Adaptation of healthy mastication to factors pertaining to the individual or to the food

Mastication is a physiological process controlled by the central nervous system and modulated by inputs from the mouth. Both the intrinsic characteristics of the subject and the extrinsic characteristics of the chewed food are responsible for variations of the masticatory function. Age, gender and dental state constitute the most studied intrinsic factors whereas hardness, rheological characteristics such as plasticity or elasticity, and food size are the better known extrinsic factors. These factors cause physiological adaptations which can occur during individual cycles or the whole sequence of mastication. Electromyographic and jaw movements (kinematic) recordings are commonly used to study mastication, from which, several variables can be measured. Vertical and lateral amplitudes and, velocities of jaw movements, are only given by kinematic recordings. Bioelectrical activities per cycle or per sequence are closely linked to masticatory forces and are measured from electromyographic recordings. Number of cycles, sequence duration and masticatory frequency can be measured from both types of recordings. The objective of this review is to provide an overview of the variations of the measured masticatory variables that occur when mastication adapts to changes in characteristics of the individual or the food.     

氧驱动雾化吸入补钾纠正低钾血症的疗效观察与护理

目的探讨氧驱动雾化吸入补钾纠正低钾血症的临床疗效与护理。方法将25例低钾血症的患者随机分为实验组和对照组，每组各25例，分别用氧驱动雾化吸入和静脉滴注。结果两组在提高血钾浓度无差异。结论应用氧驱动雾化的方法给低血钾患者进行补钾，是一种较理想的方法，具有操作简单、患者易于接受，符合消毒隔离原则。值得临床推广应用。