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Background: Gastric cancer is one of the most common malignancies that pose a serious risk to human health worldwide. Lymph node metastasis may serve as an important prognostic factor for gastric cancer. However, the use of lymph nodes as a prognostic indicator for gastric cancer may lead to stage migration. The aim of this study is to establish a nomogram model to increase the prognostic accuracy of gastric cancer by validating the prognostic role of lymph node metastatic risk. Methods: A total of 3716 patients with gastric cancer were included in this study based on information from the SEER database. The risk factors for lymph node metastasis were analyzed correlatively. Prognostic factors were analyzed by COX regression, on which nomograms were constructed. The model was validated with ROC and C-indices, and Kaplan-Meier curves were evaluated and analyzed for each prognostic factor. Results: Age, sex, T-stage, N-stage, M-stage, tumor size and lymph node ratios all served as independent prognostic factors for gastric cancer. lymph node metastasis ratio is a prognostic factor in gastric cancer that is superior to lymph node number. The nomogram model has 3- and 5-year AUC values of 0.797 and 0.817 respectively, with a C-index of 0.730. Conclusion: As a prognostic factor of gastric cancer, lymph node metastasis ratio can reduce stage migration, and its inclusion in the nomogram model is superior to the TNM staging system to evaluate the prognosis of gastric cancer. The nomogram model we have developed has high reliability and accuracy and thus can inform personalized clinical treatment for gastric cancer patients.

In the process of orthodontics, accurate bracket positioning is a necessary condition to quickly obtain the ideal treatment result. We propose a virtual bracket-interaction method based on the Layered Depth-Normal Images (LDNI) and the point set matching. By means of mouse-interaction, the fast movement of the bracket on the tooth surface is realized. Specifically, LDNI is used to complete the sampling of the bottom point of the bracket in space coordinate system. Then the nearest-distance algorithm is used to find the corresponding point on the tooth surface. Finally, the position of the bracket on the tooth surface is determined by point set matching. In addition, in order to help the orthodontist to complete clinical correction, we design a virtual bracket interaction software to realize the positioning operation of the virtual bracket through mouse interaction. The results demonstrates that the software we developed is very helpful for orthodontists to complete bracket positioning.

This thesis describes a hand-held confocal optical scanner for cellular imaging. In current clinical practice, the detection of disease like colorectal cancer is performed using endoscopy and biopsy. Random biopsies and oversampling are usually required to reduce false results, so potentials exist for non-invasive optical diagnostic techniques. Optical microscopy techniques such as confocal laser scanning microscopy provide images for biological tissues at a micrometer level. The challenge is to miniaturize the system into a form of hand-held devices or catheters. The developed system in this thesis consists of a portable scanner probe and a reflectance confocal imaging unit. The imaging unit was constructed in an all-fiber configuration for convenient packaging. Confocal scanning was performed at 785 nm laser illumination with a piezoelectric fiber scanner probe. The fiber-based probe was constructed by mounting a fiber directly on a two-dimensional piezoelectric bender. Horizontal image scanning has been successfully achieved, and the developed device can provide image resolution of 1.16-1.41 μm in the lateral direction and can resolve cell structures. The operating scanning speed is 1.25 frames per second with 88 × 88 μm² field of view, potentially applicable to real-time imaging. Image results were presented with onion epidermis and optical paper samples in comparison to galvanometer mirrors based confocal laser scanning unit.

The influence of Sr addition on pore formation in directionally solidified Al-12.3wt.% alloy was investigated using X-ray detection, optical microscope, and SEM-EDX. Results indicate that addition of Sr significantly increases the number density and volume fraction of porosity. The considerable rise in volume fraction of porosity is attributed to the remarkable increase in the numbers of pores formed. It is found that Sr solute in liquid Al-Si alloy can diffuse into the oxide inclusions to form loose oxide aggregations which have more activity as the nucleation sites for porosity. Adding more Sr considerably increases the numbers of active nucleation sites. There is an obvious fluctuation of pore number density during steady state solidification, which is believed to be related to a fluctuation of local hydrogen supersaturation induced by the competition of pore nucleation and growth for hydrogen solute supplement.

Hole filling of teeth and gums is an essential stage in orthodontics after segmentation. The patching mesh should keep the morphological features of generic teeth and gums while avoiding collision between two adjacent teeth. This paper presents an efficient hole-filling algorithm to reconstruct the missing part of teeth and gums. Our proposed method involves four necessary steps: boundary construction and projection, hole triangulation in 2D, back projection of vertices to 3D, and mesh fairing. By combining constrained Delaunay triangulation in 2D with back projection of vertices to 3D using mean value coordinates, we achieve high robustness of hole triangulation and a high-quality initial patching mesh. In addition, we propose an automatic method to control the deformation degree to avoid collision. Our experiments demonstrate that the proposed method can achieve satisfactory results, not only in morphology, but also in efficiency. The results are very similar to real teeth and gums and can meet the requirements of orthodontics in medicine.

The Oriental planthopper genus Gelastyrella Yang is reviewed. Two new species, G.. hainanensis Ran et Liang, sp. nov. (China: Hainan) and G.. yunnanensis Ran et Liang, sp. nov. (China: Yunnan), are described and illustrated. A key to the species of the genus is provided.