期刊文献+
共找到95篇文章
< 1 2 5 >
每页显示 20 50 100
Assessing Dual Approaches for Ranking Score Computation via Transitive Triads
1
作者 Bowen Liu 《Journal of Applied Mathematics and Physics》 2024年第11期4020-4029,共10页
The possibility of developing a complete graph invariant computable in polynomial time remains an open question. Consequently, creating efficient algorithms to verify non-isomorphism, including heuristic approaches, i... The possibility of developing a complete graph invariant computable in polynomial time remains an open question. Consequently, creating efficient algorithms to verify non-isomorphism, including heuristic approaches, is essential. Effective implementation of these heuristics necessitates both the adaptation of existing graph invariants and the invention of novel ones, which continues to be a relevant challenge. Numerous current invariants are capable of distinguishing a significant number of graphs rapidly in real-time scenarios. In this study, we present an invariant tailored for tournaments, a specific class of directed graphs. Tournaments are particularly intriguing because the count of distinct tournaments for a given number of vertices aligns with that of undirected graphs of the same size. The introduced invariant evaluates all possible tournament subsets derived from the original digraph that share the identical arc set. For each subset tournament, standard rankings are computed and aggregated to produce the final vertex scores, which serve as the new invariant. Our analysis indicates that this newly proposed invariant diverges from the most straightforward tournament invariant, which typically assigns scores to each participant. Preliminary computational tests demonstrate that the minimal correlation between the sequences generated by these two invariants occurs at a vertex count of 15. 展开更多
关键词 Graph Invariant Directed Graphs Tournament Theory Transitive triads
下载PDF
Prenatal ultrasonic characteristics and diagnosis of fetal Currarino syndrome:Report of 2 cases and review of literature
2
作者 WEI Yingni ZHANG Yuchen +3 位作者 DENG Zongfeng WANG Yingqiu HUANG Qiaojie CHEN Yayan 《中国医学影像技术》 CSCD 北大核心 2024年第8期1212-1215,共4页
Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyz... Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyzed,while 6 CS fetuses with complete prenatal ultrasonic data in literature were reviewed.Prenatal ultrasonic characteristics of CS fetuses and the method for prenatal diagnosis of CS were discussed.Results Among 8 CS fetuses diagnosed with prenatal ultrasound,4 were female singletons with a clear family history of CS,and MNX 1 gene mutation was found in 1 fetus.The other 4 fetuses were 2 pairs of male monochorionic twins,all with MNX 1 gene mutation.Among 8 CS fetuses,complete triad(sacral agenesis abnormalities,anorectal malformation and presacral mass)were displayed only in 2 fetuses,while all 8 had sacral agenesis abnormalities and 6(6/8,75.00%)were detected with prenatal ultrasound,6 had low location of conus medullaris and 2(2/6,33.33%)detected with prenatal ultrasound.Conclusion Prenatal ultrasound was the first choice for non-invasive diagnosis of fetal CS.When one of sacral agenesis abnormalities,anorectal malformation and presacral mass was found with prenatal ultrasound,the possibility of CS should be considered,and fetal MRI,genetic examination and prenatal genetic counselling should be recommended if necessary. 展开更多
关键词 Currarino triad ultrasonography prenatal AMNIOCENTESIS GENES
下载PDF
Rare Case of Large Anterior Meningocele Associated with Uterine Didelphys
3
作者 Joseph Maalouly Matt Wilson +2 位作者 Sanjay Adusumilli Vijidha Rajkumar Shanu Gambhir 《Open Journal of Modern Neurosurgery》 2024年第2期104-107,共4页
We report a 27-year-old female who presented with abdominal distension, saddle anesthesia, and lower back pain. CT and MRI of the abdomen/spine were performed which showed a large anterior sacral meningocele occupying... We report a 27-year-old female who presented with abdominal distension, saddle anesthesia, and lower back pain. CT and MRI of the abdomen/spine were performed which showed a large anterior sacral meningocele occupying most of the pelvic and abdominal cavity and displacement of their respective contents. Anterior approach was chosen, uterine didelphys was identified and mobilized, meningocele identified and gentle drainage with subsequent resection of the cyst wall and watertight closure was achieved. Subsequent MRI demonstrated resolution of most the sacral meningocele. Patient symptoms improved and are doing well. 展开更多
关键词 Sacral Agenesis Curarino Triad Large Meningocele
下载PDF
EGFR Mutation and FHIT Methylation: Inverse Relationship in Patients with Lung Adenocarcinoma and Tuberculosis
4
作者 Mireguli Abudureheman Xiuyou Yan Baidurula Ainitu 《Proceedings of Anticancer Research》 2024年第2期65-72,共8页
Objective:To investigate the genetic correlations between epithelial growth factor receptor(EGFR)mutation and FHIT methylation in patients diagnosed with lung adenocarcinoma(AC)and pulmonary tuberculosis(TB).Methods:T... Objective:To investigate the genetic correlations between epithelial growth factor receptor(EGFR)mutation and FHIT methylation in patients diagnosed with lung adenocarcinoma(AC)and pulmonary tuberculosis(TB).Methods:The presence of EGFR mutations and the methylation status of the FHIT gene in patients presenting with AC and TB were analyzed.The correlation between TB status and the observed genetic and epigenetic variations was also examined.Results:Among the 90 patients included in the study,38 exhibited EGFR mutations(14 among those with TB and 24 among those without TB),while 29 exhibited FHIT myelination(19 among those with TB and 10 among those without TB).Furthermore,the protein expression levels of EGFR and FHIT were significantly higher in patients diagnosed solely with AC compared to those presenting with both AC and TB.A robust inverse correlation was identified between TB status and the frequency of EGFR mutation(P<0.001).Moreover,significant associations were observed between TB status and FHIT methylation(P<0.01).Conclusion:The findings suggest a correlation between TB and the prevalence of EGFR mutation and FHIT methylation in the pathogenesis of AC. 展开更多
关键词 Lung cancer Adenocarcinoma(AC) Tuberculosis(TB) Epithelial growth factor receptor(EGFR) Fragile histidine triad(FHIT)
下载PDF
The Worlds on the Other Side of the Big Bang
5
作者 Avas Khugaev Eugeniya Bibaeva 《Journal of Applied Mathematics and Physics》 2023年第1期276-302,共27页
Taking the Big Bang as an established fact, the question inevitably arises about what exactly caused it, in what environment could it have happened and what happened before it. The developed approach allows us to shed... Taking the Big Bang as an established fact, the question inevitably arises about what exactly caused it, in what environment could it have happened and what happened before it. The developed approach allows us to shed light on many raised questions and to establish what universal laws and structures formed what happened before the Big Bang, to understand its cause and the dynamic processes that led to it. This required a radical revision of many views, giving them a new meaning and content. This approach has led to a consistent and conceptually new understanding of these phenomena, which allowed correctly formulate questions to which there are still no clear answers. Based on this formulation of the problem, we came to new ideas about the nature of Dark energy, Dark matter and the region of their birth, formulated and described the mechanism of the formation of worlds and their hierarchy on the other side of the Big Bang and the mechanism of this explosion itself. The Primary Parent Particle was introduced into the concept, which was the basis of everything and is the carrier of the fundamental Primary space introduced by us, which had at least two phase states. This particle consists of Beginnings united in the form of Borromeo rings. This made it possible to calculate the structure and primary spectrum of elementary particles that arose on the other side of the Big Bang, the mechanisms of their formation and the resulting fundamental interactions that lead to the existence of vortices before the Big Bang;the mechanisms of the birth of multiple universes and much more are also considered. The concept of the “cosmic genetic code" is introduced, the characteristics and mechanism of its formation before the Big Bang are presented. 展开更多
关键词 “Dirac Sea” Big Bang Primary space Primary Parent Particle “swaddled triads MATERIALITY WORLDS DNA of “seeds of Creation” Borromeo rings “clumps” of Dark energy
下载PDF
Clinical anatomy of hepatic vessels by computed tomography angiography:A minireview 被引量:3
6
作者 Aysegul Firat Tugce Taskindere Abbasoglu +1 位作者 Musturay Karcaaltincaba Yasemin H Balaban 《World Journal of Radiology》 2023年第1期1-9,共9页
The liver has a complex vascular anatomy with a unique dual blood supply.Clinical conditions of the liver vary widely and include disorders originating in the vascular and biliary systems as well as the parenchyma.In ... The liver has a complex vascular anatomy with a unique dual blood supply.Clinical conditions of the liver vary widely and include disorders originating in the vascular and biliary systems as well as the parenchyma.In most vascular disorders,the effects on the liver are generally subclinical because of its abundant blood supply.However,early diagnosis of such vascular diseases can significantly reduce patient morbidity and mortality.Because imaging findings of vascular disease are not always readily apparent,diagnosis can be difficult.Computed tomography angiography is an excellent imaging modality for visualizing the vascular anatomy of patients for treatment planning.In this review article,we focus on the vascular anatomy of the liver and the imaging findings in some acute hepatic vascular diseases. 展开更多
关键词 Computed tomography angiography Hepatic artery Portal vein SINUSOID Portal triad Periportal region
下载PDF
Effects of Big Five, HEXACO, and Dark Triad on Counterproductive Work Behaviors: A Meta-Analysis
7
作者 Yating Miao Jigan Wang +1 位作者 Rundian Shen Dongsheng Wang 《International Journal of Mental Health Promotion》 2023年第3期357-374,共18页
Purpose:This study investigates the effects of Big Five,HEXACO,and Dark Triad personality traits on counter-productive work behaviors(CWBs),and examines the moderating effects of countries where the studies were car-r... Purpose:This study investigates the effects of Big Five,HEXACO,and Dark Triad personality traits on counter-productive work behaviors(CWBs),and examines the moderating effects of countries where the studies were car-ried out,gender rate of samples,and scales used to measure personalities.Method:Following the rules of Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA),we include 74 empirical studies published between 2007 and September 2022 with 83 samples and 394 correlations.Studies are selected from both English databases such as Web of Science and Chinese databases such as CNKI.The meta-analysis and meta-regression analysis were both performed using the Comprehensive Meta-Analysis(CMA)program,version 3.7.Results:Although emotionality is irrelevant to CWBs,other Big Five,HEXACO,and Dark Triad personality factors are all significant predictors of CWBs.The effect of Dark Triad(ρ=0.412)is stronger than that of Big Five(ρ=−0.176)and HEXACO(ρ=−0.221).Gender negatively moderates the positive relationship between Dark Triad traits(total and subdimensions)and CWBs.The moderating effects of countries and scales are only signif-icant for very few personalities.Conclusion:Personality traits are important antecedents of CWBs,and gender ratio plays a role as moderator for some personality traits.We propose that organizations should pay more atten-tion to the mental health of employees and future studies could investigate other types of characteristics and moderators. 展开更多
关键词 Personality traits CWBs Big Five HEXACO Dark Triad
下载PDF
Homozygous Hemoglobinosis CC: A Series of 3 Cases and a Review of the Literature
8
作者 Sokhna Aïssatou Touré Moussa Seck +7 位作者 Mohamed Keita Alioune Badara Diallo Elimane Seydi Bousso Fatma Dieng Serigne Mourtalla Gueye Nata Dieng Blaise Felix Faye Saliou Diop 《Open Journal of Blood Diseases》 CAS 2023年第1期11-15,共5页
Hemoglobinosis C occurs mainly in Africa and America with a high frequency in West Africa. In Senegal, homozygous hemoglobinopathy CC constitutes a very rare profile of which only 3 cases are followed in the clinical ... Hemoglobinosis C occurs mainly in Africa and America with a high frequency in West Africa. In Senegal, homozygous hemoglobinopathy CC constitutes a very rare profile of which only 3 cases are followed in the clinical hematology department of Dakar. The 1<sup>st</sup> case is a 49-year-old female patient, with notion of 1<sup>st</sup> degree consanguinity, and a long history of abdominal pain who presented a poorly tolerated anemic syndrome and splenomegaly. The biological assessment showed moderate anemia (7.6 g/dL) with microcytic hypochromia and a CC profile (HbC = 99.2%;HbA2 = 0.8%) on hemoglobin electrophoresis. The second case was a 22-year-old female patient with a notion of 2<sup>nd</sup> degree consanguinity who presented a Chauffard triad. The haemogram showed mild anaemia (11 g/dL), microcytic and hypochromic. Hemoglobin electrophoresis confirmed a CC profile (HbC = 95.3%;HbA2 = 4.7%). The third patient was 27 years old, with a history of diffuse abdominal pain and 2<sup>nd</sup> degree consanguinity. The haemogram and haemoglobin electrophoresis confirmed the CC profile (HbC = 94.6%;HbA2 = 5.4%). The negativity of the Emmel test in front of this presentation suggestive of sickle cell disease means that this type of hemoglobinopathy is diagnosed late in our regions. We therefore recommend the systematic performance of hemoglobin electrophoresis in the presence of any chronic hemolytic anemia. 展开更多
关键词 Hemoglobinopathy Homozygous CC Abdominal Pain Hemoglobin Electrophoresis Chauffard Triad
下载PDF
双基线姿态确定三种算法的比较分析 被引量:6
9
作者 刘晓辉 党亚民 +1 位作者 王潜心 杨磊 《大地测量与地球动力学》 CSCD 北大核心 2013年第1期123-127,共5页
利用仿真数据,通过对三种算法在不同情况下解算姿态角精度、代价函数和计算耗时的分析发现,优化TRIAD算法和QUEST算法解算结果完全相同,代价函数随着两基线精度比的降低而减小,姿态角精度与代价函数变化规律不一致,TRIAD算法耗时最少。
关键词 TRIAD 优化TRIAD QUEST 定姿 代价函数
下载PDF
基于恒星敏感器的姿态确定算法研究 被引量:9
10
作者 陈希军 张泽 史话 《控制工程》 CSCD 2008年第3期253-256,298,共5页
星敏感器是一种精度极高的姿态敏感器。基于恒星敏感器的姿态确定问题,从理论上推导了利用TRIAD算法,QUEST算法和Euler-q算法求解姿态矩阵的公式;以Wahba损失函数为指标,利用确定已知的方向余弦阵、恒星观测矢量及在噪声干扰下的星敏感... 星敏感器是一种精度极高的姿态敏感器。基于恒星敏感器的姿态确定问题,从理论上推导了利用TRIAD算法,QUEST算法和Euler-q算法求解姿态矩阵的公式;以Wahba损失函数为指标,利用确定已知的方向余弦阵、恒星观测矢量及在噪声干扰下的星敏感器的观测矢量,对比研究了各种算法的优缺点。利用一个标准星表,通过仿真计算验证了上述三种算法的正确性和有效性。 展开更多
关键词 TRIAD QUEST 姿态确定
下载PDF
一种改进的TRIAD飞行器姿态确定方法 被引量:6
11
作者 陈浩 谭久彬 《系统仿真学报》 EI CAS CSCD 北大核心 2008年第8期2101-2104,共4页
为了提高飞行器姿态测量精度和简化姿态确定的复杂性,提出了一种基于加权矢量和的TRIAD飞行器姿态确定算法。该算法基于TRIAD姿态确定原理,通过对观测矢量加权求和的方式以获得一个较传感器观测矢量更精确的矢量,并以此矢量作为TRIAD算... 为了提高飞行器姿态测量精度和简化姿态确定的复杂性,提出了一种基于加权矢量和的TRIAD飞行器姿态确定算法。该算法基于TRIAD姿态确定原理,通过对观测矢量加权求和的方式以获得一个较传感器观测矢量更精确的矢量,并以此矢量作为TRIAD算法的基准矢量,然后运用TRIAD算法进行姿态计算。仿真结果表明,这种算法获得的飞行器姿态精度优于传统的TRIAD算法,与优化的TRIAD算法精度近似,但简化了姿态确定的过程,提高了姿态确定的速度。 展开更多
关键词 飞行器 姿态确定 矢量观测 TRIAD算法
下载PDF
基于弹载双视场星敏感器求解姿态的几种算法研究 被引量:2
12
作者 肖松 刘朝山 马涛 《光学技术》 CAS CSCD 北大核心 2008年第S1期218-220,共3页
利用弹载星敏感器观测得到的数据,采用三种不同的姿态求解算法,分别计算出了弹体的姿态。通过比较损失函数和处理时间,得出QUEST算法精度高,处理时间短,适用于求解双视场星敏感器的导弹姿态。
关键词 星敏感器 姿态算法 TRIAD QUEST 最小二乘法
下载PDF
基于最优四元数估计的摇摆基座粗对准技术
13
作者 徐景硕 王勇军 唐波 《压电与声光》 CAS CSCD 北大核心 2016年第5期756-759,765,共5页
针对摇摆基座的粗对准问题,提出了一种精度更优的粗对准方法。根据三维坐标矢量与旋转四元数间的内在关系,基于Wahba问题的求解原理,将双观测矢量的最优姿态阵求取问题归结为一个典型三角函数最大值的求解问题。阐述了Wahba问题的求解原... 针对摇摆基座的粗对准问题,提出了一种精度更优的粗对准方法。根据三维坐标矢量与旋转四元数间的内在关系,基于Wahba问题的求解原理,将双观测矢量的最优姿态阵求取问题归结为一个典型三角函数最大值的求解问题。阐述了Wahba问题的求解原理,分析了Wahba问题与最优四元数估计法的关系,剖析了最优四元数估计算法的复共线性,设计了基于最优四元数估计的摇摆基座粗对准方案,并与传统TRIAD算法和最优TRIAD算法进行了应用比较。蒙特卡洛500个样本的仿真结果表明,采用基于最优四元数估计的粗对准法的方位姿态估计精度远优于TRIAD算法和最优TRIAD算法,能使方位失准角的变化幅值控制在角分级,在此基础上能更好实现摇摆基座下惯导系统精对准。 展开更多
关键词 最优四元数估计 TRIAD算法 捷联惯导系统 粗对准 摇摆基座
下载PDF
Chiari三联征(Chiari's triad) 被引量:2
14
作者 田子强 《食管外科电子杂志》 2013年第4期185-,共1页
指各种原因所致的主动脉食管瘘发病时的一组特异性临床表现,首先是胸痛(一般为胸中部疼痛),随即出现前兆性动脉出血,一段时间间隔后出现致命性大出血,这一时间间隔可以是数小时至数天不等。Dubrueil于1818年第一次描述了主动脉食... 指各种原因所致的主动脉食管瘘发病时的一组特异性临床表现,首先是胸痛(一般为胸中部疼痛),随即出现前兆性动脉出血,一段时间间隔后出现致命性大出血,这一时间间隔可以是数小时至数天不等。Dubrueil于1818年第一次描述了主动脉食管瘘这一病症[1]。Chiari于1914年首先描述了主动脉食管瘘三联征并因之得名[2],当时Chiari的描述是胸中部疼痛或吞咽困难,前兆性出血和致命性出血。Carter等于1978年对24例主动脉食管瘘的尸检研究发现[3]:80%的患者在致命性大出血前有前兆性出血。有关Chiari三联征的发生机制, Amin等认为[4],胸痛可能是由于主动脉壁的扩张、腐蚀或局部切割,纵隔炎,食管穿孔,或肿瘤侵犯主动脉、胸膜等所致。前兆出血暂时停止可能是由于动脉壁痉挛,血管内压力下降或主动脉周围血肿等因素而致瘘口暂时闭塞。随后闭塞的瘘口被感染或胃肠道消化液再次腐蚀掉,出现致命性大出血。Chiari三联征可发生于任何原因所致的主动脉食管瘘患者,包括主动脉夹层动脉瘤,食管及气管的恶性肿瘤,手术后并发症,食管异物等。Chiari三联征的提出对我们进一步认识主动脉食管瘘这一高度致命性疾病的发病机制及发病规律具有重大的理论意义和临床价值。在前兆性出血后的数小时至数天的时间内,外科医生有了较充足的诊断及处理时间,使得主动脉食管瘘的手术治愈成为可能[5]。 展开更多
关键词 三联征 Chiari’s triad 前兆 患者 疼痛 主动脉食管瘘 CHIARI
下载PDF
能量平台中结扎束在阴式子宫全切手术中的应用 被引量:1
15
作者 索静 《内蒙古医学杂志》 2014年第7期790-792,共3页
目的探讨Force Triad能量平台中血管结扎闭合系统(结扎束)在阴式子宫全切术(Transvaginal total hysterectomy,TVH)中的应用价值。方法 2013年4~12月住院患者60例,随机分成观察组(ligasuren血管闭合系统组)与对照组(传统手术组)... 目的探讨Force Triad能量平台中血管结扎闭合系统(结扎束)在阴式子宫全切术(Transvaginal total hysterectomy,TVH)中的应用价值。方法 2013年4~12月住院患者60例,随机分成观察组(ligasuren血管闭合系统组)与对照组(传统手术组),比较两组间在手术时间、术中出血量、术后排气时间、术后发热时间、术后离床活动时间以及平均住院天数等情况。结果观察组手术时间、术中出血量、术后离床活动时间及平均住院时间明显少于开腹手术组(P〈0.05),差异有统计学意义;术后排气时间、术后发热时间差异均无显著性(P〉0.05)。结论 Ligasuren血管闭合系统在阴式子宫全切手术的应用方面有一定的优势,可以更有效地闭合血管,减少出血量及缩短手术时间,减少术后并发症等优点,值得推广。 展开更多
关键词 FORCE Triad能量平台 结扎束血管闭合系统 阴式子宫全切术
下载PDF
Occurrence of Fibonacci numbers in development and structure of animal forms: Phylogenetic observations and epigenetic significance
16
作者 John J. Wille 《Natural Science》 2012年第4期216-232,共17页
A survey of zoological literature affirmed the wide occurrence of Fibonacci numbers in the organization of acellular and prokaryotic life forms as well as in some eukaryotic protistans and in the embryonic development... A survey of zoological literature affirmed the wide occurrence of Fibonacci numbers in the organization of acellular and prokaryotic life forms as well as in some eukaryotic protistans and in the embryonic development and adult forms of many living and fossil remains of metazoan animals. A detailed comparative analysis of the axial skeleton of a fossil fish and humans revealed a new rule of the “nested triad” of bones organized along the proximal to distal axis of limb appendages. This growth pattern and its ubiquity among living vertebrates appear to underlie a profound rule of pattern formation that is dictated in part by the genetics and epigenetic mechanisms of stem cell clonal development. 展开更多
关键词 ANIMAL Body Plan FIBONACCI Numbers (n) HOX Genes Nested triads Phylogeny Recursive Transition Networks Segmentation
下载PDF
融合TRIAD算法用于GPS姿态确定 被引量:11
17
作者 黎湧 吴宏鑫 刘良栋 《中国空间科学技术》 CSCD 北大核心 2000年第2期30-37,共8页
研究把观测矢量定姿算法用于 GPS姿态确定。传统的 TRIAD算法利用两个非平行矢量确定载体的三轴姿态 ,但它存在对主矢量敏感 ,且不能利用第3根矢量的测量信息等缺点。文章提出一种改进的 TRIAD算法 ,克服了主矢量敏感问题 ;为了能利用 ... 研究把观测矢量定姿算法用于 GPS姿态确定。传统的 TRIAD算法利用两个非平行矢量确定载体的三轴姿态 ,但它存在对主矢量敏感 ,且不能利用第3根矢量的测量信息等缺点。文章提出一种改进的 TRIAD算法 ,克服了主矢量敏感问题 ;为了能利用 3根基线的观测信息 ,在 OPTTRIAD算法的基础上提出融合TRIAD算法 ,它可以提高定姿精度。用接收机进行了实验 ,结果表明改进的TRIAD算法确实克服了主矢量敏感问题 ;较之传统的 TRIAD算法 ,融合 TRIAD算法的偏航角、俯仰角和滚动角精度分别提高了 35 % ,19%和 34 % 展开更多
关键词 全球定位系统 姿态确定 融合算法 TRIAD GPS卫星
下载PDF
TRIaD指标与药物所致的尖端扭转性室性心动过速 被引量:3
18
作者 关敬树 徐涛 +1 位作者 王昊 廖德宁 《中国心脏起搏与心电生理杂志》 2012年第2期98-100,共3页
以往人们多认为QT间期延长是药源性尖端扭转性室性心动过速(TdP)的重要机制。但是QT间期延长并不都能引发TdP,而TdP的发生也并不都伴随着QT间期延长,甚至在一些QT间期缩短的情况下,也有恶性室性心律失常的发生。因此近年来有学者提出TR... 以往人们多认为QT间期延长是药源性尖端扭转性室性心动过速(TdP)的重要机制。但是QT间期延长并不都能引发TdP,而TdP的发生也并不都伴随着QT间期延长,甚至在一些QT间期缩短的情况下,也有恶性室性心律失常的发生。因此近年来有学者提出TRIaD的概念,其为心肌细胞动作电位三角形化(triangulation)、逆向频率依赖性(reverse use dependency)、不稳定性(instability)以及离散(dispersion)等指标的合称。越来越多的研究证明,TRIaD指标的变化是药源性TdP发生的共同基质;药物应用后表现出动作电位三角形化、逆向频率依赖性、不稳定性、离散增加等反应,无论有无QT间期的延长,均易发生室性心律失常,包括TdP。反之,即使QT间期延长,致心律失常作用也很小。 展开更多
关键词 电生理学 尖端扭转型室性心动过速 综述 QT间期 TRIAD
下载PDF
面向测量误差模型的外生变量估计方法 被引量:1
19
作者 谢峰 蔡瑞初 +1 位作者 曾艳 郝志峰 《计算机应用研究》 CSCD 北大核心 2021年第2期456-459,共4页
从观察数据中发现因果关系在近年来得到了越来越多学者的关注,其中外生变量在理解因果机制中扮演者重要的角色。然而,现有的因果发现方法大多假设观察变量就是真实发生的因(果)变量,忽略了测量误差带来的影响。为此,提出了一种解决测量... 从观察数据中发现因果关系在近年来得到了越来越多学者的关注,其中外生变量在理解因果机制中扮演者重要的角色。然而,现有的因果发现方法大多假设观察变量就是真实发生的因(果)变量,忽略了测量误差带来的影响。为此,提出了一种解决测量模型下的外生变量估计方法。通过引入triad约束,根据此约束来找出与其余所有相关成对变量都满足triad约束的变量,即外生变量。该算法不仅能够解决含有测量误差数据的估计问题,而且对于没有测量误差的数据仍然适用。实验将该算法应用于真实网络产生的数据中,结果表明,无论变量是否含有测量误差,提出方法均优于现有的其他算法。同时,基于移动基站的真实数据实验也验证了算法的有效性。 展开更多
关键词 测量误差模型 外生变量 因果关系 triad约束 非高斯
下载PDF
Expression of fragile histidine triad in primary hepatocellular carcinoma and its relation with cell proliferation and apoptosis 被引量:33
20
作者 Ke-JunNan Zhi-PingRuan +4 位作者 ZhaoJing Hai-XiaQin Hong-YanWang HuiGuo RuiXu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第2期228-231,共4页
AIM: To evaluate the expression of fragile histidine triad (FHIT) gene protein, product of a candidate tumor suppressor, and to investigate the relationship between FHIT, cell apoptosis and proliferation, and patholog... AIM: To evaluate the expression of fragile histidine triad (FHIT) gene protein, product of a candidate tumor suppressor, and to investigate the relationship between FHIT, cell apoptosis and proliferation, and pathological features of primary hepatocellular carcinoma (HCC). METHODS: Forty-seven HCC and ten normal liver specimens were collected during surgical operation between 2001 and 2003. FHIT and proliferating cell nuclear antigen (PCNA) expression were detected by immunohistochemistry, and apoptotic level was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay on the tissue sections. RESULTS: All normal liver tissues showed a strong expression of FHIT, whereas 28 of 47 (59.6%) carcinomas showed a significant loss or absence of FHIT expression (P= 0.001). The proportion of reduced FHIT expression in those carcinomas at stages Ⅲ-Ⅳ (70.6%) and in those with extrahepatic metastasis (86.7%) showed an increasing trend compared with those at stages HI (30.8%, P= 0.013) and those without metastasis (46.9%, P = 0.010) respectively. Apoptotic incidence in advanced TNM stage carcinoma and those with positive FHIT expression was higher than that in early stage carcinoma (P=0.030) and in those with negative FHIT expression (P=0.044) respectively. The proliferating potential of hepatocellular carcinoma was associated with FHIT expression (P= 0.016) and the aggressive feature (P = 0.019). Kaplan-Meier analysis demonstrated that the survival time of these 47 patients correlated with TNM stage, FHIT expression and metastasis. CONCLUSION: There is marked loss or absence of FHIT expression, as well as abnormal apoptosis-prdiferation balance in HCC. FHIT may play an important role in carcinogenesis and development of HCC. 展开更多
关键词 Hepatocellular carcinoma Fragile histidine triad protein Cell proliferation APOPTOSIS
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部