Biomedical Engineering: Applications, Basis and Communications

Force production involves the coordination of multiple muscles, and the produced force levels can be attributed to the electrophysiology activities of those related muscles. This study is designed to explore the activity modes of extensor carpi radialis longus (ECRL) using surface electromyography (sEMG) at the presence of different handgrip force levels. We attempt to compare the performance of both the linear and nonlinear models for estimating handgrip forces. To achieve this goal, a pseudo-random sequence of handgrip tasks with well controlled force ranges is defined for calibration. Eight subjects (all university students, five males, and three females) have been recruited to conduct both calibration and voluntary trials. In each trial, sEMG signals have been acquired and preprocessed with Root–Mean–Square (RMS) method. The preprocessed signals are then normalized with amplitude value of Maximum Voluntary Contraction (MVC)-related sEMG. With the sEMG data from calibration trials, three models, Linear, Power, and Logarithmic, are developed to correlate the handgrip force output with the sEMG activities of ECRL. These three models are subsequently employed to estimate the handgrip force production of voluntary trials. For different models, the Root–Mean–Square–Errors (RMSEs) of the estimated force output for all the voluntary trials are statistically compared in different force ranges. The results show that the three models have different performance in different force ranges. Linear model is suitable for moderate force level (30%–50% MVC), whereas a nonlinear model is more accurate in the weak force level (Power model, 10%–30% MVC) or the strong force level (Logarithmic model, 50%–80% MVC).

Myosin V, a two-headed motor protein, moves along actin filaments toward the positive end. Similar to other molecular motors, myosin V hydrolyzes Adenosine tri-phosphate (ATP) and releases its product to produce movement. This study proposes a multiple-paths model that considers the hydrolysis processes of catalytic sites at the two heads of myosin V as independent. The proposed model describes the myosin V transition process by seven states, with one load-dependent transition rate among these states. This model demonstrates how myosin V steps forward at different chemical reaction paths. This study also uses the enzyme kinetics to calculate the mean velocity. Stochastic processes are used to analyze the randomness as well. Analytical results reveal that the theoretical mean velocities, mean movement lengths, and randomness with various ATP concentrations under external load agree with the experimental data.

This study added a hand gesture quick interactive operation to the human–machine interface of a leg sport system. Hands are of varying skin color, thus, the background noise and light rays during detection can lead to misjudgments. This study adopted the YC_bC_r color system to detect skin color and minimize the impact of light rays to mark the characteristic point after the skin color had been separated. The system defines three simplified gestures: clenching the fist with the forefinger and reaching out represents the mouse pointer, clenching the fist with the forefinger and thumb and reaching out represents the left button of the mouse, and clenching the fist with the forefinger and little finger and reaching out represents the right button of the mouse, namely clicking the mouse is replaced by hand gestures. The change in the characteristic point is used for operating the hand mouse and interactive connection with games to achieve a preferred presence and feeling of reality.

The release and regulation of growth factors are very important in the tissue regeneration. Optimal and suitable drug carrier systems combined with scaffold are needed to be exploited. In this study, we developed an injectable scaffold incorporated with drug release system for tissue regeneration. Hydrophilic or hydrophobic drugs can be encapsulated into liposomes and then dispersed in the temperature-reversible chitosan-glycerophosphate (GP) hydrogel. Experimental results show that liposomes provide excellent sustained drug release from chitosan matrix when compared with that of free drugs, especially for hydrophilic drugs. The negative charge of the liposome will complex with the positive charge of the chitosan's protonized amine group that results in controlling the drugs release.

Periodontal disease is the manifestation of serious bacteria infection that may extend to the gingival, periodontal ligaments, and alveolus bone. One commonly administrated treatment is the debridement therapy with the removal of infected area including the soft and hard lesion tissues. In some critical case, osteogenetic materials are being filled into the defective voids to improve the regeneration of slow-growing bony tissues. In attempt to improve bone regeneration, chitosan microsphere composites embedded with two osteogenesis beneficial ingredients, CaSO₄ and platelet-rich plasma (PRP), were fabricated by using a high voltage electrostatic field system. Three groups, chitosan/CaSO₄ microspheres (Group A), chitosan/CaSO₄ microspheres mixed with thrombin (Group B), and chitosan/CaSO₄/PRP microspheres mixed with thrombin (Group C) were prepared. And, these chitosan-based composites were evaluated together with a control group in pig oral model for the bone regeneration study. The chitosan/CaSO₄/PRP microsphere composites, exhibiting good sphericity, were in the range of 457.5 ± 59.3 μm in diameter. Defects filled with Group B and Group C showed increases in new bone formation along with fibrous tissue regeneration as compared to that filled with Group A. The Masson's Trichrome stain observations suggested more abundant presence of fibrous collagen matrices around the defects after implanted with Group B over that of Group C microsphere composites. The preparation of chitosan/CaSO₄-based microspheres was straight forward by using high voltage electrostatic field system. Furthermore, Chitosan/CaSO₄-based microspheres with thrombin could be used successfully in regenerating new bone around the alveolus bone area.

In this study, we use laser to fabricate the plastic chamber for animal experiments in vivo. Laser cutting plastics process offers to cut a complex shape at high speed with the absence of hot stress and deformation. We combine this novel method to fabricate the dorsal skinfold plastic chamber and the ear plastic chamber. The chamber was applied on the nude mice and combined with optical system to improve the time of observation and the position of accuracy. The plastic dorsal skinfold chamber (DSC) exhibited good properties than the metallic DSC. The metallic DSC only offered monitoring for more than seven days after implantation. In contrast with the metallic DSC, the plastic DSC enabled monitoring to be observed for more than 12 days after implantation. This plastic DSC and ear chamber are more applications on short-term and long-term mode of disease. These chamber techniques combined with nonlinear microscopy will have many applications in clinic. The nonlinear optical effects have advantages for monitoring the biological processes, such as cellular autofluorescences were excited by two photons excitation and collagen structures were observed by second harmonic generation. The chamber model combines with nonlinear optical microscopy to visualizing cells and tissue structures in vivo. This chamber model allows repeat observation of the same sites for long periods of time and investigation of cells and collagen structures interaction without histological staining and sacrificed animals.

A critical challenge in telerobotic system is data communication over networks without performance guarantee. This paper proposes a novel way of using auditory feedback as the sensory feedback to ensure that the teleoperated robotic system still functions in a real-time fashion under the unfavorable communication conditions, such as image losses, visual failures, and low-bandwidth communication links. The newly proposed method is tested through psychoacoustic experiments with 10 subjects conducting real-time robotic navigation tasks. The performance is analyzed according to an objective point of view (time to finish task, distance away to the target measurements), as well as subjective workload assessments for different sensory feedbacks. Moreover, the bandwidth consumed when auditory information is applied is considerably lower, compared with the visual information. Preliminary results demonstrate the feasibility of auditory display as a complement or substitute to visual display for remote robotic navigation.

The purpose of this study is to build an automatic disease classification algorithm by pulse waveform analysis, based on a Fuzzy C-means clustering algorithm. A self designed three-axis mechanism was used to detect the optimal position to accurately measure the pressure pulse waveform (PPW). Considering the artery as a cylinder, the sensor should detect the PPW with the lowest possible distortion, and hence an analysis of the vascular geometry and an arterial model were used to design a standard positioning procedure based on the arterial diameter changed waveform for the X-axes (perpendicular to the forearm) and Z-axes (perpendicular to the radial artery). A fuzzy C-means algorithm was used to estimate the myocardial ischemia symptoms in 35 elderly subjects with the PPW of the radial artery. Two type parameters were used to make the features, one was a harmonic value of Fourier transfer, and the other was a form factor value. A receiver operating characteristics curve was used to determine the optimal decision function. The harmonic feature vector contain second, third and fourth harmonics (H₂, H₃, H₄) performed at the level of 69% for sensitivity and 100% for specificity while the form factor feature vector derived from left hand (LFF) and right hand (RFF) performed at the level of 100% for sensitivity and 53% for specificity. The FCM- and ROC-based clustering approach may become an efficient alternative for distinguishing patients in the risk of myocardial ischemia, besides the traditional exercise ECG examination.