The absorption spectrum and fluorescence spectrum of thylakoid(sample I) and chlorophyll (sample II) extracted
from brassica chinensis were studied based on polarization technique. As a result, the absorption peak positions of
sample I red shift by more than ten nanometers comparing sample II and the absorption intensities of sample I
declined when the polarizer went round from 0° to 90°. It gave detailed explanation why the two absorption spectra
feel so different. On the other side, the polarization fluorescence spectra of the two samples excited by 437nm were
investigated respectively and the calculation of the fluorescence polarization degree which is determined by the
environment of the pigment, the bound state, the effectual energy transfer and the ordered arrangement of the
pigment in the two samples showed that the pigment in sample I arrayed regularily. The results of the study would
provide powerful reference to the research of the energy transfer and transformation during photosynthesis.
Based on the thermo-elastic mechanism of a pulsed laser in adipose tissue with inclusions, the physical model of generation and transmission of the ultrasound was established. The transient responses of the single pulsed laser interacting with adipose tissue were presented by means of numerical simulation, meanwhile the corresponding stress field and the transmission of the resultant ultrasound were also investigated. By analyzing the laser-induced ultrasonic waveforms in different positions, we found that when the laser acts on the adipose tissue with inclusions, the
inhomogeneity of the tissue leads to different ultrasound modes. This can be attributed to the difference of the optical absorption coefficient between adipose tissues and inclusions. The larger optical absorption coefficient of inclusion in the adipose tissue, the narrower of the full width at half maximum of laser ultrasound signal waveform. Full width at half
maximum of laser ultrasound signal waveform of a pure adipose tissue is wider than that of the adipose tissue with inclusions. The resultant ultrasound signal waveform has larger amplitude in the inclusions with larger optical absorption coefficient than in the pure adipose tissue. The laser ultrasound signal waveform of the adipose tissue with inclusions has
a multiple-interface reflected wave. These results can provide valuable information about further research on methods
and techniques of ultrasonic noninvasive detection of biological organization.
Experimental investigation on cerebral damage of adult SD rats induced by 532nm CW laser was performed. Tissue heat conductive equation was set up based on two-layered structure model. Finite difference algorithm was utilized to numerically simulate the temperature distribution in the brain tissue. Allowing for tissue response to temperature variation, free boundary model was used to discuss tissue thermal coagulation formation in brain. Experimental observations show that thermal coagulation and necrosis can be caused due to laser light absorption. The result of the calculation shows that the process of the thermal coagulation of the given mode comprises two stages: fast and slow. At the first stage, necrosis domain grows fast. Then necrosis domain growth becomes slower because of the competition between the heat diffusion into the surrounding undamaged tissue and the heat dissipation caused by blood perfusion. At the center of coagulation area no neuron was observed and at the transitional zone few nervous cells were seen by microscope. The research can provide reference data for developing clinical therapy of some kind of encephalic diseases by using 532nm laser, and for making cerebral infarction models in animal experiment.
With the increase of people’s living standard and the changes of living form, the number of people who suffer from hypercholesterolemia is increasing. It is not only harmful to heart and blood vessel, but also leading to obstruction of cognition. The conventional blood detection technology has weakness such as complex operation, long detecting period, and bad visibility. In order to develop a new detection method that can checkout hypercholesterolemia conveniently, spectroscopy of cholesterol in hypercholesterolemia serum is obtained by the multifunctional grating spectrograph. The experiment results indicate that, under the excitation of light-emitting diode (LED) with the wavelength at 407 nm, the serum from normal human and the hypercholesterolemia serum emit different fluorescence spectra. The former can emit one fluorescence region with the peak locating at 516 nm while the latter can emit two more regions with peaks locating at 560 nm and 588 nm. Moreover, the fluorescence intensity of serum is non-linear increasing with the concentration of cholesterol increases when the concentration of cholesterol is lower than 13.8 mmol/L, and then, with the concentration of cholesterol increase, the fluorescence intensity decreases. However, the fluorescence intensity is still much higher than that of serum from normal human. Conclusions can be educed from the experiments: the intensity and the shape of fluorescence spectra of hypercholesterolemia serum are different of those of normal serum, from which the cholesterol abnormal in blood can be judged. The consequences in this paper may offer an experimental reference for the diagnosis of the hypercholesterolemia.
Clinical application shows that the Q-switched laser therapy on pigmented lesions based on the principle of selective thermolysis is good in efficiency. But the mechanism of this method of treatment remains unclear yet. Elementary researches are up to date restricted to the levels of morphological observation mainly. The beginning split second process within which laser pulse is interaction with dermal tissues has not been investigated in detail. This process also includes a series of sub processes of super high intensity of photo thermotics, plasma shock wave, super express boil inflation, et. Researches of experimental tests to the momentary processes mentioned above have been performed in this project. The results suggest that laser ablation impact and shock wave induced by laser play important rules in the process.
The technique of fluorescence spectroscopy is applied to study thioredoxin reductast (TrxR) in the cells of human brain. Experimental results show that, by the ultraviolet light irradiation (λmax=253.7nm), TrxR is able to emit two striking spectral bands of 287nm to 484nm and 560nm to 720nm. The spectral profile also consists of some narrow spike-like bands atop these two broad bands. With the concentration of TrxR decreases, the narrow spike-like bands disappear little by little. Furthermore, physical and biochemical mechanisms of fluorescence production for ultraviolet light-induced TrxR spectra and its characteristics are analyzed. The new spectroscopic information suggested in this paper may represent an effort of better understanding of the structure and conformation changes of TrxR.
In order to investigating the effect of wavelength on laser blood therapy, we test the fluorescent spectra of human blood. The wavelengths of exciting lights are 530 nm and 632.8 nm respectively. The result indicates that the light of 530 nm induces much stronger fluorescence, and the emitting spectra induced by 632.8 nm is rather different from the spectra induced by the light of 530 nm. This result suggests that the processes of interaction between laser and blood vary with the wavelength of the radiating lights, so the biological effects of the light to blood can differ with wavelength. These facts might have some meanings to the further research for explaining mechanisms of the laser blood therapy.
The purpose of this research was to investigate the influence of low-level laser radiation on erythrocyte membranes. The method of seif-hemolysis test of erythrocyte was employed in the research. Blood is taken from the vein of a healthy human. The blood was diluted by physiological salt water. Samples ofthe blood are divided into laser groups and control groups. Each sample of the blood was of 2m1 in volume and was put in a test tube. Each test tube of laser groups was radiated by He-Ne laser for about 40 minutes. The output power of laser vary from 1 mW to 8mW for different test tubes. After the laser radiation, the sample of the blood in test tubes was kept in 37CC for 24 hours, and then was tested for the haemolytic ratio. The result of the research showed that the haemolytic ratio of erythrocyte of laser groups was slightly larger than that of the control groups, and the bigger of the laser power, the larger of the haemolytic ratio of erythrocyte. This result indicates that the low-level laser radiation on blood can influence the membranes of red blood cell. This influence can be a stimulation to red blood cells. It can improve the membranous property and functions of red blood cell under some conditions. This result would be helpful to understand the mechanisms of the Intravascular Low-Level Laser Irradiation Therapy (ILLLIT).
Native fluorescence spectral characteristics of red blood cells were studied in the visible region in this paper. Blood samples were collected from normal small albino rats. Native fluorescence spectra of the erythrocyte were induced using Light Emitting Diode (LED) at yellow wavelength about 570+/- 16 nm ((Delta) (lambda) 0.5approximately equals 32nm). As the rat's erythrocyte content of in physiological water is increasing, the fluorescent primary emission peak is red shifted from 588 nm to above 615 nm. Furthermore, the fluorescence intensity at about 600 nm was found to be maximal while the rat's erythrocyte consistence is 1%. Moreover, it is shown in large numbers of experiments that LED-induced fluorescence spectra of the erythrocyte are similar with the whole blood. It may make sense for low- intensity light therapy.
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