Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising in the digest tract. It brings a challenge to diagnosis because it is asymptomatic clinically. It is well known that tumor development is often accompanied by the changes in the morphology of collagen fibers. Nowadays, an emerging optical imaging technique, second-harmonic generation (SHG), can directly identify collagen fibers without staining due to its noncentrosymmetric properties. Therefore, in this study, we attempt to assess the feasibility of SHG imaging for detecting GISTs by monitoring the morphological changes of collagen fibers in tumor microenvironment. We found that collagen alterations occurred obviously in the GISTs by comparing with normal tissues, and furthermore, two morphological features from SHG images were extracted to quantitatively assess the morphological difference of collagen fibers between normal muscular layer and GISTs by means of automated image analysis. Quantitative analyses show a significant difference in the two collagen features. This study demonstrates the potential of SHG imaging as an adjunctive diagnostic tool for label-free identification of GISTs.

The tumor microenvironment (TME) is now recognized as an important participant of tumor progression. As the most abundant extracellular matrix component in TME, collagen plays an important role in tumor development. The imaging study of collagen morphological feature in TME is of great significance for understanding the state of tumor. Multiphoton microscopy (MPM), based on second harmonic generation (SHG) and two-photon excitation fluorescence (TPEF), can be used to monitor the morphological changes of biological tissues without labeling. In this study, we used MPM for large-scale imaging of early invasive breast cancer from the tumor center to normal tissues far from the tumor. We found that there were significant differences in collagen morphology between breast cancer tumor boundary, near tumor transition region and normal tissues far from the tumor. Furthermore, the morphological feature of eight collagen fibers was extracted to quantify the variation trend of collagen in three regions. These results may provide a new perspective for the optimal negative margin width of breast-conserving surgery and the understanding of tumor metastasis.

为了优化非晶合金与晶体金属的激光焊接工艺, 运用最大平均功率300 W脉冲红外激光焊接锆基非晶合金Zr57Nb5Cu15.4Ni12.6Al10与440、304、17-4PH不锈钢。采用材料分析手段和力学测试方法对实验焊接接头的材料微观组织、成分组成以及力学性能进行了表征, 取得了合适的激光偏移量焊接工艺参数、焊接接头微观组织特性数据及其力学性能数据。结果表明, 激光焦点往不锈钢侧偏移0.2 mm~0.3 mm可以使焊接熔化均匀并有效提高抗弯强度, 通过合适的焊接工艺使非晶合金与17-4PH接头抗弯强度达339 MPa; 非晶合金与3种不锈钢的激光焊接接头主要分为熔化混合区与热影响区, 熔化混合区中发现了呈树枝状与颗粒状的结晶组织, 焊后通过低温退火可使抗弯强度提升14%~48%。此研究结果对扩大锆基非晶合金在各个领域的应用具有指导意义。

为了掌握Ⅲ族氮化物微观结构对热力学性能的影响规律, 进而为超高功率器件的设计提供数据支持, 本文借助第一性原理计算软件CASTEP, 对半导体AlxGa1-xN不同合金结构及其热性能进行了系统研究。结构优化和数据分析后发现, AlxGa1-xN的晶格常数、平均键长和晶格热容值随Al组分值x(原子数分数)增大而线性减小。热力学性质计算结果表明, 在GaN中引入Al组分会在频率带隙中引入杂质模, 随着Al组分浓度的增加杂质模变宽并进入低频段, 在低频段顶部频率随Al组分增大而线性升高, 在12.5%以上低频段顶部频率均大于 (1/2)A1(LO)。温度从300 K到700 K变化时, 合金热容随温度变化关系结果证明, 在确定温度时, AlxGa1-xN合金热容随Al组分增大而线性减小。本文的研究为以AlxGa1-xN为代表的Ⅲ族氮化物半导体高功率器件设计提供了一定的设计参考。

针对三维纤维微观结构方向检测的不足,提出一种基于facet模型的三维纤维方向检测方法。该方法将三维纤维方向检测转换为二维平面检测,能够降低计算的复杂度,通过facet模型实现了不同直径纤维方向的精确检测,模型窗口尺寸略大于纤维直径时能达到最优结果。实验结果表明,所提方法可快速准确地获取不同直径的三维纤维方向数据,优于现有的典型算法。

多光子显微(MPM)技术通过探测由飞秒激光与生物组织内在成分相互作用而产生的双光子激发荧光和二次谐波等光信号，可实现对组织的无损、非标记成像。MPM具有对组织微结构灵敏度度和可实现高空间分辨成像、对生物组织杀伤性低和成像深度深、能够获取组织的生化信息等优点，在疾病诊断中具有很大的应用潜力。简要介绍MPM的基本原理，总结其在消化道肿瘤、皮肤疾病，以及角膜疾病诊断中的应用，并对MPM的发展前景进行展望。

Precisely distinguishing between hyperplastic and adenomatous polyps and normal human colonic mucosa at the cellular level is of great medical significance. In this work, multiphoton laser scanning microscopy (MPLSM) was used to obtain the high-contrast images and the morphological characteristics from normal colonic mucosa, hyperplastic polyps and tubular adenoma. By integrating the length and area measurement tools and computing tool, we quantified the difference of crypt morphology and the alteration of nuclei in normal and diseased human colonic mucosa. Our results demonstrated that the morphology of crypts had an obvious tendency to cystic dilatation or elongated in hyperplastic polyps and tubular adenoma. The content and number of mucin droplets of the scattered goblet cells had a piecemeal reduction in hyperplastic polyps and a large decrease in tubular adenoma. The nuclei of epithelial cells might be elongated and pseudostratified, but overt dysplasia was absent in hyperplastic polyps. Nevertheless, the nuclei showed enlarged, crowded, stratified and a rod-like structure, with loss of polarity in tubular adenoma. These results suggest that MPLSM has the capacity to distinguish between hyperplastic and adenomatous polyps and normal human colonic mucosa at the cellular level.