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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Terra nova 15 (2003), S. 0 
    ISSN: 1365-3121
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: In the Basle region of Switzerland we demonstrate that rockfall blocks can be dated accurately using the radiocarbon method. Soil beneath rockfall blocks containing organic macro-remains was sampled at four cliff sites in the Tabular Jura south-east of Basle. A lightweight drilling rig drills a 101-mm-diameter hole through rockfall blocks up to 6 m in height. A downhole sampler is used to recover soil samples from below the blocks. Eighteen radiocarbon dates on charcoal, wood, needles of conifers and organic macro-remains from 11 blocks gave dates between 970 and 440 bp. Calibrated ages range between ad 1210 and ad 1450. These results, along with field observations and historical research, suggest that a large number of blocks toppled as rockfalls within a short time interval in the epicentral area of the ad 1356 Basle earthquake.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Copenhagen : Munksgaard International Publishers
    Dental traumatology 16 (2000), S. 0 
    ISSN: 1600-0595
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract – Following a severe traumatic incident to permanent immature teeth, the growth of calcified tissue in the pulp space may occasionally occur. This calcified tissue may be diffuse or in intimate contact with the dentine. It has been suggested that a wide open apex, severe damage to the root sheath, and the absence of infection are only some of the predisposing factors leading to this metaplasia of pulp tissue into bone-like tissue. Five cases are described.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Clinical & experimental allergy 34 (2004), S. 0 
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Objective Epinephrine (Epi) is the treatment of choice for reversing cardiovascular collapse in anaphylactic shock (AS). In this condition, most treatment guidelines have been anecdotally derived and no randomized clinical trials have been conducted. In the present study, we examined the time course of haemodynamic recovery in a canine model of AS when Epi was administered at the initiation of allergen challenge before fully developed shock had occurred.Methods Randomized, controlled, crossover studies were performed approximately 3–5 weeks apart in ragweed-sensitized dogs while the animals were ventilated and anaesthetized. Epi was administered by bolus intravenous (i.v.), subcutaneous (s.c.), intramuscular (i.m.) routes and by continuous i.v. infusion (CI). The findings obtained in the Epi treatment (T) studies were compared with those found in a no treatment (NT) study. In the bolus studies, Epi was administered at 0.01 mg/kg, while in the CI study, the dose of Epi was titrated to maintain mean arterial pressure (MAP) at 70% of preshock levels. MAP, cardiac output (CO), stroke volume (SV), and pulmonary wedge pressure (Pwp) were determined over a 3 h period.Results In the CI study, haemodynamics (CO, MAP, and SV) were significantly higher than those measured in the NT study and the bolus studies over approximately the first hour of the study. In the CI study, the amount of Epi infused was significantly less than in the bolus studies.Conclusion When administered at the initiation of allergen challenge, bolus treatment of Epi by i.m., i.v., or s.c. routes caused limited haemodynamic improvement in AS. In contrast, constant infusion of Epi at a lower total dose produced significant haemodynamic improvement. Within the limits of this anaesthetized canine model, the results suggest that CI should be the preferred route in the treatment of AS when this treatment option is available.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The nature of dark matter remains mysterious, with luminous material accounting for at most ∼25 per cent of the baryons in the Universe. We accordingly undertook a survey looking for the microlensing of stars in the Large Magellanic Cloud (LMC) to determine the fraction of Galactic dark ...
    Materialart: Digitale Medien
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  • 5
    ISSN: 1434-0879
    Schlagwort(e): Key words Nitric oxide metabolites ; Erectile dysfunction ; Griess reaction ; Gas chromatography ; Mass spectrometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Recent research implicated that the relaxation of cavernous arterial and trabecular smooth muscle – the crucial event in penile erection – is initiated by the release of nitric oxide (NO) from nerve terminals within the cavernous tissue as well as from the endothelia that line the lacunar spaces and the intima of penile arteries. The present study was undertaken to determine whether plasma levels of the NO metabolites nitrate (NO− 3) and nitrite (NO− 2) in the systemic and cavernous blood of male subjects change during different penile conditions, and whether there is a difference in the NO− 3 and NO− 2 levels of normal males and patients with erectile dysfunction (ED). Twenty-four potent adult male volunteers and 15 patients with ED were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and, in the group of healthy volunteers, rigidity. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and NO− 3 and NO− 2 levels were determined in plasma aliquots by means of the Griess reaction and a method combining gas chromatography and mass spectrometry (GC-MS). The mean systemic and cavernous plasma NO3 −/NO2 − level in blood samples obtained from the healthy volunteers was 25–31 μM when determined by means of the Griess reaction and 37–41 μM when measured by GC-MS. Both approaches revealed that NO3 −/NO2 − levels in the peripheral and cavernous blood do not change appreciably during developing erection, rigidity and detumescence. Moreover, no significant differences were found between NO3 −/NO2 − plasma levels in the systemic and cavernous blood samples taken from the normal subjects and patients during penile flaccidity, tumescence and detumescence. Our results may reflect the fact that NO metabolism in the corpora cavernosa in the phases of penile tumescence and rigidity may account for only a minor fraction of local levels of NO3 − and NO2 −, which may also derive from exogenous sources. Moreover, the basal levels of NO metabolites in the blood flushing the lacunar spaces of the cavernous body in the state of developing erection could conceal any release of NO that may occur within the penile tissue. Thus, we conclude that the quantification of NO metabolites by means of advanced detection methods, such as GC-MS, is of no use in the workup of ED.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Der Radiologe 40 (2000), S. 103-110 
    ISSN: 1432-2102
    Schlagwort(e): Schlüsselwörter ; Kardiale Bildgebung ; Angiographie ; Nuklearmedizin ; Magnetresonanztomographie ; Computertomographie ; Key word ; Cardiac imaging ; Angiography ; Nuclear imaging ; Magnetic resonance tomography ; Computed tomography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Purpose: Cardiac imaging includes determination of the size and structure of the cardiac chambers, valves, great vessels and the coronary arteries, chamber and valvular function, myocardial perfusion, viability and metabolism. Material and methods: Chest roentgenography, angiography, echocardiography and nuclear imaging are commonly used but computed tomography and magnetic resonance imaging also offer a promising potential. Results: Coronary angiography is the gold standard in assessing coronary anatomy. Fast CT technologies such as electron-beam and multi-row-CT are promising non-invasive imaging modalities in the assessment of coronary artery disease. With intravascular ultrasound early stages of coronary atherosclerosis can be detected. For the assessment of myocardial perfusion and viability as well as cardiac function, scintigraphic methods are widely accepted. However, MRI methods have also reached a high degree of accuracy. Evaluation of chamber and valvular function is, due to its wide availability, the field of echocardiography. Conclusions: In clinical routine chest roentgenography, angiography, echocardiography and nuclear imaging are well established. The value of computed tomography and magnetic resonance imaging in the evaluation of coronary artery disease, myocardial perfusion, viability and metabolism is yet to be defined.
    Notizen: Zusammenfassung Zielsetzung: Anforderungen an die kardiale Bildgebung sind die Darstellung der Anatomie der Herzhöhlen, Herzklappen, Koronararterien und der großen Gefäße, Parameter der Ventrikel- und Klappenfunktion, der Myokardperfusion, Myokardvitalität und des myokardialen Stoffwechsels. Material und Methode: In der Bildgebung kommen neben den etablierten Standardverfahren wie Röntgen, Angiographie, Echokardiographie und nuklearmedizinischen Methoden auch neuere Verfahren der Computer- und Magnetresonanztomographie zum Einsatz. Ergebnisse: Die Koronarangiographie ist der Goldstandard in der Darstellung des gesamten Koronarsystems. In der Diagnostik der koronaren Herzerkrankung zeigen schnelle CT-Verfahren wie die Elektronenstrahltomographie (EBT) und die Mehrzeilendetektor-CT (MDCT) Vorteile gegenüber der Kernspintomographie. Frühstadien der koronaren Arteriosklerose können nur mit dem intravaskulären Ultraschall (IVUS) erkannt werden. Nuklearmedizinische Methoden sind in der Untersuchung der Myokardperfusion und -vitalität etabliert. Mit der MRT scheint eine qualitative und quantitative Bestimmung der regionalen Perfusion, Funktion und Vitalität möglich zu sein. Die Untersuchung der linksventrikulären Funktion und der Herzklappen ist die Domäne der Echokardiographie. Schlussfolgerung: In der klinischen Routine sind die Angiographie, Echokardiographie und die Nuklearmedizin etablierte Methoden. Der Stellenwert der Magnetresonanz- und Computertomographie in der Diagnostik der koronaren Herzerkrankung und der Herzfunktion, Perfusion und Vitaltät ist noch nicht definiert.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-1335
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Photosynthetica 38 (2000), S. 111-126 
    ISSN: 1573-9058
    Schlagwort(e): absorption ; bio-optical modelling ; pigments ; quantum yield ; water quality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Primary productivity in marine waters is widely estimated by the measurements of 14C incorporation, the underwater light climate, and the absorption spectra of phytoplankton. In bio-optical models the quantum efficiency of carbon fixation derived from 14C incorporation rates, the photosynthetically absorbed radiation derived from the underwater light climate, and the phytoplankton absorption spectra are used to calculate time- and depth-integrated primary productivity. Due to the increased sensitivity of commercially available fluorometers, chlorophyll a in vivo fluorescence became a new tool to assess the photosynthetic activity of phytoplankton. Since fluorescence data yield only relative photosynthetic electron transport rates, a direct conversion into absolute carbon fixation rates is not possible. Here, we report a procedure how this problem can be adressed in freshwater phytoplankton. We adapted a marine bio-optical model to the freshwater situation and tested if this model yields realistic results when applied to a hypertrophic freshwater reservoir. Comparison of primary productivity derived from 14C incorporation to primary productivity derived from Chl a fluorescence showed that the conversion of fluorescence data into carbon fixation rates is still an unsolved problem. Absolute electron transport rates calculated from fluorescence data tend to overestimate primary production. We propose that the observed differences are caused mainly by neglecting the package effect of pigments in phytoplankton cells and by non-carbon related electron flow (e.g., nitrogen fixation). On the other hand, the 14C incorporation rates can be artificially influenced by "bottle effects", especially near the water surface, where photoinhibition, photorespiration, and Mehler reaction can play a major role.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 46 (1913), S. 1814-1822 
    ISSN: 0365-9496
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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