目的 研究低强度脉冲超声波(LIPUS)对培养成肌细胞增殖分化的影响,探讨其治疗效应的细胞分子机制.方法 建立小鼠骨骼肌成肌细胞体外培养模型,将培养成肌细胞随机分增殖超声组、分化超声组、增殖对照组和分化对照组.增殖超声组和分化超声组均采用超声频率为1.5 MHz,平均强度为30 mW/cm2的低强度脉冲超声波辐射,每次20 min,每日1次,增殖超声组连续处理6d,分化超声组连续处理4d.增殖超声组与增殖对照组采用流式细胞仪进行细胞增殖动力学检测,免疫荧光染色检测成肌细胞生长因子MyoD、血红素加氧酶-1(HO-1)的表达,并对分化超声组与分化对照组进行肌球蛋白重链(MHC)染色和成肌细胞融合指数分析.结果 增殖超声组成肌细胞进入活性细胞周期G2/M与S期细胞比例和增殖指数(PI)分别为(19.30±5.14)％,(37.00±8.72)％和(47.93±0.87)％,与增殖对照组的(10.33±1.53)％,(25.00±4.36)％和(38.66 ±0.67)％比较,差异具有统计学意义(P＜0.05)；增殖超声组HO-1荧光染色阳性比例和平均荧光强度分别为(82.03 ±5.14)％和(152.02±4.76)％,与对照组的(60.01±3.22)％和(138.70±5.08)％比较,差异具有统计学意义(P＜0.05)；分化超声组成肌细胞融合指数(18.73 ±6.81)％,与分化对照组的(37.52±11.23)％比较,差异有统计学意义(P＜0.05).结论 低强度脉冲超声波促进成肌细胞的增殖,抑制其分化,且不改变其肌原属性,血红素加氧酶-1参与该调控过程.

Objective To study in vitro the effects of low-intensity pulsed ultrasound (LIPUS) on the proliferation and differentiation of cultured myoblasts,and to explore the cellular and molecular mechanisms behind any therapeutic effect of LIPUS.Methods Myoblasts were isolated from the skeletal muscles of mice and cultured in vitro.Treatment and control groups of proliferating and differentiating myoblasts were defined.The treatment groups were exposed to LIPUS at 1.5 MHz and a spatial and temporal average intensity of 30 mW/cm2,for 20 min daily,the proliferation group for 6 consecutive days and the differentiation group for 4 consecutive days.The cell proliferation kinetics of the proliferation group were analyzed using flow cytometry.The expression of myogenic regulation factor MyoD and heme oxygenase-1 (HO-1) in the proliferation group,and of myosin heavy chain (MHC) in the differentiation group were examined by immunofluorescent staining.Myoblast fusion indexes were analyzed.Results In the

目的将超声波、磁场引入到微电铸过程中,改善电沉积镍晶微构件的表面性能。方法改变电流密度、脉冲占空比、超声波功率、磁场强度的方向和强度,进行电沉积镍晶微铸件,分析这些工艺参数对微铸件表面形貌和显微硬度的影响。结果微铸件的显微硬度随磁场强度的增大而显著提高,随着阴极电流密度、超声波功率及脉冲占空比的增大呈现出先升高、后下降的规律,其中脉冲占空比对电铸层显微硬度的影响较弱。优选的工艺参数为:垂直磁场强度0.8 T,阴极电流密度2 A/dm2,超声波功率240W,脉冲占空比20%。结论引入超声波和磁场后可优化电沉积环境,细化电铸层晶粒尺寸,改善电铸层微观形貌,提高微铸件显微硬度。

Objective In order to improve the surface properties of electro-deposited nickel micro-electroforming parts, ultrason-ic and magnetic fields were introduced into the micro electroforming process. Methods Current intensity, pulse duty cycle, ultra-sonic power, direction and intensity of magnetic field strength were altered during the electro-deposition of nickel micro-electrofor-ming parts, and the effects of the above parameters on the performance of the surface morphology and microhardness of the micro-electroforming parts were analyzed. Results The micro-hardness of the micro-casting part increased significantly along with the in-crease of the magnetic field intensity, while first increased and then decreased along with the increasing current intensity, pulse du-ty cycle and ultrasonic power, among which the pulse duty cycle had weaker effect on the micro-hardness as compared to the other parameters. The optimized parameters were: vertical magnetic field intensity 0. 8 T, c