Uncovertebral joint injury in cervical facet dislocation: the headphones sign

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Palmieri, Francesco; Cassar-Pullicino, Victor N.; Dell' Atti, Claudia; Lalam, Radhesh K.; Tins, Bernhard J.; Tyrrell, Prudencia N.M.; McCall, Iain W. [Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Department of Radiology, Oswestry, England (United Kingdom)

2006-06-15

The purpose of our study is to demonstrate the uncovertebral mal-alignment as a reliable indirect sign of cervical facet joint dislocation. We examined the uncovertebral axial plane alignment of 12 patients with unilateral and bilateral cervical facet joint dislocation (UCFJD and BCFJD, respectively), comparing its frequency to the reverse hamburger bun sign on CT and MR axial images. Of the seven cases with BCFJD, five clearly demonstrated the diagnostic reverse facet joint hamburger bun sign on CT and MR images, but in two cases this sign was not detectable. In the five cases with UCFJD, four demonstrated the reverse hamburger bun sign on both CT and MRI. In one case the reverse hamburger bun sign was not seen adequately with either image modality, but the facet dislocation was identified on sagittal imaging. The uncovertebral mal-alignment was detected in all 12 cases. Normally, the two components of the uncovertebral joint enjoy a concentric relationship that in the axial plane is reminiscent of the relationship of headphones with the wearer's head. We name this appearance the 'headphones' sign. Radiologists should be aware of the headphones sign as a reliable indicator of facet joint dislocation on axial imaging used in the assessment of cervical spine injuries. (orig.)

Facet joint orientation and tropism in lumbar degenerative disc disease and spondylolisthesis.

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Pichaisak, Witchate; Chotiyarnwong, Chayaporn; Chotiyarnwong, Pojchong

2015-04-01

Although degenerative disc disease (DDD) and degenerative spondylolisthesis (DS) are two common causes of back pain in elderly, the association between the lumbarfacet joint angle and tropism in these conditions are still unclear. To evaluate the difference in facet joint angles between normal population and lumbar degenerative disc disease and spondylolisthesis patient. The angle of lumbar facet joints were retrospectively measured with magnetic resonance imaging (MRI) to determine whether there was a difference between degenerative diseases. MRI of patients with DDD, DS, and control group at facet joint between L3-4, L4-5 and L5-S1 level were measured in axial view (60 subjects in each group). There was no difference infacetjoint angle in DDD (44.1 ± 11.9) and control (45.6 ± 8.9), but differed in DS (40.1 ± 10. 7) and control group (p = 0.010) at L4-5 level. Facet tropism showed difference between degenerative groups and control group at L4-5 level. DS group showed difference in facet joints angle and tropism when compared with control population, while DDD showed difference only in facet tropism. In addition, longitudinal studies are needed to understand the clinical significant between facet joint angle and tropism in spinal degenerative diseases.

Treatment of lumbar facet joint syndrome by CT-guided intraarticular infiltration of fact joints

International Nuclear Information System (INIS)

Schleifer, J.; Fenzl, G.; Wolf, A.; Diehl, K.

1994-01-01

In 62 patients with facet syndrome a total of 205 joints were infiltrated, CT monitoring being used in all cases. Each facet joint was infiltrated with 0.3 ml bupivacaine and 0.8 ml methylprednisolone. The patients were divided into three groups. Group 1 consisted of 24 persons who had undergone lumbar disc surgery, group 2 of 23 patients with spondylarthrosis of the facet joints, and group 3 of 15 patients who had undergone lumbar disc surgery but hat additional spondylarthrosis. Very good results were defined as pain relief for longer than 4 weeks, good results as pain relief for up to 4 weeks and poor results as brief pain relief or none at all. In 27 patients facet infiltration was performed for the purpose of diagnosis. Results were significantly in group 2 than in group 1. In group 3 results were better than in group 1, but worse than in group 2. These differences were not statistical by significant. Seven patients in the diagnostic group had no pain relief, and facet syndrome was excluded. (orig.) [de

Degenerative Changes of the Facet Joints in Adults With Lumbar Spondylolysis.

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Goda, Yuichiro; Sakai, Toshinori; Harada, Taihei; Takao, Shoichiro; Takata, Yoichiro; Higashino, Kosaku; Harada, Masafumi; Sairyo, Koichi

2017-07-01

Radiologic analysis using computed tomography. To analyze the degenerative changes of the facet joints in patients with spondylolysis in comparison with control subjects. Defects of the pars interarticularis are thought to result in a reduction of biomechanical stress on adjacent facet joints. Therefore, degenerative changes of the facet joints in patients with spondylolysis are expected to be less than those in patients without spondylolysis. Abdominal and pelvic multidetector computed tomography scans of 2000 subjects, performed for conditions unrelated to low back pain, were reviewed. A total of 107 patients (37 women and 70 men) with L5 spondylolysis were identified [spondylolysis (+) group]. Sex-matched and age-matched controls without spondylolysis were chosen randomly [spondylolysis (-) group]. Subjects in the spondylolysis group were subdivided into either bilateral spondylolysis or unilateral spondylolysis groups for comparison with the control group. Four radiologic findings (narrowing, sclerosis, osteophyte, and bone cyst) indicative of degenerative change of the facet joints adjacent to the L5 pars defects were evaluated and the degree of degenerative change was graded by summing the number of degenerative changes (score range, 0-4). The χ test and Mann-Whitney U test were used for statistical analysis. Significantly more degenerative changes in both L4/L5 and L5/S facet joints were found in the spondylolysis (+) group than in the spondylolysis (-) group (χ test, P spondylolysis (+) group than in the spondylolysis (-) group. Degenerative changes of the facet joints at both L4/L5 and L5/S were more severe in the unilateral spondylolysis (+) group than in the spondylolysis (-) group. Degenerative changes of the facet joints in patients with lumbar spondylolysis were more severe than those without spondylolysis.

[Feasibility and accuracy of ultrasound-guided methodology in the examination of lumbar spine facet joints].

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Wen, Chuan-Bing; Li, Yong-Zhong; Tang, Qin-Qin; Sun, Lin; Xiao, Hong; Yang, Bang-Xiang; Song, Li; Liu, Hui

2013-03-01

To investigate the feasibility, accuracy of B ultrasound in the examination of joint space of lumbar spine facet joints compared with CT scan. Ten healthy adult volunteers were enrolled. The joint space of lumbar facet joints was measured by ultrasound. To identify the spinal levels, the posterior parasagittal sonograms were obtained at levels L1 to S1. The lumbar facet joints were delineated with the help of transverse sonograms at each level. Meanwhile, the lumbar facet joints were evaluated by spiral CT on the same plane, reformatted to 1-mm axial slices. A total of 88 lumbar facet joints from L1 to S1 were clearly visualized in the 10 volunteers. Both ultrasound and CT measurements showed the same average depth and lateral distance of lumbar facet joint space (P > 0.05). The lumbar facet joint space can be accurately demonstrated by ultrasound.

Facet joint injuries in acute cervical spine trauma : evaluation with CT and MRI

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Ha, Jeon Ju; Kim, Dong Hyun; Lee, Jeong Hwa; Lee, Keon; Kwon, Hyeok Po; Kwon, Jung Hyeok; Yun, Seong Mun [Dongkang General Hospital, Seoul (Korea, Republic of)

1999-05-01

To evaluate injury patterns of facet joints and associated soft tissue injuries in patients with acute traumatic cervical facet joint injuries. From among patients with cervical spine trauma, 27 with facet joint injuries, as seen on CT and MRI, were chosen for this study. CT scans were analyzed with regard to the location of facet joint injury, the presence or absence of facet dislocation or fracture, and other associated fractures. MR images were analyzed with regard to ligament injury, intervertebral disc injury, intervertebral disc herniation, and spinal cord injury. The most common location of facet joint injury was C6-7 level(n=10), followed by C5-6(n=8). Among these 27 patients with facet joint injuries, 12(44%) had bilateral injuries and 15(56%) unilateral injuries. Facet fractures were present in 17 cases(63%) and the fracture of inferior facet was more frequent than superior. Patterns of fracture were vertical, transverse, or comminuted, but vertical fracture was the most common. Various degrees of dislocation were observed in patients with facet fractures. Fractures other than facet included pillar(n=11), lamina(n=6), transverse process(n=14), body(n=13), and spinous process(n=3). On MR images, anterior longitudinal ligament injury was found in 8 patients(30%), posterior longitudinal ligament injury in 4(15%), and interspinous ligament injury in 20(74%). Twelve patients(44%) had spinal cord injuries including edema(n=8) and hemorrhage(n=4). Among patients with disc abnormalities, 11(41%) had intervertebral disc injuries, and traumatic disc herniations were found in nine. Traumatic cervical facet joint injuries were manifested as various patterns and frequently associated with other fractures or soft tissue injuries. Analysis of CT and MR findings of these injury patterns helped formulate a therapeutic plan and determine of prognosis.

Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression.

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Lehman, Vance T; Murphy, Robert C; Schenck, Louis A; Carter, Rickey E; Johnson, Geoffrey B; Kotsenas, Amy L; Morris, Jonathan M; Nathan, Mark A; Wald, John T; Maus, Timothy P

2016-01-01

We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated. We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium-99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc-MDP SPECT/CT) and MRI with at least one fat-suppressed T2- or T1-weighted sequence with gadolinium enhancement within a 180-day interval, at our institution between 1 January 2008 and 19 February 2013. Facet joint activity on 99mTc-MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the two examination types were determined with the κ and prevalence-adjusted bias-adjusted κ (PABAK) statistics. This study included 60 patients (28 male, 47%), with a mean age of 49±19.7 years (range, 12-93 years). The κ value indicated no agreement between 99mTc-MDP SPECT/CT and MRI (κ=-0.026; 95% confidence interval: -0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the κ values. Together, the κ and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent. Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc-MDP SPECT/CT activity. MRI and 99mTc-MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research.

Isolation and Characterization of Human Mesenchymal Stem Cells From Facet Joints and Interspinous Ligaments.

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Kristjánsson, Baldur; Limthongkul, Worawat; Yingsakmongkol, Wicharn; Thantiworasit, Pattarawat; Jirathanathornnukul, Napaphat; Honsawek, Sittisak

2016-01-01

A descriptive in vitro study on isolation and differentiation of human mesenchymal stem cells (MSCs) derived from the facet joints and interspinous ligaments. To isolate cells from the facet joints and interspinous ligaments and investigate their surface marker profile and differentiation potentials. Lumbar spinal canal stenosis and ossification of the posterior longitudinal ligament are progressive conditions characterized by the hypertrophy and ossification of ligaments and joints within the spinal canal. MSCs are believed to play a role in the advancement of these diseases and the existence of MSCs has been demonstrated within the ligamentum flavum and posterior longitudinal ligament. The aim of this study was to investigate whether these cells could also be found within facet joints and interspinous ligaments. Samples were harvested from 10 patients undergoing spinal surgery. The MSCs from facet joints and interspinous ligaments were isolated using direct tissue explant technique. Cell surface antigen profilings were performed via flow cytometry. Their lineage differentiation potentials were analyzed. The facet joints and interspinous ligaments-derived MSCs have the tri-lineage potential to be differentiated into osteogenic, adipogenic, and chondrogenic cells under appropriate inductions. Flow cytometry analysis revealed both cell lines expressed MSCs markers. Both facet joints and interspinous ligaments-derived MSCs expressed marker genes for osteoblasts, adipocytes, and chondrocytes. The facet joints and interspinous ligaments may provide alternative sources of MSCs for tissue engineering applications. The facet joints and interspinous ligaments-derived MSCs are part of the microenvironment of the human ligaments of the spinal column and might play a crucial role in the development and progression of degenerative spine conditions.

The prevalence of lumbar facet joint edema in patients with low back pain

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Friedrich, Klaus M.; Pinker, Katja; Trattnig, Siegfried; Nemec, Stefan; Peloschek, Philipp; Weber, Michael

2007-01-01

The objective was to assess the prevalence of lumbar facet joint edema in patients with low back pain. Lumbar spine MR examinations (1.5 T) of 145 consecutive patients (87 women, 58 men; mean age 52.8, range 17-94 years) were retrospectively evaluated with regard to the presence of facet joint edema. The MR protocol included sagittal short-tau inversion recovery (STIR), T1- and T2-weighted as well as transverse T2-weighted images. In 9 patients follow-up MR examinations were performed and results were compared with pain. The agreement between the change in intensity of facet joint edema and the change in intensity of pain was assessed using kappa statistics and Kendall's tau coefficient. In 21 of the 145 patients (14%) edema was found at the facet joints: in 52.4% at L4/5, in 19.0% at L5/S1, in 14.3% at L4/5 and L5/S1, in 9.5% at L3/4 and L4/5, and in 4.8% at L3/4. The agreement between the change in pain score and intensity of edema within the follow-up group was ''almost perfect'' (kappa = 0.81). Kendall's tau coefficient was 0.91, indicating high agreement. Sagittal STIR images detect facet joint edema in 14% of patients with low back pain. This fact may be useful for planning treatment including facet joint injections. (orig.)

MR imaging and CT in osteoarthritis of the lumbar facet joints

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Weishaupt, D.; Zanetti, M.; Hodler, J.; Boos, N.

1999-01-01

Objective. To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination. Design and patients. Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated. Results. The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2. Conclusion. With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration. (orig.)

Quantitative in vivo MRI evaluation of lumbar facet joints and intervertebral discs using axial T2 mapping.

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Stelzeneder, David; Messner, Alina; Vlychou, Marianna; Welsch, Goetz H; Scheurecker, Georg; Goed, Sabine; Pieber, Karin; Pflueger, Verena; Friedrich, Klaus M; Trattnig, Siegfried

2011-11-01

To assess the feasibility of T2 mapping of lumbar facet joints and intervertebral discs in a single imaging slab and to compare the findings with morphological grading. Sixty lumbar spine segments from 10 low back pain patients and 5 healthy volunteers were examined by axial T2 mapping and morphological MRI at 3.0 Tesla. Regions of interest were drawn on a single slice for the facet joints and the intervertebral discs (nucleus pulposus, anterior and posterior annulus fibrosus). The Weishaupt grading was used for facet joints and the Pfirrmann score was used for morphological disc grading ("normal" vs. "abnormal" discs). The inter-rater agreement was excellent for the facet joint T2 evaluation (r = 0.85), but poor for the morphological Weishaupt grading (kappa = 0.15). The preliminary results show similar facet joint T2 values in segments with normal and abnormal Pfirrmann scores. There was no difference in mean T2 values between facet joints in different Weishaupt grading groups. Facet joint T2 values showed a weak correlation with T2 values of the posterior annulus (r = 0.32) This study demonstrates the feasibility of a combined T2 mapping approach for the facet joints and intervertebral discs using a single axial slab.

Quantitative in vivo MRI evaluation of lumbar facet joints and intervertebral discs using axial T2 mapping

International Nuclear Information System (INIS)

Stelzeneder, David; Messner, Alina; Scheurecker, Georg; Goed, Sabine; Friedrich, Klaus M.; Trattnig, Siegfried; Vlychou, Marianna; Welsch, Goetz H.; Pieber, Karin; Pflueger, Verena

2011-01-01

To assess the feasibility of T2 mapping of lumbar facet joints and intervertebral discs in a single imaging slab and to compare the findings with morphological grading. Sixty lumbar spine segments from 10 low back pain patients and 5 healthy volunteers were examined by axial T2 mapping and morphological MRI at 3.0 Tesla. Regions of interest were drawn on a single slice for the facet joints and the intervertebral discs (nucleus pulposus, anterior and posterior annulus fibrosus). The Weishaupt grading was used for facet joints and the Pfirrmann score was used for morphological disc grading (''normal'' vs. ''abnormal'' discs). The inter-rater agreement was excellent for the facet joint T2 evaluation (r = 0.85), but poor for the morphological Weishaupt grading (kappa = 0.15). The preliminary results show similar facet joint T2 values in segments with normal and abnormal Pfirrmann scores. There was no difference in mean T2 values between facet joints in different Weishaupt grading groups. Facet joint T2 values showed a weak correlation with T2 values of the posterior annulus (r = 0.32) This study demonstrates the feasibility of a combined T2 mapping approach for the facet joints and intervertebral discs using a single axial slab. (orig.)

In vivo facet joint loading of the canine lumbar spine.

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Buttermann, G R; Schendel, M J; Kahmann, R D; Lewis, J L; Bradford, D S

1992-01-01

This study describes a technique to measure in vivo loads and the resultant load-contact locations in the facet joint of the canine lumbar spine. The technique is a modification of a previously described in vitro method that used calibrated surface strains of the lateral aspect of the right L3 cranial articular process. In the present study, strains were measured during various in vivo static and dynamic activities 3 days after strain gage implantation. The in vivo recording technique and its errors, which depend on the location of the applied facet loads, is described. The results of applying the technique to five dogs gave the following results. Relative resultant contact load locations on the facet tended to be in the central and caudal portion of the facet in extension activities, central and cranial in standing, and cranial and ventral in flexion or right-turning activities. Right-turning contact locations were ventral and cranial to left-turning locations. Resultant load locations at peak loading during walking were in the central region of the facet, whereas resultant load locations at minimum loading during walking were relatively craniad. This resultant load-contact location during a walk gait cycle typically migrated in an arc with a displacement of 4 mm from minimum to maximum loading. Static tests resulted in a range of facet loads of 0 N in flexion and lying to 185 N for two-legged standing erect, and stand resulted in facet loads of 26 +/- 15 N (mean +/- standard deviation [SD]). Dynamic tests resulted in peak facet loads ranging from 55 N while walking erect to 170 N for climbing up stairs. Maximum walk facet loads were 107 +/- 27 N. The technique is applicable to in vivo studies of a canine facet joint osteoarthritis model and may be useful for establishing an understanding of the biomechanics of low-back pain.

Congenital absence of the lumbar facet joint associated with bilateral spondylolysis of the fifth lumbar vertebra.

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Wang, Zhuo; Sakakibara, Toshihiko; Kasai, Yuichi

2013-01-01

A 14-year-old boy presented with a rare case of congenital absence of lumbar facet joint manifesting as low back pain. Physical examination showed no neurological or hematologic abnormalities. Radiography revealed absence of a facet joint on the right side of L4-5. Computed tomography and three-dimensional computed tomography revealed absence of the facet joint on the right side of L4-5 and spondylolysis on both sides of L5. Pain subsided after conservative treatment. This is an extremely rare case of congenital absence of lumbar facet joint associated with bilateral spondylolysis.

Intraarticular Pulsed Radiofrequency to Treat Refractory Lumbar Facet Joint Pain in Patients with Low Back Pain.

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Chang, Min Cheol; Cho, Yun-Woo; Ahn, Da Hyun; Do, Kyung Hee

2018-04-01

Many treatment techniques have been used for refractory lumbar facet joint pain; however, their efficacy has been controversial. In this study, we investigated the clinical efficacy and safety of intra-articular pulsed radiofrequency for the treatment of refractory lumbar facet joint pain in patients with low back pain. Twenty patients with refractory lumbar facet joint pain were recruited, and each patient was treated via intra-articular pulsed radiofrequency. The treatment effects were measured with a numerical rating scale, and the technical accuracy of intra-articular pulsed radiofrequency treatment was evaluated independently by 2 radiologists. Any adverse events or complications also were checked. We performed intra-articular pulsed radiofrequency treatment at 48 levels of the lumbar facet joints in 20 patients (5 men and 15 women; mean age, 64.50 ± 10.65 years) with refractory lumbar facet joint pain. Pain scores were significantly reduced at 1 month, 3 months, and 6 months after treatment (P radiofrequency results in all 20 patients, without any serious adverse effects. Treatment using intra-articular pulsed radiofrequency is an alternative to other techniques in patients with refractory lumbar facet joint pain. Copyright © 2018 Elsevier Inc. All rights reserved.

Inter-rater reliability of diagnostic criteria for sacroiliac joint-, disc- and facet joint pain.

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van Tilburg, Cornelis W J; Groeneweg, Johannes G; Stronks, Dirk L; Huygen, Frank J P M

2017-01-01

Several diagnostic criteria sets are described in the literature to identify low back pain subtypes, but very little is known about the inter-rater reliability of these criteria. We conducted a study to determine the reliability of diagnostic tests that point towards SI joint-, disc- or facet joint pain. Inter-rater reliability study alongside three randomized clinical trials. Multidisciplinary pain center of general hospital. Patients aged 18 or more with medical history and physical examination suggestive of sacroiliac joint-, disc- and facet joint pain on lumbar level. Making use of nowadays most common used diagnostic criteria, a physical examination is taken independently by three physicians (two pain physicians and one orthopedic surgeon). Inter-rater reliability (Kappa (κ) measure of agreement) and significance (p) between raters are presented. Strengths of agreement, indicated with κ values above 0,20, are presented in order of agreement. One hundred patients were included. None of the parameters from the physical investigation had κ values of more than 0.21 (fair) in all pairs of raters. Between two raters (C and D), there was an almost perfect agreement on three parameters, more specifically ``Abnormal sensory and motor examination, hyperactive or diminished reflexes'', ``Sitting exam shows no reflex, motor or sensory signs in the legs'' and ``Straight leg raising (Laségue) negative between 30 and 70 degrees of flexion''. The ``Drop test positive'' parameters had moderate strength of agreement between raters A and D and fair strength between raters A and B. The ``Digital interspinous pressure test positive'' had moderate strength of agreement between raters C and D and fair strength of agreement between raters A and B as well as raters B and C. Three other parameters had a fair strength of agreement between two raters, all other parameters had a slight or poor strength of agreement. Inter-rater reliability, confidence intervals and significance of

Contribution of facet joints, axial compression, and composition to human lumbar disc torsion mechanics.

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Bezci, Semih E; Eleswarapu, Ananth; Klineberg, Eric O; O'Connell, Grace D

2018-02-12

Stresses applied to the spinal column are distributed between the intervertebral disc and facet joints. Structural and compositional changes alter stress distributions within the disc and between the disc and facet joints. These changes influence the mechanical properties of the disc joint, including its stiffness, range of motion, and energy absorption under quasi-static and dynamic loads. There have been few studies evaluating the role of facet joints in torsion. Furthermore, the relationship between biochemical composition and torsion mechanics is not well understood. Therefore, the first objective of this study was to investigate the role of facet joints in torsion mechanics of healthy and degenerated human lumbar discs under a wide range of compressive preloads. To achieve this, each disc was tested under four different compressive preloads (300-1200 N) with and without facet joints. The second objective was to develop a quantitative structure-function relationship between tissue composition and torsion mechanics. Facet joints have a significant contribution to disc torsional stiffness (∼60%) and viscoelasticity, regardless of the magnitude of axial compression. The findings from this study demonstrate that annulus fibrosus GAG content plays an important role in disc torsion mechanics. A decrease in GAG content with degeneration reduced torsion mechanics by more than an order of magnitude, while collagen content did not significantly influence disc torsion mechanics. The biochemical-mechanical and compression-torsion relationships reported in this study allow for better comparison between studies that use discs of varying levels of degeneration or testing protocols and provide important design criteria for biological repair strategies. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Intra-articular nerve growth factor regulates development, but not maintenance, of injury-induced facet joint pain & spinal neuronal hypersensitivity.

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Kras, J V; Kartha, S; Winkelstein, B A

2015-11-01

The objective of the current study is to define whether intra-articular nerve growth factor (NGF), an inflammatory mediator that contributes to osteoarthritic pain, is necessary and sufficient for the development or maintenance of injury-induced facet joint pain and its concomitant spinal neuronal hyperexcitability. Male Holtzman rats underwent painful cervical facet joint distraction (FJD) or sham procedures. Mechanical hyperalgesia was assessed in the forepaws, and NGF expression was quantified in the C6/C7 facet joint. An anti-NGF antibody was administered intra-articularly in additional rats immediately or 1 day following facet distraction or sham procedures to block intra-articular NGF and test its contribution to initiation and/or maintenance of facet joint pain and spinal neuronal hyperexcitability. NGF was injected into the bilateral C6/C7 facet joints in separate rats to determine if NGF alone is sufficient to induce these behavioral and neuronal responses. NGF expression increases in the cervical facet joint in association with behavioral sensitivity after that joint's mechanical injury. Intra-articular application of anti-NGF immediately after a joint distraction prevents the development of both injury-induced pain and hyperexcitability of spinal neurons. Yet, intra-articular anti-NGF applied after pain has developed does not attenuate either behavioral or neuronal hyperexcitability. Intra-articular NGF administered to the facet in naïve rats also induces behavioral hypersensitivity and spinal neuronal hyperexcitability. Findings demonstrate that NGF in the facet joint contributes to the development of injury-induced joint pain. Localized blocking of NGF signaling in the joint may provide potential treatment for joint pain. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Evaluation of the relationship between age, gender, and body mass index, and lumbar facet joint pain

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Arman Taheri

2016-01-01

Full Text Available Introduction: Lumbar facet joint pain accounts for 5-15% of the cases of chronic, axial low back pain. Most commonly, facetogenic pain is the result of repetitive stress and/or cumulative low level trauma, leading to inflammation and stretching of the joint capsule. Patients and Methods: In this descriptive study 76 patients who were diagnosed, after a diagnostic block, as having lumbar facet joint pain were evaluated by their age, sex, and body mass index (BMI. Data were collected according to a checklist and entered to SPSS version 16. Results: The mean age of the participants was 48.53 years; the participants included 44 women and 32 men. Lumbar facet joint pain was more frequent in the age range of 40-55 years. With respect to BMI, lumbar facet joint pain was most frequently seen in patients with BMI of 24.5-29.5 kg/m 2 (40.8%. Conclusion: Based on our findings, the chances of developing lumbar facet joint pain is more in women who are between 40 years and 55 years of age and whose BMI is 24.5-29.5 kg/m 2 .

Detailed examination of the lower cervical spine facet joints in a road traffic crash fatality - a case study

DEFF Research Database (Denmark)

Uhrenholt, Lars; Nielsen, Edith; Vesterby, Annie

2005-01-01

The lower cervical spine facet joints of a road traffic crash fatality were examined using diagnostic imaging and histological techniques. No injuries to the cervical spine facet joints could be identified with diagnostic imaging including conventional radiology, CT and MRI. Examination of stained...... histological sections visualised the morphology and integrity of the facet joints in detail. Occult injuries to and in close proximity of the cervical spine facet joints were identified only on histological examination....

Delayed onset of a spinal epidural hematoma after facet joint injection

Directory of Open Access Journals (Sweden)

Mirko Velickovic

2016-10-01

Full Text Available The treatment of chronic back pain is a challenging problem. Facet joint infiltration is an established treatment for chronic low back pain caused by arthrosis of the lumbar facet joints. Due to the increasing number of patients with chronic low back pain, this therapy has become more frequent. We treated a 51-year-old male patient, who developed an epidural hematoma 2 months after infiltration therapy. Our case shows that even a delayed onset of spinal epidural hematoma is possible and should be kept in mind as a possible cause of acute myelopathy after spinal intervention.

Qualitative and quantitative assessment of degeneration of cervical intervertebral discs and facet joints.

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Walraevens, Joris; Liu, Baoge; Meersschaert, Joke; Demaerel, Philippe; Delye, Hans; Depreitere, Bart; Vander Sloten, Jos; Goffin, Jan

2009-03-01

Degeneration of intervertebral discs and facet joints is one of the most frequently encountered spinal disorders. In order to describe and quantify degeneration and evaluate a possible relationship between degeneration and biomechanical parameters, e.g., the intervertebral range of motion and intradiscal pressure, a scoring system for degeneration is mandatory. However, few scoring systems for the assessment of degeneration of the cervical spine exist. Therefore, two separate objective scoring systems to qualitatively and quantitatively assess the degree of cervical intervertebral disc and facet joint degeneration were developed and validated. The scoring system for cervical disc degeneration consists of three variables which are individually scored on neutral lateral radiographs: "height loss" (0-4 points), "anterior osteophytes" (0-3 points) and "endplate sclerosis" (0-2 points). The scoring system for facet joint degeneration consists of four variables which are individually scored on neutral computed tomography scans: "hypertrophy" (0-2 points), "osteophytes" (0-1 point), "irregularity" on the articular surface (0-1 point) and "joint space narrowing" (0-1 point). Each variable contributes with varying importance to the overall degeneration score (max 9 points for the scoring system of cervical disc degeneration and max 5 points for facet joint degeneration). Degeneration of 20 discs and facet joints of 20 patients was blindly assessed by four raters: two neurosurgeons (one senior and one junior) and two radiologists (one senior and one junior), firstly based on first subjective impression and secondly using the scoring systems. Measurement errors and inter- and intra-rater agreement were determined. The measurement error of the scoring system for cervical disc degeneration was 11.1 versus 17.9% of the subjective impression results. This scoring system showed excellent intra-rater agreement (ICC = 0.86, 0.75-0.93) and excellent inter-rater agreement (ICC = 0

Investigation of stresses in facetted glass shell structures

DEFF Research Database (Denmark)

Bagger, Anne; Jönsson, Jeppe; Wester, Ture

2007-01-01

by in-plane forces in the facets and the transfer of distributed in-plane forces across the joints. It is described how these facets work structurally, specifically how bending moments develop and cause possible stress concentrations in the corners, which are subjected to uplift. Apart from local...... bending moments from distributed load, other types of bending moments are likely to occur, especially if the shell has areas of low stiffness, for example along a free edge. A facetted shell structure has been modelled in a finite element program, and the resulting stresses are presented and discussed....

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease

International Nuclear Information System (INIS)

Morrison, J.L.; Kaplan, P.A.; Dussault, R.G.; Anderson, M.W.

2000-01-01

Objective. Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease.Design. Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease.Results. Five percent (46/890) of lumbar pedicles in 23 patients had marrow signal intensity changes. Ninety-one percent (42/46) of the abnormal pedicles had adjacent degenerative joint disease of the facets, while only 21% (189/890) of normal pedicles had adjacent facet degenerative joint disease (p<0.001). Eighty-nine percent (41/46) of the pedicles with marrow signal intensity changes had adjacent degenerative disc disease.Conclusions. Pedicle marrow signal intensity changes are not a specific sign of spondylolysis; they are commonly seen with adjacent facet degenerative joint disease in the absence of spondylolysis. Pedicle marrow signal intensity changes are probably a response to abnormal stresses related to abnormal motion or loading caused by the degenerative changes in the spinal segment. (orig.)

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease

Energy Technology Data Exchange (ETDEWEB)

Morrison, J.L.; Kaplan, P.A.; Dussault, R.G.; Anderson, M.W. [Dept. of Radiology, Univ. of Virginia Health System, Charlottesville, VA (United States)

2000-12-01

Objective. Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease.Design. Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease.Results. Five percent (46/890) of lumbar pedicles in 23 patients had marrow signal intensity changes. Ninety-one percent (42/46) of the abnormal pedicles had adjacent degenerative joint disease of the facets, while only 21% (189/890) of normal pedicles had adjacent facet degenerative joint disease (p<0.001). Eighty-nine percent (41/46) of the pedicles with marrow signal intensity changes had adjacent degenerative disc disease.Conclusions. Pedicle marrow signal intensity changes are not a specific sign of spondylolysis; they are commonly seen with adjacent facet degenerative joint disease in the absence of spondylolysis. Pedicle marrow signal intensity changes are probably a response to abnormal stresses related to abnormal motion or loading caused by the degenerative changes in the spinal segment. (orig.)

Optimized cervical spine bone SPET for detection of facet joint injury after whiplash injury

Energy Technology Data Exchange (ETDEWEB)

Cardaci, G T; Bower, G D; Taylor, J [Perth and Perth Pain Management, South Perth, WA (Australia). Mount Medical Centre, Isotope Imaging

1999-04-01

Full text: The most frequent origin for chronic cervical pain in patients with a remote history of whiplash injury is the cervical facet joints. Exact localization of facet joint injury is difficult and currently advocated methods include multiple invasive diagnostic injections. Optimization of {sup 99}Tc{sup m}-HDP cervical SPET (CSPET) to accurately localize facet joint pathology was attempted and the results correlated with clinical localization relying on focal joint tenderness and passive movement methods. Imaging was performed on a dual-headed gamma camera system using an elliptical orbit over 360 deg. The patient's neck was flexed to eliminate the cervical lordosis. Reconstructed CSPET images were reorientated into the long axis of the vertebral bodies. CSPET studies were independently scored by two observers blinded to the clinical and other imaging information and correlated with clinical localization and response to radiofrequency ablation. 54 patients have been studied using this technique in a prospective study. Early patient follow-up data will be presented. CSPET was felt to be clinically useful by pain therapists in targeting treatment.

Optimized cervical spine bone SPET for detection of facet joint injury after whiplash injury

International Nuclear Information System (INIS)

Cardaci, G.T.; Bower, G.D.; Taylor, J.

1999-01-01

Full text: The most frequent origin for chronic cervical pain in patients with a remote history of whiplash injury is the cervical facet joints. Exact localization of facet joint injury is difficult and currently advocated methods include multiple invasive diagnostic injections. Optimization of 99 Tc m -HDP cervical SPET (CSPET) to accurately localize facet joint pathology was attempted and the results correlated with clinical localization relying on focal joint tenderness and passive movement methods. Imaging was performed on a dual-headed gamma camera system using an elliptical orbit over 360 deg. The patient's neck was flexed to eliminate the cervical lordosis. Reconstructed CSPET images were reorientated into the long axis of the vertebral bodies. CSPET studies were independently scored by two observers blinded to the clinical and other imaging information and correlated with clinical localization and response to radiofrequency ablation. 54 patients have been studied using this technique in a prospective study. Early patient follow-up data will be presented. CSPET was felt to be clinically useful by pain therapists in targeting treatment

Talocalcaneal Joint Middle Facet Coalition Resection With Interposition of a Juvenile Hyaline Cartilage Graft.

Science.gov (United States)

Tower, Dyane E; Wood, Ryan W; Vaardahl, Michael D

2015-01-01

Talocalcaneal joint middle facet coalition is the most common tarsal coalition, occurring in ≤2% of the population. Fewer than 50% of involved feet obtain lasting relief of symptoms after nonoperative treatment, and surgical intervention is commonly used to relieve symptoms, increase the range of motion, improve function, reconstruct concomitant pes planovalgus, and prevent future arthrosis from occurring at the surrounding joints. Several approaches to surgical intervention are available for patients with middle facet coalitions, ranging from resection to hindfoot arthrodesis. We present a series of 4 cases, in 3 adolescent patients, of talocalcaneal joint middle facet coalition resection with interposition of a particulate juvenile hyaline cartilaginous allograft (DeNovo(®) NT Natural Tissue Graft, Zimmer, Inc., Warsaw, IN). With a mean follow-up period of 42.8 ± 2.9 (range 41 to 47) months, the 3 adolescent patients in the present series were doing well with improved subtalar joint motion and decreased pain, and 1 foot showed no bony regrowth on a follow-up computed tomography scan. The use of a particulate juvenile hyaline cartilaginous allograft as interposition material after talocalcaneal middle facet coalition resection combined with adjunct procedures to address concomitant pes planovalgus resulted in good short-term outcomes in 4 feet in 3 adolescent patients. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Evaluation of Water Content in Lumbar Intervertebral Discs and Facet Joints Before and After Physiological Loading Using T2 Mapping MRI.

Science.gov (United States)

Yamabe, Daisuke; Murakami, Hideki; Chokan, Kou; Endo, Hirooki; Oikawa, Ryosuke; Sawamura, Shoitsu; Doita, Minoru

2017-12-15

T2 mapping was used to quantify the water content of lumbar spine intervertebral discs (IVDs) and facet joints before and after physiological loading. The aim of this study was to clarify the interaction between lumbar spine IVD and facet joints as load-bearing structures by measuring the water content of their matrix after physiological loading using T2 mapping magnetic resonance imaging (MRI). To date, few reports have functionally evaluated lumbar spine IVD and facet joints, and their interaction in vivo. T2 mapping may help detect changes in the water content of IVD and articular cartilage of facet joints before and after physiological loading, thereby enabling the evaluation of changes in interacted water retention between IVD and facet joints. Twenty asymptomatic volunteers (10 female and 10 male volunteers; mean age, 19.3 years; age range, 19-20 years) underwent MRI before and after physiological loading such as lumbar flexion, extension, and rotation. Each IVD from L1/2 to L5/S1 was sliced at center of the disc space, and the T2 value was measured at the nucleus pulposus (NP), anterior annulus fibrosus (AF), posterior AF, and bilateral facet joints. In the NP, T2 values significantly decreased after exercise at every lumbar spinal level. In the anterior AF, there were no significant differences in T2 values at any level. In the posterior AF, T2 values significantly increased only at L4/5. In the bilateral facet joints, T2 values significantly decreased after exercise at every level. There was a significant decrease in the water content of facet joints and the NP at every lumbar spinal level after dynamic loading by physical lumbar exercise. These changes appear to play an important and interactional role in the maintenance of the interstitial matrix in the IVD NP and cartilage in the facet joint. 3.

Lumbar facet joint fat pads: Their normal anatomy and their appearance when enlarged

International Nuclear Information System (INIS)

Taylor, J.R.; McCormick, C.C.

1991-01-01

The polar recesses, superior and inferior to lumbar facet joints, are filled by fat pads from which fat-filled synovial folds project between the articular surfaces for a distance of two to four millimetres. The intracapsular superior recess lies between the ligamentum flavum and the lamina above. The extracapsular inferior recess lies on the back of the lamina below and communicates with the joint through a hole in the inferior capsule. The intracapsular folds move freely in and out of the joint during movements. These features are demonstrated in anatomic studies using transverse sections and radiologic studies using computed tomography. In about 4% of lumbar spines examined, the intraarticular fat pads are enlarged and extend from the joint recess(es) into the middle third of one or more facet joints. The fat pads can be identified in CT scans by their radiolucency and distinguished from vacuum phenomenon by measuring their attenuation values. The cause of the intra-articular enlargement of the fat pads is unknown, but it is suggested that their extension into the middle third of the joint may be secondary to degenerative change in the motion segment with capsular laxity in the affected joint. (orig.)

Histological Osteoarthritic Changes in the Human Cervical Spine Facet Joints Related to Age and Gender

DEFF Research Database (Denmark)

Uhrenholt, Lars; Charles, Annie Vesterby; Gregersen, Markil

2018-01-01

STUDY DESIGN: Cross-sectional autopsy study. OBJECTIVE: Quantify histological changes in the lower cervical spine facet joints with regard to age and gender using systematic random sampling of entire joints. SUMMARY OF BACKGROUND DATA: Neck pain is a common debilitating musculoskeletal condition...... and one of the highest ranked causes of years lived with disability. The cause of neck pain is multifactorial and osteoarthritis is one potential cause. The cervical spine facet joints have been implicated in the aetiology of chronic neck pain. Hence, a detailed description of their anatomy and age......- and gender related changes is needed. METHODS: The lower four cervical spine segments (C4-C7 included) were obtained from 72 subjects during autopsy; 29 females (median age 53 years [22-77]) and 43 males (median age 38 years [20-78]). A total of 1132 articular facets were embedded in toto in hard plastic...

Audit of conservative management of chronic low back pain in a secondary care setting--part I: facet joint and sacroiliac joint interventions.

Science.gov (United States)

Chakraverty, Robin; Dias, Richard

2004-12-01

The work of a chronic back pain service in secondary care in the West Midlands is reported. The service offers acupuncture, spinal injection procedures, osteopathy and a range of other interventions for patients whose back pain has not responded to conservative management. This section of the report focuses on injection procedures for lumbar facet joint and sacroiliac joint pain, which have been shown to be the cause of chronic low back pain in 16-40% and 13-19% of patients respectively. Diagnosis relies on the use of intra-articular or sensory nerve block injections with local anaesthetic. Possible treatments following diagnosis include intra-articular corticosteroid, radiofrequency denervation (for facet joint pain) or ligament prolotherapy injections (for sacroiliac joint pain). The results of several hospital audits are reported. At six month follow up, 50% of 38 patients undergoing radiofrequency denervation following diagnostic blocks for facet joint pain had improved by more than 50%, compared to 29% of 34 patients treated with intra-articular corticosteroid injection. Sixty three per cent of 19 patients undergoing prolotherapy following diagnostic block injection for sacroiliac joint pain had improved at six months, compared to 33% of 33 who had intra-articular corticosteroid. Both radiofrequency denervation and sacroiliac prolotherapy showed good long-term outcomes at one year.

A Best-Evidence Systematic Appraisal of the Diagnostic Accuracy and Utility of Facet (Zygapophysial) Joint Injections in Chronic Spinal Pain.

Science.gov (United States)

Boswell, Mark V; Manchikanti, Laxmaiah; Kaye, Alan D; Bakshi, Sanjay; Gharibo, Christopher G; Gupta, Sanjeeva; Jha, Sachin Sunny; Nampiaparampil, Devi E; Simopoulos, Thomas T; Hirsch, Joshua A

2015-01-01

Spinal zygapophysial, or facet, joints are a source of axial spinal pain and referred pain in the extremities. Conventional clinical features and other noninvasive diagnostic modalities are unreliable in diagnosing zygapophysial joint pain. A systematic review of the diagnostic accuracy of spinal facet joint nerve blocks. To determine the diagnostic accuracy of spinal facet joint nerve blocks in chronic spinal pain. A methodological quality assessment of included studies was performed using Quality Appraisal of Reliability Studies (QAREL). Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. The level of evidence was classified as Level I to V based on the grading of evidence utilizing best evidence synthesis. Data sources included relevant literature identified through searches of PubMed and other electronic searches published from 1966 through March 2015, Cochrane reviews, and manual searches of the bibliographies of known primary and review articles. Studies must have been performed utilizing controlled local anesthetic blocks. The criterion standard must have been at least 50% pain relief from baseline scores and the ability to perform previously painful movements. The available evidence is Level I for lumbar facet joint nerve blocks with the inclusion of a total of 17 studies with dual diagnostic blocks, with at least 75% pain relief with an average prevalence of 16% to 41% and false-positive rates of 25% to 44%. The evidence for diagnosis of cervical facet joint pain with cervical facet joint nerve blocks is Level II based on a total of 11 controlled diagnostic accuracy studies, with significant variability among the prevalence in a heterogenous population with internal inconsistency. The prevalence rates ranged from 36% to 67% with at least 80% pain relief as the criterion standard and a false-positive rate of 27% to 63%. The level of evidence for the diagnostic accuracy of thoracic facet

MR-guided facet joint injection therapy using an open 1.0-T MRI system: an outcome study

International Nuclear Information System (INIS)

Freyhardt, Patrick; Bucourt, Maximilian de; Maurer, Martin; Renz, Diane; Gebauer, Bernhard; Hamm, Bernd; Streitparth, Florian; Hartwig, Tony; Teichgraeber, Ulf K.M.

2013-01-01

To evaluate the accuracy, safety and efficacy of magnetic resonance imaging (MRI)-guided facet joint injection therapy using a 1.0-T open MRI. One hundred and sixty-six facet joint blocks in 45 patients with lower back pain were performed under MR fluoroscopic guidance using a proton-density-weighted turbo-spin-echo sequence. An in-room monitor, wireless MR-mouse for operator-controlled multiplanar navigation, a flexible surface coil and MR-compatible 20-G needle were used. Clinical outcome was evaluated by questionnaire before intervention and after 1 week, 3, 6 and 12 months using a numerical visual analogue scale (VAS). All facet joint blocks were considered technically successful with distribution of the injectant within and/or around the targeted facet joint. No major complications occurred. The final outcome analysis included 38 patients. An immediate effect was reported by 63 % of the patients. A positive mid-/long-term effect was seen in 13 patients (34 %) after 6 months and in 9 patients (24 %) after 12 months. Mean VAS was reduced from 7.1 ± 1.7 (baseline) to 3.5 ± 2.2, 4.1 ± 3.0, 3.8 ± 2.9 and 4.6 ± 2.9 at 1 week, 3, 6 and 12 months (P < 0.01). MR-guided facet joint injection therapy of the lumbosacral spine is accurate, safe and efficient in the symptomatic treatment of lower back pain. (orig.)

Desmoid type fibromatosis in the facet joint of lumbar spine: Case report and review of literature

Energy Technology Data Exchange (ETDEWEB)

Kim, So Jung; Ha, Doo Hoe; Lee, Sang Min; Kang, Hae Youn [CHA Bundang Medical Center, CHA University, Seongnam (Korea, Republic of)

2013-10-15

Desmoid type fibromatosis is a benign fibroblastic tumor arising from the fascia or musculoaponeurosis. It may occur in various locations, but most commonly in the shoulder girdle and neck; to our knowledge, there has been no reported case originating from a facet joint of the spine. We report CT and MR imaging findings of a desmoid type fibromatosis, involving the facet joint of the L3-4 spine with bone involvement.

Association between facet joint osteoarthritis and the Oswestry Disability Index.

Science.gov (United States)

Maataoui, Adel; Vogl, Thomas J; Middendorp, Marcus; Kafchitsas, Konstantinos; Khan, M Fawad

2014-11-28

To investigate the correlation of facet joint osteoarthritis (FJOA) at lumbar levels L4/L5 and L5/S1 and the Oswestry Disability Index (ODI). The study involved lumbar MRIs of 591 patients with a mean age of 47.3 years. The MRIs of the lumbar spine were performed on a 1.5 Tesla scanner (Magnetom(®) Avanto, Siemens AG, Erlangen, Germany) using a dedicated receive only spine coil. After initial blinding, each dataset was evaluated by 2 board certified radiologist with more than 5 years experience in musculoskeletal imaging. In total 2364 facet joints were graded. Degenerative changes of the facet joints were evaluated according to the 4-point scale as proposed by Weishaupt et al Functional status was assessed using the ODI. The index is scored from 0 to 100 and interpreted as follows: 0%-20%, minimal disability; 20%-40%, moderate disability; 40%-60%, severe disability; 60%-80%, crippled; 80%-100%, patients are bedbound. Spearman's coefficient of rank correlation was used for statistical analysis, with significance set at P disability had a minimum of 0% and a maximum of 91.11% with an arithmetic mean of 32.77% ± 17.02%. The majority of patients (48.39%) had moderate functional disability (21%-40%). There was no significant correlation between FJOA and ODI on both sides of lumbar level L4/5 and on the left side of lumbar level L5/S1. A weak positive correlation was evaluated between ODI and FJOA on the right side of lumbar level L5/S1. The missing correlation of FJOA and ODI confirms our clinical experience that imaging alone is an insufficient approach explaining low back pain. Clinical correlation is imperative for an adequate diagnostic advance in patients with low back pain.

The possibility of the radiological and ultrasonographic examination of the facet joints of the equine thoracic and lumbar spine

International Nuclear Information System (INIS)

Reisinger, R.

2003-03-01

The facet joints of the equine thoracic and lumbar spine were examined by radiology and ultrasonography in 31 and 20 standing horses, respectively. The employed methods were evaluated. The left and right joints of 15/31 standing horses were comparatively x-rayed with both 20 o ventral oblique and 30 o dorsal oblique techniques. The independent evaluation of the ensuing films by four experienced veterinary surgeons yielded a significantly better assessment of the tested parameters in the 20 o ventral oblique technique. It was possible to depict the facet joints of the right and left sides between the caudal margin of the scapula and the diaphragm with the pulmonary field as background rich in contrast. In 20 horses, the facet joints were examined from Th10 to L6 in longitudinal and sagittal planes. A linear-array ultrasound probe with a frequency of 7,5 MHz and a convex ultrasound probe with a frequency of 3,5 MHz were used. Depending on the nutritional state, the soft tissue structures could be evaluated. The evaluation of the facet joints themselves was very limited. (author)

Bipolar Radiofrequency Facet Ablation of the Lumbar Facet Capsule: An Adjunct to Conventional Radiofrequency Ablation for Pain Management.

Science.gov (United States)

Jacobson, Robert E; Palea, Ovidiu; Granville, Michelle

2017-09-01

Radiofrequency facet ablation (RFA) has been performed using the same technique for over 50 years. Except for variations in electrode size, tip shape, and change in radiofrequency (RF) stimulation parameters, using standard, pulsed, and cooled RF wavelengths, the target points have remained absolutely unchanged from the original work describing RFA for lumbar pain control. Degenerative changes in the facet joint and capsule are the primary location for the majority of lumbar segmental pathology and pain. Multiple studies show that the degenerated facet joint is richly innervated as a result of the inflammatory overgrowth of the synovium. The primary provocative clinical test to justify an RFA is to perform an injection with local anesthetic into the facet joint and the posterior capsule and confirm pain relief. However, after a positive response, the radiofrequency lesion is made not to the facet joint but to the more proximal fine nerve branches that innervate the joint. The accepted target points for the recurrent sensory branch ignore the characteristic rich innervation of the pathologic lumbar facet capsule and assume that lesioning of these recurrent branches is sufficient to denervate the painful pathologic facet joint. This report describes the additional targets and technical steps for further coagulation points along the posterior capsule of the lumbar facet joint and the physiologic studies of the advantage of the bipolar radiofrequency current in this location. Bipolar RF to the facet capsule is a simple, extra step that easily creates a large thermo-coagulated lesion in this capsule region of the pathologic facet joint. Early studies demonstrate bipolar RF to the facet capsule can provide long-term pain relief when used alone for specific localized facet joint pain, to coagulate lumbar facet cysts to prevent recurrence, and to get more extensive pain control by combining it with traditional lumbar RFA, especially when RFA is repeated.

Fluoroscopy-guided intrA-articular facet joint steroid injection for the management of low back pain: Therapeutic effectiveness and arthrographic pattern

International Nuclear Information System (INIS)

Kim, Su Jin; Lee, Jun Woo; Lee, Guen Young; You, Ja Yeon; Kang, Heung Sik; Chai, Jae Won; Ahn, Joong Mo

2015-01-01

To evaluate the effectiveness of fluoroscopy-guided intra-articular facet joint steroid injection for the management of low back pain, and to document the incidence of epidural leakage. In total, 320 facet joint injections of 244 consecutive patients were included in this study. All patients had undergone an intra-articular facet joint steroid injection in 2007 and had follow-up post-treatment medical records. The response to treatment was analyzed on the basis of chart documentation (aggravated, no change, slightly improved, much improved, no pain). Fluoroscopic arthrograms of the injections were retrospectively analyzed by two radiologists. Of the 244 patients, 85.2% (n = 208) showed improvement after an initial intra-articular facet joint steroid injection. A total of 77.9% (n = 162) of the patients showed symptom recurrence, with a median of a 69 day symptom-free interval, while 30.3% (n = 74) of the patients showed symptom-free intervals of more than six months. Overall, 74 (33.3%) of the 222 cases of intra-articular facet joint steroid injections without concomitant epidural steroid injection showed epidural leakage in fluoroscopic arthrograms. Fluoroscopy-guided intra-articular facet joint injection is a reliable technique for the management of low back pain, with excellent immediate effectiveness and good prolonged (> 2 months) pain relief. Epidural leakage during injection was detected in one-third of the cases

Fluoroscopy-guided intrA-articular facet joint steroid injection for the management of low back pain: Therapeutic effectiveness and arthrographic pattern

Energy Technology Data Exchange (ETDEWEB)

Kim, Su Jin; Lee, Jun Woo; Lee, Guen Young; You, Ja Yeon; Kang, Heung Sik [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); Chai, Jae Won [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); Ahn, Joong Mo [Dept. of Radiology, University of Pittsburgh Medical Center, Pittsburgh (United States)

2015-09-15

To evaluate the effectiveness of fluoroscopy-guided intra-articular facet joint steroid injection for the management of low back pain, and to document the incidence of epidural leakage. In total, 320 facet joint injections of 244 consecutive patients were included in this study. All patients had undergone an intra-articular facet joint steroid injection in 2007 and had follow-up post-treatment medical records. The response to treatment was analyzed on the basis of chart documentation (aggravated, no change, slightly improved, much improved, no pain). Fluoroscopic arthrograms of the injections were retrospectively analyzed by two radiologists. Of the 244 patients, 85.2% (n = 208) showed improvement after an initial intra-articular facet joint steroid injection. A total of 77.9% (n = 162) of the patients showed symptom recurrence, with a median of a 69 day symptom-free interval, while 30.3% (n = 74) of the patients showed symptom-free intervals of more than six months. Overall, 74 (33.3%) of the 222 cases of intra-articular facet joint steroid injections without concomitant epidural steroid injection showed epidural leakage in fluoroscopic arthrograms. Fluoroscopy-guided intra-articular facet joint injection is a reliable technique for the management of low back pain, with excellent immediate effectiveness and good prolonged (> 2 months) pain relief. Epidural leakage during injection was detected in one-third of the cases.

Up-regulation of p55 TNF alpha-receptor in dorsal root ganglia neurons following lumbar facet joint injury in rats.

Science.gov (United States)

Sakuma, Yoshihiro; Ohtori, Seiji; Miyagi, Masayuki; Ishikawa, Tetsu; Inoue, Gen; Doya, Hideo; Koshi, Takana; Ito, Toshinori; Yamashita, Masaomi; Yamauchi, Kazuyo; Suzuki, Munetaka; Moriya, Hideshige; Takahashi, Kazuhisa

2007-08-01

The rat L5/6 facet joint is multisegmentally innervated from the L1 to L6 dorsal root ganglia (DRG). Tumor necrosis factor (TNF) is a known mediator of inflammation. It has been reported that satellite cells are activated, produce TNF and surround DRG neurons innervating L5/6 facet joints after facet injury. In the current study, changes in TNF receptor (p55) expression in DRG neurons innervating the L5/6 facet joint following facet joint injury were investigated in rats using a retrograde neurotransport method followed by immunohistochemistry. Twenty rats were used for this study. Two crystals of Fluorogold (FG; neurotracer) were applied into the L5/6 facet joint. Seven days after surgery, the dorsal portion of the capsule was cut in the injured group (injured group n = 10). No injury was performed in the non-injured group (n = 10). Fourteen days after the first application of FG, bilateral DRGs from T13 to L6 levels were resected and sectioned. They were subsequently processed for p55 immunohistochemistry. The number of FG labeled neurons and number of FG labeled p55-immunoreactive (IR) neurons were counted. FG labeled DRG neurons innervating the L5/6 facet joint were distributed from ipsilateral L1 to L6 levels. Of FG labeled neurons, the ratio of DRG neurons immunoreactive for p55 in the injured group (50%) was significantly higher than that in the non-injured group (13%). The ratio of p55-IR neurons of FG labeled DRG neurons was significantly higher in total L1 and L2 DRGs than that in total L3, 4, 5 and 6 DRGs in the injured group (L1 and 2 DRG, 67%; L3, 4, 5 and 6 DRG, 37%, percentages of the total number of p55-IR neurons at L1 and L2 level or L3-6 level/the total number of FG-labeled neurons at L1 and L2 level or L3-6 level). These data suggest that up-regulation of p55 in DRG neurons may be involved in the sensory transmission from facet joint injury. Regulation of p55 in DRG neurons innervating the facet joint was different between upper DRG innervated

A new technique to treat facet joint pain with pulsed radiofrequency.

Science.gov (United States)

Schianchi, Pietro Martino

2015-02-01

Facet joint pain affects 5% to 15% of the population with low back pain and the prevalence increases with age due to progression of arthritis. While conservative treatments are often unsuccessful, the scientific evidence on minimally invasive therapies such as intra-articular steroid infiltration and continuous and pulsed radiofrequency (PRF) of the medial branches is contradictory. Since PRF has recently been reported to successfully treat joint pain, a new application of this method is proposed for facetogenic lumbar pain via an intra-articular subcapsular approach. Here we reported two cases with successful treatment. A 71-year-old patient presented because of persisting pain in the left gluteal region radiating to the lateral thigh and calf when standing. Anti-inflammatory drugs produced only short-lasting insufficient relief. A 52-year-old employee was admitted in June 2012 because of axial lower lumbar pain with intermittent diffuse radiation to the right lower extremity that worsened during walking and lying down despite receiving analgesics and physiotherapy. A new approach to treat lumbar facet joint pain with PRF is simple to perform and without serious complications. In view of the good long-lasting results obtained with the two reported cases, randomized control trials are necessary to validate this new approach.

Imaging findings predicting the outcome of cervical facet joint blocks

International Nuclear Information System (INIS)

Hechelhammer, Lukas; Pfirrmann, Christian W.A.; Zanetti, Marco; Hodler, Juerg; Schmid, Marius R.; Boos, Norbert

2007-01-01

To determine which cross-sectional imaging findings predict the short-term outcome of cervical facet joint blocks (FJB) and to evaluate the effect of combined intra-/periarticular versus periarticular injection on pain. Fifty facet joints in 37 patients were included in the study. Single, unilateral FJBs in 24 patients, and bilateral single level FJBs in 13 patients were performed, respectively. In all patients, pain relief was assessed using a visual analogue scale. All computed tomography (CT) examinations were blindly reviewed by two radiologists. Osteoarthritis was rated using the Kellgren classification. The presence of combined intra-/periarticular vs. sole periarticular injection of contrast was evaluated. Kellgren Grades 0 (n=23), 1 (n=5), 2 (n=3), 3 (n=9), and 4 (n=10) were found. Mean pain relief after injection was 35% (range: 0-100%). 40% of all injections were combined intra-/periarticular. There was neither a statistically significant difference between pain relief and combined intra-/periarticular versus sole periarticular injection (p=0.64) nor the grade of osteoarthritis (p=0.49). Pain relief after cervical FJBs does not correlate with morphologic alterations seen on CT. Periarticular FJBs are not less successful than combined intra-/periarticular FJBs. (orig.)

Rotatory Subluxation and Facet Deformity in the Atlanto-occipital Joint in Patients with Chronic Atlantoaxial Rotatory Fixation: Two Case Reports.

Science.gov (United States)

Kashii, Masafumi; Masuhara, Kenta; Kaito, Takashi; Iwasaki, Motoki

2017-01-01

The relationship between the morphometry of atlantoaxial joint and chronic atlantoaxial rotatory fixation (AARF) is well known, but disorders in the atlanto-occipital joint in chronic AARF are not fully elucidated. The authors report two rare cases of secondary deformities in the atlanto-occipital joint in chronic AARF. Two patients with chronic AARF were treated with closed manipulation, skull traction and halo-vest immobilization. Clinical outcomes and radiographs were reviewed retrospectively, focusing on pathological changes in the atlanto-occipital joint using multiplanar reconstruction computed tomography and three-dimensional computed tomography images. Case 1 (12-year-old girl) had rotatory subluxation with a superior facet deformity of the atlas in the atlanto-occipital joint before the initiation of treatment. After a series of conservative treatments, both atlantoaxial and atlanto-occipital rotatory fixation could not be reduced, and both the superior facet deformity of the atlas and osteoarthritic changes in the atlanto-occipital developed. She was monitored without surgery because the disorder progressed to the spontaneous fusion of the occipital bone to the axis. Case 2 (13-year-old boy) had rotatory subluxation without facet deformity of the atlas in the atlanto-occipital joint before the initiation of treatment. However, both the superior facet deformity of the atlas and osteoarthritic changes in the atlanto-occipital developed over time, and both atlantoaxial and atlanto-occipital rotatory fixation could not be reduced after a series of conservative treatments. He still had severe neck pain and severely restricted neck mobility and underwent spinal fusion. Atlanto-occipital rotatory subluxation and facet deformity in the atlanto-occipital joint may occur after prolonged AARF. It is necessary to pay attention to pathological changes not only in the atlantoaxial joint but also in the atlanto-occipital joint, when orthopedic surgeons treat patients

Biomechanical evaluation of the impact of various facet joint lesions on the primary stability of anterior plate fixation in cervical dislocation injuries: a cadaver study: Laboratory investigation.

Science.gov (United States)

Oberkircher, Ludwig; Born, Sebastian; Struewer, Johannes; Bliemel, Christopher; Buecking, Benjamin; Wack, Christina; Bergmann, Martin; Ruchholtz, Steffen; Krüger, Antonio

2014-10-01

Injuries of the subaxial cervical spine including facet joints and posterior ligaments are common. Potential surgical treatments consist of anterior, posterior, or anterior-posterior fixation. Because each approach has its advantages and disadvantages, the best treatment is debated. This biomechanical cadaver study compared the effect of different facet joint injuries on primary stability following anterior plate fixation. Fractures and plate fixation were performed on 15 fresh-frozen intact cervical spines (C3-T1). To simulate a translation-rotation injury in all groups, complete ligament rupture and facet dislocation were simulated by dissecting the entire posterior and anterior ligament complex between C-4 and C-5. In the first group, the facet joints were left intact. In the second group, one facet joint between C-4 and C-5 was removed and the other side was left intact. In the third group, both facet joints between C-4 and C-5 were removed. The authors next performed single-level anterior discectomy and interbody grafting using bone material from the respective thoracic vertebral bodies. An anterior cervical locking plate was used for fixation. Continuous loading was performed using a servohydraulic test bench at 2 N/sec. The mean load failure was measured when the implant failed. In the group in which both facet joints were intact, the mean load failure was 174.6 ± 46.93 N. The mean load failure in the second group where only one facet joint was removed was 127.8 ± 22.83 N. In the group in which both facet joints were removed, the mean load failure was 73.42 ± 32.51 N. There was a significant difference between the first group (both facet joints intact) and the third group (both facet joints removed) (p cadaver study, primary stability of anterior plate fixation for dislocation injuries of the subaxial cervical spine was dependent on the presence of the facet joints. If the bone in one or both facet joints is damaged in the clinical setting, anterior plate

A New Technique for the Treatment of Lumbar Facet Joint Syndrome Using Intra-articular Injection with Autologous Platelet Rich Plasma.

Science.gov (United States)

Wu, Jiuping; Du, Zhenwu; Lv, Yang; Zhang, Jun; Xiong, Wei; Wang, Ruiqiang; Liu, Rui; Zhang, Guizhen; Liu, Qinyi

2016-01-01

Lumbar facet joint syndrome is currently suggested to be a main source of axial low back pain, and a large portion of axial low back pain is caused by disorders in lumbar facet joints. Intra-articular injection is one of the most common treatment methods in the early clinical application. Therefore, we attempt to seek a new injectable material, autologous platelet rich plasma (PRP), to treat lumbar facet syndrome, as well as to assess its therapeutic effectiveness and safety. A prospective clinic evaluation. The outpatient clinic of a single academic medical center. Total 19 patients with lumbar facet joint syndrome (8 men, 11 women; mean ages: 52.53 ± 6.79 years, range: 38 - 62 years) were enrolled to receive lumbar facet joint injection with autologous PRP under x-ray fluoroscopic control. Patients were followed up immediately, at one week, one month, 2 months, and 3 months following treatment, and the elements of this analysis included low back pain visual analogue scale (VAS) at rest and during flexion, Roland-Morris Disability Questionnaire (RMQ), Oswestry Disability Index (ODI), and modified MacNab criteria for the pain relief. All the 19 patients completed the intra-articular injections with autologous PRP successfully. At one week after treatment, low back pain reduced significantly compared with prior to treatment both at rest and during flexion. The outcomes were assessed as "good" or "excellent" for 9 patients (47.37%) immediately after treatment, 14 patients (73.68%) at one week, 15 patients (78.95%) at one month, 15 patients (78.95%) at 2 months, and 15 patients (78.95%) at 3 months. Statistically significant differences were observed based on RMQ and a more than 10% improvement in lumbar functional capacity was observed based on ODI between pre-treatment and post-treatment. In addition, there were no severe relevant complications during the whole process of injection and follow-up period. A control group and the curative effect observations with

Assessment of trunk muscle density using CT and its association with degenerative disc and facet joint disease of the lumbar spine.

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Sebro, Ronnie; O'Brien, Liam; Torriani, Martin; Bredella, Miriam A

2016-09-01

The purpose of this study was (1) to evaluate the association of trunk muscle density assessed by computed tomography (CT) with age, gender, and BMI and (2) to evaluate the association between trunk muscle CT density and degenerative disc and facet joint disease of the lumbar spine. The study was IRB approved and HIPAA compliant. The study group comprised 100 subjects (mean age 44.4 ± 22.2 years, 51 % male) who underwent CT of the abdomen and pelvis without intravenous contrast. Exclusion criteria included prior abdominal or spine surgery, active malignancy and scoliosis. CTs were reviewed and the attenuation of the rectus abdominis, transverse abdominis, internal and external obliques, psoas, multifidus, longissimus and gluteus maximus were measured bilaterally at consistent levels. Degenerative disc and bilateral facet joint disease were scored using established methods. Univariate analyses were performed using linear regression. Multivariate linear regression was performed to adjust for age, gender and BMI. CT density of each trunk muscle correlated inversely with age (p degenerative disc and facet joint disease in the univariate analyses (p degenerative disc and facet joint disease respectively in the multivariate analysis. Fatty infiltration of trunk musculature increases with age and BMI. Fatty infiltration of the gluteus maximus and transverse abdominis are associated with degenerative disc and facet joint disease, independent of age, gender and BMI.

Comparative Analysis of Bone Structural Parameters Reveals Subchondral Cortical Plate Resorption and Increased Trabecular Bone Remodeling in Human Facet Joint Osteoarthritis

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Cordula Netzer

2018-03-01

Full Text Available Facet joint osteoarthritis is a prominent feature of degenerative spine disorders, highly prevalent in ageing populations, and considered a major cause for chronic lower back pain. Since there is no targeted pharmacological therapy, clinical management of disease includes analgesic or surgical treatment. The specific cellular, molecular, and structural changes underpinning facet joint osteoarthritis remain largely elusive. The aim of this study was to determine osteoarthritis-related structural alterations in cortical and trabecular subchondral bone compartments. To this end, we conducted comparative micro computed tomography analysis in healthy (n = 15 and osteoarthritic (n = 22 lumbar facet joints. In osteoarthritic joints, subchondral cortical plate thickness and porosity were significantly reduced. The trabecular compartment displayed a 42 percent increase in bone volume fraction due to an increase in trabecular number, but not trabecular thickness. Bone structural alterations were associated with radiological osteoarthritis severity, mildly age-dependent but not gender-dependent. There was a lack of association between structural parameters of cortical and trabecular compartments in healthy and osteoarthritic specimens. The specific structural alterations suggest elevated subchondral bone resorption and turnover as a potential treatment target in facet joint osteoarthritis.

CT-guided intradiscal ozone injection combined with intervertebral facet joint steroid injection for lumbar disk herniation accompanied with intervertebral arthritis

International Nuclear Information System (INIS)

Zhang Li; Chen Zhaohui; Sun Xijun; Liu Jianping; Li Jiakai

2009-01-01

Objective: To compare the clinical effectiveness of ozone (O 3 ) nucleus pulposus ablation only with that of O 3 nucleus pulposus ablation combined with intervertebral facet joint injection of compound Betamethasome in treating lumbar disk herniation accompanied with intervertebral facet arthritis. Methods: Eighty patients with lumbar disk herniation and intervertebral facet arthritis were equally and randomly divided into two groups. Under CT guidance, O 3 nucleus pulposus ablation was performed in patients of group A(n=40), while O 3 nucleus pulposus ablation combined with intervertebral facet joint injection of compound Betamethasome (0.5-1 ml) was carried out in patients of group B(n=40). Using double blind method the therapeutic effectiveness was evaluated before and 1 week,3,6-months after the procedure by an Oswestry Low Back Pain Disability Questionnaire. Results: One week after the procedure the effective rate of group A and group B was 65% and 82.5% respectively. Three and six months after the treatment, the effective rate was 75% and 70% respectively for group A, while it was 90% and 92.5% respectively for group B. The difference between two groups was significant (P 3 combined with intervertebral facet joint injection of compound Betamethasome is an effective and safe treatment for lumbar disk herniation accompanied with intervertebral facet arthritis.It is worth popularizing this technique in clinical practice. (authors)

Lumbar disc degeneration was not related to spine and hip bone mineral densities in Chinese: facet joint osteoarthritis may confound the association.

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Pan, Jianjiang; Lu, Xuan; Yang, Ge; Han, Yongmei; Tong, Xiang; Wang, Yue

2017-12-01

A sample of 512 Chinese was studied and we observed that greater disc degeneration on MRI was associated with greater spine DXA BMD. Yet, this association may be confounded by facet joint osteoarthritis. BMD may not be a risk factor for lumbar disc degeneration in Chinese. Evidence suggested that lumbar vertebral bone and intervertebral disc interact with each other in multiple ways. The current paper aims to determine the association between bone mineral density (BMD) and lumbar disc degeneration using a sample of Chinese. We studied 165 patients with back disorders and 347 general subjects from China. All subjects had lumbar spine magnetic resonance (MR) imaging and dual- energy X-ray absorptiometry (DXA) spine BMD studies, and a subset of general subjects had additional hip BMD measurements. On T2-weighted MR images, Pfirrmann score was used to evaluate the degree of lumbar disc degeneration and facet joint osteoarthritis was assessed as none, slight-moderate, and severe. Regression analyses were used to examine the associations between lumbar and hip BMD and disc degeneration, adjusting for age, gender, body mass index (BMI), lumbar region, and facet joint osteoarthritis. Greater facet joint osteoarthritis was associated with greater spine BMD (P osteoarthritis entered the regression model, however, greater spine BMD was associated with greater facet joint osteoarthritis (P  0.05). No statistical association was observed between spine BMD and lumbar disc degeneration in patients with back disorders (P > 0.05), and between hip BMD and disc degeneration in general subjects (P > 0.05). BMD may not be a risk factor for lumbar disc degeneration in Chinese. Facet joint osteoarthritis inflates DXA spine BMD measurements and therefore, may confound the association between spine BMD and disc degeneration.

Assessment of trunk muscle density using CT and its association with degenerative disc and facet joint disease of the lumbar spine

International Nuclear Information System (INIS)

Sebro, Ronnie; O'Brien, Liam; Torriani, Martin; Bredella, Miriam A.

2016-01-01

The purpose of this study was (1) to evaluate the association of trunk muscle density assessed by computed tomography (CT) with age, gender, and BMI and (2) to evaluate the association between trunk muscle CT density and degenerative disc and facet joint disease of the lumbar spine. The study was IRB approved and HIPAA compliant. The study group comprised 100 subjects (mean age 44.4 ± 22.2 years, 51 % male) who underwent CT of the abdomen and pelvis without intravenous contrast. Exclusion criteria included prior abdominal or spine surgery, active malignancy and scoliosis. CTs were reviewed and the attenuation of the rectus abdominis, transverse abdominis, internal and external obliques, psoas, multifidus, longissimus and gluteus maximus were measured bilaterally at consistent levels. Degenerative disc and bilateral facet joint disease were scored using established methods. Univariate analyses were performed using linear regression. Multivariate linear regression was performed to adjust for age, gender and BMI. CT density of each trunk muscle correlated inversely with age (p < 0.001) and BMI (p < 0.001). CT density of each trunk muscle correlated inversely with degenerative disc and facet joint disease in the univariate analyses (p < 0.001); however, only the gluteus maximus and the transverse abdominis remained significant predictors of degenerative disc and facet joint disease respectively in the multivariate analysis. Fatty infiltration of trunk musculature increases with age and BMI. Fatty infiltration of the gluteus maximus and transverse abdominis are associated with degenerative disc and facet joint disease, independent of age, gender and BMI. (orig.)

Facet orientation and tropism: associations with spondylolysis.

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Kalichman, Leonid; Guermazi, Ali; Li, Ling; Hunter, David J; Suri, Pradeep

2010-04-01

Cross-sectional study. To evaluate the association between lumbar spine facet joint orientation, facet joint tropism, and spondylolysis identified by multidetector computed tomography (CT) in the community-based Framingham Heart Study. The association between lumbar spondylolysis and facet orientation and tropism remains unclear. This study was an ancillary project to the Framingham Heart Study. Three thousand five hundred twenty-nine participants of the Framingham Heart Study aged 40 to 80 years underwent multidetector CT imaging to assess aortic calcification. One hundred ninety-one subjects were included in this ancillary study. Facet joint features and spondylolysis were evaluated on CT scans. The final analyzed sample included 104 men with mean age 51.90+/-11.25 years and 84 women with mean age 53.61+/-10.20 years. The association between spondylolysis and facet orientation and tropism was examined using univariate and multivariate analyses. Spondylolysis was prevalent in 11.5% of the total population. chi2 test demonstrated a significant sex difference in prevalence of spondylolysis (P=0.0154), with almost 3 times higher prevalence among men. There was no statistically significant difference in facet orientation and continuous facet tropism between individuals with and without spondylolysis at the L5 level (P=0.49 to 0.91). After adjustment for age, sex, and body mass index, no significant association between the occurrence of spondylolysis and facet orientation and tropism was found. In the studied sample the prevalence of facet joint osteoarthritis was significantly higher in individuals with spondylolysis than in those without spondylolysis at both sides of L4-L5 spinal level (P=0.044 at the right side and P=0.003 at the left side) and at left side of L5-S1 level (P=0.038). We did not find an association between facet orientation, facet tropism, and spondylolysis. One of the possible explanations for this is that the high prevalence of facet joint

Treatment of lumbar facet joint syndrome by CT-guided intraarticular infiltration of fact joints; Behandlung des lumbalen Facettensyndroms durch CT-gesteuerte Infiltration der Zwischenwirbelgelenke

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Schleifer, J. [Knappschaftsklinik Puettlingen/Saar (Germany). Orthopaedische Abteilung; Fenzl, G. [Knappschaftsklinik Puettlingen/Saar (Germany). Orthopaedische Abteilung; Wolf, A. [Knappschaftsklinik Puettlingen/Saar (Germany). Radiologische Abteilung; Diehl, K. [Knappschaftsklinik Puettlingen/Saar (Germany). Radiologische Abteilung

1994-11-01

In 62 patients with facet syndrome a total of 205 joints were infiltrated, CT monitoring being used in all cases. Each facet joint was infiltrated with 0.3 ml bupivacaine and 0.8 ml methylprednisolone. The patients were divided into three groups. Group 1 consisted of 24 persons who had undergone lumbar disc surgery, group 2 of 23 patients with spondylarthrosis of the facet joints, and group 3 of 15 patients who had undergone lumbar disc surgery but hat additional spondylarthrosis. Very good results were defined as pain relief for longer than 4 weeks, good results as pain relief for up to 4 weeks and poor results as brief pain relief or none at all. In 27 patients facet infiltration was performed for the purpose of diagnosis. Results were significantly in group 2 than in group 1. In group 3 results were better than in group 1, but worse than in group 2. These differences were not statistical by significant. Seven patients in the diagnostic group had no pain relief, and facet syndrome was excluded. (orig.) [Deutsch] Bei 62 Patienten mit lumbalem Facettensyndrom wurden insgesamt 205 Zwischenwirbelgelenke (Facettengelenke) perkutan CT-gesteuert infiltriert. Je Gelenk wurden 0,3 ml Bupivacain und 0,8 ml Methylprednisolon intraartikulaer infiziert. Die Patienten wurden in 3 Gruppen unterteilt. Die 1. Gruppe umfasste 24 Patienten mit Postnukleotomiesyndrom, die 2. Gruppe 23 Patienten mit spondylarthrotischen Veraenderungen, die 3. Gruppe 15 bandscheibenoperierte Patienten mit zusaetzlicher Spondylarthrose. In Gruppe 2 fanden sich signifikant bessere Ergebnisse als in Gruppe 1. Gute Resultate ergab auch die dritte Gruppe, sie waren jedoch nicht signifikant besser als die der Gruppe 1. Die sorgfaeltige Auswahl der Patienten ist fuer den Erfolg der Behandlung entscheidend. Die Infiltrationsbehandlung der Zwischenwirbelgelenke hat nahezu keine Nebenwirkungen. Ausser zur Therapie wird das Verfahren diagnostisch zum Ausschluss eines Facettensyndromes im Rahmen der Abklaerung

Osseous associated cervical spondylomyelopathy at the C2-C3 articular facet joint in 11 dogs.

Science.gov (United States)

Cooper, C; Gutierrez-Quintana, R; Penderis, J; Gonçalves, R

2015-11-21

In dogs, vertebral canal stenosis at C2-C3 due to articular facet joint degeneration is only sporadically identified. The authors' aims were to review the clinical presentation, MRI characteristics, treatment and outcome of dogs presenting with this condition. Eleven cases were eligible for inclusion. Neurological examination revealed tetraparesis and proprioceptive ataxia in all 4 limbs in 3/11, proprioceptive tetra-ataxia only in 4/11, pelvic limb proprioceptive ataxia in 2/11 and no gait abnormalities in 2/11 dogs. Cervical hyperaesthesia was present in 7/11 dogs. MRI revealed bilateral articular facet joint degeneration in 10/11 cases and unilateral degeneration in one. Surgery was performed in six cases and medical management elected in five. Long-term follow-up information was available for 11 animals. Four of the surgical cases are alive and have no neurological deficits, one was euthanased for an unrelated condition and one lost to follow-up. Of the cases managed medically, three are alive showing no neurological deficits, one is alive still displaying neurological deficits and one euthanased for an unrelated condition whilst still ataxic. This study shows that both medical and surgical management can result in good outcomes in dogs with vertebral canal stenosis resulting from articular facet joint degeneration at the level of C2-C3. British Veterinary Association.

Systematic review of patient history and physical examination to diagnose chronic low back pain originating from the facet joints.

Science.gov (United States)

Maas, E T; Juch, J N S; Ostelo, R W J G; Groeneweg, J G; Kallewaard, J W; Koes, B W; Verhagen, A P; Huygen, F J P M; van Tulder, M W

2017-03-01

Patient history and physical examination are frequently used procedures to diagnose chronic low back pain (CLBP) originating from the facet joints, although the diagnostic accuracy is controversial. The aim of this systematic review is to determine the diagnostic accuracy of patient history and/or physical examination to identify CLBP originating from the facet joints using diagnostic blocks as reference standard. We searched MEDLINE, EMBASE, CINAHL, Web of Science and the Cochrane Collaboration database from inception until June 2016. Two review authors independently selected studies for inclusion, extracted data and assessed the risk of bias. We calculated sensitivity and specificity values, with 95% confidence intervals (95% CI). Twelve studies were included, in which 129 combinations of index tests and reference standards were presented. Most of these index tests have only been evaluated in single studies with a high risk of bias. Four studies evaluated the diagnostic accuracy of the Revel's criteria combination. Because of the clinical heterogeneity, results were not pooled. The published sensitivities ranged from 0.11 (95% CI 0.02-0.29) to 1.00 (95% CI 0.75-1.00), and the specificities ranged from 0.66 (95% CI 0.46-0.82) to 0.91 (95% CI 0.83-0.96). Due to clinical heterogeneity, the evidence for the diagnostic accuracy of patient history and/or physical examination to identify facet joint pain is inconclusive. Patient history and physical examination cannot be used to limit the need of a diagnostic block. The validity of the diagnostic facet joint block should be studied, and high quality studies are required to confirm the results of single studies. Patient history and physical examination cannot be used to limit the need of a diagnostic block. The validity of the diagnostic facet joint block should be studied, and high quality studies are required to confirm the results of single studies. © 2016 European Pain Federation - EFIC®.

Management of low back pain with facet joint injections and nerve root blocks under computed tomography guidance. A prospective study

International Nuclear Information System (INIS)

Fotiadou, Anastasia; Wojcik, Andrew; Shaju, Antony

2012-01-01

The aim of this work was to assess the performance of facet joint and nerve root infiltrations under computed tomography guidance for the management of low back pain and to investigate the complications and patient tolerance. The study was board-certified and informed consent was obtained from all patients. In 1 year, 86 consecutive patients (47 male, 39 female, age range 47-87 years, mean age 63) with low back pain for more than 2 years were included. All patients were clinically examined and had cross-sectional imaging performed before the procedure. Fifty-five facet joint infiltrations and 31 nerve blocks were performed under computed tomography guidance. All patients completed two valid pain questionnaires before and 3 months after the procedures. At the same time, they were clinically examined by the referring Orthopaedic Surgeon. The pain response was assessed by comparing the scores of the questionnaires. The improvement in clinical examination findings was assessed as well. In patients who underwent facet joint infiltrations, long-term pain improvement was achieved in 79% and in those with nerve blocks in 85%. Immediate pain relief was demonstrated in 83% of patients with nerve infiltrations. No complications were observed. All procedures were very well tolerated by patients. Facet joint and nerve infiltrations under computed tomography guidance constitute an accurate and safe method that could be used to relieve low back pain and minimize the risk of disability. (orig.)

Lumbar Facet Joint Compressive Injury Induces Lasting Changes in Local Structure, Nociceptive Scores, and Inflammatory Mediators in a Novel Rat Model

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James L. Henry

2012-01-01

Full Text Available Objective. To develop a novel animal model of persisting lumbar facet joint pain. Methods. Sprague Dawley rats were anaesthetized and the right lumbar (L5/L6 facet joint was exposed and compressed to ~1 mm with modified clamps applied for three minutes; sham-operated and naïve animals were used as control groups. After five days, animals were tested for hind-paw sensitivity using von Frey filaments and axial deep tissue sensitivity by algometer on assigned days up to 28 days. Animals were sacrificed at selected times for histological and biochemical analysis. Results. Histological sections revealed site-specific loss of cartilage in model animals only. Tactile hypersensitivity was observed for the ipsi- and contralateral paws lasting 28 days. The threshold at which deep tissue pressure just elicited vocalization was obtained at three lumbar levels; sensitivity at L1>L3/4>L6. Biochemical analyses revealed increases in proinflammatory cytokines, especially TNF-α, IL-1α, and IL-1β. Conclusions. These data suggest that compression of a facet joint induces a novel model of local cartilage loss accompanied by increased sensitivity to mechanical stimuli and by increases in inflammatory mediators. This new model may be useful for studies on mechanisms and treatment of lumbar facet joint pain and osteoarthritis.

The clinical aspects of the acute facet syndrome

DEFF Research Database (Denmark)

Hestbaek, Lise; Kongsted, Alice; Jensen, Tue Secher

2009-01-01

ABSTRACT: BACKGROUND: The term 'acute facet syndrome' is widely used and accepted amongst chiropractors, but poorly described in the literature, as most of the present literature relates to chronic facet joint pain. Therefore, research into the degree of consensus on the subject amongst a large g...... from the facet joints has been described in the literature. Furthermore, the acute, uncomplicated facet syndrome was considered to have an uncomplicated clinical course, responding quickly to spinal manipulative therapy....

Evaluation of Facet Joint Arthrosis in Stenotic and Normal Lumbar Spines with MRI

Directory of Open Access Journals (Sweden)

Ebru Ozan

2013-10-01

Full Text Available Aim: To reveal the prevalence of lumbar facet joint arthrosis in normal and stenotic lumbar spines with magnetic resonance imaging. Material and Method: Study group consisted of 30 patients with complaints and findings of lower back pain, neurologic claudicatio and lumbar spinal stenosis detected at L3-4, L4-5 and/or L5-S1 with magnetic resonance imaging (cross section area of the dural sac

FacetGist: Collective Extraction of Document Facets in Large Technical Corpora.

Science.gov (United States)

Siddiqui, Tarique; Ren, Xiang; Parameswaran, Aditya; Han, Jiawei

2016-10-01

Given the large volume of technical documents available, it is crucial to automatically organize and categorize these documents to be able to understand and extract value from them. Towards this end, we introduce a new research problem called Facet Extraction. Given a collection of technical documents, the goal of Facet Extraction is to automatically label each document with a set of concepts for the key facets ( e.g. , application, technique, evaluation metrics, and dataset) that people may be interested in. Facet Extraction has numerous applications, including document summarization, literature search, patent search and business intelligence. The major challenge in performing Facet Extraction arises from multiple sources: concept extraction, concept to facet matching, and facet disambiguation. To tackle these challenges, we develop FacetGist, a framework for facet extraction. Facet Extraction involves constructing a graph-based heterogeneous network to capture information available across multiple local sentence-level features, as well as global context features. We then formulate a joint optimization problem, and propose an efficient algorithm for graph-based label propagation to estimate the facet of each concept mention. Experimental results on technical corpora from two domains demonstrate that Facet Extraction can lead to an improvement of over 25% in both precision and recall over competing schemes.

Direct Posterior Bipolar Cervical Facet Radiofrequency Rhizotomy: A Simpler and Safer Approach to Denervate the Facet Capsule.

Science.gov (United States)

Palea, Ovidiu; Andar, Haroon M; Lugo, Ramon; Granville, Michelle; Jacobson, Robert E

2018-03-14

Radiofrequency cervical rhizotomy has been shown to be effective for the relief of chronic neck pain, whether it be due to soft tissue injury, cervical spondylosis, or post-cervical spine surgery. The target and technique have traditionally been taught using an oblique approach to the anterior lateral capsule of the cervical facet joint. The goal is to position the electrode at the proximal location of the recurrent branch after it leaves the exiting nerve root and loops back to the cervical facet joint. The standard oblique approach to the recurrent nerve requires the testing of both motor and sensory components to verify the correct position and ensure safety so as to not damage the slightly more anterior nerve root. Bilateral lesions require the repositioning of the patient's neck. Poorly positioned electrodes can also pass anteriorly and contact the nerve root or vertebral artery. The direct posterior approach presented allows electrode positioning over a broader expanse of the facet joint without risk to the nerve root or vertebral artery. Over a four-year period, direct posterior radiofrequency ablation was performed under fluoroscopic guidance at multiple levels without neuro-stimulation testing with zero procedural neurologic events even as high as the C2 spinal segment. The direct posterior approach allows either unipolar or bipolar lesioning at multiple levels. Making a radiofrequency lesion along the larger posterior area of the facet capsule is as effective as the traditional target point closer to the nerve root but technically easier, allowing bilateral access and safety. The article will review the anatomy and innervation of the cervical facet joint and capsule, showing the diffuse nerve supply extending into the capsule of the facet joint that is more extensive than the recurrent medial sensory branches that have been the focus of radiofrequency lesioning.

A critical evaluation of subtalar joint arthrosis associated with middle facet talocalcaneal coalition in 21 surgically managed patients: a retrospective computed tomography review. Investigations involving middle facet coalitions-part III.

Science.gov (United States)

Kernbach, Klaus J; Barkan, Howard; Blitz, Neal M

2010-01-01

Symptomatic middle facet talocalcaneal coalition is frequently associated with rearfoot arthrosis that is often managed surgically with rearfoot fusion. However, no objective method for classifying the extent of subtalar joint arthrosis exists. No study has clearly identified the extent of posterior facet arthrosis present in a large cohort treated surgically for talocalcaneal coalition through preoperative computerized axial tomography. The authors conducted a retrospective review of 21 patients (35 feet) with coalition who were surgically treated over a 12-year period for coalition on at least 1 foot. Using a predefined original staging system, the extent of the arthrosis was categorized into normal or mild (Stage I), moderate (Stage II), and severe (Stage III) arthrosis. The association of stage and age is statistically significant. All of the feet with Stage III arthrosis had fibrous coalitions. No foot with osseous coalition had Stage III arthrosis. The distribution of arthrosis staging differs between fibrous and osseous coalitions. Only fibrous coalitions had the most advanced arthrosis (Stage III), whereas osseous coalitions did not. This suggests that osseous coalitions may have a protective effect in the prevention of severe degeneration of the subtalar joint. Concomitant subtalar joint arthrosis severity progresses with age; surgeons may want to consider earlier surgical intervention to prevent arthrosis progression in patients with symptomatic middle facet talocalcaneal coalition.

Value of 18F-FDG PET/MRI for the outcome of CT-guided facet block therapy in cervical facet syndrome: initial results

International Nuclear Information System (INIS)

Sawixki, Lino M.; Schaarscjmidt, Benedikt M.; Heusch, Philipp; Buchbender, Christian; Antoch, Gerald; Rosenbaum-Krumme, Sandra; Bockisch, Andreas; Umutlu, Lale; Eicker, Sven O.; Floeth, Frank W.

2017-01-01

The aim of this study was to evaluate the ability of 18 F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging ( 18 F-FDG PET/MRI) to detect PET-positive cervical facet arthropathy and identify patients who benefit from facet block therapy. Ten patients with cervical facet syndrome (mean age: 65 ± 12 years) underwent 18 F-FDG PET/MRI of the neck. Focal 18 F-FDG uptake in PET-positive facet joints served as target for computed tomography (CT)-guided facet blocks. In PET-negative patients, the target joint for facet block therapy was selected by current clinical standards considering the level of maximum facet arthrosis and pain. Neck pain was measured on visual analogue scale (VAS) before and after therapy. Bone marrow signal intensity (SI) ratio on turbo inversion recovery magnitude (TIRM) images and maximum standard uptake values (SUVmax) was calculated for each facet joint. Pearson's correlation coefficient (r) was calculated between bone marrow SI ratios on TIRM and SUVmax. 18 F-FDG PET/MRI detected PET-positive facet arthropathy in six patients. Patients with PET-positive facet arthropathy had significantly less pain compared with the pretreatment pain 3 h (P = 0.002), 4 weeks (P = 0.002) and 3 months (P = 0.026) after facet block therapy. Pain did not change significantly in patients with PET-negative facet arthropathy. TIRM SI ratio was higher in PET-positive facet arthropathy than in PET-negative facet arthropathy (P < 0.001). Correlation was strong between bone marrow SI ratio on TIRM images and SUVmax (r = 0.7; P < 0.001).

Cervical Facet Joint Infection and Associated Epidural Abscess with Streptococcus intermedius from a Dental Infection Origin A Case Report and Review.

Science.gov (United States)

Kaye, Ian David; Protopsaltis, Themistocles S

2016-09-01

Pyogenic cervical facet joint infections are rare and such infections from a dental origin are even less common. Of these few cases, none have described infection with Streptococcus intermedius as the pathogen. A 65-year-old orthopaedic surgeon complained of fevers, right-sided radiating neck pain, stiffness, swelling, erythema, and right upper extremity weakness one month after he had broken a crown over his right mandibular premolar, a continued source of pain. Imaging of the cervical spine showed a right C4-C5 facet inflammatory arthropathy and a small epidural abscess that was cultured and initially treated with intravenous antibiotics. The oral maxillofacial surgery team performed an extraction of the infected, symptomatic tooth. For continued right upper extremity weakness, the patient underwent C4-C5 laminoforaminotomy and irrigation and debridement of the right C4-C5 facet joint. After 6 weeks of intravenous antibiotics, the patient's infectious and inflammatory markers had normalized. By 4 months, he had regained full strength at his upper extremity and a painless and full range of motion of his cervical spine.Pyogenic cervical facet joint infection is very rare and potentially dangerous. A high clinical suspicion and appropriate imaging, including magnetic resonance imaging, are important for correct diagnosis. Prompt medical and surgical treatment may avert complications, and although the patient presented made a complete recovery, patients may be left with neurological compromise.

Septic arthritis of a lumbar facet joint: Detection with bone SPECT imaging

International Nuclear Information System (INIS)

Swayne, L.C.; Dorsky, S.; Caruana, V.; Kaplan, I.L.

1989-01-01

We present a rare case of septic arthritis of a lumbar facet joint with an associated epidural abscess resulting from Staphylococcus aureus. The infection was initially detected with planar bone scintigraphy and precisely localized with single photon emission computed tomography bone scintigraphy, despite an initially negative radiologic evaluation that included radiographs of the lumbar spine, lumbar myelography, and a postmyelography x-ray computed tomography scan. In the appropriate clinical setting, a bone scan demonstrating unilateral increased activity within the spine should raise the suspicion of inflammatory involvement of the posterior elements

Pseudomeningocele in communication with the facet joint: demonstration by computerized tomography-arthrography

International Nuclear Information System (INIS)

Ganiyusufoglu, Kursat; Ozturk, Cagatay; Sirvanci, Mustafa; Aksu, Neslihan; Hamzaoglu, Azmi

2008-01-01

Pseudomeningocele is an uncommon but well-known complication of lumbar spine operations. Although it is mostly asymptomatic and managed conservatively in most cases, it is claimed as a causative factor of failed back surgery syndrome and requires surgery in some cases. Usually, its diagnosis is confidently done with imaging modalities such as magnetic resonance imaging, computed tomography and myelography. In this report, we describe a case of pseudomeningocele that communicated with a facet joint. The diagnostic approach for this unusual lesion and its probable causes are discussed. (orig.)

Pseudomeningocele in communication with the facet joint: demonstration by computerized tomography-arthrography

Energy Technology Data Exchange (ETDEWEB)

Ganiyusufoglu, Kursat; Ozturk, Cagatay; Sirvanci, Mustafa; Aksu, Neslihan; Hamzaoglu, Azmi [Florence Nightingale Hospital, Istanbul Bilim University, Istanbul Spine Center, Istanbul (Turkey)

2008-08-15

Pseudomeningocele is an uncommon but well-known complication of lumbar spine operations. Although it is mostly asymptomatic and managed conservatively in most cases, it is claimed as a causative factor of failed back surgery syndrome and requires surgery in some cases. Usually, its diagnosis is confidently done with imaging modalities such as magnetic resonance imaging, computed tomography and myelography. In this report, we describe a case of pseudomeningocele that communicated with a facet joint. The diagnostic approach for this unusual lesion and its probable causes are discussed. (orig.)

Bending stresses in Facetted Glass Shells

DEFF Research Database (Denmark)

Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik

2008-01-01

A shell structure of glass combines a highly effective structural principle with a material of optimal permeability to light. A facetted shell structure has a piecewise plane geometry, and together the facets form an approximation to a curved surface. A distributed load on a plane-based facetted...... structure will locally cause bending moments in the loaded facets. The bending stresses are dependent on the stiffness of the joints. Approximate solutions are developed to estimate the magnitude of the bending stresses. A FE-model of a facetted glass shell structure is used to validate the expressions...

Biomechanical analysis of press-extension technique on degenerative lumbar with disc herniation and staggered facet joint

Directory of Open Access Journals (Sweden)

Hong-gen Du

2016-05-01

Full Text Available This study investigates the effect of a new Chinese massage technique named “press-extension” on degenerative lumbar with disc herniation and facet joint dislocation, and provides a biomechanical explanation of this massage technique. Self-developed biomechanical software was used to establish a normal L1–S1 lumbar 3D FE model, which integrated the spine CT and MRI data-based anatomical structure. Then graphic technique is utilized to build a degenerative lumbar FE model with disc herniation and facet joint dislocation. According to the actual press-extension experiments, mechanic parameters are collected to set boundary condition for FE analysis. The result demonstrated that press-extension techniques bring the annuli fibrosi obvious induction effect, making the central nucleus pulposus forward close, increasing the pressure in front part. Study concludes that finite element modelling for lumbar spine is suitable for the analysis of press-extension technique impact on lumbar intervertebral disc biomechanics, to provide the basis for the disease mechanism of intervertebral disc herniation using press-extension technique.

Lumbar facet joint septic arthritis presenting atypically as acute abdomen – A case report and review of the literature

Directory of Open Access Journals (Sweden)

Aysha Rajeev

2016-01-01

Conclusion: The atypical presentation of facet joint septic arthritis is one of the reasons why early diagnosis is elusive. Definitive diagnoses with MRI and bacterial culture as well as prolonged antibiotic therapy are recommended in this condition.

MRI-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis low back pain - case series of an innovative new technique

Energy Technology Data Exchange (ETDEWEB)

Weeks, Evan M.; Platt, Michael W. [St Mary' s Hospital, Imperial College Healthcare NHS Trust, Department of Anaesthesia and Pain Medicine, London (United Kingdom); Gedroyc, Wladyslaw [St Mary' s Hospital, Imperial College Healthcare NHS Trust, Department of Radiology, London (United Kingdom)

2012-12-15

To evaluate the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis pain. Patients with a positive response to facet joint interventions were recruited from Pain and Spinal Clinics. Treatments were performed at the levels of pain according to symptomatology, previous invasive treatment and MRI grading of facet joint osteoarthritis. Both safety and efficacy data were collected. Pain palliation was evaluated using a validated pain numerical rating scale (NRS), Oswestry disability questionnaire (ODQ), Brief Pain Inventory (BPI) and the EuroQol (EQ-5D) health state score Eighteen patients were treated. There were no major adverse events. At 6/12 we found a reduction in both the NRS (average/worst) pain scores (60.2 %/51.2 %). This was associated with 45.9 % improvement in the ODQ score and 61.9 % reduction in the BPI interference score. We observed an improvement in the EuroQol (EQ-5D) health state score based on UK coefficients of +0.379 (0.317 to 0.696). Our phase I observational pilot study has evaluated an innovative new technique that is both non-invasive and radiation free. It is the first description of this procedure in the literature. In all patients the technique was safe, free of complications, effective and well tolerated. (orig.)

MRI-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis low back pain - case series of an innovative new technique

International Nuclear Information System (INIS)

Weeks, Evan M.; Platt, Michael W.; Gedroyc, Wladyslaw

2012-01-01

To evaluate the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis pain. Patients with a positive response to facet joint interventions were recruited from Pain and Spinal Clinics. Treatments were performed at the levels of pain according to symptomatology, previous invasive treatment and MRI grading of facet joint osteoarthritis. Both safety and efficacy data were collected. Pain palliation was evaluated using a validated pain numerical rating scale (NRS), Oswestry disability questionnaire (ODQ), Brief Pain Inventory (BPI) and the EuroQol (EQ-5D) health state score Eighteen patients were treated. There were no major adverse events. At 6/12 we found a reduction in both the NRS (average/worst) pain scores (60.2 %/51.2 %). This was associated with 45.9 % improvement in the ODQ score and 61.9 % reduction in the BPI interference score. We observed an improvement in the EuroQol (EQ-5D) health state score based on UK coefficients of +0.379 (0.317 to 0.696). Our phase I observational pilot study has evaluated an innovative new technique that is both non-invasive and radiation free. It is the first description of this procedure in the literature. In all patients the technique was safe, free of complications, effective and well tolerated. (orig.)

Unusual case of paediatric septic arthritis of the lumbar facet joints due to Kingella kingae.

Science.gov (United States)

Le Hanneur, M; Vidal, C; Mallet, C; Mazda, K; Ilharreborde, B

2016-11-01

A 32-month-old boy presented with febrile limping that had developed over 6days, associated with right lumbosacral inflammatory swelling. Magnetic resonance imaging (MRI) showed joint effusion of the right L5-S1 zygapophyseal joint, complicated by destructive osteomyelitis of the L5 articular process and paraspinal abscess. Surgery was decided to evacuate the fluid accumulation and rule out differential diagnoses. The diagnosis of septic arthritis of the facet joint was confirmed intraoperatively; real-time quantitative PCR analysis identified Kingella kingae. This is the first substantiated paediatric case of zygapophyseal joint septic arthritis due to K. kingae. K. kingae is the most common pathogen responsible for invasive osteoarticular infection in children under 4years of age. Since empiric antibiotics are effective in early stages, physicians should consider the possibility of spinal infections due to K. kingae when a limping child under 4years of age presents with a fever. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Increasing Running Step Rate Reduces Patellofemoral Joint Forces

Science.gov (United States)

Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

2013-01-01

Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

Isolated septic facet joint arthritis as a rare cause of acute and chronic low back pain – a case report and literature review

International Nuclear Information System (INIS)

Klekot, Dominika; Zimny, Anna; Czapiga, Bogdan; Sąsiadek, Marek

2012-01-01

The most common cause of low back pain is degenerative disease of the intervertebral disc and other structures of the lumbar spine. However, in some cases other less frequent causes of such pain can be seen, for example septic facet joint arthritis. Until now, only 40 cases of such inflammatory changes within the spine have been reported in the literature. The disease is probably underestimated due to improper diagnostic pathway. The authors describe a case of a 53-year-old woman who was repeatedly hospitalized during a five-month period because of an acute, severe low back pain, with sphincter dysfunction, partially resembling sciatic symptoms. Physical examinations revealed also focal tenderness in the area of the lumbar spine. Inflammatory markers (ESR – erythrocyte sedimentation rate, CRP – C-reactive protein) were elevated. Conservative analgetic treatment brought only partial and temporary relief of the pain and symptoms. The final accurate diagnosis of isolated septic facet joint arthritis at the level of L5/S1 was established after several months from the onset of the first symptoms, after performing various imaging examinations, including bone scintigraphy as well as CT and MRI of the lumbosacral spine. The patient fully recovered after antibiotic therapy and surgery, which was proven in several follow-up examinations showing no relevant pathology of the lumbar spine. The authors broadly describe the etiology and clinical symptoms of the septic facet joint arthritis as well as the significant role of imaging methods, especially MRI, in diagnostic process. The authors also discuss currently available treatment options, both conservative and surgical. The diagnostic procedure of septic facet joint arthritis requires several steps to be taken. Establishing a correct diagnosis may be difficult, that is why it is important to remember about rare causes of low back pain and to perform detailed physical examination, laboratory tests and choose appropriate

A nondestructive, reproducible method of measuring joint reaction force at the distal radioulnar joint.

Science.gov (United States)

Canham, Colin D; Schreck, Michael J; Maqsoodi, Noorullah; Doolittle, Madison; Olles, Mark; Elfar, John C

2015-06-01

To develop a nondestructive method of measuring distal radioulnar joint (DRUJ) joint reaction force (JRF) that preserves all periarticular soft tissues and more accurately reflects in vivo conditions. Eight fresh-frozen human cadaveric limbs were obtained. A threaded Steinmann pin was placed in the middle of the lateral side of the distal radius transverse to the DRUJ. A second pin was placed into the middle of the medial side of the distal ulna colinear to the distal radial pin. Specimens were mounted onto a tensile testing machine using a custom fixture. A uniaxial distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Force-displacement curves were generated and a best-fit polynomial was solved to determine JRF. All force-displacement curves demonstrated an initial high slope where relatively large forces were required to distract the joint. This ended with an inflection point followed by a linear area with a low slope, where small increases in force generated larger amounts of distraction. Each sample was measured 3 times and there was high reproducibility between repeated measurements. The average baseline DRUJ JRF was 7.5 N (n = 8). This study describes a reproducible method of measuring DRUJ reaction forces that preserves all periarticular stabilizing structures. This technique of JRF measurement may also be suited for applications in the small joints of the wrist and hand. Changes in JRF can alter native joint mechanics and lead to pathology. Reliable methods of measuring these forces are important for determining how pathology and surgical interventions affect joint biomechanics. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Short-term outcome of fluoroscopic-guided steroid injection therapy of lumber facet cyst-induced radicular pain

Energy Technology Data Exchange (ETDEWEB)

Kwon, Mi Ri; Kwon, Jong Won; Lee, Jong Seo; Kim, Eu Sang [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2015-04-15

To determine the short-term effect of fluoroscopic-guided steroid injection therapy of lumbar facet cyst-induced radicular pain. Seventeen patients with radiculopathy due to lumbar synovial cysts, who were treated with fluoroscopically guided injection, were retrospectively evaluated. All plain radiographic images and MR images before the therapy were reviewed. Five patients underwent only the facet joint injection, whereas twelve patients underwent the facet joint injection with perineural injection therapy. The clinical course of pain was evaluated on the first follow-up after therapy. Effective pain relief was achieved in 11 (64.7%) of the 17 patients. Among 12 patients who underwent facet joint injection with perineural injection, 9 patients (75%) had an effective pain relief. Of 5 patients, 2 (40%) patients only took the facet joint injection and had an effective pain relief. Fluoroscopic-guided steroid injection therapy shows a good short-term effect in patients with symptomatic lumbar facet joint synovial cysts.

Lumbar Facet Joint Arthritis Is Associated with More Coronal Orientation of the Facet Joints at the Upper Lumbar Spine

International Nuclear Information System (INIS)

Jentzsch, Th.; Geiger, J.; Zimmermann, S.M.; Slankamenac, K.; Werner, C.M.L.; Nguyen-Kim, Th.D.L.

2013-01-01

We retrospectively analyzed CT scans of 620 individuals, who presented to our traumatology department between 2008 and 2010. Facet joint (FJ) arthritis was present in 308 (49.7%) individuals with a mean grade of 1. It was seen in 27% of individuals ≤40 years and in 75% of individuals ≥41 years ( Ρ <0.0001) as well as in 52% of females and 49% of males ( Ρ=0.61). Mean FJ orientation was 30.4° at L2/3, 38.7° at L3/4, 47° at L4/5, and 47.3° at L5/S1. FJ arthritis was significantly associated with more coronal (increased degree) FJ orientation at L2/3 (Ρ=0.03) with a cutoff point at ≥32°. FJs were more coronally oriented (48.8°) in individuals ≤40 years and more sagittally oriented (45.6°) in individuals ≥41 years at L5/S1 (Ρ=0.01). Mean FJ asymmetry was 4.89° at L2/3, 6.01° at L3/4, 6.67° at L4/5, and 7.27° at L5/S1, without a significant difference for FJ arthritis. FJ arthritis is common, increases with age, and affects both genders equally. More coronally oriented FJs (≥32°) in the upper lumbar spine may be an individual risk factor for development of FJ arthritis.

Joint Force Quarterly. Number 4, Spring 1994

Science.gov (United States)

1994-05-01

Martin J. Peters, Jr. Calvin B. Kelley Art Direction Typography and Design Division Government Printing Office Joint Force Quarterly is published by...within larger organizations. For example, the concept 6 JFQ / Spring 1994 of the combined joint task force for Europe is designed to provide just such...or financial, may be the shared outcome for all parties to future conflicts. The image of war, shaped over centuries, is precise, graphic , and

The lumbar facet arthrosis syndrome. Clinical presentation and articular surface changes.

Science.gov (United States)

Eisenstein, S M; Parry, C R

1987-01-01

We describe a lumbar facet syndrome in which disabling symptoms are associated with normal or near-normal plain radiographs. Local spinal fusion relieved symptoms in 12 patients; the excised facet joint surfaces showed some of the histological changes seen in chondromalacia patellae and in osteoarthritis of other large joints. The most frequent change was focal full-thickness cartilage necrosis or loss of cartilage with exposure of subchondral bone, but osteophyte formation was remarkably absent in all specimens. We suggest that there are both clinical and histological similarities between the facet arthrosis syndrome and chondromalacia patellae. Facet arthrosis may be a relatively important cause of intractable back pain in young and middle-aged adults.

THERAPEUTIC EFFECTIVENESS OF THORACIC FACET JOINT INTERVENTIONS IN CHRONIC THORACIC PAIN%X光引导胸椎小关节注射治疗胸背痛的疗效观察

Institute of Scientific and Technical Information of China (English)

李晓宏; 李世杰; 黄翔; 富沛勇; 杨承祥

2013-01-01

目的:评价小关节注射治疗胸背部疼痛的临床疗效及安全性.方法:60例经保守治疗无效的慢性胸背痛患者,随机分为超激光治疗组(S组,n=30)和介入治疗组(Ⅰ组,n=30).S组患者取俯卧位,超激光照射病变关节部位,每天1次,每次15 rain,共14次；Ⅰ组患者取俯卧位,在X光引导下确定病变小关节平面,穿刺针经皮正确无误到达胸椎后关节突关节间隙,到位后注射消炎镇痛液.对治疗后第1周、2周、1个月、3个月的VAS进行评分、生活质量改善情况及安全性进行评估.结果:与S组比较,Ⅰ组治疗患者术后3个月的VAS评分较治疗前有显著性降低(P＜0.05),且未发现有严重并发症.结论:小关节注射治疗胸背痛是一项操作简便、安全,疗效确切、可靠的微创介入治疗方法.%Objective:To determine the clinical effectiveness of zygapophysial joint injections with fluoroscopy in managing chronic mid back or upper back pain of facet joint origin.Methods:A total of 60 patients were randomized divided into two groups,with 30 patients in each of the super laser and facet joint interventions groups.All of the patients met the diagnostic criteria of thoracic facet joint pain by means of the inclusion criteria.Group S patients received thoracic facet joint with super laser,whereas Group Ⅰ patients received thoracic facet joint intervention with bupivacaine and non-particulate betamethasone.The clinical efficacy were assessed by patients with visual analogue scale(VAS).All outcomes were assessed at baseline,1 week,2 weeks,1 month,and 3 months after treatment.Results:In Group S,compared with baseline,patients showed significant pain relief and functional improvement at 1 week (P ＜ 0.05) But there were no significant pain relief after 2 weeks.In Group Ⅰ,patients showed significant pain relief and functional improvement after facet joint injection,a significant change 3 months after treatment from baseline (P ＜ 0

Elastic moduli of faceted aluminum nitride nanotubes measured by contact resonance atomic force microscopy

International Nuclear Information System (INIS)

Stan, G; Cook, R F; Ciobanu, C V; Thayer, T P; Wang, G T; Creighton, J R; Purushotham, K P; Bendersky, L A

2009-01-01

A new methodology for determining the radial elastic modulus of a one-dimensional nanostructure laid on a substrate has been developed. The methodology consists of the combination of contact resonance atomic force microscopy (AFM) with finite element analysis, and we illustrate it for the case of faceted AlN nanotubes with triangular cross-sections. By making precision measurements of the resonance frequencies of the AFM cantilever-probe first in air and then in contact with the AlN nanotubes, we determine the contact stiffness at different locations on the nanotubes, i.e. on edges, inner surfaces, and outer facets. From the contact stiffness we have extracted the indentation modulus and found that this modulus depends strongly on the apex angle of the nanotube, varying from 250 to 400 GPa for indentation on the edges of the nanotubes investigated.

The efficacy of conventional radiofrequency denervation in patients with chronic low back pain originating from the facet joints: a meta-analysis of randomized controlled trials.

Science.gov (United States)

Lee, Chang-Hyun; Chung, Chun Kee; Kim, Chi Heon

2017-11-01

Radiofrequency denervation is commonly used for the treatment of chronic facet joint pain that has been refractory to more conservative treatments, although the evidence supporting this treatment has been controversial. We aimed to elucidate the precise effects of radiofrequency denervation in patients with low back pain originating from the facet joints relative to those obtained using control treatments, with particular attention to consistency in the denervation protocol. A meta-analysis of randomized controlled trials was carried out. Adult patients undergoing radiofrequency denervation or control treatments (sham or epidural block) for facet joint disease of the lumbar spine comprised the patient sample. Visual analog scale (VAS) pain scores were measured and stratified by response of diagnostic block procedures. We searched PubMed, Embase, Web of Science, and the Cochrane Database for randomized controlled trials regarding radiofrequency denervation and control treatments for back pain. Changes in VAS pain scores of the radiofrequency group were compared with those of the control group as well as the minimal clinically important difference (MCID) for back pain VAS. Meta-regression model was developed to evaluate the effect of radiofrequency treatment according to responses of diagnostic block while controlling for other variables. We then calculated mean differences and 95% confidence intervals (CIs) using random-effects models. We included data from seven trials involving 454 patients who had undergone radiofrequency denervation (231 patients) and control treatments such as sham or epidural block procedures (223 patients). The radiofrequency group exhibited significantly greater improvements in back pain score when compared with the control group for 1-year follow-up. Although the average improvement in VAS scores exceeded the MCID, the lower limit of the 95% CI encompassed the MCID. A subgroup of patients who responded very well to diagnostic block

Can shoulder joint reaction forces be estimated by neural networks?

NARCIS (Netherlands)

de Vries, W.H.K.; Veeger, H.E.J.; Baten, C.T.M.; van der Helm, F.C.T.

2016-01-01

To facilitate the development of future shoulder endoprostheses, a long term load profile of the shoulder joint is desired. A musculoskeletal model using 3D kinematics and external forces as input can estimate the mechanical load on the glenohumeral joint, in terms of joint reaction forces. For long

Migration mechanisms of a faceted grain boundary

Science.gov (United States)

Hadian, R.; Grabowski, B.; Finnis, M. W.; Neugebauer, J.

2018-04-01

We report molecular dynamics simulations and their analysis for a mixed tilt and twist grain boundary vicinal to the Σ 7 symmetric tilt boundary of the type {1 2 3 } in aluminum. When minimized in energy at 0 K , a grain boundary of this type exhibits nanofacets that contain kinks. We observe that at higher temperatures of migration simulations, given extended annealing times, it is energetically favorable for these nanofacets to coalesce into a large terrace-facet structure. Therefore, we initiate the simulations from such a structure and study as a function of applied driving force and temperature how the boundary migrates. We find the migration of a faceted boundary can be described in terms of the flow of steps. The migration is dominated at lower driving force by the collective motion of the steps incorporated in the facet, and at higher driving forces by the step detachment from the terrace-facet junction and propagation of steps across the terraces. The velocity of steps on terraces is faster than their velocity when incorporated in the facet, and very much faster than the velocity of the facet profile itself, which is almost stationary. A simple kinetic Monte Carlo model matches the broad kinematic features revealed by the molecular dynamics. Since the mechanisms seem likely to be very general on kinked grain-boundary planes, the step-flow description is a promising approach to more quantitative modeling of general grain boundaries.

Imaging by atomic force microscopy of the properties difference of the layers covering the facets created during SIMS analysis

Energy Technology Data Exchange (ETDEWEB)

Fares, B., E-mail: boubker.fares@hotmail.fr [Université Mohammed V-Agdal, Faculté des Sciences, LPM, B.P. 1014 Rabat (Morocco); Gautier, B.; Albertini, D. [Institut des Nanotechnologies de Lyon, UMR CNRS 5511, Université de Lyon, 7 Avenue Capelle, 69621 Villeurbanne (France); Mzerd, A.; Loghmarti, M. [Université Mohammed V-Agdal, Faculté des Sciences, LPM, B.P. 1014 Rabat (Morocco)

2014-07-01

Atomic force microscopy (AFM) is used in tapping mode in order to study the roughness created in the crater bottom during secondary ions mass spectrometry (SIMS) analysis in silicon, using O{sub 2}{sup +} primary ions without flooding. Previous studies of the chemical composition of the facets created during the analysis have lead to the conclusion that the facets oriented toward the O{sub 2}{sup +} beam during the ionic bombardment were close to SiO{sub 2} in composition, while the facets hidden from the beam were covered with a sub-stoichiometric oxide SiO{sub x} (with x < 2). We show that the AFM phase contrast during tapping mode observation of the facets reflects this composition difference, revealing a sharp contrast between the facets. The observed contrast may arise from the different chemical composition of the facets, leading to a different energy dissipation of the tip/sample system over Si and SiO{sub 2} due to the different properties of the materials (hardness, adhesion, etc.). As a comparison, an observation of a surface covered with SiO{sub 2} and Si (SiO{sub 2} deposed with a 90 nm or 4 nm thickness, and partially removed from a Si surface) shows the same kind of contrast.

Randomised sham-controlled double-blind multicentre clinical trial to ascertain the effect of percutaneous radiofrequency treatment for lumbar facet joint pain.

Science.gov (United States)

van Tilburg, C W J; Stronks, D L; Groeneweg, J G; Huygen, F J P M

2016-11-01

The aim of this study was to compare the effect of a percutaneous radiofrequency heat lesion at the medial branch of the primary dorsal ramus with a sham procedure, for the treatment of lumbar facet joint pain. A randomised sham-controlled double blind multicentre trial was carried out at the multidisciplinary pain centres of two hospitals. A total of 60 patients aged > 18 years with a history and physical examination suggestive of facet joint pain and a decrease of ≥ 2 on a numerical rating scale (NRS 0 to 10) after a diagnostic facet joint test block were included. In the treatment group, a percutaneous radiofrequency heat lesion (80 o C during 60 seconds per level) was applied to the medial branch of the primary dorsal ramus. In the sham group, the same procedure was undertaken without for the radiofrequency lesion. Both groups also received a graded activity physiotherapy programme. The primary outcome measure was decrease in pain. A secondary outcome measure was the Global Perceived Effect scale (GPE). There was a statistically significant effect on the level of pain in the factor Period (T0-T1). However, there was no statistically significant difference with the passage of time between the groups (Group × Period) or in the factor Group. In the crossover group, 11 of 19 patients had a decrease in NRS of ≥ 2 at one month crossover (p = 0.65). There was no statistically significant difference in satisfaction with the passage of time between the groups (Group × Period). The independent factors Group and Period also showed no statistically significant difference. There was no statistically significant Group × Period effect for recovery, neither an effect of Group or of Period. The null hypothesis of no difference in the decrease in pain and in GPE between the treatment and sham groups cannot be rejected. Post hoc analysis revealed that the age of the patients and the severity of the initial pain significantly predicted a positive outcome. Cite this article

Joint Force Quarterly. Number 2, Autumn 1993

Science.gov (United States)

1993-09-01

Typography and Design Division Government Printing Office Joint Force Quarterly is published by the Institute for National Strategic Studies, National...Decisions regard- ing the key force will affect many factors in the new environment. It determines reaction time, how much and what type of force to...shelters destroyed? Only indirectly. Attacks on shel- ters had forced a reaction by the Iraqis, one that caused the loss of their air arm as a force in

Techniques of Force and Pressure Measurement in the Small Joints of the Wrist.

Science.gov (United States)

Schreck, Michael J; Kelly, Meghan; Canham, Colin D; Elfar, John C

2018-01-01

The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints. A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces. Methods of biomechanical force measurements in joints are reviewed. Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.

Model Testing of Forces in the Reflector Joint and Mooring Forces on Wave Dragon

DEFF Research Database (Denmark)

Gilling, Lasse; Kofoed, Jens Peter; Tedd, James

This report aims to present the results of a test series analysing the forces in the redesigned reflector joint and the forces in the main mooring link. The resluts presented are intended to be used by WD project partners, for the design and construction of the joint on the prototype Wave Dragon...... at Nissum Bredning and for future North Sea scale Wave Dragon. Lengths, forces and other dimentions presented are scaled to the North sea Wave Dragon unless otherwise specified....

Joint forces and torques when walking in shallow water.

Science.gov (United States)

Orselli, Maria Isabel Veras; Duarte, Marcos

2011-04-07

This study reports for the first time an estimation of the internal net joint forces and torques on adults' lower limbs and pelvis when walking in shallow water, taking into account the drag forces generated by the movement of their bodies in the water and the equivalent data when they walk on land. A force plate and a video camera were used to perform a two-dimensional gait analysis at the sagittal plane of 10 healthy young adults walking at comfortable speeds on land and in water at a chest-high level. We estimated the drag force on each body segment and the joint forces and torques at the ankle, knee, and hip of the right side of their bodies using inverse dynamics. The observed subjects' apparent weight in water was about 35% of their weight on land and they were about 2.7 times slower when walking in water. When the subjects walked in water compared with walking on land, there were no differences in the angular displacements but there was a significant reduction in the joint torques which was related to the water's depth. The greatest reduction was observed for the ankle and then the knee and no reduction was observed for the hip. All joint powers were significantly reduced in water. The compressive and shear joint forces were on average about three times lower during walking in water than on land. These quantitative results substantiate the use of water as a safe environment for practicing low-impact exercises, particularly walking. Copyright © 2011 Elsevier Ltd. All rights reserved.

The constrained control of force and position in multi-joint movements.

Science.gov (United States)

van Ingen Schenau, G J; Boots, P J; de Groot, G; Snackers, R J; van Woensel, W W

1992-01-01

In many arm or leg movements the hand or foot has to exert an external force on the environment. Based on an inverse dynamical analysis of cycling, it is shown that the distribution of net moments in the joints needed to control the direction of the external force is often opposite to the direction of joint displacements associated with this task. Kinetic and kinematic data were obtained from five experienced cyclists during ergometer cycling by means of film analysis and pedal force measurement. An inverse dynamic analysis, based on a linked segments model, yielded net joint moments, joint powers and muscle shortening velocities of eight leg muscles. Activation patterns of the muscles were obtained by means of surface electromyography. The results show that the transfer of rotations in hip, knee and ankle joints into the translation of the pedal is constrained by conflicting requirements. This occurs between the joint moments necessary to contribute to joint power and the moments necessary to establish a direction of the force on the pedal which allows this force to do work on the pedal. Co-activation of mono-articular agonists and their bi-articular antagonists appear to provide a unique solution for these conflicting requirements: bi-articular muscles appear to be able to control the desired direction of the external force on the pedal by adjusting the relative distribution of net moments over the joints while mono-articular muscles appear to be primarily activated when they are in the position to shorten and thus to contribute to positive work. Examples are given to illustrate the universal nature of this constrained control of force (external) and position (joint). Based on this study and published data it is suggested that different processes may underlie the organization of the control of mono- and bi-articular muscles.

The collision forces and lower-extremity inter-joint coordination during running.

Science.gov (United States)

Wang, Li-I; Gu, Chin-Yi; Wang, I-Lin; Siao, Sheng-Wun; Chen, Szu-Ting

2018-06-01

The purpose of this study was to compare the lower extremity inter-joint coordination of different collision forces runners during running braking phase. A dynamical system approach was used to analyse the inter-joint coordination parameters. Data were collected with six infra-red cameras and two force plates. According to the impact peak of the vertical ground reaction force, twenty habitually rearfoot-strike runners were categorised into three groups: high collision forces runners (HF group, n = 8), medium collision forces runners (MF group, n = 5), and low collision forces runners (LF group, n = 7). There were no significant differences among the three groups in the ankle and knee joint angle upon landing and in the running velocity (p > 0.05). The HF group produced significantly smaller deviation phase (DP) of the hip flexion/extension-knee flexion/extension during the braking phase compared with the MF and LF groups (p braking phase correlated negatively with the collision force (p < 0.05). The disparities regarding the flexibility of lower extremity inter-joint coordination were found in high collision forces runners. The efforts of the inter-joint coordination and the risk of running injuries need to be clarified further.

Gradient-echo imaging of intervertebral disk degeneration and facet joint disease

International Nuclear Information System (INIS)

Berns, D.H.; Kormos, D.; Modic, M.T.; Carter, J.; Masaryk, T.J.; Ross, J.S.

1988-01-01

The purpose of this study was to evaluate the accuracy of gradient-echo, partial-flip angle images in the evaluation of components of degenerative spine disease. First, cadaveric spines were studied with plain radiographs, high-resolution CT, T1-weighted spin-echo (SE) MR images (repetition time msec/echo time msec=500/17). T2-weighted SE images (2,000/30-90), and fast low-angle shot (FLASH) images (200/10.50 0 ) before and after intradiskal injection of air (0.1-1cc). Second, lumbar spine MR images were retrospectively evaluated to compare gradient-echo and SE sequences. Results indicate that the signal intensity changes of the intervertebral disk related to degeneration were best appreciated on T2-weighted SE studies in both groups. Vacuum phenomenon and calcification were most accurately assessed with FLASH imaging (based on susceptibility changes) and CT images. SE images appeared more sensitive to adjacent marrow change. In the facet joints, CT was more accurate for changes in the subarticular bone, but FLASH images were more sensitive to change in the articular cartilage

Pain from intra-articular NGF or joint injury in the rat requires contributions from peptidergic joint afferents.

Science.gov (United States)

Kras, Jeffrey V; Weisshaar, Christine L; Pall, Parul S; Winkelstein, Beth A

2015-09-14

Non-physiological stretch of the cervical facet joint's capsular ligament induces persistent behavioral hypersensitivity and spinal neuronal hyperexcitability via an intra-articular NGF-dependent mechanism. Although that ligament is innervated by nociceptors, it is unknown if a subpopulation is exclusively responsible for the behavioral and spinal neuronal responses to intra-articular NGF and/or facet joint injury. This study ablated joint afferents using the neurotoxin saporin targeted to neurons involved in either peptidergic ([Sar(9),Met (O2)(11)]-substance P-saporin (SSP-Sap)) or non-peptidergic (isolectin B4-saporin (IB4-Sap)) signaling to investigate the contributions of those neuronal populations to facet-mediated pain. SSP-Sap, but not IB4-Sap, injected into the bilateral C6/C7 facet joints 14 days prior to an intra- articular NGF injection prevents NGF-induced mechanical and thermal hypersensitivity in the forepaws. Similarly, only SSP- Sap prevents the increase in mechanical forepaw stimulation- induced firing of spinal neurons after intra-articular NGF. In addition, intra-articular SSP-Sap prevents both behavioral hypersensitivity and upregulation of NGF in the dorsal root ganglion after a facet joint distraction that normally induces pain. These findings collectively suggest that disruption of peptidergic signaling within the joint may be a potential treatment for facet pain, as well as other painful joint conditions associated with elevated NGF, such as osteoarthritis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Intra-articular calcaneal fractures: effect of open reduction and internal fixation on the contact characteristics of the subtalar joint.

Science.gov (United States)

Mulcahy, D M; McCormack, D M; Stephens, M M

1998-12-01

Intra-articular calcaneal fractures are associated with significant long-term morbidity, and considerable controversy exists regarding the optimum method of treating them. The contact characteristics in the intact subtalar joint were determined at known loads and for different positions of the ankle and subtalar joint, using pressure-sensitive film (Super Low; Fuji, Itochu Canada Ltd, Montreal, Quebec). We measured the contact area to joint area ratio (pressure > 5 kg force/cm2 [kgf/cm2]) which normalizes for differences in joint size and the ratio of high pressure zone (>20 kgf/cm2) as a reflection of overall increase in joint pressure. Three simulated fracture patterns were then created and stabilized with either 1 or 2 mm of articular incongruity. Eight specimens were prepared with a primary fracture line through the posterior facet, eight with a joint depression-type fracture, and six with a central joint depression fracture. A measure of 1 to 2 mm of incongruity in the posterior facet for all three fracture patterns produced significant unloading of the depressed fragment, with a redistribution of the overall pattern of pressure distribution to parts of the facet that were previously unloaded.

Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces

Science.gov (United States)

Gerus, Pauline; Sartori, Massimo; Besier, Thor F.; Fregly, Benjamin J.; Delp, Scott L.; Banks, Scott A.; Pandy, Marcus G.; D’Lima, Darryl D.; Lloyd, David G.

2013-01-01

Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

Rescuing Joint Personnel Recovery: Using Air Force Capability to Address Joint Shortfalls

Science.gov (United States)

2011-06-01

of an IP, the IP is not successfully reintegrated or the lessons learned are not incorporated into other operations. Adversaries will benefit from...Washington, D.C.: Office of Air Force History , United States Air Force, 1980, 117. 47 Durant , Michael J. In the Company of Heroes, Penguin Group... Lessons Learned, 22 September 2005, 3. 2 US Joint Task Force Katrina. The Federal Response to Hurricane Katrina Lessons Learned, February 2006, 54

Bidirectional transfer between joint and individual actions in a task of discrete force production.

Science.gov (United States)

Masumoto, Junya; Inui, Nobuyuki

2017-07-01

The present study examined bidirectional learning transfer between joint and individual actions involving discrete isometric force production with the right index finger. To examine the effects of practice of joint action on performance of the individual action, participants performed a pre-test (individual condition), practice blocks (joint condition), and a post-test (individual condition) (IJI task). To examine the effects of practice of the individual action on performance during the joint action, the participants performed a pre-test (joint condition), practice blocks (individual condition), and a post-test (joint condition) (JIJ task). Whereas one participant made pressing movements with a target peak force of 10% maximum voluntary contraction (MVC) in the individual condition, two participants produced the target force of the sum of 10% MVC produced by each of them in the joint condition. In both the IJI and JIJ tasks, absolute errors and standard deviations of peak force were smaller post-test than pre-test, indicating bidirectional transfer between individual and joint conditions for force accuracy and variability. Although the negative correlation between forces produced by two participants (complementary force production) became stronger with practice blocks in the IJI task, there was no difference between the pre- and post-tests for the negative correlation in the JIJ task. In the JIJ task, the decrease in force accuracy and variability during the individual action did not facilitate complementary force production during the joint action. This indicates that practice performed by two people is essential for complementary force production in joint action.

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...

Intraarticular Facet Injections for Low Back Pain: Design Considerations, Consensus Methodology to Develop the Protocol for a Randomized Controlled Trial.

Science.gov (United States)

Mars, Tom; Ellard, David R; Antrobus, James H L; Cairns, Melinda; Underwood, Martin; Haywood, Kirstie; Keohane, Susie; Sandhu, Harbinder; Griffiths, Frances

2015-01-01

Since the publication of guidelines by the UK National Institute for Health and Care Excellence (NICE) and the American Pain Society guidelines for low back pain in 2009 there have been deep divisions in the pain treatment community about the use of therapeutic intraarticular facet joint injections. While evidence for the effectiveness or not of intraarticular facet joint injections remains sparse, uncertainty will remain. The Warwick feasibility study, along with a concurrent study with a different design led by another group, aims to provide a stable platform from which the effectiveness and cost effectiveness of intraarticular facet joint injections added to normal care could be evaluated in randomized controlled trials (RCTs). To reach consensus on key design considerations for the Warwick facet feasibility study from which the study protocol and working manuals will be developed. A consensus conference involving expert professionals and lay members. Preliminary work identified 5 key design considerations for deliberation at our consensus conference. Three concerned patient assessment and treatment: diagnosis of possible facet joint pain, interaarticular facet joint injection technique, and best usual care. Two concerned trial analysis: a priori sub-groups and minimally important difference and are reported elsewhere. We did systematic evidence reviews of the design considerations and summarized the evidence. Our design questions and evidence summaries were distributed to all delegates. This formed the basis for discussions on the day. Clinical experts in all aspects of facet joint injection from across the UK along with lay people were invited via relevant organizations. Nominal group technique was used in 15 facilitated initial small group discussions. Further discussion and ranking was undertaken in plenary. All small group and plenary results were recorded and checked and verified post conference. Where necessary participants were contacted via email to

Neuromuscular adaptations associated with knee joint angle-specific force change.

Science.gov (United States)

Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

2014-08-01

Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

The Multinational Logistics Joint Task Force (MLJTF)

National Research Council Canada - National Science Library

Higginbotham, Matthew T

2007-01-01

In this monograph, by analyzing the UN, NATO and the US Army's evolving Modular Logistics Doctrine, the author integrates the key areas from each doctrine into a multinational logistics joint task force (MLJTF) organization...

Characteristic MRI and MR Myelography Findings for the Facet Cyst Hematoma at T12-L1 Spine: A Case Report

International Nuclear Information System (INIS)

Chung, Seung Eun; Lee, Sang Ho; Kim, Tae Hong; Choi, Gun; Paeng, Sung Suk

2011-01-01

A facet cyst is a very rare condition in the thoracolumbar spine and more so, hemorrhage into a cyst is extremely rare. We present a case of a facet cyst hematoma in the T12-L1 spine. A 69-year-old woman complained of chronic back pain with right lower extremity pain, and weakness for 3 years. MRI and MR myelography showed an extradural mass at the T12-L1 level with heterogeneous signal intensity on both T1-and T2-weighted images, which was continuous to the right T12-L1 facet joint. The neighboring facet joint showed severe degeneration on the CT scan. The mass a was simple hematoma covered with a thin fibrous membrane and connected with facet joint macroscopically and microscopically. The pathogenesis of the facet cyst hematoma is not clear but it can compress nerve roots or dura mater and cause radiculopathy or cauda equina syndrome. Surgical removal should be recommended for symptomatic relief.

Characteristic MRI and MR Myelography Findings for the Facet Cyst Hematoma at T12-L1 Spine: A Case Report

Energy Technology Data Exchange (ETDEWEB)

Chung, Seung Eun [Dept of Diagnostic Radiology, Wooridul Spine Hospital, Seoul (Korea, Republic of); Lee, Sang Ho [Dept. of Neurosurgery, Wooridul Spine Hospital, Seoul (Korea, Republic of); Kim, Tae Hong [Dept. of Neurosurgery, Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of); Choi, Gun [Dept. of Neurosurgery, Seoul Wooridul Hospital, Seoul (Korea, Republic of); Paeng, Sung Suk [Dept of Radiology, Wooridul Spine Hospital, Seoul (Korea, Republic of)

2011-05-15

A facet cyst is a very rare condition in the thoracolumbar spine and more so, hemorrhage into a cyst is extremely rare. We present a case of a facet cyst hematoma in the T12-L1 spine. A 69-year-old woman complained of chronic back pain with right lower extremity pain, and weakness for 3 years. MRI and MR myelography showed an extradural mass at the T12-L1 level with heterogeneous signal intensity on both T1-and T2-weighted images, which was continuous to the right T12-L1 facet joint. The neighboring facet joint showed severe degeneration on the CT scan. The mass a was simple hematoma covered with a thin fibrous membrane and connected with facet joint macroscopically and microscopically. The pathogenesis of the facet cyst hematoma is not clear but it can compress nerve roots or dura mater and cause radiculopathy or cauda equina syndrome. Surgical removal should be recommended for symptomatic relief.

Plantar impact causing midfoot fractures result in higher forces in Chopart's joint than in the ankle joint.

Science.gov (United States)

Richter, M; Wippermann, B; Thermann, H; Schroeder, G; Otte, D; Troeger, H D; Krettek, C

2002-03-01

Force effect (impact, extent of foot compartment deformation) and result (fracture pattern) for midfoot fractures in car occupants is known. An analysis of the processes in the foot was intended to improve car safety. Eleven fresh, unfrozen, unpreserved intact human cadavers (age: 36.8 (16-61) years, gender: male, race: Caucasian) were studied 24-72 h after death. In 3 cadavers (5 feet) the experimental design was established: entire cadaver fixed on a special tray in supine position, pendulum with bar impactor hitting the foot plantar to Lisfranc's joint. A custom-made pressure sensor was inserted in the ankle (A), talonavicular (TN) and calcaneocuboid (CC) joints (resolution: 1 cm2, sampling rate: 500/s). Sixteen feet were measured: midfoot fractures were induced in 11 feet. The maximum pressure amounted to 1.22-2.55 MPa (2.04+/-0.412) at 0.005 0.195 s (0.067+/-0.059) after impact. The maximum pressure occurred in 8 (50%) cases in the ankle, in 7 (44%) of the TN and 1 (6%) of the CC joints. A comparison of the first 200 pressure samples after impact of all sensor fields resulted in higher forces in Chopart's joint than in the ankle (t-test: p < 0.001). These force differences were higher in cases with midfoot fractures (mixed model analysis of variance: p = 0.003). Due to considerable forces in Chopart's joint we recommend a modification of the actual crash test dummy lower extremity model with an additional load cell that detects forces in the longitudinal direction of the foot axis.

Upper limb joint forces and moments during underwater cyclical movements.

Science.gov (United States)

Lauer, Jessy; Rouard, Annie Hélène; Vilas-Boas, João Paulo

2016-10-03

Sound inverse dynamics modeling is lacking in aquatic locomotion research because of the difficulty in measuring hydrodynamic forces in dynamic conditions. Here we report the successful implementation and validation of an innovative methodology crossing new computational fluid dynamics and inverse dynamics techniques to quantify upper limb joint forces and moments while moving in water. Upper limb kinematics of seven male swimmers sculling while ballasted with 4kg was recorded through underwater motion capture. Together with body scans, segment inertial properties, and hydrodynamic resistances computed from a unique dynamic mesh algorithm capable to handle large body deformations, these data were fed into an inverse dynamics model to solve for joint kinetics. Simulation validity was assessed by comparing the impulse produced by the arms, calculated by integrating vertical forces over a stroke period, to the net theoretical impulse of buoyancy and ballast forces. A resulting gap of 1.2±3.5% provided confidence in the results. Upper limb joint load was within 5% of swimmer׳s body weight, which tends to supports the use of low-load aquatic exercises to reduce joint stress. We expect this significant methodological improvement to pave the way towards deeper insights into the mechanics of aquatic movement and the establishment of practice guidelines in rehabilitation, fitness or swimming performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Effect of Foot Progression Angle on Knee Joint Compression Force during Walking

DEFF Research Database (Denmark)

Baldvinsson, Henrik Koblauch; Heilskov-Hansen, Thomas; Alkjær, Tine

2013-01-01

males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait-trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment......It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study...... was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy...

Estimation of the forces acting on the tibiofemoral joint during knee extension exercises

Directory of Open Access Journals (Sweden)

Rodrigo Rico Bini

2008-02-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n1p35 The objectives of this study were to: (1 evaluate the resistive torque of an open kinetic chain strength-training machine for performing knee extensions, and (2 perform an analysis estimating internal forces in the tibiofemoral joint. During a fi rst phase of the study, measurements were taken of the machine under analysis (external forces, and then calculations were performed to estimate forces on the lower limb (internal forces. Equations were defi ned to calculate human force (HF, and the moment of muscular force (MMF. Perpendicular muscular force (MFp and joint force (JFp, axial muscular force (MF” and joint force (JF”, and total muscular force (MF and joint force (JF were all calculated. Five knee angles were analyzed (zero, 30, 45, 60, and 90 degrees. A reduction was observed in HF at higher knee angles, while MF and JF also increased at the same time. HF was always lower than the load selected on the machine, which indicates a reduced overload imposed by the machine. The reduction observed in MFp and JFp at higher knee angles indicates a lower tendency to shear the tibia in relation to the femur. At the same time, there was an increase in JF” due to higher MF”. The biomechanical model proposed in this study has shown itself adequate for the day-to-day needs of professionals who supervise orient strength training.

Differences Regarding Branded HA in Italy, Part 2: Data from Clinical Studies on Knee, Hip, Shoulder, Ankle, Temporomandibular Joint, Vertebral Facets, and Carpometacarpal Joint

Science.gov (United States)

Migliore, A.; Bizzi, E.; De Lucia, O.; Delle Sedie, A.; Tropea, S.; Bentivegna, M.; Mahmoud, A.; Foti, C.

2016-01-01

OBJECTIVES The aim of the current study is to collect scientific data on all branded hyaluronic acid (HA) products in Italy that are in use for intra-articular (IA) injection in osteoarthritis (OA) compared with that reported in the leaflet. METHODS An extensive literature research was performed for all articles reporting data on the IA use of HA in OA. Selected studies were taken into consideration only if they are related to products based on HAs that are currently marketed in Italy with the specific joint indication for IA use in patients affected by OA. RESULTS Sixty-two HA products are marketed in Italy: 30 products are indicated for the knee but only 8 were proved with some efficacy; 9 products were effective for the hip but only 6 had hip indication; 7 products proved to be effective for the shoulder but only 3 had the indication; 5 products proved effective for the ankle but only one had the indication; 6 products were effective for the temporomandibular joint but only 2 had the indication; only 2 proved effective for vertebral facet joints but only 1 had the indication; and 5 products proved effective for the carpometacarpal joint but only 2 had the indication. CONCLUSIONS There are only a few products with some evidences, while the majority of products remain without proof. Clinicians and regulators should request postmarketing studies from pharmaceuticals to corroborate with that reported in the leaflet and to gather more data, allowing the clinicians to choose the adequate product for the patient. PMID:27279754

Facet orientation and tropism: Associations with asymmetric lumbar paraspinal and psoas muscle parameters in patients with chronic low back pain.

Science.gov (United States)

Xu, W B; Chen, S; Fan, S W; Zhao, F D; Yu, X J; Hu, Z J

2016-08-10

Many studies have explored the relationship between facet tropism and facet joint osteoarthritis, disc degeneration and degenerative spondylolisthesis. However, the associations between facet orientation and tropism, and paraspinal muscles have not been studied. To analyze the associations between facet orientation and tropism, and parameters of paraspinal muscles in patients with chronic low back pain. Ninety-five patients with chronic low back pain were consecutively enrolled. Their facet joint angles were measured on computed tomography (CT) while gross cross-sectional area (GCSA), functional cross-sectional area (FCSA) and T2 signal intensity of lumbar paraspinal and psoas muscle were evaluated on magnetic resonance imaging (MRI). The GCSA and FCSA were significantly smaller for multifidus muscle (Plow back pain. Longitudinal studies are needed to understand the causal relationship between facet orientation and tropism and muscular asymmetry in future.

Superior facet syndrome

International Nuclear Information System (INIS)

Kubo, Yoshichika; Igarashi, Seishi; Koyama, Tsunemaro

1985-01-01

Sciatica caused by root entrapment in the lateral recess was named superior facet syndrome by Epstein in 1972. Few reports on this subject based on large numbers of cases have been documented to date. Of the patients with sciatica, 32 patients were diagnosed to have root entrapment at the lateral recess L 5 or/and S 1 lumbar spine. Out of 32 patients, 20 patients were operated on and the lateral entrapment was recognized in all of surgical cases. Neuroradiological findings, especially of metrizamide CT (met. CT), were documented in detail. Thirty two patients were classified in three types according to radiological findings. They were congenital or developmental, degenerative, and combined type, respectively, Fourteen cases belonged to the congenital type, 13 to the degenerative and 5 to the combined type. Each group had the mean ages of 23.4, 53.8, and 36.8 years old, respectively. Of 32 cases the entrapment occured in 47 L 5 roots and 11 S 1 roots. There was no remarkable laterality. In operation the unroofing of the lateral recess were done and the sciatica subsided postoperatively in all of surgical cases. Met. CT revealed extreme medial protrusion of the superior articular joint in 18 of 24 cases(75%) and none filling of the root in the lateral recess in 21 of 24 cases (87.5%). In the degenerative type, met. CT showed some degenerative changes that were hypertrophy or deformity of the articular joints and spur formation of the vertebral body. In contrast to met. CT, metrizamide myelography revealed only slight changes, which were poor filling of the root before it turned out the pedicle of lateral compression of the root. In plain films or lumbar spine articular joints at Lsub(4/5) were formed in coronal plane in 69% of cases of the L 5 root entrapment. Met. CT using ReView technique was of great diagnostic value in superior facet syndrome. (author)

Distraction of facets with intraarticular spacers as treatment for lumbar canal stenosis: report on a preliminary experience with 21 cases.

Science.gov (United States)

Goel, Atul; Shah, Abhidha; Jadhav, Madan; Nama, Santhosh

2013-12-01

The authors report their experience in treating 21 patients by using a novel form of treatment of lumbar degenerative disease that leads to canal stenosis. The surgery involved distraction of the facets using specially designed Goel intraarticular spacers and was aimed at arthrodesis of the spinal segment in a distracted position. The operation is based on the premise that subtle and longstanding facet instability, joint space reduction, and subsequent facet override had a profound and primary influence in the pathogenesis of degenerative lumbar canal stenosis. The surgical technique and the rationale for treatment are discussed. Between April 2006 and January 2011, 21 cases of lumbar degenerative disease resulting in characteristic lumbar canal stenosis were treated in the authors' department with the proposed technique. The patients were prospectively analyzed. There were 15 men and 6 women who ranged in age from 48 to 71 years (mean 58 years). Nine patients underwent 1-level and 12 patients underwent 2-level treatment. Surgery involved wide opening of the articular joint, denuding of the articular capsule/endplate cartilage, distraction of the facets, and forced impaction of Goel intraarticular spacers. Bone graft pieces obtained by sectioning the spinous processes were placed within and over the joint and in the midline over the adequately prepared host area of laminae. The Oswestry Disability Index and visual analog scale were used to clinically assess the patients before and after surgery and at follow-up. The alterations in the physical architecture of spinal canal and intervertebral foramen dimensions were evaluated before and after placement of the intrafacet implant and after at least 6 months of follow-up. All patients had varying degrees of relief from symptoms of local back pain and radiculopathy. Impaction of spacers within the facet joints resulted in an increase in the spinal canal and intervertebral root canal dimensions (mean 2.33 mm), reduction

Can NATO's new Very High Readiness Joint Task Force deter?

DEFF Research Database (Denmark)

Rynning, Sten; Ringsmose, Jens

2017-01-01

” a distinct strategic rival – Russia. Chief among the Welsh summit initiatives was the decision to set up a new multinational spearhead force – the Very High Readiness Joint Task Force (VJTF) – as part of an enhanced NATO Response Force (NRF) and within the framework of a so-called Readiness Action Plan (RAP...

Facetal distraction as treatment for single- and multilevel cervical spondylotic radiculopathy and myelopathy: a preliminary report.

Science.gov (United States)

Goel, Atul; Shah, Abhidha

2011-06-01

The authors discuss their successful preliminary experience with 36 cases of cervical spondylotic disease by performing facetal distraction using specially designed Goel cervical facet spacers. The clinical and radiological results of treatment are analyzed. The mechanism of action of the proposed spacers and the rationale for their use are evaluated. Between 2006 and February 2010, 36 patients were treated using the proposed technique. Of these patients, 18 had multilevel and 18 had single-level cervical spondylotic radiculopathy and/or myelopathy. The average follow-up period was 17 months with a minimum of 6 months. The Japanese Orthopaedic Association classification system, visual analog scale (neck pain and radiculopathy), and Odom criteria were used to monitor the clinical status of the patient. The patients were prospectively analyzed. The technique of surgery involved wide opening of the facet joints, denuding of articular cartilage, distraction of facets, and forced impaction of Goel cervical facet spacers into the articular cavity. Additionally, the interspinous process ligaments were resected, and corticocancellous bone graft from the iliac crest was placed and was stabilized over the adjoining laminae and facets after adequately preparing the host bone. Eighteen patients underwent single-level, 6 patients underwent 2-level, and 12 patients underwent 3-level treatment. The alterations in the physical architecture of spine and canal dimensions were evaluated before and after the placement of intrafacet joint spacers and after at least 6 months of follow-up. All patients had varying degrees of relief from symptoms of pain, radiculopathy, and myelopathy. Analysis of radiological features suggested that the distraction of facets with the spacers resulted in an increase in the intervertebral foraminal dimension (mean 2.2 mm), an increase in the height of the intervertebral disc space (range 0.4-1.2 mm), and an increase in the interspinous distance (mean 2

Dual-joint modeling for estimation of total knee replacement contact forces during locomotion.

Science.gov (United States)

Hast, Michael W; Piazza, Stephen J

2013-02-01

Model-based estimation of in vivo contact forces arising between components of a total knee replacement is challenging because such forces depend upon accurate modeling of muscles, tendons, ligaments, contact, and multibody dynamics. Here we describe an approach to solving this problem with results that are tested by comparison to knee loads measured in vivo for a single subject and made available through the Grand Challenge Competition to Predict in vivo Tibiofemoral Loads. The approach makes use of a "dual-joint" paradigm in which the knee joint is alternately represented by (1) a ball-joint knee for inverse dynamic computation of required muscle controls and (2) a 12 degree-of-freedom (DOF) knee with elastic foundation contact at the tibiofemoral and patellofemoral articulations for forward dynamic integration. Measured external forces and kinematics were applied as a feedback controller and static optimization attempted to track measured knee flexion angles and electromyographic (EMG) activity. The resulting simulations showed excellent tracking of knee flexion (average RMS error of 2.53 deg) and EMG (muscle activations within ±10% envelopes of normalized measured EMG signals). Simulated tibiofemoral contact forces agreed qualitatively with measured contact forces, but their RMS errors were approximately 25% of the peak measured values. These results demonstrate the potential of a dual-joint modeling approach to predict joint contact forces from kinesiological data measured in the motion laboratory. It is anticipated that errors in the estimation of contact force will be reduced as more accurate subject-specific models of muscles and other soft tissues are developed.

Diagnostic value of lumbar facet joint injection: a prospective triple cross-over study.

Directory of Open Access Journals (Sweden)

Uwe Schütz

Full Text Available The diagnosis "lumbar facet syndrome" is common and often indicates severe lumbar spine surgery procedures. It is doubtful whether a painful facet joint (FJ can be identified by a single FJ block. The aim of this study was to clarify the validity of a single and placebo controlled bilateral FJ blocks using local anesthetics. A prospective single blinded triple cross-over study was performed. 60 patients (31 f, 29 m, mean age 53.2 yrs (22-73 with chronic low back pain (mean pain persistance 31 months, 6 months of conservative treatment without success admitted to a local orthopaedic department for surgical or conservative therapy of chronic LBP, were included in the study. Effect on pain reduction (10 point rating scale was measured. The 60 subjects were divided into six groups with three defined sequences of fluoroscopically guided bilateral monosegmental lumbar FJ test injections in "oblique needle" technique: verum-(local anaesthetic-, placebo-(sodium chloride- and sham-injection. Carry-over and periodic effects were evaluated and a descriptive and statistical analysis regarding the effectiveness, difference and equality of the FJ injections and the different responses was performed. The results show a high rate of non-response, which documents the lack of reliable and valid predictors for a positive response towards FJ blocks. There was a high rate of placebo reactions noted, including subjects who previously or later reacted positively to verum injections. Equivalence was shown among verum vs. placebo and partly vs. sham also. With regard to test validity criteria, a single intraarticular FJ block with local anesthetics is not useful to detect the pain-responsible FJ and therefore is no valid and reliable diagostic tool to specify indication of lumbar spine surgery. Comparative FJ blocks with local anesthetics and placebo-controls have to be interpretated carefully also, because they solely give no proper diagnosis on FJ being main pain

A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

International Nuclear Information System (INIS)

Tesfa, B; Horler, G; Thobiani, F Al; Gu, F; Ball, A D

2012-01-01

Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. 1. Sense changes in the clamping force of the joint and report this fact. 2. Provide compatibility with the large dynamic range of clamping force. 3. Satisfy the limitations in terms of physical size. 4. Provide the means to electronically interface with the washer. 5. Provide a means of powering the washer in situ. 6. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show

A feasibility study for experimentally determining dynamic force distribution in a lap joint

Energy Technology Data Exchange (ETDEWEB)

Mayes, Randall Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2013-11-01

Developing constitutive models of the physics in mechanical joints is currently stymied by inability to measure forces and displacements within the joint. The current state of the art estimates whole joint stiffness and energy loss per cycle from external measured force input and one or two acceleration responses. To validate constitutive models beyond this state requires a measurement of the distributed forces and displacements at the joint interface. Unfortunately, introducing measurement devices at the interface completely disrupts the desired physics. A feasibility study is presented for a non-intrusive method of solving for the interface dynamic forces from an inverse problem using full field measured responses. The responses come from the viewable surface of a beam. The noise levels associated with digital image correlation and continuous scanning laser Doppler velocimetry are evaluated from typical beam experiments. Two inverse problems are simulated. One utilizes the extended Sum of Weighted Accelerations Technique (SWAT). The second is a new approach dubbed the method of truncated orthogonal forces. These methods are much more robust if the contact patch geometry is well identified. Various approaches to identifying the contact patch are investigated, including ion marker tracking, Prussian blue and ultrasonic measurements. A typical experiment is conceived for a beam which has a lap joint at one end with a single bolt connecting it to another identical beam. In a virtual test using the beam finite element analysis, it appears that the SWAT inverse method requires evaluation of too many coefficients to adequately identify the force distribution to be viable. However, the method of truncated orthogonal forces appears viable with current digital image correlation (and probably other) imaging techniques.

A Common Force-Sharing Pattern in Joint Action That Consists of Four People.

Science.gov (United States)

Masumoto, Junya; Inui, Nobuyuki

2017-12-20

The authors examined the force-sharing patterns in a joint action performed by a group of two, three, or four people compared with a solo action. In the joint actions, 28 participants produced periodic isometric forces such that the sum of forces they produced cycled between 5% and 10% maximum voluntary contraction with the right hand at 1 Hz. In both the three- and four-person tasks, the correlation between forces produced by two of the three or four participants was negative, and the remaining one or two participants produced intermediate forces. The errors of force and interval and force variabilities were smaller in four- and three-people groups than individuals. Four- and three-people groups thus performed better than individuals.

Joint torques and joint reaction forces during squatting with a forward or backward inclined Smith machine.

Science.gov (United States)

Biscarini, Andrea; Botti, Fabio M; Pettorossi, Vito E

2013-02-01

We developed a biomechanical model to determine the joint torques and loadings during squatting with a backward/forward-inclined Smith machine. The Smith squat allows a large variety of body positioning (trunk tilt, foot placement, combinations of joint angles) and easy control of weight distribution between forefoot and heel. These distinctive aspects of the exercise can be managed concurrently with the equipment inclination selected to unload specific joint structures while activating specific muscle groups. A backward (forward) equipment inclination decreases (increases) knee torque, and compressive tibiofemoral and patellofemoral forces, while enhances (depresses) hip and lumbosacral torques. For small knee flexion angles, the strain-force on the posterior cruciate ligament increases (decreases) with a backward (forward) equipment inclination, whereas for large knee flexion angles, this behavior is reversed. In the 0 to 60 degree range of knee flexion angles, loads on both cruciate ligaments may be simultaneously suppressed by a 30 degree backward equipment inclination and selecting, for each value of the knee angle, specific pairs of ankle and hip angles. The anterior cruciate ligament is safely maintained unloaded by squatting with backward equipment inclination and uniform/forward foot weight distribution. The conditions for the development of anterior cruciate ligament strain forces are clearly explained.

An in-fiber Bragg grating sensor for contact force and stress measurements in articular joints

International Nuclear Information System (INIS)

Dennison, Christopher R; Wild, Peter M; Wilson, David R; Gilbart, Michael K

2010-01-01

We present an in-fiber Bragg grating-based sensor (240 µm diameter) for contact force/stress measurements in articular joints. The contact force sensor and another Bragg grating-based pressure sensor (400 µm diameter) are used to conduct the first simultaneous measurements of contact force/stress and fluid pressure in intact cadaveric human hips. The contact force/stress sensor addresses limitations associated with stress-sensitive films, the current standard tools for contact measurements in joints, including cartilage modulus-dependent sensitivity of films and the necessity to remove biomechanically relevant anatomy to implant the films. Because stress-sensitive films require removal of anatomy, it has been impossible to validate the mechanical rationale underlying preventive or corrective surgeries, which repair these anatomies, by conducting simultaneous stress and pressure measurements in intact hips. Methods are presented to insert the Bragg grating-based sensors into the joint, while relevant anatomy is left largely intact. Sensor performance is predicted using numerical models and the predicted sensitivity is verified through experimental calibrations. Contact force/stress and pressure measurements in cadaveric joints exhibited repeatability. With further validation, the Bragg grating-based sensors could be used to study the currently unknown relationships between contact forces and pressures in both healthy and degenerated joints

Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

Science.gov (United States)

Saito, Akira; Akima, Hiroshi

2013-12-01

It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

JOINT FORCE AND CONTEMPORARY MILITARY ACTIONS

Directory of Open Access Journals (Sweden)

Codrin HERTANU

2012-01-01

Full Text Available In the current changing international context, the worldwide power balance along with its inter-dependencies shows that mankind is facing problems and pressures posed by resources limitation (the oil ones being the most relevant dramatic climate evolution and a decisive impact of technologies. The approach of the armed forces to the national defense related interests, as well as to the asymmetrical and irregular threats underlines the joint force’s capacity to be the most powerful and adequate tool to address all of these.

Normalized patellofemoral joint reaction force is greater in individuals with patellofemoral pain.

Science.gov (United States)

Thomeer, Lucas T; Sheehan, Frances T; Jackson, Jennifer N

2017-07-26

Patellofemoral pain is a disabling, highly prevalent pathology. Altered patellofemoral contact forces are theorized to contribute to this pain. Musculoskeletal modeling has been employed to better understand the etiology of patellofemoral pain. Currently, there are no data on the effective quadriceps moment arm for individuals with patellofemoral pain, forcing researchers to apply normative values when modeling such individuals. In addition, the ratio of patellofemoral reaction force to quadriceps force is often used as a surrogate for patellofemoral joint contact force, ignoring the fact that the quadriceps efficiency can vary with pathology and intervention. Thus, the purposes of this study were to: (1) quantify the effective quadriceps moment arm in individuals with patellofemoral pain and compare this value to a control cohort and (2) develop a novel methodology for quantifying the normalized patellofemoral joint reaction force in vivo during dynamic activities. Dynamic MR data were captured as subjects with patellofemoral pain (30F/3M) cyclically flexed their knee from 10° to 40°. Data for control subjects (29F/9M) were taken from a previous study. The moment arm data acquired across a large cohort of individuals with patellofemoral pain should help advance musculoskeletal modeling. The primary finding of this study was an increased mean normalized patellofemoral reaction force of 14.9% (maximum values at a knee angle of 10°) in individuals with patellofemoral pain. Understanding changes in the normalized patellofemoral reaction force with pathology may lead to improvements in clinical decision making, and consequently treatments, by providing a more direct measure of altered patellofemoral joint forces. Copyright © 2017. Published by Elsevier Ltd.

GPS and the Joint Force Commander: Critical Asset, Critical Vulnerability

National Research Council Canada - National Science Library

McPherson, Michael

2001-01-01

Joint Force Commanders (JFCs) have become over reliant on military and commercial satellite systems for intelligence gathering and dissemination, weather, command, control, communications, and navigation/guidance functions, to name a few...

The International Criminal Court: Considerations for the Joint Force Commander

National Research Council Canada - National Science Library

Sutton, Michael

2003-01-01

An analysis of the issues and remedies a Joint Force Commander should be concerned about because of the relationship between the United States and the newly-created International Criminal Court (ICC...

Bilateral ground reaction forces and joint moments for lateral sidestepping and crossover stepping tasks

Science.gov (United States)

Kuntze, Gregor; Sellers, William I.; Mansfield, Neil

2009-01-01

Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS) and crossover stepping (XS) movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work. Key pointsGround reaction forces and joint moments during lateral stepping are smaller in magnitude than those experienced during moderate running.Force exposure in SS and XS gaits in normal play does not appear to contribute to the development of

Championing the Joint Force: A Job for the Public and our Political Leaders – Not Just Military Professionals Alone

Directory of Open Access Journals (Sweden)

Stuart Beare

2015-11-01

Full Text Available Canada’s security interests and the mission of our Armed Forces – that is to defend Canada, defend North America and to promote peace and security abroad – may largely remain unchanged and timeless. The nature of the security environment, however, has not – nor will it be in the years to come. An effective and relevant Canadian Armed Forces will continue to require capable, wellequipped and operationally-ready maritime, air and land forces who are largely raised and trained within our Army, Navy and Air Force. But in order for Defence to remain relevant and effective in an era of increased instability, volatility and unpredictability, our Armed Forces need the ability and capacity to match these with an increased understanding of what is going on, and preparedness for what is to come. This is the business of our military’s Joint Forces – those beyond the tactical units that the services provide. It is the joint organizations and networks within the institution that generate intelligence, provide understanding and lead the partnering, planning, force posturing and practicing so essential to the anticipation of, preparation for, and conduct of, operations – in particular in a world of unrelenting complexity. A decade after General Rick Hillier’s extraordinary initiatives to transform our Armed Forces from a service-centric machine-age force to one focused on the business of operations, one that thinks and acts Canadian Forces (joint first, we do see evidence of real progress in the approach to joint operations and improved appreciation of our military’s joint functions and capabilities. Unlike the political and public calls for strong services and the modernization of their major platforms, however, this progress has been realized largely through efforts internal to the Armed Forces themselves. The initiative has been without political leadership and external policy topcover, rendering this progress and its future vulnerable and

Joint Force Quarterly. Issue 57, 2nd Quarter 2010

Science.gov (United States)

2010-04-01

specialized equipment and chemicals.18 While this early work provides a proof of concept, genetic engineering and combinatorial chemistry in the future will...is, entails three steps. Using the reverse planning rubric , the first step is to determine the endstate or goal of joint force development, next

Estimation of ground reaction forces and joint moments on the basis on plantar pressure insoles and wearable sensors for joint angle measurement.

Science.gov (United States)

Ostaszewski, Michal; Pauk, Jolanta

2018-05-16

Gait analysis is a useful tool medical staff use to support clinical decision making. There is still an urgent need to develop low-cost and unobtrusive mobile health monitoring systems. The goal of this study was twofold. Firstly, a wearable sensor system composed of plantar pressure insoles and wearable sensors for joint angle measurement was developed. Secondly, the accuracy of the system in the measurement of ground reaction forces and joint moments was examined. The measurements included joint angles and plantar pressure distribution. To validate the wearable sensor system and examine the effectiveness of the proposed method for gait analysis, an experimental study on ten volunteer subjects was conducted. The accuracy of measurement of ground reaction forces and joint moments was validated against the results obtained from a reference motion capture system. Ground reaction forces and joint moments measured by the wearable sensor system showed a root mean square error of 1% for min. GRF and 27.3% for knee extension moment. The correlation coefficient was over 0.9, in comparison with the stationary motion capture system. The study suggests that the wearable sensor system could be recommended both for research and clinical applications outside a typical gait laboratory.

Anatomical kinematic constraints: consequences on muscular forces and joint reactions

OpenAIRE

MOISSENET, F; CHEZE, L; DUMAS, R

2011-01-01

This paper presents a method to determine musculo-tendon forces and joint reactions during gait, using a 3D right leg model with 5 DoFs: spherical joint at the hip and parallel mechanisms at both knee and ankle. A typical set of natural coordinates is used to obtain the dynamic equations. First, using a global optimization method, "anatomical" kinematic constraints (i.e., parallel mechanisms) are applied on the kinematics obtained from motion capture data. Consistent derivatives are computed ...

Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement.

Directory of Open Access Journals (Sweden)

Robert Rasnick

Full Text Available Total knee replacement (TKR is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05. No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups.

Development and Validation of the Faceted Inventory of the Five-Factor Model (FI-FFM).

Science.gov (United States)

Watson, David; Nus, Ericka; Wu, Kevin D

2017-06-01

The Faceted Inventory of the Five-Factor Model (FI-FFM) is a comprehensive hierarchical measure of personality. The FI-FFM was created across five phases of scale development. It includes five facets apiece for neuroticism, extraversion, and conscientiousness; four facets within agreeableness; and three facets for openness. We present reliability and validity data obtained from three samples. The FI-FFM scales are internally consistent and highly stable over 2 weeks (retest rs ranged from .64 to .82, median r = .77). They show strong convergent and discriminant validity vis-à-vis the NEO, the Big Five Inventory, and the Personality Inventory for DSM-5. Moreover, self-ratings on the scales show moderate to strong agreement with corresponding ratings made by informants ( rs ranged from .26 to .66, median r = .42). Finally, in joint analyses with the NEO Personality Inventory-3, the FI-FFM neuroticism facet scales display significant incremental validity in predicting indicators of internalizing psychopathology.

BILATERAL GROUND REACTION FORCES AND JOINT MOMENTS FOR LATERAL SIDESTEPPING AND CROSSOVER STEPPING TASKS

Directory of Open Access Journals (Sweden)

William I. Sellers

2009-03-01

Full Text Available Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS and crossover stepping (XS movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work

Ultrasound-guided facet block to low back pain: a case report

Directory of Open Access Journals (Sweden)

Ana Ellen Q. Santiago

2014-07-01

Full Text Available BACKGROUND: Osteoarthrosis is a common cause of low back pain. The diagnosis is clinical and can be confirmed by imaging studies. Pain treatment and confirmation of diagnosis are made by intra-articular injection of corticosteroid and by local anesthetic use, due to clinical improvement. A direct monitoring of the procedure can be done under fluoroscopy, a classic technique, or else by an ultrasound-guided procedure. CASE REPORT: Female patient, 88 years old, 1.68 m and 72 kg, with facet osteoarthrosis at L2-L3, L3-L4 and L4-L5 for two years. On physical examination, she exhibited pain on lateralization and spinal extension. We opted in favor of an ultrasound-guided facet joint block. A midline spinal longitudinal scan was obtained, with identification of the desired joint space at L3-L4. A 25 G needle was inserted into the skin by the echographic off-plane ultrasound technique. 1 mL of contrast was administered, with confirmation by fluoroscopy. After aspiration of the contrast, 1 mL of solution containing 0.25% bupivacaine hydrochloride and 10 mg of methylprednisolone acetate was injected. Injections into L3-L4, L2-L3 and L1-L2 to the right were applied. CONCLUSIONS: The visualization of the facet joint by ultrasound involves minimal risk, besides reduction of radiation. This option is suitable for a large part of the population. However, fluoroscopy and computed tomography remain as monitoring techniques indicated for patients with specific characteristics, such as obesity, severe degenerative diseases and anatomical malformations, in which the ultrasound technique is still in need of further study.

The cervical facet capsule and its role in whiplash injury: a biomechanical investigation.

Science.gov (United States)

Winkelstein, B A; Nightingale, R W; Richardson, W J; Myers, B S

2000-05-15

Cervical facet capsular strains were determined during bending and at failure in the human cadaver. To determine the effect of an axial pretorque on facet capsular strains and estimate the risk for subcatastrophic capsular injury during normal bending motions. Epidemiologic and clinical studies have identified the facet capsule as a potential site of injury and prerotation as a risk factor for whiplash injury. Unfortunately, biomechanical data on the cervical facet capsule and its role in whiplash injury are not available. Cervical spine motion segments were tested in a pure-moment test frame and the full-field strains determined throughout the facet capsule. Motion segments were tested with and without a pretorque in pure bending. The isolated facet was then elongated to failure. Maximum principal strains during bending were compared with failure strains, by paired t test. Statistically significant increases in principal capsular strains during flexion-extension loading were observed when a pretorque was applied. All measured strains during bending were significantly less than strains at catastrophic joint failure. The same was true for subcatastrophic ligament failure strains, except in the presence of a pretorque. Pretorque of the head and neck increases facet capsular strains, supporting its role in the whiplash mechanism. Although the facet capsule does not appear to be at risk for gross injury during normal bending motions, a small portion of the population may be at risk for subcatastrophic injury.

Photo-assisted Kelvin probe force microscopy investigation of three dimensional GaN structures with various crystal facets, doping types, and wavelengths of illumination

Science.gov (United States)

Ali Deeb, Manal; Ledig, Johannes; Wei, Jiandong; Wang, Xue; Wehmann, Hergo-Heinrich; Waag, Andreas

2017-08-01

Three dimensional GaN structures with different crystal facets and doping types have been investigated employing the surface photo-voltage (SPV) method to monitor illumination-induced surface charge behavior using Kelvin probe force microscopy. Various photon energies near and below the GaN bandgap were used to modify the generation of electron-hole pairs and their motion under the influence of the electric field near the GaN surface. Fast and slow processes for Ga-polar c-planes on both Si-doped n-type as well as Mg-doped p-type GaN truncated pyramid micro-structures were found and their origin is discussed. The immediate positive (for n-type) and negative (for p-type) SPV response dominates at band-to-band and near-bandgap excitation, while only the slow process is present at sub-bandgap excitation. The SPV behavior for the semi-polar facets of the p-type GaN truncated pyramids has a similar characteristic to that on its c-plane, which indicates that it has a comparable band bending and no strong influence of the polarity-induced charges is detectable. The SPV behavior of the non-polar m-facets of the Si-doped n-type part of a transferred GaN column is similar to that of a clean c-plane GaN surface during illumination. However, the SPV is smaller in magnitude, which is attributed to intrinsic surface states of m-plane surfaces and their influence on the band bending. The SPV behavior of the non-polar m-facet of the slightly Mg-doped part of this GaN column is found to behave differently. Compared to c- and r-facets of p-type surfaces of GaN-light-emitting diode micro-structures, the m-plane is more chemically stable.

Strategic Change and the Joint Terrorism Task Force: Ideas and Recommendations

National Research Council Canada - National Science Library

D'Angelo, Anthony P

2007-01-01

... and the multidisciplinary Joint Terrorism Task Forces. The terrorist attacks served as a catalyst for evaluating cultural, psychological and organizational processes, policies and procedures that influenced the FBI and impacted the JTTF program...

Surgical treatment of traumatic cervical facet dislocation: anterior, posterior or combined approaches?

Directory of Open Access Journals (Sweden)

Catarina C. Lins

Full Text Available ABSTRACT Surgical treatment is well accepted for patients with traumatic cervical facet joint dislocations (CFD, but there is uncertainty over which approach is better: anterior, posterior or combined. We performed a systematic literature review to evaluate the indications for anterior and posterior approaches in the management of CFD. Anterior approaches can restore cervical lordosis, and cause less postoperative pain and less wound problems. Posterior approaches are useful for direct reduction of locked facet joints and provide stronger fixation from a biomechanical point of view. Combined approaches can be used in more complex cases. Although both anterior and posterior approaches can be used interchangeably, there are some patients who may benefit from one of them over the other, as discussed in this review. Surgeons who treat cervical spine trauma should be able to perform both procedures as well as combined approaches to adequately manage CFD and improve patients’ final outcomes.

Can NATO's new very high readiness joint task force deter?

DEFF Research Database (Denmark)

Rynning, Sten; Ringsmose, Jens

2017-01-01

When NATO-allies met at their Wales summit in September 2014, the D-word was back in vogue. Not in a muttering, shy or implicit way, but unambiguously and straightforward. For the first time in more than two decades NATO’s heads of states and governments openly discussed how best to “deter......” a distinct strategic rival – Russia. Chief among the Welsh summit initiatives was the decision to set up a new multinational spearhead force – the Very High Readiness Joint Task Force (VJTF) – as part of an enhanced NATO Response Force (NRF) and within the framework of a so-called Readiness Action Plan (RAP...

Developing Doctrine for the Future Joint Force:. Creating Synergy and Minimizing Seams

National Research Council Canada - National Science Library

Brown Jr, Charles Q

2005-01-01

..., networked, decentralized, adaptable, decision superior, and lethal. Recent contingencies displayed rapidly executable, globally and operationally distributed, simultaneous, and sequential operations characteristic of the future joint force...

Faceted Search

CERN Document Server

Tunkelang, Daniel

2009-01-01

We live in an information age that requires us, more than ever, to represent, access, and use information. Over the last several decades, we have developed a modern science and technology for information retrieval, relentlessly pursuing the vision of a "memex" that Vannevar Bush proposed in his seminal article, "As We May Think." Faceted search plays a key role in this program. Faceted search addresses weaknesses of conventional search approaches and has emerged as a foundation for interactive information retrieval. User studies demonstrate that faceted search provides more

Significance of interfacet distance, facet joint orientation, and lumbar lordosis in spondylolysis.

Science.gov (United States)

Chung, Sang-Bong; Lee, Sungjoon; Kim, Hoon; Lee, Sun-Ho; Kim, Eun Sang; Eoh, Whan

2012-04-01

The aim of this study is to reveal the association between lumbar spondylolysis and several radiologic parameters, which had been suggested to be significant. The authors examine interfacet distance (IFD), facet joint orientation (FJO), and lumbar segmental lordosis (LSL) all together on the basis of lumbar computed tomography (CT) scan of 35 patients with L5 spondylolysis and 36 unaffected control groups. Thirty-five Korean military recruits, aged 19-23 (mean 20.9 years), were diagnosed as L5 spondylolysis by lumber CT scans. As a control group, 36 male Korean military recruits, aged 18-25 (mean 21.3 years), were reconfirmed as not affected by lumbar spondylolysis by CT scan when they visited our hospital complaining of back pain. This study compares IFD, FJO, and LSL for each lumbar segment between the spondylolytic and unaffected groups. We also propose the use of normal mean data of IFD, FJO, and LSL of lumbar vertebrae from 36 Korean young military recruits because each measurement has power as an absolute value, like data from an osteologic collection in other studies. Comparison of IFD between spondylolytic and unaffected individuals reveals significant differences at the L3, L4, and L5 level (P = 0.0384, P = 0.0219, and P spondylolysis, the increase of IFD from L4 to S1 was less pronounced (P spondylolysis and individuals without pars defect on L5. In the spondylolysis group, and the increase of IFD from L4 to S1 was less pronounced and the LSL at L5-S1 was more lordotic. Copyright © 2011 Wiley Periodicals, Inc.

Effect of the walking speed to the lower limb joint angular displacements, joint moments and ground reaction forces during walking in water.

Science.gov (United States)

Miyoshi, Tasuku; Shirota, Takashi; Yamamoto, Shin-ichiro; Nakazawa, Kimitaka; Akai, Masami

2004-06-17

The purpose of this study was to compare the changes in ground reaction forces (GRF), joint angular displacements (JAD), joint moments (JM) and electromyographic (EMG) activities that occur during walking at various speeds in water and on land. Fifteen healthy adults participated in this study. In the water experiments, the water depth was adjusted so that body weight was reduced by 80%. A video-motion analysis system and waterproof force platform was used to obtain kinematics and kinetics data and to calculate the JMs. Results revealed that (1) the anterior-posterior GRF patterns differed between walking in water and walking on land, whereas the medio-lateral GRF patterns were similar, (2) the JAD patterns of the hip and ankle were similar between water- and land-walking, whereas the range of motion at the knee joint was lower in water than on land, (3) the JMs in all three joints were lower in water than on land throughout the stance phase, and (4) the hip joint extension moment and hip extensor muscle EMG activity were increased as walking speed increase during walking in water. Rehabilitative water-walking exercise could be designed to incorporate large-muscle activities, especially of the lower-limb extensor muscles, through full joint range of motion and minimization of joint moments.

Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

Science.gov (United States)

Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

2016-01-01

Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (pknee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

Multiple joint muscle function with ageing: the force-velocity and power-velocity relationships in young and older men.

Science.gov (United States)

Allison, Sarah J; Brooke-Wavell, Katherine; Folland, Jonathan P

2013-05-01

Whilst extensive research has detailed the loss of muscle strength with ageing for isolated single joint actions, there has been little attention to power production during more functionally relevant multiple joint movements. The extent to which force or velocity are responsible for the loss in power with ageing is also equivocal. The aim of this study was to evaluate the contribution of force and velocity to the differences in power with age by comparing the force-velocity and power-velocity relationships in young and older men during a multiple joint leg press movement. Twenty-one older men (66 ± 3 years) and twenty-three young men (24 ± 2 years) completed a series of isometric (maximum and explosive) and dynamic contractions on a leg press dynamometer instrumented to record force and displacement. The force-velocity relationship was lower for the older men as reflected by their 19 % lower maximum isometric strength (p decrement in force was greater and therefore the major explanation for the attenuation of power during a functionally relevant multiple joint movement.

Forces on bends and T-joints due to multiphase flow

NARCIS (Netherlands)

Belfroid, S.P.C.; Cargnelutti, M.F.; Schiferli, W.; Osch, M.M.E. van

2010-01-01

To be able to assess the mechanical integrity of piping structures for loading to multiphase flow conditions, air-water experiments were carried out in a horizontal 1" pipe system. Forces and accelerations were measured on a number of bends and T-joint configurations for a wide range of operating

Forced-air warming discontinued: periprosthetic joint infection rates drop

Directory of Open Access Journals (Sweden)

Scott D. Augustine

2017-06-01

Full Text Available Several studies have shown that the waste heat from forced-air warming (FAW escapes near the floor and warms the contaminated air resident near the floor. The waste heat then forms into convection currents that rise up and contaminate the sterile field above the surgical table. It has been shown that a single airborne bacterium can cause a periprosthetic joint infection (PJI following joint replacement surgery. We retrospectively compared PJI rates during a period of FAW to a period of air-free conductive fabric electric warming (CFW at three hospitals. Surgical and antibiotic protocols were held constant. The pooled multicenter data showed a decreased PJI rate of 78% following the discontinuation of FAW and a switch to air-free CFW (n=2034; P=0.002. The 78% reduction in joint implant infections observed when FAW was discontinued suggests that there is a link between the waste FAW heat and PJIs.

Facet development for a faceted stretched-membrane dish by Solar Kinetics, Inc

Energy Technology Data Exchange (ETDEWEB)

Schertz, P.T.; Brown, D.C.; Konnerth, A. III (Solar Kinetics, Inc., Dallas, TX (United States))

1991-07-01

A 3.6-meter diameter stretched-membrane optical facet for a parabolic dish has been successfully designed and demonstrated under contract with Sandia National Laboratories. Twelve facets identical to them will be used to make the lightweight reflector of the dish. The project goal of 2.5-mrad surface accuracy was met with each of the two full-sized prototypes, and accuracies of as low as 1.1 mrad were achieved. The facet weight is 11.7 kg/m{sup 2} (2.4lbs/ft{sup 2}). The facet is similar in construction to the successful stretched-membrane heliostat; it has two thin metal membranes attached to a ring. However, the front membrane for this facet is plastically formed at the factor in order to achieve a shorter facet f/D (approximately 3.0). A passive tether restrains the from membrane when not in operation, that is, when the stabilizing vacuum is off. The optical surface is achieved with a silvered-acrylic film laminated to the metal membrane. The facet is expected to cost $55.40/m{sup 2} at a production rate of 10,000 facets per year and $115, 000/m{sup 2}-at a production rate of 500 facets a year. Several key issues have been resolved. Stress concentrations due to seams in the reflective laminate did not cause membrane rupture during forming as they have for dishes with lower focal length-to-diameter ratios. The laminate survived the forming process and simulated operation without deterioration. The optical effect of the tether on the membrane was tested and found to be very small. Most important, highly accurate shapes were obtained using a simple forming procedure. Additional tests are needed to demonstrate process repeatablility and facet performance in typical operating conditions. 18 refs., 36 figs., 11 tabs.

Joint Manipulation: Toward a General Theory of High-Velocity, Low-Amplitude Thrust Techniques.

Science.gov (United States)

Harwich, Andrew S

2017-12-01

The objective of this study was to describe the initial stage of a generalized theory of high-velocity, low-amplitude thrust (HVLAT) techniques for joint manipulation. This study examined the movements described by authors from the fields of osteopathy, chiropractic, and physical therapy to produce joint cavitation in both the metacarpophalangeal (MCP) joint and the cervical spine apophysial joint. This study qualitatively compared the kinetics, the similarities, and the differences between MCP cavitation and cervical facet joint cavitation. A qualitative vector analysis of forces and movements was undertaken by constructing computer-generated, simplified graphical models of the MCP joint and a typical cervical apophysial joint and imposing the motions dictated by the clinical technique. Comparing the path to cavitation of 2 modes of HVLAT for the MCP joint, namely, distraction and hyperflexion, it was found that the hyperflexion method requires an axis of rotation, the hinge axis, which is also required for cervical HVLAT. These results show that there is an analogue of cervical HVLAT in one of the MCP joint HVLATs. The study demonstrated that in a theoretical model, the path to joint cavitation is the same for asymmetric separation of the joint surfaces in the cervical spine and the MCP joints.

Flange joint system for SRF cavities utilizing high force spring clamps for low particle generation

Science.gov (United States)

None

2017-09-05

A flange joint system for SRF cavities. The flange joint system includes a set of high force spring clamps that produce high force on the simple flanges of Superconducting Radio Frequency (SRF) cavities to squeeze conventional metallic seals. The system establishes the required vacuum and RF-tight seal with minimum particle contamination to the inside of the cavity assembly. The spring clamps are designed to stay within their elastic range while being forced open enough to mount over the flange pair. Upon release, the clamps have enough force to plastically deform metallic seal surfaces and continue to a new equilibrium sprung dimension where the flanges remain held against one another with enough preload such that normal handling will not break the seal.

Can the Army Provide Bulk Petroleum Support to Joint Force 2020?

Science.gov (United States)

2013-03-01

Petroleum Officer (JPO) and one or more Sub Area Petroleum Officers ( SAPO ). The JPO coordinates petroleum support to all forces in a theater on behalf...position is the SAPO , established by the Combatant Commander or a Joint Force Commander (JFC) to fulfill bulk petroleum planning and execution in a...section of the theater for which the JPO is responsible.7 A key duty of the SAPO is to advise the JFC and his/her staff on petroleum logistics

sEMG-based joint force control for an upper-limb power-assist exoskeleton robot.

Science.gov (United States)

Li, Zhijun; Wang, Baocheng; Sun, Fuchun; Yang, Chenguang; Xie, Qing; Zhang, Weidong

2014-05-01

This paper investigates two surface electromyogram (sEMG)-based control strategies developed for a power-assist exoskeleton arm. Different from most of the existing position control approaches, this paper develops force control methods to make the exoskeleton robot behave like humans in order to provide better assistance. The exoskeleton robot is directly attached to a user's body and activated by the sEMG signals of the user's muscles, which reflect the user's motion intention. In the first proposed control method, the forces of agonist and antagonist muscles pair are estimated, and their difference is used to produce the torque of the corresponding joints. In the second method, linear discriminant analysis-based classifiers are introduced as the indicator of the motion type of the joints. Then, the classifier's outputs together with the estimated force of corresponding active muscle determine the torque control signals. Different from the conventional approaches, one classifier is assigned to each joint, which decreases the training time and largely simplifies the recognition process. Finally, the extensive experiments are conducted to illustrate the effectiveness of the proposed approaches.

Interspecific scaling patterns of talar articular surfaces within primates and their closest living relatives

Science.gov (United States)

Yapuncich, Gabriel S; Boyer, Doug M

2014-01-01

The articular facets of interosseous joints must transmit forces while maintaining relatively low stresses. To prevent overloading, joints that transmit higher forces should therefore have larger facet areas. The relative contributions of body mass and muscle-induced forces to joint stress are unclear, but generate opposing hypotheses. If mass-induced forces dominate, facet area should scale with positive allometry to body mass. Alternatively, muscle-induced forces should cause facets to scale isometrically with body mass. Within primates, both scaling patterns have been reported for articular surfaces of the femoral and humeral heads, but more distal elements are less well studied. Additionally, examination of complex articular surfaces has largely been limited to linear measurements, so that ‘true area' remains poorly assessed. To re-assess these scaling relationships, we examine the relationship between body size and articular surface areas of the talus. Area measurements were taken from microCT scan-generated surfaces of all talar facets from a comprehensive sample of extant euarchontan taxa (primates, treeshrews, and colugos). Log-transformed data were regressed on literature-derived log-body mass using reduced major axis and phylogenetic least squares regressions. We examine the scaling patterns of muscle mass and physiological cross-sectional area (PCSA) to body mass, as these relationships may complicate each model. Finally, we examine the scaling pattern of hindlimb muscle PCSA to talar articular surface area, a direct test of the effect of mass-induced forces on joint surfaces. Among most groups, there is an overall trend toward positive allometry for articular surfaces. The ectal (= posterior calcaneal) facet scales with positive allometry among all groups except ‘sundatherians', strepsirrhines, galagids, and lorisids. The medial tibial facet scales isometrically among all groups except lemuroids. Scaling coefficients are not correlated with sample

Reductions in knee joint forces with weight loss are attenuated by gait adaptations in class III obesity.

Science.gov (United States)

DeVita, Paul; Rider, Patrick; Hortobágyi, Tibor

2016-03-01

A consensus exists that high knee joint forces are a precursor to knee osteoarthritis and weight loss reduces these forces. Because large weight loss also leads to increased step length and walking velocity, knee contact forces may be reduced less than predicted by the magnitude of weight loss. The purpose was to determine the effects of weight loss on knee muscle and joint loads during walking in Class III obese adults. We determined through motion capture, force platform measures and biomechanical modeling the effects of weight loss produced by gastric bypass surgery over one year on knee muscle and joint loads during walking at a standard, controlled velocity and at self-selected walking velocities. Weight loss equaling 412 N or 34% of initial body weight reduced maximum knee compressive force by 824 N or 67% of initial body weight when walking at the controlled velocity. These changes represent a 2:1 reduction in knee force relative to weight loss when walking velocity is constrained to the baseline value. However, behavioral adaptations including increased stride length and walking velocity in the self-selected velocity condition attenuated this effect by ∼50% leading to a 392 N or 32% initial body weight reduction in compressive force in the knee joint. Thus, unconstrained walking elicited approximately 1:1 ratio of reduction in knee force relative to weight loss and is more indicative of walking behavior than the standard velocity condition. In conclusion, massive weight loss produces dramatic reductions in knee forces during walking but when patients stride out and walk faster, these favorable reductions become substantially attenuated. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of Spinal Manipulative Therapy Force Magnitude and Application Site on Spinal Tissue Loading: A Biomechanical Robotic Serial Dissection Study in Porcine Motion Segments.

Science.gov (United States)

Funabashi, Martha; Nougarou, François; Descarreaux, Martin; Prasad, Narasimha; Kawchuk, Greg

In order to define the relation between spinal manipulative therapy (SMT) input parameters and the distribution of load within spinal tissues, the aim of this study was to determine the influence of force magnitude and application site when SMT is applied to cadaveric spines. In 10 porcine cadavers, a servo-controlled linear actuator motor provided a standardized SMT simulation using 3 different force magnitudes (100N, 300N, and 500N) to 2 different cutaneous locations: L3/L4 facet joint (FJ), and L4 transverse processes (TVP). Vertebral kinematics were tracked optically using indwelling bone pins, the motion segment removed and mounted in a parallel robot equipped with a 6-axis load cell. The kinematics of each SMT application were replicated robotically. Serial dissection of spinal structures was conducted to quantify loading characteristics of discrete spinal tissues. Forces experienced by the L3/L4 segment and spinal structures during SMT replication were recorded and analyzed. Spinal manipulative therapy force magnitude and application site parameters influenced spinal tissues loading. A significant main effect (P < .05) of force magnitude was observed on the loads experienced by the intact specimen and supra- and interspinous ligaments. The main effect of application site was also significant (P < .05), influencing the loading of the intact specimen and facet joints, capsules, and ligamentum flavum (P < .05). Spinal manipulative therapy input parameters of force magnitude and application site significantly influence the distribution of forces within spinal tissues. By controlling these SMT parameters, clinical outcomes may potentially be manipulated. Copyright © 2017. Published by Elsevier Inc.

The Influence of Artificial Cervical Disc Prosthesis Height on the Cervical Biomechanics: A Finite Element Study.

Science.gov (United States)

Yuan, Wei; Zhang, Haiping; Zhou, Xiaoshu; Wu, Weidong; Zhu, Yue

2018-05-01

Artificial cervical disc replacement is expected to maintain normal cervical biomechanics. At present, the effect of the Prestige LP prosthesis height on cervical biomechanics has not been thoroughly studied. This finite element study of the cervical biomechanics aims to predict how the parameters, like range of motion (ROM), adjacent intradiscal pressure, facet joint force, and bone-implant interface stress, are affected by different heights of Prestige LP prostheses. The finite element model of intact cervical spine (C3-C7) was obtained from our previous study, and the model was altered to implant Prestige LP prostheses at the C5-C6 level. The effects of the height of 5, 6, and 7 mm prosthesis replacement on ROM, adjacent intradiscal pressure, facet joint force, as well as the distribution of bone-implant interface stress were examined. ROM, adjacent intradiscal pressure, and facet joint force increased with the prosthesis height, whereas ROM and facet joint force decreased at C5-C6. The maximal stress on the inferior surface of the prostheses was greater than that on the superior surface, and the stresses increased with the prosthesis height. The biomechanical changes were slightly affected by the height of 5 and 6 mm prostheses, but were strongly affected by the 7-mm prosthesis. An appropriate height of the Prestige LP prosthesis can preserve normal ROM, adjacent intradiscal pressure, and facet joint force. Prostheses with a height of ≥2 mm than normal can lead to marked changes in the cervical biomechanics and bone-implant interface stress. Copyright © 2018 Elsevier Inc. All rights reserved.

Adaptation of multi-joint balance coordination to whole body force fields

NARCIS (Netherlands)

Engelhart, Denise; Schouten, Alfred Christiaan; Pasma, Jantsje; Aarts, Ronald G.K.M.; Pasma, J.; Meskers, Carel; Maier, Andrea; van der Kooij, Herman

2014-01-01

Background and aim: The ankles and the hips play an important role in standing balance. Multi-joint coordination adapts with task, the magnitude and type of disturbance [1]. Arm studies show that postural responses are highly dependent on externally applied force fields [2]. Our aim is to study how

Facet-controlled synthesis and facet-dependent photocatalytic properties of SnO{sub 2} micropolyhedrons

Energy Technology Data Exchange (ETDEWEB)

Zhou, Gengxia [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Wu, Xinglong, E-mail: hkxlwu@nju.edu.cn [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Liu, Lizhe; Zhu, Xiaobin [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Zhu, Xiaoshu [Center for Analysis and Testing, Nanjing Normal University, Nanjing 210093 (China); Hao, Yanling [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-09-15

Graphical abstract: - Highlights: • SnO{sub 2} micropolyhedrons with (1 0 1) and (1 0 0) facets at different ratios are fabricated. • The vapor–solid growth mechanism of micropolyhedrons is discussed. • SnO{sub 2} octahedrons with complete (1 0 1) facets show strong photocatalytic activity. • Enhanced photocatalytic activity stems from the facet-dependent surface states. - Abstract: The facet-dependent properties of SnO{sub 2} are of fundamental and practical importance. In this study, by adjusting the deposition temperature during chemical vapor deposition, octahedral SnO{sub 2} with the exposed (1 0 1) facet and two other kinds of SnO{sub 2} polyhedrons with (1 0 1) and (1 0 0) facets with different ratios are fabricated controllably based on the vapor–solid growth mechanism. A slight increase in the deposition temperature from 1030 to 1070 °C decreases the surface energy of the reduced (1 0 1) facet with Sn termination, leading to the formation of polyhedrons with different area ratios of (1 0 1) to (1 0 0) facets. By adopting the terephthalic acid fluorescent method, the SnO{sub 2} octahedrons are demonstrated to have the strongest photocatalytic activity due to the formation of surface states induced by 5s electrons of bivalent Sn on the (1 0 1) surface. The results reveal that the photocatalytic properties of SnO{sub 2} microcrystals can be enhanced by facet-controlled synthesis.

Force-Sensing Actuator with a Compliant Flexure-Type Joint for a Robotic Manipulator

Directory of Open Access Journals (Sweden)

Mathieu Grossard

2015-12-01

Full Text Available This paper deals with the mechatronic design of a novel self-sensing motor-to-joint transmission to be used for the actuation of robotic dexterous manipulators. Backdrivability, mechanical simplicity and efficient flexure joint structures are key concepts that have guided the mechanical design rationale to provide the actuator with force sensing capabilities. Indeed, a self-sensing characteristic is achieved by the specific design of high-resolution cable-driven actuators based on a DC motor, a ball-screw and a monolithic compliant anti-rotation system together with a novel flexure pivot providing a frictionless mechanical structure. That novel compliant pivot with a large angular range and a small center shift has been conceived of to provide the inter-phalangeal rotational degree of freedom of the fingers’ joints to be used for integration in a multi-fingered robotic gripper. Simultaneously, it helps to remove friction at the joint level of the mechanism. Experimental tests carried out on a prototype show an accurate matching between the model and the real behavior. Overall, this mechatronic design contributes to the improvement of the manipulation skills of robotic grippers, thanks to the combination of high performance mechanics, high sensitivity to external forces and compliance control capability.

Chronic whiplash-associated disorder and traumatic cerebrospinal fluid leak. Analysis of cases with radioisotope cisternography, epidural blood patch, and cervical facet joint blocks

International Nuclear Information System (INIS)

Ishikawa, Shinichi; Kobayashi, Hiroyuki; Takahara, Hiroshi; Kojo, Shigeru; Hashimoto, Hidenori; Moriyama, Eiji; Nishida, Ayumi

2008-01-01

This paper describes RI cisternographic (RIC) examinations of whiplash-associated disorder (WAD) and results of their treatment with nerve block and epidural blood patch (EBP) conducted in authors' facilities. Subjects were 40 chronic (av. symptomatic period of 3.1 y) WAD patients (av. age 34 y) with traffic (28 cases), sports (7) and falling (5) causes with complication of suspicious cerebrospinal fluid (CSF) leak. RIC was done 2.5-24 hr after injection of 37 MBq of 111 In-diethylenetriamine pentaacetic acid (DTPA) in the medullary space through epidural puncturing needle. Positive finding of clear leak or early accumulation of RI in the bladder was seen in 21 cases and negative, in 19. Positive patients had significantly higher rates of headache, abnormal vision and fatigue than negative ones. EBP was conducted through X-ray to all positive patients and to negative ones with strongly suspicious leak complication (7 cases), which resulted in improvement of symptoms like headache and vision in the former, but no improvement in the latter cases. Repeated RIC of the patients with poor improvement in the former was suggested effective for judgment of repetition of EBP treatment. Cervical facet joint blocks were found effective in cases with posterior cervical pain. Symptoms in WAD accompanying headache should be differentially diagnosed whether it is derived from posttraumatic CSF leak or from pain due to cervical facet arthritis. (R.T.)

Summary of the 19th Joint EU-US Transport Task Force Workshop

DEFF Research Database (Denmark)

Angioni, C.; Mantica, P.; Naulin, Volker

2015-01-01

This conference report summarizes the contributions to, and discussions at, the 19th Joint EU-US Transport Task Force workshop, held in Culham, UK, during 8-11 September 2014. The workshop was organized under six topics: momentum transport, energetic particles, challenges in modelling transport i...

Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor.

Science.gov (United States)

Zhao, Yanzhi; Cao, Yachao; Zhang, Caifeng; Zhang, Dan; Zhang, Jie

2017-09-29

By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint) parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H) method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments.

Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor

Directory of Open Access Journals (Sweden)

Yanzhi Zhao

2017-09-01

Full Text Available By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments.

Effects of Facet Joint Injection Reducing the Need for Percutaneous Vertebroplasty in Vertebral Compression Fractures

Energy Technology Data Exchange (ETDEWEB)

Im, Tae Seong; Lee, Joon Woo; Lee, Eugene; Kang, Yusuhn; Ahn, Joong Mo, E-mail: joongmoahn@gmail.com; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology (Korea, Republic of)

2016-05-15

ObjectiveTo evaluate the effects of facet joint injection (FJI) reducing the need for percutaneous vertebroplasty (PVP) in cases of vertebral compression fracture (VCF).Materials and MethodsA total of 169 patients who were referred to the radiology department of our institution for PVP between January 2011 and December 2014 were retrospectively evaluated. The effectiveness of FJI was evaluated by the proportion of patients who cancelled PVP and who experienced reduced pain. In addition, by means of medical chart and MRI review, those clinical factors (age, sex, history of trauma, amount of injected steroids and interval days elapsed between VCF and FJI) and MR image factors (kyphosis angle, height loss, single or multiple level of VCF, burst fracture, central canal compromise, posterior element injury) that were believed to be significant for the effectiveness of FJI were statistically analysed.ResultsIn the 26 patients with FJI prior to PVP, six (23 %) patients cancelled PVP with considerable improvement in reported pain. In the 20 patients with PVP after FJI, improvement in pain after FJI was reported by six patients, resulting in a total of 12 patients (46 %) who experienced reduced pain after FJI. Clinical factors and MR image factors did not show any statistically significant difference between those groups, divided by PVP cancellation and by improvement of pain.ConclusionAfter FJI prior to PVP, about one quarter of patients cancelled PVP due to reduced pain and overall about half of the patients experienced reduced pain.

Sacroiliac joint dysfunction.

Science.gov (United States)

Ilaslan, Hakan; Arslan, Ahmet; Koç, Omer Nadir; Dalkiliç, Turker; Naderi, Sait

2010-07-01

Sacroiliac joint dysfunction is a disorder presenting with low back and groin pain. It should be taken into consideration during the preoperative differential diagnosis of lumbar disc herniation, lumbar spinal stenosis and facet syndrome. Four cases with sacroiliac dysfunction are presented. The clinical and radiological signs supported the evidence of sacroiliac dysfunction, and exact diagnosis was made after positive response to sacroiliac joint block. A percutaneous sacroiliac fixation provided pain relief in all cases. The mean VAS scores reduced from 8.2 to 2.2. It is concluded that sacroiliac joint dysfunction diagnosis requires a careful physical examination of the sacroiliac joints in all cases with low back and groin pain. The diagnosis is made based on positive response to the sacroiliac block. Sacroiliac fixation was found to be effective in carefully selected cases.

Dynamic simulation of knee-joint loading during gait using force-feedback control and surrogate contact modelling.

Science.gov (United States)

Walter, Jonathan P; Pandy, Marcus G

2017-10-01

The aim of this study was to perform multi-body, muscle-driven, forward-dynamics simulations of human gait using a 6-degree-of-freedom (6-DOF) model of the knee in tandem with a surrogate model of articular contact and force control. A forward-dynamics simulation incorporating position, velocity and contact force-feedback control (FFC) was used to track full-body motion capture data recorded for multiple trials of level walking and stair descent performed by two individuals with instrumented knee implants. Tibiofemoral contact force errors for FFC were compared against those obtained from a standard computed muscle control algorithm (CMC) with a 6-DOF knee contact model (CMC6); CMC with a 1-DOF translating hinge-knee model (CMC1); and static optimization with a 1-DOF translating hinge-knee model (SO). Tibiofemoral joint loads predicted by FFC and CMC6 were comparable for level walking, however FFC produced more accurate results for stair descent. SO yielded reasonable predictions of joint contact loading for level walking but significant differences between model and experiment were observed for stair descent. CMC1 produced the least accurate predictions of tibiofemoral contact loads for both tasks. Our findings suggest that reliable estimates of knee-joint loading may be obtained by incorporating position, velocity and force-feedback control with a multi-DOF model of joint contact in a forward-dynamics simulation of gait. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Indian Hedgehog signaling pathway members are associated with magnetic resonance imaging manifestations and pathological scores in lumbar facet joint osteoarthritis

Science.gov (United States)

Shuang, Feng; Zhou, Ying; Hou, Shu-Xun; Zhu, Jia-Liang; Liu, Yan; Zhang, Chun-Li; Tang, Jia-Guang

2015-05-01

Indian Hedgehog (HH) has been shown to be involved in osteoarthritis (OA) in articular joints, where there is evidence that Indian HH blockade could ameliorate OA. It seems to play a prominent role in development of the intervertebral disc (IVD) and in postnatal maintenance. There is little work on IHH in the IVD. Hence the aim of the current study was to investigate the role of Indian Hedgehog in the pathology of facet joint (FJ) OA. 24 patients diagnosed with lumbar intervertebral disk herniation or degenerative spinal stenosis were included. Preoperative magnetic resonance imaging (MRI) and Osteoarthritis Research Society International (OARSI) histopathology grading system was correlated to the mRNA levels of GLI1, PTCH1, and HHIP in the FJs. The Weishaupt grading and OARSI scores showed high positive correlation (r = 0.894) (P < 0.01). MRI Weishaupt grades showed positive correlation with GLI1 (r = 0.491), PTCH1 (r = 0.444), and HHIP (r = 0.654) mRNA levels (P < 0.05 in each case). OARSI scores were also positively correlated with GLI1 (r = 0. 646), PTCH1 (r = 0. 518), and HHIP (r = 0.762) mRNA levels (P < 0.01 in each case). Cumulatively our findings indicate that Indian HH signaling is increased in OA and is perhaps a key component in OA pathogenesis and progression.

FACET

International Nuclear Information System (INIS)

Cole, C.W.; Banszky, I.J.

1989-01-01

The merits of using commercially available software packages versus in-house software and databases are frequently assessed by cost engineers in consulting, contracting and operating companies alike. There is no consensus on which approach is better as each company has individual requirements that are better provided for by one or the other alternative. This paper describes Mobil Oil Canada's FACET (Facilities Cost Estimating Techniques) programs and provides a framework for building any successful in-house PC-based cost estimating and control system. The FACET series of programs enables detailed cost estimates to be quickly developed from relatively conceptual cost data and allows project cost estimates to be compared with actual costs as the project proceeds

PRELIMINARY STUDIES OF RIVETED JOINTS AT FEED FORCE

Directory of Open Access Journals (Sweden)

Radosław Bielawski

2015-08-01

Full Text Available The aim of the study was to determine the feasibility of riveted joints in composites materials. Static tensile test method was used. In the test one type of glass fabric was used (Interglas 92140 from which two types of composite samples were prepared. In each sample the same type of fiber with the same fiber orientation – 3 layers - was used. The samples had dimensions of 100×100 mm and thickness of approximately 1 mm. The composite probes were located in a metal frame with a screw connection which was made of screws with nominal thread pitch M5. Screws were tightened with constant torque. It was to provide an axial force to the sample during the tensile test. The frame was placed between cross-bars of tensile machine INSTRON 8516. The samples were stretched at a speed of 0.05 mm/s at a distance up to 16 mm. During the tensile test displacement of the samples and pull force were registered. Depending on the fibre orientations and the value of feed force, damage models were described. On the basis of the results the possibility of usage of aluminium rivet nuts connections in composite materials was determined.

Superior facet syndrome. Findings on metrizamide CT myelography

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Kubo, Yoshichika; Igarashi, Seishi; Koyama, Tsunemaro

1985-02-01

Sciatica caused by root entrapment in the lateral recess was named superior facet syndrome by Epstein in 1972. Few reports on this subject based on large numbers of cases have been documented to date. Of the patients with sciatica, 32 patients were diagnosed to have root entrapment at the lateral recess L5 or/and S1 lumbar spine. Out of 32 patients, 20 patients were operated on and the lateral entrapment was recognized in all of surgical cases. Neuroradiological findings, especially of metrizamide CT (met. CT), were documented in detail. Thirty two patients were classified in three types according to radiological findings. They were congenital or developmental, degenerative, and combined type, respectively. Fourteen cases belonged to the congenital type, 13 to the degenerative and 5 to the combined type. Each group had the mean ages of 23.4, 53.8, and 36.8 years old, respectively. Of 32 cases the entrapment occured in 47 L5 roots and 11 S1 roots. There was no remarkable laterality. In operation the unroofing of the lateral recess were done and the sciatica subsided postoperatively in all of surgical cases. Met. CT revealed extreme medial protrusion of the superior articular joint in 18 of 24 cases(75%) and none filling of the root in the lateral recess in 21 of 24 cases (87.5%). In the degenerative type, met. CT showed some degenerative changes that were hypertrophy or deformity of the articular joints and spur formation of the vertebral body. In contrast to met. CT, metrizamide myelography revealed only slight changes, which were poor filling of the root before it turned out the pedicle of lateral compression of the root. In plain films or lumbar spine articular joints at Lsub(4/5) were formed in coronal plane in 69% of cases of the L5 root entrapment. Met. CT using ReView technique was of great diagnostic value in superior facet syndrome.

Reductions in knee joint forces with weight loss are attenuated by gait adaptations in class III obesity

NARCIS (Netherlands)

DeVita, Paul; Rider, Patrick; Hortobagyi, Tibor

A consensus exists that high knee joint forces are a precursor to knee osteoarthritis and weight loss reduces these forces. Because large weight loss also leads to increased step length and walking velocity, knee contact forces may be reduced less than predicted by the magnitude of weight loss. The

A numerical study on stress distribution across the ankle joint: Effects of material distribution of bone, muscle force and ligaments.

Science.gov (United States)

Mondal, Subrata; Ghosh, Rajesh

2017-09-01

The goal of this study is to develop a realistic three dimensional FE model of intact ankle joint. Three dimensional FE model of the intact ankle joint was developed using computed tomography data sets. The effect of muscle force, ligaments and proper material property distribution of bone on stress distribution across the intact ankle joint was studied separately. Present study indicates bone material property, ligaments and muscle force have influence on stress distribution across the ankle joint. Proper bone material, ligaments and muscle must be considered in the computational model for pre-clinical analysis of ankle prosthesis.

Facets of Facebook: Use and Users

OpenAIRE

2016-01-01

The debate on Facebook raises questions about the use and users of this information service. This collected volume gathers a broad spectrum of social science and information science articles about Facebook.Facebook has many facets, and we just look forward above all to the use and users. The facet of users has sub-facets, such as different age, sex, and culture. The facet of use consists of sub-facets of privacy behavior after the Snowden affair, dealing with friends, unfriending and becoming...

Mathematical Model and Calibration Experiment of a Large Measurement Range Flexible Joints 6-UPUR Six-Axis Force Sensor

Directory of Open Access Journals (Sweden)

Yanzhi Zhao

2016-08-01

Full Text Available Nowadays improving the accuracy and enlarging the measuring range of six-axis force sensors for wider applications in aircraft landing, rocket thrust, and spacecraft docking testing experiments has become an urgent objective. However, it is still difficult to achieve high accuracy and large measuring range with traditional parallel six-axis force sensors due to the influence of the gap and friction of the joints. Therefore, to overcome the mentioned limitations, this paper proposed a 6-Universal-Prismatic-Universal-Revolute (UPUR joints parallel mechanism with flexible joints to develop a large measurement range six-axis force sensor. The structural characteristics of the sensor are analyzed in comparison with traditional parallel sensor based on the Stewart platform. The force transfer relation of the sensor is deduced, and the force Jacobian matrix is obtained using screw theory in two cases of the ideal state and the state of flexibility of each flexible joint is considered. The prototype and loading calibration system are designed and developed. The K value method and least squares method are used to process experimental data, and in errors of kind Ι and kind II linearity are obtained. The experimental results show that the calibration error of the K value method is more than 13.4%, and the calibration error of the least squares method is 2.67%. The experimental results prove the feasibility of the sensor and the correctness of the theoretical analysis which are expected to be adopted in practical applications.

Mathematical Model and Calibration Experiment of a Large Measurement Range Flexible Joints 6-UPUR Six-Axis Force Sensor.

Science.gov (United States)

Zhao, Yanzhi; Zhang, Caifeng; Zhang, Dan; Shi, Zhongpan; Zhao, Tieshi

2016-08-11

Nowadays improving the accuracy and enlarging the measuring range of six-axis force sensors for wider applications in aircraft landing, rocket thrust, and spacecraft docking testing experiments has become an urgent objective. However, it is still difficult to achieve high accuracy and large measuring range with traditional parallel six-axis force sensors due to the influence of the gap and friction of the joints. Therefore, to overcome the mentioned limitations, this paper proposed a 6-Universal-Prismatic-Universal-Revolute (UPUR) joints parallel mechanism with flexible joints to develop a large measurement range six-axis force sensor. The structural characteristics of the sensor are analyzed in comparison with traditional parallel sensor based on the Stewart platform. The force transfer relation of the sensor is deduced, and the force Jacobian matrix is obtained using screw theory in two cases of the ideal state and the state of flexibility of each flexible joint is considered. The prototype and loading calibration system are designed and developed. The K value method and least squares method are used to process experimental data, and in errors of kind Ι and kind II linearity are obtained. The experimental results show that the calibration error of the K value method is more than 13.4%, and the calibration error of the least squares method is 2.67%. The experimental results prove the feasibility of the sensor and the correctness of the theoretical analysis which are expected to be adopted in practical applications.

Correlation between facet tropism and lumbar degenerative disease: a retrospective analysis.

Science.gov (United States)

Gao, Tian; Lai, Qi; Zhou, Song; Liu, Xuqiang; Liu, Yuan; Zhan, Ping; Yu, Xiaolong; Xiao, Jun; Dai, Min; Zhang, Bin

2017-11-22

The aim of this study was to investigate the correlation between facet tropism and spinal degenerative diseases, such as degenerative lumbar spondylolisthesis, degenerative lumbar scoliosis, and lumbar disc herniation. This study retrospectively analysed clinical data from the Department of Orthopaedics at The First Affiliated Hospital of Nanchang University. Ninety-two patients were diagnosed with lumbar spondylolisthesis, 64 patients with degenerative scoliosis, and 86 patients with lumbar disc herniation between 1 October 2014 and 1 October 2016. All patients were diagnosed using 3.0 T magnetic resonance imaging and underwent conservative or operative treatment. Facet tropism was defined as greater than a ten degree between the facet joint angles on both sides. For L3-L4 degenerative lumbar spondylolisthesis, one out of six cases had tropism compared to seven out of the 86 controls (p = 0.474). At the L4-L5 level, 17/50 cases had tropism compared to 4/42 cases in the control group (p = 0.013). At the L5-S1 level, 18/36 cases had tropism compared to 7/56 controls (p = 0.000). For degenerative lumbar scoliosis at the L1-L5 level, 83/256 cases had tropism as compared to 36/256 controls (p = 0.000). For L3-L4 lumbar disc herniation two out of eight cases had tropism compared to 14/78 controls (p = 0.625). At the L4-L5 level, 19/44 cases had tropism compared to four out of 42 controls (p = 0.001). At the L5-S1 level, 24/34 cases had tropism compared to 10/52 controls (p = 0.000). At the L4-5 and L5-S1 levels, facet tropism is associated with degenerative spondylolisthesis. In the degenerative lumbar scoliosis group, the number of case with facet tropism was significantly higher than that of the control group. Facet tropism was associated with lumbar disc herniation at the L4-5 and L5-S1 levels. Overall, in these three lumbar degenerative diseases, facet tropism is a common phenomenon.

Trust: The Key to the Success of Mission Command in the Joint Force

Science.gov (United States)

2015-05-18

Malaysia , Kuala Lumpur: International Conference on ISO9000. Schmidt, Todd A. “Design, Mission Command and the Network: Enabling Organization...trust.pdf. Steele , Dennis. “Setting the Azimuth for Joint Force 2020: Globally Integrated Operations and Mission Command.” Army Magazine, November

An instrumented implant for in vivo measurement of contact forces and contact moments in the shoulder joint.

Science.gov (United States)

Westerhoff, P; Graichen, F; Bender, A; Rohlmann, A; Bergmann, G

2009-03-01

To improve implant design, fixation and preclinical testing, implant manufacturers depend on realistic data of loads acting on the shoulder joint. Furthermore, these data can help to optimize physiotherapeutic treatment and to advise patients in their everyday living conditions. Calculated shoulder joint loads vary extremely among different authors [Anglin C, Wyss UP, Pichora DR. Glenohumeral contact forces. Proc Inst Mech Eng [H] 2000;214:637-44]. Additionally the moments acting in the joint caused by friction or incongruent articular surfaces, for example, are not implemented in most models. An instrumented shoulder joint implant was developed to measure the contact forces and the contact moments acting in the glenohumeral joint. This article provides a detailed description of the implant, containing a nine-channel telemetry unit, six load sensors and an inductive power supply, all hermetically sealed inside the implant. The instrumented implant is based on a clinically proven BIOMET Biomodular shoulder replacement and was calibrated before implantation by using complex mathematical calculation routines in order to achieve an average measuring precision of approximately 2%.

Joint Force Quarterly. Issue 41, 2nd Quarter, April 2006

Science.gov (United States)

2006-04-01

companies participated, a million more people would be actively looking for threats. Aguas de Amazonas, a subsidiary of Suez Environnement, a...9 Richard B. Myers, “A Word from the Chair- man,” Joint Force Quarterly 37 (2d Quarter 2005), 5. 10 Wald, 26. 11 “Suez— Aguas de Amazonas Water for...humanitarian duties. They have overseen over 130 humani- tarian projects worth in excess of $7.6 million and ranging from a medical center, to potable

Facet Effusion without Radiographic Instability Has No Effect on the Outcome of Minimally Invasive Decompression Surgery.

Science.gov (United States)

Tamai, Koji; Kato, Minori; Konishi, Sadahiko; Matsumura, Akira; Hayashi, Kazunori; Nakamura, Hiroaki

2017-02-01

Retrospective cohort study. Lumbar segmental instability is a key factor determining whether decompression alone or decompression and fusion surgery is required to treat lumbar spinal stenosis (LSS). Some recent reports have suggested that facet joint effusion is correlated with spinal segmental instability. The aim of this study is to report the effect of facet effusion without radiographic segmental instability on the outcome of less-invasive decompression surgery for LSS. Seventy-nine patients with LSS (32 women, mean age: 69.1 ± 9.1 years) who had no segmental instability on dynamic radiographs before undergoing L4-L5 microsurgical decompression and who were followed for at least 2 years postoperatively were analyzed. They were divided into three groups on the basis of the existence and size of L4-L5 facet effusion using preoperative magnetic resonance imaging: grade 0 had no effusion ( n  = 31), grade 1 had measurable effusion ( n  = 35), and grade 2 had large effusion ( n  = 13). Japanese Orthopedics Association (JOA) score, visual analog scale (VAS), and the Short-Form (SF)-36 scores were recorded preoperatively and 12 and 24 months postoperatively. JOA score; VAS of low back pain, leg pain, and numbness; and SF-36 (physical component summary and mental component summary) scores did not differ significantly between the three groups in every terms ( p  = 0.921, 0.996, 0.950, 0.693, 0.374, 0.304, and 0.624, respectively, at final follow-up). In the absence of radiographic instability, facet joint effusion has no effect on the outcome of less-invasive decompression surgery.

Effect of lateralized design on muscle and joint reaction forces for reverse shoulder arthroplasty.

Science.gov (United States)

Liou, William; Yang, Yang; Petersen-Fitts, Graysen R; Lombardo, Daniel J; Stine, Sasha; Sabesan, Vani J

2017-04-01

Manufacturers of reverse shoulder arthroplasty (RSA) implants have recently designed innovative implants to optimize performance in rotator cuff-deficient shoulders. These advancements are not without tradeoffs and can have negative biomechanical effects. The objective of this study was to develop an integrated finite element analysis-kinematic model to compare the muscle forces and joint reaction forces (JRFs) of 3 different RSA designs. A kinematic model of a normal shoulder joint was adapted from the Delft model and integrated with the well-validated OpenSim shoulder model. Static optimizations then allowed for calculation of the individual muscle forces, moment arms, and JRFs relative to net joint moments. Three-dimensional computer models of 3 RSA designs-humeral lateralized design (HLD), glenoid lateralized design, and Grammont design-were integrated, and parametric studies were performed. Overall, there were decreases in deltoid and rotator cuff muscle forces for all 3 RSA designs. These decreases were greatest in the middle deltoid of the HLD model for abduction and flexion and in the rotator cuff muscles under both internal rotation and external rotation. The JRFs in abduction and flexion decreased similarly for all RSA designs compared with the normal shoulder model, with the greatest decrease seen in the HLD model. These findings demonstrate that the design characteristics implicit in these modified RSA prostheses result in mechanical differences most prominently seen in the deltoid muscle and overall JRFs. Further research using this novel integrated model can help guide continued optimization of RSA design and clinical outcomes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Quantum mechanical facets of chemical bonds

International Nuclear Information System (INIS)

Daudel, R.

1976-01-01

To define the concept of bond is both a central problem of quantum chemistry and a difficult one. The concept of bond appeared little by little in the mind of chemists from empirical observations. From the wave-mechanical viewpoint it is not an observable. Therefore there is no precise operator associated with that concept. As a consequence there is not a unique approach to the idea of chemical bond. This is why it is preferred to present various quantum mechanical facets, e.g. the energetic facet, the density facet, the partitioning facet and the functional facet, of that important concept. (Auth.)

The importance of position and path repeatability on force at the knee during six-DOF joint motion.

Science.gov (United States)

Darcy, Shon P; Gil, Jorge E; Woo, Savio L-Y; Debski, Richard E

2009-06-01

Mechanical devices, such as robotic manipulators have been designed to measure joint and ligament function because of their ability to position a diarthrodial joint in six degrees-of-freedom with fidelity. However, the precision and performance of these testing devices vary. Therefore, the objective of this study was to determine the effect of systematic errors in position and path repeatability of two high-payload robotic manipulators (Manipulators 1 and 2) on the resultant forces at the knee. Using a porcine knee, the position and path repeatability of these manipulators were determined during passive flexion-extension with a coordinate measuring machine. The position repeatability of Manipulator 1 was 0.3 mm in position and 0.2 degrees in orientation while Manipulator 2 had a better position repeatability of 0.1 mm in position and 0.1 degrees in orientation throughout the range of positions examined. The corresponding variability in the resultant force at the knee for these assigned positions was 32+/-33 N for Manipulator 1 and 4+/-1 N for Manipulator 2. Furthermore, the repeatability of the trajectory of each manipulator while moving between assigned positions (path repeatability) was 0.8 mm for Manipulator 1 while the path repeatability for Manipulator 2 was improved (0.1 mm). These path discrepancies produced variability in the resultant force at the knee of 44+/-24 and 21+/-8 N, respectively, for Manipulators 1 and 2 primarily due to contact between the articular surfaces of the tibia and femur. Therefore, improved position and path repeatability yields lower variability in the resultant forces at the knee. Although position repeatability has been the most common criteria for evaluating biomechanical testing devices, the current study has clearly demonstrated that path repeatability can have an even larger effect on the variability in resultant force at the knee. Consequently, the repeatability of the path followed by the joint throughout its prescribed

The Variations in Calcaneal Articular Facets In North Indian Population and its Clinical Implication

Directory of Open Access Journals (Sweden)

Seema

2012-01-01

Full Text Available Aims and Objectives- To know the most common type of calcanei in North Indian population and itsclinical importance. There are three articular facets on superior surface of calcaneus- anterior, middle andposterior. Three types of calcanei are noted according to number and arrangement of the articular facets-type A, B and C. Methodology - The present studywas done on 300 dry adult human calcanei of unknownsex taken from Department of Anatomy Sri Guru Ram Das Institute of Medical Sciences and ResearchVallah (Amritsar. Results- In our study Type B was found as the most common type. Type A is the nextmost common. Interpretation- The talocalcaneal joint is important in arthritis and coalition, flat foot, valgus deformity, congenital anomalies and intra articular fractures.

Association of facet tropism and progressive facet arthrosis after lumbar total disc replacement using ProDisc-L.

Science.gov (United States)

Shin, Myung-Hoon; Ryu, Kyeong-Sik; Hur, Jung-Woo; Kim, Jin-Sung; Park, Chun-Kun

2013-08-01

The purpose of this retrospective study was to examine the association of facet tropism and progressive facet arthrosis (PFA) after lumbar total disc replacement (TDR) surgery using ProDisc-L. A total of 51 segments of 42 patients who had undergone lumbar TDR using ProDisc-L between October 2003 and July 2007 and completed minimum 36-month follow-up period were retrospectively reviewed. The changes of facet arthrosis were categorized as non-PFA and PFA group. Comparison between non-PFA and PFA group was made according to age, sex, mean follow-up duration, grade of preoperative facet arthrosis, coronal and sagittal prosthetic position and degree of facet tropism. Multiple logistic regression analysis was also performed to analyze the effect of facet tropism on the progression of facet arthrosis. The mean age at the surgery was 44.43 ± 11.09 years and there were 16 males and 26 females. The mean follow-up period was 53.18 ± 15.79 months. Non-PFA group was composed of 19 levels and PFA group was composed of 32 levels. Age at surgery, sex proportion, mean follow-up period, level of implant, grade of preoperative facet arthrosis and coronal and sagittal prosthetic position were not significantly different between two groups (p = 0.264, 0.433, 0.527, 0.232, 0.926, 0.849 and 0.369, respectively). However, PFA group showed significantly higher degree of facet tropism (7.37 ± 6.46°) than that of non-PFA group (3.51 ± 3.53°) and p value was 0.008. After adjustment for age, sex and coronal and sagittal prosthetic position, multiple logistic regression analysis revealed that facet tropism of more than 5° was the only significant independent predictor of progression of facet arthrosis (odds ratio 5.39, 95 % confidence interval 1.251-19.343, p = 0.023). The data demonstrate that significant higher degree of facet tropism was seen in PFA group compared with non-PFA group and facet tropism of more than 5° had a significant association with PFA after TDR using ProDisc-L.

Operational Maneuver from the Sea and Amphibious Command Relationships: Is It time for a Joint Force Amphibious Component Commander?

National Research Council Canada - National Science Library

Bennett, Michael

2004-01-01

.... In a joint community that is becoming increasingly dependant on the use of functional component commanders in the execution of major operations, the need for a Joint Force Amphibious Component Commander (JFAMCC...

The influence of simulated transversus abdominis muscle force on sacroiliac joint flexibility during asymmetric moment application to the pelvis.

Science.gov (United States)

Gnat, Rafael; Spoor, Kees; Pool-Goudzwaard, Annelies

2015-10-01

The role of so-called local muscle system in motor control of the lower back and pelvis is a subject of ongoing debate. Prevailing beliefs in stabilizing function of this system were recently challenged. This study investigated the impact of in vitro simulated force of transversely oriented fibres of the transversus abdominis muscle (a part of the local system) on flexibility of the sacroiliac joint during asymmetric moment application to the pelvis. In 8 embalmed specimens an incremental moment was applied in the sagittal plane to one innominate with respect to the fixed contralateral innominate. Ranges of motion of the sacroiliac joint were recorded using the Vicon Motion Capture System. Load-deformation curves were plotted and flexibility of the sacroiliac joint was calculated separately for anterior and posterior rotations of the innominate, with and without simulated muscle force. Flexibility of the sacroiliac joint was significantly bigger during anterior rotation of the innominate, as compared to posterior rotation (Anova Psacroiliac joint was demonstrated. Earlier hypotheses suggesting a stiffening influence of this muscle on the pelvis cannot be confirmed. Consistent with previous findings smaller flexibility of the joint recorded during posterior rotation of the innominate may be of clinical importance for physio- and manual therapists. However, major limitations of the study should be acknowledged: in vitro conditions and simulation of only solitary muscle force. Copyright © 2015 Elsevier Ltd. All rights reserved.

The hamatolunate facet: characterization and association with cartilage lesions - magnetic resonance arthrography and anatomic correlation in cadaveric wrists

Energy Technology Data Exchange (ETDEWEB)

Pfirrmann, C.W.A. [Department of Radiology, Veterans Administration Medical Center, 3350 La Jolla Village Dr., San Diego, CA 92161 (United States); Orthopedic University Hospital Balgrist, Department of Radiology, Forchstrasse 340, 8008 Zurich (Switzerland); Theumann, N.H.; Chung, C.B.; Trudell, D.J.; Resnick, D. [Department of Radiology, Veterans Administration Medical Center, 3350 La Jolla Village Dr., San Diego, CA 92161 (United States)

2002-08-01

The objective of this study was to characterize the appearance of the hamatolunate facet using high-resolution magnetic resonance (MR) arthrography in cadavers and to correlate the presence of this anatomic variant with the presence of osteoarthritis in the wrist. High-resolution MR images of 22 cadaveric wrist specimens were obtained after tri-compartmental arthrography. Two readers in consensus analyzed the MR images and recoded the presence or absence of a hamatolunate facet. Geometric characteristics and cartilage and ligament integrity were analyzed. A third reader, who was blinded to the purpose of the study, recorded cartilage lesions of all the bones of the proximal and distal carpal rows. A hamatolunate facet was present in 11 of 22 wrists (50%). The mean coronal size of the lunate facet at the lunate (type II lunate) was 4.5 mm (range, 2-6 mm). The highest frequencies of cartilage lesions were seen in the scapho-trapezio-trapezoid joint (45.5%) and at the proximal pole of the hamate (54.4% and 40.9% for consensus reading/blinded reading, respectively). In cases with a hamatolunate facet, the frequency of cartilage lesions in the proximal pole of the hamate was 81.8% and 63.6% versus 27.3% and 18.2% without such a facet (chi-squared, P=0.01/P=0.03). No correlation of the presence of a hamatolunate facet with interosseous ligament tears or lesions of the triangular fibrocartilage was seen. In conclusion, the hamatolunate facet is a very common anatomic variant. The presence of a hamatolunate facet is associated with cartilage damage in the proximal pole of the hamate. (orig.)

On the relative importance of bending and compression in cervical spine bilateral facet dislocation.

Science.gov (United States)

Nightingale, Roger W; Bass, Cameron R; Myers, Barry S

2018-03-08

Cervical bilateral facet dislocations are among the most devastating spine injuries in terms of likelihood of severe neurological sequelae. More than half of patients with tetraparesis had sustained some form of bilateral facet fracture dislocation. They can occur at any level of the sub-axial cervical spine, but predominate between C5 and C7. The mechanism of these injuries has long been thought to be forceful flexion of the chin towards the chest. This "hyperflexion" hypothesis comports well with intuition and it has become dogma in the clinical literature. However, biomechanical studies of the human cervical spine have had little success in producing this clinically common and devastating injury in a flexion mode of loading. The purpose of this manuscript is to review the clinical and engineering literature on the biomechanics of bilateral facet dislocations and to describe the mechanical reasons for the causal role of compression, and the limited role of head flexion, in producing bilateral facet dislocations. Bilateral facet dislocations have only been produced in experiments where compression is the primary loading mode. To date, no biomechanical study has produced bilateral facet dislocations in a whole spine by bending. Yet the notion that it is primarily a hyper-flexion injury persists in the clinical literature. Compression and compressive buckling are the primary causes of bilateral facet dislocations. It is important to stop using the hyper-flexion nomenclature to describe this class of cervical spines injuries because it may have a detrimental effect on designs for injury prevention. Copyright © 2018 Elsevier Ltd. All rights reserved.

Centralized Command and Control of Theater Missile Defense: The Joint Force Missile Defense Component Coordinator

National Research Council Canada - National Science Library

Bucey, William H

2006-01-01

.... The numerous commands, decentralized command and control, and limited and expensive resources involved in TMD require changes to the joint doctrine in order to provide unity of command and economy of force...

Lumbar Facet Tropism: A Comprehensive Review.

Science.gov (United States)

Alonso, Fernando; Kirkpatrick, Christina M; Jeong, William; Fisahn, Christian; Usman, Sameera; Rustagi, Tarush; Loukas, Marios; Chapman, Jens R; Oskouian, Rod J; Tubbs, R Shane

2017-06-01

Scattered reports exist in the medical literature regarding facet tropism. However, this finding has had mixed conclusions regarding its origin and impact on the normal spine. We performed a literature review of the anatomy, embryology, biomechanics, and pathology related to lumbar facet tropism. Facet tropism is most commonly found at L4-L5 vertebral segments and there is some evidence that this condition may lead to facet degenerative spondylolisthesis, intervertebral disc disease, and other degenerative conditions. Long-term analyses of patients are necessary to elucidate relationships between associated findings and facet tropism. In addition, a universally agreed definition that is more precise should be developed for future investigative studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Morphometric analysis of the cervical facets and the feasibility, safety, and effectiveness of Goel inter-facet spacer distraction technique

Directory of Open Access Journals (Sweden)

Abhidha Shah

2014-01-01

Full Text Available Aim: Quantitative anatomy of the facets of the sub-axial cervical spine was performed. The purpose of the evaluation was to determine the feasibility of insertion of Goel inter-facetal articular spacers in the sub-axial cervical spine. Only few studies detailing the morphometry of the facets are available in the literature. Materials and Methods: Ten cervical vertebrae from C3 to C7 with a total of 20 facets were evaluated by the author. The anatomic parameters studied were the height, width, thickness, shape, orientation, and inclination of each of the superior and inferior facets. The alterations in a number of intervertebral segmental distances were measured before and after spacer insertion. The distance of the inferior facet from the foramen tranversarium, spinal canal, and neural foramina was measured to assess safety of spacer insertion with respect to the vertebral artery and neural structures. Results: The height, width and thickness of the superior facets from C3 to C7 ranged from 6 to 12 mm, 8 to 12 mm, and 2.5 to 6 mm, respectively. The inferior facets had an average height of 10.5 mm, average width of 11.2 mm and average thickness of 3.5 mm. The inclination of the superior facets with respect to the transverse plane ranged from 22° to 45° and that of the inferior facets ranged from 29° to 53°. The distance of the anterior margin of the inferior facet from the posterior border of the foramen transversium ranged from 5 to 7 mm. This distance was maximum at C3 level, then decreased at C4 and remained constant from C5 to C7. Conclusion: This anatomic evaluation aided in understanding the morphology of the cervical facets and the suitability of the cervical facetal articular cavity for insertion of spacers.

Does increased femoral antetorsion predispose to cartilage lesions of the patellofemoral joint?

Science.gov (United States)

Oppermann, Johannes; Bredow, Jan; Wissusek, Boris; Spies, Christian Karl; Boese, Christoph Kolja; Chang, Shi-Min; Eysel, Peer; Dargel, Jens

2017-09-01

The purpose of this study was to investigate whether there was a relationship between femoral neck antetorsion and the presence and pattern of osteoarthritis of the patellofemoral joint. It was hypothesized that an increased femoral neck antetorsion (1) correlates with osteoarthritic changes of the lateral facet of the patellofemoral joint and (2) correlates with an increased lateral trochlear height and a decreased sulcus angle. Seventy-eight formalin-embedded cadaveric lower extremities from thirty-nine subjects with a median age of 74 years (range 60-88) were used. Surrounding soft tissues of the lower limb were removed. The femoral neck antetorsion was measured and referenced to the transepicondylar axis and the posterior condylar line. The height of the medial and lateral facet of the trochlea and the sulcus angle was measured. The location and the degree of patellofemoral cartilage degeneration were recorded. A Pearson's correlation analysis was performed to correlate the femoral neck antetorsion with the measured knee parameters. No significant correlation could be found between the femoral antetorsion and cartilage degeneration of the lateral patellofemoral joint (n.s.), the height of the lateral trochlea (n.s.) and the sulcus angle (n.s.). This study could not document that the femoral neck antetorsion and subsequent internal rotation of the distal femur correlated with the degree of degeneration of the lateral facet of the patellofemoral joint. Clinically, femoral internal rotation may play a minor role in the development of lateral patellofemoral joint degeneration.

Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

Directory of Open Access Journals (Sweden)

Jingtao Lei

2017-03-01

Full Text Available Pneumatic artificial muscles (PAMs have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and dynamic jumping performance. The experimental platform of PAM is conducted, and the static equal pressure experiments are performed to obtain the PAM force model. According to the testing data, parameter identification method is adopted to determine the force model of PAM. A simulation on the position and stiffness control of the knee joint is performed, and the simulation results show the effectiveness of the presented method.

A Joint Force Medical Command is Required to Fix Combat Casualty Care

Science.gov (United States)

2017-10-05

DISTRIBUTION STATEMENT: A Approved for Public Release Distribution is Unlimited The views expressed herein are those of the author(s) and do not...MHS) is required to provide medical operational forces for military and contingency operations while also providing services that maintain a healthy...provide timely support of joint forcible entry or other contingencies requiring rapid response. Further, the complexity and cost of the beneficiary

Mindfulness facets and Big Five personality facets in persons with recurrent depression in remission

NARCIS (Netherlands)

Spinhoven, Philip; Huijbers, Marloes J.; Zheng, Yixia; Ormel, Johan; Speckens, Anne E. M.

2017-01-01

Studies examining mindfulness in relation to personality traits have been mainly conducted in non-clinical samples and resulted in mixed findings. The present cross-sectional study examined which mindfulness facets are most strongly associated with Big Five personality domains and facets implicated

The value of SPECT bone scans in diagnosis of patients with zygapophseal joint pain

International Nuclear Information System (INIS)

Hu Jiajia; Liang Yu; Li Biao; Zhu Chengmo; Chen Gang; Wang Chao; Tian Weijia; Qu Liumin

2008-01-01

Objective: Bone scintigraphy with SPECT of the lumbar spine allows identification of lesions not seen with planar imaging, in patients with chronic low back pain. The aim of this study was to investigate the value of SPECT bone scans in diagnosis of patients with zygapophyseal joint pain. Methods: Thirty-five consecutive patients in Ruijin hospital from July 2006 to March 2007 with low back pain were en- rolled. All patients underwent bone scintigraphy with SPECT. According to the results of SPECT, patients with isotope-uptake joints received injections at the levels where abnormalities were identified on the scan. Patients with negative scans received other treatment (conservative treatment or surgery) but not facet joint injection. Clinical records were collected at 1-, 3-, and 6-month in SPECT-positive group after their initial treatment. And the SPECT-negative group were followed up at 6-month after therapy. Statistical analysis was performed with SPSS 10.0. Patients with SPECT-positive and -negative results were performed with the grouped t-test. Visual analog scales (VAS) were with the paired t-test used in patients with positive scans at before and after treatment. Results: Fifteen cases had facetal uptake of isotope on SPECT bone scans. After facet joint injection, 85.7% patients (12/14, 1 patient was excluded for operation) had improvement in pain score at 1-month, 78.6% (11/14) at 3-month, and 50.0% (7/14) at 6-month. Of 20 negative cases, 3 were treated by surgery and 17 by conservative treatment. All 20 cases were followed up for 6 months and 70.0% (14/20) had long time pain relief. Conclusion: SPECT bone scans are helpful to identify patients with low back pain who would benefit from facet joint injections. (authors)

Summary of 21st joint EU-US transport task force workshop.

Czech Academy of Sciences Publication Activity Database

Mantica, P.; Bourdelle, C.; Camenen, Y.; Dejarnac, Renaud; Evans, T.; Görler, T.; Hillesheim, J.; Idomura, Y.; Jakubowski, M.; Ricci, P.; White, A.

2017-01-01

Roč. 57, č. 8 (2017), č. článku 087001. ISSN 0029-5515. [Joint EU-US Transport Task Force workshop/21./. Leysin, 05.09.2016-08.09.2016] EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : transport * confinement * turbulence Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.307, year: 2016 http://iopscience.iop.org/article/10.1088/1741-4326/aa753f/meta

A folk-psychological ranking of personality facets

Directory of Open Access Journals (Sweden)

Eka Roivainen

2016-10-01

Full Text Available Background Which personality facets should a general personality test measure? No consensus exists on the facet structure of personality, the nature of facets, or the correct method of identifying the most significant facets. However, it can be hypothesized (the lexical hypothesis that high frequency personality describing words more likely represent important personality facets and rarely used words refer to less significant aspects of personality. Participants and procedure A ranking of personality facets was performed by studying the frequency of the use of popular personality adjectives in causal clauses (because he is a kind person on the Internet and in books as attributes of the word person (kind person. Results In Study 1, the 40 most frequently used adjectives had a cumulative usage frequency equal to that of the rest of the 295 terms studied. When terms with a higher-ranking dictionary synonym or antonym were eliminated, 23 terms remained, which represent 23 different facets. In Study 2, clusters of synonymous terms were examined. Within the top 30 clusters, personality terms were used 855 times compared to 240 for the 70 lower-ranking clusters. Conclusions It is hypothesized that personality facets represented by the top-ranking terms and clusters of terms are important and impactful independent of their correlation with abstract underlying personality factors (five/six factor models. Compared to hierarchical personality models, lists of important facets probably better cover those aspects of personality that are situated between the five or six major domains.

The effect of glenosphere diameter in reverse shoulder arthroplasty on muscle force, joint load, and range of motion.

Science.gov (United States)

Langohr, G Daniel G; Giles, Joshua W; Athwal, George S; Johnson, James A

2015-06-01

Little is known about the effects of glenosphere diameter on shoulder joint loads. The purpose of this biomechanical study was to investigate the effects of glenosphere diameter on joint load, load angle, and total deltoid force required for active abduction and range of motion in internal/external rotation and abduction. A custom, instrumented reverse shoulder arthroplasty implant system capable of measuring joint load and varying glenosphere diameter (38 and 42 mm) and glenoid offset (neutral and lateral) was implanted in 6 cadaveric shoulders to provide at least 80% power for all variables. A shoulder motion simulator was used to produce active glenohumeral and scapulothoracic motion. All implant configurations were tested with active and passive motion with joint kinematics, loads, and moments recorded. At neutral and lateralized glenosphere positions, increasing diameter significantly increased joint load (+12 ± 21 N and +6 ± 9 N; P  .8). Passive internal rotation was reduced with increased diameter at both neutral and lateralized glenosphere positions (-6° ± 6° and -12° ± 6°; P  .05). At neutral glenosphere position, increasing diameter increased the maximum angles of both adduction (+1° ± 1°; P = .03) and abduction (+8° ± 9°; P < .05). Lateralization also increased abduction range of motion compared with neutral (P < .01). Although increasing glenosphere diameter significantly increased joint load and deltoid force, the clinical impact of these changes is presently unclear. Internal rotation, however, was reduced, which contradicts previous bone modeling studies, which we postulate is due to increased posterior capsular tension as it is forced to wrap around a larger 42 mm implant assembly. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Gemstone Grinding Process Improvement by using Impedance Force Control

Directory of Open Access Journals (Sweden)

Hamprommarat Chumpol

2015-01-01

Full Text Available Chula Automatic Faceting Machine has been developed by The Advance Manufacturing Research Lab, Chulalongkorn University to support Thailand Gems-Industry. The machine has high precision motion control by using position and force control. A contact stiffness model is used to estimate grinding force. Although polished gems from the Faceting Machine have uniform size and acceptable shape, the force of the grinding and polishing process cannot be maintain constant and has some fluctuation due to indirect force control. Therefor this research work propose a new controller for this process based on an impedance direct force control to improve the gemstone grinding performance during polishing process. The grinding force can be measured through motor current. The results show that the polished gems by using impedance direct force control can maintain uniform size as well as good shape and high quality surface.

Joint Operation Planning

National Research Council Canada - National Science Library

2006-01-01

.... It sets forth joint doctrine to govern the joint operation planning activities and performance of the Armed Forces of the United States in joint operations, and provides the joint doctrinal basis...

FACET Emittance Growth

Energy Technology Data Exchange (ETDEWEB)

Frederico, J; Hogan, M.J.; Nosochkov, Y.; Litos, M.D.; Raubenheimer, T.; /SLAC

2011-04-05

FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to {approx}20 {micro}m long and {approx}10 {micro}m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.

FACET Emittance Growth

International Nuclear Information System (INIS)

Frederico, Joel

2011-01-01

FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to ∼20 (micro)m long and ∼10 (micro)m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.

(113) Facets of Si-Ge/Si Islands; Atomic Scale Simulation

Science.gov (United States)

Kassem, Hassan

We have studied, by computer simulation, some static and vibrationnal proprieties of SiGe/Si islands. We have used a Valence Force Field combined to Monte Carlo technique to study the growth of Ge and SiGe on (001)Si substrates. We have focalised on the case of large pyramidal islands presenting (113) facets on the free (001)Si surface with various non uniform composition inside the islands. The deformation inside the islands and Raman spectroscopy are discussed.

Bilateral locked facets in the thoracic spine

NARCIS (Netherlands)

M.H.A. Willems; Braakman, R. (Reinder); B. van Linge (Bert)

1984-01-01

textabstractTwo cases of traumatic bilateral locked facets in the thoracic spine are reported. Both patients had only minor neurological signs. They both made a full neurological recovery after surgical reduction of the locked facets. Bilateral locked facets are very uncommon in the thoracic spine.

Effect of Chord Splice Joints on Force Distribution and Deformations in Trusses with Punched Metal Plate Fasteners

DEFF Research Database (Denmark)

Ellegaard, Peter

2007-01-01

The span of roof trusses with punched metal plate fasteners (nail plates) makes it often necessary to use splice joints in the top and bottom chords. In the finite element models used for design of the trusses these splice joints are normally assumed to be either rotationally stiff or pinned....... Timber-to-timber contact and non-linear elastic behaviour are included in the model. Results from tests with joints under fourpoint bending are compared with predictions given by TrussLab, and a good agreement is found. Splice joints in trusses with nail plates may be assumed to be rotationally stiff...... if their deformation has no significant effect upon the distribution of member forces according to Eurocode 5. Two simple guidelines for the design and location of splice joints are given in Eurocode 5 for treating the splice joints as rotationally stiff. The reasonability of these guidelines and the influence...

3D Model Optimization of Four-Facet Drill for 3D Drilling Simulation

Directory of Open Access Journals (Sweden)

Buranský Ivan

2016-09-01

Full Text Available The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

FACET CLASSIFICATIONS OF E-LEARNING TOOLS

Directory of Open Access Journals (Sweden)

Olena Yu. Balalaieva

2013-12-01

Full Text Available The article deals with the classification of e-learning tools based on the facet method, which suggests the separation of the parallel set of objects into independent classification groups; at the same time it is not assumed rigid classification structure and pre-built finite groups classification groups are formed by a combination of values taken from the relevant facets. An attempt to systematize the existing classification of e-learning tools from the standpoint of classification theory is made for the first time. Modern Ukrainian and foreign facet classifications of e-learning tools are described; their positive and negative features compared to classifications based on a hierarchical method are analyzed. The original author's facet classification of e-learning tools is proposed.

Antero-medial approach to the wrist: anatomic basis and new application in cases of fracture of the lunate facet.

Science.gov (United States)

Uzel, A-P; Bulla, A; Laurent-Joye, M; Caix, P

2011-08-01

The Henry approach is the classical anterolateral surgical exposure of the volar aspect of the distal radius. This approach does not allow good access to the medial side of the volar distal radius (lunate facet) and the distal radio-ulnar joint, unless it is extended proximally, retracting the tendons and the median nerve medially, which can cause some trauma. The purpose of our study was to investigate the anatomic basis and to outline the advantages of the unusual anteromedial approach, reporting our experience in the treatment of 4 distal radius fractures, with a 90° or 180° twist of the lunate facet, and 10 wrist dissections on cadavers. The average follow-up was 68.8 months (range 18 to 115 months). In our series, this approach did not cause any nerve injuries or any sensory loss of the distal forearm and the palm. All the fractures of the lunate facet and of the radial styloid process healed. One patient with an ulnar styloid process fracture associated showed pseudarthrosis, but with no instability of the distal radio-ulnar joint or pain on the ulnar side. Using the criteria of Green and O'Brien, modified by Cooney, the results were: excellent in two cases, good in one case, and average in another. The evaluation of arthritis according to Knirk and Jupiter's classification showed grade 0 in three cases and grade 3 in one case with osteochondral sclerosis. We showed that the anteromedial approach is reliable and convenient in the case of fractures situated in the antero-medial portion of the radius, for the double objective of reducing the fracture under direct control and checking the congruence of the distal radio-ulnar joint.

A faceted eye on intellectual giftedness: Examining the personality of gifted students using FFM domains and facets

Directory of Open Access Journals (Sweden)

Altaras-Dimitrijević Ana

2012-01-01

Full Text Available The study examines the personality profile of gifted vs. average-ability students from the perspective of the FFM. The issue was approached by (1 reviewing the literature for well-established personality characteristics of the gifted, (2 establishing correspondences between these traits and FFM domains/facets, and (3 formulating a domain and a facet-level model which were hypothesized to discriminate significantly between gifted and nongifted students. The domain-level model consisted of Openness and Agreeableness. The facet-level model included 14 traits: Anxiety, Impulsiveness, Gregariousness, Assertiveness, Fantasy, Feelings, Aesthetics, Ideas, Compliance, Modesty, Tendermindedness, Order, Achievement, and Deliberation. The models were tested on three samples (N1=515 high-school students, 155 gifted; N2=132 psychology students, 28 gifted; N3=443 psychology students, 91 gifted. Results indicate that the domain-level model does not discriminate significantly between gifted and nongifted students in each sample, whereas the proposed 14-facet model yields a significant discrimination across all samples. The latter model may be further adjusted by removing facets which proved inconsistent or unsubstantial in distinguishing between the two groups. This yields a 7-facet discriminant function, which is also significant across samples, indicating that gifted students are consistently distinguished by a combination of high Ideas, Fantasy, Aesthetics, and Assertiveness, but low Gregariuosness, Modesty, and Tendermindeness. Educational implications and limitations are discussed. [Projekat Ministarstva nauke Republike Srbije, br. 179018

The growth of faceted/nonfaceted eutectics

International Nuclear Information System (INIS)

Suchtelen, J. van

1976-01-01

This paper is concerned with the unidirectional solidification of eutectic melts in which one of the phases has a faceted, the other a nonfaceted solid-liquid interface. The occurrence of complex microstructures in such eutectics is explained as a growth phenomenon. The essential condition for the occurrence of such structures is a non-isothermal solid-liquid interface, developing into a faceted-cellular structure. The faceted shape of the cells is imposed by the faceted component of the eutectic. Breakdown to such a cellular structure occurs not only in constitutional-supercooling conditions, but under any circumstances, the cellular period being a function of growth velocity, temperature gradient etc. The two-phase morphology of the eutectic structure is discussed in terms of the relative magnitude of the periods of the cellular and of the eutectic structure. (orig.) [de

Proposal plan of classification faceted for federal universities

Directory of Open Access Journals (Sweden)

Renata Santos Brandão

2017-09-01

Full Text Available This study aims to present a faceted classification plan for the archival management of documents in the federal universities of Brazil. For this, was done a literature review on the archival management in Brazil, the types of classification plans and the theory of the Ranganathan faceted classification, through searches in databases in the areas of Librarianship and Archivology. It was identified the classification plan used in the Federal Institutions of Higher Education to represent the functional facet and created the structural classification plan to represent the structural facet. The two classification plans were inserted into a digital repository management system to give rise to the faceted classification plan. The system used was Tainacan, free software wordpress-based used in digital document management. The developed faceted classification plan allows the user to choose and even combine the way to look for the information that guarantees agreater efficiency in the information retrieval.

Work functions and surface charges at metallic facet edges

International Nuclear Information System (INIS)

Fall, C.J.; Binggeli, N.; Baldereschi, A.

2002-04-01

The electronic charge densities and work functions at sharp metallic facet edges are determined from ab initio calculations, combined with macroscopic averaging techniques. In particular, we examine how two different work functions coexist at close range near edges between inequivalent facets. The surface ionic relaxation at facet edges is shown to influence appreciably the local electrostatic potential in the vacuum. Various edges between Al(100) and Al(111) facets are studied, as well as between Na(110) facets. We also develop a model of electronic surface dipoles, which accounts for the surface charge transfer between inequivalent facets, and which allows us to predict the influence of the shape and size of a macroscopic crystal on its work functions. (author)

Scalable Faceted Ranking in Tagging Systems

Science.gov (United States)

Orlicki, José I.; Alvarez-Hamelin, J. Ignacio; Fierens, Pablo I.

Nowadays, web collaborative tagging systems which allow users to upload, comment on and recommend contents, are growing. Such systems can be represented as graphs where nodes correspond to users and tagged-links to recommendations. In this paper we analyze the problem of computing a ranking of users with respect to a facet described as a set of tags. A straightforward solution is to compute a PageRank-like algorithm on a facet-related graph, but it is not feasible for online computation. We propose an alternative: (i) a ranking for each tag is computed offline on the basis of tag-related subgraphs; (ii) a faceted order is generated online by merging rankings corresponding to all the tags in the facet. Based on the graph analysis of YouTube and Flickr, we show that step (i) is scalable. We also present efficient algorithms for step (ii), which are evaluated by comparing their results with two gold standards.

The Effects of Cryotherapy on Knee Joint Position Sense and Force Production Sense in Healthy Individuals

Directory of Open Access Journals (Sweden)

Furmanek Mariusz P.

2018-03-01

Full Text Available The proprioceptive information received from mechanoreceptors is potentially responsible for controlling the joint position and force differentiation. However, it is unknown whether cryotherapy influences this complex mechanism. Previously reported results are not universally conclusive and sometimes even contradictory. The main objective of this study was to investigate the impact of local cryotherapy on knee joint position sense (JPS and force production sense (FPS. The study group consisted of 55 healthy participants (age: 21 ± 2 years, body height: 171.2 ± 9 cm, body mass: 63.3 ± 12 kg, BMI: 21.5 ± 2.6. Local cooling was achieved with the use of gel-packs cooled to -2 ± 2.5°C and applied simultaneously over the knee joint and the quadriceps femoris muscle for 20 minutes. JPS and FPS were evaluated using the Biodex System 4 Pro apparatus. Repeated measures analysis of variance (ANOVA did not show any statistically significant changes of the JPS and FPS under application of cryotherapy for all analyzed variables: the JPS’s absolute error (p = 0.976, its relative error (p = 0.295, and its variable error (p = 0.489; the FPS’s absolute error (p = 0.688, its relative error (p = 0.193, and its variable error (p = 0.123. The results indicate that local cooling does not affect proprioceptive acuity of the healthy knee joint. They also suggest that local limited cooling before physical activity at low velocity did not present health or injury risk in this particular study group.

The Effects of Cryotherapy on Knee Joint Position Sense and Force Production Sense in Healthy Individuals

Science.gov (United States)

Furmanek, Mariusz P.; Słomka, Kajetan J.; Sobiesiak, Andrzej; Rzepko, Marian; Juras, Grzegorz

2018-01-01

Abstract The proprioceptive information received from mechanoreceptors is potentially responsible for controlling the joint position and force differentiation. However, it is unknown whether cryotherapy influences this complex mechanism. Previously reported results are not universally conclusive and sometimes even contradictory. The main objective of this study was to investigate the impact of local cryotherapy on knee joint position sense (JPS) and force production sense (FPS). The study group consisted of 55 healthy participants (age: 21 ± 2 years, body height: 171.2 ± 9 cm, body mass: 63.3 ± 12 kg, BMI: 21.5 ± 2.6). Local cooling was achieved with the use of gel-packs cooled to -2 ± 2.5°C and applied simultaneously over the knee joint and the quadriceps femoris muscle for 20 minutes. JPS and FPS were evaluated using the Biodex System 4 Pro apparatus. Repeated measures analysis of variance (ANOVA) did not show any statistically significant changes of the JPS and FPS under application of cryotherapy for all analyzed variables: the JPS’s absolute error (p = 0.976), its relative error (p = 0.295), and its variable error (p = 0.489); the FPS’s absolute error (p = 0.688), its relative error (p = 0.193), and its variable error (p = 0.123). The results indicate that local cooling does not affect proprioceptive acuity of the healthy knee joint. They also suggest that local limited cooling before physical activity at low velocity did not present health or injury risk in this particular study group. PMID:29599858

Objective Assessment of Joint Stiffness: A Clinically Oriented Hardware and Software Device with an Application to the Shoulder Joint.

Science.gov (United States)

McQuade, Kevin; Price, Robert; Liu, Nelson; Ciol, Marcia A

2012-08-30

Examination of articular joints is largely based on subjective assessment of the "end-feel" of the joint in response to manually applied forces at different joint orientations. This technical report aims to describe the development of an objective method to examine joints in general, with specific application to the shoulder, and suitable for clinical use. We adapted existing hardware and developed laptop-based software to objectively record the force/displacement behavior of the glenohumeral joint during three common manual joint examination tests with the arm in six positions. An electromagnetic tracking system recorded three-dimensional positions of sensors attached to a clinician examiner and a patient. A hand-held force transducer recorded manually applied translational forces. The force and joint displacement were time-synchronized and the joint stiffness was calculated as a quantitative representation of the joint "end-feel." A methodology and specific system checks were developed to enhance clinical testing reproducibility and precision. The device and testing protocol were tested on 31 subjects (15 with healthy shoulders, and 16 with a variety of shoulder impairments). Results describe the stiffness responses, and demonstrate the feasibility of using the device and methods in clinical settings.

Joint force protection advanced security system (JFPASS) "the future of force protection: integrate and automate"

Science.gov (United States)

Lama, Carlos E.; Fagan, Joe E.

2009-09-01

The United States Department of Defense (DoD) defines 'force protection' as "preventive measures taken to mitigate hostile actions against DoD personnel (to include family members), resources, facilities, and critical information." Advanced technologies enable significant improvements in automating and distributing situation awareness, optimizing operator time, and improving sustainability, which enhance protection and lower costs. The JFPASS Joint Capability Technology Demonstration (JCTD) demonstrates a force protection environment that combines physical security and Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE) defense through the application of integrated command and control and data fusion. The JFPASS JCTD provides a layered approach to force protection by integrating traditional sensors used in physical security, such as video cameras, battlefield surveillance radars, unmanned and unattended ground sensors. The optimization of human participation and automation of processes is achieved by employment of unmanned ground vehicles, along with remotely operated lethal and less-than-lethal weapon systems. These capabilities are integrated via a tailorable, user-defined common operational picture display through a data fusion engine operating in the background. The combined systems automate the screening of alarms, manage the information displays, and provide assessment and response measures. The data fusion engine links disparate sensors and systems, and applies tailored logic to focus the assessment of events. It enables timely responses by providing the user with automated and semi-automated decision support tools. The JFPASS JCTD uses standard communication/data exchange protocols, which allow the system to incorporate future sensor technologies or communication networks, while maintaining the ability to communicate with legacy or existing systems.

SLAC Linac Preparations for FACET

International Nuclear Information System (INIS)

Erickson, Roger

2011-01-01

The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.

Framework Application for Core Edge Transport Simulation (FACETS)

Energy Technology Data Exchange (ETDEWEB)

Malony, Allen D; Shende, Sameer S; Huck, Kevin A; Mr. Alan Morris, and Mr. Wyatt Spear

2012-03-14

The goal of the FACETS project (Framework Application for Core-Edge Transport Simulations) was to provide a multiphysics, parallel framework application (FACETS) that will enable whole-device modeling for the U.S. fusion program, to provide the modeling infrastructure needed for ITER, the next step fusion confinement device. Through use of modern computational methods, including component technology and object oriented design, FACETS is able to switch from one model to another for a given aspect of the physics in a flexible manner. This enables use of simplified models for rapid turnaround or high-fidelity models that can take advantage of the largest supercomputer hardware. FACETS does so in a heterogeneous parallel context, where different parts of the application execute in parallel by utilizing task farming, domain decomposition, and/or pipelining as needed and applicable. ParaTools, Inc. was tasked with supporting the performance analysis and tuning of the FACETS components and framework in order to achieve the parallel scaling goals of the project. The TAU Performance System® was used for instrumentation, measurement, archiving, and profile / tracing analysis. ParaTools, Inc. also assisted in FACETS performance engineering efforts. Through the use of the TAU Performance System, ParaTools provided instrumentation, measurement, analysis and archival support for the FACETS project. Performance optimization of key components has yielded significant performance speedups. TAU was integrated into the FACETS build for both the full coupled application and the UEDGE component. The performance database provided archival storage of the performance regression testing data generated by the project, and helped to track improvements in the software development.

Force sharing and other collaborative strategies in a dyadic force perception task.

Science.gov (United States)

Tatti, Fabio; Baud-Bovy, Gabriel

2018-01-01

When several persons perform a physical task jointly, such as transporting an object together, the interaction force that each person experiences is the sum of the forces applied by all other persons on the same object. Therefore, there is a fundamental ambiguity about the origin of the force that each person experiences. This study investigated the ability of a dyad (two persons) to identify the direction of a small force produced by a haptic device and applied to a jointly held object. In this particular task, the dyad might split the force produced by the haptic device (the external force) in an infinite number of ways, depending on how the two partners interacted physically. A major objective of this study was to understand how the two partners coordinated their action to perceive the direction of the third force that was applied to the jointly held object. This study included a condition where each participant responded independently and another one where the two participants had to agree upon a single negotiated response. The results showed a broad range of behaviors. In general, the external force was not split in a way that would maximize the joint performance. In fact, the external force was often split very unequally, leaving one person without information about the external force. However, the performance was better than expected in this case, which led to the discovery of an unanticipated strategy whereby the person who took all the force transmitted this information to the partner by moving the jointly held object. When the dyad could negotiate the response, we found that the participant with less force information tended to switch his or her response more often.

The independent effects of speed and propulsive force on joint power generation in walking.

Science.gov (United States)

Browne, Michael G; Franz, Jason R

2017-04-11

Walking speed is modulated using propulsive forces (F P ) during push-off and both preferred speed and F P decrease with aging. However, even prior to walking slower, reduced F P may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time F P measurements to decouple and investigate the interaction between joint-level coordination, whole-body F P , and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9-1.3m/s). We immediately calculated the average F P from each speed. Subjects then walked at 1.3m/s while completing a series of biofeedback trials with instructions to match their instantaneous F P to their averaged F P from slower speeds. Walking slower decreased F P and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced F P , not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body F P , and walking speed in our aging population. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimation of Joint Forces and Moments for the In-Run and Take-Off in Ski Jumping Based on Measurements with Wearable Inertial Sensors

Directory of Open Access Journals (Sweden)

Grega Logar

2015-05-01

Full Text Available This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton–Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers’ body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill.

Estimation of joint forces and moments for the in-run and take-off in ski jumping based on measurements with wearable inertial sensors.

Science.gov (United States)

Logar, Grega; Munih, Marko

2015-05-13

This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton-Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers' body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill.

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint.

Science.gov (United States)

Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan Rt

2017-01-01

Data about a muscle's fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep

Output Force Enhancement of Scratch Drive Actuator in Low-Voltage Region by Using Flexible Joint

Directory of Open Access Journals (Sweden)

Shawn CHEN

2010-04-01

Full Text Available Here a low-voltage scratch drive actuator (LVSDA is proposed by incorporating flexible joint into the conventional SDA to improve performance in low-voltage region. Experimental results show that, at the same total plate length of 80 mm and width of 65 mm, the proposed LVSDA can be actuated as low as 40 V, much lower than 80 V, the minimum required input voltage of the conventional SDA. From finite element analysis by CosmosWorks, yielding effect is found to be a critical factor. Before yielding, LVSDA can provide better performance than SDA at the same input voltage. However, the yielding stress in flexible joint would limit the achievable maximum output force in high-voltage region. By varying joint length, width, or location, LVSDA is shown to be operated in low-voltage region where the conventional SDA can not be operated, and can still provide comparable performance as SDA in high-voltage region.

Psychophysical testing of visual prosthetic devices: a call to establish a multi-national joint task force

Science.gov (United States)

Rizzo, Joseph F., III; Ayton, Lauren N.

2014-04-01

Recent advances in the field of visual prostheses, as showcased in this special feature of Journal of Neural Engineering , have led to promising results from clinical trials of a number of devices. However, as noted by these groups there are many challenges involved in assessing vision of people with profound vision loss. As such, it is important that there is consistency in the methodology and reporting standards for clinical trials of visual prostheses and, indeed, the broader vision restoration research field. Two visual prosthesis research groups, the Boston Retinal Implant Project (BRIP) and Bionic Vision Australia (BVA), have agreed to work cooperatively to establish a multi-national Joint Task Force. The aim of this Task Force will be to develop a consensus statement to guide the methods used to conduct and report psychophysical and clinical results of humans who receive visual prosthetic devices. The overarching goal is to ensure maximum benefit to the implant recipients, not only in the outcomes of the visual prosthesis itself, but also in enabling them to obtain accurate information about this research with ease. The aspiration to develop a Joint Task Force was first promulgated at the inaugural 'The Eye and the Chip' meeting in September 2000. This meeting was established to promote the development of the visual prosthetic field by applying the principles of inclusiveness, openness, and collegiality among the growing body of researchers in this field. These same principles underlie the intent of this Joint Task Force to enhance the quality of psychophysical research within our community. Despite prior efforts, a critical mass of interested parties could not congeal. Renewed interest for developing joint guidelines has developed recently because of a growing awareness of the challenges of obtaining reliable measurements of visual function in patients who are severely visually impaired (in whom testing is inherently noisy), and of the importance of

Preamble to marine microbiology: Facets and opportunities

Digital Repository Service at National Institute of Oceanography (India)

Ramaiah, N.

The book titled 'Marine Microbiology: Facets & Opportunities' is an attempt to bring together some facets of marine microbiology as have been made out by many contemporaries in particular from the tropical marine regions. There are 18 contributed...

Cervical endplate and facet arthrosis: an anatomic study of cadaveric specimens.

Science.gov (United States)

Master, Daniel L; Toy, Jason O; Eubanks, Jason D; Ahn, Nicholas U

2012-10-01

An anatomic, epidemiologic study of cervical endplate and facet arthrosis in cadaveric spines. To determine the prevalence of cervical endplate and facet arthrosis and the relationship between these 2 entities in a large population sample. Cervical endplate and facet arthrosis are common radiographic findings, which have both been linked to pain. However, the prevalence and relationship between cervical endplate and facet arthrosis has not been clearly defined. The cervical vertebrae from 234 cadaveric spines were examined by a single investigator for evidence of endplate and facet arthrosis. Arthrosis at each endplate and facet was graded on a continuum from 0 to IV. Race, age at death, and sex of each specimen were also recorded. Stepwise multiple linear regression was used to analyze any association between race, age, sex, endplate arthrosis, and facet arthrosis. Factors with P values arthrosis severity scores among patients within the same decades of life. Concurrent cervical endplate and facet arthrosis was present in 77% of the study population. Stepwise multiple linear regression revealed significant (Parthrosis and between age and facet arthrosis. Race and sex did not correlate with facet arthrosis. In addition, patients in age groups 30 to 39, 40 to 49, 50 to 59, 60 to 69, 70 to 79, and 80 to 89 demonstrated more severe (Parthrosis in comparison with facet arthrosis. Concurrent cervical endplate and facet arthrosis is a common condition. Cervical endplate arthrosis and advancing age are associated with cervical facet arthrosis independent of race and sex. Cervical endplate arthrosis precedes facet arthrosis.

Analysis of movement axes of the ankle and subtalar joints: relationship with the articular surfaces of the talus.

Science.gov (United States)

Cho, Ho-Jung; Kwak, Dai-Soon; Kim, In-Beom

2014-10-01

Bone shape varies among human populations, and in the case of articular joints, the shape of the articulating surfaces strongly influences joint movement. In this study, we aimed to analyse the axes of the talocrural and subtalar joints, using the talar articular surface method, and compare these results with those of the previous studies. We used three-dimensional reconstruction models of tali among Korean individuals. The axes of the talocrural and subtalar joints were calculated by using the least-square sphere fitting method, and the principal axis was used for reference coordination. The shape of the talus was classified based on the shape of its anterior, middle, and posterior calcaneal facets, and the talar shape was compared with the movement axes. The movement axes did not differ according to the type of calcaneal facets of the talus. Interestingly, we also noted that the axes of the talocrural and subtalar joints in this study differed significantly from those reported in the previous studies; these differences may be due to variations in the shape of the bones. © IMechE 2014.

Force sharing and other collaborative strategies in a dyadic force perception task

Science.gov (United States)

Tatti, Fabio

2018-01-01

When several persons perform a physical task jointly, such as transporting an object together, the interaction force that each person experiences is the sum of the forces applied by all other persons on the same object. Therefore, there is a fundamental ambiguity about the origin of the force that each person experiences. This study investigated the ability of a dyad (two persons) to identify the direction of a small force produced by a haptic device and applied to a jointly held object. In this particular task, the dyad might split the force produced by the haptic device (the external force) in an infinite number of ways, depending on how the two partners interacted physically. A major objective of this study was to understand how the two partners coordinated their action to perceive the direction of the third force that was applied to the jointly held object. This study included a condition where each participant responded independently and another one where the two participants had to agree upon a single negotiated response. The results showed a broad range of behaviors. In general, the external force was not split in a way that would maximize the joint performance. In fact, the external force was often split very unequally, leaving one person without information about the external force. However, the performance was better than expected in this case, which led to the discovery of an unanticipated strategy whereby the person who took all the force transmitted this information to the partner by moving the jointly held object. When the dyad could negotiate the response, we found that the participant with less force information tended to switch his or her response more often. PMID:29474433

Concurrent, parallel, multiphysics coupling in the FACETS project

Energy Technology Data Exchange (ETDEWEB)

Cary, J R; Carlsson, J A; Hakim, A H; Kruger, S E; Miah, M; Pletzer, A; Shasharina, S [Tech-X Corporation, 5621 Arapahoe Avenue, Suite A, Boulder, CO 80303 (United States); Candy, J; Groebner, R J [General Atomics (United States); Cobb, J; Fahey, M R [Oak Ridge National Laboratory (United States); Cohen, R H; Epperly, T [Lawrence Livermore National Laboratory (United States); Estep, D J [Colorado State University (United States); Krasheninnikov, S [University of California at San Diego (United States); Malony, A D [ParaTools, Inc (United States); McCune, D C [Princeton Plasma Physics Laboratory (United States); McInnes, L; Balay, S [Argonne National Laboratory (United States); Pankin, A, E-mail: cary@txcorp.co [Lehigh University (United States)

2009-07-01

FACETS (Framework Application for Core-Edge Transport Simulations), is now in its third year. The FACETS team has developed a framework for concurrent coupling of parallel computational physics for use on Leadership Class Facilities (LCFs). In the course of the last year, FACETS has tackled many of the difficult problems of moving to parallel, integrated modeling by developing algorithms for coupled systems, extracting legacy applications as components, modifying them to run on LCFs, and improving the performance of all components. The development of FACETS abides by rigorous engineering standards, including cross platform build and test systems, with the latter covering regression, performance, and visualization. In addition, FACETS has demonstrated the ability to incorporate full turbulence computations for the highest fidelity transport computations. Early indications are that the framework, using such computations, scales to multiple tens of thousands of processors. These accomplishments were a result of an interdisciplinary collaboration among computational physics, computer scientists and applied mathematicians on the team.

Prediction of medial and lateral contact force of the knee joint during normal and turning gait after total knee replacement.

Science.gov (United States)

Purevsuren, Tserenchimed; Dorj, Ariunzaya; Kim, Kyungsoo; Kim, Yoon Hyuk

2016-04-01

The computational modeling approach has commonly been used to predict knee joint contact forces, muscle forces, and ligament loads during activities of daily living. Knowledge of these forces has several potential applications, for example, within design of equipment to protect the knee joint from injury and to plan adequate rehabilitation protocols, although clinical applications of computational models are still evolving and one of the limiting factors is model validation. The objective of this study was to extend previous modeling technique and to improve the validity of the model prediction using publicly available data set of the fifth "Grand Challenge Competition to Predict In Vivo Knee Loads." A two-stage modeling approach, which combines conventional inverse dynamic analysis (the first stage) with a multi-body subject-specific lower limb model (the second stage), was used to calculate medial and lateral compartment contact forces. The validation was performed by direct comparison of model predictions and experimental measurement of medial and lateral compartment contact forces during normal and turning gait. The model predictions of both medial and lateral contact forces showed strong correlations with experimental measurements in normal gait (r = 0.75 and 0.71) and in turning gait trials (r = 0.86 and 0.72), even though the current technique over-estimated medial compartment contact forces in swing phase. The correlation coefficient, Sprague and Geers metrics, and root mean squared error indicated that the lateral contact forces were predicted better than medial contact forces in comparison with the experimental measurements during both normal and turning gait trials. © IMechE 2016.

Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

Science.gov (United States)

Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

2014-08-01

Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

Cervical facet oedema: prevalence, correlation to symptoms, and follow-up imaging

International Nuclear Information System (INIS)

Nevalainen, M.T.; Foran, P.J.; Roedl, J.B.; Zoga, A.C.; Morrison, W.B.

2016-01-01

Aim: To evaluate the prevalence of cervical facet oedema in patients referred for magnetic resonance imaging (MRI) to investigate neck pain and/or radiculopathy, and to investigate whether there is a correlation between the presence of oedema and patients' symptoms. Materials and methods: A retrospective report review of 1885 patients undergoing cervical spine MRI between July 2008 and June 2015 was performed. Exclusion criteria included acute trauma, surgery, neoplastic disease, or infection in the cervical spine. One hundred and seventy-three MRI studies with cervical facet oedema were evaluated by each of the two radiologists. In these patients, the grade of bone marrow oedema (BMO) and corresponding neuroforaminal narrowing at the cervical facets was assessed. Correlation with symptoms was performed based on pre-MRI questionnaire. Results: The prevalence of cervical facet oedema was 9%; the most commonly affected levels were C3–4, C4–5, and C2–3. A total of 202 cervical facets were evaluated: mild BMO was seen in 35%, moderate in 41%, and severe in 24% of cases. Surrounding soft-tissue oedema was observed in 36%, 69%, and 92% of the BMO grades, respectively. The correlations between unilateral radiculopathy and ipsilateral facet BMO grades were 79%, 83%, and 73% (chi-square, p<0.001), respectively. Furthermore, neuroforaminal narrowing on the corresponding level was found in 35%, 38%, and 11% of cases, respectively. At follow-up imaging, facet oedema was most likely to remain unchanged or to decrease. Conclusion: The prevalence of cervical facet oedema is 9%. Cervical facet oedema is associated with ipsilateral radiculopathy. Neuroforaminal narrowing, however, is not associated with facet oedema. - Highlights: • Association between the cervical facet oedema and cervical radiculopathy was studied. • Prevalence of the cervical facet oedema was 9%. • Facet oedema was associated with radiculopathy regardless of the degree of oedema. • Neuroforaminal

Eight Key Facets of Small Business Management.

Science.gov (United States)

Scott, James Calvert

1980-01-01

Identifies eight key facets of small business management and suggests activities that may be used to assist in their development. The key facets are (1) product or service, (2) competition, (3) marketing strategies, (4) personnel needs, (5) equipment and facility needs, (6) finances, (7) planning, and (8) entrepreneurship. (JOW)

Future ATM Concepts Evaluation Tool (FACET) Interface Control Document

Science.gov (United States)

Grabbe, Shon R.

2017-01-01

This Interface Control Document (ICD) documents the airspace adaptation and air traffic inputs of NASA's Future ATM Concepts and Evaluation Tool (FACET). Its intended audience is the project manager, project team, development team, and stakeholders interested in interfacing with the system. FACET equips Air Traffic Management (ATM) researchers and service providers with a way to explore, develop and evaluate advanced air transportation concepts before they are field-tested and eventually deployed. FACET is a flexible software tool that is capable of quickly generating and analyzing thousands of aircraft trajectories. It provides researchers with a simulation environment for preliminary testing of advanced ATM concepts. Using aircraft performance profiles, airspace models, weather data, and flight schedules, the tool models trajectories for the climb, cruise, and descent phases of flight for each type of aircraft. An advanced graphical interface displays traffic patterns in two and three dimensions, under various current and projected conditions for specific airspace regions or over the entire continental United States. The system is able to simulate a full day's dynamic national airspace system (NAS) operations, model system uncertainty, measure the impact of different decision-makers in the NAS, and provide analysis of the results in graphical form, including sector, airport, fix, and airway usage statistics. NASA researchers test and analyze the system-wide impact of new traffic flow management algorithms under anticipated air traffic growth projections on the nation's air traffic system. In addition to modeling the airspace system for NASA research, FACET has also successfully transitioned into a valuable tool for operational use. Federal Aviation Administration (FAA) traffic flow managers and commercial airline dispatchers have used FACET technology for real-time operations planning. FACET integrates live air traffic data from FAA radar systems and weather data

Independent effects of step length and foot strike pattern on tibiofemoral joint forces during running.

Science.gov (United States)

Bowersock, Collin D; Willy, Richard W; DeVita, Paul; Willson, John D

2017-10-01

The purpose of this study was to examine the effects of step length and foot strike pattern along with their interaction on tibiofemoral joint (TFJ) and medial compartment TFJ kinetics during running. Nineteen participants ran with a rear foot strike pattern at their preferred speed using a short (-10%), preferred, and long (+10%) step length. These step length conditions were then repeated using a forefoot strike pattern. Regardless of foot strike pattern, a 10% shorter step length resulted in decreased peak contact force, force impulse per step, force impulse per kilometre, and average loading rate at the TFJ and medial compartment, while a 10% increased step length had the opposite effects (all P forefoot strike pattern significantly lowered TFJ and medial compartment TFJ average loading rates compared with a rear foot strike pattern (both forefoot strike pattern produced the greatest reduction in peak medial compartment contact force (P < 0.05). Knowledge of these running modification effects may be relevant to the management or prevention of TFJ injury or pathology among runners.

Lumbar facet anatomy changes in spondylolysis: a comparative skeletal study

Science.gov (United States)

Dar, Gali; Peleg, Smadar; Steinberg, Nili; Alperovitch-Najenson, Dvora; Salame, Khalil; Hershkovitz, Israel

2007-01-01

Opinions differ as to the exact mechanism responsible for spondylolysis (SP) and whether individuals with specific morphological characteristics of the lumbar vertebral neural arch are predisposed to SP. The aim of our study was to reveal the association between SP and the architecture of lumbar articular facets and the inter-facet region. Methods: Using a Microscribe three-dimensional apparatus (Immersion Co., San Jose, CA, USA), length, width and depth of all articular facets and all inter-facet distances in the lumbar spine (L1–L5) were measured. From the Hamann-Todd Human Osteological Collection (Cleveland Museum of Natural History, OH, USA) 120 normal male skeletons with lumbar spines in the control group and 115 with bilateral SP at L5 were selected. Analysis of variance was employed to examine the differences between spondylolytic and normal spines. Results: Three profound differences between SP and the norm appeared: (1) in individuals with SP, the size and shape of L4’s neural arch had significantly greater inter-facet widths, significantly shorter inter-facet heights and significantly shorter and narrower articular facets; (2) only in the L4 vertebra in individuals with SP was the inferior inter-facet width greater in size than the superior inter-facet width of the vertebra below (L5) (38.7 mm versus 40 mm); (3) in all lumbar vertebrae, the right inferior articular facets in individuals with SP were flatter compared to the control group. Conclusions: Individuals with L4 “SP” characteristics are at a greater risk of developing fatigue fractures in the form of spondylolysis at L5. PMID:17440753

Relationship between Joint Position Sense, Force Sense, and Muscle Strength and the Impact of Gymnastic Training on Proprioception

Directory of Open Access Journals (Sweden)

Bartłomiej Niespodziński

2018-01-01

Full Text Available The aims of this study were (1 to assess the relationship between joint position (JPS and force sense (FS and muscle strength (MS and (2 to evaluate the impact of long-term gymnastic training on particular proprioception aspects and their correlations. 17 elite adult gymnasts and 24 untrained, matched controls performed an active reproduction (AR and passive reproduction (PR task and a force reproduction (FR task at the elbow joint. Intergroup differences and the relationship between JPS, FS, and MS were evaluated. While there was no difference in AR or PR between groups, absolute error in the control group was higher during the PR task (7.15 ± 2.72° than during the AR task (3.1 ± 1.93°. Mean relative error in the control group was 61% higher in the elbow extensors than in the elbow flexors during 50% FR, while the gymnast group had similar results in both reciprocal muscles. There was no linear correlation between JPS and FS in either group; however, FR was negatively correlated with antagonist MS. In conclusion, this study found no evidence for a relationship between the accuracy of FS and JPS at the elbow joint. Long-term gymnastic training improves the JPS and FS of the elbow extensors.

Abnormal growth of faceted (WC) grains in a (Co) liquid matrix

International Nuclear Information System (INIS)

Park, Y.J.; Yoon, D.Y.

1996-01-01

If the grains dispersed in a liquid matrix are spherical, their surface atomic structure is expected to be rough (diffuse), and their coarsening has been observed to be controlled by diffusion in the matrix. They do not, furthermore, undergo abnormal growth. On the other hand, in some compound material systems, the grains in liquid matrices are faceted and often show abnormal coarsening behavior. Their faceted surface planes are expected to be singular (atomically flat) and therefore grow by a defect-assisted process and two-dimensional (2-D) nucleation. Contrary to the usual coarsening theories, their growth velocity is not linearly dependent on the driving force arising from the grain size difference. If the growth of the faceted grains occurs by 2-D nucleation, the rate is expected to increase abruptly at a critical supersaturation, as has been observed in crystal growth in melts and solutions. It is proposed that this growth mechanism leads to the abnormal grain coarsening. The 2-D nucleation theory predicts that there is a threshold initial grain size for the abnormal grain growth (AGG), and the propensity for AGG will increase with the heat-treatment temperature. The AGG behavior will also vary with the defects in the grains. These predictions are qualitatively confirmed in the sintered WC-Co alloy prepared from fine (0.85-microm) and coarse (5.48-microm) WC powders and their mixtures. The observed dependence of the AGG behavior on the sintering temperature and the milling of the WC powder is also qualitatively consistent with the predicted behavior

Acromioclavicular joint separation

Directory of Open Access Journals (Sweden)

Devan Pandya, BS

2018-04-01

Full Text Available History of present illness: A 30-year-old male was brought in by ambulance to the emergency department as a trauma activation after a motorcycle accident. The patient was the helmeted rider of a motorcycle traveling at an unknown speed when he lost control and was thrown off his vehicle. He denied loss of consciousness, nausea, or vomiting. The patient’s vital signs were stable and his only complaint was pain around his left shoulder. On exam, the patient had a prominent left clavicle without skin compromise. He had adequate range of motion in the left shoulder with moderate pain, and his left upper extremity was neurovascularly intact. Significant findings: Plain films of the left shoulder showed elevation of the left clavicle above the acromion. There was an increase in the acromioclavicular (AC and coracoclavicular (CC distances (increased joint distances marked with red and blue arrows, respectively. A normal AC joint measures 1-3 mm whereas a normal CC distance measures 11-13 mm.1 The injury was classified as a Rockwood type III AC joint separation. Discussion: The AC joint is a synovial joint between an oval facet on the acromion and a similar facet on the distal end of the clavicle. Horizontal stability is provided by the AC joint while axial stability is provided by the CC joint.2,3 AC joint injuries account for about 9%-12% of shoulder girdle injuries, and the most common mechanism is direct trauma.4,5 Initial evaluation with imaging includes plain films with three views: the anterior-posterior (AP view with the shoulder in internal and external rotation as well as an axillary, or scapula-Y view (sensitivity 40%, specificity 90% for all films.6,7 AC joint injuries are classified by the Rockwood system.8 Type I involves a sprain or incomplete tear of the AC ligaments with an intact CC ligament. The AC joint appears normal on X-ray, but can become widened with stress, achieved by having the patient hold a 10-15 pound weight from each

Joint made of shape memory alloy

International Nuclear Information System (INIS)

Amano, Kazuo; Enomoto, Kunio

1998-01-01

The present invention provides a joint which is less loosen even if it is used under a circumference undergoing heat cycles such as in a nuclear power plant. Namely, a liner shape has a structure different between the right-to-left, which is different from existent right and left symmetrical shape. A groove is formed on the side of pipeline to be connected, and upon joint connection, the liner is pushed into the groove formed on the pipeline to connect them by the force caused upon transformation of the shape memory alloy. In the joint having such a structure, the clamping force of the joint is less reduced by the effects of heat cycles. Even when the clamping force is reduced by some or other causes, the joint is not dropped off from the pipeline. Even when the joint made of a shape memory alloy of a type using a liner is used as a joint for connecting longitudinal pipelines of a nuclear power plant, the reliability and the safety can be maintained. (I.S.)

Does Service Interdependence Take Jointness Too Far?

National Research Council Canada - National Science Library

Downs, Christopher G

2008-01-01

... integration to support and improve the warfighting effectiveness of joint force commanders. The ability to effectively employ joint forces has increased the lethality, agility, and operational precision of the United States military...

Pharmacy faculty workplace issues: findings from the 2009-2010 COD-COF Joint Task Force on Faculty Workforce.

Science.gov (United States)

Desselle, Shane P; Peirce, Gretchen L; Crabtree, Brian L; Acosta, Daniel; Early, Johnnie L; Kishi, Donald T; Nobles-Knight, Dolores; Webster, Andrew A

2011-05-10

Many factors contribute to the vitality of an individual faculty member, a department, and an entire academic organization. Some of the relationships among these factors are well understood, but many questions remain unanswered. The Joint Task Force on Faculty Workforce examined the literature on faculty workforce issues, including the work of previous task forces charged by the American Association of Colleges of Pharmacy (AACP). We identified and focused on 4 unique but interrelated concepts: organizational culture/climate, role of the department chair, faculty recruitment and retention, and mentoring. Among all 4 resides the need to consider issues of intergenerational, intercultural, and gender dynamics. This paper reports the findings of the task force and proffers specific recommendations to AACP and to colleges and schools of pharmacy.

The Association of Academic Health Sciences Libraries' legislative activities and the Joint Medical Library Association/Association of Academic Health Sciences Libraries Legislative Task Force.

Science.gov (United States)

Zenan, Joan S

2003-04-01

The Association of Academic Health Sciences Libraries' (AAHSL's) involvement in national legislative activities and other advocacy initiatives has evolved and matured over the last twenty-five years. Some activities conducted by the Medical Library Association's (MLA's) Legislative Committee from 1976 to 1984 are highlighted to show the evolution of MLA's and AAHSL's interests in collaborating on national legislative issues, which resulted in an agreement to form a joint legislative task force. The history, work, challenges, and accomplishments of the Joint MLA/AAHSL Legislative Task Force, formed in 1985, are discussed.

Cervical facet dislocation adjacent to the fused motion segment

Directory of Open Access Journals (Sweden)

Kunio Yokoyama

2016-01-01

Full Text Available This study reports on a case that forces re-examination of merits and demerits of anterior cervical fusion. A 79-year-old male was brought to the emergency room (ER of our hospital after he fell and struck the occipital region of his head following excessive alcohol consumption. Four years prior, he had undergone anterior cervical discectomy and fusion of C5/6 and a magnetic resonance imaging (MRI performed 3 years after this surgery indicated that he was suffering from degeneration of C6/7 intervertebral discs. After arriving at the ER, he presented motor impairment at level C7 and lower of manual muscle testing grade 1 as well as moderate loss of physical sensation from the trunk and peripheries of both upper limbs to the peripheries of both lower limbs (Frankel B. Cervical computed tomography (CT indicated anterior dislocation of C6/7, and MRI indicated severe spinal cord edema. We performed manipulative reduction of C6/7 with the patient under general anesthesia. Next, we performed laminectomy on C5-T1 and posterior fusion on C6/7. Postoperative CT indicated that cervical alignment had improved, and MRI indicated that the spinal cord edema observed prior to surgery had been mitigated. Three months after surgery, motor function and sensory impairment of the lower limbs had improved, and the patient was ambulatory upon discharge from the hospital (Frankel D. In the present case, although C5 and 6 were rigidly fused, degeneration of the C6/7 intervertebral disc occurred and stability was compromised. As a result, even slight trauma placed a severe dynamic burden on the facet joint of C6/7, which led to dislocation.

Subtalar joint stress imaging with tomosynthesis.

Science.gov (United States)

Teramoto, Atsushi; Watanabe, Kota; Takashima, Hiroyuki; Yamashita, Toshihiko

2014-06-01

The purpose of this study was to perform stress imaging of hindfoot inversion and eversion using tomosynthesis and to assess the subtalar joint range of motion (ROM) of healthy subjects. The subjects were 15 healthy volunteers with a mean age of 29.1 years. Coronal tomosynthesis stress imaging of the subtalar joint was performed in a total of 30 left and right ankles. A Telos stress device was used for the stress load, and the load was 150 N for both inversion and eversion. Tomographic images in which the posterior talocalcaneal joint could be confirmed on the neutral position images were used in measurements. The angle of the intersection formed by a line through the lateral articular facet of the posterior talocalcaneal joint and a line through the surface of the trochlea of the talus was measured. The mean change in the angle of the calcaneus with respect to the talus was 10.3 ± 4.8° with inversion stress and 5.0 ± 3.8° with eversion stress from the neutral position. The result was a clearer depiction of the subtalar joint, and inversion and eversion ROM of the subtalar joint was shown to be about 15° in healthy subjects. Diagnostic, Level IV.

Joint Force Quarterly. Number 34, Spring 2003

Science.gov (United States)

2003-07-01

Office of the Chairman LTG George W. Casey, Jr., USA ■ The Joint Staff MG Reginal G. Clemmons , USA ■ National War College A. Denis Clift ■ Joint...vol. 138, no. 91 (June 23, 1992), p. S 8602. 2 Maurice Matloff, editor, American Military History (Washington: Government Printing Office, 1969), p...was basically flawed and historically inac- curate. During the late 1930s General Maurice Gamelin exacerbated a faulty doctrine by shut- ting off all

Objective Assessment of Joint Stiffness: A Clinically Oriented Hardware and Software Device with an Application to the Shoulder Joint

OpenAIRE

McQuade, Kevin; Price, Robert; Liu, Nelson; Ciol, Marcia A

2012-01-01

Examination of articular joints is largely based on subjective assessment of the “end-feel” of the joint in response to manually applied forces at different joint orientations. This technical report aims to describe the development of an objective method to examine joints in general, with specific application to the shoulder, and suitable for clinical use. We adapted existing hardware and developed laptop-based software to objectively record the force/displacement behavior of the glenohumeral...

A Patient-Specific Foot Model for the Estimate of Ankle Joint Forces in Patients with Juvenile Idiopathic Arthritis.

Science.gov (United States)

Prinold, Joe A I; Mazzà, Claudia; Di Marco, Roberto; Hannah, Iain; Malattia, Clara; Magni-Manzoni, Silvia; Petrarca, Maurizio; Ronchetti, Anna B; Tanturri de Horatio, Laura; van Dijkhuizen, E H Pieter; Wesarg, Stefan; Viceconti, Marco

2016-01-01

Juvenile idiopathic arthritis (JIA) is the leading cause of childhood disability from a musculoskeletal disorder. It generally affects large joints such as the knee and the ankle, often causing structural damage. Different factors contribute to the damage onset, including altered joint loading and other mechanical factors, associated with pain and inflammation. The prediction of patients' joint loading can hence be a valuable tool in understanding the disease mechanisms involved in structural damage progression. A number of lower-limb musculoskeletal models have been proposed to analyse the hip and knee joints, but juvenile models of the foot are still lacking. This paper presents a modelling pipeline that allows the creation of juvenile patient-specific models starting from lower limb kinematics and foot and ankle MRI data. This pipeline has been applied to data from three children with JIA and the importance of patient-specific parameters and modelling assumptions has been tested in a sensitivity analysis focused on the variation of the joint reaction forces. This analysis highlighted the criticality of patient-specific definition of the ankle joint axes and location of the Achilles tendon insertions. Patient-specific detection of the Tibialis Anterior, Tibialis Posterior, and Peroneus Longus origins and insertions were also shown to be important.

Effect of Calcaneus Fracture Gap Without Step-Off on Stress Distribution Across the Subtalar Joint.

Science.gov (United States)

Barrick, Brett; Joyce, Donald A; Werner, Frederick W; Iannolo, Maria

2017-03-01

Subtalar arthritis is a common consequence following calcaneal fracture, and its development is related to the severity of the fracture. Previous calcaneal fracture models have demonstrated altered contact characteristics when a step-off is created in the posterior facet articular surface. Changes in posterior facet contact characteristics have not been previously characterized for calcaneal fracture gap without step-off. The contact characteristics (peak pressure, area of contact, and centroid of pressure) of the posterior facet of the subtalar joint were determined in 6 cadaveric specimens. After creating a calcaneal fracture to simulate a Sanders type II fracture, the contact characteristics were determined with the posterior facet anatomically reduced followed by an incremental increase in fracture gap displacement of 2, 3, and 5 mm without a step-off of the articular surface. Peak pressure on the medial fragment was significantly less with a 5-mm gap compared to a 2- or 3-mm gap, or reduced. On the lateral fragment, the peak pressure was significantly increased with a 5-mm gap compared to a 2- or 3-mm gap. Contact area significantly changed with increased gap. In this study, there were no significant differences in contact characteristics between a <3-mm gap and an anatomically reduced fracture, conceding the study limitations including limiting axial loading to 50% of donor body weight. A small amount of articular incongruity without a step-off can be tolerated by the subtalar joint, in contrast to articular incongruity with a step-off present.

Metallic joints for very high vacuum; Joints metalliques pour ultra-vide

Energy Technology Data Exchange (ETDEWEB)

Paigne, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1961-07-01

After defining three main types of joint; three types of distribution of the tightening force in the clamps are demonstrated; the distribution of stresses, distortion and displacements in these clamps is then calculated by means of the theory of elasticity. This is followed by experimental results on a particular means of tightening (i.e. screw-clamps). From a brief discussion on the behaviour of the clamps it is possible finally to define other types of joint deriving from the main types originally foreseen. (author) [French] Apres avoir defini trois principaux types de joints, on met en evidence trois types de distribution des forces de serrage des brides; puis on calcule a l'aide de la theorie de l'elasticite la distribution des contraintes, deformations et deplacements dans ces brides. On donne ensuite des resultats experimentaux sur un mode de serrage particulier (cas des serres-joints). Une discussion sommaire sur le comportement des brides permet de definir finalement d'autres types de joints derivant des types principaux envisages initialement. (auteur)

Large conservation gains possible for global biodiversity facets

Science.gov (United States)

Pollock, Laura J.; Thuiller, Wilfried; Jetz, Walter

2017-06-01

Different facets of biodiversity other than species numbers are increasingly appreciated as critical for maintaining the function of ecosystems and their services to humans. While new international policy and assessment processes such as the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) recognize the importance of an increasingly global, quantitative and comprehensive approach to biodiversity protection, most insights are still focused on a single facet of biodiversity—species. Here we broaden the focus and provide an evaluation of how much of the world’s species, functional and phylogenetic diversity of birds and mammals is currently protected and the scope for improvement. We show that the large existing gaps in the coverage for each facet of diversity could be remedied by a slight expansion of protected areas: an additional 5% of the land has the potential to more than triple the protected range of species or phylogenetic or functional units. Further, the same areas are often priorities for multiple diversity facets and for both taxa. However, we find that the choice of conservation strategy has a fundamental effect on outcomes. It is more difficult (that is, requires more land) to maximize basic representation of the global biodiversity pool than to maximize local diversity. Overall, species and phylogenetic priorities are more similar to each other than they are to functional priorities, and priorities for the different bird biodiversity facets are more similar than those of mammals. Our work shows that large gains in biodiversity protection are possible, while also highlighting the need to explicitly link desired conservation objectives and biodiversity metrics. We provide a framework and quantitative tools to advance these goals for multi-faceted biodiversity conservation.

Large conservation gains possible for global biodiversity facets.

Science.gov (United States)

Pollock, Laura J; Thuiller, Wilfried; Jetz, Walter

2017-06-01

Different facets of biodiversity other than species numbers are increasingly appreciated as critical for maintaining the function of ecosystems and their services to humans. While new international policy and assessment processes such as the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) recognize the importance of an increasingly global, quantitative and comprehensive approach to biodiversity protection, most insights are still focused on a single facet of biodiversity-species. Here we broaden the focus and provide an evaluation of how much of the world's species, functional and phylogenetic diversity of birds and mammals is currently protected and the scope for improvement. We show that the large existing gaps in the coverage for each facet of diversity could be remedied by a slight expansion of protected areas: an additional 5% of the land has the potential to more than triple the protected range of species or phylogenetic or functional units. Further, the same areas are often priorities for multiple diversity facets and for both taxa. However, we find that the choice of conservation strategy has a fundamental effect on outcomes. It is more difficult (that is, requires more land) to maximize basic representation of the global biodiversity pool than to maximize local diversity. Overall, species and phylogenetic priorities are more similar to each other than they are to functional priorities, and priorities for the different bird biodiversity facets are more similar than those of mammals. Our work shows that large gains in biodiversity protection are possible, while also highlighting the need to explicitly link desired conservation objectives and biodiversity metrics. We provide a framework and quantitative tools to advance these goals for multi-faceted biodiversity conservation.

Impact of Project Leadership Facets on Project Outcome

Directory of Open Access Journals (Sweden)

Arslan Ayub

2015-08-01

Full Text Available The study analyzes the role of project leadership facets on effective project outcome. Numerous such initiatives have already been taken on project outcome/performance in the context of apposite leadership styles or project management. However, the current study is unique in the milieu of project outcome that it introduces a new leadership approach, which throws light on the significance of variant leadership facets on project outcome. The study uses explanatory approach; primary data is collected from project management professionals working in different project organizations. The study uses structural equation model (SEM technique to test the hypothesis. The study found a positive relationship between project leadership facets and project outcome.

Crack Front Segmentation and Facet Coarsening in Mixed-Mode Fracture

Science.gov (United States)

Chen, Chih-Hung; Cambonie, Tristan; Lazarus, Veronique; Nicoli, Matteo; Pons, Antonio J.; Karma, Alain

2015-12-01

A planar crack generically segments into an array of "daughter cracks" shaped as tilted facets when loaded with both a tensile stress normal to the crack plane (mode I) and a shear stress parallel to the crack front (mode III). We investigate facet propagation and coarsening using in situ microscopy observations of fracture surfaces at different stages of quasistatic mixed-mode crack propagation and phase-field simulations. The results demonstrate that the bifurcation from propagating a planar to segmented crack front is strongly subcritical, reconciling previous theoretical predictions of linear stability analysis with experimental observations. They further show that facet coarsening is a self-similar process driven by a spatial period-doubling instability of facet arrays.

Domains and facets: hierarchical personality assessment using the revised NEO personality inventory.

Science.gov (United States)

Costa, P T; McCrae, R R

1995-02-01

Personality traits are organized hierarchically, with narrow, specific traits combining to define broad, global factors. The Revised NEO Personality Inventory (NEO-PI-R; Costa & McCrae, 1992c) assesses personality at both levels, with six specific facet scales in each of five broad domains. This article describes conceptual issues in specifying facets of a domain and reports evidence on the validity of NEO-PI-R facet scales. Facet analysis-the interpretation of a scale in terms of the specific facets with which it correlates-is illustrated using alternative measures of the five-factor model and occupational scales. Finally, the hierarchical interpretation of personality profiles is discussed. Interpretation on the domain level yields a rapid understanding of the individual interpretation of specific facet scales gives a more detailed assessment.

Tests of beam-based alignement at FACET

CERN Document Server

Latina, A; Schulte, D; Adli, E

2014-01-01

The performance of future linear colliders will depend critically on beam-based alignment (BBA) and feedback systems, which will play a crucial role in guaranteeing the low emittance transport throughout such machines. BBA algorithms designed to improve the beam transmission in a linac by simultaneously optimising the trajectory and minimising the residual dispersion, have thoughtfully been studied in theory over the last years, and successfully verified experimentally. One such technique is called Dispersion-Free Steering (DFS). A careful study of the DFS performance at the SLAC test facility FACET lead us to design a beam-based technique specifically targeted to reduce the impact of transverse short-range wakefields, rather than of the dispersion, being the wakefields the limiting factor to the FACET performance. This technique is called Wakefield-Free Steering (WFS). The results of the first tests of WFS at FACET are presented in this paper.

Improving personality facet scores with multidimensional computer adaptive testing

DEFF Research Database (Denmark)

Makransky, Guido; Mortensen, Erik Lykke; Glas, Cees A W

2013-01-01

personality tests contain many highly correlated facets. This article investigates the possibility of increasing the precision of the NEO PI-R facet scores by scoring items with multidimensional item response theory and by efficiently administering and scoring items with multidimensional computer adaptive...

AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training

Science.gov (United States)

Allison, Jerry D.; Clements, Jessica B.; Coffey, Charles W.; Fahey, Frederic H.; Gress, Dustin A.; Kinahan, Paul E.; Nickoloff, Edward L.; Mawlawi, Osama R.; MacDougall, Robert D.; Pizzuitello, Robert J.

2015-01-01

The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics Training. The mission of this task force was to assemble a representative group of stakeholders to: Estimate the demand for board‐certified nuclear medicine physicists in the next 5–10 years,Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, andIdentify approaches that may be considered to facilitate the training of nuclear medicine physicists. As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face‐to‐face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission. PACS number: 01.40.G‐ PMID:26699325

Electrical anisotropy properties of ZnO nanorods analyzed by conductive atomic force microscopy

International Nuclear Information System (INIS)

Wu Yunfeng; Yu Naisen; Liu Dongping; He Yangyang; Liu Yuanda; Liang Hongwei; Du Guotong

2013-01-01

Highlights: ► The electrical properties of one individual lying ZnO nanorod were performed by C-AFM measurement. ► Inhomogeneous spatial current distribution was detected. ► Current was detected along the side facets while no current was detected in the top plane for ZnO nanorod. ► The side facets were more conductive than the top facets of ZnO nanorods. - Abstract: In this study, we have prepared ZnO nanorods on cracked GaN substrates using aqueous solution method. Unique electrical characterization of one individual lying ZnO nanorod is analyzed by conductive atomic force microscopy (C-AFM). Effect of anisotropy properties on the conductivity of a single nanorod has been investigated. The current maps of ZnO nanorods have been simultaneously recorded with the topography which is gained by AFM-contact mode. The C-AFM measurement present local current–voltage (I–V) characteristics of the side facets of one individual lying nanorod, however, no current is detected on the top facets of ZnO nanorods. Measurement results indicate that the side facets are more electrically active than the top facets of ZnO nanorods due to lower Schottky barrier height of the side facets.

Joint contact loading in forefoot and rearfoot strike patterns during running.

Science.gov (United States)

Rooney, Brandon D; Derrick, Timothy R

2013-09-03

Research concerning forefoot strike pattern (FFS) versus rearfoot strike pattern (RFS) running has focused on the ground reaction force even though internal joint contact forces are a more direct measure of the loads responsible for injury. The main purpose of this study was to determine the internal loading of the joints for each strike pattern. A secondary purpose was to determine if converted FFS and RFS runners can adequately represent habitual runners with regards to the internal joint loading. Using inverse dynamics to calculate the net joint moments and reaction forces and optimization techniques to estimate muscle forces, we determined the axial compressive loading at the ankle, knee, and hip. Subjects consisted of 15 habitual FFS and 15 habitual RFS competitive runners. Each subject ran at a preferred running velocity with their habitual strike pattern and then converted to the opposite strike pattern. Plantar flexor muscle forces and net ankle joint moments were greater in the FFS running compared to the RFS running during the first half of the stance phase. The average contact forces during this period increased by 41.7% at the ankle and 14.4% at the knee joint during FFS running. Peak ankle joint contact force was 1.5 body weights greater during FFS running (pstrike pattern. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solder joint technology materials, properties, and reliability

CERN Document Server

Tu, King-Ning

2007-01-01

Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

Force Protection and Command Relationships: Who's Responsible

National Research Council Canada - National Science Library

Moller, James

1998-01-01

.... This monograph analyzes the joint force protection program by investigating the terms: command, chain of command, command relationship, and how these terms authorize and empower a commander to implement this program across the joint force...

Fighting Fires with Fire - An Airman's Perspective on the Development of Joint Publication 3-09, Doctrine for Joint Fire Support

National Research Council Canada - National Science Library

Vittori, Jay

1999-01-01

This study is an Air Force doctrinaire's account of the development of Joint Publication 3-09, Doctrine for Joint Fire Support, the most controversial joint military doctrine publication ever produced...

The Structure of Spatial Ability Items: A Faceted Analysis.

Science.gov (United States)

Guttman, Ruth; Shoham, Ilana

1982-01-01

Eight spatial tests assembled with a mapping sentence of four content facets (rule type, dimensionality, presence or absence of rotation, and test format) were administered to 800 individuals. Smallest Space Analysis of an intercorrelation matrix yielded three facets which formed distinct regions in a two-dimensional projection of a…

Faceted MoS2 nanotubes and nanoflowers

International Nuclear Information System (INIS)

Deepak, Francis Leonard; Mayoral, Alvaro; Yacaman, Miguel Jose

2009-01-01

A simple synthesis of novel faceted MoS 2 nanotubes (NTs) and nanoflowers (NFs) starting from molybdenum oxide and thiourea as the sulphur source is reported. The MoS 2 nanotubes with the faceted morphology have not been observed before. Further the as-synthesized MoS 2 nanotubes have high internal surface area. The nanostructures have been characterized by a variety of electron microscopy techniques. It is expected that these MoS 2 nanostrutures will find important applications in energy storage, catalysis and field emission.

Long-Term Developmental Changes in Children's Lower-Order Big Five Personality Facets.

Science.gov (United States)

de Haan, Amaranta; De Pauw, Sarah; van den Akker, Alithe; Deković, Maja; Prinzie, Peter

2017-10-01

This study examined long-term developmental changes in mother-rated lower-order facets of children's Big Five dimensions. Two independent community samples covering early childhood (2-4.5 years; N = 365, 39% girls) and middle childhood to the end of middle adolescence (6-17 years; N = 579, 50% girls) were used. All children had the Belgian nationality. Developmental changes were examined using cohort-sequential latent growth modeling on the 18 facets of the Hierarchical Personality Inventory for Children. In early childhood, changes were mostly similar across child gender. Between 2 and 4.5 years, several facets showed mean-level stability; others changed in the direction of less Extraversion and Emotional Stability, and more Benevolence and Imagination. The lower-order facets of Conscientiousness showed opposite changes. Gender differences became more apparent from middle childhood onward for facets of all dimensions except Imagination, for which no gender differences were found. Between 6 and 17 years, same-dimension facets showed different shapes of growth. Facets that changed linearly changed mostly in the direction of less Extraversion, Benevolence, Conscientiousness, Emotional Stability, and Imagination. Changes in facets for which nonlinear growth was found generally moved in direction or magnitude during developmental transitions. This study provides comprehensive, fine-grained knowledge about personality development during the first two decades of life. © 2016 Wiley Periodicals, Inc.

Air Force Graduate and Undergraduate Educational Programs: Need, Structure and Focus

National Research Council Canada - National Science Library

Alley, Tony

1995-01-01

.... It also examined the broad facets of off duty, voluntary education program to include value to the Air Force and individual, cost versus return on investment, and the impact on career progression...

Specific oriented metal-organic framework membranes and their facet-tuned separation performance.

Science.gov (United States)

Mao, Yiyin; Su, Binbin; Cao, Wei; Li, Junwei; Ying, Yulong; Ying, Wen; Hou, Yajun; Sun, Luwei; Peng, Xinsheng

2014-09-24

Modulating the crystal morphology, or the exposed crystal facets, of metal-organic frameworks (MOFs) expands their potential applications in catalysis, adsorption, and separation. In this article, by immobilizing the citrate modulators on Au nanoparticles and subsequently being fixed on solid copper hydroxide nanostrands, a well-intergrown and oriented HKUST-1 cube crystal membrane was formed at room temperature. In contrast, in the absence of Au nanoparticles, well-intergrown and oriented cuboctahedron and octahedron membranes were formed in water/ethanol and ethanol, respectively. The gas separation performances of these HKUST-1 membranes were tuned via their exposed facets with defined pore sizes. The HKUST-1 cube membrane with exposed {001} facets demonstrated the highest permeance but lowest gas binary separation factors, while the octahedron membrane with exposed {111} facets presented the highest separation factors but lowest permeance, since the window size of {111} facets is 0.46 nm which is smaller than 0.9 nm of {001} facets. Separation of 0.38 nm CO2 from 0.55 nm SF6 was realized by the HKUST-1 octahedron membrane. As a proof of concept, this will open a new way to design MOF-related separation membranes by facet controlling.

Image-based multiscale mechanical modeling shows the importance of structural heterogeneity in the human lumbar facet capsular ligament.

Science.gov (United States)

Zarei, Vahhab; Liu, Chao J; Claeson, Amy A; Akkin, Taner; Barocas, Victor H

2017-08-01

The lumbar facet capsular ligament (FCL) primarily consists of aligned type I collagen fibers that are mainly oriented across the joint. The aim of this study was to characterize and incorporate in-plane local fiber structure into a multiscale finite element model to predict the mechanical response of the FCL during in vitro mechanical tests, accounting for the heterogeneity in different scales. Characterization was accomplished by using entire-domain polarization-sensitive optical coherence tomography to measure the fiber structure of cadaveric lumbar FCLs ([Formula: see text]). Our imaging results showed that fibers in the lumbar FCL have a highly heterogeneous distribution and are neither isotropic nor completely aligned. The averaged fiber orientation was [Formula: see text] ([Formula: see text] in the inferior region and [Formula: see text] in the middle and superior regions), with respect to lateral-medial direction (superior-medial to inferior-lateral). These imaging data were used to construct heterogeneous structural models, which were then used to predict experimental gross force-strain behavior and the strain distribution during equibiaxial and strip biaxial tests. For equibiaxial loading, the structural model fit the experimental data well but underestimated the lateral-medial forces by [Formula: see text]16% on average. We also observed pronounced heterogeneity in the strain field, with stretch ratios for different elements along the lateral-medial axis of sample typically ranging from about 0.95 to 1.25 during a 12% strip biaxial stretch in the lateral-medial direction. This work highlights the multiscale structural and mechanical heterogeneity of the lumbar FCL, which is significant both in terms of injury prediction and microstructural constituents' (e.g., neurons) behavior.

Experimental joint immobilization in guinea pigs. Effects on the knee joint

Science.gov (United States)

Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

1980-01-01

In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

The prevalence cervical facet arthrosis: an osseous study in a cadveric population.

Science.gov (United States)

Lee, Michael J; Riew, K Daniel

2009-09-01

Cervical facet arthrosis has been implicated as a cause for neck pain, radiculopathy, occipital headache, and ear pain. The objective of this study was to examine the occurrence of facet arthrosis in the cervical spine. This study examined cadaveric specimens from the Hamann Todd Collection. None. None. Four hundred sixty-five skeletally mature human cervical spines from the Hamann Todd Collection in the Cleveland Museum of Natural History were obtained for analysis. We analyzed the facets for arthrosis. We graded no arthrosis as Grade 0. Facets with peripheral osteophytic reaction, but with no lateral mass distortion were graded as Grade 1. Facets with peripheral osteophytic reaction and lateral mass distortion were graded as Grade 2. Facets that were ankylosed were graded as Grade 3. Each specimen was examined bilaterally at levels from C2-C3 through C6-C7, yielding 4,650 specimen assessments. The data were analyzed to compare cervical levels, gender, facet side, age groups, and race. Proportion analysis, using the Fisher exact test, was used to assess for statistical difference between various groupings. In the entire population of 465 specimens, the upper cervical specimens appeared to be affected by facet arthrosis more frequently than the lower levels; 12.37% of the specimens had bony evidence of arthrosis at the C2-C3 level; 13.33% of the specimens had arthrosis occur at the C3-C4 level; 14.62% at the C4-C5 level; 7.85% at the C5-C6 level, and 4.84% at the C6-C7 level. The large majority of all cervical facet arthrosis was found to be Grade 1 at all levels. In the older population, the prevalence of facet arthrosis is as high as 29.87% for the C4-C5 level. C4-C5 level appears to be affected the most frequently, followed by the C3-C4 level, then C2-C3, C5-C6, and C6-C7. The prevalence of cervical facet arthrosis increases with age, and occurs more commonly in the upper cervical spine.

The usability issues of faceted navigation in digital libraries

Directory of Open Access Journals (Sweden)

Eliane Blumer

2014-05-01

For more than five years, the project ACCEPT, a subproject of a Swiss national project called e-lib.ch, analyzes the usability and usefulness of digital libraries, by using user oriented methods. Experience has shown that filters provided through faceted navigation are considered as positive and very useful by end users. Nevertheless, based on different test results, several returning mistakes have been detected and it turns out that there are some ‘unwritten standards’ concerning e.g. position, labelling or ranking which should be respected to fulfil the aim of a good usability which users do expect of such web services. In this poster we will first give an introduction to faceted navigation, actual design issues and their use in digital libraries and then present testing methods, which can be easily applied in a digital library context. Together with a list of best practices concerning faceted navigation drawn out of different test experiences, the paper should give the reader all important information to evaluate its current faceted navigation and see where improvements could be made.

Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

Energy Technology Data Exchange (ETDEWEB)

Amann, J.; Bane, K.; /SLAC

2009-10-30

This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

International Nuclear Information System (INIS)

Amann, J.; Bane, K.

2009-01-01

This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

Technical Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

Energy Technology Data Exchange (ETDEWEB)

None, None

2016-08-26

Electrons can “surf” on waves of plasma – a hot gas of charged particles – gaining very high energies in very short distances. This approach, called plasma wakefield acceleration, has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider has been the focus of FACET, a National User Facility at SLAC. FACET used part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and their antimatter counterparts, positrons. Research into plasma wakefield acceleration was the primary motivation for constructing FACET. In April 2016, FACET operations came to an end to make way for the second phase of SLAC’s x-ray laser, the LCLS-II, which will use part of the tunnel occupied by FACET. FACET-II is a new test facility to provide the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II represents a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique.

Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off.

Science.gov (United States)

Charalambous, Laura; Irwin, Gareth; Bezodis, Ian N; Kerwin, David

2012-01-01

Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness during the first stance phase of the push-off. One elite sprinter performed 10 maximal sprint starts. An automatic motion analysis system (CODA, 200 Hz) with synchronized force plates (Kistler, 1000 Hz) collected kinematic profiles at the hip, knee, and ankle and ground reaction forces, providing input for inverse dynamics analyses. The lower-limb joints predominately extended and revealed a proximal-to-distal sequential pattern of maximal extensor angular velocity and positive power production. Pearson correlations revealed relationships (P push-off in different ways, depending on the phase of stance considered.

Extraversion and psychopathology: A facet-level analysis.

Science.gov (United States)

Watson, David; Stasik, Sara M; Ellickson-Larew, Stephanie; Stanton, Kasey

2015-05-01

The goal of this study was to explicate how the lower order facets of extraversion are related to psychopathology. We used a "bottom-up" approach in which specific extraversion scales from 3 comprehensive personality inventories were used to model these facets as latent factors. We collected both self-report and interview measures of a broad range of psychopathology from a large community sample. Replicating previous findings using a similar approach (Naragon-Gainey & Watson, 2014; Naragon-Gainey, Watson, & Markon, 2009), structural analyses yielded four factors: Positive Emotionality, Sociability, Assertiveness, and Experience Seeking. Scores on these latent dimensions were related to psychopathology in correlational analyses and in two sets of regressions (the first series used the four facets as predictors; the second included composite scores on the other Big Five domains as additional predictors). These results revealed a striking level of specificity. As predicted, Positive Emotionality displayed especially strong negative links to depressive symptoms and diagnoses. Sociability also was negatively related to psychopathology, showing particularly strong associations with indicators of social dysfunction and the negative symptoms of schizotypy (i.e., social anxiety, social aloofness, and restricted affectivity). Assertiveness generally had weak associations at the bivariate level but was negatively related to social anxiety and was positively correlated with some forms of externalizing. Finally, Experience Seeking had substantial positive associations with a broad range of indicators related to externalizing and bipolar disorder; it also displayed negative links to agoraphobia. These differential correlates demonstrate the importance of examining personality-psychopathology relations at the specific facet level. (c) 2015 APA, all rights reserved).

2016 FACET-II Science Workshop Summary Report

Energy Technology Data Exchange (ETDEWEB)

Hogan, Mark J., ed.

2017-07-19

The second in a series of FACET-II Science Workshops was held at SLAC National Accelerator Laboratory on October 17-19, 2016 [1]. The workshop drew thirty-five participants from eighteen different institutions including CERN, DESY, Ecole Polytechnique, FNAL, JAI, LBNL, LLNL, Radiabeam, Radiasoft, SLAC, Stony Brook, Strathclyde, Tech-X, Tsinghua, UC Boulder, UCLA and UT Austin. The 2015 workshop [2, 3] helped prioritize research directions for FACET-II. The 2016 workshop was focused on understanding what improvements are needed at the facility to support the next generation of experiments. All presentations are linked to the workshop website as a permanent record.

Joint Space Forces in Theater: Coordination is No Longer Sufficient

National Research Council Canada - National Science Library

Livergood, Brian K

2007-01-01

.... The explosive growth of and demand for joint space capabilities have outstripped the joint community's ability to provide unifying doctrine and a command and control structure to meet the demands...

Hydrothermal synthesis of magnetite particles with uncommon crystal facets

Directory of Open Access Journals (Sweden)

Junki Sato

2014-09-01

Full Text Available Hydrothermal synthesis of Fe3O4 (magnetite particles was carried out using organic compounds as morphology control agents to obtain magnetite crystals with uncommon facets. It was established that the morphology of Fe3O4 crystals obtained by hydrothermal treatment of an aqueous solution containing Fe2+ and organic compounds depended on the organic compound used. The shape of the Fe3O4 particles obtained when no additives were used was quasi-octahedral. In contrast, the addition of picolinic acid, citric acid or pyridine resulted in the formation of polyhedral crystals, indicating the presence of not only {1 1 1}, {1 0 0} and {1 1 0} facets but also high-index facets including at least {3 1 1} and {3 3 1}. When citric acid was used as an additive, octahedral crystals with {1 1 1} facets also appeared, and their size decreased as the amount of citric acid was increased. Thus, control of Fe3O4 particle morphology was achieved by a simple hydrothermal treatment using additives.

[The effect of verticalization of the resulting force (R) of weight bearing in the hip joint on morphologic characteristics of the medullary canal in the femoral shaft in patients with coxarthrosis].

Science.gov (United States)

Jovanović, S

1992-01-01

An influence of verticalization of the resulting force of weight-bearing on the hip joint "R" on the morphological characteristics of the medullar canal on the proximal edge of the shaft of femur was researched. Progressive degenerative changes of the hip joint with a consequent sideways limping or changes of the collodiaphysial angle (ccd angle) were the cause of the verticalization of the resulting force "R". The analysis of patients treated and operated on The Orthopaedic Department of the General Hospital Osijek and The Orthopaedic Clinic of The Medical Faculty of The University of Zagreb. The research, undoubtedly, proved that the patients with coxarthrosis and side-ways in the hip or with changed collodiaphysial angle experienced verticalization of the resulting force of weigh-bearing of the hip joint and the proximal edge of femur which caused morphological changes of the medular canal of the shaft of femur.

The influence of lower leg configurations on muscle force variability.

Science.gov (United States)

Ofori, Edward; Shim, Jaeho; Sosnoff, Jacob J

2018-04-11

The maintenance of steady contractions is required in many daily tasks. However, there is little understanding of how various lower limb configurations influence the ability to maintain force. The purpose of the current investigation was to examine the influence of joint angle on various lower-limb constant force contractions. Nineteen adults performed knee extension, knee flexion, and ankle plantarflexion isometric force contractions to 11 target forces, ranging from 2 to 95% maximal voluntary contraction (MVC) at 2 angles. Force variability was quantified with mean force, standard deviation, and the coefficient of variation of force output. Non-linearities in force output were quantified with approximate entropy. Curve fitting analyses were performed on each set of data from each individual across contractions to further examine whether joint angle interacts with global functions of lower-limb force variability. Joint angle had significant effects on the model parameters used to describe the force-variability function for each muscle contraction (p force output were more explained by force level in smaller angle conditions relative to the larger angle conditions (p force production. Biomechanical factors, such as joint angle, along with neurophysiological factors should be considered together in the discussion of the dynamics of constant force production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Force-Time Entropy of Isometric Impulse.

Science.gov (United States)

Hsieh, Tsung-Yu; Newell, Karl M

2016-01-01

The relation between force and temporal variability in discrete impulse production has been viewed as independent (R. A. Schmidt, H. Zelaznik, B. Hawkins, J. S. Frank, & J. T. Quinn, 1979 ) or dependent on the rate of force (L. G. Carlton & K. M. Newell, 1993 ). Two experiments in an isometric single finger force task investigated the joint force-time entropy with (a) fixed time to peak force and different percentages of force level and (b) fixed percentage of force level and different times to peak force. The results showed that the peak force variability increased either with the increment of force level or through a shorter time to peak force that also reduced timing error variability. The peak force entropy and entropy of time to peak force increased on the respective dimension as the parameter conditions approached either maximum force or a minimum rate of force production. The findings show that force error and timing error are dependent but complementary when considered in the same framework with the joint force-time entropy at a minimum in the middle parameter range of discrete impulse.

Synthesis and photocatalytic activity of mesoporous – (001) facets TiO_2 single crystals

International Nuclear Information System (INIS)

Dong, Yeshuo; Fei, Xuening; Zhou, Yongzhu

2017-01-01

Highlights: • The (001) facets of TiO_2 single crystals with mesoporous structure. • The (010) and (100) facets of TiO_2 single crystals were covered by the flower – shaped TiO_2 crystals. • This special structure could promote charge separation and provide more active sites, which will lead to a substantial increase in photocatalytic activity. - Abstract: In this work, the mesoporous – (001) facets TiO_2 single crystals have been successfully synthesized through a two-step solvothermal route without any template. Their structure and morphology were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV–vis) diffuse reflectance spectroscopy and energy dispersive X-ray spectrometer (EDX). Based on the different characteristics and atomic arrangements on each facet of anatase TiO_2 single crystals, we synthesized these mesoporous – (001) facets TiO_2 single crystals by controlling the interaction characteristics of hydrofluoric acid (HF) and isopropanol (i-PrOH) on the crystal facets. It can been seen that the (001) facets of these as-synthesized TiO_2 single crystals have a clear mesoporous structure through the SEM images and BET methods. Moreover, the other four facets were covered by the flower – shaped TiO_2 crystals with the generation of the mesoporous – (001) facets. This special and interesting morphology could promote charge separation and provide more active sites, which will lead to a substantial increase in photocatalytic activity. Moreover, it is more intuitive to reflect that the different crystal facets possess the different properties due to their atomic arrangement. Besides, according to the different synthetic routes, we proposed and discussed a plausible synthesis mechanism of these mesoporous – (001) facets TiO_2 single crystals.

Local facet approximation for image stitching

Science.gov (United States)

Li, Jing; Lai, Shiming; Liu, Yu; Wang, Zhengming; Zhang, Maojun

2018-01-01

Image stitching aims at eliminating multiview parallax and generating a seamless panorama given a set of input images. This paper proposes a local adaptive stitching method, which could achieve both accurate and robust image alignments across the whole panorama. A transformation estimation model is introduced by approximating the scene as a combination of neighboring facets. Then, the local adaptive stitching field is constructed using a series of linear systems of the facet parameters, which enables the parallax handling in three-dimensional space. We also provide a concise but effective global projectivity preserving technique that smoothly varies the transformations from local adaptive to global planar. The proposed model is capable of stitching both normal images and fisheye images. The efficiency of our method is quantitatively demonstrated in the comparative experiments on several challenging cases.

Joint Force Quarterly. Number 30, Spring 2002

Science.gov (United States)

2002-05-01

Clemmons , USA ■ National War College A. Denis Clift ■ Joint Military Intelligence College RADM David R. Ellison, USN ■ Naval Postgraduate School BG Mark P...to determine the main axis of the German advance [General Maurice ] Gamelin dislocated his strategic reserves by committing the French Seventh Army to

Optical fiber end-facet polymer suspended-mirror devices

Science.gov (United States)

Yao, Mian; Wu, Jushuai; Zhang, A. Ping; Tam, Hwa-Yaw; Wai, P. K. A.

2017-04-01

This paper presents a novel optical fiber device based on a polymer suspended mirror on the end facet of an optical fiber. With an own-developed optical 3D micro-printing technology, SU-8 suspended-mirror devices (SMDs) were successfully fabricated on the top of a standard single-mode optical fiber. Optical reflection spectra of the fabricated SU- 8 SMDs were measured and compared with theoretical analysis. The proposed technology paves a way towards 3D microengineering of the small end-facet of optical fibers to develop novel fiber-optic sensors.

Restructuring to Achieve Joint Engineer Integration and Transformation

National Research Council Canada - National Science Library

Kelly, Paul

2003-01-01

.... Increased joint engineer operations, including new homeland defense support requirements, transformation of the joint force, and the growing need for efficient use of scarce engineer resources...

Theater Logistics Management: A Case for a Joint Distribution Solution

National Research Council Canada - National Science Library

Garcia, Jr, Mario V

2008-01-01

...) and Joint Force Commanders (JFC). It explores the factors affecting theater distribution and joint theater logistics management including Joint Reception Staging Onward Movement and Integration (JRSOI) operations...

Buckling behavior of origami unit cell facets under compressive loads

Science.gov (United States)

Kshad, Mohamed Ali Emhmed; Naguib, Hani E.

2018-03-01

Origami structures as cores for sandwich structures are designed to withstand the compressive loads and to dissipate compressive energy. The deformation of the origami panels and the unit cell facets are the primary factors behind the compressive energy dissipation in origami structures. During the loading stage, the origami structures deform through the folding and unfolding process of the unit cell facets, and also through the plastic deformation of the facets. This work presents a numerical study of the buckling behavior of different origami unit cell elements under compressive loading. The studied origami configurations were Miura and Ron-Resch-like origami structures. Finite element package was used to model the origami structures. The study investigated the buckling behavior of the unit cell facets of two types of origami structures Miura origami and Ron-Resch-Like origami structures. The simulation was conducted using ANSYS finite element software, in which the model of the unit cell represented by shell elements, and the eigenvalues buckling solver was used to predict the theoretical buckling of the unit cell elements.

Control of compliant anthropomimetic robot joint

Directory of Open Access Journals (Sweden)

Svetozarević Bratislav

2011-01-01

Full Text Available In this paper we propose a control strategy for a robot joint which fully mimics the typical human joint structure. The joint drive is based on two actuators (dc motors, agonist and antagonist, acting through compliant tendons and forming a nonlinear multi-input multi-output (MIMO system. At any time, we consider one actuator, the puller, as being responsible for motion control, while the role of the other is to keep its tendon force at some appropriate low level. This human-like and energetically efficient approach requires the control of 'switching', or exchanging roles between actuators. Moreover, an algorithm based on adaptive force reference is used to solve a problem of slacken tendons during the switching and to increase the energy efficiency. This approach was developed and evaluated on increasingly complex robot joint configurations, starting with simple and noncompliant system, and finishing with nonlinear and compliant system.

Joint Force Quarterly. Number 7, Spring 1995

Science.gov (United States)

1995-02-01

agencies which use canines . The Air Force also operates a law enforcement school at Lackland for Navy and Air Force “cops.” In ad- dition, English...were not moving as quickly as marines. This incident caused a debate that rages to this day. On Guam, however, the Army (77th Di- vision) and the

Joint Force Quarterly. Number 25, Summer 2000

Science.gov (United States)

2000-09-01

and Staff College Brig Gen Richard B. Bundy, USAF ■ The Joint Staff VADM Arthur K. Cebrowski, USN ■ Naval War College MG Reginal G. Clemmons , USA...1930s, General Maurice Gamelin, established the high command as the sole arbiter of doctrine early in his tenure. From that point, all articles, books

Fiber facet gratings for high power fiber lasers

Science.gov (United States)

Vanek, Martin; Vanis, Jan; Baravets, Yauhen; Todorov, Filip; Ctyroky, Jiri; Honzatko, Pavel

2017-12-01

We numerically investigated the properties of diffraction gratings designated for fabrication on the facet of an optical fiber. The gratings are intended to be used in high-power fiber lasers as mirrors either with a low or high reflectivity. The modal reflectance of low reflectivity polarizing grating has a value close to 3% for TE mode while it is significantly suppressed for TM mode. Such a grating can be fabricated on laser output fiber facet. The polarizing grating with high modal reflectance is designed as a leaky-mode resonant diffraction grating. The grating can be etched in a thin layer of high index dielectric which is sputtered on fiber facet. We used refractive index of Ta2O5 for such a layer. We found that modal reflectance can be close to 0.95 for TE polarization and polarization extinction ratio achieves 18 dB. Rigorous coupled wave analysis was used for fast optimization of grating parameters while aperiodic rigorous coupled wave analysis, Fourier modal method and finite difference time domain method were compared and used to compute modal reflectance of designed gratings.

Some Results on facets for linear inequality in 0-1 variables

Directory of Open Access Journals (Sweden)

D. Sashi Bhusan

2010-03-01

Full Text Available The facet of Knapsack ploytope, i.e. convex hull of 0-1 points satisfying a given linear inequality has been presented in this current paper. Such type of facets plays an important role in set covering set partitioning, matroidal-intersection vertex- packing, generalized assignment and other combinatorial problems. Strong covers for facets of Knapsack ploytope has been developed in the first part of the present paper. Generating family of valid cutting planes that satisfy inequality with 0-1 variables through algorithms are the attraction of this paper.

The morphological characteristics of the antebrachiocarpal joint of the cheetah (Acinonyx jubatus).

Science.gov (United States)

Ohale, L O C; Groenewald, H B

2003-03-01

A morphological study of the structures of the antebrachiocarpal (AC) joint of the cheetah was carded out by dissection of eight forelimbs obtained from four adult cheetahs culled from the Kruger National Park, Republic of South Africa. The aim was to evaluate the deviations of this joint from the normal feline pattern and to consider their possible relationship to the cheetah's adaptation to speed. Although published data on the AC joint of the other felids show general resemblance to that of the cheetah, there are nevertheless slight, but significant variations and modifications which tend to suggest adaptation to speed. The shafts of the radius and ulna of the cheetah are relatively straight and slender, with poorly developed distal ends. The ulnar notch is reduced to a very shallow concavity while the corresponding ulnar facet is a barely noticeable convexity, separated from the distal ulnar articular facet by an ill-defined groove. The movement of the distal radio-ulnar joint is highly restricted by the presence of a fibro-cartilaginous structure and a strong interrosseous membrane, limiting pronation and supination normally achieved by the rotation of the radius around the ulna. The extensor grooves at the distal extremity of the radius are deep and narrow and are guarded by prominent ridges. A thick extensor retinaculum anchors the strong extensor tendons in these grooves. The distal articular surface of the radius is concave in all directions except at the point where it moves into its stylold process. At this point it is convex in the dorsopalmar direction, with a surface that is rather deep and narrow. The proximal row of carpal bones presents a strongly convex surface, which is more pronounced in the dorsopalmar direction with the greatest convexity on the lateral aspect. Medially, there is a ridge-like concavity across the base of the tubercle, which rocks on the flexor surface of the radius, limiting excessive flexion as well as restricting lateral

[Features of the new minimally invasive techniques facet fixation system «Facet Wedge» in the treatment of degenerative diseases of the lumbar spine in elderly patients.

Science.gov (United States)

Byvaltsev, V A; Kalinin, A A; Okoneshnikova, A K

2017-01-01

The aim of the study was a comparative analysis of the clinical and radiographic effectiveness of the use of interbody fusion and open pedicle screw stabilization of simultaneous and new minimally invasive techniques facet fixation system «Facet Wedge» in the treatment of degenerative diseases of the lumbar spine in elderly patients. The study included 39 elderly patients (older than 60), which carries out the transforaminal interbody fusion Cage «T-pal»: open transpedicaular stabilization was used in 1st group (n=23), ipsilateral open transpedicular stabilization with contralateral transfaset installing titanium Cage «facet Wedge» -in 2nd group (n=16). We used intraoperative interventions and specific post-operative patient management, clinical data and radiographic outcomes for a comparative analysis of the parameters. Dynamic assessment was made in a period of 8 to 36 months after surgery (median 24 mo.). As a result, it found that the use of the system «facet Wedge» allows you to achieve the best clinical outcomes and fewer postoperative complications compared with open transpedicular stabilization in similar radiographic findings of bone block formation. Low traumatic facet fixation makes it possible to use methods for the treatment of elderly patients with degenerative diseases of the lumbosacral spine.

Influence of the size of facets on point focus solar concentrators

Energy Technology Data Exchange (ETDEWEB)

Riveros-Rosas, David [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Col. Copilco, Coyoacan, CP 04510 DF (Mexico); Sanchez-Gonzalez, Marcelino [Centro Nacional de Energias Renovables, c/Somera 7-9, CP 28026 Madrid (Spain); Arancibia-Bulnes, Camilo A.; Estrada, Claudio A. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/n, Morelos (Mexico)

2011-03-15

It is a common practice in the development of point focus solar concentrators to use multiple identical reflecting facets, as a practical and economic alternative for the design and construction of large systems. This kind of systems behaves in a different manner than continuous paraboloidal concentrators. A theoretical study is carried out to understand the effect of the size of facets and of their optical errors in multiple facet point focus solar concentrating systems. For this purpose, a ray tracing program was developed based on the convolution technique, in which the brightness distribution of the sun and the optical errors of the reflecting surfaces are considered. The study shows that both the peak of concentration and the optimal focal distance of the system strongly depend on the size of the facets, and on their optical errors. These results are useful to help concentrator developers to have a better understanding of the relationship between manufacturing design restrictions and final optical behavior. (author)

Facets of emotional awareness and associations with emotion regulation and depression.

Science.gov (United States)

Boden, Matthew Tyler; Thompson, Renee J

2015-06-01

Emotion theories posit that effective emotion regulation depends upon the nuanced information provided by emotional awareness; attending to and understanding one's own emotions. Additionally, the strong associations between facets of emotional awareness and various forms of psychopathology may be partially attributable to associations with emotion regulation. These logically compelling hypotheses are largely uninvestigated, including which facets compose emotional awareness and how they relate to emotion regulation strategies and psychopathology. We used exploratory structural equation modeling of individual difference measures among a large adult sample (n = 919) recruited online. Results distinguished 4 facets of emotional awareness (type clarity, source clarity, involuntary attention to emotion, and voluntary attention to emotion) that were differentially associated with expressive suppression, acceptance of emotions, and cognitive reappraisal. Facets were associated with depression both directly and indirectly via associations with emotion regulation strategies. We discuss implications for theory and research on emotional awareness, emotion regulation, and psychopathology. (c) 2015 APA, all rights reserved).

Job Stress, Employee Health, and Organizational Effectiveness: A Facet Analysis, Model, and Literature Review.

Science.gov (United States)

Beehr, Terry A.; Newman, John E.

1978-01-01

The empirical research on job stress and employee health is reviewed within the context of six facets (environmental, personal, process, human consequences, organizational consequences, and time) of a seven facet conceptualization of the job stress-employee health research domain. Models are proposed for tying the facets together. (Author/SJL)

Hip and knee joint loading during vertical jumping and push jerking.

Science.gov (United States)

Cleather, Daniel J; Goodwin, Jon E; Bull, Anthony M J

2013-01-01

The internal joint contact forces experienced at the lower limb have been frequently studied in activities of daily living and rehabilitation activities. In contrast, the forces experienced during more dynamic activities are not well understood, and those studies that do exist suggest very high degrees of joint loading. In this study a biomechanical model of the right lower limb was used to calculate the internal joint forces experienced by the lower limb during vertical jumping, landing and push jerking (an explosive exercise derived from the sport of Olympic weightlifting), with a particular emphasis on the forces experienced by the knee. The knee experienced mean peak loadings of 2.4-4.6×body weight at the patellofemoral joint, 6.9-9.0×body weight at the tibiofemoral joint, 0.3-1.4×body weight anterior tibial shear and 1.0-3.1×body weight posterior tibial shear. The hip experienced a mean peak loading of 5.5-8.4×body weight and the ankle 8.9-10.0×body weight. The magnitudes of the total (resultant) joint contact forces at the patellofemoral joint, tibiofemoral joint and hip are greater than those reported in activities of daily living and less dynamic rehabilitation exercises. The information in this study is of importance for medical professionals, coaches and biomedical researchers in improving the understanding of acute and chronic injuries, understanding the performance of prosthetic implants and materials, evaluating the appropriateness of jumping and weightlifting for patient populations and informing the training programmes of healthy populations. Copyright © 2012 Elsevier Ltd. All rights reserved.

A practical scale for Multi-Faceted Organizational Health Climate Assessment.

Science.gov (United States)

Zweber, Zandra M; Henning, Robert A; Magley, Vicki J

2016-04-01

The current study sought to develop a practical scale to measure 3 facets of workplace health climate from the employee perspective as an important component of a healthy organization. The goal was to create a short, usable yet comprehensive scale that organizations and occupational health professionals could use to determine if workplace health interventions were needed. The proposed Multi-faceted Organizational Health Climate Assessment (MOHCA) scale assesses facets that correspond to 3 organizational levels: (a) workgroup, (b) supervisor, and (c) organization. Ten items were developed and tested on 2 distinct samples, 1 cross-organization and 1 within-organization. Exploratory and confirmatory factor analyses yielded a 9-item, hierarchical 3-factor structure. Tests confirmed MOHCA has convergent validity with related constructs, such as perceived organizational support and supervisor support, as well as discriminant validity with safety climate. Lastly, criterion-related validity was found between MOHCA and health-related outcomes. The multi-faceted nature of MOHCA provides a scale that has face validity and can be easily translated into practice, offering a means for diagnosing the shortcomings of an organization or workgroup's health climate to better plan health and well-being interventions. (c) 2016 APA, all rights reserved).

Evaluation of the magnitude of hip joint deformation in subjects with avascular necrosis of the hip joint during walking with and without Scottish Rite orthosis.

Science.gov (United States)

Karimi, Mohammad Taghi; Mohammadi, Ali; Ebrahimi, Mohammad Hossein; McGarry, Anthony

2017-02-01

The femoral head in subjects with leg calve perthes disease (LCPD) is generally considerably deformed. It is debatable whether this deformation is due to an increase in applied loads, a decrease in bone mineral density or a change in containment of articular surfaces. The aim of this study was to determine the influence of these factors on deformation of the femoral head. Two subjects with LCPD participated in this study. Subject motion and the forces applied on the affected leg were recorded using a motion analysis system (Qualsis TM ) and a Kistler force plate. OpenSim software was used to determine joint contact force of the hip joint whilst walking with and without a Scottish Rite orthosis. 3D Models of hip joints of both subjects were produced by Mimics software. The deformation of femoral bone was determined by Abaqus. Mean values of the force applied on the leg increased while walking with the orthosis. There was no difference between bone mineral density (BMD) of the femoral bone of normal and LCPD sides (p-value>0.05) and no difference between hip joint contact force of normal and LCPD sides. Hip joint containment appeared to decrease follow the use of the orthosis. It can be concluded that the deformation of femoral head in LCPD may not be due to change in BMD or applied load. Although the Scottish Rite orthosis is used mostly to increase hip joint containment, it appears to reduce hip joint contact area. It is recommended that a similar study is conducted using a higher number of subjects. Copyright © 2016 IPEM. All rights reserved.

Progress report for FACETS (Framework Application for Core-Edge Transport Simulations): C.S. SAP

Energy Technology Data Exchange (ETDEWEB)

Epperly, T W

2008-10-01

The mission of the Computer Science Scientific Application Partnership (C.S. SAP) at LLNL is to develop and apply leading-edge scientific component technology to FACETS software. Contributions from LLNL's fusion energy program staff towards the underlying physics modules are described in a separate report. FACETS uses component technology to combine selectively multiple physics and solver software modules written in different languages by different institutions together in an tightly-integrated, parallel computing framework for Tokamak reactor modeling. In the past fiscal year, the C.S. SAP has focused on two primary tasks: applying Babel to connect UEDGE into the FACETS framework through UEDGE's existing Python interface and developing a next generation componentization strategy for UEDGE which avoids the use of Python. The FACETS project uses Babel to solve its language interoperability challenges. Specific accomplishments for the year include: (1) Refined SIDL interfaces for UEDGE to meet satisfy the standard interfaces required by FACETS for all physics modules. This required consensus building between framework and UEDGE developers. (2) Wrote prototype C++ driver for UEDGE to demonstrate how UEDGE can be called from C++ using Babel. (3) Supported the FACETS project by adding new features to Babel such as release number tagging, porting to new machines, and adding new configuration options. Babel modifications were delivered to FACETS by testing and publishing development snapshots in the projects software repository. (4) Assisted Tech-X Corporation in testing and debugging of a high level build system for the complete FACETS tool chain--the complete list of third-party software libraries that FACETS depends on directly or indirectly (e.g., MPI, HDF5, PACT, etc.). (5) Designed and implemented a new approach to wrapping UEDGE as a FACETS component without requiring Python. To get simulation results as soon as possible, our initial connection from the

Progress report for FACETS (Framework Application for Core-Edge Transport Simulations): C.S. SAP

International Nuclear Information System (INIS)

Epperly, T.W.

2008-01-01

The mission of the Computer Science Scientific Application Partnership (C.S. SAP) at LLNL is to develop and apply leading-edge scientific component technology to FACETS software. Contributions from LLNL's fusion energy program staff towards the underlying physics modules are described in a separate report. FACETS uses component technology to combine selectively multiple physics and solver software modules written in different languages by different institutions together in an tightly-integrated, parallel computing framework for Tokamak reactor modeling. In the past fiscal year, the C.S. SAP has focused on two primary tasks: applying Babel to connect UEDGE into the FACETS framework through UEDGE's existing Python interface and developing a next generation componentization strategy for UEDGE which avoids the use of Python. The FACETS project uses Babel to solve its language interoperability challenges. Specific accomplishments for the year include: (1) Refined SIDL interfaces for UEDGE to meet satisfy the standard interfaces required by FACETS for all physics modules. This required consensus building between framework and UEDGE developers. (2) Wrote prototype C++ driver for UEDGE to demonstrate how UEDGE can be called from C++ using Babel. (3) Supported the FACETS project by adding new features to Babel such as release number tagging, porting to new machines, and adding new configuration options. Babel modifications were delivered to FACETS by testing and publishing development snapshots in the projects software repository. (4) Assisted Tech-X Corporation in testing and debugging of a high level build system for the complete FACETS tool chain--the complete list of third-party software libraries that FACETS depends on directly or indirectly (e.g., MPI, HDF5, PACT, etc.). (5) Designed and implemented a new approach to wrapping UEDGE as a FACETS component without requiring Python. To get simulation results as soon as possible, our initial connection from the FACETS

BIOMECHANICS AND PATHOMECHANICS OF THE PATELLOFEMORAL JOINT

Science.gov (United States)

2016-01-01

The patellofemoral joint is a joint that can be an area of concern for athletes of various sports and ages. The joint is somewhat complex with multiple contact points and numerous tissues that attach to the patella. Joint forces are variable and depend on the degree of knee flexion and whether the foot is in contact with the ground. The sports medicine specialist must have a good working knowledge of the anatomy and biomechanics of the patellofemoral joint in order to treat it effectively. PMID:27904787

The Biomechanics of Cranial Forces During Figure Skating Spinning Elements.

Science.gov (United States)

Wang, David H; Kostyun, Regina O; Solomito, Matthew J

2015-03-01

Several facets of figure skating, such as the forces associated with jumping and landing, have been evaluated, but a comprehensive biomechanical understanding of the cranial forces associated with spinning has yet to be explored. The purpose of this case study was to quantify the cranial rotational acceleration forces generated during spinning elements. This case report was an observational, biomechanical analysis of a healthy, senior-level, female figure skating athlete who is part of an on-going study. A triaxial accelerometer recorded the gravitational forces (G) during seven different spinning elements. Our results found that the layback spin generated significant cranial force and these forces were greater than any of the other spin elements recorded. These forces led to physical findings of ruptured capillaries, dizziness, and headaches in our participant.

Surface Area of Patellar Facets: Inferential Statistics in the Iraqi Population

Directory of Open Access Journals (Sweden)

Ahmed Al-Imam

2017-01-01

Full Text Available Background. The patella is the largest sesamoid bone in the body; its three-dimensional complexity necessitates biomechanical perfection. Numerous pathologies occur at the patellofemoral unit which may end in degenerative changes. This study aims to test the presence of statistical correlation between the surface areas of patellar facets and other patellar morphometric parameters. Materials and Methods. Forty dry human patellae were studied. The morphometry of each patella was measured using a digital Vernier Caliper, electronic balance, and image analyses software known as ImageJ. The patellar facetal surface area was correlated with patellar weight, height, width, and thickness. Results. Inferential statistics proved the existence of linear correlation of total facetal surface area and patellar weight, height, width, and thickness. The correlation was strongest for surface area versus patellar weight. The lateral facetal area was found persistently larger than the medial facetal area, the p value was found to be <0.001 (one-tailed t-test for right patellae, and another significant p value of < 0.001 (one-tailed t-test was found for left patellae. Conclusion. These data are vital for the restoration of the normal biomechanics of the patellofemoral unit; these are to be consulted during knee surgeries and implant designs and can be of an indispensable anthropometric, interethnic, and biometric value.

Cross-cultural evidence for the two-facet structure of pride

Science.gov (United States)

Shi, Yan; Chung, Joanne M.; Cheng, Joey T.; Tracy, Jessica L.; Robins, Richard W.; Chen, Xiao; Zheng, Yong

2016-01-01

Across six studies conducted in Mainland China and South Korea, the present research extended prior findings showing that pride is comprised of two distinct conceptual and experiential facets in the U.S.: a pro-social, achievement-oriented “authentic pride”, and an arrogant, self-aggrandizing “hubristic pride”. This same two-facet structure emerged in Chinese participants’ semantic conceptualizations of pride (Study 1), Chinese and Koreans’ dispositional tendencies to experience pride (Studies 2, 3a, and 3b), Chinese and Koreans’ momentary pride experiences (Studies 3a, 3b, and 5), and Americans’ pride experiences using descriptors derived indigenously in Korea (Study 4). Together, these studies provide the first evidence that the two-facet structure of pride generalizes to cultures with highly divergent views of pride and self-enhancement processes from North America. PMID:27158171

Cross-cultural evidence for the two-facet structure of pride.

Science.gov (United States)

Shi, Yan; Chung, Joanne M; Cheng, Joey T; Tracy, Jessica L; Robins, Richard W; Chen, Xiao; Zheng, Yong

2015-04-01

Across six studies conducted in Mainland China and South Korea, the present research extended prior findings showing that pride is comprised of two distinct conceptual and experiential facets in the U.S.: a pro-social, achievement-oriented "authentic pride", and an arrogant, self-aggrandizing "hubristic pride". This same two-facet structure emerged in Chinese participants' semantic conceptualizations of pride (Study 1), Chinese and Koreans' dispositional tendencies to experience pride (Studies 2, 3a, and 3b), Chinese and Koreans' momentary pride experiences (Studies 3a, 3b, and 5), and Americans' pride experiences using descriptors derived indigenously in Korea (Study 4). Together, these studies provide the first evidence that the two-facet structure of pride generalizes to cultures with highly divergent views of pride and self-enhancement processes from North America.

Exploring the relationship between facets of mindfulness and eating pathology in women.

Science.gov (United States)

Lavender, Jason M; Gratz, Kim L; Tull, Matthew T

2011-01-01

Although researchers have examined the efficacy of acceptance- and mindfulness-based interventions in the treatment of eating disorders, few studies have explored the association between trait mindfulness and eating pathology. Therefore, the purpose of the current investigation was to examine the unique associations between multiple facets of mindfulness (acting with awareness, nonreactivity, nonjudgment, describing, and observing) and eating pathology. Undergraduate women (N = 276) completed the Eating Attitudes Test-26, the Five Facet Mindfulness Questionnaire, and the 21-item version of the Depression Anxiety Stress Scales. A hierarchical regression analysis revealed that four mindfulness facets (awareness, nonreactivity, nonjudgment, and describing) were uniquely associated with eating pathology above and beyond anxiety and depression symptoms. Results are discussed with regard to the potential role of various facets of trait mindfulness in eating pathology as well as the possible utility of mindfulness-based treatments for eating disorders.

Does aquatic exercise reduce hip and knee joint loading? In vivo load measurements with instrumented implants.

Directory of Open Access Journals (Sweden)

Ines Kutzner

Full Text Available Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW. Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36-55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated

Rotational injury of cervical facets: CT analysis of fracture patterns with implications for management and neurologic outcome.

Science.gov (United States)

Shanmuganathan, K; Mirvis, S E; Levine, A M

1994-11-01

Imaging studies of patients with rotational facet injuries of the cervical spine were retrospectively reviewed to determine the prevalence and pattern of associated fractures, to correlate injury pattern with recommended surgical stabilization, and to assess neurologic outcome. Radiographs and CT scans obtained for 40 consecutive patients with rotational facet injuries of the cervical spine during a 70-month period were retrospectively reviewed to determine injury level, presence, and orientation of facet fractures, and concurrent nonfacet injuries. Imaging findings were reviewed to assess the likelihood of instability and to determine the most appropriate stabilization requirement. Medical records were reviewed to ascertain mechanism of injury, initial neurologic deficit, and surgical findings. Among the 40 patients with cervical rotational facet injuries, 11 (27%) had pure unilateral facet dislocation or subluxation without associated fractures, and 29 (73%) had concurrent facet fractures involving the inferior facet of the rotated vertebra (n = 13), the superior facet of the subjacent vertebra (n = 9), or both (n = 7). Injury of the rotated vertebra was unilateral in 22 patients but bilateral in 18 patients. Facet fractures frequently extended into the ipsilateral lamina or articular pillar or both. An avulsion fracture from the posteroinferior aspect of the rotated vertebral body, indicating disk disruption, occurred in 10 patients (25%), and seven patients (17%) had complete isolation of an articular pillar. Facet fractures were confirmed for 27 patients who underwent surgical stabilization. Neurologic deficits developed in 29 (73%) of the 40 patients and included radiculopathy in 11 patients and cord syndromes in 18 patients. Pure dislocation without a facet fracture was more likely to lead to a cord syndrome (p = .006). Cervical rotational facet injuries are often accompanied by facet fractures and bilateral damage of the rotated vertebra. These injuries

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...

Segmental translation after lumbar total disc replacement using Prodisc-L®: associated factors and relation to facet arthrosis.

Science.gov (United States)

Shin, Myung H; Ryu, Kyeong S; Rathi, Nitesh K; Park, Chun K

2017-02-01

Segmental translation after lumbar total disc replacement (TDR) with ProDisc-L® prosthesis frequently observed radiographic findings during follow-up period. However its precise pathomechanism and relation with facet arthrosis have not been investigated yet. This study was performed to evaluate possible factors that affect postoperative segmental translation and to identify its relation with facet joint degeneration after lumbar TDR using ProDisc-L® prosthesis. Thirty-five consecutive patients, who underwent lumbar TDR using ProDisc-L®, completed minimum 24 months follow-up. Segmental translation was assessed postoperatively at 1 month and at least at 24 months by using dynamic plain radiograph. Segmental translation was assessed in relation to patient age, sex, change of functional spinal unit (FSU) height, segmental range of motion (ROM), global lumbar ROM, implanted level, relative prosthesis size and prosthesis position. The comparison of segmental translation between progressive facet arthrosis (PFA) group and non-PFA group was also made. The mean segmental translation was 0.49±0.49 mm at 1 month after surgery and showed significant increase to 0.83±0.78 mm at last follow-up (P=0.014). Change of FSU height, segmental ROM, global lumbar ROM, implanted level and relative size of prosthesis were the significant factors among the variables related to segmental translation that authors assessed (P=0.032, P=0.000, P=0.001, P=0.046 and P=0.042, respectively). There was no significant intergroup difference of mean segmental translation between PFA group and non-PFA group (P=0.586). This study demonstrates that segmental translation after TDR using ProDisc-L® has significant relations with change of FSU height, segmental ROM, global lumbar ROM, implanted level and relative size of prosthesis. With the intergroup comparison, PFA group did not show significant higher segmental translation than non-PFA group.

Introduction to Force-Dependent Kinematics: Theory and Application to Mandible Modeling.

Science.gov (United States)

Skipper Andersen, Michael; de Zee, Mark; Damsgaard, Michael; Nolte, Daniel; Rasmussen, John

2017-09-01

Knowledge of the muscle, ligament, and joint forces is important when planning orthopedic surgeries. Since these quantities cannot be measured in vivo under normal circumstances, the best alternative is to estimate them using musculoskeletal models. These models typically assume idealized joints, which are sufficient for general investigations but insufficient if the joint in focus is far from an idealized joint. The purpose of this study was to provide the mathematical details of a novel musculoskeletal modeling approach, called force-dependent kinematics (FDK), capable of simultaneously computing muscle, ligament, and joint forces as well as internal joint displacements governed by contact surfaces and ligament structures. The method was implemented into the anybody modeling system and used to develop a subject-specific mandible model, which was compared to a point-on-plane (POP) model and validated against joint kinematics measured with a custom-built brace during unloaded emulated chewing, open and close, and protrusion movements. Generally, both joint models estimated the joint kinematics well with the POP model performing slightly better (root-mean-square-deviation (RMSD) of less than 0.75 mm for the POP model and 1.7 mm for the FDK model). However, substantial differences were observed when comparing the estimated joint forces (RMSD up to 24.7 N), demonstrating the dependency on the joint model. Although the presented mandible model still contains room for improvements, this study shows the capabilities of the FDK methodology for creating joint models that take the geometry and joint elasticity into account.

U.S. Joint Special Operations Forces: Two Few, Overworked, Young, Homogenous & Macho to Fulfill the Unconventional Demands of the Long War?

Science.gov (United States)

2008-05-28

OVERWORKED , YOUNG, HOMOGENOUS, & MACHO TO FULFILL THE UNCONVENTIONAL DEMANDS OF THE LONG WAR? SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR...U.S. Joint Special Operations Forces: Two Few, Overworked , Young, Homogenous & Macho to Fulfill the Unconventional Demands of the Long War? 5a...to be the targets of nearly daily mortar, improvised explosive devices (IEDs), and occasional suicide vehicle-borne IED (SVBIED) attacks. It

Controlled synthesis and facets-dependent photocatalysis of TiO2 nanocrystals

Science.gov (United States)

Roy, Nitish; Park, Yohan; Sohn, Youngku; Pradhan, Debabrata

2015-04-01

Titanium dioxide (TiO2) is a wide band gap semiconductor that has been extensively used in several environmental applications including degradation of organic hazardous chemicals, water splitting to generate hydrogen, dye sensitized solar cells, self cleaning agents, and pigments. Herein we demonstrate the synthesis of TiO2 nanocrystals (NCs) with the shapes of ellipsoids, rods, cuboids, and sheets with different exposed facets using a noncorrosive and nontoxic chemical (i.e. diethanolamine) as the shape controlling agent, unlike hydrofluoric acid commonly used. The TiO2 NCs of diverse shapes with different exposed facets were tested for photocatalytic hydroxyl radical (OH•) formation, which determines their photocatalytic behavior and the results were compared with the standard P-25 Degussa. The formation rate of OH• per specific surface area was found to be >6 fold higher for rod-shaped TiO2 NCs than that of commercial Degussa P25 catalyst. The highest photocatalytic activity of rod-shaped TiO2 NCs is ascribed to the unique chemical environment of {010} exposed facets which facilitates the electron/hole separation in presence of {101} facets.

CO-CO coupling on Cu facets: Coverage, strain and field effects

International Nuclear Information System (INIS)

Sandberg, Robert B.; Montoya, Joseph H.; Chan, Karen; Nørskov, Jens K.

2016-01-01

We present a DFT study on the effect of coverage, strain, and electric field on CO-CO coupling energetics on Cu (100), (111), and (211). Our calculations indicate that CO-CO coupling is facile on all three facets in the presence of a cation-induced electric field in the Helmholtz plane, with the lowest barrier on Cu(100). The CO dimerization pathway is therefore expected to play a role in C_2 formation at potentials negative of the Cu potential of zero charge, corresponding to CO_2/CO reduction conditions at high pH. Both increased *CO coverage and tensile strain further improve C-C coupling energetics on Cu (111) and (211). Since CO dimerization is facile on all 3 Cu facets, subsequent surface hydrogenation steps may also play an important role in determining the overall activity towards C_2 products. Adsorption of *CO, *H, and *OH on the 3 facets were investigated with a Pourbaix analysis. Here, the (211) facet has the largest propensity to co-adsorb *CO and *H, which would favor surface hydrogenation following CO dimerization.

Faceting of stepped silicon (1 1 3) surfaces: Self assembly of nanoscale gratings

Science.gov (United States)

Mochrie, S. G. J.; Song, S.; Yoon, Mirang; Abernathy, D. L.; Stephenson, G. B.

1996-02-01

Synchrotron X-ray scattering studies of the phase behavior and phase transformations of stepped Si(113) surfaces tilted towards [001] are reviewed for temperatures between 300 and 1500 K. At the highest temperatures, these surfaces are uniformly stepped, and the intensity of near-specularly scattered X-rays increases with decreasing temperature. This is two-dimensional critical opalescence, which foreshadows a faceting transformation. At temperatures below the faceting transformation, (113) facets appear in coexistence with a stepped phase, leading to a mesoscopically grooved morphology. Both the misorientation angle at the phase boundary separating one- and two-phase regions and the intensity of the near-specular diffuse scattering may be described as power laws versus reduced temperature. This can be understood qualitatively on the basis of a mean-field theory, which incorporates an attractive interaction between steps. At lower temperatures, the surfaces are completely faceted, comprising (114) and (113) facets. The kinetics of faceting is also described. Following a quench from a one-phase region of the phase diagram into a two-phase region, the grooved superstructure forms and subsequently coarsens in time. For times between one and several hundred seconds, the surface morphology is self-similar at different times, with a characteristic groove size that evolves as a power law versus time. At later times, the groove size approaches a limiting value, as a result of elastic effects.

Virtual ellipsometry on layered micro-facet surfaces.

Science.gov (United States)

Wang, Chi; Wilkie, Alexander; Harcuba, Petr; Novosad, Lukas

2017-09-18

Microfacet-based BRDF models are a common tool to describe light scattering from glossy surfaces. Apart from their wide-ranging applications in optics, such models also play a significant role in computer graphics for photorealistic rendering purposes. In this paper, we mainly investigate the computer graphics aspect of this technology, and present a polarisation-aware brute force simulation of light interaction with both single and multiple layered micro-facet surfaces. Such surface models are commonly used in computer graphics, but the resulting BRDF is ultimately often only approximated. Recently, there has been work to try to make these approximations more accurate, and to better understand the behaviour of existing analytical models. However, these brute force verification attempts still emitted the polarisation state of light and, as we found out, this renders them prone to mis-estimating the shape of the resulting BRDF lobe for some particular material types, such as smooth layered dielectric surfaces. For these materials, non-polarising computations can mis-estimate some areas of the resulting BRDF shape by up to 23%. But we also identified some other material types, such as dielectric layers over rough conductors, for which the difference turned out to be almost negligible. The main contribution of our work is to clearly demonstrate that the effect of polarisation is important for accurate simulation of certain material types, and that there are also other common materials for which it can apparently be ignored. As this required a BRDF simulator that we could rely on, a secondary contribution is that we went to considerable lengths to validate our software. We compare it against a state-of-art model from graphics, a library from optics, and also against ellipsometric measurements of real surface samples.

Patterns of astragalar fibular facet orientation in extant and fossil primates and their evolutionary implications.

Science.gov (United States)

Boyer, Doug M; Seiffert, Erik R

2013-07-01

A laterally sloping fibular facet of the astragalus (=talus) has been proposed as one of few osteological synapomorphies of strepsirrhine primates, but the feature has never been comprehensively quantified. We describe a method for calculating fibular facet orientation on digital models of astragali as the angle between the planes of the fibular facet and the lateral tibial facet. We calculated this value in a sample that includes all major extant primate clades, a diversity of Paleogene primates, and nonprimate euarchontans (n = 304). Results show that previous characterization of a divide between extant haplorhines and strepsirrhines is accurate, with little overlap even when individual data points are considered. Fibular facet orientation is conserved in extant strepsirrhines despite major differences in locomotion and body size, while extant anthropoids are more variable (e.g., low values for catarrhines relative to non-callitrichine platyrrhines). Euprimate outgroups exhibit a mosaic of character states with Cynocephalus having a more obtuse strepsirrhine-like facet and sampled treeshrews and plesiadapiforms having more acute haplorhine-like facets. Surprisingly, the earliest species of the adapiform Cantius have steep haplorhine-like facets as well. We used a Bayesian approach to reconstruct the evolution of fibular facet orientation as a continuous character across a supertree of living and extinct primates. Mean estimates for crown Primatomorpha (97.9°), Primates (99.5°), Haplorhini (98.7°), and Strepsirrhini (108.2°) support the hypothesis that the strepsirrhine condition is derived, while lower values for crown Anthropoidea (92.8°) and Catarrhini (88.9°) are derived in the opposite direction. Copyright © 2013 Wiley Periodicals, Inc.

US/UK Sensor-To-Shooter Multinational C4 Interoperability Study Force-On-Force Effectiveness Methodology

National Research Council Canada - National Science Library

Bailey, Timothy J

2000-01-01

.... This methodology has been successfully applied to Army, joint, and multinational studies. The latest of these studies, the US/UK Sensor-To-Shooter Multinational C4 Interoperability Study Force-On-Force Analysis, was an effort to measure the value...

Modulation of shoulder muscle and joint function using a powered upper-limb exoskeleton.

Science.gov (United States)

Wu, Wen; Fong, Justin; Crocher, Vincent; Lee, Peter V S; Oetomo, Denny; Tan, Ying; Ackland, David C

2018-04-27

Robotic-assistive exoskeletons can enable frequent repetitive movements without the presence of a full-time therapist; however, human-machine interaction and the capacity of powered exoskeletons to attenuate shoulder muscle and joint loading is poorly understood. This study aimed to quantify shoulder muscle and joint force during assisted activities of daily living using a powered robotic upper limb exoskeleton (ArmeoPower, Hocoma). Six healthy male subjects performed abduction, flexion, horizontal flexion, reaching and nose touching activities. These tasks were repeated under two conditions: (i) the exoskeleton compensating only for its own weight, and (ii) the exoskeleton providing full upper limb gravity compensation (i.e., weightlessness). Muscle EMG, joint kinematics and joint torques were simultaneously recorded, and shoulder muscle and joint forces calculated using personalized musculoskeletal models of each subject's upper limb. The exoskeleton reduced peak joint torques, muscle forces and joint loading by up to 74.8% (0.113 Nm/kg), 88.8% (5.8%BW) and 68.4% (75.6%BW), respectively, with the degree of load attenuation strongly task dependent. The peak compressive, anterior and superior glenohumeral joint force during assisted nose touching was 36.4% (24.6%BW), 72.4% (13.1%BW) and 85.0% (17.2%BW) lower than that during unassisted nose touching, respectively. The present study showed that upper limb weight compensation using an assistive exoskeleton may increase glenohumeral joint stability, since deltoid muscle force, which is the primary contributor to superior glenohumeral joint shear, is attenuated; however, prominent exoskeleton interaction moments are required to position and control the upper limb in space, even under full gravity compensation conditions. The modeling framework and results may be useful in planning targeted upper limb robotic rehabilitation tasks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Split Personality: Assessing the Potential for Organizational Identity in Reinforcing U.S. Military Jointness

Science.gov (United States)

2015-07-17

of Identity ...........................................................................................................36 Hybrid -Organizational...force through a theoretical lens, developing a working understanding of military identity. Analysis of the environment will illustrate the hybrid ... departmental civilians, and contractors in the DoD’s employ, and is consistent with CJCS usage. Joint Force. The Joint Force describes a notional

Organizing for Information Operations Within The Joint Task Force

National Research Council Canada - National Science Library

McLaughlin, Lawrence

2003-01-01

.... Joint doctrine defines information operations as a broad range of capabilities and related activities that include operations security, psychological operations, electronic warfare, physical attack...

FACET: A simulation software framework for modeling complex societal processes and interactions

Energy Technology Data Exchange (ETDEWEB)

Christiansen, J. H.

2000-06-02

FACET, the Framework for Addressing Cooperative Extended Transactions, was developed at Argonne National Laboratory to address the need for a simulation software architecture in the style of an agent-based approach, but with sufficient robustness, expressiveness, and flexibility to be able to deal with the levels of complexity seen in real-world social situations. FACET is an object-oriented software framework for building models of complex, cooperative behaviors of agents. It can be used to implement simulation models of societal processes such as the complex interplay of participating individuals and organizations engaged in multiple concurrent transactions in pursuit of their various goals. These transactions can be patterned on, for example, clinical guidelines and procedures, business practices, government and corporate policies, etc. FACET can also address other complex behaviors such as biological life cycles or manufacturing processes. To date, for example, FACET has been applied to such areas as land management, health care delivery, avian social behavior, and interactions between natural and social processes in ancient Mesopotamia.

Design and clinical outcome of a novel 3D-printed prosthetic joint replacement for the human temporomandibular joint.

Science.gov (United States)

Ackland, David; Robinson, Dale; Lee, Peter Vee Sin; Dimitroulis, George

2018-05-11

Stock prosthetic temporomandibular joint replacements come in limited sizes, and do not always encompass the joint anatomy that presents clinically. The aims of this study were twofold. Firstly, to design a personalized prosthetic total joint replacement for the treatment of a patient's end-stage temporomandibular joint osteoarthritis, to implant the prosthesis into the patient, and assess clinical outcome 12-months post-operatively; and secondly, to evaluate the influence of changes in prosthetic condyle geometry on implant load response during mastication. A 48-year-old female patient with Grade-5 osteoarthritis to the left temporomandibular joint was recruited, and a prosthesis developed to match the native temporomandibular joint anatomy. The prosthesis was 3D printed, sterilized and implanted into the patient, and pain and function measured 12-months post-operatively. The prosthesis load response during a chewing-bite and maximum-force bite was evaluated using a personalized multi-body musculoskeletal model. Simulations were performed after perturbing condyle thickness, neck length and head sphericity. Increases in prosthetic condyle neck length malaligned the mandible and perturbed temporomandibular joint force. Changes in condylar component thickness greatly influenced fixation screw stress response, while a more eccentric condylar head increased prosthetic joint-contact loading. Post-operatively, the prosthetic temporomandibular joint surgery reduced patient pain from 7/10 to 1/10 on a visual analog scale, and increased intercisal opening distance from 22 mm to 38 mm. This study demonstrates effectiveness of a personalized prosthesis that may ultimately be adapted to treat a wide-range of end-stage temporomandibular joint conditions, and highlights sensitivity of prosthesis load response to changes in condylar geometry. Copyright © 2018 Elsevier Ltd. All rights reserved.

The HEXACO correlates of authoritarianism's facets in the U.S. and Denmark

DEFF Research Database (Denmark)

Liu, Jie; Ludeke, Steven G.; Zettler, Ingo

2017-01-01

was the predictable differences in the relations the facets had with Honesty-Humility, which was more positively related to conventionalism than authoritarian aggression in the U.S. sample, but not in the Danish sample. Interestingly, the U.S. sample scored significantly higher in authoritarianism and its facets than...

An Examination of the Multi-Faceted Motivation System in Healthy Young Adults

Directory of Open Access Journals (Sweden)

Susana Da Silva

2018-05-01

Full Text Available Background: Amotivation is a prevalent symptom in schizophrenia (SZ and depression (MDD, and is linked to poor functional outcomes in affected individuals. Conceptualizations of motivation have outlined a multi-faceted construct comprised of reward responsiveness, reward expectancy, reward valuation, effort valuation, and action selection/preference-based decision making. To date, findings from studies utilizing variable-centered approaches to examining isolated facets of motivation in SZ and MDD have been inconsistent. Thus, the present study adopted a person-centered approach, and comprehensively examined the reward system in a non-clinical sample in an attempt to explore potential subtypes of motivation impairments, while minimizing the effects of illness-related confounds.Methods: Ninety-six healthy undergraduate students were evaluated for amotivation, schizotypal traits, depressive symptoms, and cognition, and administered objective computerized tasks to measure the different facets of motivation. Cluster analysis was performed to explore subgroups of individuals based on similar motivation task performance. Additionally, correlational analyses were conducted in order to examine inter-relationships between motivation facets, and relations between clinical measures and facets of motivation.Results: Cluster analysis identified two subgroups of individuals with differential motivation performance profiles. Correlational analyses revealed that reward responsiveness was associated with amotivation, depressive symptoms, and negative schizotypy. Further, significant inter-correlations were found between reward responsiveness and reward expectancy, as well as between reward valuation and effort valuation.Conclusions: Our results mark important steps forward in understanding motivation in a non-clinical sample, and guide future dimensional and comprehensive analyses of the multi-faceted reward system. It remains to be seen whether these patterns of

An Examination of the Multi-Faceted Motivation System in Healthy Young Adults.

Science.gov (United States)

Da Silva, Susana; Apatsidou, Areti; Saperia, Sarah; Siddiqui, Ishraq; Jeffay, Eliyas; Voineskos, Aristotle N; Daskalakis, Zafiris J; Remington, Gary; Zakzanis, Konstantine K; Foussias, George

2018-01-01

Background: Amotivation is a prevalent symptom in schizophrenia (SZ) and depression (MDD), and is linked to poor functional outcomes in affected individuals. Conceptualizations of motivation have outlined a multi-faceted construct comprised of reward responsiveness, reward expectancy, reward valuation, effort valuation, and action selection/preference-based decision making. To date, findings from studies utilizing variable-centered approaches to examining isolated facets of motivation in SZ and MDD have been inconsistent. Thus, the present study adopted a person-centered approach, and comprehensively examined the reward system in a non-clinical sample in an attempt to explore potential subtypes of motivation impairments, while minimizing the effects of illness-related confounds. Methods: Ninety-six healthy undergraduate students were evaluated for amotivation, schizotypal traits, depressive symptoms, and cognition, and administered objective computerized tasks to measure the different facets of motivation. Cluster analysis was performed to explore subgroups of individuals based on similar motivation task performance. Additionally, correlational analyses were conducted in order to examine inter-relationships between motivation facets, and relations between clinical measures and facets of motivation. Results: Cluster analysis identified two subgroups of individuals with differential motivation performance profiles. Correlational analyses revealed that reward responsiveness was associated with amotivation, depressive symptoms, and negative schizotypy. Further, significant inter-correlations were found between reward responsiveness and reward expectancy, as well as between reward valuation and effort valuation. Conclusions: Our results mark important steps forward in understanding motivation in a non-clinical sample, and guide future dimensional and comprehensive analyses of the multi-faceted reward system. It remains to be seen whether these patterns of results will

Posterior longitudinal ligament status in cervical spine bilateral facet dislocations

International Nuclear Information System (INIS)

Carrino, John A.; Manton, Geoffrey L.; Morrison, William B.; Flanders, Adam E.; Vaccaro, Alex R.; Schweitzer, Mark E.

2006-01-01

It is generally accepted that cervical spine bilateral facet dislocation results in complete disruption of the posterior longitudinal ligament. The goal of this study was to evaluate the integrity of numerous spine-stabilizing structures by MRI, and to determine if any associations between injury patterns exist with respect to the posterior longitudinal ligament status. Retrospective case series. A retrospective review was performed of 30 cervical spine injury subjects with bilateral facet dislocation. Assessment of 1.5T MRI images was carried out for: intervertebral disc disruption, facet fracture, and ligamentous disruption. Statistical analyses were performed to evaluate for associations between various injury patterns and posterior longitudinal ligament status. The frequency of MRI abnormalities was: anterior longitudinal ligament disruption (26.7%), disc herniation or disruption (90%), posterior longitudinal ligament disruption (40%), facet fracture (63.3%) and disruption of the posterior column ligament complex (97%). There were no significant associations between injury to the posterior longitudinal ligament and other structures. Compared to surgical reports, MRI was accurate for determining the status for 24 of 26 ligaments (three of three anterior longitudinal ligament, seven of nine posterior longitudinal ligament, and 14 of 14 posterior column ligament complex) but generated false negatives in two instances (in both MRI showed an intact posterior longitudinal ligament that was torn at surgery). (orig.)

Dioptrics of the facet lenses in the dorsal rim area of the cricket Gryllus bimaculatus

NARCIS (Netherlands)

Ukhanov, KY; Leertouwer, HL; Gribakin, FG; Stavenga, DG

1996-01-01

1. The optics of the corneal facet lenses from the dorsal rim area (DRA) and from the dorso-lateral areas (DA) of the compound eye of the cricket Gryllus bimaculatus were studied. 2. The DRA of the cricket eye contains quite normally shaped facet lenses. The diameter of the facet lens in the DA is

Posterolateral elbow joint instability

DEFF Research Database (Denmark)

Olsen, Bo Sanderhoff; Søjbjerg, Jens Ole; Nielsen, K K

1998-01-01

Thirty-five osteoligamentous elbows were included in a study on the kinematics of posterolateral elbow joint instability during the pivot shift test (PST) before and after separate ligament cuttings in the lateral collateral ligament complex (LCLC). Division of the annular ligament or the lateral...... ulnar collateral ligament caused no laxity during the PST. Division of the lateral collateral ligament caused maximal laxity of 4 degrees and 23 degrees during forced PST in valgus and external rotation (supination), respectively. Cutting of the LCLC at the ulnar or the humeral insertion was necessary...... for any PST stressed elbow joint laxity to occur. Total division of the LCLC induced a maximal laxity of 7.9 degrees and 37 degrees during forced PST in valgus and external rotation (supination), respectively. This study suggests the lateral collateral ligament to be the primary soft tissue constraint...

Influence of the austenitizing temperature in the cleavage facet size of Niocor 2

International Nuclear Information System (INIS)

Darwish, F.A.I.; Teixeira, J.C.G.; Fernandes, R.A.; Juer, S.

1983-01-01

Convetional Charpy specimens of Niocor 2 steel cooled in air from various austenitizing temperatures were fractured at -196 0 C so as to insure failure by cleavage. The cleavage facet size distribution was determined and then correlated with the grain size and other aspects of the microstructure. The results that the average facet size can be increased through a coarsening of the microstructure. For the case where the γ→α transformation products are predominantely acicular, the facet size is shown to depend on substructural aspects primarily the lath packet size. (Author) [pt

The influence of cadence and shoes on patellofemoral joint kinetics in runners with patellofemoral pain.

Science.gov (United States)

Bonacci, Jason; Hall, Michelle; Fox, Aaron; Saunders, Natalie; Shipsides, Tristan; Vicenzino, Bill

2018-06-01

To determine the effect of a combination of a minimalist shoe and increased cadence on measures of patellofemoral joint loading during running in individuals with patellofemoral pain. Within-participant repeated measures with four conditions presented in random order: (1) control shoe at preferred cadence; (2) control shoe with +10% cadence; (3) minimalist shoe at preferred cadence; (4) minimalist shoe with +10% cadence. Fifteen recreational runners with patellofemoral pain ran on an instrumented treadmill while three-dimensional motion capture data were acquired. Peak patellofemoral joint stress, joint reaction force, knee extensor moment and knee joint angle during the stance phase of running were calculated. One-way repeated measures ANOVA was used to compare the control condition (1) to the three experimental conditions (2-4). Running in a minimalist shoe at an increased cadence reduced patellofemoral stress and joint reaction force on average by approximately 29% (ppatellofemoral joint stress by 15% and joint reaction force by 17% (ppatellofemoral joint stress and joint reaction force by 16% and 19% (ppatellofemoral pain, running in a minimalist shoe at an increased cadence had the greatest reduction in patellofemoral joint loading compared to a control shoe at preferred cadence. This may be an effective intervention to modulate biomechanical factors related to patellofemoral pain. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Contact characteristics of the subtalar joint after a simulated calcaneus fracture.

Science.gov (United States)

Sangeorzan, B J; Ananthakrishnan, D; Tencer, A F

1995-06-01

A simple calcaneus fracture consisting of two parts was modeled in nine fresh cadaver hindfoot specimens to assess changes in subtalar joint contact characteristics with increasing plantar depression of the posterolateral fracture component. To perform the experiment, rods were placed in the tibial and fibular shafts of each specimen, which was mounted in a frame in neutral stance. A pneumatic cylinder was used to deliver a vertical compressive load through the rods into the foot while permitting free motion of the foot in the horizontal plane. Sealed packets of pressure-sensitive film were inserted into the anterior-middle and posterior facets of the talocalcaneal articulation, and a 700-N load was applied. After testing of the intact foot, a primary fracture line was created using a microoscillating saw. The osteotomized posterolateral component was anatomically reduced and fixed, the film inserted, and the load reapplied. The test was repeated after the posterolateral fragment was displaced 2, 5, and 10 mm in a plantar direction. The resulting pressure prints were scanned along with pressure/color density calibration strips using a flat-bed scanner, and an image analysis system was used to determine contact areas within specified pressure intervals. The contact area (> 0.5 MPa) of the posterior facet was significantly decreased with 2, 5, and 10 mm displacements of the posterolateral calcaneus fracture component. The ratio of high-pressure area (< 5.0 MPa) to contact area in the posterior facet was significantly increased only with displacements of 5 and 10 mm. There were no significant changes in any contact parameters in the anterior-middle facet.(ABSTRACT TRUNCATED AT 250 WORDS)

Improving personality facet scores with multidimensional computer adaptive testing: an illustration with the Neo Pi-R

NARCIS (Netherlands)

Makransky, Guido; Mortensen, Erik Lykke; Glas, Cornelis A.W.

2013-01-01

Narrowly defined personality facet scores are commonly reported and used for making decisions in clinical and organizational settings. Although these facets are typically related, scoring is usually carried out for a single facet at a time. This method can be ineffective and time consuming when

Joint Force Quarterly. Number 31, Summer 2002

Science.gov (United States)

2002-09-01

Reginal G. Clemmons , USA ■ National War College A. Denis Clift ■ Joint Military Intelligence College RADM David R. Ellison, USN ■ Naval Postgraduate...commandfigures in a book by thesame title that is too rarelyread today: a memoir of World War II by Maurice Hankey.1 A small, neat, bald man, Hankey...dialogue is conducted. JFQ N O T E S 1 Maurice Hankey, Supreme Command, 2 vols. (London: George Allen and Unwin, 1960). On the issue of supreme command

Big Five Personality Factors and Facets as Predictors of Openness to Diversity.

Science.gov (United States)

Han, Suejung; Pistole, M Carole

2017-11-17

Openness to diversity is a crucial component of cultural competence needed in the increasingly diversified modern society and a necessary condition for benefitting from diversity contacts and interventions (e.g., diversity training, cultural courses). Responding to the recent call for more research on personality and its relation to diversity outcomes, we examined the associations between Big Five personality (i.e., Openness to Experience, Agreeableness, Extraversion, Neuroticism, and Conscientiousness) higher order factors and lower order facets and universal-diverse orientation (i.e., open attitude of appreciating human universality and diversity; Miville et al., 1999 ). In the Study 1 (N = 338) web survey on Big Five factors, Openness to Experience and Agreeableness were associated with universal-diverse orientation significantly. In the Study 2 (N = 176) paper survey on both Big Five factors and facets, Openness to Experience, low Neuroticism, and Conscientiousness, and various lower-order facets of all the Big Five personality were associated with universal-diverse orientation significantly. Practical implications were suggested on how personality facets could be incorporated into current diversity interventions to enhance their effectiveness of promoting openness to diversity.

Unique relationships between facets of mindfulness and eating pathology among female smokers.

Science.gov (United States)

Adams, Claire E; Apperson McVay, Megan; Kinsaul, Jessica; Benitez, Lindsay; Vinci, Christine; Stewart, Diana W; Copeland, Amy L

2012-12-01

Female smokers often have higher levels of eating disorder symptoms than non-smokers, and concerns about eating and weight might interfere with smoking cessation. Thus, it is critical to identify factors to promote healthier eating and body image in this population. Initial research suggests that specific aspects of trait mindfulness predict lower body dissatisfaction and eating disorder symptoms among non-smokers. However, these relationships are unknown among smokers. The current study examined associations between facets of trait mindfulness and eating disorder symptoms in 112 college female smokers (83% Caucasian; mean age 20 years, SD=1.69). After controlling for relevant sociodemographic variables, Describing and Nonjudging facets of mindfulness predicted lower bulimic symptoms and body dissatisfaction (psmindfulness facets are related to lower eating disorder symptoms among smokers, whereas other facets are not associated or have a positive relationship with these symptoms. Mindfulness-based interventions focusing on Describing, Nonjudging, and Acting with Awareness may help to reduce eating pathology among female smokers, which could potentially improve smoking cessation rates in this population. Copyright © 2012 Elsevier Ltd. All rights reserved.

Trait and facet-level predictors of first-onset depressive and anxiety disorders in a community sample of adolescent girls.

Science.gov (United States)

Goldstein, Brandon L; Kotov, Roman; Perlman, Greg; Watson, David; Klein, Daniel N

2017-09-20

Individual differences in neuroticism, extraversion, and conscientiousness are associated with, and may predict onset of, internalizing disorders. These general traits can be parsed into facets, but there is a surprising paucity of research on facet risk for internalizing disorders. We examined general traits and facets of neuroticism, extraversion, and conscientiousness in predicting first onsets of depressive and anxiety disorders. A community sample of 550 adolescent females completed general and facet-level personality measures and diagnostic interviews. Interviews were re-administered 18 months later. First onsets of depressive disorders were predicted by neuroticism, extraversion, and conscientiousness. Facets predicting first onset of depression included depressivity (neuroticism facet) and lower positive emotionality and sociability (extraversion facets). First onsets of generalized anxiety disorder (GAD) were predicted by neuroticism, and particularly the facet of anxiousness. First onsets of social phobia were predicted at the facet level by anxiousness. First onsets of specific phobia were predicted by neuroticism, low conscientiousness, and all neuroticism facets. In multivariate analyses, first onsets of depression were uniquely predicted by depressivity, and onsets of GAD and social phobia were uniquely predicted by anxiousness over and above the general trait of neuroticism. General traits predict first onsets of depressive and anxiety disorders. In addition, more specific associations are evident at the facet level. Facets can refine our understanding of the links between personality and psychopathology risk, and provide finer-grained targets for personality-informed interventions.

Framework Application for Core Edge Transport Simulation (FACETS)

Energy Technology Data Exchange (ETDEWEB)

Krasheninnikov, Sergei; Pigarov, Alexander

2011-10-15

The FACETS (Framework Application for Core-Edge Transport Simulations) project of Scientific Discovery through Advanced Computing (SciDAC) Program was aimed at providing a high-fidelity whole-tokamak modeling for the U.S. magnetic fusion energy program and ITER through coupling separate components for each of the core region, edge region, and wall, with realistic plasma particles and power sources and turbulent transport simulation. The project also aimed at developing advanced numerical algorithms, efficient implicit coupling methods, and software tools utilizing the leadership class computing facilities under Advanced Scientific Computing Research (ASCR). The FACETS project was conducted by a multi-discipline, multi-institutional teams, the Lead PI was J.R. Cary (Tech-X Corp.). In the FACETS project, the Applied Plasma Theory Group at the MAE Department of UCSD developed the Wall and Plasma-Surface Interaction (WALLPSI) module, performed its validation against experimental data, and integrated it into the developed framework. WALLPSI is a one-dimensional, coarse grained, reaction/advection/diffusion code applied to each material boundary cell in the common modeling domain for a tokamak. It incorporates an advanced model for plasma particle transport and retention in the solid matter of plasma facing components, simulation of plasma heat power load handling, calculation of erosion/deposition, and simulation of synergistic effects in strong plasma-wall coupling.

Influence of higher order modes on angled-facet amplifiers

DEFF Research Database (Denmark)

Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian

1991-01-01

The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... of the polarization, even in the presence of a first-order mode with a 15-dB gain. The tolerances for the thickness and refractive index of the AR coating are reduced by a factor of three compared to operation in the fundamental mode only. The influence of the higher order mode can virtually be suppressed...

b-tree facets for the simple graph partitioning polytope

DEFF Research Database (Denmark)

Sørensen, Michael Malmros

2004-01-01

The simple graph partitioning problem is to partition an edge-weighted graph into mutually disjoint subgraphs, each consisting of no more than b nodes, such that the sum of the weights of all edges in the subgraphs is maximal. In this paper we introduce a large class of facet defining inequalities...... for the simple graph partitioning polytopes P_n(b), b >= 3, associated with the complete graph on n nodes. These inequalities are induced by a graph configuration which is built upon trees of cardinality b. We provide a closed-form theorem that states all necessary and sufficient conditions for the facet...... defining property of the inequalities. Udgivelsesdato: JUN...

Norwegian 1990 sediment data for the North Sea Task Force (NSTF) and the Joint Monitoring Group (JMG)

Energy Technology Data Exchange (ETDEWEB)

Green, N.W.; Klungsoeyr, J.

1994-12-31

This report presents the 1990 sediment data compiled as part of the Norwegian contribution to the North Sea Task Force Monitoring Master Plan and the Joint Monitoring Programme (JMP). The JMP is ordered under the Oslo and Paris Commissions, which were established to protect the marine environment against anthropogenic contamination. The stations monitored by Norway are spread over the Kattegat, Skagerrak, North Sea south to the Dogger Bank and the Faeroe Islands. The contaminants investigated are mainly selected metals, organochlorines, polycyclic aromatic hydrocarbons, and the samples were collected by gravity cores and grab/box samplers. The raw data and the mean and standard deviations of parallel samples (if relevant) are presented. 6 refs., 2 tabs.

What’s in a word? : Rethinking facet headings in a discovery service

Directory of Open Access Journals (Sweden)

David Nelson

2015-06-01

Full Text Available The emergence of Discovery systems has been well received by libraries who have long been concerned with offering a smorgasbord of databases that require either individual searching of databases or the problematic use of federated searching.  The ability to search across a wide array of subscribed and open-access information resources via a centralized index has opened up access for users to a library’s wealth of information resources.  This capability has been particularly praised for its ‘google like’ search interface, thereby conforming to user expectations for information searching.  Yet, all discovery services also include facets as a search capability and thus provide faceted navigation which is a search feature that Google is not particularly well suited for.  Discovery services thus provide a hybrid search interface.  An examination of e-commerce sites clearly shows that faceted navigation is an integral part of their discovery systems.  Many library OPACs also now are being developed with faceted navigation capabilities.  However, the discovery services faceted structures suffer from a number of problems which inhibit their usefulness and their potential.  This article examines a number of these issues and it offers suggestions for improving the discovery search interface.  It also argues that vendors and libraries need to work together to more closely analyze the user experience of the discovery system.

Preliminary Conceptual Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

Energy Technology Data Exchange (ETDEWEB)

Hogan, Mark [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2016-04-22

Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes

Polygons and Faceted Polyhedra and Nanoporous Networks.

Science.gov (United States)

Lu, Jianjiang; Mondal, Arunendu; Moulton, Brian; Zaworotko, Michael J

2001-06-01

Small rhombihexahedra and small cubicuboctahedra, namely faceted polyhedra, form the basis of two novel low-density framework solids that are afforded by the self-assembly of molecular squares only or molecular squares and triangles, respectively. © 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

Energy Technology Data Exchange (ETDEWEB)

Abdellatif, M.H. [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Physics Department, National Research Center, Elbehoos st., 12622, Dokki, Giza (Egypt); Salerno, M., E-mail: marco.salerno@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Polovitsyn, Anatolii [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Dipartimentodi Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova (Italy); Marras, Sergio [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); De Angelis, Francesco [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy)

2017-05-01

Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

International Nuclear Information System (INIS)

Abdellatif, M.H.; Salerno, M.; Polovitsyn, Anatolii; Marras, Sergio; De Angelis, Francesco

2017-01-01

Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

The Case for a Joint Evaluation

Science.gov (United States)

2017-01-01

The Capstone Concept of Joint Operations stresses that “the strength of any Joint Force has always been the combining of unique Service...order. Status Quo of Service Evaluations Across the Services, officers’ careers generally begin with a focus on entry- level technical, managerial ...would retain full control of their current evalu- ation systems. However, the Services’ evaluation systems and information would be fed directly

A facet approach to extending the normative component of the theory of reasoned action.

Science.gov (United States)

Donald, I; Cooper, S R

2001-12-01

Using facet theory, this study addresses the weak explanatory power of normative influence in theories of reasoned action or planned behaviour. A broad normative construct is hypothesized as being characterized by two facets--social unit and behavioural modality--each of which is examined in relation to recreational drug use. A questionnaire was developed from the facets and administered to undergraduate students. Data (N = 181) were analysed using Smallest Space Analysis (SSA). The results suggest that the facets provide an adequate description of the normative construct and that personal and social normative beliefs, behavioural norms and behavioural intentions can be distinguished empirically. The results also lend partial support to Ajzen's (1988; Ajzen & Fishbein, 1977) principle of compatibility. Implications for how social influence is operationalized and conceptualized are also discussed.

Predictive Simulations of Neuromuscular Coordination and Joint-Contact Loading in Human Gait.

Science.gov (United States)

Lin, Yi-Chung; Walter, Jonathan P; Pandy, Marcus G

2018-04-18

We implemented direct collocation on a full-body neuromusculoskeletal model to calculate muscle forces, ground reaction forces and knee contact loading simultaneously for one cycle of human gait. A data-tracking collocation problem was solved for walking at the normal speed to establish the practicality of incorporating a 3D model of articular contact and a model of foot-ground interaction explicitly in a dynamic optimization simulation. The data-tracking solution then was used as an initial guess to solve predictive collocation problems, where novel patterns of movement were generated for walking at slow and fast speeds, independent of experimental data. The data-tracking solutions accurately reproduced joint motion, ground forces and knee contact loads measured for two total knee arthroplasty patients walking at their preferred speeds. RMS errors in joint kinematics were joint kinematics, ground forces, knee contact loads and muscle activation patterns measured for slow and fast walking. The results demonstrate the feasibility of performing computationally-efficient, predictive, dynamic optimization simulations of movement using full-body, muscle-actuated models with realistic representations of joint function.

Consensually defined facets of personality as prospective predictors of change in depression symptoms.

Science.gov (United States)

Naragon-Gainey, Kristin; Watson, David

2014-08-01

Depression has robust associations with personality, showing a strong relation with neuroticism and more moderate associations with extraversion and conscientiousness. In addition, each Big Five domain can be decomposed into narrower facets. However, we currently lack consensus as to the contents of Big Five facets, with idiosyncrasies across instruments; moreover, few studies have examined associations with depression. In the current study, community participants completed six omnibus personality inventories; self-reported depressive symptoms were assessed at baseline and 5 years later. Exploratory factor analyses suggested three to five facets in each domain, and these facets served as prospective predictors of depression in hierarchical regressions, after accounting for baseline and trait depression. In these analyses, high anger (from neuroticism), low positive emotionality (extraversion), low conventionality (conscientiousness), and low culture (openness to experiences) were significant prospective predictors of depression. Results are discussed in regard to personality structure and assessment, as well as personality-psychopathology associations. © The Author(s) 2014.

Joint Force Quarterly. Number 9, Autumn 1995

Science.gov (United States)

1995-11-01

Peters, Jr. Production Coordinator Calvin B. Kelley Senior Copy Editor Justin Burkhart Editorial Intern (Summer 1995) The Typography and Design ...J. Rokke ■ C O N T E N T S 2 JFQ / Autumn 1995 ■ O U T O F J O I N T 24 Jointness by Design , Not Accident by Michael C. Vitale ■ J F Q F O R U M...take power, or Iran and Iraq have a free hand, U.S. interests would suffer a serious setback. These factors have altered the region’s geo- graphic

Towards informed and multi-faceted wildlife trade interventions

Directory of Open Access Journals (Sweden)

Daniel W.S. Challender

2015-01-01

Full Text Available International trade in wildlife is a key threat to biodiversity conservation. CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, seeks to ensure international wildlife trade is sustainable, relying on trade bans and controls. However, there has been little comprehensive review of its effectiveness and here we review approaches taken to regulate wildlife trade in CITES. Although assessing its effectiveness is problematic, we assert that CITES boasts few measurable conservation successes. We attribute this to: non-compliance, an over reliance on regulation, lack of knowledge and monitoring of listed species, ignorance of market forces, and influence among CITES actors. To more effectively manage trade we argue that interventions should go beyond regulation and should be multi-faceted, reflecting the complexity of wildlife trade. To inform these interventions we assert an intensive research effort is needed around six key areas: (1 factors undermining wildlife trade governance at the national level, (2 determining sustainable harvest rates for, and adaptive management of CITES species, (3 gaining the buy-in of local communities in implementing CITES, (4 supply and demand based market interventions, (5 means of quantifying illicit trade, and (6 political processes and influence within CITES.

Exploring relations among mindfulness facets and various meditation practices: Do they work in different ways?

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Cebolla, Ausiàs; Campos, Daniel; Galiana, Laura; Oliver, Amparo; Tomás, Jose Manuel; Feliu-Soler, Albert; Soler, Joaquim; García-Campayo, Javier; Demarzo, Marcelo; Baños, Rosa María

2017-03-01

Several meditation practices are associated with mindfulness-based interventions but little is known about their specific effects on the development of different mindfulness facets. This study aimed to assess the relations among different practice variables, types of meditation, and mindfulness facets. The final sample was composed of 185 participants who completed an on-line survey, including information on the frequency and duration of each meditation practice, lifetime practice, and the Five Facet Mindfulness Questionnaire. A Multiple Indicators Multiple Causes structural model was specified, estimated, and tested. Results showed that the Model's overall fit was adequate: χ 2 (1045)=1542.800 (p<0.001), CFI=0.902, RMSEA=0.042. Results revealed that mindfulness facets were uniquely related to the different variables and types of meditation. Our findings showed the importance of specific practices in promoting mindfulness, compared to compassion and informal practices, and they pointed out which one fits each mindfulness facet better. Copyright © 2017 Elsevier Inc. All rights reserved.

Probing the Surface Charge on the Basal Planes of Kaolinite Particles with High-Resolution Atomic Force Microscopy.

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Kumar, N; Andersson, M P; van den Ende, D; Mugele, F; Siretanu, I

2017-12-19

High-resolution atomic force microscopy is used to map the surface charge on the basal planes of kaolinite nanoparticles in an ambient solution of variable pH and NaCl or CaCl 2 concentration. Using DLVO theory with charge regulation, we determine from the measured force-distance curves the surface charge distribution on both the silica-like and the gibbsite-like basal plane of the kaolinite particles. We observe that both basal planes do carry charge that varies with pH and salt concentration. The silica facet was found to be negatively charged at pH 4 and above, whereas the gibbsite facet is positively charged at pH below 7 and negatively charged at pH above 7. Investigations in CaCl 2 at pH 6 show that the surface charge on the gibbsite facet increases for concentration up to 10 mM CaCl 2 and starts to decrease upon further increasing the salt concentration to 50 mM. The increase of surface charge at low concentration is explained by Ca 2+ ion adsorption, while Cl - adsorption at higher CaCl 2 concentrations partially neutralizes the surface charge. Atomic resolution imaging and density functional theory calculations corroborate these observations. They show that hydrated Ca 2+ ions can spontaneously adsorb on the gibbsite facet of the kaolinite particle and form ordered surface structures, while at higher concentrations Cl - ions will co-adsorb, thereby changing the observed ordered surface structure.

Stress radiographs in the evaluation of degenerative femorotibial joint disease

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Tallroth, K.; Lindholm, T.S.

1987-11-01

Thirty-eight osteoarthrotic knees were examined to assess the widths of the femorotibial joint spaces. Radiographs were exposed with the patient lying, in a standing position, and with an adduction and abduction force. Forced compression of the osteoarthrotic joint compartment caused, on average, 18% greater narrowing than when loading it in the standing position. Compared to the joint space at rest, the non-weight-bearing compartment widened by 16% in the standing position and narrowed by 20% when stress was applied. Furthermore, the results showed an increase in laxity proportional to the degree of arthrosis. Stress radiographs significantly display the real cartilage width of both joint compartments. Knowledge of the condition of the articular cartilage in the non-weight-bearing compartment is important when considering a transfer of loading stresses by means of osteotomy. (orig.)

Stress radiographs in the evaluation of degenerative femorotibial joint disease

International Nuclear Information System (INIS)

Tallroth, K.; Lindholm, T.S.

1987-01-01

Thirty-eight osteoarthrotic knees were examined to assess the widths of the femorotibial joint spaces. Radiographs were exposed with the patient lying, in a standing position, and with an adduction and abduction force. Forced compression of the osteoarthrotic joint compartment caused, on average, 18% greater narrowing than when loading it in the standing position. Compared to the joint space at rest, the non-weight-bearing compartment widened by 16% in the standing position and narrowed by 20% when stress was applied. Furthermore, the results showed an increase in laxity proportional to the degree of arthrosis. Stress radiographs significantly display the real cartilage width of both joint compartments. Knowledge of the condition of the articular cartilage in the non-weight-bearing compartment is important when considering a transfer of loading stresses by means of osteotomy. (orig.)

Changes in Chopart joint load following tibiotalar arthrodesis: in vitro analysis of 8 cadaver specimen in a dynamic model

Directory of Open Access Journals (Sweden)

Herberts T

2007-08-01

Full Text Available Abstract Background In the current discussion of surgical treatment of arthroses in the ankle joint, arthrodesis is in competition with artificial joint replacement. Up until now, no valid biomechanical findings have existed on the changes in intraarticular loads following arthrodesis. One argument against tibiotalar arthrodesis is the frequently associated, long-term degeneration of the talonavicular joint, which can be attributed to changes in biomechanical stresses. Methods We used a dynamic model to determine the changes in intraarticular forces and peak-pressure in the talonavicular joint and in the calcaneocuboid joint on 8 cadaver feet under stress in a simulated stance phase following tibiotalar arthrodesis. Results The change seen after arthrodesis was a tendency of relocation of average force and maximum pressure from the lateral onto the medial column of the foot. The average force increased from native 92 N to 100 N upon arthrodesis in the talonavicular joint and decreased in the calcaneocuboid joint from 54 N to 48 N. The peak pressure increased from native 3.9 MPa to 4.4 MPa in the talonavicular joint and in the calcaneocuboid joint from 3.3 MPa to 3.4 MPa. The increase of force and peak pressure on the talonavicular joint and decrease of force on the calcaneocuboid joint is statistically significant. Conclusion The increase in imparted force and peak pressure on the medial column of the foot following tibiotalar arthrodesis, as was demonstrated in a dynamic model, biomechanically explains the clinically observed phenomenon of cartilage degeneration on the medial dorsum of the foot in the long term. As a clinical conclusion from the measurements, it would be desirable to reduce the force imparted on the medial column with displacement onto the lateral forefoot, say by suitable shoe adjustment, in order to achieve a more favourable long-term clinical result.

Joint kinetic determinants of starting block performance in athletic sprinting.

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Brazil, Adam; Exell, Timothy; Wilson, Cassie; Willwacher, Steffen; Bezodis, Ian N; Irwin, Gareth

2018-07-01

The aim of this study was to explore the relationships between lower limb joint kinetics, external force production and starting block performance (normalised average horizontal power, NAHP). Seventeen male sprinters (100 m PB, 10.67 ± 0.32 s) performed maximal block starts from instrumented starting blocks (1000 Hz) whilst 3D kinematics (250 Hz) were also recorded during the block phase. Ankle, knee and hip resultant joint moment and power were calculated at the rear and front leg using inverse dynamics. Average horizontal force applied to the front (r = 0.46) and rear (r = 0.44) block explained 86% of the variance in NAHP. At the joint level, many "very likely" to "almost certain" relationships (r = 0.57 to 0.83) were found between joint kinetic data and the magnitude of horizontal force applied to each block although stepwise multiple regression revealed that 55% of the variance in NAHP was accounted for by rear ankle moment, front hip moment and front knee power. The current study provides novel insight into starting block performance and the relationships between lower limb joint kinetic and external kinetic data that can help inform physical and technical training practices for this skill.

Evaluation of Temporal Diagnostic Techniques for Two-Bunch Facet Beam

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Litos, M.D.; Bionta, M.R.; Dolgashev, V.A.; England, R.J.; Fritz, D.; Gilevich, S.; Hering, Ph.; Hogan, M.J.; /SLAC

2011-08-19

Three temporal diagnostic techniques are considered for use in the FACET facility at SLAC, which will incorporate a unique two-bunch beam for plasma wakefield acceleration experiments. The results of these experiments will depend strongly on the the inter-bunch spacing as well as the longitudinal profiles of the two bunches. A reliable, singleshot, high resolution measurement of the beam's temporal profile is necessary to fully quantify the physical mechanisms underlying the beam driven plasma wakefield acceleration. In this study we show that a transverse deflecting cavity is the diagnostic which best meets our criteria. Based on our laboratory testing, numerical calculations, and simulations of the three single-shot temporal diagnostic devices, the X-band TCAV system is the best candidate for resolving FACET's two-bunch beam, with an estimated resolution of 7 {micro}m. Both the S-band TCAV system and the EO system could resolve the peak-to-peak separation of the two bunches in the FACET beam with estimated resolutions of 25 {micro}m and 30 {micro}m, respectively, but would be unable to resolve the temporal profiles of the individual bunches themselves. Because the TCAV signal is more easily interpreted and because the reliability of the EO system is less well known, however, the S-band TCAV system would be the next preferred option after the X-band TCAV system. The Fesca-200 streak camera, though simple, compact, and reliable, is unable to achieve a resolution that would be of use to FACET.

Facets of clinicians' anxiety and the delivery of cognitive behavioral therapy.

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Levita, Liat; Salas Duhne, Paulina Gonzalez; Girling, Carla; Waller, Glenn

2016-02-01

Psychological therapists commonly fail to adhere to treatment protocols in everyday clinical practice. In part, this pattern of drift is attributable to anxious therapists being less likely to undertake some elements of evidence-based therapies - particularly the exposure-based elements. This study considers what facets of anxiety (cognitive, behavioral, physiological) are related to junior clinicians' reported use of cognitive-behavioral therapy techniques. Thirty-two clinicians (mean age = 28.9 years; mean length of CBT experience = 1.5 years; 23 female, nine male) who offered CBT were assessed for their cognitive, behavioral and physiological characteristics (Intolerance of Uncertainty scale; risk taking; skin conductance response and heart rate variability). While the three different facets of anxiety were relatively poorly associated with each other, as is usual in this literature, each facet was linked differently to the reported delivery of CBT techniques (P behavioral or cognitive methods. Of the three facets of anxiety, only physiological reactivity showed an association with the clinicians' temporal characteristics, with more experienced therapists being more likely to have greater skin conductance responses to positive and negative outcomes. These findings suggest that clinicians who are more anxious are less likely to deliver the full evidence-based form of CBT and to focus instead on less challenging elements of the therapy. Potential ways of overcoming this limitation are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stabilization of the sacroiliac joint.

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Shaffrey, Christopher I; Smith, Justin S

2013-07-01

Lower back pain and pain involving the area of the posterior iliac spine are extremely common. Degeneration of the sacroiliac joint (SIJ) is one potential cause for lower back pain and pain radiating into the groin or buttocks. Degenerative changes to the lumbar spine and sacroiliac joints are common. A recent study evaluating SIJ abnormalities in a primary low back pain population demonstrated 31.7% of patients demonstrated SI joint abnormalities. (4) As is the case for the evaluation and management of isolated lower back pain, the evaluation, management, and role for surgical intervention in SIJ pain is very controversial. Many patients have degenerative changes of the disc, facet joints, and SIJs. A recent systematic review performed to determine the diagnostic accuracy of tests available to clinicians to identify the disc, facet joint, or SIJ as the source of low back pain concluded that tests do exist that change the probability of the disc or SIJ (but not the facet joint) as the source of low back pain. (3) It was also concluded that the usefulness of these tests in clinical practice, particularly for guiding treatment selection, remains unclear. (3) Although there is general agreement that SIJ pathological changes are a potential cause of pain, there is far less agreement about the optimal management of these conditions. A variety of conditions can cause SIJ dysfunction including degenerative and inflammatory arthritis, trauma, prior lumbosacral fusion, hip arthritis, limb length inequality, infections, and neoplasia. (8) There is increasing evidence that image intensifier-guided single periarticular injection can correctly localize pain to the SIJ but the optimal management strategy remains controversial. Recent publications have compared surgical versus injection treatments and fusion versus denervation procedures. (1 , 8) A systematic review found improvement regardless of the treatment, with most studies reporting over 40% improvement in pain as measured

Modelling of the Human Knee Joint Supported by Active Orthosis

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Musalimov, V.; Monahov, Y.; Tamre, M.; Rõbak, D.; Sivitski, A.; Aryassov, G.; Penkov, I.

2018-02-01

The article discusses motion of a healthy knee joint in the sagittal plane and motion of an injured knee joint supported by an active orthosis. A kinematic scheme of a mechanism for the simulation of a knee joint motion is developed and motion of healthy and injured knee joints are modelled in Matlab. Angles between links, which simulate the femur and tibia are controlled by Simulink block of Model predictive control (MPC). The results of simulation have been compared with several samples of real motion of the human knee joint obtained from motion capture systems. On the basis of these analyses and also of the analysis of the forces in human lower limbs created at motion, an active smart orthosis is developed. The orthosis design was optimized to achieve an energy saving system with sufficient anatomy, necessary reliability, easy exploitation and low cost. With the orthosis it is possible to unload the knee joint, and also partially or fully compensate muscle forces required for the bending of the lower limb.

Modelling of the Human Knee Joint Supported by Active Orthosis

Directory of Open Access Journals (Sweden)

Musalimov V.

2018-02-01

Full Text Available The article discusses motion of a healthy knee joint in the sagittal plane and motion of an injured knee joint supported by an active orthosis. A kinematic scheme of a mechanism for the simulation of a knee joint motion is developed and motion of healthy and injured knee joints are modelled in Matlab. Angles between links, which simulate the femur and tibia are controlled by Simulink block of Model predictive control (MPC. The results of simulation have been compared with several samples of real motion of the human knee joint obtained from motion capture systems. On the basis of these analyses and also of the analysis of the forces in human lower limbs created at motion, an active smart orthosis is developed. The orthosis design was optimized to achieve an energy saving system with sufficient anatomy, necessary reliability, easy exploitation and low cost. With the orthosis it is possible to unload the knee joint, and also partially or fully compensate muscle forces required for the bending of the lower limb.

Mindfulness facets, trait emotional intelligence, emotional distress, and multiple health behaviors: A serial two-mediator model.

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Jacobs, Ingo; Wollny, Anna; Sim, Chu-Won; Horsch, Antje

2016-06-01

In the present study, we tested a serial mindfulness facets-trait emotional intelligence (TEI)-emotional distress-multiple health behaviors mediation model in a sample of N = 427 German-speaking occupational therapists. The mindfulness facets-TEI-emotional distress section of the mediation model revealed partial mediation for the mindfulness facets Act with awareness (Act/Aware) and Accept without judgment (Accept); inconsistent mediation was found for the Describe facet. The serial two-mediator model included three mediational pathways that may link each of the four mindfulness facets with multiple health behaviors. Eight out of 12 indirect effects reached significance and fully mediated the links between Act/Aware and Describe to multiple health behaviors; partial mediation was found for Accept. The mindfulness facet Observe was most relevant for multiple health behaviors, but its relation was not amenable to mediation. Implications of the findings will be discussed. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Specific adaptations of neuromuscular control and knee joint stiffness following sensorimotor training.

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Gruber, M; Bruhn, S; Gollhofer, A

2006-08-01

The aim of this study was to examine how fixations of the ankle joint during sensorimotor training (SMT) influence adaptations in mechanical stiffness and neuromuscular control of the knee joint. Sixty-three healthy subjects were randomly assigned to three training groups that differed in their degree of ankle joint fixation, which was either barefooted, with an ankle brace or with a ski boot. Mechanical knee joint stiffness and reflex control of m. vastus medialis, m. vastus lateralis, m. biceps femoris, and m. semitendinosus were tested during force controlled anterior tibial displacements. This force was applied as both a fast and a slow stimulus. After the training period the group that trained barefooted showed an increase in mechanical stiffness of the knee joint from 79 +/- 21 (Mean +/- SD) N/mm to 110 +/- 38 N/mm (p boots was able to improve knee joint stiffness from 67 +/- 26 N/mm to 96 +/- 47 N/mm (p knee joint injuries.

Experimental investigation on the failure of T-joints at elevated temperature under unaxial loading