1,328 research outputs found
Gene Systems Network Inferred from Expression Profiles in Hepatocellular Carcinogenesis by Graphical Gaussian Model
Hepatocellular carcinoma (HCC) in a liver with advanced-stage chronic hepatitis C (CHC) is induced by hepatitis C virus, which chronically infects about 170 million people worldwide. To elucidate the associations between gene groups in hepatocellular carcinogenesis, we analyzed the profiles of the genes characteristically expressed in the CHC and HCC cell stages by a statistical method for inferring the network between gene systems based on the graphical Gaussian model. A systematic evaluation of the inferred network in terms of the biological knowledge revealed that the inferred network was strongly involved in the known gene-gene interactions with high significance (P<10−4), and that the clusters characterized by different cancer-related responses were associated with those of the gene groups related to metabolic pathways and morphological events. Although some relationships in the network remain to be interpreted, the analyses revealed a snapshot of the orchestrated expression of cancer-related groups and some pathways related with metabolisms and morphological events in hepatocellular carcinogenesis, and thus provide possible clues on the disease mechanism and insights that address the gap between molecular and clinical assessments
Global Collapses and Expansions in Star-Forming Clouds
Spectral molecular line profile observations of star-forming molecular clouds
sometimes show distinct red asymmetric double-peaked molecular line profiles
with weaker blue peaks and stronger red peaks. For some star-forming molecular
clouds, such molecular transitions with red asymmetric line profiles and blue
asymmetric line profiles (i.e. blue asymmetric double-peaked molecular line
profiles with weaker red peaks and stronger blue peaks) may coexist in
spatially resolved spectral observations, while for others, such molecular
transitions with red asymmetric line profiles may completely dominate in
spatially resolved spectral observations. Blue asymmetric line profiles are
usually interpreted as signals of central core collapses, while red asymmetric
line profiles remain unexplained. In this paper, we advance a spherically
symmetric self-similar hydrodynamic model framework for envelope expansions
with core collapses (EECC) of a general polytropic molecular gas cloud under
self-gravity. Based on such EECC hydrodynamic cloud models, we perform tracer
molecular line profile calculations using the publicly available RATRAN code
for star-forming clouds with spectroscopic signatures of red asymmetric line
profiles. The presence of red asymmetric line profiles from molecular cloud
cores indicates that EECC processes are most likely an essential hydrodynamic
process of star formation. With spatial distributions, we explore various
profiles of molecular lines for several tracer molecules in different settings
of EECC dynamic models with and without shocks.Comment: 12 pages, 7 figures, accepted for publication in MNRA
Activation of Serotonin 2C Receptors in Dopamine Neurons Inhibits Binge-like Eating in Mice
Acknowledgments and Disclosures This work was supported by the National Institutes of Health (Grant Nos. R01DK093587 and R01DK101379 [to YX], R01DK092605 to [QT], R01DK078056 [to MM]), the Klarman Family Foundation (to YX), the Naman Family Fund for Basic Research (to YX), Curtis Hankamer Basic Research Fund (to YX), American Diabetes Association (Grant Nos. 7-13-JF-61 [to QW] and 1-15-BS-184 [to QT]), American Heart Association postdoctoral fellowship (to PX), Wellcome Trust (Grant No. WT098012 [to LKH]), and Biotechnology and Biological Sciences Research Council (Grant No. BB/K001418/1 [to LKH]). The anxiety tests (e.g., open-field test, light-dark test, elevated plus maze test) were performed in the Mouse Neurobehavior Core, Baylor College of Medicine, which was supported by National Institutes of Health Grant No. P30HD024064. PX and YH were involved in experimental design and most of the procedures, data acquisition and analyses, and writing the manuscript. XC assisted in the electrophysiological recordings; LV-T assisted in the histology study; XY, KS, CW, YY, AH, LZ, and GS assisted in surgical procedures and production of study mice. MGM, QW, QT, and LKH were involved in study design and writing the manuscript. YX is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The authors report no biomedical financial interests or potential conflicts of interest.Peer reviewedPublisher PD
In vitro and in vivo effects of insulin-producing cells generated by xeno-antigen free 3D culture with RCP piece
To establish widespread cell therapy for type 1 diabetes mellitus, we aimed to develop an effective protocol for generating insulin-producing cells (IPCs) from adipose-derived stem cells (ADSCs). We established a 3D culture using a human recombinant peptide (RCP) petaloid μ-piece with xeno-antigen free reagents. Briefly, we employed our two-step protocol to differentiate ADSCs in 96-well dishes and cultured cells in xeno-antigen free reagents with 0.1 mg/mL RCP μ-piece for 7 days (step 1), followed by addition of histone deacetylase inhibitor for 14 days (step 2). Generated IPCs were strongly stained with dithizone, anti-insulin antibody at day 21, and microstructures resembling insulin secretory granules were detected by electron microscopy. Glucose stimulation index (maximum value, 4.9) and MAFA mRNA expression were significantly higher in 3D cultured cells compared with conventionally cultured cells (P < 0.01 and P < 0.05, respectively). The hyperglycaemic state of streptozotocin-induced diabetic nude mice converted to normoglycaemic state around 14 days after transplantation of 96 IPCs under kidney capsule or intra-mesentery. Histological evaluation revealed that insulin and C-peptide positive structures existed at day 120. Our established xeno-antigen free and RCP petaloid μ-piece 3D culture method for generating IPCs may be suitable for clinical application, due to the proven effectiveness in vitro and in vivo
Characterizing the velocity field in hydrodynamical simulations of low-mass star formation using spectral line profiles
When low-mass stars form, the collapsing cloud of gas and dust goes through
several stages which are usually characterized by the shape of their spectral
energy distributions. Such classification is based on the cloud morphology only
and does not address the dynamical state of the object. In this paper we
investigate the initial cloud collapse and subsequent disk formation through
the dynamical behavior as reflected in the sub-millimeter spectral emission
line profiles. If a young stellar object is to be characterized by its
dynamical structure it is important to know how accurately information about
the velocity field can be extracted and which observables provide the best
description of the kinematics. Of particular interest is the transition from
infalling envelope to rotating disk, because this provides the initial
conditions for the protoplanetary disk, such as mass and size. We use a
hydrodynamical model, describing the collapse of a core and formation of a
disk, to produce synthetic observables which we compare to calculated line
profiles of a simple parameterized model. Because we know the velocity field
from the hydrodynamical simulation we can determine in a quantitative way how
well our best-fit parameterized velocity field reproduces the original. We use
a molecular line excitation and radiation transfer code to produce spectra of
both our hydro dynamical simulation as well as our parameterized model. We find
that information about the velocity field can reasonably well be derived by
fitting a simple model to either single-dish lines or interferometric data, but
preferentially by using a combination of the two. Our result shows that it is
possible to establish relative ages of a sample of young stellar objects using
this method, independently of the details of the hydrodynamical model.Comment: 12 pages, 11 figures, accepted for publication in A&A on June 1
Molecular Line Profiles of Collapsing Gas Clouds
Emission line profiles of tracer molecule HCO 140 GHz transition from
gravitational core collapsing clouds in the dynamic process of forming
protostars are calculated, using a simple ray-tracing radiative transfer model.
Three self-similar dynamic inside-out core collapse models -- the conventional
polytropic model, the empirical hybrid model and the isothermal model -- for
star-forming molecular clouds are examined and compared. The isothermal model
cannot produce observed asymmetric double-peak molecular line profiles. The
conventional polytropic model, which gives flow velocity, mass density and
temperature profiles self-consistently, can produce asymmetric double-peak line
profiles for a core collapsing cloud. In particular, the blue peak is stronger
than the red peak, consistent with a broad class of molecular line profile
observations. The relative strengths of the blue and red peaks within a
molecular line profile are determined by the cloud temperature gradient. The
conventional polytropic model can be utilized to produce molecular line-profile
templates, for extracting dynamical information from line spectra of molecular
globules undergoing a gravitational core collapse. We show a sample fit using
the 140 GHz HCO emission line from the central region of the molecular
globule B335 by our model with . The calculation of line profiles
and fitting processes also offer a scenario to estimate the protostellar mass,
the kernel mass accretion rate, and the evolution time scale of a core
collapsing cloud. Our model can be readily adapted to other tracer molecules
with more or less constant abundances in star-forming clouds.Comment: 12 pages, 10 figures, accepted for publication in MNRA
Massive star formation around I05345+3157 -- I. The dense gas
We present observations of the intermediate to massive star-forming region
I05345+3157 using the molecular line tracer CS(2-1) with CARMA to reveal the
properties of the dense gas cores. Seven gas cores are identified in the
integrated intensity map of CS(2-1). Among these, core 1 and core 3 have
counterparts in the 2.7 millimeter continuum data. We suggest that core 1 and
core 3 are star-forming cores that may already or will very soon harbor young
massive protostars. The total masses of core 1 estimated from the LTE method
and dust emission by assuming a gas-to-dust ratio are 5 +- 1 solar masses and
18 +- 6 solar masses, and that of core 3 are 15 +- 7 solar masses and 11 +- 3
solar masses. The spectrum of core 3 shows blue-skewed self-absorption, which
suggests gas infall -- a collapsing core. The observed broad linewidths of the
seven gas cores indicate non-thermal motions. These non-thermal motions can be
interactions with nearby outflows or due to the initial turbulence; the former
is observed, while the role of initial turbulence is less certain. Finally, the
virial masses of the gas cores are larger than the LTE masses, which for a
bound core implies a requirement on the external pressure of ~ 10^8 K/cm^3. The
cores have the potential to further form massive stars.Comment: Accepted for publication in MNRA
A deeply embedded young protoplanetary disk around L1489 IRS observed by the submillimeter array
Circumstellar disks are expected to form early in the process that leads to
the formation of a young star, during the collapse of the dense molecular cloud
core. It is currently not well understood at what stage of the collapse the
disk is formed or how it subsequently evolves. We aim to identify whether an
embedded Keplerian protoplanetary disk resides in the L1489 IRS system. Given
the amount of envelope material still present, such a disk would respresent a
very young example of a protoplanetary disk. Using the Submillimeter Array
(SMA) we have observed the HCO 3--2 line with a resolution of about
1. At this resolution a protoplanetary disk with a radius of a few hundred
AUs should be detectable, if present. Radiative transfer tools are used to
model the emission from both continuum and line data. We find that these data
are consistent with theoretical models of a collapsing envelope and Keplerian
circumstellar disk. Models reproducing both the SED and the interferometric
continuum observations reveal that the disk is inclined by 40 which is
significantly different to the surrounding envelope (74). This
misalignment of the angular momentum axes may be caused by a gradient within
the angular momentum in the parental cloud or if L1489 IRS is a binary system
rather than just a single star. In the latter case, future observations looking
for variability at sub-arcsecond scales may be able to constrain these
dynamical variations directly. However, if stars form from turbulent cores, the
accreting material will not have a constant angular momentum axis (although the
average is well defined and conserved) in which case it is more likely to have
a misalignment of the angular momentum axes of the disk and the envelope.Comment: 11 pages, 13 figures, accepted by A&
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