Biomechanical characterization of the Junzuki karate punch: indexes of performance

The aims of this study were: (i) to determine kinematic, kinetic, and electromyographic characteristics of Junzuki karate punch in professional karate athletes; (ii) to identify biomechanical parameters that correlate with punch force and lead to a higher punching performance; (iii) to verify the presence of muscle co-activation in the upper limb, trunk, and lower limb muscles. Data were collected from nine experienced karatekas from the Accademia Italiana Karate e Arti Marziali during the execution of the specific punch. Mean punch forces (181.2?N) delivered to the target, the range of motion of both right and left knees (1.13 and 0.82?rad) and right elbow (1.49?rad) joints, and the angles at impact (knee: 0.81 and 0.91?rad; elbow: 1.19?rad) in the sagittal plane were computed. Furthermore, the trunk rotational angular acceleration (63.1?rad^?s^?2), force related to the lower limbs (550.2 and 425.1?N), and co-activation index for the upper limb (36.1% and 34.7%), trunk (24.5% and 16%), and lower limbs (16.0% and 16.1%) muscles were evaluated bilaterally. Significant positive correlations were found between the punch force and both right and left knee flexion at the instant of impact and right and left leg force. Significant negative correlation was found between the punch force and maximum trunk angular acceleration. Significant differences (p?=?.03) in the co-activation index among the upper limb, trunk, and lower limbs muscles highlighted a rostro-caudal gradient on both body sides. This research could be of use to performers and coaches when considering training preparations.     

Development of a rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase-peroxidase enzymes

A rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase and peroxidase enzymes has been developed it takes only 11/2 minutes of time and validity of the method has been discussed.     

CHEMICAL KINETICS ON FRACTAL SURFACE

1Intr0ducti0nThekineticsofaheter0geneouscatalyticreactionisdeterminednotonlybythedetails0fthechemistryinvolved,butals0bythedetailsofthegeometryofthecatalyticsurfaceonwhichthecatalyticreactiontakesplace'.However,thegeometriesofcatalystsareoftenfrac-turedandirregular.Becauseofthelackofaneffectivemathematicaltoolt0describethedi-versityofthegeometries,the0riesofthecatalytickineticstreatthecatalyticsurfaceasanide-alplane.Asaresult,thereareconsiderablediscrepanciesbetweenthetheoreticalresultsandthee…     

谈波动中的能量

本采用波动方程及简单物理模型为分析方法，对一列横波上处在平衡位置的某一质点的机械能进行分析，对波动中点的能量变化进行了讨论，从而更深刻理解了“波是传播能量的一种方式”这句话的意义。     

铁饼技术教法研究

对新设计的教法,与常规传统教法进行实验,通过12学时6次课教学后,实验组学习成绩明显优于对照组成绩,结果证明,新设计的教学方法是可行的。     

磺化麦草碱木质素热分析动力学研究

为研究磺化碱木质素在高温条件下的热稳定性能,实验采用热重－红外分析(TG-IR)和差示扫描量热分析(DSC) 研究了磺化麦草碱木质素在非氧状态下热分解反应的动力学过程。利用多升温速率法Kissingr法和Ozawa法,分别计算了磺化麦草碱木质素热动力学方程中的表观活化能(Ｅ)和频率因子lnA,分别为118.3 kJ•mol-1、121.46 kJ•mol-1;20.40min-1、15.92min-1;利用Kissingr法计算了热动力学方程的反应级数是1.8。     

化学反应级数的判断方法

反应级数是化学动力学中的一个重要的基本概念,本文介绍了判断化学反应级数的几种方法:尝试法、微分法、图解法、半衰期法和反应速度常数单位法。     

亚硝酸盐催化动力学光度法在环境分析中实际应用的研究进展

本文评述了亚硝酸盐催化动力学光度法在环境分析中实际应用的研究发展状况 ,新近研究成果 ,以及相应光度分析方法的检出限和测定范围及干扰等     

催化动力学光度法测定痕量盐酸羟胺

研究发现在磷酸介质中,盐酸羟胺对溴酸钾氧化溴甲酚紫具有明显的催化作用,建立了一种测定痕量盐酸羟胺的新方法．其测定范围为００４～０５６μｇ／ｍｌ盐酸羟胺,检测限为００２μｇ／ｍｌ,用于化学试剂中盐酸羟胺的测定,获得了满意的结果     

糖尿病与胃轻瘫的关系

介绍了糖尿病与胃轻瘫的关系。糖尿病胃轻瘫的发病机理可能与糖尿病植物神经病变、平滑肌变性、高血糖等有关。诊断胃排空时间的方法有Ｘ线监视、胃肠电分析、Ｂ型超声及核素标记的试餐（金标准）。采用促胃动力药物如胃复安、多潘立酮、西沙比利、红霉素入Ｒｅｎｚａｐｒｉｄｅ对糖尿病胃轻瘫有一定的疗效。一旦被诊断为糖尿病胃轻瘫,宜及早使用促胃动力药,可改善糖尿病胃轻瘫的大部分症状和体征。