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As an optical microscope with high resolution, two-photon excitation (TPE) fluorescence microscope is widely used in noninvasive 3D optical imaging of biological samples. Compared with confocal laser scanning microscope, TPE fluorescence microscope provides a deeper detecting depth. In spite of that, the image quality of sample always declines as the detecting depth increases when a noninvasive 3D optical imaging of thicker samples is performed. Mouse oocytes with a large diameter, which play an important role in clinical and biological fields, have obvious absorption and scattering effects. In the present paper, we performed compensation for two-photon fluorescence images of mouse oocyte chromosomes. Using volume as a parameter, the attenuation degree of these chromosomes was also studied. The result of our data suggested that there exists a severe axial intensity loss in two-photon microscopic images of mouse oocytes due to the absorption and scattering effects. It is necessary to make compensation for these images of mouse oocyte chromosomes obtained from two-photon microscopic system. It will be specially needed in studying the quantitative three-dimensional information of mouse oocytes.

By using five-laser resonance excitation in combination with a new detection method, the highly-excited double Rydberg states NLn'l (N ≥ 40, N/n' ≥ 0.5 and L, l < 4) of Yb have been observed. The relative excitation strengths between the Δl allowed and forbidden core transitions can be quantitatively measured. Analysis of the spectra has revealed the strong electronic correlation in such highly excited states.

By the unique ability of measuring concentration and diffusion coefficient, fluorescence correlation spectroscopy (FCS) has kept enlarging and deepening its application fields which need measuring physicochemical properties in complex mixtures. However, the classical data processing method in FCS generally induces errors in the fitting parameters, and the intuitionistic information in the chart is little or confused. Aiming at the above problems, we tried a new data processing method with differential treatment to find out whether it has multi-fluorescent-components and estimate the parameters intuitionally in the chart. The differential curves of treated autocorrelation curves have various positions, depths and full widths at half depth of the trough, by which the characteristic diffusion time and the number of the fluorescent components are decided. This improved processing method provides help for the FCS measurement in complex environment of life.

In recent years, by the unique ability in measuring concentration and diffusion coefficient, fluorescence correlation spectroscopy (FCS) kept enlarging and deepening its application fields which need measuring of physicochemical properties in complex mixtures. However, the classical data processing method in FCS, generally induces errors in the fitting parameters, and the intuitionistic information in the figure is little. In this paper, we tried new data processing method with differential treatment, to find out whether it has multi-fluorescent-components and estimate the parameters intuitionally. The differential curves of treated autocorrelation curves have various positions, depths and the full widths at the half depth of the trough, by which the character diffusion time and the number of the fluorescent components are decided. This improvement of processing method provides help for the FCS measurement in complex environment of life.

The blue shift of a two-photon excitation absorption peak allows the application of a single wavelength to the simultaneous excitation of several fluorochromes with disparate emission characteristics. An output at 730 nm of a mode-locked femtosecond Ti-sapphire laser was used to excite four different commonly used fluorochromes, namely Hoechst 33342, Fluo-4, PI and Indo-1, and characteristic fluorescence images were obtained using (455 +/- 15) nm, (540 +/- 15)nm, (580 +/- 16) nm and (500 +/- 15) nm filters respectively. An approach to exciting with a single wavelength, staining with two different fluorochromes, and collecting fluorescence in two separate channels was employed to study mouse preimplantation embryos by 3D and 4D real-time imaging. Combined with the merits of two-photon excitation fluorescence imaging, such as better penetration, less photon-damage, and higher signal-to-noise ratio, this approach was supposed to be a novel multi-parameter investigating tool for mouse preimplantation embryos development study.

Fluorescence fluctuation spectroscopy is a method in which fluorescence fluctuations arising from a very small sample volume are analysed to obtain brightness, diffusion coefficient and concentration of particles. Using Monte Carlo simulation, the influences of background autofluorescence and noises on fluorescence fluctuation spectroscopy are studied. Results show that a two-component photon counting histogram can effectively remove the effects due to background autofluorescence from low brightness and high concentration components and uniform noise. The result will help to bring applications of fluorescence fluctuation spectroscopy to intracellular environment.

In this paper, we determined the ratio of C13/C12 of methane in slurry gas from oil wells by the method of laser frequency modulation absorption spectroscopy that has many advantages such as high precision, high spectroscopic resolution and rapidly and simply dealing with samples. This technique provided us with a subsidiary method for oil-gas source exploration. The method of laser frequency modulation absorption spectroscopy is based on the method of laser frequency absorption spectroscopy and is more accurate. And this method can be expanded to apply to others aspects easily. We only need change other appropriate laser and select right absorption peak, then we can determined the ration and concentration of diverse gases.

Two-photon Laser Scanning Microscopy (TPLSM) is a novel technique based on the two-photon excitation of fluorophore. In this paper, TPLSM and traditional confocal microscopy are introduced. And the influence of femtosecond near-infrared (NIR) illumination on mouse embryos is investigated for the first time. The result shows that NIR laser has much less damage to embryos than blue laser and proves that TPLSM is superior to conventional confocal microscopy in keeping sample alive. TPLSM enables us to make a continuous observation for a longer time on embryogenesis.

The type-I ribosome-inactivating protein trichosanthin (TCS) has a broad spectrum of biological and pharmacological activities, including abortifacient, anti-tumor and anti-human-immunodeficiency-virus (anti-HIV). In this study, circular dichroism (CD) and capillary electrophoresis were used for the first time to study TCS and its two TCS mutants of Y55G TCS (tyrosine 55 converted to glycine) and FYY140-142GSA TCS (tripeptide phenylalanine-tyrosine-tyrosine 140-142 converted to glycine-serine-alanine). The results indicated that the substitution of amino acids changed the secondary structures and the hydrophobility of TCS. Moreover, both Y55G TCS and FYY140-142GSA TCS demonstrated attenuated cytotoxicity and reactive oxygen species (ROS) production in human choriocarcinoma cells (JAR cells) as compared to natural TCS and wild-type TCS. Our results demonstrated the cytotoxicity of TCS on JAR cells and TCS-induced production of ROS might be TCS-conformational related, suggesting that CD and capillary electrophoresis study might throw new insight into the anti-tumor and anti-HIV mechanism of TCS.

Trichosanthin(TCS), a ribosome inactivating protein extracted from the root tuber of a traditional Chinese medicine herb Tian Huo Fen(THF), possessed abortifacient, anti-tumor and anti-human immunodeficiency virus(HIV) activities. For centuries in China, THF has been used as an effective folk medicine to terminate early and midtrimester pregnancies and to treat ectopic pregnancies, hydatidiform moles and trophoblastic tumor. We observed the changes in reactive oxygen species and intracellular calcium in mouse embryos induced by TCS with confocal laser scanning microscopy in combination with the fluorescene diacetate (DCFHDA) and Fluo-3-AM. The results indicated that TCS induced increase in intracellular calcium and production of reactive oxygen species in mouse embryos , and TCS inhibited the development of mouse embryos effectively. Mouse embryos of different developmental stages before implantation are used in the experiments. This provides new insight into mechanism for abortifacient activity of TCS.

Optical tomography is a kind of noninvasive technology in CT field using multiple photon diffusion. With the method of Monte Carlo simulation we carried out some numerical computation of the diffusion transmission disciplinarian in two kinds of simple biological texture. A ring distribution of diffuse light intensity is found and is sensitive to the incident light relative position to the absorption sphere at some certain conditions. The resolution and incident depth are also discussed through analysis of the image in numeric simulation.

Molecular Radar (MR) is a new method to detect biological processes in living cells at the level of molecular, it is also the newest means to get intracellular information. In this paper we study the effect of morphine on PC12 cells using MR. The results show that the effect of morphine on PC12 cells is time- and concentration-dependent. Morphine treating for short time induces the increase and fluctuation of intracellular (CA2+), while morphine treating for long time induces chromatin condensation, loss of mitochondria membrane potential apoptosis.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A new model (3D) of OCT based on wave optics and Huygens- Fresnel Principle is derived in this paper. In this model, both axial and transverse information is included so that it can be used to discuss the image properties in both directions. The model is further simplified by narrow-band approximation and plane wave approximation. As applications of the simplified model, we developed Monte Carlo simulation programs to calculate the transverse resolution and to simulate the axial signal of our OCT system. The results well coincides the experiments.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fluorescence Correlation Spectroscopy (FCS) is an attractive technique for probing the molecular kinetics in solutions. However, gradient field due to a focused intense laser field may affect the measured results. Since finding an analytical solution of the diffusion equation in a gradient field is not easy, we developed a Monte Carlo method to simulate Browning motion of Rayleigh particles in a laser gradient field. Effects corresponding to different parameters were tested in the simulation. Simulated results for zero gradient field agree well with the analytical solution, which has been used in all the conventional FCS measurements. Simulated results with gradient fields indicate changes in the fitted diffusion time and the average number of fluorescent spheres in the effective volume. The simulated results agree qualitatively to the experimental results obtained using fluorescent spheres. Empirical relations from the simulation are discussed.

Two-photon excitation fluorescence microscopy has become increasingly popular in 3D fluorescence imaging of tissue samples. Observation depth is an important indicator for the performance of the technique. Using the principle of tissue optics, we analyzed quantitatively the effects of optical properties, such as absorption coefficient, scattering coefficient, and the scattering anisotropy factor of the tissue, to the observation depth. An analytical relation between the fluorescence and the observation depth has been derived and tested against experimental results for rat aorta elastic lamina.

Optical Coherence Tomography (OCT) is a kind of new tomography technology, which has much important application in biological, medical and material science. In this paper, we make continuations of this technology to found en face imaging of arbitrary object. This enables us to get digital information about the geometrical configuration of a sample with resolution of micrometers in a non-touching mode.

The early detection and treatment of pathological change tissue has long been a medical priority. Optical coherence tomography (OCT) is a new kind of noninvasive cross- sectional imaging technique. In this paper, experimentally we set up the first OCT system in China that can be obtaining 2D image of biological samples. OCT performs optical ranging in tissue by use of a fiber-optic Michelson interferometer with a low illuminating source, a tunable mode-locked Ti:Sapphire femtosecond pulse laser source, with center wavelength of 830 nm. A matching length of single- mode optical fiber wrapped around a piezoelectric modulator is placed in the reference arm for phase modulation. The properties and experimental results of our OCT system are analyzed. We got cross-sectional images of animal tissue samples. The OCT image of a mouse nephridium cortex tissue is agreed with the histological images. On the other hand, mouse brain (animal model of cerebral embolism) pathological changes tissue and normal tissue can be discriminated. The blood rheology characteristic of brain blood vessel block is discussed. It shows that this technique holds promise as a potential tool for the tissue diagnosis.

Optical coherence tomography (OCT) takes the advantage of the low coherence property of a light source to get the image of biological tissue structures 1,2 . It provides important information on the contour and thickness of tissue structures, which can be of great help for clinical diagnostic procedures. Usually, the resolution of OCT image ranges from 2 to 20 microns. At the beginning of tissue pathologic changes, the foci could be located with OCT and cured in time. In this paper, some images of rabbit' femoral artery wall taken by our OCT system are presented. From these pictures, the three-layered structure coincides with the atlas well. In addition, the image of femoral artery wall with fat deposit is shown and the tunica media is thicker than that of normal vessel wall. The ability of OCT to image tissue microstructure near the cellular level make it potential for minimally invasive probing of tissue disease. The high resolution of OCT, which is greater than any other conventional clinic imaging modality, and based on fiber, makes it particularly attractive for the assessment of early cardiovascular plaque 3 .

Monte Carlo (MC) method is employed to simulate optical path-length-resolved reflectance from samples in optical coherence tomography (OCT). Four different models are often used in such simulations to treat the scattering and absorption process. This paper presents a detailed probability analysis on the equivalence of the four different models under certain conditions. We found that the photon's statistical contributions after the same times of scattering are equal in these four models.

Optical coherence tomography (OCT) is a new noninvasive tomographic imaging techniques with resolution of micron scale. It has high potential for the application in many fields such as medicine, biology, material and so no. In this paper, our OCT system is shown to be successful in the study of both botanic and creatural tissue imaging. Furthermore we also use the Monte-Carlo simulation method to analyze 2D OCT image. The differences between single scattered light and multiply scattered light and also its influence on the quality of OCT image are discussed. To show an example, a conduit immersing in a high scattering medium as the model of blood vessel is simulated and the theoretical result is directly shown in the form of image. The conduit immersing in the high scattering medium can be clearly seen in the imags. Comparing with the experimental image they are basically accordant. Some results helpful for experimental research area draw through the simulation. To further enhance the resolution of OCT imaging, computer processing and image deconvolution are introduced. The depth resolution is improved by more than one order for the sample image and thus enables intracellular imaging.

Utilizing the ultra-fast laser or superluminescence diode (SLD) as the light source, optical coherence tomography (OCT) is a new tomographic imaging technique. It has great applying foreground in many fields such as medicine, biology, material and so on. We founded an OCT system and applied it in biological imaging successfully. Furthermore, we found a potential great application for this technique in measuring the inner structure of bedded samples such as paint films. The experiment in OCT has made prompt development, while only a little work has been done on the theoretical analysis. Some experimental results, thus, can't be explained clearly. In this paper, we use the Monte-Carlo simulation method to analyze OCT image. The differences between single scattered (or least scattered) light and multiply scattered light and its influence to the quality of OCT image are discussed in detail. To show an example, our simulating calculation object is a conduit immersing in a high scattering medium that can be regarded as the approximation of blood vessel. After programming and calculating we get the theoretical result as the form of pseudo color image. The images of conduit immersing in the high scattering medium are clearly seen. Comparing with the experimental imaging of vein they are accordant basically. All above prove the Monte-Carlo simulation method correct and effective in theoretical research of OCT. Many significant results, which are very helpful for experimental research, are draw through this method.

The autoionization distribution of the double Rydberg (DR) states N'L' nl(N'