Combination of TEM and 3D Atom Probe Study of Microstructure and Alloy Carbide in a Nb-V Micro-Alloyed Steel Tempered at 650℃

Qing-dong Liu,Wen-qing Liu,Shi-jin Zhao 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.4

3D atom probe (3DAP) combined with TEM is applied to characterize the nanostructure and composition of coarsening carbides that precipitate in a Nb-V micro-alloyed steel tempered at 650 °C for 4 h. The results indicate that high temperature tempering of the as-quenched lath-like martensitic structures leads to the coarsening of alloyed carbide in the recovered ferritic matrix. TEM characterization and EDS analysis show that the alloy carbides are typically spherical or ellipsoidal and are enriched with V, Nb and Mo. Crystallographic lattice overlap and distortion create a distinct optical Moiré pattern at the carbide/matrix boundary, as observed by HRTEM. 3DAP gives the compositional distribution at atomic scale in the coarsening carbide and the surrounding matrix. Non-carbide-forming elements such as Si and Al are depleted in the carbide and are enriched at the carbide/matrix heterophase interface. Carbide-forming elements such as Mn, V, Mo and Nb distribute heterogeneously in the whole carbide, leading to the formation of a Mn-, V- and Mo-enriched core and Mo-enriched external shell.

Analysis on Response Prediction of a Single Pile and Pile Groups Based on the Runge-Kutta Method

Dong-dong Pan,Qian-qing Zhang,Shan-wei Liu,Shi-min Zhang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

The conventional load-transfer approach can not consider the interaction of piles, and can not be directly used in the analysis of the response of pile groups. The interactive effects among piles can be taken into account in the shear displacement method based on the principle of superposition. In the present analysis, the shaft displacement of a single pile at a given depth is assumed to be composed of the pile-soil relative displacement developed at the disturbed soil around pile and the elastic vertical soil displacement developed in the soil mass. A new load-transfer function which is very similar to a hyperbolic model is then established to describe the relationship between unit skin friction and shaft displacement at a given depth. Furthermore, a hyperbolic model is used to simulate the relationship between unit end resistance and pile end displacement. As to the analysis of the response of pile groups, the interactive effects among piles are considered by using the shear displacement method. For an individual pile in pile groups, new load-transfer functions are established to capture the relationship between unit skin friction and shaft displacement and the relationship between end resistance and pile end displacement. Based on the fourth order Runge-Kutta method, a modified loadtransfer method is proposed to analyze the response of pile groups considering the interactive effects among piles. The reliability of the present method is checked by using comparisons of the present calculated results, the measured results and the computed values derived from other methods.

Key Point Detection in 3D Reconstruction Based On Human-Computer Interaction

Zhu Shi Wei,Zhang Xiao Guo,Lv Jia Dong,Wang Qing 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1

Aiming at solving problem of points’ redundancy caused by full automatically detecting points and the problem of large workload caused by picking all points manually, I advanced a new method of picking points which is based on Human-Computer Interaction in our 3D reconstruction platform after automatically detecting points. We first detected and matched points automatically and got the homograph matrix between two images, then projected points which were picked by hand on the one image to the other image, at last we would search the interesting feature points in the neighborhood of corresponding points in the two images. Experiments have shown that this method decreases the redundancy brought by large number of points and successfully finds the important feature points, so it lays a good foundation for 3D reconstruction.

Wind loads and wind-resistant behaviour of large cylindrical tanks in square-arrangement group. Part 2: CFD simulation and finite element analysis

Qing Liu,Yang Zhao,Shuqi Cai,Shi-lin Dong 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.6

To investigate the structural behaviour of grouped tanks under wind loads, 2 problems need to be figured out, wind pressures on tank shells and critical loads of the shell under these pressure distribution patterns. Following the wind tunnel tests described in the companion paper, this paper firstly seeks to obtain wind loads on the external wall in a squarely-arranged cylindrical tank group by numerical simulation, considering various layouts. The outcomes demonstrate that the numerical method can provide similar results on wind pressures and better insights on grouping effects through extracted streamlines. Then, geometrically nonlinear analyses are performed using several selected potentially unfavourable wind pressure distributions. It is found that the critical load is controlled by limit point buckling when the tank is empty while excessive deformations when the tank is full. In particular, significant reductions of wind resistance are found on grouped full tanks compared to the isolated tank, considering both serviceability and ultimate limit state, which should receive special attention if the tank is expected to resist severe wind loads with the increase of liquid level.

Wind loads and wind-resistant behaviour of large cylindrical tanks in square-arrangement group. Part 1: Wind tunnel test

Qing Liu,Yang Zhao,Shuqi Cai,Shi-lin Dong 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.6

Large cylindrical floating-roof tanks, constructed as oil containers, are usually distributed regularly in open area and easily exposed to severe wind loads. However, wind pressures around these grouped squat tanks appear to have not been clearly given in design codes or thoroughly studied in existing researches. This paper conducts a detailed investigation on wind loads on the external wall of a four-tank group in square arrangement. To achieve that, wind tunnel tests are carried out on both empty and full tank groups, considering various wind angles and spacing. Results show that 3 regions in elevation can be identified on the tank shell according to the circumferential wind pressure distribution. The upper 2 regions cover a relatively small portion of the shell where excessive negative pressures are spotted, setting an alarm to the design of the top angle and stiffening rings. By comparing results on grouped tanks to those on an isolated tank, grouping effects concerning wind angle, tank position in group and spacing are discussed. Deviations on pressure distributions that will compromise structural safety are outlined, including the increase of negative pressures, the shift of maximum pressure locations as well as the change of positive pressure range. And, several potentially unfavourable wind pressure distributions are selected for further analyses.

Toll-like Receptor 5 Agonist Inhibition of Growth of A549 Lung Cancer Cells in Vivo in a Myd88 Dependent Manner

Zhou, Shi-Xiang,Li, Feng-Sheng,Qiao, Yu-Lei,Zhang, Xue-Qing,Wang, Zhi-Dong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

The purpose of this study was to examine the effect of a Toll-like receptor 5 (TLR5) agonist, CBLB502, on the growth and radiosensitivity of A549 lung cancer cells in vivo. Expression of myeloid differentiation factor 88 (MyD88) or TLR5 was stably knocked down in human lung cancer cells (A549) using lentivirus expressing short hairpin RNA targeting human MyD88 or TLR5. Lack of MyD88 or TLR5 expression enhanced tumor growth in mouse xenografts of A549 lung cancer cells. CBLB502 inhibited the growth of A549 lung cancer cells, not A549-MyD88-KD cells in vivo in the murine xenograft model. Our results showed that the inhibition of A549 by CBLB502 in vivo was realized through regulating the expression of neutrophil recruiting cytokines and neutrophil infiltration. Finally, we found that activation of TLR5 signaling did not affect the radiosensitivity of tumors in vivo.

Association of DNA Base-excision Repair XRCC1, OGG1 and APE1 Gene Polymorphisms with Nasopharyngeal Carcinoma Susceptibility in a Chinese Population

Li, Qing,Wang, Jian-Min,Peng, Yu,Zhang, Shi-Heng,Ren, Tao,Luo, Hao,Cheng, Yi,Wang, Dong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

Background: Numerous carcinogens and reactive oxygen species (ROS) may cause DNA damage including oxidative base lesions that lead to risk of nasopharyngeal carcinoma. Genetic susceptibility has been reported to play a key role in the development of this disease. The base excision repair (BER) pathway can effectively remove oxidative lesions, maintaining genomic stability and normal expression, with X-ray repair crosscomplementing1 (XRCC1), 8-oxoguanine glycosylase-1 (OGG1) and apurinic/apyimidinic endonuclease 1 (APE1) playing important roles. Aims: To analyze polymorphisms of DNA BER genes (OOG1, XRCC1 and APE1) and explore their associations, and the combined effects of these variants, with risk of nasopharyngeal carcinoma. Materials and Methods: We detected SNPs of XRCC1 (Arg399Gln), OGG1 (Ser326Cys), APE1 (Asp148Glu and -141T/G) using the polymerase chain reaction (PCR) with peripheral blood samples from 231 patients with NPC and 300 healthy people, furtherly analyzing their relations with the risk of NPC in multivariate logistic regression models. Results: After adjustment for sex and age, individuals with the XRCC1 399Gln/Gln (OR=1.96; 95%CI:1.02-3.78; p=0.04) and Arg/Gln (OR=1.87; 95%CI:1.29-2.71; p=0.001) genotype variants demonstrated a significantly increased risk of nasopharyngeal carcinoma compared with those having the wild-type Arg/Arg genotype. APE1-141G/G was associated with a significantly reduced risk of NPC (OR=0.40;95%CI:0.18-0.89) in the smoking group. The OR calculated for the combination of XRCC1 399Gln and APE1 148Gln, two homozygous variants, was significantly additive for all cases (OR=2.09; 95% CI: 1.27-3.47; p=0.004). Conclusion: This is the first study to focus on the association between DNA base-excision repair genes (XRCC1, OGG1 and APE1) polymorphism and NPC risk. The XRCC1 Arg399Gln variant genotype is associated with an increased risk of NPC. APE1-141G/G may decrease risk of NPC in current smokers. The combined effects of polymorphisms within BER genes of XRCC1 399Gln and APE1 148Gln may contribute to a high risk of nasopharyngeal carcinoma.

Significance and Application of Digital Breast Tomosynthesis for the BI-RADS Classification of Breast Cancer

Cai, Si-Qing,Yan, Jian-Xiang,Chen, Qing-Shi,Huang, Mei-Ling,Cai, Dong-Lu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9

Background: Full-field digital mammography (FFDM) with dense breasts has a high rate of missed diagnosis, and digital breast tomosynthesis (DBT) could reduce organization overlapping and provide more reliable images for BI-RADS classification. This study aims to explore application of COMBO (FFDM+DBT) for effect and significance of BI-RADS classification of breast cancer. Materials and Methods: In this study, we selected 832 patients who had been treated from May 2013 to November 2013. Classify FFDM and COMBO examination according to BI-RADS separately and compare the differences for glands in the image of the same patient in judgment, mass characteristics display and indirect signs. Employ Paired Wilcoxon rank sum test was used in 79 breast cancer patients to find differences between two examine methods. Results: The results indicated that COMBO pattern is able to observe more details in distribution of glands when estimating content. Paired Wilcoxon rank sum test showed that overall classification level of COMBO is higher significantly compared to FFDM to BI-RADS diagnosis and classification of breast (P<0.05). The area under FFDM ROC curve is 0.805, while that is 0.941 in COMBO pattern. COMBO shows relation of mass with the surrounding tissues, the calcification in the mass, and multiple foci clearly in breast cancer tissues. The optimal sensitivity of cut-off value in COMBO pattern is 82.9%, which is higher than that in FFDM (60%). They share the same specificity which is both 93.2%. Conclusions: Digital Breast Tomosynthesis (DBT) could be used for the BI-RADS classification in breast cancer in clinical.

Toll-like Receptor 5 Agonism Protects Mice from Radiation Pneumonitis and Pulmonary Fibrosis

Wang, Zhi-Dong,Qiao, Yu-Lei,Tian, Xi-Feng,Zhang, Xue-Qing,Zhou, Shi-Xiang,Liu, Hai-Xiang,Chen, Ying Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Radiation pneumonitis and pulmonary fibrosis are the main complications with radiotherapy for thoracic neoplasms, directly limiting the efficient dose in clinical application and currently there are few medicines that effectively function as radioprotectants. However, a TLR5 agonist, CBLB502, was confirmed to have protective efficacy against hematopoietic and gastrointestinal radiation syndromes in mice and primates. This study points to a new direction for protection against thoracic radiation-induced pulmonary syndromes and skin injury by CBLB502. We utilized the TUNEL assay, pathological analysis and immunohistochemistry to obtain evidence thatCBLB502 could alleviate the occurrence of radiation pneumonitis and pulmonary fibrosis as well as radiation-induced skin injury. It may thus play a promising role in facilitating clinical radiotherapy of thoracic neoplasms.

Diffusion-Weighted Imaging for the Left Hepatic Lobe has Higher Diagnostic Accuracy for Malignant Focal Liver Lesions

Han, Xue,Dong, Yin,Xiu, Jian-Jun,Zhang, Jie,Huang, Zhao-Qin,Cai, Shi-Feng,Yuan, Xian-Shun,Liu, Qing-Wei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

Background: This study was conducted to investigate whether apparent diffusion coefficient (ADC) measurements by dividing the liver into left and right hepatic lobes may be utilized to improve the accuracy of differential diagnosis of benign and malignant focal liver lesions. Materials and Methods: A total of 269 consecutive patients with 429 focal liver lesions were examined by 3-T magnetic resonance imaging that included diffusion-weighted imaging. For 58 patients with focal liver lesions of the same etiology in left and right hepatic lobes, ADCs of normal liver parenchyma and focal liver lesions were calculated and compared using the paired t-test. For all 269 patients, ADC cutoffs for focal liver lesions and diagnostic accuracy in the left hepatic lobe, right hepatic lobe and whole liver were evaluated by receiver operating characteristic curve analysis. Results: For the group of 58 patients, mean ADCs of normal liver parenchyma and focal liver lesions in the left hepatic lobe were significantly higher than those in the right hepatic lobe. For differentiating malignant lesions from benign lesions in all patients, the sensitivity and specificity were 92.6% and 92.0% in the left hepatic lobe, 94.4% and 94.4% in the right hepatic lobe, and 90.4% and 94.7% in the whole liver, respectively. The area under the curve of the right hepatic lobe, but not the left hepatic lobe, was higher than that of the whole liver. Conclusions: ADCs of normal liver parenchyma and focal liver lesions in the left hepatic lobe were significantly higher than those in the right hepatic lobe. Optimal ADC cutoff for focal liver lesions in the right hepatic lobe, but not in the left hepatic lobe, had higher diagnostic accuracy compared with that in the whole liver.