Current Issue : July - September Volume : 2017 Issue Number : 3 Articles : 5 Articles
In this study, we introduce novel method of flow cytometry for cell detection based on\nimpedance measurements. The state of the art method for impedance flow cytometry detection\nutilizes an embedded electrode in the microfluidic to perform measurement of electrical impedance\nof the presence of cells at the sensing area. Nonetheless, this method requires an expensive and\ncomplicated electrode fabrication process. Furthermore, reuse of the fabricated electrode also requires\nan intensive and tedious cleaning process. Due to that, we present a microfluidic device with\nintegrated microneedles. The two microneedles are placed at the half height of the microchannel\nfor cell detection and electrical measurement. A commercially-available Tungsten needle was\nutilized for the microneedles. The microneedles are easily removed from the disposable PDMS\n(Polydimethylsiloxane) microchannel and can be reused with a simple cleaning process, such as\nwashing by ultrasonic cleaning. Although this device was low cost, it preserves the core functionality\nof the sensor, which is capable of detecting passing cells at the sensing area. Therefore, this device is\nsuitable for low-cost medical and food safety screening and testing process in developing countries....
Background: Taking a bath sometimes poses a risk for subjects with chronic cardiopulmonary\ndisorders, due to the thermal effect and water pressure on his/her body.\nThe ECG measurement would be helpful for the early recognition of abnormal cardiac\nbeats and respiratory conditions. This paper describes a new attempt to improve on\nprevious bathtub ECG measurement techniques that had electrodes placed inside the\nbathtub that were intrusive to the subjectsâ�� bathing experience. This study is concerned\nwith the initial development of a method to measure an electrocardiogram (ECG)\nthrough tap water without conscious awareness of the presence of electrodes that are\nplaced outside the bathtub wall.\nMethods: A configuration of capacitive coupling electrodes placed outside the bathtub\nwas designed so that the electrodes could be hidden. The capacitive coupling was\nmade from the electrodes to the water through the bathtub wall. Two electrodes with\nan active shielding amplifier covered further by an electromagnetic shield were fixed\nto the outside surface of the bathtub wall, near the batherâ��s right scapula and left foot.\nThe potential difference between these two electrodes, similar to the bipolar lead-II\nECG, was amplified to obtain raw signals inclusive of ECG/QRS components. Respiration\nintervals were also derived from ECG/RR intervals. Comparison experiments between\nthis bathtub method and conventional direct methods with spot-electrodes and a\nchest-band sensor were made using 10 healthy male volunteers (22.2 �± 0.98 years).\nResults: The ECG signal was detectable through tap water as well as water with differing\nconductivity resulting from mixing bathwater additives with the water. ECG signals\nand respiration curves derived from ECG/RR intervals were successfully obtained in all\nsubjects. The intervals of the ECG/RR and respiration obtained by the bathtub system\nand by the direct method were respectively agreed well with each other.\nConclusion: The ECG signal, in particular ECG/QRS components, were successfully\ndetected utilizing capacitive coupling electrodes placed outside the bathtub wall. Also,\nthe ECG/RR and respiration intervals were determined with reasonable accuracy as\ncompared with the conventional direct methods....
Athletes and military recruits are often afflicted by stress fractures. Rigorous\ntraining programs consisting of increased repetitive mechanical loading may\ncontribute to the high incidence of tibia stress fracture in the athletic and army\npopulations. The purpose of this study was to assess the effect of incremented\nheight on tibia bone strains and strain rates during landing. Seven\nhealthy college males performed drop-landing tasks from 26 cm, 39 cm, and\n52 cm, respectively. Tibia bone strains and strain rates were obtained through\nsubject-specific multi-body dynamic computer simulations and finite element\nanalyses. One-way repeated measures ANOVAs were conducted. Both 39 cm\nand 52 cm conditions resulted in larger tibia bone strains and strain rates than\nthe 26 cm condition. The 52 cm condition also resulted in greater bone strains\nand strain rates than the 39 cm condition. A dose-response relationship exists\nbetween incremented landing height and bone strains and strain rates. Activities\nconsisting of high impact landings are associated with increased risk of\ndeveloping tibia stress fracture. When designing training programs involved\nhigh impact activities, athletes and military recruits should consider the effect\nof impact loading on tibia bone health and giving enough time for bones to\nadapt to new trainings....
Background and aims: The existence of non-excitable cells in the myocardium leads\nto the increasing conduction non-uniformity and decreasing myocardial electrical\nconductivity. Slowed myocardial conduction velocity (MCV) believed to enhance the\nprobability of cardiac arryhthmia and alter the cardiac mechanical pumping efficacy,\neven in sinus rhythm. Though several studies on the correlation between MCV and\ncardiac electrical instabilities exist, there has been no study concerning correlation or\ncausality between MCV and cardiac mechanical pumping efficacy, due to the limitation\nin clinical methods to document and evaluate cardiac mechanical responses directly.\nThe goal of this study was to examine quantitatively the cardiac pumping efficacy\nunder various MCV conditions using three-dimensional (3D) electromechanical model\nof canine�s failing ventricle.\nMethods: The electromechanical model used in this study composed of the electrical\nmodel coupled with the mechanical contraction model along with a lumped model of\nthe circulatory system. The electrical model consisted of 241,725 nodes and 1,298,751\nelements of tetrahedral mesh, whereas the mechanical model consisted of 356 nodes\nand 172 elements of hexahedral mesh with Hermite basis. First, we performed the\nelectrical simulation for five different MCV conditions, from 30 to 70 cm/s with 10 cm/s\ninterval during sinus pacing. Then, we compared the cardiac electrical and mechanical\nresponses of each MCV condition, such as the electrical activation time (EAT), pressure,\nvolume, and energy consumption of the myocardium. The energy consumption of\nthe myocardium was calculated by integrating ATP consumption rate of each node in\nmyofilament model.\nResults: The result showed that under higher MCV conditions, the EAT, energy consumption,\nend diastolic and systolic volume are gradually decreased. Meanwhile, the\nsystolic pressure, stroke volume, stroke work, and stroke work to ATP are increased as\nthe MCV values increased. The cardiac functions and performances are more efficient\nunder higher MCV conditions by consuming smaller energy (ATP) while carrying more\nworks.\nConclusion: In conclusion, this study reveals that MCV has strong correlation with the\ncardiac pumping efficacy. The obtained results provide useful information to estimate\nthe effect of MCV on the electro-physiology and hemodynamic responses of the ventricle\nand can be used for further study about arrhythmogeneis and heart failure....
Quantitative evaluation of the hemiparesis status for a poststroke patient is still challenging. This study aims to measure and\ninvestigate the dynamic muscle behavior in poststroke hemiparetic gait using ultrasonography. Twelve hemiparetic patients\nwalked on a treadmill, and EMG, joint angle, and ultrasonography were simultaneously recorded for the gastrocnemius medialis\nmuscle. Pennation angle was automatically extracted from ultrasonography using a tracking algorithm reported previously. The\ncharacteristics ofEMG, joint angle, and pennation angle in gait cyclewere calculated for both (affected and unaffected) sides of lower\nlimbs.The results suggest that pennation angle could work as an importantmorphological index to continuousmuscle contraction.\nThe change pattern of pennation angle between the affected and unaffected sides is different from that of EMG. These findings\nindicate that morphological parameter extracted from ultrasonography can provide different information from that provided by\nEMG for hemiparetic gait....
Loading....