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Yuan-yuan Wang

Publications and source records attributed to Yuan-yuan Wang.

6 recordsLinked to original sources
PubMed2006

Identification and analysis of multimode guided waves in tibia cortical bone.

The hollow cylinder model filled with viscous-liquid is performed to simulate tibial bone shape in this paper. Short time Fourier transform (STFT) was applied to identify and analyze guided wave modes of a series of ultrasonic signals acquired at various transmitter-receiver positions for a fixed transmitter. Experimental results were compared with theoretical simulation. The high correlation values for group velocity were obtained between results of experiment and theory for L(0,2) (r=0.89, p<10(-5)), and L(0,3) (r=0.87, p<10(-5)). The experimental group velocities correlated strongly with cortical thickness (cortTh) for L(0,2) (r(2)=0.79, p<10(-5)) and L(0,3) (r(2)=0.74, p<10(-5)) at 0.5 MHz center frequency. The results showed that the STFT is an effective method to identify the propagating modes and derive dispersion information. The experimental results were in good agreement with theoretical predictions. This study suggests that the guided wave L(0,2) mode is a promising mode to assess change in cortical thickness.

Algorithms↗
PubMed2006

[A study on HLA-DQB1 allele associated with genetic susceptibility to duodenal ulcer in Guangdong Hans].

OBJECTIVE: To study the genetic susceptibility of HLA-DQB1 alleles to duodenal ulcer in Chinese Hans from Guangdong area around. METHODS: Hundred and five patients with duodenal ulcer and hundred and five healthy controls were examined for HLA-DQB1 genotypes. HLA-DQB1 allele typing was carried out by polymerase chain reaction with sequence specific primers (PCR-SSP). RESULTS: The allele frequency of HLA-DQB1*0602 in patients with duodenal ulcer (64.8%) was significantly higher than that in healthy controls (14.3%). CONCLUSION: These findings suggest that HLA-DQB1*0602 is a susceptible gene to duodenal ulcer in Guangdong Hans of China. And at HLA-DQB1 site, there are immunogenetic differences between duodenal ulcer patients and healthy controls.

Adolescent↗
PubMed2006

[Study on the relationship between the degree of periportal fibrosis, hepatic parenchymatous fibrosis and diameter of portal vein in Schistosoma japonicum infection].

The degree of periportal fibrosis, hepatic parenchymatous fibrosis and the diameter of portal vein in fishermen from highly endemic area of schistosomiasis japonica in Dongting Lake region were measured. The results showed a significant correlation between the degree of periportal fibrosis and parenchymatous fibrosis and the portal venous diameter with a correlation coefficient of 0.375 and 0.332 respectively. The authors consider that the diameter of the portal vein can be used to assess the hepatic morbidity of patients.

Adult↗
PubMed2004

[Coronary resistance system in evaluation of microvascular dysfunction after intracoronary microembolization: an experimental study].

OBJECTIVE: To assess the microvascular function of coronary artery after intracoronary microembolization using coronary resistance system. METHODS: The left anterior descending coronary artery (LAD) of 10 pigs weighing 21 kg-25 kg were embolized by repetitive injection of microspheres 45 micro m in diameter through a 2.8F Tracker catheter. Intra-vascular ultrasound (IVUS) images, intracoronary Doppler and pressure signals in the middle segment of LAD were acquired by use of intracoronary ultrasound imaging catheter, Doppler flow wire and pressure wire separately. Intracoronary bolus injection of 18 micro g adenosine was administered to maximally vasodilate the coronary arterial bed through the 2.8F Tracker catheter. The resting and hyperemic signals were acquired respectively before microembolization and in different levels of microembolization. Coronary resistance system reflecting the resistance to pulsatile coronary flow was established by a self-made software of PC system. The resting and hyperemic CR parameters included average resting coronary resistance (rCR) and average minimal coronary resistance (min-CR), the first-harmonic rCR and min-CR, the first-harmonic rCR orientation and min-CR orientation, and so on. Factor analysis was performed to extract the best coronary parameter from the coronary resistance parameters. RESULTS: Factor analysis showed that the first-harmonic rCR and first-harmonic min-CR were correlated better with the first component extracted from the resting and hyperemic CR parameters than rCR and min-CR, with the correlation coefficient being 0.913 and 0.950 in the first-harmonic CR and first-harmonic min-CR respectively. No significant difference in min-CR was found between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. The min-CR value increased markedly from 271 mm Hg.ml(-1).s(-1) +/- 99 mm Hg.ml(-1).s(-1) at the dosage of injecting 5 x 10(4) microspheres to 361 mm Hg.ml(-1).s(-1) +/- 158 mm Hg.ml(-1).s(-1) at the dosage of injecting 10 x 10(4) microspheres (P < 0.05). The min-CR value remained almost unchanged from the dosage of 10 x 10(4) to 15 x 10(4) microspheres. There was no significant difference concerning the first-harmonic min-CR between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. Along with the increase of number of microspheres injected the min-CR value increased gradually. The min-CR value was increased significantly than that before microembolization since the number of microspheres injected surpassed 14 x 10(4). CONCLUSION: The first-harmonic min-CR reflected the coronary microvascular dysfunction in different extents of microembolization better than min-CR. The extent of coronary microvascular dysfunction wasn't linearly related to the extent of microembolization.

Animals↗