109 research outputs found
Comorbidity and syntropy of benign proliferative diseases of the female reproductive system: non-genetic, genetic, and epigenetic factors (review)
To establish common risk factors for the development of benign proliferative diseases of the female reproductive system (endometriosis, endometrial hyperplasia, and uterine leiomyoma
Relation Between the Thickness of Stellar Disks and the Relative Mass of Dark Halo in Galaxies
We consider a thickness of stellar disks of late-type galaxies by analyzing
the R and K_s band photometric profiles for two independent samples of edge-on
galaxies. The main goal is to verify a hypotesis that a thickness of old
stellar disks is related to the relative masses of the spherical and disk
components of galaxies. We confirm that the radial-to-vertical scale length
ratio for galactic disks increases (the disks become thinner) with the
increasing of total mass-to-light ratio of the galaxies, which characterize the
contribution of dark halo to the total mass, and with the decreasing of central
deprojected disk brightness (surface density). Our results are in good
agreement with numerical models of collisionless disks evolved from subcritical
velocity dispersion state to a marginally stable equilibrium state. This
suggests that in most galaxies the vertical stellar velocity dispersion, which
determine the equilibrium disk thickness, is close to the minimum value, that
ensures disk stability. The thinnest edge-on disks appear to be low brightness
galaxies (after deprojection) in which a dark halo mass far exceeds a mass of
the stellar disk.Comment: 13 pages. To be Published in Astronomy Letters, v.28(2002
Inner Polar Rings and Disks: Observed Properties
A list of galaxies with inner regions revealing polar (or strongly inclined
to the main galactic plane) disks and rings is compiled from the literature
data. The list contains 47 galaxies of all morphological types, from E to Irr.
We consider the statistics of the parameters of polar structures known from
observations. The radii of the majority of them do not exceed 1.5 kpc. The
polar structures are equally common in barred and unbarred galaxies. At the
same time, if a galaxy has a bar (or a triaxial bulge), this leads to the polar
disk stabilization - its axis of rotation usually coincides with the major axis
of the bar. More than two thirds of all considered galaxies reveal one or
another sign of recent interaction or merging. This fact indicates a direct
relation between the external environment and the presence of an inner polar
structure.Comment: 12 pages, 3 figures, accepted to Astrophysical Bulletin. Minor
changes and corrections are still possibl
Genetic signs of multiple colonization events in Baltic ciscoes with radiation into sympatric spring- and autumn-spawners confined to early postglacial arrival
Presence of sympatric populations may reflect local diversification or secondary contact of already distinct forms. The Baltic cisco (Coregonus albula) normally spawns in late autumn, but in a few lakes in Northern Europe sympatric autumn and spring- or winter-spawners have been described. So far, the evolutionary relationships and taxonomic status of these main life history forms have remained largely unclear. With microsatellites and mtDNA sequences, we analyzed extant and extinct spring- and autumn-spawners from a total of 23 Swedish localities, including sympatric populations. Published sequences from Baltic ciscoes in Germany and Finland, and Coregonus sardinella from North America were also included together with novel mtDNA sequences from Siberian C.sardinella. A clear genetic structure within Sweden was found that included two population assemblages markedly differentiated at microsatellites and apparently fixed for mtDNA haplotypes from two distinct clades. All sympatric Swedish populations belonged to the same assemblage, suggesting parallel evolution of spring-spawning rather than secondary contact. The pattern observed further suggests that postglacial immigration to Northern Europe occurred from at least two different refugia. Previous results showing that mtDNA in Baltic cisco is paraphyletic with respect to North American C.sardinella were confirmed. However, the inclusion of Siberian C.sardinella revealed a more complicated pattern, as these novel haplotypes were found within one of the two main C.albula clades and were clearly distinct from those in North American C.sardinella. The evolutionary history of Northern Hemisphere ciscoes thus seems to be more complex than previously recognized
Pathogenetic role of tumor necrosis factor (TNF-α) for the development of peritoneal tuberculosis in an experiment
Currently tuberculosis is considered as a group of diseases united by one etiological factor. The pathogenesis of certain localizations of tuberculous inflammation, in particular peritoneum tuberculosis, hasn’t been sufficiently studied. The role of cytokine mechanisms in the development of the disease and the elaboration of non-sterile immunity requires further experimental studies, in particular the creation of a reproducible model on laboratory animals.The aim: to study the effect of TNF-α on the development of tuberculosis of the serous coat of the abdominal cavity, as well as to evaluate the possibility of modeling tuberculous peritonitis in laboratory animals using infliximab.Materials and methods. The studies were conducted on 18 male rabbits, which were simulated peritoneal tuberculosis by intra-abdominal administration of a suspension of Mycobacterium tuberculosis. 10 rabbits of the experimental group were intravenously injected with an infliximab solution and an iron (III) hydroxide sucrose complex intraperitoneally a day before infection.Results. In the control group of animals, tuberculosis either didn’t develop, or in a third of cases it affected only the pulmonary parenchyma, while proliferative processes prevailed. On the contrary, in animals with inactivated TNF-α, in 100 % of observations, tuberculous peritonitis was detected with associated lung damage and the predominance of alterative caseous processes.Conclusion. The created model of tuberculous peritonitis shows the leading role of TNF-α in the activation of macrophages, as well as in attracting cells to the site of infection. This is the primary signal necessary for the formation and stability of granulomas since the neutralization of this cytokine leads to a loss of control over the infection and the destruction of the granuloma with the development of destructive tuberculosis in the serous coat of the abdominal cavity
Collimation of a Circulating Beam in the U_70 Synchrotron by Use of Reflections in Axially - Oriented Crystals
The possibilities of the extraction and collimation of a circulating beam by
a new method due to the reflection of particles in crystals with axial
orientation were experimentally investigated in the Fall-2010 run at the U_70
synchrotron. Such crystals have positive features, because the axial potential
is five times larger than the planar potential. It has been shown that the
collimation efficiency can reach 90% due to axial effects in the crystal.
Losses of the circulating beam on a collimator have been reduced by several
times; this makes it possible to suppress the muon jet near the steel
collimator of the circulating beam.Comment: 6 pages, 7 figure
Способ моделирования специфического туберкулезного перитонита (экспериментальное исследование)
The objective: to create a reproducible model of chronic tuberculosis peritonitis to study pathophysiological mechanisms of its progression and to develop pathogenetically based therapy.Subjects and Methods. The study was performed using 10 male rabbits of the Chinchilla breed. The animals were administered intraperitoneal culture of Mycobacterium tuberculosis, tuberculosis peritonitis modeling was performed according to the proposed method.Results. In the course of the experiment, it was proved that all animals developed tuberculous peritonitis with lesions of the large omentum and serous integuments of internal organs. Molecular genetic tests of fragments of the omentum and peritoneum detected DNA of Mycobacterium tuberculosis.Цель исследования: создание воспроизводимой модели хронического туберкулезного перитонита для изучения патофизиологических механизмов его развития и использования в разработках по диагностике и лечению.Материалы и методы. Исследование выполнено с использованием 10 кроликов-самцов породы советская шиншилла. Животным выполняли внутрибрюшное введение культуры микобактерий туберкулеза, моделирование туберкулезного перитонита по предложенной нами методике.Результаты. В эксперименте доказано, что у всех животных развивался туберкулезный перитонит с поражением большого сальника и серозных покровов внутренних органов. При молекулярно-генетическом исследовании фрагментов сальника и брюшины выявлена ДНК микобактерий туберкулеза
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