Cap Thickness Research Articles

Concomitant Coronary Atheroma Regression and Stabilization in Response to Lipid-Lowering Therapy

BackgroundThe frequency, characteristics, and outcomes of patients treated with high-intensity lipid-lowering therapy and showing concomitant atheroma volume reduction, lipid content reduction, and increase in fibrous cap thickness (ie, triple regression) are unknown. ObjectivesThis study was designed to investigate rates, determinants, and prognostic implications of triple regression in patients presenting with acute myocardial infarction and treated with high-intensity lipid-lowering therapy. MethodsThe PACMAN-AMI (Effects of the PCSK9 Antibody Alirocumab on Coronary Atherosclerosis in Patients with Acute Myocardial Infarction) trial used serial intravascular ultrasound, near-infrared spectroscopy, and optical coherence tomography to compare the effects of alirocumab vs placebo in patients receiving high-intensity statin therapy. Triple regression was defined by the combined presence of percentage of atheroma volume reduction, maximum lipid core burden index within 4 mm reduction, and minimal fibrous cap thickness increase. Clinical outcomes at 1-year follow-up were assessed. ResultsOverall, 84 patients (31.7%) showed triple regression (40.8% in the alirocumab group vs 23.0% in the placebo group; P = 0.002). On-treatment low-density lipoprotein cholesterol levels were lower in patients with vs without triple regression (between-group difference: −27.1 mg/dL; 95% CI: −37.7 to −16.6 mg/dL; P < 0.001). Triple regression was independently predicted by alirocumab treatment (OR: 2.83; 95% CI: 1.57-5.16; P = 0.001) and a higher baseline maximum lipid core burden index within 4 mm (OR: 1.03; 95% CI: 1.01-1.06; P = 0.013). The composite clinical endpoint of death, myocardial infarction, and ischemia-driven revascularization occurred less frequently in patients with vs without triple regression (8.3% vs 18.2%; P = 0.04). ConclusionsTriple regression occurred in one-third of patients with acute myocardial infarction who were receiving high-intensity lipid-lowering therapy and was associated with alirocumab treatment, higher baseline lipid content, and reduced cardiovascular events. (Vascular Effects of Alirocumab in Acute MI-Patients [PACMAN-AMI]; NCT03067844)

Polymer-coated fiber-optic Fabry-Perot interferometer-based temperature sensor with high sensitivity

In this paper, a highly sensitive temperature sensor based on polymer-coated Fabry-Perot interferometer (FPI) is proposed and demonstrated. The FPI temperature sensor consists of the end face of single-mode fiber (SMF) and the Polydimethylsiloxane (PDMS) cap on the end face. By varying the number of coatings, the thickness of the PDMS cap can be flexibly controlled to obtain FPI sensors with different cavity lengths. The temperature sensitivity is studied experimentally from −30 °C to 85 °C, and it is found that the sensor shows different sensitivity in different temperature intervals, up to 0.698 nm/°C. Compared to similarly constructed sensors, the sensor in this paper has a large temperature range while maintaining a high sensitivity. In addition, the performance of the sensor is tested by experiments and the results show that the sensor possesses the advantages of good stability, fast response time and good repeatability.

Quantitative imaging biomarkers of coronary plaque morphology: insights from EVAPORATE.

Residual cardiovascular risk persists despite statin therapy. In REDUCE-IT, icosapent ethyl (IPE) reduced total events, but the mechanisms of benefit are not fully understood. EVAPORATE evaluated the effects of IPE on plaque characteristics by coronary computed tomography angiography (CCTA). Given the conclusion that the IPE-treated patients demonstrate that plaque burden decreases has already been published in the primary study analysis, we aimed to demonstrate whether the use of an analytic technique defined and validated in histological terms could extend the primary study in terms of whether such changes could be reliably seen in less time on drug, at the individual (rather than only at the cohort) level, or both, as neither of these were established by the primary study result. EVAPORATE randomized the patients to IPE 4 g/day or placebo. Plaque morphology, including lipid-rich necrotic core (LRNC), fibrous cap thickness, and intraplaque hemorrhage (IPH), was assessed using the ElucidVivo® (Elucid Bioimaging Inc.) on CCTA. The changes in plaque morphology between the treatment groups were analyzed. A neural network to predict treatment assignment was used to infer patient representation that encodes significant morphological changes. Fifty-five patients completed the 18-month visit in EVAPORATE with interpretable images at each of the three time points. The decrease of LRNC between the patients on IPE vs. placebo at 9 months (reduction of 2 mm3 vs. an increase of 41 mm3, p = 0.008), widening at 18 months (6 mm3 vs. 58 mm3 increase, p = 0.015) were observed. While not statistically significant on a univariable basis, reductions in wall thickness and increases in cap thickness motivated multivariable modeling on an individual patient basis. The per-patient response assessment was possible using a multivariable model of lipid-rich phenotype at the 9-month follow-up, p < 0.01 (sustained at 18 months), generalizing well to a validation cohort. Plaques in the IPE-treated patients acquired more characteristics of stability. Reliable assessment using histologically validated analysis of individual response is possible at 9 months, with sustained stabilization at 18 months, providing a quantitative basis to elucidate drug mechanism and assess individual patient response.

Atomistic approach to the strain field in finite-sized heterostructures

The numerical code AS_LBFG_v2 developed to simulate the atomic elastic relaxation in finite-sized heterostructures is introduced. To minimize the elastic energy the L-BFGS algorithm is utilized. A user-defined initial atomic configuration, without restrictions on the shape of the matrix embedding quantum dot (QD), can be implemented in the code. By enlarging the pyramidal QD heterostructure towards mesoscopic size, the code generates a strain field distribution similar to that obtained by continuum model for weakly polar semiconductors. The strain field obtained for semi-torus, and spherical shape QDs embedded in finite-sized matrices is also presented. The dependence of the strain field on the cap thickness and the distribution of misfit dislocations in the relaxed configuration are simulated by the code. Program summaryProgram titles:AS_LBFG_v2, AS_Calc_v2CPC Library link to program files:https://doi.org/10.17632/53dshkskct.1Code Ocean capsule:https://codeocean.com/capsule/5342364/tree/v1 and https://codeocean.com/capsule/9050452/tree/v1Licensing provisions: MIT licenseProgramming language: FORTRANNature of problem: An initial constraint atomic configuration of a heterostructure is relaxed by imposing Keating's elastic interaction. The strain field and distribution of misfit dislocations are simulated for various quantum dot shapes and heterostructure materials.Solution method: The elastic energy of the heterostructure is minimized by an L-BFGS algorithm. The strain field is calculated by a discrete mathematical expression at each atomic location.

Rational Design of a Double-Locked Photoacoustic Probe for Precise In Vivo Imaging of Cathepsin B in Atherosclerotic Plaques.

Atherosclerotic plaque rupture is a significant cause of acute cardiovascular events such as heart attack and stroke, triggered by the decomposition of fiber caps induced by cysteine cathepsin. However, the accurate measurement of cathepsin B (CTB) activity in plaques is challenging due to the low specificity and insufficient penetration depth of available atherosclerosis-associated cathepsin fluorescent probes, hampering reliable assessment of plaque vulnerability. To address these limitations, we added both lipophilic alkyl chain and hydrophilic CTB substrate to the hemicyanine scaffold to develop a lipid-unlocked CTB responsive probe (L-CRP) that uses lipids and CTB as two keys to unlock photoacoustic (PA) signals for measuring CTB activity in lipophilic environments. Such properties allow L-CRP for the reliable imaging of specific CTB activities in foam cells and atherosclerotic plaques while keeping in silence toward CTB in lipid-deficient environments, such as M1-type macrophages and LPS-induced inflammatory lesions. Moreover, the activatable PA signals of L-CRP exhibit a deeper tissue penetration ability (>1.0 cm) than current CTB probes based on near-infrared fluorescent imaging (∼0.3 cm), suitable for atherosclerosis imaging in living mice. In atherosclerotic mice, L-CRP dynamically reports intraplaque CTB levels, which is well-correlated with the plaque vulnerability characteristics such as fiber cap thickness, macrophage recruitment, and necrotic core size, thus enabling risk stratification of atherosclerotic mice complicated with pneumonia. Moreover, L-CRP successfully identifies atherosclerotic plaques in excised human artery tissues, promising for auxiliary diagnosis of plaque vulnerability in clinical application.

Model development of lattice-matched p-GaInP/i-GaAs/n-GaInP hetero-junction solar cell and its performance optimization

We report an analytical model for our proposed lattice-matched hetero-junction p-GaInP/i-GaAs/n-GaInP solar cell with the incorporation of AlInP cap layer and MgF2/TiO2 anti-reflection region supported by numerical data obtained using SENTAURUS TCAD. We investigate the impact of intrinsic layer thickness, cap layer thickness, compositional variation of gallium in GaInP alloy used in p- and n-regions of pin solar cell and also studied the effect of indium tin oxide (ITO) anode contact on photovoltaic performance of solar cell in terms of performance matrices i.e., open circuit voltage (Voc), short circuit current density (Jsc), fill-factor and power conversion efficiency (PCE). Also the performance of the proposed solar cell is optimized by judiciously choosing intrinsic layer thickness, and cap layer thickness. Our proposed device featuring 2.1-μm thick i-layer, 156-nm thick cap layer with Ga0.5In0·5P/GaAs active region yields a PCE of 19.89% which turns out to be 67% improvement as compared to the conventional solar cell enabling the proposed design attractive for photovoltaic applications.

Reproducibility of an artificial intelligence optical coherence tomography software for tissue characterization: Implications for the design of longitudinal studies

BackgroundTo assess the reproducibility of coronary tissue characterization by an Artificial Intelligence Optical Coherence Tomography software (OctPlus, Shanghai Pulse Medical Imaging Technology Inc.). Methods74 patients presenting with multivessel ST-segment elevation myocardial infarction (STEMI) underwent optical coherence tomography (OCT) of the infarct-related artery at the end of primary percutaneous coronary intervention (PPCI) and during staged PCI (SPCI) within 7 days thereafter in the MATRIX (Minimizing Adverse Hemorrhagic Events by Transradial Access Site and angioX) Treatment-Duration study (ClinicalTrials.gov, NCT01433627). OCT films were run through the OctPlus software. The same region of interest between either side of the stent and the first branch was identified on OCT films for each patient at PPCI and SPCI, thus generating 94 pairs of segments. 42 pairs of segments were re-analyzed for intra-software difference. Five plaque characteristics including cholesterol crystal, fibrous tissue, calcium, lipid, and macrophage content were analyzed for various parameters (span angle, thickness, and area). ResultsThere was no statistically significant inter-catheter (between PPCI and SPCI) or intra-software difference in the mean values of all the parameters. Inter-catheter correlation for area was best seen for calcification [intraclass correlation coefficient (ICC) 0.86], followed by fibrous tissue (ICC 0.87), lipid (ICC 0.62), and macrophage (ICC 0.43). Some of the inter-catheter relative differences for area measurements were large: calcification 9.75 %; cholesterol crystal 74.10 %; fibrous tissue 5.90 %; lipid 4.66 %; and macrophage 1.23 %. By the intra-software measurements, there was an excellent correlation (ICC > 0.9) for all tissue types. The relative differences for area measurements were: calcification 0.64 %; cholesterol crystal 5.34 %; fibrous tissue 0.19 %; lipid 1.07 %; and macrophage 0.60 %. Features of vulnerable plaque, minimum fibrous cap thickness and lipid area showed acceptable reproducibility. ConclusionThe present study demonstrates an overall good reproducibility of tissue characterization by the Artificial Intelligence Optical Coherence Tomography software. In future longitudinal studies, investigators may use discretion in selecting the imaging endpoints and sample size, accounting for the observed relative differences in this study.

Effect of diamond cap thickness on temperature distribution and thermal aberration of thin disk Nd:YAG laser crystal

To improve the heat dissipation performance of Nd:YAG lasers, sandwich-type Nd:YAG laser crystal with a diamond cap is analyzed by using a 2D numerical model, and the effect of the diamond cap thickness on the temperature distribution and thermal aberration is investigated. The simulation results reveal that the diamond cap with a thickness of 1 mm can reduce the maximum temperature inside the Nd:YAG to 309.7 K, which is 38 K lower than that of the laser crystal without a cap. Thermal aberration causes the optical path difference (OPD) inside laser crystal, and the total OPD of the Nd:YAG with the 1-mm-thickness diamond cap is lower compared to that of Nd:YAG without or with a 1-mm-thickness YAG cap. As the diamond cap thickness increases from 0.2 mm to 1 mm, the maximum temperature inside Nd:YAG decreases by 2.3 K and the near-axis OPD of the composite structure changes from negative to positive. Moreover, the spherical thermal aberration is described by the dioptric power and the absolute value of the dioptric power decreases with the increase of the diamond cap thickness. The dioptric power reaches zero at a diamond cap thickness of 0.59 mm, which means that a certain thickness of diamond cap can correct spherical thermal aberration. Therefore, to achieve better laser beam quality and higher output power, the optimal thickness of the diamond cap can be designed by considering the effects of temperature distribution and thermal aberration of the laser crystal.

Achieved low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio predicts the pathophysiological evolution of lipid-rich plaques in acute coronary syndromes: an optical coherence tomography study.

As a novel lipoprotein ratio, baseline low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (LHR) is closely related to the clinical outcomes of acute coronary syndromes (ACS) after percutaneous coronary intervention. However, the pathophysiological impact of achieved LHR (aLHR) on the evolution of non-culprit lipid-rich plaques has not been systematically explored. Between September 2013 and December 2018, ACS patients with both baseline and 1-year follow-up optical coherence tomography (OCT) examinations were included in current study. They were divided into two groups according to the median value of aLHR at 1 year. Overall, 132 patients with 215 lipid-rich plaques were enrolled, with a median aLHR: 1.62. There were thinner fibrous cap thickness (FCT) (133.3 [70.0-180.0] µm vs. 160.0 [100.0-208.3] µm, p = 0.025) and higher prevalence of thin-cap fibroatheroma (TCFA) (24 [22.4%] vs. 13 [12.0%], p = 0.044) and CLIMA-defined high-risk plaques (12 [11.2%] vs. 3[2.8%], p = 0.015) in the high aLHR group at 1 year. Compared with other serum lipid indexes, aLHR showed the best robust correlation with the evolution of plaque vulnerability in both unadjusted and adjusted analyses. Cut-off value of aLHR to predict the progression of maximal lipid arc and FCT was 1.51. In the adjusted model, aLHR ≥1.51 was an independent predictor of TCFA [odds ratio (OR): 3.008, 95% CI: 1.370 to 6.605, p = 0.006] at 1 year. aLHR correlates well with the evolution of lipid-rich plaques and vulnerable phenotypes at 1-year follow-up, which might be an important and convenient serum indicator in the secondary prevention of ACS.

Impact of the Electric Polarizability on the Transport and Collective Dynamics of Metallodielectric Janus Particles.

The objective of this article is to investigate how the electric polarizability manifests on the propulsion and collective dynamics of metallodielectric Janus particles by comparing the velocity spectra under rotating and nonrotating AC fields. Janus particles were fabricated by depositing sequential layers of titanium and SiO2 on spherical cores. Model systems of known polarizability were created by varying the thickness of titanium or by adjusting the concentration of electrolyte. We found that the spectra for propulsion velocity displayed features (amplitude and transition frequencies) that were closely matched in the electrorotation spectra. That is, the transition frequency from dielectric- to metal-side forward matched closely the peak in counterfield rotation, while the minima in propulsion velocity matched the transition frequency from counterfield to cofield rotation. Furthermore, based on electroorientation measurements for prolate Janus ellipsoids, we conclude that the propulsion velocity of spherical Janus particles reflects the real part of their polarizability. Solutions of the Poisson-Nernst-Planck equations confirm the thickness of the metal cap facilitates adjusting the behavior from metal- to dielectric-like. These traits translate into different collective behaviors, such as the ability to traverse or become part of a lattice of nonpatchy silica particles. Overall, these results provide experimental evidence to either challenge or refine existing electrokinetic models of propulsion.

NOX2 inhibition stabilizes vulnerable plaques by enhancing macrophage efferocytosis via MertK/PI3K/AKT pathway

NADPH oxidases 2 (NOX2) is the main source of ROS in macrophages, which plays a critical role in the formation of atherosclerosis. However, effects of NOX2 inhibition on established vulnerable plaques and the potential role involved remain unclear. The purpose of this study is to investigate the latent mechanism of NOX2-triggered vulnerable plaque development. We generated a vulnerable carotid plaque model induced by carotid branch ligation and renal artery constriction, combined with a high-fat diet in ApoE−/− mice. NOX2 specific inhibitor, GSK2795039 (10 mg/kg/day by intragastric administration for 8 weeks) significantly prevented vulnerable plaque, evaluated by micro-ultrasound imaging parameters. A profile of less intraplaque hemorrhage detection, increased collagen-lipid ratio, fibrous cap thickness and less necrotic core formation were also found in GSK2795039 treated group. Mechanistically, reduced 4-HNE, in situ lesional apoptosis and enhanced efferocytosis were involved in mice treated with NOX2 inhibitor. Further analysis in mouse macrophages confirmed the role of NOX2 inhibition in enhancing macrophage efferocytosis by regulating the MertK/PI3K/AKT pathway. In summary, our data defined previously few recognized roles of NOX2 in vulnerable plaque pathogenesis and an undescribed NOX2-ROS-MerTK axis acts involved in regulating macrophage efferocytosis in the formation of rupture-prone vulnerable plaques.

Effects of Lipid Lowering Therapies on Vulnerable Plaque Features: An Updated Narrative Review of the Literature.

The clinical evidence on the efficacy of lipid lowering therapy in patients with coronary artery disease (CAD) is unequivocally established. However, the effects of these therapies on plaque composition and stability are less clear. The use of intracoronary imaging (ICI) technologies has emerged as a complement to conventional angiography to further characterize plaque morphology and detect high-risk plaque features related to cardiovascular events. Along with clinical outcomes studies, parallel imaging trials employing serial evaluations with intravascular ultrasound (IVUS) have shown that pharmacological treatment has the capacity to either slow disease progression or promote plaque regression, depending on the degree of lipid lowering achieved. Subsequently, the introduction of high-intensity lipid lowering therapy led to much lower levels of low-density lipoprotein cholesterol (LDL-C) levels than achieved in the past, resulting in greater clinical benefit. However, the degree of atheroma regression showed in concomitant imaging trials appeared more modest as compared to the magnitude of clinical benefit accrued from high-intensity statin therapy. Recently, new randomized trials have investigated the additional effects of achieving very low levels of LDL-C on high-risk plaque features-such as fibrous cap thickness and large lipid accumulation-beyond its size. This paper provides an overview of the currently available evidence of the effects of moderate to high-intensity lipid lowering therapy on high-risk plaque features as assessed by different ICI modalities, reviews data supporting the use of these trials, and analyse the future perspectives in this field.

#3330 INFLAMMATION SECONDARY TO CHRONIC KIDNEY DISEASE AND PERITONEAL DIALYSIS ACCELERATES ATHEROSCLEROSIS IN A NEW MOUSE MODEL

Abstract Background and Aims Inflammation is an established contributor to accelerated atherosclerosis, which is highly prevalent in people with chronic kidney disease (CKD) and even more so in those treated with peritoneal dialysis (PD). We therefore hypothesised that PD-induced systemic inflammation is essential in the development of atherosclerosis. To study this we developed a novel mouse model of CKD and PD accelerated atherosclerosis. Method We performed a 5/6ths nephrectomy in ApoE deficient “black 6” mice, fed these mice a high-cholesterol diet (HCD), and intraperitoneally administered 3.86% Physioneal daily for 67 days. There were three groups of mice: control (HCD-only), CKD+HCD, and CKD+HCD+PD, with relevant shams. Tissues were harvested twelve weeks after the nephrectomy. Assessments of residual kidney function, atherosclerotic plaque pathology and immunology, and systemic immune responses were performed. Results Atherosclerotic plaque size in the aortic arch was larger in the PD group compared to the control, increasing from 83,779 μm2 ±18,430 to 109,973 μm2 ±25,602 (p = 0.0349), whilst plaque size was unchanged in the CKD group. In contrast, both the CKD and PD groups displayed altered plaque stability. There was less collagen in the plaque vs control, decreasing from 43.54% ±10.65 to 29.71% ±9.43 and 29.73% ±10.18 respectively. Additionally, fibrous cap thickness decreased in both groups vs control. The plaques from only the PD group showed infiltration by T-cells compared to control, with no changes in macrophage content in either the CKD or PD group. In the spleen in the CKD and PD groups, naïve CD4 cells increased and effector CD4 cells decreased compared to control, with the latter change also occurring in the circulation. Central memory CD4 cells, terminally differentiated Th1 cells, Th17 cells, and ‘vascular homing’ cells all increased in the PD group compared to control mice. These homing cells also increased in circulation. The PD group showed decreases in the spleen of regulatory T-cells, effector Th1 cells, and effector CD8 cells. Notably, all of these changes were absent from the mesenteric lymph node. There was a large drop in monocytes in the spleen and a loss of immature and mature dendritic cells in the PD group. Conclusion Combining CKD, a high-cholesterol diet, and exposure to PD fluids in ApoE−/-mice successfully generated a new model for cardiovascular disease in human PD patients. This new model is in a widespread and well-understood mouse line representative of human atherosclerosis. Here we demonstrate the pronounced effects of CKD and PD on the innate and adaptive immune response which increases atherosclerotic burden and leads to larger more vulnerable plaques

Controlling effects of cap rocks on the formation of deep geothermal resources

Cap rocks with high thermal insulation are important for deep geothermal systems at a depth of 3000‒6000 m. Based on the deep geothermal geological conditions in the Fujian-Guangdong-Hainan area of South China, this study established an ideal geological model of reservoir-cap rock assemblages and simulated the geothermal field distribution of cap rocks of different thicknesses and thermal conductivity. The simulation results show that the vertical geothermal temperature distribution in an uplifted area of a depression was present as inverted mirror reflections relative to the elevated area of the basement. Specifically, the isotherms above the elevated area are convex in shape, while those below the elevated area are concave. There is a temperature equilibrium line between the convex and concave isotherms. The heat flow moves from the depressed area to the uplifted area below the temperature equilibrium line and migrates in an opposite direction above the line. On this base, this study conducted the inversion of geothermal temperature fields in typical areas with thin, moderately thick, and thick cap rocks. The results indicate that, at the depth of 3000–6000 m, areas with thin cap rocks (igneous rock zone in the coastal area of Fujian) mainly host moderate- to low-temperature hydrothermal resources; areas with moderately thick cap rocks (Yuezhong Depression) have the geothermal temperature ranging between 100 °C and 200 °C and may develop moderate- to high-temperature hydrothermal resources and hot dry rocks (HDRs), with the former superimposing on the latter; and areas with thick cap rocks (onshore Beibuwan Basin) have a geothermal temperature of 120‒220 °C, and contains mainly moderate- to high-temperature hydrothermal resources and HDRs. Therefore, it is recommended that the evaluation, exploitation, and utilization of deep geothermal resources be carried out according to the burial depth of the temperature equilibrium line and the specific demand for geothermal resources.

Capping fiberbank sediments to reduce persistent organic pollutants (POPs) fluxes: A large-scale laboratory column experiment

Deposits of contaminated wood fiber waste (fiberbanks), originating from sawmills and pulp and paper industries, have been found in the aquatic environment in boreal countries. In-situ isolation capping has been proposed as a remediation solution because it has the potential to prevent dispersal of persistent organic pollutants (POPs) from this type of sediment. However, knowledge about the performance of such caps when placed on very soft (unconsolidated), gaseous organic rich sediment is scarce. We investigated the effectiveness of conventional in-situ capping to limit POPs fluxes to the water column from contaminated fibrous sediments that produce gas. A controlled, large-scale laboratory column (40 cm diameter, 2 m height) experiment was performed over 8 months to study changes in sediment-to-water fluxes of POPs and particle resuspension before and after capping the sediment with crushed stones (≥4 mm grain size). Two different cap thicknesses were tested (20 and 45 cm) on two types of fiberbank sediment with different fiber type composition. Results showed that capping fiberbank sediment with a 45 cm gravel cap reduced the sediment-to-water flux by 91–95% for p,p’-DDD, o,p’-DDD, by 39–82% for CB-101, CB-118, CB-138, CB-153, CB-180 and by 12–18% for HCB, whereas for less hydrophobic PCBs, capping was largely ineffective (i.e. CB-28 and CB-52). Although cap application caused particle resuspension, the long-term effect of the cap was reduced particle resuspension. On the other hand, substantial sediment consolidation released large volumes of contaminated pore water into the overlying water body. Importantly, both sediment types produced large amount of gas, observed as gas voids forming inside the sediment and gas ebullition events, which increased pore water advection and affected the structural integrity of the cap. This may limit the practical applicability of this method on fiberbank sediments.

Study on Radial Distribution of Fragments Velocity of D-shaped Fragmentation Warhead

For the asymmetric D-shaped fragmentation warhead with high charging coefficient and space efficiency, we simulate the driving process of fragments under typical eccentric initiation by using the fluid-structure interaction algorithm, and obtained the change rule of the fragment velocity radial distribution with the central angel, the thickness and material of the upper end cap. The results of numerical simulation show that the fragment velocity of D-shaped warhead increases gradually from the reverse to the forward direction, the velocity of fragment in forward direction increases by about 10% under single-point eccentric initiation compared with the cylindrical casing under center initiation, and the fragment velocity under double-point eccentric initiations is higher than single-point eccentric initiation; The initial velocity of the fragment has a positive correlation with the thickness and density parameters of the upper end cap; the mass of the warhead and the total kinetic energy of the fragments in the forward area increase with the increase of the central angle, but their ratio increases first and then decreases with the increase of the central angle. The results can be applied to structural optimization design and power evaluation of the warhead.

P62 SEASON VARIABILITY IN ATHEROSCLEROSIS COMPOSITION: INSIGHTS FROM 1848 NON–CULPRIT CORONARY PLAQUES

Abstract Background Several environmental and seasonal factors are thought to be crucial in the risk of acute coronary syndromes (ACS), including temperature, latitude, longitude, atmospheric air pressure, wind velocity and circadian period. However differences in coronary plaque composition according to season variation is still poorly understood. Purpose. Our study aims to analyse the characteristics of non–culprit coronary plaques in patients undergoing optical coherence tomography evaluation (OCT) evaluation of the left anterior descending artery. Methods We included 1848 non–culprit coronary plaques from 1003 patients of the CLIMA registry. The season of OCT pullback acquisition was collected for each patient. Results Overall, median age was 66 years (56–74), with 24.6% of women and 53.4% of ACS. At patient–level analysis, patients admitted in summer were less frequently affected by hypertension (59.8% vs 69.4% in autumn, 68.5% in winter and 72% in spring; p=0.027) and chronic kidney disease (14.8% vs 15.9% in autumn, 10.3% in winter and 19.4% in spring; p=0.037) in. At lesion–level analysis, similar values of fibrous cap thickness, maximum lipid arc, length of plaques and presence of macrophages were observed (Table 1). Summer plaques had a smaller minimum lumen area than spring plaques (5.7±3.1 vs 5.1±239; p=0.044) and also a less frequent superficial macrophage infiltration (23% vs 36.1% in autumn, 30.5% in winter and 30.6% in spring; p=0.030) and presence of cholesterol crystals (16.7% vs 23.8% in autumn, 28.4% in winter and 22.1% in spring; p=0.037 than three other season). Conclusions Coronary plaques during summer had less local sign of inflammation such superficial macrophage infiltration and cholesterol crystals. Further studies are needed to confirm these results and investigate clinical implications.

Passivation capping of InAs surface quantum dots by TMA/Al2O3: PL enhancement and blueshift suppression

Passivation capping that enhances the photoluminescence (PL) of molecular beam epitaxy (MBE)-grown InAs surface quantum dots (SQDs) is realized by ex situ low-temperature atomic layer deposition (ALD)-grown Al2O3. As the Al2O3 cap thickness increased from 2 to 30 nm, the PL intensity was enhanced by 2.7-fold and the blue shift was suppressed. This is in strong contrast to wet chemistry passivation and in situ GaAs capping by MBE, both of which resulted in significant PL blueshift, due to etching in the former, and In/Ga intermixing and strain in the latter. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) reveal that the Al2O3 cap layer mimics the shape of the underlying SQDs. The cross-sectional transmission electron microscopy (TEM) further reveals that the SQD size and shape remained unchanged after Al2O3 capping, which is in strong contrast to MBE-capping. The passivation mechanisms and native oxide reduction by trimethylaluminum (TMA), including self-clean-up reaction through ligand exchange, are discussed based on the results by x-ray photoelectron spectroscopy (XPS). A detailed comparison between Al2O3 and ZnO cap layers reveals the significance of the cap properties on the SQD size/shape and PL blueshift. While the size/shape of SQDs is preserved by Al2O3 capping, the apex is slightly removed by ZnO capping, resulting in a stronger PL blueshift compared to Al2O3.

Abstract 689: Loss of Smooth Muscle Cell Nogo-B Protects from Atherosclerosis Plaque Development

Background: Atherosclerosis, a major cause of cardiovascular diseases, is a lipid-driven inflammatory disease that occurs as fatty deposits, immune cells, calcium, and waste products accumulate on the walls of arteries over decades and often result in myocardial infarction or stroke. A member of the reticulon family of proteins, Nogo-B localizes in endothelial cells, vascular smooth muscle cells (VSMCs), and macrophages. Global and macrophage-specific Nogo-B deletion exacerbated atherogenesis by increasing lesion area and necrotic core size while decreasing cap thickness and collagen deposition. Our previous studies also suggest Nogo-B attenuates growth factor induced VSMC proliferation and neointimal formation after vascular injury. This study aims to elucidate the role of VSMC-specific Nogo-B in plaque development and stability in mice. Methods and Results: A murine atherosclerosis model was generated by specifically deleting Nogo-B in VSMCs of ApoE -/- mice with a Cre-recombinase system (Nogo-B iSMCKO ) and feeding a Western diet (1.25% cholesterol) for 14 weeks. VSMC-Nogo-B loss demonstrates a decreased necrotic core, minimized lesion size, and increased collagen content in aortic root lesions, all of which are indices of a more stable plaque phenotype. Nogo-B deletion in cultured VSMCs stimulated with β-CD cholesterol (20ug/mL) was performed to investigate phenotypic modulation and trans-differentiation in vitro . After cholesterol stimulation, expression of smooth muscle contractile genes was maintained in cells deficient in Nogo-B while decreasing in WT cells. Furthermore, VSMCs deficient in Nogo-B had decreased cholesterol uptake in cholesterol-loading experiments. Mechanistically, our results show Nogo-B modulates VSMC plasticity through transcription factor Krüppel-like factor 4. Conclusions: VSMC-specific Nogo-B deficiency attenuates atherogenesis and promotes stable plaque phenotypes. VSMC-specific Nogo-B deficiency may aid in the therapeutic intervention of atherosclerosis by improving plaque stability and patient prognosis.

Comparison between different approaches to evaluate fibrous cap thickness in sequential optical coherence tomography studies.

In this in-vivo human study we tested the reproducibility for optical coherence tomography (OCT) assessment of lumen area (LA) and plaque components measurements, such as lipid arc extension and fibrous cap thickness (FCt). We tested the variability of LA, lipid arc and FCt assessments in two repeated OCT pullbacks from the same diseased coronary segment matched using fiduciary anatomical landmarks. In particular, for the reliability of minimal FCt measurement we compared four different approaches based on continuous (longitudinal) or segmental (spot) individuation of smaller thickness: 1) comparison of single minimal FCt individuated alongside all plaque extension in the two pullbacks (Longitudinal (L)-spot minimal FCt value); 2) comparison of the mean FCt values of the plaque in the two pullbacks (L-plot mean FCt value); 3) comparison between the single minimal FCt value obtained in the first pullback and the single FCt obtained in the matched CS of second pullback (L-spot CS matched FCt value); 4) comparison of measurements obtained by visual selection of CS with minimal FCt s in the two pullbacks (single-spot minimal FCt value). From the paired analyses of 20 non culprit lesions (accounting for a total of 387 matched CS), we found a suboptimal in-segment correlation for LA (Intra-Class Coefficient [ICC] 0.731), but a good in-segment correlation for lipid arc (ICC 0.963). Regarding FCt measurement, a high reproducibility was obtained applying continuous assessment; in particular, the best correlation was observed with L-spot minimal FCt value and the L-plot mean FCt (ICC 0.893 and 0.952, respectively) with small inter-pullback differences (confidence intervals less than 0.04 mm). In this methodological study we observed a good reproducibility for quantitative plaque measurements with OCT confirming its reliability for serial assessment. In particular, longitudinal measurement in multiple adjacent frames seems to be the more accurate and reproducible approach for sequential FCt assessment.