98 results on '"Liu, Chunmei"'
Search Results
2. Establishing a 4D-CT lung function related volumetric dose model to reduce radiation pneumonia.
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Liu, Chunmei, Liu, Huizhi, Li, Yange, Xiao, Zhiqing, Wang, Yanqiang, Guo, Han, and Luo, Jianmin
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LUNGS , *PNEUMONIA , *COMPUTED tomography , *RADIATION , *RANDOM forest algorithms , *RECEIVER operating characteristic curves - Abstract
In order to study how to use pulmonary functional imaging obtained through 4D-CT fusion for radiotherapy planning, and transform traditional dose volume parameters into functional dose volume parameters, a functional dose volume parameter model that may reduce level 2 and above radiation pneumonia was obtained. 41 pulmonary tumor patients who underwent 4D-CT in our department from 2020 to 2023 were included. MIM Software (MIM 7.0.7; MIM Software Inc., Cleveland, OH, USA) was used to register adjacent phase CT images in the 4D-CT series. The three-dimensional displacement vector of CT pixels was obtained when changing from one respiratory state to another respiratory state, and this three-dimensional vector was quantitatively analyzed. Thus, a color schematic diagram reflecting the degree of changes in lung CT pixels during the breathing process, namely the distribution of ventilation function strength, is obtained. Finally, this diagram is fused with the localization CT image. Select areas with Jacobi > 1.2 as high lung function areas and outline them as fLung. Import the patient's DVH image again, fuse the lung ventilation image with the localization CT image, and obtain the volume of fLung different doses (V60, V55, V50, V45, V40, V35, V30, V25, V20, V15, V10, V5). Analyze the functional dose volume parameters related to the risk of level 2 and above radiation pneumonia using R language and create a predictive model. By using stepwise regression and optimal subset method to screen for independent variables V35, V30, V25, V20, V15, and V10, the prediction formula was obtained as follows: Risk = 0.23656–0.13784 * V35 + 0.37445 * V30-0.38317 * V25 + 0.21341 * V20-0.10209 * V15 + 0.03815 * V10. These six independent variables were analyzed using a column chart, and a calibration curve was drawn using the calibrate function. It was found that the Bias corrected line and the Apparent line were very close to the Ideal line, The consistency between the predicted value and the actual value is very good. By using the ROC function to plot the ROC curve and calculating the area under the curve: 0.8475, 95% CI 0.7237–0.9713, it can also be determined that the accuracy of the model is very high. In addition, we also used Lasso method and random forest method to filter out independent variables with different results, but the calibration curve drawn by the calibration function confirmed poor prediction performance. The function dose volume parameters V35, V30, V25, V20, V15, and V10 obtained through 4D-CT are key factors affecting radiation pneumonia. Establishing a predictive model can provide more accurate lung restriction basis for clinical radiotherapy planning. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Magnetic-Controlled Short Process Preparation Technique for Phosphor Bronze Based on Structure Refinement.
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Shen, Zhe, Luo, Boyi, Liang, Yuanxin, Zhao, Lun, Zhang, Shunran, Lin, Zhongze, Tang, Ganpei, Shi, Peijian, Zheng, Tianxiang, Zhou, Bangfei, Lu, Haibiao, Li, Qiang, Ding, Biao, Liu, Chunmei, and Zhong, Yunbo
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SOLUTION strengthening ,SOLID solutions ,BRONZE ,PHOSPHORS ,STRESS concentration - Abstract
The conventional preparation process for Phosphor bronze typically involves high-temperature long-duration solid solution treatment to address the issue of decreased workability caused by the precipitation of brittle Sn-rich phases during solidification. However, this solid solution treatment consumes significant energy and lowers production efficiency, which should be avoided. Herein, we propose a magnetic-controlled short process preparation technique that eliminates the need for solid solution treatment. This technique utilizes electromagnetic stirring to refine the grains, dendrites, and brittle Sn-rich phases simultaneously, aiming to relax the stress concentration during plastic deformation and then greatly enhance its workability. This resulting structure refinement offers additional grain refinement strengthening and dislocation strengthening during subsequent thermomechanical processing, thereby compensating for the lack of solid solution strengthening caused by the absence of solid solution treatment. As a result, the samples prepared by the magnetic-controlled short process and conventional process have comparable strength. Furthermore, because of the absence of solid solution treatment in the magnetic-controlled short process, the electrical conductivity of the samples exceeds that of those prepared by the conventional process. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Revealing the Influential Mechanism of the Direct Current on Columnar-to-Equiaxed Transition in Directionally Solidified Al–15Sn–1Cu Alloy Under 10 T Magnetic Field.
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Tang, Ganpei, Zhang, Congjiang, Sun, Zhe, Chen, Liangguo, Zhao, Lun, Lin, Zhongze, Zheng, Tianxiang, Zhou, Bangfei, Shi, Peijian, Li, Qiang, Ren, Weili, Ding, Biao, Shen, Zhe, Liu, Chunmei, and Zhong, Yunbo
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MAGNETIC fields ,DIRECTIONAL solidification ,LORENTZ force ,STRESS concentration ,ALLOYS - Abstract
The effect of the direct current (DC) on the solidification structure in the directional solidification of Al–15Sn–1Cu alloy under 10 T magnetic field was investigated experimentally and numerically. The experimental results show that coarse columnar grains are observed when no DC is applied. However, the microstructure transforms from columnar dendrites to irregular dendrites, and the columnar-to-equiaxed transition (CET) occurs with the application of DC. The numerical results show that the Lorentz force acting on the dendrites can be increased by the application of DC. Additionally, the torque created by the Lorentz force results in the stress concentration at the roots of dendrites arms. The stress increases with the DC when it is larger than the thermoelectric current. Consequently, the dendrites break into fragments when the stress exceeds a certain value and CET occurs. The results indicate that the application of DC facilitates CET at higher withdrawal speeds. Furthermore, this work may initiate a novel method for CET via applying the DC in directional solidification under 10 T magnetic field. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Tension–compression asymmetry in mechanical properties of diamond nanopillars: molecular dynamics simulations.
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Xu, Chao, Zhang, Jing, Liu, Huaping, and Liu, Chunmei
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Introduction of twins into diamond can affect the hardness of diamond, but the underlying microcosmic mechanism remains unknown. Here we have compared the mechanical properties of diamond NPs with three different models, i.e. single crystal nanopillars (SC NPs), twin crystalline nanopillars (TC NPs), and five-fold twinned nanopillars (FT NPs), with diameters from 5 to 30 nm during both tension and compression by molecular dynamics simulations. Our study reveals that the mechanical properties of diamond NPs are closely related to the models of NPs, diameters, and loading modes. The stress–strain responses present significant asymmetry during tension and compression. And the yield strength and strain for FT NPs are always higher than those of TC and SC NPs due to the effect of five-fold twin boundary. The existence of plasticity in diamond NPs is confirmed by the abundance of dislocations after yield strain. The tension–compression asymmetry is also reflected by the differences in dislocation type, dislocation evolution processes, and the fracture shape of the NPs. Moreover, the typical characteristic during tension is that stacking faults are always found following the slip of dislocations, and during compression is that dislocation networks are observed for TC and FT NPs with diameters larger than 20 nm. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Entity alignment based on informative neighbor sampling and multi-embedding graph matching.
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Liu, Chunmei, Gao, Yongbin, and Fang, Zhijun
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Entity alignment is an important and necessary step in the process of knowledge fusion, which aims to match entities with the same meaning in different knowledge graphs. In this paper, we propose a novel entity alignment method based on informative neighbors sampling and multi-embedding graph matching (Multi-EINS). The graphs are embedded by graph convolutional network and the informative neighbors sampling is used to extract the neighborhood region topological structure feature to enhance the entity embedding. Relation and attribution information are embedded to incorporate former entity embedding, resulting representation-level embedding. Semantic and the character information are considered from outcome-level by calculate the distances of entities. The distance matrixes of multi-embedding are fused and the graph matching algorithm is performed on the fused matrix to align entities from different knowledge graphs. Experimental results on real datasets show that our proposed model effectively solves the entity alignment problem and outperforms 14 previous methods by 1% to 3% at least. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Numerical Investigation on Grain Structure of Magnetic-Controlled Electroslag Remelted Ingot Based on CAFE and Equivalent Treatment Method.
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Xia, Zhibin, Sun, Zhonghao, Zhang, Mingliang, Guo, Yifeng, Shen, Zhe, Ding, Biao, Zheng, Tianxiang, Li, Qiang, Liu, Chunmei, and Zhong, Yunbo
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INGOTS ,RESTAURANTS ,THERMAL conductivity ,TEMPERATURE distribution ,DISCONTINUOUS precipitation ,GRAIN - Abstract
A transient two-dimensional axisymmetric model is developed to investigate the influence of the applied transverse static magnetic field (TSMF) on the grain morphology of the electroslag remelted (ESR) ingot. The cellular automata-finite element (CAFE) technique is employed to elucidate the nucleation and growth of the grains. Moreover, an equivalent treatment method by adjusting the effective thermal conductivity is introduced to model the effect of the electromagnetic vibration (EMV) generated by the applied 0.05T TSMF on the temperature distribution. The close correspondence between the experimental data and the simulation outcomes demonstrates the validity and reliability of the computational model. The results show that with the effective thermal conductivity increasing from η to 3 η , the proportion of equiaxed grain increases from 25.1 to 48.7 pct and the grains get refined. Furthermore, the increase in effective thermal conductivity correlates with a decrease in both the local solidification time (LST) and the second dendrite arm spacing (SDAS) at the central region, suggesting a finer microstructure of the ingot. In addition, as the effective thermal conductivity increases, a substantial decrease in the maximum depth of the metal pool is observed, reducing from 53.9 to 19.4 mm, which should be conductive to microstructure refinement and macrosegregation alleviation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. Black holes and non-perturbative gravitational waves in f(R) gravity.
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Liu, Chunmei and Zhang, Hongsheng
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BLACK holes , *SPHERICAL waves , *GRAVITY , *RADIATION absorption , *GRAVITATIONAL waves - Abstract
Exact solutions of spherically symmetric black hole and gravitational wave are explored in f(R) gravity in arbitrary dimension. We find two exact solutions for the radiation and absorption of null dust. In the framework of general relativity, the Birkhoff theorem strictly forbids the existence of spherical gravitational waves in vacuum space. We find spherical non-perturbative gravitational waves, which are shear-free, twist-free, but expanding. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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9. A novel framework for designing and manufacturing cranial prostheses through incremental sheet metal forming.
- Author
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Zheng, Shuo, El-Aty, Ali Abd, Tao, Jie, Guo, Xunzhong, Zha, Guangcheng, Liu, Chunmei, and Cheng, Cheng
- Abstract
This investigation aims to propose a novel framework for designing and manufacturing cranial prostheses through incremental sheet metal forming (ISF). First, the three-dimensional models of the defective crania and the prosthesis were constructed from the CT data. Then, to verify the formability of the prosthesis model, a method for testing the mesh sheet's incremental forming limit (IFL) was proposed with a variable angle cone model. The angle between the normal vector of the fracture point and the Z-axis calculated the IFL. The tests showed that the method could realize the testing of the IFL of the mesh sheet with the reduction of processing time and cost. In addition, finite element modeling and experimental trials were used to evaluate the ISF process of the prosthesis, including thickness distribution and geometric accuracy. The results showed that the incremental forming can form prosthesis samples with high precision, while the thickness distribution is relatively uniform without excessive thinning. Finally, the obtained prosthesis sample was practically assembled with the cranial defect model to verify the fitting effect and feasibility of the prosthesis formed by the ISF process. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Numerical Investigation About the Effect of Axial Static Magnetic Field on Improvement of Metal Pool Profile During Electroslag Remelting Process.
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Xia, Zhibin, Sun, Zhonghao, Zhang, Mingliang, Lin, Wenhao, Zheng, Tianxiang, Shen, Zhe, Ding, Biao, Liu, Chunmei, Lu, Haibiao, Lei, Zuosheng, Guo, Yifeng, Li, Qiang, and Zhong, Yunbo
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ELECTROSLAG process ,MAGNETIC fields ,LORENTZ force ,METALS ,TEMPERATURE distribution - Abstract
A transient two-dimensional (2D) coupled mathematical model was developed to study the effect of external axial static magnetic field (ASMF) on the evolution of metal pool profiles. Electromagnetic flow, heat transfer, and solidification were explored simultaneously in this model. The growth of the ingot was predicted with the dynamic mesh technique. The calculated results indicated that the temperature distribution became more uniform both in slag and metal pool with 0.05-T ASMF. To characterize the metal pool profile more reasonable, the actual depth (H a = H m - H c) is defined to represent the depth of the metal pool. Compared with the case without applying ASMF, the calculated actual metal pool profile was flattened remarkably from 23 to 17.5 mm. Meanwhile, the calculated actual metal pool depth was compared with the measurement, which was from 25.5 to 16 mm, in experiments on a laboratory scale to validate the model. In addition, the mechanisms how ASMF improved the metal pool profile were elaborated thoroughly. Under the interaction of ASMF and the direct current component (DCC), the induced rotating Lorentz force makes the temperature field of slag pool more uniform. As a result, the heat transfer from slag to metal pool becomes more well distributed. On the other hand, the forced flow of metal pool by the drag of slag pool can enhance the effective thermal conductivity of metal pool and then reduce the temperature gradient in radial direction. All of above ultimately lead to a shallower metal pool. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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11. An IgM-like inhalable ACE2 fusion protein broadly neutralizes SARS-CoV-2 variants.
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Liu, Juan, Mao, Fengfeng, Chen, Jianhe, Lu, Shuaiyao, Qi, Yonghe, Sun, Yinyan, Fang, Linqiang, Yeung, Man Lung, Liu, Chunmei, Yu, Guimei, Li, Guangyu, Liu, Ximing, Yao, Yuansheng, Huang, Panpan, Hao, Dongxia, Liu, Zibing, Ding, Yu, Liu, Haimo, Yang, Fang, and Chen, Pan
- Subjects
SARS-CoV-2 ,CHIMERIC proteins ,ANGIOTENSIN converting enzyme ,SARS-CoV-2 Delta variant ,MONOCLONAL antibodies ,GOLDEN hamster - Abstract
Many of the currently available COVID-19 vaccines and therapeutics are not effective against newly emerged SARS-CoV-2 variants. Here, we developed the metallo-enzyme domain of angiotensin converting enzyme 2 (ACE2)—the cellular receptor of SARS-CoV-2—into an IgM-like inhalable molecule (HH-120). HH-120 binds to the SARS-CoV-2 Spike (S) protein with high avidity and confers potent and broad-spectrum neutralization activity against all known SARS-CoV-2 variants of concern. HH-120 was developed as an inhaled formulation that achieves appropriate aerodynamic properties for rodent and monkey respiratory system delivery, and we found that early administration of HH-120 by aerosol inhalation significantly reduced viral loads and lung pathology scores in male golden Syrian hamsters infected by the SARS-CoV-2 ancestral strain (GDPCC-nCoV27) and the Delta variant. Our study presents a meaningful advancement in the inhalation delivery of large biologics like HH-120 (molecular weight (MW) ~ 1000 kDa) and demonstrates that HH-120 can serve as an efficacious, safe, and convenient agent against SARS-CoV-2 variants. Finally, given the known role of ACE2 in viral reception, it is conceivable that HH-120 has the potential to be efficacious against additional emergent coronaviruses. In this study, the authors report the development of an inhalable IgM-like ACE2 and show that it broadly neutralizes SARS-CoV-2 variants, lowers viral loads and lung pathology in hamsters when administered early, and has good safety profiles in rats and monkeys. [ABSTRACT FROM AUTHOR]
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- 2023
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12. Neferine, a novel ROCK1-targeting inhibitor, blocks EMT process and induces apoptosis in non-small cell lung cancer.
- Author
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Hu, Po, Wan, Peng, Xu, Anna, Yan, Binghui, Liu, Chunmei, Xu, Qixuan, Wei, Zhenhuan, Xu, Jingyi, Liu, Siqi, Yang, Guangming, and Pan, Yang
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NON-small-cell lung carcinoma ,CADHERINS ,RHO-associated kinases ,EPITHELIAL-mesenchymal transition ,PROTEIN kinases ,CHINESE medicine ,EAST Indian lotus - Abstract
The compounds derived from Traditional Chinese Medicines have shown various pharmacological activities with unique advantages, especially in the aspect of antitumor. Neferine (Nef), a natural compound, extracted from green seed embryos of Lotus (Nelumbo nucifera Gaertn.) also exerts antitumor effects on cancers. In this study, the effects and mechanisms of Nef on epithelial-to-mesenchymal transition (EMT) process in non-small cell lung cancer (NSCLC) were evaluated. The results showed that Nef had the antitumor effects in vivo and in vitro. Nef significantly suppressed cell viability and induced apoptosis in NSCLC cells, with elevated reactive oxygen species and reduced BCL2/BAX ratio. Nef was also demonstrated to inhibit the invasion, metastasis and EMT process of NSCLC cells, and attenuate EMT-related changes of E-cadherin, N-cadherin and Vimentin at both transcriptional and translational levels. Moreover, we concluded that the inhibitory effects of Nef on EMT was achieved by targeting Rho-associated protein kinase 1, a protein mediating the process of EMT in various cancers. These results showed that Nef had a significant antitumor effect on NSCLC cells by inducing apoptosis and blocking EMT, providing the therapeutical prospect on NSCLC treatment. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Influence of Annealing Temperature on the Magnetic Properties of One-dimensional Diluted Magnetic Semiconductor Zn0.95Mn0.05O Tuning with Vacuum Atmospheric Annealing.
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Dong, Licheng, Liu, Chunmei, Shen, Zhe, Zhou, Bangfei, Zheng, Tianxiang, Li, Qiang, and Zhong, Yunbo
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DILUTED magnetic semiconductors , *MAGNETIC properties , *MAGNETIZATION measurement , *TEMPERATURE , *SCANNING electron microscopy - Abstract
Zn0.95Mn0.05O nanorods were synthesized via hydrothermal process and then treated with vacuum atmosphere annealed at different temperatures. Effects of annealing temperatures on microstructure, relative concentration of oxygen vacancy (VO), and magnetic properties were studied. SEM images clarified that the length and width of nanorods increased, while the aspect ratio decreased with increasing annealing temperatures. The elemental mappings showed that Mn was homogeneous without any Mn-rich wurtzite clusters. XRD and XPS results revealed that Mn ions had been introduced in wurtzite ZnO lattice and there were not any second phase observed. Furthermore, more VO had been produced in the samples as the annealing temperature increased. Finally, magnetization measurements implied that all of the Zn0.95Mn0.05O nanorods were ferromagnetism at room temperature. The saturated magnetization (Ms) of the unannealed samples was about 34.5 memu/g. When the nanorods were annealed under vacuum atmosphere, Ms became 35.5, 37.5, 50.5, and 71.6 memu/g, respectively, which corresponded to the annealing temperature of 100 ℃, 300 ℃, 500 ℃, and 700℃. The annealing temperature could significantly improve the magnetism of the products. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. Refinement of Eutectic Carbides in M2 High Speed Steel by Adjusting Magnetic Flux Density During Magnetic Controlled ESR Process.
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Guo, Yifeng, Qi, Wentao, Xia, Zhibin, Lin, Wenhao, Liu, Chunmei, Shi, Peijian, Li, Qiang, Shen, Zhe, Ding, Biao, Zheng, Tianxiang, and Zhong, Yunbo
- Subjects
MAGNETIC flux density ,TOOL-steel ,CARBIDES ,METAL refining ,TEMPERATURE distribution - Abstract
The current study examines the effect of magnetic flux density (MFD) on the morphology of the metal pool and the refinement of eutectic carbides in magnetic controlled electroslag remelting (MC-ESR, M2 high speed steel). When a transverse static magnetic field (TSMF) with a larger MFD was used, it was easier to obtain a shallower metal pool and finer eutectic carbides. These phenomena are explained by the smashing effect of the droplet neck (stronger at higher MFD values) induced by electromagnetic vibration, resulting in smaller/more dispersed droplets and thus a more uniform temperature distribution in the metal pool. Additionally, as MFD increased, the local solidification time (LST) decreased (0 to 140 mT) and the number of inclusions serving as heterogeneous nuclei for eutectic carbide formation increased (0 to 65 mT), resulting in a gradual size reduction of eutectic carbides. However, the refinement of eutectic carbides in MC-ESR must consider the above two factors comprehensively, and the MFD of applied TSMF need not be excessively large. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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15. Forming characteristics of a novel robot-based tube bending process.
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Sun, Zhenbiao, Liu, Chunmei, Guo, Xunzhong, Huang, Zushu, Zheng, Shuo, Cheng, Cheng, Tao, Jie, and Abd El-Aty, Ali
- Subjects
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TUBE bending , *TUBES , *STRAINS & stresses (Mechanics) , *AXIAL stresses , *FINITE element method , *INDUSTRIAL robots - Abstract
With the advancement of 'Industrial 4.0', industrial robots are becoming increasingly widespread. Thus, this study proposes a novel robot-based tube bending forming technology (RTBF) to increase the flexibility of manufacturing thin-walled complex-shaped tubes and to improve their quality. The forming mechanism and characteristics of the proposed technology are investigated using finite element modelling. Besides, the theoretical models for calculating the tube's inner and outer sides' equivalent stress are also presented. The obtained results showed that the bending die feeds in the tube axis direction while rotating in the novel robot-based tube bending forming, and the axial tensile stress T on the tube during the bending process is reduced. Comparing these results with the traditional rotary draw bending (RDB), the tensile stress and strain on the outer side of the bent tube and the thinning wall rate are both lower. On the other hand, the compressive stress and strain on the inner side of the bent tube and the wall thickening rate are higher in the robot-based tube bending process. The maximum cross-sectional distortion of a bent tube in the robot-based tube bending forming process remains unchanged with increasing bending angle and is always smaller than in the RDB process: the larger the bending angle, the more noticeable the difference. In summary, the robot-based tube bending forming technology significantly reduces the small diameter tube's wall thickness and cross-sectional distortion. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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16. Sound-induced flash illusion is modulated by the depth of auditory stimuli: Evidence from younger and older adults.
- Author
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Sun, Yawen, Zhou, Heng, Liu, Chunmei, Wang, Aijun, Yue, Chunlin, and Zhang, Ming
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AUDITORY perception ,OLDER people ,VISUAL perception - Abstract
Sound-induced flash illusion (SiFI) refers to an auditory dominance effect in which observers misperceive the number of visual flashes due to the simultaneous presentation of a different number of auditory beeps. Although the SiFI remains robust despite many factors, little is known about how the dominance of audition over vision changes as a function of spatial location in 3D space and how this corresponds with aging. In the present study, we recruited younger (18–26 years old) and older adults (60–76 years old) and presented visual stimuli in near space and auditory stimuli in far space (Vnear_Afar) or visual stimuli in far space and auditory stimuli in near space (Vfar_Anear), with the aim of exploring the effect of aging on spatial dominance in SiFI. The results showed that both participant groups exhibited a SiFI auditory dominance effect; however, older adults were more susceptible to illusions than younger adults. More importantly, for younger adults, when auditory stimuli were presented in far space, the accuracy and d' indicated that SiFI was significantly enhanced in the fission illusion, and the reaction time (RT) results showed that RT became longer in the fusion illusion. However, for older adults, the SiFI was not affected by the spatial location. Therefore, the present results reveal for the first time that the SiFI effect is modulated by the depth of auditory stimuli. Moreover, older adults were not susceptible to the depth dimension, thus showing age-related sensory decline and specifically showing a decreased ability to localize visual and auditory stimuli. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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17. Anisotropic mechanical responses and plastic deformation mechanisms of cadmium telluride under indentations.
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Xu, Chao, Zhang, Weilu, Hu, Mingdong, Zhang, Jing, Lang, Zhe, Li, Pengwei, Liu, Huaping, Wang, Pei, and Liu, Chunmei
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Molecular dynamic simulations were performed to investigate the indentations of CdTe crystal on (100), (110) and (111) surfaces. We found that the incipient plasticity, hardness, elastic recovery ratio and the structural evolution of CdTe during the indenting process depend strongly on the orientation of the indented surfaces due to the anisotropic nature of CdTe. The obtained load–displacement curves showed abrupt drops at critical indentation depths, indicating the occurrence of incipient plasticity. We found that the (001) plane yields first during the indenting process, followed by (110) plane, and the (111) plane yields last. For all the indented planes of CdTe, the incipient plasticity should be resulted from the nucleation and propagation of 1/2 < 110 > dislocations, which is consistent with the results from both experiments and the calculations of the generalized stacking fault energy. We found that the dislocation distribution under the indented (110) plane shows a twofold rotation symmetry, while those under the indented (111) and (001) planes show three- and fourfold rotation symmetry, respectively. The temperature effect on the indentation responses and structural evolution were also studied. This paper will not only answer the question about the orientation-dependent indentation responses of CdTe crystals, but also reveal the dislocation activities under the indentations in real time. The results of this paper are generally applicable to CdTe single-crystal systems and may provide reference data to improve the design and ultimately performance of the related CdTe-based devices. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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18. The clinicopathological characteristics and outcomes of IgA nephropathy with predominant lambda or kappa light-chain deposition.
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Sun, Shiren, Di, Wang, Li, Rong, Yang, Xiaoxia, Jia, Qin, Liu, Chunmei, and Ma, Feng
- Abstract
Purpose: IgA nephropathy (IgAN) patients with monoclonal light-chain deposition may be at potential risk of hematological progression. However, whether the clinical characteristics of the patients with predominant lambda or kappa light-chain deposition were consistent with monoclonal light-chain deposition is limited to anecdotes. Methods: We retrospectively studied patients in whom immunofluorescence showed IgA-alone deposits (n = 617) between January 2016 and January 2020. We divided the patients into two groups, the predominant lambda or kappa light-chain deposition group and the control group. Predominant lambda or kappa light-chain deposition was defined as the deposition intensity of kappa or lambda being + − and the other deposition intensity being ≥ 2 +. Results: Nineteen patients had predominant lambda or kappa light-chain deposition. The patients had a median age of 32 years. The median proteinuria was 0.9 g/day. The median eGFR was 79.8 ml/min per 1.73 m
2 . Two patients had a mildly abnormal FLC ratio, but serum immunofixation electrophoresis showed polyclonal immunoglobulin. Eighteen patients showed lambda light chain-dominated deposition. In electron microscopy, organized structures in dense deposits were not observed in all patients. Nine patients with proteinuria ≥ 1.0 g/day received corticosteroids and immunosuppressants. The median follow-up time was 21 months. The rate of proteinuria remission was 50%. The clinical and pathological characteristics and outcomes were not significantly different between the predominant lambda or kappa light-chain deposition group and the control group. Conclusion: The result for IgAN patients with predominant kappa/lambda light-chain deposition seemed to be the same as that of IgAN patients with light-chain codeposition. However, as this was a single-center study with a small size, further multicenter studies and long-term follow-up are needed to confirm our findings. [ABSTRACT FROM AUTHOR]- Published
- 2022
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19. Investigation on the influence of weld position on the deformation behavior of welded tube during free bending process.
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Cheng, Cheng, Pan, Chao, Bai, Xueshan, Liu, Chunmei, and Guo, Xunzhong
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DISTRIBUTION (Probability theory) ,WELDED joints ,TUBES ,WELDING ,HARDNESS testing - Abstract
The plastic deformation behavior of welded tube is affected by the non-uniform distribution of the mechanical properties of welded tube during the free bending process. To explore the influence of weld position on the forming quality and axis dimensional accuracy of welded tube, the free bending experiment and numerical simulation of welded tube were conducted in this paper. First, the principle of free bending was theoretically deduced and the stress distribution of bent tube was analyzed. Then, the hardness test and uniaxial tensile test were conducted to obtain the mechanical properties of weld zone and parent zone of welded tube. The material strength in the weld zone of welded tube is significantly higher than that in the parent zone. Finally, the free bending experiment and numerical simulation with different weld positions were carried out, and the influence of weld position on the bending radius, cross-sectional distortion, and wall thickness of bent tube was discussed. All these findings advance the insight into the free bending deformation behavior of welded tube and help to improve the forming quality of welded tubes and facilitate the application of free bending technology in welded tube. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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20. Long-term outcomes of IgA nephropathy patients with less than 25% crescents and mild proteinuria.
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Jia, Qing, Ma, Feng, Yang, Xiaoxia, Li, Linlin, Liu, Chunmei, Sun, Ruiling, Li, Rong, and Sun, Shiren
- Subjects
IGA glomerulonephritis ,PROTEINURIA ,IMMUNOSUPPRESSIVE agents ,KIDNEY physiology ,REGRESSION analysis - Abstract
Background: Whether immunosuppressive therapy in IgA nephropathy (IgAN) patients with less than 25% crescents (C1) and mild proteinuria can improve the renal outcome is still unclear. Methods: We recruited 140 IgAN patients with C1 and proteinuria < 1 g/24 h who received supportive care (n = 52) or steroid-based immunosuppressive therapy (n = 88) in Xijing Hospital from July 2008 to December 2016. The primary outcome was the rate of renal function decline. Results: The median of proteinuria was 575.5 mg/24 h, the fraction of crescents was 7% (5%, 12%) and follow-up time was 69.1 months. The rate of renal function decline [0.5 (− 1.5, 3.2) vs − 0.7 (− 3.5, 0.5) ml/min per 1.73 m
2 per year; P = 0.01] was slower in steroid-based immunosuppressive therapy group than supportive care group. Multivariate linear regression analyses showed steroid-based immunosuppressive therapy significantly slowed down the rate of renal function decline (β = − 0.220, 95% CI − 3.804 to − 0.449, P = 0.013) after adjusting age, sex, MAP, proteinuria, eGFR, M1, E1, S1, T1–2, the fraction of crescents and RASB. In the matched cohort, the rate of renal function decline was also slower in steroid-based immunosuppressive therapy group. The incidence of adverse events was similar between the two groups. Conclusion: Steroid-based immunosuppressive therapy may slow down the rate of renal function decline of IgAN patients with C1 and proteinuria ≤ 1 g/24 h. [ABSTRACT FROM AUTHOR]- Published
- 2022
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21. Real-time registration of remote sensing images with a Markov chain model.
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Song, Yinglei, Qu, Junfeng, and Liu, Chunmei
- Abstract
The automatic registration of different remote sensing images of the same scene is an important problem in the processing of remote sensing images. Such images usually have different resolutions and computing an accurate registration of them in real time is thus often a challenging task. In this paper, a new statistical approach is developed for the accurate and efficient registration of two remote sensing images with different resolutions. The proposed approach utilizes a statistical model to evaluate the probability for each possible mapping between the two images and computes the one with the maximum probability for registration. Similar to most of the state-of-the-art methods for remote sensing image registration, the proposed approach assumes the existence of an affine transformation between the images to be registered. The registration is performed in three stages. In the first stage, the pixels in each image are efficiently partitioned into two sets with the Otsu's algorithm and four approximate equations for the parameters in the affine transformation are established. In the second stage, pixels in both images with significant edge geometric features are selected for potential pixel matching. In the third stage, based on the four approximate equations generated in the first stage, an Markov Chain Model-based method is used to efficiently compute the matching that can pair the selected pixels with the maximum likelihood. The parameters of the affine transformation can be determined from the pixel pairs with a least square regression approach. Experimental results on a number of pairs of remote sensing images show that this approach can generate registration results more accurate than those obtained with a few state-of-the-art approaches. In addition, real-time evaluation also shows that the approach is computationally efficient and can be used in real-time applications for remote sensing image processing. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
22. Assessment of normalized cerebral blood flow and its connectivity with migraines without aura during interictal periods by arterial spin labeling.
- Author
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Zhang, Di, Huang, Xiaobin, Mao, Cunnan, Chen, Yuchen, Miao, Zhengfei, Liu, Chunmei, Xu, Chenjie, Wu, Xinying, and Yin, Xindao
- Subjects
FRONTAL lobe ,PARIETAL lobe ,CEREBRAL circulation ,MIGRAINE ,EPILEPSY ,BASAL ganglia ,OCCIPITAL lobe ,MAGNETIC resonance imaging ,RADIONUCLIDE imaging ,QUESTIONNAIRES ,SEIZURES (Medicine) ,VISION disorders ,PERFUSION - Abstract
Background: Migraine constitutes a global health burden, and its pathophysiology is not well-understood; research evaluating cerebral perfusion and altered blood flow between brain areas using non-invasive imaging techniques, such as arterial spin labeling, have been scarce. This study aimed to assess cerebral blood flow (CBF) and its connectivity of migraine. Methods: This study enrolled 40 patients with episodic migraine without aura (MwoA), as well as 42 healthy patients as control (HC). Two groups of normalized CBF and CBF connectivity were compared, and the relationship between CBF variation and clinical scale assessment was further evaluated. Results: In comparison to HC subjects, MwoA patients exhibited higher CBF in the right middle frontal orbital gyrus (ORBmid.R) and the right middle frontal gyrus, while that in Vermis_6 declined. The increased CBF of ORBmid.R was positively correlated with both the Visual Light Sensitivity Questionnaire-8 (VLSQ-8) and the monthly attack frequency score. In MwoA, significantly decreased CBF connectivity was detected between ORBmid.R and the left superior frontal gyrus, the right putamen, the right caudate, as well as the right angular gyrus. In addition, increased CBF connectivity was observed between the left calcarine cortex and ORBmid.R. Conclusions: Our results indicate that migraine patients exhibit abnormalities in regional CBF and feature CBF connection defects at the resting state. The affected areas involve information perception, information integration, and emotional, pain and visual processing. Our findings might provide important clues for the pathophysiology of migraine. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
23. Sensing behavior of Cu-embedded C3N monolayer upon dissolved gases in transformer oil: a first-principles study.
- Author
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Cao, Wen, Liu, Chunmei, Jia, Pengfei, and Cui, Hao
- Published
- 2021
- Full Text
- View/download PDF
24. Altered amygdala effective connectivity in migraine without aura: evidence from resting‐state fMRI with Granger causality analysis.
- Author
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Huang, Xiaobin, Zhang, Di, Wang, Peng, Mao, Cunnan, Miao, Zhengfei, Liu, Chunmei, Xu, Chenjie, Yin, Xindao, and Wu, Xinying
- Subjects
FRONTAL lobe ,TEMPORAL lobe ,PAIN ,MIGRAINE ,FUNCTIONAL connectivity ,MAGNETIC resonance imaging ,DISEASE duration ,AMYGDALOID body ,HEADACHE ,CAUSALITY (Physics) - Abstract
Background: Granger causality analysis (GCA) has been used to investigate the pathophysiology of migraine. Amygdala plays a key role in pain modulation of migraine attack. However, the detailed neuromechanism remained to be elucidated. We applied GCA to explore the amygdala-based directional effective connectivity in migraine without aura (MwoA) and to determine the relation with clinical characteristics. Methods: Forty-five MwoA patients and forty age-, sex-, and years of education-matched healthy controls(HCs) underwent resting-state functional magnetic resonance imaging (fMRI). Bilateral amygdala were used as seed regions in GCA to investigate directional effective connectivity and relation with migraine duration or attack frequency. Results: MwoA patients showed significantly decreased effective connectivity from right amygdala to right superior temporal gyrus, left superior temporal gyrus and right precentral gyrus compared with HCs. Furthermore, MwoA patients demonstrated significantly decreased effective connectivity from the left amygdala to the ipsilateral superior temporal gyrus. Also, MwoA patients showed enhanced effective connectivity from left inferior frontal gyrus to left amygdala. Effective connectivity outflow from right amygdala to right precentral gyrus was negatively correlated to disease duration. Conclusions: Altered directional effective connectivity of amygdala demonstrated that neurolimbic pain networks contribute to multisensory integration abnormalities and deficits in pain modulation of MwoA patients. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. Treatment for IgA nephropathy with stage 3 or 4 chronic kidney disease: low-dose corticosteroids combined with oral cyclophosphamide.
- Author
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Ma, Feng, Yang, Xiaoxia, Zhou, Meilan, Bai, Ming, Zhao, Lijuan, Li, Li, Dong, Ruijuan, Liu, Chunmei, Li, Rong, and Sun, Shiren
- Published
- 2020
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26. Aquaporin 1 alleviates acute kidney injury via PI3K-mediated macrophage M2 polarization.
- Author
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Liu, ChunMei, Li, BoHui, Tang, KaiHong, Dong, XueNing, Xue, LongGe, Su, Guangming, and Jin, Yingyu
- Subjects
- *
ACUTE kidney failure , *KIDNEY injuries , *TUMOR necrosis factors , *EPITHELIAL cells , *BLOOD proteins - Abstract
Background: Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is associated with an abnormal immune response. Accumulating evidence has demonstrated that aquaporin 1 (AQP1) prevents kidney tissue injury in LPS-induced AKI by mediating immune response. However, the underlying mechanisms remain obscure. Macrophages as immune cells with multiple phenotypes are important mediators in tissue homeostasis and host defense. We propose that macrophage polarization is implicated in AQP1-mediated immune response. Methods: Herein we established sepsis-induced AKI model rats through intraperitoneal injection of LPS into Wistar rats to reveal immune mechanism of damage. We also used LPS-induced mouse RAW264.7 cells to elucidate the molecular mechanism of macropage polarization. Results: Histopathology showed that renal tubular epithelial cells in the model group were swollen, inflammatory exudation was obvious and the inflammatory factors, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were increased. Western blotting showed PI3K was upregulated in the model group. Serum creatinine and urea nitrogen increased after LPS injection. Renal AQP1 mRNA is downregulated and serum AQP1 protein increased first and then decreased in LPS-induced AKI rats. M2 macrophage markers (Arg-1, CD206) were increased in repair stage. In addition, treatment of murine macrophages (RAW264.7) with AQP1 siRNA resulted in decreased PI3K activation and M2 polarization, but increased IL-6 and TNF-α. Moreover, inhibiting PI3K with wortmannin imitated the results of AQP1 silencing. Conclusions: Macrophage M2 polarization is likely the cellular mechanism underlying the anti-AKI property of AQP1, and PI3K activation is involved in the AQP1-induced M2 phenotype switch. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
27. Altered lateral geniculate nucleus functional connectivity in migraine without aura: a resting-state functional MRI study.
- Author
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Zhang, Di, Huang, Xiaobin, Su, Wen, Chen, Yuchen, Wang, Peng, Mao, Cunnan, Miao, Zhengfei, Liu, Chunmei, Xu, Chenjie, Yin, Xindao, and Wu, Xinying
- Subjects
MIGRAINE diagnosis ,BRAIN mapping ,CEREBELLUM ,EMOTIONS ,FRONTAL lobe ,MAGNETIC resonance imaging ,MIGRAINE ,OCCIPITAL lobe ,QUESTIONNAIRES ,SELF-control ,THALAMUS ,VISION disorders ,THREE-dimensional imaging ,SYMPTOMS - Abstract
Objectives: To investigate the structural and functional connectivity changes of lateral geniculate nucleus (LGN) and their relationships with clinical characteristics in patients without aura. Methods: Conventional MRI, 3D structure images and resting state functional MRI were performed in 30 migraine patients without aura (MwoA) and 22 healthy controls (HC). The lateral geniculate nucleus volumes and the functional connectivity (FC) of bilateral lateral geniculate nucleus were computed and compared between groups. Results: The lateral geniculate nucleus volumes in patient groups did not differ from the controls. The brain regions with increased FC of the left LGN mainly located in the left cerebellum and right lingual gyrus in MwoA compared with HC. The increased FC of right LGN located in left inferior frontal gyrus in MwoA compared with HC. The correlation analysis showed a positive correlation between VLSQ-8 score and the increased FC of left cerebellum and right lingual gyrus. Conclusions: Photophobia in MwoA could be mediated by abnormal resting state functional connectivity in visual processing regions, the pain perception regulatory network and emotion regulation network. This result is valuable to further understanding about the clinical manifestation and pathogenesis of migraine. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
28. Magnetic field–dependent microstructure evolution and magnetic property of Fe–6.5 Si–0.05 B alloy during solidification.
- Author
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Liu, Chunmei, Zhong, Yunbo, Shen, Zhe, Dong, Licheng, Zheng, Tianxiang, Ren, Weili, Lei, Zuosheng, and Ren, Zhongming
- Published
- 2019
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29. Aquaporin-1 attenuates macrophage-mediated inflammatory responses by inhibiting p38 mitogen-activated protein kinase activation in lipopolysaccharide-induced acute kidney injury.
- Author
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Li, Bohui, Liu, Chunmei, Tang, Kaihong, Dong, Xuening, Xue, Longge, Su, Guangming, Zhang, Wenzheng, and Jin, Yingyu
- Subjects
- *
MACROPHAGE inflammatory proteins , *MITOGEN-activated protein kinases , *ACUTE kidney failure , *INFLAMMATORY mediators , *WESTERN immunoblotting , *GENE silencing - Abstract
Objective: This study was designed to investigate the role of AQP1 in the development of LPS-induced AKI and its potential regulatory mechanisms in the inflammatory responses of macrophages. Methods: Male Wistar rats were injected intraperitoneally with LPS, and biochemical and histological renal damage was assessed. The levels of inflammatory mediators, macrophage markers and AQP1 in blood and kidney tissues were assessed by ELISA. RTPCR was used to assess changes in the relative levels of AQP1 mRNA induced by LPS. Western blot and immunofluorescence analyses were performed to assay the activation of the p38 MAPK and NF-κB pathways, respectively. The same detection methods were used in vitro to determine the regulatory mechanisms underlying AQP1 function. Results: AQP1 mRNA levels were dramatically decreased in AKI rats following the increased expression of inflammatory factors. In vitro experiments demonstrated that silencing the AQP1 gene increased inflammatory mediator secretion, altered the classical activation of macrophages, greatly enhanced the phosphorylation of p38 and accelerated the translocation of NF-κB. Furthermore, these results were blocked by doramapimod, a p38 inhibitor. Therefore, these effects were mediated by the increased phosphorylation of p38 MAPK. Conclusion: Our results suggest that altered AQP1 expression may be associated with the development of inflammation in AKI. AQP1 plays a protective role in modulating acute renal injury and can attenuate macrophage-mediated inflammatory responses by downregulating p38 MAPK activity in LPS-induced RAW264.7 cells. The pharmacological targeting of AQP1-mediated p38 MAPK signalling may provide a novel treatment approach for AKI. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
30. Altered functional connectivity of the red nucleus and substantia nigra in migraine without aura.
- Author
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Huang, Xiaobin, Zhang, Di, Chen, Yuchen, Wang, Peng, Mao, Cunnan, Miao, Zhengfei, Liu, Chunmei, Xu, Chenjie, Wu, Xinying, and Yin, Xindao
- Subjects
MIGRAINE diagnosis ,DIAGNOSIS of brain abnormalities ,BRAIN mapping ,BRAIN stem ,CEREBELLUM ,COGNITIVE testing ,FRONTAL lobe ,MAGNETIC resonance imaging ,NEUROPSYCHOLOGICAL tests ,MIGRAINE ,PARIETAL lobe ,SYMPTOMS ,EDUCATIONAL attainment ,DISEASE duration ,NEURAL pathways - Abstract
Background: Functional connectivity (FC) has been used to investigate the pathophysiology of migraine. Accumulating evidence is pointing toward malfunctioning of brainstem structures, i.e., the red nucleus (RN) and substantia nigra (SN), as an important factor in migraine without aura (MwoA). We aimed to identify atypical FC between the RN and SN and other brain areas in patients with MwoA and to explore the association between RN and SN connectivity changes and performance on neuropsychological tests in these patients. Methods: Resting-state functional magnetic resonance imaging (fMRI) data were obtained from 30 patients with MwoA and 22 age-, sex-, and years of education-matched healthy controls (HC). The FC of the brainstem structures was analyzed using a standard seed-based whole-brain correlation method. The results of the brainstem structure FC were assessed for correlations with other clinical features. Results: Patients with MwoA exhibited reduced left RN-based FC with the left middle frontal gyrus, reduced right RN-based FC with the ipsilateral superior parietal lobe, and increased FC with the ipsilateral cerebellum. Additionally, patients with MwoA demonstrated significantly decreased right SN-based FC with the right postcentral gyrus, left parietal lobule, and left superior frontal gyrus. Hypo-connectivity between the right SN and right postcentral gyrus was negatively correlated with disease duration (r = − 0.506, P = 0.004). Additionally, increased connectivity of the right RN to the ipsilateral cerebellar lobes was positively correlated with the Headache Impact Test-6 scores (r = 0.437, P = 0.016). Conclusions: The present study suggested that patients with MwoA have disruption in their RN and SN resting-state networks, which are associated with specific clinical characteristics. The changes focus on the regions associated with cognitive evaluation, multisensory integration, and modulation of perception and pain, which may be associated with migraine production, feedback, and development. Taken together, these results may improve our understanding of the neuropathological mechanism of migraine. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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31. A novel method to reduce the distortion of ridged rectangular tube in H-typed rotary draw bending.
- Author
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Liu, Chunmei, Liu, Yuli, and Sun, Hong
- Subjects
- *
TUBES , *TUBE bending - Abstract
Ridged rectangular tubes are widely utilized in microwave equipment as waveguides. However, cross-sectional deformation easily occurs when a ridged rectangular tube is bent. Especially for H-typed bending, the deformation of ridge grooves cannot be controlled effectively by using the current bending tools. Therefore, a novel method adding fillers in ridge grooves to reduce the distortion is presented in this paper. According to this method, a three-dimensional finite element model of H-typed rotary draw bending of H96 brass double-ridged rectangular tube with ridge groove fillers was established, and then the reliability of the model and new method was verified by the experiment. It is found that when fillers are used, cross-sectional deformation significantly decreases, especially the height deformation and the spacing deformation of ridge grooves. Moreover, an obvious decrease in the distortion difference between different sections is observed, which means the distribution of deformation ratios along the bending direction is more uniform. Through further validation with a single-ridged rectangular tube, it shows that the novel method is feasible and ridge groove fillers are strongly recommended to be introduced in the bending of different ridged rectangular tubes. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
32. Molecular recognition of cyclodecapeptides to ibuprofen and naproxen enantiomers: a theoretical study.
- Author
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Li, Xue, Zhu, Yanyan, Liu, Chunmei, Lin, Xincheng, Zhang, Wenjing, and Tang, Mingsheng
- Subjects
MOLECULAR recognition ,IBUPROFEN ,ENANTIOMERS ,CYCLIC peptides ,HOST-guest chemistry ,QUANTUM chemistry - Abstract
Cyclopeptide derivatives have attracted great interest in host-guest chemistry during the past decades. In this work, four cyclopeptides including one cyclodecapeptide (CDP) and three modified CDPs (M-CDP involves I-CDP, E-CDP, and H-CDP) are adopted as hosts to differentiate the four guests of the amphetamine (AP) and ibuprofen (IP) enantiomers using a proposed integrated computation protocol. The obtained results demonstrated that the guests of AP and IP enantiomers could be recognized by different cyclopeptides using the certain optimized quantum chemistry methods. Specifically, the AP or IP enantiomers might be identified by the corresponding cyclopepitdes in the five pairs of the inclusion complexes associated with the large differences of binding energies of hosts with guests, that is, the two of H-CDP/AP and H-CDP/IP by B3LYP, the two of I-CDP/IP and H-CDP/IP by CAM-B3LYP, and the other one of I-CDP/IP by M06-2X, which are mainly determined by their corresponding stable conformations, electronic properties, and favorable interactions. The intermolecular hydrogen bonds and NBO analyses of the inclusion complexes further suggest the corresponding differences of binding energies. The visual nonbonded weak interactions for the studied systems gave the reasons why the AP and IP enantiomers are identified by the corresponding cyclopeptides. Molecular dynamics simulated results further support the above conclusions. The investigation provides detailed information at a molecular level about the recognition of the two chiral drug molecules by the four cyclodecapeptides. The integrated computation protocol proposed in this work provides people a feasible way to study interaction of hosts and guests, molecular recognition, and chiral separation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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33. Influence of different mandrels on cross-sectional deformation of the double-ridge rectangular tube in rotary draw bending process.
- Author
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Liu, Chunmei, Liu, Yuli, and Yang, He
- Subjects
- *
ARBORS & mandrels , *MICROWAVE transmission lines , *POLYVINYL chloride , *FINITE element method , *DEFORMATIONS (Mechanics) - Abstract
Cross-sectional deformation of the double-ridged rectangular tube inevitably occurs in the rotary draw bending process. It has serious effect on the characteristic of microwave transmission and restricts the quality and performance of tube. Different mandrels play different roles in the bending process, so the rigid and polyvinyl chloride (PVC) mandrels are applied in the E-typed and H-typed rotary draw bending of double-ridged rectangular tube to study their influence on the cross-sectional deformation. Based on the platform of ABAQUS/Explicit, the three-dimensional finite element models for E-typed and H-typed rotary draw bending of H96 brass double-ridged rectangular tube with rigid and PVC mandrels have been established and validated by experiment. Results show that whether in the E-typed or H-typed bending, the PVC mandrel has better inhibitory effect on the cross-sectional long-side deformation δ , short-side deformation δ , and spacing deformation between the bottom of ridge grooves δ of the tube. And the PVC mandrel can be more helpful to reduce the width deformation of ridge grooves of the tube in H-typed bending. The rigid mandrel can restrain the width expansion deformation of outer ridge groove of the tube more effectively in E-typed bending. However, whether using the rigid or PVC mandrel, the width shrinkage deformation of inner ridge groove of the tube in E-typed bending is less affected by the type of mandrels. And the width of two ridge grooves on sidewalls of the tube in H-typed bending also has the obvious shrinkage deformation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
34. Impact of springback on the cross-sectional deformation of H96 brass double-ridged rectangular tube in E-typed rotary draw bending.
- Author
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Zheng, Xusheng, Liu, Yuli, Liu, Chunmei, and Yang, He
- Subjects
SPRINGBACK (Elasticity) ,DEFORMATIONS (Mechanics) ,TUBES ,BENDING (Metalwork) ,FINITE element method - Abstract
Cross-sectional deformation is one of the critical factors that affect the forming accuracy of double-ridged rectangular tube (DRRT) in E-typed rotary draw bending (RDB). In the forming process, springback is inevitable and it has a direct impact on the cross-sectional deformation. Based on ABAQUS platform, three-dimensional finite element (3D-FE) models for bending and springback of H96 brass DRRT in E-typed RDB were established. With the models, the impact of springback on the cross-sectional deformation was studied. Results show that after springback, the deformation of cross-sectional height and two ridge grooves spacing increase in cores-support zone while decrease in no-cores-support zone. The impact of springback on width deformation is not significant. The maximum values of cross-sectional height deformation and two ridge grooves spacing deformation from 0° to 30° become larger after springback, while the change rules of these two from 30° to 90° are reversed. What's more, the maximum value of width deformation from 0° to 60° becomes larger after springback while that of outer ridge groove width deformation becomes smaller, and these two from 60° to 90° both have the reversed change rules as well. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
35. Timosaponin B-II ameliorates scopolamine-induced cognition deficits by attenuating acetylcholinesterase activity and brain oxidative damage in mice.
- Author
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Zhao, Xu, Liu, Chunmei, Qi, Yu, Fang, Lina, Luo, Jie, Bi, Kaishun, and Jia, Ying
- Subjects
- *
ALZHEIMER'S disease treatment , *SAPONINS , *ACETYLCHOLINESTERASE inhibitors , *OXIDATIVE stress , *COGNITION disorders treatment , *SCOPOLAMINE , *ASPARAGACEAE , *BRAIN physiology , *THERAPEUTICS , *PREVENTION - Abstract
Timosaponin B-II (TB-II) is a main active saponin isolated from the rhizome of Anemarrhena asphodeloides Bge., which is widely used in traditional Chinese medicine. In this study, the effect of TB-II on learning and memory was investigated in a scopolamine-induced mouse model of Alzheimer's disease. The results of behavioral tests indicated that TB-II significantly increased the spontaneous alternation in the Y-maze test, and reversed the shortening of step-through latency induced by scopolamine in the passive avoidance test, showing protective effects on short-term and working memory. In the Morris water maze test, TB-II reduced the escape latency time in the training trial, and increased the swimming time in the target quadrant in the probe trial. Biochemical data demonstrated that TB-II significantly inhibited acetylcholinesterase (AChE) activity in the cerebral cortex and hippocampus of mice. Moreover, TB-II markably attenuated the reduction in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, and decreased malondialdehyde (MDA) levels, which are key biomarkers of brain oxidative stress. These results indicated that TB-II offers protection against scopolamine-induced deficits in learning and memory, possibly by inhibiting AChE and preventing oxidative stress damage. The findings suggested that TB-II has a potential therapeutic effect on cognitive and behavioral impairment. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. Evaluations of AMBER force field parameters by MINA approach for copper-based nucleases.
- Author
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Liu, Chunmei, Zhang, Bin, Zhu, Yanyan, and Tang, Mingsheng
- Subjects
- *
NUCLEASES , *MOLECULAR force constants , *COPPER compounds , *MOLECULAR dynamics , *CHEMICAL bond lengths , *BOND angles , *MOLECULAR structure - Abstract
We describe the development of the AMBER force field parameters for 46 nucleases involving most kinds of copper nucleases with high DNA affinities and specificities by MINA approach that could evaluate accurate force constants for batch bonds/angles on the basis of energies of three adjacent lengths/angles geometries. The molecular mechanics (MM) and molecular dynamic simulations on adducts of the 21 representative copper-based nucleases with DNA are in excellent agreement with those of experimental results. Furthermore, to validate the evaluated parameters, the studied structures performed frequency analysis together with normal mode calculations in quantum mechanics and MM calculations. The force field parameters evaluated in this work provide an extension of AMBER force field, and the results of molecular dynamics simulations of adduct of copper nuclease and duplex DNA illustrate the potential utility of these parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
37. Lipid desaturation in prokaryotic pathway abates the high-oleic phenotype of FAD2-silenced tobacco at lower temperature.
- Author
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Zhang, Lulu, Lu, Heshu, Liu, Chunmei, Xue, Feiyan, Yang, Jing, Ma, Lanqing, and Yang, Mingfeng
- Abstract
The stability of the high-oleic characteristic of tobacco ( Nicotiana tabacum) transformants obtained by silencing of microsomal Ω-6 desaturase (FAD2) was investigated when grown at low temperature. Results showed that oleic acid content in total leaf lipids, individual leaf lipids and total seed lipids of transformants decreased drastically at low temperature, with a corresponding increase of polyunsaturated fatty acid contents. The decrease of oleate was caused by neither the restoration of FAD2 transcripts nor the disappearance of small interference RNA. A significant increase of hexadecadienoic acid and hexadecatrienoic acid was observed in MGDG (monogalactosyldiacylglycerol) of transformants grown at lower temperature. Hexadecadienoic and hexadecatrienoic acids, typical fatty acids in MGDG, are produced through the activity of Ω-6 desaturase in plastids (FAD6). The significant increase of Hexadecadienoic and hexadecatrienoic acids suggested the involvement of FAD6 and/or other desaturases in the lipid desaturation of transgenic plants under lower temperature, leading to a significant decrease of oleate in plant cells. These results suggested that the activities of plastidic desaturases must be, at least partially, responsible for the instability of the high-oleic characteristic of FAD2-silenced plants. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
38. Rapid Annotation of Non-coding RNA Structures with a Parameterized Filtering Approach.
- Author
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Song, Yinglei, Qu, Junfeng, and Liu, Chunmei
- Published
- 2015
- Full Text
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39. DFT study on reaction mechanisms of cyclic dipeptide generation.
- Author
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Li, Yue, Li, Fangfang, Zhu, Yanyan, Li, Xue, Zhou, Ziyuan, Liu, Chunmei, Zhang, Wenjing, and Tang, Mingsheng
- Subjects
AMINO acids ,VIBRATIONAL redistribution (Molecular physics) ,OXIDATION-reduction reaction ,DIPEPTIDES ,HYDROGEN - Abstract
In this work, three possible reaction pathways (Path 1, Path 2 and Path 3) for the generation process of cyclic dipeptide from amino acid have been investigated in detail using density functional theory. Path 1 and Path 2 are the intramolecular reaction processes, while Path 3 involves the intermolecular reaction process that assisted with water molecule. Our calculated results indicate that Path 3 is more energy favorable than Path 1 and Path 2. There are four steps in Path 3 proceed from the amino acid to cyclic dipeptide. The first step is two adjacent amino acids to form precursor of dipeptide, the second step is the removal of water molecule of precursor of dipeptide for the formation of the linear dipeptide, the third step is generation of precursor of cyclic dipeptide associated with other hydrogen atom transfer, and the last step is another dehydration process to generate the final product of cyclic dipeptide. Moreover, the obtained results indicate that the generation mechanisms of different cyclic dipeptides are similar, and the energy barrier of the rate-determined step influenced somewhat by the hydrophilic or hydrophobic group linked to the C atom. Additionally, the potential energy profiles suggest that the generation reactions of the studied nine cyclic dipeptides are exothermic processes. The detailed mechanisms should be helpful for people to understanding the title reaction at the molecular level, and the proposed novel intermolecular process might provide valuable insights on rational improve reaction condition for this type of reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
40. Theoretical study of binding affinity for diamidine with DNA.
- Author
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Song, Chen, Zhang, Xuening, Li, Fangfang, Zhu, Yanyan, Liu, Chunmei, Li, Xue, Li, Yue, Zhang, Wenjing, Wei, Donghui, and Tang, Mingsheng
- Subjects
PENTAMIDINE ,DNA analysis ,HETEROCHAIN polymers ,MOLECULAR structure ,DRUG development - Abstract
Diamidine molecules, which have been recognized as the powerful gene drug candidates over the past decades, can bind in the DNA minor groove, inhibit the duplication of morbid sequences, and fight against a number of human and animal diseases. In this paper, on the basis of the binding models of a series of diamidines with DNA, the important influencing factors for the binding affinity of diamidines with DNA were systematically analyzed. The obtained results demonstrated that the curvature, length, distal group, and heteroaromatic ring of diamidine are four important factors, which could influence their binding affinities. Specifically, the better the curvature of the diamidine fits DNA minor groove, the higher the binding affinity is; increasing the molecular length within a certain range can make the binding affinity higher; changing the distal group of diamidine from amidino to imidazole or pyrimidine is favorable for improving the corresponding binding affinity; and the introduction of central heteroaromatic rings of diamidine molecules influences their binding affinities. One diamidine (named as DB103d) with ideal DNA binding affinity validates the four important factors proposed in the present work. The results obtained in this work might be helpful for the design of new efficient diamidine-based drug candidates. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
41. Quasi-optimal complexity of adaptive finite element method for linear elasticity problems in two dimensions.
- Author
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Liu, Chunmei, Zhong, Liuqiang, Shu, Shi, and Xiao, Yingxiong
- Subjects
- *
COMPUTATIONAL complexity , *ADAPTIVE computing systems , *FINITE element method , *ELASTICITY , *MATHEMATICAL bounds - Abstract
This paper introduces an adaptive finite element method (AFEM) using the newest vertex bisection and marking exclusively according to the error estimator without special treatment of oscillation. By the combination of the global lower bound and the localized upper bound of the posteriori error estimator, perturbation of oscillation, and cardinality of the marked element set, it is proved that the AFEM is quasi-optimal for linear elasticity problems in two dimensions, and this conclusion is verified by the numerical examples. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
42. Short-term assessment of BCR repertoires of SLE patients after high dose glucocorticoid therapy with high-throughput sequencing.
- Author
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Shi, Bin, Yu, Jiang, Ma, Long, Ma, Qingqing, Liu, Chunmei, Sun, Suhong, Ma, Rui, and Yao, Xinsheng
- Published
- 2016
- Full Text
- View/download PDF
43. Multi-layers Segmentation Based Adaptive Binarization for Text Extraction in Scanned Card Images.
- Author
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Liu, Chunmei
- Published
- 2014
- Full Text
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44. Theoretical study on binding models of copper nucleases containing pyridyl groups to DNA.
- Author
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Zhang, Xuening, Tang, Mingsheng, Li, Fangfang, Zhu, Yanyan, Liu, Chunmei, Zhang, Wenjing, and Wei, Donghui
- Subjects
NUCLEASES ,DNA ,COPPER ,HYDROGEN bonding interactions ,COPPER ions ,DISTRIBUTION (Probability theory) - Abstract
Molecular dynamic simulations have been performed to investigate the DNA binding affinities and cleavage activities of a new class of copper nucleases with similar ligand structures, including Cu(pzdpy)
2+ , Cu(hpzpy)2+ , Cu(pmea)2+ , Cu(pmap)2+ , Cu(tepa)2+ and Cu(tpa)2+ , in this present study. The obtained results reveal that the five copper nucleases bind to DNA in the minor groove, while the favorable binding sites for Cu(tepa)2+ locate in the DNA major groove. Analyses of binding free energies, all possible hydrogen bonds and favorable interactions between copper nucleases and DNA suggest that DNA binding affinities of the six copper nucleases are in the order of Cu(pzdpy)2+ > Cu(hpzpy)2+ > Cu(pmea)2+ > Cu(tepa)2+ > Cu(tpa)2+ > Cu(pmap)2+ , which is good agreement with the experimental results. Meanwhile, the simulated results demonstrated that significant difference in frequency distribution of the DNA helical parameters was observed between the unbound B-DNA and the bound DNA by the copper nucleases, which causes the inhibition of transcription and replication. Furthermore, RDF analyses suggest that the activities of the studied copper nucleases decrease in the order of Cu(pzdpy)2+ , Cu(pmea)2+ , Cu(hpzpy)2+ , Cu(tpa)2+ , Cu(pmap)2+ and Cu(tepa)2+ , consisting with the experimental results. The present study provides detailed information to help us understand a new congeneric class of copper nucleases with different nuclease properties. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
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45. Effect of particle conductivity on Fe-Si composite electrodeposition.
- Author
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Long, Qiong, Zhong, Yunbo, Zheng, Tianxiang, and Liu, Chunmei
- Published
- 2014
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46. A Graph Approach to Bridge the Gaps in Volumetric Electron Cryo-microscopy Skeletons.
- Author
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N sr, Kamal Al, Liu, Chunmei, Rwebangira, Mugizi Robert, and Burge, Legand L. Iii
- Published
- 2013
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47. Vehicle Queue Length Measurement Based on a Modified Local Variance and LBP.
- Author
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Chai, Qin, Cheng, Cheng, Liu, Chunmei, and Chen, Hongzhong
- Published
- 2013
- Full Text
- View/download PDF
48. Research on the Selection between Absolute and Intensity-Based Limits of CO2 Emissions.
- Author
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Liu, Chunmei, Duan, Maosheng, and Pang, Tao
- Published
- 2012
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49. In Silico Prediction of Post-translational Modifications.
- Author
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Liu, Chunmei and Li, Hui
- Published
- 2011
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50. An Ontology-Based Framework Model for Trustworthy Software Evolution.
- Author
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Li, Ji, Liu, Chunmei, and Li, Zhiguo
- Abstract
In this paper, a framework model for trustworthy software evolution is constructed. It could not only solve semantic problems but also guide the dynamic evolution of service composition. First of all, it adopts a method of ontology space to solve the interactive problem among users, system and environment. Then, a set of pre-defined rules are used to evaluate the credibility of software behavior and the necessity for self-adjustment. According to these results, we make adjustment, reconfiguration and revision to the software in software life cycle, from rule guidance in micro-level to man-machine cooperation in macro-level. Finally, the instances and test results prove the proposed framework model to be effective and feasible. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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