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At least 199 records · Page 11Linked to original sources
PubMed1995

An investigation into the relative efficiency of dextro-rotating and laevo-rotating spiral paste fillers in the southern hemisphere.

Much published work evidences the differences of object-rotation which occur between the northern and the southern hemispheres; particularly commonly the evacuation of water or other liquids through a hole. This paper reports the results of an investigation into the efficiency with which a conventionally-wound clockwise-spiral root canal paste filler obturated experimentally instrumented root canals in the southern hemisphere as compared with those using a filler wound with an anticlockwise spiral.

Australia↗
PubMed1989

[Rotational angioplasty--recanalization of chronic arterial occlusion using a slowly rotating catheter. Clinical results with 100 patients].

Between December 1986 and January 1989, 100 patients with chronic occlusions of peripheral arteries were treated with the new technique of low speed rotational angioplasty. This uses a relatively thick, flexible and blunt catheter, which is driven by an electric motor (100 to 200 r.p.m.). The success rate in the superficial femoral and popliteal arteries of the initial intervention for occlusions less than 10 cm was 90%, for occlusions of less than 10 cm, it was 80%. Occlusions on which conventional techniques had failed were successfully recanalized in 65%. Recanalisation was also successful in seven out of 12 patients with occluded iliac arteries. There were no perforations or other serious complications. It is concluded that the new method is particularly effective and safe for recanalisation of chronic vascular occlusions and should also be considered for cases which previously could only be treated surgically.

Adult↗
PubMed2001

[The fibrous frame of the rotator cuff. Contributions of an in vivo three dimensional study of the tendons of the rotator cuff].

The presence of a fibrous frame within the rotator cuff has been recently emphasized. This frame may be of interest in understanding of shoulder physiology and in attempts to improve shoulders disorders treatments. We report an original method to study the fibrous frame. MRI were done in healthy volunteers. 3D reconstruction were obtained and provided a 3D image of the fibrous frame. This technic should allow to calculate, for instance, the angles between the cuff muscles and the upper end of the humerus.

Humans↗
PubMed1993

[Results of endoscopic treatment of non-broken tendinopathies of the rotator cuff. 2. Calcifications of the rotator cuff].

The authors studied the results of the arthroscopic treatment of the chronic calcifying tendinitis within a multi-center study of the French Society of Arthroscopy. 112 patients were available for the study. All shoulders had a preoperative radiographic clinical and radiographic evaluation. At follow up, functional results were assessed, using the Constant score, and X rays allowed to appreciate the acromial shape and the calcific deposit aspect. Several arthroscopic procedures were used on the calcification (respect or removal), and the coracoacromial arch (respect, ACL release or acromioplasty). This study found an objective success rate of 89 per cent and a patient subjective satisfaction rate of 82 per cent. Based on follow up radiographs, 88 per cent of the patients had a complete disappearance of the calcific deposit. There were no recurrence, no secondary rotator cuff tear. The results were not correlated with the age of the patients, or with the radiographic aspect (type, size, localization) of the calcification. The results were correlated with the arthroscopic procedure: they were better when the calcification had been removed (superior to deposit respect). Associated acromioplasty gave no better results: it was only considered as necessary when the calcification was not found (12 per cent). The greatest care must be taken in the surgical indication for this pathology because of a high rate of spontaneous resorption. The authors conclude that the arthroscopic surgery is a very effective method for chronic calcific tendinitis, compared to open procedure.

Adult↗
PubMed2003

Progressive collapse of transposed necrotic area after transtrochanteric rotational osteotomy for osteonecrosis of the femoral head induces osteoarthritic change. Mid-term results of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head.

INTRODUCTION: Osteonecrosis of the femoral head is usually progressive, and once collapse of the femoral head develops, joint destruction almost invariably follows. Therefore, for partial osteonecrosis of the femoral head, various types of osteotomies have been developed in an attempt to save the femoral head and maintain the natural function of the hip joint. MATERIALS AND METHODS: We reviewed 25 hips in 21 patients for a mean follow-up period of 6.4 years after Sugioka's transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head. RESULTS: The clinical results were excellent or good in 20 hips (80%), and radiological success was observed in 15 hips (60%) with an absence of both collapse of the newly established weight-bearing area of the femoral head and narrowing of the joint space. Progressive collapse of the transposed necrotic area was noted in 10 hips (40%), and of these 10 hips, narrowing of the joint space was observed in 7 (70%) at follow-up. A significant correlation was demonstrated between progressive collapse of the transposed necrotic area and narrowing of the joint space. Growth of an osteophyte of the femoral head was observed postoperatively in 16 hips (64%), particularly at anterior and lateral sites of the femoral head. CONCLUSIONS: Though collapse of a new weight-bearing area can be prevented, progressive collapse of the transposed necrotic area induces anterior joint instability, giving rise to osteoarthritic change. It is therefore concluded that prevention of the collapse of the transposed necrotic area is important for satisfactory long-term results.

Adult↗
PubMed2003

Rotational isomerism involving an acetylenic carbon IV: synthesis and structure of bis(1,1';3',1"-terphenyl-2'-yl)ethynes: molecular design of sterically congested alkynes toward restricted rotation about acetylenic axis.

The title diphenylethyne derivative with 4-methylphenyl (tolyl) groups at all the ortho positions was synthesized by the Stille or Sonogashira coupling from the corresponding iodide. The X-ray structure revealed that the two terminal phenyl groups at the sp carbons are twisted by 63 degrees out of the coplanar conformation to avoid steric interactions between the tolyl groups. The relative stabilities of possible conformers were analyzed by the PM3 calculations. The axially chiral derivative with two methoxymethyl groups showed no evidence of restricted rotation about the acetylenic axis by VT NMR measurements, its barrier being less than 35 kJ mol(-1). The spectroscopic features and reactivities of this sterically congested alkyne are also described.

Acetylene↗
PubMed2006

Gyroscope-like molecules consisting of three-spoke stators that enclose "switchable" neutral dipolar rhodium rotators; reversible cycling between faster and slower rotating Rh(CO)I and Rh(CO)2I species.

trans-Rh(CO)(Cl)(P((CH(2))(14))(3)P) is prepared from trans-Rh(CO)(Cl)(P((CH(2))(6)CH[double bond, length as m-dash]CH(2))(3))(2) by a metathesis/hydrogenation sequence, and converted by substitution or addition reactions to Rh(CO)(I), Rh(CO)(2)(I), Rh(CO)(NCS), and Rh(CO)(Cl)(Br)(CCl(3)) species; the Rh(CO)(Cl) and Rh(CO)(I) moieties rapidly rotate within the cage-like diphosphine, but the other rhodium moieties do not.

Journal Article↗
PubMed2001

Rotations and rotation matrices.

In molecular replacement, a model, described as a list of orthogonal coordinates, is to be moved into a new position and orientation. The orthogonal coordinate system also has to be related to the crystallographic system, which may not be orthogonal, and crystallographic symmetry must be considered, which applies to coordinates expressed as fractions of the unit cell. Elementary properties of rotation matrices and their representation as polar or Eulerian angles are discussed.

Crystallography↗
PubMedDate not supplied

Imaging with rotating slit apertures and rotating collimators.

The statistical quality of conventional nuclear medical imagery is limited by the small signal collected through low-efficiency conventional apertures. Coded-aperture imaging overcomes this by employing a two-step process in which the object is first efficiently detected as an "encoded" form which does not resemble the object, and then filtered (or "decoded") to form an image. We present here the imaging properties of a class of time-modulated coded apertures which, unlike most coded apertures, encode projections of the object rather than the object itself. These coded apertures can reconstruct a volume object nontomographically, tomographically (one plane focused), or three-dimensionally. We describe a new decoding algorithm that reconstructs the object from its planar projections. Results of noise calculations are given, and the noise performance of these coded-aperture systems is compared to that of conventional counterparts. A hybrid slit-pinhole system which combines the imaging advantages of a rotating slit and a pinhole is described. A new scintillation detector which accurately measures the position of an event in one dimension only is presented, and its use in our coded-aperture system is outlined. Finally, results of imaging test objects and animals are given.

Animals↗
PubMed1986

Rotator cuff tears: preliminary application of high-resolution MR imaging with counter rotating current loop-gap resonators.

A new class of radio frequency (RF) coils for magnetic resonance (MR) imaging and spectroscopy is introduced. The coils consist of two loop-gap resonators of equal diameters positioned along a common axis. They are tuned to the mode in which the current in the two loops flows in opposite directions. These coils are "decoupled" from a uniform excitation field of arbitrary orientation (including circularly polarized fields) by intrinsic decoupling and by means of back-to-back fast recovery diodes. Measurements made with the coils and a phantom saline tank indicate that the signal-to-noise ratio obtainable with these coils is almost identical to that obtained with single loops. Imaging of several anatomic areas, including knee, wrist, and shoulder, has been performed with a 1.5-T MR system that uses circularly polarized RF. A small series of patients with torn rotator cuffs underwent imaging. Difficulties in establishing the diagnosis with MR imaging because of anatomic complexity are illustrated. The value of pulse sequences with long repetition times to increase the signal intensity of fluid in the joint is shown.

Humans↗
PubMed2002

Rotational atherectomy does not reduce recurrent in-stent restenosis: results of the angioplasty versus rotational atherectomy for treatment of diffuse in-stent restenosis trial (ARTIST).

BACKGROUND: Aim of this trial was to compare rotational atherectomy followed by balloon angioplasty (rotablation [ROTA] group) with balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA] group) alone in patients with diffuse in-stent restenosis. METHODS AND RESULTS: The ARTIST study is a multicenter, randomized, prospective European trial with 298 patients with in-stent restenosis>70% (mean lesion length, 14 +/- 8 mm) in stents, implanted in coronary arteries for >/= 3 months. In the PTCA group, angioplasty was performed at the discretion of the local investigator, and rotablation was performed by using a stepped-burr approach followed by adjunctive PTCA with low (</= 6 atm) inflation pressure. Intravascular ultrasound during the intervention and at follow-up was used in a substudy in 86 patients (45 PTCA, 41 ROTA). Angiography demonstrated no difference regarding the short-term outcome, with equivalent procedural success rates defined as remaining stenosis <30% (89% PTCA, 88% ROTA). However, the results showed that, in the long term, PTCA was a significantly better strategy than ROTA. Mean net gain in minimal lumen diameter was 0.67 mm and 0.45 mm for PTCA and ROTA, respectively (P=0.0019). Mean gain in diameter stenosis was 25% and 17% (P=0.002), resulting in restenosis (>/= 50%) rates of 51% (PTCA) and 65% (ROTA) (P=0.039). By intravascular ultrasound, the major difference was the missing stent over-expansion during PTCA after ROTA. Six-month event-free survival was significantly higher after PTCA (91.3%) compared with ROTA (79.6%, P=0.0052). CONCLUSIONS: In terms of the primary objective of the study, PTCA produced a significantly better long-term outcome than ROTA followed by adjunctive low-pressure PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1984

Rapid precision interferometry for the analytical ultracentrifuge. III. Determination of period of rotation, frequency of rotation, and elapsed time.

The approaches presented in this series of papers make possible rapid gathering, reduction, and analysis of data from the Rayleigh interference optical system of an analytical ultracentrifuge. Instrumentation described in this paper provides some of the timing and measurement circuits necessary for a microprocessor or minicomputer to determine the rotor frequency, rotor period, and elapsed time of an experiment. It includes simple but effective circuits to generate precise rotor timing pulses that are useful for synchronization of pulsed light sources. Circuits to control photographic operations in the ultracentrifuge are described briefly. All of these circuits are interfaced to a simple microcomputer address/data bus. An adapter between this bus and a Q-bus (for a DEC LSI-11/2 or LSI 11/23 microcomputer) is also described. The circuits presented have been used in this laboratory over a 3-year period. They have proven reliable and form an integral part of the real-time data acquisition systems that have been constructed.

Interferometry↗