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Da QC, He LH, Zhang BZ, Zuo PJ, Li LP. [Progress in health effects and measurement standards of ultraviolet radiation in the workplace]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2022; 40:466-470. [PMID: 35785906 DOI: 10.3760/cma.j.cn121094-20210826-00428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultraviolet radiation affects human health. On the one hand, moderate amounts of UV radiation can promote human health and have the effect of promoting vitamin D production; but on the other hand, excessive UV radiation can also cause adverse effects on human skin and eyes, such as causing skin photoaging, skin cancer, electrophthalmia and cataracts to occur. Therefore, the measurement of ultraviolet radiation is extremely important. This paper mainly reviews the health effects of ultraviolet radiation and the progress of measurement standards in the workplace, and puts forward suggestions on the revision of the existing standards from five aspects including use new measuring instruments and methods, improve the existing measuring instruments, specify the number of measurements, expand the scope of application of the standards and consider the influence of the sun on the measurement of artificial ultraviolet radiation, so as to provide reference for the revision of new standards.
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Affiliation(s)
- Q C Da
- School of Public Health/Medical College, Shantou University, Shantou 515041, China
| | - L H He
- School of Public Health, Peking University, Beijing 100191, China
| | - B Z Zhang
- Department of Astronomy, Beijing Normal University, Beijing 100875, China
| | - P J Zuo
- School of Public Health/Medical College, Shantou University, Shantou 515041, China
| | - L P Li
- School of Public Health/Medical College, Shantou University, Shantou 515041, China
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Duan XF, He LH, Shang XB, Yue J, Ma Z, Chen CG, Zhang C, Qu DW, Jiang HJ. [Clinical value of routine contrast esophagram in the diagnosis of anastomotic leakage for three-incision esophagectomy with cervical anastomosis]. Zhonghua Wai Ke Za Zhi 2022; 60:461-465. [PMID: 35359088 DOI: 10.3760/cma.j.cn112139-20210908-00427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Objective: To examine the clinical value of routine contrast esophagram (RCE) for the diagnosis of anastomotic leakage (AL) after three-incision esophagectomy with cervical anastomosis. Methods: Clinical data of 1 022 patients with esophageal cancer who underwent McKeown three-incision esophagectomy with cervical anastomosis from January 2015 to December 2019 at Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute were analyzed retrospectively. There were 876 males and 146 females, aging(M(IQR)) 48(16) years (range: 36 to 84 years). There were 253 patients (24.8%) with neoadjuvant therapy, and 817 patients (79.9%) with minimally invasive esophagectomy. According to the diagnosis and treatment habits of the attending surgeons, 333 patients were included in the RCE group, and RCE was performed on the 7th day postoperative, while 689 patients were included in the non-RCE group, and RCE was performed when the patients had suspicious symptoms. Taking clinical symptoms, RCE, CT, endoscopy and other methods as reference to the diagnosis of AL, the sensitivity and specificity were used to analyze and evaluate the efficacy of RCE for the diagnosis of AL. The data were compared by U test or χ² test between groups. Results: The incidence rate of AL after three-incision esophagectomy was 7.34% (75/1 022), including 30 cases in the RCE group and 45 cases in the non-RCE group (9.0%(30/333) vs. 6.5%(45/689), χ²=2.027, P=0.155). The diagnostic time of AL was 9(5) days postoperative (range: 4 to 30 days). Among them, 23 cases showed cervical leakages, 50 cases showed intro-thoracic leakages, and 2 cases both cervical and intro-thoracic leakages. The diagnostic time of patients with intro-thoracic leakages was longer than that of cervical leakages (10(4) days vs. 6(3) days, Z=-2.517, P=0.012). Among the 333 patients in the RCE group, 16 cases of RCE indicated leakages including 11 cases of true positive and 5 cases determined to be false positive, while 317 cases indicated no abnormalities including 19 cases developed leakages. The sensitivity and specificity of RCE to detect AL were 36.7%(11/30) and 98.3%(298/333), respectively. The Youden-index was 0.35, and the diagnostic accuracy was 92.8%(309/333). The positive and negative predictive value were 11/16 and 94.0%(298/317), respectively. Conclusions: Routine contrast esophagram after three-incision esophagectomy with cervical anastomosis has low sensitivity and high specificity in the diagnosis of AL. The diagnostic time of AL is the 9th day after surgery. It is necessary to prolong the observation time clinically, and combine RCE with CT, endoscopy and other inspection methods for diagnosis.
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Affiliation(s)
- X F Duan
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - L H He
- Department of Cardiothoracic Surgery, the First People's Hospital of Wanzhou District, Chongqing 404100, China
| | - X B Shang
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - J Yue
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - Z Ma
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - C G Chen
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - C Zhang
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - D W Qu
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - H J Jiang
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
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Huang ZF, Hu XX, Lu GS, Huang JY, Tan X, Ye Y, He LH, Huang GT. Synthesis and Characterization of Citrusinol Acetyl Derivative, and Its Interactions with DNA and BSA: 13C NMR, 1H NMR, HMBC, Fluorescence, UV–Vis spectrum, and Molecular Docking. Russ J Phys Chem 2021. [DOI: 10.1134/s0036024421070128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Dong YD, He LH, Zhang ZB. [Research progress on pain-related biomarkers of work-related musculoskeletal disorders]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2020; 38:70-73. [PMID: 32062904 DOI: 10.3760/cma.j.issn.1001-9391.2020.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Yan Y, Xia HZ, Li XS, He W, Zhu XH, Zhang ZY, Xiao CL, Liu YQ, Huang H, He LH, Lu J. [Application of U-shaped convolutional neural network in auto segmentation and reconstruction of 3D prostate model in laparoscopic prostatectomy navigation]. Beijing Da Xue Xue Bao Yi Xue Ban 2019; 51:596-601. [PMID: 31209437 DOI: 10.19723/j.issn.1671-167x.2019.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the efficacy of intraoperative cognitive navigation on laparoscopic radical prostatectomy using 3D prostatic models created by U-shaped convolutional neural network (U-net) and reconstructed through Medical Image Interaction Tool Kit (MITK) platform. METHODS A total of 5 000 pieces of prostate cancer magnetic resonance (MR) imaging discovery sets with manual annotations were used to train a modified U-net, and a set of clinically demand-oriented, stable and efficient full convolutional neural network algorithm was constructed. The MR images were cropped and segmented automatically by using modified U-net, and the segmentation data were automatically reconstructed using MITK platform according to our own protocols. The modeling data were output as STL format, and the prostate models were simultaneously displayed on an android tablet during the operation to help achieving cognitive navigation. RESULTS Based on original U-net architecture, we established a modified U-net from a 201-case MR imaging training set. The network performance was tested and compared with human segmentations and other segmentation networks by using one certain testing data set. Auto segmentation of multi-structures (such as prostate, prostate tumors, seminal vesicles, rectus, neurovascular bundles and dorsal venous complex) were successfully achieved. Secondary automatic 3D reconstruction had been carried out through MITK platform. During the surgery, 3D models of prostatic area were simultaneously displayed on an android tablet, and the cognitive navigation was successfully achieved. Intra-operation organ visualization demonstrated the structural relationships among the key structures in great detail and the degree of tumor invasion was visualized directly. CONCLUSION The modified U-net was able to achieve automatic segmentations of important structures of prostate area. Secondary 3D model reconstruction and demonstration could provide intraoperative visualization of vital structures of prostate area, which could help achieve cognitive fusion navigation for surgeons. The application of these techniques could finally reduce positive surgical margin rates, and may improve the efficacy and oncological outcomes of laparoscopic prostatectomy.
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Affiliation(s)
- Y Yan
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - H Z Xia
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - X S Li
- Institute of Electronic and Information, Tongji University, Shanghai 400047, China
| | - W He
- Department of Radiology, Peking University Third Hospital, Beijing 100191, China
| | - X H Zhu
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - Z Y Zhang
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - C L Xiao
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - Y Q Liu
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - H Huang
- School of Computer Science and Technology, Beijing Institute of Technology, Beijing 100081, China
| | - L H He
- Institute of Electronic and Information, Tongji University, Shanghai 400047, China
| | - J Lu
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
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Qian WX, Ni Y, He LH. Photoswitchable chevron topographies of glassy nematic coatings. Phys Rev E 2019; 99:052702. [PMID: 31212468 DOI: 10.1103/physreve.99.052702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Indexed: 06/09/2023]
Abstract
We report a strategy to create photoswitchable chevron topographies via buckling of glassy nematic coatings with zigzag director alignments on soft elastic substrates. The idea is confirmed by numerical simulations where the nonlinear deformation of the coating is modeled by the Föppl-von Kármán plate theory. It is remarkable that the inclination angle of the chevron pattern may deviate significantly from the director orientation and depends on the period of director alignment. Our quantitative analysis shows that the phenomena are caused by in-plane shear stress which alters the direction of maximum principal stress in the coating and decreases monotonically with decreasing period of the director distribution.
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Affiliation(s)
- W X Qian
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, China
| | - Y Ni
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, China
| | - L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, China
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Abstract
Objective: To investigate the clinical characteristics, therapy modality and prognosis of primary breast diffuse large B-cell lymphoma(PB-DLBCL). Methods: A total of 68 patients with PB-DLBCL treated in Tianjin Medical University Cancer Institute and Hospital were enrolled between January 1, 2004 and January 31, 2017. Clinicopathological data were retrospectively analyzed. 67 patients were female and only one male. The median age was 56 years old. 46 patients had Ann Arbor clinical stageⅠ~Ⅱ disease, and the other 22 were stage Ⅲ~Ⅳ. The patients with and without B symptom were 11 and 57, respectively. Kaplan-Meier method was used for univariate analysis to calculate the 5-year overall survival (OS) rate and 5-year progress-free survival (PFS) rate, compared using the log rank test. Cox regression analysis was used for multivariate analysis. Results: The 1, 3, 5-year OS rate were 84.0%, 78.0% and 73.0%, and 1, 3, 5-year PFS rate were 80.0%, 71.0% and 51.0%, respectively. Univariate analysis indicated that eastern cooperative oncology group (ECOG) score, Ann Arbor clinical stage, international prognostic index (IPI) score, risk stratification, B symptom, β2-microglobulin(β2-MG) level, size of the tumor and cycles of chemotherapy were prognostic factors for OS (all P<0.05), and Ann Arbor clinical stage, IPI score, risk stratification and B symptom were prognostic factors for PFS (all P<0.05). Multivariate analysis indicated that Ann Arbor clinical stage was independent prognostic factor for OS(P=0.029) and B symptom was independent prognostic factor for PFS(P=0.028). Conclusions: Prognosis of PB-DLBCL was relatively good. Ann Arbor clinical stage and B symptom were independent prognostic factors for OS and PFS, respectively.
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Affiliation(s)
- Y H Zhu
- Department of Breast Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
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Gao YJ, Wei YX, Chen Q, Gao M, Luo DM, Chen Y, Wang Y, Zhao Q, Yu CQ, He LH, Xu Y. [Analysis of characteristics and influencing factors of fine particulate matters and submicron particulate matters in printing shop]. Zhonghua Yu Fang Yi Xue Za Zhi 2019; 53:284-288. [PMID: 30841668 DOI: 10.3760/cma.j.issn.0253-9624.2019.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To analyze the physical characteristics of fine particulate matters (PM(2.5)) and submicron particulate matters (PM(1)), and investigate the factors influencing the emission peak of printer particles. Methods: A 12-hour particle concentration monitoring for PM(2.5) and PM(1) was conducted in a printing shop on January 5(th), 2018. PM(2.5) in the air was analyzed after the monitoring process to figure out morphological characteristics and element composition of printer particles. Besides, experiments were carried out in an enclosed space to detect the number concentration peaks of PM(1) during every printing process. Influencing factors investigated in this study were printer types, toner coverages and interval time between different printing processes. Results: The 12-hour particles concentration monitoring showed that the number concentration of PM(1) and the mass concentration of PM(2.5) were 7.510×10(4) pt/cm(3) and 96.85 μg/m(3). The diameter of most PM(2.5) was less than 100 nm, with a fractal dimension of 2.591. Most PM(2.5) appeared as regular spheres with typical agglomeration phenomenon, while some were in rhabditiform or irregular shapes. Element analysis showed that PM(2.5) was mainly composed of C, O, Si, Ca, with less metallic element. The PM(1) emission peak values of three printers were 3.60×10(4), 3.43×10(4), 0.31×10(4) pt/cm(3), respectively and the difference was not statistically significant (χ(2)=5.42, P>0.05). When the page coverage rate was 0%, 2.5%, 5%, 10%, 20% and 50%, the PM(1) emission peak value of printer A was 6.74×10(4), 4.62×10(4), 3.82×10(4), 2.82×10(4), 1.00×10(4) and 1.08×10(4) pt/cm(3), and the difference was also not statistically significant (χ(2)=7.01, P>0.05). The natural logarithm of PM(1) emission peak value in printing work was associated with the resting time before printing and the change value of heating roller temperature (r value was 0.83 and 0.89, respectively, all P values<0.05). Conclusion: PM(2.5) and PM(1) in the printing shop stayed at a high level. Particles appeared as various shapes and element compositions were complex. The temperature change of heating roller was one of most important factors that lead to the increased number concentration peak of PM(1).
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Affiliation(s)
- Y J Gao
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Y X Wei
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Q Chen
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - M Gao
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - D M Luo
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Y Chen
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Y Wang
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Q Zhao
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - C Q Yu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, China
| | - L H He
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China
| | - Y Xu
- Department of Respiratory Medicine, Peking University Renming Hospital, Beijing 100191, China
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Qin DL, Jin XN, Wang SJ, Wang JJ, Mamat N, Wang FJ, Wang Y, Shen ZA, Sheng LG, Forsman M, Yang LY, Wang S, Zhang ZB, He LH. [Research on the reliability and validity of postural workload assessment method and the relation to work-related musculoskeletal disorders of workers]. Beijing Da Xue Xue Bao Yi Xue Ban 2018; 50:488-494. [PMID: 29930418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To form a new assessment method to evaluate postural workload comprehensively analyzing the dynamic and static postural workload for workers during their work process to analyze the reliability and validity, and to study the relation between workers' postural workload and work-related musculoskeletal disorders (WMSDs). METHODS In the study, 844 workers from electronic and railway vehicle manufacturing factories were selected as subjects investigated by using the China Musculoskeletal Questionnaire (CMQ) to form the postural workload comprehensive assessment method. The Cronbach's α, cluster analysis and factor analysis were used to assess the reliability and validity of the new assessment method. Non-conditional Logistic regression was used to analyze the relation between workers' postural workload and WMSDs. RESULTS Reliability of the assessment method for postural workload: internal consistency analysis results showed that Cronbach's α was 0.934 and the results of split-half reliability indicated that Spearman-Brown coefficient was 0.881 and the correlation coefficient between the first part and the second was 0.787. Validity of the assessment method for postural workload: the results of cluster analysis indicated that square Euclidean distance between dynamic and static postural workload assessment in the same part or work posture was the shortest. The results of factor analysis showed that 2 components were extracted and the cumulative percentage of variance achieved 65.604%. The postural workload score of the different occupational workers showed significant difference (P<0.05) by covariance analysis. The results of nonconditional Logistic regression indicated that alcohol intake (OR=2.141, 95%CI 1.337-3.428) and obesity (OR=3.408, 95%CI 1.629-7.130) were risk factors for WMSDs. The risk for WMSDs would rise as workers' postural workload rose (OR=1.035, 95%CI 1.022-1.048). There was significant different risk for WMSDs in the different groups of workers distinguished by work type, gender and age. Female workers exhibited a higher prevalence for WMSDs (OR=2.626, 95%CI 1.414-4.879) and workers between 30-40 years of age (OR=1.909, 95%CI 1.237-2.946) as compared with those under 30. CONCLUSION This method for comprehensively assessing postural workload is reliable and effective when used in assembling workers, and there is certain relation between the postural workload and WMSDs.
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Affiliation(s)
- D L Qin
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - X N Jin
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - S J Wang
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - J J Wang
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - N Mamat
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - F J Wang
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - Y Wang
- CRRC Changchun Railway Vehicles CO., LTD., Changchun 130062, China
| | - Z A Shen
- CRRC Changchun Railway Vehicles CO., LTD., Changchun 130062, China
| | - L G Sheng
- CRRC Changchun Railway Vehicles CO., LTD., Changchun 130062, China
| | - M Forsman
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm SE17177, Sweden
| | - L Y Yang
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm SE17177, Sweden
| | - S Wang
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
| | - Z B Zhang
- China Academy of Safety Science and Technology, Beijing 100029, China
| | - L H He
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China
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You YH, He LH, Peng XH, Sun L, Zhang JZ. [Genomic diversity and population structure of Helicobacter pylori isolates in China]. Zhonghua Liu Xing Bing Xue Za Zhi 2017; 37:1397-1403. [PMID: 27765133 DOI: 10.3760/cma.j.issn.0254-6450.2016.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To learn about the overall genomic characteristics and population structure of Helicobacter pylori isolated in China. Methods: In this study, we used 10 public available genome sequences of H. pylori strains isolated in China, combined with other H. pylori sequences from GenBank, to analyzed the overall genomic characteristics of H. pylori isolated in China. Core genes and strain specific genes were determined for a further function definition. Results: A total of 1 203 core genes were found among all sequenced China H. pylori isolates. The number of strain specific genes ranged from 19 to 32. These genes mainly encodes hypothetical proteins which might play an important role in adaption to different hosts. Genomic variation regions were mainly in genes encoding type four secretion systems and restriction modification systems. All the China isolates belong to hpEastAsia group, hspEAsia subgroup. Prophages sequences were found in three China H. pylori strains, carrying key elements required for phage assembly. Conclusion: China H. pylori isolates belong to hpEastAsia group, hspEAsia subgroup, and some isolates contain prophages.
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Affiliation(s)
- Y H You
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
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Hu XY, Zheng XY, Ma FR, Long M, Han R, Zhou LJ, Wang F, Gong R, Pan T, Zhang SX, Du B, Jin P, Guo CY, Zheng YQ, Liu M, He LH, Qiu JH, Xu M, Song L, Xu XH, Liu XW, Wang SP. [Prevalence of hearing disorders in China: a population-based survey in four provinces of China]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2017; 51:819-825. [PMID: 27938607 DOI: 10.3760/cma.j.issn.1673-0860.2016.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the prevalence, severity of hearing disorders and demographics of people with hearing disorders based on the whole population in Jilin, Guangdong, Shannxi and Gansu provinces in China. Methods: According to " WHO Ear and Hearing Disorders Survey Protocol" , 144 clusters were chosen with probability proportional sampling(PPS) method from the four provinces covering 194, 688, 061 residents. Audiological test, otological examination and questionnaire surveying were conducted for all samples from August, 2014 to September, 2015. The hearing disorders were classified according to WHO criteria and classification. Results: Among 47 511 targeted residents, 45, 052 individuals (94.82% response rate) participated in the survey. The standardized prevalence rates of hearing disorders and disabling hearing disorders were 15.84 % and 5.17 % respectively. Almost 50% of people with hearing disorders had no awareness of it or its starting time. There was significant difference in the prevalence among people of different ages, genders, occupations, provinces, marital status and education levels. The prevalence of hearing disorders increased significantly as age grew. People above 60 years old occupied 55.31% of the total hearing disorders. The prevalence of hearing disorders among male, people of low education and those who lost husband or wife, as well as workers and farmers was relatively higher. Conclusions: The prevalence of hearing disorders is high, and hearing disorders are " invisible" . Demographics and socioeconomic factors significantly influence the prevalence of hearing disorders.
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Affiliation(s)
- X Y Hu
- China Rehabilitation Research Center for Deaf Children, Beijing 100029, China
| | - X Y Zheng
- Institute of Population Research, Peking University, Beijing 100871, China
| | - F R Ma
- Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100191, China
| | - M Long
- China Rehabilitation Research Center for Deaf Children, Beijing 100029, China
| | - R Han
- China Rehabilitation Research Center for Deaf Children, Beijing 100029, China
| | - L J Zhou
- China Rehabilitation Research Center for Deaf Children, Beijing 100029, China
| | - F Wang
- China Rehabilitation Research Center for Deaf Children, Beijing 100029, China
| | - R Gong
- Institute of Population Research, Peking University, Beijing 100871, China
| | - T Pan
- Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100191, China
| | - S X Zhang
- Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100191, China
| | - B Du
- Department of Otorhinolaryngology Head and Neck Surgery, the First Hospital of Jilin University, Changchun 130021, China
| | - P Jin
- Department of Otorhinolaryngology Head and Neck Surgery, the First Hospital of Jilin University, Changchun 130021, China
| | - C Y Guo
- Language and Hearing Rehabilitation Center of Jilin Province, Changchun 130052, China
| | - Y Q Zheng
- Department of Otorhinolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - M Liu
- Otorhinolaryngology Hospital of First Affiliated Hospital of Sun Yetsan University, Guangzhou 510080, China
| | - L H He
- Guangdong Rehabilitation Centre, Guangzhou 510055, China
| | - J H Qiu
- Department of Otorhinolaryngology Head and Neck Surgery, Xijing Hospital, Xi'an 710032, China
| | - M Xu
- Department of Otorhinolaryngology Head and Neck Surgery, Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an 710004, China
| | - L Song
- Language and Hearing Rehabilitation Center of Shanxi Province, Xi'an 710016, China
| | - X H Xu
- Department of Otorhinolaryngology, Lanzhou General Hospital, Lanzhou Command, Lanzhou 730050, China
| | - X W Liu
- Department of Otorhinolaryngology, Lanzhou University Second Hospital, Lanzhou 730030, China
| | - S P Wang
- Hearing and Language Rehabilitation Center of Gangsu Province, Lanzhou 730050, China
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Ma GW, Wang YY, He LH, Liang HJ, Su BD, Hu Y, Wang G. Study on non-point sources pollution loading of nitrogen and phosphorus in Ashi river basin. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1755-1315/69/1/012033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Jiang YG, He LH, Luo GT, Zhang XD. Prevalence of kidney stones and associated risk factors in the Shunyi District of Beijing, China. Hong Kong Med J 2017; 23:462-9. [PMID: 28416732 DOI: 10.12809/hkmj164904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Kidney stone formation is a multifactorial condition that involves interaction of environmental and genetic factors. Presence of kidney stones is strongly related to other diseases, which may result in a heavy economic and social burden. Clinical data on the prevalence and influencing factors in kidney stone disease in the north of China are scarce. In this study, we explored the prevalence of kidney stone and potentially associated risk factors in the Shunyi District of Beijing, China. METHODS A population-based cross-sectional study was conducted from December 2011 to November 2012 in a northern area of China. Participants were interviewed in randomly selected towns. Univariate analysis of continuous and categorical variables was first performed by calculation of Spearman's correlation coefficient and Pearson Chi squared value, respectively. Variables with statistical significance were further analysed by multivariate logistic regression to explore the potential influencing factors. RESULTS A total of 3350 participants (1091 males and 2259 females) completed the survey and the response rate was 99.67%. Among the participants, 3.61% were diagnosed with kidney stone. Univariate analysis showed that significant differences were evident in 31 variables. Blood and urine tests were performed in 100 randomly selected patients with kidney stone and 100 healthy controls. Serum creatinine, calcium, and uric acid were significantly different between the patients with kidney stone and healthy controls. Multivariate logistic regression revealed that being male (odds ratio=102.681; 95% confidence interval, 1.062-9925.797), daily intake of white spirits (6.331; 1.204-33.282), and a history of urolithiasis (1797.775; 24.228-133 396.982) were factors potentially associated with kidney stone prevalence. CONCLUSIONS Male gender, drinking white spirits, and a history of urolithiasis are potentially associated with kidney stone formation.
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Affiliation(s)
- Y G Jiang
- Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China
| | - L H He
- Department of Occupational & Environmental Health Sciences, School of Public Health Peking University, Beijing 100191, China
| | - G T Luo
- Department of Urology, Beijing Shun-Yi Hospital, Beijing 101300, China
| | - X D Zhang
- Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China
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14
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Jiao J, Gu GZ, Chen GS, Li YH, Zhang HL, Yang QY, Xu XR, Zhou WH, Wu H, He LH, Zheng YX, Yu SF. [Investigation into the relationship between mitochondrial 12 S rRNA gene, tRNA gene and cytochrome oxidase Ⅱ gene variations and the risk of noise-induced hearing loss]. Zhonghua Yu Fang Yi Xue Za Zhi 2017; 51:34-40. [PMID: 28056268 DOI: 10.3760/cma.j.issn.0253-9624.2017.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To explore the relationship between mitochondrial 12 S rRNA gene variation, tRNA gene variation and cytochrome oxidase Ⅱ gene point mutations and the risk of noise-induced hearing loss (NIHL). Methods: A nested case-control study was performed that followed a cohort of 7 445 noise-exposed workers in a steel factory in Henan province, China, from January 1, 2006 to December 31, 2015. Subjects whose average hearing threshold was more than 40 dB(A) in high frequency were defined as the case group, and subjects whose average hearing threshold was less than 35 dB(A) in high frequency and less than 25 dB (A) in speech frequency were defined as the control group. Subjects was recruited into the case group (n=286) and the control group (n=286) according to gender, age, job category and time of exposure to noise, and a 1∶1 case-control study was carried out. We genotyped eight single nucleotide polymorphisms in the mitochondrial 12 S rRNA gene, the mitochondrial tRNA gene and the mitochondrial cytochrome oxidase Ⅱ gene using SNPscan high-throughput genotyping technology from the recruited subjects. The relationship between polymorphic sites and NIHL, adjusted for covariates, was analyzed using conditional logistic regression analysis, as were the subgroup data. Results: The average age of the recruited subjects was (40.3±8.1) years and the length of service exposure to noise was (18.6±8.9) years. The range of noise exposed levels and cumulative noise exposure (CNE) was 80.1- 93.4 dB (A) and 86.8- 107.9 dB (A) · year, respectively. For workers exposed to noise at a CNE level<98 dB (A) · year, smokers showed an increased risk of NIHL of 1.88 (1.16-3.05) compared with non-smokers; for workers exposed to noise at a CNE level ≥98 dB(A) · year, smokers showed an increased risk of NIHL of 2.53 (1.49- 4.30) compared with non-smokers. For workers exposed to noise at a CNE level<98 dB (A) · year, the results of univariate analysis and multifactor analysis, adjusted by smoking and CNE, suggested that the risk of NIHL in workers exposed to noise carrying the GG genotype (G827A) was lower than that of NIHL workers exposed to noise carrying the AA genotype (G827A) [OR (95% CI) were 0.18 (0.04- 0.82) and 0.19 (0.04- 0.88), respectively]. Conclusion: Smoking increased the risk of NIHL in the present study. For workers subjected to a CNE<98 dB(A)·year, the mitochondrial genetic variant G827A was found to be significantly associated with the risk of NIHL.
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Affiliation(s)
- J Jiao
- Department of Occupational Health, Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
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15
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Liu XP, Ni Y, He LH. Size-dependent assembly of ligated gold nanocrystals in two dimensions. J Phys Condens Matter 2016; 28:445201. [PMID: 27605114 DOI: 10.1088/0953-8984/28/44/445201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Brownian dynamics (BD) simulation based on a coarse-grained model is performed to study the assembly of dodecanethiol-ligated Au nanocrystals (NCs) at a toluene-air interface. With increasing diameter from 3 nm to 9 nm, the NCs are found to form three different phases-a dispersed phase without aggregation, a mixture of dispersed NCs and rounded clusters, and a compactly packed solid phase of the fractal structure. Such size dependence of the assembled phase is attributed to the variation in the well depth [Formula: see text] of the interaction potential between NCs, and the value of [Formula: see text] for 6 nm NCs turns out to be most suitable to form monolayers with hexagonal packing. The result is of universal importance for assembling complete monolayers, because the valley of the interaction potential can be well tailored by properly choosing the NC size, ligand length and solvent.
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Affiliation(s)
- X P Liu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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16
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Yang QY, Xu XR, Jiao J, He LH, Yu SF, Gu GZ, Chen GS, Zhou WH, Wu H, Li YH. [Association between grainyhead-like 2 gene polymorphisms and noise-induced hearing loss]. Beijing Da Xue Xue Bao Yi Xue Ban 2016; 48:409-413. [PMID: 27318899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
OBJECTIVE To investigate association between genetic polymorphism in the grainyhead-like 2 gene (GRHL2) and noise-induced hearing loss (NIHL) in the Chinese population. METHODS A matched case-control association study was employed, In which, 3 790 workers exposed to continuous and steady-state occupational noise in a steel factory participated. The questionnaires were adopted to collect individual features and audiometry tests performed. In the sstudy, 286 subjects were diagnosed as cases, Which were each designated on the basis of the matched criterion, and 286 paired samples were selected finally. Noise intensity was measured according to the standards given in 'Measurement of Noise in the Workplace'(Occupational Health Standard of the People's Republic of China, GBZ/T189.8-2007). Cumulative noise exposure (CNE) was calculated, according to monitoring data on A-weighed sound pressure level and employment time. Genomic DNA was obtained from peripheral blood samples using 2 mL DNA extraction Kit following the manufacturer's protocol. Five single nucleotide polymorphisms (SNPs) of GRHL2 were genotyped by multiplex SNP genotyping kit. The continuous variables and categorical variables were analyzed by t-test and chi-square test respectively. Multivariate Logistic regression was used to test the association between genetic frequency and disease status, with adjustments for the possible confounding variables. The haplotypes were established and their frequencies in the two groups were assessed by haploview and phase softwares. RESULTS All the five SNPs (rs3735713, rs3824090, rs3735714, rs3735715 and rs611419) were in Hardy-Weinberg equilibrium (HWE) (P>0.05). The subjects carrying rs3735715 GG genotype had a higher NIHL risk than those carrying the GA genotype under the co-dominant model (OR=0.644, 95% CI: 0.442-0.939, P=0.022) after adjustment for height, blood pressure, drinking status and smoking status. After being stratified by CNE, in the CNE ≥ 98 dB (A) group, rs3735715 polymorphism was associated with the NIHL under the co-dominant model (OR=0.509, 95% CI: 0.281-0.923, P=0.026) after adjustment for height, blood pressure, drinking status and smoking status as well. However, no statistical significant difference was found in variant genotypes of the other SNPs between the case and control subjects. Four-locus (rs3735713, rs3824090, rs3735714 and rs3735715) haplotypes were constructed, and no risk or protective haplotypes was identified. CONCLUSION It is suggested that GRHL2 polymorphisms may be associated with development of NIHL.
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Affiliation(s)
- Q Y Yang
- Department of Occupational and Environment, Peking University School of Public Health, Beijing 100191, China
| | - X R Xu
- Department of Occupational and Environment, Peking University School of Public Health, Beijing 100191, China
| | - J Jiao
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
| | - L H He
- Department of Occupational and Environment, Peking University School of Public Health, Beijing 100191, China
| | - S F Yu
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
| | - G Z Gu
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
| | - G S Chen
- Henan Provincial Wugang Institute for Occupational Health, Wugang 462500, Henan, China
| | - W H Zhou
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
| | - H Wu
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
| | - Y H Li
- Henan Provincial Institute for Occupational Health, Zhengzhou 450052, China
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17
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Xu XR, Wang S, He LH. [The evolution of physical agents standards based on hygienic standards for the design of industrial enterprises]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2016; 34:315-8. [PMID: 27514275 DOI: 10.3760/cma.j.issn.1001-9391.2016.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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18
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Liu XP, Ni Y, He LH. Elastic properties of gold supracrystals: Effects of nanocrystal size, ligand length, and nanocrystallinity. J Chem Phys 2016; 144:144507. [PMID: 27083738 DOI: 10.1063/1.4946029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atomistic molecular dynamics simulations are performed to study the elastic properties of alkylthiol-functionalized gold supracrystals. The predicted Young's and shear moduli are around 1 GPa and 100 MPa, respectively. We show that, with increasing NC size, the Young's modulus decreases while the shear modulus essentially remains invariant; with increasing ligand length, the Young's modulus increases but the shear modulus decreases. Moreover, significant increase in the Young's modulus is seen when the polycrystalline NCs are replaced by single-crystal ones of the same size. All these are in reasonable agreement with available experiments. We attribute the mechanisms to the interaction between capping ligands as well as its variations caused by the change in ligand length and NC geometry. The results may deepen our understanding of elastic properties of the supracrystals and their influential factors.
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Affiliation(s)
- X P Liu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Y Ni
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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19
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Abstract
Interparticle spacing in supracrystals is a crucial parameter for photoelectric applications as it dominates the transport rates between neighboring nanoparticles (NPs). Based on large-scale molecular dynamics simulations, we calculate interparticle spacing in alkylthiol-stabilized gold supracrystals as a function of the NP size, ligand length and external pressure. The repulsive many-body interactions in the supracrystals are also quantified by comparing the interparticle spacing with that between two individual NPs at equilibrium. Our results are consistent with available experiments, and are expected to help precise control of interparticle spacing in supracrystal devices.
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Affiliation(s)
- X P Liu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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20
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Song ZQ, Ni Y, Peng LM, Liang HY, He LH. Interface failure modes explain non-monotonic size-dependent mechanical properties in bioinspired nanolaminates. Sci Rep 2016; 6:23724. [PMID: 27029955 PMCID: PMC4814825 DOI: 10.1038/srep23724] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/08/2016] [Indexed: 11/25/2022] Open
Abstract
Bioinspired discontinuous nanolaminate design becomes an efficient way to mitigate the strength-ductility tradeoff in brittle materials via arresting the crack at the interface followed by controllable interface failure. The analytical solution and numerical simulation based on the nonlinear shear-lag model indicates that propagation of the interface failure can be unstable or stable when the interfacial shear stress between laminae is uniform or highly localized, respectively. A dimensionless key parameter defined by the ratio of two characteristic lengths governs the transition between the two interface-failure modes, which can explain the non-monotonic size-dependent mechanical properties observed in various laminate composites.
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Affiliation(s)
- Z. Q. Song
- CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Y. Ni
- CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - L. M. Peng
- CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - H. Y. Liang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - L. H. He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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21
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Abstract
Ankylosed bone mass in temporomandibular joint ankylosis (TMJA) is an important factor affecting mouth-opening limitation. However, the mechanism underlying the occurrence of ankylosed bone mass remains unknown. Research has shown that osteoblasts and osteoclasts maintain balance in bone remodeling. Thus, we hypothesized that aberrant osteoclastogenesis and osteogenesis may be involved in the occurrence of ankylosed bone mass in TMJA. In this study, we characterized the osteogenesis of bone marrow stem cells and the osteoclastogenesis of myelomonocyte in clinical specimens of TMJA and normal controls. Results showed that, compared with control bone marrow stem cells, TMJA bone marrow stem cells had lower proliferative and osteogenic capacities. The number of osteoclasts in the ankylosed bone mass group dramatically decreased, and myelomonocyte osteoclastogenic potential was impaired. The RANKL/OPG ratio of the ankylosed bone mass group was lower than that of the control group. Thus, our study suggests that osteoclast deficiency may be an important factor affecting bone mass ankylosis.
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Affiliation(s)
- L H He
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Haidian District, Beijing, China
| | - E Xiao
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Haidian District, Beijing, China
| | - D H Duan
- Department of General Dentistry, Peking University School and Hospital of Stomatology, Haidian District, Beijing, China
| | - Y H Gan
- Central Laboratory and Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Haidian District, Beijing, China
| | - Y Zhang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Haidian District, Beijing, China
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22
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Abstract
We performed a coarse-grained. molecular dynamics (MD) simulation to study the unidirectional tension of 2D superlattices of alkythiol-ligated Au nanocrystals (NCs). Consistent with available experiments, the predicted Young's modulus is in the range of 6-15 GPa, exhibiting a trend of decreasing with the increasing NCs' size and decreasing ligand length. Our simulation shows that the deformation of the superlattice experiences elastic and nonelastic stages before defect nucleation at the NC level. The larger tensile strain gives rise to slips along the most densely packed lines, making them equal to [Formula: see text] with the tensile direction before deformation, which further triggers the occurrence of cavities and cracks and finally leads to the fracture of the specimen. These results provide a clear picture for the tensile behavior of 2D superlattices from deformation to rupture.
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Affiliation(s)
- X P Liu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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23
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He LH. Thickness-dependent attraction or repulsion between defects on a thin elastic film. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 89:062409. [PMID: 25019796 DOI: 10.1103/physreve.89.062409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Indexed: 06/03/2023]
Abstract
We examine elastic interaction between two defects on one side or two sides of an isotropic thin film. We show that the tangential and normal forces contribute to the interaction in a coupled manner. Our finding is that the attraction or repulsion between two defects exhibiting twofold symmetry is dependent on the film thickness. The result is of particular importance for probing elastic interaction between adherent cells which have been commonly treated as twofold surface defects.
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Affiliation(s)
- L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials & Institute of Solid State Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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24
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He LH. Response of constrained glassy splay-bend and twist nematic sheets to light and heat. Eur Phys J E Soft Matter 2013; 36:83. [PMID: 23921449 DOI: 10.1140/epje/i2013-13083-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 06/09/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
A general approach is proposed to analyze the complex photo- or thermo-response of glassy splay-bend and twist nematic sheets with boundary constraints. The governing equations are two-dimensional, as in the classical plate theory. However, the solution can generate exact three-dimensional displacement and stress distributions within the interior of the sheets, except the boundary layer whose width is of the same order of the sheet thickness.
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Affiliation(s)
- L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, 230026 Hefei, Anhui, P.R. China.
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25
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Abstract
The ultra-sensitivity of mass detectors using individual cantilevered single-walled carbon nanocone (SWCNC) resonators is first investigated. A higher-order gradient theory, derived at the atomic level, is applied for modeling SWCNC resonators. Numerical simulations using a mesh-free computational framework based on moving Kriging interpolation are conducted to investigate the mass sensitivity of cantilevered SWCNC resonators with extra mass loading as well as with equivalent single-walled carbon nanotube (SWCNT) resonators. Comparison of the magnitude of resonant frequency shifts, the key criterion for mass sensitivity, of these two kinds of resonators demonstrates a far higher mass sensitivity for SWCNC resonators than for SWCNT resonators, thus suggesting a new method for ultra-sensitive mass detection via SWCNC resonators. The dependence of the mass sensitivity of SWCNC resonators on height and top radii has been examined. A reduction in the height of SWCNC resonators gives rise to a considerable increase in mass sensitivity. The mass sensitivity of a 6 nm high SWCNC resonator can even reach a level of 10(-22) g. It is noteworthy that the top radii of SWCNC resonators have a slight effect on frequency shifts. Another interesting observed phenomenon is that a deviation in the height of 19.2° SWCNC resonators leads to little loss in precision of mass detection when the attached mass is smaller than 10(-20) g. This superior characteristic indicates that SWCNC-based mass detectors have great potential in practical applications.
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Affiliation(s)
- J W Yan
- Department of Civil and Architectural Engineering, City University of Hong Kong, Kowloon, Hong Kong
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26
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Abstract
Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011.
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Affiliation(s)
- A Lee
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
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27
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Qiao L, He LH. Anisotropic dewetting on stretched elastomeric substrates. Eur Phys J E Soft Matter 2008; 26:387-393. [PMID: 19230211 DOI: 10.1140/epje/i2008-10334-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We study the instability of a very thin liquid film resting on a uniformly stretched soft elastomeric substrate driven by van der Waals forces. A linear stability analysis shows that the critical fluctuation wavelength in the tensile direction is larger than those in the other directions. The magnitudes of the critical wavelengths are adjustable in the sense that they depend on the principal stretch of the substrate. For example, when the principal stretch of the substrate varies from 1.0 (unstretched) to 3.0, the range of the critical wavelength in the tensile direction increases by 7.0% while that normal to the tensile direction decreases by 8.7%. Therefore, the phenomenon may find potential applications in creating tunable topographically patterned surfaces with nano- to microscale features.
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Affiliation(s)
- L Qiao
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, PRC
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28
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He LH. Surface deformation of nematic elastomers under striped illumination. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 75:041702. [PMID: 17500908 DOI: 10.1103/physreve.75.041702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Indexed: 05/15/2023]
Abstract
Nematic elastomers containing azobenzene chromophores are activated upon photoabsorption. We study the surface deformation of such elastomers under striped illumination. For an arbitrary orientation of the nematic axis, we obtain an analytical solution to the problem via a phenomenological continuum model. Numerical computations indicate that the profile of the deformed surface depends not only on the stripe width but also on the orientation of the nematic axis. The result may provide a mechanism to manipulate the surface topography of elastomers.
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Affiliation(s)
- L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, China.
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29
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Abstract
Due to the disruption of liquid-crystal order caused by photoisomerization of the rodlike molecules, solids containing light-sensitive molecules such as nematic liquid-crystal elastomers can undergo large reversible shape changes when stimulated by light. In this paper, we study surface deformation of such solids illuminated by light based on a phenomenological model. Numerical computation shows that the deformation topography of the surface depends remarkably on the spot radius of light. The result is expected helpful to practical applications related to the creation of surface patterns, such as guidance of microfluids and manipulation of nanostructures.
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Affiliation(s)
- Z Y Wei
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
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30
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Lim CW, Wu BS, He LH. A new approximate analytical approach for dispersion relation of the nonlinear Klein-Gordon equation. Chaos 2001; 11:843-848. [PMID: 12779523 DOI: 10.1063/1.1423335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A novel approach is presented for obtaining approximate analytical expressions for the dispersion relation of periodic wavetrains in the nonlinear Klein-Gordon equation with even potential function. By coupling linearization of the governing equation with the method of harmonic balance, we establish two general analytical approximate formulas for the dispersion relation, which depends on the amplitude of the periodic wavetrain. These formulas are valid for small as well as large amplitude of the wavetrain. They are also applicable to the large amplitude regime, which the conventional perturbation method fails to provide any solution, of the nonlinear system under study. Three examples are demonstrated to illustrate the excellent approximate solutions of the proposed formulas with respect to the exact solutions of the dispersion relation. (c) 2001 American Institute of Physics.
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Affiliation(s)
- C. W. Lim
- Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
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31
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Xing TX, He DY, He LH, Zhou WJ, Liao XL, Chen HP. Fate and metabolism of nitrogen in goats fed 15N-labelled rice straw. Asian Australas J Anim Sci 1992. [DOI: 10.5713/ajas.1992.699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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32
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Wang ET, Zhou DR, He LH. Histaminergic response to Coriolis stimulation: implication for transdermal scopolamine therapy of motion sickness. Aviat Space Environ Med 1992; 63:579-82. [PMID: 1616432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The blood levels of histamine and 5-hydroxytryptamine (5-HT) in 10 subjects, with or without administration of the transdermal therapeutic system of scopolamine (TTS-S), were measured following motion sickness (MS) induced by Coriolis stimulation. Histamine and 5-HT were assayed using the fluorometric method. The results demonstrated that the blood levels of histamine increased significantly following MS and were even higher in the subjects using TTS-S, but we found neither significant changes in the blood levels of 5-HT following MS nor any effect of TTS-S on it. The results suggest that histamine contributes to the development of MS, and scopolamine may exert its anti-MS action by affecting the histaminergic system as well as the acetylcholinergic system; there may not be a definite relation between 5-HT and the development of MS.
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Affiliation(s)
- E T Wang
- Department of Otolaryngology, General Hospital of Air Force, Beijing, P.R. China
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