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31.
Purpose For tissue characterization of the arterial wall, we developed a “phased tracking” method to measure the strain (change in
wall thickness) and elasticity of the arterial wall. To improve the accuracy of tissue characterization, we are now attempting
to measure other mechanical properties in addition to elasticity.
Methods In this study, the change in elasticity during the cardiac diastole was measured with ultrasound by generating a change in
internal pressure using remote cyclic actuation.
Results From the measured change in elasticity during cardiac diastole, the nonlinear property in the stress–strain relationship of
the artery wall was estimated. In basic experiments using a silicone rubber tube and in vivo experiments in human carotid
arteries.
Conclusion The proposal method enables the noninvasive measurement of the nonlinear mechanical property in addition to the elasticity
of the arterial wall. 相似文献
32.
我国登革2型病毒43株包膜E蛋白基因的特征 总被引:2,自引:0,他引:2
对我国1987年流行的登革2型病毒43株包膜E蛋白基因的核苷酸序列进行了分析。结果表明登革2型病毒43株包膜E蛋白基因核苷酸序列含1485个核苷酸,编码495个氨基酸,并就其核苷酸序列及其相应的氨基酸序列与其它的登革2型病毒株进行了比较,发现核苷酸序列与我国1985年分离的登革2型病毒04株,新几内亚C株(NGC),牙买加株1409(JAM)和马来西亚当地流行株M1(登革出血热)、血2(登革休克综合征)、M3(登革热)同源性分别是95.8%、94.6%、97.5%、925%、92.7%和939%,氨基酸序列的同源性分别是94.3%、94.3%、96.0%、93.7%、93.7%和91.5%,推断出的氨基酸序列显示出12个保守的半胱氨酸残基和两个潜在的糖基化位点,分别位于Asn-67和Asn-153位。 相似文献
33.
McConaghy (1989) argued that the validity of penile circumference responses (PCRs) is at best unestablished and that penile volume responses (PVRs) have been demonstrated to be clearly superior indices of sexual arousal and orientation. In his critique, McConaghy stated that (i) penile erection has been incorrectly identified with sexual arousal, (ii) that PCRs have not been shown to accurately discriminate between divergent patterns of sexual arousal (including paraphilias), (iii) that the methodologies used to compare the two types of transducers are inappropriate, and (iv) that PCRs should not be used for diagnostic and treatment decisions. In this paper, McConaghy's criticisms are reviewed in the context of the existing literature on the subject. Although PCRs and PVRs involve different methodologies, they generally yield results that bear more similarities than differences. Furthermore, there is an extensive and growing literature on the use of PCR measures with various paraphilias. Several of McConaghy's arguments should be considered tentative while others are clearly unsubstantiated. Most of McConaghy's concerns over the validity and uses of PCR measures are empirical questions. Suggestions for future research are offered. 相似文献
34.
35.
目的研究低浓度5-Fu 24-小时持续化疗和高浓度5-Fu短时间化疗对BEL-7402肝癌细胞株的细胞周期的影响:方法用低浓度(1000.0μg/L)的5.Fu对BEL-7402肝癌细胞株进行持续24小时的培养(A组),用高浓度(50000.0μg/L)的5-Fu对BEL-1 7402肝癌细胞株进行2小时培养(B组),在培养后的不同时间点用流式细胞技术检测细胞周期的变化。结果A组结果显示:0h、4h、8h、12h、16h、20h和24h的S期细胞的百分数分别为25.23%、32.35%、39.28%、41.05%、46.02%、47.00%及47.14%。B组结果显示:0h、4h、8h、12h、16h、20h和24h的S期细胞的百分数分别为24.68%、68.43%、46.67%、43.67%、35.42%、33.22%及32.96%。结论5-Fu引起的S期细胞周期阻滞不但和浓度相关,也和作用时间相关。低浓度(1000.0μg/L)的5-Fu持续化疗较高浓度(50000.0μg/L)的5-Fu短时间(2小时)化疗更容易引起BEL-7402肝癌细胞株S期阻滞。 相似文献
36.
Objective. To determine if patients treated at hospitals under different levels of financial strain from the Balanced Budget Act (BBA) of 1997 had differential changes in 30-day mortality, and whether vulnerable patient populations such as the uninsured were disproportionately affected.
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured. 相似文献
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured. 相似文献
37.
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39.
牵张力作用下培养的人牙周膜成纤维细胞生成NO的实验研究 总被引:3,自引:1,他引:2
目的:观察在机械牵张力作用下牙周膜成纤维细胞NO的生成情况以及iNOS的表达情况。方法:用自行研制的细胞加载系统,对培养至第4代的人牙周膜成纤维细胞施以频率为每分钟6个周期(5s拉伸,5s松弛)、拉伸率为12%的牵张力,分别于加载后3,10,20,40,60min取上清液进行NO含量检测;以及于加载24,48,96h后固定细胞,进行iNOS免疫组化反应。结果:NO含量在所研究时间范围内逐渐增加;iNOS免疫组化结果显示iNOS的染色强度随着作用时间延长而增强。结论:牙周膜成纤维细胞在机械牵张力作用下合成NO增多,它可能通过合成和释放NO这一途径,在应力作用下的牙周组织改建过程中起作用。 相似文献
40.
本实验应用流式细胞光度术研究鼻咽癌上皮样细胞株(CNE)的细胞周期动力学。结果发现CNE细胞仍保持原代细胞的DNA含量水平(超三倍体和亚四倍体),随着细胞接种时间的延长细胞周期中G0/G1时相细胞的百分数逐渐升高,而S%和G2+M%则逐渐降低。该项研究还发现随着孵育时间的延长,细胞周期中各时相细胞的运动均逐渐延缓,其中以G0/G1和G2+M时相细胞的运动减慢较为明显。 相似文献