Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 69 (1994), S. 59-64 
    ISSN: 1432-0738
    Schlagwort(e): Key words Tetraethoxysilane ; Semiconductor ; Time course study ; Renal toxicity ; Blood silicon concentration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  To clarify the time course of toxicological effects of tetraethoxysilane [Si(OC2H5)4, TEOS] on the kidney and the relationship between blood silicon levels (Si-B) and the effects, 250 mg/kg or 500 mg/kg TEOS was intraperitoneally administered to ten 5-week-old male ICR mice (SPF grade) in each group, and morphological and functional changes of the kidney were assessed at 12 h, 24 h, 3 days and 2 weeks after administration of TEOS. Injury to tubular epithelial cells was observed in mice killed 12 and 24 h after administration, and its severity increased with increasing dosage. The mean values of blood urea nitrogen exhibited dose-related increase in mice sacrificed 24 h after the administration. The concentrations of Si-B increased in order of the administered doses of TEOS, and then decreased steadily. The results of Si-B were consistent with the concept that renal toxicity of TEOS is mediated by siliceous compounds. The kidney was recovering from injury 3 days after administration, and had developed tubulointerstitial nephritis, which could be regarded as repaired lesion of acute injury, by 2 weeks after administration.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1432-0738
    Schlagwort(e): Key words Dichlorosilane ; Semiconductor ; Inhalation toxicity ; Respiratory tract ; Squamous metaplasia ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Using male ICR mice, the LC50 and acute and subacute inhalation toxicity of dichlorosilane (SiH2Cl2, DCS) and the fate of DCS released into the air were investigated. DCS resolved and minute particles including silicon and chloride were observed, when DCS was released into the air. Most particles were under 1 micron in diameter. The LC50 of DCS at 4-h exposure was 144 ppm (nominal concentration). In the acute inhalation study, ten mice in each group were exposed to 64 ppm (nominal concentration) DCS for 1, 2, 4 or 8 h. Body weight loss, wheezing and piloerection were observed in mice exposed for 2 h or more. Histopathologically, injury to the nasal mucosa and trachea were observed in all exposed mice. Mice exposed to 32 ppm (nominal concentration) DCS for 2 or 4 weeks also exhibited depression of body weight gain, wheezing and piloerection. Squamous metaplasia of the nasal mucosa and tracheal epithelium was observed in both 2- and 4-week exposure groups. Exposure to DCS was irritant or corrosive to the respiratory tract with both acute and subacute inhalation. Apart from silane (SiH4), toxic effects of DCS seem to be characterized by chloride compounds derived from DCS.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 36 (1989), S. 67-70 
    ISSN: 1432-1041
    Schlagwort(e): diltiazem ; propranolol ; metoprolol ; atenolol ; pharmacokinetics ; drug interaction ; beta-adrenoceptor blockade ; healthy volunteers ; pharmacodynamic effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetic interaction between diltiazem and three β-adrenoceptor blockers propranolol, metoprolol and atenolol was investigated in healthy volunteers given diltiazem 30 mg or placebo t.d.s. for 3 days, followed by a single dose of propranolol 20 mg, metoprolol 40 mg or atenolol 50 mg. The AUCs of propranolol and metoprolol were significantly increased after diltiazem and it significantly prolonged the elimination half-life of metoprolol. In contrast, it did not significantly affect the pharmacokinetics of atenolol. Propranolol significantly decreased the resting pulse rate after diltiazem pretreatment as compared to placebo. The results indicate that diltiazem impaired the clearance of propranolol and metoprolol, which are principally metabolized by an oxidative pathway, and that the kinetic interaction between diltiazem and propranolol may partly be related to the significant reduction in the pulse rate produced by the latter.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of fusion energy 3 (1983), S. 173-184 
    ISSN: 1572-9591
    Schlagwort(e): moving ring reactor ; tritium breeding ratio ; blanket ; heating rate ; first wall ; Monte Carlo calculation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Monte Carlo calculations on the tritium breeding ratio in the blanket and the heating rate in the first wall were carried out for moving ring reactor, KARIN-1. The blanket adopted in this calculation consists of a 2-cm thick silicon carbide (SiC) first wall, a 25-cm thick lithium (Li) layer, and a 10-cm thick lithium oxide (Li2O) layer. It was found that the tritium breeding ratio in the blanket and the heating rate in the first wall are changing cyclically with a 1 s period. The maximum tritium breeding ratio obtained is 1.12, the minimum is 1.01, and the average value over a 1 s period is 1.10. As for the heating rate at the center of the burning section, the maximum is ∼26 W/cc, the minimum ∼10 W/cc, the average ∼ 15 W/cc, and the ratio of the maximum to the minimum is ∼2.6. The corresponding values at the entrance of the burning section are ∼24 W/cc, ∼4 W/cc, ∼12 W/cc, and ∼6.7, respectively. These results provide the basic information for thermal and mechanical design of the reactor system.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of fusion energy 4 (1985), S. 315-319 
    ISSN: 1572-9591
    Schlagwort(e): optimization ; SENRI ; blanket ; tritium ; breeding ; energy multiplication ; molten salt ; nonbreeding ; hybrid ; support ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Neutronic calculations were performed to optimize the SENRI blanket in terms of energy multiplication as well as tritium breeding ratio. The blanket employs a thick (∼ 64-cm) Li layer as breeder/coolant. Three approaches were taken here to achieve the goal: (1) reduction of6Li in the lithium, (ii) replacement of the Li layer by a molten-salt (flibe) layer, and (iii) shipment of excess tritium to a nonbreeding blanket. It was found that the excess tritium produced in the SENRI blanket could be used effectively to obtain additional power by fueling a nonbreeding D-T reactor.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of fusion energy 4 (1985), S. 45-55 
    ISSN: 1572-9591
    Schlagwort(e): heliotron-H ; blanket ; shield ; superconducting magnet ; tritium breeding ratio ; atomic displacement ; dose rate ; shutdown ; Monte Carlo calculation ; THIDA code system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Nuclear analysis was carried out for the heliotron-H fusion power reactor employing anl=2 helical heliotron field. The neutronics aspects examined were (a) tritium breeding capability, (b) shielding effectiveness for the superconducting magnet (SCM), and (c) induced activity after shutdown. In this reactor design of the heliotron-H, the space available for the blanket and shield is limited due to the reactor geometry. Thus, some parametric survey calculations were performed to satisfy the design requirements. The nucleonic design features of the heliotron-H are as follows. An adequate tritium breeding ratio of 1.17 is obtained when a 10-cm thick Pb neutron multiplier and a 40-cm thick Li2O breeding blanket are used. In this case, the total nuclear energy deposition is 16.10 MeV per 14.06 MeV incident neutron. The performance of the SCM is assured during ∼2 yr of continuous operation using a 20-cm thick tungsten shield. Biological dose rate behind the SCM at 1 day after shutdown is too high for hands-on maintenance.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 133-137 
    ISSN: 1432-1041
    Schlagwort(e): propranolol ; chronopharmacology ; exercise-induced tachycardia ; pharmacokinetics ; healthy volunteers ; gastio-intestinal absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Following a cross-over design propranolol 20 mg p.o. was given to 7 healthy subjects at 09.00 h and 21.00 h at an interval of 1 week. Heart rate (HR) during submaximal ergometer exercise was measured at four intervals during 10 h after treatment. Plasma propranolol concentrations were also determined. The suppressive effect (%R) of propranolol on the rise in HR during exercise after the morning dosage was significantly greater at 1.5 h and tended to be greater 3 h after administration than at comparable times in the evening trial. Mean plasma propranolol concentrations during the early phase were higher after the morning than the evening dose. The maximum plasma concentration (Cmax), area under the plasma concentration-time curve from 0 to 10 h (AUC (0–10)) and absorption rate constant (ka) were significantly greater after the morning dose. The time to maximum concentration (tmax) and elimination half-life (t1/2) of the morning and evening dosages did not differ. A significant correlation was observed between plasma propranolol concentration and %R in HR during exercise in the morning (r=0.74) and evening (r=0.63) trials, and the regression lines of the morning and evening treatments did not differ. The data indicate that the suppressive effect of propranolol on exercise-induced tachycardia was relatively greater after a morning than an evening dose; that propranolol was more rapidly absorbed from the gastrointestinal tract after the morning than the evening dosage; that diurnal changes in the activity of propranolol depend in part on the time of administration and its subsequent effect on plasma concentrations of the drug; and that the antagonist activity of propranolol relative to a given drug concentration may not differ between morning and evening treatments.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of fusion energy 4 (1985), S. 289-314 
    ISSN: 1572-9591
    Schlagwort(e): SENRI-I ; pellet ; blanket ; tritium breeding ratio ; energy deposition ; radiation damage ; activity ; streaming
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract A neutronic analysis of the laser-driven inertial-confinement fusion reactor SENRI-I is presented. Three-dimensional Monte Carlo calculations were performed to examine the effects of laser beam ports on the flux distribution, tritium breeding ratio, thermal energy deposition in the blanket, and radiation streaming. A Monte Carlo code was also used for the time-dependent radiation-damage analysis accounting for the time of the flight spread of neutrons and the results are compared to the analysis for the HIBALL design. Induced radioactivity was estimated, based on the one-dimensional transport calculation and depletion analysis. The calculated results reveal the advantages of the SENRI-I design with a thick Li layer compared to other reactor systems employing a dry-wall scheme.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...