58 research outputs found
Broadband Dark Matter Axion Detection using a Cylindrical Capacitor
The cosmological axions/axion-like particles can compose a significant part
of dark matter, however the uncertainty of their mass is large. Here we propose
to search the axions using a cylindrical capacitor, in which the static
electric field converts dark matter axions into an oscillating magnetic field.
Using a static electric field can greatly reduce the magnetic field background
compared to using the field that the thermal current in the
magnet-coil could be hard to annihilate. A cylindrical setup shields the
electric field to the laboratory as well as encompasses the axion induced
magnetic field within the capacitor, which results an increased magnetic field
strength. The induced oscillating magnetic field then can be picked up by a
SQUID-based magnetic-meter. Adding a superconductor ring-coil system into the
induced magnetic field region can further boost the sensitivity and maintain
the axion dark matter inherent bandwidth. The proposed setup is capable of a
wide mass range searches as the signal can also be modulated by adjusting the
angle between the electric field and the axion flow.Comment: 4 pages, 2 figure
The Minimal UV-induced Effective QCD Axion Theory
The characteristic axion couplings could be generated via effective couplings
between the Standard Model (SM) fermions to a pseudo-Goldstone from a
high-scale Peccei-Quinn (PQ) symmetry breaking. Assuming that the
UV-induced effective operators generate necessary couplings before the PQ
symmetry breaking, and any low-scale couplings to the SM are restricted to the
Yukawa sector, three minimal natural scenarios can be formulated, which
provides a connection between the QCD-axions and mediators at the GUT/string
scales. We find that the PQ symmetry breaking scale could be about
GeV, higher than the classical QCD dark matter axion window but possible if the
anthropic window is considered. We also propose an experiment to probe such
scenarios. If the dark matter axion is discovered, they might suggest that we
live in an atypical Hubble volume.Comment: 4 page
Genetics and phylogeny of genus Coilia in China based on AFLP markers
The taxonomy of Coilia has been extensively studied in China, and yet phylogenetic relationships among component taxa remain controversial. We used a PCR-based fingerprinting technique, amplified fragment length polymorphism (AFLP) to characterize and identify all four species of Coilia in China. We examined the genetic relationships of the four species of Coilia and a subspecies of Coilia nasus with AFLP. A total of 180 AFLP loci were generated from six primer combinations, of which 76.11% were polymorphic. The mean genetic distance between pairs of taxa ranged from 0.047 to 0.596. The neighbor-joining tree and UPGMA dendrogram resolved the investigated species into three separate lineages: (1) C. mystus, (2) C. grayii and (3) C. brachygnathus, C. nasus, and C. nasus taihuensis. Phylogenetic analysis of the AFLP data is inconsistent with current morphological taxonomic systems. The AFLP data indicated a close relationship among C. brachygnathus, C. nasus taihuensis, and C. nasus. Therefore, the two species described under Coilia (C. brachygnathus and C. nasus taihuensis) are treated as synonyms of C. nasus
High-expression of the innate-immune related gene UNC93B1 predicts inferior outcomes in acute myeloid leukemia
Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy with dismal prognosis. Identification of better biomarkers remained a priority to improve established stratification and guide therapeutic decisions. Therefore, we extracted the RNA sequence data and clinical characteristics of AML from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression database (GTEx) to identify the key factors for prognosis. We found UNC93B1 was highly expressed in AML patients and significantly linked to poor clinical features (p < 0.05). We further validated the high expression of UNC93B1 in another independent AML cohort from GEO datasets (p < 0.001) and performed quantitative PCR of patient samples to confirm the overexpression of UNC93B1 in AML (p < 0.005). Moreover, we discovered high level of UNC93B1 was an independent prognostic factor for poorer outcome both in univariate analysis and multivariate regression (p < 0.001). Then we built a nomogram model based on UNC93B1 expression, age, FAB subtype and cytogenetic risk, the concordance index of which for predicting overall survival was 0.729 (p < 0.001). Time-dependent ROC analysis for predicting survival outcome at different time points by UNC93B1 showed the cumulative 2-year survival rate was 43.7%, and 5-year survival rate was 21.9%. The differentially expressed genes (DEGs) between two groups divided by UNC93B1 expression level were enriched in innate immune signaling and metabolic process pathway. Protein–protein interaction (PPI) network indicated four hub genes (S100A9, CCR1, MRC1 and CD1C) interacted with UNC93B1, three of which were also significantly linked to inferior outcome. Furthermore, we discovered high UNC93B1 tended to be infiltrated by innate immune cells, including Macrophages, Dendritic cells, Neutrophils, Eosinophils, and NK CD56dim cells. We also found UNC93B1 had a significantly positive correlation with CD14, CD68 and almost all Toll-like receptors. Finally, we revealed negatively correlated expression of UNC93B1 and BCL2 in AML and conjectured that high-UNC93B1 monocytic AML is more resistant to venetoclax. And we found high MCL-1 expression compensated for BCL-2 loss, thus, we proposed MCL-1 inhibitor might overcome the resistance of venetoclax in AML. Altogether, our findings demonstrated the utility of UNC93B1 as a powerful poor prognostic predictor and alternative therapeutic target
PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST
We describe PSR J1926-0652, a pulsar recently discovered with the
Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive
single-pulse detections from FAST and long-term timing observations from the
Parkes 64-m radio telescope, we probed phenomena on both long and short time
scales. The FAST observations covered a wide frequency range from 270 to 800
MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at
least four profile components, short-term nulling lasting from 4 to 450 pulses,
complex subpulse drifting behaviours and intermittency on scales of tens of
minutes. While the average band spacing P3 is relatively constant across
different bursts and components, significant variations in the separation of
adjacent bands are seen, especially near the beginning and end of a burst. Band
shapes and slopes are quite variable, especially for the trailing components
and for the shorter bursts. We show that for each burst the last detectable
pulse prior to emission ceasing has different properties compared to other
pulses. These complexities pose challenges for the classic carousel-type
models.Comment: 13pages with 12 figure
MicroRNAs Up-Regulated by CagA of Helicobacter pylori Induce Intestinal Metaplasia of Gastric Epithelial Cells
CagA of Helicobacter pylori is a bacterium-derived oncogenic protein closely associated with the development of gastric cancers. MicroRNAs (miRNAs) are a class of widespread non-coding RNAs, many of which are involved in cell growth, cell differentiation and tumorigenesis. The relationship between CagA protein and miRNAs is unclear. Using mammalian miRNA profile microarrays, we found that miRNA-584 and miRNA-1290 expression was up-regulated in CagA-transformed cells, miRNA-1290 was up-regulated in an Erk1/2-dependent manner, and miRNA-584 was activated by NF-κB. miRNA-584 sustained Erk1/2 activities through inhibition of PPP2a activities, and miRNA-1290 activated NF-κB by knockdown of NKRF. Foxa1 was revealed to be an important target of miRNA-584 and miRNA-1290. Knockdown of Foxa1 promoted the epithelial-mesenchymal transition significantly. Overexpression of miRNA-584 and miRNA-1290 induced intestinal metaplasia of gastric epithelial cells in knock-in mice. These results indicate that miRNA-584 and miRNA-1290 interfere with cell differentiation and remodel the tissues. Thus, the miRNA pathway is a new pathogenic mechanism of CagA
Underground adaptive positioning algorithm based on PSO-BP neural network
A kind of underground adaptive positioning algorithm based on PSO-BP neural network was proposed. In view of the problem that traditional positioning algorithm based on ranging model is sensitive to coal mine environment disturbance and ranging error is large, a fingerprint matching positioning model is selected for positioning. In view of the problem that strong time-varying nature of coal mine environment is easy to increase matching error between the fingerprint information collected in real time and the static fingerprint database information established in offline phase, the beacon node is used as calibration node to better reflect the condition of reference point changes with environment, and avoid adding additional calibration nodes. The dynamic compensation method is used to correct the fingerprint data of the target node in real time without increasing the hardware cost, which solves the problem of poor adaptation of the fingerprint matching positioning model. At the matching positioning stage, PSO is used to optimize weight of BP neural network to accelerate convergence of BP neural network and improve learning speed. The experimental results show that the algorithm is more adapted to the coal mine environment varies with time, and meets the requirement of adaptive underground positioning
Boosting the Electrocatalytic CO2 Reduction Reaction by Nanostructured Metal Materials via Defects Engineering
Electrocatalytic CO2 reduction reaction (CO2RR) is one of the most effective methods to convert CO2 into useful fuels. Introducing defects into metal nanostructures can effectively improve the catalytic activity and selectivity towards CO2RR. This review provides the recent progress on the use of metal nanomaterials with defects towards electrochemical CO2RR and defects engineering methods. Accompanying these ideas, we introduce the structure of defects characterized by electron microscopy techniques as the characterization and analysis of defects are relatively difficult. Subsequently, we present the intrinsic mechanism of how the defects affect CO2RR performance. Finally, to promote a wide and deep study in this field, the perspectives and challenges concerning defects engineering in metal nanomaterials towards CO2RR are put forward
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