|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Overexpression of microRNA-124 promotes the neuronal differentiation of bone marrow-derived mesenchymal stem cells显示文摘microRNAs(miRNAs) play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124(miR-124) overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesenchymal stem cells, neural stem cells and neurons. miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We constructed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers β-III tubulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These results suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury. | Defeng Zou Yi Chen Yaxin Han Chen Lv Guanjun Tu | 2014 | Neural Regeneration Research2014，9，12： | 15 |
| 2 | Research 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 | 2019 | Rice science2019，26，1： | 13 |
| 3 | Root morphology in response to nitrogen supply in mid-season indica rice cultivars released in different decades显示文摘Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differences in growth period and pattern between the old and new rice cultivars,it is difficult to clarify how genetic improvements contribute to root growth in rice.For example,for a solution culture system,Wu et al.suggested that total root length increased with increasing year of release for maize hybrids,while shoot dry weight, | Yikai Zhang Huizhe Chen Yuping Zhang Jing Xiang Guangmei Ji Defeng Zhu | 2017 | Science China(Life Sciences)2017，60，4： | 7 |
| 4 | Decrement 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 | 2020 | Rice science2020，27，1： | 6 |
| 5 | Raman micro-spectrometry as a technique for investigating heterogeneous reactions on individual atmospheric particles显示文摘Investigating the heterogeneous reaction on individual atmospheric particles is important because it approximates actual atmospheric conditions and can aid in reducing artifacts in elucidating real mechanisms and processes,and determining real kinetic parameters of the atmosphere relevance.This study developed a Raman microspectrometry method to investigate heterogeneous reactions on individual particles.The method was applied to the reaction of NO2 with individual CaCO3 particles.It was demonstrated that Raman microspectrometry can obtain information on both chemical composition and microscopic morphology at the same time,as well as information on chemical characteristics,such as the phase,which is useful for studying reaction processes.Raman spectra of individual particles deposited on a substrate showed no interference by morphological resonance,which is helpful for obtaining high-quality spectra.Moreover,Raman microspectrometry was compared with other methods for investigating heterogeneous reactions on individual particles and was found to have several advantageous characteristics. | ZHAO DeFeng,ZHU Tong,CHEN Qi,LIU YingJun & ZHANG ZeFeng State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering,Peking University,Beijing 100871,China | 2011 | Science China Chemistry2011，54，1： | 5 |
| 6 | TOF–SIMS surface analysis of chemical components of size–fractioned urban aerosols in a typical heavy air pollution event in Beijing显示文摘Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–flight secondary ion mass spectrometry(TOF–SIMS).The variation characteristics of the surface chemical composition and influencing factors were studied, and the possible sources of these chemical compositions were identified through principal component analysis. The results showed that inorganic components such as crustal elements and sulfate, and organic components such as aliphatic hydrocarbons and oxygen–containing organic groups were present. Some surface components, such as polycyclic aromatic hydrocarbons, heavy metals and fluorides may exert adverse effects on human health. The species and relative percentages of the chemical components varied with particle size, diurnal and pollution progress. During a heavy pollution event, the species and relative percentages of secondary components such as oxygen–containing organic groups and sulfurous compounds increased, indicating that particles aged during this event. The surface chemical composition of the aerosol particles was affected mainly by emissions from coal combustion and motor vehicles. In addition, air pollution, meteorological factors, and air mass transport also exerted a significant effect on the surface chemical composition of aerosol particles. | Wenjun Li Hong Li Jinjuan Li Xueli Cheng Zhengzheng Zhang Fahe Chai Hao Zhang Ting Yang Pengli Duan Defeng Lu Yizhen Chen | 2018 | Journal of Environmental Sciences2018，30，7： | 2 |
| 7 | Atrophy 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 | 2013 | Neural Regeneration Research2013，8，4： | 2 |
| 8 | Characteristics of hydrolyzed layer and contamination on fused silica induced during polis- hing显示文摘 | Liao Defeng Chen Xianhua Tang Caixue | 2014 | Ceramics International2014，40，： | 1 |
| 9 | Global and superlinear convergence of the smoothing Newton method and its application to general box constrained variational inequalities 显示文摘 | Chen X Qi Liqun Sun Defeng | 1998 | Mathematics of Computation1998，67，： | 1 |
| 10 | Fabrication of large-area uniform carbon nanotube foams as near-critical-density targets for laser–plasma experiments显示文摘Carbon nanotube foams(CNFs)have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons.Here we report the recent advances in the fabrication technique of such targets.With the further developed floating catalyst chemical vapor deposition(FCCVD)method,large-area(>25 cm^(2))and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets.The density and thickness of the CNF can be controlled in the range of 1−13 mg/cm^(3)and 10−200µm,respectively,by varying the synthesis parameters.The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time. | Pengjie Wang Guijun Qi Zhuo Pan Defeng Kong Yinren Shou Jianbo Liu Zhengxuan Cao Zhusong Mei Shirui Xu Zhipeng Liu Shiyou Chen Ying Gao Jiarui Zhao Wenjun Ma | 2021 | High Power Laser Science and Engineering2021，9，2： | 1 |
| 11 | New lower bounds on eigenvalue of the Hadamard product of an M-matrix and its inverse显示文摘 | LI Yaotang CHEN Fubin WANG Defeng | 2009 | Linear Algebra Appl2009，430，： | 1 |
| 12 | New lower bounds on eigenvalue of the Hadamard product of an M-matrix and its inverse显示文摘 | LI Yaotang CHEN Fubin WANG Defeng | 2009 | Linear Algebra Appl2009，430，： | 1 |
| 13 | New lower bounds on eigenvalue of the Hadamard product of an matrix and its inverse显示文摘 | LI Yaotang CHEN Fubing WANG Defeng | 2009 | Linear Algebra Appl2009，430，： | 1 |
| 14 | An approach to increasing the resolution of industrial CT images based on an aperture collimator显示文摘 | Yining Zhu Defeng Chen Yunsong 2hao Hongwei Li Peng Zhang | 2013 | Optics Express2013，21，27： | 1 |
| 15 | A UNIFIED ALGORITHMIC FRAMEWORK OF SYMMETRIC GAUSS-SEIDEL DECOMPOSITION BASED PROXIMAL ADMMS FOR CONVEX COMPOSITE PROGRAMMING显示文摘This paper aims to present a fairly accessible generalization of several symmetric Gauss-Seidel decomposition based multi-block proximal alt ernating direction met hods of multipliers(ADMMs)for convex composite optimization problems.The proposed method unifies and refines many constructive techniques that were separately developed for the computational efficiency of multi-block ADMM-type algor计hms.Specifically,the majorized augmented Lagrangian functions,the indefinite proximal terms,the inexact symmetrie Gauss-Seidel decomposition theorem,the tolerance criteria of approximately solving the subproblems,and the large dual step-lengths,are all incorporated in one algoi?计hmic framework,which we named as sGS-imiPADMM.From the popularity of convergent variants of multi-block ADMMs in recent years,especially for high-dimensional multi-block convex composite conic programming problems,the unification presen ted in this paper,as well as the corresponding convergence results,may have the great potential of facilitating the implemen tation of many multi-block ADMMs in various problem set tings. | Liang Chen Defeng Sun Kim-Chuan Toh Ning Zhang | 2019 | Journal of Computational Mathematics2019，37，6： | 1 |
| 16 | Molecular 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 | 1998 | Chinese Science Bulletin1998，43，1： | 0 |
| 17 | Allylation and alkylation of oxindoleketimines via imine umpolung strategy显示文摘When treated with an alkoxide base like t-BuOK in aprotic solvent,N-di phenyl methyl imino oxindoles,made conveniently through condensation of corresponding isatins with N-di phenyl methyl amine,are deprotonated to form azaallyl anions.Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles.Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles.The overall transformation equals to an umpolung process at the C3 of isatins. | Mei-Hua Shen Chen Li Qing-Song Xu Bin Guo Rui Wang Xiaoqian Liu Hua-Dong Xu Defeng Xu | 2021 | Chinese Chemical Letters2021，32，7： | 0 |
| 18 | Overlapped Tray Seedling Raising Model for Mechanical Transplanting of Rice显示文摘With the development of China's social economy,transfer of rural labors,and rise of labor costs,the rice production technologies are changing from manual operation to mechanical operation.The core of mechanical rice production is mechanical planting,while the key to mechanical planting is the seedling raising.On the basis of analyzing and studying the problems and experience of traditional mechanical transplanting of rice,a new overlapped tray seedling raising model was introduced.Main features of this model: substrate seedling raising and overlapped seedling tray.The seedling trays for seeding line are overlapped,and the overlapped trays are moved into the seedling room with controlled temperature and humidity.The temperature of the seedling room is controlled at 30-32℃,and the humidity of the seedling room is controlled at above 90%.After about 48 h,when the seedling height reaches 0.5 cm,move the seedling trays to the nursery.This model consists of one seeding center( seedling raising center) and N nurseries,to realize 1 + N seedling raising for mechanical transplanting of rice.One seeding center can provide seedlings for several hundred to several thousand hectares of mechanical transplanting of rice,and provide a new model for social services.This model could improve the quality of seedlings,increase the seedling survival rate by about 20%,reduce the seedling raising costs by 15%-20%,reduce the seedling raising risks,and greatly increase the utilization rate of the site and equipment of seedling raising center. | Defeng ZHU Yuejun WANG Huizhe CHEN Yicheng XU Yiping CHEN | 2019 | Asian Agricultural Research2019，11，1： | 0 |
| 19 | Synchronous post-acceleration of laser-driven protons in helical coil targets by controlling the current dispersion显示文摘Post-acceleration of protons in helical coil targets driven by intense,ultrashort laser pulses can enhance ion energy by utilizing the transient current from the targets’self-discharge.The acceleration length of protons can exceed a few millimeters,and the acceleration gradient is of the order of GeV/m.How to ensure the synchronization between the accelerating electric field and the protons is a crucial problem for efficient post-acceleration.In this paper,we study how the electric field mismatch induced by current dispersion affects the synchronous acceleration of protons.We propose a scheme using a two-stage helical coil to control the current dispersion.With optimized parameters,the energy gain of protons is increased by four times.Proton energy is expected to reach 45 MeV using a hundreds-of-terawatts laser,or more than 100 MeV using a petawatt laser,by controlling the current dispersion. | Zhipeng Liu Zhusong Mei Defeng Kong Zhuo Pan Shirui Xu Ying Gao Yinren Shou Pengjie Wang Zhengxuan Cao Yulan Liang Ziyang Peng Jiarui Zhao Shiyou Chen Tan Song Xun Chen Tianqi Xu Xueqing Yan Wenjun Ma | 2023 | High Power Laser Science and Engineering2023，11，4： | 0 |
| 20 | Origin of CO_2 gas from the north depression of the middle fault zone in the Hailar-Tamtsag Basin and natural gas in nearby depressions显示文摘Natural gas pools with the high contents of CO2 were discovered during exploring the middle fault zone of the Hailar-Tamtsag Basin. So far this kind of gas reservoir with CO2 with characteristics of carbon isotope is spe-cial. The stable carbon isotope of CO2 in the study area is relatively light with δ13 CCO2 values ranging from -13.1‰ to -8.2‰. The 40Ar/36Ar values of associated argon gas range from 916 to 996, with R/Ra of 1.20-1.26. Based on comprehensive analysis, it is believed that the CO2 gas in this study area is of crust mantle source. | ZHANG Tonglei CHEN Jianfa ZHU Defeng ZHANG Chen | 2012 | Chinese Journal Of Geochemistry2012，31，1： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员