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11篇 您的检索式:作者名="Longjun CHEN"
    题名 作者 年代 出处 被引量
1A Strigolactone Biosynthesis Gene Contributed to the Green Revolution in Rice显示文摘Plant architecture is a complex agronomic trait and a major factor of crop yield,which is affected by several important hormones.Strigolactones(SLs)are identified as a new class hormoneinhibiting branching in many plant species and have been shown to be involved in various developmental processes.Genetical and chemical modulation of the SL pathway is recognized as a promising approach to modify plant architecture.However,whether and how the genes involved in the SL pathway could be utilized in breeding still remain elusive.Here,we demonstrate that a partial loss-of-function allele of the SL biosynthesis gene,HIGH TILLERING AND DWARF 1/DWARF17(HTD1/D17),which encodes CAROTENOID CLEAVAGE DIOXYGENASE 7(CCD7),increases tiller number and improves grain yield in rice.We found that the HTD1 gene had been widely utilized and co-selected with Semidwarf 1(SD1),both contributing to the improvement of plant architecture in modern rice varieties since the Green Revolution in the 1960s.Understanding how phytohormone pathway genes regulate plant architecture and how they have been utilized and selected in breeding will lay the foundation for developing the rational approaches toward improving crop yield.Yuexing Wang Lianguang Shang Hong Yu Longjun Zeng Jiang Hu Shen Ni Yuchun Rao Sanfeng Li Jinfang Chu Xiangbing Meng Lei Wang Ping Hu Jijun Yan Shujing Kang Minghao Qu Hai Lin Tao Wang Quan Wang Xingming Hu Hongqi Chen Bing Wang Zhenyu Gao Longbiao Guo Dali Zeng Xudong Zhu Guosheng Xiong Jiayang Li Qian Qian 2020Molecular Plant2020,13,6:23
2Implications for rock instability precursors and principal stress direction from rock acoustic experiments显示文摘The characteristics of rock instability precursors and the principal stress direction are very crucial for the prevention of geological disasters.This study investigated the qualitative relationship between rock instability precursors and principal stress direction through wave velocity in rock acoustic emission(AE)experiments.Results show that the wave velocity variation exhibits obvious anisotropic characteristics in 0%–20%and 60%–90%of peak strength due to the differences of stress-induced microcrack types.The amplitude of wave velocity variation is related to the azimuth and position of wave propagation path,which indicates that the principal stress direction can be identified by the anisotropic characteristics of wave velocity variations.Furthermore,the experiments also demonstrate that the AE event rate and wave velocity show quiet and stable variations in the elastic stage of rock samples,while they present a trend of active and unstable variations in the plastic stage.It implies that both the AE event rate and wave velocity are effective monitoring parameters for rock instability.The anisotropic characteristics of the wave velocity variation and AE event rate are beneficial complements for identifying the rock instability precursors and determining the principal stress direction,which provides a new analysis method for stability monitoring in practical rock engineering.Longjun Dong Yongchao Chen Daoyuan Sun Yihan Zhang 2021International Journal of Mining Science and Technology2021,31,5:10
3Leaching process and kinetics of manganese in low-grade manganese ore显示文摘Manganese was extracted from leaching low-grade manganese ore in sulfuric acid medium. The effects of granule diameter, leaching time, liquid/solid ratio (V/W) and the concentration of sulfuric acid were investigated through orthogonal and single factor experiments. The experimental results showed that the optimal leaching conditions are, size of 0.054mm, 120 minutes of reaction time, 3(V/W) of liquid/solid ratio and 30% of the concentration of sulfuric acid (g/g). Under those conditions, the leaching efficiency is 96.73%. The kinetics of the leaching process is in accordance with the characteristics of fractal reaction.XIE Chao XU Longjun PENG Tiefeng CHEN Kun ZHAO Jing 2013Chinese Journal Of Geochemistry2013,32,2:5
4Homoharringtonine is a safe and effective substitute for anthracyclines in children younger than 2 years old with acute myeloid leukemia显示文摘Homoharringtonine (HHT),a plant alkaloid from Cephalotaxus harringtonia,exhibits a unique anticancer mechanism and has been widely used in China to treat patients with acute myeloid leukemia (AML) since the 1970s.Trial SCMC-AML-2009 presented herein was a randomized clinical study designed based on our previous findings that pediatric AML patients younger than two years old may benefit from HHT-containing chemotherapy regimens.Patients randomized to arm A were treated with a standard chemotherapy regimen comprising mainly of anthracyclines and cytarabine (Ara-C),whereas patients in arm B were treated with HHTcontaining regimens in which anthracyclines in all but the initial induction therapy were replaced by HHT.From February 2009 to November 2015,59 patients less than 2 years old with de novo AML (other than acute promyelocytic leukemia) were recruited.A total of 42 patients achieved a morphologic complete remission (CR) after the first course,with similar rates in both arms (70.6% vs.72.0%).At the end of the follow-up period,40 patients remained in CR and 5 patients underwent hematopoietic stem cell transplantation in CR,which could not be considered as events but censors.The 5-year event-free survival (EFS) was 60.2%± 9.6% for arm A and 88.0%± 6.5% for arm B (P=0.024).Patients in arm B experienced shorter durations of leukopenia,neutropenia,and thrombocytopenia and had a lower risk of infection during consolidation chemotherapy with high-dosage Ara-C.Consequently,the homoharringtonine-based regimen achieved excellent EFS and alleviated hematologic toxicity for children aged younger than 2 years with de novo AML compared with the anthracycline-based regimen.Xiaoxiao Chen Yanjing Tang Jing Chen Ru Chen Longjun Gu Huiliang Xue Ci Pan Jingyan Tang Shuhong Shen 2019Frontiers of Medicine2019,13,3:3
5A transfer alignment method for airborne distributed POS with three-dimensional aircraft flexure angles显示文摘An airborne distributed position and orientation system(POS) appears to satisfy the requirement of multi-point motion parameters measurement. This relies on transfer alignment from a high precision master system to slave systems to obtain high accuracy motion parameters of all points. A key problem for a distributed POS involves determining a method to treat the aircraft flexure appropriately and achieve high precision transfer alignment. In this study, the effect of aircraft flexure on transfer alignment accuracy for airborne earth observation is first analyzed. Based on this, the error model of transfer alignment that considers three-dimensional flexure angles are established, and a transfer alignment based on parameter identification unscented Rauch-Tung-Striebel smoother(PIURTSS) is proposed. The simulations results show that the transfer alignment method based on PIURTSS effectively improves the estimation accuracy.Xiaolin GONG Longjun CHEN Jiancheng FANG Gang LIU 2018Science China(Information Sciences)2018,61,9:2
6Prevalence, risk factors and impact of gastroesophageal reflux disease symptoms: A population-based study in South China显示文摘Minhu Chen Lishou Xiong Huixin Chen Angao Xu Longjun He Pinjin Hu 2005Scandinavian Journal of Gastroenterology2005,,7:2
7Acoustic emission source location method and experimental verification for structures containing unknown empty areas显示文摘Acoustic emission(AE)localization plays an important role in the prediction and control of potential hazardous sources in complex structures.However,existing location methods have less discussion on the presence of unknown empty areas.This paper proposes an AE source location method for structures containing unknown empty areas(SUEA).Firstly,this method identifies the shape,size,and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE arrivals.Then,the unknown AE source can be located considering the identified empty areas.The lead break experiments were performed to verify the effectiveness and accuracy of the proposed method.Five specimens were selected containing empty areas with different positions,shapes,and sizes.Results show the average location accuracy of the SUEA increased by 78%compared to the results of the existing method.It can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels,bridges,railroads,and caves in practical engineering.Longjun Dong Qing Tao Qingchun Hu Sijia Deng Yongchao Chen Qiaomu Luo Xihong Zhang 2022International Journal of Mining Science and Technology2022,32,3:2
8PKinetics analysis of the enzymatic hydrolysis of cellulose from straw stalk显示文摘The effects of several parameters on the simultaneous saccharification and fermentation of straw stalk for ethanol fuel production were investigated on the basis of orthogonal experiments. The parameters include temperature and time of fermentation, quantity and proportion of yeast inoculation, as well as cellulase dosage. An ethanol yield of 0.183 g/g was obtained from the straw stalk pretreated with diluted acid under determined optimum conditions. These conditions were: fermentation temperature: 38℃; fermentation time: 72 h; yeast inoculation quantity: 15%; yeast inoculation proportion: 2:1; and cellulose enzyme dosage: 20 U/g. The relationship between ethanol concentration c and fermentation time t is presented as follows, c=abt/(1+bt). The rate constant k of straw stalk hydrolysis by the cellulose enzyme depends on hydrolysis time, as described by k=k1t-h. Therefore, straw stalk hydrolysis reaction by the cellulose enzyme is fractal-like.CHEN Kun XU Longjun BI Zhiming FU Zhilei 2013Chinese Journal Of Geochemistry2013,32,1:1
9Safety culture assessment of petroleum enterprises based on SMART显示文摘This paper introduces an improved fuzzy comprehensive evaluation model specially designed for the safety culture assessment of petroleum enterprises. The model is established based on the authors' years of experience in this field. The index system of the safety assessment mentioned herein is based on SMART safety culture principles, covering safety material, safety behavior, safety system, safety belief, persistence of safety, and openness of safety. The proposed system also includes the safety material culture, in which on-the-spot analysis of the key factors of safety culture is conducted together with duty consultants. All the fuzzy membership indexes and their degrees were weighed and calculated with the final evaluation results, presented in accordance with the analytic hierarchy process. All the safety culture statuses of petroleum enterprises Z, S, and C were then incorporated into detailed analysis. The results of the application confirm that the levels of safety culture follow the order of Z petroleum enterprise CHEN Kun XU Longjun YANG Rui BI Zhiming 2013Chinese Journal Of Geochemistry2013,32,3:1
10Implications for identification of principal stress directions from acoustic emission characteristics of granite under biaxial compression experiments显示文摘The rock fracture characteristics and principal stress directions are crucial for prevention of geological disasters.In this study,we carried out biaxial compression tests on cubic granite samples of 100 mm in side length with different intermediate principal stress gradients in combination with acoustic emission(AE)technique.Results show that the fracture characteristics of granite samples change from‘sudden and aggregated’to‘continuous and dispersed’with the increase of the intermediate principal stress.The effect of increasing intermediate principal stress on AE amplitude is not significant,but it increases the proportions of high-frequency AE signals and shear cracks,which in turn increases the possibility of unstable rock failure.The difference of stress in different directions causes the anisotropy of rock fracture and thus leads to the obvious anisotropic characteristics of wave velocity variations.The anisotropy of wave velocity variations with stress difference is probable to identify the principal stress directions.The AE characteristics and the anisotropy of wave velocity variations of granite under two-dimensional stress are not only beneficial complements for rock fracture characteristic and principal stress direction identification,but also can provide a new analysis method for stability monitoring in practical rock engineering.Longjun Dong Yongchao Chen Daoyuan Sun Yihan Zhang Sijia Deng 2023Journal of Rock Mechanics and Geotechnical Engineering2023,15,4:1
11Effects of silent myocardial ischemia on functional fitness and physical independence in 60–79-year-old adults显示文摘Objective:We examined the effect of silent myocardial ischemia(SMI)on functional fitness levels and physical independence in 60–79-year-old individuals.Methods:We conducted a cross-sectional study with 716 older adults and used an electrocardiograph and an ambulatory electrocardiogram to diagnose those with SMI.Physical independence was assessed using the Composite Physical Function scale,whereas physical fitness was assessed using the Senior Fitness Test battery.Results:The 60-79-year-old females and males with SMI were more likely to have lower scores for lower and upper body strength,agility/dynamic balance,and aerobic endurance(p<0.05)than those without SMI.The scores for lower and upper body flexibility in all age groups for both genders were not significant(p>0.05).Binary logistic regression analysis revealed that old adults with SMI had a higher risk of losing physical independence later in life than those without SMI(p<0.05).Conclusion:This study showed that individuals with SMI have lower fitness levels and increased risk of losing physical independence than those without SMI.Longjun Cao Linke Li Lei Wang Shen Li Yingwu Chen Shilei Yuan Liping Huang 2019Sports Medicine and Health Science2019,1,1:0
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