Malposition of the tibial tubercle during flexion in knees with patellofemoral arthritis

International Nuclear Information System (INIS)

Nagamine, R.; Miura, H.; Tanaka, K.; Urabe, K.; Iwamoto, Y.; Inoue, Y.; Okamoto, Y.; Nishizawa, M.

1997-01-01

Objective. To assess the mechanisms contributing to the induction of patellofemoral arthritis (PF-OA). Design and patients. A computed tomography scan was taken at three levels of the lower extremity in full extension and at 30 of flexion. The cuts were superimposed and 12 parameters were compared in 17 PF-OA knees and 27 normal knees to assess the rotation angle of the tibial tubercle. Results. Although the tibial tubercle was in almost the same position in full extensioin in the normal and PF-OA knees, it was positioned significantly laterally at 30 of flexion in PF-OA knees. Also the articular surface of the lateral femoral condyle was significantly narrower or steeper in PF-OA knees. Conclusion. Anatomic variations and mechanical abnormalities were identified in the PF-OA knees. (orig.)

Clinical outcome of increased flexion gap after total knee arthroplasty. Can controlled gap imbalance improve knee flexion?

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Ismailidis, P; Kuster, M S; Jost, B; Giesinger, K; Behrend, H

2017-06-01

Increased range of motion (ROM) while maintaining joint stability is the goal of modern total knee arthroplasty (TKA). A biomechanical study has shown that small increases in flexion gap result in decreased tibiofemoral force beyond 90° flexion. The purpose of this paper was to investigate clinical implications of controlled increased flexion gap. Four hundred and four TKAs were allocated into one of two groups and analysed retrospectively. In the first group (n = 352), flexion gap exceeded extension gap by 2.5 mm, while in the second group (n = 52) flexion gap was equal to the extension gap. The procedures were performed from 2008 to 2012. The patients were reviewed 12 months postoperatively. Objective clinical results were assessed for ROM, mediolateral and sagittal stability. Patient-reported outcome measures were the WOMAC score and the Forgotten Joint Score (FJS-12). After categorizing postoperative flexion into three groups (poor < 90°, satisfactory 91°-119°, good ≥ 120°) significantly more patients in group 1 achieved satisfactory or good ROM (p = 0.006). Group 1 also showed a significantly higher mean FJS-12 (group 1: 73, group 2: 61, p = 0.02). The mean WOMAC score was 11 in the first and 14 in the second group (n.s.). Increase in flexion gap did not influence knee stability. The clinical relevance of this study is that a controlled flexion gap increase of 2.5 mm may have a positive effect on postoperative flexion and patient satisfaction after TKA. Neither knee stability in the coronal and sagittal planes nor complications were influenced by a controlled increase in flexion gap. III.

Gender differences in rotation of the shank during single-legged drop landing and its relation to rotational muscle strength of the knee.

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Kiriyama, Shinya; Sato, Haruhiko; Takahira, Naonobu

2009-01-01

Increased shank rotation during landing has been considered to be one of the factors for noncontact anterior cruciate ligament injuries in female athletes. There have been no known gender differences in rotational knee muscle strength, which is expected to inhibit exaggerated shank rotation. Women have less knee external rotator strength than do men. Lower external rotator strength is associated with increased internal shank rotation at the time of landing. Controlled laboratory study. One hundred sixty-nine healthy young subjects (81 female and 88 male; age, 17.0 +/- 1.0 years) volunteered to participate in this study. The subjects performed single-legged drop landings from a 20-cm height. Femoral and shank kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the joint angles around the knee (flexion/extension, valgus/varus, and internal/external rotation) were calculated. The maximal isometric rotational muscle strength of the knee was measured at 30 degrees of knee flexion in a supine position using a dynamometer. The female subjects had significantly less external shank rotation strength than did the male subjects (P external rotation strength and the peak shank internal rotation angle during landing (r = -0.322, P external rotator strength. This may lead to large shank internal rotation movement during the single-legged drop landing. Improving strength training of the external rotator muscle may help decrease the rates of anterior cruciate ligament injury in female athletes.

Flexion in Abell 2744

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Bird, J. P.; Goldberg, D. M.

2018-05-01

We present the first flexion-focused gravitational lensing analysis of the Hubble Frontier Field observations of Abell 2744 (z = 0.308). We apply a modified Analytic Image Model technique to measure source galaxy flexion and shear values at a final number density of 82 arcmin-2. By using flexion data alone, we are able to identify the primary mass structure aligned along the heart of the cluster in addition to two major substructure peaks, including an NE component that corresponds to previous lensing work and a new peak detection offset 1.43 arcmin from the cluster core towards the east. We generate two types of non-parametric reconstructions: flexion aperture mass maps, which identify central core, E, and NE substructure peaks with mass signal-to-noise contours peaking at 3.5σ, 2.7σ, and 2.3σ, respectively; and convergence maps derived directly from the smoothed flexion field. For the primary peak, we find a mass of (1.62 ± 0.12) × 1014 h-1 M⊙ within a 33 arcsec (105 h-1 kpc) aperture, a mass of (2.92 ± 0.26) × 1013 h-1 M⊙ within a 16 arcsec (50 h-1 kpc) aperture for the north-eastern substructure, and (8.81 ± 0.52) × 1013 h-1 M⊙ within a 25 arcsec (80 h-1 kpc) aperture for the novel eastern substructure.

Malposition of the tibial tubercle during flexion in knees with patellofemoral arthritis

Energy Technology Data Exchange (ETDEWEB)

Nagamine, R.; Miura, H.; Tanaka, K.; Urabe, K.; Iwamoto, Y. [Department of Orthopaedic Surgery, Kyushu Univ. (Japan); Inoue, Y.; Okamoto, Y.; Nishizawa, M. [Department of Orthopaedic Surgery, JR Kyushu Hospital, Kitakyushu City (Japan)

1997-10-01

Objective. To assess the mechanisms contributing to the induction of patellofemoral arthritis (PF-OA). Design and patients. A computed tomography scan was taken at three levels of the lower extremity in full extension and at 30 of flexion. The cuts were superimposed and 12 parameters were compared in 17 PF-OA knees and 27 normal knees to assess the rotation angle of the tibial tubercle. Results. Although the tibial tubercle was in almost the same position in full extensioin in the normal and PF-OA knees, it was positioned significantly laterally at 30 of flexion in PF-OA knees. Also the articular surface of the lateral femoral condyle was significantly narrower or steeper in PF-OA knees. Conclusion. Anatomic variations and mechanical abnormalities were identified in the PF-OA knees. (orig.) With 8 figs., 1 tab., 11 refs.

Head flexion angle while using a smartphone.

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Lee, Sojeong; Kang, Hwayeong; Shin, Gwanseob

2015-01-01

Repetitive or prolonged head flexion posture while using a smartphone is known as one of risk factors for pain symptoms in the neck. To quantitatively assess the amount and range of head flexion of smartphone users, head forward flexion angle was measured from 18 participants when they were conducing three common smartphone tasks (text messaging, web browsing, video watching) while sitting and standing in a laboratory setting. It was found that participants maintained head flexion of 33-45° (50th percentile angle) from vertical when using the smartphone. The head flexion angle was significantly larger (p smartphone, could be a main contributing factor to the occurrence of neck pain of heavy smartphone users. Practitioner Summary: In this laboratory study, the severity of head flexion of smartphone users was quantitatively evaluated when conducting text messaging, web browsing and video watching while sitting and standing. Study results indicate that text messaging while sitting caused the largest head flexion than that of other task conditions.

Does rehabilitation of cervical lordosis influence sagittal cervical spine flexion extension kinematics in cervical spondylotic radiculopathy subjects?

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Moustafa, Ibrahim Moustafa; Diab, Aliaa Attiah Mohamed; Hegazy, Fatma A; Harrison, Deed E

2017-01-01

To test the hypothesis that improvement of cervical lordosis in cervical spondylotic radiculopathy (CSR) will improve cervical spine flexion and extension end range of motion kinematics in a population suffering from CSR. Thirty chronic lower CSR patients with cervical lordosis lordosis (p lordosis in the study group was associated with significant improvement in the translational and rotational motions of the lower cervical spine. This finding provides objective evidence that cervical flexion/extension is partially dependent on the posture and sagittal curve orientation. These findings are in agreement with several other reports in the literature; whereas ours is the first post treatment analysis identifying this relationship.

Knee joint moments during high flexion movements: Timing of peak moments and the effect of safety footwear.

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Chong, Helen C; Tennant, Liana M; Kingston, David C; Acker, Stacey M

2017-03-01

(1) Characterize knee joint moments and peak knee flexion moment timing during kneeling transitions, with the intent of identifying high-risk postures. (2) Determine whether safety footwear worn by kneeling workers (construction workers, tile setters, masons, roofers) alters high flexion kneeling mechanics. Fifteen males performed high flexion kneeling transitions. Kinetics and kinematics were analyzed for differences in ascent and descent in the lead and trail legs. Mean±standard deviation peak external knee adduction and flexion moments during transitions ranged from 1.01±0.31 to 2.04±0.66% body weight times height (BW∗Ht) and from 3.33 to 12.6% BW∗Ht respectively. The lead leg experienced significantly higher adduction moments compared to the trail leg during descent, when work boots were worn (interaction, p=0.005). There was a main effect of leg (higher lead vs. trail) on the internal rotation moment in both descent (p=0.0119) and ascent (p=0.0129) phases. Peak external knee adduction moments during transitions did not exceed those exhibited during level walking, thus increased knee adduction moment magnitude is likely not a main factor in the development of knee OA in occupational kneelers. Additionally, work boots only significantly increased the adduction moment in the lead leg during descent. In cases where one knee is painful, diseased, or injured, the unaffected knee should be used as the lead leg during asymmetric bilateral kneeling. Peak flexion moments occurred at flexion angles above the maximum flexion angle exhibited during walking (approximately 60°), supporting the theory that the loading of atypical surfaces may aid disease development or progression. Copyright © 2016 Elsevier B.V. All rights reserved.

The Cervical Vestibular-Evoked Myogenic Potentials (cVEMPs) Recorded Along the Sternocleidomastoid Muscles During Head Rotation and Flexion in Normal Human Subjects.

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Ashford, Alexander; Huang, Jun; Zhang, Chunming; Wei, Wei; Mustain, William; Eby, Thomas; Zhu, Hong; Zhou, Wu

2016-08-01

Tone burst-evoked myogenic potentials recorded from tonically contracted sternocleidomastoid muscles (SCM) (cervical VEMP or cVEMP) are widely used to assess the vestibular function. Since the cVEMP response is mediated by the vestibulo-collic reflex (VCR) pathways, it is important to understand how the cVEMPs are determined by factors related to either the sensory components (vestibular end organs) or the motor components (SCM) of the VCR pathways. Compared to the numerous studies that have investigated effects of sound parameters on the cVEMPs, there are few studies that have examined effects of SCM-related factors on the cVEMPs. The goal of the present study is to fill this knowledge gap by testing three SCM-related hypotheses. The first hypothesis is that contrary to the current view, the cVEMP response is only present in the SCM ipsilateral to the stimulated ear. The second hypothesis is that the cVEMP response is not only dependent on tonic level of the SCM, but also on how the tonic level is achieved, i.e., by head rotation or head flexion. The third hypothesis is that the SCM is compartmented and the polarity of the cVEMP response is dependent on the recording site. Seven surface electrodes were positioned along the left SCMs in 12 healthy adult subjects, and tone bursts were delivered to the ipsilateral or contralateral ear (8 ms plateau, 1 ms rise/fall, 130 dB SPL, 50-4000 Hz) while subjects activated their SCMs by head rotation (HR condition) or chin downward head flexion (CD condition). The first hypothesis was confirmed by the finding that the contralateral cVEMPs were minimal at all recording sites for all the tested tones during both HR and CD conditions. The second hypothesis was confirmed by the finding that the ipsilateral cVEMPs were larger in HR condition than in CD condition at recording sites above and below the SCM midpoint. Finally, the third hypothesis was confirmed by the finding that the cVEMPs exhibit reversed polarities at the sites

Needle puncture in rabbit functional spinal units alters rotational biomechanics.

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Hartman, Robert A; Bell, Kevin M; Quan, Bichun; Nuzhao, Yao; Sowa, Gwendolyn A; Kang, James D

2015-04-01

An in vitro biomechanical study for rabbit lumbar functional spinal units (FSUs) using a robot-based spine testing system. To elucidate the effect of annular puncture with a 16 G needle on mechanical properties in flexion/extension, axial rotation, and lateral bending. Needle puncture of the intervertebral disk has been shown to alter mechanical properties of the disk in compression, torsion, and bending. The effect of needle puncture in FSUs, where intact spinal ligaments and facet joints may mitigate or amplify these changes in the disk, on spinal motion segment stability subject to physiological rotations remains unknown. Rabbit FSUs were tested using a robot testing system whose force/moment and position precision were assessed to demonstrate system capability. Flexibility testing methods were developed by load-to-failure testing in flexion/extension, axial rotation, and lateral bending. Subsequent testing methods were used to examine a 16 G needle disk puncture and No. 11 blade disk stab (positive control for mechanical disruption). Flexibility testing was used to assess segmental range-of-motion (degrees), neutral zone stiffness (N m/degrees) and width (degrees and N m), and elastic zone stiffness before and after annular injury. The robot-based system was capable of performing flexibility testing on FSUs-mean precision of force/moment measurements and robot system movements were elastic zone stiffness in flexion and lateral bending. These findings suggest that disk puncture and stab can destabilize FSUs in primary rotations.

Comparison of High-Flexion Fixed-Bearing and High-Flexion Mobile-Bearing Total Knee Arthroplasties-A Prospective Randomized Study.

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Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

2018-01-01

There is none, to our knowledge, about comparison of high-flexion fixed-bearing and high-flexion mobile-bearing total knee arthroplasties (TKAs) in the same patients. The purpose of this study was to determine whether clinical results; radiographic and computed tomographic scan results; and the survival rate of a high-flexion mobile-bearing TKA is better than that of a high-flexion fixed-bearing TKA. The present study consisted of 92 patients (184 knees) who underwent same-day bilateral TKA. Of those, 17 were men and 75 were women. The mean age at the time of index arthroplasty was 61.5 ± 8.3 years (range 52-65 years). The mean body mass index was 26.2 ± 3.3 kg/m 2 (range 23-34 kg/m 2 ). The mean follow-up was 11.2 years (range 10-12 years). The Knee Society knee scores (93 vs 92 points; P = .531) and function scores (80 vs 80 points; P = 1.000), WOMAC scores (14 vs 15 points; P = .972), and UCLA activity scores (6 vs 6 points; P = 1.000) were not different between the 2 groups at 12 years follow-up. There were no differences in any radiographic and CT scan parameters between the 2 groups. Kaplan-Meier survivorship of the TKA component was 98% (95% confidence interval, 93-100) in the high-flexion fixed-bearing TKA group and 99% (95% confidence interval, 94-100) in the high-flexion mobile-bearing TKA group 12 years after the operation. We found no benefit to mobile-bearing TKA in terms of pain, function, radiographic and CT scan results, and survivorship. Longer-term follow-up is necessary to prove the benefit of the high-flexion mobile-bearing TKA over the high-flexion fixed-bearing TKA. Copyright © 2017 Elsevier Inc. All rights reserved.

Femoral Component External Rotation Affects Knee Biomechanics: A Computational Model of Posterior-stabilized TKA.

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Kia, Mohammad; Wright, Timothy M; Cross, Michael B; Mayman, David J; Pearle, Andrew D; Sculco, Peter K; Westrich, Geoffrey H; Imhauser, Carl W

2018-01-01

The correct amount of external rotation of the femoral component during TKA is controversial because the resulting changes in biomechanical knee function associated with varying degrees of femoral component rotation are not well understood. We addressed this question using a computational model, which allowed us to isolate the biomechanical impact of geometric factors including bony shapes, location of ligament insertions, and implant size across three different knees after posterior-stabilized (PS) TKA. Using a computational model of the tibiofemoral joint, we asked: (1) Does external rotation unload the medial collateral ligament (MCL) and what is the effect on lateral collateral ligament tension? (2) How does external rotation alter tibiofemoral contact loads and kinematics? (3) Does 3° external rotation relative to the posterior condylar axis align the component to the surgical transepicondylar axis (sTEA) and what anatomic factors of the femoral condyle explain variations in maximum MCL tension among knees? We incorporated a PS TKA into a previously developed computational knee model applied to three neutrally aligned, nonarthritic, male cadaveric knees. The computational knee model was previously shown to corroborate coupled motions and ligament loading patterns of the native knee through a range of flexion. Implant geometries were virtually installed using hip-to-ankle CT scans through measured resection and anterior referencing surgical techniques. Collateral ligament properties were standardized across each knee model by defining stiffness and slack lengths based on the healthy population. The femoral component was externally rotated from 0° to 9° relative to the posterior condylar axis in 3° increments. At each increment, the knee was flexed under 500 N compression from 0° to 90° simulating an intraoperative examination. The computational model predicted collateral ligament forces, compartmental contact forces, and tibiofemoral internal/external and

The effects of gender, level of co-contraction, and initial angle on elbow extensor muscle stiffness and damping under a step increase in elbow flexion moment.

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Lee, Yunju; Ashton-Miller, James A

2011-10-01

Flexion buckling of an arm under the large ground reaction loads associated with arresting a fall to the ground increases the risk for head and thorax injuries. Yet, the factors that determine the arm buckling load remain poorly understood. We tested the hypothesis in 18 healthy young adults that neither gender, triceps co-contraction level (i.e., 25, 50, or 75% MVC) nor elbow angle would affect the rotational stiffness and damping resistance to step changes in elbow flexion loading. Data on the step response were gathered using optoelectronic markers (150 Hz) and myoelectric activity measurements (2 kHz), and an inverse dynamics analysis was used to estimate elbow extensor stiffness and damping coefficients. A repeated-measures analysis of variance showed that gender (p = 0.032), elbow flexion angle and co-contraction level (both p initial elbow flexion angle and maximum co-contraction, female stiffness and damping coefficients were 18 and 30% less, respectively, than male values after normalization by body height and weight. We conclude that the maximum extensor rotational stiffness and damping at the elbow is lower in women than in men of the same body size, and varies with triceps co-contraction level and initial elbow angle.

Constraining primordial non-Gaussianity with cosmological weak lensing: shear and flexion

International Nuclear Information System (INIS)

Fedeli, C.; Bartelmann, M.; Moscardini, L.

2012-01-01

, improves the shear constraints by ∼ 10% when added. However on such small scales the highly non-linear clustering of matter, the impact of baryonic physics, and the non-Gaussian part of the covariance matrix make any error estimation uncertain. By considering lower, and possibly more realistic, values of the flexion intrinsic shape noise results in flexion constraining power being a factor of ∼ 2 better than that of shear, and the bounds on σ 8 and f NL being improved by a factor of ∼ 3 upon their combination

Is There an Inherent Risk to Damage the Popliteus Tendon by Femoral Component With Inbuilt External Rotation? A Pilot Study in Indian Knees.

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Chouhan, Dervendra Kumar; Dhillon, Mandeep S

2016-02-01

Femoral components with inbuilt rotation require thicker flexion resection of the lateral femoral condyle and could have a potential risk of damaging the popliteus tendon, especially in the smaller Asian knees. We prospectively evaluated 10 patients with bilateral varus osteoarthritis knee to size the cuts and their location in relation to the popliteus tendon. Two different types of implant were used on either side; one side requires resection in 3° external rotation (group A) and the other side requires a femoral component with inbuilt external rotation (group B). We observed the incidence of injury to the popliteus tendon and distance between flexion cut to its attachment over the lateral femoral condyle between both groups. We had popliteus tendon injury in 3 knees all from group B. Risk of damaging the popliteus tendon was found higher in group B, as the distance between flexion cut to popliteus tendon attachment was significantly low. Femoral component with inbuilt external rotation has more risk of injuring the popliteus tendon because flexion cut takes out more bone from the lateral femoral condyle. Copyright © 2015 Elsevier Inc. All rights reserved.

Constraining primordial non-Gaussianity with cosmological weak lensing: shear and flexion

Energy Technology Data Exchange (ETDEWEB)

Fedeli, C. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Bartelmann, M. [Zentrum für Astronomie, Universität Heidelberg, Albert-Überle-Straße 2, 69120 Heidelberg (Germany); Moscardini, L., E-mail: cosimo.fedeli@astro.ufl.edu, E-mail: bartelmann@uni-heidelberg.de, E-mail: lauro.moscardini@unibo.it [Dipartimento di Astronomia, Università di Bologna, Via Ranzani 1, 40127 Bologna (Italy)

2012-10-01

being still subdominant, improves the shear constraints by ∼ 10% when added. However on such small scales the highly non-linear clustering of matter, the impact of baryonic physics, and the non-Gaussian part of the covariance matrix make any error estimation uncertain. By considering lower, and possibly more realistic, values of the flexion intrinsic shape noise results in flexion constraining power being a factor of ∼ 2 better than that of shear, and the bounds on σ{sub 8} and f{sub NL} being improved by a factor of ∼ 3 upon their combination.

Determination of a sagittal plane axis of rotation for a dynamic office chair.

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Bauer, C M; Rast, F M; Böck, C; Kuster, R P; Baumgartner, D

2018-10-01

This study investigated the location of the axis of rotation in sagittal plane movement of the spine in a free sitting condition to adjust the kinematics of a mobile seat for a dynamic chair. Dynamic office chairs are designed to avoid continuous isometric muscle activity, and to facilitate increased mobility of the back during sitting. However, these chairs incorporate increased upper body movement which could distract office workers from the performance of their tasks. A chair with an axis of rotation above the seat would facilitate a stable upper back during movements of the lower back. The selection of a natural kinematic pattern is of high importance in order to match the properties of the spine. Twenty-one participants performed four cycles of flexion and extension of the spine during an upper arm hang on parallel bars. The location of the axis of rotation relative to the seat was estimated using infrared cameras and reflective skin markers. The median axis of rotation across all participants was located 36 cm above the seat for the complete movement and 39 cm for both the flexion and extension phases, each with an interquartile range of 20 cm. There was no significant effect of the movement direction on the location of the axis of rotation and only a weak, non-significant correlation between body height and the location of the axis of rotation. Individual movement patterns explained the majority of the variance. The axis of rotation for a spinal flexion/extension movement is located above the seat. The recommended radius for a guide rail of a mobile seat is between 36 cm and 39 cm. Copyright © 2018 Elsevier Ltd. All rights reserved.

Gender differences in tibio-femoral kinematics and quadriceps muscle force during weight-bearing knee flexion in vitro.

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Wünschel, Markus; Wülker, Nikolaus; Müller, Otto

2013-11-01

Females have a higher risk in terms of anterior cruciate ligament injuries during sports than males. Reasons for this fact may be different anatomy and muscle recruitment patterns leading to less protection for the cruciate- and collateral-ligaments. This in vitro study aims to evaluate gender differences in knee joint kinematics and muscle force during weight-bearing knee flexions. Thirty-four human knee specimens (17 females/17 males) were mounted on a dynamic knee simulator. Weight-bearing single-leg knee flexions were performed with different amounts of simulated body weight (BW). Gender-specific kinematics was measured with an ultrasonic motion capture system and different loading conditions were examined. Knee joint kinematics did not show significant differences regarding anteroposterior and medial-lateral movement as well as tibial varus-valgus and internal-external rotation. This applied to all simulated amounts of BW. Simulating 100 N BW in contrast to AF50 led to a significant higher quadriceps overall force in female knees from 45° to 85° of flexion in contrast to BW 50 N. In these female specimens, the quadriceps overall force was about 20 % higher than in male knees being constant in higher flexion angles. It is indicated by our results that in a squatting movement females compared with males produce higher muscle forces, suggesting an increased demand for muscular stabilization, whereas tibio-femoral kinematics was similar for both genders.

Postoperative stiff shoulder after open rotator cuff repair: a 3- to 20-year follow-up study.

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Vastamäki, H; Vastamäki, M

2014-12-01

Stiffness after a rotator cuff tear is common. So is stiffness after an arthroscopic rotator cuff repair. In the literature, however, postoperative restriction of passive range of motion after open rotator cuff repair in shoulders with free passive range of motion at surgery has seldom been recognized. We hypothesize that this postoperative stiffness is more frequent than recognized and slows the primary postoperative healing after a rotator cuff reconstruction. We wondered how common is postoperative restriction of both active and passive range of motion after open rotator cuff repair in shoulders with free passive preoperative range of motion, how it recovers, and whether this condition influences short- and long-term results of surgery. We also explored factors predicting postoperative shoulder stiffness. We retrospectively identified 103 postoperative stiff shoulders among 416 consecutive open rotator cuff repairs, evaluating incidence and duration of stiffness, short-term clinical results and long-term range of motion, pain relief, shoulder strength, and functional results 3-20 (mean 8.7) years after surgery in 56 patients. The incidence of postoperative shoulder stiffness was 20%. It delayed primary postoperative healing by 3-6 months and resolved during a mean 6.3 months postoperatively. External rotation resolved first, corresponding to that of the controls at 3 months; flexion and abduction took less than 1 year after surgery. The mean summarized range of motion (flexion + abduction + external rotation) increased as high as 93% of the controls' range of motion by 6 months and 100% by 1 year. Flexion, abduction, and internal rotation improved to the level of the contralateral shoulders as did pain, strength, and function. Age at surgery and condition of the biceps tendon were related to postoperative stiffness. Postoperative stiff shoulder after open rotator cuff repair is a common complication resolving in 6-12 months with good long-term results. © The

Balancing fast-rotating parts of hand-held machine drive

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Korotkov, V. S.; Sicora, E. A.; Nadeina, L. V.; Yongzheng, Wang

2018-03-01

The article considers the issues related to the balancing of fast rotating parts of the hand-held machine drive including a wave transmission with intermediate rolling elements, which is constructed on the basis of the single-phase collector motor with a useful power of 1 kW and a nominal rotation frequency of 15000 rpm. The forms of balancers and their location are chosen. The method of balancing is described. The scheme for determining of residual unbalance in two correction planes is presented. Measurement results are given in tables.

Design of a wearable hand exoskeleton for exercising flexion/extension of the fingers.

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Jo, Inseong; Lee, Jeongsoo; Park, Yeongyu; Bae, Joonbum

2017-07-01

In this paper, design of a wearable hand exoskeleton system for exercising flexion/extension of the fingers, is proposed. The exoskeleton was designed with a simple and wearable structure to aid finger motions in 1 degree of freedom (DOF). A hand grasping experiment by fully-abled people was performed to investigate general hand flexion/extension motions and the polynomial curve of general hand motions was obtained. To customize the hand exoskeleton for the user, the polynomial curve was adjusted to the joint range of motion (ROM) of the user and the optimal design of the exoskeleton structure was obtained using the optimization algorithm. A prototype divided into two parts (one part for the thumb, the other for rest fingers) was actuated by only two linear motors for compact size and light weight.

In vivo metacarpophalanageal joint collateral ligament length changes during flexion.

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Sun, Y C; Sheng, X M; Chen, J; Qian, Z W

2017-07-01

We investigated the in vivo length changes of the collateral ligaments of metacarpophalangeal joint during flexion. We obtained computed tomography scans of index, middle, ring and little fingers at 0°, 30°, 60° and 90° of joint flexion from six hands of six healthy adult volunteers. Three of them had their dominant right hand studied, and the other three had their non-dominant left hand studied. We measured and analysed the radial and ulnar collateral ligaments of each metacarpophalangeal joint from the reconstructed images. We found that the dorsal and middle portions of the both radial and ulnar collateral ligament lengthened progressively during digital flexion and reached the maximum at 90° flexion. The length of the volar portion increased from 0° to 30° flexion and then decreased from 30° to 60° flexion, reaching the minimum at 90°. In conclusion, three portions of collateral ligaments on both sides of the metacarpophalangeal joint have variable length changes during flexion, which act to stabilize the joint through its flexion arc.

Adult Hip Flexion Contracture due to Neurological Disease: A New Treatment Protocol-Surgical Treatment of Neurological Hip Flexion Contracture.

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Nicodemo, Alberto; Arrigoni, Chiara; Bersano, Andrea; Massè, Alessandro

2014-01-01

Congenital, traumatic, or extrinsic causes can lead people to paraplegia; some of these are potentially; reversible and others are not. Paraplegia can couse hip flexion contracture and, consequently, pressure sores, scoliosis, and hyperlordosis; lumbar and groin pain are strictly correlated. Scientific literature contains many studies about children hip flexion related to neurological diseases, mainly caused by cerebral palsy; only few papers focus on this complication in adults. In this study we report our experience on surgical treatment of adult hip flexion contracture due to neurological diseases; we have tried to outline an algorithm to choose the best treatment avoiding useless or too aggressive therapies. We present 5 cases of adult hips flexion due to neurological conditions treated following our algorithm. At 1-year-follow-up all patients had a good clinical outcome in terms of hip range of motion, pain and recovery of walking if possible. In conclusion we think that this algorithm could be a good guideline to treat these complex cases even if we need to treat more patients to confirm this theory. We believe also that postoperation physiotherapy it is useful in hip motility preservation, improvement of muscular function, and walking ability recovery when possible.

Biomechanical Considerations in the Design of High-Flexion Total Knee Replacements

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Cheng-Kung Cheng

2014-01-01

Full Text Available Typically, joint arthroplasty is performed to relieve pain and improve functionality in a diseased or damaged joint. Total knee arthroplasty (TKA involves replacing the entire knee joint, both femoral and tibial surfaces, with anatomically shaped artificial components in the hope of regaining normal joint function and permitting a full range of knee flexion. In spite of the design of the prosthesis itself, the degree of flexion attainable following TKA depends on a variety of factors, such as the joint’s preoperative condition/flexion, muscle strength, and surgical technique. High-flexion knee prostheses have been developed to accommodate movements that require greater flexion than typically achievable with conventional TKA; such high flexion is especially prevalent in Asian cultures. Recently, computational techniques have been widely used for evaluating the functionality of knee prostheses and for improving biomechanical performance. To offer a better understanding of the development and evaluation techniques currently available, this paper aims to review some of the latest trends in the simulation of high-flexion knee prostheses.

The effect of internal mould water spray cooling on rotationally moulded polyethylene parts

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McCourt, Mark P.; Kearns, Mark P.; Martin, Peter J.

2018-05-01

The conventional method of cooling during the rotational moulding process is through the use of forced air. During the cooling phase of a typical rotomoulding cycle, large volumes of high velocity room temperature air are forced across the outside of the rotating rotomoulding tool to encourage cooling of the metal mould and molten polymer. Since no cooling is applied to the inside of the mould, the inner surface of the polymer (polyethylene) cools more slowly and will have a tendency to be more crystalline and the polyethylene will have a higher density in this region. The side that cools more quickly (in contact with the inside mould wall) will be less crystalline, and will therefore have a lower density. The major consequence of this difference in crystallinity will be a buildup of internal stresses producing warpage and excessive shrinkage of the part with subsequent increased levels of scrap. Therefore excessive cooling on the outside of the mould should be avoided. One consequence of this effect is that the cooling time for a standard rotationally moulded part can be quite long and this has an effect on the overall economics of the process in terms of part manufacture. A number of devices are currently on the market to enhance the cooling of rotational moulding by introducing a water spray to the inside of the rotomoulding during cooling. This paper reports on one such device 'Rotocooler' which during a series of initial industrial trials has been shown to reduce the cycletime by approximately 12 to 16%, with minimal effect on the mechanical properties, leading to a part which has less warpage and shrinkage than a conventionally cooled part.

Relationship Between Force Production During Isometric Squats and Knee Flexion Angles During Landing.

Science.gov (United States)

Fisher, Harry; Stephenson, Mitchell L; Graves, Kyle K; Hinshaw, Taylour J; Smith, Derek T; Zhu, Qin; Wilson, Margaret A; Dai, Boyi

2016-06-01

Decreased knee flexion angles during landing are associated with increased anterior cruciate ligament loading. The underlying mechanisms associated with decreased self-selected knee flexion angles during landing are still unclear. The purpose of this study was to establish the relationship between the peak force production at various knee flexion angles (35, 55, 70, and 90°) during isometric squats and the actual knee flexion angles that occur during landing in both men and women. A total of 18 men and 18 women recreational/collegiate athletes performed 4 isometric squats at various knee flexion angles while vertical ground reaction forces were recorded. Participants also performed a jump-landing-jump task while lower extremity kinematics were collected. For women, significant correlations were found between the peak force production at 55 and 70° of knee flexion during isometric squats and the knee flexion angle at initial contact of landing. There were also significant correlations between the peak force production at 55, 70, and 90° of knee flexion during isometric squats and the peak knee flexion angle during landing. These correlations tended to be stronger during isometric squats at greater knee flexion compared with smaller knee flexion. No significant correlations were found for men. Posture-specific strength may play an important role in determining self-selected knee flexion angles during landing for women.

Plantar-flexion of the ankle joint complex in terminal stance is initiated by subtalar plantar-flexion: A bi-planar fluoroscopy study.

Science.gov (United States)

Koo, Seungbum; Lee, Kyoung Min; Cha, Young Joo

2015-10-01

Gross motion of the ankle joint complex (AJC) is a summation of the ankle and subtalar joints. Although AJC kinematics have been widely used to evaluate the function of the AJC, the coordinated movements of the ankle and subtalar joints are not well understood. The purpose of this study was to accurately quantify the individual kinematics of the ankle and subtalar joints in the intact foot during ground walking by using a bi-planar fluoroscopic system. Bi-planar fluoroscopic images of the foot and ankle during walking and standing were acquired from 10 healthy subjects. The three-dimensional movements of the tibia, talus, and calcaneus were calculated with a three-dimensional/two-dimensional registration method. The skeletal kinematics were quantified from 9% to 86% of the full stance phase because of the limited camera speed of the X-ray system. At the beginning of terminal stance, plantar-flexion of the AJC was initiated in the subtalar joint on average at 75% ranging from 62% to 76% of the stance phase, and plantar-flexion of the ankle joint did not start until 86% of the stance phase. The earlier change to plantar-flexion in the AJC than the ankle joint due to the early plantar-flexion in the subtalar joint was observed in 8 of the 10 subjects. This phenomenon could be explained by the absence of direct muscle insertion on the talus. Preceding subtalar plantar-flexion could contribute to efficient and stable ankle plantar-flexion by locking the midtarsal joint, but this explanation needs further investigation. Copyright © 2015 Elsevier B.V. All rights reserved.

Adult Hip Flexion Contracture due to Neurological Disease: A New Treatment Protocol—Surgical Treatment of Neurological Hip Flexion Contracture

OpenAIRE

Nicodemo, Alberto; Arrigoni, Chiara; Bersano, Andrea; Massè, Alessandro

2014-01-01

Congenital, traumatic, or extrinsic causes can lead people to paraplegia; some of these are potentially; reversible and others are not. Paraplegia can couse hip flexion contracture and, consequently, pressure sores, scoliosis, and hyperlordosis; lumbar and groin pain are strictly correlated. Scientific literature contains many studies about children hip flexion related to neurological diseases, mainly caused by cerebral palsy; only few papers focus on this complication in adults. In this stu...

Micromechanics of the human vertebral body for forward flexion.

Science.gov (United States)

Yang, Haisheng; Nawathe, Shashank; Fields, Aaron J; Keaveny, Tony M

2012-08-09

To provide mechanistic insight into the etiology of osteoporotic wedge fractures, we investigated the spatial distribution of tissue at the highest risk of initial failure within the human vertebral body for both forward flexion and uniform compression loading conditions. Micro-CT-based linear elastic finite element analysis was used to virtually load 22 human T9 vertebral bodies in either 5° of forward flexion or uniform compression; we also ran analyses replacing the simulated compliant disc (E=8 MPa) with stiff polymethylmethacrylate (PMMA, E=2500 MPa). As expected, we found that, compared to uniform compression, forward flexion increased the overall endplate axial load on the anterior half of the vertebra and shifted the spatial distribution of high-risk tissue within the vertebra towards the anterior aspect of the vertebral body. However, despite that shift, the high-risk tissue remained primarily within the central regions of the trabecular bone and endplates, and forward flexion only slightly altered the ratio of cortical-to-trabecular load sharing at the mid-vertebral level (mean±SD for n=22: 41.3±7.4% compression; 44.1±8.2% forward flexion). When the compliant disc was replaced with PMMA, the anterior shift of high-risk tissue was much more severe. We conclude that, for a compliant disc, a moderate degree of forward flexion does not appreciably alter the spatial distribution of stress within the vertebral body. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extrinsic versus intrinsic hand muscle dominance in finger flexion.

Science.gov (United States)

Al-Sukaini, A; Singh, H P; Dias, J J

2016-05-01

This study aims to identify the patterns of dominance of extrinsic or intrinsic muscles in finger flexion during initiation of finger curl and mid-finger flexion. We recorded 82 hands of healthy individuals (18-74 years) while flexing their fingers and tracked the finger joint angles of the little finger using video motion tracking. A total of 57 hands (69.5%) were classified as extrinsic dominant, where the finger flexion was initiated and maintained at proximal interphalangeal and distal interphalangeal joints. A total of 25 (30.5%) were classified as intrinsic dominant, where the finger flexion was initiated and maintained at the metacarpophalangeal joint. The distribution of age, sex, dominance, handedness and body mass index was similar in the two groups. This knowledge may allow clinicians to develop more efficient rehabilitation regimes, since intrinsic dominant individuals would not initiate extrinsic muscle contraction till later in finger flexion, and might therefore be allowed limited early active motion. For extrinsic dominant individuals, by contrast, initial contraction of extrinsic muscles would place increased stress on the tendon repair site if early motion were permitted. © The Author(s) 2016.

Adult Hip Flexion Contracture due to Neurological Disease: A New Treatment Protocol—Surgical Treatment of Neurological Hip Flexion Contracture

Directory of Open Access Journals (Sweden)

Alberto Nicodemo

2014-01-01

Full Text Available Congenital, traumatic, or extrinsic causes can lead people to paraplegia; some of these are potentially; reversible and others are not. Paraplegia can couse hip flexion contracture and, consequently, pressure sores, scoliosis, and hyperlordosis; lumbar and groin pain are strictly correlated. Scientific literature contains many studies about children hip flexion related to neurological diseases, mainly caused by cerebral palsy; only few papers focus on this complication in adults. In this study we report our experience on surgical treatment of adult hip flexion contracture due to neurological diseases; we have tried to outline an algorithm to choose the best treatment avoiding useless or too aggressive therapies. We present 5 cases of adult hips flexion due to neurological conditions treated following our algorithm. At 1-year-follow-up all patients had a good clinical outcome in terms of hip range of motion, pain and recovery of walking if possible. In conclusion we think that this algorithm could be a good guideline to treat these complex cases even if we need to treat more patients to confirm this theory. We believe also that postoperation physiotherapy it is useful in hip motility preservation, improvement of muscular function, and walking ability recovery when possible.

Adult Hip Flexion Contracture due to Neurological Disease: A New Treatment Protocol—Surgical Treatment of Neurological Hip Flexion Contracture

Science.gov (United States)

Nicodemo, Alberto; Arrigoni, Chiara; Bersano, Andrea; Massè, Alessandro

2014-01-01

Congenital, traumatic, or extrinsic causes can lead people to paraplegia; some of these are potentially; reversible and others are not. Paraplegia can couse hip flexion contracture and, consequently, pressure sores, scoliosis, and hyperlordosis; lumbar and groin pain are strictly correlated. Scientific literature contains many studies about children hip flexion related to neurological diseases, mainly caused by cerebral palsy; only few papers focus on this complication in adults. In this study we report our experience on surgical treatment of adult hip flexion contracture due to neurological diseases; we have tried to outline an algorithm to choose the best treatment avoiding useless or too aggressive therapies. We present 5 cases of adult hips flexion due to neurological conditions treated following our algorithm. At 1-year-follow-up all patients had a good clinical outcome in terms of hip range of motion, pain and recovery of walking if possible. In conclusion we think that this algorithm could be a good guideline to treat these complex cases even if we need to treat more patients to confirm this theory. We believe also that postoperation physiotherapy it is useful in hip motility preservation, improvement of muscular function, and walking ability recovery when possible. PMID:24707293

Rites thérapeutiques : réflexion sur le terrain et les archives

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Chantal Radimilahy

2008-08-01

Full Text Available Rites thérapeutiques : réflexion sur le terrain et les archives. En comparant la façon dont l’écrit sert à noter et à fixer des pratiques de guérissage, d’une part dans les archives de L. Vig et d’autre part dans les carnets d’un guérisseur malgache contemporain, l’auteur esquisse une réflexion sur la stabilité apparente des formes du langage et des pratiques rituelles dans un contexte social transformé.Therapeutic rituals: consideration on fieldwork and archives. By comparing the way in which writing is used to record and establish traditional healing practices, on the one hand in the archives of L. Vig and on the other, in the notes of a contemporary Madagascan traditional healer, the author outlines her reflections on the apparent stability of language forms and ritual practices in a transformed social context.

Relative sensitivity of depth discrimination for ankle inversion and plantar flexion movements.

Science.gov (United States)

Black, Georgia; Waddington, Gordon; Adams, Roger

2014-02-01

25 participants (20 women, 5 men) were tested for sensitivity in discrimination between sets of six movements centered on 8 degrees, 11 degrees, and 14 degrees, and separated by 0.3 degrees. Both inversion and plantar flexion movements were tested. Discrimination of the extent of inversion movement was observed to decline linearly with increasing depth; however, for plantar flexion, the discrimination function for movement extent was found to be non-linear. The relatively better discrimination of plantar flexion movements than inversion movements at around 11 degrees from horizontal is interpreted as an effect arising from differential amounts of practice through use, because this position is associated with the plantar flexion movement made in normal walking. The fact that plantar flexion movements are discriminated better than inversion at one region but not others argues against accounts of superior proprioceptive sensitivity for plantar flexion compared to inversion that are based on general properties of plantar flexion such as the number of muscle fibres on stretch.

Balanced Flexion and Extension Gaps Are Not Always of Equal Size.

Science.gov (United States)

Kinsey, Tracy L; Mahoney, Ormonde M

2018-04-01

It has been widely accepted in total knee arthroplasty (TKA) that flexion and extension gaps in the disarticulated knee during surgery should be equalized. We hypothesized that tensioning during assessment of the flexion gap can induce temporary widening of the gap due to posterior tibial translation. We aimed to describe posterior tibial translation at flexion gap (90°) assessments and assess the correlation of tibial translation with laxity (flexion space increase) using constrained and non-constrained inserts. Imageless navigation was used to measure flexion angle, tibial position relative to the femoral axis, and lateral/medial laxity in 30 patients undergoing primary TKA. Trialing was conducted using posteriorly stabilized and cruciate retaining trials of the same size to elucidate the association of posterior tibial translation with changes in joint capsule laxity at 90° knee flexion. All patients demonstrated posterior tibial translation during flexion gap assessment relative to their subsequent final implantation [mean ± standard deviation (range), 11.3 ± 4.4 (4-21) mm]. Positive linear correlation [r = 0.69, 95% confidence interval (CI) 0.44-0.84, P ≤ .001] was demonstrated between translations [8.7 ± 2.4 (3-13) mm] and laxity changes [2.9° ± 2.0° (-0.7° to 7.4°)] at 90° of flexion. Posterior tibial translation can cause artifactual widening of the flexion gap during gap balancing in posteriorly stabilized TKA, which can be of sufficient magnitude to alter femoral component size selection for some patients. Recognition and management of these intra-operative dynamics for optimal kinematics could be feasible with the advent of robotic applications. Copyright © 2017 Elsevier Inc. All rights reserved.

MR assessment of movement and morphologic change in the menisci during knee flexion

International Nuclear Information System (INIS)

Kawahara, Y.; Uetani, M.; Fuchi, K.; Eguchi, H.; Hayashi, K.

1999-01-01

To examine movement and morphologic alteration in the menisci during knee flexion. Twenty healthy knees were imaged at 0 degrees, 45 degrees, and 90 degrees of passive non-weight-bearing flexion in the sagittal plane with MR. In each meniscus, posterior movement distance during knee flexion and the ratio of anteroposterior (a.p.) diameter at flexion to that at extension were calculated. Each meniscus moved posteriorly during knee flexion. Movement was greater in the anterior horn than in the posterior horn, and greater in the medial meniscus than in the lateral meniscus (p<0.05). The a.p. diameter of each meniscus was reduced at flexion (p<0.05). Knee flexion normally leads to posterior movement and shortening of the a.p. diameter of the menisci, which may be related to the positioning and curvature of femoral condyles at the femorotibial contact point at knee flexion

MR assessment of movement and morphologic change in the menisci during knee flexion

International Nuclear Information System (INIS)

Kawahara, Y.; Uetani, M.; Hayashi, K.; Fuchi, K.; Eguchi, H.

1999-01-01

Purpose: To examine movement and morphologic alteration in the menisci during knee flexion. Material and Methods: Twenty healthy knees were imaged at 0 , 45 , and 90 of passive non-weight-bearing flexion in the sagittal plane with MR. In each meniscus, posterior movement distance during knee flexion and the ratio of anteroposterior (a.p.) diameter at flexion to that at extension were calculated. Results: Each meniscus moved posteriorly during knee flexion. Movement was greater in the anterior horn than in the posterior horn, and greater in the medial meniscus than in the lateral meniscus (p<0.05). The a.p. diameter of each meniscus was reduced at flexion (p<0.05). Conclusion: Knee flexion normally leads to posterior movement and shortening of the a.p. diameter of the menisci, which may be related to the positioning and curvature of femoral condyles at the femorotibial contact point at knee flexion. (orig.)

Correlation between the elbow flexion and the hand and wrist flexion after neurotization of the fascicles of the ulnar nerve to the motor branch to the biceps

Directory of Open Access Journals (Sweden)

Ricardo Boso Escudero

Full Text Available ABSTRACT OBJECTIVE: Gain in elbow flexion in patients with brachial plexus injury is extremely important. The transfer of a fascicle from the ulnar nerve to the motor branch of the musculocutaneous nerve (Oberlin surgery is a treatment option. However, in some patients, gain in elbow flexion is associated with wrist and finger flexion. This study aimed to assess the frequency of this association and the functional behavior of the limb. METHODS: Case-control study of 18 patients who underwent the Oberlin surgery. Group 1 included patients without disassociation of range of elbow flexion and that of the fingers and wrist; Group 2 included patients in whom this disassociation was present. In the functional evaluation, the Sollerman and DASH tests were used. RESULTS: It was observed that 38.89% of the patients did not present disassociation of elbow flexion with flexion of the wrist and fingers. Despite the existence of a favorable difference in the group with disassociation of the movement, when the Sollerman protocol was applied to the comparison between both groups, this difference was not statistically significant. With the DASH test, however, there was a statistically significant difference in favor of the group of patients who managed to disassociate the movement. CONCLUSION: The association of elbow flexion with flexion of the wrist and fingers, in the group studied, was shown to be a frequent event, which influenced the functional result of the affected limb.

Effects of upright weight bearing and the knee flexion angle on patellofemoral indices using magnetic resonance imaging in patients with patellofemoral instability.

Science.gov (United States)

Becher, Christoph; Fleischer, Benjamin; Rase, Marten; Schumacher, Thees; Ettinger, Max; Ostermeier, Sven; Smith, Tomas

2017-08-01

This study analysed the effects of upright weight bearing and the knee flexion angle on patellofemoral indices, determined using magnetic resonance imaging (MRI), in patients with patellofemoral instability (PI). Healthy volunteers (control group, n = 9) and PI patients (PI group, n = 16) were scanned in an open-configuration MRI scanner during upright weight bearing and supine non-weight bearing positions at full extension (0° flexion) and at 15°, 30°, and 45° flexion. Patellofemoral indices included the Insall-Salvati Index, Caton-Deschamp Index, and Patellotrochlear Index (PTI) to determine patellar height and the patellar tilt angle (PTA), bisect offset (BO), and the tibial tubercle-trochlear groove (TT-TG) distance to assess patellar rotation and translation with respect to the femur and alignment of the extensor mechanism. A significant interaction effect of weight bearing by flexion angle was observed for the PTI, PTA, and BO for subjects with PI. At full extension, post hoc pairwise comparisons revealed a significant effect of weight bearing on the indices, with increased patellar height and increased PTA and BO in the PI group. Except for the BO, no such changes were seen in the control group. Independent of weight bearing, flexing the knee caused the PTA, BO, and TT-TG distance to be significantly reduced. Upright weight bearing and the knee flexion angle affected patellofemoral MRI indices in PI patients, with significantly increased values at full extension. The observations of this study provide a caution to be considered by professionals when treating PI patients. These patients should be evaluated clinically and radiographically at full extension and various flexion angles in context with quadriceps engagement. Explorative case-control study, Level III.

Rotating electric machine with fluid supported parts

Science.gov (United States)

Smith, Jr., Joseph L.; Kirtley, Jr., James L.

1981-01-01

A rotating electric machine in which the armature winding thereof and other parts are supported by a liquid to withstand the mechanical stresses applied during transient overloads and the like. In particular, a narrow gap is provided between the armature winding and the stator which supports it and this gap is filled with an externally pressurized viscous liquid. The liquid is externally pressurized sufficiently to balance the static loads on the armature winding. Transient mechanical loads which deform the armature winding alter the gap dimensions and thereby additionally pressurize the viscous liquid to oppose the armature winding deformation and more nearly uniformly to distribute the resulting mechanical stresses.

Spontaneous Improvement of Compensatory Knee Flexion After Surgical Correction of Mismatch Between Pelvic Incidence and Lumbar Lordosis.

Science.gov (United States)

Cheng, Xiaofei; Zhang, Feng; Wu, Jigong; Zhu, Zhenan; Dai, Kerong; Zhao, Jie

2016-08-15

A retrospective study. The aim of this study was to investigate the correlation between pelvic incidence (PI) and lumbar lordosis (LL) mismatch and knee flexion during standing in patients with lumbar degenerative diseases and to examine the effects of surgical correction of the PI-LL mismatch on knee flexion. Only several studies focused on knee flexion as a compensatory mechanism of the PI-LL mismatch. Little information is currently available on the effects of lumbar correction on knee flexion in patients with the PI-LL mismatch. A group of patients with lumbar degenerative diseases were divided into PI-LL match group (PI-LL ≤ 10°) and PI-LL mismatch group (PI-LL > 10°). A series of radiographic parameters and knee flexion angle (KFA) were compared between the two groups. The PI-LL mismatch group was further subdivided into operative and nonoperative group. The changes in KFA with PI-LL were examined. The PI-LL mismatch group exhibited significantly greater sagittal vertical axis (SVA), pelvic tilt (PT) and KFA, and smaller LL, thoracic kyphosis (TK), and sacral slope than the PI-LL match group. PI-LL, LL, PI, SVA, and PT were significantly correlated with KFA in the PI-LL mismatch group. From baseline to 6-month follow-up, all variables were significantly different in the operative group with the exception of PI, although there was no significant difference in any variable in the nonoperative group. The magnitude of surgical correction in the PI-LL mismatch was significantly correlated with the degree of spontaneous changes in KFA, PT, and TK. The PI-LL mismatch would contribute to compensatory knee flexion during standing in patients with lumbar degenerative disease. Surgical correction of the PI-LL mismatch could lead to a spontaneous improvement of compensatory knee flexion. The degree of improvement in knee flexion depends in part on the amount of correction in the PI-LL mismatch. 3.

Fatigue Analysis of Rotating Parts. A Case Study for a Belt Driven Pulley

Science.gov (United States)

Sandu, Ionela; Tabacu, Stefan; Ducu, Catalin

2017-10-01

The present study is focused on the life estimation of a rotating part as a component of an engine assembly namely the pulley of the coolant pump. The goal of the paper is to develop a model, supported by numerical analysis, capable to predict the lifetime of the part. Starting from functional drawing, CAD Model and technical specifications of the part a numerical model was developed. MATLAB code was used to develop a tool to apply the load over the selected area. The numerical analysis was performed in two steps. The first simulation concerned the inertia relief due to rotational motion about the shaft (of the pump). Results from this simulation were saved and the stress - strain state used as initial conditions for the analysis with the load applied. The lifetime of a good part was estimated. A defect was created in order to investigate the influence over the working requirements. It was found that there is little influence with respect to the prescribed lifetime.

Posterior-anterior weight-bearing radiograph in 15 knee flexion in medial osteoarthritis

International Nuclear Information System (INIS)

Yamanaka, Norio; Takahashi, Toshiaki; Yamamoto, Hiroshi; Ichikawa, Norikazu

2003-01-01

To evaluate the degree of knee flexion at which: (1) degenerative joint space narrowing is best seen, (2) the tibial plateau is best visualized and (3) the tibiofemoral angle is most correct, in order to assess the degree of flexion in the anteroposterior radiographic view that is most useful for assessing medial compartment osteoarthritis (OA) of the knee.Design and patients. We compared the conventional extended view of the knee and views at 15 , 30 , and 45 of flexion with respect to joint space narrowing, alignment of the medial tibial plateau (MTP), and tibiofemoral angles in 113 knees of 95 patients with medial osteoarthritis of the knee (22 men, 73 women; mean age 67 years).Results. At the midpoint and the narrowest point of the medial compartment, joint space narrowing values at 15 , 30 , and 45 of flexion of the knee were smaller than that of the conventional extended view. Superimposition of the margins of the tibial plateau was satisfactory in 12% of patients in the conventional extended view, in 36% at 15 of flexion, in 20% at 30 of flexion, and in 19% at 45 of flexion of the knee. When the knee was at 15 of flexion there was a smaller difference in the tibiofemoral angle, in comparison with the knee extended, than was the case at 30 and 45 of flexion in patients with medial OA.Conclusion. A posteroanterior view with 15 of flexion of the knee was able to detect joint space narrowing accurately, to achieve good alignment of the MTP in the medial compartment, and to reduce the difference in tibiofemoral angle compared with a view of the knee in conventional extension, and may be an alternative view in cases of medial OA of the knee. (orig.)

Elbow joint stability in relation to forced external rotation

DEFF Research Database (Denmark)

Deutch, S.R.; Jensen, S.L.; Olsen, B.S.

2003-01-01

The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation. The osse......The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation...... external forearm rotation until the point of maximal torque decreased from a maximum in full extension to a minimum at 30 degrees of elbow flexion (P =.03). The elbow in a slightly flexed position, varus stress, and forearm external rotation trauma might be the important biomechanical factors...

Biomechanical analysis of posterior cruciate ligament retaining high-flexion total knee arthroplasty

NARCIS (Netherlands)

Zelle, J.; van der Zanden, A.C.; De Waal Malefijt, M.; Verdonschot, Nicolaas Jacobus Joseph

2009-01-01

Background High-flexion knee replacements have been developed to accommodate a large range of flexion (>120°) after total knee arthroplasty. Both posterior cruciate ligament retaining and sacrificing high-flexion knee designs have been marketed. The main objective of this study was to evaluate the

A restrained-torque-based motion instructor: forearm flexion/extension-driving exoskeleton

Science.gov (United States)

Nishimura, Takuya; Nomura, Yoshihiko; Sakamoto, Ryota

2013-01-01

When learning complicated movements by ourselves, we encounter such problems as a self-rightness. The self-rightness results in a lack of detail and objectivity, and it may cause to miss essences and even twist the essences. Thus, we sometimes fall into the habits of doing inappropriate motions. To solve these problems or to alleviate the problems as could as possible, we have been developed mechanical man-machine human interfaces to support us learning such motions as cultural gestures and sports form. One of the promising interfaces is a wearable exoskeleton mechanical system. As of the first try, we have made a prototype of a 2-link 1-DOF rotational elbow joint interface that is applied for teaching extension-flexion operations with forearms and have found its potential abilities for teaching the initiating and continuing flection motion of the elbow.

Modelling knee flexion effects on joint power absorption and adduction moment.

Science.gov (United States)

Nagano, Hanatsu; Tatsumi, Ichiroh; Sarashina, Eri; Sparrow, W A; Begg, Rezaul K

2015-12-01

Knee osteoarthritis is commonly associated with ageing and long-term walking. In this study the effects of flexing motions on knee kinetics during stance were simulated. Extended knees do not facilitate efficient loading. It was therefore, hypothesised that knee flexion would promote power absorption and negative work, while possibly reducing knee adduction moment. Three-dimensional (3D) position and ground reaction forces were collected from the right lower limb stance phase of one healthy young male subject. 3D position was sampled at 100 Hz using three Optotrak Certus (Northern Digital Inc.) motion analysis camera units, set up around an eight metre walkway. Force plates (AMTI) recorded ground reaction forces for inverse dynamics calculations. The Visual 3D (C-motion) 'Landmark' function was used to change knee joint positions to simulate three knee flexion angles during static standing. Effects of the flexion angles on joint kinetics during the stance phase were then modelled. The static modelling showed that each 2.7° increment in knee flexion angle produced 2.74°-2.76° increments in knee flexion during stance. Increased peak extension moment was 6.61 Nm per 2.7° of increased knee flexion. Knee flexion enhanced peak power absorption and negative work, while decreasing adduction moment. Excessive knee extension impairs quadriceps' power absorption and reduces eccentric muscle activity, potentially leading to knee osteoarthritis. A more flexed knee is accompanied by reduced adduction moment. Research is required to determine the optimum knee flexion to prevent further damage to knee-joint structures affected by osteoarthritis. Copyright © 2015 Elsevier B.V. All rights reserved.

Spine lateral flexion strength development differences between exercises with pelvic stabilization and without pelvic stabilization

Science.gov (United States)

Straton, Alexandru; Gidu, Diana Victoria; Micu, Alexandru

2015-02-01

Poor lateral flexor muscle strength can be an important source of lumbar/thoracic back pain in women. The purpose of this study was to evaluate pelvic stabilization (PS) and no pelvic stabilization (NoPS) lateral flexion strength exercise training on the development of isolated right and left lateral flexion strength. Isometric torque of the isolated right and left lateral flexion muscles was measured at two positions (0° and 30° opposed angle range of motion) on 42 healthy women before and after 8 weeks of PS and NoPS lateral flexion strength exercise training. Subjects were assigned in three groups, the first (n=14) trained 3 times/week with PS lateral flexion strength exercise, the second (n=14) trained 3 times/week with NoPS lateral flexion strength exercise and the third (control, n=14) did not train. Post training isometric strength values describing PS and NoPS lateral flexion strength improved in greater extent for the PS lateral flexion strength exercise group and in lesser extent for the NoPS lateral flexion strength exercise group, in both angles (pstrength exercises; NoPS lateral flexion strength exercises can be an effective way of training for the spine lateral flexion muscles, if there is no access to PS lateral flexion strength training machines.

Serial casting for elbow flexion contractures in neonatal brachial plexus palsy.

Science.gov (United States)

Duijnisveld, B J; Steenbeek, D; Nelissen, R G H H

2016-09-02

The objective of this study was to evaluate the effectiveness of serial casting of elbow flexion contractures in neonatal brachial plexus palsy. A prospective consecutive cohort study was performed with a median follow-up of 5 years. Forty-one patients with elbow flexion contractures ≥ 30° were treated with serial casting until the contracture was ≤ 10°, for a maximum of 8 weeks. Range of motion, number of recurrences and patient satisfaction were recorded and analyzed using Wilcoxon signed-rank and Cox regression tests. Passive extension increased from a median of -40° (IQR -50 to -30) to -15° (IQR -10 to -20, p casting had to be prematurely replaced by night splinting due to complaints. Serial casting improved elbow flexion contractures, although recurrences were frequent. The severity of elbow flexion contracture is a predictor of recurrence. We recommend more research on muscle degeneration and determinants involved in elbow flexion contractures to improve treatment strategies and prevent side-effects.

Sideflexion induced lumbar spine conjunct rotation and its influencing factors.

Science.gov (United States)

Vicenzino, G; Twomey, L

1993-01-01

Twenty motion segments from four male post mortem subjects with a mean age of 29 years were moved into the lumbar spine test positions of extension/left sideflexion, extension/right sideflexion, flexion/left sideflexion and flexion/right sideflexion Jheconjunct rotation (CR) that occurred was measured from a photographic record. The results indicated that the direction of the CR of the whole lumbar spine (ie between L1 and S1) was significantly different between the flexed and extended lumbar spine position. The direction of the CR was also significantly different between the different intervertebral motion segment levels. There was no relationship between CR and zygapophyseal joint geometry or intervertebral disc degeneration. Copyright © 1993 Australian Physiotherapy Association. Published by . All rights reserved.

Neuromuscular Activation of the Vastus Intermedius Muscle during Isometric Hip Flexion.

Directory of Open Access Journals (Sweden)

Akira Saito

Full Text Available Although activity of the rectus femoris (RF differs from that of the other synergists in quadriceps femoris muscle group during physical activities in humans, it has been suggested that the activation pattern of the vastus intermedius (VI is similar to that of the RF. The purpose of present study was to examine activation of the VI during isometric hip flexion. Ten healthy men performed isometric hip flexion contractions at 25%, 50%, 75%, and 100% of maximal voluntary contraction at hip joint angles of 90°, 110° and 130°. Surface electromyography (EMG was used to record activity of the four quadriceps femoris muscles and EMG signals were root mean square processed and normalized to EMG amplitude during an isometric knee extension with maximal voluntary contraction. The normalized EMG was significantly higher for the VI than for the vastus medialis during hip flexion at 100% of maximal voluntary contraction at hip joint angles of 110° and 130° (P < 0.05. The onset of VI activation was 230-240 ms later than the onset of RF activation during hip flexion at each hip joint angle, which was significantly later than during knee extension at 100% of maximal voluntary contraction (P < 0.05. These results suggest that the VI is activated later than the RF during hip flexion. Activity of the VI during hip flexion might contribute to stabilize the knee joint as an antagonist and might help to smooth knee joint motion, such as in the transition from hip flexion to knee extension during walking, running and pedaling.

Do patients care about higher flexion in total knee arthroplasty?

DEFF Research Database (Denmark)

Thomsen, Morten G; Husted, Henrik; Otte, Kristian Stahl

2013-01-01

BACKGROUND: Little information exists to support that patients care about flexion beyond what is needed to perform activities of daily living (ADL) after Total knee arthroplasty (TKA). The purpose of this study was to investigate if the achievement of a higher degree of knee flexion after TKA would...

[Research progress of larger flexion gap than extension gap in total knee arthroplasty].

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Zhang, Weisong; Hao, Dingjun

2017-05-01

To summarize the progress of larger flexion gap than extension gap in total knee arthro-plasty (TKA). The domestic and foreign related literature about larger flexion gap than extension gap in TKA, and its impact factors, biomechanical and kinematic features, and clinical results were summarized. During TKA, to adjust the relations of flexion gap and extension gap is one of the key factors of successful operation. The biomechanical, kinematic, and clinical researches show that properly larger flexion gap than extension gap can improve both the postoperative knee range of motion and the satisfaction of patients, but does not affect the stability of the knee joint. However, there are also contrary findings. So adjustment of flexion gap and extension gap during TKA is still in dispute. Larger flexion gap than extension gap in TKA is a new joint space theory, and long-term clinical efficacy, operation skills, and related complications still need further study.

Efficient computation of quasiperiodic oscillations in nonlinear systems with fast rotating parts

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Schilder, Frank; Rübel, Jan; Starke, Jens

2008-01-01

We present a numerical method for the investigation of quasiperiodic oscillations in applications modeled by systems of ordinary differential equations. We focus on systems with parts that have a significant rotational speed. An important element of our approach is that it allows us to verify whe...

3D Analysis of the Proximal Interphalangeal Joint Kinematics during Flexion

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Florian Hess

2013-01-01

Full Text Available Background. Dynamic joint motion recording combined with CT-based 3D bone and joint surface data is accepted as a helpful and precise tool to analyse joint. The purpose of this study is to demonstrate the feasibility of these techniques for quantitative motion analysis of the interphalangeal joint in 3D. Materials and Method. High resolution motion data was combined with an accurate 3D model of a cadaveric index finger. Three light-emitting diodes (LEDs were used to record dynamic data, and a CT scan of the finger was done for 3D joint surface geometry. The data allowed performing quantitative evaluations such as finite helical axis (FHA analysis, coordinate system optimization, and measurement of the joint distances in 3D. Results. The FHA varies by 4.9±1.7° on average. On average, the rotation in adduction/abduction and internal/external rotation were 0.3±0.91° and 0.1±0.97°, respectively. During flexion, a translational motion between 0.06 mm and 0.73 mm was observed. Conclusions. The proposed technique and methods appear to be feasible for the accurate assessment and evaluation of the PIP joint motion in 3D. The presented method may help to gain additional insights for the design of prosthetic implants, rehabilitation, and new orthotic devices.

Three-dimensional morphometric analysis of the coracohumeral distance using magnetic resonance imaging

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Taku Hatta

2017-03-01

Full Text Available There have been no studies investigating three-dimensional (3D alteration of the coracohumeral distance (CHD associated with shoulder motion. The aim of this study was to investigate the change of 3D-CHD with the arm in flexion/internal rotation and horizontal adduction. Six intact shoulders of four healthy volunteers were obtained for this study. MRI was taken in four arm positions: with the arm in internal rotation at 0°, 45°, and 90° of flexion, and 90° of flexion with maximum horizontal adduction. Using a motion analysis system, 3D models of the coracoid process and proximal humerus were created from MRI data. The CHD among the four positions were compared, and the closest part of coracoid process to the proximal humerus was also assessed. 3D-CHD significantly decreased with the arm in 90° of flexion and in 90° of flexion with horizontal adduction comparing with that in 0° flexion (P<0.05. In all subjects, lateral part of the coracoid process was the closest to the proximal humerus in these positions. In vivo quasi-static motion analysis revealed that the 3D-CHD was narrower in the arm position of flexion with horizontal abduction than that in 0° flexion. The lateral part on the coracoid process should be considered to be closest to the proximal humerus during the motion.

Repeatability of cervical joint flexion and extension within and between days

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Wang, Xu; Lindstroem, René; Plocharski, Maciej

2018-01-01

OBJECTIVE: The purpose of this study was to investigate within- and between-day repeatability of free and unrestricted healthy cervical flexion and extension motion when assessing dynamic cervical spine motion. METHODS: Fluoroscopy videos of 2 repeated cervical flexion and 2 repeated extension...

Angioleiomyoma: A Rare Cause of Fixed Flexion Contracture of the Elbow

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Asterios Dramis

2006-01-01

Full Text Available We describe an unusual case of a patient presented with a painless fixed flexion contracture of the elbow due to an angioleiomyoma. This benign smooth muscle tumour should be considered in the differential diagnosis of flexion contractures of the elbow.

Direction-specific recruitment of rotator cuff muscles during bench press and row.

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Wattanaprakornkul, Duangjai; Halaki, Mark; Cathers, Ian; Ginn, Karen A

2011-12-01

Recent studies indicate that rotator cuff (RC) muscles are recruited in a reciprocal, direction-specific pattern during shoulder flexion and extension exercises. The main purpose of this study was to determine if similar reciprocal RC recruitment occurs during bench press (flexion-like) and row (extension-like) exercises. In addition, shoulder muscle activity was comprehensively compared between bench press and flexion; row and extension; and bench press and row exercises. Electromyographic (EMG) activity was recorded from 9 shoulder muscles sites in 15 normal volunteers. All exercises were performed at 20, 50 and 70% of subjects' maximal load. EMG data were normalized to standard maximal voluntary contractions. Infraspinatus activity was significantly higher than subscapularis during bench press, with the converse pattern during the row exercise. Significant differences in activity levels were found in pectoralis major, deltoid and trapezius between the bench press and flexion exercises and in lower trapezius between the row and extension exercises. During bench press and row exercises, the recruitment pattern in each active muscle did not vary with load. During bench press and row exercises, RC muscles contract in a reciprocal direction-specific manner in their role as shoulder joint dynamic stabilizers to counterbalance antero-posterior translation forces. Copyright © 2011 Elsevier Ltd. All rights reserved.

MOUNTABILITY PARTS OF MACHINE WITH ROTATING SURFACE, FITTED WITH POSITIVE CLEARANCE

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Zbigniew BUDNIAK

2014-06-01

Full Text Available In this paper demonstrates the conditions of automatic assembly the parts of machines with rotating surfaces, fitted with positive clearance. Determination of the general condition of asseblability allowed for designation of the acceptable relative displacement and torsion axle, combined parts on the mounting position. The designation of depending allowed for assess the technological capacity of the installation equipment. On the basis of this mathematical model was developed a computer program that allows to determine the effect of geometric, strength and dynamic parameters of the assembly process. The examples of results of numerical calculations are shown in the graphs

Gender differences in passive knee biomechanical properties in tibial rotation.

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Park, Hyung-Soon; Wilson, Nicole A; Zhang, Li-Qun

2008-07-01

The anterior cruciate ligament (ACL) is the most commonly injured knee ligament with the highest incidence of injury in female athletes who participate in pivoting sports. Noncontact ACL injuries commonly occur with both internal and external tibial rotation. ACL impingement against the lateral wall of the intercondylar notch during tibial external rotation and abduction has been proposed as an injury mechanism, but few studies have evaluated in vivo gender-specific differences in laxity and stiffness in external and internal tibial rotations. The purpose of this study was to evaluate these differences. The knees of 10 male and 10 female healthy subjects were rotated between internal and external tibial rotation with the knee at 60 degrees of flexion. Joint laxity, stiffness, and energy loss were compared between male and female subjects. Women had higher laxity (p = 0.01), lower stiffness (p = 0.038), and higher energy loss (p = 0.008) in external tibial rotation than did men. The results suggest that women may be at greater risk of ACL injury resulting from impingement against the lateral wall of the intercondylar notch, which has been shown to be associated with external tibial rotation and abduction.

The effect of hip position upon the location of the sciatic nerve: an MRI Study.

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Birke, Oliver; Mitchell, Piers D; Onikul, Ella; Little, David G

2011-03-01

Allowance for the positional changes of the sciatic nerve is important when considering the safest position of the leg to perform hip operations, specifically the ischial osteotomy during a pelvic triple or periacetabular osteotomy. As for its proximity to the osteotomy site the sciatic nerve can be injured during these operations with the consequence of severe functional impairment. This is the first in-vivo study that demonstrates the effect of hip position upon the location of the sciatic nerve. We determined how altering the position of the hip moves the nerve toward or away from the infracotyloid groove, the desired starting point of the ischial osteotomy site just inferior to the acetabulum when performing a pelvic triple or periacetabular osteotomy. Magnetic resonance imaging scans of the left hip in 3 different positions (neutral/supine, 30 to 45 degrees flexion, 30 to 45 degrees flexion/abduction/external rotation) were performed in 11 healthy children (5 boys and 6 girls, age 7 to 17 y) without prior hip surgery. The distance between the sciatic nerve and the infracotyloid groove was measured on the magnetic resonance images. Distance ratios based on the neutral position were calculated for flexion and flexion/abduction/external rotation for each of the participants. The sciatic nerve moves toward the ischium osteotomy site in hip flexion without abduction (mean flexion: neutral ratio 0.79, Pexternally rotated (mean flexion/abduction/external rotation: neutral ratio 1.34), meaning the distance from nerve to infracotyloid groove increases significantly (Pmean distances were 14.8 mm (11 to 20 mm) in neutral, 11.8 mm (9 to 16 mm) in flexion, and 20.0 mm (9 to 30 mm) in flexion/abduction/external rotation. The likely safest position of the hip/leg to perform the ischium osteotomy as part of a pelvic triple or periacetabular osteotomy is in flexion, abduction, and external rotation. In this position the osteotomy can be performed via a medial or anterior

Experimental measurement of flexion-extension movement in normal and corpse prosthetic elbow joint.

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TarniŢă, Daniela; TarniŢă, DănuŢ Nicolae

2016-01-01

This paper presents a comparative experimental study of flexion-extension movement in healthy elbow and in the prosthetic elbow joint fixed on an original experimental bench. Measurements were carried out in order to validate the functional morphology and a new elbow prosthesis type ball head. The three-dimensional (3D) model and the physical prototype of our experimental bench used to test elbow endoprosthesis at flexion-extension and pronation-supination movements is presented. The measurements were carried out on a group of nine healthy subjects and on the prosthetic corpse elbow, the experimental data being obtained for flexion-extension movement cycles. Experimental data for the two different flexion-extension tests for the nine subjects and for the corpse prosthetic elbow were acquired using SimiMotion video system. Experimental data were processed statistically. The corresponding graphs were obtained for all subjects in the experimental group, and for corpse prosthetic elbow for both flexion-extension tests. The statistical analysis has proved that the flexion angles of healthy elbows were significantly close to the values measured at the prosthetic elbow fixed on the experimental bench. The studied elbow prosthesis manages to re-establish the mobility for the elbow joint as close to the normal one.

Isokinetic profile of elbow flexion and extension strength in elite junior tennis players.

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Ellenbecker, Todd S; Roetert, E Paul

2003-02-01

Descriptive study. To determine whether bilateral differences exist in concentric elbow flexion and extension strength in elite junior tennis players. The repetitive nature of tennis frequently produces upper extremity overuse injuries. Prior research has identified tennis-specific strength adaptation in the dominant shoulder and distal upper extremity musculature of elite players. No previous study has addressed elbow flexion and extension strength. Thirty-eight elite junior tennis players were bilaterally tested for concentric elbow flexion and extension muscle performance on a Cybex 6000 isokinetic dynamometer at 90 degrees/s, 210 degrees/s, and 300 degrees/s. Repeated-measures ANOVAs were used to test for differences between extremities, muscle groups, and speed. Significantly greater (Pelbow extension peak torque values were measured at 90 degrees/s, 210 degrees/s, and 300 degrees/s for males. Significantly greater (Pelbow flexion muscular performance in males and for elbow flexion or extension peak torque and single-repetition work values in females. No significant difference between extremities was measured in elbow flexion/extension strength ratios in females and significant differences between extremities in this ratio were only present at 210 degrees/s in males (Pelbow in male elite junior tennis players but not females. These data have ramifications for clinicians rehabilitating upper extremity injuries in patients from this population.

[A new kinematics method of determing elbow rotation axis and evaluation of its feasibility].

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Han, W; Song, J; Wang, G Z; Ding, H; Li, G S; Gong, M Q; Jiang, X Y; Wang, M Y

2016-04-18

To study a new positioning method of elbow external fixation rotation axis, and to evaluate its feasibility. Four normal adult volunteers and six Sawbone elbow models were brought into this experiment. The kinematic data of five elbow flexion were collected respectively by optical positioning system. The rotation axes of the elbow joints were fitted by the least square method. The kinematic data and fitting results were visually displayed. According to the fitting results, the average moving planes and rotation axes were calculated. Thus, the rotation axes of new kinematic methods were obtained. By using standard clinical methods, the entrance and exit points of rotation axes of six Sawbone elbow models were located under X-ray. And The kirschner wires were placed as the representatives of rotation axes using traditional positioning methods. Then, the entrance point deviation, the exit point deviation and the angle deviation of two kinds of located rotation axes were compared. As to the four volunteers, the indicators represented circular degree and coplanarity of elbow flexion movement trajectory of each volunteer were both about 1 mm. All the distance deviations of the moving axes to the average moving rotation axes of the five volunteers were less than 3 mm. All the angle deviations of the moving axes to the average moving rotation axes of the five volunteers were less than 5°. As to the six Sawbone models, the average entrance point deviations, the average exit point deviations and the average angle deviations of two different rotation axes determined by two kinds of located methods were respectively 1.697 2 mm, 1.838 3 mm and 1.321 7°. All the deviations were very small. They were all in an acceptable range of clinical practice. The values that represent circular degree and coplanarity of volunteer's elbow single curvature movement trajectory are very small. The result shows that the elbow single curvature movement can be regarded as the approximate fixed

Rotating gravity currents. Part 1. Energy loss theory

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Martin, J. R.; Lane-Serff, G. F.

2005-01-01

A comprehensive energy loss theory for gravity currents in rotating rectangular channels is presented. The model is an extension of the non-rotating energy loss theory of Benjamin (J. Fluid Mech. vol. 31, 1968, p. 209) and the steady-state dissipationless theory of rotating gravity currents of Hacker (PhD thesis, 1996). The theory assumes the fluid is inviscid, there is no shear within the current, and the Boussinesq approximation is made. Dissipation is introduced using a simple method. A head loss term is introduced into the Bernoulli equation and it is assumed that the energy loss is uniform across the stream. Conservation of momentum, volume flux and potential vorticity between upstream and downstream locations is then considered. By allowing for energy dissipation, results are obtained for channels of arbitrary depth and width (relative to the current). The results match those from earlier workers in the two limits of (i) zero rotation (but including dissipation) and (ii) zero dissipation (but including rotation). Three types of flow are identified as the effect of rotation increases, characterized in terms of the location of the outcropping interface between the gravity current and the ambient fluid on the channel boundaries. The parameters for transitions between these cases are quantified, as is the detailed behaviour of the flow in all cases. In particular, the speed of the current can be predicted for any given channel depth and width. As the channel depth increases, the predicted Froude number tends to surd 2, as for non-rotating flows.

ARTHROMETRIC EVALUATION OF STABILIZING EFFECT OF KNEE FUNCTIONAL BRACING AT DIFFERENT FLEXION ANGLES

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Saeedeh Seyed Mohseni

2009-06-01

Full Text Available Previous in-vivo investigations on the stabilizing efficacy of knee bracing for ACL reconstructed patients have been often limited to 20-30 degrees of knee flexion. In this study, the effectiveness of a uniaxial hinged functional brace to improve the knee stability was assessed at 30, 60 and 90 degrees of knee flexion. Arthrometry tests were conducted on 15 healthy subjects before and following wearing the brace and the tibial displacements were measured at up to 150 N anterior forces. Results indicated that functional bracing has a significant stabilizing effect throughout the range of knee flexion examined (p < 0.05. The rate of effectiveness, however, was not consistent across the flexion range, e.g., 50% at 30 degrees and only 4% at 90 degrees. It was suggested that accurate sizing and fitting as well as attention to correct hinge placement relative to the femoral condyles can limit brace migration and improve its effectiveness in mid and deep knee flexion. With using adaptive limb fittings, through flexible pads, and a polycentric joint a more significant improvement of the overall brace performance and efficacy might be obtained

Extension and flexion in the upper cervical spine in neck pain patients.

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Ernst, Markus J; Crawford, Rebecca J; Schelldorfer, Sarah; Rausch-Osthoff, Anne-Kathrin; Barbero, Marco; Kool, Jan; Bauer, Christoph M

2015-08-01

Neck pain is a common problem in the general population with high risk of ongoing complaints or relapses. Range of motion (ROM) assessment is scientifically established in the clinical process of diagnosis, prognosis and outcome evaluation in neck pain. Anatomically, the cervical spine (CS) has been considered in two regions, the upper and lower CS. Disorders like cervicogenic headache have been clinically associated with dysfunctions of the upper CS (UCS), yet ROM tests and measurements are typically conducted on the whole CS. A cross-sectional study assessing 19 subjects with non-specific neck pain was undertaken to examine UCS extension-flexion ROM in relation to self-reported disability and pain (via the Neck Disability Index (NDI)). Two measurement devices (goniometer and electromagnetic tracking) were employed and compared. Correlations between ROM and the NDI were stronger for the UCS compared to the CS, with the strongest correlation between UCS flexion and the NDI-headache (r = -0.62). Correlations between UCS and CS ROM were fair to moderate, with the strongest correlation between UCS flexion and CS extension ROM (r = -0.49). UCS flexion restriction is related to headache frequency and intensity. Consistency and agreement between both measurement systems and for all tests was high. The results demonstrate that separate UCS ROM assessments for extension and flexion are useful in patients with neck pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pneumatic-type dynamic traction and flexion splint for treating patients with extension contracture of the metacarpophalangeal joint.

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Nakayama, Jun; Horiki, Mituru; Denno, Kakurou; Ogawa, Kazunori; Oka, Hisao; Domen, Kazuhisa

2016-02-01

Collateral ligament shortening causes extension contractures of the metacarpophalangeal joint, and dynamic flexion splinting has been widely used to treat these contractures; however, there are various problems with these approaches. We developed a novel, pneumatic-type dynamic traction and flexion splint to solve these problems. A total of 25 fingers were treated with the dynamic traction and flexion splint for 8 weeks. Every 2 weeks, the average metacarpophalangeal joint flexion angle, total active motion, grasp strength, and pain scores were assessed. The finger flexion angle was significantly greater at the final evaluation, starting after 6 weeks of treatment (p < 0.05), than prior to treatment. Similarly, the total active motion results improved significantly over 8 weeks. Our results show that use of the dynamic traction and flexion splint improves patient finger functioning and flexural angle. The dynamic traction and flexion (DTF) splint appears to be effective for treating patients. © The International Society for Prosthetics and Orthotics 2015.

Reverse arthroplasty for osteoarthritis and rotator cuff deficiency after previous surgery for recurrent anterior shoulder instability.

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Raiss, Patric; Zeifang, Felix; Pons-Villanueva, Juan; Smithers, Christopher J; Loew, Markus; Walch, Gilles

2014-07-01

Osteoarthritis in combination with rotator cuff deficiency following previous shoulder stabilisation surgery and after failed surgical treatment for chronic anterior shoulder dislocation is a challenging condition. The aim of this study was to analyse the results of reverse shoulder arthroplasty in such patients. Thirteen patients with a median follow-up of 3.5 (range two to eight) years and a median age of 70 (range 48-82) years were included. In all shoulders a tear of at least one rotator cuff tendon in combination with osteoarthritis was present at the time of arthroplasty. The Constant score, shoulder flexion and external and internal rotation with the elbow at the side were documented pre-operatively and at the final follow-up. Pre-operative, immediate post-operative and final follow-up radiographs were analysed. All complications and revisions were documented. Twelve patients were either satisfied or very satisfied with the procedure. The median Constant score increased from 26 points pre-operatively to 67 points at the final follow-up (p = 0.001). The median shoulder flexion increased significantly from 70° to 130° and internal rotation from two to four points (p = 0.002). External rotation did not change significantly (p = 0.55). Glenoid notching was present in five cases and was graded as mild in three cases and moderate in two. One complication occurred leading to revision surgery. Reverse arthroplasty leads to high satisfaction rates for patients with osteoarthritis and rotator cuff deficiency who had undergone previous shoulder stabilisation procedures. The improvements in clinical outcome as well as the radiographic results seem to be comparable with those of other studies reporting on the outcome of reverse shoulder arthroplasty for other conditions.

The effect of posterior tibial slope on knee flexion in posterior-stabilized total knee arthroplasty.

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Shi, Xiaojun; Shen, Bin; Kang, Pengde; Yang, Jing; Zhou, Zongke; Pei, Fuxing

2013-12-01

To evaluate and quantify the effect of the tibial slope on the postoperative maximal knee flexion and stability in the posterior-stabilized total knee arthroplasty (TKA). Fifty-six patients (65 knees) who had undergone TKA with the posterior-stabilized prostheses were divided into the following 3 groups according to the measured tibial slopes: Group 1: ≤4°, Group 2: 4°-7° and Group 3: >7°. The preoperative range of the motion, the change in the posterior condylar offset, the elevation of the joint line, the postoperative tibiofemoral angle and the preoperative and postoperative Hospital for Special Surgery (HSS) scores were recorded. The tibial anteroposterior translation was measured using the Kneelax 3 Arthrometer at both the 30° and the 90° flexion angles. The mean values of the postoperative maximal knee flexion were 101° (SD 5), 106° (SD 5) and 113° (SD 9) in Groups 1, 2 and 3, respectively. A significant difference was found in the postoperative maximal flexion between the 3 groups (P slope resulted in a 1.8° flexion increment (r = 1.8, R (2) = 0.463, P slope can significantly increase the postoperative maximal knee flexion. The tibial slope with an appropriate flexion and extension gap balance during the operation does not affect the joint stability.

The range of excursion of flexor tendons in Zone V: a comparison of active vs passive flexion mobilisation regimes.

LENUS (Irish Health Repository)

Panchal, J

1997-10-01

A number of early postoperative mobilisation regimes have been developed in an attempt to increase tendon excursion and gliding and thereby reduce formation of adhesions following repair of flexor tendons. Early active flexion mobilisation regimes are becoming more popular, and have replaced early passive flexion regimes in many centres. The aim of the present study was: (a) to determine the range of excursion of flexor tendons in Zone V, and (b) to compare the excursion ranges between active (Belfast) and passive (modified Duran) flexion mobilisation regimes postoperatively. This was done (a) in two cadavers, and (b) in two patients intraoperatively, and postoperatively at 10 days, 3 weeks and 6 weeks. With passive flexion, the mean tendon excursion in Zone V in cadavers was 1 mm for flexor digitorum superficialis (FDS), flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) tendons respectively. With simulated active flexion, the mean tendon excursion was 14 mm, 10 mm and 11 mm respectively. The mean tendon excursion in clinical cases intraoperatively following passive flexion was 2 mm for FDS, FDP and FPL respectively; following simulated active flexion it was 10 mm, 11 mm and 11 mm for FDS, FDP and FPL respectively. On the tenth day following repair, the mean excursions of FDS, FDP and FPL were 1 mm, 4 mm and 4 mm on passive flexion as compared to 3 mm, 10 mm and 12 mm on active flexion respectively. Three weeks postoperatively, the mean excursions of FDS, FDP and FPL tendons were 1 mm, 2 mm and 1 mm on passive flexion as compared to 5 mm, 15 mm on active flexion respectively. Six weeks postoperatively, the mean excursions of FDS, FDP and FPL tendons were 9 mm, 7 mm and 4 mm on passive flexion as compared to 12 mm, 33 mm and 20 mm on active flexion respectively. These results demonstrate an increased excursion of repaired flexor tendons in Zone V following an active flexion mobilisation regime as compared to a passive flexion mobilisation regime.

Comparative study of phrenic and intercostal nerve transfers for elbow flexion after global brachial plexus injury.

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Liu, Yuzhou; Lao, Jie; Zhao, Xin

2015-04-01

Global brachial plexus injuries (BPIs) are devastating events frequently resulting in severe functional impairment. The widely used nerve transfer sources for elbow flexion in patients with global BPIs include intercostal and phrenic nerves. The aim of this study was to compare phrenic and intercostal nerve transfers for elbow flexion after global BPI. A retrospective review of 33 patients treated with phrenic and intercostal nerve transfer for elbow flexion in posttraumatic global root avulsion BPI was carried out. In the phrenic nerve transfer group, the phrenic nerve was transferred to the anterolateral bundle of the anterior division of the upper trunk (23 patients); in the intercostal nerve transfer group, three intercostal nerves were coapted to the anterolateral bundles of the musculocutaneous nerve. The British Medical Research Council (MRC) grading system, angle of elbow flexion, and electromyography (EMG) were used to evaluate the recovery of elbow flexion at least 3 years postoperatively. The efficiency of motor function in the phrenic nerve transfer group was 83%, while it was 70% in the intercostal nerve transfer group. The two groups were not statistically different in terms of the MRC grade (p=0.646) and EMG results (p=0.646). The outstanding rates of angle of elbow flexion were 48% and 40% in the phrenic and intercostal nerve transfer groups, respectively. There was no significant difference of outstanding rates in the angle of elbow flexion between the two groups. Phrenic nerve transfer had a higher proportion of good prognosis for elbow flexion than intercostal nerve transfer, but the effective and outstanding rate had no significant difference for biceps reinnervation between the two groups according to MRC grading, angle of elbow flexion, and EMG. Copyright © 2014 Elsevier Ltd. All rights reserved.

Load and speed effects on the cervical flexion relaxation phenomenon

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Descarreaux Martin

2010-03-01

Full Text Available Abstract Background The flexion relaxation phenomenon (FRP represents a well-studied neuromuscular response that occurs in the lumbar and cervical spine. However, the cervical spine FRP has not been investigated extensively, and the speed of movement and loading effects remains to be characterized. The objectives of the present study were to evaluate the influence of load and speed on cervical FRP electromyographic (EMG and kinematic parameters and to assess the measurement of cervical FRP kinematic and EMG parameter repeatability. Methods Eighteen healthy adults (6 women and 12 men, aged 20 to 39 years, participated in this study. They undertook 2 sessions in which they had to perform a standardized cervical flexion/extension movement in 3 phases: complete cervical flexion; the static period in complete cervical flexion; and extension with return to the initial position. Two different rhythm conditions and 3 different loading conditions were applied to assess load and speed effects. Kinematic and EMG data were collected, and dependent variables included angles corresponding to the onset and cessation of myoelectric silence as well as the root mean square (RMS values of EMG signals. Repeatability was examined in the first session and between the 2 sessions. Results Statistical analyses revealed a significant load effect (P Conclusions The load increase evoked augmented FRP onset and cessation angles as well as heightened muscle activation. Such increments may reflect the need to enhance spinal stability under loading conditions. The kinematic and EMG parameters showed promising repeatability. Further studies are needed to assess kinematic and EMG differences between healthy subjects and patients with neck pain.

Lumbopelvic flexibility modulates neuromuscular responses during trunk flexion-extension.

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Sánchez-Zuriaga, Daniel; Artacho-Pérez, Carla; Biviá-Roig, Gemma

2016-06-01

Various stimuli such as the flexibility of lumbopelvic structures influence the neuromuscular responses of the trunk musculature, leading to different load sharing strategies and reflex muscle responses from the afferents of lumbopelvic mechanoreceptors. This link between flexibility and neuromuscular response has been poorly studied. The aim of this study was to investigate the relationship between lumbopelvic flexibility and neuromuscular responses of the erector spinae, hamstring and abdominal muscles during trunk flexion-extension. Lumbopelvic movement patterns were measured in 29 healthy women, who were separated into two groups according to their flexibility during trunk flexion-extension. The electromyographic responses of erector spinae, rectus abdominis and biceps femoris were also recorded. Subjects with greater lumbar flexibility had significantly less pelvic flexibility and vice versa. Subjects with greater pelvic flexibility had a higher rate of relaxation and lower levels of hamstring activation during maximal trunk flexion. The neuromuscular response patterns of the hamstrings seem partially modulated by pelvic flexibility. Not so with the lumbar erector spinae and lumbar flexibility, despite the assertions of some previous studies. The results of this study improve our knowledge of the relationships between trunk joint flexibility and neuromuscular responses, a relationship which may play a role in low back pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biceps brachii long head overactivity associated with elbow flexion contracture in brachial plexus birth palsy.

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Sheffler, Lindsey C; Lattanza, Lisa; Sison-Williamson, Mitell; James, Michelle A

2012-02-15

The etiology of elbow flexion contracture in children with brachial plexus birth palsy remains unclear. We hypothesized that the long head of the biceps brachii muscle assists with shoulder stabilization in children with brachial plexus birth palsy and that overactivity of the long head during elbow and shoulder activity is associated with an elbow flexion contracture. Twenty-one patients with brachial plexus birth palsy-associated elbow flexion contracture underwent testing with surface electromyography. Twelve patients underwent repeat testing with fine-wire electromyography. Surface electrodes were placed on the muscle belly, and fine-wire electrodes were inserted bilaterally into the long and short heads of the biceps brachii. Patients were asked to perform four upper extremity tasks: elbow flexion-extension, hand to head, high reach, and overhead ball throw. The mean duration of muscle activity in the affected limb was compared with that in the contralateral, unaffected limb, which was used as a control. Three-dimensional motion analysis, surface dynamometry, and validated function measures were used to evaluate upper extremity kinematics, elbow flexor-extensor muscle imbalance, and function. The mean activity duration of the long head of the biceps brachii muscle was significantly higher in the affected limb as compared with the contralateral, unaffected limb during hand-to-head tasks (p = 0.02) and high-reach tasks (p = 0.03). No significant differences in mean activity duration were observed for the short head of the biceps brachii muscle between the affected and unaffected limbs. Isometric strength of elbow flexion was not significantly higher than that of elbow extension in the affected limb (p = 0.11). Overactivity of the long head of the biceps brachii muscle is associated with and may contribute to the development of elbow flexion contracture in children with brachial plexus birth palsy. Elbow flexion contracture may not be associated with an elbow

Decoding Finger Flexion From Band-specific ECoG Signals in Humans

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Nanying eLiang

2012-06-01

Full Text Available This article presents the method that won the BCI competition IV addressed to the pre- diction of the finger flexion from ECoG signals. ECoG-based BCIs have recently drawn the attention from the community. Indeed, ECoG can provide a higher spatial resolution, a higher signal quality and is more suitable for long-term use than classical EEG recordings. These characteristics allow to decode precise brain activities and to realize efficient ECoG-based neu- roprostheses. Signal processing is a very important task in BCIs research for translating brain signals into commands. Here, we present a linear regression method based on the amplitude modulation of band-specific ECoG including a short term memory for individual finger flexion prediction. The effectiveness of the method was proven by achieving the highest value of corre- lation coefficient between the predicted and recorded finger flexion values on data set 4 during the BCI competition IV.

Pelvic rotation torque during fast-pitch softball hitting under three ball height conditions.

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Iino, Yoichi; Fukushima, Atsushi; Kojima, Takeji

2014-08-01

The purpose of this study was to investigate the relevance of hip joint angles to the production of the pelvic rotation torque in fast-pitch softball hitting and to examine the effect of ball height on this production. Thirteen advanced female softball players hit stationary balls at three different heights: high, middle, and low. The pelvic rotation torque, defined as the torque acting on the pelvis through the hip joints about the pelvic superior-inferior axis, was determined from the kinematic and force plate data using inverse dynamics. Irrespective of the ball heights, the rear hip extension, rear hip external rotation, front hip adduction, and front hip flexion torques contributed to the production of pelvic rotation torque. Although the contributions of the adduction and external rotation torques at each hip joint were significantly different among the ball heights, the contributions of the front and rear hip joint torques were similar among the three ball heights owing to cancelation of the two torque components. The timings of the peaks of the hip joint torque components were significantly different, suggesting that softball hitters may need to adjust the timings of the torque exertions fairly precisely to rotate the upper body effectively.

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

A Textile-Based Wearable Sensing Device Designed for Monitoring the Flexion Angle of Elbow and Knee Movements

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Tien-Wei Shyr

2014-02-01

Full Text Available In this work a wearable gesture sensing device consisting of a textile strain sensor, using elastic conductive webbing, was designed for monitoring the flexion angle of elbow and knee movements. The elastic conductive webbing shows a linear response of resistance to the flexion angle. The wearable gesture sensing device was calibrated and then the flexion angle-resistance equation was established using an assembled gesture sensing apparatus with a variable resistor and a protractor. The proposed device successfully monitored the flexion angle during elbow and knee movements.

Experimental occlusal interferences. Part V. Mandibular rotations versus hemimandibular translations.

Science.gov (United States)

Christensen, L V; Rassouli, N M

1995-12-01

Frontal plane mandibular rotations and corresponding hemimandibular translations were studied in vitro by using direct observations of a human cadaver mandible and in vivo by using the indirect observations of rotational electrognathography. A comparison between the two methods showed that rotational electrognathography erred in measuring the clinically relevant hemimandibular translations resulting from mandibular rotations having a unilateral molar point (simulated occlusal interference) as the pivot of frontal plane torque. In vitro frontal plane rotations about a unilateral mandibular molar tooth (simulated occlusal interference) suggested that the resulting hemimandibular upward translations of the lateral portion of the mandibular condyle, contralateral to the molar tooth, would cause considerable compressive loading of the temporomandibular joint disc.

Arthroscopic evaluation of patellofemoral congruence with rotation of the knee joint and electrical stimulation of the quadriceps.

Science.gov (United States)

Suganuma, Jun; Mochizuki, Ryuta; Inoue, Yutaka; Kitamura, Kazuya; Honda, Akio

2014-02-01

The aim of this study was to investigate the pathoanatomic features of patellar instability by arthroscopically comparing patellofemoral congruence with rotation of the knee joint and/or electrical stimulation of the quadriceps (ESQ) between knees with and without patellar instability. We retrospectively examined 83 knee joints in 83 patients. The joints were classified into 2 groups: group 1 comprised those without a history of patellar dislocation and included 59 patients (25 male and 34 female patients), and group 2 comprised those with a history of patellar dislocation and included 24 patients (9 male and 15 female patients). Evaluation of patellofemoral congruence at 30° of flexion of the knee joint was conducted based on an axial radiograph and arthroscopic findings. The congruence angle was measured on the radiograph. The position of the patellar central ridge (PPCR) on the trochlear groove during arthroscopy was measured using still video frames of knee joints with rotational stress and/or ESQ. Statistical differences in the measurements between the 2 groups were assessed with the unpaired t test and the area under the receiver operating characteristic curve of each measurement. There were significant differences (P congruence angle on radiographs and PPCR in knee joints with rotational stress and/or ESQ on arthroscopy. External and internal rotation of the knee joint caused lateral and medial patellar shift, respectively, in both groups, but the shift was significantly larger in group 2. ESQ in addition to rotation caused further patellar shift in group 2 but reduced patellar shift in group 1. Measurement of PPCR with external rotation of the knee and ESQ was the only method to show an area under the receiver operating characteristic curve of 1. There were significant differences in the effects of rotation of the knee joint and/or ESQ on patellofemoral congruence at 30° of flexion of the knee joint on arthroscopy between knees with and without patellar

Isolated flexor pollicis longus nerve fascicle lesion – a rare differential diagnosis of thumb flexion deficiency

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Glauser, Eva

2016-12-01

Full Text Available A rare differential diagnosis of thumb flexion deficiency is an isolated flexor pollicis longus (FPL nerve fascicle lesion. We present a 42-year-old otherwise healthy female patient who developed a weak thumb-to-index pinch and deficient right thumb flexion following the removal of osteosynthesis plates after a forearm fracture. Clinically,the flexor pollicis longus function was absent, yet index flexion and sensibility were unimpaired. Tendon rupture was excluded using a tenodesis test and the electro-physiological result of isolated interosseus nerve fascicle lesion was confirmed intraoperatively by inspection and electrostimulation. Tendon transfer using the extensor carpi radialis longus reconstruct strong thumb flexion during pinch. In summary, due to its specific location and anatomy, the FPL branch is more prone to isolated neuropathy, e.g. by injections or operations, than to other fascicles of the anterior interosseus nerve. When confronted with sudden and isolated thumb flexion deficiency, specialists should be aware of this rare phenomenon.

The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve

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Baiget Ernest

2016-12-01

Full Text Available The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation. Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p < 0.05. Low to moderate correlations were also found between serve velocity and wrist, elbow and shoulder flexion – extension, leg and back extension and shoulder external rotation (r = 0.36 – 0.53; p = 0.377 – 0.054. Bivariate and multivariate models for predicting serve velocity were developed, with shoulder flexion and internal rotation explaining 55% of the variance in serve velocity (r = 0.74; p < 0.001. The maximum isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

MRI-based analysis of patellofemoral cartilage contact, thickness, and alignment in extension, and during moderate and deep flexion.

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Freedman, Benjamin R; Sheehan, Frances T; Lerner, Amy L

2015-10-01

Several factors are believed to contribute to patellofemoral joint function throughout knee flexion including patellofemoral (PF) kinematics, contact, and bone morphology. However, data evaluating the PF joint in this highly flexed state have been limited. Therefore, the purpose of this study was to evaluate patellofemoral contact and alignment in low (0°), moderate (60°), and deep (140°) knee flexion, and then correlate these parameters to each other, as well as to femoral morphology. Sagittal magnetic resonance images were acquired on 14 healthy female adult knees (RSRB approved) using a 1.5 T scanner with the knee in full extension, mid-flexion, and deep flexion. The patellofemoral cartilage contact area, lateral contact displacement (LCD), cartilage thickness, and lateral patellar displacement (LPD) throughout flexion were defined. Intra- and inter-rater repeatability measures were determined. Correlations between patellofemoral contact parameters, alignment, and sulcus morphology were calculated. Measurement repeatability ICCs ranged from 0.94 to 0.99. Patellofemoral cartilage contact area and thickness, LCD, and LPD were statistically different throughout all levels of flexion (ppatellofemoral joint throughout its range of motion. This study agrees with past studies that investigated patellofemoral measures at a single flexion angle, and provides new insights into the relationship between patellofemoral contact and alignment at multiple flexion angles. The study provides a detailed analysis of the patellofemoral joint in vivo, and demonstrates the feasibility of using standard clinical magnetic resonance imaging scanners to image the knee joint in deep flexion. Copyright © 2015 Elsevier B.V. All rights reserved.

Modelling and Analysis on Biomechanical Dynamic Characteristics of Knee Flexion Movement under Squatting

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Jianping Wang

2014-01-01

Full Text Available The model of three-dimensional (3D geometric knee was built, which included femoral-tibial, patellofemoral articulations and the bone and soft tissues. Dynamic finite element (FE model of knee was developed to simulate both the kinematics and the internal stresses during knee flexion. The biomechanical experimental system of knee was built to simulate knee squatting using cadaver knees. The flexion motion and dynamic contact characteristics of knee were analyzed, and verified by comparing with the data from in vitro experiment. The results showed that the established dynamic FE models of knee are capable of predicting kinematics and the contact stresses during flexion, and could be an efficient tool for the analysis of total knee replacement (TKR and knee prosthesis design.

The interference effects of non-rotated versus counter-rotated trials in visuomotor adaptation.

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Hinder, Mark R; Walk, Laura; Woolley, Daniel G; Riek, Stephan; Carson, Richard G

2007-07-01

An isometric torque-production task was used to investigate interference and retention in adaptation to multiple visuomotor environments. Subjects produced isometric flexion-extension and pronation-supination elbow torques to move a cursor to acquire targets as quickly as possible. Adaptation to a 30 degrees counter-clockwise (CCW) rotation (task A), was followed by a period of rest (control), trials with no rotation (task B0), or trials with a 60 degrees clockwise (CW) rotation (task B60). For all groups, retention of task A was assessed 5 h later. With initial training, all groups reduced the angular deviation of cursor paths early in the movements, indicating feedforward adaptation. For the control group, performance at commencement of the retest was significantly better than that at the beginning of the initial learning. For the B0 group, performance in the retest of task A was not dissimilar to that at the start of the initial learning, while for the B60 group retest performance in task A was markedly worse than initially observed. Our results indicate that close juxtaposition of two visuomotor environments precludes improved retest performance in the initial environment. Data for the B60 group, specifically larger angular errors upon retest compared with initial exposures, are consistent with the presence of anterograde interference. Furthermore, full interference occurred even when the visuomotor environment encountered in the second task was not rotated (B0). This latter novel result differs from those obtained for force field learning, where interference does not occur when task B does not impose perturbing forces, i.e., when B consists of a null field (Brashers-Krug et al., Nature 382:252-255, 1996). The results are consistent with recent proposals suggesting different interference mechanisms for visuomotor (kinematic) compared to force field (dynamic) adaptations, and have implications for the use of washout trials when studying interference between

Comparison of the Hamstring Muscle Activity and Flexion-Relaxation Ratio between Asymptomatic Persons and Computer Work-related Low Back Pain Sufferers.

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Kim, Min-Hee; Yoo, Won-Gyu

2013-05-01

[Purpose] The purpose of this study was to compare the hamstring muscle (HAM) activities and flexion-relaxation ratios of an asymptomatic group and a computer work-related low back pain (LBP) group. [Subjects] For this study, we recruited 10 asymptomatic computer workers and 10 computer workers with work-related LBP. [Methods] We measured the RMS activity of each phase (flexion, full-flexion, and re-extension phase) of trunk flexion and calculated the flexion-relaxation (FR) ratio of the muscle activities of the flexion and full-flexion phases. [Results] In the computer work-related LBP group, the HAM muscle activity increased during the full-flexion phase compared to the asymptomatic group, and the FR ration was also significantly higher. [Conclusion] We thought that prolonged sitting of computer workers might cause the change in their HAM muscle activity pattern.

MR imaging of the knee extension and flexion. Diagnostic value for reconstructed anterior cruciate ligament

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Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine] [and others

1995-09-01

The purpose of this study is to determine the value of extended and flexed knee positions in MR imaging of the surgically reconstructed anterior cruciate ligament (ACL). With a mobile knee brace and a flexible surface coil, knee joint was enabled to extend to a full-extension and bend vertically to a semi-flexion (average 45deg of flexion) within the confines of the magnet bore. Sets of 3-mm-thick oblique sagittal proton-weighted turbo spin echo MR images were obtained at both extended and flexed positions. Twenty-five knees with intact ACL grafts and three knees with arthroscopically proved graft tears were evaluated. Compared to the extended position, MR images of flexed knee provided better delineation of the intact and complicated ACL grafts with statistical significance. The intact graft appeared relaxed at the semi-flexion and taut at the extension. Overall lengths of the intact grafts were readily identified at the flexion. Stretched along the intercondylar roof, the grafts were poorly outlined at the extension. MR images with knee flexion delineated the disrupted site from the impingement more clearly than that with knee extension. (author).

Earth Rotation

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Dickey, Jean O.

1995-01-01

The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

Flexion-relaxation ratio in computer workers with and without chronic neck pain.

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Pinheiro, Carina Ferreira; dos Santos, Marina Foresti; Chaves, Thais Cristina

2016-02-01

This study evaluated the flexion-relaxation phenomenon (FRP) and flexion-relaxation ratios (FR-ratios) using surface electromyography (sEMG) of the cervical extensor muscles of computer workers with and without chronic neck pain, as well as of healthy subjects who were not computer users. This study comprised 60 subjects 20-45years of age, of which 20 were computer workers with chronic neck pain (CPG), 20 were computer workers without neck pain (NPG), and 20 were control individuals who do not use computers for work and use them less than 4h/day for other purposes (CG). FRP and FR-ratios were analyzed using sEMG of the cervical extensors. Analysis of FR-ratios showed smaller values in the semispinalis capitis muscles of the two groups of workers compared to the control group. The reference FR-ratio (flexion relaxation ratio [FRR], defined as the maximum activity in 1s of the re-extension/full flexion sEMG activity) was significantly higher in the computer workers with neck pain compared to the CG (CPG: 3.10, 95% confidence interval [CI95%] 2.50-3.70; NPG: 2.33, CI95% 1.93-2.74; CG: 1.99, CI95% 1.81-2.17; pneck pain, and such results suggested that each FR-ratio could have a different application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of hyperpronation and supination‑flexion techniques in ...

African Journals Online (AJOL)

2013-07-24

Jul 24, 2013 ... Green DA, Linares YM, Garcia Pena MB, Greenberg M, Baker RL: Randomized comparison of pain perception during radial head subluxation using supination‑ flexion or forced pronation. Pediatr Emerg Care 2006;22:235‑8. 8. McDonald LJ, Whitelaw C, Goldsmith L. Radial head subluxation: Comparing.

The effect of prior lumbar surgeries on the flexion relaxation phenomenon and its responsiveness to rehabilitative treatment.

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Neblett, Randy; Mayer, Tom G; Brede, Emily; Gatchel, Robert J

2014-06-01

Abnormal pretreatment flexion-relaxation in chronic disabling occupational lumbar spinal disorder patients has been shown to improve with functional restoration rehabilitation. Little is known about the effects of prior lumbar surgeries on flexion-relaxation and its responsiveness to treatment. To quantify the effect of prior lumbar surgeries on the flexion-relaxation phenomenon and its responsiveness to rehabilitative treatment. A prospective cohort study of chronic disabling occupational lumbar spinal disorder patients, including those with and without prior lumbar spinal surgeries. A sample of 126 chronic disabling occupational lumbar spinal disorder patients with prior work-related injuries entered an interdisciplinary functional restoration program and agreed to enroll in this study. Fifty-seven patients had undergone surgical decompression or discectomy (n=32) or lumbar fusion (n=25), and the rest had no history of prior injury-related spine surgery (n=69). At post-treatment, 116 patients were reevaluated, including those with prior decompressions or discectomies (n=30), lumbar fusions (n=21), and no surgery (n=65). A comparison group of 30 pain-free control subjects was tested with an identical assessment protocol, and compared with post-rehabilitation outcomes. Mean surface electromyography (SEMG) at maximum voluntary flexion; subject achievement of flexion-relaxation (SEMG≤3.5 μV); gross lumbar, true lumbar, and pelvic flexion ROM; and a pain visual analog scale self-report during forward bending task. Identical measures were obtained at pretreatment and post-treatment. Patients entered an interdisciplinary functional restoration program, including a quantitatively directed, medically supervised exercise process and a multimodal psychosocial disability management component. The functional restoration program was accompanied by a SEMG-assisted stretching training program, designed to teach relaxation of the lumbar musculature during end-range flexion

The Effects of Psoas Major and Lumbar Lordosis on Hip Flexion and Sprint Performance

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Copaver, Karine; Hertogh, Claude; Hue, Olivier

2012-01-01

In this study, we analyzed the correlations between hip flexion power, sprint performance, lumbar lordosis (LL) and the cross-sectional area (CSA) of the psoas muscle (PM). Ten young adults performed two sprint tests and isokinetic tests to determine hip flexion power. Magnetic resonance imaging was used to determine LL and PM CSA. There were…

Modification of Knee Flexion Angle Has Patient-Specific Effects on Anterior Cruciate Ligament Injury Risk Factors During Jump Landing.

Science.gov (United States)

Favre, Julien; Clancy, Caitlin; Dowling, Ariel V; Andriacchi, Thomas P

2016-06-01

The incidence of anterior cruciate ligament (ACL) injuries may be decreased through the use of intervention programs that focus on increasing the knee flexion angle during jump landing, which decreases strain on the ACL. To investigate whether intervention training designed to change the knee flexion angle during landing causes secondary changes in other known measures associated with the risk of ACL injuries and to examine the time points when these secondary measures change. Controlled laboratory study. A total of 39 healthy recreational athletes performed a volleyball block jump task in an instrumented gait laboratory. The participants first completed the jumps without any modification to their normal landing technique. They were then given oral instruction to land softly and to increase their knee flexion angle during landing. Lower body kinematics and kinetics were measured before and after the modification using an optoelectronic motion capture system. The knee flexion angle after the modification significantly increased from 11.2° to 15.2° at initial contact and from 67.8° to 100.7° at maximum flexion, and the time between initial contact and maximum flexion increased from 177.4 to 399.4 milliseconds. The flexion modification produced a substantial reduction in vertical ground-reaction force (243.1 to 187.8 %BW) with a concomitant reduction in the maximum flexion moment. Interestingly, the flexion modification only affected the abduction angle and abduction moment for the group of participants that landed in an initial adducted position before the modification and had no significant effect on the group that landed in an abducted position. Increasing the knee flexion angle during jump landing may be an effective intervention to improve knee biomechanical risk factors associated with an ACL injury. However, the fact that the flexion modification only influenced critical risk factors (the abduction angle and abduction moment) in participants who initially

The importance of bony impingement in restricting flexion after total knee arthroplasty: computer simulation model with clinical correlation.

Science.gov (United States)

Mizu-Uchi, Hideki; Colwell, Clifford W; Fukagawa, Shingo; Matsuda, Shuichi; Iwamoto, Yukihide; D'Lima, Darryl D

2012-10-01

We constructed patient-specific models from computed tomography data after total knee arthroplasty to predict knee flexion based on implant-bone impingement. The maximum flexion before impingement between the femur and the tibial insert was computed using a musculoskeletal modeling program (KneeSIM; LifeModeler, Inc, San Clemente, California) during a weight-bearing deep knee bend. Postoperative flexion was measured in a clinical cohort of 21 knees (low-flex group: 6 knees with 125° of flexion at 2 years). Average predicted flexion angles were within 2° of clinical measurements for the high-flex group. In the low-flex group, 4 cases had impingement involving the bone cut at the posterior condyle, and the average predicted knee flexion was 102° compared with 93° measured clinically. These results indicate that the level of the distal femoral resection should be carefully planned and that exposed bone proximal to the tips of the posterior condyles of the femoral component should be removed if there is risk of impingement. Copyright © 2012 Elsevier Inc. All rights reserved.

Clinical Evaluation of Fused/Ankylosed Hip with Severe Flexion Deformity after Conversion to Total Hip Arthroplasty

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Saroj Kumar Suwal

2016-06-01

Conclusions: THA is an effective treatment for ankylosed hip with severe flexion deformity although complications are noted more than routine hip arthroplasties. Keywords: ankylosed hip; fused hip; severe flexion deformity; total hip arthroplasty. | PubMed

Isokinetic evaluation of internal/external tibial rotation strength after the use of hamstring tendons for anterior cruciate ligament reconstruction.

Science.gov (United States)

Armour, Tanya; Forwell, Lorie; Litchfield, Robert; Kirkley, Alexandra; Amendola, Ned; Fowler, Peter J

2004-01-01

Evaluation of the knee after an anterior cruciate ligament reconstruction with the use of the semitendinosus and gracilis (hamstring) autografts has primarily focused on flexion and extension strength. The semitendinosus and gracilis muscles contribute to internal tibial rotation, and it has been suggested that harvest of these tendons for the purpose of an anterior cruciate ligament reconstruction contributes to internal tibial rotation weakness. Internal tibial rotation strength may be affected by the semitendinosus and gracilis harvest after anterior cruciate ligament reconstruction. Prospective evaluation of internal and external tibial rotation strength. Inclusion criteria for subjects (N = 30): unilateral anterior cruciate ligament reconstruction at least 2 years previously, a stable anterior cruciate ligament (problems after initial knee reconstruction, a normal contralateral knee, and the ability to comply with the testing protocol. In an attempt to minimize unwanted subtalar joint motion, subjects were immobilized using an ankle brace and tested at angular velocities of 60 degrees /s, 120 degrees /s, and 180 degrees /s at a knee flexion angle of 90 degrees . The mean peak torque measurements for internal rotation strength of the operative limb (60 degrees /s, 17.4 +/- 4.5 ft-lb; 120 degrees /s, 13.9 +/- 3.3 ft-lb; 180 degrees /s, 11.6 +/- 3.0 ft-lb) were statistically different compared to the nonoperated limb (60 degrees /s, 20.5 +/- 4.7 ft-lb; 120 degrees /s, 15.9 +/- 3.8 ft-lb; 180 degrees /s, 13.4 +/- 3.8 ft-lb) at 60 degrees /s (P = .012), 120 degrees /s (P = .036), and 180 degrees /s (P = .045). The nonoperative limb demonstrated greater strength at all speeds. The mean torque measurements for external rotation were statistically similar when compared to the nonoperated limb at all angular velocities. We have shown through our study that patients who undergo surgical intervention to repair a torn anterior cruciate ligament with the use of autogenous

The effects of joint aspiration and intra-articular corticosteroid injection on flexion reflex excitability, quadriceps strength and pain in individuals with knee synovitis: a prospective observational study.

Science.gov (United States)

Rice, David Andrew; McNair, Peter John; Lewis, Gwyn Nancy; Dalbeth, Nicola

2015-07-28

Substantial weakness of the quadriceps muscles is typically observed in patients with arthritis. This is partly due to ongoing neural inhibition that prevents the quadriceps from being fully activated. Evidence from animal studies suggests enhanced flexion reflex excitability may contribute to this weakness. This prospective observational study examined the effects of joint aspiration and intra-articular corticosteroid injection on flexion reflex excitability, quadriceps muscle strength and knee pain in individuals with knee synovitis. Sixteen patients with chronic arthritis and clinically active synovitis of the knee participated in this study. Knee pain flexion reflex threshold, and quadriceps peak torque were measured at baseline, immediately after knee joint aspiration alone and 5 ± 2 and 15 ± 2 days after knee joint aspiration and the injection of 40 mg of methylprednisolone acetate. Compared to baseline, knee pain was significantly reduced 5 (p = 0.001) and 15 days (p = 0.009) post intervention. Flexion reflex threshold increased immediately after joint aspiration (p = 0.009) and 5 (p = 0.01) and 15 days (p = 0.002) post intervention. Quadriceps peak torque increased immediately after joint aspiration (p = 0.004) and 5 (p = 0.001) and 15 days (p knee synovitis.

The Effect of Malrotation of Tibial Component of Total Knee Arthroplasty on Tibial Insert during High Flexion Using a Finite Element Analysis

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Kei Osano

2014-01-01

Full Text Available One of the most common errors of total knee arthroplasty procedure is a malrotation of tibial component. The stress on tibial insert is closely related to polyethylene failure. The objective of this study is to analyze the effect of malrotation of tibial component for the stress on tibial insert during high flexion using a finite element analysis. We used Stryker NRG PS for analysis. Three different initial conditions of tibial component including normal, 15° internal malrotation, and 15° external malrotation were analyzed. The tibial insert made from ultra-high-molecular-weight polyethylene was assumed to be elastic-plastic while femoral and tibial metal components were assumed to be rigid. Four nonlinear springs attached to tibial component represented soft tissues around the knee. Vertical load was applied to femoral component which rotated from 0° to 135° while horizontal load along the anterior posterior axis was applied to tibial component during flexion. Maximum equivalent stresses on the surface were analyzed. Internal malrotation caused the highest stress which arose up to 160% of normal position. External malrotation also caused higher stress. Implanting prosthesis in correct position is important for reducing the risk of abnormal wear and failure.

The effect of a rotator cuff tear and its size on three-dimensional shoulder motion.

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Kolk, Arjen; Henseler, Jan Ferdinand; de Witte, Pieter Bas; van Zwet, Erik W; van der Zwaal, Peer; Visser, Cornelis P J; Nagels, Jochem; Nelissen, Rob G H H; de Groot, Jurriaan H

2017-06-01

Rotator cuff-disease is associated with changes in kinematics, but the effect of a rotator cuff-tear and its size on shoulder kinematics is still unknown in-vivo. In this cross-sectional study, glenohumeral and scapulothoracic kinematics of the affected shoulder were evaluated using electromagnetic motion analysis in 109 patients with 1) subacromial pain syndrome (n=34), 2) an isolated supraspinatus tear (n=21), and 3) a massive rotator cuff tear involving the supraspinatus and infraspinatus (n=54). Mixed models were applied for the comparisons of shoulder kinematics between the three groups during abduction and forward flexion. In the massive rotator cuff-tear group, we found reduced glenohumeral elevation compared to the subacromial pain syndrome (16°, 95% CI [10.5, 21.2], protator cuff tears coincides with an increase in scapulothoracic lateral rotation compared to subacromial pain syndrome (11°, 95% CI [6.5, 15.2], protator cuff-tear group had substantially less glenohumeral elevation and more scapulothoracic lateral rotation compared to the other groups. These observations suggest that the infraspinatus is essential to preserve glenohumeral elevation in the presence of a supraspinatus tear. Shoulder kinematics are associated with rotator cuff-tear size and may have diagnostic potential. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rotator cuff tendon connections with the rotator cable.

Science.gov (United States)

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

Knee Flexion and Daily Activities in Patients following Total Knee Replacement: A Comparison with ISO Standard 14243

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Markus A. Wimmer

2015-01-01

Full Text Available Walking is only one of many daily activities performed by patients following total knee replacement (TKR. The purpose of this study was to examine the hypotheses (a that subject activity characteristics are correlated with knee flexion range of motion (ROM and (b that there is a significant difference between the subject’s flexion/extension excursion throughout the day and the ISO specified input for knee wear testing. In order to characterize activity, the number of walking and stair stepping cycles, the time spent with dynamic and stationary activities, the number of activity sequences, and the knee flexion/extension excursion of 32 TKR subjects were collected during daily activity. Flexion/extension profiles were compared with the ISO 14243 simulator input profile using a level crossing classification algorithm. Subjects took an average of 3102 (range: 343–5857 walking cycles including 65 (range: 0–319 stair stepping cycles. Active and passive ROMs were positively correlated with stair walking time, stair step counts, and stair walking sequences. Simulated knee motion according to ISO showed significantly fewer level crossings at the flexion angles 20–40° and beyond 50° than those measured with the monitor. This suggests that implant wear testing protocols should contain more cycles and a variety of activities requiring higher knee flexion angles with incorporated resting/transition periods to account for the many activity sequences.

Finger island flaps for treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints

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T. S. Antonova

2016-12-01

Full Text Available Soft tissue defect will form after operative treatment of the dermato-desmogenic flexion contractures of fingers interphalangeal joints of the 2–3 grades after excision of the scar. Using the island flaps (Littler at the central vascular pedicle is one of the classical methods of plastic closure of such defects. Goal. To study the effectiveness of the surgical treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints of the fingers by using finger island flaps at the central vascular or neuro-vascular pedicle. Materials and methods. 14 operations were carried out on 13 patients for removing dermato-desmogenic flexion contractures of proximal interphalangeal (PIP joints of triphalangeal fingers over a 2-year period (2013–2015. The group included patients with a flexion contracture of the 2–3 grades PIP joints of triphalangeal fingers. Operations were performed on average 5 months after the injury (from 1.5 up to 16 months. Finger island flap in all cases was taken from adjacent finger by using the blood supply of their common finger artery. In all cases the island flap on the central pedicel was used, in 9 cases digital nerve was included in the pedicle (Littler. Closure of donor wound was made with free-skin grafts. Permanent splinting of the hand with extension of the interphalangeal joints and moderate flexion of the metacarpophalangeal joints were performed during 7–8 days after surgery, then exercise therapy was prescribed. Results. The results were estimated 6 and 12 months after surgery. All the results were regarded as excellent. In 5 cases of using the flap on a vascular pedicle flap hypoesthesia was detected, that has not led to dysfunction of the hand. Contracture recurrence during follow-up was not observed. Conclusions. Using the surgery for treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints of the fingers with the island flaps at the central vascular or neuro

Déficit bilateral nos movimentos de flexão e extensão de perna e flexão do cotovelo Déficit bilateral en los movimientos de flexion y extension de la pierna y flexion del codo Bilateral deficit in leg flexion and extension and elbow flexion movements

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Christianne Pereira Giesbrecht Chaves

2004-12-01

áxima (CM en la flexión y extensión de pierna e flexión del de codo aisladamente y entre la suma de esos dos resultados con aquel desarrollado simultaneamente por las dos piernas y los dos brazos, respectivamente. Sometemos a 60 indivíduos al ejercicio de flexión y extensión de pierna y a flexión de codo a un test de 1RM. Los resultados para los movimientos de flexión y extensión de pierna y flexión de codo izquierdos y derechos en la CM fueron de 31,6 (± 7,9, 32,0 (± 8,0, 20,2 (± 9,2, 20,2 (± 9,8, 29,3 (± 13,9 e 29,8 (± 14,1 kg respectivamente, y se mostraron similares (p > 0,05 y fuertemente asociados (r = 0,96, 0,96 e 0,98. Comparando la suma de los valores unilaterales con los de ejecución bilateral, la CM presentó una diferencia significativa para los movimientos de extensión de pierna (p = 0,04 y flexión de codo (p = 0,03, el mismo no fué observado en el movimiento de flexión de pierna (p = 0,75. Este resultado puede ser explicado por el menor incremento de carga - dos kilos y medio en este último movimiento en relación a los dos movimientos anteriores - cinco kilos. A pesar de la mayoría de los sujetos sean diestros, no hubo diferencias unilaterales en la CM a pesar de no todos estar entrenados. La suma de los resultados unilaterales fué mayor en 9,8% y 4,0% para los movimientos de extensión de la pierna y flexión del codo, respectivamente, de aquel obtenido bilateralmente, mostrando, probablemente una limitación central en la coordenación motora de un movimiento complejo hecho en máxima velocidad y con carga elevada. Por otro lado, en el movimiento de flexión de pierna, la suma de los resultados unilaterales fué inferior a la bilateral (-0,6%, presentando un posible aprendizage del movimiento y adaptación al entrenamiento con pesos a partir de las doce semanas.Endurance exercises (EE may be performed unilaterally and bilaterally. The objective was to compare the maximum load (ML in leg flexion and extension and elbow flexion alone

Kinematics and Dynamics Analysis of a 3-DOF Upper-Limb Exoskeleton with an Internally Rotated Elbow Joint

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Xin Wang

2018-03-01

Full Text Available The contradiction between self-weight and load capacity of a power-assisted upper-limb exoskeleton for material hanging is unresolved. In this paper, a non-anthropomorphic 3-degree of freedom (DOF upper-limb exoskeleton with an internally rotated elbow joint is proposed based on an anthropomorphic 5-DOF upper-limb exoskeleton for power-assisted activity. The proposed 3-DOF upper-limb exoskeleton contains a 2-DOF shoulder joint and a 1-DOF internally rotated elbow joint. The structural parameters of the 3-DOF upper-limb exoskeleton were determined, and the differences and singularities of the two exoskeletons were analyzed. The workspace, the joint torques and the power consumption of two exoskeletons were analyzed by kinematics and dynamics, and an exoskeleton prototype experiment was performed. The results showed that, compared with a typical anthropomorphic upper-limb exoskeleton, the non-anthropomorphic 3-DOF upper-limb exoskeleton had the same actual workspace; eliminated singularities within the workspace; improved the elbow joint force situation; and the maximum elbow joint torque, elbow external-flexion/internal-extension and shoulder flexion/extension power consumption were significantly reduced. The proposed non-anthropomorphic 3-DOF upper-limb exoskeleton can be applied to a power-assisted upper-limb exoskeleton in industrial settings.

Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic (ECoG Signals

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Zuoguan eWang

2011-11-01

Full Text Available Brain-computer interfaces (BCIs use brain signals to convey a user's intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG recordings from the surface of the brain in humans can give information about kinematic parameters (eg{} hand velocity or finger flexion. The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the anatomic constraints and dynamic constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS. Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation.

COMPARATIVE BIOMECHANICAL ANALYSES OF SQUAT JUMP WITHOUT AND WITH FLEXION IN KNEE JOINT

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Saša Bubanj

2009-11-01

Full Text Available In sports hall of Faculty of sports and physical education in Niš, student demon- strated technique of squat jump – without and with flexion in knee joint. Elements of technique were recorded by using one digital video camera in sagital plane. By using comparative kinematics analyses, there were establish differences in values of kinema- tics parametres of different body segments. Bigger elevation of body centre of gravity was ascertain at bounce without flexion in knee joint.

Shoulder rotator isokinetic strength profile in young swimmers

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Nuno Miguel Prazeres Batalha

2012-08-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n5p545  Considering that some studies suggest that shoulder rotators muscle imbal­ances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i to describe the muscle balance, fatigue and isokinetic strength profile of the shoulder rotators in young swimmers; ii to compare the results between swimmers and a group of young non-practitioners; iii to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg. The evaluation was performed in the sitting position (90° abduction and elbow flexion at 60º.s-1 and 180º.s-1 angular speeds using an isokinetic dynamometer (Biodex System 3. The results of the fatigue ratios revealed no differences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL and 77.89 ± 15,23% in the non-dominant limb (NDL for assessments at 60º.s-1. At 180º.s-1, ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and differed from non-practitioners in the ability to produce power with the internal rotators, which was significantly higher in the former group.

Entretien sur la psychanalyse: réflexions en marge

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Giuseppe Martini

2016-08-01

Full Text Available L’auteur propose ici un commentaire sur les points les plus importants de son entretien de février 2003 avec Paul Ricœur consacré aux rapports entre herméneutique et psychanalyse. Bien que le philosophe se situe dans une réelle continuité par rapport à sa contribution de 1965, il enrichit toutefois sa réflexion philosophique sur la psychanalyse en proposant plusieurs innovations, en ce qui concerne plus particulièrement les thèmes du récit, du soi et de l’éthique. Dans les conclusions de son commentaire, l’auteur souligne l’importance des concepts d’“irreprésentable” et d’“intraduisible”: non seulement, en effet, ces concepts sont dans la ligne de nombreuses contributions de la psychanalyse contemporaine, mais la profondeur de la réflexion ricœurienne augmente en outre leur potentiel théorique et même clinique.

Vibration of rotating-shaft design spindles with flexible bases

Science.gov (United States)

Tseng, Chaw-Wu

The purpose of this study is to demonstrate an accurate mathematical model predicting forced vibration of rotating-shaft HDD spindle motors with flexible stationary parts. The mathematical model consists of three parts: a rotating part, a stationary part, and bearings. The rotating part includes a flexible hub, a flexible shaft press-fit into the hub, and N elastic disks mounted on the hub. The stationary part can include motor bracket (stator), base casting, and top cover. The bearings under consideration can be ball bearings or hydrodynamic bearings (HDB). The rotating disks are modelled through the classical plate theory. The rotating part (except the disks) and the stationary part are modelled through finite element analyses (FEA). With mode shapes and natural frequencies obtained from FEA, the kinetic and potential energies of the rotating and stationary parts are formulated and discretized to compensate for the gyroscopic effects from rotation. Finally, use of Lagrange equation results in the equations of motion. To verify the mathematical model, frequency response functions are measured experimentally for an HDB spindle carrying two identical disks at motor and drive levels. Experimental measurements agree very well with theoretical predictions not only in resonance frequency but also in resonance amplitude.

Intrathecal volume changes in lumbar spinal canal stenosis following extension and flexion: An experimental cadaver study.

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Teske, Wolfram; Schwert, Martin; Zirke, Sonja; von Schulze Pellengahr, Christoph; Wiese, Matthias; Lahner, Matthias

2015-01-01

The spinal canal stenosis is a common disease in elderly. The thecal sac narrowing is considered as the anatomical cause for the disease. There is evidence that the anatomical proportions of the lumbar spinal canal are influenced by postural changes. The liquor volume shift during these postural changes is a valuable parameter to estimate the dynamic qualities of this disease. The aim of this human cadaver study was the determination of intrathecal fluid volume changes during the lumbar flexion and the extension. A special measuring device was designed and built for the study to investigate this issue under controlled conditions. The measuring apparatus fixed the lumbar spine firmly and allowed only flexion and extension. The dural sac was closed water tight. The in vitro changes of the intrathecal volumes during the motion cycle were determined according to the principle of communicating vessels. Thirteen human cadaver spines from the Institute of Anatomy were examined in a test setting with a continuous adjustment of motion. The diagnosis of the lumbar spinal stenosis was confirmed by a positive computer tomography prior testing. The volume changes during flexion and extension cycles were measured stepwise in a 2 degree distance between 18° flexion and 18° extension. Three complete series of measurements were performed for each cadaver. Two specimens were excluded because of fluid leaks from further investigation. The flexion of the lumbar spine resulted in an intrathecal volume increase. The maximum volume effects were seen in the early flexion positions of 2° and 4°. The spine reclination resulted in a volume reduction. The maximum extension effect was seen between 14° and 16°. According to our results, remarkable volume effects were seen in the early movements of the lumbar spine especially for the flexion. The results support the concept of the spinal stenosis as a dynamic disease and allow a better understanding of the pathophysiology of this

Flexion synergy overshadows flexor spasticity during reaching in chronic moderate to severe hemiparetic stroke.

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Ellis, Michael D; Schut, Ingrid; Dewald, Julius P A

2017-07-01

Pharmaceutical intervention targets arm flexor spasticity with an often-unsuccessful goal of improving function. Flexion synergy is a related motor impairment that may be inadvertently neglected. Here, flexor spasticity and flexion synergy are disentangled to determine their contributions to reaching dysfunction. Twenty-six individuals participated. A robotic device systematically modulated shoulder abduction loading during ballistic reaching. Elbow muscle electromyography data were partitioned into windows delineated by elbow joint velocity allowing for the separation of synergy- and spasticity-related activation. Reaching velocity decreased with abduction loading (psynergy increased with abduction loading (psynergy is the predominant contributor to reaching dysfunction while flexor spasticity appears only relevant during unnaturally occurring passively supported movement. Interventions targeting flexion synergy should be leveraged in future stroke recovery trials. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

The effect of hip positioning on the projected femoral neck-shaft angle: a modeling study.

Science.gov (United States)

Bhashyam, Abhiram R; Rodriguez, Edward K; Appleton, Paul; Wixted, John J

2018-04-03

The femoral neck-shaft angle (NSA) is used to restore normal hip geometry during hip fracture repair. Femoral rotation is known to affect NSA measurement, but the effect of hip flexion-extension is unknown. The goals of this study were to determine and test mathematical models of the relationship between hip flexion-extension, femoral rotation and NSA. We hypothesized that hip flexion-extension and femoral rotation would result in NSA measurement error. Two mathematical models were developed to predict NSA in varying degrees of hip flexion-extension and femoral rotation. The predictions of the equations were tested in vitro using a model that varied hip flexion-extension while keeping rotation constant, and vice versa. The NSA was measured from an AP radiograph obtained with a C-arm. Attributable measurement error based on hip positioning was calculated from the models. The predictions of the model correlated well with the experimental data (correlation coefficient = 0.82 - 0.90). A wide range of patient positioning was found to result in less than 5-10 degree error in the measurement of NSA. Hip flexion-extension and femoral rotation had a synergistic effect in measurement error of the NSA. Measurement error was minimized when hip flexion-extension was within 10 degrees of neutral. This study demonstrates that hip flexion-extension and femoral rotation significantly affect the measurement of the NSA. To avoid inadvertently fixing the proximal femur in varus or valgus, the hip should be positioned within 10 degrees of neutral flexion-extension with respect to the C-arm to minimize positional measurement error. N/A, basic science study.

Global analysis of sagittal spinal alignment in major deformities: correlation between lack of lumbar lordosis and flexion of the knee.

Science.gov (United States)

Obeid, Ibrahim; Hauger, Olivier; Aunoble, Stéphane; Bourghli, Anouar; Pellet, Nicolas; Vital, Jean-Marc

2011-09-01

It has become well recognised that sagittal balance of the spine is the result of an interaction between the spine and the pelvis. Knee flexion is considered to be the last compensatory mechanism in case of sagittal imbalance, but only few studies have insisted on the relationship between spino-pelvic parameters and lower extremity parameters. Correlation between the lack of lumbar lordosis and knee flexion has not yet been established. A retrospective study was carried out on 28 patients with major spinal deformities. The EOS system was used to measure spinal and pelvic parameters and the knee flexion angle; the lack of lumbar lordosis was calculated after prediction of lumbar lordosis with two different formulas. Correlation analysis between the different measured parameters was performed. Lumbar lordosis correlated with sacral slope (r = -0.71) and moderately with knee flexion angle (r = 0.42). Pelvic tilt correlated moderately with knee flexion angle (r = 0.55). Lack of lumbar lordosis correlated best with knee flexion angle (r = 0.72 and r = 0.63 using the two formulas, respectively). Knee flexion as a compensatory mechanism to sagittal imbalance was well correlated to the lack of lordosis and, depending on the importance of the former parameter, the best procedure to correct sagittal imbalance could be chosen.

Does successful rotator cuff repair improve muscle atrophy and fatty infiltration of the rotator cuff? A retrospective magnetic resonance imaging study performed shortly after surgery as a reference.

Science.gov (United States)

Hamano, Noritaka; Yamamoto, Atsushi; Shitara, Hitoshi; Ichinose, Tsuyoshi; Shimoyama, Daisuke; Sasaki, Tsuyoshi; Kobayashi, Tsutomu; Kakuta, Yohei; Osawa, Toshihisa; Takagishi, Kenji

2017-06-01

Muscle atrophy and fatty infiltration in the rotator cuff muscles are often observed in patients with chronic rotator cuff tears. The recovery from these conditions has not been clarified. Ninety-four patients were included in this study. The improvement in muscle atrophy and fatty infiltration in successfully repaired rotator cuff tears was evaluated by magnetic resonance imaging at 1 year and 2 years after surgery and was compared with muscle atrophy and fatty infiltration observed on magnetic resonance imaging at 2 weeks after surgery to discount any changes due to the medial retraction of the torn tendon. The patients' muscle strength was evaluated in abduction and external rotation. Muscle atrophy and fatty infiltration of the supraspinatus were significantly improved at 2 years after surgery in comparison to 2 weeks after surgery. The subjects' abduction and external rotation strength was also significantly improved at 2 years after surgery in comparison to the preoperative values. Patients whose occupation ratio was improved had a better abduction range of motion, stronger abduction strength, and higher Constant score. Patients whose fatty infiltration was improved had a better range of motion in flexion and abduction, whereas the improvements of muscle strength and the Constant score were similar in the group that showed an improvement of fatty infiltration and the group that did not. Muscle atrophy and fatty infiltration can improve after rotator cuff repair. The strengths of abduction and external rotation were also improved at 2 years after surgery. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

ANALYSIS OF ISOKINETIC KNEE EXTENSION / FLEXION IN MALE ELITE ADOLESCENT WRESTLERS

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Sanli Sadi Kurdak

2005-12-01

Full Text Available Wrestling requires strength of the upper and lower body musculature which is critical for the athletic performance. Evaluation of the adolescent's skeletal muscle is important to understand body movement, especially including those involved in sports. Strength, power and endurance capacity are defined as parameters of skeletal muscle biomechanical properties. The isokinetic dynamometer is an important toll for making this type of evaluation. However, load range phase of range of motion has to be considered to interpret the data correctly. With this in mind we aimed to investigate the lover body musculature contractile characteristics of adolescent wrestlers together with detailed analyses of load range phase of motion. Thirteen boys aged 12 - 14 years participated to this study. Concentric load range torque, work and power of knee extension and flexion were measured by a Cybex Norm dynamometer at angular velocities from 450°/sec to 30°/sec with 30°/sec decrements for each set. None of the wrestlers were able to attain load range for angular velocities above 390°/sec and 420°/sec for extension and flexion respectively. Detailed analyses of the load range resulted in statistically significant differences in the normalized load range peak torque for extension at 270°/sec (1.44 ± 0.28 Nm·kg-1 and 1.14 ± 0.28 Nm·kg-1 for total and load range peak torque respectively, p < 0.05, and for flexion at 300°/sec (1.26 ± 0.28 Nm·kg-1 and 1.03 ± 0.23 Nm·kg-1 for total and load range peak torque respectively, p < 0.05, compared to total peak torque data. Similarly, the significant difference was found for the work values at 90°/sec (1.91 ± 0.23 Nm·kg-1 and 1.59 ± 0.24 Nm·kg-1 for total and load range work respectively for extension and 1.73 ± 0.21 Nm·kg-1 and 1.49 ± 0.19 Nm·kg-1 for total and load range work respectively for flexion, p < 0.05, and was evident at higher angular velocities (p < 0.001 for both extension and flexion. At

Knee extension and flexion: MR delineation of normal and torn anterior cruciate ligaments

Energy Technology Data Exchange (ETDEWEB)

Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru; Anno, Izumi; Itai, Yuji [Univ. of Tsukuba, Ibaraki (Japan)

1996-03-01

Our goal was to assess the effect of joint position of semiflexed and extended knees in MR delineation of the anterior cruciate ligament (ACL). With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semiflexed position (average 45{degrees} of flexion) within the magnet bore. Sets of oblique sagittal MR images were obtained for both extended and flexed knee positions. Thirty-two knees with intact ACLs and 43 knees with arthroscopically proven ACL tears were evaluated. Two observers compared paired MR images of both extended and flexed positions and rated them by a relative three point scale. Anatomic correlation in MR images was obtained by a cadaveric knee with incremental flexion. The MR images of flexed knees were more useful than of extended knees in 53% of the case reviews of femoral attachments and 36% of reviews of midportions of normal ACLs. Compared with knee extensions, the MR images for knee flexion provided better clarity in 48% of reviews of disrupted sites and 52% of residual bundles of torn ACLs. Normal ACL appeared taut in the knee extension and lax in semiflexion. Compared with MR images of knees in extension, MR images of knees in flexion more clearly delineate the femoral side of the ligament with wider space under the intercondylar roof and with decreased volume-averaging artifacts, providing superior visualization of normal and torn ACLs. 13 refs., 7 figs., 1 tab.

Rotation sensor switch

International Nuclear Information System (INIS)

Sevec, J.B.

1978-01-01

A protective device to provide a warning if a piece of rotating machinery slows or stops is comprised of a pair of hinged weights disposed to rotate on a rotating shaft of the equipment. When the equipment is rotating, the weights remain in a plane essentially perpendicular to the shaft and constitute part of an electrical circuit that is open. When the shaft slows or stops, the weights are attracted to a pair of concentric electrically conducting disks disposed in a plane perpendicular to the shaft and parallel to the plane of the weights when rotating. A disk magnet attracts the weights to the electrically conducting plates and maintains the electrical contact at the plates to complete an electrical circuit that can then provide an alarm signal

Lateral collateral ligament of the elbow joint

DEFF Research Database (Denmark)

Olsen, Bo Sanderhoff; Vaesel, M T; Søjbjerg, Jens Ole

1996-01-01

The structure and kinematics of the lateral collateral ligament of the elbow joint were investigated in 10 cadaveric specimens. The lateral collateral ligament was observed to be a distinct part of the lateral collateral ligament complex. It contains posterior fibers that pass through the annular....... Division of the posterolateral capsule caused no further laxity. Cutting the lateral collateral ligament induced a maximum laxity of 11.8 degrees at 110 degrees of flexion in forced varus and a maximum laxity of 20.6 degrees at 110 degrees of flexion in forced external rotation. The corresponding maximal...... posterior radial head translation was observed at 80 degrees to 100 degrees of flexion and was 5.7 mm in forced varus and 8.1 mm in forced external rotation. This study suggests the lateral collateral ligament to be an important stabilizer of the humeroulnar joint and the radial head in forced varus...

Are magnetic resonance flexion views useful in evaluating the cervical spine of patients with rheumatoid arthritis?

Energy Technology Data Exchange (ETDEWEB)

Reijnierse, M.; Kroon, H.M.; Bloem, J.L. [Dept. of Radiology, Leiden University Medical Center (Netherlands); Breedveld, F.C. [Dept. of Rheumatology, Leiden University Medical Center, Leiden (Netherlands); Hansen, B. [Dept. of Medical Statistics, Leiden University Medical Center, Leiden (Netherlands); Pope, T.L. [Dept. of Diagnostic Radiology, Bowman Gray School of Medicine, Winston-Salem (United States)

2000-02-01

Objective. To determine whether MR imaging in flexion adds value relative to imaging in the neutral position with respect to displaying involvement of the subarachnoid space, brainstem and spinal cord. Design and patients. T1-weighted MR images of the cervical spine in 42 rheumatoid arthritis patients with cervical spine involvement were obtained and analyzed prospectively. We assessed changes between images obtained in the neutral position and following active flexion, especially horizontal atlantoaxial and subaxial motion, presence or absence of brainstem compression, subarachnoid space involvement at the atlantoaxial and subaxial level and the cervicomedullary angle. Vertical atlantoaxial subluxation and the amount of pannus were correlated with motion and change in subarachnoid space. Results. The flexion images showed horizontal atlantoaxial motion in 21 patients and subaxial motion in one patient. The flexion view displayed brainstem compression in only one patient. Involvement of the subarachnoid space increased at the atlantoaxial level in eight (19%) patients (P=0.004) and at the level below C2 in five (12%) patients (P=0.03). There were no patients with a normal subarachnoid space in neutral position and compression in the flexed position. The cervicomedullary angle changed significantly with flexion. Vertical atlantoaxial subluxation and the amount of pannus did not show a significant correlation with motion or subarachnoid space involvement. Conclusion. MR imaging in the flexed position shows a statistically significant narrowing of the subarachnoid space at the atlantoaxial level and below C2. Cord compression is only observed on flexion views if the subarachnoid space in neutral position is already decreased. MR imaging in the flexed position might be useful, since subarachnoid space involvement may be an indicator for the development of neurologic dysfunction. (orig.)

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors.

Science.gov (United States)

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2010-10-21

Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

Directory of Open Access Journals (Sweden)

Kumar Dinesh

2010-10-01

Full Text Available Abstract Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS, Mean absolute value (MAV, Variance (VAR and Waveform length (WL and the proposed fractal features: fractal dimension (FD and maximum fractal length (MFL were computed. Multi-variant analysis of variance (MANOVA was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination

The rotate-plus-shift C-arm trajectory. Part I. Complete data with less than 180° rotation

International Nuclear Information System (INIS)

Ritschl, Ludwig; Fleischmann, Christof; Kuntz, Jan; Kachelrieß, Marc

2016-01-01

Purpose: In the last decade, C-arm-based cone-beam CT became a widely used modality for intraoperative imaging. Typically a C-arm CT scan is performed using a circular or elliptical trajectory around a region of interest. Therefore, an angular range of at least 180° plus fan angle must be covered to ensure a completely sampled data set. However, mobile C-arms designed with a focus on classical 2D applications like fluoroscopy may be limited to a mechanical rotation range of less than 180° to improve handling and usability. The method proposed in this paper allows for the acquisition of a fully sampled data set with a system limited to a mechanical rotation range of at least 180° minus fan angle using a new trajectory design. This enables CT like 3D imaging with a wide range of C-arm devices which are mainly designed for 2D imaging. Methods: The proposed trajectory extends the mechanical rotation range of the C-arm system with two additional linear shifts. Due to the divergent character of the fan-beam geometry, these two shifts lead to an additional angular range of half of the fan angle. Combining one shift at the beginning of the scan followed by a rotation and a second shift, the resulting rotate-plus-shift trajectory enables the acquisition of a completely sampled data set using only 180° minus fan angle of rotation. The shifts can be performed using, e.g., the two orthogonal positioning axes of a fully motorized C-arm system. The trajectory was evaluated in phantom and cadaver examinations using two prototype C-arm systems. Results: The proposed trajectory leads to reconstructions without limited angle artifacts. Compared to the limited angle reconstructions of 180° minus fan angle, image quality increased dramatically. Details in the rotate-plus-shift reconstructions were clearly depicted, whereas they are dominated by artifacts in the limited angle scan. Conclusions: The method proposed here employs 3D imaging using C-arms with less than 180° rotation

The rotate-plus-shift C-arm trajectory. Part I. Complete data with less than 180° rotation

Energy Technology Data Exchange (ETDEWEB)

Ritschl, Ludwig; Fleischmann, Christof [Ziehm Imaging GmbH, Donaustraße 31, Nürnberg 90451 (Germany); Kuntz, Jan, E-mail: j.kuntz@dkfz.de; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany)

2016-05-15

Purpose: In the last decade, C-arm-based cone-beam CT became a widely used modality for intraoperative imaging. Typically a C-arm CT scan is performed using a circular or elliptical trajectory around a region of interest. Therefore, an angular range of at least 180° plus fan angle must be covered to ensure a completely sampled data set. However, mobile C-arms designed with a focus on classical 2D applications like fluoroscopy may be limited to a mechanical rotation range of less than 180° to improve handling and usability. The method proposed in this paper allows for the acquisition of a fully sampled data set with a system limited to a mechanical rotation range of at least 180° minus fan angle using a new trajectory design. This enables CT like 3D imaging with a wide range of C-arm devices which are mainly designed for 2D imaging. Methods: The proposed trajectory extends the mechanical rotation range of the C-arm system with two additional linear shifts. Due to the divergent character of the fan-beam geometry, these two shifts lead to an additional angular range of half of the fan angle. Combining one shift at the beginning of the scan followed by a rotation and a second shift, the resulting rotate-plus-shift trajectory enables the acquisition of a completely sampled data set using only 180° minus fan angle of rotation. The shifts can be performed using, e.g., the two orthogonal positioning axes of a fully motorized C-arm system. The trajectory was evaluated in phantom and cadaver examinations using two prototype C-arm systems. Results: The proposed trajectory leads to reconstructions without limited angle artifacts. Compared to the limited angle reconstructions of 180° minus fan angle, image quality increased dramatically. Details in the rotate-plus-shift reconstructions were clearly depicted, whereas they are dominated by artifacts in the limited angle scan. Conclusions: The method proposed here employs 3D imaging using C-arms with less than 180° rotation

Can total knee arthroplasty (TKA) achieve its goal in knee flexion floor activity of Thai Buddhist monks?

Science.gov (United States)

Sresuriyasawad, Viriya

2012-10-01

To study knee's angulation required for Thai Buddhist monks whose activity based on floor sitting basis. And to identify an inter-observer reliability of knee flexion measurement based on radiologic reading. Descriptive analysis study comprised of measuring bilateral knee flexing angulation in 4 postures of floor activities; kneeling, monk's position in both right and left manner and sit cross-legged position, in 35 Thai Buddhist monks at Priest Hospital using plain radiograph image. The radiograph imaging for each patient was performed by one radiologist and two orthopedics. The measurement result was also analyzed for inter-observer reliability. Mean knee flexion angle in kneel, left monk's position, right monk's position and sit cross-legged postures were 163.21, 146.49, 148.89 and 138.38 degree, respectively. No statistical difference between knee flexion measurements among 3 investigators. Daily floor activity of Thai Buddhist monks need more flexion capacity than that can achieve by total knee arthroplasty instrument using nowadays.

A comparison between flexible electrogoniometers, inclinometers and three-dimensional video analysis system for recording neck movement.

Science.gov (United States)

Carnaz, Letícia; Moriguchi, Cristiane S; de Oliveira, Ana Beatriz; Santiago, Paulo R P; Caurin, Glauco A P; Hansson, Gert-Åke; Coury, Helenice J C Gil

2013-11-01

This study compared neck range of movement recording using three different methods goniometers (EGM), inclinometers (INC) and a three-dimensional video analysis system (IMG) in simultaneous and synchronized data collection. Twelve females performed neck flexion-extension, lateral flexion, rotation and circumduction. The differences between EGM, INC, and IMG were calculated sample by sample. For flexion-extension movement, IMG underestimated the amplitude by 13%; moreover, EGM showed a crosstalk of about 20% for lateral flexion and rotation axes. In lateral flexion movement, all systems showed similar amplitude and the inter-system differences were moderate (4-7%). For rotation movement, EGM showed a high crosstalk (13%) for flexion-extension axis. During the circumduction movement, IMG underestimated the amplitude of flexion-extension movements by about 11%, and the inter-system differences were high (about 17%) except for INC-IMG regarding lateral flexion (7%) and EGM-INC regarding flexion-extension (10%). For application in workplace, INC presents good results compared to IMG and EGM though INC cannot record rotation. EGM should be improved in order to reduce its crosstalk errors and allow recording of the full neck range of movement. Due to non-optimal positioning of the cameras for recording flexion-extension, IMG underestimated the amplitude of these movements. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Validity and intra-rater reliability of an android phone application to measure cervical range-of-motion.

Science.gov (United States)

Quek, June; Brauer, Sandra G; Treleaven, Julia; Pua, Yong-Hao; Mentiplay, Benjamin; Clark, Ross Allan

2014-04-17

Concurrent validity and intra-rater reliability using a customized Android phone application to measure cervical-spine range-of-motion (ROM) has not been previously validated against a gold-standard three-dimensional motion analysis (3DMA) system. Twenty-one healthy individuals (age:31 ± 9.1 years, male:11) participated, with 16 re-examined for intra-rater reliability 1-7 days later. An Android phone was fixed on a helmet, which was then securely fastened on the participant's head. Cervical-spine ROM in flexion, extension, lateral flexion and rotation were performed in sitting with concurrent measurements obtained from both a 3DMA system and the phone.The phone demonstrated moderate to excellent (ICC = 0.53-0.98, Spearman ρ = 0.52-0.98) concurrent validity for ROM measurements in cervical flexion, extension, lateral-flexion and rotation. However, cervical rotation demonstrated both proportional and fixed bias. Excellent intra-rater reliability was demonstrated for cervical flexion, extension and lateral flexion (ICC = 0.82-0.90), but poor for right- and left-rotation (ICC = 0.05-0.33) using the phone. Possible reasons for the outcome are that flexion, extension and lateral-flexion measurements are detected by gravity-dependent accelerometers while rotation measurements are detected by the magnetometer which can be adversely affected by surrounding magnetic fields. The results of this study demonstrate that the tested Android phone application is valid and reliable to measure ROM of the cervical-spine in flexion, extension and lateral-flexion but not in rotation likely due to magnetic interference. The clinical implication of this study is that therapists should be mindful of the plane of measurement when using the Android phone to measure ROM of the cervical-spine.

Neck muscle fatigue alters the cervical flexion relaxation ratio in sub-clinical neck pain patients.

Science.gov (United States)

Zabihhosseinian, Mahboobeh; Holmes, Michael W R; Ferguson, Brad; Murphy, Bernadette

2015-06-01

The cervical flexion relaxation ratio is lower in neck pain patients compared to healthy controls. Fatigue modulates the onset and offset angles of the silent period in both the lumbar and cervical spine in healthy individuals; however, this response has not been studied with neck pain patients. The purpose of this study was to determine if cervical extensor fatigue would alter the parameters of the cervical flexion relaxation more in a neck pain group than a healthy control group. Thirteen healthy and twelve neck pain patients participated. Cervical extensor activity was examined bilaterally and kinematics of the neck and head were collected. An isometric, repetitive neck extension task at 70% of maximum elicited fatigue. Participants performed 3 trials of maximal cervical flexion both pre and post fatigue. The healthy controls and neck pain groups fatigued after 56 (41) and 39 (31) repetitions, respectively. There was a significant interaction effect for the flexion relaxation ratio between the control and neck pain groups from pre to post fatigue trials (F1,96=22.67, P=0.0001), but not for onset and offset angles (F1, 96=0.017, P=0.897), although the onset and offset angles did decrease significantly for both groups following fatigue (F1,96=9.26, P=0.002). Individuals with mild to moderate neck pain have significant differences in their neuromuscular control relative to controls, experienced myoelectric fatigue with fewer repetitions in a shorter time, had a lower cervical flexion relaxation ratio at baseline and had an inability to decrease this ratio further in response to fatigue. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of esophageal flexion level on the surgical outcome in patients with sigmoid esophageal achalasia.

Science.gov (United States)

Tsuboi, Kazuto; Omura, Nobuo; Yano, Fumiaki; Hoshino, Masato; Yamamoto, Se-Ryung; Akimoto, Shunsuke; Masuda, Takahiro; Kashiwagi, Hideyuki; Yanaga, Katsuhiko

2017-11-01

Esophageal achalasia can be roughly divided into non-sigmoid and sigmoid types. Laparoscopic surgery has been reported to be less than optimally effective for sigmoid type. The aim of this study was to examine the impact of the esophageal flexion level on the clinical condition and surgical outcomes of patients with sigmoid esophageal achalasia. The subjects were 36 patients with sigmoid esophageal achalasia who had been observed for >1 year after surgery. The subjects were divided into sigmoid type (Sg) and advanced sigmoid type (aSg) groups based on the flexion level of the lower esophagus to compare their clinical parameters and surgical outcomes. The Sg and aSg groups included 26 (72%) and 10 subjects, respectively. There were no marked differences in the clinical parameters or surgical outcomes between the two groups. However, the clearance rate calculated using the timed barium esophagogram was lower in the aSg group than in the Sg group. No differences were found in the postoperative symptom scores between the two groups, and both reported a high level of satisfaction. Although laparoscopic surgery for symptoms of sigmoid esophageal achalasia was highly successful regardless of the flexion level, the improvement in esophageal clearance was lower when the flexion level was higher.

Evaluation of movements of lower limbs in non-professional ballet dancers: hip abduction and flexion

Directory of Open Access Journals (Sweden)

Valenti Erica E

2011-08-01

Full Text Available Abstract Background The literature indicated that the majority of professional ballet dancers present static and active dynamic range of motion difference between left and right lower limbs, however, no previous study focused this difference in non-professional ballet dancers. In this study we aimed to evaluate active movements of the hip in non-professional classical dancers. Methods We evaluated 10 non professional ballet dancers (16-23 years old. We measured the active range of motion and flexibility through Well Banks. We compared active range of motion between left and right sides (hip flexion and abduction and performed correlation between active movements and flexibility. Results There was a small difference between the right and left sides of the hip in relation to the movements of flexion and abduction, which suggest the dominant side of the subjects, however, there was no statistical significance. Bank of Wells test revealed statistical difference only between the 1st and the 3rd measurement. There was no correlation between the movements of the hip (abduction and flexion, right and left sides with the three test measurements of the bank of Wells. Conclusion There is no imbalance between the sides of the hip with respect to active abduction and flexion movements in non-professional ballet dancers.

Evaluation of movements of lower limbs in non-professional ballet dancers: hip abduction and flexion

Science.gov (United States)

2011-01-01

Background The literature indicated that the majority of professional ballet dancers present static and active dynamic range of motion difference between left and right lower limbs, however, no previous study focused this difference in non-professional ballet dancers. In this study we aimed to evaluate active movements of the hip in non-professional classical dancers. Methods We evaluated 10 non professional ballet dancers (16-23 years old). We measured the active range of motion and flexibility through Well Banks. We compared active range of motion between left and right sides (hip flexion and abduction) and performed correlation between active movements and flexibility. Results There was a small difference between the right and left sides of the hip in relation to the movements of flexion and abduction, which suggest the dominant side of the subjects, however, there was no statistical significance. Bank of Wells test revealed statistical difference only between the 1st and the 3rd measurement. There was no correlation between the movements of the hip (abduction and flexion, right and left sides) with the three test measurements of the bank of Wells. Conclusion There is no imbalance between the sides of the hip with respect to active abduction and flexion movements in non-professional ballet dancers. PMID:21819566

Nociceptive flexion reflexes during analgesic neurostimulation in man.

Science.gov (United States)

García-Larrea, L; Sindou, M; Mauguière, F

1989-11-01

Nociceptive flexion reflexes of the lower limbs (RIII responses) have been studied in 21 patients undergoing either epidural (DCS, n = 16) or transcutaneous (TENS, n = 5) analgesic neurostimulation (AN) for chronic intractable pain. Flexion reflex RIII was depressed or suppressed by AN in 11 patients (52.4%), while no modification was observed in 9 cases and a paradoxical increase during AN was evidenced in 1 case. In all but 2 patients, RIII changes were rapidly reversible after AN interruption. RIII depression was significantly associated with subjective pain relief, as assessed by conventional self-rating; moreover, in 2 patients it was possible to ameliorate the pain-suppressing effects of AN by selecting those stimulation parameters (intensity and frequency) that maximally depressed nociceptive reflex RIII. We recorded 2 cases of RIII attenuation after contralateral neurostimulation. AN appeared to affect nociceptive reflexes rather selectively, with no or very little effect on other cutaneous, non-nociceptive responses. Recording of RIII reflexes is relatively simple to implement as a routine paraclinical procedure. It facilitates the objective assessment of AN efficacy and may help to choose the most appropriate parameters of neurostimulation. In addition, RIII behavior in patients could be relevant to the understanding of some of the mechanisms involved in AN-induced pain relief.

Theoretical study of a novel refrigeration compressor - Part II: Performance of a rotating discharge valve in the revolving vane (RV) compressor

Energy Technology Data Exchange (ETDEWEB)

Teh, Y.L.; Ooi, K.T. [Thermal and Fluids Engineering Division, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, S639798 (Singapore); Djamari, D. Wibowo [Engineering Mechanics Division, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, S639798 (Singapore)

2009-08-15

A new refrigeration compressor, named 'Revolving Vane (RV) compressor', has been introduced in Part I of this paper series. For a first time in refrigeration compressors, a rotating discharge valve is employed in the RV compressor mainly due to the rotation of the entire cylinder. This paper presents a theoretical investigation on the dynamic behavior of a reed-type discharge valve undergoing rotatory motion, with the primary objective of elucidating the applicability of such valves in refrigeration compressors. Under the application of the Euler-Bernoulli beam theory, a mathematical model of the rotating valve is formulated and the transient response of the valve under centrifugal loads in addition to pressure forces is analyzed. Results have shown that under careful design considerations, the performance as well as the reliability of the rotating discharge valve can be enhanced as compared to a non-rotating valve that has been used in all refrigeration compressors currently. (author)

The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve.

Science.gov (United States)

Baiget, Ernest; Corbi, Francisco; Fuentes, Juan Pedro; Fernández-Fernández, Jaime

2016-12-01

The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg) were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation). Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

Modification of Spastic Stretch Reflexes at the Elbow by Flexion Synergy Expression in Individuals With Chronic Hemiparetic Stroke.

Science.gov (United States)

McPherson, Jacob G; Stienen, Arno H; Drogos, Justin M; Dewald, Julius P

2018-03-01

To systematically characterize the effect of flexion synergy expression on the manifestation of elbow flexor stretch reflexes poststroke, and to relate these findings to elbow flexor stretch reflexes in individuals without neurologic injury. Controlled cohort study. Academic medical center. Participants (N=20) included individuals with chronic hemiparetic stroke (n=10) and a convenience sample of individuals without neurologic or musculoskeletal injury (n=10). Participants with stroke were interfaced with a robotic device that precisely manipulated flexion synergy expression (by regulating shoulder abduction loading) while delivering controlled elbow extension perturbations over a wide range of velocities. This device was also used to elicit elbow flexor stretch reflexes during volitional elbow flexor activation, both in the cohort of individuals with stroke and in a control cohort. In both cases, the amplitude of volitional elbow flexor preactivation was matched to that generated involuntarily during flexion synergy expression. The amplitude of short- and long-latency stretch reflexes in the biceps brachii, assessed by electromyography, and expressed as a function of background muscle activation and stretch velocity. Increased shoulder abduction loading potentiated elbow flexor stretch reflexes via flexion synergy expression in the paretic arm. Compared with stretch reflexes in individuals without neurologic injury, paretic reflexes were larger at rest but were approximately equal to control muscles at matched levels of preactivation. Because flexion synergy expression modifies stretch reflexes in involved muscles, interventions that reduce flexion synergy expression may confer the added benefit of reducing spasticity during functional use of the arm. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Are the Outcomes of Revision Knee Arthroplasty for Flexion Instability the Same as for Other Major Failure Mechanisms?

Science.gov (United States)

Rajgopal, Ashok; Panjwani, Taufiq R; Rao, Arun; Dahiya, Vivek

2017-10-01

Aseptic loosening, infection, and flexion instability have emerged as the leading etiologies for revision after total knee arthroplasty (TKA). Although studies have reported improved outcomes after revision TKA, the relative functional and clinical outcomes of patients revised for flexion instability and other failure etiologies have not been extensively reported. The aim of the study was to compare the functional and patient-reported outcomes of revision TKA for the common failure etiologies. We retrospectively reviewed records of 228 consecutive cases of revision TKA from 2008 to 2014. Revisions performed for aseptic loosening (n = 53), septic revisions (n = 48), and isolated flexion instability (n = 45) with a minimum of 18 months follow-up were included for analysis. Revision for all other etiologies (n = 82) were excluded. The Modified Knee Society Score (KSS), KSS Function, and Western Ontario and McMaster Universities Osteoarthritis Index were recorded for all cases. A 7-point Likert scale was used to record patient's perception of outcomes after revision surgery and analyzed based on etiology. Although all groups showed improvement in outcome after revision TKA, the changes in Modified KSS and KSS-Function varied according to the etiology of failure of the primary procedure with the smallest improvement being reported by the flexion instability group. Patients undergoing revision for isolated flexion instability have less improvement in functional outcome as compared with other etiologies. We hypothesize this is due to a higher baseline preoperative knee function in the flexion instability group. Copyright © 2017 Elsevier Inc. All rights reserved.

Structure of molecules and internal rotation

CERN Document Server

Mizushima, San-Ichiro

1954-01-01

Structure of Molecules and Internal Rotation reviews early studies on dihalogenoethanes. This book is organized into two parts encompassing 8 chapters that evaluate the Raman effect in ethane derivatives, the energy difference between rotational isomers, and the infrared absorption of ethane derivatives. Some of the topics covered in the book are the potential barrier to internal rotation; nature of the hindering potential; entropy difference between the rotational isomers; internal rotation in butane, pentane, and hexane; and internal rotation in long chain n-paraffins. Other chapters deal wi

Blood pressure and calf muscle oxygen extraction during plantar flexion exercise in peripheral artery disease.

Science.gov (United States)

Luck, J Carter; Miller, Amanda J; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D

2017-07-01

Peripheral artery disease (PAD) is an atherosclerotic vascular disease that affects 200 million people worldwide. Although PAD primarily affects large arteries, it is also associated with microvascular dysfunction, an exaggerated blood pressure (BP) response to exercise, and high cardiovascular mortality. We hypothesized that fatiguing plantar flexion exercise that evokes claudication elicits a greater reduction in skeletal muscle oxygenation (SmO 2 ) and a higher rise in BP in PAD compared with age-matched healthy subjects, but low-intensity steady-state plantar flexion elicits similar responses between groups. In the first experiment, eight patients with PAD and eight healthy controls performed fatiguing plantar flexion exercise (from 0.5 to 7 kg for up to 14 min). In the second experiment, seven patients with PAD and seven healthy controls performed low-intensity plantar flexion exercise (2.0 kg for 14 min). BP, heart rate (HR), and SmO 2 were measured continuously using near-infrared spectroscopy (NIRS). SmO 2 is the ratio of oxygenated hemoglobin to total hemoglobin, expressed as a percent. At fatigue, patients with PAD had a greater increase in mean arterial BP (18 ± 2 vs. vs. 10 ± 2 mmHg, P = 0.029) and HR (14 ± 2 vs. 6 ± 2 beats/min, P = 0.033) and a greater reduction in SmO 2 (-54 ± 10 vs. -12 ± 4%, P = 0.001). However, both groups had similar physiological responses to low-intensity, nonpainful plantar flexion exercise. These data suggest that patients with PAD have altered oxygen uptake and/or utilization during fatiguing exercise coincident with an augmented BP response. NEW & NOTEWORTHY In this laboratory study, patients with peripheral artery disease performed plantar flexion exercise in the supine posture until symptoms of claudication occurred. Relative to age- and sex-matched healthy subjects we found that patients had a higher blood pressure response, a higher heart rate response, and a greater reduction in skeletal muscle oxygenation as

Variability of Measurement of Patellofemoral Indices with Knee Flexion and Quadriceps Contraction: An MRI-Based Anatomical Study

Science.gov (United States)

Laugharne, Edward; Bali, Navi; Purushothamdas, Sanjay; Almallah, Faris; Kundra, Rik

2016-01-01

Purpose The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). Materials and Methods MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. Results With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction. PMID:27894177

Building utility executive strength. [Job rotation as part of management training

Energy Technology Data Exchange (ETDEWEB)

Esser, N.J.

1977-02-17

The selection and development of strong executive talent to manage the utility industry is essential if some of the controversy and confusion over the role and policies of utilities is to be resolved. The industry has traditionally trained and elevated executives within the organization, but new technical developments have changed the managerial skills required of executives. Today's manager needs an understanding of the total industry regardless of his initial training, the politics involved in advocating issues, and the need to keep costs down. To develop managerial continuity, utilities can institute job rotation as part of their management training program. The option to bring in executives from outside the company allows more stringent standards and introduces new ideas. Competitive salaries increase the opportunity to attract and retain talent. The Board of Directors can actively develop a flexible organizational structure that allows the executive group to adjust to changing demand. (DCK)

Treatable Bedridden Elderly―Recovery from Flexion Contracture after Cortisol Replacement in a Patient with Isolated Adrenocorticotropic Hormone Deficiency

Science.gov (United States)

Tanaka, Takamasa; Terada, Norihiko; Fujikawa, Yoshiki; Fujimoto, Takushi

2016-01-01

Isolated adrenocorticotropic hormone deficiency (IAD) is a rare disorder with diverse clinical presentations. A 79-year-old man was bedridden for six months due to flexion contractures of the bilateral hips and knees, along with hyponatremia. He was diagnosed with IAD based on the results of endocrine tests. After one month of corticosteroid replacement, he recovered and was able to stand up by himself. Although flexion contracture is a rare symptom of IAD, steroid replacement therapy may be effective, even for seemingly irreversibly bedridden elderly patients. In bedridden elderly patients with flexion contractures, we should consider and look for any signs of adrenal insufficiency. PMID:27746435

Treatable Bedridden Elderly -Recovery from Flexion Contracture after Cortisol Replacement in a Patient with Isolated Adrenocorticotropic Hormone Deficiency.

Science.gov (United States)

Tanaka, Takamasa; Terada, Norihiko; Fujikawa, Yoshiki; Fujimoto, Takushi

Isolated adrenocorticotropic hormone deficiency (IAD) is a rare disorder with diverse clinical presentations. A 79-year-old man was bedridden for six months due to flexion contractures of the bilateral hips and knees, along with hyponatremia. He was diagnosed with IAD based on the results of endocrine tests. After one month of corticosteroid replacement, he recovered and was able to stand up by himself. Although flexion contracture is a rare symptom of IAD, steroid replacement therapy may be effective, even for seemingly irreversibly bedridden elderly patients. In bedridden elderly patients with flexion contractures, we should consider and look for any signs of adrenal insufficiency.

Experimental occlusal interferences. Part IV. Mandibular rotations induced by a pliable interference.

Science.gov (United States)

Christensen, L V; Rassouli, N M

1995-11-01

In 12 subjects, a pliable, yet unbreakable, intercuspal interference (aluminum shim onlay splint; uniform height of 0.25 mm) was placed between either the right or left maxillary and mandibular second premolars and first molars. During brief and forceful biting (dynamic chewing stroke of about 20 kg force) the interference emulated a semisoft food bolus, and at the end of biting (subsequent static clenching stroke of about 20 kg force) it emulated a rigid metal interference. During dynamic/static biting, rotational electrognathography measured maximum frontal and horizontal plane torque of the right and left mandibular condyles. Eleven subjects (92%) showed frontal plane upward rotation (mean of 1.0 degree) of the condyle contralateral to the interference, and one subject (8%) showed frontal plane upward rotation (0.4 degree) of the condyle ipsilateral to the interference. Two subjects (17%) showed no horizontal plane rotation; seven subjects (58%) showed backward rotation (mean of 0.4 degree) of the condyle contralateral to the interference; and three subjects (25%) showed backward rotation (mean of 0.3 degree) of the condyle ipsilateral to the interference. It is suggested that, in the presence of an occlusal interference, mastication may have both short- and long-term detrimental effects.

Biceps Tendon Lengthening Surgery for Failed Serial Casting Patients With Elbow Flexion Contractures Following Brachial Plexus Birth Injury.

Science.gov (United States)

Nath, Rahul K; Somasundaram, Chandra

2016-01-01

Assessment of surgical outcomes of biceps tendon lengthening (BTL) surgery in obstetric brachial plexus injury (OBPI) patients with elbow flexion contractures, who had unsuccessful serial casting. Serial casting and splinting have been shown to be effective in correcting elbow flexion contractures in OBPI. However, the possibilities of radial head dislocations and other complications have been reported in serial casting and splinting. Literature indicates surgical intervention when such nonoperative techniques and range-of-motion exercises fail. Here, we demonstrated a significant reduction of the contractures of the affected elbow and improvement in arm length to more normal after BTL in these patients, who had unsuccessful serial casting. Ten OBPI patients (6 girls and 4 boys) with an average age of 11.2 years (4-17.7 years) had BTL surgery after unsuccessful serial casting. Mean elbow flexion contracture was 40° before and 37° (average) after serial casting. Mean elbow flexion contracture was reduced to 8° (0°-20°) post-BTL surgical procedure with an average follow-up of 11 months. This was 75% improvement and statistically significant (P casting. These OBPI patients in our study had 75% significant reduction in elbow flexion contractures and achieved an improved and more normal length of the affected arm after the BTL surgery when compared to only 7% insignificant reduction and no improvement in arm length after serial casting.

Motor Processes in Children's Mental Rotation

Science.gov (United States)

Frick, Andrea; Daum, Moritz M.; Walser, Simone; Mast, Fred W.

2009-01-01

Previous studies with adult human participants revealed that motor activities can influence mental rotation of body parts and abstract shapes. In this study, we investigated the influence of a rotational hand movement on mental rotation performance from a developmental perspective. Children at the age of 5, 8, and 11 years and adults performed a…

Development of a Robotic Assembly for Analyzing the Instantaneous Axis of Rotation of the Foot Ankle Complex

Directory of Open Access Journals (Sweden)

Kelly N. Salb

2016-01-01

Full Text Available Ankle instantaneous axis of rotation (IAR measurements represent a more complete parameter for characterizing joint motion. However, few studies have implemented this measurement to study normal, injured, or pathological foot ankle biomechanics. A novel testing protocol was developed to simulate aspects of in vivo foot ankle mechanics during mid-stance gait in a human cadaveric specimen. A lower leg was mounted in a robotic testing platform with the tibia upright and foot flat on the baseplate. Axial tibia loads (ATLs were controlled as a function of a vertical ground reaction force (vGRF set at half body weight (356 N and a 50% vGRF (178 N Achilles tendon load. Two specimens were repetitively loaded over 10 degrees of dorsiflexion and 20 degrees of plantar flexion. Platform axes were controlled within 2 microns and 0.008 degrees resulting in ATL measurements within ±2 N of target conditions. Mean ATLs and IAR values were not significantly different between cycles of motion, but IAR values were significantly different between dorsiflexion and plantar flexion. A linear regression analysis showed no significant differences between slopes of plantar flexion paths. The customized robotic platform and advanced testing protocol produced repeatable and accurate measurements of the IAR, useful for assessing foot ankle biomechanics under different loading scenarios and foot conditions.

Bilateral Distal Femoral Flexion Deformity After Total Knee Arthroplasty in a Patient with Rheumatoid Arthritis

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Jimmy Chan Chun-Ming

2013-12-01

Full Text Available Rheumatoid arthritis is an autoimmune systemic disease with predominant peripheral polyarthritis, often leading to severe joint destruction. This is a case report of an 81-year-old woman with long-standing severe rheumatoid arthritis requiring multiple orthopaedic operations for joint destruction since 2000. These operated joints improved her functional mobility until recently, when she found that her knees were fixed at around 70° of flexion with limited motion. There was chronic progressive flexion deformity of bilateral distal femurs, which was an extremely rare complication of total knee arthroplasty.

Femoral loosening of high-flexion total knee arthroplasty: The effect of posterior cruciate ligament retention and bone quality reduction

NARCIS (Netherlands)

Zelle, J.; van de Groes, S.A.W.; De Waal Malefijt, M.C.; Verdonschot, Nicolaas Jacobus Joseph

2014-01-01

High-flexion total knee arthroplasty (TKA) may be more sensitive to femoral loosening than conventional TKA as the knee joint force increases during deep flexion. The objective of this study was to evaluate whether the probability of femoral loosening is equal in posterior cruciate ligament (PCL)

Mental rotation and working memory in musicians' dystonia.

Science.gov (United States)

Erro, Roberto; Hirschbichler, Stephanie T; Ricciardi, Lucia; Ryterska, Agata; Antelmi, Elena; Ganos, Christos; Cordivari, Carla; Tinazzi, Michele; Edwards, Mark J; Bhatia, Kailash P

2016-11-01

Mental rotation of body parts engages cortical-subcortical areas that are actually involved in the execution of a movement. Musicians' dystonia is a type of focal hand dystonia that is grouped together with writer's cramp under the rubric of "occupational dystonia", but it is unclear to which extent these two disorders share common pathophysiological mechanisms. Previous research has demonstrated patients with writer's cramp to have deficits in mental rotation of body parts. It is unknown whether patients with musicians' dystonia would display similar deficits, reinforcing the concept of shared pathophysiology. Eight patients with musicians' dystonia and eight healthy musicians matched for age, gender and musical education, performed a number of tasks assessing mental rotation of body parts and objects as well as verbal and spatial working memories abilities. There were no differences between patients and healthy musicians as to accuracy and reaction times in any of the tasks. Patients with musicians' dystonia have intact abilities in mentally rotating body parts, suggesting that this disorder relies on a highly selective disruption of movement planning and execution that manifests only upon playing a specific instrument. We further demonstrated that mental rotation of body parts and objects engages, at least partially, different cognitive networks. Copyright © 2016 Elsevier Inc. All rights reserved.

Serial casting versus stretching technique to treat knee flexion contracture in children with spina bifida: a comparative study.

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Al-Oraibi, S; Tariah, Hashem Abu; Alanazi, Abdullah

2013-01-01

Severe knee contractures that develop soon after muscle imbalance may not improve with stretching exercises and splinting. An alternative treatment is serial casting, which has been used to promote increased range of motion. The purpose of this study was to compare the effectiveness of using serial casting and passive stretching approaches to treat knee flexion contracture in children with spina bifida. In a pre/post randomized controlled study, ten participants were included in the serial casting group, while eight participants were included in the passive stretching intervention group. The degree of knee extension was measured at baseline, immediately after intervention, and at a one-year follow-up using a standard goniometer. Both groups showed significant improvements in the degree of flexion contracture at the post-treatment evaluation and the follow-up evaluation. The serial casting group showed significant improvements in knee flexion contracture at the post-treatment evaluation, t (9)=13.4, p casting group compared with passive stretching group in relation to the degree of flexion contracture were found at the immediate post-treatment evaluation, F(1, 15)=246, p=0.0001, and the one-year follow-up evaluation, F (1, 15)=51.5, p=0.0001. The outcomes of this study provide the first evidence that serial casting may be a useful intervention in treating knee flexion contracture in children with spina bifida. However, further investigations into serial casting, as well as investigations into the use of serial casting with other interventions, are warranted.

Recovery of Muscle Strength After Intact Arthroscopic Rotator Cuff Repair According to Preoperative Rotator Cuff Tear Size.

Science.gov (United States)

Shin, Sang-Jin; Chung, Jaeyoon; Lee, Juyeob; Ko, Young-Won

2016-04-01

The recovery of muscle strength after arthroscopic rotator cuff repair based on the preoperative tear size has not yet been well described. The purpose of this study was to evaluate the recovery period of muscle strength by a serial assessment of isometric strength after arthroscopic rotator cuff repair based on the preoperative tear size. The hypothesis was that muscle strength in patients with small and medium tears would recover faster than that in those with large-to-massive tears. Cohort study; Level of evidence, 3. A total of 164 patients who underwent arthroscopic rotator cuff repair were included. Isometric strength in forward flexion (FF), internal rotation (IR), and external rotation (ER) was evaluated preoperatively and at 6, 12, 18, and 24 months after surgery. Preoperative magnetic resonance imaging scans were assessed to evaluate the quality of the rotator cuff muscle, including fatty infiltration, occupation ratio, and tangent sign. Patient satisfaction as well as visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES), and Constant scores were assessed at every follow-up. Muscle strength demonstrated the slowest recovery in pain relief and the restoration of shoulder function. To reach the strength of the uninjured contralateral shoulder in all 3 planes of motion, recovery took 6 months in patients with small tears and 18 months in patients with medium tears. Patients with large-to-massive tears showed continuous improvement in strength up to 18 months; however, they did not reach the strength of the contralateral shoulder at final follow-up. At final follow-up, mean strength in FF, IR, and ER was 113.0%, 118.0%, and 112.6% of the contralateral shoulder in patients with small tears, respectively; 105.0%, 112.1%, and 102.6% in patients with medium tears, respectively; and 87.6%, 89.5%, and 85.2% in patients with large-to-massive tears, respectively. Muscle strength in any direction did not significantly correlate with

Analytical shear and flexion of Einasto dark matter haloes

OpenAIRE

Retana-Montenegro, E.; Frutos-Alfaro, F.; Baes, M.

2012-01-01

N-body simulations predict that dark matter haloes are described by specific density profiles on both galactic- and cluster-sized scales. Weak gravitational lensing through the measurements of their first and second order properties, shear and flexion, is a powerful observational tool for investigating the true shape of these profiles. One of the three-parameter density profiles recently favoured in the description of dark matter haloes is the Einasto profile. We present exact expressions for...

Internal rotation of the Sun

International Nuclear Information System (INIS)

Duvall, T.L. Jr.; Goode, P.R.; Gouch, D.O.

1984-01-01

The frequency difference between prograde and retrograde sectoral solar oscillations is analysed to determine the rotation rate of the solar interior, assuming no latitudinal dependence. Much of the solar interior rotates slightly less rapidly than the surface, while the innermost part apparently rotates more rapidly. The resulting solar gravitational quadrupole moment is J 2 = (1.7 +- 0.4) x 10 -7 and provides a negligible contribution to current planetary tests of Einstein's theory of general relativity. (author)

The Immediate Effect of Neuromuscular Joint Facilitation (NJF) Treatment on Electromechanical Reaction Times of Hip Flexion.

Science.gov (United States)

Huo, Ming; Wang, Hongzhao; Ge, Meng; Huang, Qiuchen; Li, Desheng; Maruyama, Hitoshi

2013-11-01

[Purpose] The aim of this study was to investigate the change in electromechanical reaction times (EMG-RT) of hip flexion of younger persons after neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 39 healthy young people, who were divided into two groups: a NJF group and a proprioceptive neuromuscular facilitation (PNF) group. The NJF group consisted of 16 subjects (7 males, 9 females), and the PNF group consisted of 23 subjects (10 males, 13 females). [Methods] Participants in the NJF group received NJF treatment. We measured the EMG-RT, the premotor time (PMT) and the motor time (MT) during hip flexion movement before and after the intervention in both groups. [Results] There were no significant differences among the results of the PNF group. For the NJF group, there were significant differences in PMT and EMG-RT after NJF treatment. [Conclusion] These results suggest that there is an immediate effect of NJF intervention on electromechanical reaction times of hip flexion.

Tactile cues can change movement: An example using tape to redistribute flexion from the lumbar spine to the hips and knees during lifting.

Science.gov (United States)

Pinto, Brendan L; Beaudette, Shawn M; Brown, Stephen H M

2018-05-14

Given the appropriate cues, kinematic factors associated with low back injury risk and pain, such as spine flexion, can be avoided. Recent research has demonstrated the potential for tactile sensory information to change movement. In this study an athletic strapping tape was applied bilaterally along the lumbar extensor muscles to provide continuous tactile feedback information during a repeated lifting and lowering task. The presence of the tape resulted in a statistically significant reduction in lumbar spine flexion when compared to a baseline condition in which no tape was present. This reduction was further increased with the explicit instruction to pay attention to the sensations elicited by the tape. In both cases, the reduction in lumbar spine flexion was compensated for by increases in hip and knee flexion. When the tape was then removed and participants were instructed to continue lifting as if it was still present, the reduction in lumbar flexion and increases in hip and knee flexion were retained. Thus this study provides evidence that tactile cues can provide vital feedback information that can cue human lumbar spine movement to reduce kinematic factors associated with injury risk and pain. Copyright © 2018 Elsevier B.V. All rights reserved.

Outcome and Structural Integrity of Rotator Cuff after Arthroscopic Treatment of Large and Massive Tears with Double Row Technique: A 2-Year Followup

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Ignacio Carbonel

2013-01-01

Full Text Available Purpose. The purpose of this study was to evaluate the functional outcome and the tendon healing after arthroscopic double row rotator cuff repair of large and massive rotator cuff tears. Methods. 82 patients with a full-thickness large and massive rotator cuff tear underwent arthroscopic repair with double row technique. Results were evaluated by use of the UCLA, ASES, and Constant questionnaires, the Shoulder Strength Index (SSI, and range of motion. Follow-up time was 2 years. Magnetic resonance imaging (MRI studies were performed on each shoulder preoperatively and 2 years after repair. Results. 100% of the patients were followed up. UCLA, ASES, and Constant questionnaires showed significant improvement compared with preoperatively (P<0.001. Range of motion and SSI in flexion, abduction, and internal and external rotation also showed significant improvement (P<0.001. MRI studies showed 24 cases of tear after repair (29%. Only 8 cases were a full-thickness tear. Conclusions. At two years of followup, in large and massive rotator cuff tears, an arthroscopic double row rotator cuff repair technique produces an excellent functional outcome and structural integrity.

A flexible wearable sensor for knee flexion assessment during gait.

Science.gov (United States)

Papi, Enrica; Bo, Yen Nee; McGregor, Alison H

2018-05-01

Gait analysis plays an important role in the diagnosis and management of patients with movement disorders but it is usually performed within a laboratory. Recently interest has shifted towards the possibility of conducting gait assessments in everyday environments thus facilitating long-term monitoring. This is possible by using wearable technologies rather than laboratory based equipment. This study aims to validate a novel wearable sensor system's ability to measure peak knee sagittal angles during gait. The proposed system comprises a flexible conductive polymer unit interfaced with a wireless acquisition node attached over the knee on a pair of leggings. Sixteen healthy volunteers participated to two gait assessments on separate occasions. Data was simultaneously collected from the novel sensor and a gold standard 10 camera motion capture system. The relationship between sensor signal and reference knee flexion angles was defined for each subject to allow the transformation of sensor voltage outputs to angular measures (degrees). The knee peak flexion angle from the sensor and reference system were compared by means of root mean square error (RMSE), absolute error, Bland-Altman plots and intra-class correlation coefficients (ICCs) to assess test-retest reliability. Comparisons of knee peak flexion angles calculated from the sensor and gold standard yielded an absolute error of 0.35(±2.9°) and RMSE of 1.2(±0.4)°. Good agreement was found between the two systems with the majority of data lying within the limits of agreement. The sensor demonstrated high test-retest reliability (ICCs>0.8). These results show the ability of the sensor to monitor knee peak sagittal angles with small margins of error and in agreement with the gold standard system. The sensor has potential to be used in clinical settings as a discreet, unobtrusive wearable device allowing for long-term gait analysis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Muscle changes in brachial plexus birth injury with elbow flexion contracture: an MRI study

Energy Technology Data Exchange (ETDEWEB)

Poeyhiae, Tiina H; Koivikko, Mika P; Lamminen, Antti E [University of Helsinki, Helsinki Medical Imaging Center, Helsinki (Finland); Peltonen, Jari I; Nietosvaara, A Y [Helsinki University Central Hospital, Hospital for Children and Adolescents, Helsinki (Finland); Kirjavainen, Mikko O [Helsinki University Central Hospital, Department of Orthopaedics and Traumatology, Helsinki (Finland)

2007-02-15

Muscle pathology of the arm and forearm in brachial plexus birth injury (BPBI) with elbow flexion contracture has not been evaluated with MRI. To determine whether limited range of motion of the elbow in BPBI is correlated with specific patterns of muscular pathology. For 15 BPBI patients, total active motion (TAM) of the elbow (extension-flexion) and the forearm (pronation-supination) were measured. MRI of the elbow joints and musculature allowed assessment of elbow congruency. Fatty infiltration and size reduction of the muscles were graded semiquantitatively. Mean TAM of the elbow was 113 (50 -140 ) and that of the forearm 91 (10 -165 ). The greater the size reduction of the brachioradialis muscle, the more diminished was elbow TAM. The more extensive the BPBI and muscle pathology of the pronator teres muscle, the more limited was the TAM of the forearm. Pathology of the supinator and brachialis muscles was evident in every patient. Extensive BPBI may result in marked limitation of TAM. Elbow flexion contracture seems to be caused mainly by brachialis muscle pathology. Prosupination of the forearm is better preserved when the pronator teres is not severely affected. MRI can reliably show the extent of muscle pathology in BPBI. (orig.)

Muscle changes in brachial plexus birth injury with elbow flexion contracture: an MRI study

International Nuclear Information System (INIS)

Poeyhiae, Tiina H.; Koivikko, Mika P.; Lamminen, Antti E.; Peltonen, Jari I.; Nietosvaara, A.Y.; Kirjavainen, Mikko O.

2007-01-01

Muscle pathology of the arm and forearm in brachial plexus birth injury (BPBI) with elbow flexion contracture has not been evaluated with MRI. To determine whether limited range of motion of the elbow in BPBI is correlated with specific patterns of muscular pathology. For 15 BPBI patients, total active motion (TAM) of the elbow (extension-flexion) and the forearm (pronation-supination) were measured. MRI of the elbow joints and musculature allowed assessment of elbow congruency. Fatty infiltration and size reduction of the muscles were graded semiquantitatively. Mean TAM of the elbow was 113 (50 -140 ) and that of the forearm 91 (10 -165 ). The greater the size reduction of the brachioradialis muscle, the more diminished was elbow TAM. The more extensive the BPBI and muscle pathology of the pronator teres muscle, the more limited was the TAM of the forearm. Pathology of the supinator and brachialis muscles was evident in every patient. Extensive BPBI may result in marked limitation of TAM. Elbow flexion contracture seems to be caused mainly by brachialis muscle pathology. Prosupination of the forearm is better preserved when the pronator teres is not severely affected. MRI can reliably show the extent of muscle pathology in BPBI. (orig.)

Measurement properties of the craniocervical flexion test: a systematic review protocol.

Science.gov (United States)

Araujo, Francisco Xavier de; Ferreira, Giovanni Esteves; Scholl Schell, Maurício; Castro, Marcelo Peduzzi de; Silva, Marcelo Faria; Ribeiro, Daniel Cury

2018-02-22

Neck pain is the leading cause of years lived with disability worldwide and it accounts for high economic and societal burden. Altered activation of the neck muscles is a common musculoskeletal impairment presented by patients with neck pain. The craniocervical flexion test with pressure biofeedback unit has been widely used in clinical practice to assess function of deep neck flexor muscles. This systematic review will assess the measurement properties of the craniocervical flexion test for assessing deep cervical flexor muscles. This is a protocol for a systematic review that will follow the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. MEDLINE (via PubMed), EMBASE, PEDro, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus and Science Direct will be systematically searched from inception. Studies of any design that have investigated and reported at least one measurement property of the craniocervical flexion test for assessing the deep cervical flexor muscles will be included. All measurement properties will be considered as outcomes. Two reviewers will independently rate the risk of bias of individual studies using the updated COnsensus-based Standards for the selection of health Measurement Instruments risk of bias checklist. A structured narrative synthesis will be used for data analysis. Quantitative findings for each measurement property will be summarised. The overall rating for a measurement property will be classified as 'positive', 'indeterminate' or 'negative'. The overall rating will be accompanied with a level of evidence. Ethical approval and patient consent are not required since this is a systematic review based on published studies. Findings will be submitted to a peer-reviewed journal for publication. CRD42017062175. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Velocity of lordosis angle during spinal flexion and extension.

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Tobias Consmüller

Full Text Available The importance of functional parameters for evaluating the severity of low back pain is gaining clinical recognition, with evidence suggesting that the angular velocity of lordosis is critical for identification of musculoskeletal deficits. However, there is a lack of data regarding the range of functional kinematics (RoKs, particularly which include the changing shape and curvature of the spine. We address this deficit by characterising the angular velocity of lordosis throughout the thoracolumbar spine according to age and gender. The velocity of lumbar back shape changes was measured using Epionics SPINE during maximum flexion and extension activities in 429 asymptomatic volunteers. The difference between maximum positive and negative velocities represented the RoKs. The mean RoKs for flexion decreased with age; 114°/s (20-35 years, 100°/s (36-50 years and 83°/s (51-75 years. For extension, the corresponding mean RoKs were 73°/s, 57°/s and 47°/s. ANCOVA analyses revealed that age and gender had the largest influence on the RoKs (p<0.05. The Epionics SPINE system allows the rapid assessment of functional kinematics in the lumbar spine. The results of this study now serve as normative data for comparison to patients with spinal pathology or after surgical treatment.

Reliability of Measuring Lumbar Lordosis, Flexion and Extension Using Dual Inclinometer in Healthy Subjects and Patients with Non-Specific Chronic Low Back Pain

Directory of Open Access Journals (Sweden)

Samira Garmabi

2012-07-01

Full Text Available Objective: Accurate assessment of lumbar range of motion is of great value for both evaluating lumbar functions and monitoring treatment progress. Recent research indicates that there is no general consensus on the most valid and reliable method of measuring spinal range of motion. The purpose of this study was to determine the intra-rater reliability of lumbar flexion and extension measurements (within-day and between-days using the dual inclinometer technique.   Materials & Methods: Lumbar flexion and extension of 22 women (14 healthy and 8 with low back pain, were measured by the same examiner on three occasions. The first two measurements were taken with half an hour apart on the first occasion to assess the within-day reliability and the third measurement was taken one week later to assess the between-days reliability.  Results: Within-day lumbar lordosis, flexion and extension measurements using dual inclinometer technique were shown to be very reliable with high Intraclass Correlation Coefficients (ICC values (ICC were 98%, 77% and 69% for lordosis, flexion and extension measurements, respectively in healthy subjects and 94%, 95% and 69% for lordosis, flexion and extension measurements, respectively in patients group. Between-Days measurements also demonstrated high reliability with the high values of ICC (ICC were 96%, 70% and 67% for lordosis, flexion and extension measurements, in healthy subjects and 91%, 71% and 66% for lordosis, flexion and extension measurements, respectively in patients group. Conclusion: The results indicated that, the dual inclinometer technique appears to be a highly reliable method for measuring lumbar lordosis, flexion and extension and can be used as a reliable tool in the assessment of lumbar range of motion and monitoring therapeutic interventions.

Experimental occlusal interferences. Part III. Mandibular rotations induced by a rigid interference.

Science.gov (United States)

Rassouli, N M; Christensen, L V

1995-10-01

A rigid intercuspal interference (minimum mean height of 0.24 mm) was placed on either the right or left mandibular second premolar and first molar of 12 subjects. During brisk and forceful biting on the interference, rotational electrognathography measured maximum torque of the right and left mandibular condyles in the frontal and horizontal planes of orientation. All subjects showed frontal plan upward rotation (mean of 0.7 degrees) of the mandibular condyle contralateral to the interference. In 33% of the subjects there was no horizontal plane backward rotation. In 58% of the subjects there was horizontal plane backward rotation (mean of 0.5 degrees) of the mandibular condyle ipsilateral to the interference, and in one subject (8%) there was backward horizontal plane rotation (0.1 degree) of the mandibular condyle contralateral to the interference. It was inferred that the masseter muscle, ipsilateral to the interference, generated negative work in order to decelerate frontal plane 'unseating' of the mandibular condyle ipsilateral to the interference. It was inferred that the masseter muscle, contralateral to the interference, produced positive work in order to accelerate frontal plane 'seating' of the mandibular condyle contralateral to the interference. Finally, it was speculated that the impact forces of frontal plane 'seating' of the mandibular condyle, contralateral to the interference, might lead to 'vacuum sticking' of the temporomandibular joint disc because of the formation of negative hydrostatic pressures.

Reciprocal activation of gastrocnemius and soleus motor units is associated with fascicle length change during knee flexion.

Science.gov (United States)

Lauber, Benedikt; Lichtwark, Glen A; Cresswell, Andrew G

2014-06-01

While medial gastrocnemius (MG) and soleus (SOL) are considered synergists, they are anatomically exclusive in that SOL crosses only the ankle, while MG crosses both the knee and ankle. Due to the force-length properties of both active and passive structures, activation of SOL and MG must be constantly regulated to provide the required joint torques for any planned movement. As such, the aim of this study was to investigate the neural regulation of MG and SOL when independently changing their length by changing only the knee joint angle, thus exclusively altering the length of MG fibers. MG and SOL motor units (MU) were recorded intramuscularly along with ultrasound imaging of MG and SOL fascicle lengths, while moving the knee through 60° of rotation and maintaining a low level of voluntary plantar flexor torque. The results showed a reciprocal activation of MG and SOL as the knee was moved into flexion and extension. A clear reduction in MG MU firing rates occurred as the knee was flexed (MG fascicles shortening), with de-recruitment of most MG MU occurring at close to full knee flexion. A concomitant increase in SOL MU activity was observed while no change in the length of its fascicles was found. The opposite effects were found when the knee was moved into extension. A strong correlation (ICC = 0.78) was found between the fascicle length at which MG MUs were de-recruited and subsequently re-recruited. This was stronger than the relationship of de-recruitment and re-recruitment with knee angle (ICC = 0.52), indicating that in this instance, muscle fascicle length rather than joint angle is more influential in regulating MG recruitment. Such a reciprocal arrangement like the one presented here for SOL and MG is essential for human voluntary movements such as walking or cycling. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Distal nerve transfer versus supraclavicular nerve grafting: comparison of elbow flexion outcome in neonatal brachial plexus palsy with C5-C7 involvement.

Science.gov (United States)

Heise, Carlos O; Siqueira, Mario G; Martins, Roberto S; Foroni, Luciano H; Sterman-Neto, Hugo

2017-09-01

Ulnar and median nerve transfers to arm muscles have been used to recover elbow flexion in infants with neonatal brachial plexus palsy, but there is no direct outcome comparison with the classical supraclavicular nerve grafting approach. We retrospectively analyzed patients with C5-C7 neonatal brachial plexus palsy submitted to nerve surgery and recorded elbow flexion recovery using the active movement scale (0-7) at 12 and 24 months after surgery. We compared 13 patients submitted to supraclavicular nerve grafting with 21 patients submitted to distal ulnar or median nerve transfer to biceps motor branch. We considered elbow flexion scores of 6 or 7 as good results. The mean elbow flexion score and the proportion of good results were better using distal nerve transfers than supraclavicular grafting at 12 months (p nerve grafting at 12 months showed good elbow flexion recovery after ulnar nerve transfers. Distal nerve transfers provided faster elbow flexion recovery than supraclavicular nerve grafting, but there was no significant difference in the outcome after 24 months of surgery. Patients with failed supraclavicular grafting operated early can still benefit from late distal nerve transfers. Supraclavicular nerve grafting should remain as the first line surgical treatment for children with neonatal brachial plexus palsy.

A self-calibration method in single-axis rotational inertial navigation system with rotating mechanism

Science.gov (United States)

Chen, Yuanpei; Wang, Lingcao; Li, Kui

2017-10-01

Rotary inertial navigation modulation mechanism can greatly improve the inertial navigation system (INS) accuracy through the rotation. Based on the single-axis rotational inertial navigation system (RINS), a self-calibration method is put forward. The whole system is applied with the rotation modulation technique so that whole inertial measurement unit (IMU) of system can rotate around the motor shaft without any external input. In the process of modulation, some important errors can be decoupled. Coupled with the initial position information and attitude information of the system as the reference, the velocity errors and attitude errors in the rotation are used as measurement to perform Kalman filtering to estimate part of important errors of the system after which the errors can be compensated into the system. The simulation results show that the method can complete the self-calibration of the single-axis RINS in 15 minutes and estimate gyro drifts of three-axis, the installation error angle of the IMU and the scale factor error of the gyro on z-axis. The calibration accuracy of optic gyro drifts could be about 0.003°/h (1σ) as well as the scale factor error could be about 1 parts per million (1σ). The errors estimate reaches the system requirements which can effectively improve the longtime navigation accuracy of the vehicle or the boat.

Comparison of cranio-cervical flexion training versus cervical proprioception training in patients with chronic neck pain: A randomized controlled clinical trial.

Science.gov (United States)

Gallego Izquierdo, Tomás; Pecos-Martin, Daniel; Lluch Girbés, Enrique; Plaza-Manzano, Gustavo; Rodríguez Caldentey, Ricardo; Mayor Melús, Rodrigo; Blanco Mariscal, Diego; Falla, Deborah

2016-01-01

To compare the effects of cranio-cervical flexion vs cervical proprioception training on neuromuscular control, pressure pain sensitivity and perceived pain and disability in patients with chronic neck pain. Twenty-eight volunteers with chronic non-specific neck pain were randomly assigned to 1 of 2 interventions and undertook 6 physiotherapist-supervised sessions over a period of 2 months. Both groups performed daily home exercise. Performance on the cranio-cervical flexion test, pressure pain thresholds and reported levels of pain and disability were measured before and immediately after the first treatment session, 1 month after starting treatment and 2 months after starting treatment (at completion of the intervention). At 2 months, both groups improved their performance on the cranio-cervical flexion test (p  0.05). Both groups showed a reduction in their pain at rest and disability at 2 months, but this was also not different between groups (p > 0.05). Pressure pain sensitivity did not change for either group. Both specific cranio-cervical flexion training and proprioception training had a comparable effect on performance on the cranio-cervical flexion test, a test of the neuromuscular control of the deep cervical flexors. These results indicate that proprioception training may have positive effects on the function of the deep cervical flexors.

Are professional handball players at risk for developing a glenohumeral internal rotation deficit in their dominant arm?

Science.gov (United States)

Seabra, Pedro; Van Eck, Carola F; Sá, Márcia; Torres, João

2017-05-01

Overhead athletes, such as baseball players, have been shown to have adaptive changes in the shoulder range of motion (ROM) of their dominant arm. Professional handball players are a unique subtype of overhead athletes with very different demands from baseball players. The aim of this study was to determine if professional handball players demonstrate differences in shoulder ROM between their dominant and non-dominant arm and try to relate them with new variables. Fifty professional male handball players were included and completed a questionnaire regarding age at which they started to play, number of hours they practice a week, field position and arm dominance. ROM measurements were performed including forward flexion (FF), external rotation with the shoulder in abduction (ABER) and with adducted arm (ADER) and internal rotation with shoulder in abduction (IR). Statistical analysis was performed to determine differences in ROM between the dominant and non-dominant shoulder and if there is a relationship between these differences and shoulder load or field position. The dominant arm showed decreased internal rotation (47 vs. 56 degrees, p handball players with a first line position have a significant risk for developing a glenohumeral internal rotation deficit, similar to the phenomenon seen in baseball pitchers.

Reproducibility of joint space width and the intermargin distance measurements in patients with medial osteoarthritis of the knee in various degrees of flexion

International Nuclear Information System (INIS)

Takahashi, Toshiaki; Yamamoto, Haruyasu; Yamanaka, Norio; Ikeuchi, Masahiko

2009-01-01

This study tested the variability and reproducibility of measurements of the joint space width (JSW) and intermargin distance (IMD) of the medial tibial plateau in specific positions of knee flexion in osteoarthritic knees in order to evaluate the most useful knee angle for radiographic measurements. Radiographs from 56 knees with osteoarthritis from 46 patients were taken with the knees in conventional full extension and 15 , 30 , and 45 of flexion with weight bearing. Three orthopedic surgeons independently measured the JSW and IMD at the narrowest point and the midpoint of medial tibial plateau using a computer-assisted method. The JSW and IMD were smallest at 15 flexion, both measured at the narrowest point and the midpoint of the medial compartment. Reproducibility of the IMD at the midpoint was better than at the narrowest point for all four flexion angles. Measurements of the medial JSW and IMD are smallest at 15 of knee flexion indicating that radiographs should be obtained at this angle in order to best demonstrate the extent of osteoarthritis. (orig.)

Reproducibility of joint space width and the intermargin distance measurements in patients with medial osteoarthritis of the knee in various degrees of flexion

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Toshiaki; Yamamoto, Haruyasu [Ehime University Graduate School of Medicine, Department of Bone and Joint Surgery, Toon, Ehime (Japan); Yamanaka, Norio; Ikeuchi, Masahiko [Kochi University, Department of Orthopaedics, Kochi Medical School, Nankoku, Kochi (Japan)

2009-01-15

This study tested the variability and reproducibility of measurements of the joint space width (JSW) and intermargin distance (IMD) of the medial tibial plateau in specific positions of knee flexion in osteoarthritic knees in order to evaluate the most useful knee angle for radiographic measurements. Radiographs from 56 knees with osteoarthritis from 46 patients were taken with the knees in conventional full extension and 15 , 30 , and 45 of flexion with weight bearing. Three orthopedic surgeons independently measured the JSW and IMD at the narrowest point and the midpoint of medial tibial plateau using a computer-assisted method. The JSW and IMD were smallest at 15 flexion, both measured at the narrowest point and the midpoint of the medial compartment. Reproducibility of the IMD at the midpoint was better than at the narrowest point for all four flexion angles. Measurements of the medial JSW and IMD are smallest at 15 of knee flexion indicating that radiographs should be obtained at this angle in order to best demonstrate the extent of osteoarthritis. (orig.)

Relaxation processes in rotational motion

International Nuclear Information System (INIS)

Broglia, R.A.

1986-01-01

At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

Advances in Rotational Seismic Measurements

Energy Technology Data Exchange (ETDEWEB)

Pierson, Robert [Applied Technology Associates, Albuquerque, NM (United States); Laughlin, Darren [Applied Technology Associates, Albuquerque, NM (United States); Brune, Robert [Applied Technology Associates, Albuquerque, NM (United States)

2016-10-19

Rotational motion is increasingly understood to be a significant part of seismic wave motion. Rotations can be important in earthquake strong motion and in Induced Seismicity Monitoring. Rotational seismic data can also enable shear selectivity and improve wavefield sampling for vertical geophones in 3D surveys, among other applications. However, sensor technology has been a limiting factor to date. The US Department of Energy (DOE) and Applied Technology Associates (ATA) are funding a multi-year project that is now entering Phase 2 to develop and deploy a new generation of rotational sensors for validation of rotational seismic applications. Initial focus is on induced seismicity monitoring, particularly for Enhanced Geothermal Systems (EGS) with fracturing. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, improved noise floors, robustness, and repeatability. This paper presents a summary of Phase 1 results and Phase 2 status.

Normal postural responses preceding shoulder flexion: co-activation or asymmetric activation of transverse abdominis?

Science.gov (United States)

Davarian, Sanaz; Maroufi, Nader; Ebrahimi, Esmaeil; Parnianpour, Mohammad; Farahmand, Farzam

2014-01-01

It is suggested that activation of the transverse abdominis muscle has a stabilizing effect on the lumbar spine by raising intra-abdominal pressure without added disc compression. However, its feedforward activity has remained a controversial issue. In addition, research regarding bilateral activation of trunk muscles during a unilateral arm movement is limited. The aim of this study was to evaluate bilateral anticipatory activity of trunk muscles during unilateral arm flexion. Eighteen healthy subjects (aged 25 ± 3.96 years) participated in this study and performed 10 trials of rapid arm flexion in response to a visual stimulus. The electromyographic activity of the right anterior deltoid (AD) and bilateral trunk muscles including the transverse abdominis/internal oblique (TA/IO), superficial lumbar multifidus (SLM) and lumbar erector spine (LES) was recorded. The onset latency and anticipatory activity of the recorded trunk muscles were calculated. The first muscle activated in anticipation of the right arm flexion was the left TA/IO. The right TA/IO activated significantly later than all other trunk muscles (P 0.05). Healthy subjects showed no bilateral anticipatory co-activation of TA/IO in unilateral arm elevation. Further investigations are required to delineate normal muscle activation pattern in healthy subjects prior to prescribing bilateral activation training of transverse abdominis for subjects with chronic low back pain.

Medial Patellofemoral Ligament Reconstruction: Impact of Knee Flexion Angle During Graft Fixation on Dynamic Patellofemoral Contact Pressure-A Biomechanical Study.

Science.gov (United States)

Lorbach, Olaf; Zumbansen, Nikolaus; Kieb, Matthias; Efe, Turgay; Pizanis, Antonius; Kohn, Dieter; Haupert, Alexander

2018-04-01

Objective evaluation of the optimal graft tension angle to fully restore patellofemoral contact pressure in reconstruction of the medial patellofemoral ligament (MPFL) in comparison to the native knee. Twelve cadaveric knee specimens were fixed in a custom-made fixation device. A sensitive pressure film (Tekscan) was fixed in the patellofemoral joint, and patellofemoral contact pressure was assessed during a dynamic flexion movement from 0° to 90°. The MPFL was cut and measurements were repeated. Reconstruction of the MPFL was performed with the gracilis tendon subsequently fixed in the femur at 15°, 30°, 45°, 60°, 75°, and 90° of knee flexion under controlled tension (2 N). The sequence of the flexion angles was alternated. Pressure measurements were repeated after every fixation of the graft. No significant differences were seen in the overall patellofemoral contact pressure compared to the native knee (P > .05). However, medial patellofemoral pressure showed a significant increased patellofemoral contact pressure after MPFL reconstruction at a knee flexion angle during graft fixation of 15° (P = .027), 45° (P = .050, P = .044), and 75° (P = .039). Moreover, proximal/distal patellofemoral contact pressure revealed a significantly reduced contact pressure at 15° (P = .003), 30° (P = .009), 45° (P = .025), 75° (P = .021), and 90° (P = .022) of flexion distal after MPFL reconstruction compared with the intact knee. Lateral patellofemoral contact pressure was significantly reduced in all performed reconstructions (P angle during graft fixation for MPFL reconstruction did not have a significant impact on the overall patellofemoral contact pressure. However, selective medial, proximal, distal, and lateral patellofemoral contact pressure was significantly altered for all reconstructions. Fixation of the MPFL graft at 60° of flexion was able to most closely restore patellofemoral contact pressure compared with the intact knee. Based on the

Comparison of knee flexion isokinetic deficits between seated and prone positions after ACL reconstruction with hamstrings graft: Implications for rehabilitation and return to sports decisions.

Science.gov (United States)

Koutras, Georgios; Bernard, Manfred; Terzidis, Ioannis P; Papadopoulos, Pericles; Georgoulis, Anastasios; Pappas, Evangelos

2016-07-01

Hamstrings grafts are commonly used in ACL reconstruction, however, the effect of graft harvesting on knee flexion strength has not been longitudinally evaluated in functional positions. We hypothesized that greater deficits in knee flexion strength exist in the prone compared to the seated position and these deficits remain as rehabilitation progresses. Case series. Forty-two consecutive patients who underwent ACL reconstruction with a hamstrings graft were followed prospectively for 9 months. Isokinetic knee flexion strength at a slow and a fast speed were collected at 3, 4, 6, and 9 months in two different positions: conventional (seated) and functional (0° of hip flexion). Peak torque knee flexion deficits were higher in the prone position compared to the seated position by an average of 6.5% at 60°/s and 9.1% at 180°/s (p<0.001). Measuring knee flexion strength in prone demonstrates higher deficits than in the conventional seated position. Most athletes would not be cleared to return to sports even at 9 months after surgery with this method. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Unbalance influence on the rotating assembly dynamics of a hydro

Science.gov (United States)

Jurcu, M.; Pădureanu, I.; Campian, C. V.; Haţiegan, C.

2018-01-01

The dynamics of the rotating parts of a hydro is characterized by the dynamic interaction between the rotor, the stator and the working fluid in order to operate the hydro. The main factors influencing the dynamics of the rotating parts of a hydro are: rotor unbalance, unbalanced magnetic pull, shaft misalignment and hydraulic flow regime. Rotor unbalanced is one of the most common factors influencing the dynamic stability of the rotating parts of a hydro. The unbalanced is determined by: uneven distribution of rotating masses, displacement of parts in the rotor during rotation, inhomogeneity of rotor component materials, expansion of the rotor due to heating, and rising speed during the transient discharge of the load. The mechanical imbalance of a rotor can lead to important forces, responsible for the vibration of the machine, which ultimately leads to a shorter operating time. Even a low unbalance can lead, in the case of high speed machines, to major unbalance forces that cause significant damage to the equipment. The unbalance forces cause additional vibrations in the bearings as well as in the foundation plate. To avoid these vibrations, it is necessary in the first stage to balance the static rotor in the construction plant and then to a dynamic rotation balancing.

Progressive Abduction Loading Therapy with Horizontal-Plane Viscous Resistance Targeting Weakness and Flexion Synergy to Treat Upper Limb Function in Chronic Hemiparetic Stroke: A Randomized Clinical Trial.

Science.gov (United States)

Ellis, Michael D; Carmona, Carolina; Drogos, Justin; Dewald, Julius P A

2018-01-01

Progressive abduction loading therapy has emerged as a promising exercise therapy in stroke rehabilitation to systematically target the loss of independent joint control (flexion synergy) in individuals with chronic moderate/severe upper-extremity impairment. Preclinical investigations have identified abduction loading during reaching exercise as a key therapeutic factor to improve reaching function. An augmentative approach may be to additionally target weakness by incorporating resistance training to increase constitutive joint torques of reaching with the goal of improving reaching function by "overpowering" flexion synergy. The objective was, therefore, to determine the therapeutic effects of horizontal-plane viscous resistance in combination with progressive abduction loading therapy. 32 individuals with chronic hemiparetic stroke were randomly allocated to two groups. The two groups had equivalent baseline characteristics on all demographic and outcome metrics including age (59 ± 11 years), time poststroke (10.1 ± 7.6 years), and motor impairment (Fugl-Meyer, 26.7 ± 6.5 out of 66). Both groups received therapy three times/week for 8 weeks while the experimental group included additional horizontal-plane viscous resistance. Quantitative standardized progression of the intervention was achieved using a robotic device. The primary outcomes of reaching distance and velocity under maximum abduction loading and secondary outcomes of isometric strength and a clinical battery were measured at pre-, post-, and 3 months following therapy. There was no difference between groups on any outcome measure. However, for combined groups, there was a significant increase in reaching distance (13.2%, effect size; d  = 0.56) and velocity (13.6%, effect size; d  = 0.27) at posttesting that persisted for 3 months and also a significant increase in abduction, elbow extension, and external rotation strength at posttesting that did not persist 3�

Gravity currents in rotating channels. Part 1. Steady-state theory

Science.gov (United States)

Hacker, J. N.; Linden, P. F.

2002-04-01

A theory is developed for the speed and structure of steady-state non-dissipative gravity currents in rotating channels. The theory is an extension of that of Benjamin (1968) for non-rotating gravity currents, and in a similar way makes use of the steady-state and perfect-fluid (incompressible, inviscid and immiscible) approximations, and supposes the existence of a hydrostatic ‘control point’ in the current some distance away from the nose. The model allows for fully non-hydrostatic and ageostrophic motion in a control volume V ahead of the control point, with the solution being determined by the requirements, consistent with the perfect-fluid approximation, of energy and momentum conservation in V, as expressed by Bernoulli's theorem and a generalized flow-force balance. The governing parameter in the problem, which expresses the strength of the background rotation, is the ratio W = B/R, where B is the channel width and R = (g[prime prime or minute]H)1/2/f is the internal Rossby radius of deformation based on the total depth of the ambient fluid H. Analytic solutions are determined for the particular case of zero front-relative flow within the gravity current. For each value of W there is a unique non-dissipative two-layer solution, and a non-dissipative one-layer solution which is specified by the value of the wall-depth h0. In the two-layer case, the non-dimensional propagation speed c = cf(g[prime prime or minute]H)[minus sign]1/2 increases smoothly from the non-rotating value of 0.5 as W increases, asymptoting to unity for W [rightward arrow] [infty infinity]. The gravity current separates from the left-hand wall of the channel at W = 0.67 and thereafter has decreasing width. The depth of the current at the right-hand wall, h0, increases, reaching the full depth at W = 1.90, after which point the interface outcrops on both the upper and lower boundaries, with the distance over which the interface slopes being 0.881R. In the one-layer case, the wall

The role of rotational hand movements and general motor ability in children’s mental rotation performance

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Petra eJansen

2015-07-01

Full Text Available Mental rotation of visual images of body parts and abstract shapes can be influenced by simultaneous motor activity. Children in particular seem to have a strong coupling between motor and cognitive processes. We investigated the influence of a rotational hand movement performed by rotating a knob on mental rotation performance in primary school-age children (N= 83; Age range: 7.0-8.3 and 9.0-10.11 years. In addition, we assessed the role of motor ability in this relationship. Boys in the 7-8-year-old group were faster when mentally and manually rotating in the same direction than in the opposite direction. For girls and older children this effect was not found. A positive relationship was found between motor ability and accuracy on the mental rotation task: stronger motor ability related to improved mental rotation performance. In both age groups, children with more advanced motor abilities were more likely to adopt motor processes to solve mental rotation tasks if the mental rotation task was primed by a motor task. Our evidence supports the idea that an overlap between motor and visual cognitive processes in children is influenced by motor ability.

Posterior cruciate ligament recruitment affects antero-posterior translation during flexion gap distraction in total knee replacement. An intraoperative study involving 50 patients.

NARCIS (Netherlands)

Heesterbeek, P.J.C.; Keijsers, N.; Jacobs, W.; Verdonschot, N.J.J.; Wymenga, A.B.

2010-01-01

BACKGROUND AND PURPOSE: Because of the oblique orientation of the posterior cruciate ligament (PCL), flexion gap distraction could lead to anterior movement of the tibia, which would influence the tibiofemoral contact point. This would affect the kinematics of the TKR. We assessed the flexion gap

Pneumatic Multi-Pocket Elastomer Actuators for Metacarpophalangeal Joint Flexion and Abduction-Adduction

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Tapio Veli Juhani Tarvainen

2017-09-01

Full Text Available During recent years, interest has been rising towards developing fluidic fiber-reinforced elastomer actuators for wearable soft robotics used in hand rehabilitation and power-assist. However, they do not enable finger abduction-adduction, which plays an important role in activities of daily living, when grasping larger objects. Furthermore, the developed gloves often do not have separate control of joints, which is important for doing various common rehabilitation motions. The main obstacle for the development of a fully-assisting glove is moving a joint with multiple degrees of freedom. If the functions are built into the same structure, they are naturally coupled and affect each other, which makes them more difficult to design and complex to control than a simple flexion-extension actuator. In this study, we explored the key design elements and fabrication of pneumatic multi-pocket elastomer actuators for a soft rehabilitation glove. The goal was to gain more control over the metacarpophalangeal joint’s response by increasing the degree of actuation. Three main functional designs were tested for achieving both flexion and abduction-adduction. Five prototypes, with four different actuator geometries and four different reinforcement types, were designed and fabricated. They were evaluated by recording their free motion with motion capture and measuring their torque output using a dummy finger. Results showed the strengths and weaknesses of each design in separating the control of the two functions. We discuss the different improvements that are needed in order to make each design plausible for developing an actuator that meets the requirements for full assist of the hand’s motions. In conclusion, we show that it is possible to produce multi-pocket actuators for assisting MCP joint motion in both flexion and abduction-adduction, although coupling between the separate functions is still problematic and should be considered further.

Does an Injection of Adipose-Derived Mesenchymal Stem Cells Loaded in Fibrin Glue Influence Rotator Cuff Repair Outcomes? A Clinical and Magnetic Resonance Imaging Study.

Science.gov (United States)

Kim, Yong Sang; Sung, Chang Hun; Chung, Sung Hoon; Kwak, Sang Joon; Koh, Yong Gon

2017-07-01

The mesenchymal stem cell (MSC)-based tissue engineering approach has been developed to improve the treatment of rotator cuff tears. Hypothesis/Purpose: The purpose was to determine the effect of an injection of adipose-derived MSCs loaded in fibrin glue during arthroscopic rotator cuff repair on clinical outcomes and to evaluate its effect on structural integrity using magnetic resonance imaging (MRI). The hypothesis was that the application of adipose-derived MSCs would improve outcomes after the surgical repair of a rotator cuff tear. Cohort study; Level of evidence, 3. Among 182 patients treated with arthroscopic surgery for a rotator cuff tear, 35 patients treated with arthroscopic rotator cuff repair alone (conventional group) were matched with 35 patients who underwent arthroscopic rotator cuff repair with an injection of adipose-derived MSCs loaded in fibrin glue (injection group) based on sex, age, and lesion size. Outcomes were assessed with respect to the visual analog scale (VAS) for pain, range of motion (ROM) (including forward flexion, external rotation at the side, and internal rotation at the back), and functional measures of the Constant score and University of California, Los Angeles (UCLA) shoulder rating scale. Repaired tendon structural integrity was assessed by using MRI at a minimum of 12 months after surgery, and the mean clinical follow-up was 28.8 ± 4.2 months in the conventional group and 28.3 ± 3.8 months in the injection group. The mean VAS score at rest and during motion improved significantly in both groups after surgery. However, there were no significant differences between the groups at the final follow-up ( P = .256 and .776, respectively). Compared with preoperative measurements, forward flexion and external rotation at the side significantly improved at the final follow-up in both groups (all P rotation at the back were observed in either group ( P = .625 and .834 for the conventional and injection groups, respectively

Influence of lumbar curvature and rotation on forward flexibility in idiopathic scoliosis

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Feng-Chun Kao

2014-04-01

Full Text Available Background: Lumbar spine facet joints are arranged sagittally and mainly provide forward flexibility. Rotation of the lumbar vertebral body and coronal plane deformity may influence the function of lumbar forward flexibility. We hypothesize that the more advanced axial and coronal plane deformity could cause more limitation on forward flexibility in patients with idiopathic scoliosis. Methods: Between January 2011 and August 2011, 85 patients with adolescent idiopathic scoliosis were enrolled in this study. The proximal thoracic, major thoracic, thoracolumbar/lumbar (TL/L, and lumbar (L1/L5 curves were measured by Cobb's method. Lumbar apical rotation was graded using the Nash-Moe score. Lumbar forward flexibility was measured using the sit and reach (S and R test. Statistical analysis was performed using one-way analysis of variance (ANOVA, Spearman's and Pearson's correlation coefficients. Results: The mean age was 16.1 ± 2.84 years. The mean proximal thoracic, major thoracic, TL/L, and L1/L5 curves were 17.61° ± 8.92, 25.56° ± 11.61, 26.09° ± 8.6, and 15.10° ± 7.85, respectively. The mean S and R measurement was 25.56 ± 12.33 cm. The magnitude of the TL/L and L1/L5 curves was statistically positively related to vertebral rotation (rs = 0.580 and 0.649, respectively. The correlation between the S and R test and both the TL/L and L1/L5 curves was negative (rp = –0.371 and –0.595, respectively. Besides, the S and R test also demonstrated a significant negative relationship with vertebral rotation (rs = –0.768. Conclusion: In patients with idiopathic scoliosis, spinal deformity can diminish lumbar forward flexibility. Higher lumbar curvature and rotation lead to greater restriction of lumbar flexion.

Evaluation of the clinical-functional results from repairing extensive rotator cuff injury with inclusion of the tendon of the long head of the biceps

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Roberto Yukio Ikemoto

2013-04-01

Full Text Available OBJECTIVES: To assess the outcomes of the arthroscopic margin convergence of the posterior cuff to the biceps tendon. METHODS: From October 2003 to December 2007, 20 patients with massive rotator cuff tear which include the rotator interval were treated with arthroscopic margin convergence of the posterior cuff to biceps tendon. Sixteen patients were female and four were male. The mean age was 58.95 years old. The dominant side was affected in 16 cases (80%. The outcomes were analysed according to the UCLA Score with a minimum follow-up period of two years. RESULTS: The UCLA score improved, on average, 14 points (p < 0.001. Six patients had excellent results; nine good; three fair and two poor results. The mean improvement of forward flexion was 33º (p < 0.001, 3º of external rotation (p < 0.396 and two vertebral levels for internal rotation (p < 0.025. CONCLUSION: The arthroscopic margin convergence of the posterior cuff to the biceps tendon leads to satisfactory results.

Rotational foot placement specifies the lever arm of the ground reaction force during the push-off phase of walking initiation.

Science.gov (United States)

Erdemir, Ahmet; Piazza, Stephen J

2002-06-01

The lever arm of the ground reaction force (GRF) about the talocrural joint axis is a functionally important indicator of the nature of foot loading. Walking initiation experiments (ten subjects; age, 23-29 years) were completed to demonstrate that rotational foot placement is a possible strategy to specify the lever arm. Externally-rotated foot placement resulted in larger lever arms during push-off. A computer simulation of push-off revealed that a decreased lever arm reduces the plantarflexion moment necessary to maintain a constant forward velocity, while increasing the required plantarflexion velocity. Shortening of the foot thus diminishes the muscular force demand but also requires high muscle fiber shortening velocities that may limit the force generating capacity of plantar flexors. Decreased plantar flexion moment and slow walking previously noted in partial-foot amputees may result from shortened lever arms in this manner.

Segmental lumbar spine instability at flexion-extension radiography can be predicted by conventional radiography

Energy Technology Data Exchange (ETDEWEB)

Pitkaenen, M.T.; Manninen, H.I.; Lindgren, K.-A.J.; Sihvonen, T.A.; Airaksinen, O.; Soimakallio, S

2002-07-01

AIM: To identify plain radiographic findings that predict segmental lumbar spine instability as shown by functional flexion-extension radiography. MATERIALS AND METHODS: Plain radiographs and flexion-extension radiographs of 215 patients with clinically suspected lumbar spine instability were analysed. Instability was classified into anterior or posterior sliding instability. The registered plain radiographic findings were traction spur, spondylarthrosis, arthrosis of facet joints, disc degeneration, retrolisthesis, degenerative spondylolisthesis, spondylolytic spondylolisthesis and vacuum phenomena. Factors reaching statistical significance in univariate analyses (P < 0.05) were included in stepwise multiple logistic regression analysis. RESULTS: Degenerative spondylolisthesis (P = 0.004 at L3-4 level and P = 0.017 at L4-5 level in univariate analysis and odds ratio 16.92 at L4-5 level in multiple logistic regression analyses) and spondylolytic spondylolisthesis (P = 0.003 at L5-S1 level in univariate analyses) were the strongest independent determinants of anterior sliding instability. Retrolisthesis (odds ratio 10.97), traction spur (odds ratio 4.45) and spondylarthrosis (odds ratio 3.20) at L3-4 level were statistically significant determinants of posterior sliding instability in multivariate analysis. CONCLUSION: Sliding instability is strongly associated with various plain radiographic findings. In mechanical back pain, functional flexion-extension radiographs should be limited to situations when symptoms are not explained by findings of plain radiographs and/or when they are likely to alter therapy. Pitkaenen, M.T. et al. (2002)

Segmental lumbar spine instability at flexion-extension radiography can be predicted by conventional radiography

International Nuclear Information System (INIS)

Pitkaenen, M.T.; Manninen, H.I.; Lindgren, K.-A.J.; Sihvonen, T.A.; Airaksinen, O.; Soimakallio, S.

2002-01-01

AIM: To identify plain radiographic findings that predict segmental lumbar spine instability as shown by functional flexion-extension radiography. MATERIALS AND METHODS: Plain radiographs and flexion-extension radiographs of 215 patients with clinically suspected lumbar spine instability were analysed. Instability was classified into anterior or posterior sliding instability. The registered plain radiographic findings were traction spur, spondylarthrosis, arthrosis of facet joints, disc degeneration, retrolisthesis, degenerative spondylolisthesis, spondylolytic spondylolisthesis and vacuum phenomena. Factors reaching statistical significance in univariate analyses (P < 0.05) were included in stepwise multiple logistic regression analysis. RESULTS: Degenerative spondylolisthesis (P = 0.004 at L3-4 level and P = 0.017 at L4-5 level in univariate analysis and odds ratio 16.92 at L4-5 level in multiple logistic regression analyses) and spondylolytic spondylolisthesis (P = 0.003 at L5-S1 level in univariate analyses) were the strongest independent determinants of anterior sliding instability. Retrolisthesis (odds ratio 10.97), traction spur (odds ratio 4.45) and spondylarthrosis (odds ratio 3.20) at L3-4 level were statistically significant determinants of posterior sliding instability in multivariate analysis. CONCLUSION: Sliding instability is strongly associated with various plain radiographic findings. In mechanical back pain, functional flexion-extension radiographs should be limited to situations when symptoms are not explained by findings of plain radiographs and/or when they are likely to alter therapy. Pitkaenen, M.T. et al. (2002)

Fixed-flexion radiography of the knee provides reproducible joint space width measurements in osteoarthritis

International Nuclear Information System (INIS)

Kothari, Manish; Sieffert, Martine; Block, Jon E.; Peterfy, Charles G.; Guermazi, Ali; Ingersleben, Gabriele von; Miaux, Yves; Stevens, Randall

2004-01-01

The validity of a non-fluoroscopic fixed-flexion radiographic acquisition and analysis protocol for measurement of joint space width (JSW) in knee osteoarthritis is determined. A cross-sectional study of 165 patients with documented knee osteoarthritis participating in a multicenter, prospective study of chondroprotective agents was performed. All patients had posteroanterior, weight-bearing, fixed-flexion radiography with 10 caudal beam angulation. A specially designed frame (SynaFlexer) was used to standardize the positioning. Minimum medial and lateral JSW were measured manually and twice by an automated analysis system to determine inter-technique and intra-reader concordance and reliability. A random subsample of 30 patients had repeat knee radiographs 2 weeks apart to estimate short-term reproducibility using automated analysis. Concordance between manual and automated medial JSW measurements was high (ICC=0.90); lateral compartment measurements showed somewhat less concordance (ICC=0.72). There was excellent concordance between repeated automated JSW measurements performed 6 months apart for the medial (ICC=0.94) and lateral (ICC=0.86) compartments. Short-term reproducibility for the subsample of 30 cases with repeat acquisitions demonstrated an average SD of 0.14 mm for medial JSW (CV=4.3%) and 0.23 mm for lateral JSW (CV=4.0%). Fixed-flexion radiography of the knee using a positioning device provides consistent, reliable and reproducible measurement of minimum JSW in knee osteoarthritis without the need for concurrent fluoroscopic guidance. (orig.)

The effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine.

Science.gov (United States)

Sleutjens, J; Voorhout, G; Van Der Kolk, J H; Wijnberg, I D; Back, W

2010-11-01

In dressage, the head and neck position has become an issue of concern as certain extreme positions may imply a welfare risk for the horse. In man, extension and flexion of the cervical spine cause a decrease and increase in intervertebral foramina dimensions, respectively. However, in horses, the influence of flexion and extension on foramina dimensions and its possible interference with peripheral nerve functioning remains unknown. To determine the effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine. Computed tomography was performed on 6 cadaver cervical spines from adult Warmblood horses subjected to euthanasia for reasons unrelated to cervical spine abnormalities, in a neutral position, in 20 and 40° extension, and in 20 and 40° flexion. Multiplanar reconstructions were made to obtain transverse images perpendicular to the long axis of each pair of intervertebral foramina from C2-T1. Intervertebral foramina dimensions were measured in the 5 positions. Compared to the neutral position, 40° extension caused a decrease in foramina dimensions at segments C4-C5, C5-C6, C6-C7 (P dimensions at segments C5-C6 (P dimensions at segments C4-T1, similar to that found in man. In vivo extension of the cervical spine could possibly interfere with peripheral nerve functioning at segments C4-T1. This effect may be even more profound in patients with a reduced intervertebral foramina space, for example in the presence of facet joint arthrosis. © 2010 EVJ Ltd.

Comportement en flexion des bétons fibrés sous chargement cyclique

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Boulekbache Bensaid

2014-04-01

Full Text Available Ce papier présente les résultats d’une étude expérimentale sur le comportement en flexion des bétons de fibres métalliques. On étudie l’effet de la rhéologie du béton sur l’orientation des fibres et l’influence de l’orientation sur les propriétés mécaniques. La rigidité de l’ancrage des fibres étudiée par les essais cycliques est liée aux caractéristiques rhéologiques et mécaniques de la matrice. Les résultats montrent que la fluidité des bétons est un paramètre essentiel de l’orientation des fibres. Dès lors que l’on obtient une orientation dans le sens de l’efficacité mécanique, la résistance à la flexion est nettement améliorée.

Correlations of hip mobility with degree of back pain and lumbar spinal mobility in chronic low-back pain patients.

Science.gov (United States)

Mellin, G

1988-06-01

Mobility of hips and lumbar spine were measured in 301 men and 175 women who were in employment but suffered from chronic or recurrent low-back pain. The degree of low-back pain (LBP) was assessed with a questionnaire. Hip flexion, extension, internal rotation, and hamstring flexibility in the men, and hip flexion and extension in the women had statistically significant negative correlations with LBP. Among the correlations between hip and lumbar spinal mobility, hip flexion and extension with lumbar rotation were strongest.

PELVIC ROTATION AND LOWER EXTREMITY MOTION WITH TWO DIFFERENT FRONT FOOT DIRECTIONS IN THE TENNIS BACKHAND GROUNDSTROKE

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Sayumi Iwamoto

2013-06-01

Full Text Available When a tennis player steps forward to hit a backhand groundstroke in closed stance, modifying the direction of the front foot relative to the net may reduce the risk of ankle injury and increase performance. This study evaluated the relationship between pelvic rotation and lower extremity movement during the backhand groundstroke when players stepped with toes parallel to the net (Level or with toes pointed towards the net (Net. High school competitive tennis players (eleven males and seven females, 16.8 ± 0.8 years, all right- handed performed tennis court tests comprising five maximum speed directional runs to the court intersection line to hit an imaginary ball with forehand or backhand swings. The final backhand groundstroke for each player at the backcourt baseline was analyzed. Pelvic rotation and lower extremity motion were quantified using 3D video analysis from frontal and sagittal plane camera views reconstructed to 3D using DLT methods. Plantar flexion of ankle and supination of the front foot were displayed for both Net and Level groups during the late phase of the front foot step. The timings of the peak pelvis rotational velocity and peak pelvis rotational acceleration showed different pattern for Net and Level groups. The peak timing of the pelvis rotational velocity of the Level group occurred during the late phase of the step, suggesting an increase in the risk of inversion ankle sprain and a decrease in stroke power compared to the Net group

Influence of increasing knee flexion angle on knee-ankle varus stress during single-leg jump landing

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Mariam A. Ameer, PhD

2017-12-01

Full Text Available Objectives: The primary aim of this study was to identify the relationship between the peak knee flexion angle and knee-ankle varus stress in the landing phase of the single-leg jump during running. Methods: Fifteen male handball players from the first Saudi Arabian handball team were incorporated in this study. Each player performed a single-leg jump-land after running a fixed distance of 450 cm. The data were measured using a 3D motion analysis system. The maximum knee flexion angle, knee varus angle, centre of pressure pathway in the medio-lateral direction, and ankle varus moment were measured. Results: The Pearson Product Moment Correlation showed that a greater knee flexion angle was related to a greater lateral displacement of the centre of pressure (r = 0.794, P = 0.000, a greater ankle varus moment (r = 0.707, P = 0.003, and a greater knee varus angle (r = 0.753, P = 0.001. In addition, the greater ankle varus moment was related to the greater lateral displacement of the centre of pressure (r = 0.734, P = 0.002. Conclusions: These findings may help physical therapists and conditioning professionals to understand the impact of increasing knee flexion angle on the lower limb joints. Such findings may help to develop training protocols for enhancing the lateral body reaction during the landing phase of the single-leg jump, which may protect the knee and ankle joints from excessive varus stresses. Keywords: 3D motion analysis, Ankle kinetic, Centre of pressure pathway, Handball playing, Knee kinematic, Single-leg jump

Detection method of flexion relaxation phenomenon based on wavelets for patients with low back pain

Science.gov (United States)

Nougarou, François; Massicotte, Daniel; Descarreaux, Martin

2012-12-01

The flexion relaxation phenomenon (FRP) can be defined as a reduction or silence of myoelectric activity of the lumbar erector spinae muscle during full trunk flexion. It is typically absent in patients with chronic low back pain (LBP). Before any broad clinical utilization of this neuromuscular response can be made, effective, standardized, and accurate methods of identifying FRP limits are needed. However, this phenomenon is clearly more difficult to detect for LBP patients than for healthy patients. The main goal of this study is to develop an automated method based on wavelet transformation that would improve time point limits detection of surface electromyography signals of the FRP in case of LBP patients. Conventional visual identification and proposed automated methods of time point limits detection of relaxation phase were compared on experimental data using criteria of accuracy and repeatability based on physiological properties. The evaluation demonstrates that the use of wavelet transform (WT) yields better results than methods without wavelet decomposition. Furthermore, methods based on wavelet per packet transform are more effective than algorithms employing discrete WT. Compared to visual detection, in addition to demonstrating an obvious saving of time, the use of wavelet per packet transform improves the accuracy and repeatability in the detection of the FRP limits. These results clearly highlight the value of the proposed technique in identifying onset and offset of the flexion relaxation response in LBP subjects.

Motor unit activation patterns during concentric wrist flexion in humans with different muscle fibre composition.

Science.gov (United States)

Søgaard, K; Christensen, H; Fallentin, N; Mizuno, M; Quistorff, B; Sjøgaard, G

1998-10-01

Muscle activity was recorded from the flexor carpi radialis muscle during static and dynamic-concentric wrist flexion in six subjects, who had exhibited large differences in histochemically identified muscle fibre composition. Motor unit recruitment patterns were identified by sampling 310 motor units and counting firing rates in pulses per second (pps). During concentric wrist flexion at 30% of maximal exercise intensity the mean firing rate was 27 (SD 13) pps. This was around twice the value of 12 (SD 5) pps recorded during sustained static contraction at 30% of maximal voluntary contraction, despite a larger absolute force level during the static contraction. A similar pattern of higher firing rates during dynamic exercise was seen when concentric wrist flexion at 60% of maximal exercise intensity [30 (SD 14) pps] was compared with sustained static contraction at 60% of maximal voluntary contraction [19 (SD 8) pps]. The increase in dynamic exercise intensity was accomplished by recruitment of additional motor units rather than by increasing the firing rate as during static contractions. No difference in mean firing rates was found among subjects with different muscle fibre composition, who had previously exhibited marked differences in metabolic response during corresponding dynamic contractions. It was concluded that during submaximal dynamic contractions motor unit firing rate cannot be deduced from observations during static contractions and that muscle fibre composition may play a minor role.

Outcome of hamstring ligament harvest for Anterior Cruciate Ligament reconstruction with allograft versus autograft: a clinical trial

Directory of Open Access Journals (Sweden)

Mehdi Moghtadaei

2013-11-01

Full Text Available Background: The goal of this study was to evaluate, functional capacity of the knee in flexion and internal rotation after hamstring ligament harvest for Anterior Cruciate Ligament (ACL reconstruction.Methods: Fifty patients (male and 18-45 years old with isolated ACL injury, randomly allocated in two equal groups (in one group, ACL reconstruction was performed with Tibialis Posterior allograft and in another group with quadruple hamstring ligament auto graft and before and 6 months after surgery in both groups isokinetic flexion strength and isometric internal rotation strength of knee evaluated with Biodex System 4 dynamometer and rotational torque recorder, in order. Isokinetic flexion strength evaluated in sitting and prone position; the later position was performed for deep flexion strength evaluation. Also subjective and objective assessment of all patients pre operatively and 6 months post operatively was documented with International Knee Documentation Committee (IKDC questionnaire. In this study for first time, rotational torque strength of knee was recorded with new design measure, from isometric aspect and not isokinetic.Results: Although significant improvements in IKDC scores, flexion and internal rotation capacity of the knee were observed in both groups, post operatively in respect to pre operatively; there was no significant difference between 2 groups. (P<0.05 or more than 95% confidence Interval of the differenceConclusion: This study demonstrates that ACL reconstruction surgery, improves knee performance in flexion and internal rotation, regardless of hamstring tendon harvesting. Considering potential complications of allograft (for example: transfer of harmful diseases from donor to recipient, it is logical to use hamstring auto graft ligament for ACL reconstruction surgery. Because result of this study is not longstanding follow up and limited to male sex, for more worthfull conclusion, we suggest future study in both sex

Limb flexion-induced axial compression and bending in human femoropopliteal artery segments.

Science.gov (United States)

Poulson, William; Kamenskiy, Alexey; Seas, Andreas; Deegan, Paul; Lomneth, Carol; MacTaggart, Jason

2018-02-01

High failure rates of femoropopliteal artery (FPA) interventions are often attributed in part to severe mechanical deformations that occur with limb movement. Axial compression and bending of the FPA likely play significant roles in FPA disease development and reconstruction failure, but these deformations are poorly characterized. The goal of this study was to quantify axial compression and bending of human FPAs that are placed in positions commonly assumed during the normal course of daily activities. Retrievable nitinol markers were deployed using a custom-made catheter system into 28 in situ FPAs of 14 human cadavers. Contrast-enhanced, thin-section computed tomography images were acquired with each limb in the standing (180 degrees), walking (110 degrees), sitting (90 degrees), and gardening (60 degrees) postures. Image segmentation and analysis allowed relative comparison of spatial locations of each intra-arterial marker to determine axial compression and bending using the arterial centerlines. Axial compression in the popliteal artery (PA) was greater than in the proximal superficial femoral artery (SFA) or the adductor hiatus (AH) segments in all postures (P = .02). Average compression in the SFA, AH, and PA ranged from 9% to 15%, 11% to 19%, and 13% to 25%, respectively. The FPA experienced significantly more acute bending in the AH and PA segments compared with the proximal SFA (P < .05) in all postures. In the walking, sitting, and gardening postures, average sphere radii in the SFA, AH, and PA ranged from 21 to 27 mm, 10 to 18 mm, and 8 to 19 mm, whereas bending angles ranged from 150 to 157 degrees, 136 to 147 degrees, and 137 to 148 degrees, respectively. The FPA experiences significant axial compression and bending during limb flexion that occur at even modest limb angles. Moreover, different segments of the FPA appear to undergo significantly different degrees of deformation. Understanding the effects of limb flexion on axial compression and

Effect of prolotherapy on hemiplegic shoulder pain due to rotator cuff tendinopathy: a pilot study

Directory of Open Access Journals (Sweden)

Serdar Kesikburun

2017-03-01

Full Text Available Purpose: The aim of this study was to investigate the effect of prolotherapy on pain and shoulder range of motion in stroke patients with hemiplegic shoulder pain due to rotator cuff tendinopathy. Material and Methods: The data of 10 patients (mean age, 64.2+/-11.6 years who had a history stroke of more than six months and underwent prolotherapy treatment were collected retrospectively. The treatment included 3 sessions of dextrose pr olotherapy injections applied to rotator cuff tendon. Visual analogue scale pain scores and shoulder range of motions measured at baseline and two weeks later after end of the treatment were assessed. Results: Visual analogue scale shoulder pain scores of the patients decreased from 8.2+/-1.1 at baseline to 4.8+/-1.9 after prolotherapy The degrees of shoulder flexion and abduction increased significantly after the treatment. Conclusion: Preliminary results in this pilot study suggested the beneficial effect of proloterapi in the treatmentof hemiplegicshoulderpain. [Cukurova Med J 2017; 42(1.000: 13-18

Relation Between Subacromial Bursitis on Ultrasonography and Efficacy of Subacromial Corticosteroid Injection in Rotator Cuff Disease: A Prospective Comparison Study.

Science.gov (United States)

Lee, Doo-Hyung; Hong, Ji Yeon; Lee, Michael Young; Kwack, Kyu-Sung; Yoon, Seung-Hyun

2017-05-01

To evaluate the correlations between subacromial bursitis (bursal thickening and effusion) on ultrasonography and its response to subacromial corticosteroid injection in patients with rotator cuff disease. Prospective, longitudinal comparison study. University-affiliated tertiary care hospital. Patients with rotator cuff disease (N=69) were classified into 3 groups based on ultrasonographic findings; (1) normative bursa group (group 1, n=23): bursa and effusion thickness 2mm and effusion thickness 2mm. A single subacromial injection with 20mg of triamcinolone acetonide. Visual analog scale (VAS) of shoulder pain, Shoulder Disability Questionnaire (SDQ), angles of active shoulder range of motion (flexion, abduction, external rotation, and internal rotation), and bursa and effusion thickness at pre- and posttreatment at week 8. There were no significant differences between the 3 groups in demographic characteristics pretreatment. Groups 2 and 3 showed a significant difference compared with group 1 in changes on the VAS and abduction; group 3 showed a significant difference compared with group 1 in changes of the SDQ, internal rotation, and external rotation; and all groups showed significant differences when compared with each other (groups 1 and 3, 2 and 3, and 1 and 2) in changes of thickness. A patient with ultrasonographic observation of subacromial bursitis, instead of normative bursa, can expect better outcome with subacromial corticosteroid injection. Therefore, we recommend a careful selection of patients using ultrasonography prior to injection. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Magnetic resonance imaging of the posterior cruciate ligament in flexion.

Science.gov (United States)

Craddock, William; Smithers, Troy; Harris, Craig; du Moulin, William; Molnar, Robert

2018-06-01

Posterior cruciate ligament (PCL) injuries of the knee are common and sometimes difficult to diagnose. Magnetic resonance imaging (MRI), performed using standard orthogonal plane views, is the investigation of choice. It can be particularly difficult to differentiate acute partial and complete tears and identify elongation of chronic healed tears. The aim of the paper is to describe a new method of positioning the patient with the knee flexed at 90°, allowing the PCL to be visualised in a position of greatest length and tension which may assist in differentiating and identifying these injuries. Four symptomatic patients with suspected PCL injuries, two acute and two chronic, were MRI scanned using a routine protocol with the knee in extension before performing oblique sagittal fast spin-echo (FSE) proton-density (PD) sequences with the knee positioned in 90° of flexion. The appearance of the PCLs were then qualitatively assessed. MRI scanning with the knee in flexion identified more extensive PCL injury than standard imaging. In the two patients with acute injuries, partial tears on the standard orthogonal plane views were found to be complete ruptures. In the two patients with chronic injuries, elongation of the PCL not identifiable on the standard orthogonal plane views was apparent. MRI scanning of the PCL with the knee flexed at 90° may help in differentiating partial and complete ruptures of the PCL and identifying elongation of the PCL in chronic injuries. Copyright © 2018 Elsevier B.V. All rights reserved.

La réflexion stratégique, objet et outil de recherche pour le management stratégique ?

OpenAIRE

Torset, Christophe

2005-01-01

International audience; La littérature sur la formation de la stratégie utilise fréquemment l'expression « réflexion stratégique ». Cette notion est susceptible de faciliter l'analyse des processus en favorisant une démarche plus systémique, capable de regrouper et prendre en considération différents niveaux organisationnels et différentes formes de genèse des idées stratégiques. Cette communication propose une revue des caractéristiques de la notion de réflexion stratégique, au regard notamm...

On the experimental prediction of the stability threshold speed caused by rotating damping

Science.gov (United States)

Vervisch, B.; Derammelaere, S.; Stockman, K.; De Baets, P.; Loccufier, M.

2016-08-01

An ever increasing demand for lighter rotating machinery and higher operating speeds results in a raised probability of instabilities. Rotating damping is one of the reasons, instability occurs. Rotating damping, or rotor internal damping, is the damping related to all rotating parts while non-rotating damping appearing in the non-rotating parts. The present study describes a rotating setup, designed to investigate rotating damping experimentally. An efficient experimental procedure is presented to predict the stability threshold of a rotating machine. The setup consists of a long thin shaft with a disk in the middle and clamped boundary conditions. The goal is to extract the system poles as a function of the rotating speed. The real parts of these poles are used to construct the decay rate plot, which is an indication for the stability. The efficiency of the experimental procedure relies on the model chosen for the rotating shaft. It is shown that the shaft behavior can be approximated by a single degree of freedom model that incorporates a speed dependent damping. As such low measurement effort and only one randomly chosen measurement location are needed to construct the decay rate plot. As an excitation, an automated impact hammer is used and the response is measured by eddy current probes. The proposed method yields a reliable prediction of the stability threshold speed which is validated through measurements.

Control system for several rotating mirror camera synchronization operation

Science.gov (United States)

Liu, Ningwen; Wu, Yunfeng; Tan, Xianxiang; Lai, Guoji

1997-05-01

This paper introduces a single chip microcomputer control system for synchronization operation of several rotating mirror high-speed cameras. The system consists of four parts: the microcomputer control unit (including the synchronization part and precise measurement part and the time delay part), the shutter control unit, the motor driving unit and the high voltage pulse generator unit. The control system has been used to control the synchronization working process of the GSI cameras (driven by a motor) and FJZ-250 rotating mirror cameras (driven by a gas driven turbine). We have obtained the films of the same objective from different directions in different speed or in same speed.

Knee flexion with quadriceps cocontraction: A new therapeutic exercise for the early stage of ACL rehabilitation.

Science.gov (United States)

Biscarini, Andrea; Contemori, Samuele; Busti, Daniele; Botti, Fabio M; Pettorossi, Vito E

2016-12-08

Quadriceps strengthening exercises designed for the early phase of anterior cruciate ligament (ACL) rehabilitation should limit the anterior tibial translation developed by quadriceps contraction near full knee extension, in order to avoid excessive strain on the healing tissue. We hypothesize that knee-flexion exercises with simultaneous voluntary contraction of quadriceps (voluntary quadriceps cocontraction) can yield considerable levels of quadriceps activation while preventing the tibia from translating forward relative to the femur. Electromyographic activity in quadriceps and hamstring muscles was measured in 20 healthy males during isometric knee-flexion exercises executed near full knee extension with maximal voluntary effort of quadriceps cocontraction and external resistance (R) ranging from 0% to 60% of the 1-repetition maximum (1RM). Biomechanical modeling was applied to derive the shear (anterior/posterior) tibiofemoral force developed in each exercise condition. Isometric knee-flexion exercises with small external resistance (R=10% 1RM) and maximal voluntary effort of quadriceps cocontraction yielded a net posterior (ACL-unloading) tibial pull (P=0.005) and levels of activation of 32%, 50%, and 45% of maximum voluntary isometric contraction, for the rectus femoris, vastus medialis, and vastus lateralis, respectively. This exercise might potentially rank as one of the most appropriate quadriceps strengthening interventions in the early phase of ACL rehabilitation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Do the cerebellar tonsils move during flexion and extension of the neck in patients with Chiari I malformation? A radiological study with clinical implications.

Science.gov (United States)

Tubbs, R Shane; Kirkpatrick, Christina M; Rizk, Elias; Chern, Joshua J; Oskouian, Rod J; Oakes, W Jerry

2016-03-01

In the past, diagnosis of the Chiari I malformation has primarily been made on midsagittal MRI. We hypothesized that based on the frequent presentation of opisthotonos in patients with hindbrain hernia (primarily Chiari II malformation but sometimes Chiari I malformation) that the hyperextension might be a compensatory technique used by such patients to bring the cerebellar tonsils up out of the cervical spine. This prospective study reviewed imaging of patients with Chiari I malformation who underwent flexion/extension MRI for evaluation of their hindbrain herniation. Age-matched controls were used for comparison. In general, there was elevation of the cerebellar tonsils with extension and increased descent with flexion of the cervical spine. In 72 % of patients, flexion of the neck resulted in descent of the cerebellar tonsils. In 64 % of patients, extension of the neck resulted in ascent of the cerebellar tonsils. In the 14 patients with an associated syrinx, 71 % were found to have caudal movement of the cerebellar tonsils with neck flexion, and only 43 % were observed to have any movement of the cerebellar tonsils in neck extension compared to patients without a syrinx where ascent of the tonsils was seen in only nine during neck extension. Two patients were observed to have the reverse finding of ascent of the cerebellar tonsils with neck flexion and descent of the cerebellar tonsils with neck extension. Five patients had no movement of the cerebellar tonsils in either flexion or extension of the neck, and one of these had a small syrinx. Although minimal and not in all patients, we observed elevation of the herniated cerebellar tonsils with extension of the cervical spine in patients with Chiari I malformation. This finding provides evidence as to why some patients with hindbrain herniation present with opisthotonos and supports earlier findings that CSF flow is reduced at the craniocervical junction in flexion in patients with Chiari I malformation.

Variability of ischiofemoral space dimensions with changes in hip flexion: an MRI study

International Nuclear Information System (INIS)

Johnson, Adam C.; Howe, Benjamin M.; Hollman, John H.; Finnoff, Jonathan T.

2017-01-01

The primary aim of this study was to determine if ischiofemoral space (IFS) dimensions vary with changes in hip flexion as a result of placing a bolster behind the knees during magnetic resonance imaging (MRI). A secondary aim was to determine if IFS dimensions vary between supine and prone hip neutral positions. The study employed a prospective design. Sports medicine center within a tertiary care institution. Five male and five female adult subjects (age mean = 29.2, range = 23-35; body mass index [BMI] mean = 23.5, range = 19.5-26.6) were recruited to participate in the study. An axial, T1-weighted MRI sequence of the pelvis was obtained of each subject in a supine position with their hips in neutral and flexed positions, and in a prone position with their hips in neutral position. Supine hip flexion was induced by placing a standard, 9-cm-diameter MRI knee bolster under the subject's knees. The order of image acquisition (supine hip neutral, supine hip flexed, prone hip neutral) was randomized. The IFS dimensions were then measured on a separate workstation. The investigator performing the IFS measurements was blinded to the subject position for each image. The main outcome measurements were the IFS dimensions acquired with MRI. The mean IFS dimensions in the prone position were 28.25 mm (SD 5.91 mm, standard error mean 1.32 mm). In the supine hip neutral position, the IFS dimensions were 25.1 (SD 5.6) mm. The mean difference between the two positions of 3.15 (3.6) mm was statistically significant (95 % CI of the difference = 1.4 to 4.8 mm, t_1_9 = 3.911, p =.001). The mean IFS dimensions in the hip flexed position were 36.9 (SD 5.7) mm. The mean difference between the two supine positions of 11.8 (4.1) mm was statistically significant (95 % CI of the difference = 9.9 to 13.7 mm, t_1_9 = 12.716, p <.001). Our findings demonstrate that the IFS measurements obtained with MRI are dependent upon patient positioning with respect to hip flexion and supine versus

Variability of ischiofemoral space dimensions with changes in hip flexion: an MRI study

Energy Technology Data Exchange (ETDEWEB)

Johnson, Adam C.; Howe, Benjamin M. [Mayo Clinic College of Medicine, Department of Radiology, Rochester, MN (United States); Hollman, John H.; Finnoff, Jonathan T. [Mayo Clinic College of Medicine, Department of Physical Medicine and Rehabilitation, Rochester, MN (United States)

2017-01-15

The primary aim of this study was to determine if ischiofemoral space (IFS) dimensions vary with changes in hip flexion as a result of placing a bolster behind the knees during magnetic resonance imaging (MRI). A secondary aim was to determine if IFS dimensions vary between supine and prone hip neutral positions. The study employed a prospective design. Sports medicine center within a tertiary care institution. Five male and five female adult subjects (age mean = 29.2, range = 23-35; body mass index [BMI] mean = 23.5, range = 19.5-26.6) were recruited to participate in the study. An axial, T1-weighted MRI sequence of the pelvis was obtained of each subject in a supine position with their hips in neutral and flexed positions, and in a prone position with their hips in neutral position. Supine hip flexion was induced by placing a standard, 9-cm-diameter MRI knee bolster under the subject's knees. The order of image acquisition (supine hip neutral, supine hip flexed, prone hip neutral) was randomized. The IFS dimensions were then measured on a separate workstation. The investigator performing the IFS measurements was blinded to the subject position for each image. The main outcome measurements were the IFS dimensions acquired with MRI. The mean IFS dimensions in the prone position were 28.25 mm (SD 5.91 mm, standard error mean 1.32 mm). In the supine hip neutral position, the IFS dimensions were 25.1 (SD 5.6) mm. The mean difference between the two positions of 3.15 (3.6) mm was statistically significant (95 % CI of the difference = 1.4 to 4.8 mm, t{sub 19} = 3.911, p =.001). The mean IFS dimensions in the hip flexed position were 36.9 (SD 5.7) mm. The mean difference between the two supine positions of 11.8 (4.1) mm was statistically significant (95 % CI of the difference = 9.9 to 13.7 mm, t{sub 19} = 12.716, p <.001). Our findings demonstrate that the IFS measurements obtained with MRI are dependent upon patient positioning with respect to hip flexion and

Rotational inhomogeneities from pre-big bang?

International Nuclear Information System (INIS)

Giovannini, Massimo

2005-01-01

The evolution of the rotational inhomogeneities is investigated in the specific framework of four-dimensional pre-big bang models. While minimal (dilaton-driven) scenarios do not lead to rotational fluctuations, in the case of non-minimal (string-driven) models, fluid sources are present in the pre-big bang phase. The rotational modes of the geometry, coupled to the divergenceless part of the velocity field, can then be amplified depending upon the value of the barotropic index of the perfect fluids. In the light of a possible production of rotational inhomogeneities, solutions describing the coupled evolution of the dilaton field and of the fluid sources are scrutinized in both the string and Einstein frames. In semi-realistic scenarios, where the curvature divergences are regularized by means of a non-local dilaton potential, the rotational inhomogeneities are amplified during the pre-big bang phase but they decay later on. Similar analyses can also be performed when a contraction occurs directly in the string frame metric

Rotational inhomogeneities from pre-big bang?

Energy Technology Data Exchange (ETDEWEB)

Giovannini, Massimo [Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland)

2005-01-21

The evolution of the rotational inhomogeneities is investigated in the specific framework of four-dimensional pre-big bang models. While minimal (dilaton-driven) scenarios do not lead to rotational fluctuations, in the case of non-minimal (string-driven) models, fluid sources are present in the pre-big bang phase. The rotational modes of the geometry, coupled to the divergenceless part of the velocity field, can then be amplified depending upon the value of the barotropic index of the perfect fluids. In the light of a possible production of rotational inhomogeneities, solutions describing the coupled evolution of the dilaton field and of the fluid sources are scrutinized in both the string and Einstein frames. In semi-realistic scenarios, where the curvature divergences are regularized by means of a non-local dilaton potential, the rotational inhomogeneities are amplified during the pre-big bang phase but they decay later on. Similar analyses can also be performed when a contraction occurs directly in the string frame metric.

Bridging Graft in Irreparable Massive Rotator Cuff Tears: Autogenic Biceps Graft versus Allogenic Dermal Patch Graft.

Science.gov (United States)

Rhee, Sung Min; Oh, Joo Han

2017-12-01

Few comparative studies have reported on the use of biologic grafts for irreparable massive rotator cuff tears. The purpose of this study was to assess the results of arthroscopic bridging graft in irreparable massive rotator cuff tears using an autogenic long head of biceps tendon (LHBT) or an allogenic dermal patch (ADP). We retrospectively reviewed 24 patients treated using the LHBT (group I) and eight patients with complete rupture of the LHBT treated using an ADP (group II) since 2011. Preoperative Goutallier's fatty degeneration, range of motion (ROM), visual analogue scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, and Quick Disabilities of the Arm, Shoulder, and Hand (DASH) score were assessed and healing failure was evaluated at 1 year after surgery by ultrasonography or magnetic resonance imaging. The mean fatty degeneration in groups I and II was 3.9 and 3.6 for the supraspinatus ( p = 0.288), 2.7 and 2.9 for the infraspinatus ( p = 0.685), 0.9 and 1.3 for the subscapularis ( p = 0.314), and 1.3 and 3.0 for the teres minor ( p = 0.005), respectively. Subscapularis tears were found in 8 patients (33.3%) in group I and in 7 patients (87.5%) in group II ( p = 0.023). Mean ROMs and functional scores improved significantly in group I (forward flexion: 121.7° to 153.3°, p = 0.010; external rotation: 32.7° to 52.7°, p = 0.001; external rotation at 90°: 63.3° to 74.5°, p = 0.031; internal rotation: T10.5 to T9.3, p = 0.045; VAS: 7.0 to 1.1, p rotator cuff tears, especially in patients with severe fatty degeneration in the teres minor or combined biceps and subscapularis tears.

An extended OpenSim knee model for analysis of strains of connective tissues.

Science.gov (United States)

Marieswaran, M; Sikidar, Arnab; Goel, Anu; Joshi, Deepak; Kalyanasundaram, Dinesh

2018-04-17

OpenSim musculoskeletal models provide an accurate simulation environment that eases limitations of in vivo and in vitro studies. In this work, a biomechanical knee model was formulated with femoral articular cartilages and menisci along with 25 connective tissue bundles representing ligaments and capsules. The strain patterns of the connective tissues in the presence of femoral articular cartilage and menisci in the OpenSim knee model was probed in a first of its kind study. The effect of knee flexion (0°-120°), knee rotation (- 40° to 30°) and knee adduction (- 15° to 15°) on the anterior cruciate, posterior cruciate, medial collateral, lateral collateral ligaments and other connective tissues were studied by passive simulation. Further, a new parameter for assessment of strain namely, the differential inter-bundle strain of the connective tissues were analyzed to provide new insights for injury kinematics. ACL, PCL, LCL and PL was observed to follow a parabolic strain pattern during flexion while MCL represented linear strain patterns. All connective tissues showed non-symmetric parabolic strain variation during rotation. During adduction, the strain variation was linear for the knee bundles except for FL, PFL and TL. Strains higher than 0.1 were observed in most of the bundles during lateral rotation followed by abduction, medial rotation and adduction. In the case of flexion, highest strains were observed in aACL and aPCL. A combination of strains at a flexion of 0° with medial rotation of 30° or a flexion of 80° with rotation of 30° are evaluated as rupture-prone kinematics.

49 CFR 572.145 - Upper and lower torso assemblies and torso flexion test procedure.

Science.gov (United States)

2010-10-01

...) ANTHROPOMORPHIC TEST DEVICES 3-year-Old Child Crash Test Dummy, Alpha Version § 572.145 Upper and lower torso... lumbar spine and abdomen of a fully assembled dummy (drawing 210-0000) to flexion articulation between... in paragraph (c) of this section, the lumbar spine-abdomen assembly shall flex by an amount that...

Ultrasound assessment of fascial connectivity in the lower limb during maximal cervical flexion: technical aspects and practical application of automatic tracking.

Science.gov (United States)

Cruz-Montecinos, Carlos; Cerda, Mauricio; Sanzana-Cuche, Rodolfo; Martín-Martín, Jaime; Cuesta-Vargas, Antonio

2016-01-01

The fascia provides and transmits forces for connective tissues, thereby regulating human posture and movement. One way to assess the myofascial interaction is a fascia ultrasound recording. Ultrasound can follow fascial displacement either manually or automatically through two-dimensional (2D) method. One possible method is the iterated Lucas-Kanade Pyramid (LKP) algorithm, which is based on automatic pixel tracking during passive movements in 2D fascial displacement assessments. Until now, the accumulated error over time has not been considered, even though it could be crucial for detecting fascial displacement in low amplitude movements. The aim of this study was to assess displacement of the medial gastrocnemius fascia during cervical spine flexion in a kyphotic posture with the knees extended and ankles at 90°. The ultrasound transducer was placed on the extreme dominant belly of the medial gastrocnemius. Displacement was calculated from nine automatically selected tracking points. To determine cervical flexion, an established 2D marker protocol was implemented. Offline pressure sensors were used to synchronize the 2D kinematic data from cervical flexion and deep fascia displacement of the medial gastrocnemius. Fifteen participants performed the cervical flexion task. The basal tracking error was 0.0211 mm. In 66 % of the subjects, a proximal fascial tissue displacement of the fascia above the basal error (0.076 mm ± 0.006 mm) was measured. Fascia displacement onset during cervical spine flexion was detected over 70 % of the cycle; however, only when detected for more than 80 % of the cycle was displacement considered statistically significant as compared to the first 10 % of the cycle (ANOVA, p < 0.05). By using an automated tracking method, the present analyses suggest statistically significant displacement of deep fascia. Further studies are needed to corroborate and fully understand the mechanisms associated with these results.

Mental rotation of anthropoid hands: a chronometric study

Directory of Open Access Journals (Sweden)

L.G. Gawryszewski

2007-03-01

Full Text Available It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human. Twenty-four right-handed volunteers (13 males and 11 females were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0º (fingers upwards to 90º lateral (fingers pointing away from the midline, 180º (fingers downwards and 90º medial (finger towards the midline. The results showed an effect of rotation angle (F(3, 69 = 19.57, P < 0.001, but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05. This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.

An Accurate Full-flexion Anterolateral Portal for Needle Placement in the Knee Joint With Dry Osteoarthritis.

Science.gov (United States)

Hussein, Mohamed

2017-07-01

Accurate delivery of an injection into the intra-articular space of the knee is achieved in only two thirds of knees when using the standard anterolateral portal. The use of a modified full-flexion anterolateral portal provides a highly accurate, less painful, and more effective method for reproducible intra-articular injection without the need for ultrasonographic or fluoroscopic guidance in patients with dry osteoarthritis of the knee. The accuracy of needle placement was assessed in a prospective series of 140 consecutive injections in patients with symptomatic degenerative knee arthritis without clinical knee effusion. Procedural pain was determined using the Numerical Rating Scale. The accuracy rates of needle placement were confirmed with fluoroscopic imaging to document the dispersion pattern of injected contrast material. Using the standard anterolateral portal, 52 of 70 injections were confirmed to have been placed in the intra-articular space on the first attempt (accuracy rate, 74.2%). Using the modified full-flexion anterolateral portal, 68 of 70 injections were placed in the intra-articular space on the first attempt (accuracy rate, 97.1%; P = 0.000). This study revealed that using the modified full-flexion anterolateral portal for injections into the knee joint resulted in more accurate and less painful injections than those performed by the same orthopaedic surgeon using the standard anterolateral portal. In addition, the technique offered therapeutic delivery into the joint without the need for fluoroscopic confirmation. Therapeutic Level II.

A comparison of functional outcomes in patients undergoing revision arthroscopic repair of massive rotator cuff tears with and without arthroscopic suprascapular nerve release

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Savoie III FH

2016-10-01

greater improvement in active forward flexion, strength, and pain relief. Conclusion: Patients who underwent concomitant release of the suprascapular nerve during revision RTCR had greater overall improvement as noted in pain relief, active forward flexion, and strength, than a comparable group without nerve release. Keywords: muscle atrophy, suprascapular nerve release, revision rotator cuff repair, atrophy 

Semiclassical approach to giant resonances of rotating nuclei

International Nuclear Information System (INIS)

Winter, J.

1983-01-01

Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large-amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. (author)

Influence of defects on the vibrations of rotating systems

International Nuclear Information System (INIS)

Lazarus, A.

2008-01-01

For high rotation speeds, the imperfections (cracks, anisotropy...) of rotating machinery of the energy sector lead to a specific vibratory behavior which can damage the machine. The simulation of rotating machinery are usually realized for systems without defect. The aim of this thesis is to understand the influence of defects and to propose an algorithm to predict the dynamical behavior. In a first part the author studies the simplified rotating oscillators to propose a numerical method in order to taking into account the dynamic of these systems. This method is then applied to real rotating machinery with the Cast3m software. The numerical results are validated with experiments. (A.L.B.)

A successful backward step correlates with hip flexion moment of supporting limb in elderly people.

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Takeuchi, Yahiko

2018-01-01

The objective of this study was to determine the positional relationship between the center of mass (COM) and the center of pressure (COP) at the time of step landing, and to examine their relationship with the joint moments exerted by the supporting limb, with regard to factors of the successful backward step response. The study population comprised 8 community-dwelling elderly people that were observed to take successive multi steps after the landing of a backward stepping. Using a motion capture system and force plate, we measured the COM, COP and COM-COP deviation distance on landing during backward stepping. In addition, we measured the moment of the supporting limb joint during backward stepping. The multi-step data were compared with data from instances when only one step was taken (single-step). Variables that differed significantly between the single- and multi-step data were used as objective variables and the joint moments of the supporting limb were used as explanatory variables in single regression analyses. The COM-COP deviation in the anteroposterior was significantly larger in the single-step. A regression analysis with COM-COP deviation as the objective variable obtained a significant regression equation in the hip flexion moment (R2 = 0.74). The hip flexion moment of supporting limb was shown to be a significant explanatory variable in both the PS and SS phases for the relationship with COM-COP distance. This study found that to create an appropriate backward step response after an external disturbance (i.e. the ability to stop after 1 step), posterior braking of the COM by a hip flexion moment are important during the single-limbed standing phase.

Increasing trunk flexion transforms human leg function into that of birds despite different leg morphology.

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Aminiaghdam, Soran; Rode, Christian; Müller, Roy; Blickhan, Reinhard

2017-02-01

Pronograde trunk orientation in small birds causes prominent intra-limb asymmetries in the leg function. As yet, it is not clear whether these asymmetries induced by the trunk reflect general constraints on the leg function regardless of the specific leg architecture or size of the species. To address this, we instructed 12 human volunteers to walk at a self-selected velocity with four postures: regular erect, or with 30 deg, 50 deg and maximal trunk flexion. In addition, we simulated the axial leg force (along the line connecting hip and centre of pressure) using two simple models: spring and damper in series, and parallel spring and damper. As trunk flexion increases, lower limb joints become more flexed during stance. Similar to birds, the associated posterior shift of the hip relative to the centre of mass leads to a shorter leg at toe-off than at touchdown, and to a flatter angle of attack and a steeper leg angle at toe-off. Furthermore, walking with maximal trunk flexion induces right-skewed vertical and horizontal ground reaction force profiles comparable to those in birds. Interestingly, the spring and damper in series model provides a superior prediction of the axial leg force across trunk-flexed gaits compared with the parallel spring and damper model; in regular erect gait, the damper does not substantially improve the reproduction of the human axial leg force. In conclusion, mimicking the pronograde locomotion of birds by bending the trunk forward in humans causes a leg function similar to that of birds despite the different morphology of the segmented legs. © 2017. Published by The Company of Biologists Ltd.

Complex structure of Kerr geometry and rotating 'photon rocket' solutions

International Nuclear Information System (INIS)

Burinskii, Alexander

2003-01-01

In the frame of the Kerr-Schild approach, we obtain a generalization of the Kerr solution to a nonstationary case corresponding to a rotating source moving with arbitrary acceleration. Similar to the Kerr solution, the solutions obtained have geodesic and shearfree principal null congruence. The current parameters of the solutions are determined by a complex retarded-time construction via a given complex worldline of source. The real part of the complex worldline defines the values of the boost and acceleration while the imaginary part controls the rotation. The acceleration of the source is accompanied by lightlike radiation along the principal null congruence. The solutions obtained generalize to the rotating case the known Kinnersley class of the 'photon rocket' solutions

Study of a Microfluidic Chip Integrating Single Cell Trap and 3D Stable Rotation Manipulation

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Liang Huang

2016-08-01

Full Text Available Single cell manipulation technology has been widely applied in biological fields, such as cell injection/enucleation, cell physiological measurement, and cell imaging. Recently, a biochip platform with a novel configuration of electrodes for cell 3D rotation has been successfully developed by generating rotating electric fields. However, the rotation platform still has two major shortcomings that need to be improved. The primary problem is that there is no on-chip module to facilitate the placement of a single cell into the rotation chamber, which causes very low efficiency in experiment to manually pipette single 10-micron-scale cells into rotation position. Secondly, the cell in the chamber may suffer from unstable rotation, which includes gravity-induced sinking down to the chamber bottom or electric-force-induced on-plane movement. To solve the two problems, in this paper we propose a new microfluidic chip with manipulation capabilities of single cell trap and single cell 3D stable rotation, both on one chip. The new microfluidic chip consists of two parts. The top capture part is based on the least flow resistance principle and is used to capture a single cell and to transport it to the rotation chamber. The bottom rotation part is based on dielectrophoresis (DEP and is used to 3D rotate the single cell in the rotation chamber with enhanced stability. The two parts are aligned and bonded together to form closed channels for microfluidic handling. Using COMSOL simulation and preliminary experiments, we have verified, in principle, the concept of on-chip single cell traps and 3D stable rotation, and identified key parameters for chip structures, microfluidic handling, and electrode configurations. The work has laid a solid foundation for on-going chip fabrication and experiment validation.

The effects of denervation, reinnervation, and muscle imbalance on functional muscle length and elbow flexion contracture following neonatal brachial plexus injury.

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Weekley, Holly; Nikolaou, Sia; Hu, Liangjun; Eismann, Emily; Wylie, Christopher; Cornwall, Roger

2012-08-01

The pathophysiology of paradoxical elbow flexion contractures following neonatal brachial plexus injury (NBPI) is incompletely understood. The current study tests the hypothesis that this contracture occurs by denervation-induced impairment of elbow flexor muscle growth. Unilateral forelimb paralysis was created in mice in four neonatal (5-day-old) BPI groups (C5-6 excision, C5-6 neurotomy, C5-6 neurotomy/repair, and C5-T1 global excision), one non-neonatal BPI group (28-day-old C5-6 excision), and two neonatal muscle imbalance groups (triceps tenotomy ± C5-6 excision). Four weeks post-operatively, motor function, elbow range of motion, and biceps/brachialis functional lengths were assessed. Musculocutaneous nerve (MCN) denervation and reinnervation were assessed immunohistochemically. Elbow flexion motor recovery and elbow flexion contractures varied inversely among the neonatal BPI groups. Contracture severity correlated with biceps/brachialis shortening and MCN denervation (relative axon loss), with no contractures occurring in mice with MCN reinnervation (presence of growth cones). No contractures or biceps/brachialis shortening occurred following non-neonatal BPI, regardless of denervation or reinnervation. Neonatal triceps tenotomy did not cause contractures or biceps/brachialis shortening, nor did it worsen those following neonatal C5-6 excision. Denervation-induced functional shortening of elbow flexor muscles leads to variable elbow flexion contractures depending on the degree, permanence, and timing of denervation, independent of muscle imbalance. Copyright © 2012 Orthopaedic Research Society.

Influence of knee flexion angle and transverse drill angle on creation of femoral tunnels in double-bundle anterior cruciate ligament reconstruction using the transportal technique: Three-dimensional computed tomography simulation analysis.

Science.gov (United States)

Choi, Chong Hyuk; Kim, Sung-Jae; Chun, Yong-Min; Kim, Sung-Hwan; Lee, Su-Keon; Eom, Nam-Kyu; Jung, Min

2018-01-01

The purpose of this study was to find appropriate flexion angle and transverse drill angle for optimal femoral tunnels of anteromedial (AM) bundle and posterolateral (PL) bundle in double-bundle ACL reconstruction using transportal technique. Thirty three-dimensional knee models were reconstructed. Knee flexion angles were altered from 100° to 130° at intervals of 10°. Maximum transverse drill angle (MTA), MTA minus 10° and 20° were set up. Twelve different tunnels were determined by four flexion angles and three transverse drill angles for each bundle. Tunnel length, wall breakage, inter-tunnel communication and graft-bending angle were assessed. Mean tunnel length of AM bundle was >30mm at 120° and 130° of flexion in all transverse drill angles. Mean tunnel length of PL bundle was >30mm during every condition. There were ≥1 cases of wall breakage except at 120° and 130° of flexion with MTA for AM bundle. There was no case of wall breakage for PL bundle. Considering inter-tunnel gap of >2mm without communication and obtuse graft-bending angle, 120° of flexion and MTA could be recommended as optimal condition for femoral tunnels of AM and PL bundles. Flexion angle and transverse drill angle had combined effect on femoral tunnel in double-bundle ACL reconstruction using transportal technique. Achieving flexion angle of 120° and transverse drill angle close to the medial femoral condyle could be recommended as optimal condition for femoral tunnels of AM and PL bundles to avoid insufficient tunnel length, wall breakage, inter-tunnel communication and acute graft-bending angle. Copyright © 2017 Elsevier B.V. All rights reserved.

Depression and Anxiety in Traumatic Brachial Plexus Injury Patients Are Associated With Reduced Motor Outcome After Surgical Intervention for Restoration of Elbow Flexion.

Science.gov (United States)

Wilson, Thomas J; Chang, Kate W C; Yang, Lynda J-S

2016-06-01

Depression has been associated with poor outcomes in neurosurgical patients, including increased pain, poorer functional recovery, delayed return to work, and decreased patient satisfaction. No reports exist regarding an association of psychiatric diagnoses with outcomes after brachial plexus reconstruction. As outcomes and patient satisfaction become increasingly important to payers and physician reimbursement, assessing modifiable preoperative risk factors for their association with poor outcome and patient satisfaction is imperative. To analyze patients undergoing brachial plexus reconstruction to assess the relationship of depression/anxiety with functional outcome. Data were collected retrospectively on all patients who underwent brachial plexus reconstruction to restore elbow flexion between 2005 and 2013. Elbow flexion, graded via the Medical Research Council scale, was assessed at latest follow-up. Multiple variables, including the presence of Axis I psychiatric diagnoses, were assessed for their association with the dichotomous outcome of Medical Research Council scale score ≥3 (antigravity) vs <3 elbow flexion. Standard statistical methods were used. Thirty-seven patients met inclusion criteria. The median postsurgical follow-up time was 21 months. Operations included neurolysis (n = 3), nerve graft repair (n = 6), and nerve transfer (n = 28). Depression was present in 10 of 37 patients (27%). Of variables tested, only depression was associated with poor elbow flexion outcome (odds ratio: 6.038; P = .04). Preoperative depression is common after brachial plexus injury. The presence of depression is associated with reduced elbow flexion recovery after reconstruction. Our data suggest assessment and treatment of preoperative mental health is important in designing a comprehensive postoperative management plan to optimize outcomes and patient satisfaction. MRC, Medical Research CouncilTBI, traumatic brain injury.

Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes.

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M Eriksson Crommert

Full Text Available The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0° to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA, obliquus internus (OI with intra-muscular electrodes, and from rectus abdominis (RA, erector spinae (ES and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.

Effects of a 16-week Pilates exercises training program for isometric trunk extension and flexion strength.

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Kliziene, Irina; Sipaviciene, Saule; Vilkiene, Jovita; Astrauskiene, Audrone; Cibulskas, Gintautas; Klizas, Sarunas; Cizauskas, Ginas

2017-01-01

To evaluate the effects of Pilates exercises designed to improve isometric trunk extension and flexion strength of muscles in women with chronic low back pain (cLBP). Female volunteers with cLBP were divided into an experimental group (EG; n = 27) and a control group (CG; n = 27). Pilates exercises were performed twice per week by the EG; the duration of each session was 60 min. The program lasted for 16 weeks; thus patients underwent a total of 32 exercise sessions. The maximum isometric waist bending strength of the EG had improved significantly (p = 0.001) after 16 weeks of the Pilates program. The results of trunk flexion muscle endurance tests significantly depended on the trunk extension muscle endurance before the intervention, and at 1 month (r = 0.723, p Pilates exercise program. At the end of the 16-week exercise program, cLBP intensity decreased by 2.01 ± 0.8 (p Pilates exercise program the pain intensified and the functional state deteriorated much faster than the maximum trunk muscle strength. Therefore, it can be concluded that, to decrease pain and improve functional condition, regular exercise (and not only improved strength and endurance) is required. We established that, although the 16-week lumbar stabilization exercise program increased isometric trunk extension and flexion strength and this increase in strength persisted for 2 months, decreased LBP and improved functional condition endured for only 1 month. Copyright © 2016 Elsevier Ltd. All rights reserved.

A flexoelectric theory with rotation gradient effects for elastic dielectrics

International Nuclear Information System (INIS)

Anqing, Li; Shenjie, Zhou; Lu, Qi; Xi, Chen

2016-01-01

In this paper, a general flexoelectric theory in the framework of couple stress theory is proposed for isotropic dielectrics, in which the rotation gradient and the polarization gradient are involved to represent the nonlocal mechanical and electrical effects, respectively. The present flexoelectric theory shows only the anti-symmetric part of rotation gradient can induce polarization, while the symmetric part of rotation gradient cannot induce polarization in isotropic dielectrics. The electrostatic stress is obtained naturally in the governing equations and boundary conditions in terms of the variational principle, which is composed of two parts: the Maxwell stress corresponding to the polarization and the remainder relating to the polarization gradient. The current theory is able to account for the effects of size, direct and inverse flexoelectricities, and electrostatic force. To illustrate this theory, a simple application of Bernoulli–Euler cantilever beam is discussed. The numerical results demonstrate neither the higher-order constant l 1 nor the higher-order constant l 2 associated with the symmetric and anti-symmetric parts of rotation gradient, respectively, can be ignored in the flexoelectric theory. In addition, the induced deflection increases as the increase of the flexoelectric coefficient. The polarization is no longer constant and the potential is no longer linear along the thickness direction of beam because of the influence of polarization gradient. (paper)

Isometric Shoulder Strength Reference Values for Physically Active Collegiate Males and Females

Science.gov (United States)

Westrick, Richard B.; Duffey, Michele L.; Cameron, Kenneth L.; Gerber, J. Parry; Owens, Brett D.

2013-01-01

Background: It is common clinical practice to assess muscle strength during examination of patients following shoulder injury or surgery. Strength comparisons are often made between the patient’s injured and uninjured shoulders, with the uninjured side used as a reference without regard to upper extremity dominance. Despite the importance of strength measurements, little is known about expected normal baselines of the uninjured shoulder. The purpose of this study was to report normative values for isometric shoulder strength for physically active college-age men and women without history of shoulder injury. Methods: University students—546 males (18.8 ± 1.0 years, 75.3 ± 12.2 kg) and 73 females (18.7 ± 0.9 years, 62.6 ± 7.0 kg)—underwent thorough shoulder evaluations by an orthopaedic surgeon and completed bilateral isometric strength measurements with a handheld dynamometer. Variables measured included internal rotation, external rotation, abduction, supine internal rotation and external rotation at 45°, and lower trapezius in prone flexion. Results: Significant differences were found between the dominant and nondominant shoulder for internal rotation, internal rotation at 45°, abduction, and prone flexion in males and in internal rotation at 45° and prone flexion for females (P ≤ 0.01). PMID:24381696

In vivo kinematics of healthy male knees during squat and golf swing using image-matching techniques.

Science.gov (United States)

Murakami, Koji; Hamai, Satoshi; Okazaki, Ken; Ikebe, Satoru; Shimoto, Takeshi; Hara, Daisuke; Mizu-uchi, Hideki; Higaki, Hidehiko; Iwamoto, Yukihide

2016-03-01

Participation in specific activities requires complex ranges of knee movements and activity-dependent kinematics. The purpose of this study was to investigate dynamic knee kinematics during squat and golf swing using image-matching techniques. Five healthy males performed squats and golf swings under periodic X-ray images at 10 frames per second. We analyzed the in vivo three-dimensional kinematic parameters of subjects' knees, namely the tibiofemoral flexion angle, anteroposterior (AP) translation, and internal-external rotation, using serial X-ray images and computed tomography-derived, digitally reconstructed radiographs. During squat from 0° to 140° of flexion, the femur moved about 25 mm posteriorly and rotated 19° externally relative to the tibia. Screw-home movement near extension, bicondylar rollback between 20° and 120° of flexion, and medial pivot motion at further flexion were observed. During golf swing, the leading and trailing knees (the left and right knees respectively in the right-handed golfer) showed approximately five millimeters and four millimeters of AP translation with 18° and 26° of axial rotation, respectively. A central pivot motion from set-up to top of the backswing, lateral pivot motion from top to ball impact, and medial pivot motion from impact to the end of follow-through were observed. The medial pivot motion was not always recognized during both activities, but a large range of axial rotation with bilateral condylar AP translations occurs during golf swing. This finding has important implications regarding the amount of acceptable AP translation and axial rotation at low flexion in replaced knees. IV. Copyright © 2015 Elsevier B.V. All rights reserved.

Design of a rotating-hearth furnace

Energy Technology Data Exchange (ETDEWEB)

Behrens, H A [Verein Deutscher Eisenhuettenleute (VDEh), Duesseldorf (Germany, F.R.)

1979-10-01

Presented in two parts, this paper is intended to provide an outline of the theoretical fundamentals for the design of rotating-hearth furnaces for heating round stock and deals with the characteristic design features of such furnaces.

The Arterial Folding Point During Flexion of the Hip Joint

International Nuclear Information System (INIS)

Park, Sung Il; Won, Je Hwan; Kim, Byung Moon; Kim, Jae Keun; Lee, Do Yun

2005-01-01

Purpose: Endovascular stents placed in periarticular vessels may be at a greater risk of neointimal hyperplasia and eventual occlusion than those placed in non-periarticular vessels. The purpose of this study was to investigate the location of maximal conformational change along the iliac and femoral artery, the folding point, during flexion of the hip joint and its location relative to the hip joint and the inguinal ligament. Methods: Seventy patients undergoing femoral artery catheterization were evaluated. The patients were 47 men and 23 women and ranged in age from 26 to 75 years (mean 54 years). The arteries (right:left = 34:36) were measured using a marked catheter for sizing vessels. Fluoroscopic images were obtained in anteroposterior and lateral projections in neutral position, and in the lateral projection in flexed position of the hip joint. The folding point was determined by comparing the lateral projection images in the neutral and flexed positions. The distance from the acetabular roof to the folding point and the distance from the inguinal ligament to the folding point was evaluated. Results: : The folding point was located 42.8 ± 28.6 mm cranial to the acetabular roof and 35.1 ± 30.1 mm cranial to the inguinal ligament. As the patient’s age increased, the folding point was located more cranially (p < 0.001). Conclusions: The folding point during flexion of the hip joint was located 42.8 ± 28.6 mm cranial to the acetabular roof and 35.1 ± 30.1 mm cranial to the inguinal ligament. As the patient's age increased, the folding point was located more cranially. When a stent is inserted over this region, more attention may be needed during follow-up to monitor possible occlusion and stent failure.

Sonographic measurements of the ulnar nerve at the elbow with different degrees of elbow flexion.

Science.gov (United States)

Patel, Prutha; Norbury, John W; Fang, Xiangming

2014-05-01

To determine whether there were differences in the cross-sectional area (CSA) and the flattening ratio of the normative ulnar nerve as it passes between the medial epicondyle and the olecranon at 30° of elbow flexion versus 90° of elbow flexion. Bilateral upper extremities of normal healthy adult volunteers were evaluated with ultrasound. The CSA and the flattening ratio of the ulnar nerve at the elbow as it passes between the medial epicondyle and the olecranon were measured, with the elbow flexed at 30° and at 90°, by 2 operators with varying ultrasound scanning experience by using ellipse and direct tracing methods. The results from the 2 different angles of elbow flexion were compared for each individual operator. Finally, intraclass correlations for absolute agreement and consistency between the 2 raters were calculated. An outpatient clinic room at a regional rehabilitation center. Twenty-five normal healthy adult volunteers. The mean CSA and the mean flattening ratio of the ulnar nerve at 30° of elbow flexion and at 90° of elbow flexion. First, for the ellipse method, the mean CSA of the ulnar nerve at 90° (9.93 mm(2)) was slightly larger than at 30° (9.77 mm(2)) for rater 1. However, for rater 2, the mean CSA of the ulnar nerve at 90° (6.80 mm(2)) was slightly smaller than at 30° (7.08 mm(2)). This was found to be statistically insignificant when using a matched pairs t test and the Wilcoxon signed-rank test, with a significance level of .05. Similarly, the difference between the right side and the left side was not statistically significant. The intraclass correlations for absolute agreement between the 2 raters were not very high due to different measurement locations, but the intraclass correlations for consistency were high. Second, for the direct tracing method, the mean CSA at 90° (7.26 mm(2)) was slightly lower than at 30° (7.48 mm(2)). This was found to be statistically nonsignificant when using the matched pairs t test and the

The Validity of a New Low-Dose Stereoradiography System to Perform 2D and 3D Knee Prosthetic Alignment Measurements.

Science.gov (United States)

Meijer, Marrigje F; Velleman, Ton; Boerboom, Alexander L; Bulstra, Sjoerd K; Otten, Egbert; Stevens, Martin; Reininga, Inge H F

2016-01-01

The EOS stereoradiography system has shown to provide reliable varus/valgus (VV) measurements of the lower limb in 2D (VV2D) and 3D (VV3D) after total knee arthroplasty (TKA). Validity of these measurements has not been investigated yet, therefore the purpose of this study was to determine validity of EOS VV2D and VV3D. EOS images were made of a lower limb phantom containing a knee prosthesis, while varying VV angle from 15° varus to 15° valgus and flexion angle from 0° to 20°, and changing rotation from 20° internal to 20° external rotation. Differences between the actual VV position of the lower limb phantom and its position as measured on EOS 2D and 3D images were investigated. Rotation, flexion or VV angle alone had no major impact on VV2D or VV3D. Combination of VV angle and rotation with full extension did not show major differences in VV2D measurements either. Combination of flexion and rotation with a neutral VV angle showed variation of up to 7.4° for VV2D; maximum variation for VV3D was only 1.5°. A combination of the three variables showed an even greater distortion of VV2D, while VV3D stayed relatively constant. Maximum measurement difference between preset VV angle and VV2D was 9.8°, while the difference with VV3D was only 1.9°. The largest differences between the preset VV angle and VV2D were found when installing the leg in extreme angles, for example 15° valgus, 20° flexion and 20° internal rotation. After TKA, EOS VV3D were more valid than VV2D, indicating that 3D measurements compensate for malpositioning during acquisition. Caution is warranted when measuring VV angle on a conventional radiograph of a knee with a flexion contracture, varus or valgus angle and/or rotation of the knee joint during acquisition.

MACULA: Fast Modeling of Rotational Modulations of Spotty Stars

Science.gov (United States)

Kipping, David

2015-08-01

Rotational modulations are frequently observed on stars observed by photometry surveys such as Kepler, with periodicities ranging from days to months and amplitudes of sub-parts-per-million to several percent. These variations may be studied to reveal important stellar properties such as rotational periods, inclinations and gradients of differential rotation. However, inverting the disk-integrated flux into a solution for spot number, sizes, contrasts, etc is highly degenerate and thereby necessitating an exhaustive search of the parameter space. In recognition of this, the software MACULA is designed to be a fast forward model of circular, grey spots on rotating stars, including effects such as differential rotation, spot evolution and even spot penumbra/umbra. MACULA seeks to achieve computational efficiency by using a wholly analytic description of the disk-integrated flux, which is described in Kipping (2012), leading to a computational improvement of three orders-of-magnitude over its numerical counterparts. As part of the hack day, I'll show how to simulate light curves with MACULA and provide examples with visualizations. I will also discuss the on-going development of the code, which will head towards modeling spot crossing events and radial velocity jitter and I encourage discussions amongst the participants on analytic methods to this end.

Stellar dynamism. Activity and rotation of solar stars observed from the Kepler satellite

International Nuclear Information System (INIS)

Ceillier, Tugdual

2015-01-01

This thesis concerns the study of seismic solar-like stars' rotation and magnetic activity. We use data from the Kepler satellite to study the rotational history of these stars throughout their evolution. This allows to have a more complete picture of stellar rotation and magnetism. In the first part, we present the context of this PhD: astro-seismology, the seismic study of stars. We continue by describing the tool we developed to measure surface rotation of stars using photometric data from Kepler. We compare it to other methodologies used by the community and show that its efficiency is very high. In the second part, we apply this tool to around 500 main-sequence and sub-giant solar-like stars. We measure surface rotation periods and activity levels for 300 of them. We show that the measured periods and the ages from astro-seismology do not agree well with the standard period-age relationships and propose to modify these relationships for stars older than the Sun. We also use the surface rotation as a constraint to estimate the internal rotation of a small number of seismic targets. We demonstrate that these stars have, like the Sun, a very low differential rotation ratio. In the third part, we apply our surface rotation-measuring tool to the most extensive sample of red giants observed by Kepler, comprising more than 17,000 stars. We identify more than 360 fast rotating red giants and compare our detection rates with the ones predicted by theory to better understand the reasons for this rapid rotation. We also use stellar modelling to reproduce the internal rotation profile of a particular red giant. This allows us to emphasize how important implementing new angular momentum transport mechanisms in stellar evolution codes is. This work offers new results that are useful to a very wide community of stellar physicists. It also puts strong constraints on the evolution of solar-like stars' rotation and magnetic activity. (author) [fr

Infrapatellar plica of the knee: Revisited with MR arthrographies undertaken in the knee flexion position mimicking operative arthroscopic posture

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Han; Song, Ho-Taek; Kim, Sungjun [Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Sung-Jae [Department of Orthopedic Surgery and Arthroscopic Surgery Unit, Yonsei University College of Medicine (Korea, Republic of); Suh, Jin-Suck, E-mail: jss@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

2012-10-15

Purpose: To describe the appearance of the infrapatellar plica (IPP) on magnetic resonance arthrography (MRA) taken in 70° knee flexion, corresponding to the arthroscopic posture. Materials and methods: Twenty-two patients (23 knee joints) who underwent MRA with 70° knee flexion were enrolled. All patients underwent MRA with 70° knee flexion to simulate operative arthroscopy. The images included fat-suppressed T1-weighted spin echo axial, sagittal, and coronal images. The visualization and morphology of the IPP were retrospectively assessed by two musculoskeletal radiologists. Results: The IPP was demonstrated in 78.3% (n = 18/23) and was best visualized on the sagittal section through the intercondylar notch. The IPP manifested as a linear hypointense structure with variable thicknesses. The intercondylar component was delineated clearly, arising from the anterior intercondylar notch in parallel with the ACL and curving gently downward to attach to the infrapatellar fat pad. On the other hand, the Hoffa's fat pad component was not depicted clearly. The morphology of the IPP was either a separate type (60.9%) or a split type (17.4%). Conclusion: The IPPs can be visualized with a high rate of detection and various morphologic appearances must be appreciated under the review of a flexed knee MRA.

International consensus on the most useful physical examination tests used by physiotherapists for patients with headache

DEFF Research Database (Denmark)

Luedtke, K; Boissonnault, W; Caspersen, Nina

2016-01-01

considered clinically useful: manual joint palpation, the cranio-cervical flexion test, the cervical flexion-rotation test, active range of cervical movement, head forward position, trigger point palpation, muscle tests of the shoulder girdle, passive physiological intervertebral movements, reproduction...

Fractal feature of sEMG from Flexor digitorum superficialis muscle correlated with levels of contraction during low-level finger flexions.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K; Naik, Ganesh R

2010-01-01

This research paper reports an experimental study on identification of the changes in fractal properties of surface Electromyogram (sEMG) with the changes in the force levels during low-level finger flexions. In the previous study, the authors have identified a novel fractal feature, Maximum fractal length (MFL) as a measure of strength of low-level contractions and has used this feature to identify various wrist and finger movements. This study has tested the relationship between the MFL and force of contraction. The results suggest that changes in MFL is correlated with the changes in contraction levels (20%, 50% and 80% maximum voluntary contraction (MVC)) during low-level muscle activation such as finger flexions. From the statistical analysis and by visualisation using box-plot, it is observed that MFL (p ≈ 0.001) is a more correlated to force of contraction compared to RMS (p≈0.05), even when the muscle contraction is less than 50% MVC during low-level finger flexions. This work has established that this fractal feature will be useful in providing information about changes in levels of force during low-level finger movements for prosthetic control or human computer interface.

Rotation in a gravitational billiard

Science.gov (United States)

Peraza-Mues, G. G.; Carvente, Osvaldo; Moukarzel, Cristian F.

Gravitational billiards composed of a viscoelastic frictional disk bouncing on a vibrating wedge have been studied previously, but only from the point of view of their translational behavior. In this work, the average rotational velocity of the disk is studied under various circumstances. First, an experimental realization is briefly presented, which shows sustained rotation when the wedge is tilted. Next, this phenomenon is scrutinized in close detail using a precise numerical implementation of frictional forces. We show that the bouncing disk acquires a spontaneous rotational velocity whenever the wedge angle is not bisected by the direction of gravity. Our molecular dynamics (MD) results are well reproduced by event-driven (ED) simulations. When the wedge aperture angle θW>π/2, the average tangential velocity Rω¯ of the disk scales with the typical wedge vibration velocity vb, and is in general a nonmonotonic function of the overall tilt angle θT of the wedge. The present work focuses on wedges with θW=2π/3, which are relevant for the problem of spontaneous rotation in vibrated disk packings. This study makes part of the PhD Thesis of G. G. Peraza-Mues.

Rotations in a Vertebrate Setting

Science.gov (United States)

McCollum, Gin

2003-05-01

Rotational movements of the head are often considered to be measured in a single three dimensional coordinate system implemented by the semicircular canals of the vestibular system of the inner ear. However, the vertebrate body -- including the nervous system -- obeys rectangular symmetries alien to rotation groups. At best, nervous systems mimic the physical rotation group in a fragmented way, only partially reintegrating physical movements in whole organism responses. The vestibular canal reference frame is widely used in nervous systems, for example by eye movements. It is used to some extent even in the cerebrum, as evidenced by the remission of hemineglect -- in which half of space is ignored -- when the vestibular system is stimulated. However, reintegration of space by the organism remains incomplete. For example, compensatory eye movements (which in most cases aid visual fixation) may disagree with conscious self-motion perception. In addition, movement-induced nausea, illusions, and cue-free perceptions demonstrate symmetry breaking or incomplete spatial symmetries. As part of a long-term project to investigate rotation groups in nervous systems, we have analyzed the symmetry group of a primary vestibulo-spinal projection.

Relationship between flexion contractures of the joints of the lower extremities and the sagittal profile of the spine in patients with cerebral palsy: a preliminary report

Directory of Open Access Journals (Sweden)

Valery V. Umnov

2016-11-01

Full Text Available Background. The considerable incidence of kyphosis in patients with cerebral palsy (CP causes back pain and aggravates movement disorders. However, few studies have investigated the pathogenesis of this condition. Aim. To identify the relationship between patient motor abilities, the severity of flexion contractures of the knee and hip joints and spinal sagittal profile changes, and the impact on the latter by surgical correction of flexion contracture of the knee joint. Material and methods. The study cohort included 17 pediatric CP patients (11 boys and 6 girls with a mean age of 13.1 ± 1.3 (range, 10–16 years and level 2–4 spastic diplegia according to the Gross Motor Function Classification System. The relationship between radiological indicators of the spine sagittal profile and motor abilities of children, as well as the severity of flexion contractures at the hip and knee, and the degree of insufficiency of the active extension of the knee were investigated. Of these 17 patients, 12 underwent surgery to correct flexion contracture of the knee, which involved lengthening of leg flexors, to analyze the impact of contracture on the sagittal profile of the spine. The following radiological indicators were assessed: angle of thoracic kyphosis (CC, lordosis angle (UL of the lumbar spine, and sacral inclination angle (SS. The study included patients with a CC of at least 30°. Results. Results of an X-ray study showed that the severity of kyphosis was 50.7° ± 2.1°, lordosis was 30.3° ± 4.3°, and SS was 30.5° ± 3.3°. There was a significant association between kyphosis and flexion contracture of the knee joint, as well as between lordosis and insufficient active extension of the knee joint. After elimination of the flexion contracture of the knee, the degree of severity of the CC (thoracic kyphosis was unchanged, while UL (lordosis angle and SS (sacral inclination angle increased by approximately 10°. Conclusion. The severity of

Increasing hip and knee flexion during a drop-jump task reduces tibiofemoral shear and compressive forces: implications for ACL injury prevention training.

Science.gov (United States)

Tsai, Liang-Ching; Ko, Yi-An; Hammond, Kyle E; Xerogeanes, John W; Warren, Gordon L; Powers, Christopher M

2017-12-01

Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10-15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI). Participants demonstrated a decrease in peak anterior tibial shear forces (11.1 ± 3.3 vs. 9.6 ± 2.7 N · kg -1 ; P = 0.008) and peak tibiofemoral compressive forces (68.4 ± 7.6 vs. 62.0 ± 5.5 N · kg -1 ; P = 0.015) post-training. The decreased peak anterior tibial shear was accompanied by a decrease in the quadriceps anterior shear force, while the decreased peak compressive force was accompanied by decreased ground reaction force and hamstring forces. Our data provide justification for injury prevention programmes that encourage greater hip and knee flexion during landing to reduce tibiofemoral joint loading.

Modelling of convective heat and mass transfer in rotating flows

CERN Document Server

Shevchuk, Igor V

2016-01-01

 This monograph presents results of the analytical and numerical modeling of convective heat and mass transfer in different rotating flows caused by (i) system rotation, (ii) swirl flows due to swirl generators, and (iii) surface curvature in turns and bends. Volume forces (i.e. centrifugal and Coriolis forces), which influence the flow pattern, emerge in all of these rotating flows. The main part of this work deals with rotating flows caused by system rotation, which includes several rotating-disk configurations and straight pipes rotating about a parallel axis. Swirl flows are studied in some of the configurations mentioned above. Curvilinear flows are investigated in different geometries of two-pass ribbed and smooth channels with 180° bends. The author demonstrates that the complex phenomena of fluid flow and convective heat transfer in rotating flows can be successfully simulated using not only the universal CFD methodology, but in certain cases by means of the integral methods, self-similar and analyt...

Mental rotation and the motor system: embodiment head over heels.

Science.gov (United States)

Krüger, Markus; Amorim, Michel-Ange; Ebersbach, Mirjam

2014-01-01

We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N=30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N=32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance. Copyright © 2013 Elsevier B.V. All rights reserved.

Is digital photography an accurate and precise method for measuring range of motion of the shoulder and elbow?

Science.gov (United States)

Russo, Russell R; Burn, Matthew B; Ismaily, Sabir K; Gerrie, Brayden J; Han, Shuyang; Alexander, Jerry; Lenherr, Christopher; Noble, Philip C; Harris, Joshua D; McCulloch, Patrick C

2018-03-01

Accurate measurements of shoulder and elbow motion are required for the management of musculoskeletal pathology. The purpose of this investigation was to compare three techniques for measuring motion. The authors hypothesized that digital photography would be equivalent in accuracy and show higher precision compared to the other two techniques. Using infrared motion capture analysis as the reference standard, shoulder flexion/abduction/internal rotation/external rotation and elbow flexion/extension were measured using visual estimation, goniometry, and digital photography on 10 fresh frozen cadavers. These measurements were performed by three physical therapists and three orthopaedic surgeons. Accuracy was defined by the difference from the reference standard (motion capture analysis), while precision was defined by the proportion of measurements within the authors' definition of clinical significance (10° for all motions except for elbow extension where 5° was used). Analysis of variance (ANOVA), t-tests, and chi-squared tests were used. Although statistically significant differences were found in measurement accuracy between the three techniques, none of these differences met the authors' definition of clinical significance. Precision of the measurements was significantly higher for both digital photography (shoulder abduction [93% vs. 74%, p < 0.001], shoulder internal rotation [97% vs. 83%, p = 0.001], and elbow flexion [93% vs. 65%, p < 0.001]) and goniometry (shoulder abduction [92% vs. 74%, p < 0.001] and shoulder internal rotation [94% vs. 83%, p = 0.008]) than visual estimation. Digital photography was more precise than goniometry for measurements of elbow flexion only [93% vs. 76%, p < 0.001]. There was no clinically significant difference in measurement accuracy between the three techniques for shoulder and elbow motion. Digital photography showed higher measurement precision compared to visual estimation for shoulder abduction, shoulder

Free Biceps Tendon Autograft to Augment Arthroscopic Rotator Cuff Repair

OpenAIRE

Obma, Padraic R.

2013-01-01

Arthroscopic rotator cuff repairs have become the standard of treatment for all sizes of tears over the past several years. Current healing rates reported in the literature are quite good, but improving the healing potential of rotator cuff repairs remains a challenging problem. There has been an increase recently in the use of augmentation of rotator cuff repairs with xenografts or synthetics for large and massive tears. Biceps tenodesis is often indicated as part of the treatment plan while...

Some geometrical problems related to the rotation camera. Pt. 1

International Nuclear Information System (INIS)

Taupin, D.

1985-01-01

An algorithm for a safe generation of the table of expected reflections in the Arndt-Wonnacott rotation camera is given. It relies upon classic quadratic matrixalgebra. Some mathematical theorems are recalled. This algorithm is part of a series of programs developed at Orsay for the treatment of rotation-camera photographs. (orig.)

Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles.

Science.gov (United States)

Rui, Yongjun; Pan, Feng; Mi, Jingyi

2016-10-01

The rat is a suitable model to study human rotator cuff pathology owing to the similarities in morphological anatomy structure. However, few studies have reported the composition muscle fiber types of rotator cuff muscles in the rat. In this study, the myosin heavy chain (MyHC) isoforms were stained by immunofluorescence to show the muscle fiber types composition and distribution in rotator cuff muscles of the rat. It was found that rotator cuff muscles in the rat were of mixed fiber type composition. The majority of rotator cuff fibers labeled positively for MyHCII. Moreover, the rat rotator cuff muscles contained hybrid fibers. So, compared with human rotator cuff muscles composed partly of slow-twitch fibers, the majority of fast-twitch fibers in rat rotator cuff muscles should be considered when the rat model study focus on the pathological process of rotator cuff muscles after injury. Gaining greater insight into muscle fiber types in rotator cuff muscles of the rat may contribute to elucidate the mechanism of pathological change in rotator cuff muscles-related diseases. Anat Rec, 299:1397-1401, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effects of knee extension constraint training on knee flexion angle and peak impact ground-reaction force.

Science.gov (United States)

Liu, Hui; Wu, Will; Yao, Wanxiang; Spang, Jeffrey T; Creighton, R Alexander; Garrett, William E; Yu, Bing

2014-04-01

Low compliance with training programs is likely to be one of the major reasons for inconsistency of the data regarding the effectiveness of current anterior cruciate ligament (ACL) injury prevention programs. Training methods that reduce training time and cost could favorably influence the effectiveness of ACL injury prevention programs. A newly designed knee extension constraint training device may serve this purpose. (1) Knee extension constraint training for 4 weeks would significantly increase the knee flexion angle at the time of peak impact posterior ground-reaction force and decrease peak impact ground-reaction forces during landing of a stop-jump task and a side-cutting task, and (2) the training effects would be retained 4 weeks after completion of the training program. Controlled laboratory study. Twenty-four recreational athletes were randomly assigned to group A or B. Participants in group A played sports without wearing a knee extension constraint device for 4 weeks and then played sports while wearing the device for 4 weeks, while participants in group B underwent a reversed protocol. Both groups were tested at the beginning of week 1 and at the ends of weeks 4 and 8 without wearing the device. Knee joint angles were obtained from 3-dimensional videographic data, while ground-reaction forces were measured simultaneously using force plates. Analyses of variance were performed to determine the training effects and the retention of training effects. Participants in group A significantly increased knee flexion angles and decreased ground-reaction forces at the end of week 8 (P ≤ .012). Participants in group B significantly increased knee flexion angles and decreased ground-reaction forces at the ends of weeks 4 and 8 (P ≤ .007). However, participants in group B decreased knee flexion angles and increased ground-reaction forces at the end of week 8 in comparison with the end of week 4 (P ≤ .009). Knee extension constraint training for 4 weeks

In-situ mechanical behavior and slackness of the anterior cruciate ligament at multiple knee flexion angles

NARCIS (Netherlands)

Rachmat, H.H.; Janssen, D.W.; Verkerke, G.J.; Diercks, R.L.; Verdonschot, N.J.J.

2016-01-01

In this study the in-situ tensile behavior and slackness of the anterior cruciate ligament (ACL) was evaluated at various knee flexion angles. In four cadaveric knees the ACL was released at the tibial insertion, after which it was re-connected to a tensiometer. After pre-tensioning (10 N) the ACL

Stress changes of lateral collateral ligament at different

Directory of Open Access Journals (Sweden)

ZHONG Yan-lin

2011-04-01

Full Text Available 【Abstract】 Objective: To create a 3-dimensional finite element model of knee ligaments and to analyse the stress changes of lateral collateral ligament (LCL with or without displaced movements at different knee flexion conditions. Methods: A four-major-ligament contained knee specimen from an adult died of skull injury was prepared for CT scanning with the detectable ligament insertion footprints, locations and orientations precisely marked in advance. The CT scanning images were converted to a 3-dimensional model of the knee with the 3-dimensional reconstruction technique and transformed into finite element model by the software of ANSYS. The model was validated using experimental and numerical results obtained by other scientists. The natural stress changes of LCL at five different knee flexion angles (0°, 30°, 60°, 90°, 120° and under various motions of anterior-posterior tibial translation, tibial varus rotation and internal-external tibial rotation were measured. Results: The maximum stress reached to 87%-113% versus natural stress in varus motion at early 30° of knee flexions. The stress values were smaller than the peak value of natural stress at 0° (knee full extension when knee bending was over 60° of flexion in anterior-posterior tibial translation and internal-external rotation. Conclusion: LCL is vulnerable to varus motion in almost all knee bending positions and susceptible to anterior- posterior tibial translation or internal-external rotation at early 30° of knee flexions. Key words: Knee joint; Collateral ligaments; Finite element analysis

Rotator cuff ruptures of the shoulder joint, sonography - arthrography

International Nuclear Information System (INIS)

Triebel, H.J.; Wening, V.; Witte, G.; Hamburg Univ.

1986-01-01

47 patients suspected of rutpure of the rotator cuff were sonographed and arthrographed. Rupture of the rotator cuff was diagnosed in 12 cases, both diagnostic methods yielding the same result. In 29 patients sonography and arthrography did not reveal any abnormal findings. Six ruptures evident in sonography were not confirmed by arthrography and were considered false positive. Direct pointers towards rupture of the cuff would be: echoless defects, cuff cannot be visualised fully or in part and irregularities of movement during dynamic examination. Echoless 'cystic' areas in the periarticular soft parts must be considered an indirect pointer. Echorich focal findings in the echopoor cuff represent a differential diagnostic problem and we cannot give a final assessment as yet. Shoulder sonography is justified as a screening method in suspicion of rotator cuff rupture before initiating arthrography. If sonography reveals no abnormal findings, shoulder arthrography need not be performed. (orig.) [de

Effect of static and dynamic muscle stretching as part of warm up procedures on knee joint proprioception and strength.

Science.gov (United States)

Walsh, Gregory S

2017-10-01

The importance of warm up procedures prior to athletic performance is well established. A common component of such procedures is muscle stretching. There is conflicting evidence regarding the effect of static stretching (SS) as part of warm up procedures on knee joint position sense (KJPS) and the effect of dynamic stretching (DS) on KJPS is currently unknown. The aim of this study was to determine the effect of dynamic and static stretching as part warm up procedures on KJPS and knee extension and flexion strength. This study had a randomised cross-over design and ten healthy adults (20±1years) attended 3 visits during which baseline KJPS, at target angles of 20° and 45°, and knee extension and flexion strength tests were followed by 15min of cycling and either a rest period (CON), SS, or DS and repeat KJPS and strength tests. All participants performed all conditions, one condition per visit. There were warm up×stretching type interactions for KJPS at 20° (p=0.024) and 45° (p=0.018), and knee flexion (p=0.002) and extension (pwarm up procedures. However, the negative impact of SS on muscle strength limits the utility of SS before athletic performance. If stretching is to be performed as part of a warm up, DS should be favoured over SS. Copyright © 2017 Elsevier B.V. All rights reserved.

New Design of a Soft Robotics Wearable Elbow Exoskeleton Based on Shape Memory Alloy Wire Actuators

Directory of Open Access Journals (Sweden)

Dorin Copaci

2017-01-01

Full Text Available The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement and the proximal radioulnar articulation (for pronation-supination movement. During the flexion-extension movement of the elbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal of this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for flexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions, which align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a comfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid parts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low noise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical rehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these diseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to evaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis.

New Design of a Soft Robotics Wearable Elbow Exoskeleton Based on Shape Memory Alloy Wire Actuators

Science.gov (United States)

Cano, Enrique; Moreno, Luis; Blanco, Dolores

2017-01-01

The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement) and the proximal radioulnar articulation (for pronation-supination movement). During the flexion-extension movement of the elbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal of this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for flexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions, which align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a comfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid parts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low noise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical rehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these diseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to evaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis. PMID:29104424

New Design of a Soft Robotics Wearable Elbow Exoskeleton Based on Shape Memory Alloy Wire Actuators.

Science.gov (United States)

Copaci, Dorin; Cano, Enrique; Moreno, Luis; Blanco, Dolores

2017-01-01

The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement) and the proximal radioulnar articulation (for pronation-supination movement). During the flexion-extension movement of the elbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal of this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for flexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions, which align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a comfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid parts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low noise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical rehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these diseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to evaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis.

Wave-driven Rotation in Supersonically Rotating Mirrors

Energy Technology Data Exchange (ETDEWEB)

A. Fetterman and N.J. Fisch

2010-02-15

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Wave-driven Rotation in Supersonically Rotating Mirrors

International Nuclear Information System (INIS)

Fetterman, A.; Fisch, N.J.

2010-01-01

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Pilot study of impedance-controlled microcurrent therapy for managing radiation-induced fibrosis in head-and-neck cancer patients

International Nuclear Information System (INIS)

Lennox, Arlene J.; Shafer, Jeffrey P.; Hatcher, Madeline; Beil, Janice; Funder, Sandra J.

2002-01-01

Purpose: To evaluate the effectiveness of impedance-controlled microcurrent therapy for managing treatment sequelae in head-and-neck cancer patients. Methods and Materials: Between January 1998 and June 1999, 26 patients who were experiencing late effects of radiotherapy were treated b.i.d. with impedance-controlled microcurrent therapy for 1 week. Objective range-of-motion measurements were made for cervical rotation, extension/flexion, and lateral flexion before therapy, at the end of each treatment day, and monthly for 3 months. In addition, each patient's subjective complaints were tabulated before treatment and reevaluated at the last follow-up visit. No additional physical therapy or electrical stimulation was permitted during the follow-up period. Results: At the end of the course of microcurrent therapy, 92% of the 26 patients exhibited improved cervical rotation, 85% had improved cervical extension/flexion, and 81% had improved cervical lateral flexion. Twenty-two patients returned for the 3-month follow-up visit. Of these, 91% had maintained a cervical rotation range of motion greater than their pretherapy measurements. Eighty-two percent maintained improved cervical extension/flexion and 77% maintained improved lateral flexion. When the range-of-motion measurements were stratified by pretreatment severity (severe, moderate, mild, or asymptomatic), the degree of improvement directly correlated with the severity. Thus, patients who had more severe initial symptoms experienced a higher percentage of improvement than did those with milder symptoms. For these patients, the cervical rotation range of motion changed from a baseline of 59 deg. ± 12 deg. to 83 deg. ± 14 deg. at 3 months; flexion/extension improved from 47 deg. ± 10 deg. to 73 deg. ± 13 deg.; and lateral flexion went from 31 deg. ± 7 deg. to 48 deg. ± 9 deg. Some patients also reported symptom improvement for tongue mobility, facial asymmetry, xerostomia, cervical/facial muscle spasms

Electromagnetic fields of rotating magnetized NUT stars

International Nuclear Information System (INIS)

Ahmedov, B.J.; Khugaev, A.V.; Ahmedov, B.J.

2004-01-01

Full text: Analytic general relativistic expressions for the electromagnetic fields external to a slowly-rotating magnetized NUT star with nonvanishing gravitomagnetic charge have been presented. Solutions for the electric and magnetic fields have been found after separating the Maxwell equations in the external background spacetime of a slowly rotating NUT star into angular and radial parts in the lowest order approximation. The star is considered isolated and in vacuum, with different models for stellar magnetic field: i) monopolar magnetic field and II) dipolar magnetic field aligned with the axis of rotation. We have shown that the general relativistic corrections due to the dragging of reference frames and gravitomagnetic charge are not present in the form of the magnetic fields but emerge only in the form of the electric fields. In particular, we have shown that the frame-dragging and gravitomagnetic charge provide an additional induced electric field which is analogous to the one introduced by the rotation of the star in the flat spacetime limit

Should a clinical rotation in hematology be mandatory for undergraduate medical students?

Directory of Open Access Journals (Sweden)

Mandan J

2016-09-01

Full Text Available Jay Mandan,1 Harmeet Singh Sidhu,1 Adil Mahmood2 1Faculty of Medicine, Imperial College London, London, UK; 2Faculty of Life Sciences and Medicine, King’s College London, London, UK Abstract: Clinical rotations form the foundation of medical education. Medical students in the UK are offered conventional rotations such as cardiology, surgery, and psychiatry as part of their undergraduate curriculum, but a rotation in hematology is not currently mandatory. This paper explores the benefits of a compulsory hematology rotation, and suggests recommendations for its implementation in UK medical school curricula. Keywords: medical education, clinical rotations, hematology

Rotating flow

CERN Document Server

Childs, Peter R N

2010-01-01

Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

Effect of cranial cruciate ligament deficiency, tibial plateau leveling osteotomy, and tibial tuberosity advancement on contact mechanics and alignment of the stifle in flexion.

Science.gov (United States)

Kim, Stanley E; Pozzi, Antonio; Banks, Scott A; Conrad, Bryan P; Lewis, Daniel D

2010-04-01

To assess contact mechanics and 3-dimensional (3-D) joint alignment in cranial cruciate ligament (CCL)-deficient stifles before and after tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA) with the stifle in 90 degrees of flexion. In vitro biomechanical study. Cadaveric pelvic limb pairs (n=8) from dogs weighing 28-35 kg. Contralateral limbs were assigned to receive TPLO or TTA. Digital pressure sensors were used to measure femorotibial contact area, peak and mean contact pressure, and peak pressure location with the limb under a load of 30% body weight and stifle flexion angle of 90 degrees . 3-D poses were obtained using a Microscribe digitizer. Specimens were tested under normal, CCL deficient, and treatment conditions. Significant disturbances in alignment were not observed after CCL transection, although medial contact area was 10% smaller than normal (P=.003). There were no significant differences in contact mechanics or alignment between normal and TTA conditions; TPLO induced 6 degrees varus angulation (PCranial tibial subluxation is nominal in CCL-deficient stifles loaded in flexion. Stifle alignment and contact mechanics are not altered by TTA, whereas TPLO causes mild varus and a subsequent increase in medial compartment loading. Cranial tibial subluxation of CCL-deficient stifles may not occur during postures that load the stifle in flexion. The significance of minor changes in loading patterns after TPLO is unknown.

The role of the faceguard in the production of flexion injuries to the cervical spine in football.

Science.gov (United States)

Melvin, W J; Dunlop, H W; Hetherington, R F; Kerr, J W

1965-11-20

The precise role of the single-bar face mask in producing major flexion violence to the cervical spine has been studied by review of game movies, analysis of the radiographs and detailed interviews with two players who sustained fractures of cervical spine. The single-bar face mask can become fixed in the ground, thereby forcing a runner's head down onto his chest as the trunk moves forward. Preventive measures embodying modifications in the face mask, strict coaching in football techniques and the institution of safety factors in the playing rules are proposed. Appreciation of the mechanism of injury is urged in order to encourage careful inspection of protective head gear as well as to direct the attention of team physicians to the possibility of serious flexion injury to the cervical spine occurring without dramatic evidence. This report is not a plea for abandonment of the face mask but rather a suggestion for careful selection of a safe and efficient mask.

A Pilot Study of Individual Muscle Force Prediction during Elbow Flexion and Extension in the Neurorehabilitation Field

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Jiateng Hou

2016-11-01

Full Text Available This paper proposes a neuromusculoskeletal (NMS model to predict individual muscle force during elbow flexion and extension. Four male subjects were asked to do voluntary elbow flexion and extension. An inertial sensor and surface electromyography (sEMG sensors were attached to subject's forearm. Joint angle calculated by fusion of acceleration and angular rate using an extended Kalman filter (EKF and muscle activations obtained from the sEMG signals were taken as the inputs of the proposed NMS model to determine individual muscle force. The result shows that our NMS model can predict individual muscle force accurately, with the ability to reflect subject-specific joint dynamics and neural control solutions. Our method incorporates sEMG and motion data, making it possible to get a deeper understanding of neurological, physiological, and anatomical characteristics of human dynamic movement. We demonstrate the potential of the proposed NMS model for evaluating the function of upper limb movements in the field of neurorehabilitation.

Orientation of axes in the elbow and forearm for biomechanical modelling

NARCIS (Netherlands)

Veeger, H. E J; Yu, B.

1996-01-01

To determine the three-dimensional positions and orientations of axes of rotation for elbow flexion and forearm prosupination, the flexion-extension and prosupination movements were measured for five arms. Four right and one arm were taken from four fresh cadavers. Movement was measured with a

Postoperative stability of 2-jaw surgery with clockwise rotation of the occlusal plane.

Science.gov (United States)

Bang, Sung-Moon; Kwon, Yong-Dae; Kim, Su-Jung; Lee, Baek-Soo; Choi, Byung-Joon; Ohe, Joo-Young; Suh, Joon-Ho

2012-03-01

The objective of this study was to investigate the skeletal stability after Le Fort I osteotomy with clockwise rotation and bilateral sagittal split osteotomy. The sample consisted of 31 young Korean patients who were treated with Le Fort I osteotomy with clockwise rotation and setback bilateral sagittal split osteotomy. The lateral cephalographs were obtained before surgery (T1), right after surgery (T2), and on an average of 6.23 months after the operation (T3). The horizontal and vertical relations of landmarks to the reference line and soft tissue changes were evaluated. During the T2 - T1 period, there was superior and anterior movement of the posterior part (PNS, UMD) and advancement and impaction of the anterior part (ANS, A point, UIE) of the maxilla. The mandible was moved superiorly and posteriorly. During the T3 - T2 period, maxillary segment showed counterclockwise rotational relapse. The posterior part was relatively stable especially in the vertical position and the anterior part moved in the posterior and superior directions. Mandibular landmarks showed forward relapse in the horizontal aspect and superior relapse in the vertical aspect. The posterior part (PNS and UMD) showed a significantly higher stability rate (>70%) in the vertical aspect and the anterior part of the maxilla (ANS, A point) demonstrated a significantly lower value (occlusal plane showed stable results especially in the maxillary posterior landmarks. The clockwise rotational movement can be beneficial to increase skeletal stability and facial aesthetics in Asians.

Cementless anatomical prosthesis for the treatment of 3-part and 4-part proximal humerus fractures: cadaver study and prospective clinical study with minimum 2 years followup

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Obert Laurent

2016-01-01

Full Text Available Introduction: The purpose of this study was to evaluate the functional and radiological outcomes of a cementless, trauma-specific locked stem for 3- and 4-part proximal humeral fractures. Materials and methods: This study consisted of two parts: a cadaver study with 22 shoulders and a multicenter prospective clinical study of 23 fracture patients evaluated at least 2 years after treatment. In the cadaver study, the locked stem (HumelockTM, FX Solutions and its instrumentation were evaluated. In the clinical study, five senior surgeons at four different hospitals performed the surgical procedures. An independent surgeon evaluated the patients using clinical (Constant score, QuickDASH and radiological (X-rays, CT scans outcome measures. Results: The cadaver study allowed us to validate the height landmarks relative to the pectoralis major tendon. In the clinical study, at the review, abduction was 95° (60–160, forward flexion was 108° (70–160, external rotation (elbow at body was 34° (0–55, the QuickDASH was 31 (4.5–59, the overall Constant score was 54 (27–75, and the weighted Constant score was 76 (31.5–109. Discussion: This preliminary study of hemiarthroplasty (HA with a locked stem found results that were at least equivalent to published series. As all patients had at least a 2-year follow-up, integration of the locked stem did not cause any specific complications. These results suggest that it is possible to avoid using cement when hemiarthroplasty is performed for the humeral stem. This implant makes height adjustment and transosseous suturing of the tuberosities more reproducible.

Kinematics and load-sharing of an anterior thoracolumbar spinal reconstruction construct with PEEK rods: An in vitro biomechanical study.

Science.gov (United States)

Zhou, Ruozhou; Huang, Zhiping; Liu, Xiang; Tong, Jie; Ji, Wei; Liu, Sheting; Zhu, Qingan

2016-12-01

Polyetheretherketone rod constructs provide adequate spinal stability. Kinematics and load sharing of anterior thoracolumbar reconstruction with polyetheretherketone rods under preload remains unknown. Eight human cadaveric specimens (T11-L3) were subjected to a pure moment of 5.0Nm in flexion-extension, lateral bending and axial rotation, and flexion-extension with a compressive preload of 300N. An anterior reconstruction of L1 corpectomy was conducted with a surrogate bone graft and anterior rod constructs (polyetheretherketone or titanium rods). An axial load-cell was built in the surrogate bone graft to measure the compressive force in the graft. Range of motion, neutral zone and compressive force in the graft were compared between constructs. The polyetheretherketone rod construct resulted in more motion than the titanium rod construct, particularly in extension (P=0.011) and axial rotation (P=0.001), but less motion than the intact in all directions except in axial rotation. There was no difference in range of motion or neutral zone between constructs in flexion-extension under preload. The polyetheretherketone rod construct kept the graft compressed 52N which was similar to the titanium rod construct (63N), but allowed the graft compressed more under the preload (203N vs. 123N, P=0.003). The compressive forces fluctuated in flexion-extension without preload, but increased in flexion and decreased in extension under preload. The polyetheretherketone rod construct allowed more motion compared to the titanium rod construct, but provided stability in flexion and lateral bending without preload, and flexion and extension under preload. The anterior graft shared higher load under preload, particularly for the polyetheretherketone rod construct. The results of this study suggest that rigidity of rods in the anterior reconstruction affects kinematic behavior and load sharing. Copyright © 2016 Elsevier Ltd. All rights reserved.

High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: results of a prospective cohort study.

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Hoogendoorn, W E; Bongers, P M; de Vet, H C W; Ariëns, G A M; van Mechelen, W; Bouter, L M

2002-05-01

To determine whether physical and psychosocial load at work influence sickness absence due to low back pain. The research was a part of the study on musculoskeletal disorders, absenteeism, stress, and health (SMASH), a 3 year prospective cohort study on risk factors for musculoskeletal disorders. Workers from 21 companies located throughout The Netherlands participated in the part of this study on sickness absence due to low back pain. The study population consisted of 732 workers with no sickness absences of 3 days or longer due to low back pain in the 3 months before the baseline survey and complete data on the reasons for absences during the follow up period. The mean (range) period of follow up in this group was 37 (7-44) months. Physical load at work was assessed by analyses of video recordings. Baseline information on psychosocial work characteristics was obtained by a questionnaire. Data on sickness absence were collected from company records. The main outcome measure was the rate of sickness absences of 3 days or longer due to low back pain during the follow up period. After adjustment of the work related physical and psychosocial factors for each other and for other potential determinants, significant rate ratios ranging from 2.0 to 3.2 were found for trunk flexion, trunk rotation, lifting, and low job satisfaction. A dose-response relation was found for trunk flexion, but not for trunk rotation or lifting. Non-significant rate ratios of about 1.4 were found for low supervisor support and low coworker support. Quantitative job demands, conflicting demands, decision authority, and skill discretion showed no relation with sickness absence due to low back pain. Flexion and rotation of the trunk, lifting, and low job satisfaction are risk factors for sickness absence due to low back pain. Some indications of a relation between low social support, either from supervisors or coworkers, and sickness absence due to low back pain are also present.

Rotational Seismology: AGU Session, Working Group, and Website

Science.gov (United States)

Lee, William H.K.; Igel, Heiner; Todorovska, Maria I.; Evans, John R.

2007-01-01

Introduction Although effects of rotational motions due to earthquakes have long been observed (e. g., Mallet, 1862), nevertheless Richter (1958, p. 213) stated that: 'Perfectly general motion would also involve rotations about three perpendicular axes, and three more instruments for these. Theory indicates, and observation confirms, that such rotations are negligible.' However, Richter provided no references for this claim. Seismology is based primarily on the observation and modeling of three-component translational ground motions. Nevertheless, theoretical seismologists (e.g., Aki and Richards, 1980, 2002) have argued for decades that the rotational part of ground motions should also be recorded. It is well known that standard seismometers are quite sensitive to rotations and therefore subject to rotation-induced errors. The paucity of observations of rotational motions is mainly the result of a lack, until recently, of affordable rotational sensors of sufficient resolution. Nevertheless, in the past decade, a number of authors have reported direct observations of rotational motions and rotations inferred from rigid-body rotations in short baseline accelerometer arrays, creating a burgeoning library of rotational data. For example, ring laser gyros in Germany and New Zealand have led to the first significant and consistent observations of rotational motions from distant earthquakes (Igel et al., 2005, 2007). A monograph on Earthquake Source Asymmetry, Structural Media and Rotation Effects was published recently as well by Teisseyre et al. (2006). Measurement of rotational motions has implications for: (1) recovering the complete ground-displacement history from seismometer recordings; (2) further constraining earthquake rupture properties; (3) extracting information about subsurface properties; and (4) providing additional ground motion information to earthquake engineers for seismic design. A special session on Rotational Motions in Seismology was convened by H

Is rotating between static and dynamic work beneficial for our fatigue state?

NARCIS (Netherlands)

Luger, T.; Bosch, T.; Hoozemans, M.J.M.; Veeger,D.H.E.J.; Looze, M.P. de

2016-01-01

Shoulder disorders comprise a large part of work-related musculoskeletal disorders. Risk factors, such as repetitiveness and monotony, may cause muscle fatigue and be attenuated by task rotation. We investigated rotation between a dynamic box-lifting task and a relatively static pick-and-place task

How much vertical displacement of the symphysis indicates instability after pelvic injury?

Science.gov (United States)

Golden, Robert D; Kim, Hyunchul; Watson, Jeffrey D; Oliphant, Bryant W; Doro, Christopher; Hsieh, Adam H; Osgood, Greg M; O'Toole, Robert V

2013-02-01

Measures of pubic symphyseal widening are used by at least two classification systems as determinants of injury grade. Recent work has challenged the commonly used parameter of 2.5 cm of pubic symphysis as an accurate marker of pelvic injury grade and has suggested a role of rotation in the flexion-extension plane as a determinant of pelvic stability. We investigated pelvic stability in the flexion-extension plane to determine a threshold of rotational displacement of the hemipelvis above which the potential for instability exists. Cadaveric specimens were mounted onto a servohydraulic biaxial testing machine and subjected to a vertically directed flexion moment. Position of hemipelvis was recorded using a three-dimensional motion capture system and video recording. Displacement of the pubic symphysis and changes in length and position of the sacrospinous and sacrotuberous ligaments were recorded. Amount of force applied was measured and recorded. A yield point was determined as the first point at which the force plot exhibited a decrease in force and was correlated to the corresponding displacement. The mean vertical displacement of the pubic symphysis at the yield point was 16 mm (95% confidence interval, 11-22 mm). Mean sacrospinous ligament strain at yield point was 4% (range, 1.0-9.5%). Pelves with vertical rotational symphyseal displacement of less than 11 mm can reasonably be expected to have rotational stability in the flexion-extension plane. Those with displacement of greater than 22 mm can be expected to have lost some integrity regarding resistance to pelvic flexion. These values may allow clinicians to infer pelvic stability from amount of vertical symphyseal displacement.

The role of sea-ice albedo in the climate of slowly rotating aquaplanets

Science.gov (United States)

Salameh, Josiane; Popp, Max; Marotzke, Jochem

2018-04-01

We investigate the influence of the rotation period (P_{rot}) on the mean climate of an aquaplanet, with a focus on the role of sea-ice albedo. We perform aquaplanet simulations with the atmospheric general circulation model ECHAM6 for various rotation periods from one Earth-day to 365 Earth-days in which case the planet is synchronously rotating. The global-mean surface temperature decreases with increasing P_{rot} and sea ice expands equatorwards. The cooling of the mean climate with increasing P_{rot} is caused partly by the high surface albedo of sea ice on the dayside and partly by the high albedo of the deep convective clouds over the substellar region. The cooling caused by these deep convective clouds is weak for non-synchronous rotations compared to synchronous rotation. Sensitivity simulations with the sea-ice model switched off show that the global-mean surface temperature is up to 27 K higher than in our main simulations with sea ice and thus highlight the large influence of sea ice on the climate. We present the first estimates of the influence of the rotation period on the transition of an Earth-like climate to global glaciation. Our results suggest that global glaciation of planets with synchronous rotation occurs at substantially lower incoming solar irradiation than for planets with slow but non-synchronous rotation.

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion.

Science.gov (United States)

Kerkum, Yvette L; Buizer, Annemieke I; van den Noort, Josien C; Becher, Jules G; Harlaar, Jaap; Brehm, Merel-Anne

2015-01-01

Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (ppush-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power. Dutch Trial Register NTR3418.

Shoulder rotator isokinetic strength profile in young swimmers. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n5p545

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Pablo Tomas-Carus

2012-09-01

Full Text Available Considering that some studies suggest that shoulder rotators muscle imbal­ances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i to describe the muscle balance, fatigue and isokinetic strength profile of the shoulder rotators in young swimmers; ii to compare the results between swimmers and a group of young non-practitioners; iii to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg. The evaluation was performed in the sitting position (90° abduction and elbow flexion at 60º.s-1 and 180º.s-1 angular speeds using an isokinetic dynamometer (Biodex System 3. The results of the fatigue ratios revealed no differences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL and 77.89 ± 15,23% in the non-dominant limb (NDL for assessments at 60º.s-1. At 180º.s-1, ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and differed from non-practitioners in the ability to produce power with the internal rotators, which was significantly higher in the former group.

The Validity of a New Low-Dose Stereoradiography System to Perform 2D and 3D Knee Prosthetic Alignment Measurements.

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Marrigje F Meijer

Full Text Available The EOS stereoradiography system has shown to provide reliable varus/valgus (VV measurements of the lower limb in 2D (VV2D and 3D (VV3D after total knee arthroplasty (TKA. Validity of these measurements has not been investigated yet, therefore the purpose of this study was to determine validity of EOS VV2D and VV3D.EOS images were made of a lower limb phantom containing a knee prosthesis, while varying VV angle from 15° varus to 15° valgus and flexion angle from 0° to 20°, and changing rotation from 20° internal to 20° external rotation. Differences between the actual VV position of the lower limb phantom and its position as measured on EOS 2D and 3D images were investigated.Rotation, flexion or VV angle alone had no major impact on VV2D or VV3D. Combination of VV angle and rotation with full extension did not show major differences in VV2D measurements either. Combination of flexion and rotation with a neutral VV angle showed variation of up to 7.4° for VV2D; maximum variation for VV3D was only 1.5°. A combination of the three variables showed an even greater distortion of VV2D, while VV3D stayed relatively constant. Maximum measurement difference between preset VV angle and VV2D was 9.8°, while the difference with VV3D was only 1.9°. The largest differences between the preset VV angle and VV2D were found when installing the leg in extreme angles, for example 15° valgus, 20° flexion and 20° internal rotation.After TKA, EOS VV3D were more valid than VV2D, indicating that 3D measurements compensate for malpositioning during acquisition. Caution is warranted when measuring VV angle on a conventional radiograph of a knee with a flexion contracture, varus or valgus angle and/or rotation of the knee joint during acquisition.

Global rotation

International Nuclear Information System (INIS)

Rosquist, K.

1980-01-01

Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

Modified Pectoralis Major Tendon Transfer for Reanimation of Elbow Flexion as a Salvage Procedure in Complete Brachial Plexus Injury: A Case Report

Directory of Open Access Journals (Sweden)

S Taran

2013-03-01

Full Text Available Traumatic brachial plexus injuries rarely recover spontaneously and if the window period for neurotisation has elapsed, the only option for restoration of function lies in a salvage procedure. Many such salvage procedures have been described in the literature with variable functional results. We report the case of a 16-year-old boy who presented after unsuccessful treatment for a complete brachial plexus injury; we performed a pectoralis major tendon transfer to attain elbow flexion. Postoperatively, the elbow was splinted with flexion at 100°. After 4 weeks of immobilization the splint was removed and the patient could actively flex his elbow from 30° to 100°.

Mathematical geophysics an introduction to rotating fluids and the Navier-Stokes equations

CERN Document Server

Chemin, Jean-Yves; Gallagher, Isabelle; Grenier, Emmanuel

2006-01-01

Aimed at graduate students and researchers in mathematics, engineering, oceanography, meteorology and mechanics, this text provides a detailed introduction to the physical theory of rotating fluids, a significant part of geophysical fluid dynamics. The Navier-Stokes equations are examined in both incompressible and rapidly rotating forms.

Gender-Specific Effects of Artificially Induced Gender Beliefs in Mental Rotation

Science.gov (United States)

Heil, Martin; Jansen, Petra; Quaiser-Pohl, Claudia; Neuburger, Sarah

2012-01-01

Men outperform women in the Mental Rotation Test (MRT) by about one standard deviation. The present study replicated a gender belief account [Moe, A., & Pazzaglia, F. (2006). Following the instructions! Effects of gender beliefs in mental rotation. Learning and Individual Differences, 16, 369-377.] for (part of) this effect. A sample of 300…

Validity of the top-down approach of inverse dynamics analysis in fast and large rotational trunk movements.

Science.gov (United States)

Iino, Yoichi; Kojima, Takeji

2012-08-01

This study investigated the validity of the top-down approach of inverse dynamics analysis in fast and large rotational movements of the trunk about three orthogonal axes of the pelvis for nine male collegiate students. The maximum angles of the upper trunk relative to the pelvis were approximately 47°, 49°, 32°, and 55° for lateral bending, flexion, extension, and axial rotation, respectively, with maximum angular velocities of 209°/s, 201°/s, 145°/s, and 288°/s, respectively. The pelvic moments about the axes during the movements were determined using the top-down and bottom-up approaches of inverse dynamics and compared between the two approaches. Three body segment inertial parameter sets were estimated using anthropometric data sets (Ae et al., Biomechanism 11, 1992; De Leva, J Biomech, 1996; Dumas et al., J Biomech, 2007). The root-mean-square errors of the moments and the absolute errors of the peaks of the moments were generally smaller than 10 N·m. The results suggest that the pelvic moment in motions involving fast and large trunk movements can be determined with a certain level of validity using the top-down approach in which the trunk is modeled as two or three rigid-link segments.

Static and dynamic analysis of patellofemoral joint arthritis using computed tomography

International Nuclear Information System (INIS)

Nagamine, Ryuji; Inoue, Yoshihiro; Nishizawa, Masao; Hirano, Kaoru; Kawasaki, Toshiyuki

1996-01-01

Twelve parameters of the knee were evaluated using computed tomography to analyze possible etiological mechanisms leading to patello-femoral arthritis (PF-OA). Sixteen normal knees and 14 knees with PF-OA were tested. CT scans were taken at the level of the femoral epicondyles, the tibial tubercle and the malleoli of the ankle joint at full extension and 30deg of flexion. The slices were superimposed and three parameters; tibial tubercle rotation angle (TT angle), malleolar line rotation angle (ML angle) and tibial tubercle and lateral condyle angle (TT-LC angle) were measured with the central point of the medial and lateral epicondyle line as the fiducial point. Differences in each parameter between full extension and 30deg of flexion were also evaluated as dynamic factors. Three other parameters, lateral condyle rotation angle (LC angle). Lateral and medial condyle angle (LC-MC angle) and lateral condyle and patellar groove angle (LC-S) were also measured to evaluate the anatomical configuration. The position of the tibial tubercle at full extension relative to the femoral condyle was almost the same in both groups. The results, however, demonstrated that, in the PF-OA knee, the tibial tubercle stayed more lateral compared with the normal knee at 30deg of flexion. It is obvious that the tibial tubercle exists laterally in knee flexion and the patella impinges against the lateral femoral condyle in knee flexion which will cause PF-OA. (author)

Static and dynamic analysis of patellofemoral joint arthritis using computed tomography

Energy Technology Data Exchange (ETDEWEB)

Nagamine, Ryuji; Inoue, Yoshihiro; Nishizawa, Masao; Hirano, Kaoru; Kawasaki, Toshiyuki [JR Kyushu Hospital, Kitakyushu, Fukuoka (Japan)

1996-09-01

Twelve parameters of the knee were evaluated using computed tomography to analyze possible etiological mechanisms leading to patello-femoral arthritis (PF-OA). Sixteen normal knees and 14 knees with PF-OA were tested. CT scans were taken at the level of the femoral epicondyles, the tibial tubercle and the malleoli of the ankle joint at full extension and 30deg of flexion. The slices were superimposed and three parameters; tibial tubercle rotation angle (TT angle), malleolar line rotation angle (ML angle) and tibial tubercle and lateral condyle angle (TT-LC angle) were measured with the central point of the medial and lateral epicondyle line as the fiducial point. Differences in each parameter between full extension and 30deg of flexion were also evaluated as dynamic factors. Three other parameters, lateral condyle rotation angle (LC angle). Lateral and medial condyle angle (LC-MC angle) and lateral condyle and patellar groove angle (LC-S) were also measured to evaluate the anatomical configuration. The position of the tibial tubercle at full extension relative to the femoral condyle was almost the same in both groups. The results, however, demonstrated that, in the PF-OA knee, the tibial tubercle stayed more lateral compared with the normal knee at 30deg of flexion. It is obvious that the tibial tubercle exists laterally in knee flexion and the patella impinges against the lateral femoral condyle in knee flexion which will cause PF-OA. (author)

Advances in Molecular Rotational Spectroscopy for Applied Science

Science.gov (United States)

Harris, Brent; Fields, Shelby S.; Pulliam, Robin; Muckle, Matt; Neill, Justin L.

2017-06-01

Advances in chemical sensitivity and robust, solid-state designs for microwave/millimeter-wave instrumentation compel the expansion of molecular rotational spectroscopy as research tool into applied science. It is familiar to consider molecular rotational spectroscopy for air analysis. Those techniques for molecular rotational spectroscopy are included in our presentation of a more broad application space for materials analysis using Fourier Transform Molecular Rotational Resonance (FT-MRR) spectrometers. There are potentially transformative advantages for direct gas analysis of complex mixtures, determination of unknown evolved gases with parts per trillion detection limits in solid materials, and unambiguous chiral determination. The introduction of FT-MRR as an alternative detection principle for analytical chemistry has created a ripe research space for the development of new analytical methods and sampling equipment to fully enable FT-MRR. We present the current state of purpose-built FT-MRR instrumentation and the latest application measurements that make use of new sampling methods.

Paleomagnetic evidence for an inverse rotation history of Western Anatolia during the exhumation of Menderes core complex

Science.gov (United States)

Uzel, Bora; Langereis, Cornelis G.; Kaymakci, Nuretdin; Sözbilir, Hasan; Özkaymak, Çağlar; Özkaptan, Murat

2015-03-01

Within the Aegean extensional system, the İzmir-Balıkesir Transfer Zone (İBTZ) is a crucial element in the late Cenozoic evolution of western Anatolia since it accommodates the differential deformation between the Cycladic and the Menderes metamorphic core complexes. Here, we determine the rotational history of western Anatolia using new paleomagnetic data from 87 sites in Miocene volcano-sedimentary rocks to better understand the role of the İBTZ. Our results reveal two discrete and opposite major rotational phases during the Miocene. The first phase is derived from early Miocene volcanic, sedimentary and granitic rocks and is controlled by detachment and strike-slip faults. It is characterized by an average (net) 23 ± 6 ° clockwise (CW) rotation within the İBTZ since the early Miocene. Our new data from the Menderes part on the other hand show an average - 23 ± 10 ° counter-clockwise (CCW) rotation. The data from the Cycladic part show no significant (net) rotation since the early Miocene. The second phase is derived from middle-late Miocene volcanic and sedimentary rocks and is controlled by high-angle normal and strike-slip faults. The rotations from this phase show a very consistent pattern of - 22 ± 11 ° CCW within the İBTZ, while now the Menderes part shows an average CW rotation of 25 ± 14 °. Our paleomagnetic results hence document a major change and inversion of rotation. Between the early and late Miocene the İBTZ region experienced a large 45° CW rotation, while during the same time interval the Menderes part outside the zone experienced a similar (48°) CCW rotation. After that, the İBTZ became narrower and the sense of rotation inverted to CCW (- 23 ± 10 ° since the late Miocene), while in the Menderes part it inverted to CW (25 ± 14 ° since the late Miocene). Our new results do therefore fit the hypotheses of two-stage-extension scenario, rather than a one-single-phase of extension. We also conclude that the observed rotations

Secular instability of axisymmetric rotating stars to gravitational radiation reaction

International Nuclear Information System (INIS)

Managan, R.A.

1985-01-01

A generalization of the Eulerian variational principle derived by Ipser and Managan, for nonaxisymmetric neutral modes of axisymmetric fluid configurations, is developed. The principle provides a variational basis for calculating the frequencies of nonaxisymmetric normal modes proportional to e/sup i/(sigmat + mphi). A modified form of this principle, valid for sigma near 0, is also developed. The latter principle is used to locate the points where the frequency of a nonaxisymmetric normal mode of an axisymmetric rotating fluid configuration passes through zero. lt is at these points that the configuration becomes secularly unstable to gravitational radiation reaction (GRR). This is demonstrated directly by including the GRR potential and showing that the imaginary part of sigma passes through zero and becomes negative at these points. The imaginary part of the frequency is used to estimate the e-folding time of the mode. This variational principle is applied to sequences of rotating polytropes. The sequences are constructed using four rotation laws at each value of the polytropic index n = 0.5, 1.0, 1.5, 2.0, and 3.0. The values of (T/W)/sub m/, the ratio of the rotational kinetic energy to the magnitude of the gravitational potential energy at the onset of instability, and timescales for the modes with m = 2, 3, and 4 are estimated for each sequence. The value of (T/W) 2 is largely independent of the equation of state and rotation law. For m > 2, (T/W)/sub m/ decreases as the equation of state becomes softer, i.e., as the polytropic index n increases, and increases as the amount of differential rotation increases. The most striking result of this behavior occurs for uniform rotation

Comparative study of phrenic nerve transfers with and without nerve graft for elbow flexion after global brachial plexus injury.

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Liu, Yuzhou; Lao, Jie; Gao, Kaiming; Gu, Yudong; Zhao, Xin

2014-01-01

Nerve transfer is a valuable surgical technique in peripheral nerve reconstruction, especially in brachial plexus injuries. Phrenic nerve transfer for elbow flexion was proved to be one of the optimal procedures in the treatment of brachial plexus injuries in the study of Gu et al. The aim of this study was to compare phrenic nerve transfers with and without nerve graft for elbow flexion after brachial plexus injury. A retrospective review of 33 patients treated with phrenic nerve transfer for elbow flexion in posttraumatic global root avulsion brachial plexus injury was carried out. All the 33 patients were confirmed to have global root avulsion brachial plexus injury by preoperative and intraoperative electromyography (EMG), physical examination and especially by intraoperative exploration. There were two types of phrenic nerve transfers: type1 - the phrenic nerve to anterolateral bundle of anterior division of upper trunk (14 patients); type 2 - the phrenic nerve via nerve graft to anterolateral bundle of musculocutaneous nerve (19 patients). Motor function and EMG evaluation were performed at least 3 years after surgery. The efficiency of motor function in type 1 was 86%, while it was 84% in type 2. The two groups were not statistically different in terms of Medical Research Council (MRC) grade (p=1.000) and EMG results (p=1.000). There were seven patients with more than 4 month's delay of surgery, among whom only three patients regained biceps power to M3 strength or above (43%). A total of 26 patients had reconstruction done within 4 months, among whom 25 patients recovered to M3 strength or above (96%). There was a statistically significant difference of motor function between the delay of surgery within 4 months and more than 4 months (p=0.008). Phrenic nerve transfers with and without nerve graft for elbow flexion after brachial plexus injury had no significant difference for biceps reinnervation according to MRC grading and EMG. A delay of the surgery

Running in ostriches (Struthio camelus): three-dimensional joint axes alignment and joint kinematics.

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Rubenson, Jonas; Lloyd, David G; Besier, Thor F; Heliams, Denham B; Fournier, Paul A

2007-07-01

Although locomotor kinematics in walking and running birds have been examined in studies exploring many biological aspects of bipedalism, these studies have been largely limited to two-dimensional analyses. Incorporating a five-segment, 17 degree-of-freedom (d.f.) kinematic model of the ostrich hind limb developed from anatomical specimens, we quantified the three-dimensional (3-D) joint axis alignment and joint kinematics during running (at approximately 3.3 m s(-1)) in the largest avian biped, the ostrich. Our analysis revealed that the majority of the segment motion during running in the ostrich occurs in flexion/extension. Importantly, however, the alignment of the average flexion/extension helical axes of the knee and ankle are rotated externally to the direction of travel (37 degrees and 21 degrees , respectively) so that pure flexion and extension at the knee will act to adduct and adbuct the tibiotarsus relative to the plane of movement, and pure flexion and extension at the ankle will act to abduct and adduct the tarsometatarsus relative to the plane of movement. This feature of the limb anatomy appears to provide the major lateral (non-sagittal) displacement of the lower limb necessary for steering the swinging limb clear of the stance limb and replaces what would otherwise require greater adduction/abduction and/or internal/external rotation, allowing for less complex joints, musculoskeletal geometry and neuromuscular control. Significant rotation about the joints' non-flexion/extension axes nevertheless occurs over the running stride. In particular, hip abduction and knee internal/external and varus/valgus motion may further facilitate limb clearance during the swing phase, and substantial non-flexion/extension movement at the knee is also observed during stance. Measurement of 3-D segment and joint motion in birds will be aided by the use of functionally determined axes of rotation rather than assumed axes, proving important when interpreting the

Post-operative Hypertension following Correction of Flexion Deformity of the Knees in a Spastic Diplegic Child: A Case Report

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Vipin Mohan

2016-11-01

Full Text Available An adolescent boy with spastic diplegic cerebral palsy presented with crouch gait. He had bilateral severe flexion deformities of knees and hips. He was treated with single event multilevel surgery for the correction of deformities. Surgical procedures included bilateral adductor release, iliopsoas lengthening, bilateral femoral shortening and patella plication. Persistent hypertension was noted in the post-operative period. All causes of secondary hypertension were ruled out. Having persistent hypertension following the femoral shortening procedure is unusual. Antihypertensive medication controlled his blood pressure 15 months after surgery. Hypertension following correction of knee flexion deformity and limb lengthening is well known. Hypertension has not been described with the shortening osteotomy of the femur. Hypertension is a rare complication following the corrective surgery for the treatment of crouch gait. Blood pressure should be monitored during the post-operative period to detect such a rare complication.

Configurable 3D rotational X-ray reconstruction

NARCIS (Netherlands)

Nguyen, Xuan Huy

2012-01-01

This report is one of the deliverables of the project "Configurable 3D Rotational X-ray Reconstruction", carried out by the author as the final part of the Professional Doctorate in Engineering (PDEng) degree program in Software Technology provided by Eindhoven University of Technology and Stan

Power frequency spectrum analysis of surface EMG signals of upper limb muscles during elbow flexion - A comparison between healthy subjects and stroke survivors.

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Angelova, Silvija; Ribagin, Simeon; Raikova, Rositsa; Veneva, Ivanka

2018-02-01

After a stroke, motor units stop working properly and large, fast-twitch units are more frequently affected. Their impaired functions can be investigated during dynamic tasks using electromyographic (EMG) signal analysis. The aim of this paper is to investigate changes in the parameters of the power/frequency function during elbow flexion between affected, non-affected, and healthy muscles. Fifteen healthy subjects and ten stroke survivors participated in the experiments. Electromyographic data from 6 muscles of the upper limbs during elbow flexion were filtered and normalized to the amplitudes of EMG signals during maximal isometric tasks. The moments when motion started and when the flexion angle reached its maximal value were found. Equal intervals of 0.3407 s were defined between these two moments and one additional interval before the start of the flexion (first one) was supplemented. For each of these intervals the power/frequency function of EMG signals was calculated. The mean (MNF) and median frequencies (MDF), the maximal power (MPw) and the area under the power function (APw) were calculated. MNF was always higher than MDF. A significant decrease in these frequencies was found in only three post-stroke survivors. The frequencies in the first time interval were nearly always the highest among all intervals. The maximal power was nearly zero during first time interval and increased during the next ones. The largest values of MPw and APw were found for the flexor muscles and they increased for the muscles of the affected arm compared to the non-affected one of stroke survivors. Copyright © 2017 Elsevier Ltd. All rights reserved.

CT imaging techniques for describing motions of the cervicothoracic junction and cervical spine during flexion, extension, and cervical traction.

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Simon, Scott; Davis, Martin; Odhner, Dewey; Udupa, Jayaram; Winkelstein, Beth

2006-01-01

Computerized tomographic study of human cadavers undergoing traction and flexion-extension bending. To investigate the feasibility of using computerized tomography techniques to quantify relative vertebral motions of the cervical spine and cervicothoracic junction (CTJ), and to define normative CTJ kinematics. Despite developing an understanding of the mechanical behavior of the cervical spine, little remains known about the cervicothoracic junction. The CTJ is more difficult to image than other cervical regions given the anatomic features of the surrounding bones obstructing CTJ visualization. As such, limited data have been reported describing the responses of the CTJ for motions and loading in the sagittal plane, confounding the clinical assessment of its injuries and surgical treatments used at this region. Helical CT images of the cervical spine and CTJ were acquired incrementally during each of flexion, extension, and cervical traction. Vertebral surfaces were reconstructed using the specialized image analysis software, 3DVIEWNIX. A mathematical description of relative vertebral motions was derived by computing rigid transformations. Euler angles and translations were calculated. Regional spine stiffness was defined for traction. The CTJ was found to be much stiffer (779 N/mm) than the cervical spine (317 N/mm) in tension. In flexion-extension bending, the CTJ was similar to the lower cervical spine. The CTJ demonstrated significantly less coupled motion than the cervical spine. The CTJ, as a transition region between the cervical and thoracic spines, has unique kinematic characteristics. This application of kinematic CT methods is useful for quantifying unreported normative ranges of motion for the CTJ, difficult by other conventional radiologic means.

Rotations et moments angulaires enmécanique quantique

Science.gov (United States)

van de Wiele, J.

Rotations and angular moments in quantum mechanics As in classical mechanics, rotation in quantum mechanics is a transformation which deals with angular momentum. The difference with classical mechanics comes from the fact that angular momentum is a vector operator and not a usual vector and its components do not commute. As for any transformation in quantum mechanics, to each rotation we can associate an operator which acts in state space. The expression of this operator depends on whether the rotation is passive, that is we do a rotation of the coordinate axes and the physical system is left unchanged, or active, in which case the coordinate axes are unchanged and the rotation is performed on the physical system. In the first part (Chaps. 1 and 2) of this book, details concerning both aspects are given. Following the definition of the geometrical transformation associated with the most general rotation, we give the expression of the rotation operator for specific cases. Transformation laws for scalar fields, vector fields and spinor fields are given as well as transformation laws for scalar operators, vector operators and more generally, for operators of any rank. The second part (Chaps. 3 and 4) deals with angular momentum algebra. We define the coupling coefficients of 2, 3 and 4 angular momenta as well as the recoupling coefficients. The definition of the irreductible tensor operator, which is a generalisation of scalar and vector operators, is given as well as the Wigner-Eckart theorem. The application of this theorem to more complex cases is studied. Comme en mécanique classique, la rotation en mécanique quantique est une transformation qui fait intervenir le moment cinétique. La différence avec la mécanique classique vient du fait que le moment cinétique est un opérateur vectoriel et non pas un vecteur ordinaire, et que ses composantes ne commutent pas deux-à-deux. Comme pour toute transformation en mécanique quantique, à chaque rotation est

"Popeye muscle" morphology in OBPI elbow flexion contracture.

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Coroneos, Christopher J; Maizlin, Zeev V; DeMatteo, Carol; Gjertsen, Deborah; Bain, James R

2015-01-01

The pathophysiology of elbow flexion contracture (EFC) in obstetrical brachial plexus injury (OBPI) is not established. In basic science models, neonatal denervation leads to impaired muscle growth. In clinical studies, diminished growth is correlated with extent of denervation, and improved with surgical repair. In EFC, the biceps are clinically short and round vs the contralateral size, termed the "Popeye muscle". The objective of this study was to determine if the biceps morphology (muscle belly and tendon length) in arms with EFC secondary to OBPI is different vs the contralateral. This is a retrospective matched-cohort study. Patients with unilateral EFC (>20°) secondary to OBPI were identified (median = 6.6 years, range = 4.7-16.8). A blinded radiologist used computed tomography to measure length of the biceps short head muscle belly, and tendon bilaterally using standardised anatomical landmarks. Twelve patients were analyzed. The biceps muscle belly in the injured arm was shorter in all patients vs contralateral, mean difference = 3.6 cm (80%), p muscle belly and overall length, but longer tendon vs normal. This is termed the "Popeye muscle" for its irregular morphology. Findings are consistent with impaired limb growth in denervation.

Can Physical Examination Create a Stener Lesion?

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Lankachandra, Manesha; Eggers, John P; Bogener, James W; Hutchison, Richard L

2017-09-01

The purpose of this study is to determine whether a Stener lesion can be created while testing stability of the ulnar collateral ligament (UCL) of the thumb. Testing was performed in a manner that reproduced clinical examination. Six fresh frozen hand and forearm specimens underwent sequential sectioning of the accessory UCL, the proper UCL, and the ulnar sagittal band. Measurements of radial deviation of the metacarpophalangeal (MCP) joint were taken with the thumb in neutral rotation, pronation and supination, both with 0 degrees and with 30 degrees of flexion of the MCP joint. Visual examination was performed to assess the presence of a Stener lesion. No Stener lesion was created in any position as long as the fascial origin of the ulnar sagittal band at the adductor pollicis longus remained intact. After creating a defect in the ulnar sagittal band, a Stener lesion was created in two specimens, but only when the thumb was flexed and supinated. Pronation provided more stability, and supination provided less stability, with one or both components cut, especially when testing at 30° of flexion. Compared to both components cut without flexion or rotation, there was a statistically significant difference in angulation with the 30 degrees of MCP joint flexion in both neutral rotation in supination. Performing a physical examination to assess the amount of instability of an ulnar collateral ligament injury did not create a Stener lesion if the exam was performed in a controlled, gentle manner with the thumb held without rotation. If the thumb is held in neutral rotation during the exam, an iatrogenic Stener lesion should not be created.

The pattern and technique in the clinical evaluation of the adult hip: the common physical examination tests of hip specialists.

Science.gov (United States)

Martin, Hal D; Kelly, Bryan T; Leunig, Michael; Philippon, Marc J; Clohisy, John C; Martin, RobRoy L; Sekiya, Jon K; Pietrobon, Ricardo; Mohtadi, Nicholas G; Sampson, Thomas G; Safran, Marc R

2010-02-01

The purpose of this study was to systematically evaluate the technique and tests used in the physical examination of the adult hip performed by multiple clinicians who regularly treat patients with hip problems and identify common physical examination patterns. The subjects included 5 men and 6 women with a mean age (+/-SD) of 29.8 +/- 9.4 years. They underwent physical examination of the hip by 6 hip specialists with a strong interest in hip-related problems. All examiners were blind to patient radiographs and diagnoses. Patient examinations were video recorded and reviewed. It was determined that 18 tests were most frequently performed (>or=40%) by the examiners, 3 standing, 11 supine, 3 lateral, and 1 prone. Of the most frequently performed tests, 10 were performed more than 50% of the time. The tests performed in the supine position were as follows: flexion range of motion (ROM) (percentage of use, 98%), flexion internal rotation ROM (98%), flexion external rotation ROM (86%), passive supine rotation test (76%), flexion/adduction/internal rotation test (70%), straight leg raise against resistance test (61%), and flexion/abduction/external rotation test (52%). The tests performed in the standing position were the gait test (86%) and the single-leg stance phase test (77%). The 1 test in the prone position was the femoral anteversion test (58%). There are variations in the testing that hip specialists perform to examine and evaluate their patients, but there is enough commonality to form the basis to recommend a battery of physical examination maneuvers that should be considered for use in evaluating the hip. Patients presenting with groin, abdominal, back, and/or hip pain need to have a basic examination to ensure that the hip is not overlooked. A comprehensive physical examination of the hip will benefit the patient and the physician and serve as the foundation for future multicenter clinical studies. (c) 2010 Arthroscopy Association of North America. Published

Using verbal instructions to influence lifting mechanics - Does the directive "lift with your legs, not your back" attenuate spinal flexion?

Science.gov (United States)

Beach, Tyson A C; Stankovic, Tatjana; Carnegie, Danielle R; Micay, Rachel; Frost, David M

2018-02-01

"Use your legs" is commonly perceived as sound advice to prevent lifting-related low-back pain and injuries, but there is limited evidence that this directive attenuates the concomitant biomechanical risk factors. Body segment kinematic data were collected from 12 men and 12 women who performed a laboratory lifting/lowering task after being provided with different verbal instructions. The main finding was that instructing participants to lift "without rounding your lower back" had a greater effect on the amount of spine flexion they exhibited when lifting/lowering than instructing them to lift "with your legs instead of your back" and "bend your knees and hips". It was concluded that if using verbal instructions to discourage spine flexion when lifting, the instructions should be spine- rather than leg-focused. Copyright © 2017 Elsevier Ltd. All rights reserved.

ROTATION AND MAGNETIC ACTIVITY IN A SAMPLE OF M-DWARFS

International Nuclear Information System (INIS)

Browning, Matthew K.; Basri, Gibor; Marcy, Geoffrey W.; Zhang Jiahao; West, Andrew A.

2010-01-01

We have analyzed the rotational broadening and chromospheric activity in a sample of 123 M-dwarfs, using spectra taken at the W.M. Keck Observatory as part of the California Planet Search program. We find that only seven of these stars are rotating more rapidly than our detection threshold of v sin i ∼ 2.5 km s -1 . Rotation appears to be more common in stars later than M3 than in the M0-M2.5 mass range: we estimate that less than 10% of early-M stars are detectably rotating, whereas roughly a third of those later than M4 show signs of rotation. These findings lend support to the view that rotational braking becomes less effective in fully convective stars. By measuring the equivalent widths of the Ca II H and K lines for the stars in our sample, and converting these to approximate L Ca /L bol measurements, we also provide constraints on the connection between rotation and magnetic activity. Measurable rotation is a sufficient, but not necessary condition for activity in our sample: all the detectable rotators show strong Ca II emission, but so too do a small number of non-rotating stars, which we presume may lie at high inclination angles relative to our line of sight. Our data are consistent with a 'saturation-type' rotation-activity relationship, with activity roughly independent of rotation above a threshold velocity of less than 6 km s -1 . We also find weak evidence for a 'gap' in L Ca /L bol between a highly active population of stars, which typically are detected as rotators, and another much less active group.

The effect of resistance level and stability demands on recruitment patterns and internal loading of spine in dynamic flexion and extension using a simple trunk model.

Science.gov (United States)

Zeinali-Davarani, Shahrokh; Shirazi-Adl, Aboulfazl; Dariush, Behzad; Hemami, Hooshang; Parnianpour, Mohamad

2011-07-01

The effects of external resistance on the recruitment of trunk muscles in sagittal movements and the coactivation mechanism to maintain spinal stability were investigated using a simple computational model of iso-resistive spine sagittal movements. Neural excitation of muscles was attained based on inverse dynamics approach along with a stability-based optimisation. The trunk flexion and extension movements between 60° flexion and the upright posture against various resistance levels were simulated. Incorporation of the stability constraint in the optimisation algorithm required higher antagonistic activities for all resistance levels mostly close to the upright position. Extension movements showed higher coactivation with higher resistance, whereas flexion movements demonstrated lower coactivation indicating a greater stability demand in backward extension movements against higher resistance at the neighbourhood of the upright posture. Optimal extension profiles based on minimum jerk, work and power had distinct kinematics profiles which led to recruitment patterns with different timing and amplitude of activation.

Effect of Ankle Positioning During Hamstring Stretches for Improving Straight Leg Hip Flexion Motion.

Science.gov (United States)

Laudner, Kevin G; Benjamin, Peter J; Selkow, Noelle M

2016-03-01

To compare the effects of stretching the hamstrings with the ankle in either a plantar-flexed (PF) or dorsiflexed (DF) position for improving straight leg hip flexion range of motion (ROM) over a 4-week period. Randomized, single-blinded, pretest, posttest design. Athletic training facility. Each limb of 34 asymptomatic individuals (15 males, 19 females) was randomly assigned to one of the 3 groups. Twenty-four limbs received hamstring stretches with the ankle in DF, 24 limbs received hamstring stretches with the ankle in PF, and 20 limbs received no stretch (control). Ankle position (PF, DF) during hamstring stretching. We measured pretest and posttest passive straight leg hip flexion ROM with the test ankle in a neutral position. For the intervention groups, the test limb was passively stretched with the ankle held in end range DF or PF for their respective group. Each stretch was held for 30 seconds for a total of 3 applications. Two treatment sessions were completed per week for a total of 4 weeks. The control limbs received no stretching during the 4-week period. We conducted 1-way analyses of covariance to determine significant changes in ROM between groups (P hamstrings in either PF or DF improve straight leg hip ROM compared with a control group. The results of this study should be considered by clinicians when determining the optimal stretching techniques aimed at increasing hamstring length.

Knee flexion contracture treated with botulinum toxin type A in patients with haemophilia (PWH).

Science.gov (United States)

Daffunchio, C; Caviglia, H; Nassif, J; Morettil, N; Galatro, G

2016-01-01

Knee flexion contracture (KFC) remains a common complication of haemoarthrosis in children and young adults with haemophilia. If the KFC is not treated properly it produces disability, postural and gait abnormalities. Evaluate the effectiveness of conservative treatment of KFC with Botulinum toxin type A (BTX-A) in PWH. Seventeen patients were treated, with 21 affected knees. Mean age was 26 years. The mean follow up was 12 months. We evaluated flexion and KFC pretreatment BTX-A and up to 12 months posttreatment. BTX-A application was in hamstring and calf muscles. To evaluate the function, a questionnaire about different activities was made, and it was checked 3, 6 and 12 months after BTX-A. According to the degree of KFC, knees were divided into 3 groups: Group 1: -10° to -30° (n = 10), Group 2: -31° to -45° (n = 6) Group 3: -46° or more (n = 5). The average KFC improved from -38° to -24°. The improvement was 14° (P KFC improvement was 9° in group 1, 17° in group 2, and 23° in group 3. There was a high correlation between the improvement in KFC and the total score of the questionnaire R = 0.77. Treatment of KFC with BTX-A improves knee-related functional activities, with the advantage of being a low-cost procedure and easy to apply. © 2015 John Wiley & Sons Ltd.

Axisymmetric flow in a cylindrical tank over a rotating bottom. Part II. Deformation of the water surface and experimental verification of the theory

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Iga, Keita; Watanabe, Shunichi; Niino, Hiroshi; Misawa, Nobuhiko [Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8564 (Japan); Yokota, Sho [Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052 (Japan); Ikeda, Takashi, E-mail: iga@aori.u-tokyo.ac.jp [Japan Patent Office, 3-4-3 Kasumigaseki, Chiyoda, Tokyo 100-8915 (Japan)

2017-12-15

The theory of axisymmetric flow in a cylindrical container with a rotating bottom, as described in Part I, is validated against the results of previous and our own laboratory experiments. First, deformation of the water surface is derived using the velocity distribution of the axisymmetric flow obtained by the theory. The form of the water surface is classified into three regimes, and the rotation rates of the transitions between these regimes are determined. The parameters predicted from this theory are compared with the results measured in laboratory experiments and also with data from previous experimental studies. The theory predicts the experimental data well, but a slight difference was found in the narrow region close to the side wall. Corrections estimated by considering the fluid behavior around the side wall boundary layer successfully explain most of the discrepancies. This theory appears to predict the results of the laboratory experiments very well, much better than a theory using an assumption of quadratic drag as a model of turbulent boundary layers. (paper)

Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror

Science.gov (United States)

Li, Steven

2011-01-01

A laser cavity was designed and implemented by using a wedged polarization rotator and a Porro prism in order to reduce the parts count, and to improve the laser reliability. In this invention, a z-cut quartz polarization rotator is used to compensate the wavelength retardance introduced by the Porro prism. The polarization rotator rotates the polarization of the linear polarized beam with a designed angle that is independent of the orientation of the rotator. This unique property was used to combine the retardance compensation and a Risley prism to a single optical component: a wedged polarization rotator. This greatly simplifies the laser alignment procedure and reduces the number of the laser optical components.

Radial-rotation profile forming: A new processing technology of incremental sheet metal forming

Science.gov (United States)

Laue, Robert; Härtel, Sebastian; Awiszus, Birgit

2018-05-01

Incremental forming processes (i.e., spinning) of sheet metal blanks into cylindrical cups are suitable for lower lot sizes. The produced cups were frequently used as preforms to produce workpieces in further forming steps with additional functions like profiled hollow parts [1]. The incremental forming process radial-rotation profile forming has been developed to enable the production of profiled hollow parts with low sheet thinning and good geometrical accuracy. The two principal forming steps are the production of the preform by rotational swing-folding [2] and the subsequent radial profiling of the hollow part in one clamping position. The rotational swing-folding process is based on a combination of conventional spinning and swing-folding. Therefore, a round blank rotates on a profiled mandrel and due to the swinging of a cylindrical forming tool, the blank is formed to a cup with low sheet thinning. In addition, thickening results at the edge of the blank and wrinkling occurs. However, the wrinkles are formed into the indentation of the profiled mandrel and can be reshaped as an advantage in the second process step, the radial profiling. Due to the rotation and continuous radial feed of a profiled forming tool to the profiled mandrel, the axial profile is formed in the second process step. Because of the minor relative movement in axial direction between tool and blank, low sheet thinning occurs. This is an advantage of the principle of the process.

The new INRIM rotating encoder angle comparator (REAC)

International Nuclear Information System (INIS)

Pisani, Marco; Astrua, Milena

2017-01-01

A novel angle comparator has been built and tested at INRIM. The device is based on a double air bearing structure embedding a continuously rotating encoder, which is read by two heads: one fixed to the base of the comparator and a second fixed to the upper moving part of the comparator. The phase measurement between the two heads’ signals is proportional to the relative angle suspended between them (and, therefore, the angle between the base and the upper, movable part of the comparator). The advantage of this solution is to reduce the encoder graduation errors and to cancel the cyclic errors due to the interpolation of the encoder lines. By using only two pairs of reading heads, we have achieved an intrinsic accuracy of  ±0.04″ (rectangular distribution) that can be reduced through self-calibration. The residual cyclic errors have shown to be less than 0.01″ peak-to-peak. The random fluctuations are less than 0.01″ rms on a 100 s time interval. A further advantage of the rotating encoder is the intrinsic knowledge of the absolute position without the need of a zeroing procedure. Construction details of the rotating encoder angle comparator (REAC), characterization tests, and examples of practical use are given. (paper)

Effect of a physical training program using the Pilates method on flexibility in elderly subjects.

Science.gov (United States)

Geremia, Jeam Marcel; Iskiewicz, Matheus Magalhães; Marschner, Rafael Aguiar; Lehnen, Tatiana Ederich; Lehnen, Alexandre Machado

2015-12-01

The adaptations of the human body resulting from the aging process especially loss of flexibility can increase the risk of falls and the risk of developing other health conditions. Exercise training, in particular the Pilates exercise method, has become an important form of physical activity that minimizes the deleterious effects of aging on flexibility. Few studies have evaluated the effect of this training method on body flexibility among elderly. We aimed to evaluate the effects of physical training using the Pilates method on body flexibility of elderly individuals. Eighteen elderly women and two elderly men (aged 70 ± 4 years) followed a 10-week Pilates training program. Individuals were recruited from the local community via open invitations. At study entry, none of them had limited mobility (walking requiring the use of walkers or canes). Furthermore, those with neurologic, muscular, or psychiatric disorders as well as those using an assistive device for ambulation were excluded secondary to limited participation. Flexibility assessment tests (flexion, extension, right and left tilt, and right and left rotation of the cervical and thoracolumbar spine; flexion, extension, abduction, and lateral and medial right and left rotation of the glenohumeral joint; flexion, extension, abduction, adduction, and lateral and medial rotation of the right and left hip; and flexion of the right and left knee) were performed by a blinded evaluator using a flexometer before and after the training period. All assessments were carried out at the same time of day. There was an observed increase in flexion (22.86%; p falls).

Influence of Head and Neck Position on Oropharyngeal Leak Pressure and Cuff Position with the ProSeal Laryngeal Mask Airway and the I-Gel: A Randomized Clinical Trial

Directory of Open Access Journals (Sweden)

Sandeep Kumar Mishra

2015-01-01

Full Text Available Background. This study was designed to assess and compare the effect of head and neck position on the oropharyngeal leak pressures and cuff position (employing fibreoptic view of the glottis and ventilation scores between ProSeal LMA and the I-gel. Material and Methods. After induction of anesthesia, the supraglottic device was inserted and ventilation confirmed. The position of the head was randomly changed from neutral to flexion, extension, and lateral rotation (left. The oropharyngeal leak pressures, fibreoptic view of glottis, ventilation scores, and delivered tidal volumes and end tidal CO2 were noted in all positions. Results. In both groups compared with neutral position, oropharyngeal leak pressures were significantly higher with flexion and lower with extension but similar with rotation of head and neck. However the oropharyngeal leak pressure was significantly higher for ProSeal LMA compared with the I-gel in all positions. Peak airway pressures were significantly higher with flexion in both groups (however this did not affect ventilation, lower with extension in ProSeal group, and comparable in I-gel group but did not change significantly with rotation of head and neck in both groups. Conclusion. Effective ventilation can be done with both ProSeal LMA and I-gel with head in all the above positions. ProSeal LMA has a better margin of safety than I-gel due to better sealing pressures except in flexion where the increase in airway pressure is more with the former. Extreme precaution should be taken in flexion position in ProSeal LMA.

Intraoperative joint gaps and mediolateral balance affect postoperative knee kinematics in posterior-stabilized total knee arthroplasty.

Science.gov (United States)

Watanabe, Toshifumi; Muneta, Takeshi; Sekiya, Ichiro; Banks, Scott A

2015-12-01

Adjusting joint gaps and establishing mediolateral (ML) soft tissue balance are considered essential interventions for better outcomes in total knee arthroplasty (TKA). However, the relationship between intraoperative laxity measurements and weightbearing knee kinematics has not been well explored. This study aimed to quantify the effect of intraoperative joint gaps and ML soft tissue balance on postoperative knee kinematics in posterior-stabilized (PS)-TKA. We investigated 44 knees in 34 patients who underwent primary PS-TKA by a single surgeon. The central joint gaps and ML tilting angles at 0°, 10°, 30°, 60°, 90°, 120° and 135° flexion were measured during surgery. At a minimum of two year follow-up, we analyzed in vivo kinematics of these knees and examined the influence of intraoperative measurements on postoperative kinematics. Gap difference of knee flexion at 135° minus 0° was correlated with the total posterior translation of lateral femoral condyle (r=0.336, p=0.042) and femoral external rotation (r=0.488, p=0.002) during squatting, anteroposterior position of lateral femoral condyle (r=-0.510, p=0.001) and maximum knee flexion (r=0.355, p=0.031) in kneeling. Similar correlations were observed between deep flexion gap differences with respect to the 90° reference and postoperative knee kinematics. Well-balanced knees showed less anterior translation of medial femoral condyle in mid- to deep flexion, consistent femoral external rotation, and the most neutral valgus/varus rotation compared with unbalanced knees. These findings indicate the importance of adequate intraoperative joint gaps in deep flexion and ML soft tissue balance throughout the range of motion. Copyright © 2015 Elsevier B.V. All rights reserved.

PROBING THE ROSETTE NEBULA STELLAR BUBBLE WITH FARADAY ROTATION

Energy Technology Data Exchange (ETDEWEB)

Savage, Allison H.; Spangler, Steven R.; Fischer, Patrick D. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

2013-03-01

We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m{sup -2}. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m{sup -2}, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

Broadband Rotational Spectroscopy

Science.gov (United States)

Pate, Brooks

2014-06-01

The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

The short-term effectiveness of balance taping on acute nonspecific low-back pain: A case report.

Science.gov (United States)

Lee, Jung-Hoon

2017-12-01

Low back pain has a significant socioeconomic impact. Repetitive lifting, with combined twisting and flexion motions of the lumbar spine, increases the risk for low-back pain and injury to the supporting tissues. A 60-year-old male who presented with acute low-back pain, with a pain intensity of 6/10 on the visual analog scale (VAS) and an Oswestry disability index (ODI) score of 70%. The range of motion (ROM) of the lumbar spine on initial examination, relative to the normal peak ROM, was as follows: extension, 12°/30°; flexion, 15°/80°; left rotation, 15°/45°; and right rotation, 25°/45°. He was diagnosed as acute nonspecific low-back pain sustained with repetitive lifting, combining motions of flexion and twisting. The balance taping was applied for 16 h/day, on average, for 3 consecutive days was used as the primary treatment to manage the patient's low-back pain. The application of balance taping increased the range of motion of the lumbar spine as follows: flexion, from 15° to 77°; extension, from 12° to 27°; right rotation, from 25° to 45°; and left rotation, from 15° to 45°. The ODI score decreased from 70% to 0%, and the VAS score from 6/10 to 0. We propose that balance taping using kinesiology tape could serve as a complementary approach to other treatments for the treatment of acute nonspecific low-back pain. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

1999-01-01

In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belo...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion......In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

The influence of geophysical processes on the Earth's rotation

International Nuclear Information System (INIS)

Nastula, J.

1985-01-01

The problem of the influence of geophysical processes on the Earth's rotation is presented. The role of these processes in the variations of the length of day is described in this part. 27 refs., 19 figs. (author)

Design of a rotating-hearth furnace

Energy Technology Data Exchange (ETDEWEB)

Behrens, H A [LOI Industrieofenanlagen G.m.b.H., Essen (Germany, F.R.)

1979-09-01

Part I of this paper is intended to present a review of the theory of heating round stock of a length considerably exceeding the diameter. It is permissible to neglect heating from the ends of the cylinders. With short and thick ingots as used in pilgrim mills, for instance, such simplification is not possible. The method for calculating the waste gas temperature can also be used for the remaining furnace sections provided certain conditions are allowed for and computational procedures observed. Part II of the paper will deal with this and with the major design features of rotating-hearth furnaces.

Postural Effects on the Mental Rotation of Body-Related Pictures: An fMRI Study

Directory of Open Access Journals (Sweden)

Fangbing Qu

2018-05-01

Full Text Available This study investigated the embodied effects involved in the mental rotation of pictures of body parts (hands and feet. Blood oxygen level-dependent (BOLD signals were collected from 18 healthy volunteers who performed mental rotation tasks of rotated drawings of hands under different arm postures. Congruent drawings of hands (those congruent with left-hand posture evoked stronger activation in the left supplementary motor area (SMA, left precentral gyrus, and left superior parietal lobule (SPL than did incongruent drawings of hands. Congruent drawings of hands (those congruent with right-hand posture evoked significant activation in the left inferior parietal lobule (IPL, right SMA, bilateral middle frontal gyrus (MFG, left inferior frontal gyrus (IFG, and bilateral superior frontal gyrus (SFG compared to that evoked by the incongruent drawings of hands. Similar methodology was implemented with drawings of feet. However, no significant differences in brain activation were observed between congruent and incongruent drawings of feet. This finding suggests that body posture influences body part-related mental rotation in an effector-specific manner. A direct comparison between the medially and laterally rotated drawings revealed activation in the right IPL, left precentral gyrus, bilateral IFG, and bilateral SFG. These results suggest that biomechanical constraints affect the cognitive process of mental rotation.

The choice of a constitutive formulation for modeling limb flexion-induced deformations and stresses in the human femoropopliteal arteries of different ages.

Science.gov (United States)

Desyatova, Anastasia; MacTaggart, Jason; Poulson, William; Deegan, Paul; Lomneth, Carol; Sandip, Anjali; Kamenskiy, Alexey

2017-06-01

Open and endovascular treatments for peripheral arterial disease are notorious for high failure rates. Severe mechanical deformations experienced by the femoropopliteal artery (FPA) during limb flexion and interactions between the artery and repair materials play important roles and may contribute to poor clinical outcomes. Computational modeling can help optimize FPA repair, but these simulations heavily depend on the choice of constitutive model describing the arterial behavior. In this study finite element model of the FPA in the standing (straight) and gardening (acutely bent) postures was built using computed tomography data, longitudinal pre-stretch and biaxially determined mechanical properties. Springs and dashpots were used to represent surrounding tissue forces associated with limb flexion-induced deformations. These forces were then used with age-specific longitudinal pre-stretch and mechanical properties to obtain deformed FPA configurations for seven age groups. Four commonly used invariant-based constitutive models were compared to determine the accuracy of capturing deformations and stresses in each age group. The four-fiber FPA model most accurately portrayed arterial behavior in all ages, but in subjects younger than 40 years, the performance of all constitutive formulations was similar. In older subjects, Demiray (Delfino) and classic two-fiber Holzapfel-Gasser-Ogden formulations were better than the Neo-Hookean model for predicting deformations due to limb flexion, but both significantly overestimated principal stresses compared to the FPA or Neo-Hookean models.

Physician training rotations in a large urban health department.

Science.gov (United States)

Alkon, Ellen; Kim-Farley, Robert; Gunzenhauser, Jeffrey

2014-01-01

Hospitals are the normal setting for physician residency training within the United States. When a hospital cannot provide the specific training needed, a special rotation for that experience is arranged. Linkages between clinical and public health systems are vital to achieving improvements in overall health status in the United States. Nevertheless, most physicians in postgraduate residency programs receive neither training nor practical experience in the practice of public health. For many years, public health rotations have been available within the Los Angeles County Department of Public Health (and its antecedent organizations). Arrangements that existed with local medical schools for residents to rotate with Los Angeles County Department of Health hospitals were extended to include a public health rotation. A general model for the rotation ensured that each resident received education and training relevant to the clinician in practice. Some parts of the model for experience have changed over time while others have not. Also, the challenges and opportunities for both trainees and preceptors have evolved and varied over time. A logic model demonstrates the components and changes with the public health rotation. Changes included alterations in recruitment, expectations, evaluation, formal education, and concepts related to the experience. Changes in the rotation model occurred in the context of other major environmental changes such as new electronic technology, changing expectations for residents, and evolving health services and public health systems. Each impacted the public health rotation. The evaluation method developed included content tests, assessment of competencies by residents and preceptors, and satisfaction measures. Results from the evaluation showed increases in competency and a high level of satisfaction after a public health rotation. The article includes examples of challenges and benefits to a local health department in providing a public

Rotational and translational diffusions of fluorescent probes during gelation process

Science.gov (United States)

Hattori, Yusuke; Panizza, Pascal; Letamendia, Louis; Ushiki, Hideharu

2006-04-01

Gelation process has been investigated by using light scattering techniques in recent years. We measured both of rotational and translational motions of fluorescent probes during gelation process. The measurements were performed after the temperature quenched at 30 °C. As the results, rotational diffusion coefficient of fluorescein was decreased after 6.0 × 10 4 s and energy transfer rate was reduced after 2.0 × 10 4 s. We sorted the gelation process into the following three parts, (I) pre-gelation, (II) reduction of translational diffusion (aging), and (III) reduction of rotational diffusion with saturating translational diffusion (post-gelation). The time scale of the process was completely different from the results of other methods.

Physical activity as a remedy for "cheerful" aging which prevents from chronic diseases

Directory of Open Access Journals (Sweden)

Alicja Rzepka

2016-12-01

Full Text Available Purpose. According to GUS, only 3.6% of the elderly declare active leisure activities. The objective of this study was to evaluate the effect of motor function improvement program implemented in sanatorium on functional condition and functional status of patients suffered from spinal degenerative diseases. Methods. The studies were carried out once in a group of 46 patients aged above 60 in Solanki Inowrocław health resort. The assessment was made based on a questionnaire. Moreover, assessment of pain in the lumbar spine according to thee VAS was made along with evaluation of lumbar spine mobility using Zebris MLS. Results. Evaluation of patients in terms of free time spending have showed that more than half of patients spent their free time actively (57%. The intensity of pain according to the VAS, during flexion, extension, rotation in both direction and lateral flexion of the spine, was decreased at the end of therapy. Flexion, extension and rotation in the right sight increase when Zebris MLS was used before and after therapy. Rotation to the left and lateral flexion to the left were not change. Conclusion. Rehabilitation in sanatorium mobilizes physical activity of patients. It improves the physical activity by significant increase in the motion range of the spine. It exerts a significant analgesic effect.

Simultaneous rotational and vibrational CARS generation through a multiple-frequency combination technique

International Nuclear Information System (INIS)

Alden, M.; Bengtsson, P.E.; Edner, H.

1987-01-01

One most promising laser technique for probing combustion processes is coherent anti-Stokes Raman scattering (CARS), which due to its coherent nature and signal strength is applied in several real-world applications. Until today almost all CARS experiments are based on probing the population of molecular vibrational energy levels. However, there are several reasons rotational CARS, i.e. probing of rotational energy levels, may provide a complement to or even a better choice than vibrational CARS. Recently an alternative way to produce rotational CARS spectra is proposed, which is based on a multiple-frequency combination technique. The energy-level diagram for this process is presented. Two dye laser beams at ω/sub r/, and one fix frequency laser beam at ω/sub g/ are employed. ω/sub r,1/ and ω/sub r,2/ are two frequencies of many possible pairs with a frequency difference matching a rotational transition in a molecule. The excitation induced by ω/sub r,1/ and ω/sub r,2/ is then scattered by the narrowband ω/sub g/ beam resulting in a CARS beam ω/sub g/ at ω/sub g/ + ω/sub r,1/ - ω/sub r,2/. An interesting feature with this technique is that it is possible to generate simultaneously a rotational and vibrational CARS spectrum by using a double-folded boxcars phase matching approach. The authors believe that the proposed technique for producing rotational and vibration CARS spectra could be of interest, e.g., when measuring in highly turbulent flows. In this case the rotational CARS spectra could use for temperature measurements in the cooler parts, whereas vibrational CARS are to be preferred when measuring in the hotter parts

Mirrored and rotated stimuli are not the same: A neuropsychological and lesion mapping study.

Science.gov (United States)

Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Champmartin, Cécile; Pouliquen, Dorothée; Cruypeninck, Yohann; Hannequin, Didier; Gérardin, Emmanuel

2016-05-01

Agnosia for mirrored stimuli is a rare clinical deficit. Only eight patients have been reported in the literature so far and little is known about the neural substrates of this agnosia. Using a previously developed experimental test designed to assess this agnosia, namely the Mirror and Orientation Agnosia Test (MOAT), as well as voxel-lesion symptom mapping (VLSM), we tested the hypothesis that focal brain-injured patients with right parietal damage would be impaired in the discrimination between the canonical view of a visual object and its mirrored and rotated images. Thirty-four consecutively recruited patients with a stroke involving the right or left parietal lobe have been included: twenty patients (59%) had a deficit on at least one of the six conditions of the MOAT, fourteen patients (41%) had a deficit on the mirror condition, twelve patients (35%) had a deficit on at least one the four rotated conditions and one had a truly selective agnosia for mirrored stimuli. A lesion analysis showed that discrimination of mirrored stimuli was correlated to the mesial part of the posterior superior temporal gyrus and the lateral part of the inferior parietal lobule, while discrimination of rotated stimuli was correlated to the lateral part of the posterior superior temporal gyrus and the mesial part of the inferior parietal lobule, with only a small overlap between the two. These data suggest that the right visual 'dorsal' pathway is essential for accurate perception of mirrored and rotated stimuli, with a selective cognitive process and anatomical network underlying our ability to discriminate between mirrored images, different from the process of discriminating between rotated images. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biomechanical comparison of a new stand-alone anterior lumbar interbody fusion cage with established fixation techniques – a three-dimensional finite element analysis

Directory of Open Access Journals (Sweden)

Hsieh Pang-Hsing

2008-06-01

Full Text Available Abstract Background Initial promise of a stand-alone interbody fusion cage to treat chronic back pain and restore disc height has not been realized. In some instances, a posterior spinal fixation has been used to enhance stability and increase fusion rate. In this manuscript, a new stand-alone cage is compared with conventional fixation methods based on the finite element analysis, with a focus on investigating cage-bone interface mechanics and stress distribution on the adjacent tissues. Methods Three trapezoid 8° interbody fusion cage models (dual paralleled cages, a single large cage, or a two-part cage consisting of a trapezoid box and threaded cylinder were created with or without pedicle screws fixation to investigate the relative importance of the screws on the spinal segmental response. The contact stress on the facet joint, slip displacement of the cage on the endplate, and rotational angle of the upper vertebra were measured under different loading conditions. Results Simulation results demonstrated less facet stress and slip displacement with the maximal contact on the cage-bone interface. A stand-alone two-part cage had good slip behavior under compression, flexion, extension, lateral bending and torsion, as compared with the other two interbody cages, even with the additional posterior fixation. However, the two-part cage had the lowest rotational angles under flexion and torsion, but had no differences under extension and lateral bending. Conclusion The biomechanical benefit of a stand-alone two-part fusion cage can be justified. This device provided the stability required for interbody fusion, which supports clinical trials of the cage as an alternative to circumferential fixations.

The impact of office chair features on lumbar lordosis, intervertebral joint and sacral tilt angles: a radiographic assessment.

Science.gov (United States)

De Carvalho, Diana; Grondin, Diane; Callaghan, Jack

2017-10-01

The purpose of this study was to determine which office chair feature is better at improving spine posture in sitting. Participants (n = 28) were radiographed in standing, maximum flexion and seated in four chair conditions: control, lumbar support, seat pan tilt and backrest with scapular relief. Measures of lumbar lordosis, intervertebral joint angles and sacral tilt were compared between conditions and sex. Sitting consisted of approximately 70% of maximum range of spine flexion. No differences in lumbar flexion were found between the chair features or control. Significantly more anterior pelvic rotation was found with the lumbar support (p = 0.0028) and seat pan tilt (p < 0.0001). Males had significantly more anterior pelvic rotation and extended intervertebral joint angles through L1-L3 in all conditions (p < 0.0001). No one feature was statistically superior with respect to minimising spine flexion, however, seat pan tilt resulted in significantly improved pelvic posture. Practitioner Summary: Seat pan tilt, and to some extent lumbar supports, appear to improve seated postures. However, sitting, regardless of chair features used, still involves near end range flexion of the spine. This will increase stresses to the spine and could be a potential injury generator during prolonged seated exposures.

Physics of Rotating and Expanding Black Hole Universe

Directory of Open Access Journals (Sweden)

Seshavatharam U. V. S.

2010-04-01

Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole's temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking's black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is "no cosmic temperature" if there is "no cosmic rotation". Starting from the Planck scale it is assumed that universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation "rate of decrease" in temperature or "rate of increase" in cosmic red shift is a measure of "rate of cosmic expansion". Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to $2.726^circ$ K, smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is $2.726^circ$ K, present value of obtained angular velocity is $2.17 imes 10^{-18}$ rad/sec $cong$ 67 Km/sec$imes$Mpc. Present cosmic mass density and cosmic time are fitted with a $ln (volume ratio$ parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.

Comparison of 2 surgical techniques for reconstructing posterolateral corner of the knee: a cadaveric study evaluated by navigation system.

Science.gov (United States)

Ho, Eric Po-Yan; Lam, Mak-Ham; Chung, Mandy Man-Ling; Fong, Daniel Tik-Pui; Law, Billy Kan-Yip; Yung, Patrick Shu-Hang; Chan, Wood-Yee; Chan, Kai-Ming

2011-01-01

This study aimed to evaluate the immediate effect on knee kinematics by 2 different techniques of posterolateral corner (PLC) reconstruction. Five intact formalin-preserved cadaveric knees were used in this study. A navigation system was used to measure knee kinematics (posterior translation, varus angulation, and external rotation) after application of a constant force and torque to the tibia. Four different conditions of the knee were evaluated during the biomechanical test: intact knee and PLC-sectioned knee and PLC-reconstructed knee by the double-femoral tunnel technique and single-femoral tunnel technique. Sectioning of the PLC structures resulted in significant increases in external rotation at 30° of flexion from 11.2° (SD, 2.6) to 24.6° (SD, 6.2), posterior translation at 30° of flexion from 3.4 mm (SD, 1.5) to 7.4 mm (SD, 3.8), and varus angulation at 0° of flexion from 2.3° (SD, 2.1) to 7.9° (SD, 5.1). Both reconstruction techniques significantly restored the varus stability. The external rotation and posterior translation at 30° of flexion after reconstruction with the double-femoral tunnel technique were 10.2° (SD, 1.3) and 3.4° (SD, 2.7), respectively, which were significantly better than those of the single-femoral tunnel technique. Both techniques of reconstruction showed improved stability compared with PLC-sectioned knees. The double-femoral tunnel technique in PLC reconstruction showed better rotational stability and resistance to posterior translation than the single-femoral tunnel technique without compromising varus stability. PLC reconstruction by a double-femoral tunnel technique achieves better rotational control and resistance to posterior translation. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Evaluation of instability after transtrochanteric anterior rotational osteotomy for nontraumatic osteonecrosis of the femoral head

International Nuclear Information System (INIS)

Hiranuma, Yasunari; Atsumi, Takashi; Kajiwara, Toshihisa; Tamaoki, Satoshi; Asakura, Yasuhiro

2009-01-01

Transtrochanteric anterior rotational osteotomy results in improvement of joint congruity and prevention of progressive collapse and osteoarthritic changes in patients with femoral head osteonecrosis. However, this procedure remains controversial for patients with extensive collapse due to potential osteoarthritis caused by postoperative instability. The purpose of this study was to evaluate hip instability after osteotomy and determine the relation between instability and radiological and clinical outcomes. In all, 27 hips of 24 patients that were followed up for a mean period of 3.8 years were included. Instability was defined as more than 1 mm translation of the femoral head in transverse computed tomography scans obtained at 0 deg and 45 deg flexion of the hip joint. Hips were divided into instability and stability groups. Eleven hips (40%) developed instability after surgery. Osteophytes on the femoral head in 10 hips of the instability group and 2 hips of the stability group had increased in size at follow-up. There was a significant relation between postoperative instability and osteophyte formation. Joint space narrowing was not seen in any of the cases. There was no significant difference between the groups in either the postoperative intact ratio of the femoral head or the Japanese Orthopaedic Association hip score. Neither instability nor osteophyte formation on the femoral head after transtrochanteric anterior rotational osteotomy correlated with progressive osteoarthritic changes or clinical outcome in the presence of an adequate femoral head intact ratio facing the weight-bearing area. (author)

Nuclear elasticity applied to giant resonances of fast rotating nuclei

International Nuclear Information System (INIS)

Jang, S.; Bouyssy, A.

1987-06-01

Isoscalar giant resonances in fast rotating nuclei are investigated within the framework of nuclear elasticity by solving the equation of motion of elastic nuclear medium in a rotating frame of reference. Both Coriolis and centrifugal forces are taken into account. The nuclear rotation removes completely the azimuthal degeneracy of the giant resonance energies. Realistic large values of the angular velocity, which are still small as compared to the giant resonance frequencies, are briefly reviewed in relation to allowed high angular momenta. It is shown that for the A=150 region, the Coriolis force is dominating for small values (< ∼ 0.05) of the ratio of angular velocity to resonance frequency, whereas the centrifugal force plays a prominent part in the shift of the split resonance energies for larger values of the ratio. Typical examples of the resonance energies and their fragmentation due to both rotation and deformation are given

A NEW CLINICAL MUSCLE FUNCTION TEST FOR ASSESSMENT OF HIP EXTERNAL ROTATION STRENGTH: AUGUSTSSON STRENGTH TEST.

Science.gov (United States)

Augustsson, Jesper

2016-08-01

Dynamic clinical tests of hip strength applicable on patients, non-athletes and athletes alike, are lacking. The aim of this study was therefore to develop and evaluate the reliability of a dynamic muscle function test of hip external rotation strength, using a novel device. A second aim was to determine if gender differences exist in absolute and relative hip strength using the new test. Fifty-three healthy sport science students (34 women and 19 men) were tested for hip external rotation strength using a device that consisted of a strap connected in series with an elastic resistance band loop, and a measuring tape connected in parallel with the elastic resistance band. The test was carried out with the subject side lying, positioned in 45 ° of hip flexion and the knees flexed to 90 ° with the device firmly fastened proximally across the knees. The subject then exerted maximal concentric hip external rotation force against the device thereby extending the elastic resistance band. The displacement achieved by the subject was documented by the tape measure and the corresponding force production was calculated. Both right and left hip strength was measured. Fifteen of the subjects were tested on repeated occasions to evaluate test-retest reliability. No significant test-retest differences were observed. Intra-class correlation coefficients ranged 0.93-0.94 and coefficients of variation 2.76-4.60%. In absolute values, men were significantly stronger in hip external rotation than women (right side 13.2 vs 11.0 kg, p = 0.001, left side 13.2 vs 11.5 kg, p = 0.002). There were no significant differences in hip external rotation strength normalized for body weight (BW) between men and women (right side 0.17 kg/BW vs 0.17 kg/BW, p = 0.675, left side 0.17 kg/BW vs 0.18 kg/BW, p = 0.156). The new muscle function test showed high reliability and thus could be useful for measuring dynamic hip external rotation strength in patients, non-athletes and athletes

Study on the Contra-Rotating Propeller system design and full-scale performance prediction method

Directory of Open Access Journals (Sweden)

Keh-Sik Min

2009-09-01

Full Text Available A ship's screw-propeller produces thrust by rotation and, at the same time, generates rotational flow behind the propeller. This rotational flow has no contribution to the generation of thrust, but instead produces energy loss. By recovering part of the lost energy in the rotational flow, therefore, it is possible to improve the propulsion efficiency. The contra-rotating propeller (CRP system is the representing example of such devices. Unfortunately, however, neither a design method nor a full-scale performance prediction procedure for the CRP system has been well established yet. The authors have long performed studies on the CRP system, and some of the results from the authors’ studies shall be presented and discussed.

Asteroid rotation rates

International Nuclear Information System (INIS)

Binzel, R.P.; Farinella, P.

1989-01-01

Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

Refined finite element modelling for the vibration analysis of large rotating machines: Application to the gas turbine modular helium reactor power conversion unit

International Nuclear Information System (INIS)

Combescure, D.; Lazarus, A.; Lazarus, A.

2008-01-01

This paper is aimed at presenting refined finite element modelling used for dynamic analysis of large rotating machines. The first part shows an equivalence between several levels of modelling: firstly, models made of beam elements and rigid disc with gyroscopic coupling representing the position of the rotating shaft in an inertial frame; secondly full three-dimensional (3D) or 3D shell models of the rotor and the blades represented in the rotating frame and finally two-dimensional (2D) Fourier model for both rotor and stator. Simple cases are studied to better understand the results given by analysis performed using a rotating frame and the equivalence with the standard calculations with beam elements. Complete analysis of rotating machines can be performed with models in the frames best adapted for each part of the structure. The effects of several defects are analysed and compared with this approach. In the last part of the paper, the modelling approach is applied to the analysis of the large rotating shaft part of the power conversion unit of the GT-MHR nuclear reactor. (authors)

Refined finite element modelling for the vibration analysis of large rotating machines: Application to the gas turbine modular helium reactor power conversion unit

Energy Technology Data Exchange (ETDEWEB)

Combescure, D.; Lazarus, A. [CEA Saclay, DEN/DM2S/SEMT/DYN, Dynam Anal Lab, Saclay, (France); Lazarus, A. [Ecole Polytech, Mecan Solides Lab, F-91128 Palaiseau, (France)

2008-07-01

This paper is aimed at presenting refined finite element modelling used for dynamic analysis of large rotating machines. The first part shows an equivalence between several levels of modelling: firstly, models made of beam elements and rigid disc with gyroscopic coupling representing the position of the rotating shaft in an inertial frame; secondly full three-dimensional (3D) or 3D shell models of the rotor and the blades represented in the rotating frame and finally two-dimensional (2D) Fourier model for both rotor and stator. Simple cases are studied to better understand the results given by analysis performed using a rotating frame and the equivalence with the standard calculations with beam elements. Complete analysis of rotating machines can be performed with models in the frames best adapted for each part of the structure. The effects of several defects are analysed and compared with this approach. In the last part of the paper, the modelling approach is applied to the analysis of the large rotating shaft part of the power conversion unit of the GT-MHR nuclear reactor. (authors)

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

2001-01-01

In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong ...... approximations to the Riemannian metric, and that the subsequent corrections are inherent in the least squares estimation.......In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Physics of Rotating and Expanding Black Hole Universe

Directory of Open Access Journals (Sweden)

Seshavatharam U. V. S.

2010-04-01

Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole’s temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking’s black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is “no cosmic temperature” if there is “no cosmic rotation”. Starting from the Planck scale it is assumed that- universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation “rate of decrease” in temperature or “rate of increase” in cosmic red shift is a measure of “rate of cosmic expansion”. Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to 2 : 726 K ; smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is 2 : 726 K, present value of obtained angular velocity is 2 : 17 10 Present cosmic mass density and cosmic time are fitted with a ln ( volume ratio parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.

Internal- and External-Rotation Peak Toque in Little League Baseball Players With Subacromial Impingement Syndrome: Improved by Closed Kinetic Chain Shoulder Training.

Science.gov (United States)

Lee, Dong-Rour; Kim, Laurentius Jongsoon

2016-08-01

Many studies have explored closed kinetic chain (CKC) shoulder exercises (SEs) with a sling because they are safer and more effective than open-chain exercises, especially in early stages of treatment. However, the application of CKC SE in youth baseball players has rarely been attempted, although teenage baseball players also experience shoulder pain. To investigate the effects of CKC SE on the peak torque of shoulder internal rotation (IR) and external rotation (ER) in youth baseball players. Single-group pretest, posttest. Biomechanics laboratory. 23 Little League Baseball players with subacromial impingement syndrome. The CKC SE with a sling was CKC shoulder-flexion exercise, extension exercise, IR exercise, and ER exercise. This exercise regimen was conducted 2 or 3 times/wk for 8 wk. The peak torque of shoulder IR and ER was measured using an isokinetic dynamometer. Concentric shoulder rotation was performed, with 5 repetitions at an angular velocity of 60°/s and 15 at 180°/s. The IR and ER peak torque significantly increased at each angular velocity after the exercise program. In particular, the increase in IR and ER peak torque values was statistically significant at an angular velocity of 180°/s. CKC SE was effective in increasing shoulder IR and ER strength, demonstrating its potential benefits in the prevention and treatment of shoulder injury. In addition, increased IR peak torque appears to improve throwing velocity in baseball players.

Mechanical Simulation of the Extension and Flexion of the Elbow Joint in Rehabilitation

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Iman Vahdat

2013-01-01

Full Text Available Objective: The goal of the present study was to improve the extension and flexion of the elbow joint for rehabilitation purposes, in terms of energy dissipation and of injuries caused by stress imposed on connective tissue by exercise equipments during force transfer , by investigation of viscoelastic property variations during change in speed of motion. Materials & Methods: A sample of five men without any previous neuromuscular impairment of the elbow joint was chosen by the BMI factor. The passive continuous motion test (CPM was performed by the CYBEX isokinetic system in the extension and flexion movements of the elbow joint of the left hand, at 4 different speeds (15, 45, 75 and120 Deg/s during 5 consecutive cycles at the range of motion of about 0 to 130 degrees. The experimental data was exported to the MATLAB software for analysis. In order to determine viscoelastic property effects and biomechanical parameters, we used a passive viscoelastic mechanical model constructed by 3 elements for simulation, and also we used the curve fitting method to derive the elastic and viscose coefficients for the model.,. Results: Results of experiments showed that by increasing the speed of motion, the value of work done, hysteresis and elastic coefficient increased and the value of viscose coefficient decreased. Also, it appeared that by increasing the speed of motion, the effect of viscose resistance on the passive torque curves increased. In addition, there was significant correlation between the action of the mechanical model and the action of the concerned limbs, during the movement. Conclusion: It was concluded that in order to improve motion and to reduce imposed risks and injuries to joints and limbs, rehabilitation exercises better be performed at lower speeds and with rehabilitation equipments supported by viscoelastic resistant force.

[Biomechanics changes of lumbar spine caused by foraminotomy via percutaneous transforaminal endoscopic lumbar discectomy].

Science.gov (United States)

Qian, J; Yu, S S; Liu, J J; Chen, L; Jing, J H

2018-04-03

Objective: To analyze the biomechanics changes of lumbar spine caused by foraminotomy via percutaneous transforaminal endoscopic lumbar discectomy using the finite element method. Methods: Three healthy adult males (aged 35.6 to 42.3 years) without spinal diseases were enrolled in this study and 3D-CT scans were carried out to obtain the parameters of lumbar spine. Mimics software was applied to build a 3D finite element model of lumbar spine. Graded resections (1/4, 2/4, 3/4 and 4/4) of the left superior articular process of L(5) were done via percutaneous transforaminal endoscopic lumbar discectomy. Then, the pressure of the L(4/5) right facets, the pressure of the L(4/5) intervertebral disc and the motion of lumbar spine were recorded after simulating the normal flexion and extension, lateral flexion and rotation of the lumbar spine model during different resections. The data were compared among groups with analysis of variance. Results: Comparing with the normal group, after 1/4 resection of the left superior articular process of L(5), the pressure of the L(4/5) right facets showed significant differences during left lateral flexion and rotation of lumbar spine ( q =8.823, 8.248, both P biomechanics and the stability of lumbar spine changed partly after 1/4 resection of the superior articular process and obviously after more than 2/4 is resected. The superior articular process should be paid more attention during foraminotomy via percutaneous transforaminal endoscopic lumbar discectomy.

Age-related decreases in motor unit discharge rate and force control during isometric plantar flexion

DEFF Research Database (Denmark)

Kallio, J; Søgaard, Karen; Avela, J

2012-01-01

Aging is related to multiple changes in muscle physiology and function. Previous findings concerning the effects of aging on motor unit discharge rate (DR) and fluctuations in DR and force are somewhat contradictory. Eight YOUNG and nine OLD physically active males performed isometric ramp (RECR......) and isotonic (ISO) plantar flexions at 10 and 20% of surface EMG at MVC. Motor unit (MU) action potentials were recorded with intramuscular fine-wire electrodes and decomposed with custom build software "Daisy". DR was lower in OLD in RECR-10% (17.9%, p...

The bending stiffness of shoes is beneficial to running energetics if it does not disturb the natural MTP joint flexion.

Science.gov (United States)

Oh, Keonyoung; Park, Sukyung

2017-02-28

A local minimum for running energetics has been reported for a specific bending stiffness, implying that shoe stiffness assists in running propulsion. However, the determinant of the metabolic optimum remains unknown. Highly stiff shoes significantly increase the moment arm of the ground reaction force (GRF) and reduce the leverage effect of joint torque at ground push-off. Inspired by previous findings, we hypothesized that the restriction of the natural metatarsophalangeal (MTP) flexion caused by stiffened shoes and the corresponding joint torque changes may reduce the benefit of shoe bending stiffness to running energetics. We proposed the critical stiffness, k cr , which is defined as the ratio of the MTP joint (MTPJ) torque to the maximal MTPJ flexion angle, as a possible threshold of the elastic benefit of shoe stiffness. 19 subjects participated in a running test while wearing insoles with five different bending stiffness levels. Joint angles, GRFs, and metabolic costs were measured and analyzed as functions of the shoe stiffness. No significant changes were found in the take-off velocity of the center of mass (CoM), but the horizontal ground push-offs were significantly reduced at different shoe stiffness levels, indicating that complementary changes in the lower-limb joint torques were introduced to maintain steady running. Slight increases in the ankle, knee, and hip joint angular impulses were observed at stiffness levels exceeding the critical stiffness, whereas the angular impulse at the MTPJ was significantly reduced. These results indicate that the shoe bending stiffness is beneficial to running energetics if it does not disturb the natural MTPJ flexion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rotator cuff exercises

Science.gov (United States)

... 25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder MRI scan Shoulder pain Patient Instructions Rotator cuff - self-care Shoulder surgery - discharge Using your ...

Muscle releases to improve passive motion and relieve pain in patients with spastic hemiplegia and elbow flexion contractures.

Science.gov (United States)

Namdari, Surena; Horneff, J Gabe; Baldwin, Keith; Keenan, Mary Ann

2012-10-01

Patients with spastic hemiplegia after upper motor neuron (UMN) injury can develop elbow contractures. This study evaluated outcomes of elbow releases in treating spastic elbow flexion contractures in hemiplegic patients. Adults with spastic hemiplegia due to UMN injury who underwent elbow releases (brachialis, brachioradialis, and biceps muscles) were included. Nonoperative treatment was unsuccessful in all patients. Patients complained of difficulty with passive functions. Passive range of motion (ROM), pain relief, Modified Ashworth spasticity score, and complications were evaluated preoperatively and postoperatively. There were 8 men and 21 women with an average age of 52.4 years (range, 24.1-81.4 years). Seventeen patients had pain preoperatively. Postoperative follow-up was a mean of 1.7 years (range, 1-4.5 years). Preoperatively, patients lacked a mean of 78° of passive elbow extension compared with 17° postoperatively (P .05). Releases of the brachialis, brachioradialis, and biceps muscles can be an effective means of pain relief, improved passive ROM, and decreased spasticity in patients with elbow flexion deformity after UMN injury. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Réflexion sur l’origine du processus de segmentation du marche du travail

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Attia Nicole

2006-01-01

Full Text Available (francuski Ce travail propose une réflexion sur l'origine du processus de segmentation du marché du travail par rapport à l'entreprise. Se situe-t-elle au sein même de l'entreprise ou en amont, c'est à dire entre les entreprises? Cela revient à se demander si on peut avoir une approche microéconomique ou macroéconomique de la segmentation et, à s'interroger sur le rôle réel tenu par les firmes dans le processus. Déterminant pour la théorie, ce rôle est à repenser selon la réponse apportée à notre question.

Determination of concentric and eccentric peak moment values for trunk flexion and extension in sedentary asymptomatic individuals by isokinetic dynamometry: a pilot study

Directory of Open Access Journals (Sweden)

Rafaella Stradiotto Bernardelli

2017-11-01

Full Text Available The spine has a direct influence on postural alignment and movement of the whole body. Lumbar muscles constitute a critical element in trunk performance while weakness of these muscles has been associated with low back pain. Hence, strength profiling of trunk muscles is clinically significant. The objective of this research was to determine, by means of isokinetic dynamometry, peak moment (PM values during isokinetic concentric and eccentric efforts of trunk flexion and extension in sedentary asymptomatic individuals. The sample consisted of 100 asymptomatic sedentary volunteers, fifty from each sex, aging 22.2 ± 3.3 years old. The sample underwent concentric and eccentric isokinetic assessment of the trunk flexor and extensor muscles at an angular velocity of 60 degrees/sec for each mode of contraction. The mean concentric PM for trunk flexion and extension were 139.5 and 166.6 Nm, respectively, while the respective values for the eccentric efforts were 188.8 and 221.2 Nm. The PM flexion/extension ratio was 0.87 and 0.89 for the concentric and eccentric efforts, respectively. These values of concentric and eccentric PM and PM ratio will serve as comparison parameters for future research, as well as for the assessment of symptomatic patients, and to help in the creation of the trunk muscle rebalance protocols.

Evaluation experimentale et theorique du comportement a la flexion de nouveaux poteaux en materiaux composites

Science.gov (United States)

Metiche, Slimane

La demande croissante en poteaux pour les differents reseaux d'electricite et de telecommunications a rendu necessaire l'utilisation de materiaux innovants, qui preservent l'environnement. La majorite des poteaux electriques existants au Canada ainsi qu'a travers le monde, sont fabriques a partir de materiaux traditionnels tel que le bois, le beton ou l'acier. Les motivations des industriels et des chercheurs a penser a d'autres solutions sont diverses, citons entre autre: La limitation en longueur des poteaux en bois ainsi que la vulnerabilite des poteaux fabriques en beton ou en acier aux agressions climatiques. Les nouveaux poteaux en materiaux composites se presentent comme de bons candidats a cet effet, cependant; leur comportement structural n'est pas connu et des etudes theoriques et experimentales approfondies sont necessaires avant leur mise en marche a grande echelle. Un programme de recherche intensif comportant plusieurs projets experimentaux, analytiques et numeriques est en cours a l'Universite de Sherbrooke afin d'evaluer le comportement a court et a long termes de ces nouveaux poteaux en Polymeres Renforces de Fibres (PRF). C'est dans ce contexte que s'inscrit la presente these, et notre recherche vise a evaluer le comportement a la flexion de nouveaux poteaux tubulaires coniques fabriques en materiaux composites par enroulement filamentaire et ce, a travers une etude theorique, ainsi qu'a travers une serie d'essais de flexion en "grandeur reelle" afin de comprendre le comportement structural de ces poteaux, d'optimiser la conception et de proposer une procedure de dimensionnement pour les utilisateurs. Les poteaux en Polymeres Renforces de Fibres (PRF) etudies dans cette these sont fabriques avec une resine epoxyde renforcee de fibres de verre type E. Chaque type poteaux est constitue principalement de trois zones ou les proprietes geometriques (epaisseur, diametre) et les proprietes mecaniques sont differentes d'une zone a l'autre. La difference

Post-Cam Design and Contact Stress on Tibial Posts in Posterior-Stabilized Total Knee Prostheses: Comparison Between a Rounded and a Squared Design.

Science.gov (United States)

Watanabe, Toshifumi; Koga, Hideyuki; Horie, Masafumi; Katagiri, Hiroki; Sekiya, Ichiro; Muneta, Takeshi

2017-12-01

The post-cam mechanism in posterior stabilized (PS) prostheses plays an important role in total knee arthroplasty (TKA). The purpose of this study is to clarify the difference of the contact stress on the tibial post between a rounded post-cam design and a squared design during deep knee flexion and at hyperextension using the three-dimensional (3D) finite element models. We created 2 types of 3D, finite element models of PS prostheses (types A and B), whose surfaces were identical except for the post-cam geometries: type A has a rounded post-cam design, while type B has a squared design. Both types have a similar curved-shape intercondylar notch of the femoral component. Stress distributions, peak contact stresses, and contact areas on the tibial posts at 90°, 120°, and 150° flexion with/without 10° tibial internal rotation and at 10° hyperextension were compared between the 2 models. Type B demonstrated more concentrated stress distribution compared to type A. The peak contact stresses were similar in both groups during neutral flexion; however, the stresses were much higher in type B during flexion with 10° rotation and at hyperextension. The higher peak contact stresses corresponded to the smaller contact areas in the tibial post. A rounded post-cam design demonstrated less stress concentration during flexion with rotation and at hyperextension compared with a squared design. The results would be useful for development of implant designs and prediction of the contact stress on the tibial post in PS total knee arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

A randomized clinical trial to compare the immediate effects of seated thoracic manipulation and targeted supine thoracic manipulation on cervical spine flexion range of motion and pain.

Science.gov (United States)

Karas, Steve; Olson Hunt, Megan J

2014-05-01

Randomized clinical trial. To determine the effectiveness of seated thoracic manipulation versus targeted supine thoracic manipulation on cervical spine pain and flexion range of motion (ROM). There is evidence that thoracic spine manipulation is an effective treatment for patients with cervical spine pain. This evidence includes a variety of techniques to manipulate the thoracic spine. Although each of them is effective, no research has compared techniques to determine which produces the best outcomes. A total of 39 patients with cervical spine pain were randomly assigned to either a seated thoracic manipulation or targeted supine thoracic manipulation group. Pain and flexion ROM measures were taken before and after the intervention. Pain reduction (post-treatment-pre-treatment) was significantly greater in those patients receiving the targeted supine thoracic manipulation compared to the seated thoracic manipulation (Pmanipulation group. The results of this study indicate that a targeted supine thoracic manipulation may be more effective in reducing cervical spine pain and improving cervical flexion ROM than a seated thoracic manipulation. Future studies should include a variety of patients and physical therapists (PTs) to validate our findings.

Pathophysiological and behavioral deficits in developing mice following rotational acceleration-deceleration traumatic brain injury

Directory of Open Access Journals (Sweden)

Guoxiang Wang

2018-01-01

Full Text Available Abusive head trauma (AHT is the leading cause of death from trauma in infants and young children. An AHT animal model was developed on 12-day-old mice subjected to 90° head extension-flexion sagittal shaking repeated 30, 60, 80 and 100 times. The mortality and time until return of consciousness were dependent on the number of repeats and severity of the injury. Following 60 episodes of repeated head shakings, the pups demonstrated apnea and/or bradycardia immediately after injury. Acute oxygen desaturation was observed by pulse oximetry during respiratory and cardiac suppression. The cerebral blood perfusion was assessed by laser speckle contrast analysis (LASCA using a PeriCam PSI system. There was a severe reduction in cerebral blood perfusion immediately after the trauma that did not significantly improve within 24 h. The injured mice began to experience reversible sensorimotor function at 9 days postinjury (dpi, which had completely recovered at 28 dpi. However, cognitive deficits and anxiety-like behavior remained. Subdural/subarachnoid hemorrhage, damage to the brain-blood barrier and parenchymal edema were found in all pups subjected to 60 insults. Proinflammatory response and reactive gliosis were upregulated at 3 dpi. Degenerated neurons were found in the cerebral cortex and olfactory tubercles at 30 dpi. This mouse model of repetitive brain injury by rotational head acceleration-deceleration partially mimics the major pathophysiological and behavioral events that occur in children with AHT. The resultant hypoxia/ischemia suggests a potential mechanism underlying the secondary rotational acceleration-deceleration-induced brain injury in developing mice.

Spin currents of charged Dirac particles in rotating coordinates

Science.gov (United States)

Dayi, Ö. F.; Yunt, E.

2018-03-01

The semiclassical Boltzmann transport equation of charged, massive fermions in a rotating frame of reference, in the presence of external electromagnetic fields is solved in the relaxation time approach to establish the distribution function up to linear order in the electric field in rotating coordinates, centrifugal force and the derivatives. The spin and spin current densities are calculated by means of this distribution function at zero temperature up to the first order. It is shown that the nonequilibrium part of the distribution function yields the spin Hall effect for fermions constrained to move in a plane perpendicular to the angular velocity and magnetic field. Moreover it yields an analogue of Ohm's law for spin currents whose resistivity depends on the external magnetic field and the angular velocity of the rotating frame. Spin current densities in three-dimensional systems are also established.

Spin imaging in solids using synchronously rotating field gradients and samples

International Nuclear Information System (INIS)

Wind, R.A.; Yannoni, C.S.

1983-01-01

A method for spin-imaging in solids using nuclear magnetic resonance (NMR) spectroscopy is described. With this method, the spin density distribution of a two- or three-dimensional object such as a solid can be constructed resulting in an image of the sample. This method lends itself to computer control to map out an image of the object. This spin-imaging method involves the steps of placing a solid sample in the rf coil field and the external magnetic field of an NMR spectrometer. A magnetic field gradient is superimposed across the sample to provide a field gradient which results in a varying DC field that has different values over different parts of the sample. As a result, nuclei in different parts of the sample have different resonant NMR frequencies. The sample is rotated about an axis which makes a particular angle of 54.7 degrees with the static external magnetic field. The magnetic field gradient which has a spatial distribution related to the sample spinning axis is then rotated synchronously with the sample. Data is then collected while performing a solid state NMR line narrowing procedure. The next step is to change the phase relation between the sample rotation and the field gradient rotation. The data is again collected as before while the sample and field gradient are synchronously rotated. The phase relation is changed a number of times and data collected each time. The spin image of the solid sample is then reconstructed from the collected data

Age-Related Differences in Motor Coordination during Simultaneous Leg Flexion and Finger Extension: Influence of Temporal Pressure

OpenAIRE

Hussein, Tarek; Yiou, Eric; Larue, Jacques

2013-01-01

Although the effect of temporal pressure on spatio-temporal aspects of motor coordination and posture is well established in young adults, there is a clear lack of data on elderly subjects. This work examined the aging-related effects of temporal pressure on movement synchronization and dynamic stability. Sixteen young and eleven elderly subjects performed series of simultaneous rapid leg flexions in an erect posture paired with ipsilateral index-finger extensions, minimizing the difference b...

Rotating solid foam reactors : mass transfer and reaction rate

NARCIS (Netherlands)

Tschentscher, R.

2012-01-01

In this thesis the performance and applicability of rotating solid foam stirrers is investigated. The stirrer consists, thereby of a solid, highly porous structure, which is used as stirrer and catalyst support simultaneously. The solid foam block occupies a large part of the reactor volume.

The flexion synergy, mother of all synergies and father of new models of gait

Directory of Open Access Journals (Sweden)

Jacques eDuysens

2013-03-01

Full Text Available Recently there has been a growing interest in the modular organization of leg movements, in particular those related to locomotion. One of the basic modules involves the flexion of the leg during swing and it was shown that this module is already present in neonates (Dominici, et al. 2011. In this paper, we question how these finding build upon the original work by Sherrington, who proposed that the flexor reflex is the basic building block of the flexion during swing phase. Similarly, the relation between the flexor reflex and the withdrawal reflex modules of Schouenborg et al. (1994 will be discussed. It will be argued that there is large overlap between these notions on modules and the older concepts of reflexes. In addition, it will be shown that there is a great flexibility in the expression of some of these modules during gait, thereby allowing for a phase-dependent modulation of the appropriate responses. In particular, the end of the stance phase is a period when the flexor synergy is facilitated. It is proposed that this is linked to the activation of circuitry that is responsible for the generation of locomotor patterns (CPG, central pattern generator. More specifically, it is suggested that the responses in that period relate to the activation of a flexor burst generator. The latter structure forms the core of a new asymmetric model of the CPG. This activation is controlled by afferent input (facilitation by a broad range of afferents, suppression by load afferent input. Meanwhile, many of these physiologic features have found their way in the control of very flexible walking bipedal robots.

A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups

Science.gov (United States)

Ruždjak, Domagoj; Brajša, Roman; Sudar, Davor; Skokić, Ivica; Poljančić Beljan, Ivana

2017-12-01

The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differential-rotation parameters A and B. These differential-rotation parameters were compared with the solar-activity level. We found that the Sun rotates more differentially at the minimum than at the maximum of activity during the epoch 1977 - 2016. An inverse correlation between equatorial rotation and solar activity was found using the recently revised sunspot number. The secular decrease of the equatorial rotation rate that accompanies the increase in activity stopped in the last part of the twentieth century. It was noted that when a significant peak in equatorial rotation velocity is observed during activity minimum, the next maximum is weaker than the previous one.

Rotating specimen rack repair

International Nuclear Information System (INIS)

Miller, G.E.; Rogers, P.J.; Nabor, W.G.; Bair, H.

1984-01-01

In 1980, an operator at the UCI TRIGA Reactor noticed difficulties with the rotation of the specimen rack. Investigations showed that the drive bearing in the rack had failed and allowed the bearings to enter the rack. After some time of operation in static mode it was decided that installation of a bearing substitute - a graphite sleeve - would be undertaken. Procedures were written and approved for removal of the rack, fabrication and installation of the sleeve, and re-installation of the rack. This paper describes these procedures in some detail. Detailed drawings of the necessary parts may be obtained from the authors

Gastight Hydrodynamic Electrochemistry: Design for a Hermetically Sealed Rotating Disk Electrode Cell.

Science.gov (United States)

Jung, Suho; Kortlever, Ruud; Jones, Ryan J R; Lichterman, Michael F; Agapie, Theodor; McCrory, Charles C L; Peters, Jonas C

2017-01-03

Rotating disk electrodes (RDEs) are widely used in electrochemical characterization to analyze the mechanisms of various electrocatalytic reactions. RDE experiments often make use of or require collection and quantification of gaseous products. The combination of rotating parts and gaseous analytes makes the design of RDE cells that allow for headspace analysis challenging due to gas leaks at the interface of the cell body and the rotator. In this manuscript we describe a new, hermetically sealed electrochemical cell that allows for electrode rotation while simultaneously providing a gastight environment. Electrode rotation in this new cell design is controlled by magnetically coupling the working electrode to a rotating magnetic driver. Calibration of the RDE using a tachometer shows that the rotation speed of the electrode is the same as that of the magnetic driver. To validate the performance of this cell for hydrodynamic measurements, limiting currents from the reduction of a potassium ferrocyanide (K 4 [Fe(CN) 6 ]·3H 2 O) were measured and shown to compare favorably with calculated values from the Levich equation and with data obtained using more typical, nongastight RDE cells. Faradaic efficiencies of ∼95% were measured in the gas phase for oxygen evolution in alkaline media at an Inconel 625 alloy electrocatalyst during rotation at 1600 rpm. These data verify that a gastight environment is maintained even during rotation.

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1976-01-01

Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

The Columbus Knee System: 4-Year Results of a New Deep Flexion Design Compared to the NexGen Full Flex Implant

Directory of Open Access Journals (Sweden)

D. Goebel

2012-01-01

Full Text Available The Columbus knee system is designed as a standard knee implant to allow high flexion without additional bone resection. Between August, 2004 and March, 2010 we performed 109 total knee arthroplasties of the Columbus knee system in 101 consecutive patients suffering from primary arthrosis of the knee. Mean age was 72.4 years in women and 70.3 years in men. Mean followup was 47.3 months. The 4-year results of a group of patients who received the NexGen Full Flex implant operated by the same surgeon were used for comparison. Mean total knee score was Columbus: 175.6 and NexGen Flex: 183.4; =0.037. Mean operation time was 53 min for Columbus and 66 min for NexGen Flex; 0.05. Radiological assessment showed no signs of loosening for both groups. Therefore, the Columbus knee system can be recommended for flexion angles up to 140∘.

Rotation of the bulge components of barred galaxies

International Nuclear Information System (INIS)

Kormendy, J.

1982-01-01

Stellar rotation and velocity-dispersion measurements are presented for the bulge components of the SBO galaxies NGC 1023, 2859, 2950, 4340, 4371, and 7743. The kinematics of nine SB bulges with data available are compared with bulges of unbarred galaxies studied by Kormendy and Illingworth. All of the SB bulges are found to rotate at least as rapidly as oblate-spheroid dynamical models which are flattened by rotation. This result confirms the conclusion of Kormendy and Illingworth that bulges rotate very rapidly. Six SB bulges found by Kormendy and Koo to be triaxial rotate even more rapidly than the oblate models. In this respect, they resemble published n-body models of bars. That is, triaxial bulges are dynamically like bars and unlike elliptical galaxies, which are also believed to be triaxial, but which rotate slowly. Measured velocity anisotropies are found to be consistent with these conclusions. Two ordinary bulges whose rotation is well described by isotropic modes have a ratio of radial to azimuthal velocity dispersion of sigma/sub r//sigma/sub theta/ = 0.96 +- 0.03. In contrast, the triaxial bulge of NGC 3945, which rotates much faster than the isotropic models, has sigma/sub r//sigma/sub theta/ approx.1.31 +- 0.06. This is similar to the degree of anisotropy, sigma/sub r//sigma/sub theta/approx.1.21 +- 0.03, found in a recent n-body bar model by Hohl and Zang. Altogether the kinematic observations imply the triaxial bulges are more disklike than SA bulges. They appear to have been formed with more dissipation than ordinary bulges. These results are consistent with the hypothesis that part of the bulge in many SB galaxies consists of disk material (i.e., gas) which has been transported to the center by the bar. The resulting star formation may produce a very centrally concentrated light distribution which resembles a bulge but which has dislike dynamics

Rotational Mal-Alignment after Reamed Intramedullary Nailing for tibial shaft fracture.

Science.gov (United States)

Khan, Sher Baz; Mohib, Yasir; Rashid, Rizwan Haroon; Rashid, Haroonur

2016-10-01

Intra-medullary (IM) nailing is standard of care for unstable tibial shaft fractures. Malrotation is very common but it is under-recognised, inpart because of variation in normal anatomy and partly due to difficulty in accurately assessing rotation. This study was planned to evaluate the frequency of rotational mal-alignment after reamed tibia IMnailing. This cross-sectional study was conducted at Aga khan University Hospital, Karachi, and comprised patients with tibia shaft fractures managed with IMnailing from January to December 2014. All the patients were assessed intra-operatively for rotational alignment using the knee and ankle fluoroscopic images. There were 81 patients with a mean age of 38±16.9 years. There were 64(79%) male patients. Overall the incidence of malrotation was in 20(24.7%) cases. Rotational mal-alignment is one of the preventable complications after IMnailing which can be assesed intra-operatively under fluoroscope.

Optimisation of multi-layer rotationally moulded foamed structures

Science.gov (United States)

Pritchard, A. J.; McCourt, M. P.; Kearns, M. P.; Martin, P. J.; Cunningham, E.

2018-05-01

Multi-layer skin-foam and skin-foam-skin sandwich constructions are of increasing interest in the rotational moulding process for two reasons. Firstly, multi-layer constructions can improve the thermal insulation properties of a part. Secondly, foamed polyethylene sandwiched between solid polyethylene skins can increase the mechanical properties of rotationally moulded structural components, in particular increasing flexural properties and impact strength (IS). The processing of multiple layers of polyethylene and polyethylene foam presents unique challenges such as the control of chemical blowing agent decomposition temperature, and the optimisation of cooling rates to prevent destruction of the foam core; therefore, precise temperature control is paramount to success. Long cooling cycle times are associated with the creation of multi-layer foam parts due to their insulative nature; consequently, often making the costs of production prohibitive. Devices such as Rotocooler®, a rapid internal mould water spray cooling system, have been shown to have the potential to significantly decrease cooling times in rotational moulding. It is essential to monitor and control such devices to minimise the warpage associated with the rapid cooling of a moulding from only one side. The work presented here demonstrates the use of threaded thermocouples to monitor the polymer melt in multi-layer sandwich constructions, in order to analyse the cooling cycle of multi-layer foamed structures. A series of polyethylene skin-foam test mouldings were produced, and the effect of cooling medium on foam characteristics, mechanical properties, and process cycle time were investigated. Cooling cycle time reductions of 45%, 26%, and 29% were found for increasing (1%, 2%, and 3%) chemical blowing agent (CBA) amount when using internal water cooling technology from ˜123°C compared with forced air cooling (FAC). Subsequently, a reduction of IS for the same skin-foam parts was found to be 1%, 4

Dual-task and anticipation impact lower limb biomechanics during a single-leg cut with body borne load.

Science.gov (United States)

Seymore, Kayla D; Cameron, Sarah E; Kaplan, Jonathan T; Ramsay, John W; Brown, Tyler N

2017-12-08

This study quantified how a dual cognitive task impacts lower limb biomechanics during anticipated and unanticipated single-leg cuts with body borne load. Twenty-four males performed anticipated and unanticipated cuts with and without a dual cognitive task with three load conditions: no load (∼6 kg), medium load (15% of BW), and heavy load (30% of BW). Lower limb biomechanics were submitted to a repeated measures linear mixed model to test the main and interaction effects of load, anticipation, and dual task. With body borne load, participants increased peak stance (PS) hip flexion (p = .004) and hip internal rotation (p = .001) angle, and PS hip flexion (p = .001) and internal rotation (p = .018), and knee flexion (p = .016) and abduction (p = .001) moments. With the dual task, participants decreased PS knee flexion angle (p biomechanical adaptations thought to increase risk of musculoskeletal injury, but neither anticipation nor dual task exaggerated those biomechanical adaptations. With a dual task, participants adopted biomechanics known to increase injury risk; whereas, participants used lower limb biomechanics thought to decrease injury risk during unanticipated cuts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Helical axes of skeletal knee joint motion during running.

Science.gov (United States)

van den Bogert, A J; Reinschmidt, C; Lundberg, A

2008-01-01

The purpose of this study was to determine the changes in the axis of rotation of the knee that occur during the stance phase of running. Using intracortical pins, the three-dimensional skeletal kinematics of three subjects were measured during the stance phase of five running trials. The stance phase was divided into equal motion increments for which the position and orientation of the finite helical axes (FHA) were calculated relative to a tibial reference frame. Results were consistent within and between subjects. At the beginning of stance, the FHA was located at the midepicondylar point and during the flexion phase moved 20mm posteriorly and 10mm distally. At the time of peak flexion, the FHA shifted rapidly by about 10-20mm in proximal and posterior direction. The angle between the FHA and the tibial transverse plane increased gradually during flexion, to about 15 degrees of medial inclination, and then returned to zero at the start of the extension phase. These changes in position and orientation of FHA in the knee should be considered in analyses of muscle function during human movement, which require moment arms to be defined relative to a functional rotation axis. The finding that substantial changes in axis of rotation occurred independent of flexion angle suggests that musculoskeletal models must have more than one kinematic degree-of-freedom at the knee. The same applies to the design of knee prostheses, if the goal is to restore normal muscle function.

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion.

Directory of Open Access Journals (Sweden)

Yvette L Kerkum

Full Text Available Rigid Ankle-Foot Orthoses (AFOs are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP. While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years were prescribed with a ventral shell spring-hinged AFO (vAFO. The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (p<0.05 was used to analyze the effects of different conditions. Compared to shoes-only, all vAFOs improved the knee angle and net moment similarly. Ankle power generation and work were preserved only by the spring-like vAFOs. All vAFOs decreased the net energy cost compared to shoes-only, but no differences were found between vAFOs, showing that the effects of spring-like vAFOs to promote push-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power

Surface dimpling on rotating work piece using rotation cutting tool

Science.gov (United States)

Bhapkar, Rohit Arun; Larsen, Eric Richard

2015-03-31

A combined method of machining and applying a surface texture to a work piece and a tool assembly that is capable of machining and applying a surface texture to a work piece are disclosed. The disclosed method includes machining portions of an outer or inner surface of a work piece. The method also includes rotating the work piece in front of a rotating cutting tool and engaging the outer surface of the work piece with the rotating cutting tool to cut dimples in the outer surface of the work piece. The disclosed tool assembly includes a rotating cutting tool coupled to an end of a rotational machining device, such as a lathe. The same tool assembly can be used to both machine the work piece and apply a surface texture to the work piece without unloading the work piece from the tool assembly.

PRP as an Adjunct to Rotator Cuff Tendon Repair.

Science.gov (United States)

Barber, F Alan

2018-06-01

Arthroscopic rotator cuff repair is a commonly performed repair. Technical developments provide surgeons the tools to create biomechanically robust repairs. How can the biological response mirror the strong and stable surgery? Platelet-rich plasma (PRP) is a supraphysiological platelet concentration which may positively augment rotator cuff healing. Not all PRPs are the same. High leukocyte levels and thrombin activation may be detrimental to tendon healing. Thrombin activation triggers an immediate release of growth factors and may actually inhibit some parts of the healing response. Clear differences exist between liquid PRP (products released within hours after activation) and solid fibrin PRP which slowly releases factors over days. The heterogenicity data and grouping liquid and solid PRP together make systematic reviews confusing. Solid PRP fibrin constructs are often associated with increased tendon healing. PRP fibrin matrix offers the greatest promise for improving clinical success after rotator cuff tendon repair.

Outcomes following arthroscopic transosseous equivalent suture bridge double row rotator cuff repair: a prospective study and short-term results

Directory of Open Access Journals (Sweden)

Imam Mohamed Abdelnabi

2016-01-01

Full Text Available Background: The transosseous-equivalent cross bridge double row (TESBDR rotator cuff (RC repair technique has been developed to optimize healing biology at a repaired RC tendon insertion. It has been shown in the laboratory to improve pressurized contact area and mean foot print pressure when compared with a double row anchor technique. Pressure has been shown to influence healing between tendon and bone, and the tendon compression vector provided by the transosseous-equivalent suture bridges may enhance healing. The purpose was to prospectively evaluate the outcomes of arthroscopic TESBDR RC repair. Methods: Single center prospective case series study. Sixty-nine patients were selected to undergo arthroscopic TESBDR RC repair and were included in the current study. Primary outcome measures included the Oxford Shoulder Score (OSS, the University of California, Los Angeles (UCLA score, the Constant-Murley (CM Score and Range of motion (ROM. Secondary outcome measures included a Visual Analogue Scale (VAS for pain, another VAS for patient satisfaction from the operative procedure, EuroQoL 5-Dimensions Questionnaire (EQ-5D for quality of life assessment. Results: At 24 months post-operative, average OSS score was 44, average UCLA score was 31, average CM score was 88, average forward flexion was 145°, average internal rotation was 35°, average external rotation was 79°, average abduction was 150°, average EQ-5D score was 0.73, average VAS for pain was 2.3, and average VAS for patient satisfaction was 9.2. Conclusion: Arthroscopic TESBDR RC repair is a procedure with good post-operative functional outcome and low re-tear rate based on a short term follow-up.

The rotating universe

International Nuclear Information System (INIS)

Ruben, G.; Treder, H.J.

1987-01-01

For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

Instability of electromagnetic waves in a self-gravitating rotating magnetized dusty plasma with opposite polarity grains

International Nuclear Information System (INIS)

Shukla, Nitin; Moslem, W. M.; Shukla, P. K.

2007-01-01

By using the two fluid and Maxwell equations, the properties of electromagnetic waves in a rotating positive-negative dusty magnetoplasmas are investigated. It is found that the cross-coupling between the equilibrium dust flows and the perturbed magnetic field produces a Lorentz force that separates positive and negative dust grains. A new dispersion relation is derived and analyzed numerically. The effects of the dust grain radius, the equilibrium streaming speed, Jeans frequency, and the rotational frequency on the behavior of the real and imaginary parts of the wave frequency are examined. It is found that for small dust grain radius, the growth rate (the real frequency) increases (decreases) with the increase of the streaming dust speed and Jeans frequency. However, the dust rotational frequency does not have an important role in this case. For large dust grain radius, only the imaginary part of the wave frequency is presented. It is found that the rotational frequency (Jeans frequency and dust streaming speed) decreases (increase) the growth rate

Decontamination of a rotating cutting tool during operation by means of atmospheric pressure plasmas

DEFF Research Database (Denmark)

Leipold, Frank; Kusano, Yukihiro; Hansen, F.

2010-01-01

, is used for the experiments. A rotating knife was inoculated with L. innocua. The surface of the rotating knife was partly exposed to an atmospheric pressure dielectric barrier discharge operated in air, where the knife itself served as a ground electrode. The rotation of the knife ensures a treatment...... of the whole cutting tool. A log 5 reduction of L. innocua is obtained after 340 s of plasma operation. The temperature of the knife after treatment was found to be below 30 °C. The design of the setup allows a decontamination during slicing operation....

The role of short-rotation woody crops in sustainable development

International Nuclear Information System (INIS)

Shepard, J.P.; Tolbert, V.R.

1996-01-01

One answer to increase wood production is by increasing management intensity on existing timberland, especially in plantation forests. Another is to convert land currently in agriculture to timberland. Short-rotation woody crops can be used in both cases. But, what are the environmental consequences? Short-rotation woody crops can provide a net improvement in environmental quality at both local and global scales. Conversion of agricultural land to short-rotation woody crops can provide the most environmental quality enhancement by reducing erosion, improving soil quality, decreasing runoff, improving groundwater quality, and providing better wildlife habitat. Forest products companies can use increased production from intensively managed short-rotation woody crop systems to offset decreased yield from the portion of their timberland that is managed less intensively, e.g. streamside management zones and other ecologically sensitive or unique areas. At the global scale, use of short-rotation woody crops for bioenergy is part of the solution to reduce greenhouse gases produced by burning fossil fuels. Incorporating short-rotation woody crops into the agricultural landscape also increases storage of carbon in the soil, thus reducing atmospheric concentrations. In addition, use of wood instead of alternatives such as steel, concrete, and plastics generally consumes less energy and produces less greenhouse gases. Cooperative research can be used to achieve energy, fiber, and environmental goals. This paper will highlight several examples of ongoing cooperative research projects that seek to enhance the environmental aspects of short-rotation woody crop systems. Government, industry, and academia are conducting research to study soil quality, use of mill residuals, nutrients in runoff and groundwater, and wildlife use of short-rotation woody crop systems in order to assure the role of short-rotation crops as a sustainable way of meeting society's needs

Simulation of lumbar and neck angle flexion while ingress of paratransit (angkot in Indonesia as a preliminary design study

Directory of Open Access Journals (Sweden)

Yukhi Mustaqim Kusuma Sya’bana

2017-12-01

Full Text Available This is the preliminary finding of a study to simulate lumbar and neck flexion while ingress to the paratransit. The result of simulation will determine design aspect criteria as a preliminary step before ideation and implementation design steps. Biomechanics of Bodies (BoB is software that used to represent passenger task during paratransit ingress simulation, with skeleton model that used is height 165 cm and weight 65 kg. Environment to represent this simulation is measured Suzuki Carry SS 2013 as a private car that has been modified into a public transportation in accordance with the Indonesian government road-worthy test. Due to the low height of the entrance and the high ground clearance, lumbar and neck joint angle was a focus of this ingress simulation. The peak angle at the neck joint is 40° when 2 s skeleton nod in the door limitation ingress and lumbar flexion is 70° when 5 s skeleton is walking while bend over that will increase the load on that area. Based on biomechanical simulation approach, we may suggest the dimension of public transportation design framework developments, especially paratransit.

Design and testing of a rotational brake with shear thickening fluids

Science.gov (United States)

Tian, Tongfei; Nakano, Masami

2017-03-01

A rotational brake working with shear thickening fluid (STF) was designed and tested in this study. With the optimisation in design, most of the STF in the brake can receive the same shear rate when the brake rotates. The parts of this brake were fabricated with a 3D printer and then assembled manually. Three types of STFs with various carrier fluids and different particles were fabricated and tested with a rheometer. Then the brake with each STF was separately tested with the rheometer. The estimated and measured torques as a function of the angular velocity fit each other well. The stability of the rotational STF brake was investigated in repeated tests, which proved the function of the brake for a long time.

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion

NARCIS (Netherlands)

Kerkum, Yvette L.; Buizer, Annemieke I.; van den Noort, Josien C.; Becher, Jules G.; Harlaar, Jaap; Brehm, Merel-Anne

2015-01-01

Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion

NARCIS (Netherlands)

Kerkum, Y.L.; Buizer, A.I.; van den Noort, J.C.; Becher, J.G.; Harlaar, J.; Brehm, M.A.

2015-01-01

Introduction: Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off

Rotational and translational Brownian motion

International Nuclear Information System (INIS)

Coffey, W.T.; Salford Univ.

1980-01-01

In this review it is proposed to summarise the work on the theory of the translational and rotational Brownian movement which has been carried on over roughly the past 30 years. The review is intended to take the form of a tutorial paper rather than a list of the results obtained by the various investigators over the period in question. In this vein then it seems appropriate to firstly give a brief account of those parts of the theory of probability which are relevant to the problems under discussion. (orig.)

Does Semi-Rigid Instrumentation Using Both Flexion and Extension Dampening Spacers Truly Provide an Intermediate Level of Stabilization?

Directory of Open Access Journals (Sweden)

Dilip Sengupta

2013-01-01

Full Text Available Conventional posterior dynamic stabilization devices demonstrated a tendency towards highly rigid stabilization approximating that of titanium rods in flexion. In extension, they excessively offload the index segment, making the device as the sole load-bearing structure, with concerns of device failure. The goal of this study was to compare the kinematics and intradiscal pressure of monosegmental stabilization utilizing a new device that incorporates both a flexion and extension dampening spacer to that of rigid internal fixation and a conventional posterior dynamic stabilization device. The hypothesis was the new device would minimize the overloading of adjacent levels compared to rigid and conventional devices which can only bend but not stretch. The biomechanics were compared following injury in a human cadaveric lumbosacral spine under simulated physiological loading conditions. The stabilization with the new posterior dynamic stabilization device significantly reduced motion uniformly in all loading directions, but less so than rigid fixation. The evaluation of adjacent level motion and pressure showed some benefit of the new device when compared to rigid fixation. Posterior dynamic stabilization designs which both bend and stretch showed improved kinematic and load-sharing properties when compared to rigid fixation and when indirectly compared to existing conventional devices without a bumper.

The effect of halo-vest length on stability of the cervical spine. A study in normal subjects.

Science.gov (United States)

Wang, G J; Moskal, J T; Albert, T; Pritts, C; Schuch, C M; Stamp, W G

1988-03-01

In order to study how the efficiency of the halo vest is affected by different lengths of the vest, an experimental headband was devised that allowed the head of a normal person to be held securely in the halo attachment. The vest was then modified to allow it to be adjusted to three different lengths (Fig. 2): a full vest extended to the iliac crests, a short vest extended to the twelfth ribs, and a half vest extended to the level of the nipples. Twenty normal, healthy adult men participated in the study. For each vest length, radiographs were made of each subject demonstrating rotation, flexion-extension, and lateral bending of the cervical spine. There was no rotation of the cervical spine, regardless of the length of the vest. There was a variable degree of motion in flexion or extension of the upper part of the cervical spine with all vest lengths, but this was not statistically significant. There was definite increase of motion caudad to the level of the fifth cervical vertebra regardless of the length of the vest. We concluded that a lesion of the upper part of the cervical spine can be treated effectively by halo traction with a half vest. This will improve the comfort and care of the patient and avoid the necessity of removing the vest if emergency cardiovascular resuscitation is needed. In the treatment of lesions of the lower part of the cervical spine (caudad to the level of the fourth cervical vertebra), the use of a halo vest that extends caudad to the level of the twelfth ribs does provide additional stability.

Tertiary block rotations in the Fars Arc (Zagros, Iran)

Science.gov (United States)

Aubourg, C.; Smith, B.; Bakhtari, H. R.; Guya, N.; Eshraghi, A.

2008-05-01

The Fars arc accommodates the oblique convergence between the Arabic plate and the Iran block. Many geological observations suggest block rotations from regional to local scales. We present palaeomagnetic investigations in the Fars arc and its eastern termination, the Zagros-Makran syntaxis. Sixty-four sites have been sampled covering the Palaeocene Pabdeh Fm. to Mio-Pliocene Agha-Jhari Fm., the latest being the most sampled formation. We document pre-tilting components in all formations. However, coarse fractions of Agha-Jhari clastics formation retain a post-tilting remagnetization. As a whole, block rotations rarely exceed 20°. In the western Fars arc, clockwise and counter-clockwise rotations of small amplitudes are consistent with the torsions observed near the strike slip Kazerun and Mangarak faults. In the Zagros Makran syntaxis, counter-clockwise and clockwise rotations are observed, respectively, in the western and eastern part. This pattern is consistent with an amplification of the shape of the syntaxis. Between Zagros and Makran, palaeomagnetic data support that the present-day arcuate shape of the arc is secondary. We assume that most of the block rotations took place during the Plio-Pleistocene, during a blocking stage of the Zagros-Makran syntaxis. We emphasize the role of Oman Peninsula which plays as an indenter for the propagation of the Fars thrust belt.

THE CONTRACTION OF OVERLYING CORONAL LOOP AND THE ROTATING MOTION OF A SIGMOID FILAMENT DURING ITS ERUPTION

Energy Technology Data Exchange (ETDEWEB)

Yan, X. L.; Qu, Z. Q.; Xue, Z. K.; Deng, L. H.; Ma, L.; Kong, D. F. [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011 (China); Pan, G. M. [College of Mathematics Physics and Information Engineering, Jiaxing University, Jiaxing 314001 (China); Liu, J. H. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2013-06-15

We present an observation of overlying coronal loop contraction and rotating motion of the sigmoid filament during its eruption on 2012 May 22 observed by the Solar Dynamics Observatory (SDO). Our results show that the twist can be transported into the filament from the lower atmosphere to the higher atmosphere. The successive contraction of the coronal loops was due to a suddenly reduced magnetic pressure underneath the filament, which was caused by the rising of the filament. Before the sigmoid filament eruption, there was a counterclockwise flow in the photosphere at the right feet of the filament and the contraction loops and a convergence flow at the left foot of the filament. The hot and cool materials have inverse motion along the filament before the filament eruption. Moreover, two coronal loops overlying the filament first experienced brightening, expansion, and contraction successively. At the beginning of the rising and rotation of the left part of the filament, the second coronal loop exhibited rapid contraction. The top of the second coronal loop also showed counterclockwise rotation during the contraction process. After the contraction of the second loop, the left part of the filament rotated counterclockwise and expanded toward the right of NOAA AR 11485. During the filament expansion, the right part of the filament also exhibited counterclockwise rotation like a tornado.

Comparison of tibiofemoral joint space width measurements from standing CT and fixed flexion radiography.

Science.gov (United States)

Segal, Neil A; Frick, Eric; Duryea, Jeffrey; Nevitt, Michael C; Niu, Jingbo; Torner, James C; Felson, David T; Anderson, Donald D

2017-07-01

The objective of this project was to determine the relationship between medial tibiofemoral joint space width measured on fixed-flexion radiographs and the three-dimensional joint space width distribution on low-dose, standing CT (SCT) imaging. At the 84-month visit of the Multicenter Osteoarthritis Study, 20 participants were recruited. A commercial SCT scanner for the foot and ankle was modified to image knees while standing. Medial tibiofemoral joint space width was assessed on radiographs at fixed locations from 15% to 30% of compartment width using validated software and on SCT by mapping the distances between three-dimensional subchondral bone surfaces. Individual joint space width values from radiographs were compared with three-dimensional joint space width values from corresponding sagittal plane locations using paired t-tests and correlation coefficients. For the four medial-most tibiofemoral locations, radiographic joint space width values exceeded the minimal joint space width on SCT by a mean of 2.0 mm and were approximately equal to the 61st percentile value of the joint space width distribution at each respective sagittal-plane location. Correlation coefficients at these locations were 0.91-0.97 and the offsets between joint space width values from radiographs and SCT measurements were consistent. There were greater offsets and variability in the offsets between modalities closer to the tibial spine. Joint space width measurements on fixed-flexion radiographs are highly correlated with three-dimensional joint space width from SCT. In addition to avoiding bony overlap obscuring the joint, a limitation of radiographs, the current study supports a role for SCT in the evaluation of tibiofemoral OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1388-1395, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Atividade eletromiográfica no agachamento nas posições de 40º, 60º e 90º de flexão do joelho Electromyograhic activity in squatting at 40°, 60° and 90° knee flexion positions

Directory of Open Access Journals (Sweden)

Catarina de Oliveira Sousa

2007-10-01

Full Text Available O objetivo deste estudo foi comparar a atividade eletromiográfica (EMG dos músculos reto femoral, bíceps femoral, tibial anterior e sóleo no agachamento, associando a posição de tronco ereto com 2 ângulos de flexão do joelho (40° e 60° e a posição de tronco fletido a 45° com 3 ângulos de flexão do joelho (40°, 60° e 90°. Todas as combinações foram realizadas com e sem acréscimo de carga (10kg. A amostra foi composta por 12 indivíduos saudáveis com idade de 21,1 ± 2,5 anos e massa corporal de 62,8 ± 7,4kg. O EMG dos músculos citados foi registrado, isometricamente, em 10 posições de agachamento. Para a análise estatística foi aplicada ANOVA Two-Way de Friedman e o teste Post-Hoc de Newman-Keuls. Os resultados mostraram co-ativação entre os músculos reto femoral e bíceps femoral nas posições de tronco fletido e joelho em flexão de 40º e, entre os músculos reto femoral e sóleo, nas demais posições (p The aim of this study was to compare the electromyographic (EMG activity of the femoris rectus, femoris biceps, tibialis anterior and soleus muscles in squatting, associating the trunk in erect position with two angles of knee flexion (40° and 60° and the trunk at 45° flexion with three angles of knee flexion (40°, 60° and 90°. All associations were performed with and without additional load (10 kg. The sample was composed of 12 healthy individuals with mean age of 21.1 ± 2.5 years and weight of 62.8 ± 7.4 kg. The EMG of the cited muscles was isometrically registered in 10 squatting positions. For statistical analysis, Friedman Two-Way ANOVA and the Newman-Keuls Post-Hoc test were used. The results showed co-activation between the femoris rectus and femoris biceps muscles with the trunk in flexion and at 40° of knee flexion and between the femoris rectus and soleus muscles in the other positions considered (p < 0.05. It was also possible to observe co-activation between tibialis anterior and femoris

[Kinematics of the triangular fibrocartilage complex during forearm rotation in vivo].

Science.gov (United States)

Xu, Jing; Tang, Jin-bo; Jia, Zhong-zheng; Xie, Ren-guo

2009-11-01

To investigate three-dimensional kinematics of the superficial and deep portion of triangular fibrocartilage complex (TFCC) in different parts of the forearm rotation. Six wrists of 6 volunteers were used to obtain CT scans at different positions of the wrist. The wrists were scanned from 90 degrees of pronation to 90 degrees of supination at an interval of 30 degrees. The 3-dimensional radius and ulna were reconstructed with customized software and changes in length of the superficial and deep portion of TFCC during forearm rotation. In forearm pronation, the superficial dorsal portion and the deep palmar portion of the TFCC were tight. While the superficial palmar portion and the deep dorsal potion of the TFCC were lax. In supination, the changes in length of all these fibers were reverse. In forearm rotation one portion fibers of dorsal TFCC and one portion fibers of palmar TFCC are tight, and this mechanism controls stability during DRUJ rotation.

Rotationally invariant correlation filtering

International Nuclear Information System (INIS)

Schils, G.F.; Sweeney, D.W.

1985-01-01

A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

Translational and rotational dynamic analysis of a superconducting levitation system

International Nuclear Information System (INIS)

Cansiz, A; Hull, J R; Gundogdu, Oe

2005-01-01

The rotational dynamics of a disc-shaped permanent magnet rotor levitated over a high temperature superconductor was studied experimentally and theoretically. The interaction between the rotor magnet and the superconductor was modelled by assuming the magnet to be a magnetic dipole and the superconductor a diamagnet. In the magnetomechanical analysis of the superconductor part, the frozen image concept was combined with the diamagnetic image, and the damping in the system was neglected. The interaction potential of the system is the combination of magnetic and gravitational potentials. From the dynamical analysis the equations of motion of the permanent magnet were stated as a function of lateral, vertical, tilt, precision and rotating angles. The vibration behaviour and correlation of the vibration of one direction with that of another were determined with a numerical calculation based on the Runge-Kutta method. The various vibrational frequencies identified were vertical, radial, tilt, precession and rotation. The tests performed for experimental verifications were translational and rotational. The permanent magnet was 'spun up' under vacuum conditions to analyse the dynamics of the free 'spin down' behaviour of the permanent magnet

Elbow Flexion Contractures in Childhood in Obstetric Brachial Plexus Lesions: A Longitudinal Study of 20 Neurosurgically Reconstructed Infants with 8-Year Follow-up

NARCIS (Netherlands)

van der Sluijs, M.; van Ouwerkerk, W.J.R.; van der Sluijs, J.A.; van Royen, B.J.

2015-01-01

Objective Little knowledge exists on the development of elbow flexion contractures in children with obstetrical brachial plexus lesion (OBPL). This study aims to evaluate the prognostic significance of several neuromuscular parameters in infants with OBPL regarding the later development of elbow

On some aspects of the semiclassical approach to giant resonances of rotating nuclei

International Nuclear Information System (INIS)

Winter, J.

1985-01-01

Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. - The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. - In its generalization from constant angular velocity to constant angular momentum, our model is used to demonstrate that cranking calculations of rotating giant resonances should be corrected for an oscillation of the cranking parameter to assure angular-momentum conservation. (orig.)

Effect of slow, small movement on the vibration-evoked kinesthetic illusion.

Science.gov (United States)

Cordo, P J; Gurfinkel, V S; Brumagne, S; Flores-Vieira, C

2005-12-01

The study reported in this paper investigated how vibration-evoked illusions of joint rotation are influenced by slow (0.3 degrees /s), small (2-4 degrees ) passive rotation of the joint. Normal human adults (n=15) matched the perceived position of the left ("reference") arm with the right ("matching") arm while vibration (50 pps, 0.5 mm) was applied for 30 s to the relaxed triceps brachii of the reference arm. Both arms were constrained to rotate horizontally at the elbow. Three experimental conditions were investigated: (1) vibration of the stationary reference arm, (2) slow, small passive extension or flexion of the reference arm during vibration, and (3) slow, small passive extension or flexion of the reference arm without vibration. Triceps brachii vibration at 50 pps induced an illusion of elbow flexion. The movement illusion began after several seconds, relatively fast to begin with and gradually slowing down to a stop. On average, triceps vibration produced illusory motion at an average latency of 6.3 s, amplitude of 9.7 degrees , velocity of 0.6 degrees /s, and duration of 16.4 s. During vibration, slow, small ( approximately 0.3 degrees /s, 1.3 degrees ) passive rotations of the joint dramatically enhanced, stopped, or reversed the direction of illusory movement, depending on the direction of the passive joint rotation. However, the subjects' perceptions of these passive elbow rotations were exaggerated: 2-3 times the size of the actual movement. In the absence of vibration, the subjects accurately reproduced these passive joint rotations. We discuss whether the exaggerated perception of slow, small movement during vibration is better explained by contributions of non muscle spindle Ia afferents or by changes in the mechanical transmission of vibration to the receptor.

Impaired growth of denervated muscle contributes to contracture formation following neonatal brachial plexus injury.

Science.gov (United States)

Nikolaou, Sia; Peterson, Elizabeth; Kim, Annie; Wylie, Christopher; Cornwall, Roger

2011-03-02

The etiology of shoulder and elbow contractures following neonatal brachial plexus injury is incompletely understood. With use of a mouse model, the current study tests the novel hypothesis that reduced growth of denervated muscle contributes to contractures following neonatal brachial plexus injury. Unilateral brachial plexus injuries were created in neonatal mice by supraclavicular C5-C6 nerve root excision. Shoulder and elbow range of motion was measured four weeks after injury. Fibrosis, cross-sectional area, and functional length of the biceps, brachialis, and subscapularis muscles were measured over four weeks following injury. Muscle satellite cells were cultured from denervated and control biceps muscles to assess myogenic capability. In a comparison group, shoulder motion and subscapularis length were assessed following surgical excision of external rotator muscles. Shoulder internal rotation and elbow flexion contractures developed on the involved side within four weeks following brachial plexus injury. Excision of the biceps and brachialis muscles relieved the elbow flexion contractures. The biceps muscles were histologically fibrotic, whereas fatty infiltration predominated in the brachialis and rotator cuff muscles. The biceps and brachialis muscles displayed reduced cross-sectional and longitudinal growth compared with the contralateral muscles. The upper subscapularis muscle similarly displayed reduced longitudinal growth, with the subscapularis shortening correlating with internal rotation contracture. However, excision of the external rotators without brachial plexus injury caused no contractures or subscapularis shortening. Myogenically capable satellite cells were present in denervated biceps muscles despite impaired muscle growth in vivo. Injury of the upper trunk of the brachial plexus leads to impaired growth of the biceps and brachialis muscles, which are responsible for elbow flexion contractures, and impaired growth of the subscapularis

Surface-micromachined rotatable member having a low-contact-area hub

Science.gov (United States)

Rodgers, M. Steven; Sniegowski, Jeffry J.; Krygowski, Thomas W.

2003-11-18

A surface-micromachined rotatable member formed on a substrate and a method for manufacturing thereof are disclosed. The surface-micromachined rotatable member, which can be a gear or a rotary stage, has a central hub, and an annulus connected to the central hub by an overarching bridge. The hub includes a stationary axle support attached to the substrate and surrounding an axle. The axle is retained within the axle support with an air-gap spacing therebetween of generally 0.3 .mu.m or less. The rotatable member can be formed by alternately depositing and patterning layers of a semiconductor (e.g. polysilicon or a silicon-germanium alloy) and a sacrificial material and then removing the sacrificial material, at least in part. The present invention has applications for forming micromechanical or microelectromechanical devices requiring lower actuation forces, and providing improved reliability.

Surface--micromachined rotatable member having a low-contact-area hub

Science.gov (United States)

Rodgers, M. Steven; Sniegowski, Jeffry J.

2002-01-01

A surface-micromachined rotatable member formed on a substrate and a method for manufacturing thereof are disclosed. The surface-micromachined rotatable member, which can be a gear or a rotary stage, has a central hub, and an annulus connected to the central hub by an overarching bridge. The hub includes a stationary axle support attached to the substrate and surrounding an axle. The axle is retained within the axle support with an air-gap spacing therebetween of generally 0.3 .mu.m or less. The rotatable member can be formed by alternately depositing and patterning layers of a semiconductor (e.g. polysilicon or a silicon-germanium alloy) and a sacrificial material and then removing the sacrificial material, at least in part. The present invention has applications for forming micromechanical or microelectromechanical devices requiring lower actuation forces, and providing improved reliability.

Nanoparticles in dilute solution : A numerical study of rotational diffusion

Energy Technology Data Exchange (ETDEWEB)

Evensen, Tom Richard

2008-06-15

This thesis is dedicated to Brownian dynamics simulations of rotational diffusion. A rotation dynamics engine has been implemented and tested. This engine will in the future be integrated as a part of a complete Brownian dynamics simulation tool. The special case, when translational motion can be ignored, has thoroughly been studied. Two choices of generalized coordinates describing angular orientation of the particles are used. The Euler angles, which constitute the classical choice, and the Cartesian components of the rotation vector, which was recently introduced as an alternative, are being compared with regards to computational efficiency. Results from both equilibrium and non-equilibrium simulations are presented. The consistency of two new algorithms is demonstrated on systems of free rigid particles with arbitrary surface topographies. The algorithms make use of only the principal values of the rotational mobility tensor, assuming the corresponding principal axes coincide with the body-fixed coordinate system. These three scalars contain all information about the particle surface topography relevant for rotational diffusion. The calculation of the mobility tensor can be performed in a pre-calculation step, which makes the algorithm itself highly efficient. Both choices of generalized coordinates correctly reproduce theoretical predictions, but we have found that the algorithm using the Cartesian components of the rotation vector as generalized coordinates outperform its counterpart using the Euler angles by up to a factor 1000 in extreme cases. The reason for this improvement is that the algorithm using the Cartesian components of the rotation vector is free of singularities. (Author). refs. figs

Streaming potential near a rotating porous disk.

Science.gov (United States)

Prieve, Dennis C; Sides, Paul J

2014-09-23

Theory and experimental results for the streaming potential measured in the vicinity of a rotating porous disk-shaped sample are described. Rotation of the sample on its axis draws liquid into its face and casts it from the periphery. Advection within the sample engenders streaming current and streaming potential that are proportional to the zeta potential and the disk's major dimensions. When Darcy's law applies, the streaming potential is proportional to the square of the rotation at low rate but becomes invariant with rotation at high rate. The streaming potential is invariant with the sample's permeability at low rate and is proportional to the inverse square of the permeability at high rate. These predictions were tested by determining the zeta potential and permeability of the loop side of Velcro, a sample otherwise difficult to characterize; reasonable values of -56 mV for zeta and 8.7 × 10(-9) m(2) for the permeability were obtained. This approach offers the ability to determine both the zeta potential and the permeability of materials having open structures. Compressing them into a porous plug is unnecessary. As part of the development of the theory, a convenient formula for a flow-weighted volume-averaged space-charge density of the porous medium, -εζ/k, was obtained, where ε is the permittivity, ζ is the zeta potential, and k is the Darcy permeability. The formula is correct when Smoluchowski's equation and Darcy's law are both valid.

Nuclear collective rotation in the SU3 model, 2

International Nuclear Information System (INIS)

Kinouchi, Shin-ichi; Kishimoto, Teruo; Kammuri, Tetsuo.

1989-05-01

The collective rotation of a nuclear system with the SU 3 Hamiltonian is described by the quantal dynamical nuclear field theory. An angular frequency in the Coriolis interaction of the driving Hamiltonian is replaced by a total angular momentum operator divided by the corresponding moment of inertia. We consider here the low spin states for a triaxial intrinsic configuration. The rotational effect is taken into account by using the effective quadrupole and angular momentum operators, whose expressions are different depending on whether they refer to the laboratory frame or the body-fixed one. Effective forms of the total Hamiltonian and the particle angular momentum are compared with the exact SU 3 energy and the rotor's angular momentum, respectively. In order to dissolve the disagreement for the effective operators, the perturbing interaction should be supplemented by a residual part of the quadrupole-quadrupole interaction, which restores the rotational invariance of the intrinsic Hamiltonian. (author)

Center for Innovative Minimally Invasive Therapy (CIMIT)

Science.gov (United States)

2004-10-01

data. We hypothesize that a) the portable gait evaluator will provide ankle dorsi/ plantar flexion and external/internal foot rotation motion output...output from 2 sensors (pitch gyro and a bend sensor) is used to determining ankle dorsi flexion/ plantar flexion is underway. The gyroscopic data for... Fascia 34 14.9 ± 2.2 137.5 ± 14.2 Muscle 40 20.9 ± 2.5 163.7 ± 19.9 Bone 34 32.5 ± 4.2 101.3 ± 16.8 Cartilage 34 23.3 ± 3.3 127.3 ± 15.2 Dura 34 41.7

NH3 quantum rotators in Hofmann clathrates: intensity and width of rotational transition lines

International Nuclear Information System (INIS)

Vorderwisch, Peter; Sobolev, Oleg; Desmedt, Arnaud

2004-01-01

Inelastic structure factors for rotational transitions of uniaxial NH 3 quantum rotators, measured in a Hofmann clathrate with biphenyl as guest molecule, agree with those calculated for free rotators. A finite intrinsic line width, found for rotational transitions involving the rotational level j=3 at low temperature, supports a recently suggested model based on resonant rotor-rotor coupling

Rotation Frequencies of Small Jovian Trojan Asteroids: An Excess of Slow Rotators

Science.gov (United States)

French, Linda M.; Stephens, Robert D.; James, David J.; Coley, Daniel; Connour, Kyle

2015-11-01

Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half the 131 objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015).A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004).Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

Rotation curves of galaxies by fourth order gravity

International Nuclear Information System (INIS)

Stabile, A.; Scelza, G.

2011-01-01

We investigate the radial behavior of galactic rotation curves by a Fourth Order Gravity adding also the dark matter component. The Fourth Order Gravity is a theory of gravity described by Lagrangian generalizing the one of Hilbert-Einstein containing a generic function of the Ricci scalar, the Ricci and Riemann tensor. A systematic analysis of rotation curves, in the Newtonian Limit of theory, induced by all galactic substructures of ordinary matter is shown. This analysis is presented for Fourth Order Gravity with and without dark matter. The outcomes are compared with respect to the classical outcomes of General Relativity. The gravitational potential of pointlike mass is the usual potential corrected by two Yukawa terms. The rotation curve is higher or also lower than curve of General Relativity if in the Lagrangian the Ricci scalar square is dominant or not with respect to the contribution of the Ricci tensor square. The theoretical spatial behaviors of rotation curve are compared with the experimental data for the Milky Way and the galaxy NGC 3198. Although the Fourth Order Gravity gives more rotational contributions, in the limit of large distances the Keplerian behavior is ever present, and it is missing only if we add the dark matter component. However by modifying the theory of gravity, consequently, also the spatial description of dark matter could undergo a modification and the free parameters of model can assume different values. After an analytical discussion of theoretical behaviors and the comparing with experimental evidence we can claim that any Fourth Order Gravity is not successful to explain the galactic rotation curves. In the last part of paper we analyze the gravitational potential induced by Lagrangian containing only powers of Ricci scalar. In this case we find an inconsistency in the boundary conditions in the passage from matter to the vacuum.

Sacroiliac Joint Fusion Minimally Affects Adjacent Lumbar Segment Motion: A Finite Element Study.

Science.gov (United States)

Lindsey, Derek P; Kiapour, Ali; Yerby, Scott A; Goel, Vijay K

2015-01-01

Adjacent segment disease is a recognized consequence of fusion in the spinal column. Fusion of the sacroiliac joint is an effective method of pain reduction. Although effective, the consequences of sacroiliac joint fusion and the potential for adjacent segment disease for the adjacent lumbar spinal levels is unknown. The objective of this study was to quantify the change in range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments due to sacroiliac joint fusion and compare these changes to previous literature to assess the potential for adjacent segment disease in the lumbar spine. An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the sacroiliac joint using three laterally placed triangular implants (iFuse Implant System, SI-BONE, Inc., San Jose, CA). The range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments were calculated using a hybrid loading protocol and compared with the intact range of motion in flexion, extension, lateral bending, and axial rotation. The range of motions of the treated sacroiliac joints were reduced in flexion, extension, lateral bending, and axial rotation, by 56.6%, 59.5%, 27.8%, and 53.3%, respectively when compared with the intact condition. The stiffening of the sacroiliac joint resulted in increases at the adjacent lumbar motion segment (L5-S1) for flexion, extension, lateral bending, and axial rotation, of 3.0%, 3.7%, 1.1%, and 4.6%, respectively. Fusion of the sacroiliac joint resulted in substantial (> 50%) reductions in flexion, extension, and axial rotation of the sacroiliac joint with minimal (sacroiliac joint fusion, the long-term clinical results remain to be investigated.

Trunk and hip biomechanics influence anterior cruciate loading mechanisms in physically active participants.

Science.gov (United States)

Frank, Barnett; Bell, David R; Norcross, Marc F; Blackburn, J Troy; Goerger, Benjamin M; Padua, Darin A

2013-11-01

Excessive trunk motion and deficits in neuromuscular control (NMC) of the lumbopelvic hip complex are risk factors for anterior cruciate ligament (ACL) injury. However, the relationship between trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads during a sidestep cutting task has not been examined. To determine if there is an association between multiplanar trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads with ACL injury during a sidestep cutting task. Descriptive laboratory study. The hip and knee biomechanics and trunk motion of 30 participants (15 male, 15 female) were analyzed during a sidestep cutting task using an optoelectric camera system interfaced to a force plate. Trunk and lower extremity biomechanics were calculated from the kinematic and ground-reaction force data during the first 50% of the stance time during the cutting task. Pearson product moment correlation coefficients were calculated between trunk and lower extremity biomechanics. Multiple linear regression analyses were carried out to determine the amount of variance in triplanar knee loading explained by trunk motion and hip moments. A greater internal knee varus moment (mean, 0.11 ± 0.12 N·m/kg*m) was associated with less transverse-plane trunk rotation away from the stance limb (mean, 20.25° ± 4.42°; r = -0.46, P = .011) and a greater internal hip adduction moment (mean, 0.33 ± 0.25 N·m/kg*m; r = 0.83, P < .05). A greater internal knee external rotation moment (mean, 0.11 ± 0.08 N·m/kg*m) was associated with a greater forward trunk flexion (mean, 7.62° ± 5.28°; r = 0.42, P = .020) and a greater hip internal rotation moment (mean, 0.15 ± 0.16 N·m/kg*m; r = 0.59, P = .001). Trunk rotation and hip adduction moment explained 81% (P < .05) of the variance in knee varus moment. Trunk flexion and hip internal rotation moment explained 48% (P < .05) of the variance in knee external rotation moment. Limited trunk rotation displacement

Operational Modal Analysis of Rotating Machinery

DEFF Research Database (Denmark)

Gres, Szymon; Andersen, Palle; Damkilde, Lars

2019-01-01

and deploys an orthogonal projection of the latter onto the raw measurements to remove the harmonic part of the signal. The new technique is a part of an semi-automated framework for OMA of structures contaminated with harmonics, whose flow is presented in this paper. The merit of the framework is discussed......Harmonic excitation of structures caused by rotating equipment is a problem faced by many engineers in the field of Operational Modal Analysis (OMA). Several methods to discard the influence of harmonic inputs over systems natural responses has been proposed in the literature and implemented...... in various software solutions. This paper recalls some of the most used techniques and uses a new time domain method for removing harmonics from measurements. Deployed method does not rely on filtering, statistical detection nor on non-linear fitting. Instead, it predicts the harmonic part of the time series...

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1977-01-01

History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

Rotations with Rodrigues' vector

International Nuclear Information System (INIS)

Pina, E

2011-01-01

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

Effect of rotation on convective mass transfer in rotating channels

International Nuclear Information System (INIS)

Pharoah, J.G.; Djilali, N.

2002-01-01

Laminar flow and mass transfer in rotating channels is investigated in the context of centrifugal membrane separation. The effect of orientation with respect to the rotational axis is examined for rectangular channels of aspect ratio 3 and the Rossby number is varied from 0.3 to 20.9. Both Ro and the channel orientation are found to have a significant effect on the flow. Mass transfer calculations corresponding to reverse osmosis desalination are carried out at various operating pressures and all rotating cases exhibit significant process enhancements at relatively low rotation rates. Finally, while it is common in the membrane literature to correlate mass transfer performance with membrane shear rates this is shown not to be valid in the cases presented herein. (author)

Features of the mass transfer in magnetic cataclysmic variables with fast-rotating white dwarfs

Directory of Open Access Journals (Sweden)

Isakova Polina

2014-01-01

Full Text Available The flow structure in magnetic cataclysmic variables was investigated taking into account the effects of strong magnetic field and fast rotation of the white dwarf. We modeled the AE Aqr system as a unique object that has the rotation period of the white dwarf is about 1000 times shorter than the orbital period of the binary system. Observations show that in spite of fast rotation of the white dwarf some part of the stream from the inner Lagrange point comes into the Roche lobe region. We analyzed possible mechanisms preventing material to outflow from the system.

[Muscular trunk stability in professional and amateur volleyball players].

Science.gov (United States)

Miltner, O; Siebert, C; Tschaepe, R; Maus, U; Kieffer, O

2010-03-01

The aim of this study was to analyse the efficiency of muscular activity in the trunk stabilisation of professional volleyball players compared to a group of amateur hobby players. The results were compared amongst the groups as well as with a reference group consisting of asymptomatic individuals. The question to be answered was whether or not professional volleyball players possess a characteristic strength profile in their trunk musculature and if differences exist with regard to the individuals' competitive playing level. In this comparative study 12 professional volleyball players (German Bundesliga) and 18 non-professional volleyball players were analysed with regard to their isometric strength profile in all three planes. The reference group was provided by the Proxomed company, which had previously analysed healthy untrained individuals (n = 1045) of various age groups. A sports-specific profile for the musculature of volleyball players revealed a significant reduction in the flexion and rotation strength as well as a well-developed lateral flexion strength (highly significant when compared to the reference group). With reference to the level played, better strength values in flexion and lateral flexion were found among the professional athletes. Professional volleyball players present with a characteristic trunk musculature strength profile. A detailed analysis of the muscle strength of the spine as part of a sports medicine work-up could prove helpful in preventing injuries and overuse problems in professional and hobby volleyball players.

Bayesian analysis of rotating machines - A statistical approach to estimate and track the fundamental frequency

DEFF Research Database (Denmark)

Pedersen, Thorkild Find

2003-01-01

frequency and the related frequencies as orders of the fundamental frequency. When analyzing rotating or reciprocating machines it is important to know the running speed. Usually this requires direct access to the rotating parts in order to mount a dedicated tachometer probe. In this thesis different......Rotating and reciprocating mechanical machines emit acoustic noise and vibrations when they operate. Typically, the noise and vibrations are concentrated in narrow frequency bands related to the running speed of the machine. The frequency of the running speed is referred to as the fundamental...

Low-Cost Rotating Experimentation in Compressor Aerodynamics Using Rapid Prototyping

Directory of Open Access Journals (Sweden)

Mathias Michaud

2016-01-01

Full Text Available With the rapid evolution of additive manufacturing, 3D printed parts are no longer limited to display purposes but can also be used in structural applications. The objective of this paper is to show that 3D prototyping can be used to produce low-cost rotating turbomachinery rigs capable of carrying out detailed flow measurements that can be used, among other things, for computational fluid dynamics (CFD code validation. A fully instrumented polymer two-stage axial-mixed flow compressor test rig was designed and fabricated with stereolithography (SLA technology by a team of undergraduate students as part of a senior-year design course. Experiments were subsequently performed on this rig to obtain both the overall pressure rise characteristics of the compressor and the stagnation pressure distributions downstream of the blade rows for comparison with CFD simulations. In doing so, this work provides a first-of-a-kind assessment of the use of polymer additive technology for low-cost rotating turbomachinery experimentation with detailed measurements.

Observations of rotation in JET plasmas with electron heating by ion cyclotron resonance heating

DEFF Research Database (Denmark)

Hellsten, T.; Johnson, T. J.; Van Eester, D.

2012-01-01

The rotation of L-mode plasmas in the JET tokamak heated by waves in the ion cyclotron range of frequencies (ICRF) damped on electrons, is reported. The plasma in the core is found to rotate in the counter-current direction with a high shear and in the outer part of the plasma with an almost......, electron absorption of the fast magnetosonic wave by transit time magnetic pumping and electron Landau damping (TTMP/ELD) is the dominating absorption mechanism. Inverted mode conversion is done in (He-3)-H plasmas where the mode converted waves are essentially absorbed by electron Landau damping. Similar...... rotation profiles are seen when heating at the second harmonic cyclotron frequency of He-3 and with mode conversion at high concentrations of He-3. The magnitude of the counter-rotation is found to decrease with an increasing plasma current. The correlation of the rotation with the electron temperature...

THE RADIO ACTIVITY-ROTATION RELATION OF ULTRACOOL DWARFS

International Nuclear Information System (INIS)

McLean, M.; Berger, E.; Reiners, A.

2012-01-01

We present a new radio survey of about 100 late-M and L dwarfs undertaken with the Very Large Array. The sample was chosen to explore the role of rotation in the radio activity of ultracool dwarfs. As part of the survey we discovered radio emission from three new objects, 2MASS J 0518113 – 310153 (M6.5), 2MASS J 0952219 – 192431 (M7), and 2MASS J 1314203 + 132001 (M7), and made an additional detection of LP 349-25 (M8). Combining the new sample with results from our previous studies and from the literature, we compile the largest sample to date of ultracool dwarfs with radio observations and measured rotation velocities (167 objects). In the spectral type range M0-M6 we find a radio activity-rotation relation, with saturation at L rad /L bol ≈ 10 –7.5 above vsin i ≈ 5 km s –1 , similar to the relation in Hα and X-rays. However, at spectral types ∼> M7 the ratio of radio to bolometric luminosity increases significantly regardless of rotation velocity, and the scatter in radio luminosity increases. In particular, while the most rapid rotators (vsin i ∼> 20 km s –1 ) exhibit 'super-saturation' in X-rays and Hα, this effect is not seen in the radio. We also find that ultracool dwarfs with vsin i ∼> 20 km s –1 have a higher radio detection fraction by about a factor of three compared to objects with vsin i ∼ –1 . When measured in terms of the Rossby number (Ro), the radio activity-rotation relation follows a single trend and with no apparent saturation from G to L dwarfs and down to Ro ∼ 10 –3 ; in X-rays and Hα there is clear saturation at Ro ∼ rad /R 2 * ) as a function of Ro. The continued role of rotation in the overall level of radio activity and in the fraction of active sources, and the single trend of L rad /L bol and L rad /R 2 * as a function of Ro from G to L dwarfs, indicates that rotation effects are important in regulating the topology or strength of magnetic fields in at least some fully convective dwarfs. The fact that

Rotated alphanumeric characters do not automatically activate frontoparietal areas subserving mental rotation

DEFF Research Database (Denmark)

Weiss, Michael M; Wolbers, Thomas; Peller, Martin

2008-01-01

Functional neuroimaging studies have identified a set of areas in the intraparietal sulcus and dorsal precentral cortex which show a linear increase in activity with the angle of rotation across a variety of mental rotation tasks. This linear increase in activity with angular disparity suggests t...... modulated by angular disparity during the stimulus categorization task. These results suggest that at least for alphanumerical characters, areas implicated in mental rotation will only be called into action if the task requires a rotational transformation....

Rotating dryer

International Nuclear Information System (INIS)

Noe, C.

1984-01-01

Products to dry are introduced inside a rotating tube placed in an oven, the cross section of the tube is an arc of spiral. During clockwise rotation of the tube products are maintained inside and mixed, during anticlockwise products are removed. Application is made to drying of radioactive wastes [fr

Rotating Wavepackets

Science.gov (United States)

Lekner, John

2008-01-01

Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

A biomechanical comparison of the Rogers interspinous and the Lovely-Carl tension band wiring techniques for fixation of the cervical spine.

Science.gov (United States)

Brasil, A V; Coehlo, D G; Filho, T E; Braga, F M

2000-07-01

The authors conducted a biomechanical study in which they compared the uses of the Rogers interspinous and the Lovely-Carl tension band wiring techniques for internal fixation of the cervical spine. An extensive biomechanical evaluation (stiffness in positive and negative rotations around the x, y, and z axes; range of motion in flexion-extension, bilateral axial rotation, and bilateral bending; and neutral zone in flexion-extension, bilateral axial rotation, and lateral bending to the right and to the left) was performed in two groups of intact calf cervical spines. After these initial tests, all specimens were subjected to a distractive flexion Stage 3 ligamentous lesion. Group 1 specimens then underwent surgical fixation by the Rogers technique, and Group 2 specimens underwent surgery by using the Lovely-Carl technique. After fixation, specimens were again submitted to the same biomechanical evaluation. The percentage increase or decrease between the pre- and postoperative parameters was calculated. These values were considered quantitative indicators of the efficacy of the techniques, and the efficacy of the two techniques was compared. Analysis of the findings demonstrated that in the spines treated with the Lovely-Carl technique less restriction of movement was produced without affecting stiffness, compared with those treated with the Rogers technique, thus making the Lovely-Carl technique clinically less useful.

[Mobility of a polyethylene tibial insert in a mobile total knee prosthesis].

Science.gov (United States)

Castel, E; Roger, B; Camproux, A; Saillant, G

1999-03-01

We have studied the mobility of a mobile tibial implant in total knee arthroplasty (TKA) by a radiographical evaluation. We analyzed mobility of the polyethylene tibial insert of 15 "G2S" TKA implanted for one year or more. We established a dynamic radiographical evaluation. We used 3 weight-bearing radiographs: AP in extension and two lateral (one in extension and one at 90 degrees of flexion), two AP with femoral internal and external rotation, 2 strict lateral X-rays in neutral rotation in antero-posterior replacement with a 25 kilograms strength Telos, and 2 AP in varus and valgus with Telos. Wilcoxon's test and Fisher's exact test were used for statistical evaluation. Our study demonstrated preservation of the polyethylene mobility in tibial TKA implant in all movements: in rotation, in antero-posterior translation with Telos, and even in antero-posterior translation during physiological condition with flexion-extension weight-bearing radiographs. Statistical tests were very significant. We noticed that flexion induced anterior translation of tibial polyethylene when PCL was preserved. This study answered to our question whether mobility of TKA tibial implant persists after implantation. This mobility should reduce loosening forces to the tibia and stress in the polyethylene component. Now we have to determine the amplitude of mobility required to reach this objective.

Muscle atrophy as a consequence of rotator cuff tears: should we compare the muscles of the rotator cuff with those of the deltoid?

Energy Technology Data Exchange (ETDEWEB)

Ashry, Reem; Schweitzer, Mark E.; Cunningham, Patricia; Cohen, Jodi; Babb, James; Cantos, Andrew [Hospital for Joint Diseases, NYU Medical Center, Department of Radiology, New York, NY (United States)

2007-09-15

The quantitative assessment of muscle atrophy has a degree of importance in prognosticating rotator cuff treatment. However, it has been conjectured that muscle fat increases with aging. Therefore, we thought that the quantitative assessment of the supraspinatous would be better if made in comparison with a standard of reference such as the deltoid. Consequently, we performed a two-part study, first evaluating supraspinatous changes compared with the deltoid in ''normals'' with aging, and second, determining if in patients with cuff tears the supraspinatous fat exceeds that of the deltoid. In part 1, we studied 50 patients stratified by decade. In the first sitting, two blinded independent observers quantitatively graded the deltoid (with the supraspinatous obscured) and in the second sitting the same two observers quantitatively graded the supraspinatous (with the deltoid obscured). In part 2 of the study, we evaluated patients with moderate rotator cuff tears (>2 cm) and performed the same blinded, two-sitting, quantitative assessment (with the comparison muscle obscured). We found that muscle atrophy increases with age in patients without tears (0.011/0.028 U/year), although to a greater degree in the deltoid (p = 0.032). Also, in similarly aged patients, quantitative scores of the deltoid closely matched those of the supraspinatous (p = 0.071). Notably, however, in patients with large tears, the supraspinatous showed significant changes disproportionate to those of the deltoid, regardless of patient age (p = 0.044). In the presence of a normal rotator cuff, fatty infiltration increases with age. Age-related changes occur more frequently in the deltoid, verifying this muscle's potential as a standard of reference. With cuff tears, supraspinatous atrophy was disproportionate to that of the deltoid. Therefore, systematic assessment of supraspinatous muscle atrophy may be more reliable using the deltoid as a control for comparison than

Muscle atrophy as a consequence of rotator cuff tears: should we compare the muscles of the rotator cuff with those of the deltoid?

International Nuclear Information System (INIS)

Ashry, Reem; Schweitzer, Mark E.; Cunningham, Patricia; Cohen, Jodi; Babb, James; Cantos, Andrew

2007-01-01

The quantitative assessment of muscle atrophy has a degree of importance in prognosticating rotator cuff treatment. However, it has been conjectured that muscle fat increases with aging. Therefore, we thought that the quantitative assessment of the supraspinatous would be better if made in comparison with a standard of reference such as the deltoid. Consequently, we performed a two-part study, first evaluating supraspinatous changes compared with the deltoid in ''normals'' with aging, and second, determining if in patients with cuff tears the supraspinatous fat exceeds that of the deltoid. In part 1, we studied 50 patients stratified by decade. In the first sitting, two blinded independent observers quantitatively graded the deltoid (with the supraspinatous obscured) and in the second sitting the same two observers quantitatively graded the supraspinatous (with the deltoid obscured). In part 2 of the study, we evaluated patients with moderate rotator cuff tears (>2 cm) and performed the same blinded, two-sitting, quantitative assessment (with the comparison muscle obscured). We found that muscle atrophy increases with age in patients without tears (0.011/0.028 U/year), although to a greater degree in the deltoid (p 0.032). Also, in similarly aged patients, quantitative scores of the deltoid closely matched those of the supraspinatous (p = 0.071). Notably, however, in patients with large tears, the supraspinatous showed significant changes disproportionate to those of the deltoid, regardless of patient age (p = 0.044). In the presence of a normal rotator cuff, fatty infiltration increases with age. Age-related changes occur more frequently in the deltoid, verifying this muscle's potential as a standard of reference. With cuff tears, supraspinatous atrophy was disproportionate to that of the deltoid. Therefore, systematic assessment of supraspinatous muscle atrophy may be more reliable using the deltoid as a control for comparison than assessing it in isolation

Rotator cuff - self-care

Science.gov (United States)

... this page: //medlineplus.gov/ency/patientinstructions/000358.htm Rotator cuff - self-care To use the sharing features on ... and shoulder exercises may help ease your symptoms. Rotator Cuff Problems Common rotator cuff problems include: Tendinitis , which ...

Rotational structure of the five lowest frequency fundamental vibrational states of dimethylsulfoxide

Science.gov (United States)

Cuisset, Arnaud; Drumel, Marie-Aline Martin; Hindle, Francis; Mouret, Gaël; Sadovskií, Dmitrií A.

2013-10-01

We report on the successful extended analysis of the high-frequency (200-700 GHz) part of the gas phase (sub)mm-wave spectra of dimethylsulfoxide (DMSO). The spectrum was recorded at 100 kHz resolution using a solid state subTHz spectrometer. The five lowest energy fundamental vibrational states of DMSO with frequencies below 400 cm-1 were observed as sidebands along with the main 0←0 band. Neglecting the internal rotation of methyls, our rotational Hamiltonian reproduced the spectrum to the subMHz accuracy. We have found that the asymmetric bending state ν23 is the only low frequency fundamental vibrational state with the "anomalous" rotational structure uncovered in Cuisset et al. [1]. dmsomw 2013-09-04 15:03

Examining cotton in rotation with rice and cotton in rotation with other crops using natural experiment

Science.gov (United States)

Sun, Ling; Zhu, Zesheng

2017-08-01

This paper is to show the ability of remote sensing image analysis combined with statistical analysis to characterize the environmental risk assessment of cotton in rotation with rice and cotton in rotation with other crops in two ways: (1) description of rotation period of cotton in rotation with rice and cotton in rotation with other crops by the observational study or natural experiment; (2) analysis of rotation period calculation of cotton in rotation with rice and cotton in rotation with other crops. Natural experimental results show that this new method is very promising for determining crop rotation period for estimating regional averages of environmental risk. When it is applied to determining crop rotation period, two requested remote sensing images of regional crop are required at least.

Influence of fear of falling on anticipatory postural control of medio-lateral stability during rapid leg flexion.

Science.gov (United States)

Yiou, E; Deroche, T; Do, M C; Woodman, T

2011-04-01

During leg flexion from erect posture, postural stability is organized in advance during "anticipatory postural adjustments" (APA). During these APA, inertial forces are generated that propel the centre of gravity (CoG) laterally towards stance leg side. This study examined how fear of falling (FoF) may influence this anticipatory postural control of medio-lateral (ML) stability. Ten young healthy participants performed a series of leg flexions at maximal velocity from low and high surface heights (6 and 66 cm above ground, respectively). In this latter condition with increased FoF, stance foot was placed at the lateral edge of the support surface to induce maximal postural threat. Results showed that the amplitude of ML inertial forces generated during APA decreased with FoF; this decrease was compensated by an increase in APA duration so that the CoG position at time of swing foot-off was located further towards stance leg side. With these changes in ML APA, the CoG was propelled in the same final (unipodal) position above stance foot as in condition with low FoF. These results contrast with those obtained in the literature during quiet standing which showed that FoF did not have any influence on the ML component of postural control. It is proposed that ML APA are modified with increased FoF, in such a way that the risk of a sideway fall induced by the large CoG motion is attenuated.

Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades

Science.gov (United States)

Howard, Samuel A.; Hammer, Jeremiah T.; Carney, Kelly S.; Pereira, J. Michael

2013-01-01

Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990 to 2007 in the US alone (Ref. 1). As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a nonrotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests. NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the prestress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in

Earth's variable rotation

Science.gov (United States)

Hide, Raymond; Dickey, Jean O.

1991-01-01

Recent improvements in geodetic data and practical meteorology have advanced research on fluctuations in the earth's rotation. The interpretation of these fluctuations is inextricably linked with studies of the dynamics of the earth-moon system and dynamical processes in the liquid metallic core of the earth (where the geomagnetic field originates), other parts of the earth's interior, and the hydrosphere and atmosphere. Fluctuations in the length of the day occurring on decadal time scales have implications for the topographay of the core-mantle boundary and the electrical, magnetic, ande other properties of the core and lower mantle. Investigations of more rapid fluctuations bear on meteorological studies of interannual, seasonal, and intraseasonal variations in the general circulation of the atmosphere and the response of the oceans to such variations.

The effect of ball impact location on racket and forearm joint angle changes for one-handed tennis backhand groundstrokes.

Science.gov (United States)

King, Mark; Hau, Agnes; Blenkinsop, Glen

2017-07-01

Recreational tennis players tend to have higher incidence of tennis elbow, and this has been hypothesised to be related to one-handed backhand technique and off-centre ball impacts on the racket face. This study aimed to investigate for a range of participants the effect of off-longitudinal axis and off-lateral axis ball-racket impact locations on racket and forearm joint angle changes immediately following impact in one-handed tennis backhand groundstrokes. Three-dimensional racket and wrist angular kinematic data were recorded for 14 university tennis players each performing 30 "flat" one-handed backhand groundstrokes. Off-longitudinal axis ball-racket impact locations explained over 70% of the variation in racket rotation about the longitudinal axis and wrist flexion/extension angles during the 30 ms immediately following impact. Off-lateral axis ball-racket impact locations had a less clear cut influence on racket and forearm rotations. Specifically off-longitudinal impacts below the longitudinal axis forced the wrist into flexion for all participants with there being between 11° and 32° of forced wrist flexion for an off-longitudinal axis impact that was 1 ball diameter away from the midline. This study has confirmed that off-longitudinal impacts below the longitudinal axis contribute to forced wrist flexion and eccentric stretch of the wrist extensors and there can be large differences in the amount of forced wrist flexion from individual to individual and between strokes with different impact locations.

Focal brachial enhancement deficit: a normal anatomic variant?