141 research outputs found
Conservation of wild silkworm genetic resources through cryopreservation: Standardization of sperm processing
Conservation of the invaluable sericigenous genetic resources is of prime importance with respect to their utilization and improvement for wider exploitation. Conservation of wild silkworms and its applicability in hybridization have limitations due to incompatibility, less amenability, change of behaviour under ex situ conditions, non-synchronization of moth eclosion and difficulties in mating between variables. In view of this, the newer technologies such as cryopreservation and artificial insemination are offering better strategies for preservation of biologically active samples like semen at sub-zero temperature (-196Âș C) conditions for longer duration. In this context, under standardization of sperms preservation from wild silkworms, two methods of semen collection were scrutinized for obtaining active and viable sperm for cryopreservation and further artificial insemination. Semen collection from the seminal vesicle of freshly emerged male moth and the other from the bursa copulatrix (BC) and spermatheca of the female moth after mating. The sperms in the semen collected from seminal vesicle are in the form of bundles known as eupyrene sperm bundles and apyrene sperms. The morphology and behaviour of these sperm bundles were recorded through microscopic examination. To study the density and motility behaviour of the sperms, sperm bundles were treated with proteolytic enzyme (~2-3”g/ml) to digest the membrane and release the sperms. The density and motility behaviour of sperms in the semen recovered from the BC and spermatheca of female moth after mating were higher compared to those released after digestion of sperm bundles from seminal vesicle of the male moth
Primary Amoebic (Naegleria fowleri) Meningoencephalitis Presenting as Status Epilepticus
Primary amebic meningoencephalitis (PAM) is a rare entity. Usual presenting features are fever, headache and seizures with meningeal signs and this disease carries high mortality rate. We present a case report of PAM presenting as status epilepticus
The validity of 21 cm spin temperature as a kinetic temperature indicator in atomic and molecular gas
The gas kinetic temperature () of various interstellar environments is
often inferred from observations that can deduce level populations of atoms,
ions, or molecules using spectral line observations; H I 21 cm is perhaps the
most widely used with a long history. Usually the H I 21 cm line is assumed to
be in thermal equilibrium and the populations are given by the Boltzmann
distribution. A variety of processes, many involving Lyman alpha (),
can affect the 21 cm line. Here we show how this is treated in the spectral
simulation code Cloudy, and present numerical simulations of environments where
this temperature indicator is used, with a detailed treatment of the physical
processes that determine level populations within . We discuss situations
where this temperature indicator traces , cases where they fail, as well
as the effects of pumping on the 21 cm spin temperature. We also
show that the excitation temperature rarely traces the gas kinetic
temperature.Comment: Accepted for publication in Ap
A recent update of gas-phase chemical reactions and molecular lines in CLOUDY: its effects on millimeter and sub-millimeter molecular line predictions
Here we present our current updates of the gas-phase chemical reaction rates
and molecular lines in the spectral synthesis code CLOUDY, and its implications
in spectroscopic modelling of various astrophysical environments. We include
energy levels, radiative and collisional rates for HF, CF, HCN,
ArH, HCl, HCN, CN, CH, and CH. Simultaneously, we expand our molecular
network involving these molecules. For this purpose, we have added 561 new
reactions and have updated the existing 165 molecular reaction rates involving
these molecules. As a result, CLOUDY now predicts all the lines arising from
these nine molecules. In addition, we also update H--H collisional data
up to rotational levels =31 for =0. We demonstrate spectroscopic
simulations of these molecules for a few astrophysical environments. Our
existing model for globules in the Crab nebula successfully predicts the
observed column density of ArH. Our model predicts a detectable amount of
HeH, OH, and CH for the Crab nebula. We also model the ISM towards
HD185418, W31C, NGC 253, and our predictions match with most of the observed
column densities within the observed error bars. Very often molecular lines
trace various physical conditions. Hence, this update will be very supportive
for spectroscopic modelling of various astrophysical environments, particularly
involving sub-millimeter and mid-infrared observations using ALMA and JWST,
respectively.Comment: 40 pages, 6 figures, 18 tables, Accepted for publication in Ap
Physical conditions in the ISM towards HD185418
We have developed a complete model of the hydrogen molecule as part of the
spectral simulation code Cloudy. Our goal is to apply this to spectra of
high-redshift star-forming regions where H2 absorption is seen, but where few
other details are known, to understand its implication for star formation. The
microphysics of H2 is intricate, and it is important to validate these
numerical simulations in better-understood environments. This paper studies a
well-defined line-of-sight through the Galactic interstellar medium (ISM) as a
test of the microphysics and methods we use. We present a self-consistent
calculation of the observed absorption-line spectrum to derive the physical
conditions in the ISM towards HD185418, a line-of-sight with many observables.
We deduce density, temperature, local radiation field, cosmic ray ionization
rate, chemical composition and compare these conclusions with conditions
deduced from analytical calculations. We find a higher density, similar
abundances, and require a cosmic ray flux enhanced over the Galactic background
value, consistent with enhancements predicted by MHD simulations.Comment: 31 pages, accepted for publication in Ap
Histone deacetylase 1 and 2 drive differentiation and fusion of progenitor cells in human placental trophoblasts
Cell fusion occurs when several cells combine to form a multinuclear aggregate (syncytium). In human placenta, a syncytialized trophoblast (syncytiotrophoblast) layer forms the primary interface between maternal and fetal tissue, facilitates nutrient and gas exchange, and produces hormones vital for pregnancy. Syncytiotrophoblast development occurs by differentiation of underlying progenitor cells called cytotrophoblasts, which then fuse into the syncytiotrophoblast layer. Differentiation is associated with chromatin remodeling and specific changes in gene expression mediated, at least in part, by histone acetylation. However, the epigenetic regulation of human cytotrophoblast differentiation and fusion is poorly understood. In this study, we found that human syncytiotrophoblast development was associated with deacetylation of multiple core histone residues. Chromatin immunoprecipitation sequencing revealed chromosomal regions that exhibit dynamic alterations in histone H3 acetylation during differentiation. These include regions containing genes classically associated with cytotrophoblast differentiation (TEAD4, TP63, OVOL1, CGB), as well as near genes with novel regulatory roles in trophoblast development and function, such as LHX4 and SYDE1. Prevention of histone deacetylation using both pharmacological and genetic approaches inhibited trophoblast fusion, supporting a critical role of this process for trophoblast differentiation. Finally, we identified the histone deacetylases (HDACs) HDAC1 and HDAC2 as the critical mediators driving cytotrophoblast differentiation. Collectively, these findings provide novel insights into the epigenetic mechanisms underlying trophoblast fusion during human placental development
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