United States Code

About: United States Code is a based out in . It is known for research contribution in the topics: Population & Supersymmetry. The organization has 318 authors who have published 231 publications receiving 7341 citations. The organization is also known as: Code of Laws of the United States of America & U.S. Code.

Msx2 deficiency in mice causes pleiotropic defects in bone growth and ectodermal organ formation.

Abstract: The composite structure of the mammalian skull, which forms predominantly via intramembranous ossification, requires precise pre- and post-natal growth regulation of individual calvarial elements. Disturbances of this process frequently cause severe clinical manifestations in humans. Enhanced DNA binding by a mutant MSX2 homeodomain results in a gain of function and produces craniosynostosis in humans. Here we show that Msx2-deficient mice have defects of skull ossification and persistent calvarial foramen. This phenotype results from defective proliferation of osteoprogenitors at the osteogenic front during calvarial morphogenesis, and closely resembles that associated with human MSX2 haploinsufficiency in parietal foramina (PFM). Msx2-/- mice also have defects in endochondral bone formation. In the axial and appendicular skeleton, post-natal deficits in Pth/Pthrp receptor (Pthr) signalling and in expression of marker genes for bone differentiation indicate that Msx2 is required for both chondrogenesis and osteogenesis. Consistent with phenotypes associated with PFM, Msx2-mutant mice also display defective tooth, hair follicle and mammary gland development, and seizures, the latter accompanied by abnormal development of the cerebellum. Most Msx2-mutant phenotypes, including calvarial defects, are enhanced by genetic combination with Msx1 loss of function, indicating that Msx gene dosage can modify expression of the PFM phenotype. Our results provide a developmental basis for PFM and demonstrate that Msx2 is essential at multiple sites during organogenesis.

Endoscopic ligation compared with sclerotherapy for the treatment of bleeding esophageal varices

Abstract: Objective: Comparison of the safety and efficacy of endoscopic sclerotherapy and ligation for the treatment of bleeding esophageal varices. Design: Randomized, controlled trial. Setting: An urban c...

Microstructural characteristics of ultrafine-grained aluminum produced using equal-channel angular pressing

Abstract: The shearing associated with equal-channel angular (ECA) pressing was examined using optical microscopy. Samples of pure Al with a large grain size were subjected to ECA pressing to different strains and then examined on three orthogonal planes. Samples were pressed without any rotation or with rotations of either 90 or 180 deg between each consecutive pressing. The experimental observations are compared with models which predict the shearing characteristics associated with ECA pressing under different conditions. It is demonstrated that there is good agreement, in terms of both the grain elongation and the shearing within individual grains, between the experimental results and the predictions of the models.