308 research outputs found
Features of verbal communication of the Tajik youth in social networks
Within the framework of this article, the author presents materials of empirical research on the features of verbal communication of Tajik youth in social networks. Data of content analysis is given. The author of the article comes to the conclusion that the written speech of the Tajik users of social networks is different. Written speech of Tajik users of networks in their native language is diverse, in Russian it is simple, monotonous
Time-dependent Density Functional calculation of e-H scattering
Phase shifts for single-channel elastic electron-atom scattering are derived
from time-dependent density functional theory. The H ion is placed in a
spherical box, its discrete spectrum found, and phase shifts deduced.
Exact-exchange yields an excellent approximation to the ground-state Kohn-Sham
potential, while the adiabatic local density approximation yields good singlet
and triplet phase shifts.Comment: 5 pages, 4 figures, 1 tabl
Effects of Light-at-Night on the Rat Liver - A Role for the Autonomic Nervous System
Exposure to light at night (LAN) has been associated with serious pathologies, including obesity, diabetes and cancer. Recently we showed that 2 h of LAN impaired glucose tolerance in rats. Several studies have suggested that the autonomic nervous system (ANS) plays an important role in communicating these acute effects of LAN to the periphery. Here, we investigated the acute effects of LAN on the liver transcriptome of male Wistar rats. Expression levels of individual genes were not markedly affected by LAN, nevertheless pathway analysis revealed clustered changes in a number of endocrine pathways. Subsequently, we used selective hepatic denervations [sympathetic (Sx), parasympathetic (Px), total (Tx, i.e., Sx plus Px), sham] to investigate the involvement of the ANS in the effects observed. Surgical removal of the sympathetic or parasympathetic hepatic branches of the ANS resulted in many, but small changes in the liver transcriptome, including a pathway involved with circadian clock regulation, but it clearly separated the four denervation groups. On the other hand, analysis of the liver metabolome was not able to separate the denervation groups, and only 6 out of 78 metabolites were significantly up- or downregulated after denervations. Finally, removal of the sympathetic and parasympathetic hepatic nerves combined with LAN exposure clearly modulated the effects of LAN on the liver transcriptome, but left most endocrine pathways unaffected. Conclusion: One-hour light-at-night acutely affects the liver transcriptome. Part of this effect is mediated via the nervous innervation, as a hepatectomy modulated and reduced the effect of LAN on liver transcripts
Two-pion exchange and strong form-factors in covariant field theories
In this work improvements to the application of the Gross equation to nuclear
systems are tested. In particular we evaluate the two pion exchange diagrams,
including the crossed-box diagram, using models developed within the
spectator-on-mass-shell covariant formalism. We found that the form factors
used in these models induce spurious contributions that violate the unitary cut
requirement. We tested then some alternative form-factors in order to preserve
the unitarity condition. With this new choice, the difference between the exact
and the spectator-on-mass-shell amplitudes is of the order of the one boson
scalar exchange, supporting the idea that this difference may be parameterized
by this type of terms.Comment: RevTeX, 21 pages, 19 figures (PostScript
Polarization transfer observables for quasielastic proton-nucleus scattering in terms of a complete Lorentz invariant representation of the NN scattering matrix
For the calculation of polarization transfer observables for quasielastic
scattering of protons on nuclei, a formalism in the context of the Relativistic
Plane Wave Impulse Approximation is developed, in which the interaction matrix
is expanded in terms of a complete set of 44 independent invariant amplitudes.
A boson-exchange model is used to predict the 39 amplitudes which were omitted
in the formerly used five-term parameterization(the SPVAT form) of the
nucleon-nucleon scattering matrix. Use of the complete set of amplitudes
eliminates the arbitrariness of the five-term representation.Comment: 29 pages, 2 figure
The influence of repeated injections on pharmacokinetics and biodistribution of different types of sterically stabilized immunoliposomes
AbstractSterically stabilized immunoliposomes (IL) with diameters of about 135 nm carrying mouse IgG, either coupled directly to the liposome surface, or linked to the terminal ends of grafted poly(ethylene glycol) (PEG) chains by a recently described conjugation procedure (Cyanur-PEG-PE), were intravenously injected into rats and the elimination kinetics and biodistribution were determined and compared with control liposomes. The amounts of conjugated antibodies were about 30 μg/μmol total lipid for all IL. In naive rats, plain pegylated liposomes displayed the longest blood circulation time, whereas the terminal-coupled IL exhibited the fastest elimination. Liposomes containing the underivatized anchor molecules circulate nearly as long as plain pegylated liposomes, indicating that the fast elimination of the IL can be attributed to the presence of antibodies.A second injection of identical liposomes 14 days after the first injection had a considerable influence on the pharmacokinetic parameters of the liposomes. The circulation time of plain pegylated liposomes drastically dropped by half and their uptake by the liver increased concomitantly, indicating that the PEG, upon repeated injection, ceases to function as an efficient barrier reducing opsonization and/or immune reactions. The circulation time of conventional IL was moderately reduced upon a second injection, whereas that of the terminally coupled IL was nearly unaffected. These differences among the IL demonstrate that the pharmacokinetic behavior of IL is strongly dependent on the antibody conjugation site on the liposome. The observed effects of repeated injections were similar for liposomes of 90-nm diameter. The phenomena described may have important implications for the repeated application of IL as drug carriers
Mass spectrometric quantification of urinary 6-sulfatoxymelatonin:age-dependent excretion and biological variation
Objectives: Regulators of circadian rhythm, including melatonin, influence fundamental biological processes. Measuring the melatonin metabolite 6-sulfatoxymelatonin in urine can estimate melatonin production. 6-sulfatoxymelatonin is mainly analyzed by immunoassays, but these methods are hampered by cross-reactivity and poor reproducibility when used to analyze small molecules. Therefore, we validated a high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify 6-sulfatoxymelatonin in urine. We evaluated age-dependent 24-h excretion of 6-sulfatoxymelatonin into urine and the biological variation of urinary excretion in healthy individuals. Methods: The online solid phase extraction method combined with LC-MS/MS was validated according to international guidelines, and used to measure the excretion of 6-sulfatoxymelatonin into urine of 240 healthy individuals. Biological variation of 6-sulfatoxymelatonin excretion was examined in 10 healthy individuals. Results: Urinary 6-sulfatoxymelatonin results were well within the validation criteria (interassay coefficient of variation: Conclusions: This MS-based method enables straightforward, reproducible, and sensitive quantification of 6-sulfatoxymelatonin in urine. Urinary 6-sulfatoxymelatonin levels decreased with age. Biological variation of 6-sulfatoxymelatonin excretion into urine was high between subjects and lower within subjects, indicating that repeated measurements of 6-sulfatoxymelatonin in 24-h urine are needed in future studies
Two-pion exchange potential and the amplitude
We discuss the two-pion exchange potential which emerges from a box diagram
with one nucleon (the spectator) restricted to its mass shell, and the other
nucleon line replaced by a subtracted, covariant scattering amplitude
which includes , Roper, and isobars, as well as contact terms
and off-shell (non-pole) dressed nucleon terms. The amplitude satisfies
chiral symmetry constraints and fits data below 700 MeV pion
energy. We find that this TPE potential can be well approximated by the
exchange of an effective sigma and delta meson, with parameters close to the
ones used in one-boson-exchange models that fit data below the pion
production threshold.Comment: 9 pages (RevTex) and 7 postscript figures, in one uuencoded gzipped
tar fil
The Effect of Tryptophan 2,3-Dioxygenase Inhibition on Kynurenine Metabolism and Cognitive Function in the APP23 Mouse Model of Alzheimer's Disease
Alzheimer's disease (AD) is associated with progressive endogenous neurotoxicity and hampered inflammatory regulation. The kynurenine (Kyn) pathway, which is controlled by tryptophan 2,3-dioxygenase (TDO), produces neuroactive and anti-inflammatory metabolites. Age-related Kyn pathway activation might contribute to AD pathology in humans, and inhibition of TDO was found to reduce AD-related cellular toxicity and behavioral deficits in animal models. To further explore the effect of aging on the Kyn pathway in the context of AD, we analyzed Kyn metabolite profiles in serum and brain tissue of the APP23 amyloidosis mouse model. We found that aging had genotype-independent effects on Kyn metabolite profiles in serum, cortex, hippocampus and cerebellum, whereas serum concentrations of many Kyn metabolites were reduced in APP23 mice. Next, to further establish the role of TDO in AD-related behavioral deficits, we investigated the effect of long-term pharmacological TDO inhibition on cognitive performance in APP23 mice. Our results indicated that TDO inhibition reversed recognition memory deficits without producing measurable changes in cerebral Kyn metabolites. TDO inhibition did not affect spatial learning and memory or anxiety-related behavior. These data indicate that age-related Kyn pathway activation is not specific for humans and could represent a cross-species phenotype of aging. These data warrant further investigation on the role of peripheral Kyn pathway disturbances and cerebral TDO activity in AD pathophysiology
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