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Discrimination of False Negative Results in RT-PCR Detection of SARS-CoV-2 RNAs in Clinical Specimens by Using an Internal Reference

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Virologica Sinica 2020年第6期35卷 758-767页

作者： Yafei Zhang Changtai Wang Mingfeng Han Jun ye Yong Gao Zhongping liu Tengfei He Tuantuan li Mengyuan Xu Luping Zhou Guizhou Zou Mengji Lu Zhenhua Zhang Department of Infectious Diseases The Second Hospital of Anhui Medical UniversityHefei 230601China Institute of Clinical Virology The Second Hospital of Anhui Medical UniversityHefei 230601China Department of Internal Medicine The Second Hospital of FuyangFuyang 236015China Institute for Virology University Hospital of EssenUniversity of Duisburg-Essen45147 EssenGermany

Reverse transcription-polymerase chain reaction(RT-PCR)is an essential method for specific diagnosis of SARS-CoV-2 ***,false negative test results are often *** this study,we attempted to determine the principal causes leading to false negative results of RT-PCR detection of SARS-CoV-2 RNAs in respiratory tract *** sputum and throat swab specimens from 161 confirmed COVID-19 patients were tested with a commercialfluorescent RT-PCR kit targeting the ORF1 ab and N regions of SARS-CoV-2 *** RNA level of a cellular housekeeping gene ribonuclease P/MRP subunit p30(RPP30)in these specimens was also assessed by *** for a total of 1052 samples were retrospectively re-analyzed and a strong association between positive results in SARS-CoV-2 RNA tests and high level of RPP30 RNA in respiratory tract specimens was *** using the ROC-AUC analysis,we identified Ct cutoff values for RPP30 RT-PCR which predicted false negative results for SARS-CoV-2 RT-PCR with high sensitivity(95.03%–95.26%)and specificity(83.72%–98.55%)for respective combination of specimen type and ampli-fication *** these Ct cutoff values,false negative results could be reliably ***,the presence of cellular materials,likely infected host cells,are essential for correct SARS-CoV-2 RNA detection by RT-PCR in patient ***30 could serve as an indicator for cellular content,or a surrogate indicator for specimen *** addition,our results demonstrated that false negativity accounted for a vast majority of contradicting results in SARS-CoV-2 RNA test by RT-PCR.

关键词： COVID-19 SARS-CoV-2 RT-PCR False negative results Internal reference

One-step synthesis of fluorescent hydroxyls-coated carbon dots with hydrothermal reaction and its application to optical sensing of metal ions

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Science China Chemistry 2011年第8期54卷 1342-1347页

作者： liu liQin li YuanFang ZHAN Lei liu Yue HUANG ChengZhi Education Ministry Key Laboratory on Luminescence and Real-Time Analysis College of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China CoUege of Pharmaceutical Sciences Southwest University Chongqing 400715 China

Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).

关键词： carbon dots fluorescence quantum yield cytotoxicity metal ions

Synthesis and characterization of novel redox-active percec-type dendrons

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Chinese Chemical Letters 2012年第4期23卷 438-441页

作者： Zhi Yu Cheng Bi ye Ren Rui liu Xue Yi Chang Zhen Tong Research Institute of Materials Science South China University of TechnologyGuangzhou 510640China

Three novel redox-active percec-type dendrons were synthesized by mucleophilic substitution reaction of 11-bromoundecyl ferrocene and substituted *** the resultant ferrocenyl-modified dendrons were confirmed through FT-IR,NMR,and elemental analysis,***,the thermal properties and electrochemical behavior of these dendrons were monitored with thermogravimetry analysis（TG）,differential scanning calorimetry（DSC）,polarized optical microscope（POM）,and cyclic voltammetry（CV）. Abound phase behavior and reversible electrochemical redox reaction process in the DMF solution of these dendrons was observed.

关键词： Redox-active Percec-type dendrons Ferrocenyl group Building block

Road Lateral Disconnection and Crossing Impacts in River Landscape of Lancang River Valley in Yunnan Province,China

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Chinese Geographical Science 2014年第1期24卷 28-38页

作者： WANG Cong liu Shiliang DENG li liu Qi YANG Juejie School of Environment Beijing Normal University

Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed *** this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network *** study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain *** results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the *** lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin *** erosion intensity decreased with increasing lateral road buffer *** erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion *** addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin *** factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of *** correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.

关键词： lateral disconnection crossing impacts river landscape patch density soil erosion scale effect

Agglomerated Pd Catalysts and Their Applications in Hydrogen Production from Formic Acid Decomposition at Room Temperature

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Chemical Research in Chinese Universities 2016年第2期32卷 272-277页

作者： liu Jun LAN lixin WU Chao li Rong liu Xuanyan Department of Pharmaceutical and Biological Engineering Hunan Chemical Vocational Technology College Zhuzhou 412004 P. R. China

Agglomerated Pd catalysts with the nano-porous structure were simply prepared by one-step reduction reaction without using any stabilizer. The Pd catalysts show a high catalytic activity for the decomposition of formic acid at room temperature. Among all the Pd catalysts tested, the Pdug catalyst exhibits the highest catalytic activity. Moreover, the breakthrough of the advanced catalysts is that the above agglomerated Pd catalysts can be easily separated from the liquid system to control the catalytic reaction at any time, which may further promote the practical application of formic acid as a H2 storage material.

关键词： Hydrogen energy Heterogeneous catalyst Formic acid decomposition Pd catalyst Nano-porous structure

Modified unscented Kalman filter using modified filter gain and variance scale factor for highly maneuvering target tracking

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Journal of Systems Engineering and Electronics 2014年第3期25卷 380-385页

作者： Changyun liu Penglang Shui Gang Wei Song li National Laboratory of Radar Signal Processing Xidian University College of Air and Missile Defense Air Force Engineering University

To improve the low tracking precision caused by lagged filter gain or imprecise state noise when the target highly maneuvers, a modified unscented Kalman filter algorithm based on the improved filter gain and adaptive scale factor of state noise is presented. In every filter process, the estimated scale factor is used to update the state noise covariance Qk, and the improved filter gain is obtained in the filter process of unscented Kalman filter （UKF） via predicted variance Pk｜k-1, which is similar to the standard Kalman filter. Simulation results show that the proposed algorithm provides better accuracy and ability to adapt to the highly maneuvering target compared with the standard UKF.

关键词： unscented Kalman filter (UKF) target tracking filter gain maneuvering target nonlinearity modified unscented Kalman filter (MUKF).

Pedestrian detection algorithm based on video sequences and laser point cloud

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Frontiers of Computer Science 2015年第3期9卷 402-414页

作者： Hui li Yun liu Shengwu XIONG lin WANG School of Information Science and Technology Qingdao University of Science and Technology Qingdao 266061 China School of Computer Science Wuhan University of Technology Wuhan 430070 China

Pedestrian detection is a critical problem in the field of computer vision. Although most existing algorithms are able to detect pedestrians well in controlled environ- ments, it is often difficult to achieve accurate pedestrian de- tection from video sequences alone, especially in pedestrian- intensive scenes wherein pedestrians may cause mutual oc- clusion and thus incomplete detection. To surmount these dif- ficulties, this paper presents pedestrian detection algorithm based on video sequences and laser point cloud. First, laser point cloud is interpreted and classified to separate pedes- trian data and vehicle data. Then a fusion of video image data and laser point cloud data is achieved by calibration. The re- gion of interest after fusion is determined using feature in- formation contained in video image and three-dimensional information of laser point cloud to remove false detection of pedestrian and thus to achieve pedestrian detection in inten- sive scenes. Experimental verification and analysis in video sequences demonstrate that fusion of two data improves the performance of pedestrian detection and has better detection results.

关键词： computer vision pedestrian detection video se-quences laser point cloud

EmotionIC: emotional inertia and contagion-driven dependency modeling for emotion recognition in conversation

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Science China(Information Sciences) 2024年第8期67卷 130-146页

作者： Yingjian liu Jiang li Xiaoping WANG Zhigang ZENG School of Artificial Intelligence and Automation Huazhong University of Science and Technology Hubei Key Laboratory of Brain-inspired Intelligent Systems Huazhong University of Science and Technology Key Laboratory of Image Processing and Intelligent Control (Huazhong University of Science and Technology) Ministry of Education Institute of Artificial Intelligence Huazhong University of Science and Technology

Emotion recognition in conversation(ERC) has attracted growing attention in recent years as a result of the advancement and implementation of human-computer interface technologies. In this paper,we propose an emotional inertia and contagion-driven dependency modeling approach(EmotionIC) for ERC tasks. Our EmotionIC consists of three main components, i.e., identity masked multi-head attention(IMMHA), dialogue-based gated recurrent unit(DiaGRU), and skip-chain conditional random field(SkipCRF).Compared to previous ERC models, EmotionIC can model a conversation more thoroughly at both the feature-extraction and classification levels. The proposed model attempts to integrate the advantages of attention-and recurrence-based methods at the feature-extraction level. Specifically, IMMHA is applied to capture identity-based global contextual dependencies, while Dia GRU is utilized to extract speaker-and temporal-aware local contextual information. At the classification level, SkipCRF can explicitly mine complex emotional flows from higher-order neighboring utterances in the conversation. Experimental results show that our method can significantly outperform the state-of-the-art models on four benchmark *** ablation studies confirm that our modules can effectively model emotional inertia and contagion.

关键词： emotion recognition in conversation emotional inertia and contagion multi-head attention gated recurrent unit conditional random field

STUDY ON PREVIEW CONTROL METHOD OF ACTIVE SUSPENSION BASED ON A HALF-CAR MODEL

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Journal of Central South University 1999年第1期11卷 52-56页

作者： Shaojun liu Yan li 1. College of Mechanical and Electrical Engineering Central South University of Technology 410083 Changsha China

Previous studies have confirmed in simulation and experiment that an improved control performance can be obtained when the optimal preview control method was applied to an active suspension system for a quarter car model. In order to investigate the effectiveness not only in riding comfort but also in road handling, an half car model with the hydro pneumatic active suspension system is proposed in this study. Whole preview control method and partial preview control method, in which the road information detected by the front wheel is sent to the controller to decide the input to rear suspension, are taken into design of the active suspension control system. Results of numerical simulation show that satisfactory control efficiency could be achieved in both whole preview control and partial preview control. The comparison of results suggests that whole preview control method can provide better system performance, but the partial preview control method is superior due to its lower cost.

关键词： active suspension whole preview control partial preview control