115 research outputs found
Analytical simulation on experimental seismic response of headed anchors embedded in reinforced concrete
This paper deal with a series of dynamic response analyses, carried out to give numerical correlation of hysteretic behavior of cast-in-place anchorages obtained by the static loading and shake table tests. Specimens for the analyses are reinforced concrete rectangular blocks with embedded headed anchors. Failure modes expected are the steel bolt failure and the concrete cone failure, associated with the respective embedment depth. Initial flexural cracks presumed seismic damage on the concrete block is developed with bending loading. In the analytical model, nonlinear hysteretic behavior of the anchorage is idealized by translational and rotational springs in which properties estimated from the hysteretic loops of the static loading tests. It was shown that the overall force and displacement performance under dynamic loads are well simulated based on the analytical models presented herein
Optical Coherence Tomography Analysis of Attenuated Plaques Detected by Intravascular Ultrasound in Patients with Acute Coronary Syndromes
Background. Recent intravascular ultrasound (IVUS) studies have demonstrated that hypoechoic plaque with deep ultrasound attenuation despite absence of bright calcium is common in acute coronary syndrome. Such “attenuated plaque” may be an IVUS characteristic of unstable lesion.
Methods. We used optical coherence tomography (OCT) in 104 patients with unstable angina to compare lesion characteristics between IVUS-detected attenuated plaque and nonattenuated plaque.
Results. IVUS-detected attenuated plaque was observed in 41 (39%) patients. OCT-detected lipidic plaque (88% versus 49%, P < 0.001), thin-cap fibroatheroma (48% versus 16%, P < 0.001), plaque rupture (44% versus 11%, P < 0.001), and intracoronary thrombus (54% versus 17%, P < 0.001) were more often seen in IVUS-detected attenuated plaques compared with nonattenuated plaques.
Conclusions. IVUS-detected attenuated plaque has many characteristics of unstable coronary lesion. The presence of attended plaque might be an important marker of lesion instability
Field-induced quantum phase in a frustrated zigzag-square lattice
This study presents the experimental realization of a spin-1/2 zigzag-square
lattice in a verdazyl-based complex, namely
(-Py-V-2,6-F)Cu(hfac). Molecular orbital calculations suggest
the presence of five types of frustrated exchange couplings. Our observations
reveal an incremental increase in the magnetization curve beyond a critical
field, signifying a phase transition from the antiferromagnetic ordered state
to a quantum state characterized by a 1/2 plateau. This intriguing behavior
arises from the effective stabilization of a zigzag chain by the external
fields. These results provide evidence for field-induced dimensional reduction
in a zigzag-square lattice attributed to the effects of frustration.Comment: 5 pages, 4 figure
The Anti-Obesity Effect of the Palatinose-Based Formula Inslow is Likely due to an Increase in the Hepatic PPAR-α and Adipocyte PPAR-γ Gene Expressions
Abdominal obesity is a principal risk factor in the development of metabolic syndrome. Previously, we showed that a palatinose-based liquid formula, Inslow/MHN-01, suppressed postprandial plasma glucose level and reduced visceral fat accumulation better than the standard formula (SF). To elucidate the mechanism of Inslow-mediated anti-obesity effect, expression levels of genes involved in the glucose and lipid metabolism were compared in Inslow- and SF-fed rats. Both fasting plasma insulin level and average islet sizes were reduced in the Inslow group. We also found less abdominal fat accumulation and reduced hepatic triacylglycerol content in the Inslow group. Expression of the β-oxidation enzymes and uncoupling potein-2 (UCP-2) mRNAs in the liver of the Inslow group were higher than the SF group, which was due to a concomitant higher expression of the peroxisome proliferator-activated receptor (PPAR)-α mRNA in the former. Furthermore, expression of the UCP-2 and adiponectin mRNAs in the epididymal fat were higher in the Inslow group than the SF group, and were stimulated by a concomitant increase of the PPAR-γ gene expression in the former. These results strongly suggested that the anti-obesity effect of Inslow was due to an increase in the hepatic PPAR-α and adipocyte PPAR-γ gene expressions
Assessment of Culprit Lesion Morphology in Acute Myocardial Infarction Ability of Optical Coherence Tomography Compared With Intravascular Ultrasound and Coronary Angioscopy
ObjectivesThe aim of the present study was to evaluate the ability of optical coherence tomography (OCT) for assessment of the culprit lesion morphology in acute myocardial infarction (AMI) in comparison with intravascular ultrasound (IVUS) and coronary angioscopy (CAS).BackgroundOptical coherence tomography is a new intravascular imaging method with a high resolution of approximately 10 μm. This may allow us to assess the vulnerable plaques in detail in vivo.MethodsWe enrolled 30 patients with AMI, and analyzed the culprit lesion by OCT, CAS, and IVUS.ResultsThe average duration from the onset of symptom to OCT imaging was 3.8 ± 1.0 h. The incidence of plaque rupture observed by OCT was 73%, and it was significantly higher than that by CAS (47%, p = 0.035) and IVUS (40%, p = 0.009). Furthermore, OCT (23%) was superior to CAS (3%, p = 0.022) and IVUS (0%, p = 0.005) in the detection of fibrous cap erosion. The intracoronary thrombus was observed in all cases by OCT and CAS, but it was identified in 33% by IVUS (vs. OCT, p < 0.001). Only OCT could estimate the fibrous cap thickness, and it was 49 ± 21 μm. The incidence of thin cap fibroatheroma (TCFA) was 83% in this population by OCT.ConclusionsOptical coherence tomography is a feasible imaging modality in patients with AMI and allows us to identify not only plaque rupture, but also fibrous cap erosion, intracoronary thrombus, and TCFA in vivo more frequently compared with conventional imaging techniques
Implication of Plaque Color Classification for Assessing Plaque Vulnerability A Coronary Angioscopy and Optical Coherence Tomography Investigation
ObjectivesThe purpose of this study was to assess the relationship between plaque color evaluated by coronary angioscopy and fibrous cap thickness estimated by optical coherence tomography (OCT) in vivo.BackgroundYellow color intensity of coronary plaque evaluated by coronary angioscopy might be associated with plaque vulnerability.MethodsSeventy-seven coronary artery plaques in patients with acute coronary syndrome were observed by angioscopy and OCT. Plaque color was graded as white, light yellow, yellow, or intensive yellow.ResultsThere were significant differences among the groups classified by plaque color with respect to the fibrous cap thickness estimated by OCT: 389 ± 74 μm in white plaques, 228 ± 51 μm in light yellow plaques, 115 ± 28 μm in yellow plaques, and 59 ± 14 μm in intensive yellow plaques (p < 0.0001). In Spearman rank-order correlation analysis, there was a significant negative correlation between yellow color intensity and fibrous cap thickness (p < 0.0001). Furthermore, 80% of intensive yellow plaques were thin cap fibroatheroma with a cap thickness of ≤65 μm.ConclusionsThe plaque color in coronary angioscopy was determined by the fibrous cap thickness, which was assessed by OCT. Although coronary angioscopy remains a specialized research tool, it might allow us to evaluate plaque vulnerability
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