model based on the Onsager theory of geminate recombination. The detrapping is probably stimulated by the so called "wet dog'' effect, related to molecular γ-relaxation in PVK. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Allergy 54 (1999), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1365-2516
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1476-5535
    Keywords: Saccharomyces sensu stricto ; sibling species ; genetic taxonomy ; yeast cultivars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Studies on taxonomic and evolutionary genetics of theSaccharomyces sensu stricto complex are considered in light of the biological species concept. Genetic variability of some physiological properties traditionally used in yeast taxonomy is discussed. Genetic hybridization analysis and molecular karyotyping revealed six biological species in theSaccharomyces sensu stricto complex. DNA-DNA reassociation data are concordant with the data obtained by genetic analysis. A new system for naming the cultivatedSaccharomyces yeast (groups of cultivars) is proposed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...