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  • 1
    ISSN: 1432-0789
    Keywords: Key words Methane oxidation ; Land use ; Fertilization ; Pesticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In a first experiment, the effect of land use on the uptake rate of atmospheric CH4 was studied in laboratory incubations of intact soil cores. A soil under deciduous forest showed the highest CH4 oxidation. Its overall CH4 uptake during the measuring period (202 days) was 1.03 kg CH4 ha–1. Natural grassland showed the second highest CH4 oxidizing capacity (0.71 kg CH4 ha–1). The overall amount of CH4 uptake by fertilized pasture was 0.33 kg CH4 ha–1. CH4 oxidation in arable soils with different fertilizer treatments varied between 0.34 and 0.37 kg CH4 ha–1. Undisturbed soils had a higher CH4 uptake capacity than agricultural soils. The moisture content of the soil was found to be an important parameter explaining temporal variations of CH4 oxidation. Different methods of fertilization which had been commenced 10 years previously were not yet reflected in the total CH4 uptake rate of the arable soil. In a second experiment, a number of frequently used pesticides were screened for their possible effect on CH4 oxidation. In a sandy arable soil lenacil, mikado and oxadixyl caused significantly reduced CH4 oxidation compared to the control. Under the same conditions, but in a clayey arable soil, mikado, atrazine and dimethenamid caused a reduction of the CH4 uptake. In a landfill cover soil, with a 100-fold higher CH4 oxidation rate, no inhibition of CH4 oxidation was observed, not even when the application rate of pesticides was tenfold higher than usual.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Heat and mass transfer 6 (1973), S. 25-31 
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Diese Arbeit befaßt sich sowohl theoretisch als auch experimentell mit dem Einfluß eines äußeren elektrischen Feldes auf den Wärmeübergang zu einer Sonde (Röhrchen), die sich in einem hochionisierten atmosphärischen Argon-Plasmastrom befindet. Es werden wassergekühlte, blanke Kupferröhrchen als auch solche, die mit einer dünnen Pyrexglasschicht überzogen sind, als Sonden benutzt. Messungen zeigen denselben Wärmestrom für beide Sondentypen solange die blanke Sonde lokal auf dem Potential einer stromlosen Sonde gehalten wird. Dieses Ergebnis wird auf die ungehinderte Rekombination von Elektronen mit Ionen auf der isolierenden Oberfläche zurückgeführt. Vergleiche zwischen Experiment und Theorie zeigen, daß die durch die thermische und Konzentrationsgrenzschicht diffundierenden Ionen nur auf der Sondenoberfläche rekombinieren, d. h. die Grenzschicht ist chemisch „eingefroren”.
    Notes: Abstract The effect of an applied electrical potential on heat transfer to a tube immersed in a highly ionized flow of atmospheric pressure Argon plasma is experimentally and analytically determined. Bare copper tubes as well as pyrex coated tubes are utilized and the measured heat fluxes to the locally floating copper surfaces are found to be identical to those of pyrex coated surfaces. This effect is due to unimpeded recombination of electrons with ions on the insulating surface. Comparisons of experiment with analysis indicate that ions diffusing through the thermal and concentration boundary layers surrounding the tube recombine only at the wall (i. e., frozen chemistry prevails in the boundary layers).
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  • 3
    ISSN: 1432-1106
    Keywords: Cerebral cortical neurones ; Intracellular recording ; Comparative data from neurones in vivo and in vitro
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Because neurones in isolated brain slices are abnormal in several respects, we have compared the electrical properties of neocortical neurones from the anaesthetized rat with neurones from slices of the same area of neocortex in vitro. Resting potentials were not significantly different but there was a small increase in mean spike amplitude and threshold in slices. The most striking observation was a doubling of the mean apparent input resistance (Rin) of neurones in slices (36 MΩ cf. 18 MΩ in vivo). To assess the extent to which the loss of surface membrane of neurones in slices might contribute to the raised Rin, we estimated the membrane capacity of neurones in the two samples from calculations of the membrane time constants. The mean membrane capacity was significantly lower in neurones from slices, being 2/3 that of the in vivo sample, showing that recordings were indeed mostly from smaller cells in the slices. Possible causes of the difference in mean input resistance not attributable to neuronal size are also discussed.
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  • 4
    ISSN: 1433-0385
    Keywords: Key words: Malignant melanoma ; Lymph node metastases ; Lymph node dissection ; Prognosis. ; Schlüsselwörter: Malignes Melanom ; Lymphknotenmetastasierung ; Lymphknotendissektion ; Prognose.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Die Indikation zur elektiven Lymphknotendissektion, ihre evtl. zukünftige Bedeutung als Stagingmaßnahme vor adjuvanten Therapieverfahren, die Prognose der therapeutischen Dissektion sowie die Identifizierung des Pförtner-Lymphknotens und die daraus sich ergebenden therapeutischen Konsequenzen sind die wichtigsten Aspekte der Lymphknotendissektion beim malignen Melanom. Die Indikation zur elektiven Dissektion orientiert sich nicht nur an der pT-Kategorie, sondern auch an der Tumorlokalisation, dem Tumortyp und dem Geschlecht des Patienten. Ein allgemein akzeptierter Konsens zur Auswahl der in Frage kommenden Patienten besteht noch nicht. Da die ersten Studien mit Chemo-/Immuntherapie bei nodal positiven Patienten eine Prognoseverbesserung zeigen, muß zukünftig auch die Lymphknotendissektion als Stagingmaßnahme diskutiert werden. Neue Anregungen wurden in den letzten Jahren durch die Identifikation des Pförtner(„sentinel“)-Lymphknotens eingebracht. Diese Methodik bedarf noch der weiteren Evaluierung, dürfte aber zukünftig einen wesentlichen Einfluß auf die Indikation zur elektiven Lymphknotendissektion nehmen. Mit eingetretener Lymphknotenmetastasierung verschlechtert sich die Prognose des malignen Melanoms global um 20–50 %, abhängig vom Ausmaß der Metastasierung. Die Thematik wird anhand der eigenen Ergebnisse diskutiert.
    Notes: Summary. Elective lymph node dissection and its potential as a staging procedure, the prognosis of established lymph node metastases and the sentinel lymph node identification procedure are the most important aspects of lymph node dissection in malignant melanoma. It is widely accepted that subgroups of patients benefit from elective lymph node dissection. The question of which parameters identify the relevant patients properly is still under discussion. pT-categories are the most important prognostic factor; however, localisation and type of tumour and the sex of the patients are additional parameters influencing patient selection. Recently, the first studies have identified subgroups of nodal positive patients who would profit from adjuvant chemo-/immunotherapy. Therefore, lymph node dissection as a staging procedure has to be discussed in the future. Identification of the sentinel lymph node is receiving increasing attention because of its potential influence on the reassessment of elective lymph node dissection. However, this method needs further evaluation. If lymph node metastases have occurred, the prognosis of malignant melanoma decreases by 20 %–50 %, depending on the extent of metastasis in the individual case. The relevant topics and results are discussed on the basis of data of the Surgical Department of the University Hospital of Erlangen-Nuremberg.
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  • 5
    ISSN: 1433-0407
    Keywords: Schlüsselwörter ALS ; Neurogenetik ; Exzitatorische Aminosäuren ; Cu/Zn-SOD ; Key words Amyotrophic lateral sclerosis ; Neurogenetics ; Excitatory amino acids ; Cu/Zn SOD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary At presently, the etiology and pathogenesis of amyotrophic lateral sclerosis (ALS) are unknown. In recent years, the genetic background of hereditary motor neuron diseases has been partly defined. In particular, these advances represent an opportunity to improve our understanding of the pathogenesis of the familial and sporadic forms of ALS and thus provide a basis for rational therapeutic approaches. In this article, recent findings on the pathogenesis of the familial form of ALS and their implications for the sporadic form are discussed.
    Notes: Zusammenfassung Die Ätiologie und Pathogenese der amyotrophen Lateralsklerose (ALS) bleibt weitgehend ungeklärt. In den zurückliegenden Jahren sind bei den genetisch bedingten Varianten dieser Erkrankung wichtige Fortschritte bei der Identifizierung ihrer molekularbiologischen Grundlagen gemacht worden. Diese Fortschritte berechtigen zu der Hoffnung, daß es in Zukunft gelingt, die Pathogenese der familiären, aber auch der sporadischen Formen der Erkrankung zu erhellen und damit rationalen Therapieansätzen weiter den Weg zu bereiten. Im Rahmen dieser Übersichtsarbeit soll sowohl auf die vorliegenden Befunde bei der familiären Form der ALS (fALS) als auch auf die mögliche Bedeutung dieser Befunde für pathogenetische Vorstellungen bei der sporadischen Form der ALS (sALS) eingegangen werden.
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  • 6
    ISSN: 1432-0428
    Keywords: Key words Type II diabetes mellitus ; diabetic nephropathies ; epithelial cell ; glomerulus ; Indians ; North American.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. The predictive value of glomerular structure on progression of renal disease was examined in patients with Type II (non-insulin-dependent) diabetes and microalbuminuria (urinary albumin-to-creatinine ratio = 30–299 mg/g). Methods. Kidney biopsy specimens were obtained from 16 diabetic Pima Indians (6 men, 10 women). Progression of renal disease was assessed by measuring urinary albumin excretion 4 years after the biopsy (UAE4 years) and by computing the change in urinary albumin excretion during the study (Δ UAE). Results. At baseline, the duration of diabetes averaged 13.3 years (range = 4.0–23.8 years) and the mean glomerular filtration rate was 159 ml · min–1· 1.73m–2 (range = 98 – 239 ml · min–1· 1.73m–2). Median urinary albumin excretion was 67 mg/g (range = 25–136 mg/g) and it increased to 625 mg/g (range = 9–13471 mg/g) after 4 years; 10 subjects (63 %; 4 men, 6 women) developed macroalbuminuria (urinary albumin-to-creatinine ratio ≥ 300 mg/g). Neither mean arterial pressure nor HbA1 c changed substantially during follow-up. Among the glomerular morphologic characteristics, the number of visceral epithelial cells, or podocytes, per glomerulus was the strongest predictor of renal disease progression (UAE4 years, r = –0.49, p = 0.05; ΔUAE, r = –0.57, p = 0.02), with fewer cells predicting more rapid progression. Glomerular basement membrane thickness did not predict progression (UAE4 years, r = 0.11, p = 0.67; ΔUAE, r = 0.09, p = 0.73) and mesangial volume fraction had only a modest effect (UAE4 years, r = 0.42, p = 0.11; ΔUAE, r = 0.48, p = 0.06). Conclusion/interpretation. Whether lower epithelial cell number per glomerulus among those that progressed was due to cellular destruction, a reduced complement of epithelial cells, or both is uncertain. Nevertheless, these findings suggest that podocytes play an important part in the development and progression of diabetic renal disease. [Diabetologia (1999) 42: 1341–1344]
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  • 7
    ISSN: 1432-072X
    Keywords: Bacterial sulfur oxidation ; Cytochromes c ; Bacterial taxonomy ; Electron transfer proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four cytochromes were isolated from soluble extracts of the aerobic sulfur bacterium, Thiobacillus neapolitanus. The two most abundant proteins were purified to homogeneity and thoroughly characterized. Cytochrome c-554 (547) is a monomeric, small molecular weight protein which is unusual in having two well-resolved alpha peaks in UV-visible absorption spectra. The redox potential is 208 mV. Native cytochrome c-549 is oligometric, but has a subunit size of about 26.000. The yield of this protein could be improved dramatically by washing membranes with 30% ammonium sulfate, but the material solubilized by this method had a larger native molecular weight than that in the initial 0.1 M Tris-Cl extract and behaved differently on chromatography. The properties of cytochrome c-549 including subunit size and UV-visible absorption spectra are similar to mitochondrial cytochrome c 1 and chloroplast cytochrome f, which suggests that it may be a modified form of the predominant membrane cytochrome. Based on cytochrome content, it is suggested that T. neapolitanus is not closely related to other thiobacilli.
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  • 8
    ISSN: 1435-1285
    Keywords: Key words Coronary heart disease – dynamic stress echocardiography – normative values – heart rate – lactate ; Schlüsselwörter Koronare Herzerkrankung – dynamische Streßechokardiographie – Normwerte – Herzfrequenz – Laktat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 25 Patienten mit koronarer Herzerkrankung (KHK, 62 ± 9 Jahre) und 18 Herzgesunde (28 ± 6 Jahre) absolvierten je eine stufenförmige fahrradergometrische Belastung in sitzender Position und eine Streßechokardiographie in halbliegender Linksseitenlage. Während sich bei den Gesunden für die Herzfrequenz, den Blutdruck und das Druck-Frequenz-Produkt keine wesentlichen Unterschiede zwischen den beiden Belastungsformen nachweisen ließen (2 × 3 ANOVA, t-Tests mit α-Adjustierung), zeigten die KHK-Patienten auf gleichen Belastungsstufen signifikant höhere Herzfrequenzen und ein signifikant höheres Druck-Frequenz-Produkt (bei 50 W: 15 300 ± 2793 mmHg/min vs. 13 822 ± 3042 mmHg/min; bei 75 W. 18 028 ± 3479 mmHg/min vs. 16 337 ± 2619 mmHg/min) bei der Streßechokardiographie im Vergleich zur Fahrradergometrie in sitzender Position. Keine Unterschiede fanden sich in dieser Gruppe für den systolischen Blutdruck; der diastolische Blutdruck war lediglich in Ruhe und bei der Eingangsstufe von 50 W im Sitzen höher. Die Laktatkonzentrationen (nur bei den Gesunden gemessen) lagen auf allen Belastungsstufen der Streßechokardiographie signifikant höher, die Leistung an der individuellen anaeroben Schwelle (IAS) war signifikant niedriger. Schlußfolgernd besteht für Gesunde bei der Streßechokardiographie im Vergleich zur herkömmlichen Fahrradergometrie auf gleichen Belastungsstufen eine höhere metabolische bei vergleichbarer kardiozirkulatorischer Beanspruchung. KHK-Patienten hingegen erfahren in der halbliegenden Linksseitenlage eine höhere Belastung für das Herz-Kreislauf-System gegenüber der sitzenden Körperposition. Es ist bei Untersuchungen dieser Patienten mit um etwa 8 Schläge/min höheren Herzfrequenzen auf den einzelnen Stufen zu rechnen.
    Notes: Summary 25 patients with coronary heart disease (CHD, 62 ± 9 years) and 18 subjects free from cardiovascular disease (28 ± 9 years) were tested on a cycle ergometer using a graded incremental test protocol: a) in the common upright position, b) as dynamic stress echocardiography in a semi-supine position. Whereas no relevant differences could be detected between the two conditions for the healthy subjects concerning heart rate, blood pressure, and rate-pressure product (2 × 3 ANOVA, t-test with α-adjustment), the CHD patients showed both significantly higher heart rates as well as a significantly higher rate-pressure product (50 W: 15 300 ± 2973 mmHg/min vs. 13 822 ± 3042 mmHg/min; 75 W: 18 028 ± 3479 mmHg/min vs 16 337 ± 2619 mmHg/min) on equivalent stages during stress echocardiography if compared to the sitting position. There were no differences for systolic blood pressure in this group; the diastolic values were higher in the sitting position at rest and during 50 W. Lactate concentrations (determined only in the healthy subjects) were significantly higher on all stages during dynamic stress echocardiography. The workload at the individual anaerobic threshold (IAT) was significantly lower. In conclusion, we found a higher metabolic along with a similar cardiovascular strain at equivalent workloads in stress echocardiography compared to upright bicycle ergometry for healthy subjects. However, CHD patients have a higher cardiocirculatory load in the semi-supine position. When investigating these patients with stress echocardiography, higher heart rates of about 8 beats/min have to be expected for equivalent workloads if compared to the upright position.
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  • 9
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pooled parotid saliva was dialyzed in cellophane membranes against water for periods of up to 1 week and loss of proteins was monitored by acrylamide gel-electrophoresis. A gradual loss of cationic proteins was observed whereas anionic proteins were not appreciably affected. Loss of the cationic proteins could be greatly reduced by performing dialyses against dilute electrolyte solutions rather than water. These effects were attributed primarily to electrostatic charges associated with the dialysis membranes.
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  • 10
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Eine neue organische Substanz, 3, 3′-bis (trifluoromethyl)tetranitrodiphenylamine ist synthetisch hergestellt worden. Die antibakteriellen Eigenschaften gegen Gram-positive Bakterien und gegen Sulfadiazin resistente und empfindliche Arten vonNeisseria meningitidis werden beschrieben.
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