300 research outputs found
Restoration of peripheral V2 receptor vasopressin signaling fails to correct behavioral changes in Brattleboro rats.
Beside its hormonal function in salt and water homeostasis, vasopressin released into distinct brain areas plays a crucial role in stress-related behavior resulting in the enhancement of an anxious/depressive-like state. We aimed to investigate whether correction of the peripheral symptoms of congenital absence of AVP also corrects the behavioral alterations in AVP-deficient Brattleboro rats. Wild type (WT) and vasopressin-deficient (KO) male Brattleboro rats were tested. Half of the KO animals were treated by desmopressin (V2-receptor agonist) via osmotic minipump (subcutaneous) to eliminate the peripheral symptoms of vasopressin-deficiency. Anxiety was studied by elevated plus maze (EPM), defensive withdrawal (DW) and marble burying (MB) tests, while depressive-like changes were monitored in forced swimming (FS) and anhedonia by sucrose preference test. Cell activity was examined in septum and amygdala by c-Fos immunohistochemistry after 10min FS. KO rats spent more time in the open arm of the EPM, spent less time at the periphery of DW and showed less burying behavior in MB suggesting a reduced anxiety state. KO animals showed less floating behavior during FS revealing a less depressive phenotype. Desmopressin treatment compensated the peripheral effects of vasopressin-deficiency without a significant influence on the behavior. The FS-induced c-Fos immunoreactivity in the medial amygdala was different in WT and KO rats, with almost identical levels in KO and desmopressin treated animals. There were no differences in central and basolateral amygdala as well as in lateral septum. Our data confirmed the role of vasopressin in the development of affective disorders through central mechanisms. The involvement of the medial amygdala in the behavioral alterations of vasopressin deficient animals deserves further attention
Multidimensional analysis of Fermi GBM gamma-ray bursts
The Fermi GBM catalog provides a large database with many measured variables
that can be used to explore and verify gamma-ray burst classification results.
We have used Principal Component Analysis and statistical clustering techniques
to look for clustering in a sample of 801 gamma-ray bursts described by sixteen
classification variables. The analysis recovers what appears to be the Short
class and two long-duration classes that differ from one another via peak flux,
with negligible variations in fluence, duration and spectral hardness. Neither
class has properties entirely consistent with the Intermediate GRB class.
Spectral hardness has been a critical Intermediate class property. Rather than
providing spectral hardness, Fermi GBM provides a range of fitting variables
for four different spectral models; it is not intuitive how these variables can
be used to support or disprove previous GRB classification results.Comment: accepte
Ruthenium Oxidation in High Temperature Air and Release of Gaseous Ruthenium KFKI-3/2008
The RUSET experimental programme was launched in order to study Ru oxidation and
release from fuel in high temperature air. More than forty small scale tests have been
performed with mixed powder components of inactive materials and with short fuel rods.
The influence of temperature, air flow rate and the presence of other fission products on the
gaseous Ru release and the retention role of fuel pellets and cladding have been
investigated. The test series indicated that if an air ingress type severe accident occurs most
of the initial Ru mass can be released from the reactor core to the containment or
environment. Some part of the released gaseous Ru undergoes precipitation and deposits on
the cold surfaces, another part is released in gaseous form. The deposited Ru oxides can
serve as a secondary source for further gaseous Ru releas
Transverse kink oscillations of expanding coronal loops
We investigate the nature of transverse kink oscillations of loops expanding
through the solar corona and how can oscillations be used to diagnose the
plasma parameters and the magnetic field. In particular, we aim to analyse how
the temporal dependence of the loop length (here modelling the expansion) will
affect the P1 /P2 period ratio of transverse loop oscillations.
Due to the uncertainty of the loop's shape through its expansion, we discuss
separately the case of the loop that maintains its initial semi-circular shape
and the case of the loop that from a semi-circular shape evolve into an
elliptical shape loop. The equations that describe the oscillations in
expanding flux tube are complicated due to the spatial and temporal dependence
of coefficients. Using the WKB approximation we find approximative values for
periods and their evolution, as well as the period ratio. For small values of
time (near the start of the expansion) we can employ a regular perturbation
method to find approximative relations for eigenfunctions and eigenfrequencies.
Using simple analytical and numerical methods we show that the period of
oscillations are affected by the rising of the coronal loop. The change in the
period due to the increase in the loop's length is more pronounced for those
loops that expand into a more structured (or cooler corona). The deviation of
periods will have significant implications in determining the degree of
stratification in the solar corona. The effect of expansion on the periods of
oscillations is considerable only in the process of expansion of the loop but
not when it reached its final stage
Change of composition and diversity of species and grassland management between different grazing intensity in Pannonian dry and wet grasslands
Investigations were carried out in wet and dry pasture. Coenological recordings were taken in
three zones. The first zone (âAâ) located 0-50 m near the stable, second zone (âBâ) located 50-150 m
from the stable, while the third zone (âCâ) located farther than 150 m. We have carried out analyses of
ecological and environmental factors and life form types. Based on our results for both dry and wet
grasslands, quadrates of âAâ zone were well isolated from the rest of the zones. Overgrazing, which
involves considerable trampling, vanishes differences among vegetations, thereby promotes weed and
disturbance tolerant rich vegetation. The lowest species number and diversity could be found here. Due to
the nitrogen enrichment due to the constant presence of livestock, drier and less heat demanding habitat
developed in the âAâ zones, according to the environmental indicators. Because of the change in
management, conservation and diversity values of âCâ zone increased, however, according to nature
protection values it underperformed compared to âBâ zone. According to the sample area, wet grasslands
from the sandy areas of KiskunsĂĄg, preserve nature protection values and grass composition better
moving away from stables, due to less grazing pressure. Drier backgrounds tolerate stronger grazing
pressure
Synergistic Effect of Ketone and Hydroperoxide in BrĂžnsted Acid Catalyzed Oxidative Coupling Reactions
Waste not wasted: A mechanistic study of the autoxidative coupling of xanthene with cyclopentanone uncovered an autoinductive effect of the waste product hydrogen peroxide. It generates radicals in the presence of acid and ketones, which accelerate the reaction by providing an additional pathway to the reactive hydroperoxide intermediate. This discovery could be applied to achieve other BrĂžnsted acid-catalyzed oxidative coupling reactions
Extracellular deposition of matrilin-2 controls the timing of the myogenic program during muscle regeneration.
Here, we identify a role for the matrilin-2 (Matn2) extracellular matrix protein in controlling the early stages of myogenic differentiation. We observed Matn2 deposition around proliferating, differentiating and fusing myoblasts in culture and during muscle regeneration in vivo. Silencing of Matn2 delayed the expression of the Cdk inhibitor p21 and of the myogenic genes Nfix, MyoD and Myog, explaining the retarded cell cycle exit and myoblast differentiation. Rescue of Matn2 expression restored differentiation and the expression of p21 and of the myogenic genes. TGF-ÎČ1 inhibited myogenic differentiation at least in part by repressing Matn2 expression, which inhibited the onset of a positive-feedback loop whereby Matn2 and Nfix activate the expression of one another and activate myoblast differentiation. In vivo, myoblast cell cycle arrest and muscle regeneration was delayed in Matn2(-/-) relative to wild-type mice. The expression levels of Trf3 and myogenic genes were robustly reduced in Matn2(-/-) fetal limbs and in differentiating primary myoblast cultures, establishing Matn2 as a key modulator of the regulatory cascade that initiates terminal myogenic differentiation. Our data thus identify Matn2 as a crucial component of a genetic switch that modulates the onset of tissue repair
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