1,498 research outputs found
Wind Variability in BZ Camelopardalis
(Shortened) Sequences of spectra of the nova-like cataclysmic variable (CV)
BZ Cam were acquired on 9 nights in 2005-2006 in order to study the time
development of episodes of wind activity known to occur frequently in this
star. We confirm past results that the P-Cygni absorption components of the
lines mostly evolve from a higher expansion velocity to lower velocity as an
episode progresses. We also commonly find blueshifted emission components in
the Halpha line profile, whose velocities and durations strongly suggest that
they are also due to the wind. We suggest that the progression from larger to
smaller expansion velocities is due the higher velocity portions of a wind
concentration moving beyond the edge of the continuum light of the disk first,
leaving a net redward shift of the remaining absorption profile. We also derive
a new orbital ephemeris for BZ Cam, using the radial velocity of the core of
the HeI 5876AA line, finding P = 0.15353(4). Using this period the wind
episodes in BZ Cam are found to be concentrated near inferior conjuction of the
emission line source. This result confirms that the winds in nova-like CVs are
often phase dependent, in spite of the puzzling implication that such winds
lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an
initial boost by acting on gas that has been lifted above the disk by the
interaction of the accretion stream with the disk, thereby imposing flickering
time scales onto the wind events, as well as leading to an orbital modulation
of the wind due to the non-axisymmetric nature of the stream/disk interaction.Comment: The Astronomical Journal, in pres
Inhibition of the Redox Function of APE1/Ref-1 in Myeloid Leukemia Cell Lines Results in a Hypersensitive Response to Retinoic Acid-induced Differentiation and Apoptosis
Objective
The standard of care for promyelocytic leukemia includes use of the differentiating agent all-trans retinoic acid (RA) and chemotherapy. RA induces cell differentiation through retinoic acid receptor (RAR) transcription factors. Because redox mechanisms influence how readily transcription factors bind to DNA response elements (RARE), the impact of small molecule (E3330) inhibition of the redox regulatory protein, apurinic-apyrimidinic endonuclease/redox effector factor (APE1/Ref-1) on RAR DNA binding and function in RA-induced myeloid leukemia cell differentiation and apoptosis was investigated.
Materials and Methods
The redox function of APE1 was studied using the small molecule inhibitor E3330 in HL-60 and PLB acute myeloid leukemia cells. Electrophoretic mobility shift assays were employed to determine effect of inhibitor on APE1/Ref-1 redox signaling function. Trypan blue assays, Annexin-V/propidium iodide and CD11b staining, and real-time polymerase chain reaction analyses were employed to determine survival, apoptosis, and differentiation status of cells in culture.
Results
RARα binds to its RARE in a redox-dependent manner mediated by APE1/Ref-1 redox regulation. Redox-dependent RAR-RARE binding is blocked by E3330, a small molecule redox inhibitor of APE1/Ref-1. Combination treatment of RA + E3330 results in a profound hypersensitivity of myeloid leukemia cells to RA-induced differentiation and apoptosis. Additionally, redox inhibition by E3330 results in enhanced RAR target gene, BLR-1, expression in myeloid leukemia cells.
Conclusions
The redox function of APE1/Ref-1 regulates RAR binding to its DNA RAREs influencing the response of myeloid leukemia cells to RA-induced differentiation. Targeting of APE1/Ref-1 redox function may allow manipulation of the retinoid response with therapeutic implications
Image and information management system
A system and methods through which pictorial views of an object's configuration, arranged in a hierarchical fashion, are navigated by a person to establish a visual context within the configuration. The visual context is automatically translated by the system into a set of search parameters driving retrieval of structured data and content (images, documents, multimedia, etc.) associated with the specific context. The system places ''hot spots'', or actionable regions, on various portions of the pictorials representing the object. When a user interacts with an actionable region, a more detailed pictorial from the hierarchy is presented representing that portion of the object, along with real-time feedback in the form of a popup pane containing information about that region, and counts-by-type reflecting the number of items that are available within the system associated with the specific context and search filters established at that point in time
Image and information management system
A system and methods through which pictorial views of an object's configuration, arranged in a hierarchical fashion, are navigated by a person to establish a visual context within the configuration. The visual context is automatically translated by the system into a set of search parameters driving retrieval of structured data and content (images, documents, multimedia, etc.) associated with the specific context. The system places hot spots, or actionable regions, on various portions of the pictorials representing the object. When a user interacts with an actionable region, a more detailed pictorial from the hierarchy is presented representing that portion of the object, along with real-time feedback in the form of a popup pane containing information about that region, and counts-by-type reflecting the number of items that are available within the system associated with the specific context and search filters established at that point in time
Shape-based peak identification for ChIP-Seq
We present a new algorithm for the identification of bound regions from
ChIP-seq experiments. Our method for identifying statistically significant
peaks from read coverage is inspired by the notion of persistence in
topological data analysis and provides a non-parametric approach that is robust
to noise in experiments. Specifically, our method reduces the peak calling
problem to the study of tree-based statistics derived from the data. We
demonstrate the accuracy of our method on existing datasets, and we show that
it can discover previously missed regions and can more clearly discriminate
between multiple binding events. The software T-PIC (Tree shape Peak
Identification for ChIP-Seq) is available at
http://math.berkeley.edu/~vhower/tpic.htmlComment: 12 pages, 6 figure
Industrial Homes, Domestic Factories: The Convergence of Public and Private Space in Interwar Britain
Conceiving time?: women who do or do not conceive
This article explores the importance of time for an understanding of women's experiences of reproductive identity. In order to do this we draw on data from two separate qualitative research projects. The first project is concerned with the experiences of conception, pregnancy, childbirth and early motherhood in primagravidae, whilst the second focuses on the experiences of individuals (especially women) who defined themselves (at the time of the fieldwork, or some time previously) as 'involuntarily childless' and/or 'infertile'. These two areas are usually treated as separate; however this article explores similarities between them in terms of time and medicalisation. Our central concern then is with exploring the similarities of experience for women who do or do not conceive
Evolution of the sugar receptors in insects
<p>Abstract</p> <p>Background</p> <p>Perception of sugars is an invaluable ability for insects which often derive quickly accessible energy from these molecules. A distinctive subfamily of eight proteins within the gustatory receptor (Gr) family has been identified as sugar receptors (SRs) in <it>Drosophila melanogaster </it>(Gr5a, Gr61a, and Gr64a-f). We examined the evolution of these SRs within the 12 available Drosophila genome sequences, as well as three mosquito, two moth, and beetle, bee, and wasp genome sequences.</p> <p>Results</p> <p>While most Drosophila species retain all eight genes, we find that the three Drosophila subgenus species have lost Gr64d, while <it>D. grimshawi </it>and the <it>D. pseudoobscura/persimilis </it>sibling species have also lost Gr5a function. The entire Gr64 gene complex was also duplicated in the <it>D. grimshawi </it>lineage, but only one potentially functional copy of each gene has been retained. The numbers of SRs range from two in the hymenopterans <it>Apis mellifera </it>and <it>Nasonia vitripennis </it>to 16 in the beetle <it>Tribolium castaneum</it>. An unusual aspect is the evolution of a novel exon from intronic sequence in an expanded set of four SRs in <it>Bombyx mori </it>(BmGr5-8), which appears to be the first example of such exonization in insects. Twelve intron gains and 63 losses are inferred within the SR family.</p> <p>Conclusion</p> <p>Examination of the SRs in these fly, mosquito, moth, beetle, and hymenopteran genome sequences reveals that they appear to have originated independently from single ancestral genes within the dipteran and coleopteran lineages, and two genes in the lepidopteran and hymenopteran lineages. The origin of the insect SRs will eventually be illuminated by additional basal insect and arthropod genome sequences.</p
The Herschel Virgo cluster survey: V. Star-forming dwarf galaxies - dust in metal-poor environments
We present the dust properties of a small sample of Virgo cluster dwarf
galaxies drawn from the science demonstration phase data set of the Herschel
Virgo Cluster Survey. These galaxies have low metallicities (7.8 < 12 +
log(O/H) < 8.3) and star-formation rates < 10^{-1} M_{sun}/yr. We measure the
spectral energy distribution (SED) from 100 to 500 um and derive dust
temperatures and dust masses. The SEDs are fitted by a cool component of
temperature T < 20 K, implying dust masses around 10^{5} M_{sun} and
dust-to-gas ratios D within the range 10^{-3}-10^{-2}. The completion of the
full survey will yield a larger set of galaxies, which will provide more
stringent constraints on the dust content of star-forming dwarf galaxies.Comment: Letter accepted for publication in A&A (Herschel special issue
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