Mechanical force has essential effects on cellular behaviors such as proliferation, migration and differentiation, and the mechanism of mechanotransduction is still one of the hot spots in mechanobiology study. Traditional methods could not provide accurate evaluation of the protein activation signal upon mechanical stress application. The development of fluorescence protein technology greatly promoted the understanding of mechanotransduction. In particular, genetically-encoded biosensors based on fluorescence resonance energy transfer (FRET) technique has achieved a real-time dynamic observation of living cell signal protein activity, which provides a powerful tool for the in-depth study of biomechanics. In this paper, we provide a summary on recent progress of FRET application in biomechanics. Firstly we introduce the FRET technology, and then we summarize three methods to integrate the mechanical stimulation with the FRET imaging system on cell experiments. After that, the important progress of biomechanical research on signal pathway made by FRET technology, such as cytoskeleton, Rho family, calcium and cellular physical stress visualization, are also discussed. Finally, we point out the bottleneck of the future development in FRET technology, and also make the prospect of the application of FRET in mechanotransduction. In summary, FRET technology provides a powerful tool for the studies of mechanotransduction, which will advance our systematic understanding on the molecular mechanisms about how cells respond to mechanical stimulation.
Biomechanical Phenomena ; Biosensing Techniques ; Fluorescence Resonance Energy Transfer ; Humans ; Luminescent Proteins ; chemistry ; Mechanotransduction, Cellular ; Microscopy, Fluorescence ; Signal Transduction ; Stress, Mechanical

No abstract available.
Emergencies ; Humans ; Linear Energy Transfer

A biphasic porous medium model based on the mixture theory in continuum mechanics frame was used to depict the distributions of osseous stress field, distortion field and pore pressure when the bone tissue was subject to various dynamic loads. In the model, the bone tissue was considered as a transversely isotropic, liquid saturated porous material. The coupling relationship among the distortion, fluid flow and the streaming potential is studied. The Galerkin weighted residual method was used to derive the finite element formulation for dynamic response and the streaming potential calculating formulation of bone tissue, the penalty finite element formulation was obtained via introducing the ratio term of pressure p and penalty parameter beta in the continuity equation and, in turn, eliminated the pressure term in governing equation sets. The computational results show that the viscoelastic behavior and the energy dissipation property in the bone tissue, especially in the cancellous bone, is caused to a great extent by the pore liquid flow and diffusion. Meanwhile, because of the existence of electrical double layer between the solid phase and liquid phase, when the liquid constituents in the pore diffuse, the streaming potential appears, and the growth and absorption of bone tissue is expedited.
Biomechanical Phenomena ; Biophysical Phenomena ; Biophysics ; Bone and Bones ; physiology ; Elasticity ; Electrophysiology ; Finite Element Analysis ; Humans ; Models, Biological ; Porosity ; Stress, Mechanical ; Viscosity

Objective To investigate the fluorescence resonance energy transfer (FRET) effect between dylight (DL) and AuNP (AuNP), and to construct a new fluorescence immunoassay for insulin in combination with the immunocompetition method. Methods Insulin antigen (Ag) and insulin antibody (Ab) were conjugated with DL and AuNP respectively to form DL-Ag conjugate and AUNp-AB conjugate. A novel fluorescence immunoassay for insulin was developed on the basis of FRET effect and the immune competition response between them. Then the performance of the method was evaluated and its application in actual samples was explored. Results The fluorescence immunoassay showed high sensitivity (0.015 ng/mL), short measurement time (4 min) and good specificity. It was successfully used in the measurement of serum insulin, and the recovery was between 96.9% and 121.1%. Conclusion FRET effect between AuNP and DL can be applied to develop a fluorescence immunoassay for the measurement of serum insulin.
Fluorescence Resonance Energy Transfer ; Insulin ; Immunoassay

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfill the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest.
Korea ; Linear Energy Transfer ; Neutrons ; Protons

OBJECTIVES: It is difficult to carry and set up a large numbers of computers when computerized neurobehavioral tests are performed to many subjects. There are difficulties in mobilizing and resetting desktop computers and so, the use of desktop computers will decrease due to the recent increasing popularity of laptop computers. However, it is essential that there is no difference between the tests performed on a laptop and on a desktop computer. This study was conducted to estimate the effect that the type of computer has on computerized neurobehavioral performance tests. METHODS: Three types of computers were applied. Type 1 was a normal laptop computer. Type 2 was a laptop computer that was remodeled and equipped with a modified keyboard. A common desktop computer with a remodeled keyboard as type 3. The computerized tests included Simple Reaction Time, Choice Reaction Time, Symbol Digit, and Finger Tapping Speed. A total of 60 subjects were examined by the identical tester in the same testing conditions. The computers were randomly allocated, which were used in the test and let examinees take tests with the separate computers. RESULTS: There were no significant differences among the computers for the results of the Simple Reaction Time and Finger Tapping Speed tests. The mean reaction time, error number of Choice Reaction Time and mean reaction time, correct mean reaction time, error number of Symbol Digit produced significantly different results among the three types of computers. CONCLUSION: This study indicates that with only a laptop computer the Simple Reaction Time test using the space bar was useful. But with the laptop computer, the Choice Reaction Time test using the four-direction key and the Symbol Digit test using the upper end number key were unsuitable. The keyboard should be developed further for the Choice Reaction Time and Symbol Digit tests. Among the three computers, we recommend the use of the desktop computer with the remodeled keyboard which the examinees are familiar with and the laptop computer with the remodeled keyboard.
Fingers ; Linear Energy Transfer ; Reaction Time

Dental Models ; Linear Energy Transfer ; Orthognathic Surgery

The aim of this study was to detect the relationship between age and biomechanical properties in porcine common bile duct (CBD). The CBDs of 50 Hubei white pigs aged 3-12 months were obtained. The experiment of pressure-diameter was conducted on the biomechanical experiment stand for soft tissues, and then the elastic modulus and compliance were calculated. The materials were transversely extracted, refrigerated, and sliced up before HE staining. The diameter and wall thickness of the CBD were measured by a computer image analysis system. The results showed that there was statistically significant difference in regard to the compliance of the porcine CBDs of different months (F = 59.69, P = 0.00). The compliance of the porcine CBD increased gradually with monthly age. However, after the pigs being aged 10 months, the compliance decreased gradually with monthly age. The compliance of the CBD of pigs aged 7-10 months was not significantly different (P > 0.05), but the compliance of the CBDs of pigs' aged 3-6 months and 11-12 months was significantly lower than that of pigs aged 7-10 months (P < 0.01). The changes in elastic modulus of porcine CBD with age were opposed to the changes in compliance. The results of the present study suggests that the in biomechanical properties of pigs' CBDs change with their ages, and the CBDs of pigs aged 7-10 months have good compliance. Thus, for the pig-to-human liver xenotransplantation, the livers of pigs aged 7-10 months, being chosen as donators, may be more conducive to matching.
Age Factors ; Aging ; physiology ; Animals ; Biomechanical Phenomena ; Biophysical Phenomena ; Common Bile Duct ; anatomy & histology ; physiology ; Compliance ; physiology ; Elastic Modulus ; physiology ; Swine ; Transplantation, Heterologous

Meridian essence has been investigated through anatomy, electrophysiology, biophysics, and biochemistry. Various hypotheses of meridian essence exist, but no hypothesis can truly reflect the internal character of Chinese medicine (CM). The research of meridian essence requires a holistic viewpoint and innovative awareness. Initially, any hypothesis regarding meridian essence should begin with observation of the human body. Secondly, the research should arise from the meridians' physical functions and pathological changes, so as to maintain the fundamental nature of the meridians themselves. Thirdly, the research should be based upon the theory of CM, yet coupled with the integration of modern techniques to deepen our understanding of the scientific contents of meridians. Fourthly, theoretical research should be combined closely with clinical practice, in order to test the achievements in actual conditions. Lastly, more attention should be given to negative results in studies to more accurately discover the real essence of meridians.
Biophysical Phenomena ; Electrophysiological Phenomena ; Humans ; Meridians

The theory of fluorescence resonance energy transfer (FRET) and methods of fluorescence detection in fluorescent-quantitative polymerase chain reaction (FQ-PCR) are introduced in this article. Applications of FRET in fluorescence detection of PCR are emphatically discussed, and FRET research progress and future trends are pointed out too.
Fluorescence Resonance Energy Transfer ; methods ; trends ; Polymerase Chain Reaction ; methods