37 research outputs found
Dwarf galaxies with the highest concentration are not thicker than ordinary dwarf galaxies
The formation mechanism of high-concentration dwarf galaxies is still a
mystery. We perform a comparative study of the intrinsic shape of nearby
low-mass galaxies with different stellar concentration. The intrinsic shape is
parameterized by the intermediate-to-major axis ratios B/A and the
minor-to-major axis ratios C/A of triaxial ellipsoidal models. Our galaxies
( < < ) are selected to have
spectroscopic redshift from SDSS or GAMA, and have broadband optical images
from the HSC-SSP Wide layer survey. The deep HSC-SSP images allow to measure
the apparent axis ratios at galactic radii beyond the central star-forming
area of our galaxies. We infer the intrinsic axis ratios based on the
distributions. We find that 1) our galaxies have typical intrinsic shape
similarly close to be oblate ( 0.9--1), regardless of the
concentration, stellar mass, star formation activity, and local environment
(being central or satellite); 2) galaxies with the highest concentration tend
to have intrinsic thickness similar to or (in virtually all cases) slightly
thinner (i.e. smaller mean or equivalently lower triaxiality) than
ordinary galaxies, regardless of other properties explored here. This appears
to be in contrast with the expectation of the classic merger scenario for
high-concentration galaxies. Given the lack of a complete understanding of
dwarf-dwarf merger, we cannot draw a definite conclusion about the relevance of
mergers in the formation of high-concentration dwarfs. Other mechanisms such as
halo spin may also play important roles in the formation of high-concentration
dwarf galaxies.Comment: 12 pages, 8 figures, 2 tables, accepted for publication in Ap
Cang-ai volatile oil alleviates nasal inflammation via Th1/Th2 cell imbalance regulation in a rat model of ovalbumin-induced allergic rhinitis
We previously revealed that Cang-ai volatile oil (CAVO) regulates T-cell activity, enhancing the immune response in people with chronic respiratory diseases. However, the effects of CAVO on allergic rhinitis (AR) have not been investigated. Herein, we established an ovalbumin (OVA)-induced AR rat model to determine these effects. Sprague–Dawley (SD) rats were exposed to OVA for 3 weeks. CAVO or loratadine (positive control) was given orally once daily for 2 weeks to OVA-exposed rats. Behavior modeling nasal allergies was observed. Nasal mucosa, serum, and spleen samples of AR rats were analyzed. CAVO treatment significantly reduced the number of nose rubs and sneezes, and ameliorated several hallmarks of nasal mucosa tissue remodeling: inflammation, eosinophilic infiltration, goblet cell metaplasia, and mast cell hyperplasia. CAVO administration markedly upregulated expressions of interferon-γ, interleukin (IL)-2, and IL-12, and downregulated expressions of serum tumor necrosis factor-α, IL-4, IL-5, IL-6, IL-13, immunoglobulin-E, and histamine. CAVO therapy also increased production of IFN-γ and T-helper type 1 (Th1)-specific T-box transcription factor (T-bet) of the cluster of differentiation-4+ T-cells in splenic lymphocytes, and protein and mRNA expressions of T-bet in nasal mucosa. In contrast, levels of the Th2 cytokine IL-4 and Th2-specific transcription factor GATA binding protein-3 were suppressed by CAVO. These cumulative findings demonstrate that CAVO therapy can alleviate AR by regulating the balance between Th1 and Th2 cells
Effects of Low-Level Autonomic Stimulation on Prevention of Atrial Fibrillation Induced by Acute Electrical Remodeling
Background. Rapid atrial pacing (RAP) can induce electrical and autonomic remodeling and facilitate atrial fibrillation (AF). Recent reports showed that low-level vagosympathetic nerve stimulation (LLVNS) can suppress AF, as an antiarrhythmic effect. We hypothesized that LLVNS can reverse substrate heterogeneity induced by RAP. Methods and Results. Mongrel dogs were divided into (LLVNS+RAP) and RAP groups. Electrode catheters were sutured to multiple atrial sites, and LLVNS was applied to cervical vagosympathetic trunks with voltage 50% below the threshold slowing sinus rate by ⩽30 msec. RAP induced a significant decrease in effective refractory period (ERP) and increase in the window of vulnerability at all sites, characterized by descending and elevated gradient differences towards the ganglionic plexi (GP) sites, respectively. The ERP dispersion was obviously enlarged by RAP and more significant when the ERP of GP-related sites was considered. Recovery time from AF was also prolonged significantly as a result of RAP. LLVNS could reverse all these changes induced by RAP and recover the heterogeneous substrate to baseline. Conclusions. LLVNS can reverse the electrical and autonomic remodeling and abolish the GP-central gradient differences induced by RAP, and thus it can recover the homogeneous substrate, which may be the underlying mechanism of its antiarrhythmic effect
A new parameter for product configuration in software product lines
Software product line development is a new software engineering method. It promotes the predictive software reuse by developing similar software systems together. One of the key artifacts of a software product line is the feature model, which represents the commonality and variability of all the products in the product family. When developing a member product from the product line, based on the requirement of the final product, features from the feature model will be selected and configured to form the final product. As the requirement could be incomplete or vague, the software engineer might need additional information in assisting with the feature selection. In this paper, we propose a new parameter, called the instantiation space, which measures the relative impact on the rest of the system for a selection. We believe that such information will be very helpful in the process of product configuration
4FGL J1318.2+6754: A Long Orbital-period Redback Candidate
By combining the Fermi catalog and the single-lined spectroscopic binaries of Gaia Data Release 3 (DR3), we report a new candidate redback millisecond pulsar binary, which is recommended as a target for radio telescopes to detect pulsed signals. Using TESS data in the T band spanning over 4 yr, we find a period of ∼4.13 days, which is consistent with the radial velocity solution of the Gaia DR3 and optical spectroscopy from the LAMOST telescope. The light curve in the T band reveals periodic modulation of low amplitude that is a characteristic feature of the heating of the photosphere of a nondegenerate low-mass stellar companion by the pulsar wind. The nondegenerate companion is a bright ( G = 11.96), slightly metal-poor ([Fe/H] = − 0.55), G-type main-sequence star ( T _eff = 5891 K; R = 1.356 R _⊙ ). This orbital period of 4.13 days would be the longest one for known redback candidates, which could hardly be understood for its formation in the standard recycling scenario due to its large Roche-lobe radius (≫the radius of the G-type main-sequence star). It is proposed here that this candidate redback millisecond pulsar binary could be created via accretion-induced collapse of an oxygen–neon–magnesium white dwarf
Mesenchymal Stem Cells Exploit Extracellular Matrix as Mechanotransducer
While stem cells can sense and respond to physical properties of their environment, the molecular aspects how physical information is translated into biochemical signals remain unknown. Here we show that human mesenchymal stem cells (hMSCs) harvest and assemble plasma fibronectin into their extracellular matrix (ECM) fibrils within 24 hours. hMSCs pro-actively pull on newly assembled fibronectin ECM fibrils, and the fibers are more stretched on rigid than on soft fibronectin-coated polyacrylamide gels. Culturing hMSCs on single stretched fibronectin fibers upregulates hMSC osteogenesis. Osteogenesis was increased when αvβ3 integrins were blocked on relaxed fibronectin fibers, and decreased when α5β1 integrins were blocked or when epidermal growth factor (EGF) receptor signaling was inhibited on stretched fibronectin fibers. This suggests that hMSCs utilize their own contractile forces to translate environmental cues into differential biochemical signals by stretching fibronectin fibrils. Mechanoregulation of fibronectin fibrils may thus serve as check point to regulate hMSC osteogenesis.ISSN:2045-232
Modelling and Simulation of Vessel Surgery based on Mass-spring
As the technology developing, precision and accuracy required in medical surgery can be realized through virtual-reality technology in computer aided systems, so that it can satisfy with medical experiments and teaching. In surgery simulation on soft tissues, Mass-spring takes the important roles on simulating the surface transformation of tissues. In this article, we established an intelligent simulation platform for surgery of vein in which includes the transformation based on Mass-spring. This platform can provide good human-computer interface and control some simple motions. It is convenient for medical teaching to instruct the operation scene
Modelling and Simulation of Vessel Surgery based on Mass-spring
As the technology developing, precision and accuracy required in medical surgery can be realized through virtual-reality technology in computer aided systems, so that it can satisfy with medical experiments and teaching. In surgery simulation on soft tissues, Mass-spring takes the important roles on simulating the surface transformation of tissues. In this article, we established an intelligent simulation platform for surgery of vein in which includes the transformation based on Mass-spring. This platform can provide good human-computer interface and control some simple motions. It is convenient for medical teaching to instruct the operation scene