Red Blood Cell Distribution Width as a Predictive Marker for Coronary Artery Lesions in Patients with Kawasaki Disease.

This study aimed to investigate the association between red blood cell distribution width (RDW) and the risk of coronary artery lesions (CALs) in patients with Kawasaki disease (KD). A total of 1355 patients who met the diagnostic criteria for KD were reviewed between January 2018 and December 2019, including 636 patients with CALs and 719 patients without CALs. Blood samples for RDW were obtained at admission (before intravenous immunoglobulin treatment). A logistic regression analysis was performed, and a receiver operating characteristic curve was constructed to determine the prognostic value of RDW standard deviation (RDW-SD) and RDW coefficient of variation (RDW-CV). The study was registered at www.chictr.org.cn , No.: ChiCTR 2000040980. The results showed that RDW-SD increased in patients with complete KD and CALs compared with patients with complete KD without CALs (39 fL vs. 38 fL, respectively; p = 0.000). RDW-CV in patients with complete KD and CALs was significantly higher compared with patients with completed KD without CALs (p = 0.000). Further multivariate logistic regression analysis revealed that RDW-SD was an independent marker of CALs in patients with complete KD (p = 0.001), but no association was found between RDW-CV and CALs. The area under the curve of RDW-SD for predicting CALs in patients with complete KD was 0.606 (95% confidence interval 0.572-0.640; p = 0.000) with a sensitivity and specificity of 61% and 55%, respectively, when the optimal cut-off value of RDW-SD was 38.5 fL. RDW-CV increased in patients with incomplete KD and CALs compared with patients without CALs (13.55% vs 13.3%, respectively; p = 0.004), and multivariate logistic regression analysis revealed that RDW-CV was an independent marker of CALs in patients with incomplete KD (p = 0.021). The area under the curve of RDW-CV for predicting CALs in patients with incomplete KD was 0.597 (95% confidence interval 0.532-0.661; p = 0.004) with a sensitivity and specificity of 40% and 77%, respectively, when the optimal cut-off value of RDW-SD was 13.85%. Conclusion: RDW can be used as an independent predictive marker of CALs in patients with KD, but the type of KD should be considered. RDW-SD was an independent marker of CALs in patients with complete KD, while RDW-CV was a predictor of incomplete KD.

Nanoparticle Capture During Directional Solidification of Nano-Sized SiC Particle-Reinforced AZ91D Composites.

The capture/push behavior of a particle in front of a solidification interface was analyzed theoretically and experimentally in this work. Van der Waals force, viscous force, and force due to interfacial energy played important roles in the particle capture/push process. Directional solidification experiments were conducted with nano-sized SiC particle-reinforced AZ91D composites to observe the distribution of nanoparticles in different solidification morphologies under varied cooling rates. When the composite solidified with plane manner, the nanoparticles could be captured by the solidification front and distributed uniformly in the matrix. When solidified with columnar or equiaxial manners, the nanoparticles could be captured by the solidification front but distributed uniformly only in the grain boundary as a result of the difference in interfacial energy and wettability between SiC/α-Mg and SiC/eutectic phase. Theoretical prediction of particle capture was in agreement with the experiment results.

Effects of annealing on the structure and magnetic properties of Fe80B20 magnetostrictive fibers.

BACKGROUND: Fe80B20 amorphous alloys exhibit excellent soft magnetic properties, high abrasive resistance and outstanding corrosion resistance. In this work, Fe80B20 amorphous micro-fibers with HC of 3.33 Oe were firstly fabricated and the effects of annealing temperature on the structure and magnetic properties of the fibers were investigated. METHODS: In this study, Fe80B20 amorphous fibers were prepared by the single roller melt-spinning method. The structures of as-spun and annealed fibers were investigated by X-ray diffractometer (XRD) (PANalytical X,Pert Power) using Cu Kα radiation. The morphology of the fibers was observed by scanning electron microscopy (SEM) (HITACHI-S4800). Differential scanning calorimetry (DSC) measurements of the fibers were performed on Mettler Toledo TGA/DSC1 device under N2 protection. Vibrating sample magnetometer (VSM, Versalab) was used to examine the magnetic properties of the fibers. The resonance behavior of the fibers was characterized by an impedance analyzer (Agilent 4294A) with a home-made copper coil. RESULTS: The X-ray diffusion (XRD) patterns show that the fibers remain amorphous structure until the annealing temperature reaches 500°C. The differential scanning calorimetry (DSC) results show that the crystallization temperature of the fibers is 449°C. The crystallization activation energy is calculated to be 221 kJ/mol using Kissinger formula. The scanning electron microscopy (SEM) images show that a few dendrites appear at the fiber surface after annealing. The result indicates that the coercivity HC (//) and HC (⊥) slightly increases with increasing annealing temperature until 400°C, and then dramatically increases with further increasing annealing temperature which is due to significant increase in magneto-crystalline anisotropy and magneto-elastic anisotropy. The Q value firstly increases slightly when the annealing temperature rises from room temperature (RT) to 300°C, then decreases until 400°C. Eventually, the value of Q increases to ~2000 at annealing temperature of 500°C. CONCLUSIONS: In this study, Fe80B20 amorphous fibers with the diameter of 60 µm were prepared by the single roller melt-spinning method and annealed at 200°C, 300°C, 400°C, and 500°C, respectively. XRD results indicate that the fiber structure remains amorphous when the annealing temperature is below 400°C. α-Fe phase and Fe3B phase appear when the annealing temperature rises to 500°C, which is above the crystallization temperature of 449°C. The recrystallization activation energy is calculated to be 221 kJ/mol. The coercivity increases with increasing annealing temperature, which attributes to the increase of total anisotropy. All the as-spun and annealed fibers exhibit good resonance behavior for magnetostrictive sensors.