Diffraction problems for quasilinear parabolic systems with boundary intersecting interfaces

Stability of Unilateral Posterior Crossbite Correction in the Mixed Dentition - an RCT-study with 3-year Follow-Up. Aim: To compare and evaluate long-term stability of crossbite correction with Quad Helix or expansion plate in the mixed dentition. Methods: In this RCT-study 35 patients with unilateral posterior crossbite were randomized to be treated with either Quad Helix or expansion plate. The inclusion criteria were: mixed dentition, unilateral posterior crossbite, no sucking habits or previous orthodontic treatment. Stability was evaluated after 3 years by study cast measurements. Twenty subjects with normal occlusion were included as controls. Success rate, maxillary and mandibular transverse dimensions, overjet, overbite and arch length were registered. Results: Stability was equal for the two treatment methods. Small, albeit significant, differences between the groups were assessed with reference to transverse dimensions. No significant difference was seen for overjet and overbite. The treated patients never reached the same transversal width as the normal control group. Conclusions: The long-term stability of posterior crossbite correction with Quad helix and expansion plate was equal. The maxillary width was greater in the control group than the treated groups

Membrane Porters of ATP-Binding Cassette Transport Systems Are Polyphyletic

The ATP-binding cassette (ABC) superfamily consists of both importers and exporters. These transporters have, by tradition, been classified according to the ATP hydrolyzing constituents, which are monophyletic. The evolutionary origins of the transmembrane porter proteins/domains are not known. Using five distinct computer programs, we here provide convincing statistical data suggesting that the transmembrane domains of ABC exporters are polyphyletic, having arisen at least three times independently. ABC1 porters arose by intragenic triplication of a primordial two-transmembrane segment (TMS)-encoding genetic element, yielding six TMS proteins. ABC2 porters arose by intragenic duplication of a dissimilar primordial three-TMS-encoding genetic element, yielding a distinctive protein family, nonhomologous to the ABC1 proteins. ABC3 porters arose by duplication of a primordial four-TMS-encoding genetic element, yielding either eight- or 10-TMS proteins. We assign each of 48 of the 50 currently recognized families of ABC exporters to one of the three evolutionarily distinct ABC types. Currently available high-resolution structural data for ABC porters are fully consistent with our findings. These results provide guides for future structural and mechanistic studies of these important transport systems