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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Insect Physiology 40 (1994), S. 715-722 
    ISSN: 0022-1910
    Keywords: Activity ; Arctic ; Climate change ; Collembola ; Freeze avoidance ; Oxygen uptake ; Survival
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1939
    Keywords: Aphid ; Arctic ; Climate change ; Life-cycle ; Thermal budget
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A manipulation experiment was carried out on a field population of the aphid Acyrthosiphon svalbardicum near Ny Ålesund, on the high arctic island of Spitsbergen, using cloches to raise temperature. An average rise in temperature of 2.8 deg. C over the summer season markedly advanced the phenology of both the host plant Dryas octopetala and the aphid. Advanced aphid phenology, with concomitant increases in reproductive output and survival, and successful completion of the life-cycle led to an eleven-fold increase in the number of overwintering eggs. Thermal budget requirements in day degrees above 0°C were calculated for key life-cycle stages of the aphid. Temperature data from Ny Ålesund over the past 23 years were used to calculate thermal budgets for the field site over the same period and these were compared with the requirements of the aphid. Each estimated thermal budget was then adjusted to simulate the effect of a +2, +4, and −2deg. C change in average temperature on aphid performance. This retrospective analysis (i) confirms that the life-cycle of A. svalbardicum is well suited to exploit higher summer temperatures, (ii) indicates that the annual success of local populations are sensitive to small changes in temperature and (iii) suggests that the aphid is living at the limits of its thermal range at Ny Ålesund based on its summer thermal budget requirements.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Magnetresonanz (MR) ; MR-Tomographie ; MR-Spektroskopie ; Relaxometrie ; Fett-/Wasser-Analyse ; Knochenmarkmetastasen ; Knochenmarkinfiltration ; Granulozytenkoloniestimulierender Faktor (G-CSF) ; Keywords Magnetic resonance (MR) ; MR-tomography ; MR-spectroscopy ; Relaxometry ; Fat-/water-analysis ; Bone marrow metastasis ; Bone marrow infiltration ; Granulocyte colony stimulating factor (G-CSF)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Aim. To study the effect of G-CSF therapy directly by MRI and 1H MRS in the lumbar and femoral bone marrow and differentiate between malignant bone marrow infiltration (MBMI) and reconversion of red marrow Methods. Thirteen patients could be examined twice, before and during G-CSF medicatio and another six only during treatment. T1 weighted spin-echo and opposed-phase gradient-echo images as well as the spectroscopic data (T2 values, water content) were analysed. Results. After G-CSF a pathologic bone marrow signal intensity was seen in 8/13 (lumbar) and 11/13 (femoral) patients respectively. The majority of the signal alterations were diffuse (6 and 8), the minority focal (2 and 3). If a patient was successfully stimulated, a significant increase in water content occured (21% lumbar, 34% femoral). T2 values did not change significantly, nor did they correlate with the stimulation success. Conclusions. MR tomography and -spectroscopy are suitable to detect lumbar and femoral bone marrow stimulation by G-CSF quantitatively and qualitatively. The changes may simulate MBMI. The adequate judgement of G-CSF treated bone marrow without pretherapeutic images is not possible.
    Notes: Zusammenfassung Ziel. Ziel dieser Studie war die Beschreibung der Auswirkungen einer G-CSF-Medikation auf Magnetresonanztomographie (MRT) und -spektroskopie (MRS) des lumbalen und femoralen Knochenmarks unter besonderer Berücksichtigung potenzieller Probleme in der Differenzialdiagnose zwischen malignen Knochenmarkinfiltrationen (KMI) und Rekonversionsphänomenen im Rahmen der Knochenmarkstimulation. Methode. Vor und während der G-CSF-Therapie wurden 13 Patienten untersucht, nur während der Therapie 6 weitere. Die Ergebnisse der Bildanalyse T1-gewichteter und fettunterdrückter gegenphasierter Aufnahmen und der spektroskopischen Daten (T2-Zeiten, Wasseranteil) wurden vor und während der Therapie verglichen und im Vergleich zu Patienten mit bekannter Knochenmarkinfiltration im Rahmen maligner Grunderkrankungen analysiert. Ergebnisse. Nach G-CSF-Medikation wurde bei 8/13 (lumbal) bzw. 11/13 (femoral) Patienten in T1w- und opGE-Bildgebung ein pathologischer Knochenmarkbefund erhoben. Die Veränderung waren in der Mehrzahl diffus (6 bzw. 8), seltener fokal (2 bzw. 3). Bei den erfolgreich stimulierten Patienten wurde ein signifikanter Anstieg der Wasserfraktion nachgewiesen (+17 bzw. +24%). Die T2-Zeiten änderten sich nicht signifikant und korrelierten nicht mit dem Stimulationserfolg. Diskussion. Die MRT und MRS der LWS sind geeignet, die zentrale Knochenmarkstimulation nach G-CSF-Medikation qualitativ und (semi)quantitativ zu erfassen. Der G-CSF-Effekt kann das Bild einer malignen KMI simulieren. Die Beurteilung einer möglichen malignen KMI ist daher ohne Ausgangsbefund nach G-CSF-Therapie nicht möglich.
    Type of Medium: Electronic Resource
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