Catalog of Galactic Beta Cephei Stars

We present an extensive and up-to-date catalog of Galactic Beta Cephei stars. This catalog is intended to give a comprehensive overview of observational characteristics of all known Beta Cephei stars. 93 stars could be confirmed to be Beta Cephei stars. For some stars we re-analyzed published data or conducted our own analyses. 61 stars were rejected from the final Beta Cephei list, and 77 stars are suspected to be Beta Cephei stars. A list of critically selected pulsation frequencies for confirmed Beta Cephei stars is also presented. We analyze the Beta Cephei stars as a group, such as the distributions of their spectral types, projected rotational velocities, radial velocities, pulsation periods, and Galactic coordinates. We confirm that the majority of these stars are multiperiodic pulsators. We show that, besides two exceptions, the Beta Cephei stars with high pulsation amplitudes are slow rotators. We construct a theoretical HR diagram that suggests that almost all 93 Beta Cephei stars are MS objects. We discuss the observational boundaries of Beta Cephei pulsation and their physical parameters. We corroborate that the excited pulsation modes are near to the radial fundamental mode in frequency and we show that the mass distribution of the stars peaks at 12 solar masses. We point out that the theoretical instability strip of the Beta Cephei stars is filled neither at the cool nor at the hot end and attempt to explain this observation

The Normal Biopsy: Colonic and Ileal Mucosa and Submucosa

The digestive tract is a hollow tube consisting throughout of three coats or layers. The first layer, the mucosa, is made up of an epithelial lining which borders on the lumen of the bowel and rests upon a basement membrane, the lamina propria and the muscularis mucosae. The mucosa of the colon has a smooth surface and is composed of tubular parallel crypts embedded in a loosely arranged stroma. The mucosa of the ileum is composed of fingerlike villi and displays a number of specific features including the shorter villi and more epithelial goblet cells on the surface than the proximal small intestine and the presence of Peyer’s patches. The second coat is the submucosa. The muscularis propria, the third layer, is composed of two layers of smooth muscle separated by a thin layer of connective tissue in which the ganglionated myenteric plexus (Auerbach’s) can be observed. The subserosa is composed of loose areolar tissue covered by mesothelium where the tract borders on the body cavity (serosa). Endoscopic biopsies are limited to the mucosa and upper part of the submucosa. A good understanding of the normal histology of the mucosa and submucosa is essential for analysis of endoscopic biopsies of the ileum and the colon