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Anomalous proton relaxation, rotational tunnelling and barriers to methyl group rotation in solid acetyl halides.

Rotational excitations of methyl groups attached to carbonyl in solid acetic acid, acetyl fluoride, acetyl chloride and acetyl bromide have been investigated by 1H nuclear magnetic resonance (NMR) relaxation times and field-cycling measurements at two frequencies and various temperatures. The tunnel splittings have been found to occur between 3.3 and 0.08 mu eV making quantum effects important for the relaxation behaviour. For the acetyl halides, similar tunnelling and NMR frequencies lead to an anomalous-looking temperature dependence of the relaxation rates. A consistent description by Haupt's equation is possible. The rotational potentials have been derived from the data and compared with those obtained from microwave spectra of the corresponding isolated molecules. The hindering potential is purely three-fold and the barrier is dominated by the functional group.

Halogens↗

New least squares solutions for estimating the average centre of rotation and the axis of rotation.

A new method is proposed for estimating the parameters of ball joints, also known as spherical or revolute joints and hinge joints with a fixed axis of rotation. The method does not require manual adjustment of any optimisation parameters and produces closed form solutions. It is a least squares solution using the whole 3D motion data set. We do not assume strict rigidity but only that the markers maintain a constant distance from the centre or axis of rotation. This method is compared with other methods that use similar assumptions in the cases of random measurement errors, systematic skin movements and skin movements with random measurement noise. Simulation results indicate that the new method is superior in terms of the algorithm used, the closure of the solution, consistency and minimal manual parameter adjustment. The method can also be adapted to joints with translational movements.

Biomechanical Phenomena↗

The development and evaluation of a disease-specific quality-of-life questionnaire for disorders of the rotator cuff: The Western Ontario Rotator Cuff Index.

OBJECTIVE: The purpose of this study was to develop a valid and reliable disease-specific quality-of-life measurement tool for patients with rotator cuff disease. DESIGN: Health-related quality-of-life measurement tool development. METHODS: Methodology for the development and evaluation of the tool included the following: 1) identification of a specific patient population, 2) generation of potential items, 3) item reduction, 4) pretesting the prototype instrument, 5) determination of reliability, and 6) validation. RESULTS: The final instrument, the Western Ontario Rotator Cuff Index, double dagger has 21 items representing five domains, each with a Visual Analog Scale-type response option. Construct validation demonstrated that this instrument correlated predictably with other measurement tools (Disabilities of the Arm, Shoulder, and Hand outcome measure; American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form; University of California Los Angeles Shoulder Rating Scale; Constant Score; Rowe; Sickness Impact Profile; Short Form 36; and range of motion; 21 of 21 correlations within 0.19). Reliability was very high at 2 weeks, with an intraclass correlation coefficient of 0.96 and was more responsive (sensitive to change) than the other five shoulder measurement tools, global health instruments, and range of motion. CONCLUSIONS: This measurement tool can be used as the primary outcome in clinical trials evaluating treatments in this patient population, although its features are equally attractive for monitoring patients' progress in clinical practice.

Adult↗

Relation of clinical presentation, stenosis morphology, and operator technique to the procedural results of rotational atherectomy and rotational atherectomy-facilitated angioplasty.

BACKGROUND: Rotational atherectomy using the Rotablator has recently become available to treat coronary stenoses. This study was performed to determine the relation of patient characteristics, stenosis morphology, and operator technique to procedural outcome to gain insight into which patients might be best treated with this device. METHODS AND RESULTS: Four hundred stenoses from 316 patients randomly selected from the initial Rotablator experience at three major referral institutions were analyzed. Angiographic data were assessed at a central angiographic laboratory using standardized morphological criteria and caliper measurement. Patients were somewhat more elderly than most percutaneous transluminal coronary angioplasty (PTCA)-treated groups (mean age, 64 +/- 11 years), 74% were men, and the lesions treated were often complex (modified American College of Cardiology/American Heart Association lesion type A, 24%; B1, 40%; B2, 30%; and C, 6%). Elective adjunctive PTCA was used for 82% of stenoses treated. Procedural success was achieved in 89.8% of stenoses (93.5% if results with creatine kinase two to three times normal are not counted as failures), and major ischemic complications (death, 0.3%; non-Q-wave myocardial infarction, 5.7%; Q-wave myocardial infarction, 2.2%; or emergency bypass surgery, 0.9%) occurred in 8.9% of patients. Complications were due to epicardial coronary obstruction in 3.8% of patients and to delayed coronary runoff ("slow reflow") in 5.1% of patients. Procedural failure was correlated independently with outflow obstruction (success rate, 64%; odds ratio for failure, 5.4; multivariate P = .002), lesion irregularity (76%; odds ratio, 3.3; P = .003), stenosis bend > or = 60 degrees (73%; odds ratio, 3.7; P = .03), and female sex (84%; odds ratio, 2.4; P = .03). Ischemic complications were correlated independently with lesion length (> or = 50% narrowing) > or = 4 mm (complication rate, 12%; odds ratio, 3.6; multivariate P = .005), right coronary artery stenosis (13%; odds ratio, 2.4; P = .02), stenosis bend > or = 60 degrees (27%; odds ratio, 6.1; P = .03), and female sex (13%; odds ratio, 3.0; P = .04). Slow reflow was correlated with total burring duration (odds ratio, 1.005/s; multivariate P = .001), right coronary artery stenosis (incidence, 17%; odds ratio, 4.5; P = .009), and to a lesser extent with recent myocardial infarction in the treated territory (44%; odds ratio, 4.3; P = .08). CONCLUSIONS: The procedural outcome of rotational atherectomy is highly correlated with stenosis morphology and location and sex of the patient. After stratification for these parameters, overall outcome with the Rotablator appears to be similar to that with balloon angioplasty and other competing techniques. Short-term outcome with specific subsets of patients may be superior with the Rotablator (calcified stenoses), but this technique might best be avoided in some patients (those with irregular or possibly thrombus-containing stenoses, highly angulated stenoses, and possible right coronary artery stenoses or those associated with impaired distal runoff caused by a recent myocardial infarction or manifest by a fixed thallium defect).

Aged↗

Comparative measurements of anterior tibial translation using the KT-1000 knee arthrometer with the leg in neutral, internal rotation, and external rotation.

Position of the leg while using the KT-1000 knee arthrometer may be an important variable in attaining accurate and reliable measurements. The purpose of this study was to compare the anterior translation of the tibia on the femur with the tibia in neutral, internal rotation (IR), and external rotation (ER). Additionally, data were analyzed to determine the intratester and intertester reliability of the KT-1000 knee arthrometer with the leg in neutral. Data were collected from 50 subjects by two testers and one recorder, according to MEDmetric protocol. Tester 1 performed three pulls or one sequence in neutral, IR, and ER. A second sequence was performed in neutral. Tester 2 performed two sequences in the neutral position. Data in each sequence were averaged and evaluated. Intertester reliability was calculated at r = .64 (poor), while intratester reliability for tester 1 was r = .90 (high) and for tester 2 was r = .86 (good). A repeated measure, one-way ANOVA was used, and results demonstrated a statistical difference of p < .0001, with the difference found between IR when compared with ER and neutral. In conclusion, differences in tibial translation occurred between neutral, IR, and ER of the lower extremity. This may prove valuable for clinicians using the KT-1000.

Adult↗

Anterolateral rotational instability in the ankle joint. An experimental study of anterolateral rotational instability, talar tilt, and anterior drawer sign in relation to injuries to the lateral ligaments.

In seven amputated legs the ankle region was dissected free, and anterolateral rotational instability, talar tilt, and anterior drawer sign in the talocrural joint were studied in relation to varying degrees of injury to the lateral ligaments of the ankle and in relation to various positions of the foot. This revealed a good correlation between the degree of ligamentous injury and the degree of the three different types of instability. Anterolateral rotational instability was maximal when the investigation was performed with the ankle joint in the plantar flexion, whereas the talar tilt was more pronounced with the ankle joint in the neutral position and the anterior drawer sign most distinct when the ankle joint was in dorsal flexion. Compared with the other two signs, the anterior drawer sign proved to be a relatively inconstant type of instability.

Ankle Joint↗

Proximal tibial extension medial rotation osteotomy to correct knee flexion contracture and lateral rotation deformity of tibia after polio.

A proximal tibial extension medial rotation osteotomy was performed on 17 tibias in postpoliomyelitis patients to correct knee flexion contractures simultaneously with the correction of lateral rotation deformity of the tibia through the same osteotomy. Gait improved in 10 patients. Five patients developed recurrence of knee flexion contractures; five more developed greater than 20 degrees genu recurvatum. One patient developed a common peroneal nerve palsy. Because of the high incidence of complications, we recommend that this procedure be abandoned.

Adolescent↗

Proximal rupture and intracoronary entrapment of a rotating device during low-speed rotational coronary angioplasty.

While attempting to recanalize a right coronary artery obstruction by using a low-speed rotating catheter (Rotacs), proximal rupture of the catheter body occurred with entrapment of the blunt tip in the obstruction. To retrieve the device, it was necessary to severe the guiding catheter and the flexible tube of the Rotacs. At low-speed rotation the flexible segment of the catheter was then pulled back.

Angioplasty, Balloon↗

Effective Reduction of Wavenumbers of Rotational and Vibration-Rotational Transitions of LiH X1Sigma+

A deformationally self-consistent procedure is applied to reduce the wavenumbers of 594 pure rotational and vibration-rotational transitions of 7Li1H, 6Li1H, 7Li2H, and 6Li2H to 15 unconstrained and 2 constrained parameters with sigma; = 1.098, sigma = 0.000554 cm-1, and F = 7.704 x 10(14). The quality of the Born-Oppenheimer approximation and the extent of its breakdown in LiH are reexamined. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗

Application of Deformational Self-Consistent Procedure and New Potential Expansion to Effective Reduction of Wavenumbers of Rotational and Vibration-Rotational Transitions of GeS X1Sigma+

A deformationally self-consistent procedure and new expansion of the internuclear potential energy are applied to reduce the wavenumbers of 727 pure rotational and vibration-rotational transitions of nine isotopic variants of GeS to seven radial parameters with varsigma; = 1.048, varsigma = 0.00015 cm-1 and F = 1.32 x 10(15). A potential energy is expanded into a series of the variable xi = (R - R0)/[aR + (1 - a)R0] with a treated as a free-fitted parameter. For GeS, we evaluated a = 1.09255(81). This new expansion includes those of Dunham, Simons-Parr-Finlan, and Ogilvie as special cases corresponding to a = 0, 1, 12. Copyright 1999 Academic Press.

Journal Article↗

An oscillating electric field with thermal noise increases the rotational diffusion and drives rotation in a dipole.

Here we consider a dipole in a viscous medium under the influence of an oscillating electric field and thermal noise. Because of the very low Reynolds numbers involved in molecular processes, we considered overdamped Langevin dynamics. As a consequence the inertia term becomes negligible. We observed a great increase in the rotational diffusion and also net rotation for some values of the parameters.

Journal Article↗

Optimizing precision of rotating-analyzer and rotating-compensator ellipsometers.

I investigate the dependence of shot-noise-limited uncertainties of the ellipsometric parameters psi, and delta for the rotating-analyzer ellipsometer (RAE) and the rotating-compensator ellipsometer (RCE) of the polarizer-sample-compensator-analyzer type. The development is general and takes into account correlations among the Fourier coefficients of the transmitted intensity, in particular the average intensity, which is necessarily correlated with all other coefficients through normalization. The results are expressed in terms of the traditional uncertainties delta(psi) and delta(delta) of the ellipsometric parameters psi and delta, respectively, although a more appropriate measure of uncertainty is the differential area 2delta(psi) x sin psi(delta)delta on the unit-radius Poincaré sphere. Numerical results for broadband operation from 1.5 to 6.0 eV with a Si sample show that the optimum measurement conditions for both configurations occur when the intensity of light reflected from the sample is approximately balanced between the TE and the TM modes, and, for the RCE, when the analyzer azimuth is essentially equal to that of the polarizer. Under typical broadband operating conditions in which components cannot be optimized on a wavelength-by-wavelength basis, the RCE is better at determining delta, whereas the RAE is better at determining psi. The approach is easily generalized to other configurations and other types of experimental uncertainty, both random and systematic.

Journal Article↗

Rotational relaxation of neutral red in alkanes: effect of solvent size on probe rotation.

Rotational reorientation times of a polar molecule neutral red (NR) have been measured in n-alkanes using steady-state fluorescence depolarization technique. The rotational dynamics of NR in alkanes is described by the Stokes-Einstein-Debye hydrodynamic theory with slip boundary condition. However, we have observed that as the size of the solvent molecule becomes bigger than the size of the solute molecule, the probe molecule experiences reduced friction and the experimentally measured reorientation times are shorter than those predicted by the hydrodynamic theory. These size effects have been analyzed using quasihydrodynamic theories.

Alkanes↗

A new mode of rotating gel electrophoresis for fractionating linear and circular duplex DNA: the effects of electrophoresis during the gel's rotation.

Linear and circular DNA have been fractionated by use of rotating gel electrophoresis (RGE; RGE is a form of pulsed-field gel [PFG] electrophoresis) in a mode not previously described. This new mode consists of electrophoresis while repeating the following two-step process: rotating the gel by 2 pi radians, followed by holding the gel motionless. With this new mode of RGE: (1) The fractionation by length of linear DNA is greater than that achieved without changing the direction of the field. (2) The simultaneous separation of open circular DNA (48.5-97 Kb) from linear DNA (1-180 Kb) and fractionation by length of open circular DNA is achieved. These latter separations have not previously been achieved by a one-dimensional electrophoresis. The mechanism of linear DNA's sieving in the new mode appears different from that of all previously described procedures of PGF electrophoresis.

Bacteriophage lambda↗

Rotation of cytochrome P-450. Complex formation of cytochrome P-450 with NADPH-cytochrome P-450 reductase in liposomes demonstrated by combining protein rotation with antibody-induced cross-linking.

Purified rat liver microsomal cytochrome P-450 and NADPH-cytochrome P-450 reductase were co-reconstituted in phosphatidylcholine-phosphatidylethanolamine-phosphatidylserine vesicles by a cholate dialysis technique. Rotational diffusion of cytochrome P-450 was measured by detecting the decay of absorption anisotropy r(t), after photolysis of the heme X CO complex by a vertically polarized laser flash. All cytochrome P-450 was found to be rotationally mobile when co-reconstituted with equimolar amounts of NADPH-cytochrome P-450 reductase in lipid to cytochrome P-450 ((L/P450)) = 1 (w/w] vesicles. Antibodies against NADPH-cytochrome P-450 reductase were raised. Their specificity was demonstrated by Ouchterlony double diffusion analysis. Antireductase Fab fragments were prepared from antireductase IgG by papain digestion. The N-demethylation of benzphetamine, catalyzed by the proteoliposomes, was significantly inhibited by antireductase IgG and by antireductase Fab fragments. Cross-linking of NADPH-cytochrome P-450 reductase by antireductase IgG resulted in complete immobilization of cytochrome P-450 in L/P450 = 1 vesicles. Antireductase IgG also immobilized cytochrome P-450 in L/P450 = 5 vesicles, although the degree of immobilization was slightly smaller. No immobilization of cytochrome P-450 in L/P450 = 1 vesicles was detected in the presence of antireductase Fab fragments or preimmune IgG. These results further support the proposal of the formation of monomolecular complexes between cytochrome P-450 and NADPH-cytochrome P-450 reductase in liposomal membranes (Gut, J., Richter, C., Cherry, R.J., Winterhalter, K.H., and Kawato, S. (1982) J. Biol. Chem. 257, 7030-7036).

Animals↗

The repair of chronic massive ruptures of the rotator cuff of the shoulder by use of a freeze-dried rotator cuff.

In sixteen patients with massive tears of the rotator cuff of the shoulder, bridging of the defect with a freeze-dried graft of a rotator cuff from a cadaver produced a satisfactory repair in all cases. A good or excellent functional result was obtained in all but two patients, with a definite decrease or absence of nocturnal pain in all sixteen. The operative technique includes avoidance of a complete acromionectomy and an adequate suture of the deltoid muscle to the acromion after an acromioplasty.

Acromioclavicular Joint↗

Organization of postural responses following a rotational support surface perturbation, after TKA: sagittal plane rotations.

Proprioceptive dysfunction, related to osteoarthritis and total knee arthroplasty (TKA) may be related to changes in gait, and may result in balance impairment. This study examined the organization of postural responses to rotational support surface perturbations after TKA. Eight TKA patients and nine control participants volunteered. EMG was collected bilaterally from lower limb muscles. Kinematic data were collected using an OPTOTRAK system. The temporal pattern of muscle activation was preserved in both the surgical and sound limbs of the patient groups, while muscle activation amplitude was reduced. Knee joint angular displacement was reduced in both limbs among patients. COM displacement was not different. Patients demonstrated a different method in recovering posture control following a postural perturbation. Bilateral changes appear to reflect a simplification in the organization of the motor response, in response to the needs of the injured, or previously injured limb.

Aged↗

Anatomic rotational relationships of the proximal tibia, distal femur, and patella: implications for rotational alignment in total knee arthroplasty.

The orientation of the femur, tibia, and patella are important considerations in total knee arthroplasty. Our goal was to describe the relationships between the femoral epicondylar (FE) axis, posterior femoral (PF) axis, posterior tibial (PT) axis, patellar (PAT) axis, and patellar ligament (PL). A secondary goal was to determine where the short axis of the tibial tray intersects the patellar ligament as a function of tibial component rotation. Thirty normal magnetic resonance imaging (MRI) scans were analyzed. Strong relationships were found between the FE and PAT axes (2 degrees +/- 3 degrees, r(2) = 0.73), and between the FE and PF axes (6 degrees +/- 2 degrees, r(2) = 0.77). When the tibial baseplate was aligned along the PT axis, 30% of the cases were in an ideal position. When the FE axis was used, 73% were ideal.

Adult↗