1,732 research outputs found
Detection of 40-48 GHz dust continuum linear polarization towards the Class 0 young stellar object IRAS 16293-2422
We performed the new JVLA full polarization observations at 40-48 GHz
(6.3-7.5 mm) towards the nearby ( 1473.4 pc) Class 0 YSO IRAS
16293-2422, and compare with the previous SMA observations reported by Rao et
al. (2009; 2014). We observed the quasar J1407+2827 which is weakly polarized
and can be used as a leakage term calibrator for 9 GHz observations, to
gauge the potential residual polarization leakage after calibration. We did not
detect Stokes Q, U, and V intensities from the observations of J1407+2827, and
constrain (3-) the residual polarization leakage after calibration to
be 0.3\%. We detect linear polarization from one of the two binary
components of our target source, IRAS\,16293-2422\,B. The derived polarization
position angles from our observations are in excellent agreement with those
detected from the previous observations of the SMA, implying that on the
spatial scale we are probing (50-1000 au), the physical mechanisms for
polarizing the continuum emission do not vary significantly over the wavelength
range of 0.88-7.5 mm. We hypothesize that the observed polarization
position angles trace the magnetic field which converges from large scale to an
approximately face-on rotating accretion flow. In this scenario, magnetic field
is predominantly poloidal on 100 au scales, and becomes toroidal on smaller
scales. However, this interpretation remains uncertain due to the high dust
optical depths at the central region of IRAS\,16293-2422\,B and the uncertain
temperature profile. We suggest that dust polarization at wavelengths
comparable or longer than 7\,mm may still trace interstellar magnetic field.
Future sensitive observations of dust polarization in the fully optically thin
regime will have paramount importance for unambiguously resolving the magnetic
field configuration.Comment: 14 pages, 7 figures, accepted to A&A. Comments are welcom
Granulocyte Colony-Stimulating Factor Activating HIF-1a Acts Synergistically with Erythropoietin to PromoteTissue Plasticity
[[abstract]]"Stroke and peripheral limb ischemia are serious clinical problems with poor prognosis and limited treatment. The
cytokines erythropoietin (EPO) and granulocyte-colony stimulating factor (G-CSF) have been used to induce endogenous
cell repair and angiogenesis. Here, we demonstrated that the combination therapy of EPO and G-CSF exerted synergistic
effects on cell survival and functional recovery from cerebral and peripheral limbs ischemia. We observed that even under
normoxic conditions, G-CSF activates hypoxia-inducible factor-1a (HIF-1a), which then binds to the EPO promoter and
enhances EPO expression. Serum EPO level was significantly increased by G-CSF injection, with the exception of Tg-HIF-
1a
+f/+f
mice. The neuroplastic mechanisms exerted by EPO combined with G-CSF included enhanced expression of the
antiapoptotic protein of Bcl-2, augmented neurotrophic factors synthesis, and promoted neovascularization. Further, the
combination therapy significantly increased homing and differentiation of bone marrow stem cells (BMSCs) and intrinsic
neural progenitor cells (INPCs) into the ischemic area. In summary, EPO in combination with G-CSF synergistically
enhanced angiogenesis and tissue plasticity in ischemic animal models, leading to greater functional recovery than either
agent alone.
MicroRNAs Regulation Modulated Self-Renewal and Lineage Differentiation of Stem Cells
[[abstract]]Stem cells are unique cells in the ability that can self-renew and differentiate into a wide variety of cell types, suggesting that a specific molecular control network underlies these features. To date, stem cells have been applied to many clinical therapeutic approaches. For example, hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) are the cells responding to ischemia or injury and engage in effective revascularization to repair within impairment regions. Transplantation of MSCs after stroke and hindlimb ischemia results in remarkable recovery through enhancing angiogenesis. MicroRNAs are a novel class of endogenous, small, noncoding RNAs that work via translational inhibition or degradation of their target mRNAs to downregulate gene expression. MicroRNAs have been strongly linked to stem cells, which have a remarkable role in development. In this study, we focused on the microRNA regulation in multiple stem cells. For example, miR-520h was upregulated and miR-129 was downregulated in HSC. MiR-103, 107, 140, 143, 638, and 663 were associated with MSCs while miR-302s and miR-136 were associated with ESCs. In NSCs, miR-92b, let-7, and miR-125 were the critical regulators. This overview of the recent advances in the aspects of molecular control of stem cell biology reveals the importance of microRNAs, which may be helpful for future work
Innovative digital technology adapted in nursing education between Eastern and Western countries: a mini-review
Advanced digital technologies have overcome the limitation of on-site teaching, especially after the COVID-19 epidemic. Various newly-developed digital technologies, such as e-learning, virtual reality, serious games, and podcasts, have gained renewed interest and come into the spotlight. Podcasts are becoming increasingly popular in nursing education as they provide a convenient and cost-effective way for students to access educational content. This mini-review article provides an overview of the development of podcasts in nursing education in Eastern and Western countries. It explores potential future trends in the use of this technology. The literature review demonstrates that nursing education in Western countries has already integrated podcasts into curriculum design, using the podcast to convey nursing education knowledge and skills and to improve students’ learning outcomes. However, few articles address nursing education in Eastern countries. The benefits of integrating podcasts into nursing education appear far greater than the limitations. In the future, the application of podcasts can serve not only as a supplement to instructional methodologies but also as a tool for clinical practicing students in nursing education. In addition, with the aging population increasing in both Eastern and Western countries, podcasts have the potential to serve as an effective delivery modality for health education in the future, particularly for the older adult, whose eyesight declines with age, and those populations with visual impairments
On Connected Target Coverage for Wireless Heterogeneous Sensor Networks with Multiple Sensing Units
The paper considers the connected target coverage (CTC) problem in wireless heterogeneous sensor networks (WHSNs) with multiple sensing units, termed MU-CTC problem. MU-CTC problem can be reduced to a connected set cover problem and further formulated as an integer linear programming (ILP) problem. However, the ILP problem is an NP-complete problem. Therefore, two distributed heuristic schemes, REFS (remaining energy first scheme) and EEFS (energy efficiency first scheme), are proposed. In REFS, each sensor considers its remaining energy and its neighbors’ decisions to enable its sensing units and communication unit such that all targets can be covered for the required attributes and the sensed data can be delivered to the sink. The advantages of REFS are its simplicity and reduced communication overhead. However, to utilize sensors’ energy efficiently, EEFS is proposed. A sensor in EEFS considers its contribution to the coverage and the connectivity to make a better decision. To our best knowledge, this paper is the first to consider target coverage and connectivity jointly for WHSNs with multiple sensing units. Simulation results show that REFS and EEFS can both prolong the network lifetime effectively. EEFS outperforms REFS in network lifetime, but REFS is simpler
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