105 research outputs found
2,4-Dihydroxy-N′-(4-methoxybenzylidene)benzohydrazide
The molecule of the title compound, C15H14N2O4, displays a trans configuration with respect to the hydrazide C=N bond. The dihedral angle between the two benzene rings is 15.0 (2)°. In the crystal structure, molecules are linked through intermolecular O—H⋯N and O—H⋯O hydrogen bonds, forming layers parallel to the ab plane; an intramolecular N—H⋯O hydrogen bond is also present
A novel DEAH-box helicase 37 mutation associated with differences of sex development
ObjectiveTo determine the genetic etiology of a family pedigree with two patients affected by differences of sex development (DSD).MethodsAssess the clinical characteristics of the patients and achieve exome sequencing results and in vitro functional studies.ResultsThe 15-year-old proband, raised as female, presented with delayed puberty and short stature associated with atypical genitalia. Hormonal profile showed hypergonadotrophic hypogonadism. Imaging studies revealed the absence of a uterus and ovaries. The karyotype confirmed a 46, XY pattern. Her younger brother presented with a micropenis and hypoplastic scrotum with non-palpable testis and hypospadias. Laparoscopic exploration was performed on the younger brother. Streak gonads were found and removed due to the risk of neoplastic transformation. Post-operative histopathology showed the co-existence of Wolffian and Müllerian derivatives. Whole-exome sequencing identified a novel mutation (c.1223C>T, p. Ser408Leu) in the Asp-Glu-Ala-His-box helicase 37 gene, which was found to be deleterious by in silico analysis. Segregation analysis of the variant displayed a sex-limited, autosomal dominant, maternal inheritance pattern. In vitro experiments revealed that the substitution of 408Ser by Leu caused decreased DHX37 expression both at the mRNA and protein levels. Moreover, the β-catenin protein was upregulated, and the p53 protein was unaltered by mutant DHX37.ConclusionsWe described a novel mutation (c.1223C>T, p. Ser408Leu) of the DHX37 gene associated with a Chinese pedigree consisting of two 46, XY DSD patients. We speculated that the underlying molecular mechanism might involve upregulation of the β-catenin protein
A multi band study of the optically dark GRB 051028
Observations were made of the optical afterglow of GRB 051028 with the Lulin
observatory's 1.0 m telescope and the WIDGET robotic telescope system. R band
photometric data points were obtained on 2005 October 28 (UT), or 0.095-0.180
days after the burst. There is a possible plateau in the optical light curve
around 0.1 days after the burst; the light curve resembles optically bright
afterglows (e.g. GRB 041006, GRB 050319, GRB060605) in shape of the light curve
but not in brightness. The brightness of the GRB 051028 afterglow is 3
magnitudes fainter than that of one of the dark events, GRB 020124. Optically
dark GRBs have been attributed to dust extinction within the host galaxy or
high redshift. However, the spectrum analysis of the X-rays implies that there
is no significant absorption by the host galaxy. Furthermore, according to the
model theoretical calculation of the Ly absorption to find the limit of
GRB 051028's redshift, the expected band absorption is not high enough to
explain the darkness of the afterglow. While the present results disfavor
either the high-redshift hypothesis or the high extinction scenario for
optically dark bursts, they are consistent with the possibility that the
brightness of the optical afterglow, intrinsically dark.Comment: 5page, 5 figures, 1 table, accepted for publication in PASJ Letter.
PASJ styl
Probing the nature of high- z short GRB 090426 with its early optical and X-ray afterglows
GRB 090426 is a short-duration burst detected by Swift ( s in the observer frame and s in the burst frame at z = 2.609 ). Its host galaxy properties and some gamma-ray-related correlations are analogous to those seen in long-duration gamma-ray bursts (GRBs), which are believed to be of a massive star origin (so-called Type II GRBs). We present the results of its early optical observations with the 0.8-m Tsinghua University–National Astronomical Observatory of China Telescope (TNT) at Xinglong Observatory and the 1-m LOAO telescope at Mt Lemmon Optical Astronomy Observatory in Arizona. Our well-sampled optical afterglow light curve covers from to 10 4 s after the GRB trigger. It shows two shallow decay episodes that are likely due to energy injection, which end at and 7100 s, respectively. The decay slopes after the injection phases are consistent with each other ( ). The X-ray afterglow light curve appears to trace the optical, although the second energy-injection phase was missed due to visibility constraints introduced by the Swift orbit. The X-ray spectral index is without temporal evolution. Its decay slope is consistent with the prediction of the forward shock model. Both X-ray and optical emission are consistent with being in the same spectral regime above the cooling frequency ( ). The fact that is below the optical band from the very early epoch of the observation provides a constraint on the burst environment, which is similar to that seen in classical long-duration GRBs. We therefore suggest that death of a massive star is the possible progenitor of this short burst.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79209/1/j.1365-2966.2010.17419.x.pd
Probing the Nature of High-z Short GRB 090426 with Its Early Optical and X-ray Afterglows
GRB 090426 is a short duration burst detected by Swift ( s
in the observer frame, and s in the burst frame at
). Its host galaxy properties and some -ray related
correlations are analogous to those seen in long duration GRBs, which are
believed to be of a massive-star origin (so-called Type II GRBs). We present
the results of its early optical observations with the 0.8-m TNT telescope at
Xinglong observatory, and the 1-m LOAO telescope at Mt. Lemmon Optical
Astronomy Observatory in Arizona. Our well-sampled optical afterglow lightcurve
covers from seconds to seconds post the GRB trigger. It
shows two shallow decay episodes that are likely due to energy injection, which
end at seconds and seconds, respectively. The decay
slopes post the injection phases are consistent with each other (). The X-ray afterglow lightcurve appears to trace the optical, although
the second energy injection phase was missed due to visibility constraints
introduced by the {\em Swift} orbit. The X-ray spectral index is without temporal evolution. Its decay slope is consistent with the
prediction of the forward shock model. Both X-ray and optical emission is
consistent with being in the same spectral regime above the cooling frequency
(). The fact that is below the optical band from the very early
epoch of the observation provides a constraint on the burst environment, which
is similar to that seen in classical long duration GRBs. We therefore suggest
that death of a massive star is the possible progenitor of this short burst.Comment: 7 pages, 1 figures, 2 tables, revised version, MNRAS, in pres
- …