48 research outputs found
A new Approach to Erdos Collaboration Network using PageRank
Using the data on Paul Erdos, his co-authors and their co-authors, we can construct a network called the Erd?s Collaboration network. Then we do reduction, analysis and visualization with it using program Pajek. In this paper, we develop a reasonable academic influence measuring method applying PageRank algorithm on the case of the Erd?s Collaboration network. We find that ALON, NOGA M is the most influential mathematician in the network. In addition, to measure impact, we construct a dynamic model, whereas it needs too much data for us to calculate the dynamic index. Keywords: PageRank, Collaboration network, Network analysis
Pathogenic Connexin-31 Forms Constitutively Active Hemichannels to Promote Necrotic Cell Death
Mutations in Connexin-31 (Cx31) are associated with multiple human diseases including erythrokeratodermia variabilis (EKV). The molecular action of Cx31 pathogenic mutants remains largely elusive. We report here that expression of EKV pathogenic mutant Cx31R42P induces cell death with necrotic characteristics. Inhibition of hemichannel activity by a connexin hemichannel inhibitor or high extracellular calcium suppresses Cx31R42P-induced cell death. Expression of Cx31R42P induces ER stress resulting in reactive oxygen species (ROS) production, in turn, to regulate gating of Cx31R42P hemichannels and Cx31R42P induced cell death. Moreover, Cx31R42P hemichannels play an important role in mediating ATP release from the cell. In contrast, no hemichannel activity was detected with cells expressing wildtype Cx31. Together, the results suggest that Cx31R42P forms constitutively active hemichannels to promote necrotic cell death. The Cx31R42P active hemichannels are likely resulted by an ER stress mediated ROS overproduction. The study identifies a mechanism of EKV pathogenesis induced by a Cx31 mutant and provides a new avenue for potential treatment strategy of the disease
Design Optimization for the Thin-Walled Joint Thread of a Coring Tool Used for Deep Boreholes
Threaded joints are key components of core drilling tools. Currently, core drilling tools generally adopt the thread structure designed by the API Spec 7-1 standard. However, fractures easily occur in this thread structure due to high stress concentrations, resulting in downhole accidents. In this paper, according to the needs of large-diameter core drilling, a core barrel joint was designed with an outer diameter of Φ135 mm and a trapezoidal thread profile. Subsequently, a three-dimensional simulation model of the joint was established. The influence of the external load, connection state and thread structure on the stress distribution in the joint was analyzed through simulations, from which the optimal thread structure was determined. Finally, a connection test was carried out on the threaded joint. The stress distribution in the joint thread was indirectly studied by analyzing gas leaks (i.e., the sealing effect) under axial tension. According to the test data and the simulation results, the final joint thread structure was optimized, which lays a good foundation for the design of a core barrel
Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements
In this paper, the magnetocaloric properties of Gd1−xTbx alloys were studied and the optimum composition was determined to be Gd0.73Tb0.27. On the basis of Gd0.73Tb0.27, the influence of different Fe-doping content was discussed and the effect of heat treatment was also investigated. The adiabatic temperature change (ΔTad) obtained by the direct measurement method (under a low magnetic field of 1.2 T) and specific heat capacity calculation method (indirect measurement) was used to characterize the magnetocaloric properties of Gd1−xTbx (x = 0~0.4) and (Gd0.73Tb0.27)1−yFey (y = 0~0.15), and the isothermal magnetic entropy (ΔSM) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔTad. In Gd1−xTbx alloys, the Curie temperature (Tc) decreased from 293 K (x = 0) to 257 K (x = 0.4) with increasing Tb content, and the Gd0.73Tb0.27 alloy obtained the best adiabatic temperature change, which was ~3.5 K in a magnetic field up to 1.2 T (Tc = 276 K). When the doping content of Fe increased from y = 0 to y = 0.15, the Tc of (Gd0.73Tb0.27)1−yFey (y = 0~0.15) alloys increased significantly from 276 K (y = 0) to 281 K (y = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (Gd0.73Tb0.27)1−yFey (y = 0~0.15) at 1073 K for 10 h resulted in an average increase of 0.3 K in the maximum adiabatic temperature change and a slight increase in Tc. This study is of great significance for the study of magnetic refrigeration materials with adjustable Curie temperature in a low magnetic field
The flow and heat performance of tree-like network heat sink with diverging–converging channel
A tree-like network heat sink with diverging–converging channel is designed, and effect of flow rate, channel diverging-converging angles on the flow and heat dissipation performance of the tree-like network heat sink is analysed and compared by numerical simulation. Results show that the diverging– converging angle of 2° can reduce the pressure drop by 14% when inlet mass flow rate is 0.00499kg/s. And the maximum temperature, the temperature difference between the maximum and minimum of the heat sink increases by 0.63K and 0.92K respectively. As the diverging-converging angle increases to 4°, however, it only reduces the pressure drop by 13% and can not bring more pressure drop due to formation of flow recirculation inside the tree-like network heat sink channel. Therefore, the diverging–converging fractal micro-channel heat sink with 2° has good heat dissipation performance with obvious lower pumping power
The complete mitochondrial genome of Reticulitermes ovatilabrum (Isoptera: Rhinotermitidae)
The mitochondrial genome of the Reticulitermes ovatilabrum is 15,913 bp in length and encodes 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and a non-coding control region (D-loop). The percentage of A/T (65.59%) is much higher than that of C/G (34.41%). The phylogenetic tree revealed that R. ovatilabrum was closest to R. kanmonensi and R. periflaviceps. The mitochondrial genome of the R. ovatilabrum provides a resource for evolutional analysis within termites especially Reticulitermes
A Dynamic Scene Vision SLAM Method Incorporating Object Detection and Object Characterization
Simultaneous localization and mapping (SLAM) based on RGB-D cameras has been widely used for robot localization and navigation in unknown environments. Most current SLAM methods are constrained by static environment assumptions and perform poorly in real-world dynamic scenarios. To improve the robustness and performance of SLAM systems in dynamic environments, this paper proposes a new RGB-D SLAM method for indoor dynamic scenes based on object detection. The method presented in this paper improves on the ORB-SLAM3 framework. First, we designed an object detection module based on YOLO v5 and relied on it to improve the tracking module of ORB-SLAM3 and the localization accuracy of ORB-SLAM3 in dynamic environments. The dense point cloud map building module was also included, which excludes dynamic objects from the environment map to create a static environment point cloud map with high readability and reusability. Full comparison experiments with the original ORB-SLAM3 and two representative semantic SLAM methods on the TUM RGB-D dataset show that: the method in this paper can run at 30+fps, the localization accuracy improved to varying degrees compared to ORB-SLAM3 in all four image sequences, and the absolute trajectory accuracy can be improved by up to 91.10%. The localization accuracy of the method in this paper is comparable to that of DS-SLAM, DynaSLAM and the two recent target detection-based SLAM algorithms, but it runs faster. The RGB-D SLAM method proposed in this paper, which combines the most advanced object detection method and visual SLAM framework, outperforms other methods in terms of localization accuracy and map construction in a dynamic indoor environment and has a certain reference value for navigation, localization, and 3D reconstruction
Clinical characteristics and risk of second primary lung cancer after cervical cancer: A population-based study.
BackgroundLung cancer is increasingly common as a second primary malignancy. However, the clinical characteristics of second primary non-small cell lung cancer after cervical cancer (CC-NSCLC) compared with first primary non-small cell lung cancer (NSCLC1) is unknown.MethodsThe Surveillance, Epidemiology, and End Results (SEER) cancer registry between 1998 and 2010 was used to conduct a large population-based cohort analysis. The demographic and clinical characteristics, as well as prognostic data, were systematically analyzed. The overall survival (OS) in the two cohorts was further compared. The risk factors of second primary lung cancer in patients with cervical cancer were also analyzed.ResultsA total of 557 patients (3.52%) developed second primary lung cancer after cervical cancer, and 451 were eligible for inclusion in the final analyses. Compared with NSCLC1, patients with CC-NSCLC had a higher rate of squamous cell carcinoma (SCC) (36.59% vs 19.07%, P ConclusionAge 50-79 years, black race, and history of radiotherapy were independent risk factors for second primary lung cancer in patients with cervical cancer. Patients with CC-NSCLC had distinctive clinical characteristics and better prognosis compared with patients with NSCLC1
Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements
Tunable Mechanical Properties of Ti-Zr-Ni-Cr-V Amorphous Ribbons via Different Melt Spinning Speeds during Rapid Solidification Process
In this paper, the effects of different melt spinning speeds on the mechanical properties of (TiZr)0.5(Ni0.6Cr0.1V0.1)2.1 amorphous ribbons were studied. Tensile tests of the specimens were used to investigate mechanical behavior and mechanical properties of amorphous ribbons. The effects of cooling rate on the glass transition temperature of amorphous ribbons was discussed. The correlation between the microstructure of serrated flow behavior in stress-strain curves and melt spinning speeds of ribbons was also evaluated. In addition, when the spinning speed was 45 m/s, a large number of dense and uniform dimples appeared on the fractured surface of the specimens. Furthermore, characteristics of serrated flow behavior were obvious, which meant that Ti-Zr-Ni-Cr-V amorphous ribbons showed minor plastic behavior. It is assumed that the influence of free volume led to a serrated flow behavior of the amorphous materials, and made the amorphous material exhibit partially plastic properties. Increasing the strain rate sensitivity meant the free volume increased with the increasing spinning speed. Tensile strength (σb) and elongation (δ) of samples exhibited a dramatic increasing trend with an increase in the spinning speed. In particular, Ti-Zr-Ni-Cr-V amorphous ribbons showed better mechanical properties, namely the tensile strength of the amorphous ribbon samples significantly increased from 321 MPa at a spinning speed of 30 m/s to 675 MPa at a speed of 45 m/s. The elongation increased from 0.53% at a speed of 30 m/s to 1.29% at a speed of 45 m/s