objectives : cleaning and shaping of the root canal system is an important step in endodontic therapy. new instruments incorporate new preparation techniques that can improve the efficacy of cleaning and shaping. the aim of this study was to compare the efficacy of mtwo and race rotary file systems in straightening the canal curvature using only one file or the conventional method. materials an...

A 27-year-old Hispanic female, in second trimester of her pregnancy, presented to our emergency department (ER) with gradually worsening shortness of breath. The physical exam was significant for a loud S1, mid-diastolic murmur of mitral stenosis and basilar crackles. A chest X-ray was performed that showed bilateral pulmonary edema and straightening of the left heart border (Figure 1). The ech...

The L1Hs preTa subfamily of long interspersed elements (LINEs) originated after the divergence of human and chimpanzee and is therefore found only in the human genome. Thirty-three of the 254 L1Hs preTa elements are polymorphic for the absence/presence of the insertion, making them useful markers for studying human population genetics. The problem of homoplasy, however, can diminish the value o...

Helical ribbons with pitch angles of either 11 degrees or 54 degrees self-assemble in a wide variety of quaternary surfactant-phospholipid/fatty acid-sterol-water systems. By elastically deforming these helices, we examined their response to uniaxial forces. Under sufficient tension, a low pitch helix reversibly separates into a straight domain with a pitch angle of 90 degrees and a helical dom...