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9篇 您的检索式:作者名="Shi Defeng"
    题名 作者 年代 出处 被引量
1Research Progress on Heat Stress of Rice at Flowering Stage显示文摘Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.WANG Yaliang WANG Lei ZHOU Jianxia HU Shengbo CHEN Huizhe XIANG Jing ZHANG Yikai ZENG Yongjun SHI Qinghua ZHU Defeng ZHANG Yuping 2019Rice science2019,26,1:13
2Decrement of Sugar Consumption in Rice Young Panicle Under High Temperature Aggravates Spikelet Number Reduction显示文摘Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase(EC3.2.1.26) and sucrose synthase(EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.WANG Yaliang ZHANG Yikai SHI Qinghua CHEN Huizhe XIANG Jing HU Guohui CHEN Yanhua WANG Xiaodan WANG Junke YI Zihao ZHU Defeng ZHANG Yuping 2020Rice science2020,27,1:6
3Effect of acupotomy on chondrocyte proliferation and expression of CyclinD1,CDK4 and CDK6 in rabbits with knee osteoarthritis显示文摘Objective:The aim of this study was to investigate the mechanism of acupotomology(Apo)in the prevention of articular cartilage destruction via the promotion of chondrocyte proliferation and chondrocyte expression of cell cycle regulators,CyclinD1,CDK4 and CDK6 in a rabbit knee osteoarthritis(KOA)model.Methods:Twenty-eight rabbits were randomly divided into a control group,an OA(osteoarthritis)model group,an Apo(acupotomology)group and EA(electro-acupuncture)group(n Z 7).Improved Videman’s method was used to induce a rabbit model of KOA over 6 weeks.One week later,acupotomy and electro-acupuncture therapy was applied to animals in the respective groups and treatment lasted 4 weeks.Following these treatments,quantitative real-time PCR,immunohistochemical staining and western blotting were performed to assess the mRNA and protein levels of cell cycle regulators CyclinD1(Cell cycle protein D1),CDK4(Cyclin-dependent kinase 4)and CDK6(Cyclin-dependent kinase 6).Ethology measures and knee morphology were also compared among groups.Results:The Lequesne MG index score of morphology was increased(P<.01),and the passive range of motion(PROM)and the mRNA and protein levels of CyclinD1,CDK4,and CDK6 were significantly decreased(P<.01)in the OA model compared with the control group.The Lequesne MG index score and the morphology score were decreased in the Apo and EA group compared with the OA model group(P<.05 or P<.01),while the mRNA levels of CyclinD1,CDK4,and CDK6,and the protein levels of CDK4 were increased in the Apo and EA groups compared with the OA model group(P<.05 or P<.01).The PROM,and the protein levels of CyclinD1 and CDK6 were increased(P<.05)in the Apo group compared with the OA model group,while the PROM and the protein levels of CyclinD1 and CDK6 in the EA group were not significantly different(P>.05).Compared with the EA group,the morphology score was decreased in Apo group(P<.05).Conclusions:The mRNA levels of CyclinD1 and CDK4,and the protein level of CDK4 in chondrocytes are regulate by both Apo and EA.Apo is more effective than EA in regulating the protein levels of CyclinD1 and CDK6.According to the observed changes in morphology and cytokine levels,acupotomy can promote chondrocyte proliferation and can alleviate the destruction of articular cartilage in a model of KOA.Yang Gao Tong Wang Wei Zhang Xiaowei Shi Shining Ma Lijuan Wang Shuai Zhou Defeng Wang Meyer Magali Changqing Guo 2019Journal of Traditional Chinese Medical Sciences2019,6,3:2
4Atrophy of the left dorsolateral prefrontal cortex is associated with poor performance in verbal fluency in elderly poststroke women显示文摘This study aimed to investigate the association between atrophy in the prefrontal cortex with executive function and verbal fluency in elderly male and female patients poststroke.Thirty elderly female patients with non-aphasic ischemic stroke aged ≥ 60 years and 30 age-matched non-aphasic male patients with ischemic stroke were recruited.Automatic magnetic resonance imaging segmentation was used to assess the volume of the whole prefrontal cortex,along with its subdivisions:anterior cingulate cortex,orbitofrontal cortex and dorsolateral prefrontal cortex.The Semantic Verbal Fluency Test was administered at 3 and 15 months poststroke.At 3 months poststroke,left dorsolateral prefrontal cortex volume was significantly correlated with Verbal Fluency Test score in female patients only(partial coefficient = 0.453,P = 0.045),after controlling for age,education,diabetes,neurological deficit,white matter lesions volume,as well as the location and volume of infarcts.At 15 months poststroke,there remained a significant association between the left dorsolateral prefrontal cortex volume and Verbal Fluency Test(partial coefficient = 0.661,P = 0.001) and between the left prefrontal cortex volume and Verbal Fluency Test(partial coefficient = 0.573,P = 0.004) in female patients after the same adjustments.These findings indicate that atrophy of the left dorsolateral prefrontal cortex contributes to the impairment of verbal fluency in elderly female patients with stroke.Sex differences may be present in the neuropsychological mechanisms of verbal fluency impairment in patients with stroke.Yang-Kun Chen Wei-Min Xiao Defeng Wang Lin Shi Winnie CW Chu Vincent CT Mok Ka Sing Wong Gabor S Ungvari Wai Kwong Tang 2013Neural Regeneration Research2013,8,4:2
5Automated quantifica- tion of white matter lesion in magnetic resonance imaging of patients with acute infarction 显示文摘Lin Shi Defeng Wang Shangping 2013Journal of neuroscience methods2013,213,1:1
6Electrospinning of poly (trimethylene terephthalate)/carbon nanotube composites显示文摘Defeng Wu Tiejun Shi Tao Yang 2011European Polymer Journal2011,47,:1
7Molecular mechanism of the inhibitory effect of methylation outside the recognition sequence of restriction endonuclease Pvu Π on its cleavage activity显示文摘In 1991, we found that methylation outside the PvuⅡ recognition sequence could partially inhibit its cleavage activity. To clarify the molecular mechanism, three plasmids with different methylation states were constructed. Then, together with the original one, four plasmids were digested with different amounts of PvuⅡ. Results show that methylation on both sites results in 90% inhibition; moving the methylated site one base further away decreases the inhibitory effect to about 30%; with the adjacent dam methylation site eliminated, the inhibitory effect disappears. The data suggest that the inhibition of cleavage activity caused by outside methylation is not 'all or none', and the degree of inhibition is dependent on the position and the number of methylated bases.CHEN Defeng, SUN Mei, LIU Yingmiao, SHI Guoli and CHEN Yawen Institute of Molecular Biology, Nankai University, Tianjin 300071, China 1998Chinese Science Bulletin1998,43,1:0
8Multi-criteria comparative analysis of the pressure drop on coal gangue fly-ash slurry at different parts along an L-shaped pipeline显示文摘Disposing of coal gangue and fly-ash on the surface is a risky method with tremendous potential catastrophic consequences for the environment.Backfill mining is a promising practice for turning those hazardous wastes into functional backfill materi-als.Unfortunately,how to efficiently deliver the slurry to the desired places remains under-researched.To address this issue,the computational fluid dynamics software Fluent was used in the current study in addition to a laboratory rheological test to simulate the impact of various parameters on the evolution of pressure at a particular section of the pipeline.Furthermore,the response surface method was employed to investigate how the various components and their corresponding influencing weights interact to affect the pressure drop.This study demonstrates that the pressure drop of the slurry is highly influenced by slurry concentration,speed,and pipe diameter.While conveying speed is the main component in the bend section,pipe diameter takes over in the horizontal and vertical pipe sections.Defeng Wang Dengwu Jiao Zhanbo Cheng Qingwen Shi Helmut Mischo 2023International Journal of Coal Science & Technology2023,10,2:0
9Bulk GaN-based SAW resonators with high quality factors for wireless temperature sensor显示文摘Surface acoustic wave(SAW)resonator with outstanding quality factors of 4829/6775 at the resonant/anti-resonant frequencies has been demonstrated on C-doped semi-insulating bulk GaN.The impact of device parameters including aspect ratio of length to width of resonators,number of interdigital transducers,and acoustic propagation direction on resonator performance have been studied.For the first time,we demonstrate wireless temperature sensing from 21.6 to 120℃ with a stable temperature coefficient of frequency of–24.3 ppm/℃ on bulk GaN-based SAW resonators.Hongrui Lv Xianglong Shi Yujie Ai Zhe Liu Defeng Lin Lifang Jia Zhe Cheng Jie Yang Yun Zhang 2022Journal of Semiconductors2022,43,11:0
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