Search results for "rotation"
showing 10 items of 935 documents
A Novel Digital Technique for Measuring the Accuracy of an Indirect Bonding Technique Using Fixed Buccal Multibracket Appliances
2021
The aim of this study was to analyze the accuracy and predictability of the indirect bonding technique of fixed buccal multibracket appliances using a customized iterative closest point algorithm. Materials and Methods: A total of 340 fixed buccal multibracket appliances were virtually planned and bonded on 34 experimental anatomically based acrylic resin models by using orthodontic templates designed and manufactured to indirectly bond the fixed buccal multibracket appliances. Afterwards, the models were submitted to a three-dimensional impression technique by an intraoral scanner, and the standard tessellation language digital files from the virtual planning and the digital impression wer…
Immediate three-dimensional changes in the oropharynx after different mandibular advancements in counterclockwise rotation orthognathic planning
2021
Background A retrospective cohort study was performed to evaluate the immediate effect on the oropharynx dimensions from different mandibular advancements in patients undergone counterclockwise rotation (CCW) of the maxillomandibular complex. Material and Methods 138 CBCT images of patients, who had undergone orthognathic surgery, were identified from Dolphin Imaging archive according to pre- (T0) and post-operative (T1) times. Each pre-operative CBCT image was selected considering retrognathic mandible. Superimpositions of CBCT images were performed to measure mandibular advancement at B point in millimeters (mm) and divided into three groups: G1 ( 10 mm). For evaluating oropharynx dimensi…
Influence of the Geometrical Cross-Section Design on the Dynamic Cyclic Fatigue Resistance of NiTi Endodontic Rotary Files—An In Vitro Study
2021
The aim of this study was to analyze and compare the influence of the geometrical cross-section design on the dynamic cyclic fatigue resistance of NiTi endodontic rotary files. Materials and Methods: Forty sterile endodontic rotary files were selected and distributed into the following study groups: A: 25.06 double S-shaped cross-section NiTi alloy endodontic rotary files (Mtwo) (n = 10)
Understanding Paleomagnetic Rotations in Sicily: Thrust Versus Strike-Slip Tectonics
2018
The paleomagnetic investigation of the western Sicily Maghrebian belt has revealed since the 1970s that large clockwise rotations up to 140° with respect to the Hyblean-African foreland occurred synchronous with Tertiary shortening of the chain. The observation that rotations decrease stepwise from internal to external tectono-stratigraphic units led in the 1990s to a widely accepted model postulating that rotational thrust-sheet emplaced during forward orogenic propagation. More recently, other authors suggested that clockwise rotations from Sicily are conversely the result of late orogenic dextral strike-slip tectonics. Here we report on a paleomagnetic investigation of 30 Jurassic-Eocene…
Greenberg dysplasia: first reported case with additional non-skeletal malformations and without consanguinity
2001
In 1988 Greenberg et al. reported an association of fetal hydrops with irregular calcification and moth-eaten skeletal dysplasia. Here, we report on the first case of this disorder accompanied by additional malformations (omphalocele, intestinal malrotation, disturbed fingernails and toes, hypolobated lungs) in a German couple without consanguinity (karyotype 46,XY). Sonograpically, the fetus was characterised by tetraphokomelia, severe generalised hydrops, pulmonal hypoplasia and hepato-splenomegaly. Greenberg dysplasia should be considered in differential diagnosis in cases with severe fetal hydrops and phokomelia on antenatal sonography.
Hochfrequenz-Rotationsatherektomie bei koronarer Herzkrankheit
2008
Percutaneous high frequency coronary rotational ablation (PTCR) was used in 10 patients with significant coronary artery disease. PTCR removes arteriosclerotic material from the vessel wall. A diamond-coated (60-80 micron) brass burr-drill, fastened to a flexible drive shaft rotating and tracking along a central coaxial guide wire, was used. The turbine rotates the drive shaft in excess of 150,000-190,000 revolutions per minute. PTCR was successful in all patients, but in three additional percutaneous transluminal coronary angioplasty (PTCA) was then successfully performed. Coronary dissection occurred only once, requiring surgery which was successful. No vessel perforation was observed. Al…
Radio and Microwave Spectroscopy of 0.2PMN-0.4PSN-0.4PZN Relaxor Ceramics
2005
Dielectric spectroscopy results of 0.2PbMg 1/3 Nb 2/3 O 3 -0.4PbSc 1/2 Nb 1/2 O 3 -0.4PbZn 1/3 Nb 2/3 O 3 ceramics are reported for 200 < T < 450 K and 20 Hz < v < 11 GHz. Dielectric constant is very high (more than 12000) in the vicinity of the peak. Anomalous broad dielectric relaxation has been observed near and below the temperature of the maximum permittivity, T m (at 1 kHz). The distribution of relaxation times have been calculated directly from the dielectric spectra. At higher temperatures than the maximum permittivity, T m the distribution of the relaxation times is symmetrically shaped (Cole-Cole function satisfactory describes the dielectric response). At lower temperatures, the …
Über den adäquaten Reiz des Bogengangsystems
1953
An analysis is given of the processes in the semicircular canals during adequate stimulation, emphasizing especially the forces acting on the cupula itself. In this way it is possible to understand the physical and physiological phenomena in straight-lined and rotation movements.
Quantum effects and orientational ordering in adsorbed layers of linear molecules
1994
We study the influence of quantum fluctuations on the herringbone transition in adsorbed complete √3-mono-layers of diatomic molecules. Using Path-Integral Monte Carlo simulations for rotations, we can quantify the shift of the transition temperature for a highly realistic model to describe N2 on graphite. In addition, the zero-point motion of the librating molecules depresses the ground-state order parameter. We compare the benchmark data to quadratic Feynman-Hibbs effective potential simulations and to a quasiharmonic approximation. Using a simplified model for this transition, we study systematically quantum effects being relevant for lighter molecules. Depending on the rotator's rotatio…
Alkaline cavities and tetrahedra in and solid solutions
1997
Seven different crystals were grown with 0 < x < 2 while seven different crystals were grown with , the limit value x = 1 corresponding to the clearly defined compound. A crystallographic study of these solid solutions was performed by comparison with the pure crystal. Structures were solved in the Pnma space group for the rubidium solid solutions and in the space group for the potassium ones. It was shown that the distribution of Cs and Rb, or Cs and K, among the two cationic sites called and was not random: Rb and K exhibit a higher affinity for the smallest cavity, the site. While the phase transition of and can be interpreted as rotations of the rigid tetrahedra mainly around the a dire…