1,106 research outputs found
Differential quadrature solutions to dynamic response of cylindrical shell subjected to thermal shock
The dynamic response of the cylindrical shell subjected to thermal shock is investigated. Based on the classical shell theory, dynamic governing equations of thin shell with the simply supported edges under thermal shock are derived by using Hamilton principle. The temperature field, the thermal axial force and the thermal bending moment are obtained in combination of Laplace transform and series expansion when the internal surface of shell is subjected to thermal shock loading. Considering of the axisymmetric deformation, the transient displacements and thermal stresses of the shell are obtained using the differential quadrature method. The effects of the thermal shock load and the geometrical parameters of the cylindrical shell on the central deflection, the axial displacement, the bending configurations and the transient thermal stresses are analyzed
Carnosol Modulates Th17 Cell Differentiation and Microglial Switch in Experimental Autoimmune Encephalomyelitis
Medicinal plants as a rich pool for developing novel small molecule therapeutic medicine have been used for thousands of years. Carnosol as a bioactive diterpene compound originated from Rosmarinus officinalis (Rosemary) and Salvia officinalis, herbs extensively applied in traditional medicine for the treatment of multiple autoimmune diseases (1). In this study, we investigated the therapeutic effects and molecule mechanism of carnosol in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Carnosol treatment significantly alleviated clinical development in the myelin oligodendrocyte glycoprotein (MOG35–55) peptide-induced EAE model, markedly decreased inflammatory cell infiltration into the central nervous system and reduced demyelination. Further, carnosol inhibited Th17 cell differentiation and signal transducer and activator of transcription 3 phosphorylation, and blocked transcription factor NF-κB nuclear translocation. In the passive-EAE model, carnosol treatment also significantly prevented Th17 cell pathogenicity. Moreover, carnosol exerted its therapeutic effects in the chronic stage of EAE, and, remarkably, switched the phenotypes of infiltrated macrophage/microglia. Taken together, our results show that carnosol has enormous potential for development as a therapeutic agent for autoimmune diseases such as MS
A multi-wavelength observation and investigation of six infrared dark clouds
Context. Infrared dark clouds (IRDCs) are ubiquitous in the Milky Way, yet
they play a crucial role in breeding newly-formed stars.
Aims. With the aim of further understanding the dynamics, chemistry, and
evolution of IRDCs, we carried out multi-wavelength observations on a small
sample.
Methods. We performed new observations with the IRAM 30 m and CSO 10.4 m
telescopes, with tracers , HCN, , ,
DCO, SiO, and DCN toward six IRDCs G031.97+00.07, G033.69-00.01,
G034.43+00.24, G035.39-00.33, G038.95-00.47, and G053.11+00.05.
Results. We investigated 44 cores including 37 cores reported in previous
work and seven newly-identified cores. Toward the dense cores, we detected 6
DCO, and 5 DCN lines. Using pixel-by-pixel spectral energy distribution
(SED) fits of the 70 to 500 m, we obtained dust
temperature and column density distributions of the IRDCs. We found that emission has a strong correlation with the dust temperature and column
density distributions, while showed the weakest correlation. It
is suggested that is indeed a good tracer in very dense
conditions, but is an unreliable one, as it has a relatively
low critical density and is vulnerable to freezing-out onto the surface of cold
dust grains. The dynamics within IRDCs are active, with infall, outflow, and
collapse; the spectra are abundant especially in deuterium species.
Conclusions. We observe many blueshifted and redshifted profiles,
respectively, with and toward the same core. This
case can be well explained by model "envelope expansion with core collapse
(EECC)".Comment: 24 pages, 11 figures, 4 tables. To be published in A&A. The
resolutions of the pictures are cut dow
Spatial clustering and common regulatory elements correlate with coordinated gene expression
Many cellular responses to surrounding cues require temporally concerted
transcriptional regulation of multiple genes. In prokaryotic cells, a
single-input-module motif with one transcription factor regulating multiple
target genes can generate coordinated gene expression. In eukaryotic cells,
transcriptional activity of a gene is affected by not only transcription
factors but also the epigenetic modifications and three-dimensional chromosome
structure of the gene. To examine how local gene environment and transcription
factor regulation are coupled, we performed a combined analysis of time-course
RNA-seq data of TGF-\b{eta} treated MCF10A cells and related epigenomic and
Hi-C data. Using Dynamic Regulatory Events Miner (DREM), we clustered
differentially expressed genes based on gene expression profiles and associated
transcription factors. Genes in each class have similar temporal gene
expression patterns and share common transcription factors. Next, we defined a
set of linear and radial distribution functions, as used in statistical
physics, to measure the distributions of genes within a class both spatially
and linearly along the genomic sequence. Remarkably, genes within the same
class despite sometimes being separated by tens of million bases (Mb) along
genomic sequence show a significantly higher tendency to be spatially close
despite sometimes being separated by tens of Mb along the genomic sequence than
those belonging to different classes do. Analyses extended to the process of
mouse nervous system development arrived at similar conclusions. Future studies
will be able to test whether this spatial organization of chromosomes
contributes to concerted gene expression.Comment: 30 pages, 9 figures, accepted in PLoS Computational Biolog
Ionic effect on combing of single DNA molecules and observation of their force-induced melting by fluorescence microscopy
Molecular combing is a powerful and simple method for aligning DNA molecules
onto a surface. Using this technique combined with fluorescence microscopy, we
observed that the length of lambda-DNA molecules was extended to about 1.6
times their contour length (unextended length, 16.2 micrometers) by the combing
method on hydrophobic polymethylmetacrylate (PMMA) coated surfaces. The effects
of sodium and magnesium ions and pH of the DNA solution were investigated.
Interestingly, we observed force-induced melting of single DNA molecules.Comment: 12 page
Probing the initial conditions of high-mass star formation -- IV. Gas dynamics and NHD chemistry in high-mass precluster and protocluster clumps
The initial stage of star formation is a complex area study because of its
high density and low temperature. Under such conditions, many molecules become
depleted from the gas phase by freezing out onto dust grains. However, the
deuterated species could remain gaseous and are thus ideal tracers. We
investigate the gas dynamics and NHD chemistry in eight massive
pre/protocluster clumps. We present NHD 1-1 (at 85.926 GHz),
NH (1, 1) and (2, 2) observations in the eight clumps using the PdBI and
the VLA, respectively. We find that the distribution between deuterium
fractionation and kinetic temperature shows a number density peak at around
K, and the NHD cores are mainly located at a temperature
range of 13.0 to 22.0 K. We detect seven instances of extremely high deuterium
fractionation of . We find that the
NHD emission does not appear to coincide exactly with either dust continuum
or NH peak positions, but often surrounds the star-formation active
regions. This suggests that the NHD has been destroyed by the central
young stellar object (YSO) due to its heating. The detected NHD lines are
very narrow with a median width of . The extracted
NHD cores are gravitationally bound (), are likely
prestellar or starless, and can potentially form intermediate-mass or high-mass
stars. Using NH (1, 1) as a dynamical tracer, we find very complicated
dynamical movement, which can be explained by a combined process with outflow,
rotation, convergent flow, collision, large velocity gradient, and rotating
toroids. High deuterium fractionation strongly depends on the temperature
condition. NHD is a poor evolutionary indicator of high-mass star formation
in evolved stages, but a useful tracer in the starless and prestellar cores.Comment: 27 pages, 25 figures, 6 tables, accepted for publication in A&
- …