867 research outputs found
Diagnosing the particle transport mechanism in the pulsar halo via X-ray observations
Pulsar halos (also termed 'TeV halo') are a new class of -ray sources
in Galaxy, which manifest as extended -ray emission around middle-age
pulsars, as discovered around the Geminga pulsar, the Monogem pulsar and
PSR~J0622+3749 by HAWC and LHAASO. A consensus has been reached that the TeV
emission comes from the inverse Compton scattering of escaping
electrons/positrons from the PWN off soft background radiation field, while the
particle transport mechanism in the halo is still in dispute. Currently, there
are mainly three interpretations, namely, the isotropic, suppressed diffusion
model; the isotropic, unsuppressed diffusion model with considering ballistic
propagation of newly injected particles; the anisotropic diffusion model. While
the predicted gamma-ray surface brightness profiles by all three models can be
more or less consistent with the observation, the implication of the three
models for cosmic-ray transport mechanisms and the properties of interstellar
magnetic field are quite different. In this study, we calculate the anticipated
X-ray emission of pulsar halos under the three models. We show that the
synchrotron radiation of these escaping electrons can produce a corresponding
X-ray halo around the pulsar, and the expected surface brightness profiles are
distinct in three models. We suggest that sensitive X-ray detectors of a large
field of view (such as eROSITA and Einstein Probe) with a reasonably long
exposure time are crucial to understand the formation mechanism of pulsar halos
and serve as a probe to the properties of the interstellar turbulence.Comment: 7 figure
Incorporating Surprisingly Popular Algorithm and Euclidean Distance-based Adaptive Topology into PSO
While many Particle Swarm Optimization (PSO) algorithms only use fitness to
assess the performance of particles, in this work, we adopt Surprisingly
Popular Algorithm (SPA) as a complementary metric in addition to fitness.
Consequently, particles that are not widely known also have the opportunity to
be selected as the learning exemplars. In addition, we propose a Euclidean
distance-based adaptive topology to cooperate with SPA, where each particle
only connects to k number of particles with the shortest Euclidean distance
during each iteration. We also introduce the adaptive topology into
heterogeneous populations to better solve large-scale problems. Specifically,
the exploration sub-population better preserves the diversity of the population
while the exploitation sub-population achieves fast convergence. Therefore,
large-scale problems can be solved in a collaborative manner to elevate the
overall performance. To evaluate the performance of our method, we conduct
extensive experiments on various optimization problems, including three
benchmark suites and two real-world optimization problems. The results
demonstrate that our Euclidean distance-based adaptive topology outperforms the
other widely adopted topologies and further suggest that our method performs
significantly better than state-of-the-art PSO variants on small, medium, and
large-scale problems
Potential Implications of Quercetin in Autoimmune Diseases
Autoimmune diseases are a worldwide health problem with growing rates of morbidity, and are characterized by breakdown and dysregulation of the immune system. Although their etiology and pathogenesis remain unclear, the application of dietary supplements is gradually increasing in patients with autoimmune diseases, mainly due to their positive effects, relatively safety, and low cost. Quercetin is a natural flavonoid that is widely present in fruits, herbs, and vegetables. It has been shown to have a wide range of beneficial effects and biological activities, including anti-inflammation, anti-oxidation, and neuroprotection. In several recent studies quercetin has reportedly attenuated rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and systemic lupus erythematosus in humans or animal models. This review summarizes the evidence for the pharmacological application of quercetin for autoimmune diseases, which supports the view that quercetin may be useful for their prevention and treatment
A novel prognostic classification integrating lipid metabolism and immune co-related genes in acute myeloid leukemia
BackgroundAs a severe hematological malignancy in adults, acute myeloid leukemia (AML) is characterized by high heterogeneity and complexity. Emerging evidence highlights the importance of the tumor immune microenvironment and lipid metabolism in cancer progression. In this study, we comprehensively evaluated the expression profiles of genes related to lipid metabolism and immune modifications to develop a prognostic risk signature for AML.MethodsFirst, we extracted the mRNA expression profiles of bone marrow samples from an AML cohort from The Cancer Genome Atlas database and employed Cox regression analysis to select prognostic hub genes associated with lipid metabolism and immunity. We then constructed a prognostic signature with hub genes significantly related to survival and validated the stability and robustness of the prognostic signature using three external datasets. Gene Set Enrichment Analysis was implemented to explore the underlying biological pathways related to the risk signature. Finally, the correlation between signature, immunity, and drug sensitivity was explored.ResultsEight genes were identified from the analysis and verified in the clinical samples, including APOBEC3C, MSMO1, ATP13A2, SMPDL3B, PLA2G4A, TNFSF15, IL2RA, and HGF, to develop a risk-scoring model that effectively stratified patients with AML into low- and high-risk groups, demonstrating significant differences in survival time. The risk signature was negatively related to immune cell infiltration. Samples with AML in the low-risk group, as defined by the risk signature, were more likely to be responsive to immunotherapy, whereas those at high risk responded better to specific targeted drugs.ConclusionsThis study reveals the significant role of lipid metabolism- and immune-related genes in prognosis and demonstrated the utility of these signature genes as reliable bioinformatic indicators for predicting survival in patients with AML. The risk-scoring model based on these prognostic signature genes holds promise as a valuable tool for individualized treatment decision-making, providing valuable insights for improving patient prognosis and treatment outcomes in AML
Characterization of the response of IHEP-IME LGAD with shallow carbon to Gamma Irradiation
Low Gain Avalanche Detectors (LGAD), as part of High-Granularity Timing
Detector (HGTD), is crucial to reducing pileup in the upgrading to HL-LHC. Many
studies have been done on the bulk damages of the LGAD. However, there's no
study about the surface radiation hardness of the LGAD sensors with carbon
implanted. The IHEP-IME LGAD version 3 with the shallow carbon and different
interpad separations were irradiated up to 2 MGy by gamma irradiation. The
performance of the IHEP-IME LGAD version 3 before and after irradiation had
been tested, such as the leakage current, break-down voltage, capacitance,
V, and inter-pad resistance. The results showed that apart from minor
fluctuations in some samples, no significant changes concerning inter-pad
separation were observed before and after irradiation. Leakage current and
break-down voltage increase after irradiation, which is considered due to
surface passivation; the overall inter-pad resistance are larger than $10^9\
\Omega_{gl}$ after irradiation. All parameters meet the
requirements of HGTD, and the results indicated that IHEP-IME LGAD v3 has
excellent anti-irradiation performance
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Using the Li-8150 multichannel automatic soil CO2efflux system, soil respiration was measured continuously over a one-year period in a coastal wetland in the Yellow River Delta, China. Environmental and biological factors were measured simultaneously, including temperature, soil water content, aboveground biomass and leaf area index. The results showed that the diurnal variation of soil respiration presented a single-peak curve, but it appeared as multiple peaks when disturbed by soil freezing and surface flooding. Soil respiration showed obvious seasonal dynamics and a single peak curve. The average annual soil respiration was 0.85 μmol CO2·m-2·s-1, and the mean soil respiration rate was 1.22 μmol CO2·m-2·s-1during the growing season. On one-year scale, soil temperature was a major factor influencing soil respiration in the coastal wetland, which explained 87.5% of the variation in soil respiration. On the growing season scale, soil water content and leaf area index accounted for 85% of the seasonal variation of soil respiration.</p
RPTPĪ± controls epithelial adherens junctions, linking E-cadherin engagement to c-Src-mediated phosphorylation of cortactin
Epithelial junctions are fundamental determinants of tissue organization, subject to regulation by tyrosine phosphorylation. Homophilic binding of E-cadherin activates tyrosine kinases, such as Src, that control junctional integrity. Protein tyrosine phosphatases (PTPs) also contribute to cadherin-based adhesion and signaling, but little is known about their specific identity or functions at epithelial junctions. Here, we report that the receptor PTP RPTPĪ± (human gene name PTPRA) is recruited to epithelial adherens junctions at the time of cell-cell contact, where it is in molecular proximity to E-cadherin. RPTPĪ± is required for appropriate cadherin-dependent adhesion and for cyst architecture in three-dimensional culture. Loss of RPTPa impairs adherens junction integrity, as manifested by defective E-cadherin accumulation and peri-junctional F-actin density. These effects correlate with a role for RPTPa in cellular (c)-Src activation at sites of E-cadherin engagement. Mechanistically, RPTPĪ± is required for appropriate tyrosine phosphorylation of cortactin, a major Src substrate and a cytoskeletal actin organizer. Expression of a phosphomimetic cortactin mutant in RPTPĪ±-depleted cells partially rescues F-actin and E-cadherin accumulation at intercellular contacts. These findings indicate that RPTPa controls cadherinmediated signaling by linking homophilic E-cadherin engagement to cortactin tyrosine phosphorylation through c-Src
Molecular Mechanisms of (R,R)ZX-5 on NO Synthesis and Its Anti-Angiogenic Effect
(R,R)ZX-5 is a NO regulatory compound, which could significantly increase choroidal blood flow in New Zealand rabbit. The aim of this paper is to investigate the molecular mechanism of (R,R)ZX-5 promoting NO production. Besides this, we also investigated the antiangiogenic activity of (R,R)ZX-5. Analysis of Western blot showed that (R,R)ZX-5 up-regulated the expression of Akt, p-Akt (Thr473), eNOS and p-eNOS (Ser1177), down-regulated the expression of Cyclin D1 in human retinal endothelial cells and escalated the intracellular free Ca2+ concentration. Additionally, (R,R)ZX-5 inhibited the growth of blood vessels in the chick chorioallantoic membrane model. It is concluded that (R,R)ZX-5 promotes choroidal blood flow through PI3K/Akt-eNOS and Akt-Ca2+-eNOS pathways. Additionally, (R,R)ZX-5 can inhibit angiogenesis
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