Automatic identification of discrete substates in proteins: singular value decomposition analysis of time-averaged crystallographic refinements.

The singular value decomposition (SVD) provides a method for decomposing a molecular dynamics trajectory into fundamental modes of atomic motion. The right singular vectors are projections of the protein conformations onto these modes showing the protein motion in a generalized low-dimensional basis. Statistical analysis of the right singular vectors can be used to classify discrete configurational substates in the protein. The configuration space portraits formed from the right singular vectors can also be used to visualize complex high-dimensional motion and to examine the extent of configuration space sampling by the simulation.

The effect of tetracycline on the incidence of postextraction alveolar osteitis.

Four hundred twenty-four mandibular third molar extractions of varied surgical difficulty were evaluated for the occurrence of alveolar osteitis. In 219 of these sockets, tetracycline powder was placed immediately after the tooth was removed. This resulted in a significant reduction in the incidence of alveolar osteitis from 28.7% to 14.6%. There was also a positive correlation between the rate of alveolar osteitis and the increasing depth of the impaction and the degree of surgical difficulty.

Facial growth after condylectomy or ostectomy in the mandibular ramus.

A study was conducted in six young and six adult monkeys to determine how the condyle influences growth of the mandible. Either an ostectomy in the ramus to decrease condylar height or a condylectomy was performed on each monkey. Similar morphologic changes were observed in the maxilla and the mandible of both groups, indicating that the changes resulted from ramal shortening and alterations in function rather than from loss of a condylar growth center.