Variable Membrane Dielectric Polarization Characteristic in Individual Live Cells.

Investigation of the dielectric properties of cell membranes plays an important role in understanding the biological activities that sustain cellular life and realize cellular functionalities. Herein, the variable dielectric polarization characteristics of cell membranes are reported. In controlling the dielectric polarization of a cell using dielectrophoresis force spectroscopy, different cellular crossover frequencies were observed by modulating both the direction and sweep rate of the frequency. The crossover frequencies were used for the extraction of the variable capacitance, which is involved in the dielectric polarization across the cell membranes. In addition, this variable phenomenon was investigated by examining cells whose membranes were cholesterol-depleted with methyl-ß-cyclodextrin, which verified a strong correlation between the variable dielectric polarization characteristics and membrane composition changes. This study presented the dielectric polarization properties in live cells' membranes that can be modified by the regulation of external stimuli and provided a powerful platform to explore cellular membrane dielectric polarization.

Automated Dielectrophoretic Tweezers-Based Force Spectroscopy System in a Microfluidic Device.

We reported an automated dielectrophoretic (DEP) tweezers-based force spectroscopy system to examine intermolecular weak binding interactions, which consists of three components: (1) interdigitated electrodes and micro-sized polystyrene particles used as DEP tweezers and probes inside a microfluidic device, along with an arbitrary function generator connected to a high voltage amplifier; (2) microscopy hooked up to a high-speed charge coupled device (CCD) camera with an image acquisition device; and (3) a computer aid control system based on the LabVIEW program. Using this automated system, we verified the measurement reliability by measuring intermolecular weak binding interactions, such as hydrogen bonds and Van der Waals interactions. In addition, we also observed the linearity of the force loading rates, which is applied to the probes by the DEP tweezers, by varying the number of voltage increment steps and thus affecting the linearity of the force loading rates. This system provides a simple and low-cost platform to investigate intermolecular weak binding interactions.

Characterization of the Stiffness of Multiple Particles Trapped by Dielectrophoretic Tweezers in a Microfluidic Device.

Characterization of the stiffness of multiple particles trapped by tweezers-based force spectroscopy is a key step in building simple, high-throughput, and robust systems that can investigate the molecular interactions in a biological process, but the technology to characterize it in a given environment simultaneously is still lacking. We first characterized the stiffness of multiple particles trapped by dielectrophoretic (DEP) tweezers inside a microfluidic device. In this characterization, we developed a method to measure the thermal fluctuations of the trapped multiple particles with DEP tweezers by varying the heights of the particles in the given environment at the same time. Using the data measured in this controlled environment, we extracted the stiffness of the trapped particles and calculated their force. This study not only provides a simple and high-throughput method to measure the trap stiffness of multiple particles inside a microfluidic device using DEP tweezers but also inspires the application of the trapped multiple particles to investigate the dynamics in molecular interactions.

Characterization of anomalous movements of spherical living cells on a silicon dioxide glassy substrate.

The random walk of spherical living cells on a silicon dioxide glassy substrate was studied experimentally and numerically. This random walk trajectory exhibited erratic dancing, which seemingly obeyed anomalous diffusion (i.e., Lévy-like walk) rather than normal diffusion. Moreover, the angular distribution (-π to π) of the cells' trajectory followed a "U-shaped pattern" in comparison to the uniform distribution seen in the movements of negatively charged polystyrene microspheres. These effects could be attributable to the homeostasis-driven structural resilient character of cells and physical interactions derived from temporarily retained nonspecific binding due to weak forces between the cells and substrates. Our results provide new insights into the stochastic behavior of mesoscopic biological particles with respect to structural properties and physical interactions.

Automatic lumen contour detection in intravascular OCT images using Otsu binarization and intensity curve.

This paper proposes an automatic method for the detection of lumen contours in intravascular OCT images with guide wire shadow artifacts. This algorithm is divided into five main procedures: pre-processing, an Otsu binarization approach, an intensity curve approach, a lumen contour position correction, and image reconstruction and contour extraction. The 30 IVOCT images from six anonymous patients were used to verify this method and we obtained 99.2% sensitivity and 99.7% specificity with this algorithm.

Classification of ventricular arrhythmia using a support vector machine based on morphological features.

This paper proposes a method for the classification of ventricular arrhythmia using support vector machines (SVM). The features used in the SVMs were extracted automatically based on morphological information. Three different features were extracted: RR interval, QRS slope, and QRS shape similarity. Then, the SVM was used to classify five different electrocardiogram (ECG) heartbeat episodes. The Gaussian Radial Basis Function was utilized for the kernel function because the ECG beat episodes were treated as a non-linear pattern. The sensitivity of the classification used for the five beat episodes was 93.16%.

Quantitative analysis of H5N1 DNA hybridization on nanowell array electrode.

A nanowell array electrode-based electrochemical quantitative system without amplification was developed and applied for the detection of H5N1 target DNA. An 18-mer probe was immobilized on a nanowell array electrode with a diameter of 500 nm, which was coated with streptavidin and a self-assembly monolayer (SAM). The surface properties of probe DNA hybridization with complementary target DNA were characterized using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The AFM image shows that the depth of nanowell was reduced from 200 nm to 15 nm due to the formation of a DNA hybridization complex on the streptavidin/SAM structure. Differences in charge transfer resistance (deltaR(ct)) in EIS upon hybridization of the probe DNA with complementary target DNA were analyzed and used for the quantitation of H5N1 DNA. This approach shows that the quantitative analysis of H5N1 DNA ranging from 1 pM to 1 microM DNA is possible on a nanowell array electrode.

A new specimen management system using RFID technology.

The specimen management system with barcode needs to be improved in order to solve inherent problems in work performance. This study describes the application of Radio Frequency Identification (RFID) which is the solution for the problems associated with specimen labeling and management. A new specimen management system and architecture with RFID technology for clinical laboratory was designed. The suggested system was tested in various conditions such as durability to temperature and aspect of effective utilization of new work flow under a virtual hospital clinical laboratory environment. This system demonstrates its potential application in clinical laboratories for improving work flow and specimen management. The suggested specimen management system with RFID technology has advantages in comparison to the traditional specimen management system with barcode in the aspect of mass specimen processing, robust durability of temperature, humidity changes, and effective specimen tracking.

Personalized healthcare comment service for hypertension patients using mobile device.

Hypotension and hypertension are chronic diseases, which can be effectively prevented and controlled by constantly monitoring. In this study, personalized healthcare comment service for hypertension patients is proposed and implemented. We have developed algorithms of health state code generation and doctor's comments for patients on case-by-case basis. This prototype service shows how such personalized comments can manage patients with hypertension using blood pressure monitor and mobile device.

Evaluation of performance of several established pitch detection algorithms in pathological voices.

Robust pitch estimation is important in many areas of speech processing. In voice pathology, diverse statistics extracted form pitch estimation were commonly used to test voice quality. In this study, we compared several established pitch detection algorithms (PDAs) for verification of adequacy of the PDAs. In the database of total pathological voices of 99 and normal voices of 30, an analysis of errors related with pitch detection was evaluated between pathological and normal voices, or among the types of pathological voices. Pitch errors of all PDAs used in this study more or less showed some changes between pathological and normal voices. According to the results of pitch errors, gross pitch error showed some increases in cases of pathological voices; especially excessive increase in PDA based on nonlinear time-series. In an analysis of types of pathological voices classified by aperiodicity and the degree of chaos, the more voice has aperiodic and chaotic, the more growth of pitch errors increased. Consequently, it is required to survey the severity of tested voice in order to obtain accurate pitch estimates.

Personal digital exercise trainer for managing, monitoring and recording the exercise.

We developed a portable digital exercise trainer device which manages, monitors and records the user's physical status and workout during exercise session. It guides the user in doing efficient exercise to reach specific fitness goals. It keeps the full exercise program i.e. exercises start date and time, duration, mode, control parameter, intensity in its memory which helps the user in managing his exercise. Exercise program can be downloaded from the internet. During exercise it continuously monitors the user's physiological parameters: heart rate, number of steps walked, and energy consumed. If these parameters do not range within prescribed target zone, the device will alarm the user as a feedback to control exercise. The device displays these parameters on graphic LCD. During exercise it continuously records the heart rate and number of steps walked every 10 seconds along with exercise date and time. This stored information can be used as treatment for the user by an exercise expert. Real-time ECG monitoring can be viewed wirelessly on a remote PC.

An Integrated System for Body Shape Analysis and Physical Fitness Test -HIMS.

Exercise has been proven to be very helpful for maintaining and promoting human health. However, recent research showed that too much or inappropriate exercise may hurt human health. In order to maintain and promote human health, appropriate amount of exercise should be performed according to physical condition and appropriate exercise prescription. This paper proposes an integrated system for body shape analysis (BSA) and physical fitness test (PFT) -HIMS, which consists of 5 data acquisition modules for analyzing physiological status, an exercise load control module, a data processing module and a main control module. The data acquisition modules are integrated to carry out the tests required for exercise prescription in a systematic way. The parameters obtained from the tests include cardio-respiratory endurance, muscle strength, muscle endurance, agility, power, blood pressure at rest, blood pressure at recovery, body fat and body weight. So we can measure 7 kinds of parameters fast and conveniently on one system.

Intensive monitoring system design for cardiological rehabilitation.

In the present study, we investigate mechanisms which to effectively control patients for cardiac rehabilitation. Cardiac rehabilitation exercise includes many things of our present needs and should observe the conditions of the patients accurately at a different level to be sent to physical therapist (PT). The estimated value should be re-sent to patients as a prescription for cardiac rehabilitation exercise. Also, we ask for mechanism that can handle the emergencies rapidly. The thesis will research upon monitoring system on patients for cardiac rehabilitation, health machine control protocols, heart rate control and alarming system. It can be applied to the systems of cardiac rehabilitation.

Asymmetric activation in the prefrontal cortex by sound-induced affect.

This study is based on previous information regarding asymmetric activation in the prefrontal cortex by film-induced affects, as well as the inverse proportionality of prefrontal cortex activity to power in the alpha band of EEG. To search for a specific EEG band where the asymmetric activation in the prefrontal cortex by sound-induced affects is mainly reflected, we measured 32 college students' EEGs; 11 bands ranged from 6.5 to 35.0 Hz, at Fp1 and Fp2 sites. The power in the alpha band (8.0 to 13.0 Hz) at Fp2, especially in the alpha-2 band (9.0 to 11.0 Hz) increased while the students listened to music, during which participants reported positive affect. In contrast, the power at Fp1 increased while the students listened to noise, during which participants reported negative affect. These results imply that sound-induced positive affect increases relative left-sided activation in the prefrontal cortex, whereas induced negative affect elicits the opposite pattern of asymmetric activation.