•TC-2153 administration attenuates 5-HT2A receptor functional activity in the brain.•Chronic TC-2153 administration produces antidepressant-like effect.•TC-2153 decreases the DOI-induced c-Fos ...expression in the primary neuron cultures.
The serotoninergic 5-HT2A receptor is involved in the mechanism of depression and antidepressant drugs action. Earlier we showed that striatal-enriched protein tyrosine phosphatase (STEP) inhibitor – 8-(trifluoromethyl)-1,2,3,4,5-benzopentathiepin-6-amine hydrochloride (TC-2153) affects both the brain serotoninergic system and the brain-derived neurotropic factor that are known to be involved in the psychopathology of depression. In the present study we investigated the effects of chronic TC-2153 administration on behavior in the standard battery of tests as well as the effects of acute and chronic TC-2153 treatment on the brain 5-HT2A receptors in mice. We obtained a prominent antidepressant-like effect of chronic TC-2153 treatment in the forced swim test without any adverse side effects on locomotor activity, anxiety, exploration, motor skill and obsessive–compulsive-like behavior. Moreover, both acute and chronic TC-2153 administration inhibited the functional activity of 5-HT2A receptors estimated by the number of 2,5-dimethoxy-4-iodoamphetamine (DOI, agonist of 5-HT2A receptors)-induced head-twitches. TC-2153 treatment also attenuated the DOI-induced c-fos expression in cortical and hippocampal neurons and reduced the 5-HT2A receptor protein level in the hippocampus and frontal cortex, but not in the striatum. Taken together, our combined data demonstrate that the antidepressant effect of STEP inhibitor TC-2153 could be mediated by its inhibitory properties towards the 5-HT2A receptor-mediated signaling.
The aim of the work is to develop a mechanism for cross-border carbon regulation for countries importing products to the EU, which will equally allow importing countries to fulfill the conditions of ...the Carbon Border Adjustment Mechanism (CBAM), encourage manufacturers to reduce CO2 emissions, and also provide importing countries with opportunities to replenish their budget by introducing paid emission quotas greenhouse gases. The work makes a significant contribution to stimulating the reduction of CO2 emissions by producers due to the proposed tax mechanism and preventing the leakage of greenhouse gases on the territory of third countries according to the CBAM policy. The EU evaluates double taxation, so if a carbon tax has been withdrawn in the territory of the exporting country, then such a tax will not be levied again in the EU. All this involves stimulating exporting countries by creating their own taxation systems, which will have international qualifications and be recognized by countries around the world. When choosing a taxation mechanism, it is important to choose the specifics for visiting group gases. The study was conducted on the basis of methods of comparison, modeling, analysis and deduction.
Mass measurements of 49,50Sc, 70As, 73Br and 196Hg nuclides produced at CERN's radioactive-ion beam facility ISOLDE are presented. The measurements were performed at the ISOLTRAP mass spectrometer by ...use of the multi-reflection time-of-flight and the Penning-trap mass spectrometry techniques. The new results agree well with previously known literature values. The mass accuracy for all cases has been improved.
Using the living nickel(II)-mediated polymerization of carbodiimides, the chiral (R)- or (S)-N-1-phenethyl-N′-methylcarbodiimide (PMC) monomers were polymerized with a new TIPS protected alkyne ...functional nickel initiator forming PPMC with an excess single-handed screw sense and the alkyne moiety covalently attached to the terminus of the polymer, as confirmed by 1H NMR and MALDI-TOF MS. After deprotection, the alkyne end groups of rigid-rod PPMC-2 were coupled with azide-terminated, random-coil PS and PEG homopolymers forming a novel class of helical-b-coil block copolymers. In the thin-film, all synthesized diblock copolymers formed interesting nanofibular morphologies when subject to specific conditions. The triblock RCP-4, however, adopted unique macroporous morphology as identified by AFM and SEM with average pore diameters of ca. 832 ± 194 nm. The origin of this was found to be associated with the ordering of large, hollow vesicle aggregates upon solvent evaporation followed by the melting of these aggregates filling in the hollow interior forming the submicron pores observed. Furthermore, the size of these aggregates can be easily modulated in a linear fashion from 272 to 1648 nm simply by increasing the concentration of RCP-4 in THF. Finally, the three PPMC–PEG copolymers synthesized were found to adopt lyotropic cholesteric mesophases in concentrated toluene solutions (ca. 30 wt %).
We report here the self-assembly studies of 22 polycarbodiimides (PCDs) in complex morphologies such as fibers, looped fibers, fibrous networks, ribbons, worm-like aggregates, toroidal structures, ...and craters that were examined by combination of TMAFM, TEM, SEM, and powder XRD methods as well as semiempirical modeling. Morphology characterization in the thin film (TMAFM, TEM) and in bulk (SEM, pXRD) revealed the formation of fiber-like aggregates assembled from the bundles of individual helices. In certain cases superhelical motifs of both right- and left-handed screw senses were identified. It seemed likely that the great variety of morphologies observed is a result of extensive hydrophobic side chain/side chain interactions of the singular polycarbodiimide strands.
The methods of cyclic voltammetry, ESR electrolysis, and quantum chemical simulation were used to study the
tert
-butanol (
tert
-BuOH) oxidation mechanism in the presence of mediator cation radicals ...of pyrazine-di-N-oxide, 2,5-di-Me- and 2,3,5,6-tetra-Me-pyrazine-di-N-oxdides. This study was carried out on carbon glass (CG) and Pt electrodes in 0.1 M LiClO
4
solution in acetonitrile and on Au electrode in
tert
-butanol containing 0.05 M LiClO
4
. The ESR spectra of cation and anion radicals of aromatic di-N-oxides were recorded in
tert-
BuOH. The quantum chemical simulation of the reaction between pyrazine-di-N-oxide radical cation and C-H bond in
tert
-BuOH was performed. The results were explained in the terms of the general two-electron oxidation mechanism of
tert
-BuOH in the complex with aromatic di-N-oxide cation radical as mediator.
Atmospheric and water loss from early Venus Kulikov, Yu.N.; Lammer, H.; Lichtenegger, H.I.M. ...
Planetary and space science,
11/2006, Letnik:
54, Številka:
13
Journal Article
Recenzirano
Previous interpretations of the Pioneer Venus mass spectrometer data of the deuterium to hydrogen
(
D
/
H
)
ratio of
1.9
×
10
-
2
or
120
±
40
times the terrestrial value indicate that Venus may have ...had at least an
H
2
O
content of the order of about 0.3% of a terrestrial ocean (TO), and even much more during and shortly after the accretion period of
⩽
300
Myr
, depending on the unknown ratio of a continuous supply of
H
2
O
by comets to a hydrogen blow-off loss and impact erosion of the early atmosphere. In view of the low
H
2
O
abundance in the present atmosphere, several studies suggest that the planet should have lost most of its
H
2
O
during the early high X-ray, EUV and solar wind period of the active young Sun. Because oxygen did not accumulate in Venus’ atmosphere it is commonly believed that a part of the oxygen from dissociated
H
2
O
vapor was dragged off to space along with the escaping hydrogen during a blow-off period, or could have oxidized the surface minerals to produce FeO and
Fe
2
O
3
to the depths of a few kilometers to tens of kilometers depending on the initial amount of
H
2
O
. We use in the present study, for the first time, multi-wavelength X-ray and EUV (XUV) observations by the ASCA, ROSAT, EUVE, FUSE and IUE satellites and stellar winds inferred from mass loss observations by the Hubble Space Telescope of solar proxies with ages
<
4.6
Gyr
for the investigation of how efficiently the radiation and particle environment of the young Sun could have influenced the evolution of the early Venusian atmosphere and its
H
2
O
inventory due to the removal of oxygen picked up by the solar wind. For modelling the Venusian thermosphere over the planetary history we apply a diffusive-gravitational equilibrium and thermal balance model and investigate the heating of the early thermosphere by photodissociation and ionization processes, due to exothermic chemical reactions and cooling by
CO
2
IR emission in the
15
μ
m
band. Our model simulations result in expanded thermospheres with exobase levels between about 200
km at present and about 2200
km 4.5
Gyr ago. Moreover, our results yield high exospheric temperatures during the active phase of the young Sun even if we assume a “dry”
CO
2
atmosphere with similar composition that is observed on present Venus of more than 8000
K after the Sun arrived at the zero-age-main-sequence (ZAMS). Exospheric temperatures above about 4000
K lead to diffusion-limited escape and high loss rates for atomic hydrogen. The duration of this blow-off phase for atomic hydrogen essentially depends on the mixing ratios of
CO
2
,
N
2
and
H
2
O
in the early Venusian atmosphere and could last between about 150 to several hundred Myr, which could result in a large thermal loss of hydrogen from Venus. For studying how much of the
H
2
O
-related oxygen could have been lost to space by the ion pick up process due to the stronger solar wind and higher XUV fluxes of the young Sun we used our modelled atmospheric density profiles and studied the loss of
O
+
ion pick up from the upper atmosphere of Venus over the planet's history by applying a numerical test particle model. Depending on the used solar wind parameters, our model simulations show that ion pick up by a strong early solar wind on a non-magnetized Venus could erode during 4.6
Gyr more than about 250
bar of
O
+
ions, that corresponds to an equivalent amount of one terrestrial ocean. Finally, we discuss the implications of our findings for the formation of the Venusian atmosphere and discuss our results in the frame of previous studies.
We investigate the efficiency of the atmospheric mass loss due to hydrodynamic blow-off over the lifetime of the exoplanet HD209458b by studying numerically its hydrogen wind for host star X-ray and ...EUV (XUV) fluxes between 1 and 100 times that of the present Sun. We apply a time-dependent numerical algorithm which is able to solve the system of hydrodynamic equations straight through the transonic point of the flow including Roche lobe effects. The mass loss rates are calculated as functions of the absorbed energy in the thermosphere. Depending on the heating efficiency for a hydrogen-rich thermosphere the maximum temperature obtained in our study at
1.5
R
pl
by neglecting IR cooling is about 5000–10,000
K for heating efficiencies of 10% and 60%, respectively. We find that the upper atmosphere of HD209458b experiences hydrodynamic blow-off even at such low temperatures if one does not neglect gravitational effects caused by the proximity of the planet to its Roche lobe boundary. Depending on the heating efficiency, we find from the solution of the hydrodynamic equations of mass, momentum, and energy balance that energy-limited mass loss rate estimations overestimate the realistic mass loss rate at present time for HD209458b by several times. Using the maximum heating efficiency for hydrogen–rich atmospheres of 60% we find that HD209458b may experience an atmospheric mass loss rate at present time of about
3.5
×
10
10
g
s
-
1
. The mass loss rate evolves to higher values for higher XUV fluxes expected during the early period of the planet's host star evolution, reaching values of several times
10
12
g
s
-
1
. The integrated mass loss is found to be between 1.8% and 4.4% of the present mass of HD209458b. We found that the influence of the stellar tidal forces on atmospheric loss (the Roche lobe effect) is not significant at 0.045
AU. For a similar exoplanet, but at closer orbital distances
⩽
0.02
AU
, the combined effect of the Roche lobe and the high XUV radiation result in much higher thermal loss rates of about
2.6
×
10
11
g
s
-
1
and even more for early stages. This leads to a total loss over 4
Gyr of 27.5% of the planetary mass.
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