In order to understand biological phenomena accurately, single molecule techniques using a physical research approach to molecular interactions have been developed, and are now widely being used to study complex biological processes. In this review, we discuss some of the single molecule methods which are composed of two major parts: single molecule spectroscopy and manipulation. In particular, we explain how these techniques work and introduce the current research which uses them. Finally, we present the oral biology research using the single molecule methods.
Biological Phenomena ; Biological Processes ; Biology ; Methods ; Molecular Biology ; Optical Tweezers ; Spectrum Analysis

The fungal bioluminescence pathway (FBP) is a metabolic pathway responsible for the generation of bioluminescence derived from fungi. This pathway utilizes caffeic acid as the substrate, generating a high-energy intermediate, and the decomposition of which yields green fluorescence with a wavelength of approximately 520 nm. The FBP is evolutionally conserved in luminescent fungal groups. Unlike other bioluminescent systems, the FBP is particularly suitable for engineering applications in eukaryotic organisms, especially in plants. Currently, metabolically engineered luminescent plants are able to emit visible light to illuminate its surroundings, which can be visualized clearly in the dark. The fungal bioluminescent system could be explored in various applications in molecular biology, biosensors and glowing ornamental plants, and even green lighting along city streets.
Luminescence ; Light ; Fluorescence ; Eukaryota ; Green Light

The health-promoting qualities of ultraviolet light have been well recognized, but it also induces deleterious effects from sunburn to skin cancer, Since our enviroment exposes us to both ultraviolet and infrared rays at the same time, the latter is considered to influence to some extent the cutaneous effects of the former. In recent years, it has become increasingly apparent that the biologic effects of one type of radiation may be modified by wavelengths of different energies. Interactions of this kind are complex and occasionally result in true synergy or antagonism. Although there are several reports on these interactions, the results are not in accordance. This study was undertaken to investigate the influence of infrared radiation (IR) on ultraviolet radiation (UVR)-induced skin injury, especially minimal erythema dose (MED). Thirty-five healthy medical students participated in this study between May and June, 1983. One side of the back was exposed to IR with UVR while as a control the other side was exposed only to VVR. The results were summarized as follows : 1. In one experiment treated with IR before UVR, the mean MED-S.D. of the treated site was 17 7+5 3 (sec) and that of the control site was 18. 3-+6. 4 (sec)- The increase of the MED was statistically significant. (p<0. 01], paired t-test) Among the fifteen subjects, the MED was increased in 73% (11/15), and the same in 27% (4/15).
Erythema ; Humans ; Infrared Rays ; Skin Neoplasms ; Skin* ; Students, Medical ; Sunburn ; Ultraviolet Rays

The mutagenic effect of HpD on cell SCE and the reactions of cell SCE to different sources of light combined with HpD were studied using V79 cells. There were 6 doses of HpD: 1 microgram/ml, 3 micrograms/ml, 5 micrograms/ml, 10 micrograms/ml, 50 micrograms/ml and 100 micrograms/ml. The dose of 5 micrograms/ml is equal to the maximum dose of HpD used in the clinic (HpD per milliliter of patient's blood). Our experiments demonstrated that when the cells were cultured in the dark and HpD was added to the medium no more than 5 micrograms/ml, the SCE frequencies were not increased. The cells were irradiated with different sources of light without HpD, both the fluorescence and ultraviolet light could promote SCE but the light of daylight lamp and red light did not increase it. But when HpD was added into culture medium at the dose of less than 5 micrograms/ml, every light could increase the cell SCE intensively except the daylight lamp light. The red light was more notable than the others by relation analysis.
Cells, Cultured ; Fluorescence ; Hematoporphyrin Photoradiation ; Hematoporphyrins ; pharmacology ; Humans ; Light ; Photochemotherapy ; Sister Chromatid Exchange ; drug effects ; Ultraviolet Rays

At present, current stimulation, ultra-sound, and light therapy have become effective methods to promote wound healing. Among them, infrared light is the most widely used method and is one of the important methods to promote wound healing. The therapeutic effect of infrared light on wounds is related to the effect of photobiomodulation on cells and molecules on the skin surface, but the mechanism by which photobiomodulation of infrared light promotes wound healing has not been fully elucidated. Therefore, it is necessary to study the action characteristics and the mechanism of photo-biomodulation of infrared light in promoting wound healing. This article reviews the effect of different types of infrared light on wound healing and the mechanism of infrared light in promoting wound healing.
Infrared Rays ; Low-Level Light Therapy/methods* ; Wound Healing/physiology*

PURPOSE: Heat therapy by heat lamp after microvascular surgery is being used for preventing blood vessels's contraction and blood-flow's disturbance. As usually, incandescent lamp has been used. But there have been several problems and need for improvement in the existing heat lamp treatment. So we would like to introduce improved heat lamp to keep an appropriate temperature and intensity of illumination. METHODS: The existing heat lamps are the ones of general light stands covered with newspaper, having 60 watt light bulb of incandescence and lampshade made of aluminum. We have tried to improve shortcomings of the existing heat lamps by enlarging the size of aluminum lampshade and attaching a curtain that can block heat and light. We conducted a comparative study between the existing and improved heat lamps. Under the assumption that there are several affected parts, we have also measured the distance from heat lamp to patients' eye region and then intensity of illumination. RESULT: The target temperature of surface was realized in 11 minutes with the maximum temperature reaching at 36.6 degrees C in 28 minutes at the existing heat lamp while the target temperature reached in 7 minutes with the maximum temperature reaching at 39.0 degrees C in 17 minutes at the improved heat lamp. The existing and improved heat lamp showed 38 lx and 0.1 lx of intensity of lumination, respectively. CONCLUSION: Using improved heat lamps, we can keep an appropriate temperature and we think we can make contribution to patients' treatment by making them and their neighbors able to sleep with minimized disturbance thanks to low intensity of illumination secured by blocking light.
Aluminum ; Contracts ; Eye ; Hot Temperature ; Incandescence ; Light ; Lighting ; Periodicals ; Spasm

Due to the high variation in test results of indirect enzyme-linked immuno sorbent assay (ELISA) and complicated steps involved in the process of standardization, a platform used for standardizing the test results from indirect ELISA was developed. The platform was designed based on 'Improved Standardization Method for Optical Density' (I-STOD). Gauss-Newton iteration was applied to estimate parameters in a standard formula. Programming Language VB was used for developing interface of platform. The results indicated that the validity of experiment could be verified through platform. A well determined scope of standardization could be generated. The sample with concentration within the scope was standardized and the degree of dilution was calculated for those outside the scope. The platform was successfully developed which normalized the process of standardization. The function provides the researchers with an effective and convenient tool for quickly achieving standardization of ELISA test results.
Antibodies ; analysis ; Enzyme-Linked Immunosorbent Assay ; methods ; standards ; Humans ; Optical Phenomena

OBJECTIVE: To assess the driving ability of older drivers, their visual function, cognitive-perceptual function, motor function and driving performance were evaluated. METHOD: Subjects were 55 drivers aged 65 years or older. Visual function test included visual acuity, visual field, color vision and contrast sensitivity. Cognitive perceptual function was evaluated with the cognitive perceptual assessment for driving (CPAD) and clock drawing test. For motor function, muscle strength and range of motion were evaluated. Driving performance was evaluated by virtual reality based driving simulator. For comparision, 48 younger drivers aged between late twenties and early forties underwent the same evaluation. RESULTS: Among older drivers, 21 (38.2%) had visual acuity less than 20/40, 3 (5.5%) had visual field narrower than 140degrees bilaterally. Contrast sensitivity was significantly decreased in both day and night with glare light conditions. In cognitive-perceptual function assessment, 20 subjects (36.4%) passed CPAD test, 3 subjects (5.5%) failed, and 32 subjects (58.1%) fell into borderline group. Mean CPAD score was 50.65+/-5.62, which was significantly lower than that of younger drivers. 18 subjects (32.7%) were incorrect in clock drawing test. In motor function assessment, 4 subjects (7.3%) in older drivers showed hemiparesis secondary to stroke. In driving simulator, 21 subjects (38.2%) failed whereas only 4 subjects (8.3%) did in younger drivers. Average demerit score was 24.09+/-15.53 and was significantly higher than that of younger drivers. CONCLUSION: Older drivers showed significantly higher incidence of visual and cognitive-perceptual dysfunction, and poorer driving performance compared to younger drivers group.
Aged ; Automobile Driving ; Cognition ; Color Vision ; Contrast Sensitivity ; Geriatric Assessment ; Glare ; Humans ; Incidence ; Light ; Muscle Strength ; Paresis ; Range of Motion, Articular ; Stroke ; Visual Acuity ; Visual Fields

PURPOSE: Optical molecular luminescence imaging is widely used for detection and imaging of bio-photons emitted by luminescent luciferase activation. The measured photons in this method provide the degree of molecular alteration or cell numbers with the advantage of high signal-to-noise ratio. To extract useful information from the measured results, the analysis based on a proper quantification method is necessary. In this research, we propose a quantification method presenting linear response of measured light signal to measurement time. MATERIALS AND METHODS: We detected the luminescence signal by using lab-made optical imaging equipment of animal light imaging system (ALIS) and different two kinds of light sources. One is three bacterial light-emitting sources containing different number of bacteria. The other is three different non-bacterial light sources emitting very weak light. By using the concept of the candela and the flux, we could derive simplified linear quantification formula. After experimentally measuring light intensity, the data was processed with the proposed quantification function. RESULTS: We could obtain linear response of photon counts to measurement time by applying the pre-determined quantification function. The ratio of the re-calculated photon counts and measurement time present a constant value although different light source was applied. CONCLUSION: The quantification function for linear response could be applicable to the standard quantification process. The proposed method could be used for the exact quantitative analysis in various light imaging equipments with presenting linear response behavior of constant light emitting sources to measurement time.
Animals ; Bacteria ; Cell Count ; Enzyme Multiplied Immunoassay Technique ; Imidazoles ; Light ; Luciferases ; Luminescence ; Nitro Compounds ; Optical Imaging ; Photons ; Signal-To-Noise Ratio

OBJECTIVETo modify biomacromolecules, such as chitosan and collagen, to synthesize a mineralized template that will induce self-growing remineralization of tooth enamel.

METHODSNatural polycation polysaccharide chitosan was modified through phosphorylation to synthesize the polyanion derivative ofphosphorylated chitosan. Parent hydrogels com- bined with chitosan and collagen I were built through peptide binding reaction using genipin as a crosslinker. The gels self- assembled on the tooth's inert surface, which was stimulated by ultraviolet radiation. The bionic saliva provided mineralized ion, and then the hydroxyapatite assembled and grew in situ on the tooth.

RESULTSThe functional group P04(3-) (3,446 cm(-1)) was grafted on chitosan as confirmed by the Fourier transform infrared spectroscopy. The porous polyelectrolyte complex hydrogel formed by the interaction between the polycation chitosan and the polyanion phosphorylated chitosan could induce hydroxyapatite crystal nucleation and growth on the hydrogel fiber surfaces. The neonatal crystal was hydroxyapatite as confirmed by X-ray diffraction and was tightly connected to the tooth. A continuous structure of column crystals with sizes ranging from 30 nm to 60 nm was observed. The structure was in parallel direction similar to the direction of the enamel rod, and its hardness was close to dentin.

CONCLUSIONThe parent hydrogels that were easily obtained and controlled could mimic the template of the enamel mineralization and induce a self-growing hydroxyapatite, which is an important step in the structural bionics of enamel.

Biocompatible Materials ; Chitosan ; Collagen ; Dental Enamel ; Durapatite ; Microscopy, Electron, Scanning ; Polymers ; Spectroscopy, Fourier Transform Infrared ; Tooth ; Tooth Remineralization ; Ultraviolet Rays ; X-Ray Diffraction