AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous colonic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application.METHODS: N...AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous colonic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application.METHODS: Normal and adenomatous colonic tissues were obtained from patients during surgery. A FL/FS920combined TCSPC spectrofluorimeter and a lifetime spectrometer system were used for fluorescence measurement.Fluorescence excitation wavelengths varying from 260 to 540 nm were used to induce the autofluorescence spectra,and the corresponding emission spectra were recorded from a range starting 20 nm above the excitation wavelength and extending to 800 nm. Emission spectra were assembled into a three-dimensional fluorescence spectroscopy and an excitation-emission matrix (EEM) to exploit endogenous fluorophores and diagnostic information. Then emission spectra of normal and adenomatous colonic tissues at certain excitation wavelengths were compared to determine the optimal excitation wavelengths for diagnosis of colonic cancer.RESULTS: When compared to normal tissues, low NAD (P)H and FAD, but high amino acids and endogenous phorphyrins of protoporphyrin Ⅸ characterized the highgrade malignant colonic tissues. The optimal excitation wavelengths for diagnosis of colonic cancer were about 340, 380, 460, and 540 nm.CONCLUSION: Significant differences in autofluorescence peaks and its intensities can be observed in normal and adenomatous colonic tissues. Autofluorescence EEMs are able to identify colonic tissues.展开更多
基金Supported by the Natural Science Foundation of Fujian Province, No. A0310018 and No. 2002F008the Scientific Research Program of Fujian Province, No. JA03041
文摘AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous colonic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application.METHODS: Normal and adenomatous colonic tissues were obtained from patients during surgery. A FL/FS920combined TCSPC spectrofluorimeter and a lifetime spectrometer system were used for fluorescence measurement.Fluorescence excitation wavelengths varying from 260 to 540 nm were used to induce the autofluorescence spectra,and the corresponding emission spectra were recorded from a range starting 20 nm above the excitation wavelength and extending to 800 nm. Emission spectra were assembled into a three-dimensional fluorescence spectroscopy and an excitation-emission matrix (EEM) to exploit endogenous fluorophores and diagnostic information. Then emission spectra of normal and adenomatous colonic tissues at certain excitation wavelengths were compared to determine the optimal excitation wavelengths for diagnosis of colonic cancer.RESULTS: When compared to normal tissues, low NAD (P)H and FAD, but high amino acids and endogenous phorphyrins of protoporphyrin Ⅸ characterized the highgrade malignant colonic tissues. The optimal excitation wavelengths for diagnosis of colonic cancer were about 340, 380, 460, and 540 nm.CONCLUSION: Significant differences in autofluorescence peaks and its intensities can be observed in normal and adenomatous colonic tissues. Autofluorescence EEMs are able to identify colonic tissues.
基金Foundation item: Project (50575220) supported by the National Natural Science Foundation of ChinaProject supported by State Key Laboratory of Engines,China
文摘在传统的热障涂层(TBCs)制备工艺的基础上,在制备热障涂层陶瓷层前,采用超音速微粒轰击技术(SFPB)改变粘结层的表面状态。采用 X 射线衍射分析仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、透射电子显微镜(TEM)和微区 Cr3+荧光光谱研究粘结层的表面结构及其 1000 °C时的高温氧化相变。粘结层表面位错密度大幅度增加,形成了大量的原子扩散通道;在高温氧化初期,粘结层中 Al 原子扩散速度的增快保证了优先形成一层稳定的α-Al2O3相;在高温氧化瞬态阶段,大量 Cr3+通过 SFPB 产生的扩散通道,形成过渡相(Al0.9Cr0.1)2O3,该过渡相间接促进了γ→θ→α相变。在高温氧化初期,热障涂层 TGO 中的残余应力先急剧增大然后减小;与高温氧化26 h 的 0.93 GPa 相比,高温氧化 310 h 的残余应力降低至 0.63 GPa。在热障涂层的 TGO 层中获得了单一、连续、致密的具有抗高温氧化能力的主相α-Al2O3,这利于进一步延长其使用寿命。
