3,361 research outputs found
Rest-frame stacking of 2XMM catalog sources : Properties of the Fe Kalpha line
The aim of this work is to characterize the average Fe K emission properties
of active galactic nuclei (AGNs) in the source rest-frame. We selected a sample
of 248 AGNs from the 2XMM catalog, covering a wide redshift range 0 < z < 5 and
with the EPIC-PN net 2-10 keV rest-frame counts >=200 and power law photon
indices in the range 1.5-2.2. We employed two fully independent rest-frame
stacking procedures to compute the mean Fe K profile. The counting statistics
for the integrated spectrum is comparable to the one available for the best
studied local Seyferts. To identify the artifacts possibly introduced by the
stacking procedure, we have carried out simulations. We report that the average
Fe K line profile in our sample is best represented by a combination of a
narrow and a broad line. The equivalent widths of the narrow and broad
(parametrized with a diskline) components are ~30 eV and ~100 eV, respectively.
We also discuss the results of more complex fits and the implications of the
adopted continuum modeling on the broad line parameters and its detection
significance.Comment: 13 pages, 13 figures, Accepted for publication in A&
Role of Winged Helix Transcription Factor (WIN) in the Regulation of Sertoli Cell Differentiated Functions: WIN Acts as an Early Event Gene for Follicle-Stimulating Hormone
Members of the winged helix transcription factor family are known to regulate epithelial cell differentiation by regulating cell-specific gene expression. rWIN is a newly discovered member of the winged helix family shown to be present in the adult rat testis. In the testis the human homolog of rWIN, HFH-11, was localized to the germ cells (i.e. spermatocytes and spermatids) undergoing spermatogenesis. In the present study we show that rWIN is also expressed in testicular Sertoli cells. Sertoli cells are the epithelial component of the semi-niferous tubule and provide both the cytoarchitectural support and the microenvironment for developing germ cells. The presence of rWIN in Sertoli cells was confirmed by Northern blot and RT-PCR analysis. The rWIN transcript size in the Sertoli cells was different from the germ cell transcript that is probably due to alternative splicing or modifications of the 3-untranslated region. At least two spliced variants of rWIN were observed in the Sertoli cells corresponding to the deletion of an exon in the DNA-binding region. Long term stimulation of cultured Sertoli cells with the gonadotropin FSH down-regulated rWIN expression. In contrast, short-term stimulation (2 h) transiently up-regulated rWIN expression. The FSH-induced transient stimulation of rWIN precedes expression of the transferrin gene that is a marker of Sertoli cell differentiation. FSH-induced transferrin promoter activity was inhibited when cultured Sertoli cells were treated with an antisense oligonucleotide to rWIN. Interestingly , the constitutive overexpression of the DNA-binding domain of rWIN also down-regulated transferrin promoter activity. Analysis of the transferrin promoter with various deletion mutations suggested that rWIN acts at an upstream gene of the transferrin promoter. The results indicate that a transient up-regulation of rWIN in part mediates the ability of FSH to activate the transferrin promoter, which can be inhibited with a rWIN antisense oligonucleotide or constitutive expression of the rWIN DNA-binding domain. The current study demonstrates that rWIN acts as an early event gene for FSH actions on Sertoli cells and that rWIN appears to have a role in the regulation of Sertoli cell differentiated functions. (Endocrinology 141: 2758 –2766, 2000
Tillage and Mulching Effects on Crop Productivity and Moisture Dynamics in Fodder Sorghum Based Cropping Systems under Rainfed Condition
Indian farmers generally take more than one crop in a year to maximize their total production and profits. In this process fodder sorghum followed by crops like chickpea, wheat, oat, barley and mustard are common in Bundelkhand region of central India. The soils of Budelkhand region of India are medium to low in fertility with low organic matter content and poor water holding capacity that limits the fodder and food productivity. Therefore, adoption of resource conserving technologies in fodder sorghum based cropping systems under rainfed conditions is one of the potential areas, where increase in green fodder and food production with enhanced resource use efficiency can be achieved (Dixit et al., 2014). Adoption of resource conserving technologies includes minimal soil disturbance, maintaining soil cover and crop diversification through conservation of moisture for which the role of green manure mulches has been well recognised. Under rainfed situation, moisture stress has been identified as one of most important factor limiting yield of post rainy season crop. Introducing conservation tillage (zero tillage/reduced tillage) along with foliage mulching may improve soil moisture conservation, weed control, soil physic-chemical and biological properties, system productivity and may also reduce fuel, animal or human energy required for land preparation
A New Cosmological Model: Exploring the Evolution of the Universe and Unveiling Super-Accelerated Expansion
In this paper, we present a cosmological model designed to study the
evolution of the universe based on a new parametrization of the deceleration
parameter. The model considers a spatially flat, homogeneous, and isotropic
Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe filled with radiation,
dark matter (DM), and dark energy (DE). We derive the Friedmann equations and
the energy conservation equation for the universe, accounting for separate
conservation equations for radiation, DM, and DE. Our proposed deceleration
parameter is given by a formula involving constants , ,
, , , , and . which we
subsequently fit to observational data. To assess the model's viability, we
compare it with a diverse range of observational data, including cosmic
chronometers, type Ia supernovae, baryon acoustic oscillations, and cosmic
microwave background measurements. Employing the chi-square statistic and a
Markov Chain Monte Carlo (MCMC) method, we estimate the best-fit values for the
free parameters and investigate the constraints imposed by observational data
on the model. Our results indicate that our cosmological model provides an
excellent fit to the observed data and exhibits a remarkable agreement with the
standard CDM paradigm at higher redshifts. However, the most
intriguing discovery lies in the model's prediction of a super-accelerated
expansion in the distant future, in contrast to the de Sitter phase predicted
by CDM. This implies the presence of dark energy driving the
universe's accelerated expansion. These findings suggest that our proposed
cosmological model offers a compelling alternative to the CDM
paradigm, shedding new light on the nature of dark energy and the future fate
of the cosmos.Comment: 10 figures, 2 table
Mesonephric-like adenocarcinoma of the ovary with co-existent endometriosis: A case report and review of the literature
© 2020 The Authors Introduction: Mesonephric-like adenocarcinoma (MLA) is a rare malignant gynecologic neoplasm occurring in the uterine corpus and ovary. The morphological and immunohistochemical characteristics of MLA closely resemble that of cervical mesonephric adenocarcinomas, but whether they share a common histogenesis remains unclear. Two main theories for histogenesis of MLAs include the origination of these neoplasms from mesonephric remnants, as is the case for cervical mesonephric adenocarcinoma, versus the differentiation along a mesonephric pathway from Mullerian lesions. Case: A 67-year-old presented after a right salpingo-oophorectomy for a complex ovarian mass revealed a mesonephric-like adenocarcinoma of the ovary and endometriosis. She underwent a total abdominal hysterectomy, pelvic lymphadenectomy, and infra-colic omentectomy, and diagnosed with Stage IA mesonephric-like adenocarcinoma of the ovary. At 18 months post-operatively, the patient developed flank and abdominal pain and was found to have multiple sites of recurrent disease. She was referred to medical oncology for chemotherapy as she was not a candidate for surgical cytoreduction. Discussion: This case demonstrates the aggressive nature of ovarian MLA and the need for a multidisciplinary approach when determining the treatment. In addition, this case provides further evidence to support the theory that at least a subset of MLAs arises from a Mullerian lesion which then differentiates down a mesonephric pathway
Analyzing a higher order model and its implications in the late evolution of the Universe using recent observational datasets
In this research paper, we explore a well-motivated parametrization of the
time-dependent deceleration parameter, characterized by a cubic form, within
the context of late time cosmic acceleration. The current analysis is based on
the gravity theory, by considering the background metric as the
homogeneous and isotropic Friedmann Lema\^itre Robertson Walker (FLRW) metric.
Investigating the model reveals intriguing features of the late universe. To
constrain the model, we use the recent observational datasets, including cosmic
chronometer (CC), Supernovae (SNIa), Baryon Acoustic Oscillation (BAO), Cosmic
Microwave Background Radiation (CMB), Gamma Ray Burst (GRB), and Quasar (Q)
datasets. The joint analysis of these datasets results in tighter constraints
for the model parameters, enabling us to discuss both the physical and
geometrical aspects of the model. Moreover, we determine the present values of
the deceleration parameter (), the Hubble parameter (), and the
transition redshift () from deceleration to acceleration ensuring
consistency with some recent results of Planck 2018. Our statistical analysis
yields highly improved results, surpassing those obtained in previous
investigations. Overall, this study presents valuable insights into the higher
order model and its implications for late-time cosmic acceleration,
shedding light on the nature of the late universe
A rapid method of cloning functional variable-region antibody genes in Escherichia coli as single-chain immunotoxins
We have devised a strategy based on polymerase chain reaction (PCR) for the rapid cloning of functional antibody genes as single-chain immunotoxins. RNA from a hybridoma producing an antibody (OVB3) that reacts with ovarian cancer cells was used as a template to make the first strand of a cDNA. Then a second strand was synthesized and amplified by using two sets of DNA primers that (i) hybridized to the ends of the light- and heavy-chain variable regions, (ii) encoded a linker peptide, and (iii) contained appropriate restriction enzyme sites for cloning. After 30 cycles of PCR, the DNA fragments containing sequences encoding the light- and heavy-chain variable regions were cloned into an Escherichia coli expression vector containing a portion of the Pseudomonas exotoxin gene. Clones encoding recombinant single-chain immunotoxins were expressed in E. coli and the protein product was assessed for its ability to bind to or kill cells bearing the OVB3 antigen. By using this approach it should be possible to rapidly clone the functional variable region sequences of many different antibodies from hybridoma RNA
Collapse dynamics of a - Bose-Einstein condensate
In this paper, we present a theoretical study of a two-component
Bose-Einstein condensate composed of Ytterbium (Yb) isotopes in a three
dimensional anisotropic harmonic potential. The condensate consists of a
mixture of atoms which have a negative s-wave scattering
length and atoms having a positive s-wave scattering
length. We study the ground state as well as dynamic properties of this
two-component condensate. Due to the attractive interactions between
atoms, the condensate of undergo a
collapse when the particle number exceed a critical value. The critical number
and the collapse dynamics are modified due to the presence of
atoms. We use coupled two-component Gross-Pitaevskii
equations to study the collapse dynamics. The theoretical results obtained are
in reasonable agreement with the experimental results of Fukuhara {\em et al.}
[PRA{\bf 79}, 021601(R) (2009)].Comment: 6 pages, 5 figure
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