Ray tracing method in arbitrarily shaped radial graded-index waveguide.

A ray tracing algorithm for an arbitrarily shaped axially symmetric graded index waveguide was proposed. This was achieved by considering the center of the waveguide (optical axis) as a set of discrete points. The refractive index depends on the distance of the ray position from the optical axis.

Endometrioid adenocarcinoma arising from endometriosis of the rectosigmoid.

A case of endometrioid adenocarcinoma supposedly arising from endometriosis of the rectum is reported. Malignant transformation is uncommon but a well-known complication of endometriosis. In the present case, it was proved by histopathological findings and immunophenotype such as cytokeratin7+/cytokeratin20-/estrogen receptor+.

A Case of Malignant T-Cell Lymphoma of Gastric Origin Accompanied by Pyothorax.

The patient was a 74-year-old man suffering from tuberculotic chronic pyothorax. He had hematemesis in January 2006. Hb was 6.

[Two cases of gastrointestinal stromal tumor (GIST) of the stomach and a consideration of its malignancy potential and treatment strategy - report of two cases].

We report two cases of large gastrointestinal stromal tumor (GIST) of the stomach both of which were assessed as highly malignant, but took different clinical courses. Case 1: A 72-year-old male. Case 2: A 63-year-old female.