A Consensus Modeling Approach for the Determination of Stratum Corneum Thickness Using In-Vivo Confocal Raman Spectroscopy

The measurement of stratum corneum (SC) thickness from in-vivo Raman water concentration depth profiles is gaining in popularity and appeal due to the availability and ease of use of in-vivo confocal Raman measurement systems. The foundation of these measurements relies on high-quality confocal Raman spectroscopy of skin and the robust numerical analysis of water profiles, which allow for accurate determination of SC thickness. These measurements are useful for studying intrinsic skin hydration profiles at different body sites and for determining hydration properties of skin related to topically applied materials. While the use of high-quality in-vivo Raman instrumentation has become routine and its use for SC thickness measurement widely reported, there is lack of agreement as to the best method of computing SC thickness values from Raman water profiles. Several methods have been proposed and are currently in use for such computations, but none of these methods has been critically evaluated. The work reported in this paper describes a new method for the determination of stratum corneum thickness from in-vivo confocal Raman water profiles. The method represents a consensus approach to the problem, which was found necessary to apply in order to properly model and quantify the large diversity of water profile types encountered in typical in-vivo Raman water measurement. The methodology is evaluated for performance using three criteria: 1) frequency of minimum fitting error on modeling to a standard numerical function;2) frequency of minimum model error for consensus vs. individual SC thickness values;and 3) correlation with reflectance confocal microscopy (RCM) values for SC thickness. The correlation study shows this approach to be a reasonable replacement for the more tedious and time-consuming RCM method with R2 = 0.68 and RMS error = 3.7 microns over the three body sites tested (cheek, forearm and leg).

Theoretical investigation on Raman induced Kerr effect spectroscopy in nonlinear confocal microscopy

The imaging theory of Raman induced Kerr effect spectroscopy (RIKES) in nonlinear confocal microscopy is presented in this paper. Three-dimensional point spread function (3D-PSF) of RIKES nonlinear confocal microscopy in isotropic media is derived with Fourier imaging theory and RIKES theory. The impact of nonlinear property of RIKES on the spatial resolution and imaging properties of confocal microscopy have been analyzed in detail. It is proved that RIKES nonlinear confocal microscopy can simultaneously provide more information than two-photon confocal microscopy concerning molecular vibration mode, vibration orientation and optically induced molecular reorientation, etc. It is shown that RIKES nonlinear confocal microscopy significantly enhances the spatial resolution and imaging quality of confocal microscopy and achieves much higher resolution than that of two-photon confocal microscopy.

Confocal photoluminescence characterization of silicon-vacancy color centers in 4H-SiC fabricated by a femtosecond laser

Silicon-vacancy(VSi)centers in silicon carbide(SiC)are expected to serve as solid qubits,which can be used in quantum computing and sensing.As a new controllable color center fabrication method,femtosecond(fs)laserwriting has been gradually applied in the preparation of VSi in SiC.In this study,4H-SiCwas directlywritten by an fs laser and characterized at 293 K by atomic force microscopy,confocal photoluminescence(PL),and Raman spectroscopy.PL signals of VSi were found and analyzed using 785 nm laser excitation by means of depth profiling and two-dimensional mapping.The influence of machining parameters on the VSi formation was analyzed,and the three-dimensional distribution of VSi defects in the fs laser writing of 4H-SiC was established.

拉曼光谱分析盐酸曲马多的结构特征

目的通过盐酸曲马多共聚焦拉曼光谱探讨其结构特征。方法用共焦拉曼光谱仪测定盐酸曲马多拉曼光谱图。结果所测药物图谱峰形良好,峰强明显,指纹性强,能够反映出盐酸曲马多的结构信息。结论共聚焦拉曼光谱仪可用于盐酸曲马多的结构特征分析,且拉曼光谱是一种简单、灵敏的光谱分析工具,有望成为药物分析中一种有效的鉴别手段。

Photoluminescence and Raman Spectroscopy Study on Color Centers of Helium Ion-Implanted 4H-SiC

Color centers in silicon carbide(SiC)are promising candidates for quantum technologies.However,the richness of the polytype and defect configuration of SiC makes the accurate control of the types and position of defects in SiC still challenging.In this study,helium ion-implanted 4H-SiC was characterized by atomic force microscopy(AFM),confocal photoluminescence(PL),and confocal Raman spectroscopy at room temperature.PL signals of silicon vacancy were found and analyzed using 638-nm and 785-nm laser excitation by means of depth profiling and SWIFT mapping.Lattice defects(C-C bond)were detected by continuous laser excitation at 532 nm and 638 nm,respectively.PL/Raman depth profiling was helpful in revealing the three-dimensional distribution of produced defects.Differences in the depth profiling results and SRIM simulation results were explained by considering the depth resolution of the confocal measurement setup,helium bubbles,as well as swelling.

牙体组织粘接界面观察分析方法的研究进展

目前牙科粘接技术及材料以其优良的性能,已被广泛应用于口腔治疗的各个领域。为提高粘接效果,各种新型粘接技术及材料被不断研发。而粘接界面的观察分析是评估粘接效果最重要的实验室检测手段之一。本文通过对相关文献进行收集整理,筛选出目前最常用的6种牙体组织粘接界面观察方法,包括扫描电子显微镜、透射电子显微镜、激光共聚焦显微镜、拉曼光谱、光学相干层析成像、原子力显微镜。分析其特点可发现:扫描电子显微镜及透射电子显微镜多用于界面细微结构的观察;激光共聚焦显微镜、光学相干层析成像多用于微渗漏、外源性荧光、自发荧光等特征性图像信息的获取;而拉曼光谱及原子力显微镜则能对粘接界面的化学组成及机械性能进行分析。

FTIR和Raman用于盐酸曲马多的结构分析

采用AVATAR 360型傅里叶变换红外光谱仪和RM-1000型激光共聚焦拉曼光谱仪测定盐酸曲马多的红外光谱和拉曼光谱。拉曼光谱和红外光谱中均显示出了盐酸曲马多的特征峰,都能够用于其结构鉴别。采用红外、拉曼光谱这两种方法互相印证,互相补充,可增强鉴定的准确性、可靠性。

显微共聚焦拉曼光谱法检测非法添加的化学壮阳药

目的建立显微共聚焦拉曼光谱法检测中药中非法添加磷酸二酯酶5型(PDE5)抑制剂的方法。方法供试品在显微镜下微区成像,逐点选择不同的点采集拉曼光谱图,并与对照品光谱图进行比对分析,以判断是否非法添加。结果在市场监督抽样的不同种类的壮阳类中药中分别检出非法添加PDE5抑制剂西地那非及其同系物他达那非,检出结果进一步经HPLC-MS分析验证。结论显微共聚焦拉曼光谱可作为中药、保健食品中非法添加化学药物检测的可选方法。

显微共聚焦拉曼检测中药中非法添加的化学降糖药

目的:建立检测中药中非法添加化学降糖药的拉曼光谱法。方法:采用显微共聚焦拉曼光谱法,使样品在显微镜下微区成像,逐点选择不同的点采集拉曼光谱图,并与对照品光谱图进行比对分析,判断是否非法添加。结果:在市场监督抽样的中药中检出非法添加盐酸二甲双胍,检出结果进一步得到HPLC-MS法验证。结论:显微共聚焦拉曼光谱可作为中药、保健食品中非法添加化学药物检测的可选方法。