ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

11

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LEF-1 is crucial for neutrophil granulocytopoiesis and its expression is severely reduced in congenital neutropenia (2006)

Cario, Gunnar ; Uenalan, Murat ; Schambach, Axel ; [et al.]

[s.l.] : Nature Publishing Group

Nature medicine 12 (2006), S. 1191-1197

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ISSN: 1546-170X

Source: Nature Archives 1869 - 2009

Topics: Biology , Medicine

Notes: [Auszug] We demonstrate here that lymphoid enhancer-binding factor 1 (LEF-1) mediates the proliferation, survival and differentiation of granulocyte progenitor cells. We initially documented the importance of this transcription factor in the bone marrow of individuals with severe congenital neutropenia (CN) ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/nm1474

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12

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Activity patterns of the common vole, Microtus arvalis — Automatic recording of behaviour in an enclosure (1980)

Lehmann, Ulrich ; Sommersberg, Christian W.

Springer

Oecologia 47 (1980), S. 61-75

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ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The activity behaviour of the common vole, Microtus arvalis was studied in an enclosure during a one-year cycle. The number of voles varied between 2 and 25 specimens. Emergence from burrows, running through pathways and visits at a feeding site were automatically recorded by passage counters which we developed for use in the field. The results can be summarized as follows: 1. The voles were day-active throughout the year — no change of the activity phase was observed. A significant proportion of activity at daytime was due to foraging trips to the feeding site, but the voles were active in the pathway-system, too. At night only a few short visits to the feeding site were recorded and almost no activity in the pathways was detectable. 2. In addition to the day-activity recorded by the passage counters we observed other activities like burrowing and storage almost exclusively at daytime, especially at dawn and dusk. 3. During daylight hours the voles were active on the surface in a synchronized short-term activity rhythm of about two hours. 4. This clear-cut activity pattern was changed for two reasons only: by juveniles beginning to venture from their burrows and by wet and cold weather conditions. 5. The activity pattern of voles kept in a cage within the enclosure was in accordance with previous investigations — the caged voles exhibited a distinct short-term rhythm of feeding bouts during daylight hours and showed extensive wheel-running activity at night. Thus they had maximum locomotor activity at a time, during which the voles in the enclosure were only occasionally active on the surface. Including previous results we assume from our investigations that voles are primarily day-active organisms. Although the short-term rhythm is closely related to metabolic demands there is evidence that its basic function is not to forage but to emerge for regular control of the territory. The hypothesis is put forward that short-term activity on the surface, which is synchronized with the activity of the population, might be advantageous to maintain territories. In continuation it is suggested that specimen which defend their territories effectively are most likely to survive at high densities in population cycles. Therefore the complex temporal structure of the voles' activity pattern might be favoured by selection.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00541777

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13

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Short-term and circadian rhythms in the behaviour of the vole, Microtus agrestis (L.) (1976)

Lehmann, Ulrich

Springer

Oecologia 23 (1976), S. 185-199

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ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The activity behaviour of the vole, Microtus agrestis, has been recorded in order to investigate the relationship between short-term rhythm and circadian rhythm. A simple device was developed, allowing separate monitoring of the time spent in or outside the nest, wheel-running, eating and drinking. Under natural light conditions during summer, a distinct differentiation between a short term rhythm of eating and drinking during the day-time and a circadian rhythm of wheel-running during the night was observed. The short-term rhythm depends closely on metabolic demands (hunger, thirst, excretion). Control of these demands by an endogenous oscillation could not be substantiated. The circadian rhythm of wheel-running activity is, however, controlled by an endogenous oscillation, synchronized by light conditions. It is subjected to seasonal variations. a) The threshold of light intensity below which wheel-running occurs is lowest during summer (〈0.5 lx) and is higher during spring and autum (〉 5 lx). b) Wheel-running is controlled by a circadian oscillation during summer only whereas it is an integrated part of the short-term rhythm during spring and autumn (experiments during the winter have not yet been performed). Experiments gave evidence that the properties of the cage can deeply influence the amount and pattern of wheel-running activity. It is concluded that wheel-running reflects a certain level of excitation, which may be caused by different behavioural intentions. The seasonal changes of the control of wheel-running activity are discussed with respect to this assumption. The relevancy of locomotor activity patterns as usually recorded in the laboratory to reveal the physiological and ecological significance of endogenously controlled behavioural patterns is discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00361235

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14

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Stromaufwärts gerichteter Flug von Philopotamus montanus (Trichoptera) (1970)

Lehmann, Ulrich

Springer

Oecologia 4 (1970), S. 163-175

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ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Description / Table of Contents: Zusammenfassung An einem Bachlauf in Schwedisch-Lappland wurde an vier Stellen das Vorkommen der Imagines von Philopotamus montanus durch Lichtfallen-und Handfänge erfaßt. Die Fänge wurden quantitativ und qualitativ ausgewertet und verglichen. Zwischen den einzelnen Proben ergaben sich teilweise deutliche Differenzen. 1. Die Imagines waren an der Mündung des Baches weit häufiger als am oberen Ende der Untersuchungsstrecke. 2. In den Handfängen vor der Mündung waren prozentual dreimal weniger Weibchen als weiter oberhalb am Bach. Die meisten Weibchen im Mündungsgebiet trugen unreife Eier, während am Oberlauf überwiegend Weibehen gefangen wurden, die bereits ganz oder teilweise abgelegt hatten. Reife, ablegebereite Weibchen waren an allen Untersuchungsstellen fast gleich häufig. 3. Die Fänge der Lichtfallen unterschieden sich in ihrer Zusammensetzung von den Handfängen aus ihrer Umgebung. Sie enthielten an allen Stellen doppelt so viele reife, ablegebereite Weibchen wie die Handfänge. Unreife Weibchen und solche, die bereits ganz oder teilweise abgelegt hatten, waren in den Fallen seltener. 4. Während der zehntägigen Untersuchungszeit änderte sich die Zusammensetzung der Proben, die Differenzen zwischen Ober- und Unterlauf wurden geringer. 5. Das Maximum der Fallenfänge lag in den Tagesstunden (6–22 Uhr). Das Geschlechterverhältnis hatte einen deutlichen Tagesgang, nachmittags wurden mehr Weibchen gefangen als am Vormittag. 6. Die Ergebnisse werden auf ihre methodische Zuverlässigkeit untersucht und im Hinblick auf den möglichen bachaufwärts gerichteten Flug reife, eitragender Weibchen von Fließwasserinsekten diskutiert.

Notes: Summary Imagines of Philopotamus montanus were sampled by light-traps and by hand at four sites along the Kaltisjokk in Swedish-Lappland. The samples were quantitatively and qualitatively analysed and compared. They differed in the following points: 1. There were many more imagines at the mouth of the stream than in the upper reaches. 2. At the mouth of the stream the percentage of the females was about one third compared with the samples from the upper reaches. Most of these females were immature, whereas most of the females from the upper parts had already laid their eggs. Mature females, which were ready for the first oviposition were distributed uniformly along the stream. 3. The proportion of mature females caught in the light-traps was twice that caught by hand. Immature females and females which had already laid their eggs were less numerous in the light-traps than in the hand-catches. 4. During the ten-day period of the investigation the differences between the samples from the four sites decreased. 5. With the light-traps most of the insects were caught during the day-time (6–22h). The sex ratio changed with the time of day. In the morning males dominated the catch, and in the afternoon females. 6. The reliability of the methods is discussed and the hypothesis is put forward that mature, egg-bearing females migrate upstream.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00377099

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15

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Tagesperiodisches verhalten und habitatwechsel der larven von Potamophylax luctuosus (Trichoptera) (1972)

Lehmann, Ulrich

Springer

Oecologia 9 (1972), S. 265-278

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ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Larvae instars of Potamophylax luctuosus build their cases on different material and occur in different habitats. The distribution of the instars was observed in a brook and their daily pattern of locomotory activity was studied in the laboratory. 1. First instars build their cases of plant material. They prefer habitats well exposed to light and current and they are found especially on stones. They show no preference for either diurnal or nocturnal activity and no avoidence of light. 2. Later instars change from plant to stony cases. They are found chiefly in dim habitats, where current is slow. They gradually develop negative phototaxis and nocturnal activity. In constant conditions (DD) no endogenous rhythm has been observed. 3. Late instar larvae have stony cases of fairly uniform small stones. They chiefly are found beneath stones and roots in deep water. Their activity pattern is strictly nocturnal. In constant conditions (DD) they have an endogenous rhythm with a period of about 26–27 hrs. 4. The development of negative phototaxis and nocturnal activity is correlated with the demands of the young larvae for current and food. The endogenous rhythm of activity appears only in the latest instar, during which preparation for pupation occurs. Therefore, it appears that the endogenous rhythm is of great importance for the development of pupa and imago. 5. Daily activity patterns during life history of eight species of Trichoptera are compared.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00345236

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16

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Ein Beitrag zur Kristallchemie der Kobaltoxoniobate: CoNb2O6 mit Rutilstruktur (1980)

Lehmann, Ulrich ; Müller-Buschbaum, Hanskarl

Springer

Monatshefte für Chemie 111 (1980), S. 1225-1227

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ISSN: 1434-4475

Keywords: Cobalt ; Crystal Structure ; Niobium ; Oxygen ; X-Ray

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract CoNb2O6 can be prepared by reaction of stoichiometric amounts of CoO (thermical decomposition of cobaltoxalate) and Nb2O5 in argon-atmosphere up to 1,400 °C. The isolated red-brown single crystals have tetragonal symmetry (a=472.6;c=305.4 pm; space group P42/mnm-D 4h 14 ). Electron probe micro-analysis of the single crystals verifies the composition Co0.33Nb0.67O2. Co2+ and Nb5+ occupy statistically the metal positions of the rutil-type structure. The differences between Co0.5Nb0.5O2 (CoNbO4≡AlNbO4-type) and Co0.38Nb0.67O2 (CoNb2O6) are discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00909680

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Neue helicale Moleküle, IX. Synthesen, Enantiomerentrennungen, Circulardichroismus, Racemisierungsschwellen, Röntgenstrukturanalysen und absolute Konformation neuer, gut zugänglicher Arenicene (1983)

Vögtle, Fritz ; Palmer, Michael ; Fritz, Edmund ; [et al.]

Weinheim : Wiley-Blackwell

Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3112-3124

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ISSN: 0009-2940

Keywords: Chemistry ; Inorganic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Description / Table of Contents: New Helical Molecules, IX. Syntheses, Enantiomer Separations, Circular Dichroism, Racemization Barriers, X-Ray Analyses, and Absolute Conformations of New, Easily Available ArenicenesThe new helical compounds 1-3 have been synthesized. 1 and 2 are separated into the enantiomers by chromatography on cellulose triacetate. The rotatory powers are high: e.g., [α]43620 = 2096 for 1. The racemization/ring inversion barriers range between 115 and 125 kJ/mol. X-ray analyses of 1-3 reveal different torsional angles between the rings ABC from 3.6 to 10.4°. They are compensated through the different interplanar angles of A and C with the plane B in such a way that the distance d between the intraanular C-Atoms in all compounds 1-4 is similar (2.57-2.60 Å). Correspondingly, the δ(Hi) values of 1-4 are found to differ only slightly (5.32-5.67 ppm). A determination of the absolute conformation using Bijvoets method shows (-)-2 (λ = 546 nm) to be the P-helix, and ( + )-2 the M-helix.

Notes: Die neuen helicalen Verbindungen 1-3 werden synthetisiert, 1 und 2 durch Chromatographie an Triacetylcellulose in die Enantiomeren getrennt. Die optischen Drehungen sind hoch: z. B. [α]43620 = 2096 für 1. Die Racemisierungs-/Ringinversionsbarrieren liegen zwischen 115 und 125 kJ/mol. Röntgenstrukturanalysen von 1-3 ergeben unterschiedliche Torsionswinkel zwischen den Ringen ABC von 3.6-10.4°. Sie werden durch die unterschiedlichen Interplanarwinkel von A und C mit der Ebene B derart kompensiert, daß der Abstand d zwischen den intraanularen C-Atomen bei allen Verbindungen 1-4 nahezu gleich ist (2.57-2.60 Å). Entsprechend wird auch für δ(Hi) von 1-4 eine nur geringfügig variierende Verschiebung von 5.32-5.67 ppm gefunden. Die Bestimmung der absoluten Konformation nach der Bijvoet-Methode ergab für (-)-2 (λ = 546 nm) die P-, für ( + )-2 die M-Helix-Struktur.

Additional Material: 2 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/cber.19831160910

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