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Different Waves (different + wave)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Acute Activation of Hippocampal Glucocorticoid Receptors Results in Different Waves of Gene Expression Throughout Time

JOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2006
M. C. Morsink
Abstract Several aspects of hippocampal cell function are influenced by adrenal-secreted glucocorticoids in a delayed, genomic fashion. Previously, we used Serial Analysis of Gene Expression to identify glucocorticoid receptor (GR)-induced transcriptional changes in the hippocampus at a fixed time point. However, because changes in mRNA levels are transient and most likely precede the effects on hippocampal cell function, the aim of the current study was to assess the transcriptional changes in a broader time window by generating a time curve of GR-mediated gene expression changes. Therefore, we used rat hippocampal slices obtained from adrenalectomised rats, substituted in vivo with low corticosterone pellets, predominantly occupying the hippocampal mineralocorticoid receptors. To activate GR, slices were treated in vitro with a high (100 nM) dose of corticosterone and gene expression was profiled 1, 3 and 5 h after GR-activation. Using Affymetrix GeneChips, a striking pattern with different waves of gene expression was observed, shifting from exclusively down-regulated genes 1 h after GR-activation to both up and down regulated genes 3 h after GR-activation. After 5 h, the response was almost back to baseline. Additionally, real-time quantitative polymerase chain reaction was used for validation of a selection of responsive genes including genes involved in neurotransmission and synaptic plasticity such as the corticotropin releasing hormone receptor 1, monoamine oxidase A, LIMK1 and calmodulin 2. This permitted confirmation of GR-responsiveness of 15 out of 18 selected genes. In conclusion, direct activation of GR in hippocampal slices results in transient changes in gene expression. The pattern in which gene expression was modulated suggests that the fast genomic effects of glucocorticoids may be realised via transrepression, preceding a later wave of transactivation. Furthermore, we identified a number of interesting candidate genes which may underlie the glucocorticoid-mediated effects on hippocampal cell function. [source]

Unsupervised separation of seismic waves using the watershed algorithm on time-scale images

GEOPHYSICAL PROSPECTING, Issue 4 2004
Antoine Roueff
ABSTRACT This paper illustrates the use of image processing techniques for separating seismic waves. Because of the non-stationarity of seismic signals, the continuous wavelet transform is more suitable than the conventional Fourier transforms for the representation, and thus the analysis, of seismic processes. It provides a 2D representation, called a scalogram, of a 1D signal where the seismic events are well localized and isolated. Supervised methods based on this time-scale representation have already been used to separate seismic events, but they require strong interactions with the geophysicist. This paper focuses on the use of the watershed algorithm to segment time-scale representations of seismic signals, which leads to an automatic estimation of the wavelet representation of each wave separately. The computation of the inverse wavelet transform then leads to the reconstruction of the different waves. This segmentation, tracked over the different traces of the seismic profile, enables an accurate separation of the different wavefields. This method has been successfully validated on several real data sets. [source]

Acute Activation of Hippocampal Glucocorticoid Receptors Results in Different Waves of Gene Expression Throughout Time

Cover Picture: Laser Phys.

LASER PHYSICS LETTERS, Issue 6 2010
Lett.
In the calculations, we also have a very special angular distribution for the slow electrons observed in the case of Ti:Sapphire laser pulse. The appearance of slow electrons is clearly demonstrated at the angularlyresolved 2D momentum distribution which low-energy part is presented in this figure. The observed 2D low-momentum distribution seems to be very consistent with the total momentum distribution: the angular directions of preferable electron ejection can be evidently seen. At other directions, the electron ejection is suppressed. The appearance of such directions of predominant or suppressed electron ejection results from the interference of the different waves in electron wave packet during its recollision with the parent ion. (Cover picture: I.A. Burenkov, A.M. Popov, et al., pp. 409,434, in this issue) (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Number of Follicular Waves and Their Effect on Pregnancy Rate in the Cow

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2005
HA Çelik
Contents In the study, the relationship of follicular growth waves, oestradiol and pregnancy rates were investigated during oestrus cycle in cows. A total of 22, Brown Swiss cows (3,5 years old) were used for the study. The ovaries of animals were examined from sixth day of cycle to next oestrus by ultrasound. The follicles that were present in the ovarium were recorded. Follicular growth was observed every day by means of ultrasound examination. The blood samples were taken for analysis of oestradiol simultaneously with ultrasound examinations. The oestrus animals were inseminated. Each animal that inseminated was examined by ultrasound on day 28 after insemination for pregnancy diagnosis. Two follicular growth waves were observed in nine of 22 (40.9%), three waves in 13 of 22 (59.1%) animals. The oestradiol was found in the same concentration but in different release patterns between two and three waves animals. Pregnancy rate in cows with three and two follicular waves did not differ. In conclusion, emergence of three waves of follicular growth was higher in Brown Swiss cows, the analysis of oestradiol could be used for determination of the wave numbers and the animals with different waves may have had the same pregnancy rates. [source]