X-ray Astronomical Point Sources Recognition Using Granular Binary-tree SVM

The study on point sources in astronomical images is of special importance, since most energetic celestial objects in the Universe exhibit a point-like appearance. An approach to recognize the point sources (PS) in the X-ray astronomical images using our newly designed granular binary-tree support vector machine (GBT-SVM) classifier is proposed. First, all potential point sources are located by peak detection on the image. The image and spectral features of these potential point sources are then extracted. Finally, a classifier to recognize the true point sources is build through the extracted features. Experiments and applications of our approach on real X-ray astronomical images are demonstrated. comparisons between our approach and other SVM-based classifiers are also carried out by evaluating the precision and recall rates, which prove that our approach is better and achieves a higher accuracy of around 89%.Comment: Accepted by ICSP201

A Study of the Merger History of the Galaxy Group HCG 62 Based on X-Ray Observations and SPH Simulations

We choose the bright compact group HCG 62, which was found to exhibit both excess X-ray emission and high Fe abundance to the southwest of its core, as an example to study the impact of mergers on chemical enrichment in the intragroup medium. We first reanalyze the high-quality Chandra and XMM-Newton archive data to search for the evidence for additional SN II yields, which is expected as a direct result of the possible merger-induced starburst. We reveal that, similar to the Fe abundance, the Mg abundance also shows a high value in both the innermost region and the southwest substructure, forming a high-abundance plateau, meanwhile all the SN Ia and SN II yields show rather flat distributions in $>0.1r_{200}$ in favor of an early enrichment. Then we carry out a series of idealized numerical simulations to model the collision of two initially isolated galaxy groups by using the TreePM-SPH GADGET-3 code. We find that the observed X-ray emission and metal distributions, as well as the relative positions of the two bright central galaxies with reference to the X-ray peak, can be well reproduced in a major merger with a mass ratio of 3 when the merger-induced starburst is assumed. The `best-match' snapshot is pinpointed after the third pericentric passage when the southwest substructure is formed due to gas sloshing. By following the evolution of the simulated merging system, we conclude that the effects of such a major merger on chemical enrichment are mostly restricted within the core region when the final relaxed state is reached.Comment: Accepted for publication in the Astrophysical Journa

Cardioprotective effect of Shenxiong glucose injection on acute myocardial infarction in rats via reduction in myocardial intracellular calcium ion overload

Purpose: To explore the cardioprotective effects and potential mechanisms of Shenxiong Glucose Injection (SGI) in rat acute myocardial infarction (AMI).Methods: AMI model was created by ligating left anterior descending coronary artery. After 7 days’ consecutive intravenous administration of SGI, serum samples were used to conduct biochemical analysis while hearts were excised and processed for infraction size, enzyme activity, histopathology and qPCR studies. Intracellular Ca2+ {(Ca2+)i} overload in H9c2 cells was measured by laser scanning confocal microscope (LSCM).Results: In AMI rats, pretreatment with SGI significantly ameliorated myocardial histopathologic damage. It exerted cardioprotective effect by decreasing myocardial infarct size, electrocardiogram (ECG) ST segment elevation, and CK, cTnI, BNP levels in serum. In addition, SGI significantly decreased calmodulin (CaM) and calmodulin-dependent protein kinase II (CaMK II) mRNA expression, but increased Ca2+-Mg2+-ATPase and Na+-K+-ATPase activities in myocardium. In doxorubicin (DOX)- induced H9c2 cells injury model, SGI reversed (Ca2+)i overload to protect cells.Conclusion: The results demonstrate SGI exerts cardioprotective effect by decreasing myocardial infarct size, restoring ST segment and reversing (Ca2+)i overload. It suggests that SGI may be a new clinical candidate to treat myocardial infarction.Keywords: Shenxiong glucose injection, Tanshinol, Ligustrazine, Myocardial infarction, Intracellular Ca2+ overload, Calmodulin, Calmodulin-dependent protein kinase I

A Novel Prognostic Biomarker of Luminal Breast Cancer: High CD39 Expression Is Related to Poor Survival

BackgroundCD39 is one of the functional surface markers for T regulatory cells, the prognostic role and immune-related effects of CD39 in luminal breast cancer (BC) patients has not been evaluated yet. The aim of the current study was to explore the association between CD39 expression and clinic pathological characteristics and the prognosis in luminal BC patients.MethodsClinical information and RNA-sequencing (RNA-Seq) expression data were extracted from The Cancer Genome Atlas (TCGA). Patients were divided into a high or low CD39 expression group by the optimal cutoff value (4.18) identified from the receiver operating characteristic curve analysis. The relationships between CD39 expression and clinic pathological features were evaluated by the corresponding statistical tests. Survival analyses were applied to evaluate the overall survival between the high and low CD39 expression groups in luminal BC. Furthermore, Gene Expression Omnibus datasets were used for external data validation. Gene set enrichment analysis (GSEA) was also performed, and CIBERSORT was used to analyze the immune cell populations.ResultsAnalysis of 439 cases of tumor data showed that CD39 was overexpressed in luminal BC. The multivariable analysis suggested that CD39 expression was an independent prognostic factor for luminal BC patients. GSEA suggested that CD39 might play an important role in luminal BC progression through immune regulation. Analysis of immune cell patterns revealed high CD39 expression correlated to a higher proportion of CD8+ T cells and M2 macrophages.ConclusionThis study demonstrates that CD39 expression correlates with the prognosis of luminal BC through TCGA database mining. Further studies are warranted further to elucidate this potential novel therapeutic strategy for BC

Single-phase heat transfer and pressure drop performance in a horizontal internal helically-finned tube

Enhanced tubes with internally helical fins have been extensively used in the large heat exchangers. This paper experimentally determined the single-phase friction factor and heat transfer coefficients in an internal helically-finned tube. Parameters of the test tubes are nominal inside diameter (22.48mm), fin height to the tube inside diameter ratio (0.022), number of fins (60), and helix angle (45°). Pressure drop data were collected under isothermal condition and heat transfer experiments are conducted in a flooded evaporator. The aqueous ethylene glycol was used as the working fluid and the tests are performed with the Prandtl number from 18.1 to 29.5 and Reynolds number from 7,000 to 37,000. The heat transfer enhancement ratio hi-en/hi-p and friction enhancement ratio fen/fp increased with Reynolds number and reached maximum at Re>17,000, while efficiency index (hi-en/hi-p)/(fen/fp) decreased with Reynolds number and reached the minimum at Re>17,000. The maximum friction enhancement ratio of 2.13 and the maximum heat transfer enhancement ratio of 3.47 were obtained, while the corresponding minimum efficiency index was 1.62. The maximum efficiency index of 1.86 occurred at the minimum Re in the heat transfer experiments. This study offers a reference on the design of the heat exchangers.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

Falling film mode transition in an array of horizontal tubes : effect of two dimensional and three dimensional fins

Problem of falling film heat transfer is widely associated with many processes, such as shell side condensation and falling film evaporation in shell and tube heat exchangers. Efficient design of such heat exchangers can’t be succeed without detailed knowledge of the falling film flow charts in a tube bundle, especially those consists of two or three dimensional finned tubes. A falling film bundle test facility was built for the above problem. Using water as a cyclic working medium, the effect of tube surface structures on falling film Reynolds number(Re) were investigated under the same flow mode. And falling film mode transitions were observed by image collection system. The results show: 1) Compared with the smooth tube, two dimensional enhanced tube has improved the mode transitions. 2) For two dimensional enhanced tube, surface structure caused the hysteresis occurred in the droplet and droplet-column, droplet-column and column modes. 3) For three dimensional enhanced tube, the hysteresis of it was lower than two dimensional tube occurred in the droplet and droplet-column, droplet and column. Under droplet and droplet-column, column and column-sheet, the transitions were lower than two dimensional tube. The results is the basic reference for the falling film heat transfer problem, and they can be used to guide the development of high efficient falling film evaporator with two and three dimensional finned tubes.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

An approach of point sources detection in X-ray astronomical image using support vector machine

Since most of energy sources in our Universe appear point-like structures,the study of point sources detection method on astronomical images has become significant.In this paper,a point sources detection approach on X-ray astronomical image was proposed.Firstly,a thresholding method was used to separate the background noises.Then,the peak detection method was taken to detect the positions of potential point sources.After that,we extracted spectrum features of point sources and backgrounds,and generated the classification model using the Support Vector Machine.Finally,the correct point sources were got after discarding of spurious detections with the classification model.Our approach was applied to the X-ray image of Galaxy NGC 4552.Compared with “wavdetect”,our approach has the same performance of accuracy with a detection error rate of 5%,but a higher efficiency