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Vertical holding capacity of torpedo anchors in underwater cohesive soils

OCEAN ENGINEERING 2018年 161卷 291-307页

作者： Wang, Wenkai Wang, Xuefeng Yu, Guoliang Shanghai Jiao Tong Univ Sch Naval Architecture Ocean & Civil Engn SKLOE CISSE Shanghai 200240 Peoples R China China Waterbome Transport Res Inst Beijing 100088 Peoples R China

Torpedo anchors are regarded as one of the most efficient mooring solutions for taut mooring systems and can withstand vertical loads. The estimation of the undrained pullout capacity of the anchors is vital for the design of offshore floating facilities. There have been some achievements obtained for the calculation of the holding capacity of a torpedo anchor via field tests, conventional model tests under one gravity, centrifuge tests with a high value of gravity acceleration and numerical tests. However, a simple and reliable formula is still required to calculate the holding capacity of a torpedo anchor. In this study, 240 sets of laboratory tests were performed, and 11 differently shaped model anchors, vertically embedded in a soft sedimentary bed, were pulled out vertically from different types of cohesive soils and different embedment depths. The characteristics of the loading curves were analyzed, and the relationship between the pullout capacities and properties of the anchors and types of soils were investigated. Based on force analysis and the laboratory data, a formula was proposed for the calculation of the undrained monotonic holding capacity of a torpedo anchor, which mainly depends on the embedded depth of the anchor, net weight, geometry, and in situ soil properties. The calculated vertical holding capacities were consistent with the laboratory and field data obtained by the authors and other scientists.

关键词： Torpedo anchor Pullout force Vertical pullout capacity Cohesive soil Embedded depth

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Structural basis for the acetylation of histone H3K9 and H3K27 mediated by the histone chaperone Vps75 in Pneumocystis carinii

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Signal Transduction and Targeted Therapy 2019年第1期4卷 550-561页

作者： Yiping Chen Yang Zhang Hui Ye Yanshu Dou Deren Lu Xiaolu Li Andrew H.Limper Junhong Han Dan Su State Key Laboratory of Biotherapy and Cancer Center West China HospitalSichuan UniversityChengduSichuanP.R.China Center of Infectious Diseases West China Hospital of Sichuan UniversityChengduSichuanP.R.China International Center for Translational Chinese Medicine Sichuan Academy of Chinese Medicine SciencesP.R.ChinaChengduSichuanP.R.China Thoracic Diseases Research Unit Mayo Clinic College of MedicineRochesterMNUSA

Rtt109 is a histone acetyltransferase(HAT)that is a potential therapeutic target in conditioned pathogenic fungi Pneumocystis carinii(***).The histone chaperone Vps75 can stimulate the Rtt109-dependent acetylation of several histone H3 lysines and preferentially acetylates H3K9 and H3K27 within canonical histone(H3–H4)2 ***75 shows two protein conformations assembled into dimeric and tetrameric forms,but the roles played by multimeric forms of Vps75 in Rtt109-mediated histone acetylation remain *** ***,we identified that Vps75(PcVps75)dimers regulate H3K9 and H3K27 acetylation by directly interacting with histone(H3–H4)2 tetramers,rather than by forming a Vps75-Rtt109 *** PcVps75 tetramers,the major histone-binding surface is buried within a walnut-like structure in the absence of a histone *** on crystal structures of dimeric and tetrameric forms of PcVps75,as well as HAT assay data,we confirmed that residues 192E,193D,194E,195E,and 196E and the disordered C-terminal tail(residues 224–250)of PcVps75 mediate interactions with histones and are important for the Rtt109 in ***(PcRtt109)-mediated acetylation of H3K9 and H3K27,both in vitro and in yeast ***,expressing PcRtt109 alone or in combination with PcVps75 variants that cannot effectively bind histones could not fully restore cellular growth in the presence of genotoxic agents that block DNA replication owing to the absence of H3K9 and H3K27 ***,these data indicate that the interaction between PcVps75 and histone(H3–H4)2 tetramers is a critical regulator of the Rtt109-mediated acetylation of H3K9 and H3K27.

关键词： residues Together acetylation

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Fast first-photon ghost imaging

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SCIENTIFIC REPORTS 2018年第1期8卷 1-8页

作者： Liu, Xialin Shi, Jianhong Wu, Xiaoyan Zeng, Guihua Shanghai Jiao Tong Univ State Key Lab Adv Opt Commun Syst & Networks Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Ctr Quantum Sensing & Informat Proc QSIP Shanghai 200240 Peoples R China

Conventional imaging at low light levels requires hundreds of detected photons per pixel to suppress the Poisson noise for accurate reflectivity inference. We propose a high-efficiency photon-limited imaging technique, called fast first-photon ghost imaging, which recovers the image by conditional averaging of the reference patterns selected by the first-photon detection signal. Our technique merges the physics of low-flux measurements with the framework of computational ghost imaging. Experimental results demonstrate that it can reconstruct an image from less than 0.1 detected photon per pixel, which is three orders of magnitude less than conventional imaging techniques. A signalto-noise ratio model of the system is established for noise analysis. With less data manipulation and shorter time requirements, our technique has potential applications in many fields, ranging from biological microscopy to remote sensing.

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Effects of Growth Stage development on Paddy Rice Leaf Area Index Prediction Models

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REMotE SENSING 2019年第3期11卷

作者： Wang, Li Chang, Qingrui Li, Fenling Yan, Lin Huang, Yong Wang, Qi Luo, Lili Northwest A&F Univ Coll Nat Resources & Environm Yangling 712100 Shaanxi Peoples R China Sun Yat Sen Univ Sch Geog & Planning Guangzhou 510275 Guangdong Peoples R China

A in situ hyperspectral dataset containing multiple growth stages over multiple growing seasons was used to build paddy rice leaf area index (LAI) estimation models with a special focus on the effects of paddy rice growth stage development. The univariate regression method applied to the vegetation index (VI), the traditional multivariate calibration method of partial least squares regression (PLSR), and modern machine learning methods such as support vector regression (SVR), random forests (RF), and artificial neural networks (ANN) based on the original and first-derivative hyperspectral data were evaluated in this study for paddy rice LAI estimation. All the models were built on the whole growing season and on each separate vegetative, reproductive and ripening growth stage of paddy rice separately. To ensure a fair comparison, the models of the whole growing season were also validated on data for each separate growth stage of the standalone validation dataset. Moreover, the optimal band pairs for calculating narrowband difference vegetative index (DVI), normalized difference vegetation index (NDVI) and simple ratio vegetation index (SR) were determined for the whole growing season and for each separate growth stage separately. The results showed that for both the whole growing season and for each single growth stage, the red-edge and near-infrared band pairs are optimal for formulating the narrowband DVI, NDVI and SR. Among the four multivariate calibration methods, SVR and RF yielded more accurate results than the other two methods. The SVR and RF models built on first-derivative spectra provided more accurate results than the corresponding models on the original spectra for both whole growing season models and separate growth stage models. Comparing the prediction accuracy based on the whole growing season revealed that the RF and SVR models showed an advantage over the VI models. However, comparing the prediction accuracy based on each growth stage separately

关键词： LAI paddy rice hyperspectral machine learning vegetation index growth stage

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Removal of Heavy Metals and Metalloids by Amino-Modified Biochar Supporting Nanoscale Zero-Valent Iron

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JOURNAL OF ENVIRONMENTAL QUALITY 2018年第5期47卷 1196-1204页

作者： Yang, Jingjing Ma, Tianxing Li, Xiaoqin Tu, Jingwei Dang, Zhi Yang, Chen South China Univ Technol Sch Environm & Energy Guangzhou 510006 Guangdong Peoples R China Minist Educ Key Lab Pollut Control & Ecosyst Restorat Ind Clu Guangzhou 510006 Guangdong Peoples R China Guangdong Prov Engn & Technol Res Ctr Environm Ri Guangzhou 510006 Guangdong Peoples R China Guangdong Environm Protect Key Lab Solid Waste Tr Guangzhou 510006 Guangdong Peoples R China

Nanoscale zero-valent iron (nZVI), an environmentally benign material, has been used to remove heavy metals and metalloids from the aqueous phase because of its high reactivity and abundant reactive sites. To improve the stability of nZVI, nanoscale zero-valent iron supported by amino-modified biochar (ZVIA-BC) was prepared and characterized. Its ability to remove heavy metals and metalloid was investigated. Fourier transform infrared spectroscopy analyses showed that the amino group was chemically bound to the functional groups of biochar. X`-ray photoelectron spectroscopy (XPS) and X`-ray diffraction revealed that zero-valent iron was loaded on the biochar surface. high-resolution transmission electron microscope images showed that the particle size of iron was similar to 50 nm and the particles consisted of roughly spherical cores covered with a shell that was uniformly 2- to 3-nm thick. Furthermore, measuring the zeta potentials at various pH values indicated that the iso-electric points occurred within the pH range of 7.50 to 7.56. Additionally, heavy metals and metalloids, including Cd(II), Ni(II), Cu(II), Cr(VI) and As(V) adsorption isotherms, on ZVIA-BC were significantly nonlinear, and ZVIA-BC exhibited a superior ability to remove these heavy metals and metalloids, especially for Cr(VI) and As(V). Characterization with high-resolution XPS revealed that reduction of heavy metals and metalloids occurred on the surface of ZVIA-BC. The main mechanisms for removal were reduction, complexation, co-precipitation, and electrostatic interaction.

关键词： Heavy metals

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Identification of LBX2 as a novel causal gene of atrial septal defect

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INTERNATIONAL JOURNAL OF CARDIOLOGY 2018年 265卷 188-194页

作者： Wang, Jing Luo, Jing Chen, Qiuhong Wang, Xi He, Jiangyan Zhang, Wei Yin, Zhan Zheng, Fang Pan, Hong Li, Tengyan Lou, Qiyong Wang, Binbin Capital Med Univ Sch Basic Med Sci Dept Med Genet & Dev Biol Beijing 100069 Peoples R China Wuhan Univ Zhongnan Hosp Ctr Gene Diag Wuhan 430071 Hubei Peoples R China Qinghai High Altitude Med Res Inst Cardiovasc Ctr Xining 810012 Peoples R China Natl Res Inst Family Planning Ctr Genet Beijing 100081 Peoples R China Chinese Acad Sci Inst Hydrobiol Key Lab Aquat Biodivers & Conservat Wuhan 430072 Hubei Peoples R China

Background: Atrial septal defect (ASD) is one of the most common cardiac malformations worldwide. Several genes have been identified so far, which can merely explain small proportion of all the cases, therefore, it is anticipated that there are additional genes causing ASD. The aims of this study were to identify the causal gene of ostium secundum atrial septal defect (ASDII) in a Chinese family. Methods: Whole exome sequencing was performed in three affected members and one control in the ASDII family. We screened mutations of LBX2 in 300 unrelated ASD patients and validated in 400 normal controls by Sanger sequencing. LBX2 knockout zebrafish was generated by CRISPR/Cas9 to detect whether lbx2 deficiency influenced cardiac development. Results: A rare missense mutation in LBX2 (c.A403G:p.K135E) was identified as the pathogenic cause of ASD. Subsequent mutation screening revealed two missense variants in 3 of 300 sporadic patients. We observed expanded size of atrium and ventricle in LBX2 knockout zebrafish through hematoxylin-eosin staining, more incompact distribution of cardiac myocytes was also discovered in homozygote compared with in wildtype. Furthermore, we performed in situ hybridization of crip2 gene to trace the cardiac neural crest cells in the embryo stage and found that the migration of neural crest cells was obviously delayed in the homozygotes. Conclusions: We identified LBX2 for the first time as a pathogenic gene of ASDII. LBX2 deficiency may cause abnormal development of heart through influencing the migration of neural crest cells and affect the process of cardiac septation. (c) 2018 Elsevier B.V. All rights reserved.

关键词： Atrial septal defect LBX2 Neural crest cells Whole exome sequencing

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Intensity-based 2D-3D registration for an ACL reconstruction navigation system

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INTERNATIONAL JOURNAL OF MEDICAL ROBotICS AND COMPUTER ASSISTED SURGERY 2019年第4期15卷 e2008页

作者： Guo, Na Yang, Biao Ji, Xuquan Wang, Yuhan Hu, Lei Wang, Tianmiao Beihang Univ Sch Mech Engn & Automat Beijing Peoples R China Beihang Univ Beijing Adv Innovat Ctr Biomed Engn Beijing Peoples R China

To improve the positioning accuracy of tunnels for anterior cruciate ligament (ACL) reconstruction, we proposed an intensity-based 2D-3D registration method for an ACL reconstruction navigation system. Methods for digitally reconstructed radiograph (DRR) generation, similarity measurement, and optimization are crucial to 2D-3D registration. We evaluated the accuracy, success rate, and processing time of different methods: (a) ray-casting and splating were compared for DRR generation;(b) normalized mutual information (NMI), Mattes mutual information (MMI), and Spearman's rank correlation coefficient (SRC) were assessed for similarity between registrations;and (c) gradient descent (GD) and downhill simplex (DS) were compared for optimization. The combination of splating, SRC, and GD provided the best composite performance and was applied in an augmented reality (AR) ACL reconstruction navigation system. The accuracy of the navigation system could fulfill the clinical needs of ACL reconstruction, with an end pose error of 2.50 mm and an angle error of 2.74 degrees.

关键词： ACL reconstruction intensity-based 2D-3D registration surgical navigation system

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Evaluation of Leaf N Concentration in Winter Wheat Based on Discrete Wavelet Transform Analysis

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REMotE SENSING 2019年第11期11卷

作者： Li, Fenling Wang, Li Liu, Jing Wang, Yuna Chang, Qingrui Northwest A&F Univ Coll Nat Resources & Environm Yangling 712100 Shaanxi Peoples R China Minist Agr Key Lab Plant Nutr & Agrienvironm Northwest China Yangling 712100 Shaanxi Peoples R China

Leaf nitrogen concentration (LNC) is an important indicator for accurate diagnosis and quantitative evaluation of plant growth status. The objective was to apply a discrete wavelet transform (DWT) analysis in winter wheat for the estimation of LNC based on visible and near-infrared (400-1350 nm) canopy reflectance spectra. In this paper, in situ LNC data and ground-based hyperspectral canopy reflectance was measured over three years at different sites during the tillering, jointing, booting and filling stages of winter wheat. The DWT analysis was conducted on canopy original spectrum, log-transformed spectrum, first derivative spectrum and continuum removal spectrum, respectively, to obtain approximation coefficients, detail coefficients and energy values to characterize canopy spectra. The quantitative relationships between LNC and characteristic parameters were investigated and compared with models established by sensitive band reflectance and typical spectral indices. The results showed combining log-transformed spectrum and a sym8 wavelet function with partial least squares regression (PLS) based on the approximation coefficients at decomposition level 4 most accurately predicted LNC. This approach could explain 11% more variability in LNC than the best spectral index mSR(705) alone, and was more stable in estimating LNC than models based on random forest regression (RF). The results indicated that narrowband reflectance spectroscopy (450-1350 nm) combined with DWT analysis and PLS regression was a promising method for rapid and nondestructive estimation of LNC for winter wheat across a range in growth stages.

关键词： leaf nitrogen concentration discrete wavelet transform partial least squares hyper-spectra

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Ultracompact Optical Hybrid Based on Standing Wave Integrated With Graphene-Based Photodetector for Coherent Detection

IEEE PHOTONICS JOURNAL

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IEEE PHotONICS JOURNAL 2018年第6期10卷

作者： Xu, Jing Zhao, Yanli Wen, Ke Tu, Junjie Huazhong Univ Sci & Technol Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China

In this paper, we propose a novel scheme to integrate an optical hybrid based on standing wave with graphene photodetector (GPD). Different from optical hybrids based on multimode interference (MMI) couplers, the proposed optical hybrid can be miniaturized by constructing a standing wave field in a silicon strip waveguide. The waveguide-integrated GPD with symmetric electrodes is adopted as an ultrafast self-differential photodetector (SDPD), instead of conventional balanced-photodetectors (BPDs) based on p-i-n photodiodes in a coherent receiver. By placing two sysmmetric interdigitated electrodes of the SDPD at nodes and antinodes of the standing wave, it is convenient to realize the integration of the proposed optical hybrid with the graphene-based SDPD, which can effectively reduce the complexity of a coherent receiver and meet the future demand for wide bandwidth. The finite-difference time-domain method was used to calculate optical absorption for demonstrating operation feasibility. Finally, device bandwidth and effective responsivity have been discussed. In theory, our scheme would provide a feasible way to realize a high-speed compact coherent receiver.

关键词： Integrated optics devices coherent detection optical hybrid graphene photodetector

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Extended Application Of Time-Varying Observer For Rigid Rotors Unbalance Estimation During Acceleration 3

Extended Application Of Time-Varying Observer For Rigid Roto...

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3rd International Conference on Mechanical, Manufacturing, Modeling and Mechatronics (IC4M) / 3rd International Conference on Design, Engineering and Science (ICDES)

作者： Yu, Xunxing Mao, Kuanmin Zhu, Yaming Huazhong Univ Sci & Technol Sch Mech Sci & Engn Wuhan 430074 Hubei Peoples R China

Unbalance is one of essential problems for modern rotating machines. In this work, an improved time-varying observer is proposed to estimate the unbalance of rigid rotor during acceleration. In order to fitting different speed acceleration laws, the unbalance forces have been included in an new designed augmented states, meanwhile the state space model of rigid rotor has been also developed. The developed state space model is transformed to a canonical transformation and a new designed time-varying observer can be obtained. The estimated unbalances can be directly obtained by using this time-varying observer. This method would be very helpful for active balancing control strategy during acceleration.

关键词： State space methods

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