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Cardiac Magnetic Resonance Visualization of the Myocardial Microstructure in Non-Ischemic Cardiomyopathies
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作者 Yun Tang xuan ma +5 位作者 Zhixiang Dong Xingrui Chen Shujuan Yang Xiuyu Chen Kai Yang Shihua Zhao 《Cardiovascular Innovations and Applications》 2024年第1期672-677,共6页
Cardiac magnetic resonance(CMR),a non-radiation based type of examination,can achieve the simultaneous comprehensive multi-parameter,multi-plane,and multi-sequence evaluation of the anatomical structure of the heart;a... Cardiac magnetic resonance(CMR),a non-radiation based type of examination,can achieve the simultaneous comprehensive multi-parameter,multi-plane,and multi-sequence evaluation of the anatomical structure of the heart;and at the same time,determine systolic and diastolic function,and blood perfusion and tissue characteristics.Traditional late gadolinium enhancement imaging based on CMR reflects focal replacement fibrosis,in contrast to normal myocardial signal intensity,but cannot effectively identify diffuse myocardial fibrosis.T1 mapping and its derived extracellular volume fraction can be used to quantitatively analyze the extracellular space in myocardial tissue and evaluate diffuse myocardial interstitial fibrosis that is invisible to the naked eye.Diffusion tensor imaging reveals the direction of cardiomyocyte aggregates by quantifying the anisotropy of water molecule diffusion,and can be applied to evaluate the integrity of myocardial tissue and arrangement structure of myocardial microstructural characteristics.On the basis of the micro-motion of myocardial tissue,feature tracking analysis decomposes myocardial deformation into three dimensions of micro-mechanical changes,and can identify early systolic and diastolic dysfunction before heart enlargement or ejection fraction reduction.This Commentary discusses current research advances in these new techniques,as well as their clinical application prospects and limitations for non-ischemic cardiomyopathies. 展开更多
关键词 focal replacement fibrosisin cardiac magnetic resonance cmr non ischemic cardiomyopathies diffuse m anatomical structure late gadolinium enhancement imaging late gadolinium enhancement cardiac magnetic resonance
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Analysis of the effect of temperature and packing method on the quality and oxidative stability of walnuts in storage
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作者 xuan ma Chongbo Huang +3 位作者 Chang Zheng Fangyan Long mandi Zhao Changsheng Liu 《Oil Crop Science》 2025年第3期212-222,共11页
Walnuts are rich in a variety of nutritional components.However,due to their high content of unsaturated fatty acids(UFAs),the quality of walnuts tends to decline during storage,which adversely affects the development... Walnuts are rich in a variety of nutritional components.However,due to their high content of unsaturated fatty acids(UFAs),the quality of walnuts tends to decline during storage,which adversely affects the development of the walnut industry.This study was aimed to investigate the impacts of temperature and packaging methods on the storage quality and oxidative stability of walnuts.The Wen 185 walnut variety was selected,and the physical-chemical and nutritional indexes of walnuts stored for 42 weeks under different temperatures(18℃,4℃,and room temperature)and packaging methods(vacuum light-exposed,vacuum light-proof,vacuum-ra-diation light-exposed,vacuum-radiation light-proof,nitrogen-filled light-exposed,nitrogen-filled light-proof)were measured.The results showed that low temperatures,especially18℃,in combination with vacuum lightproof packaging,could effectively suppress the increase in oxidative stability indicators such as acid value(AV)and peroxide value(PV),and maintain high retention rates of nutritional indicators like tocopherol and phytosterol.This study has elucidated that low temperatures and appropriate packaging methods play the crucial roles in maintaining the quality and oxidative stability of walnuts during storage.It has provided comprehensive and valuable data support and theoretical basis for the scientific storage of walnuts,contributing to the devel-opment of the walnut industry and the guarantee of product quality. 展开更多
关键词 Walnut storage TEMPERATURE Packaging methods QUALITY Oxidative stability
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Performance of the CENDL-3.2 and other major neutron data libraries for criticality calculations 被引量:4
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作者 Bin Zhang Xu-Bo ma +3 位作者 Kui Hu Teng Zhang xuan ma Yi-Xue Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第1期81-97,共17页
Nuclear data are the cornerstones of reactor physics and shielding calculations.Recently,China released CENDL-3.2 in 2020,and the US released ENDF/B-VIII.0 in 2018.Therefore,it is necessary to comprehensively evaluate... Nuclear data are the cornerstones of reactor physics and shielding calculations.Recently,China released CENDL-3.2 in 2020,and the US released ENDF/B-VIII.0 in 2018.Therefore,it is necessary to comprehensively evaluate the criticality computing performance of these newly released evaluated nuclear libraries.In this study,we used the NJOY2016 code to generate ACE format libraries based on the latest neutron data libraries(including CENDL-3.2,JEFF3.3,ENDF/B-VIII.0,and JENDL4.0).The MCNP code was used to conduct a detailed analysis of fission nuclides,including^(235)U,^(233)U,and^(239)Pu,in different evaluated nuclear data libraries based on 100 benchmarks.The criticality calculation performance of each library was evaluated using three statistical parameters:δk/σ,χ^(2),and<|Δ|>.Analysis of theδk/σparameter showed that CENDL-3.1 and JENDL-4.0 both had>10 benchmarks that exceeded 3r,whereas CENDL3.2,ENDFB-VIII.0,and JEFF-3.3 had,7,5,and 4 benchmarks,respectively,exceeding 3r.The ENDF/B-VII.1 library performed best,with only two benchmarks exceeding 3r.Compared to CENDL-3.1,CENDL-3.2 offers an improvement in criticality calculations.Compared to the JEFF-3.3 and ENDF/B-VIII.0 libraries,CENDL3.2 performs better in the calculation of the^(233)U assemblies,but it performs poorly in the pusl11 series case calculation of the^(239)Pu assemblies,and thus further improvement is needed. 展开更多
关键词 Criticality calculations CENDL-3.2 ENDF/B-VIII.0 Neutron ACE library
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Microstructural Depictions of Austenite Dynamic Recrystallization in a Low-Carbon Steel:A Cellular Automaton Model 被引量:3
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作者 xuan ma Cheng-Wu Zheng +1 位作者 Xing-Guo Zhang Dian-Zhong Li 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2016年第12期1127-1135,共9页
A mesoscopic cellular automaton model that takes into account grain deformation during hot deformation has been developed to quantitatively depict the microstructural evolution of the austenite dynamic recrystallizati... A mesoscopic cellular automaton model that takes into account grain deformation during hot deformation has been developed to quantitatively depict the microstructural evolution of the austenite dynamic recrystallization (DRX) in a low-carbon steel. Both the grain deformation and the concept of DRX cycle are introduced, allowing accurate depictions of the grain structures, the overall microstructural properties and the flow stress evolutions that involving in the austenite DRX. The simulation results are compared with the experimental results and the predictions by the macroscopic DRX model and are found to be in good agreement. 展开更多
关键词 Dynamic recrystallization AUSTENITE DRX cycle Cellular automaton Mesoscopic modeling
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Modulation of Beta Oscillations for Implicit Motor Timing in Primate Sensorimotor Cortex during Movement Preparation 被引量:2
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作者 Hongji Sun xuan ma +8 位作者 Liya Tang Jiuqi Han Yuwei Zhao Xuejiao Xu Lubin Wang Peng Zhang Luyao Chen Jin Zhou Changyong Wang 《Neuroscience Bulletin》 SCIE CAS CSCD 2019年第5期826-840,共15页
Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta o... Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixedduration experiments(500 ms as the Short Group and1500 ms as the Long Group) and random-duration experiments(500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from15 Hz to 25 Hz. The beta power was higher during the hold period than the movement(reach and grasp) period.Further, in the fixed-duration experiments, the mean poweras well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention. 展开更多
关键词 MACAQUE Primary motor cortex Primary somatosensory cortex Posterior parietal cortex Temporal perception Local field potentials
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Neurons in Primary Motor Cortex Encode Hand Orientation in a Reach-to-Grasp Task 被引量:2
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作者 Chaolin ma xuan ma +1 位作者 Jing Fan Jiping He 《Neuroscience Bulletin》 SCIE CAS CSCD 2017年第4期383-395,共13页
It is disputed whether those neurons in the primary motor cortex(M1) that encode hand orientation constitute an independent channel for orientation control in reach-to-grasp behaviors. Here, we trained two monkeys t... It is disputed whether those neurons in the primary motor cortex(M1) that encode hand orientation constitute an independent channel for orientation control in reach-to-grasp behaviors. Here, we trained two monkeys to reach forward and grasp objects positioned in the frontal plane at different orientation angles, and simultaneously recorded the activity of M1 neurons. Among the 2235 neurons recorded in M1, we found that 18.7% had a high correlation exclusively with hand orientation, 15.9% with movement direction, and 29.5% with both movement direction and hand orientation. The distributions of neurons encoding hand orientation and those encoding movement direction were not uniform but coexisted in the same region. The trajectory of hand rotation was reproduced by the firing patterns of the orientation-related neurons independent of the hand reaching direction. These resultssuggest that hand orientation is an independent component for the control of reaching and grasping activity. 展开更多
关键词 Primary motor cortex Single neuron recording Hand orientation Non-human primate
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Recurrent Seizures Manifestations in a Case of Congenital Hypoparathyroidism:a Case Report
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作者 Sheng-yu Wang Wei Wu xuan ma 《Chinese Medical Sciences Journal》 CAS CSCD 2013年第4期242-244,共3页
HYPOPARATHYROIDISM is characterized by hypocalcemia, hyperphosphatemia and low or inappropriately normal levels of parathyroid hormone (PTH). PTH is a key calcium regulatinghormone essential for calcium homeostasis,... HYPOPARATHYROIDISM is characterized by hypocalcemia, hyperphosphatemia and low or inappropriately normal levels of parathyroid hormone (PTH). PTH is a key calcium regulatinghormone essential for calcium homeostasis, vitamin D-dependent calcium absorption, renal calcium reabsorption and renal phosphate clearance. Hypoparathyroidism may be due to congenital or acquired disorders. Causes include autoimmune diseases, genetic abnormalities, destruction or infiltrative disorders of the parathyroid glands. 展开更多
关键词 HYPOPARATHYROIDISM SEIZURE basal ganglia calcification
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Impact of deacidification processes on the quality and oxidative stability of walnut oil
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作者 xuan ma Chongbo Huang +3 位作者 Chang Zheng Fangyan Long mandi Zhao Changsheng Liu 《Oil Crop Science》 CSCD 2024年第4期247-254,共8页
In order to select an appropriate deacidification process and improve the quality of walnut oil,low-temperature cold-pressed crude walnut oil was used as raw material.Deacidified walnut oil was prepared using three de... In order to select an appropriate deacidification process and improve the quality of walnut oil,low-temperature cold-pressed crude walnut oil was used as raw material.Deacidified walnut oil was prepared using three deacidification processes:chemical deacidification(CD),adsorption deacidification(AD),and molecular distillation deacidification(MDD).The physicochemical properties,nutritional components,and in vitro antioxidant activities of the resulting deacidified walnut oils were comparatively analyzed.The results indicate that the fatty acid content in walnut oil exhibits fluctuating changes during the three different deacidification processes.The MDD shows a higher deacidification rate,reaching 94.06%,which is superior to the other two methods.Additionally,the AD retains more total phenols and tocopherols,with retention rates of 95.79%and 74.62%,respectively;whereas MDD is more effective at retaining phytosterols,achieving a retention rate of 98.09%.All these methods displayed positive impacts on the in vitro antioxidant capacity and oil stability of walnut oil,with ferric-reducing antioxidant power(FRAP)content and oxidative stability time were significantly reduced.-whencompared to the untreated crude oil Among them,AD had the greatest impact on oxidative stability index(OSI),with its decreasing from 2.06 h to 0.82 h.Overall,compared to CD or MDD,the AD has best application prospects in preserving nutritional components. 展开更多
关键词 Walnut oil REFINING DEACIDIFICATION ADSORPTION Oxidative stability
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A comprehensive review of bioactive compounds and processing technology of sesame seed 被引量:2
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作者 xuan ma Zhi Wang +1 位作者 Chang Zheng Changsheng Liu 《Oil Crop Science》 CSCD 2022年第2期88-94,共7页
Sesame seeds are promulgated as traditional high-quality edible oil crops,rich in lipid(40–65%),protein(19–35%),and bioactive compounds.The review starts with bioactive components(fatty acid,tocopherol,phytosterol,s... Sesame seeds are promulgated as traditional high-quality edible oil crops,rich in lipid(40–65%),protein(19–35%),and bioactive compounds.The review starts with bioactive components(fatty acid,tocopherol,phytosterol,sesamin,sesamolin,and sesamol)of sesame seeds.It considers processing techniques for extracting oil(aqueous extraction and pressing)from seeds.Novel technologies,such as enzyme-assisted aqueous,supercritical CO_(2),and microwave-assisted solvent extraction,are also discussed.The methods of utilization of sesame seed cake are also analyzed.In the future,the processing technology of sesame seed will be further developed in the direction of improving comprehensive utilization rate to meet new consumption demand. 展开更多
关键词 Sesame seed Bioactive compound Nutritional properties Processing technology BY-PRODUCT
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Effect of temperature on tribofilm growth and the lubrication of the piston ring-cylinder liner system in two-stroke marine engines 被引量:1
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作者 Xiuyi LYU Jiang HU +5 位作者 Yunchuan WANG Jinlu SHENG xuan ma Tongyang LI Chang GE Xiqun LU 《Friction》 SCIE EI CAS CSCD 2024年第8期1858-1881,共24页
This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled ana... This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature conditions.In this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent research.This study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental results.Moreover,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs. 展开更多
关键词 TRIBOFILM piston ring-cylinder liner(PRCL)system temperature comprehensive roughness two-stroke internal combustion engines(ICEs)
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An investigation of changes in water quality throughout the drinking water production/distribution chain using toxicological and fluorescence analyses
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作者 Xue Han Xin Ji +5 位作者 xuan ma Jun-Ling Liu Zhen-Yu He Wei Chang Fei Tang Ai-Lin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2020年第1期310-318,共9页
Changes in water quality from source water to finished water and tap water at two conventional drinking water treatment plants(DWTPs)were monitored.Beside the routine water quality testing,Caenorhabditis elegans-based... Changes in water quality from source water to finished water and tap water at two conventional drinking water treatment plants(DWTPs)were monitored.Beside the routine water quality testing,Caenorhabditis elegans-based toxicity assays and the fluorescence excitation–emission matrices technique were also applied.Both DWTPs supplied drinking water that met government standards.Under current test conditions,both the investigated finished water and tap water samples exhibited stronger lethal,genotoxic and reprotoxic potential than the relative source water sample,and the tap water sample was more lethal but tended to be less genotoxic than the corresponding finished water sample.Meanwhile,the nearly complete removal of tryptophan-like substances and newly generated tyrosine-like substances were observed after the treatment of drinking water,and humic-like substances were identified in the tap water.Based on these findings,toxic pollutants,including genotoxic/reproductive toxicants,are produced in the drinking water treatment and/or distribution processes.Moreover,further studies are needed to clarify the potentially important roles of tyrosine-like and humic-like substances in mediating drinking water toxicity and to identify the potential sources of these contaminants.Additionally,tryptophan-like fluorescence may be adopted as a useful parameter to monitor the treatment performance of DWTPs.Our observations provided insights into the importance of utilizing biotoxicity assays and fluorescence spectroscopy as tools to complement the routine evaluation of drinking water. 展开更多
关键词 BIOASSAY C.elegans EEM Water treatment Distribution system
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The Role of Ozone Depletion in the Lack of Cooling in the Antarctic Upper Stratosphere during Austral Winter
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作者 xuan ma Lei WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第4期619-633,共15页
Temperature trends in the upper stratosphere are investigated using satellite measurements from Stratospheric Sounding Unit(SSU)outputs and simulations from chemistry-climate models(CCMs)and the Coupled Model Intercom... Temperature trends in the upper stratosphere are investigated using satellite measurements from Stratospheric Sounding Unit(SSU)outputs and simulations from chemistry-climate models(CCMs)and the Coupled Model Intercomparison Project Phase 6(CMIP6).Observational evidence shows a lack of cooling in the Antarctic,in contrast to strong cooling at other latitudes,during austral winter over 1979-97.Analysis of CCM simulations for a longer period of1961-97 also shows a significant contrast in the upper stratospheric temperature trends between the Antarctic and lower latitudes.Results from two sets of model integrations with fixed ozone-depleting substances(ODSs)and fixed greenhouse gases(GHGs)at their 1960 levels suggest that the ODSs have made a major contribution to the lack of cooling in the Antarctic upper stratosphere.Results from CMIP6 simulations with prescribed GHGs and ozone confirm that changes in the dynamical processes associated with observed ozone depletion are largely responsible for the lack of cooling in the Antarctic upper stratosphere.The lack of cooling is found to be dynamically induced through increased upward wave activity into the upper stratosphere,which is attributed mainly to ODSs forcing.Specifically,the radiative cooling caused by the ozone depletion results in a stronger meridional temperature gradient between middle and high latitudes in the upper stratosphere,allowing more planetary waves propagating upward to warm the Antarctic upper stratosphere.These findings improve our understanding of the chemistry-climate coupling in the southern upper stratosphere. 展开更多
关键词 Antarctic stratosphere temperature trends OZONE wave activity
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Effect of autaptic delay signal on spike-timing precision of single neuron
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作者 马璇 赵鸭鸭 +2 位作者 王亚峰 陈月玲 王恒通 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期613-620,共8页
Experimental and theoretical studies have reported that the precise firing of neurons is crucial for sensory representation.Autapse serves as a special synapse connecting neuron and itself,which has also been found to... Experimental and theoretical studies have reported that the precise firing of neurons is crucial for sensory representation.Autapse serves as a special synapse connecting neuron and itself,which has also been found to improve the accuracy of neuronal response.In current work,the effect of autaptic delay signal on the spike-timing precision is investigated on a single autaptic Hodgkin–Huxley neuron in the present of noise.The simulation results show that both excitatory and inhibitory autaptic signals can effectively adjust the precise spike time of neurons with noise by choosing the appropriate coupling strength g and time delay of autaptic signalτ.The g–τparameter space is divided into two regions:one is the region where the spike-timing precision is effectively regulated;the other is the region where the neuronal firing is almost not regulated.For the excitatory and inhibitory autapse,the range of parameters causing the accuracy of neuronal firing is different.Moreover,it is also found that the mechanisms of the spike-timing precision regulation are different for the two kinds of autaptic signals. 展开更多
关键词 autapse time delay spike-timing precision
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Effects of preoperative trimetazidine application on myocardial injury indexes and oxidative stress indexes in patients with AMI after PCI
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作者 Sheng-Zhen Ye xuan ma +1 位作者 Yong Guo Ning Wang 《Journal of Hainan Medical University》 2018年第13期13-16,共4页
Objective:To investigate the effects of preoperative trimetazidine application on myocardial injury indexes and oxidative stress indexes in patients with AMI after PCI.Methods:A total of 70 patients with AMI who recei... Objective:To investigate the effects of preoperative trimetazidine application on myocardial injury indexes and oxidative stress indexes in patients with AMI after PCI.Methods:A total of 70 patients with AMI who received emergency PCI in this hospital between January 2015 and January 2018 were divided into the control group (n=35) (received no trimetazidine) and the trimetazidine group (n=35) (received trimetazidine) according to the application of trimetazidine before PCI or not. The differences in the contents of myocardial injury markers, inflammatory factors and oxidative stress indexes were compared between the two groups immediately after admission and after surgery.Results: Immediately after admission, the differences in serum levels of myocardial injury markers, inflammatory factors and oxidative stress indexes were not statistically significant between the two groups of patients. Twenty-four hours after surgery, serum myocardial injury markers CK-MB, cTnⅠ, Myo and h-FABP levels of trimetazidine group were lower than those of control group;inflammatory factors hs-CRP, Neopterin and IL-1β levels were lower than those of control group;oxidative stress index SOD level was higher than that of control group whereas MDA and LHP levels were was lower than those of control group.Conclusion: Trimetazidine treatment before PCI can effectively optimize the postoperative cardiac function and reduce the oxidative stress response in patients with AMI. 展开更多
关键词 AMI TRIMETAZIDINE PCI MYOCARDIAL INJURY OXIDATIVE stress
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Histone H4K8hib modification promotes gene expression and regulates rice immunity 被引量:1
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作者 Qiutao Xu xuan ma +10 位作者 Xuelu Wei Zhengting Chen Yuhang Duan Yuliang Ju Zhaoyun Wang Jing Chen Lu Zheng Xiaolin Chen Junbin Huang Jisen Zhang Xiaoyang Chen 《Molecular Plant》 2025年第1期9-13,共5页
Dear Editor,Histones undergo various post-translational modifications essential for transcription,DNA replication,repair,and other cellular processes(Li et al.,2018).While histone methylation and acetylation are well ... Dear Editor,Histones undergo various post-translational modifications essential for transcription,DNA replication,repair,and other cellular processes(Li et al.,2018).While histone methylation and acetylation are well studied,emerging short-chain lysine acylations,such as crotonylation,succinylation,lactylation,acetoacetylation,and 2-hydroxyisobutyrylation(Khib)(Li et al.,2018;Lu et al.,2018;Zheng et al.,2021;Gao et al.,2023),are expanding the field of epigenetic regulation.Of these short-chain acylations,Khib has garnered recent attention as an evolutionarily conserved modification on histone proteins,extensively characterized in yeast and animals,where it plays a role in glucose response and virus infection(Huang et al.,2017;Zhao et al.,2022).In plants,H4K8hib has been identified on histones,but its functions and the enzymes involved in its removal remain unclear.In this study,we analyzed the H4K8hib modification profile in rice,exploring its role in the rice immune response and identifying the enzymes responsible for its removal. 展开更多
关键词 IMMUNITY MODIFICATION EXPANDING
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Study on the tribological behaviors of the cylinder liner-piston ring in the ammonia-fueled engine
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作者 Xing Xu Chang Ge +4 位作者 Baofeng Zhang xuan ma Rui Guo Xiaolong Wang Xiqun Lu 《Friction》 2025年第6期125-136,共12页
As a hydrogen-rich carbon-free fuel,ammonia fuel has recently attracted considerable attention in the engine field.However,few studies on the tribological properties of ammonia-fueled engines have been reported,which ... As a hydrogen-rich carbon-free fuel,ammonia fuel has recently attracted considerable attention in the engine field.However,few studies on the tribological properties of ammonia-fueled engines have been reported,which limits the development of ammonia-fueled engines.In this study,the tribological behaviors of the cylinder liner‒piston ring(CLPR)were studied under dry friction,water,and ammonia solution media.The results indicated that both the water medium and the ammonia solution medium have a certain lubricating effect.The main wear mechanism of CLPR in dry friction is abrasive wear.In both the water medium and the ammonia solution medium,the surface damage to the CLPR was dominated by tribocorrosion,but their action mechanisms were completely different.The presence of ammonia causes the microelectrolytic reaction of the CLPR and changes the tribological behavior of the CLPR. 展开更多
关键词 cylinder liner piston ring tribological behaviors AMMONIA
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Transformation:how do nematode sperm become activated and crawl? 被引量:4
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作者 xuan ma Yanmei Zhao +2 位作者 Wei Sun Katsuya Shimabukuro Long Miao 《Protein & Cell》 SCIE CSCD 2012年第10期755-761,共7页
Nematode sperm undergo a drastic physiological change during spermiogenesis(sperm activation).Unlike mammalian flagellated sperm,nematode sperm are amoeboid cells and their motility is driven by the dynamics of a cyto... Nematode sperm undergo a drastic physiological change during spermiogenesis(sperm activation).Unlike mammalian flagellated sperm,nematode sperm are amoeboid cells and their motility is driven by the dynamics of a cytoskeleton composed of major sperm protein(MSP)rather than actin found in other crawling cells.This review focuses on sperm from Caenorhabditis elegans and Ascaris suum to address the roles of external and internal factors that trigger sperm activation and power sperm motility.Nematode sperm can be activated in vitro by several factors,including Pronase and ionophores,and in vivo through the TRY-5 and SPE-8 pathways.Moreover,protease and protease inhibitors are crucial regulators of sperm maturation.MSP-based sperm motility involves a coupled process of protrusion and retraction,both of which have been reconstituted in vitro.Sperm motility is mediated by phosphorylation signals,as illustrated by identification of several key components(MPOP,MFPs and MPAK)in Ascaris and the characterization of GSP-3/4 in C.elegans. 展开更多
关键词 SPERMIOGENESIS major sperm protein sperm motility
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Ordovician integrative stratigraphy and timescale of China 被引量:19
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作者 Yuandong ZHANG Renbin ZHAN +5 位作者 Yongyi ZHEN Zhihao WANG Wenwei YUAN Xiang FANG xuan ma Junpeng ZHANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2019年第1期61-88,共28页
In this chapter, starting with a brief review of the research history and current status in the studies of the Ordovician chronostratigraphy in China, the subdivision of the Ordovician System, definition and recogniti... In this chapter, starting with a brief review of the research history and current status in the studies of the Ordovician chronostratigraphy in China, the subdivision of the Ordovician System, definition and recognition of its series and stage boundaries, and possible stratigraphic gaps are discussed in details in order to establish a multidisciplinary stratigraphic correlation through an integrated approach including lithostratigraphy, biostratigraphy, radiometric dating, chemostratigraphy and magnetostratigraphy. Being internationally accepted, the Ordovician System is now subdivided into three series and seven stages, in ascending order, Lower(Tremadocian, Floian), Middle(Dapingian, Darriwilian) and Upper series(Sandbian, Katian,Hirnantian). Three of the seven "Golden Spikes" defining the bases of the Ordovician stages, which were established in 1997–2007, are located in China. As a regionally applied chronostratigraphy, the Ordovician System was subdivided in China into Lower(Xinchangian, Yiyangian), Middle(Dapingian, Darriwilian) and Upper series(Neichiashanian, Chientangkiangian,Hirnantian). This scheme agrees largely with the standard international classification, which can actually be directly applied to China, except for some special circumstances where the Neichiashanian and Chientangkiangian stages of the Upper Ordovician are used. Based on the new studies in recent years and distinctions and differences recognized in the development of the Ordovician System in the constituent terranes of China, a new framework for correlation among the major Chinese palaeoplates or terranes, e.g. South China, North China(including Tarim and Qaidam) and Xizang(Tibet)-western Yunnan, has been established. However, it has been recognized herein that uncertainties still remain on defining the base of the Tremadocian,Dapingian and Katian, and on the correlation between different mega-facies. More specifically, for the Tremadocian, the precise correlation of its base will depend on the better-defined conodont taxonomy, while for the Dapingian and Katian, on the correlation between different mega-facies. It is worthwhile to note that the chemostratigraphic studies of the Ordovician System in China produced the carbonate δ13 C curves for the Darriwilian(Middle Ordovician) and Katian(Upper Ordovician), which show significant differences from the composite global curve. Record of the Ordovician isotopic dating is relatively rare in China, with only three reliable ages from zircons that are all from the upper Katian to Hirnantian of the Upper Ordovician.Abundant bentonite beds in the Upper Ordovician of South China will also provide unique opportunities to advance the isotopic dating and related researches. Studies on the Ordovician magnetostratigraphy need to be significantly enhanced in China, as currently all the available results are restricted to the Lower Ordovician of North China, although they can be correlated with those known from other parts of the world. The analysis of the durational unevenness of the seven stages in the Ordovician supports the possibility to further subdivide the long-durational Tremadocian, Darriwilian and Katian stages, each into two substages. 展开更多
关键词 ORDOVICIAN System Geological age CHRONOSTRATIGRAPHY CHEMOSTRATIGRAPHY BIOSTRATIGRAPHY
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Extensive profiling of the expressions of tRNAs and tRNA-derived fragments(tRFs)reveals the complexities of tRNA and tRF populations in plants 被引量:7
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作者 xuan ma Chunyan Liu +5 位作者 Xiaocong Kong Jing Liu Siju Zhang Shanshan Liang Weijiang Luan Xiaofeng Cao 《Science China(Life Sciences)》 SCIE CAS CSCD 2021年第4期495-511,共17页
Evidence is emerging that t RNA-derived fragments(t RFs)are regulatory molecules.Studies of t RFs in plants have been based on conventional small RNA sequencing,and focused on profiling of t RF-5 and t RF-3 species.A ... Evidence is emerging that t RNA-derived fragments(t RFs)are regulatory molecules.Studies of t RFs in plants have been based on conventional small RNA sequencing,and focused on profiling of t RF-5 and t RF-3 species.A more comprehensive and quantitative analysis of the entire t RF population is highly necessary.Here,we employ t RNA-seq and YAMAT-seq,and develop a bioinformatics tool to comprehensively profile the expressions of t RNAs and t RFs in plants.We show that in Arabidopsis,approximately half of t RNA genes are extremely weakly expressed,accounting for only 1%of total t RNA abundance,while~12%of t RNA genes contribute to~80%of t RNA abundance.Our t RNA sequencings in various plants reveal that t RNA expression profiles exhibit a cross-species conserved pattern.By characterizing the composition of a highly heterogeneous t RF population,we show that t RNA halves and previously unnoticed 10–16-nt tiny t RFs represent substantial portions.The highly accumulated 13-nt and 16-nt tiny t RFs in Arabidopsis indicate that tiny t RFs are not random t RNA degradation products.Finally,we provide a user-friendly database for displaying the dynamic spatiotemporal expressions of t RNAs and t RFs in the model plants Arabidopsis and rice. 展开更多
关键词 TRNA tRFs tRNA halves tiny tRFs tRNA-seq
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Plant transfer RNA-derived fragments:Biogenesis and functions 被引量:5
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作者 xuan ma Chunyan Liu Xiaofeng Cao 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2021年第8期1399-1409,共11页
Processing of mature transfer RNAs(tRNAs)produces complex populations of tRNA-derived fragments(tRFs).Emerging evidence shows that tRFs have important functions in bacteria,animals,and plants.Here,we review recent adv... Processing of mature transfer RNAs(tRNAs)produces complex populations of tRNA-derived fragments(tRFs).Emerging evidence shows that tRFs have important functions in bacteria,animals,and plants.Here,we review recent advances in understanding plant tRFs,focusing on their biological and cellular functions,such as regulating stress responses,mediating plant-pathogen interactions,and modulating post-transcriptional gene silencing and translation.We also review sequencing strategies and bioinformatics resources for studying tRFs in plants.Finally,we discuss future directions for plant tRF research,which will expand our knowledge of plant non-coding RNAs. 展开更多
关键词 tRFs tRNA halves RNase T2 stress gene silencing PLANT
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