Morphological and stress vulnerability indices for human coronary plaques and their correlations with cap thickness and lipid percent: An IVUS-based fluid-structure interaction multi-patient study

Plaque vulnerability, defined as the likelihood that a plaque would rupture, is difficult to quantify due to lack of in vivo plaque rupture data. Morphological and stress-based plaque vulnerability indices were introduced as alternatives to obtain quantitative vulnerability assessment. Correlations between these indices and key plaque features were investigated. In vivo intravascular ultrasound (IVUS) data were acquired from 14 patients and IVUS-based 3D fluid-structure interaction (FSI) coronary plaque models with cyclic bending were constructed to obtain plaque wall stress/strain and flow shear stress for analysis. For the 617 slices from the 14 patients, lipid percentage, min cap thickness, critical plaque wall stress (CPWS), strain (CPWSn) and flow shear stress (CFSS) were recorded, and cap index, lipid index and morphological index were assigned to each slice using methods consistent with American Heart Association (AHA) plaque classification schemes. A stress index was introduced based on CPWS. Linear Mixed-Effects (LME) models were used to analyze the correlations between the mechanical and morphological indices and key morphological factors associated with plaque rupture. Our results indicated that for all 617 slices, CPWS correlated with min cap thickness, cap index, morphological index with r = -0.6414, 0.7852, and 0.7411 respectively (p<0.0001). The correlation between CPWS and lipid percentage, lipid index were weaker (r = 0.2445, r = 0.2338, p<0.0001). Stress index correlated with cap index, lipid index, morphological index positively with r = 0.8185, 0.3067, and 0.7715, respectively, all with p<0.0001. For all 617 slices, the stress index has 66.77% agreement with morphological index. Morphological and stress indices may serve as quantitative plaque vulnerability assessment supported by their strong correlations with morphological features associated with plaque rupture. Differences between the two indices may lead to better plaque assessment schemes when both indices were jointly used with further validations from clinical studies

Quantification of patient-specific coronary material properties and their correlations with plaque morphological characteristics: An in vivo IVUS study

BACKGROUND: A method using in vivo Cine IVUS and VH-IVUS data has been proposed to quantify material properties of coronary plaques. However, correlations between plaque morphological characteristics and mechanical properties have not been studied in vivo. METHOD: In vivo Cine IVUS and VH-IVUS data were acquired at 32 plaque cross-sections from 19 patients. Six morphological factors were extracted for each plaque. These samples were categorized into healthy vessel, fibrous plaque, lipid-rich plaque and calcified plaque for comparisons. Three-dimensional thin-slice models were constructed using VH-IVUS data to quantify in vivo plaque material properties following a finite element updating approach by matching Cine IVUS data. Effective Young\u27s moduli were calculated to represent plaque stiffness for easy comparison. Spearman\u27s rank correlation analysis was performed to identify correlations between plaque stiffness and morphological factor. Kruskal-Wallis test with Bonferroni correction was used to determine whether significant differences in plaque stiffness exist among four plaque groups. RESULT: Our results show that lumen circumference change has a significantly negative correlation with plaque stiffness (r = -0.7807, p = 0.0001). Plaque burden and calcification percent also had significant positive correlations with plaque stiffness (r = 0.5105, p \u3c 0.0272 and r = 0.5312, p \u3c 0.0193) respectively. Among the four categorized groups, calcified plaques had highest stiffness while healthy segments had the lowest. CONCLUSION: There is a close link between plaque morphological characteristics and mechanical properties in vivo. Plaque stiffness tends to be higher as coronary atherosclerosis advances, indicating the potential to assess plaque mechanical properties in vivo based on plaque compositions

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p

Analyze why Chinese students find it difficult to learn the Italian language from the perspective of information theory.

reservedQuesto articolo parte dalla prospettiva della teoria dell'informazione e utilizza concetti come l'entropia dell'informazione, la ridondanza dell'informazione e l'ipotesi UID per spiegare perché gli studenti cinesi incontrano difficoltà nell'apprendimento della lingua italiana. Sulla base di questi problemi, vengono proposti alcuni suggerimenti.This article starts from the perspective of information theory and uses concepts such as information entropy, information redundancy, and the UID hypothesis to explain why Chinese students encounter difficulties in learning the Italian language. Based on these issues, some suggestions are proposed

Towards Accurate Low Bit-Width Quantization with Multiple Phase Adaptations

Low bit-width model quantization is highly desirable when deploying a deep neural network on mobile and edge devices. Quantization is an effective way to reduce the model size with low bit-width weight representation. However, the unacceptable accuracy drop hinders the development of this approach. One possible reason for this is that the weights in quantization intervals are directly assigned to the center. At the same time, some quantization applications are limited by the various of different network models. Accordingly, in this paper, we propose Multiple Phase Adaptations (MPA), a framework designed to address these two problems. Firstly, weights in the target interval are assigned to center by gradually spreading the quantization range. During the MPA process, the accuracy drop can be compensated for the unquantized parts. Moreover, as MPA does not introduce hyperparameters that depend on different models or bit-width, the framework can be conveniently applied to various models. Extensive experiments demonstrate that MPA achieves higher accuracy than most existing methods on classification tasks for AlexNet, VGG-16 and ResNet

Lentivirus-TAZ Administration Alleviates Osteoporotic Phenotypes in the Femoral Neck of Ovariectomized Rats

Background: Osteoporosis is characterized by impairment of bone mass, strength, and microarchitecture, leading to the susceptibility to fragility fractures, especially in femoral neck region. Transcriptional coactivator with PDZ-binding motif (TAZ) facilitates osteogenesis while suppressing adipogenesis via regulation of transcriptional activities of runt-related transcription factor 2 and peroxisome proliferator-activated receptor &#947;. Here, we validated the role of TAZ in vivo using an ovariectomized (OVX) rat model of osteoporosis. Methods: Serum alkaline phosphatase, triglyceride, cholesterol and urinary hydroxyproline were measured on an automatic analyzer using diagnostic reagent kits. Serum OCN and C-terminal cross-linked telopeptides of type I collagen were measured using ELISA. Bone mineral density was measured using dual-energy X-ray scanner. Mechanical parameters were detected by three-point bending assays. Bone volume per tissue volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. No), and trabecular separation (Tb. Sp) were measured by MicroCT. The mRNA and protein levels were quantified by Realtime PCR and Western Blotting respectively. Results: After injections of lentivirus overexpressing TAZ into the femoral neck region, bone mineral density, ultimate force, stiffness, BV/TV, Tb. Th, and Tb. No were significantly increased, whereas Tb. Sp was dramatically decreased. In the TAZ-overexpression region in the femoral neck of OVX rats, the mRNA levels of Runx2 and osteocalcin were obviously elevated, whereas that of PPAR&#947; and adipocyte protein 2 were downregulated. Conclusion: Lentivirus-mediated TAZ gene therapy alleviated the osteoporotic phenotypes in the femoral neck of OVX rats, providing an alternative strategy for the treatment of postmenopausal osteoporosis and prevention of osteoporotic fracture

Effect on Fine Particles Output Characteristics of Ceramic Ball Grinding

Steel balls as traditional grinding media are prone to excessive fines generation and high energy consumption. Therefore, in light of this problem, the authors investigated another media—ceramic balls based on the output characteristics of fine particles. This study discusses the effect of ceramic balls on the change of the particle size distribution, zero-order output characteristics, micro-strain, and collision energy in ground products. The results showed that for −10 μm particle size, ceramic balls have a smaller production rate than steel balls. In addition, when the filling rate of ceramic balls is 40%, the yield of −10 μm is reduced compared to steel balls. Therefore, ceramic balls greatly reduced the overgeneration of fines. Additionally, the micro-strain rate of ceramic ball grinding with time is 67% lower than that of steel ball grinding. Furthermore, ceramic balls cannot only mitigate excessive fines generation but also effectively reduce energy consumption