共查询到20条相似文献,搜索用时 562 毫秒
1.
We consider the effect of laser-induced in vivo photodissociation of blood oxyhemoglobin on gas exchange in biological tissues.
An optical method of laser-induced oxygenation of biotissues is developed and proposed. We show that, in the region of the
action of the laser radiation, the degree of oxygenation of a tissue increases. We experimentally confirm that the phenomenon
of laser-induced in vivo photodissociation of oxyhemoglobin opens up a new possibility of controlling the local concentration
of free molecular oxygen in tissues, eliminating tissue hypoxia, and stimulating aerobic metabolism of cells. We show that
the efficiency of the proposed method of laser-induced oxygenation of biotissues proves to be comparable with the efficiency
of the hyperbaric oxygenation, but has the advantage of the locality of the action. The proposed optical method of local oxygenation
of biotissues will make it possible to eliminate the problem of hypoxia in cancerous tumor tissue and to considerably increase
the efficiency of photodynamic, radiation, and chemotherapy in modern oncology. 相似文献
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We propose and examine a new approach to visualizing a local network of cutaneous blood vessels using laser optical methods
for applications in biometry and photomedicine. Various optical schemes of the formation of biometrical information on the
architecture of blood vessels of skin tissue are analyzed. We developed an optical model of the interaction of the laser radiation
with the biological tissue and a mathematical algorithm of processing of measurement results. We show that, in medicine, the
visualization of blood vessels makes it possible to calculate and determine regions of disturbance of blood microcirculation
and to control tissue hypoxia, as well as to maintain the local concentration of oxygen at a level necessary for the normal
cellular metabolism. We propose noninvasive optical methods for modern photomedicine and biometry for diagnostics and elimination
of tissue hypoxia and for personality identification and verification via the pattern of cutaneous blood vessels. 相似文献
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Diffuse reflection spectra of biotissues in vivo and transmission and reflection coefficients for biotissues in vitro are
measured over 300–800 nm. These data are used to determine the spectral absorption and scattering indices and the scattering
anisotropy factor for stomach mucous membranes under normal and various pathological conditions (chronic atrophic and ulcerous
defects, malignant neoplasms). The most importan tphysiological (hemodynamic and oxygenation levels) and structural-morphological
(scatterer size and density) parameters are also determined. The results of a morphofunctional study correlate well with the
optical properties and are consistent with data from a histomorphological analysis of the corresponding tissues. 相似文献
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P. D. Agrba M. Yu. Kirillin A. I. Abelevich E. V. Zagaynova V. A. Kamensky 《Optics and Spectroscopy》2009,107(6):853-858
The efficiency of the mechanical compression of biotissues for improving the differentiation between pathological changes
in the structure of a biotissue observed by the method of optical coherence tomography (OCT) is investigated. The effect of
the compression in the OCT-images of samples of the human rectum affected by inflammation and carcinoma is studied ex vivo.
It is shown that the use of compression makes it possible to differentiate between these pathological changes. To interpret
experimental data, images of an inflamed part of rectum are modeled by the Monte Carlo method for different degrees of compression.
The results of modeling agree qualitatively with the experimental data. 相似文献
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V. S. Letokhov 《Il Nuovo Cimento D》1991,13(7):939-948
Summary A new laser method for the spectroscopy of locally absorbing microvolumes much smaller than the radiation wavelength in size
is discussed. Such an absorption is characteristic of biotissues and other biological media. The method allows data to be
obtained on the size of local microvolumes absorbing at the radiation wavelength. It is based on the possibility of transient
overheating of the microvolumes by means of an ultrashort pulse with a duration much shorter than the time it takes to heat
to diffuse from the microvolumes. The pulse-heated microvolumes must have an altered refractive index leading to an additional
scatter of another probe laser pulse, that is made to irradiate the medium under study after some delay. Besides, the locally
heated microvolumes will have temperature-altered fluorescence induced either by the heating laser pulse or by an additional
probe pulse at another wavelength more suitable for fluorescence excitation.
Due to the relevance of its scientific content, this paper has been given priority by the Journal Direction. 相似文献
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A single diffractive optical element implementing spectrum-splitting and beam-concentration functions simultaneously with high diffraction efficiency 下载免费PDF全文
In this paper,a novel method is proposed and employed to design a single diffractive optical element(DOE) for implementing spectrum-splitting and beam-concentration(SSBC) functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modern photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems. 相似文献
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A method for computer modeling of transmission and diffuse reflection of a strongly scattering biotissue is described. Results of calculations of spectral characteristics for a model of the human eye sclera are presented and compared with experiments. The possibility to control optical properties of biotissues is theoretically substantiated and experimentally confirmed. Variations in color indices of biotissues are calculated using theoretical and experimental spectral characteristics obtained for the eye sclera. 相似文献
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利用近红外光谱检测多层组织血氧饱和度的研究 总被引:2,自引:0,他引:2
利用近红外光谱无创检测生物组织血氧饱和状态,是一种极富研究和应用前景的检测技术,在临床检测中被广泛应用.但常规临床检测应用于指端仅反映局部血氧饱和度信息,在使用中具有局限性,信号的可信度也存在质疑.该文提出了一种采用反射式脉搏血氧饱和度检测技术检测生物多层组织氧合状况的新方法,该方法通过调节入射光强以适应解剖学中生物组织多层结构的检测.应用该方法针对手指结构的实验结果表明,随着入射光强的改变,反映血氧饱和状态的光电脉搏波信号有显著变化.结合手指解剖学分析表明,光电脉搏波信号的变化与手指的多层面组织结构相对应,反映不同层面血氧饱和状态.这一特点表明,通过此法可以针对生物组织的多层结构进行测量. 相似文献
10.
A new method is studied for estimating the hemoglobin concentration and oxygenation of a local blood layer in a human skin tissue model on the basis of visible and near infrared reflectance spectra. This method uses the iterative Monte Carlo technique for a multi-layered skin tissue model. The numerical simulation was performed to investigate the effects of estimation errors for epidermis and dermis layers on the results for the local blood layer. Experiments with skin tissue phantoms were performed to verify the possibility of this method. 相似文献
11.
Structures that can be interpreted as cytoplasm droplets leaking through the membrane are experimentally detected on the membranes of adipocytes using optical digital microscopy. The effect of an aqueous alcohol solution of brilliant green on the amount and sizes of structures is studied. It is demonstrated that the optical irradiation of the adipocytes that are sensitized with the aid of the brilliant green leads to an increase in the amount of structures (pores) after the irradiation. The experimental results confirm the existence of an earlier-proposed effect of photochemical action on the sensitized cells of adipose tissue that involves additional formation of pores in the membrane of the sensitized cell under selective optical irradiation. The proposed method for the detection of micropores in the membrane of adipose tissue based on the detection of the cytoplasm droplets leaking from the cell can be considered as a method for the optical detection of nanosized pores. 相似文献
12.
We demonstrate the capability of differential path-length spectroscopy (DPS) to determine the local optical properties of tissue in vivo. DPS measurements on bronchial mucosa are analyzed and yield information on the local blood oxygenation, blood content, average microvessel diameter, and wavelength dependence of the reduced scattering coefficient. Our data collected to date show that cancerous bronchial mucosa has a lower capillary oxygenation and a larger average capillary diameter than normal bronchial mucosa. 相似文献
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基于光子晶体的自准直效应和禁带特性,提出了一种具有非正交异质结结构的光子晶体偏振分束器.无需引入缺陷或波导,可使光波在该结构中准直无发散地传输并实现分束功能,对制造工艺的要求大大降低.利用Rsoft软件,结合平面波展开法和二维时域有限差分法,对提出的偏振分束器进行了仿真研究.结果表明,该偏振分束器在一个较大的频率范围f=0.275—0.285(a/λ)内可实现横电(TE)和横磁(TM)模的大角度偏振分离,TE和TM模的透过率均在88%以上,偏振消光比分别大于26.57 dB和17.50 dB.该结构可应用到太赫兹波段的传输系统中,a=26μm,尺寸大小为572μm×546μm,在91—95μm波长范围内可实现TE和TM模的分离.利用该结构可设计用于光通信系统(n=3.48)的偏振分束器,a=426.25 nm,结构仅为9.38μm×8.95μm.本方案结构简单,易于集成,有望在集成光路的发展中发挥重要作用. 相似文献
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近红外空间分辨光谱技术及其对新生猪脑缺氧缺血的检测 总被引:2,自引:0,他引:2
近红外光谱(NIRS)技术作为一种无创的组织氧检测手段,近年来在脑缺氧缺血的检测方面日益受到重视。文章介绍了自行研制的NIRS仪器(TSAH-100近红外组织血氧无损监测仪)的基本原理及用于新生猪脑氧检测时如何实现传感器与待测脑组织的最佳耦合。检测了28例新生猪在不同氧合状态下的脑组织氧饱和度(regional cerebral oxygen saturation, rSO2),在缺氧结束后进行了有创的动脉氧饱和度及生理参数的检测。结果表明,NIRS无创测得的脑rSO2与血气分析有创测得的动脉血氧饱和度(SaO2)有很好的相关性(p<0.001),并且脑rSO2与缺氧程度及缺氧后生理参数的变化一致。因此NIRS无创测得的脑rSO2能直接判断脑氧合状态,可在一定情况下替代有创血气分析,帮助临床无创、简便地诊断脑缺氧缺血。 相似文献
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激光切割相对冲压及线切割工艺具有自由度大、加工效率高、不会影响铁心质量等优点,但由于残渣及切口粗糙问题一定程度上影响了激光切割硅钢片的质量和应用范围.通过采用在工件底部增设辅助侧吹喷嘴,控制熔渣流向,保证成品切割质量激光切割工艺,试验证明,合理控制工艺参量,可获得良好效果.利用有限元法进一步对工件底部气流状况进行了数值模拟,分析了流动过程中在不同的角度和流速下光斑移动和气流场变化的情况,初步确定工件底部侧吹气流以20°吹入的辅助侧吹工艺,为进一步合理控制熔渣流向获得光滑的精细切口提供了实践和理论依据. 相似文献