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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 191 (1982), S. 202-204 
    ISSN: 1432-041X
    Keywords: Sperm binding ; Sea urchin eggs ; Fertilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of trypsin on the fertilizability of sea urchin eggs was studied withParacentrotus lividus andPseudocentrotus depressus. The main effects were two reductions of fertilizability, with a transient increase intervening. The first decrease was probably caused by degradation of sperm-binding sites at the vitelline sheet and the second by degradation of binding sites on the plasma membrane.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 270 (1981), S. 421-428 
    ISSN: 1432-069X
    Keywords: UV-irradiation ; Skin ; Hairless mice ; Sunscreen products ; UV-Bestrahlung ; Hautveränderungen ; haarlose Mäuse ; Sonnenschutzmittel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Weibliche haarlose Mäuse (Stamm-Mutante hr/hr) wurden mit steigenden Dosen von UV-B über eine Dauer von 4 Wochen bestrahlt. Unbehandelte Tiere dienten als Kontrolle. Weitere Gruppen von je 30 Mäusen wurden täglich vor der Bestrahlung entweder mit Leercreme oder Leermilch oder einer Milch mit Sonnenschutzfaktor 6 oder einer Creme mit Faktor 6 oder einer Creme mit Faktor 8 behandelt. Das Körpergewicht der Tiere blieb während der Behandlung im Vergleich zu den unbehandelten Kontrollen unverändert. Die Hautdicke war nach der Bestrahlung signifikant erhöht. Diese Zunahme wurde bereits durch die Leercreme oder Leermilch partiell antagonisiert. Sie wurde nach Gabe von Creme oder Milch mit Lichtschutzmitteln vollständig verhindert. Unter den gewählten Versuchsbedingungen war die Kraft bei Abriß ausgestanzter hautproben nach Bestrahlung erhöht. Diese Erhöhung wurde nicht durch die Leerzubereitungen, wohl aber durch die Zubereitungen mit UV-Absorbern, aufgehoben. Die Reißdehnung ausgestanzter Hautstreifen erwies sich als der empfindlichste Indikator. Die Erniedrigung der Reißdehnung nach Bestrahlung wurde nur teilweise durch Behandlung mit den Leerzubereitungen antagonisiert. Dagegen hatten die Sonnenschutzpräparate entsprechend ihrer Stärke einen ausgeprägten Effekt. Da die Bestrahlung sowohl eine Zunahme der Reißkraft als auch der Hautdicke bewirkten, zeigten die Parameter Reißfestigkeit und Elastizitätsmodul unter den gewählten Versuchsbedingungen keine signifikanten Änderungen. Auch Kollagen und Elastin per g Frischgewicht waren nicht signifikant verändert. Bedenkt man aber die Zunahme der Hautdicke nach Bestrahlung, die durch die Lichtfilter-substanzen verhindert wird, kann man auf eine Verhinderung der Neubildung von zusätzlichem intercellulären Material schließen. Die vorgelegten Ergebnisse bestätigen den Wert von Lichtschutzzubereitungen. Weiterhin zeigen sie eine neue Methode zur Beurteilung von Chemikalien und von Zubereitungen als Lichtschutzmittel.
    Notes: Summary Female hairless mice (strain mutant hr/hr) have been irradiated with increasing doses of UV-B over a period of 4 weeks. They were compared with untreated controls. Additional groups of 30 mice were treated with milk base or cream base or milk SPF6 or cream SPF6 or cream SPF8 daily before irradiation. No changes of body weight indicating systemic effects were found. Skin thickness was increased significantly after irradiation. These changes were partially antagonized by cream or milk bases and completely prevented by the corresponding formulations containing sunscreen agents. Under the chosen conditions ultimate load of excised skin samples was increased by irradiation. This effect was not reversed by the bases but by the sunscreen products. Ultimate strain of excised skin samples proved to be the most sensitive indicator. The decrease of ultimate strain after irradiation was partially antagonized by the bases. The sunscreen products had a more powerful effect. Due to the effects on skin thickness and ultimate load tensile strength and modulus of elasticity did not show significant changes under the chosen conditions. Likewise, collagen and elastin content per gram wet weight did not show significant changes. Considering the increase of thickness of skin which is prevented by sunscreen products one may conclude also a prevention of formation of additional intercellular material. The results prove the value of sunscreen products. Furthermore, they demonstrate a new method for evaluation of chemicals and sun protection preparations.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 7 (1981), S. 329-329 
    ISSN: 1432-1017
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 14 (1981), S. 191-202 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The present study presents the first small-angle neutron scattering experiment of lipid bilayers in excess water. The method of solvent contrast variation was applied. The variation of scattering intensity with the scattering angle could be analysed in terms of the Kratky–Porod model of scattering by quasi-two-dimensional systems. From this the bilayer thickness of unilamellar vesicles of dimyristoyllecithin was determined to be d = 41 ± 1 Å at 310 K. Several typical mixtures of different lecithins with varying chain lengths and of lecithin with phosphatidic acid were studied. By deuteration of one lipid component a very large contrast between segregated phases could be achieved. It was thus possible to distinguish clearly between homogeneous mixtures and mixtures which exhibit a heterogeneous lipid organization. In the latter case no intensity matching upon solvent contrast variation was possible. It is shown that phase boundaries may be determined very accurately by performing contrast variation experiments with at most two mixtures of different initial composition. The main advantage of the present method is that lateral phase separation may also be clearly studied in fluid states of the bilayer. From the average scattering-length densities one can determine the density of the lipid layers and thus the excess volumes of the mixtures. For lecithin mixtures positive excess volumes are observed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1459
    Keywords: Evoked potentials ; Somatosensory-evoked potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde versucht, die diagnostische Wertigkeit der SEP nach Reizung von Beinnerven (SEPL) abzustecken. Die Untersuchung von Normalpersonen ergab folgendes: 1. Die Reizung des N. suralis ist den anderen Methoden — vor allem auch der Stimulation des N. tibialis — überlegen. 2. Die Latenzzeit zeigt eine beträchtliche Streuung, die sich auch durch Berücksichtigung von Alter, Körpergröße und Hauttemperatur nicht wesentlich einengen läßt. Zudem ist sie sowohl im Kurzzeit- als auch im Langzeit-Versuch bei vielen Gesunden nicht stabil. Bei den Amplituden sollten nur extreme Rechts-Links-Differenzen verwertet werden. 3. Amplituden und Latenzzeiten variieren in Abhängigkeit von Reizintensität und -frequenz sowie von der Filterung. Angesichts der beträchtlichen Variabilität sollte man — um falsch positive Befunde zu vermeiden — die Grenzen der Normalwerte hinreichend weit abstecken. Daraus folgt, daß sich diskrete Leistungsstörungen — wie man sie bei bestimmten Polyneuropathien, Wurzelschäden und vielen intraspinalen raumfordernden Prozessen erwarten kann — dem Nachweis entziehen, während sich ausgedehnte Demyelinisierungen in jedwedem Abschnitt der sensiblen Neuronenkette gut aufdecken lassen.
    Notes: Summary An attempt was undertaken to assess the diagnostic value of sensory potentials evoked by stimulation of leg nerves. Findings in normal persons were as follows. First, stimulation of the sural nerve was superior to other methods, especially stimulation of the tibial nerve. Second, variations in latency were considerable and not attributable to age, height, or skin temperature. In many normal persons latency was not stable in either short-time or long-time trials. Amplitudes varied to such an extent that they could not help in diagnosis with the possible exception of extreme side-to-side differences. Finally, both amplitudes and latencies varied in relation to stimulus intensity, repetition rate, and filtering. Since sensory potentials from the leg nerves varied considerably, normal values must extend over a range that is wide enough to avoid mistaken diagnosis of abnormality. Hence, slight disturbances of nerve conduction such as those found in certain neuropathies, root damage and many extramedullary intraspinal space-occupying lesions could not be identified, whereas extensive demyelination in all parts of the sensory neuronal chain was readily discovered.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The total cross section fore + e − annihilation into hadrons for center of mass energies from 9.4 to 9.5 GeV has been measured with the nonmagnetic DESY-Heidelberg detector at DORIS. A value ofR=σhad/σµµ=3.8±0.7 for the continuum region around the Υ (9.46) resonance has been determined. The ratioΓ ee Γ had/Γ tot of electronic, hadronic and total widths has been reevaluated to be (1.00±0.23) keV for the Υ resonance and (0.37±0.16) keV for the Υ′. In addition, a search for directly produced pohotons from Υ decays of the type Υ→γ+gluon+gluon has been performed. The Υ decay into muon pairs has also been searched for.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Charged hadron production ine + e − annihilation is studied in the 7 to 10 GeV CM energy region and at the Υ (9.46) and Υ′ (10.01) resonances with the LENA detector at DORIS. The statistical moments of the charged multiplicities are studied. The data show KNO scaling behaviour and suggest the presence of long range correlations. An average charged multiplicityrise of Δn(Υ)=0.55±0.19 and Δn(Υ′)=1.26±0.29 over the continuum is observed for the Υ and Υ′ direct decays. The jet structure of the Υ and Υ′ direct decays is investigated using the charged particles. The polar angular distributions of the jet axis behave like 1+α(T) cos2θ with 〈α(T)〉Υ=0.7±0.3 and 〈α(T)〉Υ′=0.6±0.4. The 〈α(T)〉Υ value is in agreement with the QCD vector gluon assignment and excludes scalar gluons by more than four standard deviations.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archive for mathematical logic 22 (1980), S. 27-41 
    ISSN: 1432-0665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A search for the decays γ→ρπ, γ→J/ψX and γ→γa (whereX is undetermined and a is an axion) has been completed using the LENA detector at the DORIS storage ring. No evidence for any of these processes was found. For these decay modes we set branching fraction upper limits (90% C.L.) of 2.1×10−3, 2.0×10−2 and 9.1×10−4, respectively.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 48 (1982), S. 399-405 
    ISSN: 1439-6327
    Keywords: Motion sickness ; Car sickness ; Linear acceleration ; Linear acceleration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thirty-eight normal volunteers were tested in an ambulance car while being accelerated in one of the following positions: (1) sitting upright facing forward in the car, (2) lying supine on a stretcher head forward, (3) supine position head backward. Consecutive short periods of negative horizontal acceleration (0.7–0.95 g) were achieved by brisk braking manoeuvres of the car, followed by weak reacceleration (0.15 g). Motion sickness symptoms were observed and recorded after each experiment using a special motion sickness scaling index which was weighted according to the strength of any particular symptom. The results indicate that horizontal linear acceleration in a car, such as experienced during multiple braking manoeuvres, is an effective motion sickness provoking stimulus. Negative X-axis stimulation is more nauseogenic then acceleration in the Z-axis stimulation is more nauseogenic then acceleration in the Z-axis of the body.
    Type of Medium: Electronic Resource
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