Nacre is an exquisitely structured biocomposite of the calcium carbonate mineral aragonite with small amounts of proteins and the polysaccharide chitin. For many years, it has been the subject of research, not just because of its beauty, but also to discover how nature can produce such a superior product with excellent mechanical properties from such relatively weak raw materials. Four decades ...

Remodeling of uterine spiral arteries is critical for the continuation of a successful pregnancy. Uterine natural killer (uNK) cells are the predominant leukocyte population in the early pregnant decidua, and a role for these cells in spiral artery remodeling in pregnancy has been suggested. Angiogenic growth factors were measured in isolated uNK and total (unseparated) decidual cells (8-10 or ...

Geometrical design of the spiral crystal selector can affect crystal orientation in the final single crystal structure. To achieve a better understanding of conditions associated with the onset of crystal orientation in a spiral crystal selector, temperature field was investigated using three-dimensional finite element method during the process. Different geometries of spiral crystal selec...

We investigate the formation of substructure in spiral galaxies using global MHD simulations, including gas self-gravity. Local modeling by Kim and Ostriker (2002) previously showed that self-gravity and magnetic fields cause rapid growth of overdensities in spiral arms; differential compression of gas flowing through the arms then results in formation of sheared structures in the interarms. Th...

Menorrhagia affects approximately 15% of all women, often without identifiable cause. Endometrial spiral arterioles are believed to play a major role in controlling menstruation, and are a major site of menstrual loss. We postulate that alterations in the growth and development of spiral arterioles, particularly the vascular smooth muscle cells (VSMC), may contribute to menorrhagia. We examined...

OBJECTIVE To identify the expression of netrin-1, a diffusible chemoattractive molecule, and its receptor, deleted in colorectal carcinoma (DCC), in the developmentally mature inner ear, and to determine its effects on axon length and guidance in cultured auditory neurons. DESIGN Messenger RNA (mRNA) and protein expression of netrin-1 and DCC were identified in the organ of Corti and spiral g...

Esophageal Development. 1. The region of most active mitosis per mm. of cross-section in the esophagus is the entodermal epithelial tube. The mitotic figures follow a spiral path in the manner of a left-handed helix from the cephalic to the caudal direction. 2. The region of least active growth per mm. of cross-section in the esophagus is the mesenchyme surrounding the epithelial tube. 3. The h...