期刊文献+
共找到1,529篇文章
< 1 2 77 >
每页显示 20 50 100
A randomized trail comparing primary percutaneous coronary intervention with a strategy of short-acting thrombolysis and immediate planned primary percutaneous coronary intervention in acute myocardial infarction
1
作者 傅向华 《介入放射学杂志》 CSCD 2003年第S1期151-,共1页
Objective This study was to evaluate the efficacy and safety of a short acting reduced dose fibrinolytic regimen to promote early infarct related artery (IRA) patency for acyute myocardial infarction (AMI) patients re... Objective This study was to evaluate the efficacy and safety of a short acting reduced dose fibrinolytic regimen to promote early infarct related artery (IRA) patency for acyute myocardial infarction (AMI) patients referred for percutaneous coronary intervention (PCI).Methods Following aspirin and heparin, 166 patients were randomized to a 50 mg bolus of recombinant tissue type plasminogen activator(rt PA) or to a same volume sodium chloride injection followed by immediate primary PCI. The end points included patency rates on catheterization laboratory (cath lab) arrival, revascularization results when PCI was performed, complication rates, left ventricular function and restored patency rate following PCI. Results Patency on cath lab arrival was 64% with rt PA (34% TIMI 3,30% TIMI 2), while 31% of placebo (13% TIMI 3, 18% TIMI 2). There was no difference in the restored TIMI 3 rates of IRA between the two groups (85% vs 87%). No difference were observed in stroke or major bleeding. Left ventricular function was similar in both groups (52±9% vs 50±8%), but left ventricular ejection fraction fraction (LVEF) was higher with patent IRA (TIMI 3) on cath lab arrival than that of others (56±12% vs 48±10%).Conclusions Strategy thrombolytic regimens were compatible with subsequent PCI lead to more frequenc early recanalization (before cath lab arrival), which facilitates greater left ventricular function preservation with no augmentation of adverse events. 展开更多
关键词 in of A randomized trail comparing primary percutaneous coronary intervention with a strategy of short-acting thrombolysis and immediate planned primary percutaneous coronary intervention in acute myocardial infarction with
暂未订购
An Audio Zero-Watermark Scheme Based on Energy Comparing 被引量:7
2
作者 YANG Yu LEI Min +3 位作者 CHENG Mingzhi LIU Bohuai LIN Guoyuan XIAO Da 《China Communications》 SCIE CSCD 2014年第7期110-116,共7页
Zero-watermark technique,embedding watermark without modifying carriers,has been broadly applied for copyright protection of images.However,there is little research on audio zerowatermark.This paper proposes an audio ... Zero-watermark technique,embedding watermark without modifying carriers,has been broadly applied for copyright protection of images.However,there is little research on audio zerowatermark.This paper proposes an audio zero-watermark scheme based on energy relationship between adjacent audio sections.Taking use of discrete wavelet transformation(DWT),it gets power approximations,or energies,of audio segments.Then,it extracts the audio profile,i.e.the zero-watermark,according to the relative size of energies of consecutive fragments.The experimental results demonstrate that the proposed scheme is robust against general malicious attacks including noise addition,resampling,low-pass filtering,etc.,and this approach effectively solves the contradiction between inaudibility and robustness. 展开更多
关键词 zero-watermark audio water-marking scheme energy comparing
在线阅读 下载PDF
Comparing the rhythm and frequency of heart,breathing and knee movement in Tai Chi Chuan
3
作者 魏珊珊 刘宇 李立 《医用生物力学》 EI CAS CSCD 2009年第S1期150-151,共2页
Background:The basic exercise involved in TCC is a series of individual movements that are linked together in a continuous manner and that flow smoothly from one movement to another.Deep breathing and mental concentra... Background:The basic exercise involved in TCC is a series of individual movements that are linked together in a continuous manner and that flow smoothly from one movement to another.Deep breathing and mental concentration are also required to achieve harmony 展开更多
关键词 comparing the rhythm and frequency of heart breathing and knee movement in Tai Chi Chuan
原文传递
Preparative Resolution of Gatifloxacin Enantiomers with Pre-Column Esterification Strategy and Comparing Their Enantioselectivity to Bacteria and Antibody 被引量:1
4
作者 ZHANG Chi Jian LEI Hong Tao +4 位作者 HUANG Xiao Long LIU Ying Ju CAI Kai XU Zhen Lin SUN Yuan Ming 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第2期157-160,共4页
Gatifloxacin (GFX) is a kind of chiral fluoroquinolones compound due to the methyl group at the C-3 position of the piperazine ring[1]. Although the enantiomers of GFX show similar levels of antimicrobial activity a... Gatifloxacin (GFX) is a kind of chiral fluoroquinolones compound due to the methyl group at the C-3 position of the piperazine ring[1]. Although the enantiomers of GFX show similar levels of antimicrobial activity and pharmacokinetics[2], the other biological activities (i.e., toxicity or enantioselective recognition to various receptors in vivo) of GFX enantiomers have not yet been studied. With this in mind, we developed a rapid and cost-effective high performance liquid chromatographic (HPLC) separation procedure for GFX enantiomers with a pre-column esterification strategy. 展开更多
关键词 Preparative Resolution of Gatifloxacin Enantiomers with Pre-Column Esterification Strategy and comparing Their Enantioselectivity to Bacteria and Antibody DEA than
暂未订购
Comparing of Aviation Network Structure of Mid-south,Northwest and Southwest of China Based on Hierarchical Index Model 被引量:1
5
作者 Cheng Xiangjun Yang Fang Xie Li 《Journal of Traffic and Transportation Engineering》 2020年第1期14-19,共6页
In order to compare the aviation network of mid-south,northwest and southwest of China to reveal the structure similarity and difference for providing quantitative evidence to construct regional aviation network and i... In order to compare the aviation network of mid-south,northwest and southwest of China to reveal the structure similarity and difference for providing quantitative evidence to construct regional aviation network and improve its structure,hierarchical index model of regional aviation network was established through dividing the aviation network into layers to research its structure characters.Data matrixes were defined to record the basic state of regional aviation network.Index matrixes were constructed to describe the quantitative features of regional aviation network.On the basis of these indexes,several structure indexes of all layers of aviation network were calculated to show the structure features of aviation network,such as ratio of passenger volume within the region with across the region,share rate of passenger volume among layers,ratio of average number of airline for each airport,ratio of average passenger volume for each airline and ratio of airline rate.According to the statistical data,similar structure of share rate of passenger volume among layers and average passenger volume for each airline in their regional aviation network was found after calculating.But on the side of ratio of passenger volume within the region with across the region,ratio of average number of airlines for each airport and ratio of airline rate were different. 展开更多
关键词 Regional aviation network comparing of structure hierarchical index model index matrix structure index
在线阅读 下载PDF
Bleeding risk comparing targeted low-dose heparin with bivalirudin in patients undergoing percutaneous coronary intervention results from a propensity score-matched analysis of the evaluation of drug-eluting stents and ischemic events (EVENT) registry 被引量:1
6
《South China Journal of Cardiology》 CAS 2011年第4期271-272,共2页
Background Prior randomized trials have shown reduced bleeding with bivalirudin compared with unfractionated heparin (UFH) in patients undergoing percutaneous coronary intervention (PCI). However, it is not known ... Background Prior randomized trials have shown reduced bleeding with bivalirudin compared with unfractionated heparin (UFH) in patients undergoing percutaneous coronary intervention (PCI). However, it is not known if this benefit is also present when UFH doses are more tightly controlled (as measured by activated clotting time, ACT). 展开更多
关键词 UFH Bleeding risk comparing targeted low-dose heparin with bivalirudin in patients undergoing percutaneous coronary intervention results from a propensity score-matched analysis of the evaluation of drug-eluting stents and ischemic events EVENT REGISTRY
原文传递
Comparing the Effectiveness of Coatings on Carbide andCermet Cutting Tool Inserts
7
作者 K.H. W.Seah M.Rahman and C.H.Lee (Dept. of Mech. & Prod. Eng., National University of Singapore, 10 Kent Ridge Crescent, Singapore 0511 T.N.Goh (Dept. of Ind. & Sys. Eng., National University of Singapore, 10 Kent Ridge Crescent, Singapore 0511) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第4期269-275,共7页
A series of metal cutting experiments was performed on a CNC lathe to evaluate the performance of various coatings on different tool substrates. The workpiece material was plain medium carbon steel and the cutting too... A series of metal cutting experiments was performed on a CNC lathe to evaluate the performance of various coatings on different tool substrates. The workpiece material was plain medium carbon steel and the cutting tool materials were carbide and cermet inserts coated with various single as well as multilayer coatings. Machining was done under various cutting conditions of speed and feed-rate, and for various durations of Cutting. The output parameters studied were the cutting forces (axial, radial and tangential), the surface roughness of the workpiece, as well as the tool wear (crater and flank wear). From these results, the performances of the various cutting inserts are evaluated and compared. Results show that cutting forces are significantly lower when using coated cermets than when using coated carbides although different coatings on the same substrate also result in different cutting forces. However, there is less difference in the surface roughness of the finished workpiece for the various coatings and substrates. 展开更多
关键词 TOOL comparing the Effectiveness of Coatings on Carbide andCermet Cutting Tool Inserts
在线阅读 下载PDF
Comparing a small gravel-less perforated pipe leach fields (GPPLF) to a medium one in treating domestic sewage
8
作者 Yiheng Yang Chengduan Wang Zhenhua Dang 《Natural Science》 2012年第3期192-197,共6页
There were obvious differences between a medium gravel-less perforated pipe leach fields and a small system in the treatment of demestic sewage with the change of influent quality. In small system, COD removal rate wa... There were obvious differences between a medium gravel-less perforated pipe leach fields and a small system in the treatment of demestic sewage with the change of influent quality. In small system, COD removal rate was 91%, ammonia nitrogen removal rate was 90%, total nitrogen was 58%. In medium system, COD removal rate was 86.07%, ammonia nitrogen removal rate was 45.3%, and total nitrogen was 48.2%. This paper studied on the differences. Its main reasons were as follows: differences in opening rate (perforated area account of the total area in infiltration pipe), air flow conditions, exterior environment, and wastewater distribution. Considering those problems, Solutions and applications for the development of GPPLF are given. 展开更多
关键词 Gravel-Less Perforated PIPE LEACH FIELDS Pollutants Removal Rate comparing Component Formatting Style STYLING Insert
暂未订购
Comparing Coordination Abilities of 10-11 Years Old Girls Practicing Basketball and Rhythmic Gymnastic
9
作者 Georgi Venelinov Brestnichki 《Journal of Sports Science》 2015年第3期134-137,共4页
The words---coordination, coordination abilities and coordination training are getting more and more popular among the coaches in different sports. The rhythm makes the movement logical, easy and correct done. The pur... The words---coordination, coordination abilities and coordination training are getting more and more popular among the coaches in different sports. The rhythm makes the movement logical, easy and correct done. The purpose of this study is to determine any difference between the coordination abilities of 10-11 years old gifts practicing basketball and rhythmic gymnastics. In that study, we have tested 40 girls at the age of 10-11 years practicing basketball and rhythmic gymnastic. We have tested them by 7 coordination tests. The results from the tests have been calculated in math-statistic methods and we have used descriptive statistic and t-test by Student with guaranteed probability Pt 〉 95 %. Ten-eleven old girls practicing rhythmic gymnastic have advantage against the girls practicing basketball in all 7 tests examining coordination abilities. The girls practicing rhythmic gymnastic, guaranteed by statistic, have better results in the balance and rhythmic abilities than the girls practicing basketball game. That statement is showing us that at this age the rhythmic gymnastic or elements from rhythmic gymnastic should be used for developing balance and rhythmic ability, which are very important for the basketball game. 展开更多
关键词 comparing COORDINATION 10-11 years old GIRLS BASKETBALL rhythmic GYMNASTICS
在线阅读 下载PDF
Comparing blood security from nonprofit voluntary and profit blood donor
10
《中国输血杂志》 CAS CSCD 2001年第S1期327-,共1页
关键词 comparing blood security from nonprofit voluntary and profit blood donor
暂未订购
Comparing High-resistance Grounding Method with Resonance Grounding Method for Large Generators
11
作者 Yao Huannian Cao Meiyue(Xiamen Electric Power Administration) 《Electricity》 1997年第3期22-25,共4页
For large generators, the problem of high-resistance grounding method and the advantages of resonance, grounding method are discussed in detail, and an overall comparison is given in this paper. It is recommended that... For large generators, the problem of high-resistance grounding method and the advantages of resonance, grounding method are discussed in detail, and an overall comparison is given in this paper. It is recommended that the latter should be adopted so as to increase the operation reliability of large generators and power systems. 展开更多
关键词 HIGH comparing High-resistance Grounding Method with Resonance Grounding Method for Large Generators
在线阅读 下载PDF
A randomized double-blind multicenter study on comparing levonorgestrel and mifepristone for emergency contraception
12
作者 吴尚纯 王翠萍 +6 位作者 王幼劬 程渭玉 左诗慧 李红 徐晓 汪蓉芬 董敬 《生殖医学杂志》 CAS 1999年第S1期43-46,共4页
Objective: To compare the efficacy and side effects of levonorgestrel and low dose mifepristone in emergency contraception. Method: The study is a randomized double--blind multicenter comparative trial. A total of 1, ... Objective: To compare the efficacy and side effects of levonorgestrel and low dose mifepristone in emergency contraception. Method: The study is a randomized double--blind multicenter comparative trial. A total of 1, 276 women with unprotected intercourse within 72 hours were allocated to one of the two study groups. In the levonorgestrel (LNG) group, 0. 75 mg LNG was taken twice, 12 hours apart, whereas in the mifepristone (Mife) group, a single dose of 10 mg mifepristone was taken and a placebo 12 hours after. Follow--up visit was paid on the seventh day of the expected next menstruation to evaluate the contraceptive efficacy and side effects. Contraceptive efficacy was calculated by Dixon’s method. Result:In the LNG group 20 pregnancies occurred among 643 women, while in the Mife group 9 pregnancies occurred among 633 women. The pregnancy rates were 3. 10% and 1. 43% respectively. Contraceptive efficacy rate of preventing pregnancy was 59. 16% and 79. 73%, the difference was statistically significant (P<O. 05). The incidence of various side effects, which were mild, was less than 10%. There was no statistical difference between the two groups. The percentage of subjects who had their next menstruation 3 days earlier or later than their expected menstruation in LNG group and Mife group was 77. 7% and 78. 5% respectively. Conclusion: Use of levonorgestrel or low dose mifepristone for emergency contraception is effective and safe. 展开更多
关键词 mergency CONTRACEPTION LEVONORGESTREL MIFEPRISTONE RANDOMIZED comparative TRIAL
暂未订购
Practical Challenges in Comparing Chinese and American Local Government
13
作者 Matthew S. Mingus Cheng Li Wang Yan 《International Relations and Diplomacy》 2015年第10期661-680,共20页
Parts of China are an advanced industrial society with excellent public transportation, universities, industry, and other modern features; while other parts (geographically and functionally) remain a developing nati... Parts of China are an advanced industrial society with excellent public transportation, universities, industry, and other modern features; while other parts (geographically and functionally) remain a developing nation. For China, to build a stronger and more equitable society requires much work to develop governance at the local level. In pursuit of this goal, China actively seeks to learn lessons from abroad, including from American local government. This article examines the similarities and differences between these two nations and their systems of government toward the end of identifying potential challenges to Chinese efforts to learn from American-style local governance. This is grounded in policy transfer theory, which guides the discussion of how to learn from other jurisdictions--from other jurisdictions within the nation, from other points in time within the nation, and from other nations. Perhaps the ultimate questions are, "Should China continue efforts to learn from external models or focus its energy internally?" and "Does China need a more clearly defined governance model rather than its current approach that simultaneously allows and questions a high degree of decentralization (both within the party and the government)?" This paper seeks to add to that intellectual discourse by applying recent data and a conceptual framework. 展开更多
关键词 policy transfer Chinese local government comparative institutions
在线阅读 下载PDF
A feasible method for comparing the power dependent photostability of fluorescent proteins 被引量:1
14
作者 刘俊 储军 +4 位作者 朱宏宇 徐玲玲 张智红 曾绍群 黄振立 《Chinese Optics Letters》 SCIE EI CAS CSCD 2008年第12期941-943,共3页
A feasible method of combining the concept of fluorescence half-life and the power dependent photo- bleaching rate for characterizing the practical photostability of fluorescent proteins (FPs) was introduced. Furthe... A feasible method of combining the concept of fluorescence half-life and the power dependent photo- bleaching rate for characterizing the practical photostability of fluorescent proteins (FPs) was introduced. Furthermore, by using a fluorescent photostability standard, a relative comparison of the photostabilty of FPs from different research groups was proposed, which would be of great benefit for developing novel FPs with optimized emission wavelength, better brightness, and improved photostability. We used rho- damine B as an example to verify this method and evaluate the practical photostability of a far-red FP, mKate-S158C. Experimental results indicated good potential of this method for further study. 展开更多
关键词 A feasible method for comparing the power dependent photostability of fluorescent proteins
原文传递
Chromosome-level genome assembly of finger millet(Eleusine coracana)provides insights into drought resistance
15
作者 Jiguang Li Chaonan Guan +8 位作者 Xiaobo Li Yanlan Wang Jiayue He Liqin Hu Yaliang Shi Yuqi He Kaixuan Zhang Rui Tang Meiliang Zhou 《Journal of Genetics and Genomics》 2026年第2期321-331,共11页
Finger millet(Eleusine coracana Gaertn.),a nutritionally rich and drought-resilient C4 cereal,possesses exceptional grain storage longevity(up to 50 years).Here,we report a high-quality genome assembly of the allotetr... Finger millet(Eleusine coracana Gaertn.),a nutritionally rich and drought-resilient C4 cereal,possesses exceptional grain storage longevity(up to 50 years).Here,we report a high-quality genome assembly of the allotetraploid cultivar C142,revealing extensive structural rearrangements between its two subgenomes(subA and subB),which are associated with asymmetric gene expression and subgenome dominance favoring subA.SubB diverged from subA and E.indica approximately 6.8 million years ago.Subsequently,two whole-genome duplication events shaped the current genome architecture,contributing to gene redundancy and adaptive potential.Notably,expansion of stress-related gene families,such as aldo-keto reductases,suggests a role in oxidative stress response and drought adaptation.Using genome-wide association studies,we identify several candidate genes associated with key agronomic traits.Among them,EcMDHAR,encoding monodehydroascorbate reductase,plays a critical role in enhancing drought tolerance.Different EcMDHAR haplotypes exhibit distinct expression profiles,supporting their functional relevance in drought adaptation.This genomic resource not only advances our understanding of polyploid genome evolution in millets,but also provides a foundation for genome-assisted improvement of drought resistance and nutritional quality in finger millet. 展开更多
关键词 Eleusine coracana Comparative genomics Structural variation GWAS Drought resistance
原文传递
Brain structural plasticity in large-brained mammals:Not only narrowing roads
16
作者 Marco Ghibaudi Alessandro Zanone Luca Bonfanti 《Neural Regeneration Research》 2026年第5期1669-1680,共12页
The capacity of the central nervous system for structural plasticity and regeneration is commonly believed to show a decreasing progression from“small and simple”brains to the larger,more complex brains of mammals.H... The capacity of the central nervous system for structural plasticity and regeneration is commonly believed to show a decreasing progression from“small and simple”brains to the larger,more complex brains of mammals.However,recent findings revealed that some forms of neural plasticity can show a reverse trend.Although plasticity is a well-preserved,transversal feature across the animal world,a variety of cell populations and mechanisms seem to have evolved to enable structural modifications to take place in widely different brains,likely as adaptations to selective pressures.Increasing evidence now indicates that a trade-off has occurred between regenerative(mostly stem cell–driven)plasticity and developmental(mostly juvenile)remodeling,with the latter primarily aimed not at brain repair but rather at“sculpting”the neural circuits based on experience.In particular,an evolutionary trade-off has occurred between neurogenic processes intended to support the possibility of recruiting new neurons throughout life and the different ways of obtaining new neurons,and between the different brain locations in which plasticity occurs.This review first briefly surveys the different types of plasticity and the complexity of their possible outcomes and then focuses on recent findings showing that the mammalian brain has a stem cell–independent integration of new neurons into pre-existing(mature)neural circuits.This process is still largely unknown but involves neuronal cells that have been blocked in arrested maturation since their embryonic origin(also termed“immature”or“dormant”neurons).These cells can then restart maturation throughout the animal's lifespan to become functional neurons in brain regions,such as the cerebral cortex and amygdala,that are relevant to high-order cognition and emotions.Unlike stem cell–driven postnatal/adult neurogenesis,which significantly decreases from small-brained,short-living species to large-brained ones,immature neurons are particularly abundant in large-brained,long-living mammals,including humans.The immature neural cell populations hosted in these complex brains are an interesting example of an“enlarged road”in the phylogenetic trend of plastic potential decreases commonly observed in the animal world.The topic of dormant neurons that covary with brain size and gyrencephaly represents a prospective turning point in the field of neuroplasticity,with important translational outcomes.These cells can represent a reservoir of undifferentiated neurons,potentially granting plasticity within the high-order circuits subserving the most sophisticated cognitive skills that are important in the growing brains of young,healthy individuals and are frequently affected by debilitating neurodevelopmental and degenerative disorders. 展开更多
关键词 adult neurogenesis AMYGDALA brain plasticity cerebral cortex comparative approach evolution immature neurons
暂未订购
A comparative study of national electric bicycle standards in China and Malaysia
17
作者 Wei Yilin Qin Lujuan Yang Mengying 《China Standardization》 2026年第2期57-61,共5页
China ranked first worldwide in the production and export of electric bicycles.As an emerging market for electric bicycles,Malaysia holds significant potential for trade collabor ation with China in this sector.This s... China ranked first worldwide in the production and export of electric bicycles.As an emerging market for electric bicycles,Malaysia holds significant potential for trade collabor ation with China in this sector.This study presents a compar ative analysis of the national electric bicycle standards in China and Malaysia,offering technical insights from a standardization perspective.These insights aim to support Chinese enterprises in strategically positioning their technologies in the Malaysian market.The findings reveal significant differences in technical parameters,safety requirements,and testing methods,highlighting the need for tailored product adapt ation. 展开更多
关键词 electric bicycle STANDARDS comparative study
原文传递
Genome of aerial alga Trentepohlia odorata reveals insights into the evolution of terrestrial lifestyle in green algae
18
作者 Yuanhao Li Jiao Fang +8 位作者 Xiaoya Ma Hao Wang Shiyu Zhang Yu Peng Lin Chen Guoxiang Liu Huan Zhu Zhenhua Zhang Bojian Zhong 《Journal of Genetics and Genomics》 2026年第3期433-446,共14页
Trentepohliales is a completely terrestrial order within Ulvophyceae(the core Chlorophyta),and its closely related lineages are mainly marine macroalgae(green seaweeds).Despite the considerable interest in their biote... Trentepohliales is a completely terrestrial order within Ulvophyceae(the core Chlorophyta),and its closely related lineages are mainly marine macroalgae(green seaweeds).Despite the considerable interest in their biotechnological potential,little is known about their adaptations to challenging terrestrial habitats.Here,we assemble the high-quality reference genome of Trentepohlia odorata.This alga shows duplications of key genes associated with lipid metabolism and carotenoid synthesis,potentially facilitating intracellular accumulation of lipid droplets and carotenoids.We further reveal positive selection and expansion of gene families involved in vesicle trafficking and cell division regulation in T.odorata compared with other algae(cleavage furrow-mediated cell division)in Ulvophyceae,providing a genetic foundation for the evolution of phragmoplast-mediated cell division.The combined C_(4)-like and biophysical CO_(2)-concentrating mechanisms(CCMs)of T.odorata enable adaptation to fluctuating CO_(2) environments,and support efficient photosynthesis under CO_(2)-limited conditions.Adaptive strategies of T.odorata to terrestrial stressors,such as drought,intense light,and UV-B radiation,include horizontally acquired genes involved in cell wall synthesis and remodeling,homeostasis of aldehydes,and expanded genes associated with reactive oxygen species(ROS),DNA repair,and photoprotection.Our study provides a valuable genomic resource for studying aerial algae and improves understanding of plant terrestrialization. 展开更多
关键词 Plant terrestrialization Aerial green alga Environmental adaptation Trentepohliales Comparative genomics
原文传递
Comparative evaluation of single-mask and single-shot X-ray phase-contrast and dual-energy computed tomography analyses on soft-tissue phantom
19
作者 Chang Li Xiao-Xuan Ren +6 位作者 Liang-Liang Lv Shu-Yi Sun Jian Zhang Yin-Qi Lei Xiao-Dong Pan Cui Zhang Gong-Ping Li 《Nuclear Science and Techniques》 2026年第5期241-251,共11页
In clinical diagnosis,conventional X-ray absorption-contrast computed tomography(XACT)technology cannot effectively differentiate diseased tissues from the healthy ones.X-ray phase-contrast CT(XPCT)and dual-energy CT(... In clinical diagnosis,conventional X-ray absorption-contrast computed tomography(XACT)technology cannot effectively differentiate diseased tissues from the healthy ones.X-ray phase-contrast CT(XPCT)and dual-energy CT(DECT),emerging X-ray imaging technologies with superior diagnostic capabilities,address this issue through different principles.While both XPCT and DECT have advantages and disadvantages in medical applications,their systematic comparison is lacking.Using GEANT4 and MATLAB,in this study,we established an X-ray phase-contrast imaging(XPCI)model based on single-mask and single-shot edge illumination for fast XPCT imaging,comparing it with DECT on soft-tissue phantom.XACT served as a reference for comparison.The study introduces an evaluation system using statistical measures including absolute error,mean absolute error,structure similarity index measure,peak signal-to-noise ratio,and contrast-to-noise ratio.Results show XPCT images are superior to DECT.The XPCI model can be improved on existing medical CT for widespread medical application. 展开更多
关键词 Comparative evaluation X-ray phase-contrast CT Edge illumination Dual-energy CT GEANT4
在线阅读 下载PDF
Brief application notes for vision transformer (ViT) and convolutional neural network (CNN) in medical imaging
20
作者 Wei Kitt Wong Melinda Melinda 《Medical Data Mining》 2026年第2期34-42,共9页
In contemporary computer vision,convolutional neural networks(CNNs)and vision transformers(ViTs)represent the two primary architectural paradigms for image recognition.While both approaches have been widely adopted in... In contemporary computer vision,convolutional neural networks(CNNs)and vision transformers(ViTs)represent the two primary architectural paradigms for image recognition.While both approaches have been widely adopted in medical imaging applications,they operate based on fundamentally different computational principles.This report attempts to provide brief application notes on ViTs and CNNs,particularly focusing on scenarios that guide the selection of one architecture over the other in practical medical implementations.Generally,CNNs rely on convolutional kernels,localized receptive fields,and weight sharing,enabling efficient hierarchical feature extraction.These properties contribute to strong performance in detecting spatially constrained patterns such as textures,edges,and anatomical boundaries,while maintaining relatively low computational requirements.ViTs,on the other hand,decompose images into smaller segments referred to as tokens and employ self-attention mechanisms to model relationships across the entire image.This global modeling capability allows ViTs to capture long-range dependencies that may be difficult for convolution-based architectures to learn.However,ViTs typically achieve optimal performance when trained on extremely large datasets or when supported by extensive pretraining,as their reduced inductive bias requires greater data exposure to learn robust representations.This report briefly examines the architectural structure,underlying mathematical foundations,and relative performance characteristics of CNNs and ViTs,drawing upon recent findings from contemporary research.Emphasis is placed on understanding how differences in data availability,computational resources,and task requirements influence model effectiveness across medical imaging domains.Most importantly,the report serves as a concise application guide for practitioners seeking informed implementation decisions between these two influential deep learning frameworks. 展开更多
关键词 convolutional neural network vision transformer comparative study medical imaging
在线阅读 下载PDF
上一页 1 2 77 下一页 到第
使用帮助 返回顶部