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Sample records for adjacent-level spinal kinematics

  1. Effect of Device Rigidity and Physiological Loading on Spinal Kinematics after Dynamic Stabilization : An In-Vitro Biomechanical Study

    PubMed Central

    Chun, Kwonsoo; Yang, Inchul; Kim, Namhoon

    2015-01-01

    Objective To investigate the effects of posterior implant rigidity on spinal kinematics at adjacent levels by utilizing a cadaveric spine model with simulated physiological loading. Methods Five human lumbar spinal specimens (L3 to S1) were obtained and checked for abnormalities. The fresh specimens were stripped of muscle tissue, with care taken to preserve the spinal ligaments and facet joints. Pedicle screws were implanted in the L4 and L5 vertebrae of each specimen. Specimens were tested under 0 N and 400 N axial loading. Five different posterior rods of various elastic moduli (intact, rubber, low-density polyethylene, aluminum, and titanium) were tested. Segmental range of motion (ROM), center of rotation (COR) and intervertebral disc pressure were investigated. Results As the rigidity of the posterior rods increased, both the segmental ROM and disc pressure at L4-5 decreased, while those values increased at adjacent levels. Implant stiffness saturation was evident, as the ROM and disc pressure were only marginally increased beyond an implant stiffness of aluminum. Since the disc pressures of adjacent levels were increased by the axial loading, it was shown that the rigidity of the implants influenced the load sharing between the implant and the spinal column. The segmental CORs at the adjacent disc levels translated anteriorly and inferiorly as rigidity of the device increased. Conclusion These biomechanical findings indicate that the rigidity of the dynamic stabilization implant and physiological loading play significant roles on spinal kinematics at adjacent disc levels, and will aid in further device development. PMID:26713140

  2. Adjacent-Level Hypermobility and Instrumented-Level Fatigue Loosening With Titanium and PEEK Rods for a Pedicle Screw System: An In Vitro Study.

    PubMed

    Agarwal, Aakas; Ingels, Marcel; Kodigudla, Manoj; Momeni, Narjes; Goel, Vijay; Agarwal, Anand K

    2016-05-01

    Adjacent-level disease is a common iatrogenic complication seen among patients undergoing spinal fusion for low back pain. This is attributed to the postsurgical differences in stiffness between the spinal levels, which result in abnormal forces, stress shielding, and hypermobility at the adjacent levels. In addition, as most patients undergoing these surgeries are osteoporotic, screw loosening at the index level is a complication that commonly accompanies adjacent-level disease. Recent studies indicate that a rod with lower rigidity than that of titanium may help to overcome these detrimental effects at the adjacent level. The present study was conducted in vitro using 12 L1-S1 specimens divided into groups of six, with each group instrumented with either titanium rods or PEEK (polyetheretherketone) rods. The test protocol included subjecting intact specimens to pure moments of 10 Nm in extension and flexion using an FS20 Biomechanical Spine Test System (Applied Test Systems) followed by hybrid moments on the instrumented specimens to achieve the same L1-S1 motion as that of the intact specimens. During the protocol's later phase, the L4-L5 units from each specimen were segmented for cyclic loading followed by postfatigue kinematic analysis to highlight the differences in motion pre- and postfatigue. The objectives included the in vitro comparison of (1) the adjacent-level motion before and after instrumentation with PEEK and titanium rods and (2) the pre- and postfatigue motion at the instrumented level with PEEK and titanium rods. The results showed that the adjacent levels above the instrumentation caused increased flexion and extension with both PEEK and titanium rods. The postfatigue kinematic data showed that the motion at the instrumented level (L4-L5) increased significantly in both flexion and extension compared to prefatigue motion in titanium groups. However, there was no significant difference in motion between the pre- and postfatigue data in the PEEK

  3. Multisegment Kinematics of the Spinal Column: Soft Tissue Artifacts Assessment.

    PubMed

    Mahallati, Sara; Rouhani, Hossein; Preuss, Richard; Masani, Kei; Popovic, Milos R

    2016-07-01

    A major challenge in the assessment of intersegmental spinal column angles during trunk motion is the inherent error in recording the movement of bony anatomical landmarks caused by soft tissue artifacts (STAs). This study aims to perform an uncertainty analysis and estimate the typical errors induced by STA into the intersegmental angles of a multisegment spinal column model during trunk bending in different directions by modeling the relative displacement between skin-mounted markers and actual bony landmarks during trunk bending. First, we modeled the maximum displacement of markers relative to the bony landmarks with a multivariate Gaussian distribution. In order to estimate the distribution parameters, we measured these relative displacements on five subjects at maximum trunk bending posture. Then, in order to model the error depending on trunk bending angle, we assumed that the error grows linearly as a function of the bending angle. Second, we applied our error model to the trunk motion measurement of 11 subjects to estimate the corrected trajectories of the bony landmarks and investigate the errors induced into the intersegmental angles of a multisegment spinal column model. For this purpose, the trunk was modeled as a seven-segment rigid-body system described using 23 reflective markers placed on various bony landmarks of the spinal column. Eleven seated subjects performed trunk bending in five directions and the three-dimensional (3D) intersegmental angles during trunk bending were calculated before and after error correction. While STA minimally affected the intersegmental angles in the sagittal plane (<16%), it considerably corrupted the intersegmental angles in the coronal (error ranged from 59% to 551%) and transverse (up to 161%) planes. Therefore, we recommend using the proposed error suppression technique for STA-induced error compensation as a tool to achieve more accurate spinal column kinematics measurements. Particularly, for intersegmental

  4. Upper limb kinematics after cervical spinal cord injury: a review.

    PubMed

    Mateo, Sébastien; Roby-Brami, Agnès; Reilly, Karen T; Rossetti, Yves; Collet, Christian; Rode, Gilles

    2015-01-30

    Although a number of upper limb kinematic studies have been conducted, no review actually addresses the key-features of open-chain upper limb movements after cervical spinal cord injury (SCI). The aim of this literature review is to provide a clear understanding of motor control and kinematic changes during open-chain upper limb reaching, reach-to-grasp, overhead movements, and fast elbow flexion movements after tetraplegia. Using data from MEDLINE between 1966 and December 2014, we examined temporal and spatial kinematic measures and when available electromyographic recordings. We included fifteen control case and three series case studies with a total of 164 SCI participants and 131 healthy control participants. SCI participants efficiently performed a broad range of tasks with their upper limb and movements were planned and executed with strong kinematic invariants like movement endpoint accuracy and minimal cost. Our review revealed that elbow extension without triceps brachii relies on increased scapulothoracic and glenohumeral movements providing a dynamic coupling between shoulder and elbow. Furthermore, contrary to normal grasping patterns where grasping is prepared during the transport phase, reaching and grasping are performed successively after SCI. The prolonged transport phase ensures correct hand placement while the grasping relies on wrist extension eliciting either whole hand or lateral grip. One of the main kinematic characteristics observed after tetraplegia is motor slowing attested by increased movement time. This could be caused by (i) decreased strength, (ii) triceps brachii paralysis which disrupts normal agonist-antagonist co-contractions, (iii) accuracy preservation at movement endpoint, and/or (iv) grasping relying on tenodesis. Another feature is a reduction of maximal superior reaching during overhead movements which could be caused by i) strength deficit in agonist muscles like pectoralis major, ii) strength deficit in proximal synergic

  5. Upper limb kinematics after cervical spinal cord injury: a review.

    PubMed

    Mateo, Sébastien; Roby-Brami, Agnès; Reilly, Karen T; Rossetti, Yves; Collet, Christian; Rode, Gilles

    2015-01-01

    Although a number of upper limb kinematic studies have been conducted, no review actually addresses the key-features of open-chain upper limb movements after cervical spinal cord injury (SCI). The aim of this literature review is to provide a clear understanding of motor control and kinematic changes during open-chain upper limb reaching, reach-to-grasp, overhead movements, and fast elbow flexion movements after tetraplegia. Using data from MEDLINE between 1966 and December 2014, we examined temporal and spatial kinematic measures and when available electromyographic recordings. We included fifteen control case and three series case studies with a total of 164 SCI participants and 131 healthy control participants. SCI participants efficiently performed a broad range of tasks with their upper limb and movements were planned and executed with strong kinematic invariants like movement endpoint accuracy and minimal cost. Our review revealed that elbow extension without triceps brachii relies on increased scapulothoracic and glenohumeral movements providing a dynamic coupling between shoulder and elbow. Furthermore, contrary to normal grasping patterns where grasping is prepared during the transport phase, reaching and grasping are performed successively after SCI. The prolonged transport phase ensures correct hand placement while the grasping relies on wrist extension eliciting either whole hand or lateral grip. One of the main kinematic characteristics observed after tetraplegia is motor slowing attested by increased movement time. This could be caused by (i) decreased strength, (ii) triceps brachii paralysis which disrupts normal agonist-antagonist co-contractions, (iii) accuracy preservation at movement endpoint, and/or (iv) grasping relying on tenodesis. Another feature is a reduction of maximal superior reaching during overhead movements which could be caused by i) strength deficit in agonist muscles like pectoralis major, ii) strength deficit in proximal synergic

  6. Effects of dynamic office chairs on trunk kinematics, trunk extensor EMG and spinal shrinkage.

    PubMed

    van Dieën, J H; de Looze, M P; Hermans, V

    2001-06-10

    Seated work has been shown to constitute a risk factor for low-back pain. This is attributed to the prolonged and monotonous low-level mechanical load imposed by a seated posture. To evaluate the potential health effects with respect to the low back of office chairs with a movable seat and back rest, trunk kinematics, erector spinae EMG, spinal shrinkage and local discomfort were assessed in 10 subjects performing simulated office work. On three separate occasions subjects performed a 3 h task consisting of word processing, computer-aided design and reading. Three chairs were used, one with a fixed seat and back rest and two dynamic chairs, one with a seat and back rest movable in a fixed ratio with respect to each other, and one with a freely movable seat and back rest. Spinal shrinkage measurements showed a larger stature gain when working on the two dynamic chairs as compared with working on the chair with fixed seat and back rest. Trunk kinematics and erector spinae EMG were strongly affected by the task performed but not by the chair type. The results imply that dynamic office chairs offer a potential advantage over fixed chairs, but the effects of the task on the indicators of trunk load investigated were more pronounced than the effects of the chair.

  7. An investigation of the value of tridimensional kinematic analysis in functional diagnosis of lumbar spinal stenosis.

    PubMed

    Garbelotti, Silvio Antonio; Lucareli, Paulo Roberto Garcia; Ramalho, Amâncio; de Godoy, Wagner; Bernal, Milena; D'Andréa Greve, Julia Maria

    2014-01-01

    Diagnosis of lumbar spinal stenosis (LSS) is based on clinical examination and imaging. The aim of this study was to evaluate the influence of 3D gait analysis as a tool in the differential diagnosis of LSS. Fourteen patients participated in the study that consisted of three phases: (1) capture six gait cycles after rest, (2) walk on a treadmill for a maximum of 20 min, (3) capture six gait cycles after effort. From these data, the kinematic variables were compared with the perception of pain and the cross sectional area of the spinal canal as measured by magnetic resonance. Most of correlations were weak and showed that the most significant results are reported by the Gait Deviation Index (GDI). The Gait Deviation Index demonstrated moderate negative correlation with the perception of pain after effort was made by both limbs. This means that there is a significant decrease in the overall function of the lower limbs according to the increase in pain symptoms. This situation may be reflected in decreased cadence and speed beyond the times of single support for the left limb, and the balance of the right limb, as part of a strategy to protect against pain and imbalance. We found no correlation between gait and pain in the cross-sectional area of the spinal canal. Therefore, we believe that there is no advantage for the patient to make a 3-D gait analysis because the analysis does not add relevant information to clinical diagnosis.

  8. Quantitative analysis of hindlimbs locomotion kinematics in spinalized rats treated with Tamoxifen plus treadmill exercise.

    PubMed

    Osuna-Carrasco, L P; López-Ruiz, J R; Mendizabal-Ruiz, E G; De la Torre-Valdovinos, B; Bañuelos-Pineda, J; Jiménez-Estrada, I; Dueñas-Jiménez, S H

    2016-10-01

    Locomotion recovery after a spinal cord injury (SCI) includes axon regeneration, myelin preservation and increased plasticity in propriospinal and descending spinal circuitries. The combined effects of tamoxifen and exercise after a SCI were analyzed in this study to determine whether the combination of both treatments induces the best outcome in locomotion recovery. In this study, the penetrating injury was provoked by a sharp projectile that penetrates through right dorsal and ventral portions of the T13-L1 spinal segments, affecting propriospinal and descending/ascending tracts. Intraperitoneal application of Tamoxifen and a treadmill exercise protocol, as rehabilitation therapies, separately or combined, were used. To evaluate the functional recovery, angular patterns of the hip, knee and ankle joints as well as the leg pendulum-like movement (PLM) were measured during the unrestricted gait of treated and untreated (UT) animals, previously and after the traumatic injury (15 and 30days post-injury (dpi)). A pattern (curve) comparison analysis was made by using a locally designed Matlab script that determines the Frechet dissimilarity. The SCI magnitude was assessed by qualitative and quantitative histological analysis of the injury site 30days after SCI. Our results showed that all treated groups had an improvement in hindlimbs kinematics compared to the UT group, which showed a poor gait locomotion recovery throughout the rehabilitation period. The group with the combined treatment (tamoxifen+exercise (TE)) presented the best outcome. In conclusion, tamoxifen and treadmill exercise treatments are complementary therapies for the functional recovery of gait locomotion in hemi-spinalized rats. PMID:27450566

  9. Kinematics

    NASA Astrophysics Data System (ADS)

    Beggs, J. S.

    The notation, theory, and applications of kinematical concepts are explored in detail. Transformations are defined for coordinates, vector components, direction cosines, and the inertia matrix. Attitude is investigated in terms of characteristics of the direction cosine matrix, Euler's angles and angular placement theorem, and inertial navigation. Displacement and motion are considered, as are Euler's parameters as quaternions, and non-Cartesian coordinate systems. Applications of kinematics to gyro output transitions from one attitude to another, to linkage mechanisms, and to contacting surfaces are presented. Geometrical optics problems are examined, together with the dynamics of rigid bodies, coning, and the kinematics of steering a tractor and trailer.

  10. A novel spinal kinematic analysis using X-ray imaging and vicon motion analysis: a case study.

    PubMed

    Noh, Dong K; Lee, Nam G; You, Joshua H

    2014-01-01

    This study highlights a novel spinal kinematic analysis method and the feasibility of X-ray imaging measurements to accurately assess thoracic spine motion. The advanced X-ray Nash-Moe method and analysis were used to compute the segmental range of motion in thoracic vertebra pedicles in vivo. This Nash-Moe X-ray imaging method was compared with a standardized method using the Vicon 3-dimensional motion capture system. Linear regression analysis showed an excellent and significant correlation between the two methods (R2 = 0.99, p < 0.05), suggesting that the analysis of spinal segmental range of motion using X-ray imaging measurements was accurate and comparable to the conventional 3-dimensional motion analysis system. Clinically, this novel finding is compelling evidence demonstrating that measurements with X-ray imaging are useful to accurately decipher pathological spinal alignment and movement impairments in idiopathic scoliosis (IS).

  11. Adjacent level spondylodiscitis after anterior cervical decompression and fusion.

    PubMed

    Basu, Saumyajit; Sreeramalingam, Rathinavelu

    2012-05-01

    Postoperative spondylodiscitis after anterior cervical decompression and fusion (ACDF) is rare, but the same occurring at adjacent levels without disturbing the operated level is very rare. We report a case, with 5 year followup, who underwent ACDF from C5 to C7 for cervical spondylotic myelopathy. He showed neurological improvement after surgery but developed discharging sinus after 2 weeks, which healed with antibiotics. He improved on his preoperative symptoms well for the first 2 months. He started developing progressive neck pain and myelopathy after 3 months and investigations revealed spondylodiscitis at C3 and C4 with erosion, collapse, and kyphosis, without any evidence of implant failure or graft rejection at the operated level. He underwent reexploration and implant removal at the operated level (there was good fusion from C5 to C7) followed by debridement/decompression at C3, C4 along with iliac crest bone grafting and stabilization with plate and screws after maximum correction of kyphosis. The biopsy specimen grew Pseudomonas aeruginosa and appropriate sensitive antibiotics (gentamycin and ciprofloxacin) were given for 6 weeks. He was under regular followup for 5 years his myelopathy resolved completely and he is back to work. Complete decompression of the cord and fusion from C2 to C7 was demonstrable on postoperative imaging studies without any evidence of implant loosening or C1/C2 instability at the last followup. PMID:22719127

  12. Altered spinal kinematics and muscle recruitment pattern of the cervical and thoracic spine in people with chronic neck pain during functional task.

    PubMed

    Tsang, Sharon M H; Szeto, Grace P Y; Lee, Raymond Y W

    2014-02-01

    Knowledge on the spinal kinematics and muscle activation of the cervical and thoracic spine during functional task would add to our understanding of the performance and interplay of these spinal regions during dynamic condition. The purpose of this study was to examine the influence of chronic neck pain on the three-dimensional kinematics and muscle recruitment pattern of the cervical and thoracic spine during an overhead reaching task involving a light weight transfer by the upper limb. Synchronized measurements of the three-dimensional spinal kinematics and electromyographic activities of cervical and thoracic spine were acquired in thirty individuals with chronic neck pain and thirty age- and gender-matched asymptomatic controls. Neck pain group showed a significantly decreased cervical velocity and acceleration while performing the task. They also displayed with a predominantly prolonged coactivation of cervical and thoracic muscles throughout the task cycle. The current findings highlighted the importance to examine differential kinematic variables of the spine which are associated with changes in the muscle recruitment in people with chronic neck pain. The results also provide an insight to the appropriate clinical intervention to promote the recovery of the functional disability commonly reported in patients with neck pain disorders.

  13. Micro-Computed Tomography-Based Three-Dimensional Kinematic Analysis During Lateral Bending for Spinal Fusion Assessment in a Rat Posterolateral Lumbar Fusion Model

    PubMed Central

    Yamaguchi, Tomonori; Inoue, Nozomu; Sah, Robert L.; Lee, Yu-Po; Taborek, Alexander P.; Williams, Gregory M.; Moseley, Timothy A.; Bae, Won C.

    2014-01-01

    Rat posterolateral lumbar fusion (PLF) models have been used to assess the safety and effectiveness of new bone substitutes and osteoinductive growth factors using palpation, radiography, micro-computed tomography (μCT), and histology as standard methods to evaluate spinal fusion. Despite increased numbers of PLF studies involving alternative bone substitutes and growth factors, the quantitative assessment of treatment efficacy during spinal motion has been limited. The purpose of this study was to evaluate the effect of spinal fusion on lumbar spine segment stability during lateral bending using a μCT-based three-dimensional (3D) kinematic analysis in the rat PLF model. Fourteen athymic male rats underwent PLF surgery at L4/5 and received bone grafts harvested from the ilium and femurs of syngeneic rats (Isograft, n=7) or no graft (Sham, n=7). At 8 weeks after the PLF surgery, spinal fusion was assessed by manual palpation, plain radiography, μCT, and histology. To determine lumbar segmental motions at the operated level during lateral bending, 3D kinematic analysis was performed. The Isograft group, but not the Sham group, showed spinal fusion on manual palpation (6/7), solid fusion mass in radiographs (6/7), as well as bone bridging in μCT and histological images (5/7). Compared to the Sham group, the Isograft group revealed limited 3D lateral bending angular range of motion and lateral translation during lateral bending at the fused segment where disc height narrowing was observed. This μCT-based 3D kinematic analysis can provide a quantitative assessment of spinal fusion in a rat PLF model to complement current gold standard methods used for efficacy assessment of new therapeutic approaches. PMID:24199634

  14. Micro-computed tomography-based three-dimensional kinematic analysis during lateral bending for spinal fusion assessment in a rat posterolateral lumbar fusion model.

    PubMed

    Yamaguchi, Tomonori; Inoue, Nozomu; Sah, Robert L; Lee, Yu-Po; Taborek, Alexander P; Williams, Gregory M; Moseley, Timothy A; Bae, Won C; Masuda, Koichi

    2014-07-01

    Rat posterolateral lumbar fusion (PLF) models have been used to assess the safety and effectiveness of new bone substitutes and osteoinductive growth factors using palpation, radiography, micro-computed tomography (μCT), and histology as standard methods to evaluate spinal fusion. Despite increased numbers of PLF studies involving alternative bone substitutes and growth factors, the quantitative assessment of treatment efficacy during spinal motion has been limited. The purpose of this study was to evaluate the effect of spinal fusion on lumbar spine segment stability during lateral bending using a μCT-based three-dimensional (3D) kinematic analysis in the rat PLF model. Fourteen athymic male rats underwent PLF surgery at L4/5 and received bone grafts harvested from the ilium and femurs of syngeneic rats (Isograft, n=7) or no graft (Sham, n=7). At 8 weeks after the PLF surgery, spinal fusion was assessed by manual palpation, plain radiography, μCT, and histology. To determine lumbar segmental motions at the operated level during lateral bending, 3D kinematic analysis was performed. The Isograft group, but not the Sham group, showed spinal fusion on manual palpation (6/7), solid fusion mass in radiographs (6/7), as well as bone bridging in μCT and histological images (5/7). Compared to the Sham group, the Isograft group revealed limited 3D lateral bending angular range of motion and lateral translation during lateral bending at the fused segment where disc height narrowing was observed. This μCT-based 3D kinematic analysis can provide a quantitative assessment of spinal fusion in a rat PLF model to complement current gold standard methods used for efficacy assessment of new therapeutic approaches.

  15. Trunk active response and spinal forces in sudden forward loading: analysis of the role of perturbation load and pre-perturbation conditions by a kinematics-driven model.

    PubMed

    Shahvarpour, Ali; Shirazi-Adl, Aboulfazl; Larivière, Christian; Bazrgari, Babak

    2015-01-01

    Understanding the central nervous system (CNS) response strategy to trunk perturbations could help in prevention of back injuries and development of rehabilitation and treatment programs. This study aimed to investigate biomechanical response of the trunk musculoskeletal system under sudden forward loads, accounting for pre-perturbation conditions (preloading, initial posture and abdominal antagonistic coactivation) and perturbation magnitudes. Using a trunk kinematics-driven iterative finite element (FE) model, temporal profiles of measured kinematics and external load along with subjects' weights were prescribed to predict thoracolumbar muscle forces/latencies and spinal loads for twelve healthy subjects when tested in six conditions during pre- and post-perturbation periods. Results demonstrated that preloading the trunk significantly (i.e., p<0.05) increased pre-perturbation back muscle forces but significantly decreased post-perturbation peak muscle active forces and muscle latencies. Initial trunk flexion significantly increased muscle active and passive forces before the perturbation and their peak values after the perturbation, which in turn caused much larger spinal loads. Abdominal muscles antagonistic pre-activation did not alter the internal variables investigated in this study. Increase in sudden applied load increased muscle reflex activities and spinal forces; a 50 N increase in sudden load (i.e., when comparing 50 N to 100 N) increased the L5-S1 compression force by 1327 N under 5 N preload and by 1374 N under 50 N preload. Overall, forces on the spine and hence risk of failure substantially increased in sudden forward loading when the magnitude of sudden load increased and when the trunk was initially in a flexed posture. In contrast, a higher initial preload diminished reflex latencies and compression forces.

  16. Kinematic analysis of the gait of adult sheep during treadmill locomotion: Parameter values, allowable total error, and potential for use in evaluating spinal cord injury.

    PubMed

    Safayi, Sina; Jeffery, Nick D; Shivapour, Sara K; Zamanighomi, Mahdi; Zylstra, Tyler J; Bratsch-Prince, Joshua; Wilson, Saul; Reddy, Chandan G; Fredericks, Douglas C; Gillies, George T; Howard, Matthew A

    2015-11-15

    We are developing a novel intradural spinal cord (SC) stimulator designed to improve the treatment of intractable pain and the sequelae of SC injury. In-vivo ovine models of neuropathic pain and moderate SC injury are being implemented for pre-clinical evaluations of this device, to be carried out via gait analysis before and after induction of the relevant condition. We extend previous studies on other quadrupeds to extract the three-dimensional kinematics of the limbs over the gait cycle of sheep walking on a treadmill. Quantitative measures of thoracic and pelvic limb movements were obtained from 17 animals. We calculated the total-error values to define the analytical performance of our motion capture system for these kinematic variables. The post- vs. pre-injury time delay between contralateral thoracic and pelvic-limb steps for normal and SC-injured sheep increased by ~24s over 100 steps. The pelvic limb hoof velocity during swing phase decreased, while range of pelvic hoof elevation and distance between lateral pelvic hoof placements increased after SC injury. The kinematics measures in a single SC-injured sheep can be objectively defined as changed from the corresponding pre-injury values, implying utility of this method to assess new neuromodulation strategies for specific deficits exhibited by an individual.

  17. Kinematic analysis of the gait of adult sheep during treadmill locomotion: Parameter values, allowable total error, and potential for use in evaluating spinal cord injury.

    PubMed

    Safayi, Sina; Jeffery, Nick D; Shivapour, Sara K; Zamanighomi, Mahdi; Zylstra, Tyler J; Bratsch-Prince, Joshua; Wilson, Saul; Reddy, Chandan G; Fredericks, Douglas C; Gillies, George T; Howard, Matthew A

    2015-11-15

    We are developing a novel intradural spinal cord (SC) stimulator designed to improve the treatment of intractable pain and the sequelae of SC injury. In-vivo ovine models of neuropathic pain and moderate SC injury are being implemented for pre-clinical evaluations of this device, to be carried out via gait analysis before and after induction of the relevant condition. We extend previous studies on other quadrupeds to extract the three-dimensional kinematics of the limbs over the gait cycle of sheep walking on a treadmill. Quantitative measures of thoracic and pelvic limb movements were obtained from 17 animals. We calculated the total-error values to define the analytical performance of our motion capture system for these kinematic variables. The post- vs. pre-injury time delay between contralateral thoracic and pelvic-limb steps for normal and SC-injured sheep increased by ~24s over 100 steps. The pelvic limb hoof velocity during swing phase decreased, while range of pelvic hoof elevation and distance between lateral pelvic hoof placements increased after SC injury. The kinematics measures in a single SC-injured sheep can be objectively defined as changed from the corresponding pre-injury values, implying utility of this method to assess new neuromodulation strategies for specific deficits exhibited by an individual. PMID:26341152

  18. Cortical screw trajectory for instrumentation and fusion in the setting of osteopathic compression fracture allows for percutaneous kyphoplasty for adjacent level compression fractures.

    PubMed

    Pacione, Donato; Kim, Irene; Wilson, Taylor A; Frempong-Boadu, Anthony

    2015-05-01

    Spinal fixation in the osteoporotic patient can be challenging due to the poor trabecular bone quality of the vertebral body. Patients with osteoporotic vertebral body compression fractures are at risk for future compression fractures at adjacent levels, especially after cement augmentation. The purpose of this technical report is to describe the utilization of a cortical screw trajectory along with kyphoplasty for a patient with an osteoporotic compression fracture as well as degenerative spinal disease. This trajectory allows for the possibility of percutaneous pedicle access in the event of future compression fractures. Our patient underwent a decompressive laminectomy and kyphoplasty at the level of an osteoporotic compression fracture. The fracture was stabilized with cortical screw instrumentation and fusion at a level above and a level below the fracture. Subsequently the patient developed an adjacent level fracture within the fusion construct. Due to the utilization of a cortical screw trajectory for the initial fusion, the traditional pedicle trajectory was still accessible. As a result, the new fracture was treated with a percutaneous kyphoplasty through a standard pedicle trajectory. In conclusion, the use of a cortical screw trajectory for stabilization of osteoporotic compression fractures provides for a stronger bone screw interface and avoids osteoporotic trabecular vertebral body bone. At the same time this trajectory allows for future percutaneous pedicular access in the event that the patient suffers future compression fractures.

  19. Upper extremity kinematics and kinetics during the performance of a stationary wheelie in manual wheelchair users with a spinal cord injury.

    PubMed

    Lalumiere, Mathieu; Gagnon, Dany H; Routhier, François; Bouyer, Laurent; Desroches, Guillaume

    2014-08-01

    No comprehensive biomechanical study has documented upper extremity (U/E) kinematics and kinetics during the performance of wheelchair wheelies among manual wheelchair users (MWUs). The aim of this study was to describe movement strategies (kinematics), mechanical loads (kinetics), and power at the nondominant U/E joints during a wheelie among MWUs with spinal cord injury (SCI). During a laboratory assessment, 16 MWUs with SCI completed four wheelie trials on a rigid surface. Each participant's wheelchair was equipped with instrumented wheels to record handrim kinetics, while U/E and wheelchair kinematics were recorded with a 3D motion analysis system. The greatest mean and peak total net joint moments were generated by the shoulder flexors (mean = 7.2 ± 3.5 N·m; peak = 20.7 ± 12.9 N·m) and internal rotators (mean = 3.8 ± 2.2 N·m; peak = 11.4 ± 10.9 N·m) as well as by the elbow flexors (mean = 5.5 ± 2.5 N·m; peak = 14.1 ± 7.6 N·m) during the performance of wheelies. Shoulder flexor and internal rotator efforts predominantly generate the effort needed to lift the front wheels of the wheelchair, whereas the elbow flexor muscles control these shoulder efforts to reach a state of balance. In combination with a task-specific training program that remains essential to properly learn how to control wheelies among MWUs with SCI, rehabilitation professionals should also propose a shoulder flexor, internal rotator, and elbow flexor strengthening program.

  20. Stress Reduction in Adjacent Level Discs via Dynamic Instrumentation: A Finite Element Analysis

    PubMed Central

    Castellvi, Antonio E.; Huang, Hao; Vestgaarden, Tov; Saigal, Sunil; Pienkowski, David

    2007-01-01

    Background Conventional (rigid) fusion instrumentation is believed to accelerate the degeneration of adjacent discs by increasing stresses caused by motion discontinuity. Fusion instrumentation that employs reduced rod stiffness and increased axial motion, or dynamic instrumentation, may partially alleviate this problem, but the effects of this instrumentation on the stresses in the adjacent disc are unknown. We used a finiteelement model to calculate and compare the stresses in the adjacent-level disc that are induced by rigid and dynamic posterior lumbar fusion instrumentation. Methods A 3-dimensional finite-element model of the lumbar spine was obtained that simulated flexion and extension. The L5–S1 segment of this model was fused, and the L4–L5 segment was fixed with rigid or dynamic instrumentation. The mechanical properties of the dynamic instrumentation were determined by laboratory testing and then used in the finite-element model. Peak stresses in the lumbar discs were calculated and compared. Results The reduced-stiffness component of the dynamic instrumentation was associated with a 1% to 2% reduction in peak compressive stresses in the adjacent-level disc (at 45° flexion), and the increased axial motion component of this instrumentation reduced peak disc stress by 8% to 9%. Areas of disc tissue exposed to 80% of peak stresses of 6.17 MPa were 47% less for discs adjacent to dynamic instrumentation than for those adjacent to rigid instrumentation. Conclusions Reduced stiffness and increased axial motion of dynamic posterior lumbar fusion instrumentation designs result in an approximately 10% cumulative stress reduction for each flexion cycle. The effect of this stress reduction over many cycles may be substantial. Clinical Relevance The cumulative effect of this reduced amplitude and distribution of peak stresses in the adjacent disc may partially alleviate the problem of adjacent-level disc degeneration. PMID:25802582

  1. Trunk and Shoulder Kinematic and Kinetic and Electromyographic Adaptations to Slope Increase during Motorized Treadmill Propulsion among Manual Wheelchair Users with a Spinal Cord Injury

    PubMed Central

    Champagne, Audrey

    2015-01-01

    The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments. PMID:25793200

  2. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    PubMed

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population.

  3. Trunk and shoulder kinematic and kinetic and electromyographic adaptations to slope increase during motorized treadmill propulsion among manual wheelchair users with a spinal cord injury.

    PubMed

    Gagnon, Dany; Babineau, Annie-Claude; Champagne, Audrey; Desroches, Guillaume; Aissaoui, Rachid

    2015-01-01

    The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments. PMID:25793200

  4. Cascading Adjacent Level Vertebral Compression Fractures Necessitating a Series of Eleven Kyphoplasties.

    PubMed

    Curatolo, Evan; Reuter, Matthew; Samad, Adil; Flynn, Daniel; Menkowitz, Marc; Paragioudakis, Steve

    2015-01-01

    Vertebral kyphoplasty is a procedure used for the treatment of compression fractures. While early randomized-controlled trials were equivocal regarding its benefits, more recent RCTs have shown favorable results for kyphoplasty with regard to pain relief, functional recovery, and health-care related quality of life compared to control patients. Risks of kyphoplasty include but are not limited to cement extrusion, infection, hematoma, and vertebral body fracture of adjacent levels. We describe a case of a 66-year-old male attorney who underwent eleven kyphoplasties in an approximately one-year period, the majority of which were for fractures of vertebrae adjacent to those previously treated with kyphoplasty. Information on treatment was gathered from the patient's hospital chart and outpatient office notes. Following the last of the eleven kyphoplasties (two at T8, one each at all vertebrae from T9 to L5), the patient was able to function without pain and return to work. His physiologic thoracic kyphosis of 40 degrees prior to the first procedure was maintained, as were his lung and abdominal volumes. We conclude that kyphoplasty is an appropriate procedure for the treatment of vertebral compression fractures and can be used repeatedly to address fractures of levels adjacent to a previous kyphoplasty. PMID:26509091

  5. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level

    PubMed Central

    Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  6. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level.

    PubMed

    Hakan, Tayfun; Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  7. Spinal tumor

    MedlinePlus

    Tumor - spinal cord ... spinal tumors occur in the nerves of the spinal cord itself. Most often these are ependymomas and other ... gene mutations. Spinal tumors can occur: Inside the spinal cord (intramedullary) In the membranes (meninges) covering the spinal ...

  8. Spinal fusion

    MedlinePlus

    ... Anterior spinal fusion; Spine surgery - spinal fusion; Low back pain - fusion; Herniated disk - fusion ... If you had chronic back pain before surgery, you will likely still have some pain afterward. Spinal fusion is unlikely to take away all your pain ...

  9. Spinal injury

    MedlinePlus

    ... head. Alternative Names Spinal cord injury; SCI Images Skeletal spine Vertebra, cervical (neck) Vertebra, lumbar (low back) Vertebra, thoracic (mid back) Vertebral column Central nervous system Spinal cord injury Spinal anatomy Two person roll - ...

  10. Effect of locomotor training in completely spinalized cats previously submitted to a spinal hemisection.

    PubMed

    Martinez, Marina; Delivet-Mongrain, Hugo; Leblond, Hugues; Rossignol, Serge

    2012-08-01

    After a spinal hemisection in cats, locomotor plasticity occurring at the spinal level can be revealed by performing, several weeks later, a complete spinalization below the first hemisection. Using this paradigm, we recently demonstrated that the hemisection induces durable changes in the symmetry of locomotor kinematics that persist after spinalization. Can this asymmetry be changed again in the spinal state by interventions such as treadmill locomotor training started within a few days after the spinalization? We performed, in 9 adult cats, a spinal hemisection at thoracic level 10 and then a complete spinalization at T13, 3 weeks later. Cats were not treadmill trained during the hemispinal period. After spinalization, 5 of 9 cats were not trained and served as control while 4 of 9 cats were trained on the treadmill for 20 min, 5 d a week for 3 weeks. Using detailed kinematic analyses, we showed that, without training, the asymmetrical state of locomotion induced by the hemisection was retained durably after the subsequent spinalization. By contrast, training cats after spinalization induced a reversal of the left/right asymmetries, suggesting that new plastic changes occurred within the spinal cord through locomotor training. Moreover, training was shown to improve the kinematic parameters and the performance of the hindlimb on the previously hemisected side. These results indicate that spinal locomotor circuits, previously modified by past experience such as required for adaptation to the hemisection, can remarkably respond to subsequent locomotor training and improve bilateral locomotor kinematics, clearly showing the benefits of locomotor training in the spinal state.

  11. Retraining the injured spinal cord

    NASA Technical Reports Server (NTRS)

    Edgerton, V. R.; Leon, R. D.; Harkema, S. J.; Hodgson, J. A.; London, N.; Reinkensmeyer, D. J.; Roy, R. R.; Talmadge, R. J.; Tillakaratne, N. J.; Timoszyk, W.; Tobin, A.

    2001-01-01

    The present review presents a series of concepts that may be useful in developing rehabilitative strategies to enhance recovery of posture and locomotion following spinal cord injury. First, the loss of supraspinal input results in a marked change in the functional efficacy of the remaining synapses and neurons of intraspinal and peripheral afferent (dorsal root ganglion) origin. Second, following a complete transection the lumbrosacral spinal cord can recover greater levels of motor performance if it has been exposed to the afferent and intraspinal activation patterns that are associated with standing and stepping. Third, the spinal cord can more readily reacquire the ability to stand and step following spinal cord transection with repetitive exposure to standing and stepping. Fourth, robotic assistive devices can be used to guide the kinematics of the limbs and thus expose the spinal cord to the new normal activity patterns associated with a particular motor task following spinal cord injury. In addition, such robotic assistive devices can provide immediate quantification of the limb kinematics. Fifth, the behavioural and physiological effects of spinal cord transection are reflected in adaptations in most, if not all, neurotransmitter systems in the lumbosacral spinal cord. Evidence is presented that both the GABAergic and glycinergic inhibitory systems are up-regulated following complete spinal cord transection and that step training results in some aspects of these transmitter systems being down-regulated towards control levels. These concepts and observations demonstrate that (a) the spinal cord can interpret complex afferent information and generate the appropriate motor task; and (b) motor ability can be defined to a large degree by training.

  12. Spinal brucellosis.

    PubMed

    Tali, E Turgut; Koc, A Murat; Oner, A Yusuf

    2015-05-01

    Spinal involvement in human brucellosis is a common condition and a significant cause of morbidity and mortality, particularly in endemic areas, because it is often associated with therapeutic failure. Most chronic brucellosis cases are the result of inadequate treatment of the initial episode. Recognition of spinal brucellosis is challenging. Early diagnosis is important to ensure proper treatment and decrease morbidity and mortality. Radiologic evaluation has gained importance in diagnosis and treatment planning, including interventional procedures and monitoring of all spinal infections.

  13. Spinal deformity.

    PubMed

    Bunnell, W P

    1986-12-01

    Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis. PMID:3786010

  14. Spinal Osteosarcoma

    PubMed Central

    Katonis, P.; Datsis, G.; Karantanas, A.; Kampouroglou, A.; Lianoudakis, S.; Licoudis, S.; Papoutsopoulou, E.; Alpantaki, K.

    2013-01-01

    Although osteosarcoma represents the second most common primary bone tumor, spinal involvement is rare, accounting for 3%–5% of all osteosarcomas. The most frequent symptom of osteosarcoma is pain, which appears in almost all patients, whereas more than 70% exhibit neurologic deficit. At a molecular level, it is a tumor of great genetic complexity and several genetic disorders have been associated with its appearance. Early diagnosis and careful surgical staging are the most important factors in accomplishing sufficient management. Even though overall prognosis remains poor, en-block tumor removal combined with adjuvant radiotherapy and chemotherapy is currently the treatment of choice. This paper outlines histopathological classification, epidemiology, diagnostic procedures, and current concepts of management of spinal osteosarcoma. PMID:24179411

  15. Spinal Bracing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Dr. Arthur Copes of the Copes Foundation, Baton Rouge, LA, says that 35 percent of the 50 technical reports he received from the NASA/Southern University Industrial Applications Center in Baton Rouge and the Central Industrial Applications Center, Durant, OK, were vital to the development of his Copes Scoliosis Braces, which are custom designed and feature a novel pneumatic bladder that exerts constant corrective pressure to the torso to slowly reduce or eliminate the spinal curve.

  16. Global and segmental kinematic changes following sequential resection of posterior osteoligamentous structures in the lumbar spine: An in vitro biomechanical investigation using pure moment testing protocols.

    PubMed

    Chamoli, Uphar; Korkusuz, Mert H; Sabnis, Ashutosh B; Manolescu, Andrei R; Tsafnat, Naomi; Diwan, Ashish D

    2015-11-01

    Lumbar spinal surgeries may compromise the integrity of posterior osteoligamentous structures implicating mechanical stability. Circumstances necessitating a concomitant surgery to achieve restabilisation are not well understood. The main objective of this in vitro study was to quantify global and segmental (index and adjacent levels) kinematic changes in the lumbar spine following sequential resection of the posterior osteoligamentous structures using pure moment testing protocols. Six fresh frozen cadaveric kangaroo lumbar spines (T12-S1) were tested under a bending moment in flexion-extension, bilateral bending, and axial torsion in a 6-degree-of-freedom Kinematic Spine Simulator. Specimens were tested in the following order: intact state (D0), after interspinous and supraspinous ligaments transection between L4 and L5 (D1), further after a total bilateral facetectomy between L4 and L5 (D2). Segmental motions at the cephalad, damaged, and caudal levels were recorded using an infrared-based motion tracking device. Following D1, no significant change in the global range of motion was observed in any of the bending planes. Following D2, a significant increase in the global range of motion from the baseline (D0) was observed in axial torsion (median normalised change +20%). At the damaged level, D2 resulted in a significant increase in the segmental range of motion in flexion-extension (+77%) and axial torsion (+492%). Additionally, a significant decrease in the segmental range of motion in axial torsion (-35%) was observed at the caudal level following D2. These results suggest that a multi-segment lumbar spine acts as a mechanism for transmitting motions, and that a compromised joint may significantly alter motion transfer to adjacent segments. We conclude that the interspinous and supraspinous ligaments play a modest role in restricting global spinal motions within physiologic limits. Following interspinous and supraspinous ligaments transection, a total

  17. Tethered Spinal Cord Syndrome

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS NINDS Tethered Spinal Cord Syndrome Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What is Tethered Spinal Cord Syndrome? Tethered spinal cord syndrome is a neurological ...

  18. Spinal Cord Infarction

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Spinal Cord Infarction Information Page Table of Contents (click to ... Organizations Related NINDS Publications and Information What is Spinal Cord Infarction? Spinal cord infarction is a stroke either ...

  19. Spinal injury - resources

    MedlinePlus

    Resources - spinal injury ... The following organizations are good resources for information on spinal injury : National Institute of Neurological Disorders and Stroke -- www.ninds.nih.gov The National Spinal Cord Injury ...

  20. Spinal Cord Injury Map

    MedlinePlus

    ... on the severity of the injury. Tap this spinal column to see how the level of injury affects loss of function and control. Learn more about spinal cord injuries. A spinal cord injury affects the ...

  1. Spinal dysraphism.

    PubMed

    Sgouros, Spyros

    2013-09-01

    In the last decade there have been significant improvements in all the fields of management of patients with spinal dysraphism, which have increased dramatically the quality of life of these children. Prevention of spina bifida with food fortification is becoming increasingly practiced worldwide. As result, in many parts of the world the frequency of myelomeningocele has decreased. Intrauterine closure of myelomeningocele has been attempted in many institutions with variable results. While it is still at the sphere of experimental therapy, it is reasonable to anticipate progress in this field in the next decade. Antenatal MR imaging is already providing very high level of detail even before the child is born. This creates new ethical dilemmas and requires additional care, but has improved significantly the overall management of patients and their families. Further improvements are anticipated in this field. Management of neuropathic bladder has improved significantly in the last decade and is anticipated to play an increasing role in the long term follow up. Surgery for spinal cord tethering in all its forms has improved in the last decade, with far more chances of complete untethering now in comparison to 10-15 years ago, with the use of micro-neurosurgical techniques and intraoperative monitoring. It is reasonable to expect that in the next decade, intraoperative neurophysiological monitoring during spinal cord surgery will become mandatory. In the 2013 Annual Special Issue we have assembled a team of authors distinguished in their fields, who bring us up to date with all the latest developments. PMID:24013314

  2. Effects of load on good morning kinematics and EMG activity.

    PubMed

    Vigotsky, Andrew David; Harper, Erin Nicole; Ryan, David Russell; Contreras, Bret

    2015-01-01

    Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises. PMID:25653899

  3. Effects of load on good morning kinematics and EMG activity.

    PubMed

    Vigotsky, Andrew David; Harper, Erin Nicole; Ryan, David Russell; Contreras, Bret

    2015-01-01

    Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  4. Effects of load on good morning kinematics and EMG activity

    PubMed Central

    Harper, Erin Nicole; Ryan, David Russell; Contreras, Bret

    2015-01-01

    Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises. PMID:25653899

  5. Spinal surgery -- cervical - series (image)

    MedlinePlus

    The cervical spinal column is made up of vertebral bodies which protect the spinal cord. ... spinal nerves, trauma, and narrowing (stenosis) of the spinal column around the spinal cord. Symptoms of cervical spine ...

  6. Augmented kinematic feedback system

    NASA Astrophysics Data System (ADS)

    Andert, Ed P., Jr.; Archipley-Smith, Donna K.

    1994-07-01

    This paper discusses a real-time augmented kinematic feedback system which can be used as a diagnosis tool for individuals with motor disabilities. The system captures and analyzes movement via color targets attached to an individual and then feeds back information about movement kinematics. This target tracking approach has a high potential for achieving a real- time kinematic assessment capability. The approach recognizes distinct moving colored targets using video data. Multiple colored targets are attached to an individual at strategic locations and then target movement is tracked using a video data acquisition system. The ability to track and assess movement in real-time allows researchers and practitioners to better study and potentially treat various motor disabilities. Recent research has suggested that kinematic feedback can enhance motor recovery of disabled individuals. This approach addresses the need for a real-time measure of human movement and discusses using kinematic feedback to enhance disability recovery.

  7. Spinal instrumentation.

    PubMed

    Spivak, J M; Balderston, R A

    1994-03-01

    The past decade has seen a dramatic increase in the availability of spinal instrumentation devices, enabling surgeons to treat a variety of spinal disorders with improved results and lower morbidity. In each anatomic region new fixation systems exist. Improvement in fusion rates with supplemental plate fixation following anterior cervical diskectomies and reconstructions has been demonstrated; these devices can now be applied more safely than ever before. Posterior occipitocervical plating to the C-2 pedicle and C3-6 lateral masses can provide stable fixation despite incompetent posterior arch bony structures. Newer, more rigid anterior thoracolumbar instrumentation allows for correction of thoracolumbar and lumbar scoliosis along fewer levels and with better maintenance of lordosis and is also useful following anterior decompression for tumor and trauma. Segmental hook fixation of the posterior thoracolumbar spine has allowed for improved correction of deformity without increased morbidity or the need for postoperative bracing in many cases. Finally, the use of transpedicular screw fixation of the lumbosacral spine allows for excellent segmental fixation without intact posterior elements, including facet joints, and has significantly improved the fusion rate in lumbosacral fusions. PMID:8024965

  8. Three tooth kinematic coupling

    SciTech Connect

    Hale, L.C.

    2000-05-23

    A three tooth kinematic coupling is disclosed based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  9. Three tooth kinematic coupling

    SciTech Connect

    Hale, Layton C.

    2000-01-01

    A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  10. Spinal cord trauma

    MedlinePlus

    ... if the bones or disks have been weakened Fragments of bone (such as from broken vertebrae, which are the ... presses on the spinal cord (decompression laminectomy ) Remove bone fragments, disk fragments, or foreign objects Fuse broken spinal ...

  11. Brain and Spinal Tumors

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Brain and Spinal Tumors Information Page Synonym(s): Spinal Cord ... en Español Additional resources from MedlinePlus What are Brain and Spinal Tumors? Tumors of the brain and ...

  12. Spinal Cord Diseases

    MedlinePlus

    ... damages the vertebrae or other parts of the spine, this can also injure the spinal cord. Other spinal cord problems include Tumors Infections such as meningitis and polio Inflammatory diseases Autoimmune diseases Degenerative diseases such as amyotrophic lateral sclerosis and spinal ...

  13. Spinal Cord Injuries

    MedlinePlus

    ... your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures or ... bone disks that make up your spine. Most injuries don't cut through your spinal cord. Instead, ...

  14. Management of Spinal Meningiomas.

    PubMed

    Ravindra, Vijay M; Schmidt, Meic H

    2016-04-01

    Spinal meningiomas are the most common spinal tumors encountered in adults, and account for 6.5% of all craniospinal tumors. The treatment for these lesions is primarily surgical, but emerging modalities may include chemotherapy and radiosurgery. In this article, the current management of spinal meningiomas and the body of literature surrounding conventional treatment is reviewed and discussed.

  15. Kinematics of Tape Recording.

    ERIC Educational Resources Information Center

    Coleman, J. J.

    1982-01-01

    Describes mathematics of the nonliner relationships between a constant-speed, capstan-driven magnetic tape transport mechanism and a constant-angular-velocity take-up reel. The relationship, derived from the sum of a partial, serves in recognition of a finite tape. Thickness can serve as an example of rotational kinematics. (Author/SK)

  16. Kinematically redundant robot manipulators

    NASA Technical Reports Server (NTRS)

    Baillieul, J.; Hollerbach, J.; Brockett, R.; Martin, D.; Percy, R.; Thomas, R.

    1987-01-01

    Research on control, design and programming of kinematically redundant robot manipulators (KRRM) is discussed. These are devices in which there are more joint space degrees of freedom than are required to achieve every position and orientation of the end-effector necessary for a given task in a given workspace. The technological developments described here deal with: kinematic programming techniques for automatically generating joint-space trajectories to execute prescribed tasks; control of redundant manipulators to optimize dynamic criteria (e.g., applications of forces and moments at the end-effector that optimally distribute the loading of actuators); and design of KRRMs to optimize functionality in congested work environments or to achieve other goals unattainable with non-redundant manipulators. Kinematic programming techniques are discussed, which show that some pseudo-inverse techniques that have been proposed for redundant manipulator control fail to achieve the goals of avoiding kinematic singularities and also generating closed joint-space paths corresponding to close paths of the end effector in the workspace. The extended Jacobian is proposed as an alternative to pseudo-inverse techniques.

  17. Spinal pain.

    PubMed

    Izzo, R; Popolizio, T; D'Aprile, P; Muto, M

    2015-05-01

    The spinal pain, and expecially the low back pain (LBP), represents the second cause for a medical consultation in primary care setting and a leading cause of disability worldwide [1]. LBP is more often idiopathic. It has as most frequent cause the internal disc disruption (IDD) and is referred to as discogenic pain. IDD refers to annular fissures, disc collapse and mechanical failure, with no significant modification of external disc shape, with or without endplates changes. IDD is described as a separate clinical entity in respect to disc herniation, segmental instability and degenerative disc desease (DDD). The radicular pain has as most frequent causes a disc herniation and a canal stenosis. Both discogenic and radicular pain also have either a mechanical and an inflammatory genesis. For to be richly innervated, facet joints can be a direct source of pain, while for their degenerative changes cause compression of nerve roots in lateral recesses and in the neural foramina. Degenerative instability is a common and often misdiagnosed cause of axial and radicular pain, being also a frequent indication for surgery. Acute pain tends to extinguish along with its cause, but the setting of complex processes of peripheral and central sensitization may influence its evolution in chronic pain, much more difficult to treat. The clinical assessment of pain source can be a challenge because of the complex anatomy and function of the spine; the advanced imaging methods are often not sufficient for a definitive diagnosis because similar findings could be present in either asymptomatic and symptomatic subjects: a clinical correlation is always mandatory and the therapy cannot rely uniquely upon any imaging abnormalities. Purpose of this review is to address the current concepts on the pathophysiology of discogenic, radicular, facet and dysfunctional pain, focusing on the role of the imaging in the diagnostic setting, to potentially address a correct approach also to minimally

  18. Spinal cord contusion models.

    PubMed

    Young, Wise

    2002-01-01

    Most human spinal cord injuries involve contusions of the spinal cord. Many investigators have long used weight-drop contusion animal models to study the pathophysiology and genetic responses of spinal cord injury. All spinal cord injury therapies tested to date in clinical trial were validated in such models. In recent years, the trend has been towards use of rats for spinal cord injury studies. The MASCIS Impactor is a well-standardized rat spinal cord contusion model that produces very consistent graded spinal cord damage that linearly predicts 24-h lesion volumes, 6-week white matter sparing, and locomotor recovery in rats. All aspects of the model, including anesthesia for male and female rats, age rather than body weight criteria, and arterial blood gases were empirically selected to enhance the consistency of injury. PMID:12440371

  19. Augmentation of Voluntary Locomotor Activity by Transcutaneous Spinal Cord Stimulation in Motor-Incomplete Spinal Cord-Injured Individuals.

    PubMed

    Hofstoetter, Ursula S; Krenn, Matthias; Danner, Simon M; Hofer, Christian; Kern, Helmut; McKay, William B; Mayr, Winfried; Minassian, Karen

    2015-10-01

    The level of sustainable excitability within lumbar spinal cord circuitries is one of the factors determining the functional outcome of locomotor therapy after motor-incomplete spinal cord injury. Here, we present initial data using noninvasive transcutaneous lumbar spinal cord stimulation (tSCS) to modulate this central state of excitability during voluntary treadmill stepping in three motor-incomplete spinal cord-injured individuals. Stimulation was applied at 30 Hz with an intensity that generated tingling sensations in the lower limb dermatomes, yet without producing muscle reflex activity. This stimulation changed muscle activation, gait kinematics, and the amount of manual assistance required from the therapists to maintain stepping with some interindividual differences. The effect on motor outputs during treadmill-stepping was essentially augmentative and step-phase dependent despite the invariant tonic stimulation. The most consistent modification was found in the gait kinematics, with the hip flexion during swing increased by 11.3° ± 5.6° across all subjects. This preliminary work suggests that tSCS provides for a background increase in activation of the lumbar spinal locomotor circuitry that has partially lost its descending drive. Voluntary inputs and step-related feedback build upon the stimulation-induced increased state of excitability in the generation of locomotor activity. Thus, tSCS essentially works as an electrical neuroprosthesis augmenting remaining motor control.

  20. Occupant Kinematics in Laboratory Rollover Tests: ATD Response and Biofidelity.

    PubMed

    Zhang, Qi; Lessley, David L; Riley, Patrick; Toczyski, Jacek; Lockerby, Jack; Foltz, Patrick; Overby, Brian; Seppi, Jeremy; Crandall, Jeff R; Kerrigan, Jason R

    2014-11-01

    Rollover crashes are a serious public health problem in United States, with one third of traffic fatalities occurring in crashes where rollover occurred. While it has been shown that occupant kinematics affect the injury risk in rollover crashes, no anthropomorphic test device (ATD) has yet demonstrated kinematic biofidelity in rollover crashes. Therefore, the primary goal of this study was to assess the kinematic response biofidelity of six ATDs (Hybrid III, Hybrid III Pedestrian, Hybrid III with Pedestrian Pelvis, WorldSID, Polar II and THOR) by comparing them to post mortem human surrogate (PMHS) kinematic response targets published concurrently; and the secondary goal was to evaluate and compare the kinematic response differences among these ATDs. Trajectories (head, T1, T4, T10, L1 and sacrum), spinal segment (head-to-T1, T1-to-T4, T4-T10, T10-L1, and L1-to-sacrum) rotations relative to the rollover buck, and spinal segment extension/compression were calculated from the collected kinematics data from an optical motion tracking system. Response differences among the ATDs were observed mainly due to the different lateral bending stiffness of the spine from their varied architecture, while the additional thoracic joint in Polar II and THOR did not seem to provide more flexion/extension compliance than the other ATDs. In addition, the ATD response data were compared to PMHS response corridors developed from similar tests for assessing ATD biofidelity. All of the ATDs, generally, drifted outboard and upward during the tests similar to the PMHS. However, accompanied with this upward and outward motion, the ATD head and upper torso pitched forward (~10 degrees) while the PMHS' head and upper torso pitching rearward (~10 to ~15 degrees), due to the absence of flexion/extension compliance in the ATD spine. The differences in these pitch motions resulted in a difference of 130 mm to 160 mm in the longitudinal position of the head at 195 degrees of roll angle. Finally

  1. Occupant Kinematics in Laboratory Rollover Tests: ATD Response and Biofidelity.

    PubMed

    Zhang, Qi; Lessley, David L; Riley, Patrick; Toczyski, Jacek; Lockerby, Jack; Foltz, Patrick; Overby, Brian; Seppi, Jeremy; Crandall, Jeff R; Kerrigan, Jason R

    2014-11-01

    Rollover crashes are a serious public health problem in United States, with one third of traffic fatalities occurring in crashes where rollover occurred. While it has been shown that occupant kinematics affect the injury risk in rollover crashes, no anthropomorphic test device (ATD) has yet demonstrated kinematic biofidelity in rollover crashes. Therefore, the primary goal of this study was to assess the kinematic response biofidelity of six ATDs (Hybrid III, Hybrid III Pedestrian, Hybrid III with Pedestrian Pelvis, WorldSID, Polar II and THOR) by comparing them to post mortem human surrogate (PMHS) kinematic response targets published concurrently; and the secondary goal was to evaluate and compare the kinematic response differences among these ATDs. Trajectories (head, T1, T4, T10, L1 and sacrum), spinal segment (head-to-T1, T1-to-T4, T4-T10, T10-L1, and L1-to-sacrum) rotations relative to the rollover buck, and spinal segment extension/compression were calculated from the collected kinematics data from an optical motion tracking system. Response differences among the ATDs were observed mainly due to the different lateral bending stiffness of the spine from their varied architecture, while the additional thoracic joint in Polar II and THOR did not seem to provide more flexion/extension compliance than the other ATDs. In addition, the ATD response data were compared to PMHS response corridors developed from similar tests for assessing ATD biofidelity. All of the ATDs, generally, drifted outboard and upward during the tests similar to the PMHS. However, accompanied with this upward and outward motion, the ATD head and upper torso pitched forward (~10 degrees) while the PMHS' head and upper torso pitching rearward (~10 to ~15 degrees), due to the absence of flexion/extension compliance in the ATD spine. The differences in these pitch motions resulted in a difference of 130 mm to 160 mm in the longitudinal position of the head at 195 degrees of roll angle. Finally

  2. Trunk response analysis under sudden forward perturbations using a kinematics-driven model.

    PubMed

    Bazrgari, B; Shirazi-Adl, A; Larivière, C

    2009-06-19

    Accurate quantification of the trunk transient response to sudden loading is crucial in prevention, evaluation, rehabilitation and training programs. An iterative dynamic kinematics-driven approach was used to evaluate the temporal variation of trunk muscle forces, internal loads and stability under sudden application of an anterior horizontal load. The input kinematics is hypothesized to embed basic dynamic characteristics of the system that can be decoded by our kinematics-driven approach. The model employs temporal variation of applied load, trunk forward displacement and surface EMG of select muscles measured on two healthy and one chronic low-back pain subjects to a sudden load. A finite element model accounting for measured kinematics, nonlinear passive properties of spine, detailed trunk musculature with wrapping of global extensor muscles, gravity load and trunk biodynamic characteristics is used to estimate the response under measured sudden load. Results demonstrate a delay of approximately 200ms in extensor muscle activation in response to sudden loading. Net moment and spinal loads substantially increase as muscles are recruited to control the trunk under sudden load. As a result and due also to the trunk flexion, system stability significantly improves. The reliability of the kinematics-driven approach in estimating the trunk response while decoding measured kinematics is demonstrated. Estimated large spinal loads highlight the risk of injury that likely further increases under larger perturbations, muscle fatigue and longer delays in activation.

  3. The "beneficial" effects of locomotor training after various types of spinal lesions in cats and rats.

    PubMed

    Rossignol, Serge; Martinez, Marina; Escalona, Manuel; Kundu, Aritra; Delivet-Mongrain, Hugo; Alluin, Olivier; Gossard, Jean-Pierre

    2015-01-01

    This chapter reviews a number of experiments on the recovery of locomotion after various types of spinal lesions and locomotor training mainly in cats. We first recall the major evidence on the recovery of hindlimb locomotion in completely spinalized cats at the T13 level and the role played by the spinal locomotor network, also known as the central pattern generator, as well as the beneficial effects of locomotor training on this recovery. Having established that hindlimb locomotion can recover, we raise the issue as to whether spinal plastic changes could also contribute to the recovery after partial spinal lesions such as unilateral hemisections. We found that after such hemisection at T10, cats could recover quadrupedal locomotion and that deficits could be improved by training. We further showed that, after a complete spinalization a few segments below the first hemisection (at T13, i.e., the level of previous studies on spinalization), cats could readily walk with the hindlimbs within hours of completely severing the remaining spinal tracts and not days as is usually the case with only a single complete spinalization. This suggests that neuroplastic changes occurred below the first hemisection so that the cat was already primed to walk after the spinalization subsequent to the hemispinalization 3 weeks before. Of interest is the fact that some characteristic kinematic features in trained or untrained hemispinalized cats could remain after complete spinalization, suggesting that spinal changes induced by training could also be durable. Other studies on reflexes and on the pattern of "fictive" locomotion recorded after curarization corroborate this view. More recent work deals with training cats in more demanding situations such as ladder treadmill (vs. flat treadmill) to evaluate how the locomotor training regimen can influence the spinal cord. Finally, we report our recent studies in rats using compressive lesions or surgical complete spinalization and find

  4. Parallel Kinematic Machines (PKM)

    SciTech Connect

    Henry, R.S.

    2000-03-17

    The purpose of this 3-year cooperative research project was to develop a parallel kinematic machining (PKM) capability for complex parts that normally require expensive multiple setups on conventional orthogonal machine tools. This non-conventional, non-orthogonal machining approach is based on a 6-axis positioning system commonly referred to as a hexapod. Sandia National Laboratories/New Mexico (SNL/NM) was the lead site responsible for a multitude of projects that defined the machining parameters and detailed the metrology of the hexapod. The role of the Kansas City Plant (KCP) in this project was limited to evaluating the application of this unique technology to production applications.

  5. Kinematics of Strong Discontinuities

    NASA Technical Reports Server (NTRS)

    Peterson, K.; Nguyen, G.; Sulsky, D.

    2006-01-01

    Synthetic Aperture Radar (SAR) provides a detailed view of the Arctic ice cover. When processed with the RADARSAT Geophysical Processor System (RGPS), it provides estimates of sea ice motion and deformation over large regions of the Arctic for extended periods of time. The deformation is dominated by the appearance of linear kinematic features that have been associated with the presence of leads. The RGPS deformation products are based on the assumption that the displacement and velocity are smooth functions of the spatial coordinates. However, if the dominant deformation of multiyear ice results from the opening, closing and shearing of leads, then the displacement and velocity can be discontinuous. This presentation discusses the kinematics associated with strong discontinuities that describe possible jumps in displacement or velocity. Ice motion from SAR data are analyzed using this framework. It is assumed that RGPS cells deform due to the presence of a lead. The lead orientation is calculated to optimally account for the observed deformation. It is shown that almost all observed deformation can be represented by lead opening and shearing. The procedure used to reprocess motion data to account for leads will be described and applied to regions of the Beaufort Sea. The procedure not only provides a new view of ice deformation, it can be used to obtain information about the presence of leads for initialization and/or validation of numerical simulations.

  6. Spinal subarachnoid haematoma after spinal anaesthesia: case report.

    PubMed

    Vidal, Marion; Strzelecki, Antoine; Houadec, Mireille; Krikken, Isabelle Ranz; Danielli, Antoine; Souza Neto, Edmundo Pereira de

    2016-01-01

    Subarachnoid haematoma after spinal anaesthesia is known to be very rare. In the majority of these cases, spinal anaesthesia was difficult to perform and/or unsuccessful; other risk factors included antiplatelet or anticoagulation therapy, and direct spinal cord trauma. We report a case of subarachnoid haematoma after spinal anaesthesia in a young patient without risk factors. PMID:27591468

  7. Integration of sensory, spinal, and volitional descending inputs in regulation of human locomotion.

    PubMed

    Gerasimenko, Yury; Gad, Parag; Sayenko, Dimitry; McKinney, Zach; Gorodnichev, Ruslan; Puhov, Aleksandr; Moshonkina, Tatiana; Savochin, Aleksandr; Selionov, Victor; Shigueva, Tatiana; Tomilovskaya, Elena; Kozlovskaya, Inessa; Edgerton, V Reggie

    2016-07-01

    We reported previously that both transcutaneous electrical spinal cord stimulation and direct pressure stimulation of the plantar surfaces of the feet can elicit rhythmic involuntary step-like movements in noninjured subjects with their legs in a gravity-neutral apparatus. The present experiments investigated the convergence of spinal and plantar pressure stimulation and voluntary effort in the activation of locomotor movements in uninjured subjects under full body weight support in a vertical position. For all conditions, leg movements were analyzed using electromyographic (EMG) recordings and optical motion capture of joint kinematics. Spinal cord stimulation elicited rhythmic hip and knee flexion movements accompanied by EMG bursting activity in the hamstrings of 6/6 subjects. Similarly, plantar stimulation induced bursting EMG activity in the ankle flexor and extensor muscles in 5/6 subjects. Moreover, the combination of spinal and plantar stimulation exhibited a synergistic effect in all six subjects, eliciting greater motor responses than either modality alone. While the motor responses to spinal vs. plantar stimulation seems to activate distinct but overlapping spinal neural networks, when engaged simultaneously, the stepping responses were functionally complementary. As observed during induced (involuntary) stepping, the most significant modulation of voluntary stepping occurred in response to the combination of spinal and plantar stimulation. In light of the known automaticity and plasticity of spinal networks in absence of supraspinal input, these findings support the hypothesis that spinal and plantar stimulation may be effective tools for enhancing the recovery of motor control in individuals with neurological injuries and disorders. PMID:27075538

  8. Kinematically Detected Halo Streams

    NASA Astrophysics Data System (ADS)

    Smith, Martin C.

    Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over-densities in velocity-space, which can remain coherent for much longer than spatial over-densities. This chapter reviews a number of studies that have hunted for these accretion relics, both in the nearby solar-neighborhood and the more-distant stellar halo. Many observational surveys have driven this field forwards, from early work with the Hipparcos mission, to contemporary surveys like RAVE and SDSS. This active field continues to flourish, providing many new discoveries, and will be revolutionized as the Gaia mission delivers precise proper motions for a billion stars in our Galaxy.

  9. O-star kinematics

    SciTech Connect

    Karimova, D.K.; Pavlovskaya, E.D.

    1984-01-01

    Proper motions determined by the authors are utilized to study the kinematics of 79 O-type stars at distance r< or =2.5 kpc. The sample is divided into two groups, having space-velocity dispersions tau/sub I/roughly-equal10 km/sec, sigma/sub II/roughly-equal35 km/sec. Solutions for the velocity-field parameters for group I yield a galactic angular rotation speed ..omega../sub 0/ = 24.9 km sec/sup -1/ kpc/sup -1/ at the sun (for R/sub 0/ = 10.0 kpc) and an Oort constant A = 12.2 km sec/sup -1/ kpc/sup -1/. Most of the O stars exhibit a small z-velocity directed away from the galactic plane. The velocity-ellipsoid parameters and box-orbit elements are calculated.

  10. Rattlesnake strike behavior: kinematics

    PubMed

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

  11. Occupant Kinematics in Laboratory Rollover Tests: PMHS Response.

    PubMed

    Lessley, David J; Riley, Patrick; Zhang, Qi; Foltz, Patrick; Overby, Brian; Heltzel, Sara; Sochor, Mark; Crandall, Jeff; Kerrigan, Jason R

    2014-11-01

    The objective of the current study was to characterize the whole-body kinematic response of restrained PMHS in controlled laboratory rollover tests. A dynamic rollover test system (DRoTS) and a parametric vehicle buck were used to conduct 36 rollover tests on four adult male PMHS with varied test conditions to study occupant kinematics during the rollover event. The DRoTS was used to drop/catch and rotate the test buck, which replicated the occupant compartment of a typical mid-sized SUV, around its center of gravity without roof-to-ground contact. The studied test conditions included a quasi-static inversion (4 tests), an inverted drop and catch that produced a 3 g vertical deceleration (4 tests), a pure dynamic roll at 360 degrees/second (11 tests), and a roll with a superimposed drop and catch produced vertical deceleration (17 tests). Each PMHS was restrained with a three-point belt and was tested in both leading-side and trailing-side front-row seating positions. Whole-body kinematics were measured using a 3D motion capture system that quantified occupant displacement relative to the vehicle buck for the X-axis (longitudinal), Y-axis (lateral), and Z-axis (vertical) directions. Additionally the spine was divided into five segments to describe intrasegmental kinematics of the spine, including segment rotations as well as spinal extension and compression. The reported data represent the most complete set of kinematic response targets for a restrained occupant in a variety of dynamic rollover conditions, and are immediately useful for efforts to evaluate and improve existing ATDs and computational models for use in the rollover crash environment.

  12. Occupant Kinematics in Laboratory Rollover Tests: PMHS Response.

    PubMed

    Lessley, David J; Riley, Patrick; Zhang, Qi; Foltz, Patrick; Overby, Brian; Heltzel, Sara; Sochor, Mark; Crandall, Jeff; Kerrigan, Jason R

    2014-11-01

    The objective of the current study was to characterize the whole-body kinematic response of restrained PMHS in controlled laboratory rollover tests. A dynamic rollover test system (DRoTS) and a parametric vehicle buck were used to conduct 36 rollover tests on four adult male PMHS with varied test conditions to study occupant kinematics during the rollover event. The DRoTS was used to drop/catch and rotate the test buck, which replicated the occupant compartment of a typical mid-sized SUV, around its center of gravity without roof-to-ground contact. The studied test conditions included a quasi-static inversion (4 tests), an inverted drop and catch that produced a 3 g vertical deceleration (4 tests), a pure dynamic roll at 360 degrees/second (11 tests), and a roll with a superimposed drop and catch produced vertical deceleration (17 tests). Each PMHS was restrained with a three-point belt and was tested in both leading-side and trailing-side front-row seating positions. Whole-body kinematics were measured using a 3D motion capture system that quantified occupant displacement relative to the vehicle buck for the X-axis (longitudinal), Y-axis (lateral), and Z-axis (vertical) directions. Additionally the spine was divided into five segments to describe intrasegmental kinematics of the spine, including segment rotations as well as spinal extension and compression. The reported data represent the most complete set of kinematic response targets for a restrained occupant in a variety of dynamic rollover conditions, and are immediately useful for efforts to evaluate and improve existing ATDs and computational models for use in the rollover crash environment. PMID:26192958

  13. Irradiation of Spinal Metastases: Should We Continue to Include One Uninvolved Vertebral Body Above and Below in the Radiation Field?

    SciTech Connect

    Klish, Darren S.; Grossman, Patricia; Allen, Pamela K.; Rhines, Laurence D.; Chang, Eric L.

    2011-12-01

    Purpose: Historically, the appropriate target volume to be irradiated for spinal metastases is 1-2 vertebral bodies above and below the level of involvement for three reasons: (1) to avoid missing the correct level in the absence of simulation or (2) to account for the possibility of spread of disease to the adjacent level, and (3) to account for beam penumbra. In this study, we hypothesized that isolated failures occurring in the level adjacent to level treated with stereotactic body radiosurgery (SBRS) were infrequent and that with improved localization techniques with image-guided radiation therapy, treatment of only the involved level of spinal metastases may be more appropriate. Methods and Materials: Patients who had received SBRS treatments to only the involved level of the spine as part of a prospective trial for spinal metastases comprised the study population. Follow-up imaging with spine MRI was performed at 3-month intervals following initial treatment. Failures in the adjacent (V{+-}1, V{+-}2) and distant spine were identified and classified accordingly. Results: Fifty-eight patients met inclusion criteria for this study and harbored 65 distinct spinal metastases. At 18-month median follow-up, seven (10.7%) patients failed simultaneously at adjacent levels V{+-}1 and at multiple sites throughout the spine. Only two (3%) patients experienced isolated, solitary adjacent failures at 9 and 11 months, respectively. Conclusion: Isolated local failures of the unirradiated adjacent vertebral bodies may occur in <5% of patients with isolated spinal metastasis. On the basis of the data, the current practice of irradiating one vertebral body above and below seems unnecessary and could be revised to irradiate only the involved level(s) of the spine metastasis.

  14. Spinal and epidural anesthesia

    MedlinePlus

    Intraspinal anesthesia; Subarachnoid anesthesia; Epidural; Peridural anesthesia ... Spinal and epidural anesthesia have fewer side effects and risks than general anesthesia (asleep and pain-free). Patients usually recover their senses ...

  15. Spinal Muscular Atrophy

    MedlinePlus

    ... diseases that progressively destroy lower motor neurons—nerve cells in the brain stem and spinal cord that control essential voluntary muscle activity such as speaking, walking, breathing, and swallowing. ...

  16. Spinal Cord Injury 101

    MedlinePlus

    ... is "Braingate" research? What is the status of stem-cell research? How would stem-cell therapies work in the treatment of spinal cord injuries? What does stem-cell research on animals tell us? When can we expect ...

  17. Spinal Cord Injury

    MedlinePlus

    ... Dramatically Improves Function After Spinal Cord Injury in Rats May 2004 press release on an experimental treatment ... NINDS). Signaling Molecule Improves Nerve Cell Regeneration in Rats August 2002 news summary on a signaling molecule ...

  18. What Is Spinal Stenosis?

    MedlinePlus

    ... To order the Sports Injuries Handout on Health full-text version, please contact NIAMS using the contact information ... publication. To order the Spinal Stenosis Q&A full-text version, please contact NIAMS using the contact information ...

  19. Spinal cord abscess

    MedlinePlus

    ... irritation (inflammation) and the collection of infected material (pus) in or around the spinal cord. ... occurs as a complication of an epidural abscess . Pus forms as a collection of: Destroyed tissue cells ...

  20. [Meningitis after spinal anesthesia].

    PubMed

    Mouchrif, Issam; Berdaii, Adnane; Labib, Ismail; Harrandou, Moustapha

    2016-01-01

    Meningitis is a rare but serious complication of epidural and spinal anesthesia. Bacterial meningitis is mainly caused by Gram-positive cocci, implying an exogenous contamination which suggests a lack of asepsis. The evolution is usually favorable after treatment, but at the expense of increased health care costs and, sometimes, of significant neurological sequelae. We report a case of bacterial meningitis after spinal anesthesia for caesarean section. PMID:27642477

  1. Modeling spinal cord biomechanics

    NASA Astrophysics Data System (ADS)

    Luna, Carlos; Shah, Sameer; Cohen, Avis; Aranda-Espinoza, Helim

    2012-02-01

    Regeneration after spinal cord injury is a serious health issue and there is no treatment for ailing patients. To understand regeneration of the spinal cord we used a system where regeneration occurs naturally, such as the lamprey. In this work, we analyzed the stress response of the spinal cord to tensile loading and obtained the mechanical properties of the cord both in vitro and in vivo. Physiological measurements showed that the spinal cord is pre-stressed to a strain of 10%, and during sinusoidal swimming, there is a local strain of 5% concentrated evenly at the mid-body and caudal sections. We found that the mechanical properties are homogeneous along the body and independent of the meninges. The mechanical behavior of the spinal cord can be characterized by a non-linear viscoelastic model, described by a modulus of 20 KPa for strains up to 15% and a modulus of 0.5 MPa for strains above 15%, in agreement with experimental data. However, this model does not offer a full understanding of the behavior of the spinal cord fibers. Using polymer physics we developed a model that relates the stress response as a function of the number of fibers.

  2. Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

    PubMed

    Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

    2016-06-14

    Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates.

  3. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  4. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  5. Tensor networks from kinematic space

    DOE PAGESBeta

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-20

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry,more » obtaining a detailed agreement which includes the entwinement sector. In conclusion, we discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.« less

  6. Tensor networks from kinematic space

    NASA Astrophysics Data System (ADS)

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  7. Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

    PubMed Central

    Choi, Jisoo; Kim, Sohee

    2016-01-01

    Objective To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. Methods A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. Results The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. Conclusion The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study. PMID:26962413

  8. Gait in adolescent idiopathic scoliosis: kinematics and electromyographic analysis.

    PubMed

    Mahaudens, P; Banse, X; Mousny, M; Detrembleur, C

    2009-04-01

    Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. Consequently, AIS can modify human locomotion. Very few studies have investigated a simple activity like walking in a cohort of well-defined untreated patients with scoliosis. The first goal of this study is to evaluate the effects of scoliosis and scoliosis severity on kinematic and electromyographic (EMG) gait variables compared to an able-bodied population. The second goal is to look for any asymmetry in these parameters during walking. Thirteen healthy girls and 41 females with untreated AIS, with left thoracolumbar or lumbar primary structural curves were assessed. AIS patients were divided into three clinical subgroups (group 1 < 20 degrees, group 2 between 20 and 40 degrees, and group 3 > 40 degrees). Gait analysis included synchronous bilateral kinematic and EMG measurements. The subjects walked on a treadmill at 4 km/h (comfortable speed). The tridimensional (3D) shoulder, pelvis, and lower limb motions were measured using 22 reflective markers tracked by four infrared cameras. The EMG timing activity was measured using bipolar surface electrodes on quadratus lumborum, erector spinae, gluteus medius, rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius muscles. Statistical comparisons (ANOVA) were performed across groups and sides for kinematic and EMG parameters. The step length was reduced in AIS compared to normal subjects (7% less). Frontal shoulder, pelvis, and hip motion and transversal hip motion were reduced in scoliosis patients (respectively, 21, 27, 28, and 22% less). The EMG recording during walking showed that the quadratus lumborum, erector spinae, gluteus medius, and semitendinosus muscles contracted during a longer part of the stride in scoliotic patients (46% of the stride) compared with normal subjects (35% of the stride). There was no significant difference between scoliosis groups 1

  9. Aero-optimum hovering kinematics.

    PubMed

    Nabawy, Mostafa R A; Crowther, William J

    2015-08-07

    Hovering flight for flapping wing vehicles requires rapid and relatively complex reciprocating movement of a wing relative to a stationary surrounding fluid. This note develops a compact analytical aero-kinematic model that can be used for optimization of flapping wing kinematics against aerodynamic criteria of effectiveness (maximum lift) and efficiency (minimum power for a given amount of lift). It can also be used to make predictions of required flapping frequency for a given geometry and basic aerodynamic parameters. The kinematic treatment is based on a consolidation of an existing formulation that allows explicit derivation of flapping velocity for complex motions whereas the aerodynamic model is based on existing quasi-steady analysis. The combined aero-kinematic model provides novel explicit analytical expressions for both lift and power of a hovering wing in a compact form that enables exploration of a rich kinematic design space. Good agreement is found between model predictions of flapping frequency and observed results for a number of insects and optimal hovering kinematics identified using the model are consistent with results from studies using higher order computational models. For efficient flight, the flapping angle should vary using a triangular profile in time leading to a constant velocity flapping motion, whereas for maximum effectiveness the shape of variation should be sinusoidal. For both cases the wing pitching motion should be rectangular such that pitch change at stroke reversal is as rapid as possible.

  10. Aero-optimum hovering kinematics.

    PubMed

    Nabawy, Mostafa R A; Crowther, William J

    2015-08-01

    Hovering flight for flapping wing vehicles requires rapid and relatively complex reciprocating movement of a wing relative to a stationary surrounding fluid. This note develops a compact analytical aero-kinematic model that can be used for optimization of flapping wing kinematics against aerodynamic criteria of effectiveness (maximum lift) and efficiency (minimum power for a given amount of lift). It can also be used to make predictions of required flapping frequency for a given geometry and basic aerodynamic parameters. The kinematic treatment is based on a consolidation of an existing formulation that allows explicit derivation of flapping velocity for complex motions whereas the aerodynamic model is based on existing quasi-steady analysis. The combined aero-kinematic model provides novel explicit analytical expressions for both lift and power of a hovering wing in a compact form that enables exploration of a rich kinematic design space. Good agreement is found between model predictions of flapping frequency and observed results for a number of insects and optimal hovering kinematics identified using the model are consistent with results from studies using higher order computational models. For efficient flight, the flapping angle should vary using a triangular profile in time leading to a constant velocity flapping motion, whereas for maximum effectiveness the shape of variation should be sinusoidal. For both cases the wing pitching motion should be rectangular such that pitch change at stroke reversal is as rapid as possible. PMID:26248884

  11. Pediatric spinal trauma.

    PubMed

    Huisman, Thierry A G M; Wagner, Matthias W; Bosemani, Thangamadhan; Tekes, Aylin; Poretti, Andrea

    2015-01-01

    Pediatric spinal trauma is unique. The developing pediatric spinal column and spinal cord deal with direct impact and indirect acceleration/deceleration or shear forces very different compared to adult patients. In addition children are exposed to different kind of traumas. Moreover, each age group has its unique patterns of injury. Familiarity with the normal developing spinal anatomy and kind of traumas is essential to correctly diagnose injury. Various imaging modalities can be used. Ultrasound is limited to the neonatal time period; plain radiography and computer tomography are typically used in the acute work-up and give highly detailed information about the osseous lesions. Magnetic resonance imaging is more sensitive for disco-ligamentous and spinal cord injuries. Depending on the clinical presentation and timing of trauma the various imaging modalities will be employed. In the current review article, a summary of the epidemiology and distribution of posttraumatic lesions is discussed in the context of the normal anatomical variations due to progressing development of the child. PMID:25512255

  12. Speed and spinal injuries.

    PubMed

    Healy, D G; Connolly, P; Stephens, M M; O'Byrne, J M; McManus, F; McCormack, D

    2004-09-01

    Road traffic accidents (RTA) are a significant cause of spinal trauma. On the 31st of October 2002 a new penalty system for speed related driving offences was introduced in Ireland. Our intention was to assess the effects of the introduction of this system on the activity of the National Spinal Injuries Centre (NSIC) with a retrospective review of all admissions from November 1998 until October 2003. The number of new acute admissions to the spinal injury unit during the study period was 831. In the first 6 months of the new system the number of RTA related admissions fell significantly to 17 compared to an average of 33 in the preceding 4 years. However, this effect was not maintained in the second 6 months. The fall in spinal injuries following RTA in the first 6 months of the new system parallels the pattern of road death reduction in this period. This suggests that driving behaviour can be modified with direct benefits in reducing spinal injuries. However, this effect has not persisted in the second 6 months of the new system suggesting that to maintain this change the perception and familiarity of a penalty are important factors in its impact.

  13. Learning Spinal Manipulation

    PubMed Central

    Harvey, Marie-Pierre; Wynd, Shari; Richardson, Lance; Dugas, Claude; Descarreaux, Martin

    2011-01-01

    Purpose: The goal of the present study was to quantify the high-velocity, low-amplitude spinal manipulation biomechanical parameters in two cohorts of students from different teaching institutions. The first cohort of students was taught chiropractic techniques in a patient–doctor positioning practice setting, while the second cohort of students was taught in a “complete practice” manipulation setting, thus performing spinal manipulation skills on fellow student colleagues. It was hypothesized that the students exposed to complete practice would perform the standardized spinal manipulation with better biomechanical parameters. Methods: Participants (n = 88) were students enrolled in two distinct chiropractic programs. Thoracic spine manipulation skills were assessed using an instrumented manikin, which allowed the measurement of applied force. Dependent variables included peak force, time to peak force, rate of force production, peak force variability, and global coordination. Results: The results revealed that students exposed to complete practice demonstrated lower time to peak force values, higher peak force, and a steeper rate of force production compared with students in the patient–doctor positioning scenario. A significant group by gender interaction was also noted for the time to peak force and rate of force production variables. Conclusion: The results of the present study confirm the importance of chiropractic technique curriculum and perhaps gender in spinal manipulation skill learning. It also stresses the importance of integrating spinal manipulation skills practice early in training to maximize the number and the quality of significant learner–instructor interactions. PMID:22069337

  14. Spinal injury in a U.S. Army light observation helicopter.

    PubMed

    Shanahan, D F; Mastroianni, G R

    1984-01-01

    All accident reports involving U.S. Army OH-58 series helicopters were analyzed to determine vertical and horizontal velocity change at impact and the relationship of this kinematic data to the production of spinal injury. This analysis determined that spinal injury is related primarily to vertical velocity change at impact and is relatively independent of horizontal velocity change. The dramatic increase in the rate of spinal injury occurring just above the design sink speed of the aircraft landing gear (3.7 m/s) suggests that the fuselage and seat provide little additional impact attenuation capability above that of the gear alone. It is concluded that if this aircraft were modified to provide protection to the occupants for impacts up to 9.1 m/s (30 ft/s), approximately 80% of all spinal injury incurred in survivable accidents could be substantially mitigated. The incorporation of energy absorbing seats is recommended. PMID:6696693

  15. [Lumbar spinal angiolipoma].

    PubMed

    Isla, Alberto; Ortega Martinez, Rodrigo; Pérez López, Carlos; Gómez de la Riva, Alvaro; Mansilla, Beatriz

    2016-01-01

    Spinal angiolipomas are fairly infrequent benign tumours that are usually located in the epidural space of the thoracic column and represent 0.14% to 1.3% of all spinal tumours. Lumbar angiolipomas are extremely rare, representing only 9.6% of all spinal extradural angiolipomas. We report the case of a woman who complained of a lumbar pain of several months duration with no neurological focality and that had intensified in the last three days without her having had any injury or made a physical effort. The MR revealed an extradural mass L1-L2, on the posterior face of the medulla, decreasing the anteroposterior diameter of the canal. The patient symptoms improved after surgery. Total extirpation of the lesion is possible in most cases, and the prognosis is excellent even if the lesion is infiltrative. For this reason, excessively aggressive surgery is not necessary to obtain complete resection. PMID:27263067

  16. Spinal injuries in children.

    PubMed

    Babcock, J L

    1975-05-01

    Spinal injuries with neurologic sequelae are a rare but catastrophic injury. Many of these injuries might be preventable through proper parent and child education, particularly in water sports and vehicles accidents. A significant number of neurologic injuries are incomplete at the time of injury and proper rescue and initial care may make the difference between life as a quadriplegic and life as a normal individual. Because of the complexity of the management of the child with spinal injuries and their relative rarity, the definitive care is best undertaken at hospitals which specialize in the care of spinal injuries. Progressive deformity of the spine, a problem unique to childhood and adolescent paralysis, is often preventable with prolonged immobilization and protection of the spine. Progressive deformities which interfere with function or result in neurologic deterioration require an aggressive surgical approach. PMID:1124228

  17. Spinal Subdural Haematoma

    PubMed Central

    Manish K, Kothari; Chandrakant, Shah Kunal; Abhay M, Nene

    2015-01-01

    Introduction: Spinal Subdural hematoma is a rare cause of radiculopathy and spinal cord compression syndromes. It’s early diagnosis is essential. Chronological appearance of these bleeds vary on MRI. Case Report: A 56 year old man presented with progressive left lower limb radiculopathy and paraesthesias with claudication of three days duration. MRI revealed a subdural space occupying lesion compressing the cauda equina at L5-S1 level producing a ‘Y’ shaped dural sac (Y sign), which was hyperintense on T1W imaging and hypointense to cord on T2W image. The STIR sequence showed hyperintensity to cord. There was no history of bleeding diathesis. The patient underwent decompressive durotomy and biopsy which confirmed the diagnosis. Conclusion: Spinal subdural hematoma may present with rapidly progressive neurological symptoms. MRI is the investigation of choice. The knowledge of MRI appearance with respect to the chronological stage of the bleed is essential to avoid diagnostic and hence surgical dilemma PMID:27299051

  18. [Spinal cord infarction].

    PubMed

    Naumann, N; Shariat, K; Ulmer, S; Stippich, C; Ahlhelm, F J

    2012-05-01

    Infarction of the spinal cord can cause a variety of symptoms and neurological deficits because of the complex vascular supply of the myelon. The most common leading symptom is distal paresis ranging from paraparesis to tetraplegia caused by arterial ischemia or infarction of the myelon. Venous infarction, however, cannot always be distinguished from arterial infarction based on the symptoms alone.Modern imaging techniques, such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) assist in preoperative planning of aortic operations to reliably identify not only the most important vascular structure supplying the spinal cord, the artery of Adamkiewicz, but also other pathologies such as tumors or infectious disorders. In contrast to CT, MRI can reliably depict infarction of the spinal cord.

  19. [Lumbar spinal angiolipoma].

    PubMed

    Isla, Alberto; Ortega Martinez, Rodrigo; Pérez López, Carlos; Gómez de la Riva, Alvaro; Mansilla, Beatriz

    2016-01-01

    Spinal angiolipomas are fairly infrequent benign tumours that are usually located in the epidural space of the thoracic column and represent 0.14% to 1.3% of all spinal tumours. Lumbar angiolipomas are extremely rare, representing only 9.6% of all spinal extradural angiolipomas. We report the case of a woman who complained of a lumbar pain of several months duration with no neurological focality and that had intensified in the last three days without her having had any injury or made a physical effort. The MR revealed an extradural mass L1-L2, on the posterior face of the medulla, decreasing the anteroposterior diameter of the canal. The patient symptoms improved after surgery. Total extirpation of the lesion is possible in most cases, and the prognosis is excellent even if the lesion is infiltrative. For this reason, excessively aggressive surgery is not necessary to obtain complete resection.

  20. Skiing and spinal trauma.

    PubMed

    Frymoyer, J W; Pope, M H; Kristiansen, T

    1982-07-01

    Spinal injury in skiers can either be acute or chronic. Acute spinal injury accounts for 3 to 3.6 per cent of all injuries occurring in Alpine skiing. Fewer acute injuries occur in cross-country skiing, and those that do usually are the result of a sudden, compressive force from a seated fall. The prevalence of chronic spinal trauma in skiing is unknown. Both cross-country and Alpine skiers appear to have greater complaints of mild to moderate low back pain as compared with their nonskiing counterparts. These differences may be the result of a complex interaction between recreational and occupational activities. Theoretical analyses suggest a risk for low-grade torsional injury to the Alpine skier's spine, whereas in cross-country skiing significant shear forces are applied to lumbar discs during the kick but not the double-poling phase.

  1. Lumbar spine visualisation based on kinematic analysis from videofluoroscopic imaging.

    PubMed

    Zheng, Y; Nixon, M S; Allen, R

    2003-04-01

    match the fluoroscopic image data. For animation, the spinal kinematic data from the motion study is incorporated.

  2. Changes in spinal alignment.

    PubMed

    Veintemillas Aráiz, M T; Beltrán Salazar, V P; Rivera Valladares, L; Marín Aznar, A; Melloni Ribas, P; Valls Pascual, R

    2016-04-01

    Spinal misalignments are a common reason for consultation at primary care centers and specialized departments. Misalignment has diverse causes and is influenced by multiple factors: in adolescence, the most frequent misalignment is scoliosis, which is idiopathic in 80% of cases and normally asymptomatic. In adults, the most common cause is degenerative. It is important to know the natural history and to detect factors that might predict progression. The correct diagnosis of spinal deformities requires specific imaging studies. The degree of deformity determines the type of treatment. The aim is to prevent progression of the deformity and to recover the flexibility and balance of the body.

  3. Recovery from Chronic Spinal Cord Contusion after Nogo Receptor Intervention

    PubMed Central

    Wang, Xingxing; Duffy, Philip; McGee, Aaron W.; Hasan, Omar; Gould, Grahame; Tu, Nathan; Harel, Noam Y.; Huang, Yiyun; Carson, Richard E.; Weinzimmer, David; Ropchan, Jim; Benowitz, Larry I.; Cafferty, William B. J.; Strittmatter, Stephen M.

    2011-01-01

    Objective Several interventions promote axonal growth and functional recovery when initiated shortly after CNS injury, including blockade of myelin-derived inhibitors with soluble Nogo Receptor (NgR1, RTN4R) ‘decoy’ protein. We examined the efficacy of this intervention in the much more prevalent and refractory condition of chronic spinal cord injury. Methods We eliminated the NgR1 pathway genetically in mice by conditional gene targeting starting 8 weeks after spinal hemisection injury and monitored locomotion in the open field and by video kinematics over the ensuing 4 months. In a separate pharmacological experiment, intrathecal NgR1 decoy protein administration was initiated 3 months after spinal cord contusion injury. Locomotion and raphespinal axon growth were assessed during 3 months of treatment between 4 and 6 months after contusion injury. Results Conditional deletion of NgR1 in the chronic state results in gradual improvement of motor function accompanied by increased density of raphespinal axons in the caudal spinal cord. In chronic rat spinal contusion, NgR1 decoy treatment from 4–6 months after injury results in 29% (10 of 35) of rats recovering weight-bearing status compared to 0% (0 of 29) of control rats (P<0.05). Open field BBB locomotor scores showed a significant improvement in the NgR-treated group relative to the control group (P<0.005, repeated measures ANOVA). An increase in raphespinal axon density caudal to the injury is detected in NgR1-decoy-treated animals by immunohistology and by positron emission tomography using a serotonin reuptake ligand. Interpretation Antagonizing myelin-derived inhibitors signaling with NgR1 decoy augments recovery from chronic spinal cord injury. PMID:22162062

  4. Functional kinematics of the wrist.

    PubMed

    Rainbow, M J; Wolff, A L; Crisco, J J; Wolfe, S W

    2016-01-01

    The purpose of this article is to review past and present concepts concerning functional kinematics of the healthy and injured wrist. To provide a context for students of the wrist, we describe the progression of techniques for measuring carpal kinematics over the past century and discuss how this has influenced today's understanding of functional kinematics. Next, we provide an overview of recent developments and highlight the clinical relevance of these findings. We use these findings and recent evidence that supports the importance of coupled motion in early rehabilitation of radiocarpal injuries to develop the argument that coupled motion during functional activities is a clinically relevant outcome; therefore, clinicians should develop a framework for its dynamic assessment. This should enable a tailored and individualized approach to the treatment of carpal injuries.

  5. An improved kinematic model of the spine for three-dimensional motion analysis in the Vicon system.

    PubMed

    Długosz, Mirosława M; Panek, Daria; Maciejasz, Paweł; Chwała, Wiesław; Alda, Witold

    2012-01-01

    The mechanism of creation and pathomechanics of lateral spinal deformation is still not fully explained. Modern medical imaging techniques give scientists possibility to understand some aspects, but vast majority of those techniques is based on static trials. A motion capture system belongs to techniques which enable visualization of a spine during dynamic trials; however, due to lack of appropriate computational model, it is unsuitable for scoliosis imaging. A few years ago our group has proposed a kinematic model of the spine to be used with Vicon Motion Capture System, which was based on Bézier curves. That model allowed for much more precise investigation of spinal kinematics during dynamic trials as compared with other computational models. However, it did not allowed to restrict only selected movements for particular segments of the spine (e.g. axial rotation for lumbar spine). The aim of the current work is to improve the proposed model in order to be able to restrict selected movements according to the knowledge concerning spinal anatomy and spinal range of motion. The new kinematic model of the spine was written in BodyBuilder for Biomechanics Language. For the purpose of visualization also an accurate graphical representation of each vertebra (polygon mesh) was computed and adapted to be compatible with the kinematic model. Using a new version of the model it is possible to perform precise analysis of movement of all vertebrae during such dynamic activities as e.g. gait and forward or lateral bending, as well as to present the results not only on the charts, but also as a 3D animation of movements of a realistically looking spine. The paper describes the new kinematic model and the process of creating graphical representation of the vertebrae. Also sample results obtained using that model are presented.

  6. Neurosurgical approaches to spinal infections.

    PubMed

    Hazer, Derya Burcu; Ayhan, Selim; Palaoglu, Selcuk

    2015-05-01

    Spinal infection is rare. Clinical suspicion is important in patients with nonmechanical neck and/or back pain to make the proper diagnosis in early disease. Before planning surgery, a thorough evaluation of the spinal stability, alignment, and deformity is necessary. Timing of surgery, side of approach, appropriate surgical technique, and spinal instruments used are crucial. Biomechanical preservation of the spinal column during and after the infection is a significant issue. Postoperative spine infection is another entity of which spinal surgeons should be aware of. Proper septic conditions with meticulous planning of surgery are essential for successful spine surgery and better outcome. PMID:25952179

  7. Forelimb EMG-based trigger to control an electronic spinal bridge to enable hindlimb stepping after a complete spinal cord lesion in rats

    PubMed Central

    2012-01-01

    Background A complete spinal cord transection results in loss of all supraspinal motor control below the level of the injury. The neural circuitry in the lumbosacral spinal cord, however, can generate locomotor patterns in the hindlimbs of rats and cats with the aid of motor training, epidural stimulation and/or administration of monoaminergic agonists. We hypothesized that there are patterns of EMG signals from the forelimbs during quadrupedal locomotion that uniquely represent a signal for the “intent” to step with the hindlimbs. These observations led us to determine whether this type of “indirect” volitional control of stepping can be achieved after a complete spinal cord injury. The objective of this study was to develop an electronic bridge across the lesion of the spinal cord to facilitate hindlimb stepping after a complete mid-thoracic spinal cord injury in adult rats. Methods We developed an electronic spinal bridge that can detect specific patterns of EMG activity from the forelimb muscles to initiate electrical-enabling motor control (eEmc) of the lumbosacral spinal cord to enable quadrupedal stepping after a complete spinal cord transection in rats. A moving window detection algorithm was implemented in a small microprocessor to detect biceps brachii EMG activity bilaterally that then was used to initiate and terminate epidural stimulation in the lumbosacral spinal cord. We found dominant frequencies of 180–220 Hz in the EMG of the forelimb muscles during active periods, whereas these frequencies were between 0–10 Hz when the muscles were inactive. Results and conclusions Once the algorithm was validated to represent kinematically appropriate quadrupedal stepping, we observed that the algorithm could reliably detect, initiate, and facilitate stepping under different pharmacological conditions and at various treadmill speeds. PMID:22691460

  8. Comprehensive assessment of walking function after human spinal cord injury.

    PubMed

    Awai, Lea; Curt, Armin

    2015-01-01

    Regaining any locomotor function after spinal cord injury is not only of immediate importance for affected patients but also for clinical research as it allows to investigate mechanisms underlying motor impairment and locomotor recovery. Clinical scores inform on functional outcomes that are clinically meaningful to value effects of therapy while they all lack the ability to explain underlying mechanisms of recovery. For this purpose, more elaborate recordings of walking kinematics combined with assessments of spinal cord conductivity and muscle activation patterns are required. A comprehensive assessment framework comprising of multiple complementary modalities is necessary. This will not only allow for capturing even subtle changes induced by interventions that are likely missed by standard clinical outcome measures. It will be fundamental to attribute observed changes to naturally occurring spontaneous recovery in contrast to specific changes induced by novel therapeutic interventions beyond the improvements achieved by conventional therapy.

  9. Kinematics of KPG 390

    NASA Astrophysics Data System (ADS)

    Repetto, P.; Rosado, M.; Gabbasov, R.; Fuentes-Carrera, I.

    2010-06-01

    In this work we present scanning Fabry-Perot Hα observations of the isolated interacting galaxy pair NGC 5278/9 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

  10. Computation of trunk muscle forces, spinal loads and stability in whole-body vibration

    NASA Astrophysics Data System (ADS)

    Bazrgari, B.; Shirazi-Adl, A.; Kasra, M.

    2008-12-01

    Whole-body vibration has been indicated as a risk factor in back disorders. Proper prevention and treatment management, however, requires a sound knowledge of associated muscle forces and loads on the spine. Previous trunk model studies have either neglected or over-simplified the trunk redundancy with time-varying unknown muscle forces. Trunk stability has neither been addressed. A novel iterative dynamic kinematics-driven approach was employed to evaluate muscle forces, spinal loads and system stability in a seated subject under a random vertical base excitation with ˜±1 g peak acceleration contents. This iterative approach satisfied equations of motion in all directions/levels while accounting for the nonlinear passive resistance of the ligamentous spine. The effect of posture, co-activity in abdominal muscles and changes in buttocks stiffness were also investigated. The computed vertical accelerations were in good agreement with measurements. The input base excitation, via inertial and muscle forces, substantially influenced spinal loads and system stability. The flexed posture in sitting increased the net moment, muscle forces and passive spinal loads while improving the trunk stability. Similarly, the introduction of low to moderate antagonistic coactivity in abdominal muscles increased the passive spinal loads and improved the spinal stability. A trade-off, hence, exists between lower muscle forces and spinal loads on one hand and more stable spine on the other. Base excitations with larger peak acceleration contents substantially increase muscle forces/spinal loads and, hence, the risk of injury.

  11. Spinal Cord Injury

    MedlinePlus

    ... How much do you know about taking good care of yourself? Links to more information girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home Illness & disability Types of ... Spinal cord injury Read advice from Dr. Jeffrey Rabin , a pediatric rehabilitation specialist at the Children’s National Medical Center. ...

  12. Maladaptive spinal plasticity opposes spinal learning and recovery in spinal cord injury

    PubMed Central

    Ferguson, Adam R.; Huie, J. Russell; Crown, Eric D.; Baumbauer, Kyle M.; Hook, Michelle A.; Garraway, Sandra M.; Lee, Kuan H.; Hoy, Kevin C.; Grau, James W.

    2012-01-01

    Synaptic plasticity within the spinal cord has great potential to facilitate recovery of function after spinal cord injury (SCI). Spinal plasticity can be induced in an activity-dependent manner even without input from the brain after complete SCI. A mechanistic basis for these effects is provided by research demonstrating that spinal synapses have many of the same plasticity mechanisms that are known to underlie learning and memory in the brain. In addition, the lumbar spinal cord can sustain several forms of learning and memory, including limb-position training. However, not all spinal plasticity promotes recovery of function. Central sensitization of nociceptive (pain) pathways in the spinal cord may emerge in response to various noxious inputs, demonstrating that plasticity within the spinal cord may contribute to maladaptive pain states. In this review we discuss interactions between adaptive and maladaptive forms of activity-dependent plasticity in the spinal cord below the level of SCI. The literature demonstrates that activity-dependent plasticity within the spinal cord must be carefully tuned to promote adaptive spinal training. Prior work from our group has shown that stimulation that is delivered in a limb position-dependent manner or on a fixed interval can induce adaptive plasticity that promotes future spinal cord learning and reduces nociceptive hyper-reactivity. On the other hand, stimulation that is delivered in an unsynchronized fashion, such as randomized electrical stimulation or peripheral skin injuries, can generate maladaptive spinal plasticity that undermines future spinal cord learning, reduces recovery of locomotor function, and promotes nociceptive hyper-reactivity after SCI. We review these basic phenomena, how these findings relate to the broader spinal plasticity literature, discuss the cellular and molecular mechanisms, and finally discuss implications of these and other findings for improved rehabilitative therapies after SCI. PMID

  13. Top quark mass and kinematics

    SciTech Connect

    Barberis, Emanuela; /Northeastern U.

    2006-05-01

    A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.

  14. Kinematic Parameters of Signed Verbs

    ERIC Educational Resources Information Center

    Malaia, Evie; Wilbur, Ronnie B.; Milkovic, Marina

    2013-01-01

    Purpose: Sign language users recruit physical properties of visual motion to convey linguistic information. Research on American Sign Language (ASL) indicates that signers systematically use kinematic features (e.g., velocity, deceleration) of dominant hand motion for distinguishing specific semantic properties of verb classes in production…

  15. Aspergillus spinal epidural abscess

    SciTech Connect

    Byrd, B.F. III; Weiner, M.H.; McGee, Z.A.

    1982-12-17

    A spinal epidural abscess developed in a renal transplant recipient; results of a serum radioimmunoassay for Aspergillus antigen were positive. Laminectomy disclosed an abscess of the L4-5 interspace and L-5 vertebral body that contained hyphal forms and from which Aspergillus species was cultured. Serum Aspergillus antigen radioimmunoassay may be a valuable, specific early diagnostic test when systemic aspergillosis is a consideration in an immunosuppressed host.

  16. FAQs about Spinal Cord Injury (SCI)

    MedlinePlus

    ... Website Managing Bowel Function After Spinal Cord Injury Resilience, Depression and Bouncing Back after SCI Getting to ... a “complete” and “incomplete” spinal cord injury? What recovery is expected following spinal cord injury? Where is ...

  17. The Stellar Kinematics of Several Irregular Galaxies

    NASA Astrophysics Data System (ADS)

    Hunter, D. A.; Rubin, V. C.; Swaters, R. A.

    2001-12-01

    We present long-slit spectra of three irregular galaxies from which we determine the stellar kinematics in two of the galaxies (NGC 1156 and NGC 4449) and ionized-gas kinematics in all three (including NGC 2366). We compare the stellar and ionized gas kinematics to the morphology of the galaxies and their HI kinematics. We find surprising differences between the kinematics of the stars, ionized gas, and neutral gas in these systems. Support for this work was provided to DAH by the Lowell Research Fund and by the National Science Foundation through grant AST-9616940.

  18. Exploring MaNGA's kinematic maps

    NASA Astrophysics Data System (ADS)

    Weijmans, Anne-Marie; MaNGA Team

    2016-01-01

    Different galaxy formation processes leave different imprints on the gas and stellar kinematic patterns for a galaxy. With MaNGA, we now have after one year of observations an unprecedented sample of 1400 nearby galaxies for which we can study gas and stellar kinematics in much detail, based on integral-field spectroscopy. We are measuring kinematic quantities such as LambdaR (angular momentum) and their (possible) correlations with other galaxy properties such as mass, morphology and environment. By quantifying the kinematic (sub)structures in velocity and dispersion maps, we will construct a kinematic galaxy classification that can be linked to their formation processes.

  19. Cerebral spinal fluid (CSF) collection

    MedlinePlus

    Spinal tap; Ventricular puncture; Lumbar puncture; Cisternal puncture; Cerebrospinal fluid culture ... brain stem. It is always done with fluoroscopy. Ventricular puncture may be recommended in people with possible ...

  20. Spinal angiolipoma--case report.

    PubMed

    Chotai, Silky; Hur, Jun Seok; Moon, Hong Joo; Kwon, Taek-Hyun; Park, Youn Kwan; Kim, Joo Han

    2011-01-01

    A 69-year-old male presented with a rare spinal angiolipoma manifesting as history of back pain, and numbness in both lower limbs, which progressed over a period of 5 years. Total T10-T12 laminectomy was performed and the tumor was removed en bloc. The symptoms gradually improved postoperatively. Spinal angiolipoma is an uncommon benign extradural tumor of spine, which accounts for 0.14-1.2% of all spinal tumors and is a rare cause of spinal cord compression. Recognition of this entity is crucial as a benign and curable cause of paraplegia and back pain.

  1. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Mattione, Paul

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  2. Pythagoras Theorem and Relativistic Kinematics

    NASA Astrophysics Data System (ADS)

    Mulaj, Zenun; Dhoqina, Polikron

    2010-01-01

    In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.

  3. Of cilium and flagellum kinematics

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Promode R.; Hansen, Joshua C.

    2009-11-01

    The kinematics of propulsion of small animals such as paramecium and spermatozoa is considered. Larger scale models of the cilium and flagellum have been built and a four-motor apparatus has been constructed to reproduce their known periodic motions. The cilium model has transverse deformational ability in one plane only, while the flagellum model has such ability in two planes. When the flagellum model is given a push-pull in one diametral plane, instead of transverse deflection in one plane, it forms a coil. Berg & Anderson's postulation (Nature 245 1973) that a flagellum rotates, is recalled. The kinematics of cilia of paramecium, of the whipping motion of the spermatozoa flagella, and of the flapping motion (rolling and pitching) of the pectoral fins of much larger animals such penguins, have been reproduced in the same basic paramecium apparatus. The results suggest that each of the tiny individual paramecium propulsors have the intrinsic dormant kinematic and structural building blocks to optimize into higher Reynolds number propulsors. A synthetic hypothesis on how small might have become large is animated.

  4. An in vitro spinal cord-hindlimb preparation for studying behaviorally relevant rat locomotor function.

    PubMed

    Hayes, Heather Brant; Chang, Young-Hui; Hochman, Shawn

    2009-02-01

    Although the spinal cord contains the pattern-generating circuitry for producing locomotion, sensory feedback reinforces and refines the spatiotemporal features of motor output to match environmental demands. In vitro preparations, such as the isolated rodent spinal cord, offer many advantages for investigating locomotor circuitry, but they lack the natural afferent feedback provided by ongoing locomotor movements. We developed a novel preparation consisting of an isolated in vitro neonatal rat spinal cord oriented dorsal-up with intact hindlimbs free to step on a custom-built treadmill. This preparation combines the neural accessibility of in vitro preparations with the modulatory influence of sensory feedback from physiological hindlimb movement. Locomotion induced by N-methyl D-aspartate and serotonin showed kinematics similar to that of normal adult rat locomotion. Changing orientation and ground interaction (dorsal-up locomotion vs ventral-up air-stepping) resulted in significant kinematic and electromyographic changes that were comparable to those reported under similar mechanical conditions in vivo. We then used two mechanosensory perturbations to demonstrate the influence of sensory feedback on in vitro motor output patterns. First, swing assistive forces induced more regular, robust muscle activation patterns. Second, altering treadmill speed induced corresponding changes in stride frequency, confirming that changes in sensory feedback can alter stride timing in vitro. In summary, intact hindlimbs in vitro can generate behaviorally appropriate locomotor kinematics and responses to sensory perturbations. Future studies combining the neural and chemical accessibility of the in vitro spinal cord with the influence of behaviorally appropriate hindlimb movements will provide further insight into the operation of spinal motor pattern-generating circuits.

  5. Spinal bone density following spinal fusion

    SciTech Connect

    Lipscomb, H.J.; Grubb, S.A.; Talmage, R.V.

    1989-04-01

    Spinal bone densities were assessed in 25 patients following lumbar fusion and bracing, in an attempt to study bone remodeling by noninvasive methods. Dual-photon densitometry was used to study specific areas of autologous bone grafts and adjacent vertebrae above the fusion mass. Measurements were made preoperatively and at 6-week intervals postoperatively. The data for the first 12 months postoperatively are reported here. In all patients there was at first a consistent loss in density in the vertebrae above the fusion mass, averaging 15.7%. This was followed by a gradual density increase such that by 1 year postoperatively, in 60% of the subjects, the density of these vertebrae was higher than the preoperative level. In the grafted areas, bone changes were cyclical, demonstrating a remodeling pattern consistent with that described in animal literature for graft healing and also consistent with modern bone remodeling theory. There was a general tendency toward a gradual increase in the density of the fusion mass.

  6. Spinal Injury Rehabilitation in Singapore.

    ERIC Educational Resources Information Center

    Yen, H. L.; Chua, K.; Chan, W.

    1998-01-01

    This study reviewed 231 cases of spinal cord injury treated in Singapore. Data on demographic characteristics, common causes (mostly falls and traffic accidents), types of spinal damage, and outcomes are reported. Following rehabilitation, 68 patients were able to ambulate independently and 45 patients achieved independence in activities of daily…

  7. Adjustment to Spinal Cord Injury

    MedlinePlus

    ... of injury are alive and easily get educational information on the Internet. Web happy. sites such as the National Spinal Cord Injury Association (www.spinalcord.org) and SPINAL CORD Injury ♦ “Because of my injury, it is now impossible for me Information Network (www.spinalcord.uab.edu) have to ever ...

  8. Hemorrhagic onset of spinal angiolipoma.

    PubMed

    da Costa, Marcos Devanir Silva; Paz, Daniel de Araujo; Rodrigues, Thiago Pereira; Gandolfi, Ana Camila de Castro; Lamis, Fabricio Correa; Stavale, João Norberto; Suriano, Italo Capraro; Cetl, Luiz Daniel Marques Neves; Cavalheiro, Sergio

    2014-12-01

    Spinal angiolipomas are rare benign tumors that generally induce slow progressive cord compression. Here, the authors describe a case of sudden-onset palsy of the lower extremities caused by hemorrhagic spinal angiolipoma. An emergent laminectomy was performed to achieve total lesion removal. Follow-up examinations indicated neurological improvement and the absence of recurrence.

  9. Imaging modalities in spinal disorders

    SciTech Connect

    Kricun, M.E.

    1986-01-01

    This book provides an approach to the various imaging modalities used to view the spine. It discusses the indications, limitations and practical use of each in the diagnosis, work-up and staging of various spinal disorders, and compares each of them in various clinical settings. Topics covered include low back pain syndrome, disk disease, spinal cord lesions, congenital abnormalities, and trauma.

  10. Assessment of spinal pain.

    PubMed

    Braun, J; Baraliakos, X; Regel, A; Kiltz, U

    2014-12-01

    Spinal pain or back pain is a very common symptom that can have many reasons. The most studied location is low back pain, and it is considered to be nonspecific in the majority of cases. Only a small proportion of patients have axial inflammation as the major cause of their back complaints with chronic inflammatory back pain (IBP) as the most prominent clinical feature of spondyloarthritis (SpA). The recognition of IBP and patients with axial spondyloarthritis (axSpA) is challenging in primary care, and it is important to further facilitate the early diagnosis of SpA. Proposals for improving the referral of patients with a possible diagnosis of axSpA include clinical parameters, human leukocyte antigen (HLA) B27, and imaging parameters. Imaging is crucial for the visualization, objective validation, and understanding of back pain. Numerous diseases such as degenerative disk disease, degenerative changes in the intervertebral (facet) joints and the associated ligaments, spinal instability, herniation of the intervertebral disk, and spinal stenosis have to be differentiated in interpreting imaging of the spine. The sacroiliac joints and the spine are of major importance for the diagnosis and classification of axSpA. Conventional radiographs and magnetic resonance imaging (MRI) are the most important imaging technologies for visualization of structural changes such as syndesmophytes and axial inflammation such as sacroiliitis and spondylitis. The pathogenesis of axSpA is largely genetically determined. HLA B27 has the strongest contribution to the total genetic burden, but other major contributors such as endoplasmic reticulum aminopeptidase (ERAP)-1 and interleukin (IL)-23R have also been identified. PMID:26096091

  11. Infiltrating spinal angiolipoma.

    PubMed

    Yen, Han-Lin; Tsai, Shih-Chung; Liu, Shian-Min

    2008-10-01

    Infiltrating angiolipomas are rarely encountered in the spine. We present a case involving a 71-year-old man with a dorsal epidural angiolipoma at the T5-T7 level. The tumor involved the T5-T6 vertebral bodies and left pedicle. The patient presented with acute paraparesis and MRI showed a homogeneously hyphointense lesion on T1-weighted images. The epidural component of the tumor was removed via laminectomy to achieve adequate cord decompression. The patient was symptom-free at a 2-year follow-up. This report emphasizes the unusual clinical presentation and MRI features of an infiltrating spinal angiolipoma and discusses therapeutic management options.

  12. Lumbar spinal epidural angiolipoma.

    PubMed

    Nanassis, Kimon; Tsitsopoulos, Parmenion; Marinopoulos, Dimitrios; Mintelis, Apostolos; Tsitsopoulos, Philippos

    2008-04-01

    Spinal angiolipomas are rare benign tumours most commonly found in the thoracic spine. A case of an extradural lumbar angiolipoma in a 47-year-old female is described. She had a recent history of lower back pain accompanied by sciatica. Lumbar MRI revealed a dorsal epidural mass at the L2-L3 level. The patient underwent a bilateral laminectomy, in which the tumour was totally excised. The pathological examination indicated haemangiolipoma. Post-operatively, the patient's neurological signs and symptoms improved remarkably quickly. MRI at 6 and 18 months after surgery revealed no evidence of tumour recurrence.

  13. Treadmill training in incomplete spinal cord injured rats.

    PubMed

    Fouad, K; Metz, G A; Merkler, D; Dietz, V; Schwab, M E

    2000-10-01

    Treadmill training has been shown to accelerate locomotor recovery and to improve weight bearing during treadmill walking in spinal cats. In human patients treadmill training is increasingly used in rehabilitation after incomplete spinal cord injury. In this study we examined training effects in spinal cord injured rats with an incomplete dorsal lesion. Recovery was examined with an open field locomotor score, kinematic analysis on the treadmill, and several functional tests (i.e. foot print evaluation, narrow beam crossing, grid walking, open field exploratory activity). During the course of 5 weeks after the injury, a substantial amount of recovery occurred in the treadmill trained as well as in the untrained rats. If compared to the control lesioned rats, which showed a high level of spontaneous hindlimb movements at 7-14 days post lesion, no additional beneficial effect of a 5-week daily treadmill training on the locomotor outcome could be detected in the trained group. The only change observed was a slightly larger exploratory activity of the trained rats. It is probable that the spared ventral and ventro-lateral fibers allowed spontaneous recovery and 'self-training' to occur to such an extend that systematic treadmill training did not provide additional improvement. PMID:10996413

  14. A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs.

    PubMed

    Swaminathan, Ramesh; Williams, Jonathan M; Jones, Michael D; Theobald, Peter S

    2016-01-01

    Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario. PMID:26375051

  15. A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs

    PubMed Central

    Swaminathan, Ramesh; Williams, Jonathan M.; Jones, Michael D.; Theobald, Peter S.

    2016-01-01

    ABSTRACT Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario. PMID:26375051

  16. Kinematic correction for roller skewing

    NASA Technical Reports Server (NTRS)

    Savage, M.; Loewenthal, S. H.

    1980-01-01

    A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to product changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

  17. Relativistic kinematics and stationary motions

    NASA Astrophysics Data System (ADS)

    Russo, Jorge G.; Townsend, Paul K.

    2009-11-01

    The relativistic jerk, snap and all higher-order kinematical D-vectors are defined for the motion of a massive particle in a D-dimensional Minkowski spacetime. We illustrate the formalism with stationary motions, for which we provide a new, Lorentz covariant, classification. We generalize some cases to branes, explaining the relevance to uniform motion in a heat bath. We also consider some non-stationary motions, including motion with constant proper jerk, and free fall into a black hole as viewed from a GEMS perspective.

  18. Early experience with endoscopic revision of lumbar spinal fusions.

    PubMed

    McGrath, Lynn B; Madhavan, Karthik; Chieng, Lee Onn; Wang, Michael Y; Hofstetter, Christoph P

    2016-02-01

    Approximately half a million spinal fusion procedures are performed annually in the US. It is estimated that up to one-third of arthrodesis constructs require revision surgeries. In this study the authors present endoscopic treatment strategies targeting 3 types of complications following arthrodesis surgery: 1) adjacent-level foraminal stenosis; 2) foraminal stenosis at an arthrodesis segment; and 3) stenosis caused by a displaced interbody cage. A retrospective chart review of 11 patients with a mean age of 68 ± 15 years was performed (continuous variables are shown as the mean ± SEM). All patients had a history of lumbar arthrodesis surgery and suffered from unilateral radiculopathy. Endoscopic revision surgeries were done as outpatient procedures, and there were no intraoperative or perioperative complications. The cohort included 3 patients with foraminal stenosis at the level of previous arthrodesis. They presented with unilateral radicular leg pain (visual analog scale [VAS] score: 7.3 ± 2.1) and were severely disabled, as evidenced by an Oswestry Disability Index (ODI) of 46 ± 4.9. Transforaminal endoscopic foraminotomies were performed, and at a mean follow-up time of 9.0 ± 2.5 months VAS was reduced by an average of 6.3. The cohort also includes 7 patients suffering unilateral radiculopathy due to adjacent-level foraminal stenosis. Preoperative VAS for leg pain of the symptomatic side was 6.0 ± 1.6, VAS for back pain was 5.2 ± 1.7, and ODI was 40 ± 6.33. Endoscopic decompression led to reduction of the ipsilateral leg VAS score by an average of 5, resulting in leg pain of 1 ± 0.5 at an average of 8 months of follow-up. The severity of back pain remained stable (VAS 4.2 ± 1.4). Two of these patients required revision surgery for recurrent symptoms. Finally, this study includes 1 patient who presented with weakness and pain due to retropulsion of an L5/S1 interbody spacer. The patient underwent an endoscopic interlaminar approach with partial

  19. Attitudes Towards Individuals with Spinal Cord Injuries

    ERIC Educational Resources Information Center

    Conway, Cassandra Sligh D.; Gooden, Randy; Nowell, Jennifer; Wilson, Navodda

    2010-01-01

    This paper will shed light on the lives of persons with spinal cord injuries by revealing the literature on spinal cord injuries that focuses on research that can shed light on attitudes towards persons with spinal cord injuries. The background literature related to incidences, the definition of spinal cord injury, and vocational opportunities are…

  20. Spinal epidural angiolipoma: A rare cause of spinal cord compression.

    PubMed

    Ghanta, Rajesh K; Koti, Kalyan; Dandamudi, Srinivas

    2012-09-01

    Spinal epidural angiolipomas are rare, benign tumors composed of mature lipocytes admixed with abnormal blood vessels. Only 128 cases of spinal epidural angiolipomas have been reported in literature till now. Spinal angiolipomas are predominantly located in the mid-thoracic region. We report a case of dorsal epidural angiolipoma in a 56-year-old male who presented with paraparesis and was diagnosed to have D4-5 epidural angiolipoma. Total surgical excision of the epidural angiolipoma was done and his paraparesis gradually improved.

  1. Basic concepts of kinematic-wave models

    USGS Publications Warehouse

    Miller, J.E.

    1984-01-01

    The kinematic-wave model is one of a number of approximations of the dynamic-wave model. The dynamic-wave model describes one-dimensional shallow-water waves (unsteady, gradually varied, open-channel flow). The report provides a basic reference on the theory and application of kinematic-wave models and describes the limitations of the model in relation to the other approximations of the dynamic-wave model. In the kinematic-wave approximation, a number of the terms in the equation of motion are assumed to be insignificant. The equation of motion is replaced by an equation describing uniform flow. Thus, the kinematic-wave model is described by the continuity equation and a uniform flow equation such as the well-known Chezy or Manning formulas. Kinematic-wave models are applicable to overland flow where lateral inflow is continuously added and is a large part of the total flow. For channel-routing applications, the kinematic-wave model always predicts a steeper wave with less dispersion and attenuation than actually occurs. The effect of the accumulation of errors in the kinematic-wave model shows that the approximations made in the development of the kinematic-wave equations are not generally justified for most channel-routing applications. Modified flow-routing models can be used which help to stop the accumulation of error that occurs when the kinematic-wave model is applied. (USGS)

  2. Ballistic representation for kinematic access

    NASA Astrophysics Data System (ADS)

    Alfano, Salvatore

    2011-01-01

    This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

  3. Spinal Plasticity following Intermittent Hypoxia: Implications for Spinal Injury

    PubMed Central

    Dale-Nagle, Erica A.; Hoffman, Michael S.; MacFarlane, Peter M.; Satriotomo, Irawan; Lovett-Barr, Mary Rachael; Vinit, Stéphane; Mitchell, Gordon S.

    2011-01-01

    Plasticity is a fundamental property of the neural system controlling breathing. One frequently studied model of respiratory plasticity is long-term facilitation of phrenic motor output (pLTF) following acute intermittent hypoxia (AIH). pLTF arises from spinal plasticity, increasing respiratory motor output through a mechanism that requires new synthesis of brain derived neurotrophic factor (BDNF), activation of its high affinity receptor, tropomyosin-related kinase B (TrkB) and extracellular-related kinase (ERK) mitogen-activated protein (MAP) kinase signaling in or near phrenic motor neurons. Since intermittent hypoxia induces spinal plasticity, we are exploring the potential to harness repetitive AIH as a means of inducing functional recovery in conditions causing respiratory insufficiency, such as cervical spinal injury. Since repetitive AIH induces phenotypic plasticity in respiratory and motor neurons, it may restore respiratory motor function in patients with incomplete spinal injury. PMID:20536940

  4. Spinal Chondrosarcoma: A Review

    PubMed Central

    Katonis, Pavlos; Alpantaki, Kalliopi; Michail, Konstantinos; Lianoudakis, Stratos; Christoforakis, Zaharias; Tzanakakis, George; Karantanas, Apostolos

    2011-01-01

    Chondrosarcoma is the third most common primary malignant bone tumor. Yet the spine represents the primary location in only 2% to 12% of these tumors. Almost all patients present with pain and a palpable mass. About 50% of patients present with neurologic symptoms. Chemotherapy and radiotherapy are generally unsuccessful while surgical resection is the treatment of choice. Early diagnosis and careful surgical staging are important to achieve adequate management. This paper provides an overview of the histopathological classification, clinical presentation, and diagnostic procedures regarding spinal chondrosarcoma. We highlight specific treatment modalities and discuss which is truly the most suitable approach for these tumors. Abstracts and original articles in English investigating these tumors were searched and analyzed with the use of the PubMed and Scopus databases with “chondrosarcoma and spine” as keywords. PMID:21437176

  5. Simulation in spinal diseases.

    PubMed

    Aso Escario, José; Martínez Quiñones, José Vicente; Aso Vizán, Alberto; Arregui Calvo, Ricardo; Bernal Lafuente, Marta; Alcázar Crevillén, Andrés

    2014-01-01

    Simulation is frequent in spinal disease, resulting in problems for specialists like Orthopedic Surgeons, Neurosurgeons, Reumathologists, etc. Simulation requires demonstration of the intentional production of false or exaggerated symptoms following an external incentive. The clinician has difficulties in demonstrating these criteria, resulting in misdiagnosis of simulation or misinterpretation of the normal patient as a simulator, with the possibility of iatrogenic distress and litigation. We review simulation-related problems in spine, proposing a terminological, as well as a diagnostic strategy including clinical and complementary diagnosis, as a way to avoid misinterpretation and minimize the iatrogenic distress and liability Based on the clinical-Forensic author's expertise, the literature is analyzed and the terminology readdressed to develop new terms (inconsistences, incongruences, discrepancies and contradictions). Clinical semiology and complementary test are adapted to the new scenario. Diagnostic strategy relies on anamnesis, clinical and complementary tests, adapting them to a uniform terminology with clear meaning of signs and symptoms.

  6. Simulation in spinal diseases.

    PubMed

    Aso Escario, José; Martínez Quiñones, José Vicente; Aso Vizán, Alberto; Arregui Calvo, Ricardo; Bernal Lafuente, Marta; Alcázar Crevillén, Andrés

    2014-01-01

    Simulation is frequent in spinal disease, resulting in problems for specialists like Orthopedic Surgeons, Neurosurgeons, Reumathologists, etc. Simulation requires demonstration of the intentional production of false or exaggerated symptoms following an external incentive. The clinician has difficulties in demonstrating these criteria, resulting in misdiagnosis of simulation or misinterpretation of the normal patient as a simulator, with the possibility of iatrogenic distress and litigation. We review simulation-related problems in spine, proposing a terminological, as well as a diagnostic strategy including clinical and complementary diagnosis, as a way to avoid misinterpretation and minimize the iatrogenic distress and liability Based on the clinical-Forensic author's expertise, the literature is analyzed and the terminology readdressed to develop new terms (inconsistences, incongruences, discrepancies and contradictions). Clinical semiology and complementary test are adapted to the new scenario. Diagnostic strategy relies on anamnesis, clinical and complementary tests, adapting them to a uniform terminology with clear meaning of signs and symptoms. PMID:24913963

  7. Kinematics of the free throw in basketball

    NASA Astrophysics Data System (ADS)

    Tan, A.; Miller, G.

    1981-06-01

    The kinematics of the two basic styles of free throw in basketball are discussed. It is shown that from a purely kinematic and trajectory point of view, the overhand push shot is preferable to the underhand loop shot. The advantages of the underhand shot lie in the actual execution of the shot.

  8. Diffusion Tensor Imaging as a Predictor of Locomotor Function after Experimental Spinal Cord Injury and Recovery

    PubMed Central

    Kelley, Brian J.; Harel, Noam Y.; Kim, Chang-Yeon; Papademetris, Xenophon; Coman, Daniel; Wang, Xingxing; Hasan, Omar; Kaufman, Adam; Globinsky, Ronen; Staib, Lawrence H.; Cafferty, William B.J.; Hyder, Fahmeed

    2014-01-01

    Abstract Traumatic spinal cord injury (SCI) causes long-term disability with limited functional recovery linked to the extent of axonal connectivity. Quantitative diffusion tensor imaging (DTI) of axonal integrity has been suggested as a potential biomarker for prognostic and therapeutic evaluation after trauma, but its correlation with functional outcomes has not been clearly defined. To examine this application, female Sprague-Dawley rats underwent midthoracic laminectomy followed by traumatic spinal cord contusion of differing severities or laminectomy without contusion. Locomotor scores and hindlimb kinematic data were collected for 4 weeks post-injury. Ex vivo DTI was then performed to assess axonal integrity using tractography and fractional anisotropy (FA), a numerical measure of relative white matter integrity, at the injury epicenter and at specific intervals rostral and caudal to the injury site. Immunohistochemistry for tissue sparing was also performed. Statistical correlation between imaging data and functional performance was assessed as the primary outcome. All injured animals showed some recovery of locomotor function, while hindlimb kinematics revealed graded deficits consistent with injury severity. Standard T2 magnetic resonance sequences illustrated conventional spinal cord morphology adjacent to contusions while corresponding FA maps indicated graded white matter pathology within these adjacent regions. Positive correlations between locomotor (Basso, Beattie, and Bresnahan score and gait kinematics) and imaging (FA values) parameters were also observed within these adjacent regions, most strongly within caudal segments beyond the lesion. Evaluation of axonal injury by DTI provides a mechanism for functional recovery assessment in a rodent SCI model. These findings suggest that focused DTI analysis of caudal spinal cord should be studied in human cases in relationship to motor outcome to augment outcome biomarkers for clinical cases. PMID

  9. Overview of Spinal Cord Disorders

    MedlinePlus

    ... temperature from the body to the spinal cord. Did You Know... Doctors can often tell where the ... on symptoms and results of a physical examination. Did You Know... Nerves from the lowest parts of ...

  10. What Is Spinal Cord Injury?

    MedlinePlus

    ... lowest point on the spinal cord below which sensory feeling and motor movement diminish or disappear. The ... injury is so severe that almost all feeling (sensory function) and all ability to control movement (motor ...

  11. Leuprolide acetate induces structural and functional recovery of injured spinal cord in rats

    PubMed Central

    Díaz Galindo, Carmen; Gómez-González, Beatriz; Salinas, Eva; Calderón-Vallejo, Denisse; Hernández-Jasso, Irma; Bautista, Eduardo; Quintanar, J Luis

    2015-01-01

    Gonadotropin-releasing hormone (GnRH) and its synthetic analog leuprolide acetate, a GnRH agonist, have neurotrophic properties. This study was designed to determine whether administration of leuprolide acetate can improve locomotor behavior, gait, micturition reflex, spinal cord morphology and the amount of microglia in the lesion epicenter after spinal cord injury in rats. Rats with spinal cord compression injury were administered leuprolide acetate or saline solution for 5 weeks. At the 5th week, leuprolide acetate-treated rats showed locomotor activity recovery by 38%, had improvement in kinematic gait and exhibited voiding reflex recovery by 60%, as compared with the 1st week. By contrast, saline solution-treated rats showed locomotor activity recovery only by 7%, but voiding reflex did not recover. More importantly, leuprolide acetate treatment reduced microglial immunological reaction and induced a trend towards greater area of white and gray matter in the spinal cord. Therefore, leuprolide acetate has great potential to repair spinal cord injury. PMID:26807118

  12. Leuprolide acetate induces structural and functional recovery of injured spinal cord in rats.

    PubMed

    Díaz Galindo, Carmen; Gómez-González, Beatriz; Salinas, Eva; Calderón-Vallejo, Denisse; Hernández-Jasso, Irma; Bautista, Eduardo; Quintanar, J Luis

    2015-11-01

    Gonadotropin-releasing hormone (GnRH) and its synthetic analog leuprolide acetate, a GnRH agonist, have neurotrophic properties. This study was designed to determine whether administration of leuprolide acetate can improve locomotor behavior, gait, micturition reflex, spinal cord morphology and the amount of microglia in the lesion epicenter after spinal cord injury in rats. Rats with spinal cord compression injury were administered leuprolide acetate or saline solution for 5 weeks. At the 5(th) week, leuprolide acetate-treated rats showed locomotor activity recovery by 38%, had improvement in kinematic gait and exhibited voiding reflex recovery by 60%, as compared with the 1(st) week. By contrast, saline solution-treated rats showed locomotor activity recovery only by 7%, but voiding reflex did not recover. More importantly, leuprolide acetate treatment reduced microglial immunological reaction and induced a trend towards greater area of white and gray matter in the spinal cord. Therefore, leuprolide acetate has great potential to repair spinal cord injury.

  13. Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

    PubMed Central

    Bazrgari, Babak; Arjmand, Navid

    2006-01-01

    Despite the well-recognized role of lifting in back injuries, the relative biomechanical merits of squat versus stoop lifting remain controversial. In vivo kinematics measurements and model studies are combined to estimate trunk muscle forces and internal spinal loads under dynamic squat and stoop lifts with and without load in hands. Measurements were performed on healthy subjects to collect segmental rotations during lifts needed as input data in subsequent model studies. The model accounted for nonlinear properties of the ligamentous spine, wrapping of thoracic extensor muscles to take curved paths in flexion and trunk dynamic characteristics (inertia and damping) while subject to measured kinematics and gravity/external loads. A dynamic kinematics-driven approach was employed accounting for the spinal synergy by simultaneous consideration of passive structures and muscle forces under given posture and loads. Results satisfied kinematics and dynamic equilibrium conditions at all levels and directions. Net moments, muscle forces at different levels, passive (muscle or ligamentous) forces and internal compression/shear forces were larger in stoop lifts than in squat ones. These were due to significantly larger thorax, lumbar and pelvis rotations in stoop lifts. For the relatively slow lifting tasks performed in this study with the lowering and lifting phases each lasting ∼2 s, the effect of inertia and damping was not, in general, important. Moreover, posterior shift in the position of the external load in stoop lift reaching the same lever arm with respect to the S1 as that in squat lift did not influence the conclusion of this study on the merits of squat lifts over stoop ones. Results, for the tasks considered, advocate squat lifting over stoop lifting as the technique of choice in reducing net moments, muscle forces and internal spinal loads (i.e., moment, compression and shear force). PMID:17103232

  14. Short term modulation of trunk neuromuscular responses following spinal manipulation: a control group study

    PubMed Central

    2013-01-01

    Background Low back pain (LBP) is one of the most frequent musculoskeletal conditions in industrialized countries and its economic impact is important. Spinal manipulation therapy (SMT) is believed to be a valid approach in the treatment of both acute and chronic LBP. It has also been shown that SMT can modulate the electromyographic (EMG) activity of the paraspinal muscle. The purpose of this study was to investigate, in a group of patients with low back pain, the persistence of changes observed in trunk neuromuscular responses after a spinal manipulation (SMT). Methods Sixty adult participants with LBP performed a block of 5 flexion-extension movements. Participants in the experimental group (n=30) received lumbar SMT whereas participants in the control group (n=30) were positioned similarly for the treatment but did not receive SMT. Blocks of flexion-extension movements were repeated immediately after the manipulation as well as 5 and 30 minutes after SMT (or control position). EMG activity of paraspinal muscles was recorded at L2 and L5 level and kinematic data were collected to evaluate the lumbo-pelvic kinematics. Pain intensity was noted after each block. Normalized EMG, pain intensity and lumbo-pelvic kinematics were compared across experimental conditions. Results Participants from the control group showed a significant increase in EMG activity during the last block (30 min) of flexion-extension trials in both flexion and full-flexion phases at L2. Increase in VAS scores was also observed in the last 2 blocks (5 min and 30 min) in the control group. No significant group x time interaction was seen at L5. No significant difference was observed in the lumbo-pelvic kinematics. Conclusion Changes in trunk neuromuscular control following HVLA spinal manipulation may reduce sensitization or muscle fatigue effects related to repetitive movement. Future studies should investigate short term changes in neuromuscular components, tissue properties and clinical

  15. On the kinematic analysis of robotic mechanisms

    SciTech Connect

    Nielsen, J.; Roth, B.

    1999-12-01

    The kinematic analyses, of manipulators and other robotic devices composed of mechanical links, usually depend on the solution of sets of nonlinear equations. There are a variety of both numerical and algebraic techniques available to solve such systems of equations and to give bounds on the number of solutions. These solution methods have also led to an understanding of how special choices of the various structural parameters of a mechanism influence the number of solutions inherent to the kinematic geometry of a given structure. In this paper, results from studying the kinematic geometry of such systems are reviewed, and the three most useful solution techniques are summarized. The solution techniques are polynomial continuation, Groebner bases, and elimination. The authors then discuss the results that have been obtained with these techniques in the solution of two basic problems, namely, the inverse kinematics for serial-chain manipulators, and the direct kinematics of in-parallel platform devices.

  16. Bayesian kinematic earthquake source models

    NASA Astrophysics Data System (ADS)

    Minson, S. E.; Simons, M.; Beck, J. L.; Genrich, J. F.; Galetzka, J. E.; Chowdhury, F.; Owen, S. E.; Webb, F.; Comte, D.; Glass, B.; Leiva, C.; Ortega, F. H.

    2009-12-01

    Most coseismic, postseismic, and interseismic slip models are based on highly regularized optimizations which yield one solution which satisfies the data given a particular set of regularizing constraints. This regularization hampers our ability to answer basic questions such as whether seismic and aseismic slip overlap or instead rupture separate portions of the fault zone. We present a Bayesian methodology for generating kinematic earthquake source models with a focus on large subduction zone earthquakes. Unlike classical optimization approaches, Bayesian techniques sample the ensemble of all acceptable models presented as an a posteriori probability density function (PDF), and thus we can explore the entire solution space to determine, for example, which model parameters are well determined and which are not, or what is the likelihood that two slip distributions overlap in space. Bayesian sampling also has the advantage that all a priori knowledge of the source process can be used to mold the a posteriori ensemble of models. Although very powerful, Bayesian methods have up to now been of limited use in geophysical modeling because they are only computationally feasible for problems with a small number of free parameters due to what is called the "curse of dimensionality." However, our methodology can successfully sample solution spaces of many hundreds of parameters, which is sufficient to produce finite fault kinematic earthquake models. Our algorithm is a modification of the tempered Markov chain Monte Carlo (tempered MCMC or TMCMC) method. In our algorithm, we sample a "tempered" a posteriori PDF using many MCMC simulations running in parallel and evolutionary computation in which models which fit the data poorly are preferentially eliminated in favor of models which better predict the data. We present results for both synthetic test problems as well as for the 2007 Mw 7.8 Tocopilla, Chile earthquake, the latter of which is constrained by InSAR, local high

  17. [Subarachnoid hematoma and spinal anesthesia].

    PubMed

    Dupeyrat, A; Dequiré, P M; Mérouani, A; Moullier, P; Eid, G

    1990-01-01

    Two cases of spinal subarachnoid haematoma occurring after spinal anaesthesia are reported. In the first case, lumbar puncture was attempted three times in a 81-year-old man; spinal anaesthesia trial was than abandoned, and the patient given a general anaesthetic. He was given prophylactic calcium heparinate soon after surgery. On the fourth day, the patient became paraparetic. Radioculography revealed a blockage between T10 and L3. Laminectomy was performed to remove the haematoma, but the patient recovered motor activity only very partially. The second case was a 67-year-old man, in whom spinal anaesthesia was easily carried out. He was also given prophylactic calcium heparinate soon after surgery. On the fourth postoperative day, pulmonary embolism was suspected. Heparin treatment was then started. Twelve hours later, lumbar and bilateral buttock pain occurred, which later spread to the neck. On the eighth day, the patient had neck stiffness and two seizures. Emergency laminectomy was carried out, which revealed a subarachnoid haematoma spreading to a level higher than T6 and below L1, with no flow of cerebrospinal fluid, and a non pulsatile spinal cord. Surgery was stopped. The patient died on the following day. Both these cases are similar to those previously reported and point out the role played by anticoagulants. Because early diagnosis of spinal cord compression is difficult, the prognosis is poor, especially in case of paraplegia. PMID:2278424

  18. Neurotrophins and spinal circuit function

    PubMed Central

    Boyce, Vanessa S.; Mendell, Lorne M.

    2014-01-01

    Work early in the last century emphasized the stereotyped activity of spinal circuits based on studies of reflexes. However, the last several decades have focused on the plasticity of these spinal circuits. These considerations began with studies of the effects of monoamines on descending and reflex circuits. In recent years new classes of compounds called growth factors that are found in peripheral nerves and the spinal cord have been shown to affect circuit behavior in the spinal cord. In this review we will focus on the effects of neurotrophins, particularly nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), on spinal circuits. We also discuss evidence that these molecules can modify functions including nociceptive behavior, motor reflexes and stepping behavior. Since these substances and their receptors are normally present in the spinal cord, they could potentially be useful in improving function in disease states and after injury. Here we review recent findings relevant to these translational issues. PMID:24926235

  19. Adjacent level disease following lumbar spine surgery: A review

    PubMed Central

    Epstein, Nancy E.

    2015-01-01

    Background: Instrumented lumbar spine surgery is associated with an increased risk of adjacent segment disease (ASD). Multiple studies have explored the various risk factors contributing to ASD that include; fusion length (especially, three or more levels), sagittal malalignment, facet injury, advanced age, and prior cephalad degenerative disease. Methods: In this selective review of ASD, following predominantly instrumented fusions for lumbar degenerative disease, patients typically underwent open versus minimally invasive surgery (MIS), transforaminal lumbar interbody fusions (TLIFs), posterior lumbar interbody fusions (PLIFs), or rarely posterolateral lumbar instrumented or noninstrumented fusions (posterolateral lumbar fusion). Results: The incidence of ASD, following open or MI lumbar instrumented fusions, ranged up to 30%; notably, the addition of instrumentation in different series did not correlate with improved outcomes. Alternatively, in one series, at 164 postoperative months, noninstrumented lumbar fusions reduced the incidence of ASD to 5.6% versus 18.5% for ASD performed with instrumentation. Of interest, dynamic instrumented/stabilization techniques did not protect patients from ASD. Furthermore, in a series of 513 MIS TLIF, there was a 15.6% incidence of perioperative complications that included; a 5.1% frequency of durotomy and a 2.3% instrumentation failure rate. Conclusions: The incidence of postoperative ASD (up to 30%) is greater following either open or MIS instrumented lumbar fusions (e.g., TLIF/PLIF), while decompressions with noninstrumented fusions led to a much smaller 5.6% risk of ASD. Other findings included: MIS instrumented fusions contributed to higher perioperative complication rates, and dynamic stabilization did not protect against ASD. PMID:26693387

  20. Pathophysiology of primary spinal syringomyelia

    PubMed Central

    Heiss, John D.; Snyder, Kendall; Peterson, Matthew M.; Patronas, Nicholas J.; Butman, John A.; Smith, René K.; DeVroom, Hetty L.; Sansur, Charles A.; Eskioglu, Eric; Kammerer, William A.; Oldfield, Edward H.

    2013-01-01

    Object The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression. Methods To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing. Results In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure

  1. Kinematic hardening in creep of Zircaloy

    NASA Astrophysics Data System (ADS)

    Sedláček, Radan; Deuble, Dietmar

    2016-10-01

    Results of biaxial creep tests with stress changes on Zircaloy-2 tube samples are presented. A Hollomon-type viscoplastic strain hardening model is extended by the Armstrong-Frederic nonlinear kinematic hardening law, resulting in a mixed (i.e. isotropic and kinematic) strain hardening model. The creep tests with stress changes and similar tests published in the literature are simulated by the models. It is shown that introduction of the kinematic strain hardening in the viscoplastic strain hardening model is sufficient to describe the creep transients following stress drops, stress reversals and stress removals.

  2. Spinal, pelvic, and hip movement asymmetries in people with lower-limb amputation: Systematic review.

    PubMed

    Devan, Hemakumar; Carman, Allan; Hendrick, Paul; Hale, Leigh; Ribeiro, Daniel Cury

    2015-01-01

    Following amputation, people with transfemoral amputation (TFA) and transtibial amputation (TTA) adapt with asymmetrical movements in the spinal and lower-limb joints. The aim of this review is to describe the trunk, lumbopelvic, and hip joint movement asymmetries of the amputated limb of people with TFA and TTA during functional tasks as compared with the intact leg and/or referent leg of nondisabled controls. Electronic databases were searched from inception to February 2014. Studies with kinematic data comparing (1) amputated and intact leg and (2) amputated and referent leg of nondisabled controls were included (26 articles). Considerable heterogeneity in the studies precluded data pooling. During stance phase of walking in participants with TFA, there is moderate evidence for increased trunk lateral flexion toward the amputated limb as compared with the intact leg and increased anterior pelvic tilt as compared with nondisabled controls. None of the studies investigated spinal kinematics during other functional tasks such as running, ramp walking, stair climbing, or obstacle crossing in participants with TFA or TTA. Overall, persons with TFA adapt with trunk and pelvic movement asymmetries at the amputated limb to facilitate weight transfer during walking. Among participants with TTA, there is limited evidence of spinal and pelvic asymmetries during walking.

  3. Hindlimb Stretching Alters Locomotor Function Post-Spinal Cord Injury in the Adult Rat

    PubMed Central

    Caudle, Krista L.; Atkinson, Darryn A.; Brown, Edward H.; Donaldson, Katie; Seibt, Erik; Chea, Tim; Smith, Erin; Chung, Karianne; Shum-Siu, Alice; Cron, Courtney C.; Magnuson, David S. K.

    2014-01-01

    Background Stretching is a widely accepted standard-of-care therapy following spinal cord injury that has not been systematically studied in animal models. Objective To investigate the influence of a daily stretch-based physical therapy program on locomotor recovery in adult rats with moderate T9 contusive SCI. Methods A randomized treatment and control study of stretching in an animal model of acute spinal cord injury (SCI). Moderate spinal cord injuries were delivered with the NYU Impactor. Daily stretching (30 min./day, 5 days/wk for 8 wks) was provided by a team of animal handlers. Hindlimb function was assessed using the BBB Open Field Locomotor Scale and kinematically. Passive range-of-motion for each joint was determined weekly using a goniometer. Results Declines in hindlimb function during overground stepping were observed for the first 4 weeks. BBB scores improved weeks 5–10 but remained below the control group. Stretched animals had significant deficits in knee passive ROM starting at week 4 and for the duration of the study. Kinematic assessment showed decreased joint excursion during stepping that partially recovered beginning at week 5. Conclusion Stretch-based therapy significantly impaired functional recovery in adult rats with a moderate contusive SCI at T10. The negative impact on function was greatest acutely, but persisted even after the stretching ceased at 8 weeks post-injury. PMID:25106555

  4. Spinal, pelvic, and hip movement asymmetries in people with lower-limb amputation: Systematic review.

    PubMed

    Devan, Hemakumar; Carman, Allan; Hendrick, Paul; Hale, Leigh; Ribeiro, Daniel Cury

    2015-01-01

    Following amputation, people with transfemoral amputation (TFA) and transtibial amputation (TTA) adapt with asymmetrical movements in the spinal and lower-limb joints. The aim of this review is to describe the trunk, lumbopelvic, and hip joint movement asymmetries of the amputated limb of people with TFA and TTA during functional tasks as compared with the intact leg and/or referent leg of nondisabled controls. Electronic databases were searched from inception to February 2014. Studies with kinematic data comparing (1) amputated and intact leg and (2) amputated and referent leg of nondisabled controls were included (26 articles). Considerable heterogeneity in the studies precluded data pooling. During stance phase of walking in participants with TFA, there is moderate evidence for increased trunk lateral flexion toward the amputated limb as compared with the intact leg and increased anterior pelvic tilt as compared with nondisabled controls. None of the studies investigated spinal kinematics during other functional tasks such as running, ramp walking, stair climbing, or obstacle crossing in participants with TFA or TTA. Overall, persons with TFA adapt with trunk and pelvic movement asymmetries at the amputated limb to facilitate weight transfer during walking. Among participants with TTA, there is limited evidence of spinal and pelvic asymmetries during walking. PMID:26186283

  5. Carpal kinematics of lunotriquetral dissociations.

    PubMed

    Li, G; Rowen, B; Tokunaga, D; Ryu, J; Kato, H; Kihira, M

    1991-01-01

    The purpose of this study is to investigate the carpal kinematics after serial arthroscopic sectioning of the ligaments at the lunotriquetral joint, without damaging the capsule and other soft tissues of the wrist. Six cadaver wrists were studied and a custom designed three-dimensional mechanical digitizer was utilized. Three sets of digitization were performed for a normal state, after arthroscopic sectioning of lunotriquetral interosseous ligament (stage A), and after further sectioning of volar radiolunotriquetral ligament (stage B). Motion of the scaphoid, lunate, triquetrum, capitate and hamate was studied. The results indicated that the motion of the triquetrum was significantly increased at stage A, particularly after 15 degrees of ulnar deviation. An increased motion at the lunotriquetral joint was observed at stage B, which was mainly due to the significantly decreased lunate extension motion and the increased triquetrum extension motion during wrist extension. This study suggested that the lunotriquetral interosseous ligament plays the most important role for the stabilization of the lunotriquetral joint during wrist ulnar deviation, while the volar radiolunotriquetral ligament may function as a stabilizer for the lunotriquetral joint during wrist extension. PMID:2065165

  6. Milky Way halo gas kinematics

    NASA Technical Reports Server (NTRS)

    Danly, L.

    1986-01-01

    Measurements of high resolution, short wavelength absorption data taken by IUE toward high latitude O and B stars are presented in a discussion of the large scale kinematic properties of Milky Way Halo gas. An analysis of these data demonstrates that: (1) the obsrved absorption widths (FWHM) of Si II are very large, ranging up to 150 Km/s for the most distant halo star; this is much larger than is generally appreciated from optical data; (2) the absorption is observed to be systematically negative in radial velocity, indicating that cool material is, on the whole, flowing toward the disk of the galaxy; (3) there is some evidence for asymmetry between the northern and southern galactic hemispheres, in accordance with the HI 21 cm data toward the galactic poles; (4) low column density gas with highly negative radial LSR velocity (V less than -70 km/s) can be found toward stars beyond 1-3 kpc in the northern galactic hemisphere in all four quadrants of galactic longitude; and (5) only the profiles toward stars in the direction of known high velocity HI features show a clear two component structure.

  7. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  8. Kinematics of sport wheelchair propulsion.

    PubMed

    Coutts, K D

    1990-01-01

    Eight international caliber wheelchair male athletes (3 basketball, 5 distance track) performed an all-out propulsion effort from a standing start for 10 seconds on a wheelchair ergometer. Comparisons between the basketball and track athletes on linear wheelchair and push rim velocity during the first 3 pushes and the peak value indicated that the basketball players had a significantly (p less than .05) higher push rim velocity throughout the effort and a higher wheelchair velocity only at the end of the first push. The track athletes attained a significantly higher peak wheelchair velocity. Graphical comparison of the best individual basketball and track athletes' performances indicated that the track athletes caught up to the basketball players after about 3.7 seconds or 12 meters and travelled 49 meters in the 10 seconds, compared to 37 meters for the basketball players. Differences in push rim and wheel diameter are considered the major factor in the noted differences in propulsion kinematics of basketball and track wheelchairs.

  9. Automated quantification of lumbar vertebral kinematics from dynamic fluoroscopic sequences

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Zhao, Kristin; Morel, Etienne; White, Dan; Magnuson, Dixon; Gay, Ralph; An, Kai-Nan; Robb, Richard

    2009-02-01

    We hypothesize that the vertebra-to-vertebra patterns of spinal flexion and extension motion of persons with lower back pain will differ from those of persons who are pain-free. Thus, it is our goal to measure the motion of individual lumbar vertebrae noninvasively from dynamic fluoroscopic sequences. Two-dimensional normalized mutual information-based image registration was used to track frame-to-frame motion. Software was developed that required the operator to identify each vertebra on the first frame of the sequence using a four-point "caliper" placed at the posterior and anterior edges of the inferior and superior end plates of the target vertebrae. The program then resolved the individual motions of each vertebra independently throughout the entire sequence. To validate the technique, 6 cadaveric lumbar spine specimens were potted in polymethylmethacrylate and instrumented with optoelectric sensors. The specimens were then placed in a custom dynamic spine simulator and moved through flexion-extension cycles while kinematic data and fluoroscopic sequences were simultaneously acquired. We found strong correlation between the absolute flexionextension range of motion of each vertebra as recorded by the optoelectric system and as determined from the fluoroscopic sequence via registration. We conclude that this method is a viable way of noninvasively assessing twodimensional vertebral motion.

  10. Genetics Home Reference: spinal muscular atrophy

    MedlinePlus

    ... a loss of specialized nerve cells, called motor neurons , in the spinal cord and the part of ... spinal cord ( the brainstem ). The loss of motor neurons leads to weakness and wasting ( atrophy ) of muscles ...

  11. Rehabilitation in spinal infection diseases.

    PubMed

    Nas, Kemal; Karakoç, Mehmet; Aydın, Abdulkadir; Öneş, Kadriye

    2015-01-18

    Spinal cord infections were the diseases defined by Hypocrite yet the absence of modern medicine and there was not a real protocol in rehabilitation although there were many aspects in surgical treatment options. The patients whether surgically or conservatively treated had a lot of neurological, motor, and sensory disturbances. Our clinic has quite experience from our previous researchs. Unfortunately, serious spinal cord infections are still present in our region. In these patients the basic rehabilitation approaches during early, pre-operation, post-operation period and in the home environment will provide significant contributions to improve the patients' sensory and motor skills, develop the balance and proriocaption, increase the independence of patients in daily living activities and minimize the assistance of other people. There is limited information in the literature related with the nature of the rehabilitation programmes to be applied for patients with spinal infections. The aim of this review is to share our clinic experience and summarise the publications about spinal infection rehabilitation. There are very few studies about the rehabilitation of spinal infections. There are still not enough studies about planning and performing rehabilitation programs in these patients. Therefore, a comprehensive rehabilitation programme during the hospitalisation and home periods is emphasised in order to provide optimal management and prevent further disability.

  12. Rehabilitation in spinal infection diseases

    PubMed Central

    Nas, Kemal; Karakoç, Mehmet; Aydın, Abdulkadir; Öneş, Kadriye

    2015-01-01

    Spinal cord infections were the diseases defined by Hypocrite yet the absence of modern medicine and there was not a real protocol in rehabilitation although there were many aspects in surgical treatment options. The patients whether surgically or conservatively treated had a lot of neurological, motor, and sensory disturbances. Our clinic has quite experience from our previous researchs. Unfortunately, serious spinal cord infections are still present in our region. In these patients the basic rehabilitation approaches during early, pre-operation, post-operation period and in the home environment will provide significant contributions to improve the patients’ sensory and motor skills, develop the balance and proriocaption, increase the independence of patients in daily living activities and minimize the assistance of other people. There is limited information in the literature related with the nature of the rehabilitation programmes to be applied for patients with spinal infections. The aim of this review is to share our clinic experience and summarise the publications about spinal infection rehabilitation. There are very few studies about the rehabilitation of spinal infections. There are still not enough studies about planning and performing rehabilitation programs in these patients. Therefore, a comprehensive rehabilitation programme during the hospitalisation and home periods is emphasised in order to provide optimal management and prevent further disability. PMID:25621205

  13. Ruptured Isolated Spinal Artery Aneurysms

    PubMed Central

    Gutierrez Romero, Diego; Batista, Andre Lima; Gentric, Jean Christoph; Raymond, Jean; Roy, Daniel; Weill, Alain

    2014-01-01

    Summary Isolated spinal artery aneurysms are exceedingly rare vascular lesions thought to be related to dissection of the arterial wall. We describe two cases presenting with spinal subarachnoid haemorrhage that underwent conservative management. In the first patient the radiculomedullary branch involved was feeding the anterior spinal artery at the level of D3 and thus, neither endovascular nor surgical approach was employed. Control angiography was performed at seven days and at three months, demonstrating complete resolution of the lesion. In our second case, neither the anterior spinal artery or the artery of Adamkiewicz could be identified during angiography, thus endovascular management was deemed contraindicated. Magnetic resonance imaging showed a stable lesion in the second patient. No rebleeding or other complications were seen. In comparison to intracranial aneurysms, spinal artery aneurysms tend to display a fusiform appearance and lack a clear neck in relation to the likely dissecting nature of the lesions. Due to the small number of cases reported, the natural history of these lesions is not well known making it difficult to establish the optimal treatment approach. Various management strategies may be supported, including surgical and endovascular treatment, but It would seem that a wait and see approach is also viable, with control angiogram and treatment decisions based on the evolution of the lesion. PMID:25496690

  14. Recurrence of spinal schwannoma: Is it preventable?

    PubMed Central

    Senapati, Satya B.; Mishra, Sudhansu S.; Dhir, Manmath K.; Patnaik, Ashis; Panigrahi, Souvagya

    2016-01-01

    Spinal schwannomas account for about 25% of primary intradural spinal cord tumors in adult. The prognosis for spinal schwannomas is excellent in most cases. Complete resection is curative. However following subtotal removal, recurrence develops after several years. We describe a case of recurrent spinal schwannoma who had been operated twice before for same disease. The possible cause of recurrence and difficulties in reoperation are discussed.

  15. Recurrence of spinal schwannoma: Is it preventable?

    PubMed Central

    Senapati, Satya B.; Mishra, Sudhansu S.; Dhir, Manmath K.; Patnaik, Ashis; Panigrahi, Souvagya

    2016-01-01

    Spinal schwannomas account for about 25% of primary intradural spinal cord tumors in adult. The prognosis for spinal schwannomas is excellent in most cases. Complete resection is curative. However following subtotal removal, recurrence develops after several years. We describe a case of recurrent spinal schwannoma who had been operated twice before for same disease. The possible cause of recurrence and difficulties in reoperation are discussed. PMID:27695564

  16. Spinal angiolipoma with acute subarachnoid hemorrhage.

    PubMed

    Raghavendra, S; Krishnamoorthy, T; Ashalatha, R; Kesavadas, C

    2007-10-01

    Angiolipoma is a rare tumor of the spine commonly presenting with compressive myelopathy. We report a spinal angiolipoma in a 14-year-old patient with acute spinal subarachnoid hemorrhage (SAH). To our knowledge this is the first reported case of a spinal angiolipoma presenting with SAH, associated with post-subclavian coarctation with diffuse hypoplasia of the descending aorta. This association of coarctation of aorta, aortic hypoplasia and spinal angiolipoma has also not been reported previously.

  17. Non-equilibrium Kinematics in Merging Galaxies

    NASA Astrophysics Data System (ADS)

    Mihos, J. C.

    Measurements of the kinematics of merging galaxies are often used to derive dynamical masses, study evolution onto the fundamental plane, or probe relaxation processes. These measurements are often compromised to some degree by strong non-equilibrium motions in the merging galaxies. This talk focuses on the evolution of the kinematics of merging galaxies, and highlights some pitfalls which occur when studying non-equilibrium systems.

  18. Swimming as a Model of Task-Specific Locomotor Retraining After Spinal Cord Injury in the Rat

    PubMed Central

    Magnuson, David S. K.; Smith, Rebecca R.; Brown, Edward H.; Enzmann, Gaby; Angeli, Claudia; Quesada, Peter M.; Burke, Darlene

    2010-01-01

    Background The authors have shown that rats can be retrained to swim after a moderately severe thoracic spinal cord contusion. They also found that improvements in body position and hindlimb activity occurred rapidly over the first 2 weeks of training, reaching a plateau by week 4. Overground walking was not influenced by swim training, suggesting that swimming may be a task-specific model of locomotor retraining. Objective To provide a quantitative description of hindlimb movements of uninjured adult rats during swimming, and then after injury and retraining. Methods The authors used a novel and streamlined kinematic assessment of swimming in which each limb is described in 2 dimensions, as 3 segments and 2 angles. Results The kinematics of uninjured rats do not change over 4 weeks of daily swimming, suggesting that acclimatization does not involve refinements in hindlimb movement. After spinal cord injury, retraining involved increases in hindlimb excursion and improved limb position, but the velocity of the movements remained slow. Conclusion These data suggest that the activity pattern of swimming is hardwired in the rat spinal cord. After spinal cord injury, repetition is sufficient to bring about significant improvements in the pattern of hindlimb movement but does not improve the forces generated, leaving the animals with persistent deficits. These data support the concept that force (load) and pattern generation (recruitment) are independent and may have to be managed together with respect to postinjury rehabilitation. PMID:19270266

  19. Evaluation of spinal cord injury animal models

    PubMed Central

    Zhang, Ning; Fang, Marong; Chen, Haohao; Gou, Fangming; Ding, Mingxing

    2014-01-01

    Because there is no curative treatment for spinal cord injury, establishing an ideal animal model is important to identify injury mechanisms and develop therapies for individuals suffering from spinal cord injuries. In this article, we systematically review and analyze various kinds of animal models of spinal cord injury and assess their advantages and disadvantages for further studies. PMID:25598784

  20. Four cases of spinal epidural angiolipoma.

    PubMed

    Sim, Kenneth; Tsui, Alpha; Paldor, Iddo; Kaye, Andrew H; Gaillard, Frank

    2016-03-01

    Spinal angiolipomas are uncommon benign tumours composed of mature fatty tissue and abnormal vascular elements, most commonly found within the posterior spinal epidural space. Most tumours are located within the mid-thoracic spine; in contrast thoracolumbar junction and purely lumbar angiolipomas are rare. We report a case series of four spinal angiolipomas, including a thoracolumbar junction and a purely lumbar tumour.

  1. Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation.

    PubMed

    Cortés, Camilo; de Los Reyes-Guzmán, Ana; Scorza, Davide; Bertelsen, Álvaro; Carrasco, Eduardo; Gil-Agudo, Ángel; Ruiz-Salguero, Oscar; Flórez, Julián

    2016-01-01

    Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury). The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement. The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton. This approximation is rough since their kinematic structures differ. Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup. Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains. EIKPE has been tested with single DOF movements of the wrist and elbow joints. This paper presents the assessment of EIKPE with elbow-shoulder compound movements (i.e., object prehension). Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage). The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compound movement execution, especially for the shoulder joint angles. This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types. PMID:27403420

  2. Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation.

    PubMed

    Cortés, Camilo; de Los Reyes-Guzmán, Ana; Scorza, Davide; Bertelsen, Álvaro; Carrasco, Eduardo; Gil-Agudo, Ángel; Ruiz-Salguero, Oscar; Flórez, Julián

    2016-01-01

    Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury). The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement. The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton. This approximation is rough since their kinematic structures differ. Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup. Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains. EIKPE has been tested with single DOF movements of the wrist and elbow joints. This paper presents the assessment of EIKPE with elbow-shoulder compound movements (i.e., object prehension). Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage). The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compound movement execution, especially for the shoulder joint angles. This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types.

  3. Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation

    PubMed Central

    Cortés, Camilo; de los Reyes-Guzmán, Ana; Scorza, Davide; Bertelsen, Álvaro; Carrasco, Eduardo; Gil-Agudo, Ángel; Ruiz-Salguero, Oscar; Flórez, Julián

    2016-01-01

    Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury). The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement. The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton. This approximation is rough since their kinematic structures differ. Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup. Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains. EIKPE has been tested with single DOF movements of the wrist and elbow joints. This paper presents the assessment of EIKPE with elbow-shoulder compound movements (i.e., object prehension). Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage). The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compound movement execution, especially for the shoulder joint angles. This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types. PMID:27403420

  4. Spinal reflexes in brain death.

    PubMed

    Beckmann, Yesim; Çiftçi, Yeliz; Incesu, Tülay Kurt; Seçil, Yaprak; Akhan, Galip

    2014-12-01

    Spontaneous and reflex movements have been described in brain death and these unusual movements might cause uncertainties in diagnosis. In this study we evaluated the presence of spinal reflexes in patients who fulfilled the criteria for brain death. Thirty-two (22 %) of 144 patients presented unexpected motor movements spontaneously or during examinations. These patients exhibited the following signs: undulating toe, increased deep tendon reflexes, plantar responses, Lazarus sign, flexion-withdrawal reflex, facial myokymia, neck-arm flexion, finger jerks and fasciculations. In comparison, there were no significant differences in age, sex, etiology of brain death and hemodynamic laboratory findings in patients with and without reflex motor movement. Spinal reflexes should be well recognized by physicians and it should be born in mind that brain death can be determined in the presence of spinal reflexes.

  5. Modal kinematics for multisection continuum arms.

    PubMed

    Godage, Isuru S; Medrano-Cerda, Gustavo A; Branson, David T; Guglielmino, Emanuele; Caldwell, Darwin G

    2015-05-13

    This paper presents a novel spatial kinematic model for multisection continuum arms based on mode shape functions (MSF). Modal methods have been used in many disciplines from finite element methods to structural analysis to approximate complex and nonlinear parametric variations with simple mathematical functions. Given certain constraints and required accuracy, this helps to simplify complex phenomena with numerically efficient implementations leading to fast computations. A successful application of the modal approximation techniques to develop a new modal kinematic model for general variable length multisection continuum arms is discussed. The proposed method solves the limitations associated with previous models and introduces a new approach for readily deriving exact, singularity-free and unique MSF's that simplifies the approach and avoids mode switching. The model is able to simulate spatial bending as well as straight arm motions (i.e., pure elongation/contraction), and introduces inverse position and orientation kinematics for multisection continuum arms. A kinematic decoupling feature, splitting position and orientation inverse kinematics is introduced. This type of decoupling has not been presented for these types of robotic arms before. The model also carefully accounts for physical constraints in the joint space to provide enhanced insight into practical mechanics and impose actuator mechanical limitations onto the kinematics thus generating fully realizable results. The proposed method is easily applicable to a broad spectrum of continuum arm designs.

  6. Modal kinematics for multisection continuum arms.

    PubMed

    Godage, Isuru S; Medrano-Cerda, Gustavo A; Branson, David T; Guglielmino, Emanuele; Caldwell, Darwin G

    2015-06-01

    This paper presents a novel spatial kinematic model for multisection continuum arms based on mode shape functions (MSF). Modal methods have been used in many disciplines from finite element methods to structural analysis to approximate complex and nonlinear parametric variations with simple mathematical functions. Given certain constraints and required accuracy, this helps to simplify complex phenomena with numerically efficient implementations leading to fast computations. A successful application of the modal approximation techniques to develop a new modal kinematic model for general variable length multisection continuum arms is discussed. The proposed method solves the limitations associated with previous models and introduces a new approach for readily deriving exact, singularity-free and unique MSF's that simplifies the approach and avoids mode switching. The model is able to simulate spatial bending as well as straight arm motions (i.e., pure elongation/contraction), and introduces inverse position and orientation kinematics for multisection continuum arms. A kinematic decoupling feature, splitting position and orientation inverse kinematics is introduced. This type of decoupling has not been presented for these types of robotic arms before. The model also carefully accounts for physical constraints in the joint space to provide enhanced insight into practical mechanics and impose actuator mechanical limitations onto the kinematics thus generating fully realizable results. The proposed method is easily applicable to a broad spectrum of continuum arm designs. PMID:25969947

  7. Lumbar spinal loads and muscle activity during a golf swing.

    PubMed

    Lim, Young-Tae; Chow, John W; Chae, Woen-Sik

    2012-06-01

    This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads. PMID:22900401

  8. Spinal injuries in contact sports.

    PubMed

    Wilson, Joseph B; Zarzour, Robert; Moorman, Claude T

    2006-02-01

    Contact and collision sports such as American football expose the athlete to a wide array of potential injuries. Knee injuries garner much of the attention, but spinal injuries are potentially catastrophic and all levels of medical coverage of football must be knowledgeable and prepared to attend to an athlete with a neck injury. Of the other possible spinal conditions, some resolve on their own, others might require conservative therapy, and still others might require surgical intervention. The spectrum of potential injury is wide, yet the medical team must practice and prepare to treat the possible catastrophic neck injury.

  9. Management of Chronic Spinal Cord Dysfunction

    PubMed Central

    Abrams, Gary M.; Ganguly, Karunesh

    2015-01-01

    Purpose of Review: Both acute and chronic spinal cord disorders present multisystem management problems to the clinician. This article highlights key issues associated with chronic spinal cord dysfunction. Recent Findings: Advances in symptomatic management for chronic spinal cord dysfunction include use of botulinum toxin to manage detrusor hyperreflexia, pregabalin for management of neuropathic pain, and intensive locomotor training for improved walking ability in incomplete spinal cord injuries. Summary: The care of spinal cord dysfunction has advanced significantly over the past 2 decades. Management and treatment of neurologic and non-neurologic complications of chronic myelopathies ensure that each patient will be able to maximize their functional independence and quality of life. PMID:25651225

  10. The correlation between movement of the center of mass and the kinematics of the spine, pelvis, and hip joints during body rotation.

    PubMed

    Wada, Osamu; Tateuchi, Hiroshige; Ichihashi, Noriaki

    2014-01-01

    Body rotation is associated with many activities. The concomitant movement of the center of mass (COM) is essential for effective body rotation. This movement is considered to be influenced by kinematic changes in the spine, pelvis, and hip joints. However, there is no research on the association between COM movement and kinematic changes during body rotation. We aimed to investigate the association between COM movement and the kinematics of the spine, pelvis, and hip joints during body rotation in standing. Twenty-four healthy men were included in the study. COM movement during active body rotation in a standing position was measured. We evaluated pelvic shift and changes in the angles of the spine, pelvis, and hip joints. We calculated the Pearson correlation coefficients to analyze the relationship between COM movement and kinematic changes in the spine, pelvis, and hip joints. There were significant correlations between lateral COM movement to the rotational side and pelvic shift to the rotational side, and between posterior COM movement and pelvic shift to the posterior side. In addition, lateral COM movement to the rotational side showed significant and negative correlation with spinal flexion and was significantly and positively correlated with the change in anterior pelvic tilt. Clinicians need to take particular note of both spinal and pelvic motion in the sagittal plane, as well as the pelvic shift, to speculate COM movement during body rotation in standing.

  11. Adaptive muscle plasticity of a remaining agonist following denervation of its close synergists in a model of complete spinal cord injury.

    PubMed

    Dambreville, Charline; Charest, Jérémie; Thibaudier, Yann; Hurteau, Marie-France; Kuczynski, Victoria; Grenier, Guillaume; Frigon, Alain

    2016-09-01

    Complete spinal cord injury (SCI) alters the contractile properties of skeletal muscle, and although exercise can induce positive changes, it is unclear whether the remaining motor system can produce adaptive muscle plasticity in response to a subsequent peripheral nerve injury. To address this, the nerve supplying the lateral gastrocnemius (LG) and soleus muscles was sectioned unilaterally in four cats that had recovered hindlimb locomotion after spinal transection. In these spinal cats, kinematics and electromyography (EMG) were collected before and for 8 wk after denervation. Muscle histology was performed on LG and medial gastrocnemius (MG) bilaterally in four spinal and four intact cats. In spinal cats, cycle duration for the hindlimb ipsilateral or contralateral to the denervation could be significantly increased or decreased compared with predenervation values. Stance duration was generally increased and decreased for the contralateral and ipsilateral hindlimbs, respectively. The EMG amplitude of MG was significantly increased bilaterally after denervation and remained elevated 8 wk after denervation. In spinal cats the ipsilateral LG was significantly smaller than the contralateral LG, whereas the ipsilateral MG weighed significantly more than the contralateral MG. Histological characterizations revealed significantly larger fiber areas for type IIa fibers of the ipsilateral MG in three of four spinal cats. Microvascular density in the ipsilateral MG was significantly higher than in the contralateral MG. In intact cats, no differences were found for muscle weight, fiber area, or microvascular density between homologous muscles. Therefore, the remaining motor system after complete SCI retains the ability to produce adaptive muscle plasticity.

  12. Adaptive muscle plasticity of a remaining agonist following denervation of its close synergists in a model of complete spinal cord injury.

    PubMed

    Dambreville, Charline; Charest, Jérémie; Thibaudier, Yann; Hurteau, Marie-France; Kuczynski, Victoria; Grenier, Guillaume; Frigon, Alain

    2016-09-01

    Complete spinal cord injury (SCI) alters the contractile properties of skeletal muscle, and although exercise can induce positive changes, it is unclear whether the remaining motor system can produce adaptive muscle plasticity in response to a subsequent peripheral nerve injury. To address this, the nerve supplying the lateral gastrocnemius (LG) and soleus muscles was sectioned unilaterally in four cats that had recovered hindlimb locomotion after spinal transection. In these spinal cats, kinematics and electromyography (EMG) were collected before and for 8 wk after denervation. Muscle histology was performed on LG and medial gastrocnemius (MG) bilaterally in four spinal and four intact cats. In spinal cats, cycle duration for the hindlimb ipsilateral or contralateral to the denervation could be significantly increased or decreased compared with predenervation values. Stance duration was generally increased and decreased for the contralateral and ipsilateral hindlimbs, respectively. The EMG amplitude of MG was significantly increased bilaterally after denervation and remained elevated 8 wk after denervation. In spinal cats the ipsilateral LG was significantly smaller than the contralateral LG, whereas the ipsilateral MG weighed significantly more than the contralateral MG. Histological characterizations revealed significantly larger fiber areas for type IIa fibers of the ipsilateral MG in three of four spinal cats. Microvascular density in the ipsilateral MG was significantly higher than in the contralateral MG. In intact cats, no differences were found for muscle weight, fiber area, or microvascular density between homologous muscles. Therefore, the remaining motor system after complete SCI retains the ability to produce adaptive muscle plasticity. PMID:27358318

  13. Investigation of impact loading rate effects on the ligamentous cervical spinal load-partitioning using finite element model of functional spinal unit C2-C3.

    PubMed

    Mustafy, Tanvir; El-Rich, Marwan; Mesfar, Wissal; Moglo, Kodjo

    2014-09-22

    The cervical spine functions as a complex mechanism that responds to sudden loading in a unique manner, due to intricate structural features and kinematics. The spinal load-sharing under pure compression and sagittal flexion/extension at two different impact rates were compared using a bio-fidelic finite element (FE) model of the ligamentous cervical functional spinal unit (FSU) C2-C3. This model was developed using a comprehensive and realistic geometry of spinal components and material laws that include strain rate dependency, bone fracture, and ligament failure. The range of motion, contact pressure in facet joints, failure forces in ligaments were compared to experimental findings. The model demonstrated that resistance of spinal components to impact load is dependent on loading rate and direction. For the loads applied, stress increased with loading rate in all spinal components, and was concentrated in the outer intervertebral disc (IVD), regions of ligaments to bone attachment, and in the cancellous bone of the facet joints. The highest stress in ligaments was found in capsular ligament (CL) in all cases. Intradiscal pressure (IDP) in the nucleus was affected by loading rate change. It increased under compression/flexion but decreased under extension. Contact pressure in the facet joints showed less variation under compression, but increased significantly under flexion/extension particularly under extension. Cancellous bone of the facet joints region was the only component fractured and fracture occurred under extension at both rates. The cervical ligaments were the primary load-bearing component followed by the IVD, endplates and cancellous bone; however, the latter was the most vulnerable to extension as it fractured at low energy impact.

  14. Vestibulo-spinal reflex mechanisms

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.

    1981-01-01

    The specific objectives of experiments designed to investigate postural reflex behavior during sustained weightlessness are discussed. The first is to investigate, during prolonged weightlessness with Hoffmann response (H-reflex) measurement procedures, vestibulo-spinal reflexes associated with vestibular (otolith) responses evoked during an applied linear acceleration. This objective includes not only an evaluation of otolith-induced changes in a major postural muscle but also an investigation with this technique of the adaptive process of the vestibular system and spinal reflex mechanisms to this unique environment. The second objective is to relate space motion sickness to the results of this investigation. Finally, a return to the vestibulo-spinal and postural reflexes to normal values following the flight will be examined. The flight experiment involves activation of nerve tissue (tibial N) with electrical shock and the recording of resulting muscle activity (soleus) with surface electrodes. Soleus/spinal H-reflex testing procedures will be used in conjuction with linear acceleration through the subject's X-axis.

  15. Biomechanics of Degenerative Spinal Disorders

    PubMed Central

    Iorio, Justin A.; Jakoi, Andre M.

    2016-01-01

    The spine has several important functions including load transmission, permission of limited motion, and protection of the spinal cord. The vertebrae form functional spinal units, which represent the smallest segment that has characteristics of the entire spinal column. Discs and paired facet joints within each functional unit form a three-joint complex between which loads are transmitted. Surrounding the spinal motion segment are ligaments, composed of elastin and collagen, and joint capsules which restrict motion to within normal limits. Ligaments have variable strengths and act via different lever arm lengths to contribute to spinal stability. As a consequence of the longer moment arm from the spinous process to the instantaneous axis of rotation, inherently weaker ligaments (interspinous and supraspinous) are able to provide resistance to excessive flexion. Degenerative processes of the spine are a normal result of aging and occur on a spectrum. During the second decade of life, the intervertebral disc demonstrates histologic evidence of nucleus pulposus degradation caused by reduced end plate blood supply. As disc height decreases, the functional unit is capable of an increased range of axial rotation which subjects the posterior facet capsules to greater mechanical loads. A concurrent change in load transmission across the end plates and translation of the instantaneous axis of rotation further increase the degenerative processes at adjacent structures. The behavior of the functional unit is impacted by these processes and is reflected by changes in the stress-strain relationship. Back pain and other clinical symptoms may occur as a result of the biomechanical alterations of degeneration. PMID:27114783

  16. Management of lumbar spinal stenosis.

    PubMed

    Lurie, Jon; Tomkins-Lane, Christy

    2016-01-01

    Lumbar spinal stenosis (LSS) affects more than 200,000 adults in the United States, resulting in substantial pain and disability. It is the most common reason for spinal surgery in patients over 65 years. Lumbar spinal stenosis is a clinical syndrome of pain in the buttocks or lower extremities, with or without back pain. It is associated with reduced space available for the neural and vascular elements of the lumbar spine. The condition is often exacerbated by standing, walking, or lumbar extension and relieved by forward flexion, sitting, or recumbency. Clinical care and research into lumbar spinal stenosis is complicated by the heterogeneity of the condition, the lack of standard criteria for diagnosis and inclusion in studies, and high rates of anatomic stenosis on imaging studies in older people who are completely asymptomatic. The options for non-surgical management include drugs, physiotherapy, spinal injections, lifestyle modification, and multidisciplinary rehabilitation. However, few high quality randomized trials have looked at conservative management. A systematic review concluded that there is insufficient evidence to recommend any specific type of non-surgical treatment. Several different surgical procedures are used to treat patients who do not improve with non-operative therapies. Given that rapid deterioration is rare and that symptoms often wax and wane or gradually improve, surgery is almost always elective and considered only if sufficiently bothersome symptoms persist despite trials of less invasive interventions. Outcomes (leg pain and disability) seem to be better for surgery than for non-operative treatment, but the evidence is heterogeneous and often of limited quality. PMID:26727925

  17. KINEMATIC AND SPATIAL SUBSTRUCTURE IN NGC 2264

    SciTech Connect

    Tobin, John J.; Hartmann, Lee; Hsu, Wen-Hsin; Mateo, Mario; Fűrész, Gabor

    2015-04-15

    We present an expanded kinematic study of the young cluster NGC 2264 based upon optical radial velocities measured using multi-fiber echelle spectroscopy at the 6.5 m MMT and Magellan telescopes. We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Fűrész et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas. In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular ({sup 13}CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon. Our results emphasize the complexity of the spatial and kinematic structure of NGC 2264, important for eventually building up a comprehensive picture of cluster formation.

  18. Inverse kinematic-based robot control

    NASA Technical Reports Server (NTRS)

    Wolovich, W. A.; Flueckiger, K. F.

    1987-01-01

    A fundamental problem which must be resolved in virtually all non-trivial robotic operations is the well-known inverse kinematic question. More specifically, most of the tasks which robots are called upon to perform are specified in Cartesian (x,y,z) space, such as simple tracking along one or more straight line paths or following a specified surfacer with compliant force sensors and/or visual feedback. In all cases, control is actually implemented through coordinated motion of the various links which comprise the manipulator; i.e., in link space. As a consequence, the control computer of every sophisticated anthropomorphic robot must contain provisions for solving the inverse kinematic problem which, in the case of simple, non-redundant position control, involves the determination of the first three link angles, theta sub 1, theta sub 2, and theta sub 3, which produce a desired wrist origin position P sub xw, P sub yw, and P sub zw at the end of link 3 relative to some fixed base frame. Researchers outline a new inverse kinematic solution and demonstrate its potential via some recent computer simulations. They also compare it to current inverse kinematic methods and outline some of the remaining problems which will be addressed in order to render it fully operational. Also discussed are a number of practical consequences of this technique beyond its obvious use in solving the inverse kinematic question.

  19. Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study.

    PubMed

    Erbulut, Deniz U; Zafarparandeh, Iman; Hassan, Chaudhry R; Lazoglu, Ismail; Ozer, Ali F

    2015-08-01

    OBJECT The authors evaluated the biomechanical effects of an interspinous process (ISP) device on kinematics and load sharing at the implanted and adjacent segments. METHODS A 3D finite-element (FE) model of the lumbar spine (L1-5) was developed and validated through comparison with published in vitro study data. Specifically, validation was achieved by a flexible (load-control) approach in 3 main planes under a pure moment of 10 Nm and a compressive follower load of 400 N. The ISP device was inserted between the L-3 and L-4 processes. Intact and implanted cases were simulated using the hybrid protocol in all motion directions. The resultant motion, facet load, and intradiscal pressure after implantation were investigated at the index and adjacent levels. In addition, stress at the bone-implant interface was predicted. RESULTS The hybrid approach, shown to be appropriate for adjacent-level investigations, predicted that the ISP device would decrease the range of motion, facet load, and intradiscal pressure at the index level relative to the corresponding values for the intact spine in extension. Specifically, the intradiscal pressure induced after implantation at adjacent segments increased by 39.7% and by 6.6% at L2-3 and L4-5, respectively. Similarly, facet loads at adjacent segments after implantation increased up to 60% relative to the loads in the intact case. Further, the stress at the bone-implant interface increased significantly. The influence of the ISP device on load sharing parameters in motion directions other than extension was negligible. CONCLUSIONS Although ISP devices apply a distraction force on the processes and prevent further extension of the index segment, their implantation may cause changes in biomechanical parameters such as facet load, intradiscal pressure, and range of motion at adjacent levels in extension.

  20. [Iatrogenic spinal epidermoid tumors. A late complication of spinal puncture].

    PubMed

    Reina, M A; López-García, A; Dittmann, M; de Andrés, J A; Blázquez, M G

    1996-04-01

    INTRODUCTION. Epidermoid tumors in the spinal canal are rare. Whether congenitally or iatrogenically caused, they form as the result of epidermal cells implanted within the spinal channel. Such implantation can occur during a variety of procedures and events such as bullet wounds, surgery, myelography or punctures for diagnosis, anesthesia or treatment. Although this complication is not discussed in books or journals on anesthesiology, we have found it mentioned in over 100 published cases reporting iatrogenically caused spinal epidermoid tumors. ETIOPATHOGENESIS. Iatrogenic epidermoid tumors of the spine derive from the implantation of epidermal tissue transported inside the spinal canal during lumbar punctures without guidance or with inadequate guidance. There is ample evidence that such tumors are iatrogenic. All cases occur in patients with a history of lumbar puncture. They are rarely associated with congenital anomalies. They are extramedullary. They tend to develop near sites of earlier lumbar puncture, usually near the conus medullaris and the cauda equina. Iatrogenic epidermoid tumors of the spine have been reproduced experimentally in two studies in which autologous skin fragments were implanted in the spinal canal. CLINICAL SIGNS. These tumors are well tolerated by patients for extended periods of time, ranging from 2 to 10 years. At the cauda equinus, tumors can grow slowly for long periods without signs of nerve compression. Symptoms are directly related to tumor size and site. All patients with tumors at the cauda equinus report severe pain radiating toward the roots of compressed nerves. Nuclear magnetic resonance makes it possible to detect the tumor without administration of intrathecal contrast. At present gadolinium-DTPA improves the image so that these tumors can be distinguished from other types. The prognosis for epidermoid tumors of the spine is good, as they are histologically benign. Treatment is always surgical. CONCLUSION. Although the

  1. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    NASA Technical Reports Server (NTRS)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  2. Optimal pumping kinematics of a cilium

    NASA Astrophysics Data System (ADS)

    Eloy, Christophe; Lauga, Eric

    2012-11-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although the internal molecular structure of cilia has been remarkably conserved throughout evolution, experimental observations report qualitatively diverse kinematics in different species. To address this diversity, we have determined numerically the kinematics of the most efficient cilium. Specifically, we have computed the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost. Here, the energetic cost is taken to be the sum of positive works done by the internal torques, such that elastic energy is not conservative. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number Sp, and closely resemble the two-stroke ciliary beating pattern observed experimentally. We acknowledge supports from the EU (fellowship PIOF-GA-2009-252542 to C.E.) and the NSF (grant CBET-0746285 to E.L.).

  3. Numerical algebraic geometry and algebraic kinematics

    NASA Astrophysics Data System (ADS)

    Wampler, Charles W.; Sommese, Andrew J.

    In this article, the basic constructs of algebraic kinematics (links, joints, and mechanism spaces) are introduced. This provides a common schema for many kinds of problems that are of interest in kinematic studies. Once the problems are cast in this algebraic framework, they can be attacked by tools from algebraic geometry. In particular, we review the techniques of numerical algebraic geometry, which are primarily based on homotopy methods. We include a review of the main developments of recent years and outline some of the frontiers where further research is occurring. While numerical algebraic geometry applies broadly to any system of polynomial equations, algebraic kinematics provides a body of interesting examples for testing algorithms and for inspiring new avenues of work.

  4. Computer Assisted Mechanical Axis and Kinematic TKA

    PubMed Central

    McEwen, Peter; Mahoharan, Varaguna

    2016-01-01

    Introduction: Total knee arthroplasty (TKA) has traditionally been and largely continues to be aligned mechanically, that being with a neutral coronal plane mechanical tibiofemoral axis and a joint line orientated at 900 to this axis. Femoral component rotation is set by gap balancing or by externally rotating 30 from any of a number femoral reference lines. This produces a rectangular flexion gap and relaxes patellar tracking. Kinematic alignment (KA) is an alternative technique that aims to restore premorbid alignment, joint orientation and ligament tension. The basic premise for this technique is based on evidence that the medial and lateral femoral condyles consistently equate to cylinders of equal or near equal size and that therefore with a fixed radius, cruciate retaining implant, matched distal femoral, posterior femoral and proximal tibial resections, accounting for bone and cartilage already lost will reproduce the premorbid joint line and restore native premorbid kinematics. Femoral rotation is therefore referenced off the prearthritic posterior condylar axis (PCA) that is on average internally rotated to the AP axis. Kinematic alignment therefore has the potential to challenge patellar tracking, increase patellar load and potentially increase patellar complications. Method: Case control study – level of evidence III-2. Between November 2012 and June 2013 the senior author completed 104 consecutive computer assisted (CAS) kinematically aligned total knee arthroplasties (TKA) with a cruciate retaining, fixed bearing, single radius implant. The results of these surgeries were compared with the results of 91 consecutive CAS mechanically aligned TKA done between November 2011 and October 2012 using the same navigation system and implant Implant sizing and positioning as well as gap measurement and ligament balance was done with computer assistance in all cases. Data was collected prospectively and analysed retrospectively. Results: The Oxford Knee Score

  5. Highly damped kinematic coupling for precision instruments

    DOEpatents

    Hale, Layton C.; Jensen, Steven A.

    2001-01-01

    A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.

  6. Kinematics of the Most Efficient Cilium

    NASA Astrophysics Data System (ADS)

    Eloy, Christophe; Lauga, Eric

    2012-07-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although cilia have a remarkably conserved internal molecular structure, experimental observations report very diverse kinematics. To address this diversity, we determine numerically the kinematics and energetics of the most efficient cilium. Specifically, we compute the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost, where the cost is taken to be the positive work done by all internal molecular motors. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number, and closely resemble the two-stroke ciliary beating pattern observed experimentally.

  7. Dark energy as a kinematic effect

    NASA Astrophysics Data System (ADS)

    Jennen, H.; Pereira, J. G.

    2016-03-01

    We present a generalization of teleparallel gravity that is consistent with local spacetime kinematics regulated by the de Sitter group SO(1 , 4) . The mathematical structure of teleparallel gravity is shown to be given by a nonlinear Riemann-Cartan geometry without curvature, which inspires us to build the generalization on top of a de Sitter-Cartan geometry with a cosmological function. The cosmological function is given its own dynamics and naturally emerges nonminimally coupled to the gravitational field in a manner akin to teleparallel dark energy models or scalar-tensor theories in general relativity. New in the theory here presented, the cosmological function gives rise to a kinematic contribution in the deviation equation for the world lines of adjacent free-falling particles. While having its own dynamics, dark energy manifests itself in the local kinematics of spacetime.

  8. Temporal and kinematic consistency predict sequence awareness.

    PubMed

    Jaynes, Molly J; Schieber, Marc H; Mink, Jonathan W

    2016-10-01

    Many human motor skills can be represented as a hierarchical series of movement patterns. Awareness of underlying patterns can improve performance and decrease cognitive load. Subjects (n = 30) tapped a finger sequence with changing stimulus-to-response mapping and a common movement sequence. Thirteen subjects (43 %) became aware that they were tapping a familiar movement sequence during the experiment. Subjects who became aware of the underlying motor pattern tapped with greater kinematic and temporal consistency from task onset, but consistency was not sufficient for awareness. We found no effect of age, musical experience, tapping evenness, or inter-key-interval on awareness of the pattern in the motor response. We propose that temporal or kinematic consistency reinforces a pattern representation, but cognitive engagement with the contents of the sequence is necessary to bring the pattern to conscious awareness. These findings predict benefit for movement strategies that limit temporal and kinematic variability during motor learning. PMID:27324192

  9. Therapeutic approaches for spinal cord injury

    PubMed Central

    Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Marcon, Raphael Martus; Letaif, Olavo Biraghi; da Rocha, Ivan Dias

    2012-01-01

    This study reviews the literature concerning possible therapeutic approaches for spinal cord injury. Spinal cord injury is a disabling and irreversible condition that has high economic and social costs. There are both primary and secondary mechanisms of damage to the spinal cord. The primary lesion is the mechanical injury itself. The secondary lesion results from one or more biochemical and cellular processes that are triggered by the primary lesion. The frustration of health professionals in treating a severe spinal cord injury was described in 1700 BC in an Egyptian surgical papyrus that was translated by Edwin Smith; the papyrus reported spinal fractures as a “disease that should not be treated.” Over the last two decades, several studies have been performed to obtain more effective treatments for spinal cord injury. Most of these studies approach a patient with acute spinal cord injury in one of four manners: corrective surgery or a physical, biological or pharmacological treatment method. Science is unraveling the mechanisms of cell protection and neuroregeneration, but clinically, we only provide supportive care for patients with spinal cord injuries. By combining these treatments, researchers attempt to enhance the functional recovery of patients with spinal cord injuries. Advances in the last decade have allowed us to encourage the development of experimental studies in the field of spinal cord regeneration. The combination of several therapeutic strategies should, at minimum, allow for partial functional recoveries for these patients, which could improve their quality of life. PMID:23070351

  10. Kinematics and Control of Robot Manipulators

    NASA Astrophysics Data System (ADS)

    Paden, Bradley Evan

    This dissertation focuses on the kinematics and control of robot manipulators. The contribution to kinematics is a fundamental theorem on the design of manipulators with six revolute joints. The theorem states, roughly speaking, that manipulators which have six revolute joints and are modeled after the human arm are optimal and essentially unique. In developing the mathematical framework to prove this theorem, we define precisely the notions of length of a manipulator, well-connected-workspace, and work-volume. We contribute to control a set of analysis techniques for the design of variable structure (sliding mode) controllers for manipulators. The organization of the dissertation is the following. After introductory remarks in chapter one, the group of proper rigid motions, G, is introduced in chapter two. The tangent bundle of G is introduced and it is shown that the velocity of a rigid body can be represented by an element in the Lie algebra of G (commonly called a twist). Further, rigid motions which are exponentials of twists are used to describe four commonly occurring subproblems in robot kinematics. In chapter three, the exponentials of twists are used to write the forward kinematic map of robot manipulators and the subproblems of chapter two are used to solve the Stanford manipulator and an elbow manipulator. Chapter four focuses on manipulator singularities. Twist coordinates are used to find critical points of the forward kinematic map. The contribution to kinematics is contained in chapter five where a mathematical framework for studying the relationship between the design of 6R manipulators and their performance is developed. Chapter seven contains the contribution to control. The work of A. F. Filippov on differential equations with discontinuous right-hand-side and the work of F. H. Clarke on generalized gradients are combined to obtain a calculus for analyzing nonsmooth gradient systems. The techniques developed are applied to design a simple

  11. Human lumbosacral spinal cord interprets loading during stepping.

    PubMed

    Harkema, S J; Hurley, S L; Patel, U K; Requejo, P S; Dobkin, B H; Edgerton, V R

    1997-02-01

    Studies suggest that the human lumbosacral spinal cord can generate steplike oscillating electromyographic (EMG) patterns, but it remains unclear to what degree these efferent patterns depend on the phasic peripheral sensory information associated with bilateral limb movements and loading. We examined the role of sensory information related to lower-extremity weight bearing in modulating the efferent motor patterns of spinal-cord-injured (SCI) subjects during manually assisted stepping on a treadmill. Four nonambulatory subjects, each with a chronic thoracic spinal cord injury, and two nondisabled subjects were studied. The level of loading, EMG patterns, and kinematics of the lower limbs were studied during manually assisted or unassisted stepping on a treadmill with body weight support. The relationships among lumbosacral motor pool activity [soleus (SOL), medial gastrocnemius (MG), and tibialis anterior (TA)], limb load, muscle-tendon length, and velocity of muscle-tendon length change were examined. The EMG mean amplitude of the SOL, MG, and TA was directly related to the peak load per step on the lower limb during locomotion. The effects on the EMG amplitude were qualitatively similar in subjects with normal, partial, or no detectable supraspinal input. Responses were most consistent in the SOL and MG at load levels of < 50% of a subject's body weight. The modulation of the EMG amplitude from the SOL and MG, both across steps and within a step, was more closely associated with limb peak load than muscle-tendon stretch or the velocity of muscle-tendon stretch. Thus stretch reflexes were not the sole source of the phasic EMG activity in flexors and extensors during manually assisted stepping in SCI subjects. The EMG amplitude within a step was highly dependent on the phase of the step cycle regardless of level of load. These data suggest that level of loading on the lower limbs provides cues that enable the human lumbosacral spinal cord to modulate efferent

  12. Kinematic Distances of Galactic Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Yang, A. Y.; Tian, W. W.; Zhu, H.; Leahy, D. A.; Wu, D.

    2016-03-01

    We construct H i absorption spectra for 18 planetary nebulae (PNs) and their background sources using data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNs, among which 15 objects’ kinematic distances are obtained for the first time. The distance uncertainties of 13 PNs range from 10% to 50%, which is a significant improvement with uncertainties of a factor of two or three smaller than most previous distance measurements. We confirm that PN G030.2-00.1 is not a PN because of its large distance found here.

  13. Off-shell kinematics in nuclear processes

    NASA Astrophysics Data System (ADS)

    Thakur, Jagannath

    1983-11-01

    A semirelativistic model based on an approximate solution of the Bethe-Salpeter equation used previously to construct a conserved electromagnetic current with arbitrary interaction is generalized to arbitrary processes and extended to many body targets. Although the technique appears valid and useful for introducing kinematic corrections in processes off few body targets, a paradoxical result emerges for large nuclei in that the relevant form factors, which must be evaluated far off-shell, can be dramatically different from that for free nucleons, contrary to the usual picture of the nucleus as composed of nearly free nucleons. NUCLEAR REACTIONS Bethe-Salpeter equation, off-shell kinematics, impulse approximation, paradox for large nuclei.

  14. Calibration of parallel kinematic devices using sequential determination of kinematic parameters

    SciTech Connect

    JOKIEL JR.,BERNHARD; BIEG,LOTHAR F.; ZIEGERT,JOHN C.

    2000-04-06

    In PKM Machines, the Cartesian position and orientation of the tool point carried on the platform is obtained from a kinematic model of the particular machine. Accurate positioning of these machines relies on the accurate knowledge of the parameters of the kinematic model unique to the particular machine. The parameters in the kinematic model include the spatial locations of the joint centers on the machine base and moving platform, the initial strut lengths, and the strut displacements. The strut displacements are readily obtained from sensors on the machine. However, the remaining kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. The size and complexity of these machines generally makes it difficult and somewhat undesirable to determine the remaining kinematic parameters by direct inspection such as in a coordinate measuring machine. In order for PKMs to be useful for precision positioning applications, techniques must be developed to quickly calibrate the machine by determining the kinematic parameters without disassembly of the machine. A number of authors have reported techniques for calibration of PKMs (Soons, Masory, Zhuang et. al., Ropponen). In two other papers, the authors have reported on work recently completed by the University of Florida and Sandia National Laboratories on calibration of PKMs, which describes a new technique to sequentially determine the kinematic parameters of an assembled parallel kinematic device. The technique described is intended to be used with a spatial coordinate measuring device such as a portable articulated CMM measuring arm (Romer, Faro, etc.), a Laser Ball Bar (LBB), or a laser tracker (SMX< API, etc.). The material to be presented is as follows: (1) methods to identify the kinematic parameters of 6--6 variant Stewart platform manipulators including joint center locations relative to the workable and spindle nose

  15. Whole Spontaneous Spinal Epidural Hematoma

    PubMed Central

    Yoon, Kyeong-Wook; Song, Jae Gyok; Ryu, Jae-Wook

    2014-01-01

    A 26-year-old male who had no underlying disease, including coagulopathy, underwent thoracotomy and bleeding control due to hemothorax. On the fifth postoperative day, paralysis of both lower limbs occurred. Urgent spine magnetic resonance imaging showed a massive anterior spinal epidural hematoma from C2 to L1 level with different signal intensities, which was suspected to be staged hemorrhage. Hematoma evacuation with decompressive laminectomy was performed. The patient's neurologic deterioration was recovered immediately, and he was discharged without neurological deficits. A drug history of naftazone, which could induce a drug-induced platelet dysfunction, was revealed retrospectively. To our knowledge, this is the first report of whole spontaneous spinal epidural hematoma in a young patient, with a history of hemorrhoid medication. PMID:24967052

  16. Spontaneous Spinal Epidural Hematoma Report.

    PubMed

    Kukreja, Sunil; Nanda, Anil

    2016-01-01

    We report a case of spontaneous spinal epidural hematoma in a 12-year-old female, who presented with significant upper and lower extremities weakness preceded by pain around the neck and shoulder girdle. Magnetic resonance imaging revealed epidural hematoma extending from C6-T2 with characteristic heterogeneously hyperintensity on T2 and homogenously isointensity on T1. Emergent spinal decompression was performed. However, the patient remained substantially weak in her lower extremities and was wheelchair bound at 3 months postoperatively. We have discussed clinical features, predisposing events, pathogenesis and treatment guidelines described in the literature. We also aim to reinforce the notion of keeping a high degree of clinical suspicion to identify and intervene at the earliest stage to prevent the physically and socially challenging consequences of SSEH. PMID:27598898

  17. [Spinal stenosis: diagnosis and treatment].

    PubMed

    Faundez, Antonio; Genevay, Stéphane

    2012-06-27

    Spondylotic cervical myelopathy (SCM) is a radiologic entity that can match a clinical syndrome of varying degree of severity, and results from spinal canal narrowing due to physiological degeneration of the cervical spine. Clinically, cervical spinal canal narrowing can produce minimal symptoms such as non-specific neck pain, foraminal entrapment of nerve roots, or more severe, chronic myelopathy. SCM initially manifests by signs of posterior medullary tract dysfunction with subsequent pallesthesia, resulting in gait and balance disturbance. Spasticity due to lower motoneurone impairment and incontinence may appear in later stages. Once the symptoms of myelopathy occur, functional deterioration will take place sooner or later. Surgery can then be recommended and scheduled according to the severity of functional impairment and imaging.

  18. Ganglioglioma of the Spinal Cord

    PubMed Central

    Oppenheimer, Daniel C; Johnson, Mahlon D; Judkins, Alexander R

    2015-01-01

    Ganglioglioma is a rare tumor consisting of neoplastic glial and neuronal elements. It accounts for only 0.5% of all primary central nervous system (CNS) neoplasms. We report an unusual case of extensive intramedullary thoracic spinal cord ganglioglioma in a 14-month-old girl who underwent subtotal resection followed by adjuvant chemotherapy. The epidemiology, histopathologic features, imaging findings, treatment, and prognosis are subsequently reviewed. PMID:26605127

  19. How Are Brain and Spinal Cord Tumors in Children Diagnosed?

    MedlinePlus

    ... spinal cord tumors in children staged? How are brain and spinal cord tumors diagnosed in children? Brain ... resonance angiography (MRA) or computerized tomographic angiography (CTA). Brain or spinal cord tumor biopsy Imaging tests such ...

  20. Testosterone Plus Finasteride Treatment After Spinal Cord Injury

    ClinicalTrials.gov

    2016-07-07

    Spinal Cord Injury; Spinal Cord Injuries; Trauma, Nervous System; Wounds and Injuries; Central Nervous System Diseases; Nervous System Diseases; Spinal Cord Diseases; Gonadal Disorders; Endocrine System Diseases; Hypogonadism; Genital Diseases, Male

  1. Advances in Spinal Interbody Cages.

    PubMed

    Jain, Sukrit; Eltorai, Adam E M; Ruttiman, Roy; Daniels, Alan H

    2016-08-01

    Since the late 1980s, spinal interbody cages (ICs) have been used to aid bone fusion in a variety of spinal disorders. Utilized to restore intervertebral height, enable bone graft containment for arthrodesis, and restore anterior column biomechanical stability, ICs have since evolved to become a highly successful means of achieving fusion, being associated with less postoperative pain, shorter hospital stay, fewer complications and higher rates of fusion when than bone graft only spinal fusion. IC design and materials have changed considerably over the past two decades. The threaded titanium-alloy cylindrical screw cages, typically filled with autologous bone graft, of the mid-1990s achieved greater fusion rates than bone grafts and non-threaded cages. Threaded screw cages, however, were soon found to be less stable in extension and flexion; additionally, they had a high incidence of cage subsidence. As of the early 2000s, non-threaded box-shaped titanium or polyether ether ketone IC designs have become increasingly more common. This modern design continues to achieve greater cage stability in flexion, axial rotation and bending. However, cage stability and subsidence, bone fusion rates and surgical complications still require optimization. Thus, this review provides an update of recent research findings relevant to ICs over the past 3 years, highlighting trends in optimization of cage design, materials, alternatives to bone grafts, and coatings that may enhance fusion. PMID:27627709

  2. Postoperative posterior spinal wound infections.

    PubMed

    Massie, J B; Heller, J G; Abitbol, J J; McPherson, D; Garfin, S R

    1992-11-01

    The incidence of postoperative spinal infections increases with the complexity of the procedure. Diskectomy is associated with less than a 1% risk of infection; spinal fusion without instrumentation is associated with a 1%-5% risk; and fusion with instrumentation may be associated with a risk of 6% or more. Twenty-two postoperative posterior spinal infections that occurred during a three-year period were reviewed for this report. Staphylococcus aureus was the most frequent organism cultured (more than 50% of the cases). Other recurring organisms were Staphylococcus epidermis, Peptococcus, Enterobacter cloacae, and Bacteroides. Many patients had multiple organisms. Risk factors appeared to include advanced age, prolonged hospital bed rest, obesity, diabetes, immunosuppression, and infection at remote sites. Operative factors included prolonged surgery (greater than five hours), high volume of personnel moving through the operating room, and instrumentation. Postoperative contamination may occur and may be related to prolonged postoperative bed rest, skin maceration (thoracolumbosacral orthoses), and drainage tubes exiting distally from lumbar wounds (toward the rectum). Effective treatment includes early diagnosis, surgical debridement and irrigation, and parenteral antibiotics. Superficial infections were treated successfully with wound closure over outflow tubes, and deep infections with inflow-outflow systems. Maintaining the instrumentation in place was possible in most cases. Parenteral antibiotics were maintained for six weeks in every case. PMID:1395319

  3. ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS

    SciTech Connect

    Temmer, M.; Veronig, A. M.

    2009-09-10

    The issue whether Moreton waves are flare-ignited or coronal mass ejection (CME)-driven, or a combination of both, is still a matter of debate. We develop an analytical model describing the evolution of a large-amplitude coronal wave emitted by the expansion of a circular source surface in order to mimic the evolution of a Moreton wave. The model results are confronted with observations of a strong Moreton wave observed in association with the X3.8/3B flare/CME event from 2005 January 17. Using different input parameters for the expansion of the source region, either derived from the real CME observations (assuming that the upward moving CME drives the wave), or synthetically generated scenarios (expanding flare region, lateral expansion of the CME flanks), we calculate the kinematics of the associated Moreton wave signature. Those model input parameters are determined which fit the observed Moreton wave kinematics best. Using the measured kinematics of the upward moving CME as the model input, we are not able to reproduce the observed Moreton wave kinematics. The observations of the Moreton wave can be reproduced only by applying a strong and impulsive acceleration for the source region expansion acting in a piston mechanism scenario. Based on these results we propose that the expansion of the flaring region or the lateral expansion of the CME flanks is more likely the driver of the Moreton wave than the upward moving CME front.

  4. Stellar Archeology : Chemical Compositions and Kinematics

    NASA Astrophysics Data System (ADS)

    Stringer, Bayard; Carney, Bruce

    2011-10-01

    The λ-CDM model of cosmology predicts a hierarchical formation mechanism of galaxies, with smaller units accreting to construct larger ones. The detection of merger events in external galaxies is well known, and the detection and analysis of merger remnants in the Milky Way is a key component in piecing together the history of our home galaxy. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic structure in the Galactic disk, but it is not readily apparent whether this structure is extragalactic or dynamical in origin. The most prominent structures are quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, a subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. A semi-automated, high resolution spectral analysis is applied to 504 F and G dwarf stars, and the results are amenable to Kolmogorov-Smirnov membership hypothesis testing. In all four cases, the kinematic streams have chemistries roughly consistent with the Galactic disk trends, although the statistical analyses suggest some subtle differences.

  5. KINEMATICS OF STELLAR POPULATIONS IN POSTSTARBURST GALAXIES

    SciTech Connect

    Hiner, Kyle D.; Canalizo, Gabriela E-mail: khiner@astro-udec.cl

    2015-01-20

    Poststarburst galaxies host a population of early-type stars (A or F) but simultaneously lack indicators of ongoing star formation such as [O II] emission. Two distinct stellar populations have been identified in these systems: a young poststarburst population superimposed on an older host population. We present a study of nine poststarburst galaxies with the following objectives: (1) to investigate whether and how kinematical differences between the young and old populations of stars can be measured, and (2) to gain insight into the formation mechanism of the young population in these systems. We fit high signal-to-noise spectra with two independent populations in distinct spectral regions: the Balmer region, the Mg IB region, and the Ca triplet when available. We show that the kinematics of the two populations largely track one another if measured in the Balmer region with high signal-to-noise data. Results from examining the Faber-Jackson relation and the fundamental plane indicate that these objects are not kinematically disturbed relative to more evolved spheroids. A case study of the internal kinematics of one object in our sample shows it to be pressure supported and not rotationally dominated. Overall our results are consistent with merger-induced starburst scenarios where the young population is observed during the later stages of the merger.

  6. Kinematics of foldable discrete space cranes

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.

    1985-01-01

    Exact kinematic description of a NASA proposed prototype foldable-deployable discrete space crane are presented. A computer program is developed which maps the geometry of the crane once controlling parameters are specified. The program uses a building block type approach in which it calculates the local coordinates of each repeating cell and then combines them with respect to a global coordinates system.

  7. Constrained tri-sphere kinematic positioning system

    DOEpatents

    Viola, Robert J

    2010-12-14

    A scalable and adaptable, six-degree-of-freedom, kinematic positioning system is described. The system can position objects supported on top of, or suspended from, jacks comprising constrained joints. The system is compatible with extreme low temperature or high vacuum environments. When constant adjustment is not required a removable motor unit is available.

  8. Compton Effect with Non-Relativistic Kinematics

    ERIC Educational Resources Information Center

    Shivalingaswamy, T.; Kagali, B. A.

    2011-01-01

    In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…

  9. Action Experience Changes Attention to Kinematic Cues

    PubMed Central

    Filippi, Courtney A.; Woodward, Amanda L.

    2016-01-01

    The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-months-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation) about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue) or did not match the orientation of the rod (incongruent cue). To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first) × 2 (congruent kinematic cue vs. incongruent kinematic cue) between-subjects design. We show that 13-months-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics. PMID:26913012

  10. Kinematic comparisons of 1996 Olympic baseball pitchers.

    PubMed

    Escamilla, R F; Fleisig, G S; Zheng, N; Barrentine, S W; Andrews, J R

    2001-09-01

    The aim of this study was to compare and evaluate the kinematics of baseball pitchers who participated in the 1996 XXVI Centennial Olympic Games. Two synchronized video cameras operating at 120 Hz were used to video 48 pitchers from Australia, Japan, the Netherlands, Cuba, Italy, Korea, Nicaragua and the USA. All pitchers were analysed while throwing the fastball pitch. Twenty-one kinematic parameters were measured at lead foot contact, during the arm cocking and arm acceleration phases, and at the instant of ball release. These parameters included stride length, foot angle and foot placement; shoulder abduction, shoulder horizontal adduction and shoulder external rotation; knee and elbow flexion; upper torso, shoulder internal rotation and elbow extension angular velocities; forward and lateral trunk tilt; and ball speed. A one-way analysis of variance (P < 0.01) was used to assess kinematic differences. Shoulder horizontal adduction and shoulder external rotation at lead foot contact and ball speed at the instant of ball release were significantly different among countries. The greater shoulder horizontal abduction observed in Cuban pitchers at lead foot contact is thought to be an important factor in the generation of force throughout the arm cocking and arm acceleration phases, and may in part explain why Cuban pitchers generated the greatest ball release speed. We conclude that pitching kinematics are similar among baseball pitchers from different countries.

  11. Kinematic Measurements from YouTube Videos

    ERIC Educational Resources Information Center

    Ruiz, Michael J.

    2009-01-01

    Video analysis of motion has been in use now for some time. However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers.…

  12. Kinematics of luminous blue compact galaxies

    NASA Astrophysics Data System (ADS)

    Östlin, Göran; Amram, Philippe; Boulesteix, Jaques; Bergvall, Nils; Masegosa, Josefa; Márquez, Isabel

    We present results from a Fabry-Perot study of the Hα velocity fields and morphologies of a sample of luminous blue compact galaxies. We estimate masses from photometry and kinematics and show that many of these BCGs are not rotationally supported. Mergers or strong interactions appear to be the triggering mechanism of the extreme starbursts seen in these galaxies.

  13. Detailed stellar and gaseous kinematics of M31

    NASA Astrophysics Data System (ADS)

    Opitsch, Michael; Fabricius, Maximilian; Saglia, Roberto; Bender, Ralf; Williams, Michael

    2015-02-01

    We have collected optical integral field spectroscopic data for M31 with the spectrograph VIRUS-W that result in kinematic maps of unprecedented detail. These reveal the presence of two kinematically distinct gas components.

  14. Camera-Only Kinematics for Small Lunar Rovers

    NASA Astrophysics Data System (ADS)

    Fang, E.; Suresh, S.; Whittaker, W.

    2016-11-01

    Knowledge of the kinematic state of rovers is critical. Existing methods add sensors and wiring to moving parts, which can fail and adds mass and volume. This research presents a method to optically determine kinematic state using a single camera.

  15. Spinal cord compression due to ethmoid adenocarcinoma.

    PubMed

    Johns, D R; Sweriduk, S T

    1987-10-15

    Adenocarcinoma of the ethmoid sinus is a rare tumor which has been epidemiologically linked to woodworking in the furniture industry. It has a low propensity to metastasize and has not been previously reported to cause spinal cord compression. A symptomatic epidural spinal cord compression was confirmed on magnetic resonance imaging (MRI) scan in a former furniture worker with widely disseminated metastases. The clinical features of ethmoid sinus adenocarcinoma and neoplastic spinal cord compression, and the comparative value of MRI scanning in the neuroradiologic diagnosis of spinal cord compression are reviewed.

  16. The Maiden Voyage of a Kinematics Robot

    NASA Astrophysics Data System (ADS)

    Greenwolfe, Matthew L.

    2015-04-01

    In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

  17. Kinematic Downsizing at z ∼ 2

    NASA Astrophysics Data System (ADS)

    Simons, Raymond C.; Kassin, Susan A.; Trump, Jonathan R.; Weiner, Benjamin J.; Heckman, Timothy M.; Barro, Guillermo; Koo, David C.; Guo, Yicheng; Pacifici, Camilla; Koekemoer, Anton; Stephens, Andrew W.

    2016-10-01

    We present results from a survey of the internal kinematics of 49 star-forming galaxies at z∼ 2 in the CANDELS fields with the Keck/MOSFIRE spectrograph, Survey in the near-Infrared of Galaxies with Multiple position Angles (SIGMA). Kinematics (rotation velocity V rot and gas velocity dispersion {σ }g) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z∼ 2, massive star-forming galaxies ({log} {M}* /{M}ȯ ≳ 10.2) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully–Fisher relation. These massive galaxies have values of {V}{rot}/{σ }g that are factors of 2–5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low-mass galaxies ({log} {M}* /{M}ȯ ≲ 10.2) at this epoch are still in the early stages of disk assembly: their kinematics are often dominated by gas velocity dispersion and they fall from the Tully–Fisher relation to significantly low values of V rot. This “kinematic downsizing” implies that the process(es) responsible for disrupting disks at z∼ 2 have a stronger effect and/or are more active in low-mass systems. In conclusion, we find that the period of rapid stellar mass growth at z∼ 2 is coincident with the nascent assembly of low-mass disks and the assembly and settling of high-mass disks.

  18. Kinematic Optimization in Birds, Bats and Ornithopters

    NASA Astrophysics Data System (ADS)

    Reichert, Todd

    Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

  19. Three-dimensional kinematics of hummingbird flight.

    PubMed

    Tobalske, Bret W; Warrick, Douglas R; Clark, Christopher J; Powers, Donald R; Hedrick, Tyson L; Hyder, Gabriel A; Biewener, Andrew A

    2007-07-01

    Hummingbirds are specialized for hovering flight, and substantial research has explored this behavior. Forward flight is also important to hummingbirds, but the manner in which they perform forward flight is not well documented. Previous research suggests that hummingbirds increase flight velocity by simultaneously tilting their body angle and stroke-plane angle of the wings, without varying wingbeat frequency and upstroke: downstroke span ratio. We hypothesized that other wing kinematics besides stroke-plane angle would vary in hummingbirds. To test this, we used synchronized high-speed (500 Hz) video cameras and measured the three-dimensional wing and body kinematics of rufous hummingbirds (Selasphorus rufus, 3 g, N=5) as they flew at velocities of 0-12 m s(-1) in a wind tunnel. Consistent with earlier research, the angles of the body and the stroke plane changed with velocity, and the effect of velocity on wingbeat frequency was not significant. However, hummingbirds significantly altered other wing kinematics including chord angle, angle of attack, anatomical stroke-plane angle relative to their body, percent of wingbeat in downstroke, wingbeat amplitude, angular velocity of the wing, wingspan at mid-downstroke, and span ratio of the wingtips and wrists. This variation in bird-centered kinematics led to significant effects of flight velocity on the angle of attack of the wing and the area and angles of the global stroke planes during downstroke and upstroke. We provide new evidence that the paths of the wingtips and wrists change gradually but consistently with velocity, as in other bird species that possess pointed wings. Although hummingbirds flex their wings slightly at the wrist during upstroke, their average wingtip-span ratio of 93% revealed that they have kinematically ;rigid' wings compared with other avian species.

  20. Absolute magnitudes and kinematics of barium stars.

    NASA Astrophysics Data System (ADS)

    Gomez, A. E.; Luri, X.; Grenier, S.; Prevot, L.; Mennessier, M. O.; Figueras, F.; Torra, J.

    1997-03-01

    The absolute magnitude of barium stars has been obtained from kinematical data using a new algorithm based on the maximum-likelihood principle. The method allows to separate a sample into groups characterized by different mean absolute magnitudes, kinematics and z-scale heights. It also takes into account, simultaneously, the censorship in the sample and the errors on the observables. The method has been applied to a sample of 318 barium stars. Four groups have been detected. Three of them show a kinematical behaviour corresponding to disk population stars. The fourth group contains stars with halo kinematics. The luminosities of the disk population groups spread a large range. The intrinsically brightest one (M_v_=-1.5mag, σ_M_=0.5mag) seems to be an inhomogeneous group containing barium binaries as well as AGB single stars. The most numerous group (about 150 stars) has a mean absolute magnitude corresponding to stars in the red giant branch (M_v_=0.9mag, σ_M_=0.8mag). The third group contains barium dwarfs, the obtained mean absolute magnitude is characteristic of stars on the main sequence or on the subgiant branch (M_v_=3.3mag, σ_M_=0.5mag). The obtained mean luminosities as well as the kinematical results are compatible with an evolutionary link between barium dwarfs and classical barium giants. The highly luminous group is not linked with these last two groups. More high-resolution spectroscopic data will be necessary in order to better discriminate between barium and non-barium stars.

  1. Learning Kinematics with a V-Scope: A Case Study.

    ERIC Educational Resources Information Center

    Trumper, Ricardo

    1997-01-01

    Studies the effect of V-Scope activities on the performance of 11th-grade students in analyzing kinematics graphs. Students were challenged to construct different kinds of graphs using their own movements as well as the motion of a dynamics cart. Results indicate that the V-Scope kinematics laboratory activities can promote kinematics concepts and…

  2. Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations

    ERIC Educational Resources Information Center

    Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto

    2011-01-01

    The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm's length. Kinematic variables (hand peak…

  3. Spinal motion and intradiscal pressure measurements before and after lumbar spine instrumentation with titanium or PEEK rods.

    PubMed

    Abode-Iyamah, Kingsley; Kim, Sam Byeong; Grosland, Nicole; Kumar, Rajinder; Belirgen, Muhittin; Lim, Tae Hong; Torner, James; Hitchon, Patrick W

    2014-04-01

    Spinal instrumentation and fusion have been incriminated as contributing to adjacent segment degeneration (ASD). It has been suggested that ASD results from increased range of motion and intradiscal pressure (IDP) adjacent to instrumentation. Posterior dynamic stabilization with polyetheretherketone (PEEK) rods has been proposed as potentially advantageous compared to rigid instrumentation with titanium (Ti) rods in reducing the incidence of ASD. We evaluated segmental motions in the cadaveric spine instrumented with PEEK or Ti rods from L3 to S1, as well as the adjacent segment motions and IDP at L1-2 and L2-3. Human cadaveric spines were potted at T12-L1 and S1-2. Spinal instrumentation from L3-S1 was accomplished using pedicle screws with either PEEK or Ti rods. Specimens were subjected to displacement controlled testing: 15° flexion, 15° extension, 10° lateral bending, and 5° right axial rotation using the MTS machine (MTS, Minneapolis, MN, USA). Intradiscal pressure was measured by placing pressure transducers into the intervertebral disc at L1-2 and L2-3. Spinal motion of L2 relative to L3, and L3 relative to S1 was tracked using a three dimensional motion analysis system. Instrumentation with PEEK and Ti rods was associated with a decrease in L3-S1 motion compared to the intact state that was significant in flexion (p=0.002), and extension (p=0.0075). Instrumentation with PEEK and Ti rods was associated with an increase in IDP at L1-2 that was significant in flexion (p=0.0028). Instrumentation with either PEEK or Ti rods resulted in decreased motion at the instrumented levels while increasing IDP at the adjacent level.

  4. Are there a guidelines for implantable spinal cord stimulator therapy in patients using chronic anticoagulation therapy? - A review of decision-making in the high-risk patient

    PubMed Central

    Ghaly, Ramsis F.; Lissounov, Alexei; Candido, Kenneth D.; Knezevic, Nebojsa Nick

    2016-01-01

    Background: Spinal cord stimulators (SCSs) are gaining increasing indications and utility in an expanding variety of clinical conditions. Complications and initial expenses have historically prevented the early use of SCS therapy despite ongoing efforts to educate and promote its utilization. At present, there exists no literature evidence of SCS implantation in a chronically anticoagulated patient, and neuromodulation manufacturers are conspicuously silent in providing warnings or recommendations in the face of anticoagulant use chronically. It would appear as through these issues demand scrutiny and industry as well as neuromodulation society advocacy and support in terms of the provision of coherent guidelines on how to proceed. Case Description: A 79-year-old male returned to the neurosurgical clinic with persistent low back pain and leg heaviness due to adjacent level degenerative spondylosis and severe thoracic spinal stenosis. The patient had a notable history of multiple comorbidities along with atrial fibrillation requiring chronic anticoagulation. On initial presentation, he was educated with three choice of conservative medical therapy, intrathecal drug delivery system implantation, or additional lumbar decompression laminectomy with instrumented fusion of T10-L3 and a palliative surgical lead SCS implantation. Description: A 79-year-old male returned to the neurosurgical clinic with persistent low back pain and leg heaviness due to adjacent level degenerative spondylosis and severe thoracic spinal stenosis. The patient had a notable history of multiple comorbidities along with atrial fibrillation requiring chronic anticoagulation. On initial presentation, he was educated with three choice of conservative medical therapy, intrathecal drug delivery system implantation, or additional lumbar decompression laminectomy with instrumented fusion of T10-L3 and a palliative surgical lead SCS implantation. Conclusion: Our literature search did not reveal any

  5. Fetal segmental spinal dysgenesis and unusual segmental agenesis of the anterior spinal artery.

    PubMed

    Valdez Quintana, Melissa; Michaud, Jean; El-Chaar, Darine; El Demellawy, Dina; Nikkel, Sarah M; Miller, Elka

    2016-08-01

    Segmental spinal dysgenesis (SSD) is a rare congenital spinal abnormality characterized by segmental dysgenesis or agenesis of the thoracolumbar or lumbar spine, congenital kyphosis, and abnormal configuration of the underlying spinal cord. A unique feature of SSD is that the vertebrae are present above and below the defect, and there is often a lower cord segment in the caudal spinal canal. We report a fetal MRI case of SSD with postmortem and neuropathological correlations. Our report confirms already published findings including the presence of a neurenteric cyst but is the first to document anterior spinal artery segmental agenesis in SSD. PMID:26969176

  6. Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation

    PubMed Central

    2012-01-01

    Background The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). Methods In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. Results Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Conclusions Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small

  7. Spinal deformity after multilevel osteoplastic laminotomy

    PubMed Central

    Juergen, Krauss; Gloger, Harald; Soerensen, Nils; Wild, Alexander

    2007-01-01

    Multilevel laminectomy in children has a significant rate of postoperative spinal deformity. To decrease the incidence of this complication, the use of osteoplastic laminotomy is advocated to minimise the risk of spinal deformity by preserving the normal architecture of the spine. In this retrospective study, a 10-year series of a paediatric population undergoing multilevel osteoplastic laminotomy is reviewed to determine the incidence, especially in contrast to laminectomies, and to identify factors that affect the occurrence of spinal column deformity. Seventy patients (mean age 4.2 years) underwent multilevel osteoplastic laminotomy for congenital anomalies or removal of spinal tumours. All patients had a clinical and radiographic examination preoperatively, 12 months postoperatively and at follow-up. Mean follow-up was 5.3 years (range 3–12.6 years). Nineteen patients (27%) had a new or progressive spinal deformity. There was an increased incidence in patients who had surgery for spinal tumours (P < 0.05), surgery of the cervical spine (P < 0.01), and who had more than five levels of the spine included (P < 0.05). A review of the literature on children with multilevel laminectomy (n = 330), the incidence of spinal deformity found a significantly higher (46%) compared to our study group. This study demonstrates that osteoplastic laminotomy was found to be very effective in decreasing the incidence of spinal deformities after spinal-canal surgery for spinal-cord tumours or congenital anomalies in children and adolescents. The choice of an anatomical reconstructive surgical technique such as osteoplastic laminotomy seems to be essential to minimise secondary problems due to the surgical technique itself. Nevertheless, growing patients should be followed up for several years after the initial operation for early detection and consequent management of any possible deformity of the spinal column. PMID:17323095

  8. Spinal circuits can accommodate interaction torques during multijoint limb movements

    PubMed Central

    Buhrmann, Thomas; Di Paolo, Ezequiel A.

    2014-01-01

    The dynamic interaction of limb segments during movements that involve multiple joints creates torques in one joint due to motion about another. Evidence shows that such interaction torques are taken into account during the planning or control of movement in humans. Two alternative hypotheses could explain the compensation of these dynamic torques. One involves the use of internal models to centrally compute predicted interaction torques and their explicit compensation through anticipatory adjustment of descending motor commands. The alternative, based on the equilibrium-point hypothesis, claims that descending signals can be simple and related to the desired movement kinematics only, while spinal feedback mechanisms are responsible for the appropriate creation and coordination of dynamic muscle forces. Partial supporting evidence exists in each case. However, until now no model has explicitly shown, in the case of the second hypothesis, whether peripheral feedback is really sufficient on its own for coordinating the motion of several joints while at the same time accommodating intersegmental interaction torques. Here we propose a minimal computational model to examine this question. Using a biomechanics simulation of a two-joint arm controlled by spinal neural circuitry, we show for the first time that it is indeed possible for the neuromusculoskeletal system to transform simple descending control signals into muscle activation patterns that accommodate interaction forces depending on their direction and magnitude. This is achieved without the aid of any central predictive signal. Even though the model makes various simplifications and abstractions compared to the complexities involved in the control of human arm movements, the finding lends plausibility to the hypothesis that some multijoint movements can in principle be controlled even in the absence of internal models of intersegmental dynamics or learned compensatory motor signals. PMID:25426061

  9. Acute effects of Dry Immersion on kinematic characteristics of postural corrective responses

    NASA Astrophysics Data System (ADS)

    Sayenko, D. G.; Miller, T. F.; Melnik, K. A.; Netreba, A. I.; Khusnutdinova, D. R.; Kitov, V. V.; Tomilovskaya, E. S.; Reschke, M. F.; Gerasimenko, Y. P.; Kozlovskaya, I. B.

    2016-04-01

    Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

  10. Nutrition of People with Spinal Cord Injuries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This conference proceeding summarizes current knowledge about the nutritional status and needs of the spinal cord injured patient. Topics covered include the aspects of spinal cord injury that influence nutrient intakes and status, and the nutrients most likely to be problematic in this diverse gro...

  11. Intraoperative neurophysiological monitoring in spinal surgery

    PubMed Central

    Park, Jong-Hwa; Hyun, Seung-Jae

    2015-01-01

    Recently, many surgeons have been using intraoperative neurophysiological monitoring (IOM) in spinal surgery to reduce the incidence of postoperative neurological complications, including level of the spinal cord, cauda equina and nerve root. Several established technologies are available and combined motor and somatosensory evoked potentials are considered mandatory for practical and successful IOM. Spinal cord evoked potentials are elicited compound potentials recorded over the spinal cord. Electrical stimulation is provoked on the dorsal spinal cord from an epidural electrode. Somatosensory evoked potentials assess the functional integrity of sensory pathways from the peripheral nerve through the dorsal column and to the sensory cortex. For identification of the physiological midline, the dorsal column mapping technique can be used. It is helpful for reducing the postoperative morbidity associated with dorsal column dysfunction when distortion of the normal spinal cord anatomy caused by an intramedullary cord lesion results in confusion in localizing the midline for the myelotomy. Motor evoked potentials (MEPs) consist of spinal, neurogenic and muscle MEPs. MEPs allow selective and specific assessment of the functional integrity of descending motor pathways, from the motor cortex to peripheral muscles. Spinal surgeons should understand the concept of the monitoring techniques and interpret monitoring records adequately to use IOM for the decision making during the surgery for safe surgery and a favorable surgical outcome. PMID:26380823

  12. Therapeutic approaches for spinal cord injury.

    PubMed

    Cristante, Alexandre Fogaça; Barros Filho, Tarcísio Eloy Pessoa de; Marcon, Raphael Martus; Letaif, Olavo Biraghi; Rocha, Ivan Dias da

    2012-10-01

    This study reviews the literature concerning possible therapeutic approaches for spinal cord injury. Spinal cord injury is a disabling and irreversible condition that has high economic and social costs. There are both primary and secondary mechanisms of damage to the spinal cord. The primary lesion is the mechanical injury itself. The secondary lesion results from one or more biochemical and cellular processes that are triggered by the primary lesion. The frustration of health professionals in treating a severe spinal cord injury was described in 1700 BC in an Egyptian surgical papyrus that was translated by Edwin Smith; the papyrus reported spinal fractures as a "disease that should not be treated." Over the last biological or pharmacological treatment method. Science is unraveling the mechanisms of cell protection and neuroregeneration, but clinically, we only provide supportive care for patients with spinal cord injuries. By combining these treatments, researchers attempt to enhance the functional recovery of patients with spinal cord injuries. Advances in the last decade have allowed us to encourage the development of experimental studies in the field of spinal cord regeneration. The combination of several therapeutic strategies should, at minimum, allow for partial functional recoveries for these patients, which could improve their quality of life. PMID:23070351

  13. Psychological Aspects of Spinal Cord Injury

    ERIC Educational Resources Information Center

    Cook, Daniel W.

    1976-01-01

    Reviewing literature on the psychological impact of spinal cord injury suggests: (a) depression may not be a precondition for injury adjustment; (b) many persons sustaining cord injury may have experienced psychological disruption prior to injury; and (c) indexes of rehabilitation success need to be developed for the spinal cord injured. (Author)

  14. Epidemiology of spinal cord injury.

    PubMed

    Kurtzke, J F

    1977-01-01

    Accidents are the cause of some 50 deaths per 100 000 population each year in the US; some 3% of these are from traumatic spinal cord injury alone. Traumatic spinal cord injury in socioeconomically advanced countries, has a probably annual incidence rate of 3 per 100 000 population. Males are affected five times as often as females, and in the US, Negroes have twice the rates of whites. Half the cases are due to motor vehicle accidents, 1/4 to falls, and 1/10 to sports injuries. Maximal ages at risk are 15 to 34; only for cord damage due to falls do this risk differ, and here elderly are the more prone. Associated injuries are common in traumatic cord injury, and head injury and pulmonary dysfunction are frequent causes of the acute deaths in traumatic SCI which is why complete quadriplegia has a high early case-fatality ratio. Late deaths in SCI are principally the direct or indirect result of the neurogenic bladder. With treatment in comprehensive spinal cord injury centers, more than 4 of 5 traumatic SCI patients will survive ten years with an average of almost 18 years. Median survival may be almost 14 years for complete quadriplegia, 17 for complete paraplegia, 19 for incomplete quadriplegia, 20 for incomplete paraplegia and 28 for cauda equina lesions. Prevalence is likely to be some 50 per 100 000 population with about 20 per 100 000 completely paralyzed (3 quadriplegic and 19 paraplegic). Some 4 out of 5 survivors of traumatic SCI should be able to live at home and perform gainful work after such treatment. PMID:616527

  15. Fictive motor patterns in chronic spinal cats.

    PubMed

    Pearson, K G; Rossignol, S

    1991-12-01

    1. Fictive motor patterns were recorded in hind leg nerves of 10 adult chronic spinal cats (spinalized at T13). Four of these animals had been trained to step with their hind legs on a treadmill (late-spinal animals), whereas the remainder received no training and were examined a short time after spinalization (early-spinal animals). 2. A fictive pattern resembling the locomotor pattern for stepping was evoked in all animals in response to stimulation of the skin of the perineal region. (2-[2,6-Dichloroaniline]-2-imidazoline) hydrochloride (Clonidine) at doses ranging from 100 to 500 micrograms/kg iv facilitated the production of this pattern, particularly in early-spinal animals. 3. The fictive locomotor pattern in late-spinal animals was more complex than that occurring in early-spinal animals. In the latter the pattern consisted of an alternation of activity in flexor and extensor nerves, and changing leg position did not qualitatively alter the pattern, whereas in late-spinal animals the relative durations of the bursts in different flexors were usually not the same, and the pattern of flexor activity was dependent on leg position. 4. Moving the legs from extension to flexion progressively decreased the duration of flexor bursts, increased the cycle period, and decreased the ease with which the pattern could be evoked in both early- and late-spinal animals. 5. 1-beta-3,4-Dihydroxyphenylalanine (DOPA)/Isonocotinic acid 2-[(2-benzylcarbamoyl)ethyl]hydrazide (Nialamide) treatment following Clonidine in early-spinal animals increased the complexity of flexor burst activity. This, and other observations, indicates that DOPA and Clonidine do not have strictly identical actions on the locomotor pattern generator. 6. Stimulation of the paws in late-spinal animals produced two patterns of activity distinctly different from the locomotor pattern. of activity distinctly different from the locomotor pattern. One was a short sequence of high-frequency rhythmic activity (at

  16. Kinematics of Earth Impacting Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Colaninno, R. C.; Vourlidas, A.

    2012-12-01

    With the data from the STEREO mission, we are able to continuously monitor Coronal Mass Ejections (CMEs) as they progress from the Sun to Earth. However, even with continuous monitoring with remote sensing observations, we are still unable to accurately predict the arrival or terrestrial impact of a CME. In this study, we analyze nine CMEs from the Sun to Earth as observed in both the remote sensing and in situ data sets. In this study, we track nine CMEs from the Sun to 70% - 98% of the distance to Earth with the remote sensing data. We use the Graduate Cyclical Shell (GCS) model to estimate the position of each CME as it is observed in the inner heliosphere. From the derived kinematics, we compare the predicted arrival times and impact velocities with the in situ data. We consider different method for fitting the kinematics and the modeled geometry of the CME to improve the predicted arrival time.

  17. The kinematic advantage of electric cars

    NASA Astrophysics Data System (ADS)

    Meyn, Jan-Peter

    2015-11-01

    Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

  18. On the kinematic age of RZ Psc

    NASA Astrophysics Data System (ADS)

    Potravnov, I. S.; Grinin, V. P.

    2013-11-01

    RZ Psc belongs to the family of young UX Ori stars whose photometric activity is due to strong extinction variations in the circumstellar disks surrounding them. However, in contrast to all the remaining stars of this type, no evidence of youth has been detected for RZ Psc until recently. A rough estimate of the star's kinematic age was made for the first time in our previous paper (Grinin et al. 2010). It shows that RZ Psc is intermediate in its evolutionary status between young stars in Orion and stars with debris disks. In this paper, we provide a refined estimate of the kinematic age for the star confirming this conclusion. According to this estimate, the age of RZ Psc is approximately 25 ± 5 Myr at M * = 1 M ⊙.

  19. Kinematic measurements using an infrared sensor

    NASA Astrophysics Data System (ADS)

    Marinho, F.; Paulucci, L.

    2016-03-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4-30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems.

  20. Plasma electron hole kinematics. I. Momentum conservation

    NASA Astrophysics Data System (ADS)

    Hutchinson, I. H.; Zhou, C.

    2016-08-01

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  1. Kinematics of the symbiotic system R Aqr

    NASA Astrophysics Data System (ADS)

    Navarro, S.; Corral, L. J.; Steffen, W.

    2014-04-01

    We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.

  2. The kinematic origin of the cosmological redshift

    NASA Astrophysics Data System (ADS)

    Bunn, Emory F.; Hogg, David W.

    2009-08-01

    A common belief about big-bang cosmology is that the cosmological redshift cannot be properly viewed as a Doppler shift (that is, as evidence for a recession velocity) but must be viewed in terms of the stretching of space. We argue that, contrary to this view, the most natural interpretation of the redshift is as a Doppler shift, or rather as the accumulation of many infinitesimal Doppler shifts. The stretching-of-space interpretation obscures a central idea of relativity, namely that it is always valid to choose a coordinate system that is locally Minkowskian. We show that an observed frequency shift in any spacetime can be interpreted either as a kinematic (Doppler) shift or a gravitational shift by imagining a suitable family of observers along the photon's path. In the context of the expanding universe, the kinematic interpretation corresponds to a family of comoving observers and hence is more natural.

  3. Sphingolipids in spinal cord injury

    PubMed Central

    Jones, Zachary B; Ren, Yi

    2016-01-01

    Spinal cord injury (SCI) is a debilitating condition that affects millions of individuals worldwide. Despite progress over the last few decades, the molecular mechanisms of secondary SCI that continue to occur days and weeks after the original trauma remain poorly understood. As a result, current therapies for SCI are only marginally effective. Sphingolipids, a diverse class of bioactive lipids, have been shown to regulate SCI repair and key secondary injury processes such as apoptosis, ischemia and inflammation. This review will discuss the numerous roles of sphingolipids and highlight the potential of sphingolipid-targeted therapies for SCI. PMID:27570580

  4. Parasitic and rare spinal infections.

    PubMed

    do Amaral, Lázaro Luís Faria; Nunes, Renato Hoffmann; da Rocha, Antonio Jose

    2015-05-01

    The imaging features of spinal parasitic diseases and other rare infections are herein discussed. These diseases are distributed worldwide, with increased prevalence in areas with poor sanitary conditions and in developing countries. In nonendemic areas, sporadic cases may occur, consequent to increased international travel and immunocompromising conditions. Infectious diseases are usually treatable, and early detection is often crucial. A thorough comprehension of the imaging patterns associated with the clinical features, epidemiology, and laboratory results allows the radiologist to narrow down the options for differential diagnosis and facilitates the timely implementation of appropriate therapies. PMID:25952177

  5. Ambulation and spinal cord injury.

    PubMed

    Hardin, Elizabeth C; Kobetic, Rudi; Triolo, Ronald J

    2013-05-01

    Walking is possible for many patients with a spinal cord injury. Avenues enabling walking include braces, robotics and FES. Among the benefits are improved musculoskeletal and mental health, however unrealistic expectations may lead to negative changes in quality of life. Use rigorous assessment standards to gauge the improvement of walking during the rehabilitation process, but also yearly. Continued walking after discharge may be limited by challenges, such as lack of accessibility in and outside the home, and complications, such as shoulder pain or injuries from falls. It is critical to determine the risks and benefits of walking for each patient.

  6. Sphingolipids in spinal cord injury.

    PubMed

    Jones, Zachary B; Ren, Yi

    2016-01-01

    Spinal cord injury (SCI) is a debilitating condition that affects millions of individuals worldwide. Despite progress over the last few decades, the molecular mechanisms of secondary SCI that continue to occur days and weeks after the original trauma remain poorly understood. As a result, current therapies for SCI are only marginally effective. Sphingolipids, a diverse class of bioactive lipids, have been shown to regulate SCI repair and key secondary injury processes such as apoptosis, ischemia and inflammation. This review will discuss the numerous roles of sphingolipids and highlight the potential of sphingolipid-targeted therapies for SCI. PMID:27570580

  7. Neuroimaging of Spinal Canal Stenosis.

    PubMed

    Cowley, Peter

    2016-08-01

    Spinal stenosis is common and presents in a variety of forms. Symptomatic lumbar stenosis occurs in approximately 10% of the population and cervical stenosis in 9% over age 70. Imaging is central to the management decision process and first-choice MR imaging may be substituted with CT and CT myelography. A review of the literature is presented with particular emphasis on the clinical-radiologic correlation in both neurogenic intermittent claudication and cervical spondylotic myelopathy. Advanced techniques promise improvements, particularly with radicular compressive lesions, but remain underutilized in routine clinical practice.

  8. Spinal morphine anesthesia and urinary retention.

    PubMed

    Mahan, K T; Wang, J

    1993-11-01

    Spinal anesthetic is a common form of surgical anesthetic used in foot and ankle surgery. Spinal morphine anesthetic is less common, but has the advantage of providing postoperative analgesia for 12 to 24 hr. A number of complications can occur with spinal anesthesia, including urinary retention that may be a source of severe and often prolonged discomfort and pain for the patient. Management of this problem may require repeated bladder catheterization, which may lead to urinary tract infections or impairment of urethrovesicular function. This study reviews the incidence of urinary retention in 80 patients (40 after general anesthesia and 40 after spinal anesthesia) who underwent foot and ankle surgery at Saint Joseph's Hospital, Philadelphia, PA. Twenty-five percent of the patients who had spinal anesthesia experienced urinary retention, while only 7 1/2% of the group who had general anesthesia had this complication. Predisposing factors, treatment regimen, and recommendations for the prevention and management of urinary retention are presented.

  9. The human spinal cord interprets velocity-dependent afferent input during stepping.

    PubMed

    Beres-Jones, Janell A; Harkema, Susan J

    2004-10-01

    We studied the motor response to modifying the rate of application of sensory input to the human spinal cord during stepping. We measured the electromyographic (EMG), kinematic and kinetic patterns of the legs during manually assisted or unassisted stepping using body weight support on a treadmill (BWST) in eight individuals with spinal cord injury (SCI). At various treadmill speeds (0.27-1.52 m/s), we measured the EMG activity of the soleus (SOL), medial gastrocnemius (MG), tibialis anterior (TA), medial hamstrings (MH), vastus lateralis (VL), rectus femoris (RF) and iliopsoas (ILIO); the hip, knee and ankle joint angles; the amount of body weight support (BWS); and lower limb loading. The EMG amplitude and burst duration of the SOL, MG, TA, MH, VL, RF and ILIO were related to the step cycle duration during stepping using BWST. EMG mean amplitudes increased at faster treadmill speeds, and EMG burst durations shortened with decreased step cycle durations. Muscle stretch of an individual muscle could not account for the EMG amplitude modulation in response to stepping speed. The effects on the EMG amplitude and burst duration were similar in subjects with partial and no detectable supraspinal input. We propose that the human spinal cord can interpret complex step-related, velocity-dependent afferent information to contribute to the neural control of stepping.

  10. Kinematics of Hooke universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Mckinney, William S., Jr.

    1988-01-01

    The singularity problem associated with wrist mechanisms commonly found on industrial manipulators can be alleviated by redesigning the wrist so that it functions as a three-axis gimbal system. This paper discussess the kinematics of gimbal robot wrists made of one and two Hooke universal joints. Derivations of the resolved rate motion control equations for the single and double Hooke universal joint wrists are presented using the three-axis gimbal system as a theoretical wrist model.

  11. Kinematics and dynamics of sphenisciform wings

    NASA Astrophysics Data System (ADS)

    Noca, Flavio; Crisinel, Fabien; Munier, Pierre

    2011-11-01

    Three-dimensional scans of three different species of taxidermied penguins (Aptenodytes patagonicus, Pygoscelis papua, and Spheniscus magellanicus) have been performed. A three-dimensional reproduction of an African penguin (Sphenicus demersus) wing was manufactured and tested in a hydrodynamic channel. A six-degree-of-freedom robot was programmed to perform the three dimensional kinematics, obtained from actual footage. A six-component force balance was used to retrieve the dynamics of the wing motion. Results will be presented and discussed.

  12. Lower extremity kinematics of athletics curve sprinting.

    PubMed

    Alt, Tobias; Heinrich, Kai; Funken, Johannes; Potthast, Wolfgang

    2015-01-01

    Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion-adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention. PMID:25495196

  13. Ergonomics and biology of spinal rotation.

    PubMed

    Kumar, Shrawan

    2004-03-15

    Spinal rotation, though being a very common motion of the body, is poorly understood. Furthermore, this motion and the extent of its development is unique to the human. Beyond the extent of its need in common activities, spinal rotation is a destabilizating motion for an inherently unstable structure. Spinal rotation has been argued to be an essential feature for an efficient bipedal gait. Also, it provides leverage to the upper extremities in delivering a forceful impact. An artificial restriction/elimination of spinal rotation resulted in significantly shorter stride length, slower walking velocity, and higher energy consumption in walking (p < 0.05). Spinal rotation also decreases the amount of force the spinal muscles can generate (to 25% of spinal extension). However, its extensive employment in industrial activities has been associated with 60.4% of back injuries. It is further stated that the amount of scientific information currently available is inadequate to biomechanically model the spinal response in a working environment. For example, when the spine is pre-rotated, a further rotation in the direction of pre-rotation decreases the force production significantly (p < 0.01) and increases the EMG activity significantly (p < 0.01) but the pattern changes with effort in the opposite direction. This and other properties (described in the paper) render biomechanical models inadequate. Muscle activation pattern and neuromotor behaviour of spinal muscles in flexion/extension and rotation of the spine are significantly different from each other (p < 0.01). The localized fatigue in different spinal muscles in the same contraction is significantly different and has been called differential fatigue. Finally, the trunk rotation, being pivotal for bipedal locomotion has brought many back problems to the human race.

  14. Degenerative spinal disease in large felids.

    PubMed

    Kolmstetter, C; Munson, L; Ramsay, E C

    2000-03-01

    Degenerative spinal disorders, including intervertebral disc disease and spondylosis, seldom occur in domestic cats. In contrast, a retrospective study of 13 lions (Panthera leo), 16 tigers (Panthera tigris), 4 leopards (Panthera pardis), 1 snow leopard (Panthera uncia), and 3 jaguars (Panthera onca) from the Knoxville Zoo that died or were euthanatized from 1976 to 1996 indicated that degenerative spinal disease is an important problem in large nondomestic felids. The medical record, radiographic data, and the necropsy report of each animal were examined for evidence of intervertebral disc disease or spondylosis. Eight (three lions, four tigers, and one leopard) animals were diagnosed with degenerative spinal disease. Clinical signs included progressively decreased activity, moderate to severe rear limb muscle atrophy, chronic intermittent rear limb paresis, and ataxia. The age at onset of clinical signs was 10-19 yr (median = 18 yr). Radiographic evaluation of the spinal column was useful in assessing the severity of spinal lesions, and results were correlated with necropsy findings. Lesions were frequently multifocal, included intervertebral disc mineralization or herniation with collapsed intervertebral disc spaces, and were most common in the lumbar area but also involved cervical and thoracic vertebrae. Marked spondylosis was present in the cats with intervertebral disc disease, presumably subsequent to vertebral instability. Six of the animals' spinal cords were examined histologically, and five had acute or chronic damage to the spinal cord secondary to disc protrusion. Spinal disease should be suspected in geriatric large felids with decreased appetite or activity. Radiographic evaluation of the spinal column is the most useful method to assess the type and severity of spinal lesions.

  15. Degenerative spinal disease in large felids.

    PubMed

    Kolmstetter, C; Munson, L; Ramsay, E C

    2000-03-01

    Degenerative spinal disorders, including intervertebral disc disease and spondylosis, seldom occur in domestic cats. In contrast, a retrospective study of 13 lions (Panthera leo), 16 tigers (Panthera tigris), 4 leopards (Panthera pardis), 1 snow leopard (Panthera uncia), and 3 jaguars (Panthera onca) from the Knoxville Zoo that died or were euthanatized from 1976 to 1996 indicated that degenerative spinal disease is an important problem in large nondomestic felids. The medical record, radiographic data, and the necropsy report of each animal were examined for evidence of intervertebral disc disease or spondylosis. Eight (three lions, four tigers, and one leopard) animals were diagnosed with degenerative spinal disease. Clinical signs included progressively decreased activity, moderate to severe rear limb muscle atrophy, chronic intermittent rear limb paresis, and ataxia. The age at onset of clinical signs was 10-19 yr (median = 18 yr). Radiographic evaluation of the spinal column was useful in assessing the severity of spinal lesions, and results were correlated with necropsy findings. Lesions were frequently multifocal, included intervertebral disc mineralization or herniation with collapsed intervertebral disc spaces, and were most common in the lumbar area but also involved cervical and thoracic vertebrae. Marked spondylosis was present in the cats with intervertebral disc disease, presumably subsequent to vertebral instability. Six of the animals' spinal cords were examined histologically, and five had acute or chronic damage to the spinal cord secondary to disc protrusion. Spinal disease should be suspected in geriatric large felids with decreased appetite or activity. Radiographic evaluation of the spinal column is the most useful method to assess the type and severity of spinal lesions. PMID:10884118

  16. Scapula Kinematics of Youth Baseball Players

    PubMed Central

    Oliver, Gretchen; Weimar, Wendi

    2015-01-01

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  17. Scapula Kinematics of Youth Baseball Players.

    PubMed

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  18. New Kinematical Constraints on Cosmic Acceleration

    SciTech Connect

    Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park

    2007-05-25

    We present and employ a new kinematical approach to ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t)=1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t)=j, we measure q{sub 0}=-0.81 {+-} 0.14 and j=2.16 +0.81 -0.75, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible.

  19. Circadian rhythms in handwriting kinematics and legibility.

    PubMed

    Jasper, Isabelle; Gordijn, Marijke; Häussler, Andreas; Hermsdörfer, Joachim

    2011-08-01

    The aim of the present study was to analyze the circadian rhythmicity in handwriting kinematics and legibility and to compare the performance between Dutch and German writers. Two subject groups underwent a 40 h sleep deprivation protocol under Constant Routine conditions either in Groningen (10 Dutch subjects) or in Berlin (9 German subjects). Both groups wrote every 3h a test sentence of similar structure in their native language. Kinematic handwriting performance was assessed with a digitizing tablet and evaluated by writing speed, writing fluency, and script size. Writing speed (frequency of strokes and average velocity) revealed a clear circadian rhythm, with a parallel decline during night and a minimum around 3:00 h in the morning for both groups. Script size and movement fluency did not vary with time of day in neither group. Legibility of handwriting was evaluated by intra-individually ranking handwriting specimens of the 13 sessions by 10 German and 10 Dutch raters. Whereas legibility ratings of the German handwriting specimens deteriorated during night in parallel with slower writing speed, legibility of the Dutch handwriting deteriorated not until the next morning. In conclusion, the circadian rhythm of handwriting kinematics seems to be independent of script language at least among the two tested western countries. Moreover, handwriting legibility is also subject to a circadian rhythm which, however, seems to be influenced by variations in the assessment protocol.

  20. Scapula Kinematics of Youth Baseball Players.

    PubMed

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  1. The spinal reflex cannot be perceptually separated from voluntary movements.

    PubMed

    Ghosh, Arko; Haggard, Patrick

    2014-01-01

    Both voluntary and involuntary movements activate sensors in the muscles, skin, tendon and joints. As limb movement can result from a mixture of spinal reflexes and voluntary motor commands, the cortical centres underlying conscious proprioception might either aggregate or separate the sensory inputs generated by voluntary movements from those generated by involuntary movements such as spinal reflexes. We addressed whether healthy volunteers could perceive the contribution of a spinal reflex during movements that combined both reflexive and voluntary contributions. Volunteers reported the reflexive contribution in leg movements that were partly driven by the knee-jerk reflex induced by a patellar tendon tap and partly by voluntary motor control. In one condition, participants were instructed to kick back in response to a tendon tap. The results were compared to reflexes in a resting baseline condition without voluntary movement. In a further condition, participants were instructed to kick forwards after a tap. Volunteers reported the perceived reflex contribution by repositioning the leg to the perceived maximum displacement to which the reflex moved the leg after each tendon tap. In the resting baseline condition, the reflex was accurately perceived. We found a near-unity slope of linear regressions of perceived on actual reflexive displacement. Both the slope value and the quality of regression fit in individual volunteers were significantly reduced when volunteers were instructed to generate voluntary backward kicks as soon as they detected the tap. In the kick forward condition, kinematic analysis showed continuity of reflex and voluntary movements, but the reflex contribution could be estimated from electromyography (EMG) recording on each trial. Again, participants' judgements of reflexes showed a poor relation to reflex EMG, in contrast to the baseline condition. In sum, we show that reflexes can be accurately perceived from afferent information. However

  2. Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers.

    PubMed

    Oliver, Gretchen D; Keeley, David W

    2010-12-01

    It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the pitching motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the pitching motion. However, although pelvis and torso kinematics throughout the pitching motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch. PMID:20703168

  3. Computational tool for comparison of kinematic mechanisms and commonly used kinematic models

    SciTech Connect

    Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.

    1997-03-01

    Accurate, reliable, and reproducible methods to measure the movements of human joints have been elusive. Currently, three-dimensional recording methods are used to track the motion of one segment relative to another as the joint moves. Six parameters describe the moving segment`s location and orientation relative to the reference segment: three translations (x, y, and z) and three rotations (yaw, pitch and roll) in the reference frame. The raw data can be difficult to interpret. For this reason, several methods have been developed to measure the motion of human joints and to describe the resulting data. For example, instant helical axes or screw deviation axes (Kinzell et al., 1972), the Joint Coordinate System of Grood and Suntay (1983), and the Euler angle method have been used to describe the movements of bones relative to each other. None of these methods takes into account the physical kinematic mechanism producing the joint motion. More recently, Lupichuk (1995) has developed an algorithm to find, for an arbitrary revolute, the axis` position and orientation in three- dimensional space. Each of these methods has advantages and disadvantages in analyzing joint kinematics. The authors have developed software to provide a means of comparing these methods for arbitrary, single degree of freedom, kinematic mechanisms. Our objective is to demonstrate the software and to show how it can be used to compare the results from the different kinematic models as they are applied to specific kinematic mechanisms.

  4. Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers.

    PubMed

    Oliver, Gretchen D; Keeley, David W

    2010-12-01

    It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the pitching motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the pitching motion. However, although pelvis and torso kinematics throughout the pitching motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch.

  5. Spinal Cord Stimulation and Augmentative Control Strategies for Leg Movement after Spinal Paralysis in Humans.

    PubMed

    Minassian, Karen; Hofstoetter, Ursula S

    2016-04-01

    Severe spinal cord injury is a devastating condition, tearing apart long white matter tracts and causing paralysis and disability of body functions below the lesion. But caudal to most injuries, the majority of neurons forming the distributed propriospinal system, the localized gray matter spinal interneuronal circuitry, and spinal motoneuron populations are spared. Epidural spinal cord stimulation can gain access to this neural circuitry. This review focuses on the capability of the human lumbar spinal cord to generate stereotyped motor output underlying standing and stepping, as well as full weight-bearing standing and rhythmic muscle activation during assisted treadmill stepping in paralyzed individuals in response to spinal cord stimulation. By enhancing the excitability state of the spinal circuitry, the stimulation can have an enabling effect upon otherwise "silent" translesional volitional motor control. Strategies for achieving functional movement in patients with severe injuries based on minimal translesional intentional control, task-specific proprioceptive feedback, and next-generation spinal cord stimulation systems will be reviewed. The role of spinal cord stimulation can go well beyond the immediate generation of motor output. With recently developed training paradigms, it can become a major rehabilitation approach in spinal cord injury for augmenting and steering trans- and sublesional plasticity for lasting therapeutic benefits.

  6. Spinal intradural extraosseous Ewing's sarcoma.

    PubMed

    Mateen, Farrah J; Nassar, Aziza; Bardia, Aditya; Jatoi, Aminah; Haddock, Michael G; Buckner, Jan C; Lachance, Daniel H

    2011-03-30

    Extraosseous Ewing's sarcoma (EES) involving the central nervous system is rare, but can be diagnosed and distinguished from other primitive neuroectodermal tumors (PNET) by identification of the chromosomal translocation (11;22)(q24;q12). We report EES arising from the spinal intradural extramedullary space, based on imaging, histopathological, and molecular data in two men, ages 50 and 60 years old and a review of the literature using PubMed (1970-2009). Reverse transcriptase polymerase chain reaction (RT-PCR) identified the fusion product FL1-EWS. Multimodal therapy, including radiation and alternating chemotherapy including vincristine, cyclophosphamide, doxorubicin and ifosfamide and etoposide led to local tumor control and an initial, favorable therapeutic response. No systemic involvement was seen from the time of diagnosis to the time of last follow-up (26 months) or death (4 years). This report confirms that EES is not confined to the earliest decades of life, and like its rare occurrence as an extra-axial meningeal based mass intracranially, can occasionally present as an intradural mass in the spinal canal without evidence of systemic tumor. Gross total resection followed by multimodal therapy may provide for extended progression free and overall survival.

  7. Rehabilitation of spinal cord injuries

    PubMed Central

    Nas, Kemal; Yazmalar, Levent; Şah, Volkan; Aydın, Abdulkadir; Öneş, Kadriye

    2015-01-01

    Spinal cord injury (SCI) is the injury of the spinal cord from the foramen magnum to the cauda equina which occurs as a result of compulsion, incision or contusion. The most common causes of SCI in the world are traffic accidents, gunshot injuries, knife injuries, falls and sports injuries. There is a strong relationship between functional status and whether the injury is complete or not complete, as well as the level of the injury. The results of SCI bring not only damage to independence and physical function, but also include many complications from the injury. Neurogenic bladder and bowel, urinary tract infections, pressure ulcers, orthostatic hypotension, fractures, deep vein thrombosis, spasticity, autonomic dysreflexia, pulmonary and cardiovascular problems, and depressive disorders are frequent complications after SCI. SCI leads to serious disability in the patient resulting in the loss of work, which brings psychosocial and economic problems. The treatment and rehabilitation period is long, expensive and exhausting in SCI. Whether complete or incomplete, SCI rehabilitation is a long process that requires patience and motivation of the patient and relatives. Early rehabilitation is important to prevent joint contractures and the loss of muscle strength, conservation of bone density, and to ensure normal functioning of the respiratory and digestive system. An interdisciplinary approach is essential in rehabilitation in SCI, as in the other types of rehabilitation. The team is led by a physiatrist and consists of the patients’ family, physiotherapist, occupational therapist, dietician, psychologist, speech therapist, social worker and other consultant specialists as necessary. PMID:25621206

  8. Kinematics of Haro 11: The miniature Antennae

    NASA Astrophysics Data System (ADS)

    Östlin, G.; Marquart, T.; Cumming, R. J.; Fathi, K.; Bergvall, N.; Adamo, A.; Amram, P.; Hayes, M.

    2015-11-01

    Luminous blue compact galaxies are among the most active galaxies in the local Universe in terms of their star formation rate per unit mass. They are rare at the current cosmic epoch, but were more abundant in the past and may be seen as the local analogues of higher red shift Lyman break galaxies. Studies of their kinematics is key to understanding what triggers their unusually active star formation. In this work, we investigate the kinematics of stars and ionised gas in Haro 11, one of the most luminous blue compact galaxies in the local Universe. Previous works have indicated that many of these galaxies may be triggered by galaxy mergers. We have employed Fabry-Perot interferometry, long-slit spectroscopy, and integral field unit (IFU) spectroscopy to explore the kinematics of Haro 11. We target the near-infrared calcium triplet, and use cross-correlation and penalised pixel fitting techniques to derive the stellar velocity field and velocity dispersion. We analyse ionised gas through emission lines from hydrogen, [O iii], and [S iii]. When spectral resolution and signal to noise allows, we investigate the line profile in detail and identify multiple velocity components when present. The spectra reveal a complex velocity field whose components, both stellar and gaseous, we attempt to disentangle. We find that to first order, the velocity field and velocity dispersions derived from stars and ionised gas agree. Hence the complexities reveal real dynamical disturbances providing further evidence for a merger in Haro 11. Through decomposition of emission lines, we find evidence for kinematically distinct components, for instance, a tidal arm. The ionised gas velocity field can be traced to large galactocentric radii, and shows significant velocity dispersion even far out in the halo. If interpreted as virial motions, this indicates that Haro 11 may have a mass of ~1011 M⊙. Haro 11 shows many resemblances with the famous Antennae galaxies both morphologically and

  9. The Kinematics and Dynamics of SA Galaxies

    NASA Astrophysics Data System (ADS)

    Jore, Katherine Patricia

    1997-12-01

    A study of the kinematics of the stellar and gaseous components of Sa galaxies was undertaken in order to understand the origins of the heterogeneity of the Sa galaxies as a class and to investigate previous observations suggesting that the fraction of the mass of Sa galaxies in the form of dark matter is smaller than that found in later type spirals. A sample of 23 nearby non-interacting morphologically normal galaxies was studied. The small-bulged Sa, NGC 4138, was found to contain two extended counter-rotating stellar disks. The primary stellar disk contains ~80% of the stars; the presence of Hα absorption suggests that star formation in this component ceased ~108 years ago. The remaining stars, along with the H I and emission line gas, are rotating counter to the primary disk with comparable observed velocity. The counter-rotating disk may either be the result of a merger of a spiral with a gas-rich dwarf, or the continual infall of material of opposite spin vector onto the galaxy. For the entire sample, comparison of the stellar and optical rotation curves reveals that only 4 of the 23 galaxies in the sample are free of kinematic peculiarities. Eighteen galaxies in the sample have non-circular motions along the minor axis. Along the major axis, 11 galaxies have kinematic peculiarities including extended counter-rotating stars and∨ gas, counter-rotating stellar or gas cores, or multiple stellar or gas components. The presence of kinematically decoupled components suggests that minor mergers may have been common events even among morphologically normal Sa's. Dynamical masses were obtained from the velocity fields mapped by optical and H I observations by adopting the maximum disk hypothesis. As in previous studies, the kinematics of most Sa galaxies can be modeled within the optical disk without invoking a significant dark matter halo component. However, in order to model the velocity fields as traced by the H I sizable dark matter halo components are

  10. The Stellar Kinematic Fields of NGC 3379

    NASA Astrophysics Data System (ADS)

    Statler, Thomas S.; Smecker-Hane, Tammy

    1999-02-01

    We have measured the stellar kinematic profiles of NGC 3379 along four position angles, using absorption lines in spectra obtained with the Multiple Mirror Telescope. We derive a far more detailed description of the kinematic fields through the main body of the galaxy than could be obtained from previous work. Our data extend 90" from the center, at essentially seeing-limited resolution out to 17". The derived mean velocities and dispersions have total errors (internal and systematic) better than +/-10 km s^-1, and frequently better than 5 km s^-1, out to 55". We find very weak (3 km s^-1) rotation on the minor axis interior to 12" and no detectable rotation above 6 km s^-1 from 12" to 50" or above 16 km s^-1 out to 90" (95% confidence limits). However, a Fourier reconstruction of the mean velocity field from all four sampled PAs does indicate a ~5 deg twist of the kinematic major axis, in the direction opposite to the known isophotal twist. The h_3 and h_4 parameters are found to be generally small over the entire observed region. The azimuthally averaged dispersion profile joins smoothly at large radii with the velocity dispersions of planetary nebulae. Unexpectedly, we find sharp bends in the major axis rotation curve, also visible (though less pronounced) on the diagonal position angles. The outermost bend closely coincides in position with other sharp kinematic features: an abrupt flattening of the dispersion profile, and local peaks in h_3 and h_4. All of these features are in a photometrically interesting region in which the surface brightness profile departs significantly from an r^1/4 law. Features such as these are not generally known in elliptical galaxies owing to a lack of data at comparable resolution. Very similar behavior, however, is seen the kinematics of the edge-on S0 galaxy NGC 3115. We discuss the suggestion that NGC 3379 could be a misclassified S0 galaxy; preliminary results from dynamical modeling indicate that it may be a flattened, weakly

  11. Spinal Recurrence From Intracranial Germinoma: Risk Factors and Treatment Outcome for Spinal Recurrence

    SciTech Connect

    Ogawa, Kazuhiko Yoshii, Yoshihiko; Shikama, Naoto; Nakamura, Katsumasa; Uno, Takashi; Onishi, Hiroshi; Itami, Jun; Shioyama, Yoshiyuki; Iraha, Shiro; Hyodo, Akio; Toita, Takafumi; Kakinohana, Yasumasa; Tamaki, Wakana; Ito, Hisao; Murayama, Sadayuki

    2008-12-01

    Purpose: To analyze retrospectively the risk factors of spinal recurrence in patients with intracranial germinoma and clinical outcomes of patients who developed spinal recurrence. Methods and Materials: Between 1980 and 2007, 165 patients with no evidence of spinal metastases at diagnosis were treated with cranial radiotherapy without spinal irradiation. The median follow-up in all 165 patients was 61.2 months (range, 1.2-260.1 months). Results: After the initial treatment, 15 patients (9.1%) developed spinal recurrences. Multivariate analysis revealed that large intracranial disease ({>=}4 cm) and multifocal intracranial disease were independent risk factors for spinal recurrence. Radiation field, total radiation dose, and the use of chemotherapy did not affect the occurrence of spinal recurrences. Of the 15 patients who experienced spinal recurrence, the 3-year actuarial overall survival and disease-free survival (DFS) rates from the beginning of salvage treatments were 65% and 57%, respectively. In the analysis, presence of intracranial recurrence and salvage treatment modality (radiotherapy with chemotherapy vs. radiotherapy alone) had a statistically significant impact on DFS. The 3-year DFS rate in patients with no intracranial recurrence and treated with both spinal radiotherapy and chemotherapy was 100%, whereas only 17% in patients with intracranial recurrence or treated with radiotherapy alone (p = 0.001). Conclusion: Large intracranial disease and multifocal intracranial disease were risk factors for spinal recurrence in patients with intracranial germinoma with no evidence of spinal metastases at diagnosis. For patients who developed spinal recurrence alone, salvage treatment combined with spinal radiotherapy and chemotherapy was effective in controlling the recurrent disease.

  12. Capturing three-dimensional in vivo lumbar intervertebral joint kinematics using dynamic stereo-X-ray imaging.

    PubMed

    Aiyangar, Ameet K; Zheng, Liying; Tashman, Scott; Anderst, William J; Zhang, Xudong

    2014-01-01

    small compared to the dominant motion in the sagittal plane. The demonstrated success in capturing continuous 3D in vivo lumbar intervertebral kinematics during functional tasks affords the possibility to create a baseline data set for evaluating the lumbar spinal function. The technique can be used to address the gaps in knowledge of lumbar kinematics, to improve the accuracy of the kinematic input into biomechanical models, and to support development of new disk replacement designs more closely replicating the natural lumbar biomechanics.

  13. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... column fluid space, to connect the spinal fluid to a graduated column so that the pressure can be... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device...

  14. Clinical radiology of the spine and spinal cord

    SciTech Connect

    Banna, M.

    1985-01-01

    This book is a source of information about aspects of radiology of the spine and spinal column. It presents coverage of both normal and abnormal conditions. Contents: Spinal fractures and dislocations. Degenerative diseases of the spine. Gross anatomy of the spinal cord and meninges. Intraspinal mass lesions. Spinal dysraphism. Congenital anomalies. Tumors of the vertebral column, and more.

  15. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... column fluid space, to connect the spinal fluid to a graduated column so that the pressure can be... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device...

  16. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... column fluid space, to connect the spinal fluid to a graduated column so that the pressure can be... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device...

  17. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in...

  18. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in...

  19. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in...

  20. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in...

  1. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in...

  2. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

    PubMed Central

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  3. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    PubMed

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-04-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  4. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    PubMed

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  5. [A Dumbbell-Type Thoracic Spinal Lipoma: A Case Report].

    PubMed

    Takamiya, Soichiro; Hida, Kazutoshi; Yano, Shunsuke; Sasamori, Toru; Seki, Toshitaka; Saito, Hisatoshi

    2016-06-01

    Spinal lipomas are rare, accounting for less than 1% of all spinal tumors. Most are associated with spinal dysraphism. Spinal lipomas without spinal dysraphism are uncommon;they are typically subpial tumors. Some tumors are located both inside and outside the dura mater (so-called "dumbbell-type"). Herein, we report a patient with a dumbbell-type thoracic spinal lipoma. A man in his 50's complained of progressive gait disturbance, dysesthesia in his left leg, and hyperesthesia in his right leg. His symptoms were worsened by exercise. CT and MRI revealed a thoracic spinal lipoma extending from the spinal cord to the intervertebral foramen at the Th 6-8 level. He underwent partial tumor removal and untethering. Postoperatively he reported gradual symptom abatement. Dumbbell-type spinal lipomas are very rare. Besides partial removal of the tumor, untethering should be considered when symptoms are associated with tethering of the spinal cord. PMID:27270148

  6. How realistic are flat-ramp-flat fault kinematic models? Comparing mechanical and kinematic models

    NASA Astrophysics Data System (ADS)

    Cruz, L.; Nevitt, J. M.; Hilley, G. E.; Seixas, G.

    2015-12-01

    Rock within the upper crust appears to deform according to elasto-plastic constitutive rules, but structural geologists often employ kinematic descriptions that prescribe particle motions irrespective of these physical properties. In this contribution, we examine the range of constitutive properties that are approximately implied by kinematic models by comparing predicted deformations between mechanical and kinematic models for identical fault geometric configurations. Specifically, we use the ABAQUS finite-element package to model a fault-bend-fold geometry using an elasto-plastic constitutive rule (the elastic component is linear and the plastic failure occurs according to a Mohr-Coulomb failure criterion). We varied physical properties in the mechanical model (i.e., Young's modulus, Poisson ratio, cohesion yield strength, internal friction angle, sliding friction angle) to determine the impact of each on the observed deformations, which were then compared to predictions of kinematic models parameterized with identical geometries. We found that a limited sub-set of physical properties were required to produce deformations that were similar to those predicted by the kinematic models. Specifically, mechanical models with low cohesion are required to allow the kink at the bottom of the flat-ramp geometry to remain stationary over time. Additionally, deformations produced by steep ramp geometries (30 degrees) are difficult to reconcile between the two types of models, while lower slope gradients better conform to the geometric assumptions. These physical properties may fall within the range of those observed in laboratory experiments, suggesting that particle motions predicted by kinematic models may provide an approximate representation of those produced by a physically consistent model under some circumstances.

  7. Spinal cord lesions - The rehabilitation perspective.

    PubMed

    Faria, Filipa

    2006-02-01

    The present study provides an overview of the spinal cord injury focusing mainly on aspects related to rehabilitation. Spinal cord injury affects young people in an active phase of life, determining severe handicaps. Most of the lesions are traumatic, caused by car accidents. Until fifty years ago, the survival of individuals with spinal cord injury was very reduced and the leading cause of death was renal failure. Due to developments in medical knowledge and technical advances, the survival rates have significantly improved. The causes of death have also changed being respiratory complications, particularly pneumonia, the leading causes. Immediately after a spinal cord lesion there is a phase of spinal shock which is characterized by flaccid paralysis and bladder and bowel retention. Progressively there is a return of the spinal cord automatism with the beginning of some reflex activities. Based on neurological evaluation it is pos-sible to predict motor and functional recovery and establish the rehabilitation program. We can consider three phases on the rehabilitation program: the first while the patient is still in bed, directed to prevent or treat complications due to immobility and begin sphincters reeducation; the second phase is intended to achieve wheelchair autonomy; the last phase is training in ortostatism. The rehabilitation program also comprises sports and recreational activities, psychological and social support in order to achieve an integral of the individual with a spinal cord injury.

  8. Regenerative treatment in spinal cord injury.

    PubMed

    Ozdemir, Mevci; Attar, Ayhan; Kuzu, Isinsu

    2012-09-01

    Spinal cord injury is a devastating, traumatic event, and experienced mainly among young people. Until the modern era, spinal cord injury was so rapidly fatal that no seriously injured persons would survive long enough for regeneration to occur. Treatment of spinal cord injury can be summarized as follows: prevent further cord injury, maintain blood flow, relieve spinal cord compression, and provide secure vertebral stabilization so as to allow mobilization and rehabilitation, none of which achieves functional recovery. Previous studies have focused on analyzing the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as the tissue damage and neural cell death associated with secondary injury. Now, there are hundreds of current experimental and clinical regenerative treatment studies. One of the most popular treatment method is cell transplantation in injured spinal cord. For this purpose bone marrow stromal cells, mononuclear stem cells, mesenchymal stem cells, embryonic stem cells, neural stem cells, and olfactory ensheathing cells can be used. As a result, cell transplantation has become a promising therapeutic option for spinal cord injury patients. In this paper we discuss the effectiveness of stem cell therapy in spinal cord injury.

  9. CyberKnife radiosurgery for spinal neoplasms.

    PubMed

    Gerszten, Peter C; Burton, Steven A; Ozhasoglu, Cihat

    2007-01-01

    The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. Its use for the treatment of spinal lesions has been limited by the availability of effective target immobilization and localization technologies. Conventional external beam radiotherapy lacks the precision to allow delivery of large doses of radiation near radiosensitive structures such as the spinal cord. The CyberKnife (Accuray Inc., Sunnyvale, Calif., USA) is an imageguided frameless stereotactic radiosurgery system that allows for the radiosurgical treatment of spinal lesions. The system utilizes the coupling of an orthogonal pair of X-ray cameras to a dynamically manipulated robot-mounted lightweight linear accelerator which has 6 d.f. that guides the therapy beam to the intended target without the use of frame-based fixation. Realtime imaging tracking allows for patient movement tracking with 1mm spatial accuracy. Cervical spine lesions are located and tracked relative to skull bony landmarks; lower spinal lesions are tracked relative to percutaneously placed gold fiducial bone markers. Spinal stereotactic radiosurgery using a frameless image-guided system is now both feasible and safe. The major potential benefits of radiosurgical ablation of spinal lesions are short treatment time in an outpatient setting with rapid recovery and good symptomatic response. This technique offers a successful therapeutic modality for the treatment of a variety of spinal lesions as a primary treatment or for lesions not amenable to open surgical techniques, in medically inoperable patients, lesions located in previously irradiated sites, or as an adjunct to surgery.

  10. Stance control in the chronic spinal cat.

    PubMed

    Pratt, C A; Fung, J; Macpherson, J M

    1994-05-01

    1. A longitudinal study of the control of quiet and perturbed stance was conducted before and for 1 yr after complete spinal transection (T12) in a cat trained to stand on a moveable force platform. 2. With daily training, the spinal cat recovered full weight support and some intermittent control of lateral stability within 1 mo. Within the second month postspinalization, the spinal cat achieved the ability to maintain independent, unassisted stance (no external support or stimulation) for up to 45 s during quiet stance, as well as for 62-97% of the trials of horizontal translations of the support surface. 3. Control of lateral stability in the spinal cat was severely compromised, however, as eventually the spinal cat always lost its balance. Head movements and the tendency for the hindlimbs to initiate stepping movements were more destabilizing than platform translations. 4. Our preliminary results indicate that the recovery of partial lateral stability of the hindquarters in the spinal cat is the product of passive muscle properties and segmental reflexes, which, in isolation can provide only limited balance control in the chronic spinal cat.

  11. Spinal cord evolution in early Homo.

    PubMed

    Meyer, Marc R; Haeusler, Martin

    2015-11-01

    The discovery at Nariokotome of the Homo erectus skeleton KNM-WT 15000, with a narrow spinal canal, seemed to show that this relatively large-brained hominin retained the primitive spinal cord size of African apes and that brain size expansion preceded postcranial neurological evolution. Here we compare the size and shape of the KNM-WT 15000 spinal canal with modern and fossil taxa including H. erectus from Dmanisi, Homo antecessor, the European middle Pleistocene hominins from Sima de los Huesos, and Pan troglodytes. In terms of shape and absolute and relative size of the spinal canal, we find all of the Dmanisi and most of the vertebrae of KNM-WT 15000 are within the human range of variation except for the C7, T2, and T3 of KNM-WT 15000, which are constricted, suggesting spinal stenosis. While additional fossils might definitively indicate whether H. erectus had evolved a human-like enlarged spinal canal, the evidence from the Dmanisi spinal canal and the unaffected levels of KNM-WT 15000 show that unlike Australopithecus, H. erectus had a spinal canal size and shape equivalent to that of modern humans. Subadult status is unlikely to affect our results, as spinal canal growth is complete in both individuals. We contest the notion that vertebrae yield information about respiratory control or language evolution, but suggest that, like H. antecessor and European middle Pleistocene hominins from Sima de los Huesos, early Homo possessed a postcranial neurological endowment roughly commensurate to modern humans, with implications for neurological, structural, and vascular improvements over Pan and Australopithecus. PMID:26553817

  12. Plasticity of functional connectivity in the adult spinal cord

    PubMed Central

    Cai, L.L; Courtine, G; Fong, A.J; Burdick, J.W; Roy, R.R; Edgerton, V.R

    2006-01-01

    This paper emphasizes several characteristics of the neural control of locomotion that provide opportunities for developing strategies to maximize the recovery of postural and locomotor functions after a spinal cord injury (SCI). The major points of this paper are: (i) the circuitry that controls standing and stepping is extremely malleable and reflects a continuously varying combination of neurons that are activated when executing stereotypical movements; (ii) the connectivity between neurons is more accurately perceived as a functional rather than as an anatomical phenomenon; (iii) the functional connectivity that controls standing and stepping reflects the physiological state of a given assembly of synapses, where the probability of these synaptic events is not deterministic; (iv) rather, this probability can be modulated by other factors such as pharmacological agents, epidural stimulation and/or motor training; (v) the variability observed in the kinematics of consecutive steps reflects a fundamental feature of the neural control system and (vi) machine-learning theories elucidate the need to accommodate variability in developing strategies designed to enhance motor performance by motor training using robotic devices after an SCI. PMID:16939979

  13. Advance in spinal cord ischemia reperfusion injury: Blood-spinal cord barrier and remote ischemic preconditioning.

    PubMed

    Yu, Qijing; Huang, Jinxiu; Hu, Ji; Zhu, Hongfei

    2016-06-01

    The blood-spinal cord barrier (BSCB) is the physiological and metabolic substance diffusion barrier between blood circulation and spinal cord tissues. This barrier plays a vital role in maintaining the microenvironment stability of the spinal cord. When the spinal cord is subjected to ischemia/reperfusion (I/R) injury, the structure and function of the BSCB is disrupted, further destroying the spinal cord homeostasis and ultimately leading to neurological deficit. Remote ischemic preconditioning (RIPC) is an approach in which interspersed cycles of preconditioning ischemia is followed by reperfusion to tissues/organs to protect the distant target tissues/organs against subsequent lethal ischemic injuries. RIPC is an innovation of the treatment strategies that protect the organ from I/R injury. In this study, we review the morphological structure and function of the BSCB, the injury mechanism of BSCB resulting from spinal cord I/R, and the effect of RIPC on it.

  14. Nanomedicine for Treating Spinal Cord Injury

    PubMed Central

    Tyler, Jacqueline Y.; Xu, Xiao-Ming; Cheng, Ji-Xin

    2015-01-01

    Spinal cord injury results in significant mortality and morbidity, lifestyle changes, and difficult rehabilitation. Treatment of spinal cord injury is challenging because the spinal cord is both complex to treat acutely and difficult to regenerate. Nanomaterials can be used to provide effective treatments; their unique properties can facilitate drug delivery to the injury site, enact as neuroprotective agents, or provide platforms to stimulate regrowth of damaged tissues. We review recent uses of nanomaterials including nanowires, micelles, nanoparticles, liposomes, and carbon-based nanomaterials for neuroprotection in the acute phase. We also review the design and neural regenerative application of electrospun scaffolds, conduits, and self-assembling peptide scaffolds. PMID:23945984

  15. Spinal ischemia following abdominal aortic surgery.

    PubMed

    Ferguson, L R; Bergan, J J; Conn, J; Yao, J S

    1975-03-01

    Serious spinal cord ischemia may follow infrarenal abdominal aortic surgery. Five cases are summarized and added to the 23 previously published cases in order to identify this syndrome, emphasize its importance, and draw attention to the possibility of spontaneous recovery which may occur. The multifactorial complex which comprises each patient's clinical picture clouds a precise and specific cause for paraplegia in these cases. However, neither hypotension, steal phenomena nor emboli are necessary for completion of the syndrome. The relevant spinal cord arterial anatomy indicates that the common anomalies which occur favor development of spinal cord ischemia in the arteriosclerotic population which requires aortic surgery. No means of prevention is possible at this time.

  16. Nanomedicine for treating spinal cord injury

    NASA Astrophysics Data System (ADS)

    Tyler, Jacqueline Y.; Xu, Xiao-Ming; Cheng, Ji-Xin

    2013-09-01

    Spinal cord injury results in significant mortality and morbidity, lifestyle changes, and difficult rehabilitation. Treatment of spinal cord injury is challenging because the spinal cord is both complex to treat acutely and difficult to regenerate. Nanomaterials can be used to provide effective treatments; their unique properties can facilitate drug delivery to the injury site, enact as neuroprotective agents, or provide platforms to stimulate regrowth of damaged tissues. We review recent uses of nanomaterials including nanowires, micelles, nanoparticles, liposomes, and carbon-based nanomaterials for neuroprotection in the acute phase. We also review the design and neural regenerative application of electrospun scaffolds, conduits, and self-assembling peptide scaffolds.

  17. The changing pattern of spinal arachnoiditis.

    PubMed Central

    Shaw, M D; Russell, J A; Grossart, K W

    1978-01-01

    Spinal arachnoiditis is a rare condition. Eighty cases, diagnosed during a period when 7600 spinal contrast investigations were undertaken, have been reviewed. The majority had suffered a previous spinal condition, the most common being lumbar disc disease. There has been a change in the distribution of arahnoiditis with the lumbar region now most frequently involved. This accounts for the persistence of radicular symptoms and the relatively low incidence of paraplegia when compared with earlier series. Surgery does not appear to have any role in the treatment. Images PMID:632824

  18. Microsurgical resection of intramedullary spinal cord hemangioblastoma.

    PubMed

    McCormick, Paul C

    2014-09-01

    Spinal cord hemangioblastomas account for about 10% of spinal cord tumors. They usually arise from the dorsolateral pia mater and are characterized by their significant vascularity. The principles and techniques of safe resection are different than those employed for the more commonly occurring intramedullary glial tumors (e.g. ependymoma, astrocytoma) and consist of circumferential detachment of the tumor margin from the surrounding normal pia. This video demonstrates the microsurgical techniques of resection of a thoracic spinal cord hemangioblastoma. The video can be found here: http://youtu.be/yT5KLi4VyAo. PMID:25175571

  19. Microsurgical resection of intramedullary spinal cord ependymoma.

    PubMed

    McCormick, Paul C

    2014-09-01

    Ependymomas are the most commonly occurring intramedullary spinal cord tumor in adults. With few exceptions these tumors are histologically benign, although they exhibit some biologic variability with respect to growth rate. While unencapsulated, spinal ependymomas are non-infiltrative and present a clear margin of demarcation from the surrounding spinal cord that serves as an effective dissection plane. This video demonstrates the technique of microsurgical resection of an intramedullary ependymoma through a posterior midline myelotomy. The video can be found here: http://youtu.be/lcHhymSvSqU. PMID:25175587

  20. Management of infiltrating spinal epidural angiolipoma.

    PubMed

    Nadi, Mustafa M; Nadi, Arwa M; Zabara, Mohammad Y; Ahmad, Tahani M

    2015-04-01

    Angiolipomas of the spine are rare benign tumors commonly presenting with compressive myelopathy. The present report describes a case of spinal angiolipoma with thoracic mediastinal extension in a 50-year-old woman. She presented with a long-standing history of mid-back pain with progressive lower extremities weakness. An MRI showed a heterogeneously enhancing mass located in the posterior epidural space of the thoracic spine with mediastinal extension. Histopathological examination demonstrated features consistent with spinal angiolipoma. This report emphasizes the diagnosis and therapeutic management options of infiltrating spinal angiolipomas.

  1. Management of infiltrating spinal epidural angiolipoma

    PubMed Central

    Nadi, Mustafa M.; Nadi, Arwa M.; Zabara, Mohammad Y.; Ahmad, Tahani M.

    2015-01-01

    Angiolipomas of the spine are rare benign tumors commonly presenting with compressive myelopathy. The present report describes a case of spinal angiolipoma with thoracic mediastinal extension in a 50-year-old woman. She presented with a long-standing history of mid-back pain with progressive lower extremities weakness. An MRI showed a heterogeneously enhancing mass located in the posterior epidural space of the thoracic spine with mediastinal extension. Histopathological examination demonstrated features consistent with spinal angiolipoma. This report emphasizes the diagnosis and therapeutic management options of infiltrating spinal angiolipomas. PMID:25864069

  2. Spinal Deformity Associated with Chiari Malformation.

    PubMed

    Kelly, Michael P; Guillaume, Tenner J; Lenke, Lawrence G

    2015-10-01

    Despite the frequency of Chiari-associated spinal deformities, this disease process remains poorly understood. Syringomyelia is often present; however, this is not necessary and scoliosis has been described in the absence of a syrinx. Decompression of the hindbrain is often recommended. In young patients (<10 years old) and/or those with small coronal Cobb measurements (<40°), decompression of the hindbrain may lead to resolution of the spinal deformity. Spinal fusion is reserved for those curves that progress to deformities greater than 50°. Further research is needed to understand the underlying pathophysiology to improve prognostication and treatment of this patient population.

  3. Vestibular lesion-induced developmental plasticity in spinal locomotor networks during Xenopus laevis metamorphosis.

    PubMed

    Beyeler, Anna; Rao, Guillaume; Ladepeche, Laurent; Jacques, André; Simmers, John; Le Ray, Didier

    2013-01-01

    During frog metamorphosis, the vestibular sensory system remains unchanged, while spinal motor networks undergo a massive restructuring associated with the transition from the larval to adult biomechanical system. We investigated in Xenopus laevis the impact of a pre- (tadpole stage) or post-metamorphosis (juvenile stage) unilateral labyrinthectomy (UL) on young adult swimming performance and underlying spinal locomotor circuitry. The acute disruptive effects on locomotion were similar in both tadpoles and juvenile frogs. However, animals that had metamorphosed with a preceding UL expressed restored swimming behavior at the juvenile stage, whereas animals lesioned after metamorphosis never recovered. Whilst kinematic and electrophysiological analyses of the propulsive system showed no significant differences in either juvenile group, a 3D biomechanical simulation suggested that an asymmetry in the dynamic control of posture during swimming could account for the behavioral restoration observed in animals that had been labyrinthectomized before metamorphosis. This hypothesis was subsequently supported by in vivo electromyography during free swimming and in vitro recordings from isolated brainstem/spinal cord preparations. Specifically, animals lesioned prior to metamorphosis at the larval stage exhibited an asymmetrical propulsion/posture coupling as a post-metamorphic young adult. This developmental alteration was accompanied by an ipsilesional decrease in propriospinal coordination that is normally established in strict left-right symmetry during metamorphosis in order to synchronize dorsal trunk muscle contractions with bilateral hindlimb extensions in the swimming adult. Our data thus suggest that a disequilibrium in descending vestibulospinal information during Xenopus metamorphosis leads to an altered assembly of adult spinal locomotor circuitry. This in turn enables an adaptive compensation for the dynamic postural asymmetry induced by the vestibular imbalance

  4. Vestibular Lesion-Induced Developmental Plasticity in Spinal Locomotor Networks during Xenopus laevis Metamorphosis

    PubMed Central

    Beyeler, Anna; Rao, Guillaume; Ladepeche, Laurent; Jacques, André; Simmers, John; Le Ray, Didier

    2013-01-01

    During frog metamorphosis, the vestibular sensory system remains unchanged, while spinal motor networks undergo a massive restructuring associated with the transition from the larval to adult biomechanical system. We investigated in Xenopus laevis the impact of a pre- (tadpole stage) or post-metamorphosis (juvenile stage) unilateral labyrinthectomy (UL) on young adult swimming performance and underlying spinal locomotor circuitry. The acute disruptive effects on locomotion were similar in both tadpoles and juvenile frogs. However, animals that had metamorphosed with a preceding UL expressed restored swimming behavior at the juvenile stage, whereas animals lesioned after metamorphosis never recovered. Whilst kinematic and electrophysiological analyses of the propulsive system showed no significant differences in either juvenile group, a 3D biomechanical simulation suggested that an asymmetry in the dynamic control of posture during swimming could account for the behavioral restoration observed in animals that had been labyrinthectomized before metamorphosis. This hypothesis was subsequently supported by in vivo electromyography during free swimming and in vitro recordings from isolated brainstem/spinal cord preparations. Specifically, animals lesioned prior to metamorphosis at the larval stage exhibited an asymmetrical propulsion/posture coupling as a post-metamorphic young adult. This developmental alteration was accompanied by an ipsilesional decrease in propriospinal coordination that is normally established in strict left-right symmetry during metamorphosis in order to synchronize dorsal trunk muscle contractions with bilateral hindlimb extensions in the swimming adult. Our data thus suggest that a disequilibrium in descending vestibulospinal information during Xenopus metamorphosis leads to an altered assembly of adult spinal locomotor circuitry. This in turn enables an adaptive compensation for the dynamic postural asymmetry induced by the vestibular imbalance

  5. Uncertainty Propagation in Calibration of Parallel Kinematic Machines

    SciTech Connect

    JOKIEL JR.,BERNHARD; ZIERGERT,JOHN C.

    1999-11-02

    Over the last decade, multi-axis machine tools and robots based on parallel kinematic mechanisms (PKMs) have been developed and marketed worldwide. Positional accuracy in these machines is controlled by accurate knowledge of the kinematic parameters which consists of the joint center locations and distances between joint pairs. Since these machines tend to be rather large in size, the kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. Work recently completed by the University of Florida and Sandia National Laboratories has yielded a method for determining all of the kinematic parameters of an assembled parallel kinematic device. This paper contains a brief synopsis of the calibration method created, an error budget, an uncertainty analysis for the recovered kinematic parameters and the propagation of these uncertainties to the tool tip.

  6. A Novel Algorithm for the Generation of Distinct Kinematic Chain

    NASA Astrophysics Data System (ADS)

    Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

    2016-07-01

    Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

  7. A Kinematical Approach to Dark Energy Studies

    SciTech Connect

    Rapetti, David; Allen, Steven W.; Amin, Mustafa A.; Blandford, Roger D.; /KIPAC, Menlo Park

    2006-06-06

    We present and employ a new kinematical approach to cosmological ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t) = 1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to the three best available sets of redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t) = j, we measure q{sub 0} = -0.81 {+-} 0.14 and j = 2.16{sub -0.75}{sup +0.81}, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. A standard ''dynamical'' analysis of the same data, employing the Friedmann equations and modeling the dark energy as a fluid with an equation of state parameter, w (constant), gives {Omega}{sub m} = 0.306{sub -0.040}{sup +0.042} and w = -1.15{sub -0.18}{sup +0.14}, also consistent with {Lambda}CDM at about the 1{sigma} level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible. Our results provide further interesting support for the concordance {Lambda}CDM paradigm.

  8. The Kinematics of Dwarf Carbon Stars

    NASA Astrophysics Data System (ADS)

    Plant, Kathryn A.; Margon, Bruce H.; Guhathakurta, Puragra; Rockosi, Constance M.

    2015-01-01

    The presence of molecular carbon absorption bands in the spectra of main sequence dwarfs is remarkable, as these stars have not yet evolved through the helium-burning and dredge-up phases that deposit carbon in a stellar photosphere. Dwarf carbon stars are thus generally considered members of post-mass transfer binaries, with the main sequence star polluted by an evolved, often now invisible, companion. For decades only a handful were known. Now it is recognized that carbon dwarfs likely outnumber the better-understood giant carbon stars. Green (2013) has identified more than 700 carbon dwarfs from the Sloan Digital Sky Survey (SDSS). This large sample- distributed nearly evenly throughout the SDSS footprint- makes a study of stellar kinematics possible for dwarf carbon stars as a class.We examine the proper motions and radial velocities of ~700 carbon dwarfs and compare to a sample of 2×104 non-carbon main sequence stars from the SDSS archive. The spectra of carbon dwarfs and giants can appear indistinguishable, and so the relatively faint carbon dwarfs are recognized only if they have a sufficiently large proper motion to exclude the possibility of their being distant giants. We build our non-carbon control sample by the same proper motion criteria and additionally require that the control stars match the carbon dwarf selection with respect to properties such as photometric colors. In order to examine the kinematics of a sample spread across a large portion of sky, we compare each carbon dwarf with a group of control stars separated from it by less than three degrees. Preliminary results suggest that carbon dwarfs' kinematics are similar to the distributions of their neighboring control stars. We will present the results of detailed tests, including an investigation of several carbon dwarfs with atypical radial velocities.

  9. Kinematics of transition during human accelerated sprinting

    PubMed Central

    Nagahara, Ryu; Matsubayashi, Takeo; Matsuo, Akifumi; Zushi, Koji

    2014-01-01

    ABSTRACT This study investigated kinematics of human accelerated sprinting through 50 m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG) during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed. PMID:24996923

  10. Spinal cord mensuration--a comparative study on the spinal cord segments and spinal nerves in Zambian goats.

    PubMed

    Ramkrishna, V; Lovelace, C E; Sakala, L

    1991-06-01

    It has been known that the relative length of spinal cord and its segmental volume in domestic animals has established that the dynamics of spinal cord is directly related with the functions of the limbs and in particular to their feeding habits. Bilateral rostrocaudal measurements of spinal nerves involving their root attachment length, root emergence length, interroot length, segment length and cross sectional area were recorded on the dorsal and ventral surfaces of each segment of the spinal cords of five local healthy Zambian goats. We identified that the brachial and lumbar enlargements have involved identical number of spinal cord segments. Brachial and lumbar enlargements extended from C6 to T1 and L4 to L7. The average length of spinal cord was 59.9 cm and it extended up to caudal end of 5th sacral vertebrae. The root emergence length appeared to decrease gradually from C2 segment, which remained less variable in thoracic and lumbar segments and then receded sharply through sacral segments. The dorsal nerves entered spinal cord over a greater area than ventral because of more spinal rootlets. The greatest segment length lied in mid cervical region and then from lumbar segment it decreased sharply up to the end of sacral segments. It is concluded that these goats have a feeding habit similar to that of cattle rather than resting their forelimbs on the shrubs while nibbling the leaves as recorded in Asian goats. It also confirmed that the shrubs were more drooping along with grasses in the Gwembe Valley of Zambia.

  11. Malignancies of the spinal cord.

    PubMed

    Waters, J Dawn; Peran, Encarnacion Maria Navarro; Ciacci, Joseph

    2012-01-01

    The management of intramedullary spinal cord tumors (IMSCT) is primarily concerned with the preservation of existing neurologic function. To this end, clinical scientists are continually seeking tools and techniques to improve the safety and efficacy of tumor resection and control. Further advances in safety and efficacy can be proposed at each phase of management, from pre-operative screening to post-treatment monitoring. Innovations within the areas of molecular biology and genetics, intraoperative imaging and stereotactic radiosurgery offer exciting new options to explore in the management of IMSCT. This section will review the pathophysiology and epidemiology of IMSCT and the state-of-the-art management before delving into the promising new tools and techniques for each phase of management. PMID:23281516

  12. Spinal cord injury in youth.

    PubMed

    Apple, D F; Anson, C A; Hunter, J D; Bell, R B

    1995-02-01

    To identify special characteristics of the pediatric spinal cord-injured (SCI) population, we analyzed a database of 1,770 traumatic SCI patients; 88 (5%) fell into the two pediatric subgroups: 0-12 years (n = 26) and 13-15 years (n = 62) at time of injury. Differences between age groups were identified with regard to demographics, neurologic characteristics, associated injuries and complications, and management. Mode level of bony injury was C2 in preteens, C4 in teens, and C4-C5 in adults. Scoliosis developed far more frequently in children, particularly preteens (23%), than in adults (5%). Violent etiologies, predominantly gunshots, accounted for a disproportionate share of injuries to preteens (19%) and African-Americans (28%), as compared with adults (12%) and Caucasians (7%). This last finding underscores the urgent need to mount a response to the nationwide proliferation of gunshot-related SCI in children and minorities.

  13. Spinal cord injury in youth.

    PubMed

    Apple, D F; Anson, C A; Hunter, J D; Bell, R B

    1995-02-01

    To identify special characteristics of the pediatric spinal cord-injured (SCI) population, we analyzed a database of 1,770 traumatic SCI patients; 88 (5%) fell into the two pediatric subgroups: 0-12 years (n = 26) and 13-15 years (n = 62) at time of injury. Differences between age groups were identified with regard to demographics, neurologic characteristics, associated injuries and complications, and management. Mode level of bony injury was C2 in preteens, C4 in teens, and C4-C5 in adults. Scoliosis developed far more frequently in children, particularly preteens (23%), than in adults (5%). Violent etiologies, predominantly gunshots, accounted for a disproportionate share of injuries to preteens (19%) and African-Americans (28%), as compared with adults (12%) and Caucasians (7%). This last finding underscores the urgent need to mount a response to the nationwide proliferation of gunshot-related SCI in children and minorities. PMID:7729113

  14. Kinematics and Fluid Dynamics of Jellyfish Maneuvering

    NASA Astrophysics Data System (ADS)

    Miller, Laura; Hoover, Alex

    2014-11-01

    Jellyfish propel themselves through the water through periodic contractions of their elastic bells. Some jellyfish, such as the moon jellyfish Aurelia aurita and the upside down jellyfish Cassiopea xamachana, can perform turns via asymmetric contractions of the bell. The fluid dynamics of jellyfish forward propulsion and turning is explored here by analyzing the contraction kinematics of several species and using flow visualization to quantify the resulting flow fields. The asymmetric contraction and structure of the jellyfish generates asymmetries in the starting and stopping vortices. This creates a diagonal jet and a net torque acting on the jellyfish. Results are compared to immersed boundary simulations

  15. Quantum simulation of noncausal kinematic transformations.

    PubMed

    Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E

    2013-08-30

    We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system. PMID:24033011

  16. Kinematic Measurements from YouTube Videos

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.

    2009-04-01

    Video analysis of motion has been in use now for some time.1-3 However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers. This paper provides examples such as measuring the average speed of a winning horse at the Kentucky Derby, plotting speed versus time from watching the speedometer of a high-performance bike, and determining acceleration for circular motion of amusement park rides.

  17. JFKengine: A Jacobian and Forward Kinematics Generator

    SciTech Connect

    Fischer, K.N.

    2003-02-13

    During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific goal of this project is

  18. Kinematic Dynamo In Turbulent Circumstellar Disks

    NASA Technical Reports Server (NTRS)

    Stepinski, T.

    1993-01-01

    Many circumstellar disks associated with objects ranging from protoplanetary nebulae, to accretion disks around compact stars allow for the generation of magnetic fields by an (alpha)omega dynamo. We have applied kinematic dynamo formalism to geometrically thin accretion disks. We calculate, in the framework of an adiabatic approximation, the normal mode solutions for dynamos operating in disks around compact stars. We then describe the criteria for a viable dynamo in protoplanetary nebulae, and discuss the particular features that make accretion disk dynamos different from planetary, stellar, and galactic dynamos.

  19. Mapping Dark Matter Halos with Stellar Kinematics

    NASA Astrophysics Data System (ADS)

    Murphy, Jeremy; Gebhardt, K.; Greene, J. E.; Graves, G.

    2013-07-01

    Galaxies of all sizes form and evolve in the centers of dark matter halos. As these halos constitute the large majority of the total mass of a galaxy, dark matter certainly plays a central role in the galaxy's formation and evolution. Yet despite our understanding of the importance of dark matter, observations of the extent and shape of dark matter halos have been slow in coming. The paucity of data is particularly acute in elliptical galaxies. Happily, concerted effort over the past several years by a number of groups has been shedding light on the dark matter halos around galaxies over a wide range in mass. The development of new instrumentation and large surveys, coupled with the tantalizing evidence for a direct detection of dark matter from the AMS experiment, has brought on a golden age in the study of galactic scale dark matter halos. I report on results using extended stellar kinematics from integrated light to dynamically model massive elliptical galaxies in the local universe. I use the integral field power of the Mitchell Spectrograph to explore the kinematics of stars to large radii (R > 2.5 r_e). Once the line-of-sight stellar kinematics are measured, I employ orbit-based, axisymmetric dynamical modeling to explore a range of dark matter halo parameterizations. Globular cluster kinematics at even larger radii are used to further constrain the dynamical models. The dynamical models also return information on the anisotropy of the stars which help to further illuminate the primary formation mechanisms of the galaxy. Specifically, I will show dynamical modeling results for the first and second rank galaxies in the Virgo Cluster, M49 and M87. Although similar in total luminosity and ellipticity, these two galaxies show evidence for different dark matter halo shapes, baryon to dark matter fractions, and stellar anisotropy profiles. Moreover, the stellar velocity dispersion at large radii in M87 is significantly higher than the globular clusters at the same

  20. Quantum simulation of noncausal kinematic transformations.

    PubMed

    Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E

    2013-08-30

    We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system.

  1. Automobile Collisions, Kinematics and Related Injury Patterns

    PubMed Central

    Siegel, A. W.

    1972-01-01

    It has been determined clinically that fatalities and injury severity resulting from automobile collisions have decreased during the last five years for low impact speeds. This reduction is a direct result of the application of biomechanics and occupant kinematics, as well as changes in automobile design. The paper defines terminology used in the field of mechanics and develops examples and illustrations of the physical concepts of acceleration, force strength, magnitude duration, rate of onset and others, as they apply to collision phenomena and injury. The mechanism of injury pattern reduction through the use of restraint systems is illustrated. PMID:5059661

  2. TWIK-Related Spinal Cord K+ Channel Expression Is Increased in the Spinal Dorsal Horn after Spinal Nerve Ligation

    PubMed Central

    Hwang, Hee Youn; Zhang, Enji; Park, Sangil; Chung, Woosuk; Lee, Sunyeul; Kim, Dong Woon

    2015-01-01

    Purpose The TWIK-related spinal cord K+ channel (TRESK) has recently been discovered and plays an important role in nociceptor excitability in the pain pathway. Because there have been no reports on the TRESK expression or its function in the dorsal horn of the spinal cord in neuropathic pain, we analyzed TRESK expression in the spinal dorsal horn in a spinal nerve ligation (SNL) model. Materials and Methods We established a SNL mouse model by using the L5-6 spinal nerves ligation. We used real-time polymerase chain reaction and immunohistochemistry to investigate TRESK expression in the dorsal horn and L5 dorsal rot ganglion (DRG). Results The SNL group showed significantly higher expression of TRESK in the ipsilateral dorsal horn under pain, but low expression in L5 DRG. Double immunofluorescence staining revealed that immunoreactivity of TRESK was mostly restricted in neuronal cells, and that synapse markers GAD67 and VGlut2 appeared to be associated with TRESK expression. We were unable to find a significant association between TRESK and calcineurin by double immunofluorescence. Conclusion TRESK in spinal cord neurons may contribute to the development of neuropathic pain following injury. PMID:26256973

  3. Advanced noninvasive imaging of spinal vascular malformations

    PubMed Central

    Eddleman, Christopher S.; Jeong, Hyun; Cashen, Ty A.; Walker, Matthew; Bendok, Bernard R.; Batjer, H. Hunt; Carroll, Timothy J.

    2010-01-01

    Spinal vascular malformations (SVMs) are an uncommon, heterogeneous group of vascular anomalies that can render devastating neurological consequences if they are not diagnosed and treated in a timely fashion. Imaging SVMs has always presented a formidable challenge because their clinical and imaging presentations resemble those of neoplasms, demyelination diseases, and infection. Advancements in noninvasive imaging modalities (MR and CT angiography) have increased during the last decade and have improved the ability to accurately diagnose spinal vascular anomalies. In addition, intraoperative imaging techniques have been developed that aid in the intraoperative assessment before, during, and after resection of these lesions with minimal and/or optimal use of spinal digital subtraction angiography. In this report, the authors review recent advancements in the imaging of SVMs that will likely lead to more timely diagnoses and treatment while reducing procedural risk exposure to the patients who harbor these uncommon spinal lesions. PMID:19119895

  4. Brain and Spinal Tumors: Hope through Research

    MedlinePlus

    ... of the CNS. Some tools used in the operating room include a surgical microscope, the endoscope (a ... cells, which support other brain function. central nervous system (CNS)—the brain and spinal cord. cerebrospinal fluid ( ...

  5. Spinal cord protection in aortic endovascular surgery.

    PubMed

    Scott, D A; Denton, M J

    2016-09-01

    A persistent neurological deficit, such as paraplegia or paraparesis, secondary to spinal cord injury remains one of the most feared complications of surgery on the descending thoracic or abdominal aorta. This is despite sophisticated advances in imaging and the use of less invasive endovascular procedures. Extensive fenestrated endovascular aortic graft prostheses still carry a risk of spinal cord injury of up to 10%; thus, this risk should be identified and strategies implemented to protect the spinal cord and maintain perfusion. The patients at highest risk are those undergoing extensive thoracic aortic stenting including thoracic, abdominal, and pelvic vessels. Although many techniques are available, lumbar cerebrospinal fluid drainage remains the most frequent intervention, along with maintenance of perfusion pressure and possibly staged procedures to allow collateral vessel stabilization. Many questions remain regarding other technical aspects, spinal cord monitoring and cooling, pharmacological protection, and the optimal duration of interventions into the postoperative period. PMID:27566805

  6. Spinal Cord Injury: Hope through Research

    MedlinePlus

    ... chronic pain in people with spinal cord injury. Robotic-assisted therapy Most recovery following SCI takes place ... the safety and efficacy of a type of robotic therapy device known as the AMES device. The ...

  7. Simulation and resident education in spinal neurosurgery

    PubMed Central

    Bohm, Parker E.; Arnold, Paul M.

    2015-01-01

    Background: A host of factors have contributed to the increasing use of simulation in neurosurgical resident education. Although the number of simulation-related publications has increased exponentially over the past two decades, no studies have specifically examined the role of simulation in resident education in spinal neurosurgery. Methods: We performed a structured search of several databases to identify articles detailing the use of simulation in spinal neurosurgery education in an attempt to catalogue potential applications for its use. Results: A brief history of simulation in medicine is given, followed by current trends of spinal simulation utilization in residency programs. General themes from the literature are identified that are integral for implementing simulation into neurosurgical residency curriculum. Finally, various applications are reported. Conclusion: The use of simulation in spinal neurosurgery education is not as ubiquitous in comparison to other neurosurgical subspecialties, but many promising methods of simulation are available for augmenting resident education. PMID:25745588

  8. Brain and Spinal Cord Tumors in Adults

    MedlinePlus

    ... saved articles window. My Saved Articles » My ACS » Brain and Spinal Cord Tumors in Adults Download Printable ... the topics below to get started. What Is Brain/CNS Tumors In Adults? What are adult brain ...

  9. Spinal Cord Injury Model System Information Network

    MedlinePlus

    ... the UAB-SCIMS More The UAB-SCIMS Information Network The University of Alabama at Birmingham Spinal Cord Injury Model System (UAB-SCIMS) maintains this Information Network as a resource to promote knowledge in the ...

  10. Spinal canal surrogate for testing intradural implants.

    PubMed

    Oya, H; Howard, M A; Shurig, R; Gillies, G T

    2012-11-01

    We have designed, built and tested an anthropomorphic-scale surrogate spinal canal, for use in preliminary evaluations of the performance characteristics of a novel intradural spinal cord stimulator. The surrogate employs a silicone mock spinal cord with semi-major and semi-minor diameters of 10 and 6 mm, respectively, commensurate with those of actual thoracic-level spinal cord. The axial restoring force provided by the 300 µm thick silicone denticulate ligament constructs on the mock cord is ~ 0.32 N mm(-1) over a 1.5 mm range of displacement, which is within a factor of 2 of that measured by others in human cadaver specimens. Examples of testing protocols of prototype intradural stimulators that employ this device are discussed. PMID:22953718

  11. Unusual aetiology of malignant spinal cord compression.

    PubMed

    Boland, Jason; Rennick, Adrienne

    2013-06-01

    Malignant spinal cord compression (MSCC) is an oncological emergency requiring rapid diagnosis and treatment to prevent irreversible spinal cord injury and disability. A case is described in a 45-year-old male with renal cell carcinoma in which the presentation of the MSCC was atypical with principally proximal left leg weakness with no evidence of bone metastasis. This was due to an unusual aetiology of the MSCC as the renal carcinoma had metastasised to his left psoas muscle causing a lumbosacral plexopathy and infiltrated through the intervertebral disc spaces, initially causing left lateral cauda equina and upper lumbar cord compression, before complete spinal cord compression. This case illustrates the varied aetiology of MSCC and reinforces the importance of maintaining a high index of suspicion of the possibility of spinal cord compression. PMID:24644568

  12. Investigation of spinal pathology in notalgia paresthetica.

    PubMed

    Savk, Oner; Savk, Ekin

    2005-06-01

    A possible association of spinal pathology with notalgia paresthetica (NP) was investigated through clinical and radiographic evaluation. Forty-three NP patients underwent dermatologic and orthopedic examination accompanied by radiography of the spine. Sixty-one lesions in 43 patients were evaluated. In 34 patients, various vertebral pathologies were observed radiographically by a blinded investigator, and in 28 of these cases these changes were most prominent in the vertebrae which corresponded to a lesional dermatome. Thirty-seven lesions were accompanied by spinal changes decided to be relevant (60.7%). The striking correlation of NP localization with spinal pathology suggests that spinal nerve impingement may contribute to the pathogenesis of this entity. PMID:15928634

  13. Staging Childhood Brain and Spinal Cord Tumors

    MedlinePlus

    ... before the cancer is diagnosed and continue for months or years. Childhood brain and spinal cord tumors ... after treatment. Some cancer treatments cause side effects months or years after treatment has ended. These are ...

  14. Geometric deviation modeling by kinematic matrix based on Lagrangian coordinate

    NASA Astrophysics Data System (ADS)

    Liu, Weidong; Hu, Yueming; Liu, Yu; Dai, Wanyi

    2015-09-01

    Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric variation and gesture variation of multi-rigid body is not included. In this paper, a kinematic matrix model based on Lagrangian coordinate is introduced, with the purpose of unified model for geometric variation and gesture variation and their interactive and integrated analysis. Kinematic model with joint, local base and movable base is built. The ideal feature of functional geometry is treated as the base body; the fitting feature of functional geometry is treated as the adjacent movable body; the local base of the kinematic model is fixed onto the ideal geometry, and the movable base of the kinematic model is fixed onto the fitting geometry. Furthermore, the geometric deviation is treated as relative location or rotation variation between the movable base and the local base, and it's expressed by the Lagrangian coordinate. Moreover, kinematic matrix based on Lagrangian coordinate for different types of geometry tolerance zones is constructed, and total freedom for each kinematic model is discussed. Finally, the Lagrangian coordinate library, kinematic matrix library for geometric deviation modeling is illustrated, and an example of block and piston fits is introduced. Dimension and geometric tolerances of the shaft and hole fitting feature are constructed by kinematic matrix and Lagrangian coordinate, and the results indicate that the proposed kinematic matrix is capable and robust in dimension and geometric tolerances modeling.

  15. Kinematics Analysis of an Aided Robot for Needle Insertion

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Gao, Dedong; Wang, Shan; Bai, Huiquan; Zheng, Haojun

    The kinematic relationship between the needle base and the robot's joints is analyzed. The analysis process is based on the aided needle-insertion robot built by our group. The thinking of needle-inserting procedure is confirming the needle base's posture before the needle inserted into tissue. The method of Denavit-Hartenberg (D-H) parameters is used to establish a link robot body-frames with the structural characteristics of the robot. After analysing kinematics, the kinematics equation is presented. The kinematics inverse solutions are obtained with the analytical method and geometry analysis method.

  16. Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation

    PubMed Central

    Yue, James J.; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

    2008-01-01

    Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ® L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISOinitial = 2.7 ± 0.3 mg/million cycles. During the ASTM test period (10–15 million cycles) a gravimetric wear rate of 0.14 ± 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar

  17. Radiosurgery of Spinal Meningiomas and Schwannomas

    PubMed Central

    Kufeld, M.; Wowra, B.; Muacevic, A.; Zausinger, Stefan; Tonn, Jörg-Christian

    2012-01-01

    Purpose of this study is to analyze local control, clinical symptoms and toxicity after image-guided radiosurgery of spinal meningiomas and schwannomas. Standard treatment of benign spinal lesions is microsurgical resection. While a few publications have reported about radiosurgery for benign spinal lesions, this is the first study analyzing the outcome of robotic radiosurgery for benign spinal tumors, treated exclusively with a non-invasive, fiducial free, single-fraction setup. Thirty-six patients with spinal meningiomas or schwannomas were treated, utilizing a robotic radiosurgery system (CyberKnife®, Accuray Inc. Sunnyvale CA), and were followed prospectively. Medical history, histology, clinical symptoms and radiographic outcome were recorded. Thirty-nine spinal lesions were treated because of tumor recurrence, remnants after microsurgery, multiple lesions, or rejection of open surgery. Median age was 45 years (range 18–80 years). Median target volume was 3.4 cm3 (range 0.2–43.4 cm3). Histology revealed 28 schwannomas and 11 meningiomas (WHO grade I). All spinal levels were affected. Median prescription dose was 14 Gray (95% C.I. 13.4–14 Gy) to the 70% isodose. After a median follow-up of 18 months (range 6–50 months) no local tumor progression was detected. 20 lesions (51%) remained stable, 19 tumors (49%) decreased in size. One patient with schwannomatosis was treated repeatedly for three new tumor locations. Pain was the initial symptom in 16 of 25 schwannoma patients, and in 3 of 11 patients with meningiomas. Pain levels decreased in 8/19 patients. All but one patient with motor deficits remained clinically stable. No myelopathic signs where found. Single-session radiosurgery for benign spinal tumors in selected patients has proven to inhibit tumor progression within the observed period without signs of early toxicity. Radiosurgery offers an additional treatment option, if microsurgery is not feasible in cases of tumor recurrence, post

  18. Extradural spinal meningioma: Revisiting a rare entity

    PubMed Central

    Bettaswamy, Guruprasad; Ambesh, Paurush; Das, Kuntal Kanti; Sahu, Rabi; Srivastava, Arun; Mehrotra, Anant; Jaiswal, Awadhesh; Jaiswal, Sushila; Behari, Sanjay

    2016-01-01

    Spinal meningiomas are mostly intradural in location although at times these are associated with some extradural extensions. Purely extradural spinal meningiomas (EDSMs) are however, extremely rare and when present, may cause diagnostic dilemma preoperatively. Only seven cases of pure EDSM have been reported till date. In this paper, we describe two cases of EDSM affecting the cervical spine and present their clinical profiles, radiological findings, operative management, and follow-up data, along with a review of the literature. PMID:27041890

  19. Spinal muscular atrophy, John Griffin, and mentorship.

    PubMed

    Sumner, Charlotte J

    2012-12-01

    Hereditary canine spinal muscular atrophy is an inherited motor neuron disease that occurs in Brittany Spaniels and has remarkable similarities with human spinal muscular atrophy. Both disorders are characterized by proximal limb and truncal muscle weakness of variable severity. Detailed pathological studies indicate that there is early dysfunction of motor neuron synapses, particularly the neuromuscular junction synapse, prior to motor neuron death. This period of synaptic dysfunction may define a critical window of opportunity for disease reversibility in motor neuron disease.

  20. Segmentation of the human spinal cord.

    PubMed

    De Leener, Benjamin; Taso, Manuel; Cohen-Adad, Julien; Callot, Virginie

    2016-04-01

    Segmenting the spinal cord contour is a necessary step for quantifying spinal cord atrophy in various diseases. Delineating gray matter (GM) and white matter (WM) is also useful for quantifying GM atrophy or for extracting multiparametric MRI metrics into specific WM tracts. Spinal cord segmentation in clinical research is not as developed as brain segmentation, however with the substantial improvement of MR sequences adapted to spinal cord MR investigations, the field of spinal cord MR segmentation has advanced greatly within the last decade. Segmentation techniques with variable accuracy and degree of complexity have been developed and reported in the literature. In this paper, we review some of the existing methods for cord and WM/GM segmentation, including intensity-based, surface-based, and image-based methods. We also provide recommendations for validating spinal cord segmentation techniques, as it is important to understand the intrinsic characteristics of the methods and to evaluate their performance and limitations. Lastly, we illustrate some applications in the healthy and pathological spinal cord. One conclusion of this review is that robust and automatic segmentation is clinically relevant, as it would allow for longitudinal and group studies free from user bias as well as reproducible multicentric studies in large populations, thereby helping to further our understanding of the spinal cord pathophysiology and to develop new criteria for early detection of subclinical evolution for prognosis prediction and for patient management. Another conclusion is that at the present time, no single method adequately segments the cord and its substructure in all the cases encountered (abnormal intensities, loss of contrast, deformation of the cord, etc.). A combination of different approaches is thus advised for future developments, along with the introduction of probabilistic shape models. Maturation of standardized frameworks, multiplatform availability, inclusion

  1. Mediastinal paraganglioma causing spinal cord compression.

    PubMed Central

    Reyes, M G; Fresco, R; Bruetman, M E

    1977-01-01

    An invasive paraganglioma of the posterior mediastinum caused spinal cord compression in a 31 year old women. Electron microscopic examination of the paraganglioma invading the epidural space revealed numerous dense-cored granules in the cytoplasm of the tumour cells. We are reporting this case to present the ultrastructure of mediastinal paraganglioma, and to call attention to an unusual cause of spinal cord compression. Images PMID:886352

  2. APOGEE Kinematics. I. Overview of the Kinematics of the Galactic Bulge as Mapped By APOGEE

    NASA Astrophysics Data System (ADS)

    Ness, M.; Zasowski, G.; Johnson, J. A.; Athanassoula, E.; Majewski, S. R.; García Pérez, A. E.; Bird, J.; Nidever, D.; Schneider, Donald P.; Sobeck, J.; Frinchaboy, P.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey

    2016-03-01

    We present the stellar kinematics across the Galactic bulge and into the disk at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the Milky Way. APOGEE includes extensive coverage of the stellar populations of the bulge along the midplane and near-plane regions. From these data, we have produced kinematic maps of 10,000 stars across longitudes of 0° < l < 65°, and primarily across latitudes of | b| < 5° in the bulge region. The APOGEE data reveal that the bulge is cylindrically rotating across all latitudes and is kinematically hottest at the very center of the bulge, with the smallest gradients in both kinematic and chemical space inside the innermost region (| l,b| ) < (5°, 5°). The results from APOGEE show good agreement with data from other surveys at higher latitudes and a remarkable similarity to the rotation and dispersion maps of barred galaxies viewed edge-on. The thin bar that is reported to be present in the inner disk within a narrow latitude range of | b| < 2° appears to have a corresponding signature in [{Fe}/{{H}}] and [α /{Fe}]. Stars with [{Fe}/{{H}}] > -0.5 have dispersion and rotation profiles that are similar to that of N-body models of boxy/peanut bulges. There is a smooth kinematic transition from the thin bar and boxy bulge (l,| b| ) < (15°, 12°) out to the disk for stars with [{Fe}/{{H}}] > -1.0, and the chemodynamics across (l, b) suggests that the stars in the inner Galaxy with [{Fe}/{{H}}] > -1.0 originate in the disk.

  3. Kinematic GPS Profiles to monitor surface deformation

    NASA Astrophysics Data System (ADS)

    Charara, R.; Vigny, C.; Briole, P.

    2008-12-01

    GPS kinematic measurement consists in placing a GPS rover receiver that registers its position on a moving vehicule with a high frequency. The frequency of the data acquisition is chosen according to the number of points and the precision needed to characterize the rover trajectory. The position of the rover receiver can be determined with respect to another GPS reference station with a precision of a few centimeters. Consequently different kinematic profiles on trajectories can be realized in different contexts (volcano slopes, active faults,...). We first studied the correlation between different profiles on the same trajectory in the absense of any particular event. Then different individual profiles are interpolated and a single profiles is generated which we refer to as "tube". We also studied and analyzed the impact of different parameters such as the baseline length, the atmospheric errors and the number of individual profiles on the precision of the obtained tube. We present results of experimentations that were performed in Chili, Reunion Island and Greece and we show how the results can be influenced by the baselines lengths and topographies. In case of event (Earthquakes, volcanoes eruptions, landslides,...) this technique can be used to assess the amplitude of ground deformation. We estimate the thresholds (in term of amplitude and spatial extension) of detectable signals.

  4. Kinematics and Aerodynamics of Backward Flying Dragonflies

    NASA Astrophysics Data System (ADS)

    Bode-Oke, Ayodeji; Zeyghami, Samane; Dong, Haibo

    2015-11-01

    Highly maneuverable insects such as dragonflies have a wide range of flight capabilities; precise hovering, fast body reorientations, sideways flight and backward takeoff are only a few to mention. In this research, we closely examined the kinematics as well as aerodynamics of backward takeoff in dragonflies and compared them to those of forward takeoff. High speed videography and accurate 3D surface reconstruction techniques were employed to extract details of the wing and body motions as well as deformations during both flight modes. While the velocities of both forward and backward flights were similar, the body orientation as well as the wing kinematics showed large differences. Our results indicate that by tilting the stroke plane angle of the wings as well as changing the orientation of the body relative to the flight path, dragonflies control the direction of the flight like a helicopter. In addition, our detailed analysis of the flow in these flights shows important differences in the wake capture phenomena among these flight modes. This work is supported by NSF CBET-1313217.

  5. Bayesian Kinematic Finite Fault Source Models (Invited)

    NASA Astrophysics Data System (ADS)

    Minson, S. E.; Simons, M.; Beck, J. L.

    2010-12-01

    Finite fault earthquake source models are inherently under-determined: there is no unique solution to the inverse problem of determining the rupture history at depth as a function of time and space when our data are only limited observations at the Earth's surface. Traditional inverse techniques rely on model constraints and regularization to generate one model from the possibly broad space of all possible solutions. However, Bayesian methods allow us to determine the ensemble of all possible source models which are consistent with the data and our a priori assumptions about the physics of the earthquake source. Until now, Bayesian techniques have been of limited utility because they are computationally intractable for problems with as many free parameters as kinematic finite fault models. We have developed a methodology called Cascading Adaptive Tempered Metropolis In Parallel (CATMIP) which allows us to sample very high-dimensional problems in a parallel computing framework. The CATMIP algorithm combines elements of simulated annealing and genetic algorithms with the Metropolis algorithm to dynamically optimize the algorithm's efficiency as it runs. We will present synthetic performance tests of finite fault models made with this methodology as well as a kinematic source model for the 2007 Mw 7.7 Tocopilla, Chile earthquake. This earthquake was well recorded by multiple ascending and descending interferograms and a network of high-rate GPS stations whose records can be used as near-field seismograms.

  6. THE KINEMATICS OF PRIMATE MIDFOOT FLEXIBILITY

    PubMed Central

    Greiner, Thomas M.; Ball, Kevin A.

    2015-01-01

    This study describes a unique assessment of primate intrinsic foot joint kinematics based upon bone pin rigid cluster tracking. It challenges the assumption that human evolution resulted in a reduction of midfoot flexibility, which has been identified in other primates as the “midtarsal break.” Rigid cluster pins were inserted into the foot bones of human, chimpanzee, baboon and macaque cadavers. The positions of these bone pins were monitored during a plantarflexion-dorsiflexion movement cycle. Analysis resolved flexion-extension movement patterns and the associated orientation of rotational axes for the talonavicular, calcaneocuboid and lateral cubometatarsal joints. Results show that midfoot flexibility occurs primarily at the talonavicular and cubometatarsal joints. The rotational magnitudes are roughly similar between humans and chimps. There is also a similarity among evaluated primates in the observed rotations of the lateral cubometatarsal joint, but there was much greater rotation observed for the talonavicular joint, which may serve to differentiate monkeys from the hominines. It appears that the capability for a midtarsal break is present within the human foot. A consideration of the joint axes shows that the medial and lateral joints have opposing orientations, which has been associated with a rigid locking mechanism in the human foot. However, the potential for this same mechanism also appears in the chimpanzee foot. These findings demonstrate a functional similarity within the midfoot of the hominines. Therefore, the kinematic capabilities and restrictions for the skeletal linkages of the human foot may not be as unique as has been previously suggested. PMID:25234343

  7. The Kinematics of Turbulent Boundary Layer Structure

    NASA Technical Reports Server (NTRS)

    Robinson, Stephen Kern

    1991-01-01

    The long history of research into the internal structure of turbulent boundary layers has not provided a unified picture of the physics responsible for turbulence production and dissipation. The goals of the present research are to: (1) define the current state of boundary layer structure knowledge; and (2) utilize direct numerical simulation results to help close the unresolved issues identified in part A and to unify the fragmented knowledge of various coherent motions into a consistent kinematic model of boundary layer structure. The results of the current study show that all classes of coherent motion in the low Reynolds number turbulent boundary layer may be related to vortical structures, but that no single form of vortex is representative of the wide variety of vortical structures observed. In particular, ejection and sweep motions, as well as entrainment from the free-streem are shown to have strong spatial and temporal relationships with vortical structures. Disturbances of vortex size, location, and intensity show that quasi-streamwise vortices dominate the buffer region, while transverse vortices and vortical arches dominate the wake region. Both types of vortical structure are common in the log region. The interrelationships between the various structures and the population distributions of vortices are combined into a conceptual kinematic model for the boundary layer. Aspects of vortical structure dynamics are also postulated, based on time-sequence animations of the numerically simulated flow.

  8. Nuclear Rings in Galaxies - A Kinematic Perspective

    NASA Technical Reports Server (NTRS)

    Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain

    2011-01-01

    We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the rings and those of their host galaxies, indicate the rings are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear rings reside. We find that there is evidence of a correlation between compactness and ring width and size. Radially wide rings are less compact, and thus have lower mass concentration. The compactness increases as the ring width decreases. We also find that the nuclear ring size is dependent on the bar strength, with weaker bars allowing rings of any size to form.

  9. Flapping flight: effect of asymmetric kinematics

    NASA Astrophysics Data System (ADS)

    Pande, Nakul; Krithivasan, Siddharth; K. R., Sreenivas

    2014-11-01

    Flapping flight has received considerable attention in the past with its relevance in the design of micro-air vehicles. In this regard, asymmetric flapping of wings offers simple kinematics. Nevertheless, it leads to symmetry-breaking in the flow field and generation of sustained lift. It has been observed previously with flow visualization experiments and Discrete Vortex Method (DVM) simulations that if the down-stroke time period is lesser than the up-stroke time, there is a net downward momentum imparted to the fluid. This is seen as a switching the flow field from a four-jet (symmetric) to a two-jet (asymmetric) configuration when the stroke-time ratio is progressively varied. This symmetry breaking has been studied experimentally using Particle Image Velocimetry (PIV) across a range of Reynolds Numbers and asymmetry ratios. Results are also corroborated with results from 3-D numerical simulations. Study helps in shedding light on the effectiveness of asymmetric kinematics as a lift generation mechanism.

  10. Feeding kinematics of phyllomedusine tree frogs.

    PubMed

    Gray, L A; Nishikawa, K C

    1995-02-01

    Previous studies have demonstrated that the phyllomedusine hylids possess highly protrusible tongues, a derived characteristic within the family Hylidae. In the present study, the kinematics of the feeding behavior of a phyllomedusine species, Pachymedusa dacnicolor, was analyzed using high-speed video (180 frames s-1). Its behavior was compared with that of Hyla cinerea, a species with a weakly protrusible tongue. P. dacnicolor exhibits a faster rate of tongue protraction, a longer gape cycle and more variable feeding kinematics than H. cinerea. In addition, the tongue is used in a unique 'fly-swatter' fashion, to pin the prey to the substratum as the frog completes the lunge. The rapid tongue protraction, extended gape cycle and fly-swatter action may have evolved in response to a diet of large, rapidly moving insects. In addition, several duration variables of the feeding cycle were greater for misses than for captures and drops, which suggests that sensory feedback rather than biomechanics controls gape cycle duration.

  11. Kinematics of unconstrained tactile texture exploration.

    PubMed

    Callier, Thierri; Saal, Hannes P; Davis-Berg, Elizabeth C; Bensmaia, Sliman J

    2015-04-01

    A hallmark of tactile texture exploration is that it involves movement between skin and surface. When we scan a surface, small texture-specific vibrations are produced in the skin, and specialized cutaneous mechanoreceptors convert these vibrations into highly repeatable, precise, and informative temporal spiking patterns in tactile afferents. Both texture-elicited vibrations and afferent responses are highly dependent on exploratory kinematics, however; indeed, these dilate or contract systematically with decreases or increases in scanning speed, respectively. These profound changes in the peripheral response that accompany changes in scanning speed and other parameters of texture scanning raise the question as to whether exploratory behaviors change depending on what surface is explored or what information is sought about that surface. To address this question, we measure and analyze the kinematics as subjects explore textured surfaces to evaluate different types of texture information, namely the textures' roughness, hardness, and slipperiness. We find that the exploratory movements are dependent both on the perceptual task, as has been previously shown, but also on the texture that is scanned. We discuss the implications of our findings regarding the neural coding and perception of texture. PMID:25744883

  12. Gait kinematic analysis evaluates hindlimb revascularization.

    PubMed

    Ríos, Amelia; Delgado, Alexandra; Escalante, Bruno; Santana, Jesús

    2011-01-01

    Peripheral arterial occlusive disease is described as vascular disorders associated with ischemia and may be the result of an obstructive vascular process or a lost revascularization response. We have shown that gait locomotion analysis by video filming represents an integrative model for the evaluation of mechanisms involved in the process of ischemia-induced revascularization. However, analysis by this method can be subjective and perception errors may be occurring. We present the optimization of a quantifiable, noninvasive, reproducible method that analyzes ankle kinematics in rats using a two-dimensional digital video system. Gait dynamics were filmed in hindlimb ischemic rats with a high speed digital video camera. Images were collected and analyzed at 125 frames per second. An algorithm using interactive data language (IDL) was devised to assess different parameters. In ischemic rats, stride time and knee joint angle remained altered 10 days post-surgery compared with sham animals. Gait kinematics were outlined in a highly reliable way by this computational analysis and corroborated the notion of hindlimb movement recovery associated with the revascularization process.

  13. Friction Stir Welding at MSFC: Kinematics

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.

    2001-01-01

    In 1991 The Welding Institute of the United Kingdom patented the Friction Stir Welding (FSW) process. In FSW a rotating pin-tool is inserted into a weld seam and literally stirs the faying surfaces together as it moves up the seam. By April 2000 the American Welding Society International Welding and Fabricating Exposition featured several exhibits of commercial FSW processes and the 81st Annual Convention devoted a technical session to the process. The FSW process is of interest to Marshall Space Flight Center (MSFC) as a means of avoiding hot-cracking problems presented by the 2195 aluminum-lithium alloy, which is the primary constituent of the Lightweight Space Shuttle External Tank. The process has been under development at MSFC for External Tank applications since the early 1990's. Early development of the FSW process proceeded by cut-and-try empirical methods. A substantial and complex body of data resulted. A theoretical model was wanted to deal with the complexity and reduce the data to concepts serviceable for process diagnostics, optimization, parameter selection, etc. A first step in understanding the FSW process is to determine the kinematics, i.e., the flow field in the metal in the vicinity of the pin-tool. Given the kinematics, the dynamics, i.e., the forces, can be targeted. Given a completed model of the FSW process, attempts at rational design of tools and selection of process parameters can be made.

  14. Spinal astrocytes produce and secrete dynorphin neuropeptides.

    PubMed

    Wahlert, Andrew; Funkelstein, Lydiane; Fitzsimmons, Bethany; Yaksh, Tony; Hook, Vivian

    2013-04-01

    Dynorphin peptide neurotransmitters (neuropeptides) have been implicated in spinal pain processing based on the observations that intrathecal delivery of dynorphin results in proalgesic effects and disruption of extracellular dynorphin activity (by antisera) prevents injury evoked hyperalgesia. However, the cellular source of secreted spinal dynorphin has been unknown. For this reason, this study investigated the expression and secretion of dynorphin-related neuropeptides from spinal astrocytes (rat) in primary culture. Dynorphin A (1-17), dynorphin B, and α-neoendorphin were found to be present in the astrocytes, illustrated by immunofluorescence confocal microscopy, in a discrete punctate pattern of cellular localization. Measurement of astrocyte cellular levels of these dynorphins by radioimmunoassays confirmed the expression of these three dynorphin-related neuropeptides. Notably, BzATP (3'-O-(4-benzoyl)benzoyl adenosine 5'-triphosphate) and KLA (di[3-deoxy-D-manno-octulosonyl]-lipid A) activation of purinergic and toll-like receptors, respectively, resulted in stimulated secretion of dynorphins A and B. However, α-neoendorphin secretion was not affected by BzATP or KLA. These findings suggest that dynorphins A and B undergo regulated secretion from spinal astrocytes. These findings also suggest that spinal astrocytes may provide secreted dynorphins that participate in spinal pain processing.

  15. Perturbed cholesterol homeostasis in aging spinal cord.

    PubMed

    Parkinson, Gemma M; Dayas, Christopher V; Smith, Doug W

    2016-09-01

    The spinal cord is vital for the processing of sensorimotor information and for its propagation to and from both the brain and the periphery. Spinal cord function is affected by aging, however, the mechanisms involved are not well-understood. To characterize molecular mechanisms of spinal cord aging, microarray analyses of gene expression were performed on cervical spinal cords of aging rats. Of the metabolic and signaling pathways affected, cholesterol-associated pathways were the most comprehensively altered, including significant downregulation of cholesterol synthesis-related genes and upregulation of cholesterol transport and metabolism genes. Paradoxically, a significant increase in total cholesterol content was observed-likely associated with cholesterol ester accumulation. To investigate potential mechanisms for the perturbed cholesterol homeostasis, we quantified the expression of myelin and neuroinflammation-associated genes and proteins. Although there was minimal change in myelin-related expression, there was an increase in phagocytic microglial and astrogliosis markers, particularly in the white matter. Together, these results suggest that perturbed cholesterol homeostasis, possibly as a result of increased inflammatory activation in spinal cord white matter, may contribute to impaired spinal cord function with aging.

  16. Perturbed cholesterol homeostasis in aging spinal cord.

    PubMed

    Parkinson, Gemma M; Dayas, Christopher V; Smith, Doug W

    2016-09-01

    The spinal cord is vital for the processing of sensorimotor information and for its propagation to and from both the brain and the periphery. Spinal cord function is affected by aging, however, the mechanisms involved are not well-understood. To characterize molecular mechanisms of spinal cord aging, microarray analyses of gene expression were performed on cervical spinal cords of aging rats. Of the metabolic and signaling pathways affected, cholesterol-associated pathways were the most comprehensively altered, including significant downregulation of cholesterol synthesis-related genes and upregulation of cholesterol transport and metabolism genes. Paradoxically, a significant increase in total cholesterol content was observed-likely associated with cholesterol ester accumulation. To investigate potential mechanisms for the perturbed cholesterol homeostasis, we quantified the expression of myelin and neuroinflammation-associated genes and proteins. Although there was minimal change in myelin-related expression, there was an increase in phagocytic microglial and astrogliosis markers, particularly in the white matter. Together, these results suggest that perturbed cholesterol homeostasis, possibly as a result of increased inflammatory activation in spinal cord white matter, may contribute to impaired spinal cord function with aging. PMID:27459933

  17. Spinal infections in children: A review.

    PubMed

    Tyagi, Rahul

    2016-12-01

    Spinal infections are uncommon but significant causes of morbidity and hospitalization in the paediatric population. These infections encompass a broad range of conditions, from discitis to osteomyelitis and spinal epidural and intramedullary abscesses. Paediatric spinal infections can be caused by a range of bacterial, viral, fungal and parasitic agents. Ultrastructural differences of the vertebrae and associated structures result in distinct mechanisms of pathogenesis of spinal infections in children compared to adults. The non-specific nature of symptoms produced by them can cause considerable diagnostic delays. Magnetic Resonance (MR) imaging can facilitate early identification of the disease, and distinguish it from other spinal pathologies. The association of antimicrobial resistant bacterial strains from some of the cases appears worrisome; as is the increasing incidence of Kingella kingae infections causing spinal infections. Rest and immobilization are the general treatment, and prompt initiation of antimicrobial therapy is warranted to ensure optimal clinical outcome. Most patients generally have a good prognosis; however, early identification and prompt initiation of antimicrobial therapy is essential to achieve the best therapeutic response. PMID:27408498

  18. Symptomatic spinal cord metastasis from cerebral oligodendroglioma.

    PubMed

    Elefante, A; Peca, C; Del Basso De Caro, M L; Russo, C; Formicola, F; Mariniello, G; Brunetti, A; Maiuri, F

    2012-06-01

    Spinal subarachnoid spread is not uncommon in brain oligodendrogliomas; on the other hand, symptomatic involvement of the spinal cord and cauda is very rare, with only 16 reported cases. We report the case of a 41-year-old man who underwent resection of a low-grade frontal oligodendroglioma 4 years previously. He was again observed because of bilateral sciatic pain followed by left leg paresis. A spine MRI showed an intramedullary T12-L1 tumor with root enhancement. At operation, an intramedullary anaplastic oligodendroglioma with left exophytic component was found and partially resected. Two weeks later, a large left frontoparietal anaplastic oligodendroglioma was diagnosed and completely resected. The patient was neurologically stable for 8 months and died 1 year after the spinal surgery because of diffuse brain and spinal leptomeningeal spread. The review of the reported cases shows that spinal symptomatic metastases can occur in both low-grade and anaplastic oligodendrogliomas, even many years after surgery of the primary tumor; however, they exceptionally occur as first clinical manifestation or as anaplastic progression. The spinal seeding represents a negative event leading to a short survival.

  19. Derivation and reliability of kinematic measures of sperm motion.

    PubMed

    Davis, R O; Siemers, R J

    1995-01-01

    Studies of sperm movement are relevant in the diagnosis of sperm function and in investigations of cellular biology. Such studies have been traditionally performed by analysing the kinematics of the flagellum or the head. Analysis of the flagellum can provide insights into the cell biological mechanisms responsible for the control of movement. However, the mathematical correspondence between head kinematics and flagellum kinematics is not unique. Therefore, it is not possible to use head kinematics to obtain detailed insights into cell mechanisms or physiology. The accuracy and precision of kinematic measurements are limited by a number of technical and biological factors. Therefore, the interpretation of kinematic data is dependent on a thorough understanding of the assumptions and conditions underlying the analysis. Evaluation of the reliability of kinematic measurements has suffered because no absolute standard for measurement has existed. The development and application of a new standard based on images which were simulated using the equations of motion is described. Because the kinematics of these images are known prior to empirical measurement, the performance of different methods can be determined absolutely. Some kinematic measures are unreliable because they are inappropriate analogues for engineering concepts. The development and use of appropriate engineering measures for the frequency and amplitude of sperm motion is also described. Some types of sperm motion cannot be analysed using kinematic measures (e.g. hyperactivated movement). The concept of the fractal dimension as a more accurate measurement for such motions is introduced. It is concluded that kinematic measurements of sperm motion can provide valuable information about cell biological mechanisms (in the case of the flagellum) and about general membrane and axoneme function (in the case of the head) when the measurements are made under the appropriate conditions, when standard techniques are

  20. Inducing hindlimb locomotor recovery in adult rat after complete thoracic spinal cord section using repeated treadmill training with perineal stimulation only

    PubMed Central

    Alluin, Olivier; Delivet-Mongrain, Hugo

    2015-01-01

    Although a complete thoracic spinal cord section in various mammals induces paralysis of voluntary movements, the spinal lumbosacral circuitry below the lesion retains its ability to generate hindlimb locomotion. This important capacity may contribute to the overall locomotor recovery after partial spinal cord injury (SCI). In rats, it is usually triggered by pharmacological and/or electrical stimulation of the cord while a robot sustains the animals in an upright posture. In the present study we daily trained a group of adult spinal (T7) rats to walk with the hindlimbs for 10 wk (10 min/day for 5 days/wk), using only perineal stimulation. Kinematic analysis and terminal electromyographic recordings revealed a strong effect of training on the reexpression of hindlimb locomotion. Indeed, trained animals gradually improved their locomotion while untrained animals worsened throughout the post-SCI period. Kinematic parameters such as averaged and instant swing phase velocity, step cycle variability, foot drag duration, off period duration, and relationship between the swing features returned to normal values only in trained animals. The present results clearly demonstrate that treadmill training alone, in a normal horizontal posture, elicited by noninvasive perineal stimulation is sufficient to induce a persistent hindlimb locomotor recovery without the need for more complex strategies. This provides a baseline level that should be clearly surpassed if additional locomotor-enabling procedures are added. Moreover, it has a clinical value since intrinsic spinal reorganization induced by training should contribute to improve locomotor recovery together with afferent feedback and supraspinal modifications in patients with incomplete SCI. PMID:26203108

  1. [Spinal and extra-spinal tumors mimicking discal herniation].

    PubMed

    Tamir, E; Mirovsky, Y; Robinson, D; Halperin, N

    1999-12-15

    Low back pain radiating to a limb is usually caused by lumbar disc herniation. Tumors of the spinal cord or near the sciatic or femoral plexus can cause neural compression and clinical signs similar to those of disc herniation. Such tumors are usually misdiagnosed as discal herniation and appropriate treatment is delayed. We present 4 men who had tumors causing low back pain radiating to the leg: a 70-year-old with metastatic squamous cell carcinoma of the lung, a 20-year-old with aneurysmal bone cyst of the vertebral column, a 52-year-old with retroperitoneal sarcoma and a 32-year-old who also had retroperitoneal sarcoma. Diagnosis and treatment were delayed because the clinical symptoms were ascribed to lumbar disc herniation. The latter 2 patients had CT-scans showing lumbar disc herniation, but similar findings are common among asymptomatic individuals. The differential diagnosis of low back pain radiating to the leg should include tumor when there is a history of cancer, pain not relieved by conservative treatment nor by lying down, pain is increased at night, pain accompanied by weight loss, and when physical examination demonstrates injury to more than 1 nerve root. In these circumstances work-up should include EMG, radioisotope scan and CT of the pelvis.

  2. [Spinal and extra-spinal tumors mimicking discal herniation].

    PubMed

    Tamir, E; Mirovsky, Y; Robinson, D; Halperin, N

    1999-12-15

    Low back pain radiating to a limb is usually caused by lumbar disc herniation. Tumors of the spinal cord or near the sciatic or femoral plexus can cause neural compression and clinical signs similar to those of disc herniation. Such tumors are usually misdiagnosed as discal herniation and appropriate treatment is delayed. We present 4 men who had tumors causing low back pain radiating to the leg: a 70-year-old with metastatic squamous cell carcinoma of the lung, a 20-year-old with aneurysmal bone cyst of the vertebral column, a 52-year-old with retroperitoneal sarcoma and a 32-year-old who also had retroperitoneal sarcoma. Diagnosis and treatment were delayed because the clinical symptoms were ascribed to lumbar disc herniation. The latter 2 patients had CT-scans showing lumbar disc herniation, but similar findings are common among asymptomatic individuals. The differential diagnosis of low back pain radiating to the leg should include tumor when there is a history of cancer, pain not relieved by conservative treatment nor by lying down, pain is increased at night, pain accompanied by weight loss, and when physical examination demonstrates injury to more than 1 nerve root. In these circumstances work-up should include EMG, radioisotope scan and CT of the pelvis. PMID:10959387

  3. Effects of gabapentin on thermal sensitivity following spinal nerve ligation or spinal cord compression.

    PubMed

    Yezierski, Robert P; Green, Megan; Murphy, Karen; Vierck, Charles J

    2013-10-01

    Neuropathic pain challenges healthcare professionals and researchers to develop new strategies of treatment and experimental models to better understand the pathophysiology of this condition. In the present study, the efficacy of gabapentin on thermal sensitivity following spinal nerve ligation and spinal cord compression was evaluated. The method of behavioral assessment was a well-validated cortically dependent operant escape task. Spinal nerve ligation produced peripheral neuropathic pain whereas spinal cord compression, achieved with an expanding polymer placed extradurally, produced a condition of central neuropathic pain. Changes in thermal sensitivity were also observed in animals undergoing nerve ligation surgery without nerve injury. Gabapentin (50 and 100 mg/kg) significantly reduced thermal sensitivity to 10 and 44.5 °C in surgically naive animals as well as those undergoing spinal nerve ligation and spinal cord compression. In conclusion, an operant method of behavioral assessment was used to show that spinal nerve ligation and spinal cord compression produced increases in sensitivity to noxious cold and heat stimuli. A decrease in thermal sensitivity was observed following administration of gabapentin. The results achieved with these methods are consistent with the clinical profile of gabapentin in treating conditions of neuropathic pain.

  4. Assessing small-volume spinal cord dose for repeat spinal stereotactic body radiotherapy treatments

    NASA Astrophysics Data System (ADS)

    Ma, Lijun; Kirby, Neil; Korol, Renee; Larson, David A.; Sahgal, Arjun

    2012-12-01

    Spinal cord biologically effective dose (BED) limits are critical to safe spine stereotactic body radiotherapy (SBRT) delivery. In particular, when repeating SBRT to the same site, the problem of adding non-uniform BED distributions within small volumes of spinal cord has yet to be solved. We report a probability-based generalized BED (gBED) model to guide repeat spine SBRT treatment planning. The gBED was formulated by considering the sequential damaging probabilities of repeat spine SBRT treatments. Parameters from the standard linear-quadratic model, such as α/β = 2 Gy for the spinal cord, were applied. We tested the model based on SBRT specific spinal cord tolerance using a simulated and ten clinical repeat SBRT cases. The gBED provides a consistent solution for superimposing non-uniform dose distributions from different fractionation schemes, analogous to the BED for uniform dose distributions. Based on ten clinical cases, the gBED was observed to eliminate discrepancies in the cumulative BED of approximately 5% to 20% within small volumes (e.g. 0.1-2.0 cc) of spinal cord, as compared to a conventional calculation method. When assessing spinal cord tolerance for repeat spinal SBRT treatments, caution should be exercised when applying conventional BED calculations for small volumes of spinal cord irradiated, and the gBED potentially provides more conservative and consistently derived dose surrogates to guide safe treatment planning and treatment outcome modeling.

  5. Spinal cord infarction: a rare cause of paraplegia

    PubMed Central

    Patel, Sonali; Naidoo, Khimara; Thomas, Peter

    2014-01-01

    Spinal cord infarction is rare and represents a diagnostic challenge for many physicians. There are few reported cases worldwide with a prevalence of 1.2% of all strokes. Circulation to the spinal cord is supplied by a rich anastomosis. The anterior spinal artery supplies the anterior two thirds of the spinal cord and infarction to this area is marked by paralysis, spinothalamic sensory deficit and loss of sphincter control depending on where the lesion is. Treatment of spinal cord infarction focuses on rehabilitation with diverse outcomes. This report presents a case of acute spinal cord infarction with acquisition of MRI to aid diagnosis. PMID:24966260

  6. Spinal cord infarction: a rare cause of paraplegia.

    PubMed

    Patel, Sonali; Naidoo, Khimara; Thomas, Peter

    2014-06-25

    Spinal cord infarction is rare and represents a diagnostic challenge for many physicians. There are few reported cases worldwide with a prevalence of 1.2% of all strokes. Circulation to the spinal cord is supplied by a rich anastomosis. The anterior spinal artery supplies the anterior two thirds of the spinal cord and infarction to this area is marked by paralysis, spinothalamic sensory deficit and loss of sphincter control depending on where the lesion is. Treatment of spinal cord infarction focuses on rehabilitation with diverse outcomes. This report presents a case of acute spinal cord infarction with acquisition of MRI to aid diagnosis.

  7. Clinical Assessment Of Stereotactic IGRT: Spinal Radiosurgery

    SciTech Connect

    Gerszten, Peter C. Burton, Steven A.

    2008-07-01

    The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. Its use for the treatment of spinal lesions has been limited because of the availability of effective target immobilization devices. Recent advances in stereotactic IGRT have allowed for spinal applications. Large clinical experience with spinal radiosurgery to properly assess clinical outcomes has previously been limited. At our institution, we have developed a successful multidisciplinary spinal radiosurgery program in which 542 spinal lesions (486 malignant and 56 benign lesions) were treated with a single-fraction radiosurgery technique. Patient ages ranged from 18 to 85 years (mean 56 years). Lesion location included 92 cervical, 234 thoracic, 130 lumbar, and 86 sacral. The most common metastatic tumors were renal cell (89 cases), breast (74 cases), and lung (71 cases). The most common benign tumors were neurofibroma (24 cases), schwannoma (13 cases), and meningioma (7 cases). Eighty-nine cervical lesions were treated using skull tracking. Thoracic, lumbar, and sacral tumors were tracked relative to either gold or stainless steel fiducial markers. The maximum intratumoral dose ranged from 12.5 to 30 Gy (mean 20 Gy). Tumor volume ranged from 0.16 to 298 mL (mean 47 mL). Three hundred thirty-seven lesions had received prior external beam irradiation with spinal cord doses precluding further conventional irradiation. The primary indication for radiosurgery was pain in 326 cases, as a primary treatment modality in 70 cases, for tumor radiographic tumor progression in 65 cases, for post-surgical treatment in 38 cases, for progressive neurological deficit in 35 cases, and as a radiation boost in 8 cases. Follow-up period was at least 3 to 49 months. Axial and/or radicular pain improved in 300 of 326 cases (92%). Long-term tumor control was demonstrated in 90% of lesions treated with radiosurgery as a primary treatment modality and in 88% of lesions treated for

  8. [Non-invasive transcutaneous spinal cord stimulation facilitates locomotor activity in decerebrated and spinal cats].

    PubMed

    Musienko, P E; Bogacheva, I N; Savochin, A A; Kilimnik, V A; Gorskiĭ, O V; Nikitin, O A; Gerasimenko, Ia P

    2013-08-01

    It is known that spinal neuronal networks activated by epidural electrical stimulation (EES) can produce the stepping EMG pattern and control the locomotor behavior. At present study we showed that non-invasive transcutaneous electrical spinal cord stimulation (tESCS) applied to the lumbar-sacral enlargement can facilitate the locomotor activity in decerebrated and spinal animals. The comparison of the motor responses evoked by EES vs tESCS showed that both methods produce the locomotor patterns with close properties and similar reflex mechanisms. The data obtained suggest that tESCS is an efficient approach for investigation of the locomotor control in acute and chronic experiments as well as facilitates of the locomotor abilities after spinal cord injury. Taking to account the non-invasivity and easement of tESCS, this approach could be further implemented in clinical practice for rehabilitation of the patient with spinal cord injury.

  9. Deployable antenna kinematics using tensegrity structure design

    NASA Astrophysics Data System (ADS)

    Knight, Byron Franklin

    With vast changes in spacecraft development over the last decade, a new, cheaper approach was needed for deployable kinematic systems such as parabolic antenna reflectors. Historically, these mesh-surface reflectors have resembled folded umbrellas, with incremental redesigns utilized to save packaging size. These systems are typically over-constrained designs, the assumption being that high reliability necessary for space operations requires this level of conservatism. But with the rapid commercialization of space, smaller launch platforms and satellite buses have demanded much higher efficiency from all space equipment than can be achieved through this incremental approach. This work applies an approach called tensegrity to deployable antenna development. Kenneth Snelson, a student of R. Buckminster Fuller, invented Tensegrity structures in 1948. Such structures use a minimum number of compression members (struts); stability is maintain using tension members (ties). The novelty introduced in this work is that the ties are elastic, allowing the struts to extend or contract, and in this way changing the surface of the antenna. Previously, the University of Florida developed an approach to quantify the stability and motion of parallel manipulators. This approach was applied to deployable, tensegrity, antenna structures. Based on the kinematic analyses for the 3-3 (octahedron) and 4-4 (square anti-prism) structures, the 6-6 (hexagonal anti-prism) analysis was completed which establishes usable structural parameters. The primary objective for this work was to prove the stability of this class of deployable structures, and their potential application to space structures. The secondary objective is to define special motions for tensegrity antennas, to meet the subsystem design requirements, such as addressing multiple antenna-feed locations. This work combines the historical experiences of the artist (Snelson), the mathematician (Ball), and the space systems engineer

  10. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    ERIC Educational Resources Information Center

    Kranjc, T.; Razpet, N.

    2011-01-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

  11. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    ERIC Educational Resources Information Center

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  12. Zero-Inertial Recession for a Kinematic Wave Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kinematic-wave models of surface irrigation assume a fixed relationship between depth and discharge (typically, normal depth). When surface irrigation inflow is cut off, the calculated upstream flow depth goes to zero, since the discharge is zero. For short time steps, use of the Kinematic Wave mode...

  13. The impact of tibial torsion measurements on gait analysis kinematics

    PubMed Central

    Lucareli, Paulo Roberto Garcia; Santos, Nadia Maria; Godoy, Wagner De; Bernal, Milena Moreira Barreto; Paes, Ângela Tavares; Ramalho, Amancio

    2014-01-01

    Objective: To measure and compare tibial torsion values as assessed by goniometry and three-dimensional kinematics. In addition, the impact of each one of these measurements on kinematic and kinetic results for normal gait was determined. Methods: Twenty-three healthy and fully ambulatory patients were assessed, 11 women and 12 men, from 20 to 40 years old. Data were collected at a laboratory for the three-dimensional analysis of movement with 10 cameras and two force plates. Tibial torsion measurements were obtained using goniometry and three-dimensional kinematics based on the Plug-in Gait model. Afterwards, both procedures were compared, and the impact of each result was assessed on the kinematic and kinetic modeling of the knee and ankle. Results: Pearson's linear correlation coefficient (r=0,504) showed a moderate correlation between the three-dimensional kinematics and goniometry, and between the changes in the measurements. Regarding the processed kinematic and kinetic results for every torsion position, no significant differences were noticed among any of the studied variables (p>0.05). Conclusion: Although statistical correlation among tibial torsion angles by goniometry and three-dimensional kinematic were moderate, kinematic and kinetic analysis of the joints did not reveal any significant changes. Level of Evidence I, Diagnostic Studies - Investigating a Diagnostic Test. PMID:25328438

  14. Kinematic Signatures of Telic and Atelic Events in ASL Predicates

    ERIC Educational Resources Information Center

    Malaia, Evie; Wilbur, Ronnie B.

    2012-01-01

    This article presents an experimental investigation of kinematics of verb sign production in American Sign Language (ASL) using motion capture data. The results confirm that event structure differences in the meaning of the verbs are reflected in the kinematic formation: for example, in the telic verbs (throw, hit), the end-point of the event is…

  15. Dopamine is produced in the rat spinal cord and regulates micturition reflex after spinal cord injury

    PubMed Central

    Hou, Shaoping; Carson, David M.; Wu, Di; Klaw, Michelle C.; Houlé, John D.; Tom, Veronica J.

    2016-01-01

    Dopamine (DA) neurons in the mammalian central nervous system are thought to be restricted to the brain. DA-mediated regulation of urinary activity is considered to occur through an interaction between midbrain DA neurons and the pontine micturition center. Here we show that DA is produced in the rat spinal cord and modulates the bladder reflex. We observed numerous tyrosine hydroxylase (TH)+ neurons in the autonomic nuclei and superficial dorsal horn in L6–S3 spinal segments. These neurons are dopamine-β-hydroxylase (DBH)− and some contain detectable dopamine decarboxylase (DDC), suggesting their capacity to produce DA. Interestingly, following a complete thoracic spinal cord injury (SCI) to interrupt supraspinal projections, more TH+ neurons emerged in the lumbosacral spinal cord, coincident with a sustained, low level of DA expression there and a partially recovered micturition reflex. Non-selective blockade of spinal DA receptors reduced bladder activity whereas activation of spinal D2-like receptors increased bladder activity and facilitated voiding. Additionally, depletion of lumbosacral TH+ neurons with 6-hydroxydopamine (6-OHDA) decreased bladder non-voiding contractions and voiding efficiency. Furthermore, injecting the transsynaptic neuronal tracer pseudorabies virus (PRV) into the bladder detrusor labeled TH+ cells in the lumbosacral cord, confirming their involvement in spinal micturition reflex circuits. These results illustrate that DA is synthesized in the rat spinal cord; plasticity of lumbosacral TH+ neurons following SCI may contribute to DA expression and modulate the spinal bladder reflex. Thus, spinally-derived DA and receptors could be a novel therapeutic target to improve micturition recovery after SCI. PMID:26655672

  16. Characteristics and rehabilitation for patients with spinal cord stab injury.

    PubMed

    Wang, Fangyong; Zhang, Junwei; Tang, Hehu; Li, Xiang; Jiang, Shudong; Lv, Zhen; Liu, Shujia; Chen, Shizheng; Liu, Jiesheng; Hong, Yi

    2015-12-01

    [Purpose] The objective of the study was to compare the incidence, diagnosis, treatment, and prognosis of patients with spinal cord stab injury to those with the more common spinal cord contusion injury. [Subjects] Of patients hospitalized in China Rehabilitation Research Center from 1994 to 2014, 40 of those having a spinal cord stab injury and 50 with spinal cord contusion were selected. [Methods] The data of all patients were analyzed retrospectively. The cases were evaluated by collecting admission and discharge ASIA (American Spinal Injury Association) and ADL (activity of daily living) scores. [Results] After a comprehensive rehabilitation program, ASIA and ADL scores of patients having both spinal cord stab injury and spinal cord contusion significantly increase. However, the increases were noted to be higher in patients having a spinal cord stab injury than those having spinal cord contusion. [Conclusion] Comprehensive rehabilitation is effective both for patients having spinal cord stab injury and those with spinal cord contusion injury. However, the prognosis of patients having spinal cord stab injury is better than that of patients with spinal cord contusion.

  17. Numerical analysis of kinematic soil-pile interaction

    SciTech Connect

    Castelli, Francesco; Maugeri, Michele; Mylonakis, George

    2008-07-08

    In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.

  18. Forward and inverse kinematics of double universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., II

    1991-01-01

    A robot wrist consisting of two universal joints can eliminate the wrist singularity problem found on many individual robots. Forward and inverse position and velocity kinematics are presented for such a wrist having three degrees of freedom. Denavit-Hartenberg parameters are derived to find the transforms required for the kinematic equations. The Omni-Wrist, a commercial double universal joint robot wrist, is studied in detail. There are four levels of kinematic parameters identified for this wrist; three forward and three inverse maps are presented for both position and velocity. These equations relate the hand coordinate frame to the wrist base frame. They are sufficient for control of the wrist standing alone. When the wrist is attached to a manipulator arm; the offset between the two universal joints complicates the solution of the overall kinematics problem. All wrist coordinate frame origins are not coincident, which prevents decoupling of position and orientation for manipulator inverse kinematics.

  19. Relativistic kinematics for motion faster than light

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1982-01-01

    The use of conformal coordinates in relativistic kinematics is illustrated and a simple extension of the theory of motions faster than light is provided. An object traveling at a speed greater than light discloses its presence by appearing suddenly at a point, splitting into two apparent objects which then recede from each other at sublight velocities. According to the present theory motion at speeds faster than light would not benefit a space traveler, since the twin paradox becomes inverted at such speeds. In Einstein's theory travel at the velocity of light in an intertial system is equivalent to infinite velocity for the traveler. In the present theory the converse is also true; travel at infinite velocity is equivalent to the velocity of light for the traveler.

  20. Unraveling L_{n,k}: Grassmannian Kinematics

    SciTech Connect

    Kaplan, Jared; /SLAC

    2010-02-15

    It was recently proposed that the leading singularities of the S-Matrix of N = 4 super Yang-Mills theory arise as the residues of a contour integral over a Grassmannian manifold, with space-time locality encoded through residue theorems generalizing Cauchy's theorem to more than one variable. We provide a method to identify the residue corresponding to any leading singularity, and we carry this out explicitly for all leading singularities at tree level and one-loop. We also give several examples at higher loops, including all generic two-loop leading singularities and an interesting four-loop object. As an example we consider a 12-pt N{sup 4}MHV leading singularity at two loops that has a kinematic structure involving double square roots. Our analysis results in a simple picture for how the topological structure of loop graphs is reflected in various substructures within the Grassmannian.

  1. Galaxy simulations: Kinematics and mock observations

    NASA Astrophysics Data System (ADS)

    Moody, Christopher E.

    2013-08-01

    There are six topics to my thesis, which are: (1) slow rotator production in varied simulation schemes and kinematically decoupled cores and twists in those simulations, (2) the change in number of clumps in radiation pressure and no-radiation pressure simulations, (3) Sunrise experiments and failures including UVJ color-color dust experiments and UVbeta slopes, (4) the Sunrise image pipeline and algorithms. Cosmological simulations of have typically produced too many stars at early times. We find that the additional radiation pressure (RP) feedback suppresses star formation globally by a factor of ~ 3. Despite this reduction, the simulation still overproduces stars by a factor of ~ 2 with respect to the predictions provided by abundance matching methods. In simulations with RP the number of clumps falls dramatically. However, only clumps with masses Mclump/Mdisk ≤ 8% are impacted by the inclusion of RP, and clump counts above this range are comparable. Above this mass, the difference between and RP and no-RP contrast ratios diminishes. If we restrict our selection to galaxies hosting at least a single clump above this mass range then clump numbers, contrast ratios, survival fractions and total clump masses show little discrepancy between RP and no-RP simulations. By creating mock Hubble Space Telescope observations we find that the number of clumps is slightly reduced in simulations with RP. We demonstrate that clumps found in any single gas, stellar, or mock observation image are not necessarily clumps found in another map, and that there are few clumps common to multiple maps. New kinematic observations from ATLAS3D have highlighted the need to understand the evolutionary mechanism leading to a spectrum of fast-rotator and slow-rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamic simulations sampling idealized galaxy merger formation scenarios constructed from model

  2. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, Layton C.

    1997-01-01

    An adjustable link for kinematic mounting systems. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two.

  3. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, L.C.

    1997-07-01

    An adjustable link for kinematic mounting systems is disclosed. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two. 3 figs.

  4. Kinematics of chiropteran shoulder girdle in flight.

    PubMed

    Panyutina, A A; Kuznetsov, A N; Korzun, L P

    2013-03-01

    New data on the mechanisms of movements of the shoulder girdle and humerus of bats are described; potential mobility is compared to the movements actually used in flight. The study was performed on the basis of morphological and functional analysis of anatomical specimens of 15 species, high speed and high definition filming of two species and X-ray survey of Rousettus aegyptiacus flight. Our observations indicate that any excursions of the shoulder girdle in bats have relatively small input in the wing amplitude. Shoulder girdle movements resemble kinematics of a crank mechanism: clavicle plays the role of crank, and scapula-the role of connecting rod. Previously described osseous "locking mechanisms" in shoulder joint of advanced bats do not affect the movements, actually used in flight. The wing beats in bats are performed predominantly by movements of humerus relative to shoulder girdle, although these movements occupy the caudal-most sector of available shoulder mobility. PMID:23381941

  5. Global and regional kinematics from SLR stations

    NASA Technical Reports Server (NTRS)

    Dunn, Peter J.

    1994-01-01

    The stations of the Global Laser Tracking Network have significantly contributed to the measurement of plate kinematics. The expanding network of progressively improved instruments clearly demonstrates the systems' centimeter positioning accuracy. Several satellite laser ranging (SLR) analysis groups have adopted techniques to distill geodynamic information from the Lageos-1 satellite observations using orbital arc lengths from an hour to a decade. SLR observations now provide the scale for the International Terrestrial Reference System and help to define the Earth's polar motion in this system. Agreement between positions separately determined with SLR, VLBI and GPS systems has been established at the level of a few centimeters in position and a few millimeters per year in horizontal velocity.

  6. Differential Kinematics Of Contemporary Industrial Robots

    NASA Astrophysics Data System (ADS)

    Szkodny, T.

    2014-08-01

    The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant's value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

  7. Kinematic Solar Dynamo with Spot Deposition

    NASA Astrophysics Data System (ADS)

    Karak, Bidya Binay; Miesch, Mark S.

    2016-05-01

    We have recently developed a kinematic dynamo model by including the observed differential rotation and the meridional flow. This model includes the emergence of sunspots from the deep-seated toroidal field and their subsequent decay at the surface, i.e., the Babcock-Leighton process for the generation of poloidal field.We shall show that this model reproduces most of the basic features of the solar magnetic cycle including the polarity reversals, 11 years periodicity, equatorward migration of sunspots at low latitudes and the poleward migration of the radial field at the surface. This model also produces the observed cycle variations when the fluctuations in the active-region tilt are included. North-south asymmetries of cycles from this model will also be demonstrated.

  8. Galactic kinematics derived from classical cepheids

    NASA Astrophysics Data System (ADS)

    Zhu, Zi

    On the basis of radial velocity and Hipparcos proper motion data, we have analyzed the galactic kinematics of classical Cepheids. Using the 3-D Ogorodnikov-Milne model we have determined the rotational velocity of the Galaxy to be V0 = 240.5 ± 10.2 km/s, on assuming a glactocentric distance of the Sun of R0 = 8.5 kpc. The results clearly indicate a contracting motion in the solar neighbourhood of (∂V θ∂θ)/R = -2.60 ± 1.07 km s -1 kpc -1, along the direction of galactic rotation. Possible reason for this motion is discussed. The solar motion found here is S⊙ = 18.78 ± 0.86 km/s in the direction l⊙ = 54.4° ± 2.9° and b⊙ = +26.6° ± 2.6°.

  9. Uncertainty quantification in kinematic wave models

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.

    2012-10-01

    We developed a probabilistic approach to quantify parametric uncertainty in first-order hyperbolic conservation laws (kinematic wave equations). The approach relies on the derivation of a deterministic equation for the cumulative density function (CDF) of the system state, in which probabilistic descriptions (probability density functions or PDFs) of the system parameters and/or initial and boundary conditions serve as inputs. In contrast to PDF equations, which are often used in other contexts, CDF equations allow for straightforward and unambiguous determination of boundary conditions with respect to sample variables.The accuracy and robustness of solutions of the CDF equation for one such system, the Saint-Venant equations of river flows, were investigated via comparison with Monte Carlo simulations.

  10. SPACEBAR: Kinematic design by computer graphics

    NASA Technical Reports Server (NTRS)

    Ricci, R. J.

    1975-01-01

    The interactive graphics computer program SPACEBAR, conceived to reduce the time and complexity associated with the development of kinematic mechanisms on the design board, was described. This program allows the direct design and analysis of mechanisms right at the terminal screen. All input variables, including linkage geometry, stiffness, and applied loading conditions, can be fed into or changed at the terminal and may be displayed in three dimensions. All mechanism configurations can be cycled through their range of travel and viewed in their various geometric positions. Output data includes geometric positioning in orthogonal coordinates of each node point in the mechanism, velocity and acceleration of the node points, and internal loads and displacements of the node points and linkages. All analysis calculations take at most a few seconds to complete. Output data can be viewed at the scope and also printed at the discretion of the user.

  11. Adiposity and spinal cord injury

    PubMed Central

    Gorgey, Ashraf S; Wells, Kathryn M; Austin, Timothy L

    2015-01-01

    The drastic changes in body composition following spinal cord injury (SCI) have been shown to play a significant role in cardiovascular and metabolic health. The pattern of storage and distribution of different types of adipose tissue may impact metabolic health variables similar to carbohydrate, lipid and bone metabolism. The use of magnetic resonance imaging provides insights on the interplay among different regional adipose tissue compartments and their role in developing chronic diseases. Regional adipose tissue can be either distributed centrally or peripherally into subcutaneous and ectopic sites. The primary ectopic adipose tissue sites are visceral, intramuscular and bone marrow. Dysfunction in the central nervous system following SCI impacts the pattern of distribution of adiposity especially between tetraplegia and paraplegia. The current editorial is focused primarily on introducing different types of adipose tissue and establishing scientific basis to develop appropriate dietary, rehabilitation or pharmaceutical interventions to manage the negative consequences of increasing adiposity after SCI. We have also summarized the clinical implications and future recommendations relevant to study adiposity after SCI. PMID:26396933

  12. Bone and Spinal Muscular Atrophy.

    PubMed

    Vai, Silvia; Bianchi, Maria Luisa; Moroni, Isabella; Mastella, Chiara; Broggi, Francesca; Morandi, Lucia; Arnoldi, Maria Teresa; Bussolino, Chiara; Baranello, Giovanni

    2015-10-01

    Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disease, leading to progressive denervation atrophy in the involved skeletal muscles. Bone status has been poorly studied. We assessed bone metabolism, bone mineral density (BMD) and fractures in 30 children (age range 15-171 months) affected by SMA types 2 and 3. Eighteen children (60%) had higher than normal levels of CTx (bone resorption marker); 25-OH vitamin D was in the lower range of normal (below 20 ng/ml in 9 children and below 12 ng/ml in 2). Lumbar spine BMAD (bone mineral apparent density) Z-score was below -1.5 in 50% of children. According to clinical records, four children had sustained four peripheral fractures; on spine X-rays, we observed 9 previously undiagnosed vertebral fractures in 7 children. There was a significant inverse regression between PTH and 25-OH D levels, and a significant regression between BMC and BMAD values and the scores of motor-functional tests. Even if this study could not establish the pathogenesis of bone derangements in SMA, its main findings - reduced bone density, low 25OH vitamin D levels, increased bone resorption markers and asymptomatic vertebral fractures also in very young patients - strongly suggest that even young subjects affected by SMA should be considered at risk of osteopenia and even osteoporosis and fractures. PMID:26055105

  13. Color-kinematics duality in multi-Regge kinematics and dimensional reduction

    NASA Astrophysics Data System (ADS)

    Johansson, Henrik; Vera, Agustín Sabio; Campillo, Eduardo Serna; Vázquez-Mozo, Miguel Á.

    2013-10-01

    In this note we study the applicability of the color-kinematics duality to the scattering of two distinguishable scalar matter particles with gluon emission in QCD, or graviton emission in Einstein gravity. Previous analysis suggested that direct use of the Bern-Carrasco-Johansson double-copy prescription to matter amplitudes does not reproduce the gravitational amplitude in multi-Regge kinematics. This situation, however, can be avoided by extensions to the gauge theory, while maintaning the same Regge limit. Here we present two examples of these extensions: the introduction of a scalar contact interaction and the relaxation of the distinguishability of the scalars. In both cases new diagrams allow for a full reconstruction of the correct Regge limit on the gravitational side. Both modifications correspond to theories obtained by dimensional reduction from higher-dimensional gauge theories.

  14. Feeding kinematics of juvenile swellsharks, Cephaloscyllium ventriosum

    PubMed

    Ferry-Graham

    1997-01-01

    To investigate how feeding behaviors change with prey size, high-speed video recording was used to examine the kinematics of prey capture and transport in 1-year-old swellsharks Cephaloscyllium ventriosum (Scyliorhinidae: Carchariniformes) feeding on two differently sized prey items. Prey capture in these sharks generally consisted of an initially ram-dominated capture bite, one or more manipulation bites, a holding phase during which the food was held in the teeth of the shark, and then suction-dominated prey transport. During initial capture and transport, most of the water taken in is forced back out of the mouth anteriorly rather than continuing posteriorly out through the gill openings. Dye experiments in which dye-perfused prey items were ingested by the sharks confirm this observation; distinct jets of colored water were video-taped as they were ejected from the mouth. Very late in prey transport, a bolus of water is ejected through the gill slits; however, by this time, the majority of water appears already to have exited the buccal cavity through the mouth. Such patterns were observed for sharks feeding on both small and large prey items. Although a basic pattern of prey capture and transport was regularly repeated among strikes, kinematic patterns during prey capture and transport were variable both within and among individuals, indicating that prey acquisition is not tightly controlled. However, the amount of variability was similar among prey sizes. In addition, there were no detectable changes in behavior due to prey item size. Ram-suction index values confirmed that similar capture modes were being utilized for both prey sizes. PMID:9319118

  15. Cervical kinematics during drinking in developing chickens.

    PubMed

    Heidweiller, J; Van der Leeuw, A H; Zweers, G A

    1992-05-01

    Development of head neck motion patterns is studied in drinking chickens to examine (1) general motion principles, (2) ontogenetic changes in these patterns, and (3) whether pattern changes are due to scaling effects during growth. Behavioral patterns are analyzed by high speed filming, radiography, and calculation of rotation patterns for each joint during all movement patterns. Flexibility and variability are great, but representative kinematic patterns are selected for immersion, upstroke, and tip-up phases. Five principles were found that control cervical motion. Two principles maximize rotation efficiency: the geometric and lever arm principles. Two trajectory compensating principles occur; one controls compensation for overflexion, and the other corrects curved into straight trajectories of head motion. One principle occurs that minimizes rotation force if large forces tend to develop in one joint. This principle results in a characteristic cervical motion pattern ("bike chain" pattern). There are three developmental periods: (1) hatchlings (2) chickens 1 to 4 weeks old (1-4W), and (3) older than 4 weeks. Each period is characterized by different kinematic patterns. In 1-4W chicks, the rotation force is minimized. In older stages, the cervical joints rotate according to geometric and lever arm principles. The totally different motion pattern in hatchlings results from a different behavioral reaction to water and the influence of large centrifugal forces. Transitions in cervical motion patterns are connected to effects of scaling, primarily changes in head and body weights. Changes in motion patterns are not related to changes in anatomical characters such as flexion extremes and relative length of each vertebra since these are similar in all stages.

  16. A Kinematic Study of Finswimming at Surface

    PubMed Central

    Gautier, Jimmy; Baly, Laurent; Zanone, Pier-Giorgio; Watier, Bruno

    2004-01-01

    Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle) were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01). Mean joint amplitude for the upper limbs (wrist, elbow and shoulder) was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01). This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance. Key Points Finswimmers are at one and the same time a propelling and a propelled body. This study investigates the undulatory motion performed by finswimmers at the surface. Elite male finswimmers were pitching more acutely than female swimmers and showed a smaller knee bending than both novices and elite female swimmers. Finswimmers tended to perform a dolphin-like motion

  17. Feeding kinematics of juvenile swellsharks, Cephaloscyllium ventriosum

    PubMed

    Ferry-Graham

    1997-01-01

    To investigate how feeding behaviors change with prey size, high-speed video recording was used to examine the kinematics of prey capture and transport in 1-year-old swellsharks Cephaloscyllium ventriosum (Scyliorhinidae: Carchariniformes) feeding on two differently sized prey items. Prey capture in these sharks generally consisted of an initially ram-dominated capture bite, one or more manipulation bites, a holding phase during which the food was held in the teeth of the shark, and then suction-dominated prey transport. During initial capture and transport, most of the water taken in is forced back out of the mouth anteriorly rather than continuing posteriorly out through the gill openings. Dye experiments in which dye-perfused prey items were ingested by the sharks confirm this observation; distinct jets of colored water were video-taped as they were ejected from the mouth. Very late in prey transport, a bolus of water is ejected through the gill slits; however, by this time, the majority of water appears already to have exited the buccal cavity through the mouth. Such patterns were observed for sharks feeding on both small and large prey items. Although a basic pattern of prey capture and transport was regularly repeated among strikes, kinematic patterns during prey capture and transport were variable both within and among individuals, indicating that prey acquisition is not tightly controlled. However, the amount of variability was similar among prey sizes. In addition, there were no detectable changes in behavior due to prey item size. Ram-suction index values confirmed that similar capture modes were being utilized for both prey sizes.

  18. Three-Dimensional Kinematic Gait Analysis of Doberman Pinschers with and without Cervical Spondylomyelopathy

    PubMed Central

    Foss, K.; da Costa, R.C.; Moore, S.

    2014-01-01

    Background The optimal treatment of cervical spondylomyelopathy (CSM) is controversial, with the owner’s and clinician’s perception of gait improvement often being used as outcome measures. These methods are subjective and suffer from observer bias. Objectives To establish kinematic gait parameters utilizing digital motion capture in normal Doberman Pinschers and compare them with CSM-affected Dobermans. Animals Nineteen Doberman Pinschers; 10 clinically normal and 9 with CSM. Methods All dogs were enrolled prospectively and fitted with a Lycra® body suit, and motion capture was performed and used to reconstruct a 3-D stick diagram representation of each dog based on 32 reflective markers, from which several parameters were measured. These included stride duration, length, and height; maximal and minimal spinal angles; elbow and stifle flexion and extension; and maximum and minimum distances between the thoracic and pelvic limbs. A random-effects linear regression model was used to compare parameters between groups. Results Significant differences between groups included smaller minimum (mean = 116 mm; P = .024) and maximum (mean = 184 mm; P = .001) distance between the thoracic limbs in CSM-affected dogs. Additionally, thoracic limb stride duration was also smaller (P = .009) in CSM-affected dogs (mean = 0.7 seconds) when compared with normal dogs (mean = 0.8 seconds). In the pelvic limbs, the average stifle flexion (mean = 100°; P = .048) and extension (mean = 136°; P = .009), as well as number of strides (mean = 2.7 strides; P = .033) were different between groups. Conclusions and Clinical Importance Our findings suggest that computerized gait analysis reveals more consistent kinematic differences in the thoracic limbs, which can be used as future objective outcome measures. PMID:23194100

  19. The Photometric and Kinematic Structure of Face-on Disk Galaxies. III. Kinematic Inclinations from Hα Velocity Fields

    NASA Astrophysics Data System (ADS)

    Andersen, David R.; Bershady, Matthew A.

    2013-05-01

    Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained Hα velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i kin = 23° for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20° and 6% at 30°. Kinematic inclinations are consistent with photometric and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical "face-on" Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15° and 5% at 30°. This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness.

  20. Genetics Home Reference: spinal muscular atrophy with progressive myoclonic epilepsy

    MedlinePlus

    ... myoclonic epilepsy spinal muscular atrophy with progressive myoclonic epilepsy Enable Javascript to view the expand/collapse boxes. ... All Description Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) is a neurological condition that causes ...

  1. General Information about Childhood Brain and Spinal Cord Tumors

    MedlinePlus

    ... Cord Tumors Treatment Overview (PDQ®)–Patient Version General Information About Childhood Brain and Spinal Cord Tumors Go ... types of brain and spinal cord tumors. The information from tests and procedures done to detect (find) ...

  2. What Are the Treatments for Spinal Cord Injury (SCI)?

    MedlinePlus

    ... Resources and Publications What are the treatments for spinal cord injury (SCI)? Skip sharing on social media links ... no known ways to reverse damage to the spinal cord. However, researchers are continually working on new treatments, ...

  3. Continuous spinal anaesthesia: what's new and what's not.

    PubMed

    Bevacqua, Brian K

    2003-09-01

    Continuous spinal anaesthesia combines the advantages of single-dose spinal anaesthesia, rapid onset and a high degree of success, with those of a continuous technique. The introduction of micro-catheters invigorated interest in the technique and allowed its expansion to additional populations and surgical procedures. However, multiple cases of cauda equina syndrome associated with micro-catheters and (primarily) hyperbaric lidocaine solution led to withdrawal of micro-catheters from the US market, casting doubt over the safety of continuous spinal anaesthesia as a whole. A decade after these events it is possible to look back at the experience with continuous spinal anaesthesia for operative anaesthesia and postoperative analgesia and to compare it with the available alternatives. From this perspective, continuous spinal anaesthesia remains a useful and safe technique. Future research should focus on the comparison of continuous spinal anaesthesia with the combined spinal/epidural technique and the use of newer spinal agents.

  4. Vocational Rehabilitation of Persons with Spinal Cord Injuries

    ERIC Educational Resources Information Center

    Poor, Charles R.

    1975-01-01

    Reviews historical development of organized vocational rehabilitation programming for the spinal cord injured in the United States. Significant factors that affect vocational rehabilitation outcomes with spinal cord injured persons are listed and discussed. (Author)

  5. Radiation tolerance of the cervical spinal cord

    SciTech Connect

    McCunniff, A.J.; Liang, M.J.

    1989-03-01

    The incidence of permanent injury to the spinal cord as a complication of radiation therapy generally correlates positively with total radiation dosage. However, several reports in the literature have indicated that fraction size is also an important factor in the development or nondevelopment of late injuries in normal tissue. To determine the effect of fraction size on the incidence of radiation-induced spinal cord injuries, we reviewed 144 cases of head and neck cancer treated at our institution between 1971 and 1980 with radiation greater than 5600 cGy to a portion of the cervical spinal cord. Most of these patients received greater than or equal to 6000 cGy, with fraction sizes ranging from 133 cGy to 200 cGy. Fifty-three of the 144 patients have been followed up for 2 years or more. Nearly half of these (26 patients) received greater than 6000 cGy with fraction sizes of 133 cGy to 180 cGy. Only 1 of the 53 (1.9%) has sustained permanent spinal cord injury; 20 months after completion of radiation treatments he developed Brown-Sequard syndrome. Our experience suggests that radiation injuries to the spinal cord correlate not only with total radiation dosage, but also with fraction size; low fraction sizes appear to decrease the incidence of such injuries.

  6. Regression Segmentation for M³ Spinal Images.

    PubMed

    Wang, Zhijie; Zhen, Xiantong; Tay, KengYeow; Osman, Said; Romano, Walter; Li, Shuo

    2015-08-01

    Clinical routine often requires to analyze spinal images of multiple anatomic structures in multiple anatomic planes from multiple imaging modalities (M(3)). Unfortunately, existing methods for segmenting spinal images are still limited to one specific structure, in one specific plane or from one specific modality (S(3)). In this paper, we propose a novel approach, Regression Segmentation, that is for the first time able to segment M(3) spinal images in one single unified framework. This approach formulates the segmentation task innovatively as a boundary regression problem: modeling a highly nonlinear mapping function from substantially diverse M(3) images directly to desired object boundaries. Leveraging the advancement of sparse kernel machines, regression segmentation is fulfilled by a multi-dimensional support vector regressor (MSVR) which operates in an implicit, high dimensional feature space where M(3) diversity and specificity can be systematically categorized, extracted, and handled. The proposed regression segmentation approach was thoroughly tested on images from 113 clinical subjects including both disc and vertebral structures, in both sagittal and axial planes, and from both MRI and CT modalities. The overall result reaches a high dice similarity index (DSI) 0.912 and a low boundary distance (BD) 0.928 mm. With our unified and expendable framework, an efficient clinical tool for M(3) spinal image segmentation can be easily achieved, and will substantially benefit the diagnosis and treatment of spinal diseases.

  7. Imaging features of spinal tanycytic ependymoma.

    PubMed

    Tomek, Michal; Jayajothi, Anandapadmanabhan; Brandner, Sebastian; Jaunmuktane, Zane; Lee, Cheong Hung; Davagnanam, Indran

    2016-02-01

    Tanycytic ependymoma is an unusual morphological variant of WHO grade II ependymoma, typically arising from the cervical or thoracic spinal cord. Although the literature deals extensively with pathological features of this tumour entity, imaging features have not been well characterised. The purpose of this study was to review magnetic resonance imaging (MRI) features of spinal tanycytic ependymomas reported in the literature to date, exemplified by a case of a patient with tanycytic ependymoma of the conus medullaris presenting to our hospital. A Medline search of the English literature for all previously published cases of spinal tanycytic ependymoma was carried out and the reported MRI features reviewed. The tumours were found to be typically well-demarcated masses, predominantly showing isointensity on T1-weighted signal, and T2-weighted hyperintensity, with variable patterns of contrast enhancement. A cystic component was seen in half of the cases, and in a minority a mural nodule was present within the cyst wall. Associated syrinx formation was observed in one-third of the cases and haemorrhage was rare, which may be helpful pointers in differentiating the lesion from other ependymoma subtypes. In conclusion, MRI characteristics of spinal tanycytic ependymoma are variable and non-specific, and radiological diagnosis thus remains challenging, although certain predominant features are identified in this report. Knowledge of these is important in the diagnostic differentiation from other intramedullary and extramedullary spinal tumours in order to guide appropriate surgical management. PMID:26755489

  8. Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    NASA Astrophysics Data System (ADS)

    García-Lorenzo, B.; Márquez, I.; Barrera-Ballesteros, J. K.; Masegosa, J.; Husemann, B.; Falcón-Barroso, J.; Lyubenova, M.; Sánchez, S. F.; Walcher, J.; Mast, D.; García-Benito, R.; Méndez-Abreu, J.; van de Ven, G.; Spekkens, K.; Holmes, L.; Monreal-Ibero, A.; del Olmo, A.; Ziegler, B.; Bland-Hawthorn, J.; Sánchez-Blázquez, P.; Iglesias-Páramo, J.; Aguerri, J. A. L.; Papaderos, P.; Gomes, J. M.; Marino, R. A.; González Delgado, R. M.; Cortijo-Ferrero, C.; López-Sánchez, A. R.; Bekeraitė, S.; Wisotzki, L.; Bomans, D.

    2015-01-01

    Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims: The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods: After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726,3729, [O iii] λλ4959,5007, Hα+[N ii] λλ6548,6584, and [SII]λλ6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [O iii] λλ4959,5007 emission line profiles. Results: At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear

  9. Paraplegia due to Spinal Epidermoid Cyst Rupture at Asthma Attack

    PubMed Central

    Kim, Kweon Young; Kang, Jung Hun; Choi, Dae Woo; Lee, Min Hong

    2013-01-01

    Spinal epidermoid cyst is less than 1% of the entire spinal cord tumor and a rare tumor. It is a slowly proliferating benign tumor and can be a result of either congenital or acquired factors. In particular, reports of acute paraplegia due to spinal epidermoid cyst rupture are very rare. Since authors experienced paraplegia resulting from congenital spinal epidermoid cyst rupture during an asthma attack, it is reported with a review of literature. PMID:23705125

  10. [Spinal sonography of a newborn infant with postpartal paraplegia].

    PubMed

    Sauter, R; Klemm, T

    1988-01-01

    Cranial ultrasonography is a well established diagnostic procedure. In contrast ultrasonography of the spine and the spinal cord is less frequently used. It is indicated in infants with spinal dysraphism and may help to diagnose patients with meningomyelocele, spinal lipoma or cord tethering. We present a newborn with parplectic symptoms as a result of an epidural hematoma, which could be demonstrated exclusively by ultrasonography. We want to stress that spinal ultrasonography is a method of high clinical value.

  11. MRI Evaluation of Spinal Length and Vertebral Body Angle During Loading with a Spinal Compression Harness

    NASA Technical Reports Server (NTRS)

    Campbell, James A.; Hargens, Alan R.; Murthy, G.; Ballard, R. E.; Watenpaugh, D. E.; Hargens, Alan, R.; Sanchez, E.; Yang, C.; Mitsui, I.; Schwandt, D.; Fechner, K. P.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Weight bearing by the spinal column during upright posture often plays a role in the common problem of low back pain. Therefore, we developed a non-ferromagnetic spinal compression harness to enable MRI investigations of the spinal column during axial loading. Human subjects were fitted with a Nest and a footplate which were connected by adjustable straps to an analog load cell. MRI scans of human subjects (5 males and 1 female with age range of 27-53 yrs) during loaded and unloaded conditions were accomplished with a 1.5 Tesla GE Signa scanner. Studies of two subjects undergoing sequentially increasing spinal loads revealed significant decreases (r(sup 2) = 0.852) in spinal length between T4 and L5 culminating in a 1.5 to 2% length decrease during loading with 75% body weight. Sagittal vertebral body angles of four subjects placed under a constant 50% body weight load for one hour demonstrated increased lordotic and kyphotic curvatures. In the lumbar spine, the L2 vertebral body experienced the greatest angular change (-3 deg. to -5 deg.) in most subjects while in the thoracic spine, T4 angles increased from the unloaded state by +2 deg. to +9 deg. Overall, our studies demonstrate: 1) a progressive, although surprisingly small, decrease in spinal length with increasing load and 2) relatively large changes in spinal column angulation with 50% body weight.

  12. Spinal Cord Tolerance in the Age of Spinal Radiosurgery: Lessons From Preclinical Studies

    SciTech Connect

    Medin, Paul M.; Boike, Thomas P.

    2011-04-01

    Clinical implementation of spinal radiosurgery has increased rapidly in recent years, but little is known regarding human spinal cord tolerance to single-fraction irradiation. In contrast, preclinical studies in single-fraction spinal cord tolerance have been ongoing since the 1970s. The influences of field length, dose rate, inhomogeneous dose distributions, and reirradiation have all been investigated. This review summarizes literature regarding single-fraction spinal cord tolerance in preclinical models with an emphasis on practical clinical significance. The outcomes of studies that incorporate uniform irradiation are surprisingly consistent among multiple small- and large-animal models. Extensive investigation of inhomogeneous dose distributions in the rat has demonstrated a significant dose-volume effect while preliminary results from one pig study are contradictory. Preclinical spinal cord dose-volume studies indicate that dose distribution is more critical than the volume irradiated suggesting that neither dose-volume histogram analysis nor absolute volume constraints are effective in predicting complications. Reirradiation data are sparse, but results from guinea pig, rat, and pig studies are consistent with the hypothesis that the spinal cord possesses a large capacity for repair. The mechanisms behind the phenomena observed in spinal cord studies are not readily explained and the ability of dose response models to predict outcomes is variable underscoring the need for further investigation. Animal studies provide insight into the phenomena and mechanisms of radiosensitivity but the true significance of animal studies can only be discovered through clinical trials.

  13. Measuring spinal canal size in lumbar spinal stenosis: description of method and preliminary results

    PubMed Central

    Makirov, Serik K.; Osadchiy, Valentin

    2015-01-01

    Background Lumbar spinal stenosis is a pathological condition of the spinal channel with its concentric narrowing with presence of specific clinical syndrome. Absence of the clear unified radiological signs is the one of the basic problems of the lumbar spinal stenosis. Purpose The authors seek to create method of assessment of the spinal canal narrowing degree, based on anatomical aspects of lumbar spinal stenosis. Study Design Development of diagnostic criteria based on analysis of a consecutive patients group and a control group. Methods Thirty seven patients (73 stenotic segments) with mean age 62,4 years old were involved in the study. Severity of clinical symptoms has been estimated by the measuring scales: Oswestry Disability Index (ODI) and Swiss Spinal Stenosis Questionnaire (SSQ). Mean number of the stenotic segments was 1.97. For all patients 8 radiological criteria have been measured. In the control group have been included 37 randomly selected patients (volunteers) in mean age of 53,4 years old without stenosis signs and narrowing of the spinal canal on the MRI imaging (73 segments total). Measurements were performed at the middle of intervertebral disc and facet joints level. Results For description of the state of spinal canal we offer the coefficient: ratio of the lateral canals total area to the cross-sectional area of the dural sac (“coefficient of stenosis”). Comparison of mean values of “coefficient of stenosis” for main and control groups showed statistically significant differences (t = -12,5; p < 0.0001). Strong statistically significant correlation with the ODI and SSS scales was revealed for the obtained coefficient (p <0.05). Conclusions In our study new method of assessment of the spinal canal narrowing degree has been applied. Promising results have been obtained in a small group of patients. It is necessary to check the data on a large sample of recommendations for its clinical application. PMID:25834777

  14. Causes of Spinal Cord Injury

    PubMed Central

    2013-01-01

    Background: Knowledge of the causes of spinal cord injury (SCI) and associated factors is critical in the development of successful prevention programs. Objective: This study analyzed data from the National SCI Database (NSCID) and National Shriners SCI Database (NSSCID) in the United States to examine specific etiologies of SCI by age, sex, race, ethnicity, day and month of injury, and neurologic outcomes. Methods: NSCID and NSSCID participants who had a traumatic SCI from 2005 to 2011 with known etiology were included in the analyses (N=7,834). Thirty-seven causes of injury documented in the databases were stratified by personal characteristics using descriptive analysis. Results: The most common causes of SCI were automobile crashes (31.5%) and falls (25.3%), followed by gunshot wounds (10.4%), motorcycle crashes (6.8%), diving incidents (4.7%), and medical/surgical complications (4.3%), which collectively accounted for 83.1% of total SCIs since 2005. Automobile crashes were the leading cause of SCI until age 45 years, whereas falls were the leading cause after age 45 years. Gunshot wounds, motorcycle crashes, and diving caused more SCIs in males than females. The major difference among race/ethnicity was in the proportion of gunshot wounds. More SCIs occurred during the weekends and warmer months, which seemed to parallel the increase of motorcycle- and diving-related SCIs. Level and completeness of injury are also associated with etiology of injury. Conclusions: The present findings suggest that prevention strategies should be tailored to the targeted population and major causes to have a meaningful impact on reducing the incidence of SCI. PMID:23678280

  15. The use of dual growing rods to correct spinal deformity secondary to a low-grade spinal cord astrocytoma

    PubMed Central

    Kuhn, Elizabeth N.; Muthigi, Akhil; Frino, John; Powers, Alexander K.

    2015-01-01

    Pediatric intramedullary spinal cord astrocytomas are rare, and the majority are low grade, typically carrying a low risk of mortality, but a high risk of morbidity. Quality of life is, therefore, an important consideration in treating concomitant progressive kyphoscoliosis. Compared with fusion-based spinal stabilization, fusionless techniques may limit some complications related to early instrumentation of the developing spine. Another consideration is the timing of radiation therapy relative to both spinal maturity and spinal instrumentation. To date, there have been no reports of the use of a fusionless technique to treat spinal deformity secondary to an intramedullary spinal cord tumor. Herein, we report the use of fusionless spinal stabilization with dual growing rods in a boy with low-grade spinal cord astrocytoma after radiation therapy. PMID:26468485

  16. Turkish Adaptation of Spinal Cord Independence Measure--Version III

    ERIC Educational Resources Information Center

    Kesiktas, Nur; Paker, Nurdan; Bugdayci, Derya; Sencan, Sureyya; Karan, Ayse; Muslumanoglu, Lutfiye

    2012-01-01

    Various rating scales have been used to assess ability in individuals with spinal cord injury. There is no specific functional assessment scale for Turkish patients with spinal cord injury. The Spinal Cord Independence Measure (SCIM) is a specific test, which has become popular in the last decade. A study was conducted to validate and evaluate the…

  17. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... measured by reading the height of the fluid. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device...

  18. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... measured by reading the height of the fluid. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device...

  19. Sexuality Counseling with Clients Who Have Spinal Cord Injuries.

    ERIC Educational Resources Information Center

    Farrow, Jeff

    1990-01-01

    Examines effects of spinal cord injury on sexuality. Discusses areas of sexual concern. Provides suggestions for treating clients with spinal cord injuries experiencing sexual difficulties. Concludes that major goal in working with clients with spinal cord injuries who have sexual difficulties should be the facilitation of a creative and…

  20. Spinal chondromyxoid fibroma of C2.

    PubMed

    Bala, Arul; Robbins, Peter; Knuckey, Neville; Wong, George; Lee, Gabriel

    2006-01-01

    Chondromyxoid fibroma of bone (CMF) is a rare benign primary bone neoplasm accounting for less than 0.5% of all primary bone neoplasms. The spine is an uncommon site for this tumour, with forty-two cases reported in the modern English literature. They have clinical features similar to CMF arising at other sites. Local recurrence is well documented. We report an incidentally discovered lytic lesion of the C2 vertebra. The patient underwent stereotactic CT guided trans-oral curettage of the lesion with iliac bone graft and anterior fusion of C2 and C3. Microscopic examination of the surgical specimen demonstrated CMF. This is the second reported case of this rare tumour in this location. We review the literature and the unique radiological and pathological features and management of spinal CMF. Local recurrence of spinal CMF and its management is also discussed in light of the five previously reported cases of local spinal recurrence. PMID:16410218

  1. Primary Multifocal Gliosarcoma of the Spinal Cord

    PubMed Central

    Kumar, Ramesh M.; Finn, Michael

    2016-01-01

    Gliosarcoma (GS) is a rare and exceedingly malignant neoplasm of the central nervous system. It displays clinical features similar to glioblastoma, yet is histologically unique as it harbors both gliomatous and sarcomatous cellular components. Involvement of the neuro-axis is predominantly limited to the cerebral parenchyma and meninges. Primary GS of the spinal cord is rarely encountered. We report a case of a 54 year old male who presented with 2 months of progressive, bilateral lower extremity sensory deficits. Magnetic resonance imaging of the neuro-axis revealed multiple intradural lesions involving the cervical and thoracic spinal cord without evidence of intracranial involvement. Surgical resection of a dural based, extramedullary cervical lesion and two exophytic, intramedullary thoracic lesions revealed gliosarcoma, WHO grade IV. The patient died approximately 11 months after presentation. This report confirms that GS is not limited to supratentorial involvement and can primarily affect the spinal cord. PMID:27134708

  2. Intractable Pruritus After Traumatic Spinal Cord Injury

    PubMed Central

    Crane, Deborah A; Jaffee, Kenneth M; Kundu, Anjana

    2009-01-01

    Background: This report describes a young woman with incomplete traumatic cervical spinal cord injury and intractable pruritus involving her dorsal forearm. Method: Case report. Findings: Anatomic distribution of the pruritus corresponded to the dermatomal distribution of her level of spinal cord injury and vertebral fusion. Symptoms were attributed to the spinal cord injury and possible cervical root injury. Pruritus was refractory to all treatments, including topical lidocaine, gabapentin, transcutaneous electrical nerve stimulation, intravenous Bier block, stellate ganglion block, and acupuncture. Conclusions: Further understanding of neuropathic pruritus is needed. Diagnostic workup of intractable pruritus should include advanced imaging to detect ongoing nerve root compression. If diagnostic studies suggest radiculopathy, epidural steroid injection should be considered. Because the autonomic nervous system may be involved in complex chronic pain or pruritic syndromes, sympatholysis via such techniques as stellate ganglion block might be effective. PMID:19777867

  3. Applier tool for intradural spinal cord implants.

    PubMed

    Oya, H; Reddy, C G; Dahdaleh, N S; Wilson, S; Howard, M A; Jeffery, N D; Utz, M; Gillies, G T

    2012-04-01

    We have designed, built and tested a novel device for placing intradural neurmodulator implants directly on the pial surface of the spinal cord. This applier tool is designed for ergonomic handling of delicate electro-mechanical devices such as the Iowa-Patch™ spinal cord stimulator implant, which is aimed at overcoming certain shortcomings in the performance of standard epidural stimulator devices. The applier is approximately 14 cm long, 6 mm in diameter, made of stainless steel components, and has simple and reliable mechanisms for the attachment and release of the implant from it. We describe the design of the device, details of its construction, and its performance during in vivo testing of somatosensory evoked potentials in an ovine model of intradural spinal cord stimulation. PMID:22339111

  4. Percutaneous endoscopic decompression for lumbar spinal stenosis.

    PubMed

    Ahn, Yong

    2014-11-01

    Percutaneous endoscopic lumbar discectomy has become a representative minimally invasive spine surgery for lumbar disc herniation. Due to the remarkable evolution in the techniques available, the paradigm of spinal endoscopy is shifting from treatments of soft disc herniation to those of lumbar spinal stenosis. Lumbar spinal stenosis can be classified into three categories according to pathological zone as follows: central stenosis, lateral recess stenosis and foraminal stenosis. Moreover, percutaneous endoscopic decompression (PED) techniques may vary according to the type of lumbar stenosis, including interlaminar PED, transforaminal PED and endoscopic lumbar foraminotomy. However, these techniques are continuously evolving. In the near future, PED for lumbar stenosis may be an efficient alternative to conventional open lumbar decompression surgery.

  5. Coordination of spinal locomotor activity in the lamprey: long-distance coupling of spinal oscillators.

    PubMed

    McClellan, A D; Hagevik, A

    1999-05-01

    The extent and strength of long-distance coupling between locomotor networks in the rostral and caudal spinal cord of larval lamprey were examined with in vitro brain/spinal cord preparations, in which spinal locomotor activity was initiated by chemical microstimulation in the brain, as well as with computer modeling. When locomotor activity and short-distance coupling were blocked in the middle spinal cord for at least 40 segments, burst activity in the rostral and caudal spinal cord was still coupled 1:1, indicating that long-distance coupling is extensive. However, in the absence of short-distance coupling, intersegmental phase lags were not constant but decreased significantly with increasing cycle times, suggesting that long-distance coupling maintains a relatively constant delay rather than a constant phase lag between rostral and caudal bursts. In addition, under these conditions, intersegmental phase lags, measured between rostral and caudal burst activity, were significantly less than normal, and the decrease was greater for longer distances between rostral and caudal locomotor networks. The above result could be mimicked by a computer model consisting of pairs of oscillators in the rostral, middle, and caudal spinal cord that were connected by short- and long-distance coupling. With short-distance coupling blocked in the middle spinal cord, strychnine was applied to either the rostral or caudal spinal cord to convert the pattern locally from right-left alternation to synchronous burst activity. Synchronous burst activity in the rostral spinal cord resulted in a reduction in right-left phase values for burst activity in the caudal cord. These results also could be mimicked by the computer model. Strychnine-induced synchronous burst activity in the caudal spinal cord did not appear to alter the right-left phase values of rostral burst activity. Taken together, the experimental and modeling results suggest that the descending and ascending components of long

  6. Organisation of the spinal central pattern generators for locomotion in the salamander: biology and modelling.

    PubMed

    Chevallier, Stéphanie; Jan Ijspeert, Auke; Ryczko, Dimitri; Nagy, Frédéric; Cabelguen, Jean-Marie

    2008-01-01

    Among living tetrapods, salamanders are regarded as most closely resembling the first terrestrial vertebrates, and are therefore an interesting group in which the evolutionary changes in the locomotor behaviour from aquatic to terrestrial habitats can be inferred. Salamanders exhibit two locomotor modes: swimming and terrestrial stepping. The swimming is anguilliform and resembles closely that of the lamprey. On the ground, the salamander switches to a stepping gait with axial undulations that is also observed in many reptiles. The salamander is therefore ideally suited for examining the neural mechanisms for the generation of these two locomotor modes, as well as the neural mechanisms of gait transition. In the present paper, we describe the kinematics and patterns of activation of axial and limb muscles during stepping and swimming in adult salamanders. We then review the current neurobiological data about the organisation of the spinal networks underlying swimming and stepping, and the mechanisms of gait transition. Finally we report modelling studies aimed at understanding the organisation and operation of the salamander locomotor circuits. Altogether, the neurobiological and the modelling data support the hypothesis of a phylogenetic conservatism from agnathians to amphibians of the spinal locomotor networks generating axial motor patterns.

  7. Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats

    PubMed Central

    de la Torre Valdovinos, Braniff; Duenas Jimenez, Judith Marcela; Estrada, Ismael Jimenez; Banuelos Pineda, Jacinto; Franco Rodriguez, Nancy Elizabeth; Lopez Ruiz, Jose Roberto; Osuna Carrasco, Laura Paulina; Candanedo Arellano, Ahiezer; Duenas Jimenez, Sergio Horacio

    2016-01-01

    We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI), in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD) of the pendulum-like movements (PLM) during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats. PMID:27006979

  8. Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats.

    PubMed

    de la Torre Valdovinos, Braniff; Duenas Jimenez, Judith Marcela; Estrada, Ismael Jimenez; Banuelos Pineda, Jacinto; Franco Rodriguez, Nancy Elizabeth; Lopez Ruiz, Jose Roberto; Osuna Carrasco, Laura Paulina; Candanedo Arellano, Ahiezer; Duenas Jimenez, Sergio Horacio

    2016-01-01

    We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI), in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD) of the pendulum-like movements (PLM) during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats. PMID:27006979

  9. Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion

    PubMed Central

    Jung, R; Belanger, A; Kanchiku, T; Fairchild, M; Abbas, J J

    2016-01-01

    The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 ± 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI. PMID:19721184

  10. Evaluation of Diagnosis Techniques Used for Spinal Injury Related Back Pain

    PubMed Central

    Janssen, Meaghan; Nabih, Aliaa; Moussa, Walied; Kawchuk, Gregory N.; Carey, Jason P.

    2011-01-01

    Back pain is a prevalent condition affecting much of the population at one time or the other. Complications, including neurological ones, can result from missed or mismanaged spinal abnormalities. These complications often result in serious patient injury and require more medical treatment. Correct diagnosis enables more effective, often less costly treatment methods. Current diagnosis technologies focus on spinal alterations. Only approximately 10% of back pain is diagnosable, with current diagnostic technologies. The objective of this paper is to investigate and evaluate based on specific criteria current diagnosis technique. Nine diagnostic techniques were found in the literature, namely, discography, myelography, single photon emission computer tomography (SPECT), computer tomography (CT), combined CT & SPECT, magnetic resonance imaging (MRI), upright and kinematic MRI, plain radiography and cineradiography. Upon review of the techniques, it is suggested that improvements can be made to all the existing techniques for diagnosing back pain. This review will aid health service developers to focus on insufficient areas, which will help to improve existing technologies or even develop alternative ones. PMID:22110925

  11. Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion

    NASA Astrophysics Data System (ADS)

    Jung, R.; Belanger, A.; Kanchiku, T.; Fairchild, M.; Abbas, J. J.

    2009-10-01

    The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 ± 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI.

  12. Metal levels in corrosion of spinal implants

    PubMed Central

    Beguiristain, Jose; Duart, Julio

    2007-01-01

    Corrosion affects spinal instrumentations and may cause local and systemic complications. Diagnosis of corrosion is difficult, and nowadays it is performed almost exclusively by the examination of retrieved instrumentations. We conducted this study to determine whether it is possible to detect corrosion by measuring metal levels on patients with posterior instrumented spinal fusion. Eleven asymptomatic patients, with radiological signs of corrosion of their stainless steel spinal instrumentations, were studied by performing determinations of nickel and chromium in serum and urine. Those levels were compared with the levels of 22 patients with the same kind of instrumentation but without evidence of corrosion and to a control group of 22 volunteers without any metallic implants. Statistical analysis of our results revealed that the patients with spinal implants without radiological signs of corrosion have increased levels of chromium in serum and urine (P < 0.001) compared to volunteers without implants. Corrosion significantly raised metal levels, including nickel and chromium in serum and urine when compared to patients with no radiological signs of corrosion and to volunteers without metallic implants (P < 0.001). Metal levels measured in serum have high sensibility and specificity (area under the ROC curve of 0.981). By combining the levels of nickel and chromium in serum we were able to identify all the cases of corrosion in our series of patients. The results of our study confirm that metal levels in serum and urine are useful in the diagnosis of corrosion of spinal implants and may be helpful in defining the role of corrosion in recently described clinical entities such as late operative site pain or late infection of spinal implants. PMID:17256156

  13. Gait kinematic analysis in patients with a mild form of central cord syndrome

    PubMed Central

    2011-01-01

    Background Central cord syndrome (CCS) is considered the most common incomplete spinal cord injury (SCI). Independent ambulation was achieved in 87-97% in young patients with CCS but no gait analysis studies have been reported before in such pathology. The aim of this study was to analyze the gait characteristics of subjects with CCS and to compare the findings with a healthy age, sex and anthropomorphically matched control group (CG), walking both at a self-selected speed and at the same speed. Methods Twelve CCS patients and a CG of twenty subjects were analyzed. Kinematic data were obtained using a three-dimensional motion analysis system with two scanner units. The CG were asked to walk at two different speeds, at a self-selected speed and at a slower one, similar to the mean gait speed previously registered in the CCS patient group. Temporal, spatial variables and kinematic variables (maximum and minimum lower limb joint angles throughout the gait cycle in each plane, along with the gait cycle instants of occurrence and the joint range of motion - ROM) were compared between the two groups walking at similar speeds. Results The kinematic parameters were compared when both groups walked at a similar speed, given that there was a significant difference in the self-selected speeds (p < 0.05). Hip abduction and knee flexion at initial contact, as well as minimal knee flexion at stance, were larger in the CCS group (p < 0.05). However, the range of knee and ankle motion in the sagittal plane was greater in the CG group (p < 0.05). The maximal ankle plantar-flexion values in stance phase and at toe off were larger in the CG (p < 0.05). Conclusions The gait pattern of CCS patients showed a decrease of knee and ankle sagittal ROM during level walking and an increase in hip abduction to increase base of support. The findings of this study help to improve the understanding how CCS affects gait changes in the lower limbs. PMID:21288347

  14. Neuromodulation of the lumbar spinal locomotor circuit.

    PubMed

    AuYong, Nicholas; Lu, Daniel C

    2014-01-01

    The lumbar spinal cord contains the necessary circuitry to independently drive locomotor behaviors. This function is retained following spinal cord injury (SCI) and is amenable to rehabilitation. Although the effectiveness of task-specific training and pharmacologic modulation has been repeatedly demonstrated in animal studies, results from human studies are less striking. Recently, lumbar epidural stimulation (EDS) along with locomotor training was shown to restore weight-bearing function and lower-extremity voluntary control in a chronic, motor-complete human SCI subject. Related animal studies incorporating EDS as part of the therapeutic regiment are also encouraging. EDS is emerging as a promising neuromodulatory tool for SCI. PMID:24262896

  15. Magnetic Resonance Imaging of Spinal Emergencies.

    PubMed

    Kawakyu-O'Connor, Daniel; Bordia, Ritu; Nicola, Refky

    2016-05-01

    Magnetic resonance (MR) imaging of the spine is increasingly being used in the evaluation of spinal emergencies because it is highly sensitive and specific in the diagnosis of acute conditions of the spine. The prompt and accurate recognition allows for appropriate medical and surgical intervention. This article reviews the MR imaging features of common emergent conditions, such as spinal trauma, acute disc herniation, infection, and tumors. In addition, we describe common MR imaging sequences, discuss challenges encountered in emergency imaging of the spine, and illustrate multiple mimics of acute conditions. PMID:27150322

  16. Tadpole system as new lumbar spinal instrumentation

    PubMed Central

    Kasai, Yuichi; Inaba, Tadashi; Akeda, Koji; Uchida, Atsumasa

    2008-01-01

    Background There have been reports of serious complications associated with pedicle screw fixation, including nerve root injuries caused by accidental screw insertion. We have developed a new system of lumbar spinal instrumentation that we call Tadpole system®. The purposes of this report were to show the results of a biomechanical study and the short-term outcome of a clinical study, as well as to determine the usefulness of this system. Methods The Tadpole system® lumbar spinal fusion is a hook-and-rod system according to which the spine is stabilized using 2 sets of 2 spinous processes each that are held in place by 4 hooks tandemly connected to a rod. The biomechanical study was done using 5 human lumbar cadaveric spines, and the range of motion (ROM) was examined in a non-treatment model, an injured model, a pedicle screw fixation model and a Tadpole system® model. For the short-term clinical study the Tadpole system® was used in 31 patients, and the factors analyzed were operation time, time required for spinal instrumentation, amount of intraoperative bleeding, postoperative improvement rate of the Japanese Orthopaedic Association (JOA) score for lumbar spinal disorders, instrumentation failure, spinous process fracture, spinal fluid leakage, nerve root injury, postoperative infection, and bone fusion 2 years after the operation. Results The ROM in the Tadpole system® model was slightly bigger than that in the pedicle screw fixation model, but smaller than that in the normal control model. These biomechanical data indicated that the Tadpole system® provided fairly good stability. The mean operation time was 79 min, the mean time required for spinal instrumentation was 8 min, and the mean amount of intraoperative bleeding was 340 mL. The mean postoperative improvement rate of JOA score was 70.9 ± 24.8%. Instrumentation failure (dislocation of a hook) occurred in one patient, and none of the patients developed spinous process fracture, spinal fluid

  17. Lumbar spinal extradural angiolipomas. Two case reports.

    PubMed

    Dogan, Seref; Arslan, Erhan; Sahin, Soner; Aksoy, Kaya; Aker, Sibel

    2006-03-01

    Spinal extradural angiolipomas are benign tumors mostly localized in the thoracic region. A 50-year-old woman and a 36-year-old man presented with rare lumbar spinal angiolipoma manifesting as low back pain but without neurological signs. Magnetic resonance imaging showed lumbar extradural tumors at the L4-5 and L1-2 levels, respectively. Each patient underwent complete surgical resection of the epidural tumors. Histological examination revealed characteristics of angiolipomas in both tumors. The symptoms of both patients improved postoperatively and no recurrence of the tumors was found 1 year after surgery.

  18. Chronic prostatitis in spinal cord injury patients.

    PubMed

    Wyndaele, J J

    1985-06-01

    Six spinal cord injury patients with chronic prostatitis were reviewed, all of whom had been treated with an indwelling Foley catheter during the phase of spinal shock. The 3 glass urine specimen test, the bladder wash-out test, a study of antibody coated bacteria and urethrography had limited diagnostic value. A specific diagnostic 5 glass specimen test proved to be useful and reliable. Longterm antibiotic treatment was successful in only one patient. Injection of antibiotics into the prostate gland was ineffective in the five patients in whom it was carried out. During a follow up from 1 to 5 years urological complications were rare in all five patients who remained infected.

  19. Characterization of recovered walking patterns and motor control after contusive spinal cord injury in rats

    PubMed Central

    Hansen, Christopher N; Linklater, William; Santiago, Raquel; Fisher, Lesley C; Moran, Stephanie; Buford, John A; Michele Basso, D

    2012-01-01

    Currently, complete recovery is unattainable for most individuals with spinal cord injury (SCI). Instead, recovery is typically accompanied by persistent sensory and motor deficits. Restoration of preinjury function will likely depend on improving plasticity and integration of these impaired systems. Eccentric muscle actions require precise integration of sensorimotor signals and are predominant during the yield (E2) phase of locomotion. Motor neuron activation and control during eccentric contractions is impaired across a number of central nervous system (CNS) disorders, but remains unexamined after SCI. Therefore, we characterized locomotor recovery after contusive SCI using hindlimb (HL) kinematics and electromyographic (EMG) recordings with specific consideration of eccentric phases of treadmill (TM) walking. Deficits in E2 and a caudal shift of locomotor subphases persisted throughout the 3-week recovery period. EMG records showed notable deficits in the semitendinosus (ST) during yield. Unlike other HL muscles, recruitment of ST changed with recovery. At 7 days, the typical dual-burst pattern of ST was lost and the second burst (ST2) was indistinct. By 21 days, the dual-burst pattern returned, but latencies remained impaired. We show that ST2 burst duration is highly predictive of open field Basso, Beattie, Bresnahan (BBB) scores. Moreover, we found that simple changes in locomotor specificity which enhance eccentric actions result in new motor patterns after SCI. Our findings identify a caudal shift in stepping kinematics, irregularities in E2, and aberrant ST2 bursting as markers of incomplete recovery. These residual impairments may provide opportunities for targeted rehabilitation. PMID:23139900

  20. Spinal efference copy signaling and gaze stabilization during locomotion in juvenile Xenopus frogs.

    PubMed

    von Uckermann, Géraldine; Le Ray, Didier; Combes, Denis; Straka, Hans; Simmers, John

    2013-03-01

    In swimming Xenopus laevis tadpoles, gaze stabilization is achieved by efference copies of spinal locomotory CPG output that produce rhythmic extraocular motor activity appropriate for minimizing motion-derived visual disturbances. During metamorphosis, Xenopus switches its locomotory mechanism from larval tail-based undulatory movements to bilaterally synchronous hindlimb kick propulsion in the adult. The change in locomotory mode leads to body motion dynamics that no longer require conjugate left-right eye rotations for effective retinal image stabilization. Using in vivo kinematic analyses, in vitro electrophysiological recordings and specific CNS lesions, we have investigated spino-extraocular motor coupling in the juvenile frog and the underlying neural pathways to understand how gaze control processes are altered in accordance with the animal's change in body plan and locomotor strategy. Recordings of extraocular and limb motor nerves during spontaneous "fictive" swimming in isolated CNS preparations revealed that there is indeed a corresponding change in spinal efference copy control of extraocular motor output. In contrast to fictive larval swimming where alternating bursts occur in bilateral antagonistic horizontal extraocular nerves, during adult fictive limb-kicking, these motor nerves are synchronously active in accordance with the production of convergent eye movements during the linear head accelerations resulting from forward propulsion. Correspondingly, the neural pathways mediating spino-extraocular coupling have switched from contralateral to strictly ipsilateral ascending influences that ensure a coactivation of bilateral extraocular motoneurons with synchronous left-right limb extensions. Thus, adaptive developmental plasticity during metamorphosis enables spinal CPG-driven extraocular motor activity to match the changing requirements for eye movement control during self-motion.

  1. Effects of Serotonergic Medications on Locomotor Performance in Humans with Incomplete Spinal Cord Injury

    PubMed Central

    Leech, Kristan A.; Kinnaird, Catherine R.

    2014-01-01

    Abstract Incomplete spinal cord injury (iSCI) often results in significant motor impairments that lead to decreased functional mobility. Loss of descending serotonergic (5HT) input to spinal circuits is thought to contribute to motor impairments, with enhanced motor function demonstrated through augmentation of 5HT signaling. However, the presence of spastic motor behaviors in SCI is attributed, in part, to changes in spinal 5HT receptors that augment their activity in the absence of 5HT, although data demonstrating motor effects of 5HT agents that deactivate these receptors are conflicting. The effects of enhancement or depression of 5HT signaling on locomotor function have not been thoroughly evaluated in human iSCI. Therefore, the aim of the current study was to investigate acute effects of 5HT medications on locomotion in 10 subjects with chronic (>1 year) iSCI. Peak overground and treadmill locomotor performance, including measures of gait kinematics, electromyographic (EMG) activity, and oxygen consumption, were assessed before and after single-dose administration of either a selective serotonin reuptake inhibitor (SSRI) or a 5HT antagonist using a double-blinded, randomized, cross-over design. Results indicate that neither medication led to improvements in locomotion, with a significant decrease in peak overground gait speed observed after 5HT antagonists (from 0.8±0.1 to 0.7±0.1 m/s; p=0.01). Additionally, 5-HT medications had differential effects on EMG activity, with 5HT antagonists decreasing extensor activity and SSRIs increasing flexor activity. Our data therefore suggest that acute manipulation of 5HT signaling, despite changes in muscle activity, does not improve locomotor performance after iSCI. PMID:24742292

  2. Methylprednisolone fails to improve functional and histological outcome following spinal cord injury in rats.

    PubMed

    Pereira, José E; Costa, Luís M; Cabrita, António M; Couto, Pedro A; Filipe, Vítor M; Magalhães, Luís G; Fornaro, Michele; Di Scipio, Federica; Geuna, Stefano; Maurício, Ana C; Varejão, Artur S P

    2009-11-01

    Currently, methylprednisolone sodium succinate (MPSS) is the standard treatment following acute spinal cord injury (SCI) as a consequence of the results obtained from the National Acute Spinal Cord Injury Studies. However, many have questioned the efficacy of MPSS because of its marginal effects. Additionally there has been criticism of both study design and statistical interpretation. The functional consequences of experimental SCI have been assessed in many ways. The purpose of this investigation was to determine the effects of MPSS vs. saline solution (SS) following moderate T10 contusion injury in rat. Functional recovery was evaluated using the 21-point Basso, Beattie and Bresnahan (BBB) locomotor recovery scale, the inclined plane, the beam walk, footprint analysis and the horizontal ladder. To optimize the precision and accuracy of functional results we examined the locomotion on a treadmill using three-dimensional (3D) analysis. Stereology was used to estimate the amount of damaged tissue. The results of the traditional functional methods showed that administration of the NASCIS dosage of MPSS following acute spinal cord contusion did not lead to any significant differences in the functional recovery of MPSS- vs. SS-treated animals. More importantly, the results of the 3D kinematic showed that the MPSS administration did not affect the flexion/extension of the hip, knee and ankle joints during the step cycle. Finally, stereological results revealed no statistically significant differences between the two experimental groups. Altogether, our results support data previously reported by several authors, suggesting that MPSS does not lead to improved functional outcome following experimental acute SCI. PMID:19665461

  3. Power regulation of kinematic control inputs for forward flying Drosophila

    NASA Astrophysics Data System (ADS)

    MacFarlane, Kenneth; Faruque, Imraan; Sean Humbert, J.

    2014-12-01

    The choices of insect wing kinematic programs is not well understood, particularly the mechanism by which an insect selects a distortion to achieve flight control. A methodology to evaluate prospective kinematic control inputs is presented based on the reachable states when control actuation was constrained to a unit of power. The method implements a computationally-derived reduced order model of the insect's flight dynamics combined with calculation of power requirement. Four kinematic inputs are evaluated based on this criterion for a Drosophila size insect in forward flight. Stroke bias is shown to be the dominant control input using this power normalized evaluation measure.

  4. Fault tolerant kinematic control of hyper-redundant manipulators

    NASA Technical Reports Server (NTRS)

    Bedrossian, Nazareth S.

    1994-01-01

    Hyper-redundant spatial manipulators possess fault-tolerant features because of their redundant structure. The kinematic control of these manipulators is investigated with special emphasis on fault-tolerant control. The manipulator tasks are viewed in the end-effector space while actuator commands are in joint-space, requiring an inverse kinematic algorithm to generate joint-angle commands from the end-effector ones. The rate-inverse kinematic control algorithm presented in this paper utilizes the pseudoinverse to accommodate for joint motor failures. An optimal scale factor for the robust inverse is derived.

  5. Computational neural learning formalisms for manipulator inverse kinematics

    NASA Technical Reports Server (NTRS)

    Gulati, Sandeep; Barhen, Jacob; Iyengar, S. Sitharama

    1989-01-01

    An efficient, adaptive neural learning paradigm for addressing the inverse kinematics of redundant manipulators is presented. The proposed methodology exploits the infinite local stability of terminal attractors - a new class of mathematical constructs which provide unique information processing capabilities to artificial neural systems. For robotic applications, synaptic elements of such networks can rapidly acquire the kinematic invariances embedded within the presented samples. Subsequently, joint-space configurations, required to follow arbitrary end-effector trajectories, can readily be computed. In a significant departure from prior neuromorphic learning algorithms, this methodology provides mechanisms for incorporating an in-training skew to handle kinematics and environmental constraints.

  6. An adaptive inverse kinematics algorithm for robot manipulators

    NASA Technical Reports Server (NTRS)

    Colbaugh, R.; Glass, K.; Seraji, H.

    1990-01-01

    An adaptive algorithm for solving the inverse kinematics problem for robot manipulators is presented. The algorithm is derived using model reference adaptive control (MRAC) theory and is computationally efficient for online applications. The scheme requires no a priori knowledge of the kinematics of the robot if Cartesian end-effector sensing is available, and it requires knowledge of only the forward kinematics if joint position sensing is used. Computer simulation results are given for the redundant seven-DOF robotics research arm, demonstrating that the proposed algorithm yields accurate joint angle trajectories for a given end-effector position/orientation trajectory.

  7. Percutaneous Radiofrequency Ablation of Painful Spinal Tumors Adjacent to the Spinal Cord with Real-Time Monitoring of Spinal Canal Temperature: A Prospective Study

    SciTech Connect

    Nakatsuka, Atsuhiro Yamakado, Koichiro; Takaki, Haruyuki; Uraki, Junji; Makita, Masashi; Oshima, Fumiyoshi; Takeda, Kan

    2009-01-15

    PurposeTo prospectively evaluate the feasibility, safety, and clinical utility of bone radiofrequency (RF) ablation with real-time monitoring of the spinal canal temperature for the treatment of spinal tumors adjacent to the spinal cord.Materials and MethodsOur Institutional Review Board approved this study. Patients gave informed consent. The inclusion criteria were (a) a painful spinal metastasis and (b) a distance of 1 cm or less between the metastasis and the spinal cord. The thermocouple was placed in the spinal canal under CT fluoroscopic guidance. When the spinal canal temperature reached 45{sup o}C, RF application was immediately stopped. RF ablation was considered technically successful when the procedure was performed without major complications. Clinical success was defined as a fall in the visual analogue scale score of at least 2 points.ResultsTen patients with spinal tumors measuring 3-8 cm (mean, 4.9 {+-} 1.5 cm) were enrolled. The distance between the tumor and the spinal cord was 1-6 mm (mean, 2.4 {+-} 1.6 mm). All procedures were judged technically successful (100%). The spinal canal temperature did not exceed 45{sup o}C in 9 of the 10 patients (90%). In the remaining patient, the temperature rose to 48{sup o}C, resulting in transient neural damage, although RF application was immediately stopped when the temperature reached 45{sup o}C. Clinical success was achieved within 1 week in all patients (100%).ConclusionBone RF ablation with real-time monitoring of the spinal canal temperature is feasible, safe, and clinically useful for the treatment of painful spinal metastases adjacent to the spinal cord.

  8. Neurocontrol of Movement in Humans With Spinal Cord Injury.

    PubMed

    Dimitrijevic, Milan R; Danner, Simon M; Mayr, Winfried

    2015-10-01

    In this review of neurocontrol of movement after spinal cord injury, we discuss neurophysiological evidences of conducting and processing mechanisms of the spinal cord. We illustrate that external afferent inputs to the spinal cord below the level of the lesion can modify, initiate, and maintain execution of movement in absence or partial presence of brain motor control after chronic spinal cord injury. We review significant differences between spinal reflex activity elicited by single and repetitive stimulation. The spinal cord can respond with sensitization, habituation, and dis-habituation to regular repetitive stimulation. Therefore, repetitive spinal cord reflex activity can contribute to the functional configuration of the spinal network. Moreover, testing spinal reflex activity in individuals with motor complete spinal cord injury provided evidences for subclinical residual brain influence, suggesting the existence of axons traversing the injury site and influencing the activities below the level of lesion. Thus, there are two motor control models of chronic spinal cord injury in humans: "discomplete" and "reduced and altered volitional motor control." We outline accomplishments in modification and initiation of altered neurocontrol in chronic spinal cord injury people with epidural and functional electrical stimulation. By nonpatterned electrical stimulation of lumbar posterior roots, it is possible to evoke bilateral extension as well as rhythmic motor outputs. Epidural stimulation during treadmill stepping shows increased and/or modified motor activity. Finally, volitional efforts can alter epidurally induced rhythmic activities in incomplete spinal cord injury. Overall, we highlight that upper motor neuron paralysis does not entail complete absence of connectivity between cortex, brain stem, and spinal motor cells, but there can be altered anatomy and corresponding neurophysiological characteristics. With specific input to the spinal cord below the level

  9. Relationships between joint motion and facet joint capsule strain during cat and human lumbar spinal motions

    PubMed Central

    Ianuzzi, Allyson; Pickar, Joel G; Khalsa, Partap S

    2011-01-01

    Objective The lumbar facet joint capsule (FJC) is innervated with mechanically sensitive neurons and is thought to contribute to proprioception and pain. Biomechanical investigations of the FJC have commonly used human cadaveric spines, while combined biomechanical and neurophysiological studies have typically used non-human animal models. The purpose of this study was develop mathematical relationships describing vertebral kinematics and facet joint capsule strain in cat and human lumbar spine specimens during physiological spinal motions in order to facilitate future efforts at understanding the mechanosensory role of the FJC. Methods Cat lumbar spine specimens were tested during extension, flexion and lateral bending. Joint kinematics and FJC principal strain were measured optically. FJC strain-intervertebral angle (IVA) regression relationships were established for the three most caudal lumbar joints using cat (current study) and human (prior study) data. FJC strain-IVA relationships were utilized to estimate cat and human spine kinematics that corresponded to published sensory neuron response thresholds for low threshold mechanoreceptors (5% and 10%). Results Significant linear relationships between IVA and strain were observed for both human and cat during motions that produced tension in the FJCs (p<0.01). During motions that produced tension in the FJCs, the models predicted that FJC strain magnitudes corresponding to published sensory neuron response thresholds would be produced by IVA magnitudes within the physiological range of lumbar motion. Conclusions Data from the current study support the proprioceptive role of lumbar spine FJC and low threshold mechanoreceptive afferents, and can be utilized in interpreting combined neurophysiological and biomechanical studies of cat lumbar spines. PMID:21875516

  10. A comprehensive three-dimensional dynamic model of the human head and trunk for estimating lumbar and cervical joint torques and forces from upper body kinematics.

    PubMed

    Vette, Albert H; Yoshida, Takashi; Thrasher, T Adam; Masani, K; Popovic, Milos R

    2012-06-01

    Linked-segment representations of human body dynamics have been used extensively in biomechanics, ergonomics, and rehabilitation research to systemize thinking, make predictions, and suggest novel experiments. In the scope of upper body biomechanics, these models play an even more essential role as the human spine dynamics are difficult to study in vivo. No study exists to date, however, that specifically disseminates the technical details of a comprehensive three-dimensional model of the upper body for the purpose of estimating spinal joint torques and forces for a wide range of scenarios. Consequently, researchers are still bound to develop and implement their own models. Therefore, the objective of this study was to design a dynamic model of the upper body that can comprehensively estimate spinal joint torques and forces from upper body kinematics. The proposed three-dimensional model focuses on the actions of the lumbar and cervical vertebrae and consists of five lumbar segments (L1 to L5), the thorax, six cervical segments (C2 to C7), and the head. Additionally, the model: (1) is flexible regarding the kinematic nature of the spinal joints (free, constrained, or fixed); (2) incorporates all geometric and mass-inertia parameters from a single, high-resolution source; and (3) can be feasibly implemented via different inverse dynamics formulations. To demonstrate its practicality, the model was finally employed to estimate the lumbar and cervical joint torques during perturbed sitting using experimental motion data. Considering the growing importance of mathematical predictions, the developed model should become an important resource for researchers in different fields.

  11. Structure and kinematics of the Bootes filament

    NASA Astrophysics Data System (ADS)

    Nasonova, O.; Karachentsev, I.; Karachentseva, V.

    2016-10-01

    Bootes filament of galaxies is a dispersed chain of groups residing on sky between the Local Void and the Virgo cluster. We consider a sample of 361 galaxies inside the sky area of RA = 13h0...18h.5 and Dec = .5°... + 10° with radial velocities VLG < 2000 km/s to clarify its structure and kinematics. In this region, 161 galaxies have individual distance estimates. We use these data to draw the Hubble relation for galaxy groups, pairs as well as the field galaxies, and to examine the galaxy distribution on peculiar velocities. Our analysis exposes the known Virgo-centric infall at RA < 14h and some signs of outflow from the Local Void at RA > 17h. According to the galaxy grouping criterion, this complex contains the members of 13 groups, 11 pairs and 140 field galaxies. The most prominent group is dominated by NGC 5846. The Bootes filament contains the total stellar mass of 2.7 ×1012 M⊙ and the total virial mass of 9.07×1013 M⊙, having the average density of dark matter to be Ωm = 0.09, i.e. a factor three lower than the global cosmic value.

  12. Kinematic analysis of rope skipper's stability

    NASA Astrophysics Data System (ADS)

    Ab Ghani, Nor Atikah; Rambely, Azmin Sham

    2014-06-01

    There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.

  13. Turbulent Particle Pair Diffusion Using Kinematic Simulations

    NASA Astrophysics Data System (ADS)

    Malik, Nadeem

    2015-11-01

    Sweeping errors in Kinematic Simulations (KS) have been shown to be negligible in turbulent flows with extended inertial subranges up to at least 1 in KS may therefore be a genuine effect, challenging previous assumptions that in turbulence with generalized power-law energy spectra, E (k) ~k-p for 1 <= 3, locality would lead to, K ~σΔγ , where σΔ = [ <Δ2 > ]1/2 , Δ is the pair separation, v is the pair relative velocity, < > is the ensemble average, and γ = (1 + p) / 2 . For Kolmogorov turbulence this gives, K ~σΔ4 / 3 . A new analysis, supported by KS confirms that both local and non-local effects govern the pair diffusion process, leading to, K ~σΔγp , where now γp > γ for Kolmogorov turbulence, K ~σΔ1 . 53 . Thus non-local diffusional processes cannot be neglected, and this may have important consequences for the general theory of turbulence. The author acknowledge financial support from SABIC, #SB101011.

  14. Growth rate degeneracies in kinematic dynamos

    NASA Astrophysics Data System (ADS)

    Favier, B.; Proctor, M. R. E.

    2013-09-01

    We consider the classical problem of kinematic dynamo action in simple steady flows. Due to the adjointness of the induction operator, we show that the growth rate of the dynamo will be exactly the same for two types of magnetic boundary conditions: the magnetic field can be normal (infinite magnetic permeability, also called pseudovacuum) or tangent (perfect electrical conductor) to the boundaries of the domain. These boundary conditions correspond to well-defined physical limits often used in numerical models and relevant to laboratory experiments. The only constraint is for the velocity field u to be reversible, meaning there exists a transformation changing u into -u. We illustrate this surprising property using S2T2 type of flows in spherical geometry inspired by [Dudley and James, Proc. R. Soc. London A1364-502110.1098/rspa.1989.0112 425, 407 (1989)]. Using both types of boundary conditions, it is shown that the growth rates of the dynamos are identical, although the corresponding magnetic eigenmodes are drastically different.

  15. Feeding underground: kinematics of feeding in caecilians.

    PubMed

    Herrel, Anthony; Measey, G John

    2012-11-01

    Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm sec(-1). Although gape cycles are often slow (0.67 ± 0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8 ± 18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians.

  16. Bat flight: aerodynamics, kinematics and flight morphology.

    PubMed

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. PMID:25740899

  17. Scapulothoracic kinematics during tennis forehand drive.

    PubMed

    Rogowski, Isabelle; Creveaux, Thomas; Chèze, Laurence; Dumas, Raphaël

    2014-06-01

    Scapular dyskinesis is recognized as an abnormality in the kinetic chain; yet, there has been little research quantifying scapular motion during sport tasks. Tennis forehand drives of eight highly skilled tennis players were studied to assess the scapulothoracic kinematics and evaluate repeatability using video-based motion analysis. Scapulothoracic downward/upward rotation, posterior/anterior tilt, and internal/external rotation were computed using an acromial marker cluster. On average, the upward rotation, anterior tilt, and internal rotation varied from 1 degrees to 26 degrees, from 7 degrees to 32 degrees, and from 42 degrees to 100 degrees, respectively, during the tennis forehand drive. During the backswing and forward swing phases of the forehand stroke, small changes were observed for the three scapular angle values, while all angles increased rapidly during the follow-through phase. This suggests that the tennis forehand drive may contribute to scapula dyskinesis, mainly due to the great amplitude in scapulothoracic anterior tilt and internal rotation observed during the follow-through phase. Knowledge of normal scapula motion during sport tasks performed at high velocity could improve the understanding of various sport-specific adaptations and pathologies. PMID:25123001

  18. On the Kinematics of Undulator Girder Motion

    SciTech Connect

    Welch, J; /SLAC

    2011-08-18

    The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

  19. Kinematic mental simulations in abduction and deduction

    PubMed Central

    Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N.

    2013-01-01

    We present a theory, and its computer implementation, of how mental simulations underlie the abductions of informal algorithms and deductions from these algorithms. Three experiments tested the theory’s predictions, using an environment of a single railway track and a siding. This environment is akin to a universal Turing machine, but it is simple enough for nonprogrammers to use. Participants solved problems that required use of the siding to rearrange the order of cars in a train (experiment 1). Participants abduced and described in their own words algorithms that solved such problems for trains of any length, and, as the use of simulation predicts, they favored “while-loops” over “for-loops” in their descriptions (experiment 2). Given descriptions of loops of procedures, participants deduced the consequences for given trains of six cars, doing so without access to the railway environment (experiment 3). As the theory predicts, difficulty in rearranging trains depends on the numbers of moves and cars to be moved, whereas in formulating an algorithm and deducing its consequences, it depends on the Kolmogorov complexity of the algorithm. Overall, the results corroborated the use of a kinematic mental model in creating and testing informal algorithms and showed that individuals differ reliably in the ability to carry out these tasks. PMID:24082090

  20. SHIELD: Neutral Gas Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    McNichols, Andrew; Teich, Yaron; Cannon, John M.; SHIELD Team

    2016-01-01

    The "Survey of HI in Extremely Low-mass Dwarfs" (SHIELD) is a multiwavelength, legacy-class observational study of 12 low-mass dwarf galaxies discovered in Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Here we present new results of detailed kinematic analyses of these systems using multi-configuration, high spatial (˜300 pc) and spectral (0.82 - 2.46 km s-1 ch-1) resolution HI observations from the Karl G. Jansky Very Large Array. For each source, we produce velocity fields and dispersion maps using different spatial and spectral resolution representations of the data in order to attempt derivation of an inclination-corrected rotation curve. While both two- and three-dimensional fitting techniques are employed, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make multiple position-velocity cuts across each galaxy to determine the maximum circular rotation velocity (≤ 30 km-1 for the survey population). Baryonic masses are calculated using single-dish H I fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are contextualized on the baryonic Tully-Fisher relation.Support for this work was provided by NSF grant AST-1211683 to JMC at Macalester College.

  1. Virtual sine arm kinematic mount system

    SciTech Connect

    Xu, Z.; Randall, K.J.

    1997-09-01

    A novel kinematic mount system for a vertical focusing mirror of the soft x-ray spectroscopy beamline at the Advanced Photon Source is described. The system contains three points in a horizontal plane. Each point consists of two horizontal linear precision stages, a spherical ball bearing, and a vertical precision stage. The horizontal linear stages are aligned orthogonally and are conjoined by a spherical ball bearing, supported by the vertical linear stage at each point. The position of each confined horizontal stage is controlled by a motorized micrometer head by spring-loading the flat tip of the micrometer head onto a tooling ball fixing on the carriage of the stage. A virtual sine arm is formed by tilting the upstream horizontal stage down and the two downstream horizontal stages up by a small angle. The fine pitch motion is achieved by adjusting the upstream stage. This supporting structure is extremely steady due to a relatively large span across the supporting points and yields extremely high resolution on the pitch motion. With a one degree tilt and a microstepping motor, the authors achieved a 0.4 nanoradian resolution on the mirror pitch motion.

  2. Kinematic structure of OH/IR stars

    NASA Astrophysics Data System (ADS)

    Sun, J.; Kwok, S.

    1987-10-01

    A kinematic model is constructed for 1612 MHz OH maser emssion in OH/IR stars. The spatial distributions of OH maser intensity are calculated from a model of spherically-symmetric uniformly-expanding circumstellar shell. By comparing VLA/VLBI maps of OH/IR stars with model results, the acceptable range of combination of physical parameters M/Ve, (nH2)max, (nH2)min, fOH = [nOH]/[nH2] are derived. The theoretical relations between OH shell radius R0 and mass loss rate Mand between OH maser luminosity LOH and Mare also obtained. These relations are in good agreement with empirical relations established by Bowers et al. (1983) and Baud et al. (1983). The ranges of (nH2)max and (nOH)min under different Mrequired for operating saturated 1612 MHz OH masers are also discussed. The authors find that the OH emission phase can last over 1000 years after the termination of the asymptotic giant branch and many protoplanetary nebulae may have the characteristics of OH/IR stars.

  3. Kinematic dynamo, supersymmetry breaking, and chaos

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Igor V.; Enßlin, Torsten A.

    2016-04-01

    The kinematic dynamo (KD) describes the growth of magnetic fields generated by the flow of a conducting medium in the limit of vanishing backaction of the fields onto the flow. The KD is therefore an important model system for understanding astrophysical magnetism. Here, the mathematical correspondence between the KD and a specific stochastic differential equation (SDE) viewed from the perspective of the supersymmetric theory of stochastics (STS) is discussed. The STS is a novel, approximation-free framework to investigate SDEs. The correspondence reported here permits insights from the STS to be applied to the theory of KD and vice versa. It was previously known that the fast KD in the idealistic limit of no magnetic diffusion requires chaotic flows. The KD-STS correspondence shows that this is also true for the diffusive KD. From the STS perspective, the KD possesses a topological supersymmetry, and the dynamo effect can be viewed as its spontaneous breakdown. This supersymmetry breaking can be regarded as the stochastic generalization of the concept of dynamical chaos. As this supersymmetry breaking happens in both the diffusive and the nondiffusive cases, the necessity of the underlying SDE being chaotic is given in either case. The observed exponentially growing and oscillating KD modes prove physically that dynamical spectra of the STS evolution operator that break the topological supersymmetry exist with both real and complex ground state eigenvalues. Finally, we comment on the nonexistence of dynamos for scalar quantities.

  4. GLOBAL H I KINEMATICS IN DWARF GALAXIES

    SciTech Connect

    Stilp, Adrienne M.; Dalcanton, Julianne J.; Warren, Steven R.; Skillman, Evan; Ott, Juergen; Koribalski, Baerbel

    2013-03-10

    H I line widths are typically interpreted as a measure of interstellar medium turbulence, which is potentially driven by star formation (SF). In an effort to better understand the possible connections between line widths and SF, we have characterized H I kinematics in a sample of nearby dwarf galaxies by co-adding line-of-sight spectra after removing the rotational velocity to produce average global H I line profiles. These ''superprofiles'' are composed of a central narrow peak ({approx}6-10 km s{sup -1}) with higher-velocity wings to either side that contain {approx}10%-15% of the total flux. The superprofiles are all very similar, indicating a universal global H I profile for dwarf galaxies. We compare characteristics of the superprofiles to various galaxy properties, such as mass and measures of SF, with the assumption that the superprofile represents a turbulent peak with energetic wings to either side. We use these quantities to derive average scale heights for the sample galaxies. When comparing to physical properties, we find that the velocity dispersion of the central peak is correlated with ({Sigma}{sub HI}). The fraction of mass and characteristic velocity of the high-velocity wings are correlated with measures of SF, consistent with the picture that SF drives surrounding H I to higher velocities. While gravitational instabilities provide too little energy, the SF in the sample galaxies does provide enough energy through supernovae, with realistic estimates of the coupling efficiency, to produce the observed superprofiles.

  5. Bat flight: aerodynamics, kinematics and flight morphology.

    PubMed

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace.

  6. Feeding underground: kinematics of feeding in caecilians.

    PubMed

    Herrel, Anthony; Measey, G John

    2012-11-01

    Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm sec(-1). Although gape cycles are often slow (0.67 ± 0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8 ± 18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians. PMID:22927194

  7. The [N II] Kinematics of R Aquarii

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Vogel, S. N.; VanBuren, D.; Strong, J. P.; Lyon, R. G.; Dorband, J. E.

    1998-01-01

    We report a kinematic study of the symbiotic star system R Aqr derived from [N H]lambda 6584 emission observations with a Fabry-Perot imaging spectrometer. The [N II] spatial structure of the R Aqr jet, first observed circa 1977, and surrounding hourglass-shaped nebulosity, due to an explosion approximately 660 years ago, are derived from 41 velocity planes spaced at approximately 12 km/s intervals. Fabry-Perot imagery shows the elliptical nebulosity comprising the waist of the hourglass shell is consistent with a circular ring expanding radially at 55 km/s as seen at an inclination angle, i approximately 70 deg. Fabry-Perot imagery shows the two-sided R Aqr jet is collimated flow in opposite directions. The intensity-velocity structure of the strong NE jet component is shown in contrast to the amorphous SW jet component. We offer a idealized schematic model for the R Aqr jet motion which results in a small-scale helical structure forming around a larger-scale helical path. The implications of such a jet model are discussed. We present a movie showing a side-by-side comparison of the spatial structure of the model and the data as a function of the 41 velocity planes.

  8. Scapulothoracic kinematics during tennis forehand drive.

    PubMed

    Rogowski, Isabelle; Creveaux, Thomas; Chèze, Laurence; Dumas, Raphaël

    2014-06-01

    Scapular dyskinesis is recognized as an abnormality in the kinetic chain; yet, there has been little research quantifying scapular motion during sport tasks. Tennis forehand drives of eight highly skilled tennis players were studied to assess the scapulothoracic kinematics and evaluate repeatability using video-based motion analysis. Scapulothoracic downward/upward rotation, posterior/anterior tilt, and internal/external rotation were computed using an acromial marker cluster. On average, the upward rotation, anterior tilt, and internal rotation varied from 1 degrees to 26 degrees, from 7 degrees to 32 degrees, and from 42 degrees to 100 degrees, respectively, during the tennis forehand drive. During the backswing and forward swing phases of the forehand stroke, small changes were observed for the three scapular angle values, while all angles increased rapidly during the follow-through phase. This suggests that the tennis forehand drive may contribute to scapula dyskinesis, mainly due to the great amplitude in scapulothoracic anterior tilt and internal rotation observed during the follow-through phase. Knowledge of normal scapula motion during sport tasks performed at high velocity could improve the understanding of various sport-specific adaptations and pathologies.

  9. Thermally Insulating, Kinematic Tensioned-Fiber Suspension

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    2004-01-01

    A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.

  10. Virtual human hand: model and kinematics.

    PubMed

    Peña-Pitarch, Esteban; Falguera, Neus Ticó; Yang, Jingzhou James

    2014-04-01

    The human hand plays an important role in daily life. It is the interface between the human and the exterior world by positioning, orienting, touching and grasping objects. The human hand has multiple degrees of freedom (DOFs) to enable mobility and dexterity. A virtual human hand model can be inserted into CAD (Computer Aided Design) models to assess the manipulation capabilities in the early design stage to reduce design time and cost. Joystick assessment is one of the important design cases. This study is a first step towards a comprehensive hand simulation tool to simulate the manipulation and grasping of objects. This paper presents a novel 25 DOFs' hand skeletal model based on hand anatomy and hand kinematics: (1) joint range of motion, (2) Denavit-Hartenberg method to define the joint relationship and (3) finger workspace determination. Novelty for this hand model includes arching the palm with the four DOFs added in the carpometacarpal and wrist joints for the ring and small fingers.

  11. Software architecture for a kinematically dissimilar master-slave telethesis for exploring rehabilitation applications

    NASA Astrophysics Data System (ADS)

    Wunderlich, Joseph; Chen, Shoupu; Pino, D.; Rahman, Tariq; Harwin, William S.

    1993-12-01

    A person with limited arm and hand function could benefit from technology based on teleoperation principles, particularly where the mechanism provides proprioceptive-like information to the operator giving an idea of the forces encountered in the environment and the positions of the slave robot. A test-bed system is being prepared to evaluate the potential for adapting telemanipulator technology to the needs of people with high level spinal cord injury. This test-bed uses a kinematically dissimilar master and slave pair and will be adaptable to a variety of disabilities. The master will be head controlled and when combined with auxiliary functions will provide the degrees of freedom necessary to attempt any task. In the simplest case, this mapping could be direct, with the slave amplifying the person's movements and forces. It is unrealistic however to expect that the operator will have the range of head movement required for accurate operation of the slave over the full workspace. Neither is it likely that the person will be able to achieve simultaneous and independent control of the 6 or more degrees of freedom required to move the slave. Thus a set of more general mappings must be available that can be chosen to relate to the intrinsic coordinates of the task. The software structure to implement the control of this master-slave system is based on two IBM PC computers linked via an ethernet.

  12. Novalis Stereotactic Radiosurgery for Spinal Dural Arteriovenous Fistula

    PubMed Central

    Sung, Kyoung-Su; Song, Young-Jin

    2016-01-01

    The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system. PMID:27446527

  13. Surgical resection of subependymoma of the cervical spinal cord.

    PubMed

    Tan, Lee A; Kasliwal, Manish K; Mhanna, Nakhle; Fontes, Ricardo B V; Traynelis, Vincent C

    2014-09-01

    Subependymomas can rarely occur in the spinal cord, and account for about 2% of symptomatic spinal cord tumors. It most often occurs in the cervical spinal cord, followed by cervicothoracic junction, thoracic cord and conus medullaris. It often has an eccentric location in the spinal cord and lacks gadolinium enhancement on magnetic resonance imaging. We present a rare case of symptomatic subependymoma of the cervical spinal cord, which underwent successful gross total resection. Surgical pearls and nuances are discussed to help surgeons to avoid potential complications. The video can be found here: http://youtu.be/Rsm9KxZX7Yo. PMID:25175581

  14. KINEMATICAL AND CHEMICAL VERTICAL STRUCTURE OF THE GALACTIC THICK DISK. I. THICK DISK KINEMATICS ,

    SciTech Connect

    Moni Bidin, C.; Carraro, G.; Mendez, R. A.

    2012-03-10

    The variation of the kinematical properties of the Galactic thick disk with Galactic height Z is studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null mean radial motion toward the Galactic anticenter found by other authors, but we find that it changes sign at |Z| = 3 kpc, and the proposed inward motion of the local standard of rest alone cannot explain these observations. The rotational velocity decreases with |Z| by -30 km s{sup -1} kpc{sup -1}, but the data are better represented by a power law with index 1.25, similar to that proposed from the analysis of Sloan Digital Sky Survey data. All the velocity dispersions increase with |Z|, but the vertical gradients are small. The dispersions grow proportionally, with no significant variation of the anisotropy. The ratio {sigma}{sub U}/{sigma}{sub W} = 2 suggests that the thick disk could have formed from a low-latitude merging event. The vertex deviation increases with Galactic height, reaching {approx}20 Degree-Sign at |Z| = 3.5 kpc. The tilt angle also increases, and the orientation of the ellipsoid in the radial-vertical plane is constantly intermediate between the alignment with the cylindrical and the spherical coordinate systems. The tilt angle at |Z| = 2 kpc coincides with the expectations of MOdified Newtonian Dynamics, but an extension of the calculations to higher |Z| is required to perform a conclusive test. Finally, between 2.5 and 3.5 kpc we detect deviations from the linear trend of many kinematical quantities, suggesting that some kinematical substructure could be present.

  15. Kinematical and Chemical Vertical Structure of the Galactic Thick Disk. I. Thick Disk Kinematics

    NASA Astrophysics Data System (ADS)

    Moni Bidin, C.; Carraro, G.; Méndez, R. A.

    2012-03-01

    The variation of the kinematical properties of the Galactic thick disk with Galactic height Z is studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null mean radial motion toward the Galactic anticenter found by other authors, but we find that it changes sign at |Z| = 3 kpc, and the proposed inward motion of the local standard of rest alone cannot explain these observations. The rotational velocity decreases with |Z| by -30 km s-1 kpc-1, but the data are better represented by a power law with index 1.25, similar to that proposed from the analysis of Sloan Digital Sky Survey data. All the velocity dispersions increase with |Z|, but the vertical gradients are small. The dispersions grow proportionally, with no significant variation of the anisotropy. The ratio σU/σW = 2 suggests that the thick disk could have formed from a low-latitude merging event. The vertex deviation increases with Galactic height, reaching ~20° at |Z| = 3.5 kpc. The tilt angle also increases, and the orientation of the ellipsoid in the radial-vertical plane is constantly intermediate between the alignment with the cylindrical and the spherical coordinate systems. The tilt angle at |Z| = 2 kpc coincides with the expectations of MOdified Newtonian Dynamics, but an extension of the calculations to higher |Z| is required to perform a conclusive test. Finally, between 2.5 and 3.5 kpc we detect deviations from the linear trend of many kinematical quantities, suggesting that some kinematical substructure could be present. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (proposal IDs 075.B-0459(A), 077.B-0348(A)). This paper includes data gathered with the 6.5 m Magellan and the duPont Telescopes, located at Las Campanas Observatory, Chile.

  16. Comparison of kinematic responses of the head and spine for children and adults in low-speed frontal sled tests.

    PubMed

    Arbogast, Kristy B; Balasubramanian, Sriram; Seacrist, Thomas; Maltese, Matthew R; García-España, J Felipe; Hopely, Terrence; Constans, Eric; Lopez-Valdes, Francisco J; Kent, Richard W; Tanji, Hiromasa; Higuchi, Kazuo

    2009-11-01

    Previous research has suggested that the pediatric ATD spine, developed from scaling the adult ATD spine, may not adequately represent a child's spine and thus may lead to important differences in the ATD head trajectory relative to a human. To gain further insight into this issue, the objectives of this study were, through non-injurious frontal sled tests on human volunteers, to 1) quantify the kinematic responses of the restrained child's head and spine and 2) compare pediatric kinematic responses to those of the adult. Low-speed frontal sled tests were conducted using male human volunteers (20 subjects: 6-14 years old, 10 subjects: 18-40 years old), in which the safety envelope was defined from an amusement park bumper-car impact. Each subject was restrained by a custom-fit lap and shoulder belt system and photo-reflective targets were attached to a tight-fitting cap worn on the head or adhered to the skin overlying skeletal landmarks on the head, spine, shoulders, sternum, and legs. A 3-D near-infrared target tracking system quantified the position of the following markers: head top, external auditory meatus, nasion, opisthocranion, C4, T1, T4, and T8. Trajectory data were normalized by subject seated height and head and spine rotations were calculated. The Generalized Estimating Equations method was used to determine the effect of age and key anthropometric measures on marker excursion. For all markers, the normalized forward excursion significantly decreased with age and all spinal markers moved upward due to a combination of rigid body rotation and spinal flexion with lesser upward movement with age. The majority of the spine flexion occurred at the base of the neck not in the upper cervical spine and the magnitude of flexion was greatest for the youngest subjects. Additional flexion occurred in the thoracic spine as well. Our findings indicate that the primary factor governing the differences in normalized head and spinal trajectories between the various

  17. Surgical management of multilevel cervical spinal stenosis and spinal cord injury complicated by cervical spine fracture

    PubMed Central

    2014-01-01

    Background There are few reports regarding surgical management of multilevel cervical spinal stenosis with spinal cord injury. Our purpose is to evaluate the safety and feasibility of open-door expansive laminoplasty in combination with transpedicular screw fixation for the treatment of multilevel cervical spinal stenosis and spinal cord injury in the trauma population. Methods This was a retrospective study of 21 patients who had multilevel cervical spinal stenosis and spinal cord injury with unstable fracture. An open-door expansive posterior laminoplasty combined with transpedicular screw fixation was performed under persistent intraoperative skull traction. Outcome measures included postoperative improvement in Japanese Orthopedic Association (JOA) score and incidence of complications. Results The average operation time was 190 min, with an average blood loss of 437 ml. A total of 120 transpedicular screws were implanted into the cervical vertebrae between vertebral C3 and C7, including 20 into C3, 34 into C4, 36 into C5, 20 into C6, and 10 into C7. The mean preoperative JOA score was 3.67 ± 0.53. The patients were followed for an average of 17.5 months, and the average JOA score improved to 8.17 ± 1.59, significantly higher than the preoperative score (t = 1.798, P < 0.05), with an average improvement of 44.7 ± 11.7%. Postoperative complications in four patients included cerebrospinal fluid leakage, delayed wound healing, pulmonary infection, and urinary system infection. All four patients were responsive to antibiotic treatment; one died from respiratory failure 3 months postoperatively. Conclusions The open-door expansive laminoplasty combined with posterior transpedicular screw fixation is feasible for treating multilevel cervical spinal stenosis and spinal cord injury complicated by unstable fracture. Its advantages include minimum surgical trauma, less intraoperative blood loss, and satisfactory stable supportive effect for

  18. Spinal Cord and Spinal Nerve Root Involvement (Myeloradiculopathy) in Tuberculous Meningitis

    PubMed Central

    Gupta, Rahul; Garg, Ravindra Kumar; Jain, Amita; Malhotra, Hardeep Singh; Verma, Rajesh; Sharma, Praveen Kumar

    2015-01-01

    Abstract Most of the information about spinal cord and nerve root involvement in tuberculous meningitis is available in the form of isolated case reports or case series. In this article, we evaluated the incidence, predictors, and prognostic impact of spinal cord and spinal nerve root involvement in tuberculous meningitis. In this prospective study, 71 consecutive patients of newly diagnosed tuberculous meningitis were enrolled. In addition to clinical evaluation, patients were subjected to magnetic resonance imaging (MRI) of brain and spine. Patients were followed up for at least 6 months. Out of 71 patients, 33 (46.4%) had symptoms/signs of spinal cord and spinal nerve root involvement, 22 (30.9%) of whom had symptoms/signs at enrolment. Eleven (15.4%) patients had paradoxical involvement. Paraparesis was present in 22 (31%) patients, which was of upper motor neuron type in 6 (8.4%) patients, lower motor neuron type in 10 (14%) patients, and mixed type in 6 (8.4%) patients. Quadriparesis was present in 3 (4.2%) patients. The most common finding on spinal MRI was meningeal enhancement, seen in 40 (56.3%) patients; in 22 (30.9%), enhancement was present in the lumbosacral region. Other MRI abnormalities included myelitis in 16 (22.5%), tuberculoma in 4 (5.6%), cerebrospinal fluid (CSF) loculations in 4 (5.6%), cord atrophy in 3 (4.2%), and syrinx in 2 (2.8%) patients. The significant predictor associated with myeloradiculopathy was raised CSF protein (>250 mg/dL). Myeloradiculopathy was significantly associated with poor outcome. In conclusion, spinal cord and spinal nerve root involvement in tuberculous meningitis is common. Markedly raised CSF protein is an important predictor. Patients with myeloradiculopathy have poor outcome. PMID:25621686

  19. Treadmill step training promotes spinal cord neural plasticity after incomplete spinal cord injury

    PubMed Central

    Sun, Tiansheng; Ye, Chaoqun; Wu, Jun; Zhang, Zhicheng; Cai, Yanhua; Yue, Feng

    2013-01-01

    A large body of evidence shows that spinal circuits are significantly affected by training, and that intrinsic circuits that drive locomotor tasks are located in lumbosacral spinal segments in rats with complete spinal cord transection. However, after incomplete lesions, the effect of treadmill training has been debated, which is likely because of the difficulty of separating spontaneous stepping from specific training-induced effects. In this study, rats with moderate spinal cord contusion were jected to either step training on a treadmill or used in the model (control) group. The treadmill training began at day 7 post-injury and lasted 20 ± 10 minutes per day, 5 days per week for 10 weeks. The speed of the treadmill was set to 3 m/min and was increased on a daily basis according to the tolerance of each rat. After 3 weeks of step training, the step training group exhibited a sig-nificantly greater improvement in the Basso, Beattie and Bresnahan score than the model group. The expression of growth-associated protein-43 in the spinal cord lesion site and the number of tyrosine hydroxylase-positive ventral neurons in the second lumbar spinal segment were greater in the step training group than in the model group at 11 weeks post-injury, while the levels of brain-derived neurotrophic factor protein in the spinal cord lesion site showed no difference between the two groups. These results suggest that treadmill training significantly improves functional re-covery and neural plasticity after incomplete spinal cord injury. PMID:25206564

  20. Theoretical Positioning Accuracy for Serial and Parallel Kinematic Structure

    NASA Astrophysics Data System (ADS)

    Kurekova, Eva; Halaj, Martin; Omachelová, Milada; Martišovitš, Ilja

    2014-10-01

    Modern production machines employ complex kinematic structures that shall enhance their performance. As those machines are very sophisticated electro-mechanical structures, their design is time consuming and financially demanding. Therefore, designers search for new possibilities how to estimate future properties of the machine as early as in the design phase. The paper gives a brief introduction to the adoption of methodology of measurement uncertainties into the design of production machines. The adapted methodology enables to estimate the theoretical positioning accuracy of the machine end effector that is one of the important indicators of machine performance. Both serial and parallel kinematic structures are considered in the paper. Methodology and sample calculations of theoretical positioning accuracy are presented for serial kinematic structure (represented by advanced plasma cutting head) and parallel kinematic structure, represented by one specific design named Tricept.