Biomedical Engineering: Applications, Basis and Communications

We have reported the successful use of the Loop Mediated Isothermal Amplification (LAMP) reaction for Hepatitis B Virus (HBV) DNA in a 25 μl micro-reactor for the development of a rapid diagnostic device recently. This method shows the successful amplification of HBV DNA with high specificity and sensitivity efficiently within one hour. Such a powerful method can be used for many other fast diagnostic applications with the help of optimal primer design and miniaturization of reactor. In this report, we will first summarize the general design rules for primer design from literature reviews and our experimental results. We will discuss the effects of HBV primers and concentrations of working buffers for optimal performance.

This study constructs new L-ascorbic acid (LAA) composites in low toxicity and high stability for feasible application. Although literature reveals that sodium thiosulphate could stabilize the activity of LAA, our findings show that the significant toxicity was provoked by sodium thiosulphate. A safe and non-toxic material montmorillonite (MMT) was thus used to attenuate this toxicity and to sustain the stability of composites with economic feasibility for practical use. As the proton released from LAA promots the increases of interlayer spacing of clay layers in MMT, the formation of stable and safe LAA composites resulted. The most feasible were found to be the composites [MMT + 10% LAA + 0.90% Na₂S₂O₃] and [MMT + 5% LAA + 1.35% Na₂S₂O₃].

Conventional blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been wildly used in neuroscience studies. Even though the BOLD method offers the functional information, the low signal-to-noise ratio could not provide an activated brain area accurately and the signal could not be easily inspected from the complicated neuronal interactions. In this regard, the present study aims to use an ultra-small super-paramagnetic iron oxide (USPIO) nanoparticle coated with covalently bound bifunctional poly(ethylene glycol) polymers to enhance the brain functional responses by the IRON (increased relaxation with iron oxide nanoparticles) technique. The R₁ and R₂ of this USPIO were 53.6 mMsec^-1 and 359.8 mMsec^-1, respectively, and both were higher than most of the commercial products under 0.47 T nuclear magnetic resonance measurement. In this study, the time activity curves in responsive brain areas were evaluated following USPIO injection (3 mg of Fe/kg). The amphetamine (2 mg/kg) was used as a functional stimulator to reveal the changes of relative cerebral blood volume in different brain areas. All imaging experiments were performed by Bruker Biospec BMT 47/40 4.7 T MRI system. The results show that, compared to the BOLD signals; significant event related responses were observed in striatum, insular cortex, nucleus accumbens, somatosensory cortices, and lateral thalamus using the IRON technique. Furthermore, the usability of this USPIO in detecting rCBV responses was confirmed by comparing with previous researches.

Among all the joints in the human body, the elbow joint is the one which most easily suffers from stiffness. Thus, a progressive stretching static adjustable elbow splint is necessary for a post-traumatic or post-operative situation in treating of elbow problems. We developed a new type of static adjustable elbow splint, which can provide flexion and extension in a wide range of motion. The splint also has a self-adjustable spiral rod. Patients can adjust the motion arc according to his tolerance, which may reduce the iatrogenic injury caused by forceful manipulation. The splint has two rotation hinges to provide self-adjustment of rotation center. We can apply this new type of splint for post-operative rehabilitation of elbow surgery, such as fracture-dislocation fixation, contracture release, arthroplasty and non-operative treatment of elbow injury.

A new type of electromagnetic vibration transducer designed to be placed onto the tympanic membrane will be developed. Such an electromagnetic transducer should have the following characteristics: small in size, high-energy efficiency and suitable frequency bandwidth. In order to find out the optimal electromagnetic force and to predict the frequency-amplitude characteristics, a finite element middle ear biomechanical model was used to derive the optimal magnetic force of the actuator in this study. First, the electromagnetic transducer coupled to the ear drum was created by using a computer-aided design (CAD). Then the new coupled tympanic membrane-transducer complex was loaded to a 3-dimensional biomechanical model in the middle. The air gap between magnet and coil, input current and vibration force were calculated by finite element analysis simulation. In addition, gain and frequency response curves of the actuator were also calculated. Predicted displacement of tip of the malleus induced by the sound pressure of 80 dB SPL with different input currents are computed from the finite element model over the auditory frequency range of 100–8000 Hz as the force input into the ANSYS software. Simulated results show displacements of vibration are about 100 nm in the range from 100–1000 Hz and reduced when the frequencies are higher than 1000 Hz. Functional gains were about 20–25 dB across the 100 to 8,000 Hz frequency range.

Pulse parameters calculated from the LDF waveform based on a time-domain synchronized averaging analysis were shown to be able to discriminate the difference in microvascular resistance. However, its applicability may depend on the validation of signal stationarity. In this study, our aim is to investigate the effect of pulse number, which may destroy the signal stationarity, on various pulse LDF parameters. Analysis was performed in data obtained on healthy volunteers. When one pulse parameter is deviated from the standard value for more than 10%, it was regarded as an error; EP (error probability) was then defined as the occurring probability of error. It was revealed in this study that average parameter deviations for FDT and PDT were smaller than 5% for all tested pulse numbers. If we set 10% as the parameter-deviation criterion as well as the acceptable EP range, there should be at least 120 pulses for FDT and PDT, and 210 pulses for FNA and PW. The study presented here has established the criteria for appropriate pulse number to achieve the signal stationarity; we can thus get accurate pulse parameters so that the microcirculatory discriminability of the pulse-based time-averaging analysis on LDF signal can be improved. The proposed quantitative method to verify the validation of signal stationarity when utilizing time-averaging can also be applied to analysis of other bio-signals.

This paper presents the design and implementation of a tele-emergent system to provide constant monitoring of cardiac patients. Our system is consisted of a user integration device attached to the patient, a wireless sensor network (WSN) and a medical gateway installed in the patient's home, and a server set up in the hospital. The user integration device includes Electrocardiogram (ECG) signal acquisition and processing circuit utilizing a "Modified So and Chan" QRS detection algorithm to discriminate the R signal wave and calculate RR intervals to subsequently detect abnormal Heart Rate Variability (HRV), and a Bluetooth transmission module to communicate with WSN. The WSN which is consisted of wireless sensor nodes with power-saving scheme is used to relay the ECG data to the medical gateway for ubiquitous monitoring at home. The medical gateway includes the heart disease symptom recognition system to further analyze the ECG data and recognize the symptoms of serious heart diseases, and a General Packet Radio Service (GPRS) module with Multimedia Messaging Service (MMS) to communicate with the server in the hospital. The server in the hospital can passively process the MMS messages from the medical gateway, and actively send commands to the medical gateway to acquire the needed ECG data from the patient. With our integrated system it is possible to provide real-time and long-term monitoring of physiological data for cardiac patients which is vital for the patients' medical care.

With the intention of creating excellence in Dr. Lun Ci Yuan's diagnosis system in traditional Chinese medicine, multiple factors, criteria and types technique based on approximate reasoning is developed in this paper. The technique can sum up an expert's experience into computer. The diagnosis system has been successfully used to diagnose and treat arrhythmia.