The authors obtain a new property of the n-dimensional binary undirected de Bruijn graph UB(n)for n≥4,namely,there is a vertex x such that for any other vertex y there exist at least two internally disjoint paths of ...The authors obtain a new property of the n-dimensional binary undirected de Bruijn graph UB(n)for n≥4,namely,there is a vertex x such that for any other vertex y there exist at least two internally disjoint paths of length at most n-1 between x and y in UB(n).The result means that the(n-1,2)-dominating number of UB(n)is equal to one if n≥4.展开更多
目的:检验全身低剂量计算机断层扫描(LDCT)评估多发性骨髓瘤骨病的效能。方法:对2019-02-2019-06在我院确诊为多发性骨髓瘤且接受全身数字X线摄影(DR)检查的共40例患者行全身LDCT复查(间隔不超过30 d),在病灶识别、D-S临床分期、辐射剂...目的:检验全身低剂量计算机断层扫描(LDCT)评估多发性骨髓瘤骨病的效能。方法:对2019-02-2019-06在我院确诊为多发性骨髓瘤且接受全身数字X线摄影(DR)检查的共40例患者行全身LDCT复查(间隔不超过30 d),在病灶识别、D-S临床分期、辐射剂量、检查时长、患者耐受度、意外发现方面进行两两比较(配对t检验或Wilcoxon符号秩和检验)。结果:LDCT与DR检出全身平均溶骨性病灶个数分别为69.9 vs 31.2,DR总漏诊率55.3%,差异有统计学意义(P<0.001);肩胛骨、颈椎、锁骨、胸椎、肋骨、腰椎、胸骨、骨盆依次为DR漏诊率>50.0%的部位。共6例(15.0%)患者D-S临床分期不一致(LDCT vs DR)。LDCT与DR的有效辐射剂量(ED)、检查时长、耐受度分别为9.4 mSv vs 3.6 mSv,3.5 min vs 16.6 min,100%好vs 65%中、35%差,差异均有统计学意义(P<0.001)。股骨髓腔浸润(85.0%)、肱骨髓腔浸润(72.5%)、肋骨骨折(35.0%)、髓外浸润(17.5%)依次为LDCT常见的重要意外发现。结论:LDCT在溶骨性病灶识别、D-S临床分期、检查时长、患者耐受度、意外发现方面均明显优于DR,且辐射剂量较低。展开更多
基金National Natural Science Foundation of China(No.19971086,19871040)Jiangsu Provincial Natural Science Foundation of China
文摘The authors obtain a new property of the n-dimensional binary undirected de Bruijn graph UB(n)for n≥4,namely,there is a vertex x such that for any other vertex y there exist at least two internally disjoint paths of length at most n-1 between x and y in UB(n).The result means that the(n-1,2)-dominating number of UB(n)is equal to one if n≥4.
文摘目的:检验全身低剂量计算机断层扫描(LDCT)评估多发性骨髓瘤骨病的效能。方法:对2019-02-2019-06在我院确诊为多发性骨髓瘤且接受全身数字X线摄影(DR)检查的共40例患者行全身LDCT复查(间隔不超过30 d),在病灶识别、D-S临床分期、辐射剂量、检查时长、患者耐受度、意外发现方面进行两两比较(配对t检验或Wilcoxon符号秩和检验)。结果:LDCT与DR检出全身平均溶骨性病灶个数分别为69.9 vs 31.2,DR总漏诊率55.3%,差异有统计学意义(P<0.001);肩胛骨、颈椎、锁骨、胸椎、肋骨、腰椎、胸骨、骨盆依次为DR漏诊率>50.0%的部位。共6例(15.0%)患者D-S临床分期不一致(LDCT vs DR)。LDCT与DR的有效辐射剂量(ED)、检查时长、耐受度分别为9.4 mSv vs 3.6 mSv,3.5 min vs 16.6 min,100%好vs 65%中、35%差,差异均有统计学意义(P<0.001)。股骨髓腔浸润(85.0%)、肱骨髓腔浸润(72.5%)、肋骨骨折(35.0%)、髓外浸润(17.5%)依次为LDCT常见的重要意外发现。结论:LDCT在溶骨性病灶识别、D-S临床分期、检查时长、患者耐受度、意外发现方面均明显优于DR,且辐射剂量较低。