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Philips推出新型灯泡底座
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《世界专业音响与灯光》 2006年第2期73-73,共1页
在意大利Rimni举行的SIB演出与娱乐展览会上,Philips展出了一种新的灯泡设计概念FastFit以及用这种新设计概念生产出的新型灯泡底座,用于Philips的MSR Gold^TM 700 SA/SE、MSR GOld^TM 1200 SA/SE和Hi-Brite 1200 Watt灯泡。
关键词 PHILIPS 灯泡 底座 设计概念 MSR 展览会 SIB 意大利 SE SA
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Philips IP STB系统解决方案
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《世界电子元器件》 2007年第2期79-79,共1页
STB500是一个完整的、针对互联网协议机顶盒的系统解决方案,提供了所需的全部基本功能,从信号接收到AN输出和用户接口。功能强大的Nexperia媒体处理器是该解决方案的核心,可以轻松开发系统设计和软件测试。
关键词 PHILIPS 系统解 Nexperia媒体处理器 STB IP 互联网协议 用户接口 信号接收
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Philips的集成分立(ID)器件
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《世界电子元器件》 2007年第10期66-68,73,共4页
在线座谈(Online Seminar)是中电网于2000年推出的创新服务,通过"视频演示+专家解说+在线问答"三位一体相结合的形式,充分发挥网络平台的便捷性,实现了先进半导体技术提供商与系统设计工程师的实时互动交流,其形式和内容都广... 在线座谈(Online Seminar)是中电网于2000年推出的创新服务,通过"视频演示+专家解说+在线问答"三位一体相结合的形式,充分发挥网络平台的便捷性,实现了先进半导体技术提供商与系统设计工程师的实时互动交流,其形式和内容都广受电子行业工程师的好评。本刊每期将挑选一些精华内容整理成文,以飨读者。欲了解更多、更详细的内容,敬请登录http://seminar.eccn.com。 展开更多
关键词 分立器件 PHILIPS 成分 电平转换器 电路板面积 有源元件 无源元件 寄生效应
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Drought Tolerance and Recovery of the Sedge Carex planostachys (Cyperaceae) from Central Texas Woodlands
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作者 E. Rob Wayne Oscar William Van Auken 《American Journal of Plant Sciences》 CAS 2024年第9期746-765,共20页
Carex planostachys Kunze (Cyperaceae, Cedar sedge) is an herbaceous species in a genus commonly inhabiting mesic or hydric habitats. Carex planostachys is found in arid and semi-arid Juniperus woodlands. Arid conditio... Carex planostachys Kunze (Cyperaceae, Cedar sedge) is an herbaceous species in a genus commonly inhabiting mesic or hydric habitats. Carex planostachys is found in arid and semi-arid Juniperus woodlands. Arid conditions impose survival challenges to plants in dry areas. Some plants have plasticity responses to soil water content and continued normal though reduced functions through droughts, but most herbaceous plants do not survive. Limited previous studies have suggested C. planostachys is tolerant of drought. Physiological responses of C. planostachys from Juniperus woodlands was examined is this study to determine how long plants could survive without water and if they are capable of recovery from very negative water potentials beyond what is considered the permanent wilting point for most herbaceous plants. Plants were placed in pots in partial shade in this experiment. Water loss from the soil with plants was an inverse 2nd order polynomial function with soil water decreasing from 32% to 8% by day 28 of the study. Leaf water potential was also an inverse 2nd order polynomial function but did not decline significantly until 14 days without watering. Leaf water potential was −10.0 MPa after 35 days without watering. Non-watered plants Anet, (photosynthetic rate) was significantly lower compared to the water treatment by day 21 as was stomatal conductance and transpiration. When non-watered plants were watered after 21, 28 or 35 days, full recovery of physiological responses occurred within 7 days. The length of time that C. planostachys was able to withstand drought was greater than the annual trends in lack of precipitation during springtime in this area. Carex planostachys can photosynthesize at water stress between −8 and −10 MPa. Carex planostachys drought and shade tolerance enables it to occupy an understory niche devoid of other herbaceous plants. 展开更多
关键词 CO2 Uptake Conductance Gas Exchange Photosynthesis Respiration TRANSPIRATION Water Stress Water Potential.
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Investigating the relationship between intracranial atherosclerotic plaque remodelling and diabetes using high-resolution vessel wall imaging
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作者 Yong-Qian Mo Hai-Yu Luo +5 位作者 Han-Wen Zhang Yu-Feng Liu Kan Deng Xiao-Lei Liu Biao Huang Fan Lin 《World Journal of Diabetes》 SCIE 2024年第1期72-80,共9页
BACKGROUND Intracranial atherosclerosis,a leading cause of stroke,involves arterial plaque formation.This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imag... BACKGROUND Intracranial atherosclerosis,a leading cause of stroke,involves arterial plaque formation.This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imaging(HR-VWI).AIM To investigate the factors of intracranial atherosclerotic remodelling patterns and the relationship between intracranial atherosclerotic remodelling and diabetes mellitus using HR-VWI.METHODS Ninety-four patients diagnosed with middle cerebral artery or basilar artery INTRODUCTION Intracranial atherosclerotic disease is one of the main causes of ischaemic stroke in the world,accounting for approx-imately 10%of transient ischaemic attacks and 30%-50%of ischaemic strokes[1].It is the most common factor among Asian people[2].The adaptive changes in the structure and function of blood vessels that can adapt to changes in the internal and external environment are called vascular remodelling,which is a common and important pathological mechanism in atherosclerotic diseases,and the remodelling mode of atherosclerotic plaques is closely related to the occurrence of stroke.Positive remodelling(PR)is an outwards compensatory remodelling where the arterial wall grows outwards in an attempt to maintain a constant lumen diameter.For a long time,it was believed that the degree of stenosis can accurately reflect the risk of ischaemic stroke[3-5].Previous studies have revealed that lesions without significant luminal stenosis can also lead to acute events[6,7],as summarized in a recent meta-analysis study in which approximately 50%of acute/subacute ischaemic events were due to this type of lesion[6].Research[8,9]has pointed out that the PR of plaques is more dangerous and more likely to cause acute ischaemic stroke.Previous studies[10-13]have found that there are specific vascular remodelling phenomena in the coronary and carotid arteries of diabetic patients.However,due to the deep location and small lumen of intracranial arteries and limitations of imaging techniques,the relationship between intracranial arterial remodelling and diabetes is still unclear.In recent years,with the development of magnetic resonance technology and the emergence of high-resolution(HR)vascular wall imaging,a clear and multidimensional display of the intracranial vascular wall has been achieved.Therefore,in this study,HR wall imaging(HR-VWI)was used to display the remodelling characteristics of bilateral middle cerebral arteries and basilar arteries and to explore the factors of intracranial vascular remodelling and its relationship with diabetes. 展开更多
关键词 High-resolution vessel wall imaging Intracranial atherosclerosis Vascular remodelling Magnetic resonance imaging
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Algorithms for Multicriteria Scheduling Problems to Minimize Maximum Late Work, Tardy, and Early
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作者 Karrar Alshaikhli Aws Alshaikhli 《Journal of Applied Mathematics and Physics》 2024年第2期661-682,共22页
This study examines the multicriteria scheduling problem on a single machine to minimize three criteria: the maximum cost function, denoted by maximum late work (V<sub>max</sub>), maximum tardy job, denote... This study examines the multicriteria scheduling problem on a single machine to minimize three criteria: the maximum cost function, denoted by maximum late work (V<sub>max</sub>), maximum tardy job, denoted by (T<sub>max</sub>), and maximum earliness (E<sub>max</sub>). We propose several algorithms based on types of objectives function to be optimized when dealing with simultaneous minimization problems with and without weight and hierarchical minimization problems. The proposed Algorithm (3) is to find the set of efficient solutions for 1//F (V<sub>max</sub>, T<sub>max</sub>, E<sub>max</sub>) and 1//(V<sub>max</sub> + T<sub>max</sub> + E<sub>max</sub>). The Local Search Heuristic Methods (Descent Method (DM), Simulated Annealing (SA), Genetic Algorithm (GA), and the Tree Type Heuristics Method (TTHM) are applied to solve all suggested problems. Finally, the experimental results of Algorithm (3) are compared with the results of the Branch and Bound (BAB) method for optimal and Pareto optimal solutions for smaller instance sizes and compared to the Local Search Heuristic Methods for large instance sizes. These results ensure the efficiency of Algorithm (3) in a reasonable time. 展开更多
关键词 Scheduling Single Machine Hierarchical Simultaneous Minimization ALGORITHMS Branch and Bound Local Search Heuristic Methods
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APT联合mDIXON-Quant成像对前列腺癌和前列腺增生的鉴别诊断价值 被引量:3
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作者 任雪 刘爱连 +5 位作者 陈丽华 宋清伟 王楠 林良杰 王家正 张祎 《放射学实践》 CSCD 北大核心 2023年第1期58-64,共7页
目的:探讨酰胺质子转移加权(APT)成像联合脂肪和R2*定量成像(mDIXON-Quant)对前列腺癌(PCa)与前列腺增生(BPH)的鉴别诊断价值。方法:回顾性分析72例经病理证实的前列腺癌(34例)及前列腺增生(38例)患者的病例资料,均于术前行3.0T MRI扫描... 目的:探讨酰胺质子转移加权(APT)成像联合脂肪和R2*定量成像(mDIXON-Quant)对前列腺癌(PCa)与前列腺增生(BPH)的鉴别诊断价值。方法:回顾性分析72例经病理证实的前列腺癌(34例)及前列腺增生(38例)患者的病例资料,均于术前行3.0T MRI扫描,包括常规T1WI、T2WI抑脂、DWI、APT及mDIXON-Quant序列。由两位观察者分别在APT与DWI的融合图及mDIXON-Quant与DWI的融合图上勾画感兴趣区(ROI),测量得到相应的APT、FF、R2*和T2*值。通过组内相关系数(ICC)评估观察者间测量的一致性。采用受试者工作特征(ROC)曲线评价APT及mDIXON-Quant各参数的阈值及诊断效能,采用逻辑回归分析将两个序列参数进行联合并评估其诊断效能。采用Delong检验比较ROC曲线下面积(AUC)的差异,采用Spearman检验两个序列有统计学差异参数的相关性。结果:2位观察者测得两组参数的一致性良好(ICC均>0.75);PCa组的APT值、FF值、R2*值分别为3.033%(2.392,3.808)、2.633%(1.918,3.550)、19.158s-1(15.357,25.375),BPH组的APT值、FF值、R2*值分别为1.767%(1.258,2.208)、1.067%(0.800,1.500)、16.783s-1(15.300,18.175),PCa组明显高于BPH组,差异均有统计学意义(P值均<0.05);PCa组的T2*值为57.017 ms(44.933,67.018),BPH组为61.517 ms(58.483,68.354),PCa组明显低于BPH组,差异有统计学意义(P<0.01)。ROC曲线分析结果显示,APT、FF、R2*、T2*值鉴别诊断PCa与BPH的效能分别为0.805、0.870、0.656、0.655,FF值的鉴别诊断效能显著高于R2*值(P=0.002)和T2*值(P=0.002)。APT联合mDIXON-Quant序列鉴别诊断PCa与BPH的效能为0.913,显著高于APT(P=0.041)和mDIXON-Quant(P=0.032)。相关性分析结果显示APT值与FF值、FF值与R2*值之间存在低度正相关,FF值与T2*值之间存在低度负相关,R2*值与T2*值之间存在高度负相关。结论:APT及mDIXON-Quant两种序列均可有效鉴别PCa与BPH,其中FF值的诊断效能最高,两种技术联合能大幅提升鉴别诊断效能。 展开更多
关键词 前列腺肿瘤 前列腺增生 磁共振成像 酰胺质子转移加权成像
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Quantitative parameters in novel spectral computed tomography:Assessment of Ki-67 expression in patients with gastric adenocarcinoma 被引量:3
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作者 Li-Ting Mao Wei-Cui Chen +6 位作者 Jian-Ye Lu Han-Liang Zhang Yong-Song Ye Yu Zhang Bo Liu Wei-Wei Deng Xian Liu 《World Journal of Gastroenterology》 SCIE CAS 2023年第10期1602-1613,共12页
BACKGROUND The level of Ki-67 expression has served as a prognostic factor in gastric cancer.The quantitative parameters based on the novel dual-layer spectral detector computed tomography(DLSDCT)in discriminating the... BACKGROUND The level of Ki-67 expression has served as a prognostic factor in gastric cancer.The quantitative parameters based on the novel dual-layer spectral detector computed tomography(DLSDCT)in discriminating the Ki-67 expression status are unclear.AIM To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma(GC).METHODS Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma.Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt(kev),the slope of the spectral curve(λ_(HU)),iodine concentration(IC),normalized IC(nIC),effective atomic number(Z^(eff))and normalized Z^(eff)(nZ^(eff))in the arterial phase(AP)and venous phase(VP)were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma.Spearman’s correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status.Receiver operating characteristic(ROC)curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups.RESULTS Thirty-seven and 71 patients were classified as having low and high Ki-67 expression,respectively.CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),and Z^(eff)-related parameters were significantly higher,but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status,and other analyzed parameters showed no statistical difference between the two groups.Spearman’s correlation analysis showed that CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),Z^(eff),and n Z^(eff) exhibited a negative correlation with Ki-67 status,whereas IC and nIC had positive correlation with Ki-67 status.The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status[area under the curve(AUC)=0.967;sensitivity 95.77%;specificity 91.89%)].Nevertheless,the differentiating capabilities of singlevariable model were moderate(AUC value 0.630-0.835).In addition,the nZ_(VP)^(eff) and nIC_(VP)(AUC 0.835 and 0.805)showed better performance than CT_(40 kev-VP),CT_(70 kev-VP) and CT_(100 kev-VP)(AUC 0.630,0.631 and 0.662)in discriminating the Ki-67 status.CONCLUSION Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma.Z^(eff) and IC may be useful parameters for evaluating the Ki-67 expression. 展开更多
关键词 Spectral computer tomography Quantitative parameters Gastric carcinoma Iodine concentration Effective atomic number Ki-67 expression
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Relationship of Microvascular Obstruction with Global and Regional Myocardial Function Determined by Cardiac Magnetic Resonance after ST-Segment Elevation Myocardial Infarction 被引量:1
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作者 Ya-Nan Zhao Jia-Ning Cui +4 位作者 Xing-Hua Zhang Jin-Feng Li Shi-Min Chen Xiu-Zheng Yue Tao Li 《Chinese Medical Sciences Journal》 CAS CSCD 2023年第1期11-19,共9页
Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(S... Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(STEMI)patients after percutaneous coronary intervention.Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1-7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study.Based on the presence or absence of MVO on late gadolinium enhancement images,patients were divided into groups with MVO and without MVO.The infarct zone,adjacent zone,and remote zone were determined based on a myocardial 16-segment model.The radial strain(RS),circumferential strain(CS),and longitudinal strain(LS)of the global left ventricle(LV)and the infarct,adjacent,and remote zones were measured by CMRFT from cine images and compared between patients with and without MVO using independent-samples t-test.Logistic regression analysis was used to assess the association of MVO with the impaired LV function.Results A total of 157 STEMI patients(mean age 56.66±11.38 years)were enrolled.MVO was detected in 37.58%(59/157)of STEMI patients,and the mean size of MVO was 3.00±3.76 mL.Compared with patients without MVO(n=98),the MVO group had significantly reduced LV global RS(t=-4.30,P<0.001),global CS(t=4.99,P<0.001),and global LS(t=3.51,P=0.001).The RS and CS of the infarct zone in patients with MVO were significantly reduced(t=-3.38,P=0.001;t=2.64,P=0.01;respectively)and the infarct size was significantly larger(t=8.37,P<0.001)than that of patients without MVO.The presence of LV MVO[OR=4.10,95%CI:2.05-8.19,P<0.001]and its size[OR=1.38,95%CI:1.10-1.72,P=0.01],along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis,while only heart rate(OR=1.08,95%CI:1.03-1.13,P=0.001)and LV infarct size(OR=1.10,95%CI:1.03-1.16,P=0.003)were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.Conclusion The infarct size was larger in STEMI patients with MVO,and MVO deteriorates the global and regional LV myocardial function. 展开更多
关键词 cardiac magnetic resonance feature tracking ST-segment elevation myocardial infarction microvascular obstruction myocardial strain Myocardial function
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Optimized Three-Dimensional Cardiovascular Magnetic Resonance Whole Heart Imaging Utilizing Non-Selective Excitation and Compressed Sensing in Children and Adults with Congenital Heart Disease
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作者 Ingo Paetsch Roman Gebauer +7 位作者 Christian Paech Frank-Thomas Riede Sabrina Oebel Andreas Bollmann Christian Stehning Jouke Smink Ingo Daehnert Cosima Jahnke 《Congenital Heart Disease》 SCIE 2023年第3期279-294,共16页
Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicabil... Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicability of an advanced cardiovascular magnetic resonance(CMR)whole heart imaging approach utilizing nonselective excitation and compressed sensing for anatomical assessment and interventional guidance of CHD patients in comparison to conventional dynamic CMR angiography.Methods:86 consecutive pediatric patients and adults with congenital heart disease(age,1 to 74 years;mean,35 years)underwent CMR imaging including a freebreathing,ECG-triggered 3D nonselective SSFP whole heart acquisition using compressed SENSE(nsWHcs).Anatomical assessability and signal intensity ratio(SIR)measurements were compared with conventional dynamic 3D-/4D-MR angiography.Results:The most frequent diagnoses were partial anomalous pulmonary venous drainage(17/86,20%),transposition of the great arteries(15/86,17%),tetralogy of Fallot(12/86,14%),and a single ventricle(7/86,8%).Image quality of nsWHcs was rated as excellent/good in 98%of patients.nsWHcs resulted in a reliable depiction of all large thoracic vessels(anatomic assessability,99%–100%)and the proximal segments of coronary arteries and coronary sinus(>90%).nsWHcs achieved a homogenously distributed SIR in all cardiac cavities and thoracic vessels without a significant difference between pulmonary and systemic circulation(10.9±3.5 and 10.6±3.4;p=0.15),while 3D angiography showed significantly increased SIR for targeted vs.non-targeted circulation(PA-angiography,15.2±8.1 vs.5.8±3.6,p<0.001;PV-angiography,7.0±3.9 vs.17.3±6.8,p<0.001).Conclusions:The proposed nsWHcs imaging approach provided a consistently high image quality and a homogeneous signal intensity distribution within the pulmonary and systemic circulation in pediatric patients and adults with a wide spectrum of congenital heart diseases.nsWHcs enabled detailed anatomical assessment and three-dimensional reconstruction of all cardiac cavities and large thoracic vessels and can be regarded particularly useful for preprocedural planning and interventional guidance in CHD patients. 展开更多
关键词 Cardiovascular magnetic resonance imaging congenital heart disease whole heart imaging nonselective SSFP compressed SENSE MR angiography
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Bioengineered materials with selective antimicrobial toxicity in biomedicine 被引量:1
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作者 Pooyan Makvandi Hao Song +8 位作者 Cynthia K.Y.Yiu Rossella Sartorius Ehsan Nazarzadeh Zare Navid Rabiee Wei-Xi Wu Ana Cláudia Paiva-Santos Xiang-Dong Wang Cheng-Zhong Yu Franklin R.Tay 《Military Medical Research》 SCIE CAS CSCD 2023年第6期798-817,共20页
Fungi and bacteria afflict humans with innumerous pathogen-related infections and ailments.Most of the commonly employed microbicidal agents target commensal and pathogenic microorganisms without discrimination.To dis... Fungi and bacteria afflict humans with innumerous pathogen-related infections and ailments.Most of the commonly employed microbicidal agents target commensal and pathogenic microorganisms without discrimination.To distinguish and fight the pathogenic species out of the microflora,novel antimicrobials have been developed that selectively target specific bacteria and fungi.The cell wall features and antimicrobial mechanisms that these microorganisms involved in are highlighted in the present review.This is followed by reviewing the design of antimicrobials that selectively combat a specific community of microbes including Gram-positive and Gram-negative bacterial strains as well as fungi.Finally,recent advances in the antimicrobial immunomodulation strategy that enables treating microorganism infections with high specificity are reviewed.These basic tenets will enable the avid reader to design novel approaches and compounds for antibacterial and antifungal applications. 展开更多
关键词 Antimicrobial nanotechnology Immumodualtion Selective toxicity Smart nanomaterials Targeting microorganism
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MR弥散加权成像在延迟期强化的肝脏恶性肿瘤与肝血管瘤鉴别诊断中的应用 被引量:10
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作者 白若冰 郭启勇 +3 位作者 石喻 卢再鸣 杨京川 孙宝海 《中国临床医学影像杂志》 CAS 北大核心 2011年第5期316-320,共5页
目的:探讨MR弥散加权成像(DWI)在延迟期明显强化的肝脏恶性肿瘤和肝血管瘤鉴别诊断中的应用价值。方法:本研究收集2009年7月~2010年1月在我院就诊的肝脏占位性病变,且病变延迟期强化的病例共32例。其中包括肝细胞癌9例,胆管细胞癌12... 目的:探讨MR弥散加权成像(DWI)在延迟期明显强化的肝脏恶性肿瘤和肝血管瘤鉴别诊断中的应用价值。方法:本研究收集2009年7月~2010年1月在我院就诊的肝脏占位性病变,且病变延迟期强化的病例共32例。其中包括肝细胞癌9例,胆管细胞癌12例,肝血管瘤11例。延迟期强化病灶定义为肝脏多期动态增强扫描显示病灶延迟期强化程度高于动脉期。如果病灶较大且血供明显不均匀,则按照上述条件将同一病灶内的延迟强化区纳入研究范围。对所有病灶进行b=500s/mm2的DWI扫描,DWI扫描所得图像由两名高年资放射科医师(执业年龄大于5年)背靠背评价,主要评价在b=500s/mm2图像上肝脏占位性病变信号的高低。利用后处理得到的表观弥散系数(ADC)图划定感兴趣区进行ADC值测量。采用SPSS16.0软件包对图像分析及处理所得到的计量及计数数据进行处理。对不同肝脏占位性病变b=500s/mm2时的图像信号高低的评价结果进行χ2检验,以P〈0.05作为有显著性差异。所有病灶的ADC值用均数±标准差表示,肝细胞癌、胆管细胞癌及肝血管瘤病例的ADC值之间两两进行均数比较t检验进行分析,以P〈0.05为具有统计学意义。结果:本实验所研究的这3种肝脏占位性病变当b=500s/mm2图像信号高低没有显著性差异(χ2=1.30,P〉0.05)。肝细胞癌病例ADC值[(1.28±0.46)mm2/s]和胆管细胞癌病例ADC值[(1.61±0.38)mm2/s]均显著低于肝血管瘤患者[(2.85±0.89)mm2/s](t=4.780,P=0.000;t=3.7025,P=0.001)。而肝细胞癌病例与胆管细胞癌病例的ADC值没有显著性差异(t=1.8008,P=0.088)。结论:MR DWI在延迟期强化肝脏恶性肿瘤与肝血管瘤鉴别诊断中有较高的应用价值,可以作为常规序列的有益补充。 展开更多
关键词 肝肿瘤 血管瘤 磁共振成像 诊断 鉴别
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不锈钢的X射线荧光光谱分析 被引量:17
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作者 郝贡章 卜赛斌 +1 位作者 高新华 谢荣厚 《分析测试学报》 CAS CSCD 北大核心 2001年第2期66-69,共4页
用高性能飞利浦PW2400X射线荧光光谱仪 ,测定不锈钢中Al、Si、P、S、Ti、Cr、Mn、Co、Ni、Cu、As、Mo、Sn、W、Fe15个元素。给出了各元素的干扰校正系数和基体效应校正系数。方法准确、灵敏、稳定性好、速度快。
关键词 X射线荧光光谱 不锈钢 元素分析
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烟草转化株烟碱含量对其向降烟碱转化程度的影响 被引量:10
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作者 史宏志 L.P.Bush +1 位作者 王瑞华 M.Krauss 《中国烟草学报》 EI CAS CSCD 2004年第5期28-33,共6页
在烟株生长早期鉴别转化株,需要对转化株的烟碱转化进行诱导以使转化性状充分表达,但同一基因型材料在不同生长条件 下经诱导产生的烟碱转化程度存在较大差异。本试验旨在探讨转化株的烟碱基础含量对诱导后烟碱转化程度的影响。结果表明... 在烟株生长早期鉴别转化株,需要对转化株的烟碱转化进行诱导以使转化性状充分表达,但同一基因型材料在不同生长条件 下经诱导产生的烟碱转化程度存在较大差异。本试验旨在探讨转化株的烟碱基础含量对诱导后烟碱转化程度的影响。结果表明由 于打顶和增施氮肥造成烟碱基础含量增高可显著降低诱导后的烟碱转化程度。在温室条件下,通过调节氮肥施用量获得具有不同 烟碱含量的植株,以白肋烟TN90的高转化品系为材料的试验表明,当烟碱基础含量超过2.0%时,烟碱向降烟碱转化不完全,随着 烟碱含量的增高,烟碱转化百分率几乎呈线形下降。采用由高转化系和非转化系杂交的F1植株为材料进行试验,发现烟碱转化百 分率随烟碱含量下降的趋势更加明显。采用低转化株的自交分离后代进行试验,发现在低施氮水平下对转化株进行诱导和鉴别的 有效性高于在高施氮条件下对转化株的诱导和鉴别。因此,使烟株维持较低的烟碱水平有利于转化株特别是低转化株的有效鉴别。 展开更多
关键词 烟草 烟碱 降烟碱 转化 转化株 去甲基
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光点与会聚测试系统的设备需求与配置 被引量:3
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作者 杨晓伟 李晓华 +2 位作者 陈福朝 王琦龙 Gerardvan Veldhoven 《真空科学与技术》 CSCD 北大核心 2003年第1期53-56,共4页
光点测试和会聚测试是验证CPT电子枪偏转线圈性能的重要手段之一。本文提出基于合理的测试方法、有效适当的测试设备 ,建立最佳的测试系统。针对光点测试和会聚测试系统中的各种设备 ,介绍它们的应用原理及应用效果 。
关键词 CPT电子枪 偏转线圈 性能 光点测试 会聚测试 设备 测试系统
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采样定理、视觉原理及无监督聚类分析理论 被引量:3
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作者 沈红斌 杨杰 +1 位作者 王士同 陈宁江 《上海交通大学学报》 EI CAS CSCD 北大核心 2005年第4期544-548,共5页
通过引入采样定理,提出了基于视觉采样定理的新聚类算法,将生物物理学中的Weber定律、采样定理和视觉结构有效地结合起来,并在此算法的基础上提出了聚类的有效性准则.该算法基于视觉系统工作原理,具有更强的物理解释性能.实验表明,此算... 通过引入采样定理,提出了基于视觉采样定理的新聚类算法,将生物物理学中的Weber定律、采样定理和视觉结构有效地结合起来,并在此算法的基础上提出了聚类的有效性准则.该算法基于视觉系统工作原理,具有更强的物理解释性能.实验表明,此算法简洁、有效. 展开更多
关键词 聚类算法 视觉系统 采样定理 吸引子
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烟碱向降烟碱转化对烟叶麦斯明和TSNA含量的影响 被引量:55
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作者 史宏志 Bush L P Krauss M 《烟草科技》 EI CAS 2004年第10期27-30,共4页
以白肋烟TN90为材料,研究了非转化株、低转化株及高转化株烟叶样品的烟碱转化程度及降烟碱含量与烟叶麦斯明和烟草特有亚硝胺(TSNA)含量的关系。结果表明,随着烟株烟碱转化能力的提高和烟叶降烟碱含量的增加,叶片和主脉的麦斯明含量呈... 以白肋烟TN90为材料,研究了非转化株、低转化株及高转化株烟叶样品的烟碱转化程度及降烟碱含量与烟叶麦斯明和烟草特有亚硝胺(TSNA)含量的关系。结果表明,随着烟株烟碱转化能力的提高和烟叶降烟碱含量的增加,叶片和主脉的麦斯明含量呈线性增加。当烟碱转化率超过20%时,麦斯明含量超过了假木贼碱的含量。在4种主要的TSNA中,具有不同烟碱转化能力的样品间4-(甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)、N-亚硝基新烟草碱(NAT)和N-亚硝基假木贼碱(NAB)含量没有显著差异,N-亚硝基降烟碱(NNN)含量则随着烟碱转化能力的提高和降烟碱含量的增加而大幅度升高,尤其在主脉中表现更为明显。NNN占总TSNA的比例随烟碱转化程度的提高而增加,在高转化烟株中可高达90%,其它3种TSNA占总TSNA的比例相应降低。叶片中NAT含量和比例一般高于NNK,而在主脉中NNK含量高于NAT。 展开更多
关键词 烟草 生物碱 烟碱 降烟碱 转化 转化株 麦斯明 烟草特有亚硝胺 亚硝基降烟碱
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右胸导联V_(4R)和V_(5R)对由右冠脉近段阻塞引起的急性ST段抬高型心肌梗死的诊断价值 被引量:5
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作者 刘霞 Sophia Zhou +2 位作者 邱慷 郭芳 沈卫峰 《临床心电学杂志》 2006年第3期172-174,共3页
目的与右冠脉阻塞关联的ST段抬高型右室心肌梗死,住院期死亡率高。本研究假设是:右胸导联(V4R和V5R导联)有助于发现ST段抬高型右室心肌梗死。1342例患者记录12导联加右胸导联心电图。结果右冠脉近段阻塞者,V4R和V5R导联常见有ST段抬高,... 目的与右冠脉阻塞关联的ST段抬高型右室心肌梗死,住院期死亡率高。本研究假设是:右胸导联(V4R和V5R导联)有助于发现ST段抬高型右室心肌梗死。1342例患者记录12导联加右胸导联心电图。结果右冠脉近段阻塞者,V4R和V5R导联常见有ST段抬高,同时伴有Ⅰ,aVL,V5和V6导联ST段压低;常规12导联心电图通常不能发现ST段抬高。结论对于急性冠脉综合征,提高对ST段抬高型心肌梗死诊断的敏感性,常规12导联附加右胸导联是一项简便的方法。 展开更多
关键词 右胸导联 右冠脉阻塞 ST段抬高 心肌梗死
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粘结桥中使用非刚性连接体修复2个缺失后牙 被引量:3
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作者 谭京 姜慧 +1 位作者 王新知 Michael G.Botelho 《北京大学学报(医学版)》 CAS CSCD 北大核心 2010年第5期575-577,共3页
目的:探讨在粘结桥中加入非刚性连接体用来修复2个缺失后牙。方法:在临床上选择缺失2个后牙且对颌为真牙的病例。共20例,男性9例,女性11例,平均年龄45.6岁,上颌12例,下颌8例。修复体中双尖牙的固位体与栓体连接,栓道与桥体连接,通过栓... 目的:探讨在粘结桥中加入非刚性连接体用来修复2个缺失后牙。方法:在临床上选择缺失2个后牙且对颌为真牙的病例。共20例,男性9例,女性11例,平均年龄45.6岁,上颌12例,下颌8例。修复体中双尖牙的固位体与栓体连接,栓道与桥体连接,通过栓体与栓道将两部分连接在一起。修复体试戴后使用树脂粘接剂PANAVIAF粘结。结果:20例修复体平均使用时间为28.8个月,最长使用时间为42个月。20例病例中只有1例远中固位体发生脱落。经过表面处理后重新粘接,使用良好。所有基牙没有发现有继发龋和牙龈炎。结论:使用非刚性连接体,允许修复体在受到载荷时产生一定的自由动度,降低了金属固位体与树脂粘接面的应力,从而减少了脱粘接的发生。此种方法扩大了粘接桥的适应证,可以取得较好的临床治疗效果。 展开更多
关键词 非刚性连接体 牙应力分析 牙修复体
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扩张型心肌病的心电图改变 被引量:9
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作者 刘霞 Zhou SH +2 位作者 邱慷 朱旭峰 徐少波 《临床心电学杂志》 2005年第4期256-258,共3页
目的观察扩张型心肌病病例的心电图改变。方法26例经心脏超声检查诊断为扩张型心肌病的病例列入观察。分析结果显示所有病例心电图均有异常改变,其中以一度房室阻滞最为常见(35%),其次是ST段下移(31%)和心房颤动(26%)。对心电图各波段测... 目的观察扩张型心肌病病例的心电图改变。方法26例经心脏超声检查诊断为扩张型心肌病的病例列入观察。分析结果显示所有病例心电图均有异常改变,其中以一度房室阻滞最为常见(35%),其次是ST段下移(31%)和心房颤动(26%)。对心电图各波段测定,显示QRS时限延长明显(115±34.5ms),与心脏超声检查测定的左室大小呈线性正相关。结论提示对于心电图出现QRS时限延长,或一度房室阻滞或ST段下移或心房颤动者,有必要进行心脏超声检查。 展开更多
关键词 扩张型心肌病 心电图
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