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Sample records for finger joint angle

  1. Neural network committees for finger joint angle estimation from surface EMG signals

    PubMed Central

    Shrirao, Nikhil A; Reddy, Narender P; Kosuri, Durga R

    2009-01-01

    Background In virtual reality (VR) systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG) signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG together with the actual joint angle measurements were obtained while the subject was performing flexion-extension rotation of the index finger at three speeds. Several neural networks were trained to predict the joint angle from the parameters extracted from the SEMG signals. The best networks were selected to form six committees. The neural network committees were evaluated using data from new subjects. Results There was hysteresis in the measured SMEG signals during the flexion-extension cycle. However, neural network committees were able to predict the joint angle with reasonable accuracy. RMS errors ranged from 0.085 ± 0.036 for fast speed finger-extension to 0.147 ± 0.026 for slow speed finger extension, and from 0.098 ± 0.023 for the fast speed finger flexion to 0.163 ± 0.054 for slow speed finger flexion. Conclusion Although hysteresis was observed in the measured SEMG signals, the committees of neural networks were able to predict the finger joint angle from SEMG signals. PMID:19154615

  2. Low-Friction Joint for Robot Fingers

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.

    1985-01-01

    Mechanical linkage allows adjacent parts to move relative to each other with low friction and with no chatter, slipping, or backlash. Low-friction joint of two surfaces in rolling contact, held in alinement by taut flexible bands. No sliding friction or "stick-slip" motion: Only rolling-contact and bending friction within bands. Proposed linkage intended for finger joints in mechanical hands for robots and manipulators.

  3. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  4. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  5. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  6. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  7. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint polymer constrained prosthesis. 888.3230 Section 888.3230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification....

  8. The design and development of a finger joint simulator.

    PubMed

    Joyce, Thomas J

    2016-05-01

    Artificial finger joints lack the long-term clinical success seen with hip and knee prostheses. In part, this can be explained by the challenges of rheumatoid arthritis, a progressive disease which attacks surrounding tissues as well as the joint itself. Therefore, the natural finger joints' biomechanics are adversely affected, and consequently, this imbalance due to subluxing forces further challenges any prosthesis. Many different designs of finger prosthesis have been offered over a period of greater than 50 years. Most of these designs have failed, and it is likely that many of these failures could have been identified had the prostheses been appropriately tested prior to implantation into patients. While finger joint simulators have been designed, arguably only those from a single centre have been able to reproduce clinical-type failures of the finger prostheses tested in them. This article describes the design and development of a finger simulator at Durham University, UK. It explains and justifies the engineering decisions made and thus the evolution of the finger simulator. In vitro results and their linkage to clinical-type failures are outlined to help to show the effectiveness of the simulator. Failures of finger implants in vivo continue to occur, and the need for appropriate in vitro testing of finger prostheses remains strong. PMID:26833697

  9. Simultaneous dislocation of both interphalangeal joints in the middle finger.

    PubMed

    Hester, Thomas; Mahmood, Shoib; Morar, Yateen; Singh, Ravi

    2015-01-01

    Simultaneous dorsal dislocation of both interphalangeal joints (IPJs) in one finger is an uncommon injury. This injury usually occurs on the ulnar side of the hand involving ring and little fingers. We report a case of simultaneous dislocation of both IPJs in the middle finger. Closed reduction and splinting with the IPJs in extension provided a good result with full range of motion at the patient's final follow-up. PMID:25979959

  10. Enhancement of finger motion range with compliant anthropomorphic joint design.

    PubMed

    Çulha, Utku; Iida, Fumiya

    2016-04-01

    Robotic researchers have been greatly inspired by the human hand in the search to design and build adaptive robotic hands. Especially, joints have received a lot of attention upon their role in maintaining the passive compliance that gives the fingers flexibility and extendible motion ranges. Passive compliance, which is the tendency to be employed in motion under the influence of an external force, is the result of the stiffness and the geometrical constraints of the joints that define the direction of the motion. Based on its building elements, human finger joints have multi-directional passive compliance which means that they can move in multiple axis of motion under external force. However, due to their complex anatomy, only simplified biomechanical designs based on physiological analysis are preferred in present day robotics. To imitate the human joints, these designs either use fixed degree of freedom mechanisms which substantially limit the motion axes of compliance, or soft materials that can deform in many directions but hinder the fingers' force exertion capacities. In order to find a solution that lies between these two design approaches, we are using anatomically correct finger bones, elastic ligaments and antagonistic tendons to build anthropomorphic joints with multi-directional passive compliance and strong force exertion capabilities. We use interactions between an index finger and a thumb to show that our joints allow the extension of the range of motion of the fingers up to 245% and gripping size to 63% which can be beneficial for mechanical adaptation in gripping larger objects. PMID:26891473

  11. Dataglove measurement of joint angles in sign language handshapes

    PubMed Central

    Eccarius, Petra; Bour, Rebecca; Scheidt, Robert A.

    2012-01-01

    In sign language research, we understand little about articulatory factors involved in shaping phonemic boundaries or the amount (and articulatory nature) of acceptable phonetic variation between handshapes. To date, there exists no comprehensive analysis of handshape based on the quantitative measurement of joint angles during sign production. The purpose of our work is to develop a methodology for collecting and visualizing quantitative handshape data in an attempt to better understand how handshapes are produced at a phonetic level. In this pursuit, we seek to quantify the flexion and abduction angles of the finger joints using a commercial data glove (CyberGlove; Immersion Inc.). We present calibration procedures used to convert raw glove signals into joint angles. We then implement those procedures and evaluate their ability to accurately predict joint angle. Finally, we provide examples of how our recording techniques might inform current research questions. PMID:23997644

  12. Simultaneous closed dislocation of both interphalangeal joints in one finger.

    PubMed

    Ron, D; Alkalay, D; Torok, G

    1983-01-01

    A rare case of simultaneous dislocation of both interphalangeal joints in one finger in a table-tennis player is presented. The second dislocation took place when the first dislocated joint became the fixed part of the finger as it hit a wall. Treatment was, first, hyperextension to unlock the base of the phalanx, then traction along the phalanx: its base was then pushed into contact with the head of the proximal phalanx. Splinting was applied with the joint in slight flexion. PMID:6823005

  13. Biomimetic myoelectric hand with voluntary control of finger angle and compliance.

    PubMed

    Okuno, R; Akazawa, K; Yoshida, M

    1999-01-01

    The purpose of this study was to develop a new type of myoelectrically controlled biomimetic prosthetic hand which has almost the same dynamics as that of the neuromuscular control system of the finger muscles, and in mechanical properties of the muscles and of the stretch reflex. One of the characteristic features of the neuromuscular control system in man is the increase in the compliance around the joint with decreasing activity of the muscle. Our prosthetic hand consisted of two surface EMG signal processing units, a digital servo system for a DC motor and 1 d.o.f. mechanical hand with three fingers. The dynamics of the neuromuscular control system including variation of the compliance around the joint was realized by using a position control system of the finger movement, force feedback and a variable gain which was modulated by the amplitude of IEMGs (rectified and smoothed EMG signals). EMG signals recorded from a pair of antagonistic muscles used to flex or to extend the wrist were used as control signals. It was shown that the finger angle and the compliance of the prosthetic hand could be controlled voluntarily with EMG signals, and that an amputee could grasp a soft object easily with the prosthetic hand. Utility of the biomimetic prosthetic hand was shown by executing myoelectric control experiments in one healthy subject and one amputee. PMID:10612560

  14. Dorsal finger joint soft tissue loss: two case reports.

    PubMed

    Bervar, M

    2003-01-01

    This article brings our experience, standpoints and management guidelines for early reconstruction of traumatic soft tissue loss on the dorsal aspect of the finger joints, with the aim of preserving acceptable late functional ability of the hand. Two interesting and unusual cases of reconstruction are presented. PMID:14989334

  15. Automatic finger joint synovitis localization in ultrasound images

    NASA Astrophysics Data System (ADS)

    Nurzynska, Karolina; Smolka, Bogdan

    2016-04-01

    A long-lasting inflammation of joints results between others in many arthritis diseases. When not cured, it may influence other organs and general patients' health. Therefore, early detection and running proper medical treatment are of big value. The patients' organs are scanned with high frequency acoustic waves, which enable visualization of interior body structures through an ultrasound sonography (USG) image. However, the procedure is standardized, different projections result in a variety of possible data, which should be analyzed in short period of time by a physician, who is using medical atlases as a guidance. This work introduces an efficient framework based on statistical approach to the finger joint USG image, which enables automatic localization of skin and bone regions, which are then used for localization of the finger joint synovitis area. The processing pipeline realizes the task in real-time and proves high accuracy when compared to annotation prepared by the expert.

  16. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  17. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  18. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  19. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  20. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  1. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  2. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  3. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  4. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  5. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in...

  6. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in...

  7. Static hand gesture recognition based on finger root-center-angle and length weighted Mahalanobis distance

    NASA Astrophysics Data System (ADS)

    Chen, Xinghao; Shi, Chenbo; Liu, Bo

    2016-04-01

    Static hand gesture recognition (HGR) has drawn increasing attention in computer vision and human-computer interaction (HCI) recently because of its great potential. However, HGR is a challenging problem due to the variations of gestures. In this paper, we present a new framework for static hand gesture recognition. Firstly, the key joints of the hand, including the palm center, the fingertips and finger roots, are located. Secondly, we propose novel and discriminative features called root-center-angles to alleviate the influence of the variations of gestures. Thirdly, we design a distance metric called finger length weighted Mahalanobis distance (FLWMD) to measure the dissimilarity of the hand gestures. Experiments demonstrate the accuracy, efficiency and robustness of our proposed HGR framework.

  8. SU-E-T-171: Evaluation of the Analytical Anisotropic Algorithm in a Small Finger Joint Phantom Using Monte Carlo Simulation

    SciTech Connect

    Chow, J; Owrangi, A; Jiang, R

    2014-06-01

    Purpose: This study investigated the performance of the anisotropic analytical algorithm (AAA) in dose calculation in radiotherapy concerning a small finger joint. Monte Carlo simulation (EGSnrc code) was used in this dosimetric evaluation. Methods: Heterogeneous finger joint phantom containing a vertical water layer (bone joint or cartilage) sandwiched by two bones with dimension 2 × 2 × 2 cm{sup 3} was irradiated by the 6 MV photon beams (field size = 4 × 4 cm{sup 2}). The central beam axis was along the length of the bone joint and the isocenter was set to the center of the joint. The joint width and beam angle were varied from 0.5–2 mm and 0°–15°, respectively. Depth doses were calculated using the AAA and DOSXYZnrc. For dosimetric comparison and normalization, dose calculations were repeated in water phantom using the same beam geometry. Results: Our AAA and Monte Carlo results showed that the AAA underestimated the joint doses by 10%–20%, and could not predict joint dose variation with changes of joint width and beam angle. The calculated bone dose enhancement for the AAA was lower than Monte Carlo and the depth of maximum dose for the phantom was smaller than that for the water phantom. From Monte Carlo results, there was a decrease of joint dose as its width increased. This reflected the smaller the joint width, the more the bone scatter contributed to the depth dose. Moreover, the joint dose was found slightly decreased with an increase of beam angle. Conclusion: The AAA could not handle variations of joint dose well with changes of joint width and beam angle based on our finger joint phantom. Monte Carlo results showed that the joint dose decreased with increase of joint width and beam angle. This dosimetry comparison should be useful to radiation staff in radiotherapy related to small bone joint.

  9. Comparative morphometry of coxal joint angles.

    PubMed

    Sugiyama, S; Fujiwara, K

    1997-10-01

    The angles related to the coxal joints were comparatively studied in four-limbed walking animals and two-limbed ones including man and birds. Between animals with both types of walking, no significant difference was observed in the neck-shaft angles (NSA), which was equivalent to the acetabulum angles (ACA) at the connection of the femoral head with the acetabulum. The anteversion angles (AVA) were equivalent to the horizontal ACA. Canine species showed two different forms of the femoral neck with or without modification by the femoral AVA, probably being breed-specific and nutrition-dependent. In the narrow-striped wallaby as well as avian species, the femoral head showed a postversion with a minus-version angle for lifting the body axis in the frontal and upward direction to hold the whole body weight on the hind-limbs, in particular at the anterior part of the acetabulum. In man, the connection between the femur and acetabulum greatly varied among individuals, possibly according to differences in the life style. PMID:9353634

  10. Rotatory subluxation of the metacarpophalangeal index finger joint: a case report.

    PubMed

    Teo, Ken; Berger, Anthony

    2013-01-01

    We report a case of rotatory subluxation of the metacarpophalangeal joint (MCPJ) of the finger. A 40-year-old man sustained an open injury to his index finger following an explosive injury. Radiographs showed rotatory subluxation of the index finger MCPJ. The index finger extensor digitorium was found interposed in the MCPJ, with a complete tear of the radial collateral ligament. Treatment was by open reduction and repair of the collateral ligament and the extensor tendon. A high level of clinical suspicion is needed to diagnose this entity. PMID:23413862

  11. Fractal dimension and unscreened angles measured for radial viscous fingering.

    PubMed

    Praud, Olivier; Swinney, Harry L

    2005-07-01

    We have examined fractal patterns formed by the injection of air into oil in a thin (0.127 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell), for pressure differences in the range 0.25 < or = DeltaP < or = 1.75 atm. We find that an asymptotic structure is reached at large values of the ratio r/b, where r is the pattern radius and b the gap between the plates. Both the driving force and the size of the pattern, which reaches r/b = 900, are far larger than in past experiments. The fractal dimension D0 of the pattern for large r/b is 1.70 +/- 0.02. Further, the generalized dimensions D(q) of the pattern are independent of q , D(q) approximately 1.70 for the range examined, -11 < q < 17; thus the pattern is self-similar within the experimental uncertainty. The results for D(q) agree well with recent calculations for diffusion-limited aggregation (DLA) clusters. We have also measured the probability distribution of unscreened angles. At late times, the distribution approaches a universal (i.e., forcing and size-independent) asymptotic form that has mean 145 degrees Celsius and standard deviation 36 degrees Celsius. These results indicate that the distribution function for the unscreened angle is an invariant property of the growth process. PMID:16089960

  12. Joint sense, muscle sense, and their combination as position sense, measured at the distal interphalangeal joint of the middle finger.

    PubMed Central

    Gandevia, S C; McCloskey, D I

    1976-01-01

    1. An anatomical peculiarity allows the hand to be positioned so that the terminal phalanx of the middle finger cannot be moved by voluntary effort. When positioned in this way only joint and cutaneous mechanisms subserve position sense. By altering the position of the hand the muscles are again engaged and able to move the finger. Moving the joint then also excites muscular afferents. 2. The position sense of twelve subjects was assessed with and without engagement of the muscles at the joint. Three tests were used in which either angular displacement, angular velocity or duration of displacement were held constant. 3. When muscular attachment was restored, performance in all tests was greatly enhanced. As engagement of the muscles caused little change in the 'stiffness' of the joint, it is unlikely that the improved performance resulted from increased discharges from the joint receptors. Cutaneous mechanisms are unlikely to mediate this improvement as they are likely to have been unaffected by engagement of muscles. It is concluded that intramuscular receptors are partly responsible for normal position sense. 4. In seven of the twelve subjects the test finger was anaesthetized to isolate the contribution of intramuscular receptors. This muscle sense was variable. In some subjects it provided accurate kinaesthetic information but in others the information was crude. If with the test finger anaesthetized subjects exerted voluntary tension with the muscles that move the joint the muscle sense was improved. Images Plate 1 PMID:978533

  13. Noninvasively measuring oxygen saturation of human finger-joint vessels by multi-transducer functional photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Deng, Zijian; Li, Changhui

    2016-06-01

    Imaging small blood vessels and measuring their functional information in finger joint are still challenges for clinical imaging modalities. In this study, we developed a multi-transducer functional photoacoustic tomography (PAT) system and successfully imaged human finger-joint vessels from ˜1 mm to <0.2 mm in diameter. In addition, the oxygen saturation (SO2) values of these vessels were also measured. Our results demonstrate that PAT can provide both anatomical and functional information of individual finger-joint vessels with different sizes, which might help the study of finger-joint diseases, such as rheumatoid arthritis.

  14. Menstrual cyclicity of finger joint size and grip strength in patients with rheumatoid arthritis.

    PubMed Central

    Rudge, S R; Kowanko, I C; Drury, P L

    1983-01-01

    Daily measurements of finger joint size, grip strength, and body weight have been made throughout 2 complete menstrual cycles in 7 female patients with rheumatoid arthritis and 6 healthy female controls. Sine wave analysis showed significant individual cyclical rhythms (p less than 0.05) for finger joint size (5 patients, 4 controls), nude weight (5 patients, 3 controls), and grip strength (4 patients, 3 controls). In addition analysis of group data, on the assumption of a 28-day cycle, showed a significant cycle for grip strength in the rheumatoid patients, with a nadir at 28 days. In the normal subjects much of the cyclical variation in finger joint size could be explained by changes in weight (median 49.5%), but this was not so in patients with rheumatoid arthritis (median 2.8%). These findings suggest the existence of a cyclical variation in disease activity in rheumatoid arthritis. PMID:6882039

  15. Novel titanium-aluminum joints for cryogenic cold finger structures

    NASA Astrophysics Data System (ADS)

    Meehan, H. M.; Sweet, R. C.

    For optimum performance, the sensors employed in airborne detection and surveillance systems must be maintained at low temperatures. The containing wall of the expansion volume of a Stirling cycle cooler may provide the low temperature surface for mounting the sensors. IR detectors are commonly mounted on copper heat exchanger surfaces. A stainless steel member is employed to thermally isolate and structurally stabilize such surfaces. It is pointed out that the use of an aluminum-titanium cold finger results in a considerable weight reduction. The present investigation is concerned with an attempt to obtain such structures with the aid of a technique involving the casting of molten aluminum onto an appropriately dimensioned and positioned titanium member, taking into account the fact that aluminum readily wets and bonds to clean titanium surfaces. The casting is then machined to provide the form and structure desired. It is concluded that aluminum-titanium cast structures offer good potential for use as cryogenic cold finger assemblies.

  16. Assessment of finger joint inflammation by diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Hielscher, Andreas H.; Klose, Alexander D.; Scheel, Alexander K.; Backhaus, Marina; Netz, Uwe J.; Beuthan, Juergen

    2003-10-01

    Inflammatory processes as they occur during rheumatoid arthritis (RA) lead to changes in the optical properties of joint tissues and fluids. These changes occur early on in the disease process and can potentially be used as diagnostic parameter. In this work we report on in vivo studies involving 12 human subjects, which show the potential of diffuse optical tomographic techniques for the diagnosis of inflammatory processes in proximal interphalangeal (PIP) joints.

  17. Radiologically defined osteoarthrosis in the finger joints of adult residents of Zagreb.

    PubMed

    Cvijetić, S; Dekanić, D; Kurtagić, N; Roić, G

    1994-09-01

    Degenerative changes in the finger joints were studied in 550 Zagreb inhabitants, above the age of 45. The sample was selected by the method of unproportional stratified choice according to age and sex. Radiographs of both hands were taken and osteoarthrosis on the proximal and distal interphalangeal joints was graded according to the five-point Kellgren-Lawrence scale. Body weight, height and arterial blood pressure were measured and occupational work load was evaluated. The prevalence of osteoarthrosis in the finger joints was significantly higher in women (40.9%) than in men (24.8%). It increased with age so that 18.7% of men and 15.0% of women aged 45-54 had finger osteoarthrosis compared to 36.3% of men and 68.2% of women aged 75 and older. Distal interphalangeal joints were more often involved (22.8% of men and 37.9% of women) than the proximal ones (9.7% of men and 19.6% of women). The factors most closely associated with osteoarthrosis were age and body weight. Occupational work load, as classified in this study, was not significantly related to the development of osteoarthrosis, except in the group of housewives, in whom the prevalence of finger arthrosis was greater than in the other groups of women. PMID:7763184

  18. The effect of knee joint angle on torque control.

    PubMed

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque. PMID:19906637

  19. Small Finger Snapping due to Retinacular Ligament Injury at the Level of Proximal Interphalangeal Joint

    PubMed Central

    Lee, Young-Keun; Lee, Jun-Mo; Lee, Malrey

    2015-01-01

    Abstract Pathological snapping secondary to posttraumatic subluxation of the extensor tendon at proximal interphalangeal joint (PIPJ) of the finger is rare. Here, we want to describe a patient with snapping of the left small finger at PIPJ due to retinacular ligament injury. A 24-year-old man was admitted because of a 5-year history of a snapping sound in the left small finger. On examination, the radial side lateral band of the small finger was dislocated volarly at the level PIPJ with flexion of >50°, which was clearly felt over the skin. There was an obvious snapping sound at the time of dislocation. There was no specific radiographic abnormality. With the patient under regional anesthesia, exploration through a zigzag skin incision over the dorsum of the PIPJ revealed that the retinacular ligament complex was injured. We also found a partial tear in PIPJ capsule, through the incision of the injured retinacular ligament complex. We repaired the joint capsule and retinacular ligament complex with prolene 4–0. Postoperatively the small finger was immobilized in a below-elbow plaster splint with full extension of the fingers for 1 week, then dynamic splinting was advised for another 5 weeks and unrestricted full active motion was allowed at the 6th week. At the 6-month follow-up, the patient had regained full range of motion with no discomfort, and there was no sign of recurrence. We stress that when there is snapping over the dorsum of the PIPJ of the finger, the clinician should suspect rupture of the retinacular ligaments, especially in minor trauma patients. Primary repair of retinacular ligaments and dynamic splinting provided satisfactory results without recurrence in our patient. PMID:26091481

  20. Small Finger Snapping due to Retinacular Ligament Injury at the Level of Proximal Interphalangeal Joint

    PubMed Central

    Lee, Young-Keun; Lee, Jun-Mo; Lee, Malrey

    2015-01-01

    Abstract Pathological snapping secondary to posttraumatic subluxation of the extensor tendon at proximal interphalangeal joint (PIPJ) of the finger is rare. Here, we want to describe a patient with snapping of the left small finger at PIPJ due to retinacular ligament injury. A 24-year-old man was admitted because of a 5-year history of a snapping sound in the left small finger. On examination, the radial side lateral band of the small finger was dislocated volarly at the level PIPJ with flexion of >50°, which was clearly felt over the skin. There was an obvious snapping sound at the time of dislocation. There was no specific radiographic abnormality. With the patient under regional anesthesia, exploration through a zigzag skin incision over the dorsum of the PIPJ revealed that the retinacular ligament complex was injured. We also found a partial tear in PIPJ capsule, through the incision of the injured retinacular ligament complex. We repaired the joint capsule and retinacular ligament complex with prolene 4–0. Postoperatively the small finger was immobilized in a below-elbow plaster splint with full extension of the fingers for 1 week, then dynamic splinting was advised for another 5 weeks and unrestricted full active motion was allowed at the 6th week. At the 6-month follow-up, the patient had regained full range of motion with no discomfort, and there was no sign of recurrence. We stress that when there is snapping over the dorsum of the PIPJ of the finger, the clinician should suspect rupture of the retinacular ligaments, especially in minor trauma patients. Primary repair of retinacular ligaments and dynamic splinting provided satisfactory results without recurrence in our patient.

  1. Simultaneous Volar Dislocation of Distal Interphalangeal Joint and Volar Fracture-Subluxation of Proximal Interphalangeal Joint of Little Finger: A New Mechanism of Injury.

    PubMed

    Mozaffarian, Kamran; Bayatpour, Abdollah; Vosoughi, Amir Reza

    2016-10-01

    Simultaneous volar dislocation of distal interphalangeal (DIP) joint and volar fracture-subluxation of proximal interphalangeal (PIP) joint of the same finger has not been reported yet. A 19-year-old man was referred due to pain on the deformed left little finger after a ball injury. Radiographs showed volar dislocation of the DIP joint and dorsal lip fracture of the middle phalanx with volar subluxation of PIP joint of the little finger. This case was unique in terms of the mechanism of injury which was hyperflexion type in two adjacent joints of the same finger. The patient was treated by closed reduction of DIP joint dislocation and open reduction and internal fixation of the PIP joint fracture-subluxation and application of dorsal external fixator due to instability. Finally, full flexion of the PIP joint and full extension of the DIP joint were obtained but with 10 degree extension lag at the PIP joint and DIP joint flexion ranging from 0 degree to 30 degrees. Some loss of motion in small joints of the fingers after hyperflexion injuries should be expected. PMID:27595966

  2. Computer-aided classification of rheumatoid arthritis in finger joints using frequency domain optical tomography

    NASA Astrophysics Data System (ADS)

    Klose, C. D.; Kim, H. K.; Netz, U.; Blaschke, S.; Zwaka, P. A.; Mueller, G. A.; Beuthan, J.; Hielscher, A. H.

    2009-02-01

    Novel methods that can help in the diagnosis and monitoring of joint disease are essential for efficient use of novel arthritis therapies that are currently emerging. Building on previous studies that involved continuous wave imaging systems we present here first clinical data obtained with a new frequency-domain imaging system. Three-dimensional tomographic data sets of absorption and scattering coefficients were generated for 107 fingers. The data were analyzed using ANOVA, MANOVA, Discriminant Analysis DA, and a machine-learning algorithm that is based on self-organizing mapping (SOM) for clustering data in 2-dimensional parameter spaces. Overall we found that the SOM algorithm outperforms the more traditional analysis methods in terms of correctly classifying finger joints. Using SOM, healthy and affected joints can now be separated with a sensitivity of 0.97 and specificity of 0.91. Furthermore, preliminary results suggest that if a combination of multiple image properties is used, statistical significant differences can be found between RA-affected finger joints that show different clinical features (e.g. effusion, synovitis or erosion).

  3. Photoacoustic tomography of the human finger: towards the assessment of inflammatory joint diseases

    NASA Astrophysics Data System (ADS)

    van Es, P.; Biswas, S. K.; Bernelot Moens, H. J.; Steenbergen, W.; Manohar, S.

    2015-03-01

    Inflammatory arthritis is often manifested in finger joints. The growth of new or withdrawal of old blood vessels can be a sensitive marker for these diseases. Photoacoustic (PA) imaging has great potential in this respect since it allows the sensitive and highly resolved visualization of blood. We systematically investigated PA imaging of finger vasculature in healthy volunteers using a newly developed PA tomographic system. We present the PA results which show excellent detail of the vasculature. Vessels with diameters ranging between 100 μm and 1.5 mm are visible along with details of the skin, including the epidermis and the subpapillary plexus. The focus of all the studies is at the proximal and distal interphalangeal joints, and in the context of ultimately visualizing the inflamed synovial membrane in patients. This work is important in laying the foundation for detailed research into PA imaging of the phalangeal vasculature in patients suffering from rheumatoid arthritis.

  4. Integrated photoacoustic and diffuse optical tomography system for imaging of human finger joints in vivo.

    PubMed

    Xi, Lei; Jiang, Huabei

    2016-03-01

    In this study, we developed a dual-modality tomographic system that integrated photoacoustic imaging (PAI) and diffuse optical tomography (DOT) into a single platform for imaging human finger joints with fine structures and associated optical properties. In PAI, spherical focused transducers were utilized to collect acoustic signals, and the concept of virtual detector was applied in a conventional back-projection algorithm to improve the image quality. A finite-element based reconstruction algorithm was employed to quantitatively recover optical property distribution in the objects for DOT. The phantom results indicate that PAI has a maximum lateral resolution of 70 µm in resolving structures of targets. DOT was able to recover both optical absorption and reduced scattering coefficients of targets accurately. To validate the potential of this system in clinical diagnosis of joint diseases, the distal interphalangeal (DIP) joints of 4 healthy female volunteers were imaged. We successfully obtained high-resolution images of the phalanx and the surrounding soft tissue via PAI, and recovered both optical absorption and reduced scattering coefficients of phalanx using DOT. The in vivo results suggest that this dual-modality system has the potential for the early diagnosis of joint diseases such as osteoarthritis (OA) and rheumatoid arthritis (RA). Integrated PAI/DOT imaging interface (top) and typical reconstruction of structures and associated optical properties of a female finger joint via PAI and DOT (bottom). PMID:26431473

  5. High resolution three-dimensional photoacoustic imaging of human finger joints in vivo

    NASA Astrophysics Data System (ADS)

    Xi, Lei; Jiang, Huabei

    2015-08-01

    We present a method for noninvasively imaging the hand joints using a three-dimensional (3D) photoacoustic imaging (PAI) system. This 3D PAI system utilizes cylindrical scanning in data collection and virtual-detector concept in image reconstruction. The maximum lateral and axial resolutions of the PAI system are 70 μm and 240 μm. The cross-sectional photoacoustic images of a healthy joint clearly exhibited major internal structures including phalanx and tendons, which are not available from the current photoacoustic imaging methods. The in vivo PAI results obtained are comparable with the corresponding 3.0 T MRI images of the finger joint. This study suggests that the proposed method has the potential to be used in early detection of joint diseases such as osteoarthritis.

  6. Multipixel system for gigahertz frequency-domain optical imaging of finger joints

    NASA Astrophysics Data System (ADS)

    Netz, Uwe J.; Beuthan, Jürgen; Hielscher, Andreas H.

    2008-03-01

    Frequency-domain optical imaging systems have shown great promise for characterizing blood oxygenation, hemodynamics, and other physiological parameters in human and animal tissues. However, most of the frequency domain systems presented so far operate with source modulation frequencies below 150MHz. At these low frequencies, their ability to provide accurate data for small tissue geometries such as encountered in imaging of finger joints or rodents is limited. Here, we present a new system that can provide data up to 1GHz using an intensity modulated charged coupled device camera. After data processing, the images show the two-dimensional distribution of amplitude and phase of the light modulation on the finger surface. The system performance was investigated and test measurements on optical tissue phantoms were taken to investigate whether higher frequencies yield better signal-to-noise ratios (SNRs). It could be shown that local changes in optical tissue properties, as they appear in the initial stages of rheumatoid arthritis in a finger joint, are detectable by simple image evaluation, with the range of modulation frequency around 500MHz proving to yield the highest SNR.

  7. Applied Joint-Space Torque and Stiffness Control of Tendon-Driven Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Wampler, Charles W.; Hargrave, Brian

    2010-01-01

    Existing tendon-driven fingers have applied force control through independent tension controllers on each tendon, i.e. in the tendon-space. The coupled kinematics of the tendons, however, cause such controllers to exhibit a transient coupling in their response. This problem can be resolved by alternatively framing the controllers in the joint-space of the manipulator. This work presents a joint-space torque control law that demonstrates both a decoupled and significantly faster response than an equivalent tendon-space formulation. The law also demonstrates greater speed and robustness than comparable PI controllers. In addition, a tension distribution algorithm is presented here to allocate forces from the joints to the tendons. It allocates the tensions so that they satisfy both an upper and lower bound, and it does so without requiring linear programming or open-ended iterations. The control law and tension distribution algorithm are implemented on the robotic hand of Robonaut-2.

  8. [The development of a finger joint phantom for the optical simulation of early inflammatory rheumatic changes].

    PubMed

    Prapavat, V; Runge, W; Mans, J; Krause, A; Beuthan, J; Müller, G

    1997-11-01

    In the field of rheumatology, conventional diagnostic methods permit the detection only of advanced stages of the disease, which is at odds with the current clinical demand for the early diagnosis of inflammatory rheumatic diseases. Prompted by current needs, we developed a finger joint phantom that enables the optical and geometrical simulation of an early stage of rheumatoid arthritis (RA). The results presented here form the experimental basis for an evaluation of new RA diagnostic systems based on near infrared light. The early stage of RA is characterised mainly by a vigorous proliferation of the synovial membrane and clouding of the synovial fluid. Using a double-integrating-sphere technique, the absorption and scattering coefficients (mua, mus') are experimentally determined for healthy and pathologically altered synovial fluid and capsule tissue. Using a variable mixture of Intralipid Indian ink and water as a scattering/absorption medium, the optical properties of skin, synovial fluid or capsule can be selected individually. Since the optical and geometrical properties of bone tissue remain constant in early-stage RA, a solid material is used for its simulation. Using the finger joint phantom described herein, the optical properties of joint regions can be adjusted specifically, enabling an evaluation of their effects on an optical signal--for example, during fluorography--and the investigation of these effects for diagnostically useful information. The experimental foundation for the development of a new optical system for the early diagnosis of RA has now been laid. PMID:9490122

  9. High-Resolution Interleaved Water-Fat MR Imaging of Finger Joints with Chemical-Shift Elimination

    PubMed Central

    You, Zhigang; Seo, Gwysuk; Lerner, Amy; Totterman, Saara; Ritchlin, Christopher; Monu, Johnny

    2015-01-01

    Purpose To study the use of an interleaved water-fat (IWF) sequence with a custom-made RF coil for high-resolution imaging of arthritic finger joints. Materials and Methods High-resolution finger MRI was performed using a custom-made dedicated RF receiver coil and an IWF sequence. A phantom, a cadaver finger specimen and the fingers of two normal controls and six arthritic subjects were imaged with a resolution of 156×156×600 microns. The appearance of anatomic structures on the IWF images were compared with images acquired with a regular sequence. The images were reviewed by two musculoskeletal radiologists for the depiction of anatomical structures and for the presence of abnormalities. Results The high-resolution images revealed detailed structures of the finger joints not detectable using typical clinical resolution. The IWF sequence gave more realistic depiction of subchondral bone thickness, and avoided false bone erosions displayed in the regular sequence. It also allowed better visualization of ligaments and tendons. Conclusion This pilot study shows the feasibility and the potential usefulness of high-resolution IWF imaging for finger joint evaluation. This technique may be useful for the diagnosis and treatment assessment of arthritis, and for the study of joint disease pathogenesis. PMID:21182147

  10. IMU-Based Joint Angle Measurement for Gait Analysis

    PubMed Central

    Seel, Thomas; Raisch, Jorg; Schauer, Thomas

    2014-01-01

    This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1) joint axis and position identification; and (2) flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU)-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°. PMID:24743160

  11. Revisiting the Force-Joint Angle Relationship After Eccentric Exercise.

    PubMed

    Welsh, Molly C; Allen, David L; Batliner, Matthew E; Byrnes, William C

    2015-12-01

    The purpose of this study was to evaluate force-angle curve fitting techniques pre-eccentric exercise, quantify changes in curve characteristics postexercise, and examine the relationship between curve changes and markers of muscle damage. Fourteen males unaccustomed to eccentric exercise performed 60 eccentric muscle actions of the elbow flexors. Maximal voluntary isometric force was measured throughout a range of angles pre- (Pre1 and Pre2), immediately post (IP), and 1, 2, 4, and 7 days postexercise. Force-angle curves for each visit were constructed using second-order polynomials. Changes in curve characteristics (optimal angle, peak force, curve height), range of motion, soreness, and creatine kinase activity were quantified. Optimal joint angle and force at optimal angle were significantly correlated from Pre1 to Pre2 (ICC = 0.821 and 0.979, respectively). Optimal angle was significantly right shifted (p = 0.035) by 10.4 ± 12.9° from Pre2 to IP and was restored by 1 day post exercise. Interestingly, the r value for curve fit was significantly decreased (p < 0.001) from Pre2 (r = 0.896) to IP (r = 0.802) and 1 day post exercise (r = 0.750). Curve height was significantly decreased (39%) IP and restored to pre-exercise height by 4 days postexercise. There was no correlation between optimal angle or curve height and other damage markers. In conclusion, force-angle relationships can be accurately described using second-order polynomials. After eccentric exercise, the force-angle curve is flattened and shifted (downward and rightward), but these changes are not correlated to other markers of muscle damage. Changes in the force-angle relationship are multifaceted, but determining the physiological significance of these changes requires further investigation. PMID:25970492

  12. Effect of fence height on joint angles of agility dogs.

    PubMed

    Birch, Emily; Leśniak, Kirsty

    2013-12-01

    The Kennel Club (KC) and United Kingdom Agility (UKA) govern major dog agility competitions in the UK. Dogs are categorised into different jump heights depending on their height at the withers, with fence heights ranging from 300 to 650 mm for both organisations. Dogs fall into one of three height categories when competing under KC rules and one of four height categories under UKA rules. The aim of this study was to investigate the influence of an additional height category for agility dogs measuring over 430 mm at the withers. Jump heights were selected that related to the percentage of body height that dogs of 430 mm (7% lower) and 431 mm (51% higher) height at the withers would be encouraged to jump under UKA regulations without the addition of their fourth ('standard height') category. Joint angles were determined from anatomical markers placed on the forelimb and hind limb joints, and at six points along the vertebral column. As fence height increased, flexion of the scapulohumeral joint increased significantly for both the take-off and bascule (arc) phases of the jump. The increase in flexion as a consequence of the increase in fence height is likely to result in intensified stretching of the biceps brachii and supraspinatus muscles. In addition, increasing fence high resulted in an increase in the sacroiliac joint angle during take-off. PMID:24360736

  13. Two- and three-dimensional optical tomography of finger joints for diagnostics of rheumatoid arthritis

    NASA Astrophysics Data System (ADS)

    Klose, Alexander D.; Hielscher, Andreas H.; Hanson, Kenneth M.; Beuthan, Juergen

    1998-12-01

    Rheumatoid arthritis (RA) is one of the most common diseases of human joints. This progressive disease is characterized by an inflammation process that originates in the inner membrane (synovalis) of the capsule and spreads to other parts of the joint. In early stages the synovalis thickness and the permeability of this membrane changes. This leads to changes in the optical parameters of the synovalis and the synovial fluid (synovia), which occupies the space between the bones. The synovia changes from a clear yellowish fluid to a turbid grayish substance. In this work we present 2 and 3-dimensional reconstruction schemes for optical tomography of the finger joints. Our reconstruction algorithm is based on the diffusion approximation and employs adjoint differentiation techniques for the gradient calculation of the objective function with respect to the spatial distribution of optical properties. In this way, the spatial distribution of optical properties within the joints is reconstructed with high efficiency and precision. Volume information concerning the synovial space and the capsula are provided. Furthermore, it is shown that small changes of the scattering coefficients can be monitored. Therefore, optical tomography has the potential of becoming a useful tool for the early diagnosis and monitoring of disease progression in RA.

  14. Joint angle estimation with accelerometers for dynamic postural analysis.

    PubMed

    Ma, Jianting; Kharboutly, Haissam; Benali, Abderraouf; Benamar, Faïz; Bouzit, Mourad

    2015-10-15

    This paper presents a new accelerometer based method for estimating the posture of a subject standing on a dynamic perturbation platform. The induced perturbation is used to study the control mechanisms as well as the balance requirements that regulate the upright standing. These perturbations are translated into different intensity levels of speed and acceleration along longitudinal and lateral directions of motion. In our method, the human posture is modeled by a tridimensional, three-segment inverted pendulum which simultaneously takes into account both the anterior-posterior and medio-lateral strategies of hip and ankle. Four tri-axial accelerometers are used her, one accelerometer is placed on the platform, and the other three are attached to a human subject. Based on the results, the joint angle estimated compare closely to measurements from magnetic encoders placed on an articulated arm joint. The results were also comparable to those found when using a high-end optical motion capture system coupled with advanced biomechanical simulation software. This paper presents the comparisons of our accelerometer-based method with encoder and optical marker based method of the estimated joint angles under different dynamics perturbations. PMID:26338097

  15. Classification of optical tomographic images of rheumatoid finger joints with support vector machines

    NASA Astrophysics Data System (ADS)

    Balasubramanyam, Vivek; Hielscher, Andreas H.

    2005-04-01

    Over the last years we have developed a sagittal laser optical tomographic (SLOT) imaging system for the diagnosis and monitoring of inflammatory processes in proximal interphalangeal (PIP) joint of patients with rheumatoid arthritis (RA). While cross sectional images of the distribution of optical properties can now be generated easily, clinical interpretation of these images remains a challenge. In first clinical studies involving 78 finger joints, we compared optical tomographs to ultrasound images and clinical analyses. Receiver-operator curves (ROC) were generated using various image parameters, such as minimum and maximum scattering or absorption coefficients. These studies resulted in specificities and sensitivities in the range of 0.7 to 0.76. Recently, we have trained support vector machines (SVMs) to classify images of healthy and diseased joints. By eliminating redundancy using feature selection, we are achieving sensitivities of 0.72 and specificities up to 1.0. Studies with larger patient groups are necessary to validate these findings; but these initial results support the expectation that SVMs and other machine learning techniques can considerably improve image interpretation analysis in optical tomography.

  16. Tumoral pseudogout of the proximal interphalangeal joint of a finger: a case report and literature review.

    PubMed

    Park, Hyo Jung; Chung, Hye Won; Oh, Tack Sun; Lee, Jong-Seok; Song, Joon Seon; Park, Yong-Koo

    2016-07-01

    Tumoral pseudogout is a rare clinical form of calcium pyrophosphate dihydrate crystal deposition disease. Tumoral pseudogout can mimic other diseases such as chondroid tumor, tophaceous gout, or tumoral calcinosis. Its radiological features have been presented in some case reports, but no specific radiographic features have been identified. Here, we report an unusual case of recurrent tumoral pseudogout involving the proximal interphalangeal joint of the right long finger. This case presents with progressive radiological findings of the disease with an enlarging and recurrent calcified mass and secondary bony erosion and remodeling, along with a radiological-pathological correlation. We also review previously reported imaging findings of this disease entity, differential points in comparison to other diseases, and some key points for making the correct diagnosis. PMID:27048476

  17. Static torque-angle relation of human elbow joint estimated with artificial neural network technique.

    PubMed

    Uchiyama, T; Bessho, T; Akazawa, K

    1998-06-01

    Static relations between elbow joint angle and torque at constant muscle activity in normal volunteers were investigated with the aid of an artificial neural network technique. A subject sat on a chair and moved his upper- and forearm in a horizontal plane at the height of his shoulder. The subject was instructed to maintain the elbow joint at a pre-determined angle. The wrist was then pulled to extend the elbow joint by the gravitational force of a weight hanging from a pulley. Integrated electromyograms (IEMGs), elbow and shoulder joint angles and elbow joint torque were measured. Then the relation among IEMGs, joint angles and torque was modeled with the aid of the artificial neural network, where IEMGs and joint angles were the inputs and torque was the output. After back propagation learning, we presented various combinations of IEMGs, shoulder and elbow joint angles to the model and estimated the elbow joint torque to obtain the torque-angle relation for constant muscle activation. The elbow joint torque increased and then decreased with extension of the elbow joint. This suggests that if the forearm is displaced from an equilibrium point, the torque angle relation would not act like a simple spring. In a view of the musculoskeletal structure of the elbow joint, the relation between the elbow joint angle and the moment arm of the elbow flexor muscles seems to have a dominant effect on the torque-angle relation. PMID:9755039

  18. A multifunctional joint angle sensor with measurement adaptability.

    PubMed

    Quan, Wei; Wang, Hua; Liu, Datong

    2013-01-01

    The paper presents a multifunctional joint sensor with measurement adaptability for biological engineering applications, such as gait analysis, gesture recognition, etc. The adaptability is embodied in both static and dynamic environment measurements, both of body pose and in motion capture. Its multifunctional capabilities lay in its ability of simultaneous measurement of multiple degrees of freedom (MDOF) with a single sensor to reduce system complexity. The basic working mode enables 2DOF spatial angle measurement over big ranges and stands out for its applications on different joints of different individuals without recalibration. The optional advanced working mode enables an additional DOF measurement for various applications. By employing corrugated tube as the main body, the sensor is also characterized as flexible and wearable with less restraints. MDOF variations are converted to linear displacements of the sensing elements. The simple reconstruction algorithm and small outputs volume are capable of providing real-time angles and long-term monitoring. The performance assessment of the built prototype is promising enough to indicate the feasibility of the sensor. PMID:24217353

  19. Tests of wireless wearable sensor system in joint angle measurement of lower limbs.

    PubMed

    Watanabe, Takashi; Saito, Hiroki

    2011-01-01

    The aim of this study was to test the wireless wearable sensor system consists of inertial sensors considering application to rehabilitation. The sensor system was evaluated in measurement of hip, knee and ankle joint angles with healthy subjects comparing to those measured with a 3D motion measurement system. Then, the lower limb joint angles of elderly subjects including paralyzed subjects were measured during gait on the level floor with the sensor system. Evaluation of measured joint angles in comparison with the motion measurement system showed that mean values of the RMSE were smaller than 4 deg for all the joint angles, and mean values of the correlation coefficient were larger than 0.985 for hip and knee joint angles and about 0.90 for ankle joint angle. In measurement with elderly subjects, the sensor system showed some differences in joint angles between the paralyzed and the non-paralyzed sides. PMID:22255575

  20. Successful treatment of a guitarist with a finger joint injury using instrument-assisted soft tissue mobilization: a case report.

    PubMed

    Terry Loghmani, M; Bayliss, Amy J; Clayton, Greg; Gundeck, Evelina

    2015-12-01

    Finger injuries are common and can greatly affect a musician's quality of life. A 55-year-old man, who had injured the proximal interphalangeal joint of the left index finger 6 months prior to any intervention, was treated with a manual therapy approach incorporating instrument-assisted soft tissue mobilization (IASTM). Initial examination findings included self-reported pain and functional limitations and physical impairments that significantly impeded his ability to play the acoustic guitar. He was treated once a week for 6 weeks with IASTM, joint mobilization, therapeutic exercise, and ice massage. Additionally, a home exercise program and self-care instructions were provided. The patient gained positive outcomes with improvements in pain (Numerical Pain Rating Scale while playing the guitar: initial 5/10, discharge 1/10) and function (Disability Arm Shoulder Hand Sports-Performing Arts Optional Module: initial 75; discharge 6·25), each reaching a minimum clinically important difference. Importantly, he was able to play the guitar with minimal to no pain as desired. Physical measures also improved, including an immediate gain in finger range of motion with IASTM alone. Manual therapy approaches integrating IASTM may provide an effective conservative treatment strategy for patients with finger/hand conditions in the performing arts and other patient populations. PMID:26952165

  1. A cortically-inspired model for inverse kinematics computation of a humanoid finger with mechanically coupled joints.

    PubMed

    Gentili, Rodolphe J; Oh, Hyuk; Kregling, Alissa V; Reggia, James A

    2016-06-01

    The human hand's versatility allows for robust and flexible grasping. To obtain such efficiency, many robotic hands include human biomechanical features such as fingers having their two last joints mechanically coupled. Although such coupling enables human-like grasping, controlling the inverse kinematics of such mechanical systems is challenging. Here we propose a cortical model for fine motor control of a humanoid finger, having its two last joints coupled, that learns the inverse kinematics of the effector. This neural model functionally mimics the population vector coding as well as sensorimotor prediction processes of the brain's motor/premotor and parietal regions, respectively. After learning, this neural architecture could both overtly (actual execution) and covertly (mental execution or motor imagery) perform accurate, robust and flexible finger movements while reproducing the main human finger kinematic states. This work contributes to developing neuro-mimetic controllers for dexterous humanoid robotic/prosthetic upper-extremities, and has the potential to promote human-robot interactions. PMID:27194213

  2. Upper limb joint angle measurement in occupational health.

    PubMed

    Álvarez, Diego; Alvarez, Juan C; González, Rafael C; López, Antonio M

    2016-01-01

    Usual human motion capture systems are designed to work in controlled laboratory conditions. For occupational health, instruments that can measure during normal daily life are essential, as the evaluation of the workers' movements is a key factor to reduce employee injury- and illness-related costs. In this paper, we present a method for joint angle measurement, combining inertial sensors (accelerometers and gyroscopes) and magnetic sensors. This method estimates wrist flexion, wrist lateral deviation, elbow flexion, elbow pronation, shoulder flexion, shoulder abduction and shoulder internal rotation. The algorithms avoid numerical integration of the signals, which allows for long-time estimations without angle estimation drift. The system has been tested both under laboratory and field conditions. Controlled laboratory tests show mean estimation errors between 0.06° and of 1.05°, and standard deviation between 2.18° and 9.20°. Field tests seem to confirm these results when no ferromagnetic materials are close to the measurement system. PMID:25573165

  3. Assessing Finger Joint Biomechanics by Applying Equal Force to Flexor Tendons In Vitro Using a Novel Simultaneous Approach

    PubMed Central

    Yang, Tai-Hua; Lu, Szu-Ching; Lin, Wei-Jr; Zhao, Kristin; Zhao, Chunfeng; An, Kai-Nan; Jou, I-Ming; Lee, Pei-Yuan

    2016-01-01

    Background The flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) are critical for finger flexion. Although research has recently focused on these tendons’ coactivity, their contributions in different tasks remain unclear. This study created a novel simultaneous approach to investigate the coactivity between the tendons and to clarify their contributions in different tasks. Methods Ten human cadaveric hands were mounted on our custom frame with the FDS and FDP of the third finger looped through a mechanical pulley connected to a force transducer. Joint range of motion, tendon excursion and loading force were recorded during individual joint motion and free joint movement from rest to maximal flexion. Each flexor tendon’s moment arm was then calculated. Results In individual motions, we found that the FDP contributed more than the FDS in proximal interphalangeal (PIP) joint motion, with an overall slope of 1.34 and all FDP-to-FDS excursion (P/S) ratios greater than 1.0 with force increase. However, the FDP contributed less than the FDS in metacarpophalangeal (MCP) joint motion, with an overall slope of 0.95 and P/S ratios smaller than 1.0 throughout the whole motion except between 1.9% and 13.1% force. In free joint movement, the FDP played a greater role than the FDS, with an overall ratio of 1.37 and all P/S ratios greater than 1.0. Conclusions The new findings include differences in finger performance and excursion amounts between the FDS and FDP throughout flexion. Such findings may provide the basis for new hand models and treatments. PMID:27513744

  4. Optimal design of a six-bar linkage with one degree of freedom for an anthropomorphic three-jointed finger mechanism.

    PubMed

    Guo, G; Zhang, J; Gruver, W A

    1993-01-01

    This research concerns the design of a three-jointed, anthropomorphic, finger mechanism for use as a prosthesis or robotic end-effector. Based on a study of finger configurations for the human hand, a six-bar linkage with one degree of freedom is proposed. A model of the fingertip displacement of the mechanism is derived by a vector analysis approach. The effects of joint friction on the transmission efficiency are analysed. By measuring the joint positions of a human finger, a mathematical model of the pinching and holding configurations are developed. Optimal parameters for the finger mechanism are obtained by non-linear programming based on an objective functional involving motion posture and locus, transmission efficiency and weight subject to geometric and bionic constraints. Simulation results indicate that the mechanism is useful for a variety of prosthetic and robotic applications. PMID:8117370

  5. Morbid anatomy of ‘erosive osteoarthritis’ of the interphalangeal finger joints: an optimised scoring system to monitor disease progression in affected joints

    PubMed Central

    Verbruggen, Gust; Wittoek, Ruth; Cruyssen, Bert Vander; Elewaut, Dirk

    2010-01-01

    Objectives To develop and validate a quantitative radiographic scoring system, the Ghent University Scoring System (GUSS), with better ability to detect progression over a shorter period of time in erosive osteoarthritis (OA) of the interphalangeal (IP) finger joints compared with the existing anatomic phase scoring system. Methods Thirty IP finger joints showing erosive features at baseline or follow-up were selected from 18 patients with erosive hand OA. Posteroanterior radiographs of these joints obtained at baseline, 6 and 12 months—totalling 90 images—were used for the study. All joints were first scored according to the original anatomic phase scoring system. Erosive progression and signs of repair or remodelling were then scored by indicating the proportion of normal subchondral bone, subchondral plate and joint space on an 11-point rating scale (range 0–100 with 10 unit increases). Inter- and intrareader reproducibility was studied using intraclass correlation coefficients (ICCs). Based on the within-variance of two readers, the smallest detectable change (SDC) was calculated and allowed identification of joints with changes above the SDC as ‘progressors’. Results Longitudinal inter-reader ICC scores rated well for all variables and the total score (ICC 0.86–0.93). To identify ‘real’ change over background noise, a change of at least 40 units on the total score (range 0–300) over 12 months (SDC 0–12:36.0), and 50 units over 6 months (SDC 0–6:47.6) had to be present. 60% of the 30 joints were identified as ‘progressors’ over 6 months compared with 33.3% with the classical anatomical scoring system, and 70% versus 56.6%, respectively, over 12 months. Conclusion GUSS, is a reliable method to score radiographic change over time in erosive IP OA and detects more progression over a shorter period of time than the classical scoring system. PMID:19948521

  6. Accuracy Improvement on the Measurement of Human-Joint Angles.

    PubMed

    Meng, Dai; Shoepe, Todd; Vejarano, Gustavo

    2016-03-01

    A measurement technique that decreases the root mean square error (RMSE) of measurements of human-joint angles using a personal wireless sensor network is reported. Its operation is based on virtual rotations of wireless sensors worn by the user, and it focuses on the arm, whose position is measured on 5 degree of freedom (DOF). The wireless sensors use inertial magnetic units that measure the alignment of the arm with the earth's gravity and magnetic fields. Due to the biomechanical properties of human tissue (e.g., skin's elasticity), the sensors' orientation is shifted, and this shift affects the accuracy of measurements. In the proposed technique, the change of orientation is first modeled from linear regressions of data collected from 15 participants at different arm positions. Then, out of eight body indices measured with dual-energy X-ray absorptiometry, the percentage of body fat is found to have the greatest correlation with the rate of change in sensors' orientation. This finding enables us to estimate the change in sensors' orientation from the user's body fat percentage. Finally, an algorithm virtually rotates the sensors using quaternion theory with the objective of reducing the error. The proposed technique is validated with experiments on five different participants. In the DOF, whose error decreased the most, the RMSE decreased from 2.20(°) to 0.87(°). This is an improvement of 60%, and in the DOF whose error decreased the least, the RMSE decreased from 1.64(°) to 1.37(°). This is an improvement of 16%. On an average, the RMSE improved by 44%. PMID:25622331

  7. Goniometrie evaluation of standing extension and maximum flexion joint angles of llamas and alpacas.

    PubMed

    Walters, Amy L; Semevolos, Stacy A; Baker, Rose E

    2016-09-01

    OBJECTIVE To determine and compare mean standing extension and maximum flexion angles of various joints in healthy adult alpacas and llamas, and determine the reliability of goniometric data within and between 2 observers for each joint of interest. SAMPLE 6 healthy adult llamas and 6 healthy adult alpacas. PROCEDURES The shoulder joint, elbow joint, carpal, and metacarpophalangeal (MCP) joints of the forelimbs and the hip joint, stifle joint, tarsal, and metatarsophalangeal (MTP) joints of the hind limbs were investigated. Each articulation was measured with a universal goniometer by 2 observers, who each obtained 2 measurements when each joint was maintained in standing extension and in maximal passive flexion. Two sample (unpaired) t tests were performed for comparisons of mean standing extension and maximum passive flexion angles between alpacas and llamas. Intraclass correlation coefficients were calculated for each articulation to assess interobserver and intra-observer reliability of measurements. RESULTS Llamas had larger mean standing extension angles than alpacas for the tarsal and elbow joint, but there were no significant differences between species for all other joints. For all joints, flexion measurements did not differ significantly between the 2 species. For most joints, the reliability of goniometric data between observers was good to excellent (intraclass correlation coefficients, 0.6 to 0.95) CONCLUSIONS AND CLINICAL RELEVANCE Except for the elbow joint and tarsus in extension, the angle of limb articulations during flexion and extension can be considered similar for alpacas and llamas. These measurements have relevance for veterinary surgeons when assessing joint mobility and conformation and determining appropriate angles for arthrodesis. PMID:27580112

  8. 98. 28'X40' original vellum, VariableAngle Launcher '32 INCH 'Y' JOINT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    98. 28'X40' original vellum, Variable-Angle Launcher '32 INCH 'Y' JOINT AND TRANSITION ASSEMBLY' drawn at 1 1/2'=1'-0'. (P.W. DWG. NO. 1785). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  9. 99. 28'X40' original vellum, VariableAngle Launcher '32 INCH 'Y' JOINT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    99. 28'X40' original vellum, Variable-Angle Launcher '32 INCH 'Y' JOINT DETAILS drawn at 1 1/2'=1'-0' and 6'=1'-0'. (P.W. DWG. NO. 1786). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  10. An Architecture for Measuring Joint Angles Using a Long Period Fiber Grating-Based Sensor

    PubMed Central

    Perez-Ramirez, Carlos A.; Almanza-Ojeda, Dora L.; Guerrero-Tavares, Jesus N.; Mendoza-Galindo, Francisco J.; Estudillo-Ayala, Julian M.; Ibarra-Manzano, Mario A.

    2014-01-01

    The implementation of signal filters in a real-time form requires a tradeoff between computation resources and the system performance. Therefore, taking advantage of low lag response and the reduced consumption of resources, in this article, the Recursive Least Square (RLS) algorithm is used to filter a signal acquired from a fiber-optics-based sensor. In particular, a Long-Period Fiber Grating (LPFG) sensor is used to measure the bending movement of a finger. After that, the Gaussian Mixture Model (GMM) technique allows us to classify the corresponding finger position along the motion range. For these measures to help in the development of an autonomous robotic hand, the proposed technique can be straightforwardly implemented on real time platforms such as Field Programmable Gate Array (FPGA) or Digital Signal Processors (DSP). Different angle measurements of the finger's motion are carried out by the prototype and a detailed analysis of the system performance is presented. PMID:25536002

  11. An architecture for measuring joint angles using a long period fiber grating-based sensor.

    PubMed

    Perez-Ramirez, Carlos A; Almanza-Ojeda, Dora L; Guerrero-Tavares, Jesus N; Mendoza-Galindo, Francisco J; Estudillo-Ayala, Julian M; Ibarra-Manzano, Mario A

    2014-01-01

    The implementation of signal filters in a real-time form requires a tradeoff between computation resources and the system performance. Therefore, taking advantage of low lag response and the reduced consumption of resources, in this article, the Recursive Least Square (RLS) algorithm is used to filter a signal acquired from a fiber-optics-based sensor. In particular, a Long-Period Fiber Grating (LPFG) sensor is used to measure the bending movement of a finger. After that, the Gaussian Mixture Model (GMM) technique allows us to classify the corresponding finger position along the motion range. For these measures to help in the development of an autonomous robotic hand, the proposed technique can be straightforwardly implemented on real time platforms such as Field Programmable Gate Array (FPGA) or Digital Signal Processors (DSP). Different angle measurements of the finger's motion are carried out by the prototype and a detailed analysis of the system performance is presented. PMID:25536002

  12. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  13. The Effects of Sex, Joint Angle, and the Gastrocnemius Muscle on Passive Ankle Joint Complex Stiffness

    PubMed Central

    DeMont, Richard G.; Ryu, Keeho; Lephart, Scott M.

    2001-01-01

    Objective: To assess the effects of sex, joint angle, and the gastrocnemius muscle on passive ankle joint complex stiffness (JCS). Design and Setting: A repeated-measures design was employed using sex as a between-subjects factor and joint angle and inclusion of the gastrocnemius muscle as within-subject factors. All testing was conducted in a neuromuscular research laboratory. Subjects: Twelve female and 12 male healthy, physically active subjects between the ages of 18 and 30 years volunteered for participation in this study. The dominant leg was used for testing. No subjects had a history of lower extremity musculoskeletal injury or circulatory or neurologic disorders. Measurements: We determined passive ankle JCS by measuring resistance to passive dorsiflexion (5°·s−1) from 23° plantar flexion (PF) to 13° dorsiflexion (DF). Angular position and torque data were collected from a dynamometer under 2 conditions designed to include or reduce the contribution of the gastrocnemius muscle. Separate fourth-order polynomial equations relating angular position and torque were constructed for each trial. Stiffness values (Nm·degree−1) were calculated at 10° PF, neutral (NE), and 10° DF using the slope of the line at each respective position. Results: Significant condition-by-position and sex-by-position interactions and significant main effects for sex, position, and condition were revealed by a 3-way (sex-by-position, condition-by-position) analysis of variance. Post hoc analyses of the condition-by-position interaction revealed significantly higher stiffness values under the knee-straight condition compared with the knee-bent condition at both ankle NE and 10° DF. Within each condition, stiffness values at each position were significantly higher as the ankle moved into DF. Post hoc analysis of the sex-by-position interaction revealed significantly higher stiffness values at 10° DF in the male subjects. Post hoc analysis of the position main effect revealed

  14. Noninvasive imaging of hemoglobin concentration and oxygen saturation for detection of osteoarthritis in the finger joints using multispectral three-dimensional quantitative photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Sun, Yao; Sobel, Eric; Jiang, Huabei

    2013-05-01

    We present quantitative imaging of hemoglobin concentration and oxygen saturation in in vivo finger joints and evaluate the feasibility of detecting osteoarthritis (OA) in the hand using three-dimensional (3D) multispectral quantitative photoacoustic tomography (3D qPAT). The results show that both the anatomical structures and quantitative chromophore concentrations (oxy-hemoglobin and deoxy-hemoglobin) of different joint tissues (hard phalanges and soft cartilage/synovial fluid between phalanges) can be imaged in vivo with the multispectral 3D qPAT. Enhanced hemoglobin concentrations and dropped oxygen saturations in osteoarthritic phalanges and soft joint tissues in joint cavities have been observed. This study indicates that the multispectral 3D qPAT is a promising approach to detect the angiogenesis and hypoxia associated with OA disease and a potential clinical tool for early OA detection in the finger joints.

  15. A three-dimensional finite element analysis of finger joint stresses in the MCP joint while performing common tasks.

    PubMed

    Butz, Kent D; Merrell, Greg; Nauman, Eric A

    2012-09-01

    The goal of this study was to develop a three-dimensional finite element model of the metacarpophalangeal (MCP) joint to characterize joint contact stresses incurred during common daily activities. The metacarpal and proximal phalanx were modeled using a COMSOL-based finite element analysis. Muscle forces determined from a static force analysis of two common activities (pen grip and carrying a weight) were applied to the simulation to characterize the surface stress distributions at the MCP joint. The finite element analysis predicted that stresses as high as 1.9 MPa, similar in magnitude to stresses experienced at the hip, may be experienced by the subchondral bone in the MCP joint. The internal structure and material properties of the phalanges were found to play a significant role in both the magnitude and distribution of stresses, but the dependence on cancellous bone modulus was not as severe as predicted by previous two dimensional models. PMID:23997746

  16. Mallet finger injuries-A new method to maintain distal interphalangeal joint extension.

    PubMed

    Mak, Lonita; Aitkens, Lorna D; Novak, Christine B

    2016-01-01

    Ensuring that distal interphalangeal joint extension is maintained is an important but challenging part of the treatment process. These authors describe a simple approach to ensuring distal interphalangeal joint extension for these patients. - VictoriaPriganc, PhD, OTR, CHT, CLT, Practice Forum Editor. PMID:27496991

  17. Quantitative three-dimensional photoacoustic tomography of the finger joints: an in vivo study

    NASA Astrophysics Data System (ADS)

    Sun, Yao; Sobel, Eric; Jiang, Huabei

    2009-11-01

    We present for the first time in vivo full three-dimensional (3-D) photoacoustic tomography (PAT) of the distal interphalangeal joint in a human subject. Both absorbed energy density and absorption coefficient images of the joint are quantitatively obtained using our finite-element-based photoacoustic image reconstruction algorithm coupled with the photon diffusion equation. The results show that major anatomical features in the joint along with the side arteries can be imaged with a 1-MHz transducer in a spherical scanning geometry. In addition, the cartilages associated with the joint can be quantitatively differentiated from the phalanx. This in vivo study suggests that the 3-D PAT method described has the potential to be used for early diagnosis of joint diseases such as osteoarthritis and rheumatoid arthritis.

  18. Joint-Angle Coordination Patterns Ensure Stabilization of a Body-Plus-Tool System in Point-to-Point Movements with a Rod

    PubMed Central

    Valk, Tim A.; Mouton, Leonora J.; Bongers, Raoul M.

    2016-01-01

    When performing a goal-directed action with a tool, it is generally assumed that the point of control of the action system is displaced from the hand to the tool, implying that body and tool function as one system. Studies of how actions with tools are performed have been limited to studying either end-effector kinematics or joint-angle coordination patterns. Because joint-angle coordination patterns affect end-effector kinematics, the current study examined them together, with the aim of revealing how body and tool function as one system. Seated participants made point-to-point movements with their index finger, and with rods of 10, 20, and 30 cm attached to their index finger. Start point and target were presented on a table in front of them, and in half of the conditions a participant displacement compensated for rod length. Results revealed that the kinematics of the rod's tip showed higher peak velocity, longer deceleration time, and more curvature with longer rods. End-effector movements were more curved in the horizontal plane when participants were not displaced. Joint-angle trajectories were similar across rod lengths when participants were displaced, whereas more extreme joint-angles were used with longer rods when participants were not displaced. Furthermore, in every condition the end-effector was stabilized to a similar extent; both variability in joint-angle coordination patterns that affected end-effector position and variability that did not affect end-effector position increased in a similar way vis-à-vis rod length. Moreover, the increase was higher in those conditions, in which participants were not displaced. This suggests that during tool use, body and tool are united in a single system so as to stabilize the end-effector kinematics in a similar way that is independent of tool length. In addition, the properties of the actual trajectory of the end-effector, as well as the actual joint-angles used, depend on the length of the tool and the

  19. Extrinsic versus intrinsic hand muscle dominance in finger flexion.

    PubMed

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

    2016-05-01

    This study aims to identify the patterns of dominance of extrinsic or intrinsic muscles in finger flexion during initiation of finger curl and mid-finger flexion. We recorded 82 hands of healthy individuals (18-74 years) while flexing their fingers and tracked the finger joint angles of the little finger using video motion tracking. A total of 57 hands (69.5%) were classified as extrinsic dominant, where the finger flexion was initiated and maintained at proximal interphalangeal and distal interphalangeal joints. A total of 25 (30.5%) were classified as intrinsic dominant, where the finger flexion was initiated and maintained at the metacarpophalangeal joint. The distribution of age, sex, dominance, handedness and body mass index was similar in the two groups. This knowledge may allow clinicians to develop more efficient rehabilitation regimes, since intrinsic dominant individuals would not initiate extrinsic muscle contraction till later in finger flexion, and might therefore be allowed limited early active motion. For extrinsic dominant individuals, by contrast, initial contraction of extrinsic muscles would place increased stress on the tendon repair site if early motion were permitted. PMID:26744509

  20. Hip rotation angle is associated with frontal plane knee joint mechanics during running.

    PubMed

    Sakaguchi, Masanori; Shimizu, Norifumi; Yanai, Toshimasa; Stefanyshyn, Darren J; Kawakami, Yasuo

    2015-02-01

    Inability to control lower extremity segments in the frontal and transverse planes resulting in large knee abduction angle and increased internal knee abduction impulse has been associated with patellofemoral pain (PFP). However, the influence of hip rotation angles on frontal plane knee joint kinematics and kinetics remains unclear. The purpose of this study was to explore how hip rotation angles are related to frontal plane knee joint kinematics and kinetics during running. Seventy runners participated in this study. Three-dimensional marker positions and ground reaction forces were recorded with an 8-camera motion analysis system and a force plate while subjects ran along a 25-m runway at a speed of 4m/s. Knee abduction, hip rotation and toe-out angles, frontal plane lever arm at the knee, internal knee abduction moment and impulse, ground reaction forces and the medio-lateral distance from the ankle joint center to the center of pressure (AJC-CoP) were quantified. The findings of this study indicate that greater hip external rotation angles were associated with greater toe-out angles, longer AJC-CoP distances, smaller internal knee abduction impulses with shorter frontal plane lever arms and greater knee abduction angles. Thus, there appears to exist a conflict between kinematic and kinetic risk factors of PFP, and hip external rotation angle may be a key factor to control frontal plane knee joint kinematics and kinetics. These results may help provide an appropriate manipulation and/or intervention on running style to reduce the risk of PFP. PMID:25572723

  1. Three-Fingered Robot Hand

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.; Salisbury, J. K.

    1984-01-01

    Mechanical joints and tendons resemble human hand. Robot hand has three "human-like" fingers. "Thumb" at top. Rounded tips of fingers covered with resilient material provides high friction for griping. Hand potential as prosthesis for humans.

  2. Feasibility study of semi-automated measurements of finger joint space widths.

    PubMed

    Pfeil, Alexander; Sommerfeld, Julia; Fröber, Rosemarie; Lehmann, Gabriele; Malich, Ansgar; Hansch, Andreas; Wolf, Gunter; Böttcher, Joachim

    2011-10-01

    The purpose of this study is to evaluate technical feasibility based on image capturing conditions (film-focus distance (FFD), film sensitivity, film brand, exposure level and tube voltage) that potentially alter radiographs and consequently may influence the semi-automated measurement of joint space distance (JSD) by computer-aided joint space analysis (CAJSA) in rheumatoid arthritis and osteoarthritis. The radiographs of a left hand (deceased man) were acquired under systematically changing image capturing conditions (exposure level: 4-8 mAs; FFD: 90-130 cm; film sensitivity: 200/400 and tube voltage: 40-52 kV with different image modalities: conventional radiographs, original digital radiographs, digital print-outs). All JSD-measurements were performed with the CAJSA-technology (Radiogrammetry Kit, Version 1.3.6; Sectra; Sweden) at the metacarpal-phalangeal articulation. JSD-analysis was not influenced by changes of FFD, exposure level, film sensitivity or film brand. JSD showed significant variation caused by tube voltage (conventional: CV = 1.913% for Agfa and CV = 2.448% for Kodak; digital: CV = 0.741% for Philips print-outs and CV = 0.620% with original digital images versus CV = 2.185% for Siemens print-outs and 0.951% with original digital images). Computer-aided joint space analysis for JSD-measurements is unaffected by the following image capturing parameters: film-focus distance, film sensitivity, film brand and exposure level. An influence of tube voltage was detected in a lesser extent for original digital images compared to the printed digital as well as conventional versions. Consequently, a standardized tube voltage is essential for accurate reproductions of CAJSA-measurements in rheumatoid arthritis and osteoarthritis. PMID:20401484

  3. Multi-fingered robotic hand

    NASA Technical Reports Server (NTRS)

    Ruoff, Carl F. (Inventor); Salisbury, Kenneth, Jr. (Inventor)

    1990-01-01

    A robotic hand is presented having a plurality of fingers, each having a plurality of joints pivotally connected one to the other. Actuators are connected at one end to an actuating and control mechanism mounted remotely from the hand and at the other end to the joints of the fingers for manipulating the fingers and passing externally of the robot manipulating arm in between the hand and the actuating and control mechanism. The fingers include pulleys to route the actuators within the fingers. Cable tension sensing structure mounted on a portion of the hand are disclosed, as is covering of the tip of each finger with a resilient and pliable friction enhancing surface.

  4. Lower Extremity Joint Angle Tracking with Wireless Ultrasonic Sensors during a Squat Exercise

    PubMed Central

    Qi, Yongbin; Soh, Cheong Boon; Gunawan, Erry; Low, Kay-Soon; Thomas, Rijil

    2015-01-01

    This paper presents an unrestrained measurement system based on a wearable wireless ultrasonic sensor network to track the lower extremity joint and trunk kinematics during a squat exercise with only one ultrasonic sensor attached to the trunk. The system consists of an ultrasound transmitter (mobile) and multiple receivers (anchors) whose positions are known. The proposed system measures the horizontal and vertical displacement, together with known joint constraints, to estimate joint flexion/extension angles using an inverse kinematic model based on the damped least-squares technique. The performance of the proposed ultrasonic measurement system was validated against a camera-based tracking system on eight healthy subjects performing a planar squat exercise. Joint angles estimated from the ultrasonic system showed a root mean square error (RMSE) of 2.85° ± 0.57° with the reference system. Statistical analysis indicated great agreements between these two systems with a Pearson's correlation coefficient (PCC) value larger than 0.99 for all joint angles' estimation. These results show that the proposed ultrasonic measurement system is useful for applications, such as rehabilitation and sports. PMID:25915589

  5. Quantification of inertial sensor-based 3D joint angle measurement accuracy using an instrumented gimbal.

    PubMed

    Brennan, A; Zhang, J; Deluzio, K; Li, Q

    2011-07-01

    This study quantified the accuracy of inertial sensors in 3D anatomical joint angle measurement with respect to an instrumented gimbal. The gimbal rotated about three axes and directly measured the angles in the ISB recommended knee joint coordinate system. Through the use of sensor attachment devices physically fixed to the gimbal, the joint angle estimation error due to sensor attachment (the inaccuracy of the sensor attachment matrix) was essentially eliminated, leaving only error due to the inertial sensors. The angle estimation error (RMSE) corresponding to the sensor was found to be 3.20° in flexion/extension, 3.42° in abduction/adduction and 2.88° in internal/external rotation. Bland-Altman means of maximum absolute value were -1.63° inflexion/extension, 3.22° in abduction/adduction and -2.61° in internal/external rotation. The magnitude of the errors reported in this study imply that even under ideal conditions irreproducible in human gait studies, inertial angle measurement will be subject to errors of a few degrees. Conversely, the reported errors are smaller than those reported previously in human gait studies, which suggest that the sensor attachment is also significant source of error in inertial gait measurement. The proposed apparatus and methodology could be used to quantify the performance of different sensor systems and orientation estimation algorithms, and to verify experimental protocols before human experimentation. PMID:21715167

  6. The effect of angle and moment of the hip and knee joint on iliotibial band hardness.

    PubMed

    Tateuchi, Hiroshige; Shiratori, Sakiko; Ichihashi, Noriaki

    2015-02-01

    Although several studies have described kinematic deviations such as excessive hip adduction in patients with iliotibial band (ITB) syndrome, the factors contributing to increased ITB hardness remains undetermined, owing to lack of direct in vivo measurement. The purpose of this study was to clarify the factors contributing to an increase in ITB hardness by comparing the ITB hardness between the conditions in which the angle, moment, and muscle activity of the hip and knee joint are changed. Sixteen healthy individuals performed the one-leg standing under five conditions in which the pelvic and trunk inclination were changed in the frontal plane. The shear elastic modulus in the ITB was measured as an indicator of the ITB hardness using shear wave elastography. The three-dimensional joint angle and external joint moment in the hip and knee joints, and muscle activities of the gluteus maximus, gluteus medius, tensor fasciae latae, and vastus lateralis, which anatomically connect to the ITB, were also measured. ITB hardness was significantly increased in the posture with pelvic and trunk inclination toward the contralateral side of the standing leg compared with that in all other conditions (increase of approximately 32% compared with that during normal one-leg standing). This posture increased both the hip adduction angle and external adduction moment at the hip and knee joint, although muscle activities were not increased. Our findings suggest that coexistence of an increased adduction moment at the hip and knee joints with an excessive hip adduction angle lead to an increase in ITB hardness. PMID:25542398

  7. Assessment of novel digital and smartphone goniometers for measurement of canine stifle joint angles.

    PubMed

    Freund, Kristin A; Kieves, Nina R; Hart, Juliette L; Foster, Sasha A; Jeffery, Unity; Duerr, Felix M

    2016-07-01

    OBJECTIVE To evaluate accuracy and reliability of 3 novel goniometers for measurement of canine stifle joint angles and compare the results with those obtained with a universal goniometer (UG). SAMPLE 8 pelvic limbs from 4 canine cadavers. PROCEDURES Each limb was secured to a wooden platform at 3 arbitrarily selected fixed stifle joint angles. Goniometry was performed with 2 smartphone-based applications (novel goniometers A and B), a digital goniometer (novel goniometer C), and a UG; 3 evaluators performed measurements in triplicate for each angle with each device. Results were compared with stifle joint angle measurements on radiographs (used as a gold standard). Accuracy was determined by calculation of bias and total error, coefficients of variation were calculated to estimate reliability, and strength of linear association between radiographic and goniometer measurements was assessed by calculation of correlation coefficients. RESULTS Mean coefficient of variation was lowest for the UG (4.88%), followed by novel goniometers B (7.37%), A (7.57%), and C (12.71%). Correlation with radiographic measurements was highest for the UG (r = 0.97), followed by novel goniometers B (0.93), A (0.90), and C (0.78). Constant bias was present for all devices except novel goniometer B. The UG and novel goniometer A had positive constant bias; novel goniometer C had negative constant bias. Total error at 50° and 100° angles was > 5% for all devices. CONCLUSIONS AND CLINICAL RELEVANCE None of the devices accurately represented radiographically measured stifle joint angles. Additional veterinary studies are indicated prior to the use of novel goniometers in dogs. PMID:27347828

  8. The effect of an active vibration stimulus according to different shoulder joint angles on functional reach and stability of the shoulder joint

    PubMed Central

    Kim, Eun-Kyung; Kim, Seong-Gil

    2016-01-01

    [Purpose] The purpose of this study was to analyze the effect of an active vibration stimulus exercise according to shoulder joint angles on functional reach and stability of the shoulder joint. [Subjects and Methods] Thirty healthy male students participated in this study. Upper limb length of each subject was measured to obtain normalized measurement values. The exercise groups were as follows: group I (n=10, shoulder joint angle of 90°), group II (n=10, shoulder joint angle of 130°), and group III (n=10, shoulder joint angle of 180°). After warm-up, an active vibration stimulus was applied to the subjects with a Flexi-Bar. The Functional Reach Test and Y-balance test were conducted for measurement of shoulder stability. [Results] Analysis of covariance was conducted with values before the intervention as covariates to analyze the differences among the groups in the two tests. There were significant differences among the groups. According to Bonferroni post hoc comparison, group I showed greater improvement than group III in the Functional Reach Test, and group II showed greater improvement than group I and group III in the Y-balance test. [Conclusion] The effect of the exercise with different shoulder joint angles revealed that the shoulder joint has a certain effective joint angle for its functionality and stability. In addition, application of an active vibration stimulus with a Flexi-Bar can be a very effective tool for improvement of functionality and stability of the shoulder joint. PMID:27134352

  9. Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

    PubMed

    Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

    2016-09-01

    Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle. PMID:26863585

  10. Mobile Phone-Based Joint Angle Measurement for Functional Assessment and Rehabilitation of Proprioception

    PubMed Central

    Mourcou, Quentin; Fleury, Anthony; Diot, Bruno; Franco, Céline; Vuillerme, Nicolas

    2015-01-01

    Assessment of joint functional and proprioceptive abilities is essential for balance, posture, and motor control rehabilitation. Joint functional ability refers to the capacity of movement of the joint. It may be evaluated thereby measuring the joint range of motion (ROM). Proprioception can be defined as the perception of the position and of the movement of various body parts in space. Its role is essential in sensorimotor control for movement acuity, joint stability, coordination, and balance. Its clinical evaluation is commonly based on the assessment of the joint position sense (JPS). Both ROM and JPS measurements require estimating angles through goniometer, scoliometer, laser-pointer, and bubble or digital inclinometer. With the arrival of Smartphones, these costly clinical tools tend to be replaced. Beyond evaluation, maintaining and/or improving joint functional and proprioceptive abilities by training with physical therapy is important for long-term management. This review aims to report Smartphone applications used for measuring and improving functional and proprioceptive abilities. It identifies that Smartphone applications are reliable for clinical measurements and are mainly used to assess ROM and JPS. However, there is lack of studies on Smartphone applications which can be used in an autonomous way to provide physical therapy exercises at home. PMID:26583101

  11. Mobile Phone-Based Joint Angle Measurement for Functional Assessment and Rehabilitation of Proprioception.

    PubMed

    Mourcou, Quentin; Fleury, Anthony; Diot, Bruno; Franco, Céline; Vuillerme, Nicolas

    2015-01-01

    Assessment of joint functional and proprioceptive abilities is essential for balance, posture, and motor control rehabilitation. Joint functional ability refers to the capacity of movement of the joint. It may be evaluated thereby measuring the joint range of motion (ROM). Proprioception can be defined as the perception of the position and of the movement of various body parts in space. Its role is essential in sensorimotor control for movement acuity, joint stability, coordination, and balance. Its clinical evaluation is commonly based on the assessment of the joint position sense (JPS). Both ROM and JPS measurements require estimating angles through goniometer, scoliometer, laser-pointer, and bubble or digital inclinometer. With the arrival of Smartphones, these costly clinical tools tend to be replaced. Beyond evaluation, maintaining and/or improving joint functional and proprioceptive abilities by training with physical therapy is important for long-term management. This review aims to report Smartphone applications used for measuring and improving functional and proprioceptive abilities. It identifies that Smartphone applications are reliable for clinical measurements and are mainly used to assess ROM and JPS. However, there is lack of studies on Smartphone applications which can be used in an autonomous way to provide physical therapy exercises at home. PMID:26583101

  12. No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

    PubMed

    Gibson, W; Campbell, A; Allison, G

    2013-09-01

    Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. PMID:23791780

  13. Comparison of the tibial mechanical joint orientation angles in dogs with cranial cruciate ligament rupture

    PubMed Central

    Fuller, Mark C.; Kapatkin, Amy S.; Bruecker, Kenneth A.; Holsworth, Ian G.; Kass, Philip H.; Hayashi, Kei

    2014-01-01

    Use of the tibial mechanical joint orientation angles is now the standard of care for evaluating tibial deformities, although they have not been used to evaluate dogs with cranial cruciate ligament (CrCL) rupture. The objective of this study was to compare the tibial mechanical joint orientation angles and tibial plateau angle (TPA) between dogs with bilateral CrCL rupture (BR) and unilateral CrCL rupture with (UR-SR) and without subsequent contralateral CrCL rupture (UR-w/o-SR) as risk factors for subsequent contralateral CrCL rupture. Twenty dogs (21.7%) were classified as BR, 38 (41.3%) were classified as UR-SR, and 34 (37.0%) were classified as UR-w/o-SR. The tibial mechanical joint orientation angles and TPA, in the range studied (< 35°), were not statistically different for dogs with BR, UR-SR, and UR-w/o-SR, and were not significant risk factors for subsequent contralateral CrCL rupture. PMID:25082991

  14. A literature review on optimum and preferred joint angles in automotive sitting posture.

    PubMed

    Schmidt, Susanne; Amereller, Maximilian; Franz, Matthias; Kaiser, Ralf; Schwirtz, Ansgar

    2014-03-01

    In this study, a survey of the scientific literature in the field of optimum and preferred human joint angles in automotive sitting posture was conducted by referring to thirty different sources published between 1940 and today. The strategy was to use only sources with numerical angle data in combination with keywords. The aim of the research was to detect commonly used joint angles in interior car design. The main analysis was on data measurement, usability and comparability of the different studies. In addition, the focus was on the reasons for the differently described results. It was found that there is still a lack of information in methodology and description of background. Due to these reasons published data is not always usable to design a modern ergonomic car environment. As a main result of our literature analysis we suggest undertaking further research in the field of biomechanics and ergonomics to work out scientific based and objectively determined "optimum" joint angles in automotive sitting position. PMID:23664245

  15. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints

    PubMed Central

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-01-01

    Statement of the Problem Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. Purpose The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. Materials and Method A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (p< 0.05). Results The mean tensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Conclusion Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint. PMID:26636118

  16. A proposal for a new definition of the axial rotation angle of the shoulder joint.

    PubMed

    Masuda, Tadashi; Ishida, Akimasa; Cao, Lili; Morita, Sadao

    2008-02-01

    The Euler/Cardan angles are commonly used to define the motions of the upper arm with respect to the trunk. This definition, however, has a problem in that the angles of both the horizontal flexion/extension and the axial rotation of the shoulder joint become unstable at the gimbal-lock positions. In this paper, a new definition of the axial rotation angle was proposed. The proposed angle was stable over the entire range of the shoulder motion. With the new definition, the neutral position of the axial rotation agreed with that in the conventional anatomy. The advantage of the new definition was demonstrated by measuring actual complex motions of the shoulder with a three-dimensional motion capture system. PMID:17070702

  17. Modeling of 3-D Object Manipulation by Multi-Joint Robot Fingers under Non-Holonomic Constraints and Stable Blind Grasping

    NASA Astrophysics Data System (ADS)

    Arimoto, Suguru; Yoshida, Morio; Bae, Ji-Hun

    This paper derives a mathematical model that expresses motion of a pair of multi-joint robot fingers with hemi-spherical rigid ends grasping and manipulating a 3-D rigid object with parallel flat surfaces. Rolling contacts arising between finger-ends and object surfaces are taken into consideration and modeled as Pfaffian constraints from which constraint forces emerge tangentially to the object surfaces. Another noteworthy difference of modeling of motion of a 3-D object from that of a 2-D object is that the instantaneous axis of rotation of the object is fixed in the 2-D case but that is time-varying in the 3-D case. A further difficulty that has prevented us to model 3-D physical interactions between a pair of fingers and a rigid object lies in the problem of treating spinning motion that may arise around the opposing axis from a contact point between one finger-end with one side of the object to another contact point. This paper shows that, once such spinning motion stops as the object mass center approaches just beneath the opposition axis, then this cease of spinning evokes a further nonholonomic constraint. Hence, the multi-body dynamics of the overall fingers-object system is subject to non-holonomic constraints concerning a 3-D orthogonal matrix expressing three mutually orthogonal unit vectors fixed at the object together with an extra non-holonomic constraint that the instantaneous axis of rotation of the object is always orthogonal to the opposing axis. It is shown that Lagrange's equation of motion of the overall system can be derived without violating the causality that governs the non-holonomic constraints. This immediately suggests possible construction of a numerical simulator of multi-body dynamics that can express motion of the fingers and object physically interactive to each other. By referring to the fact that human grasp an object in the form of precision prehension dynamically and stably by using opposable force between the thumb and another

  18. PARALIND-based blind joint angle and delay estimation for multipath signals with uniform linear array

    NASA Astrophysics Data System (ADS)

    Liu, Xu; Guang, Liang; Yang, Longxiang; Zhu, Hongbo

    2012-12-01

    A novel joint angle and delay estimation (JADE) algorithm for multipath signals, based on the PARAllel profiles with LINear Dependencies (PARALIND) model, is proposed. Capitalizing on the structure property of Vandermonde matrices, PARALIND model is proved to be unique. Angle and delay of multiple rays of sources can be estimated by PARALIND decomposition and an ESPRIT-like shift-invariance technique. Simulation results show that the proposed algorithm outperforms the traditional JADE algorithm. It can automatically distinguish the estimated parameters between sources, and still be available when the number of rays is larger than the number of receiving antennae.

  19. Assessment of Workspace Attributes Under Simulated Index Finger Proximal Interphalangeal Arthrodesis.

    PubMed

    Arauz, Paul G; Sisto, Sue A; Kao, Imin

    2016-05-01

    This article presented an assessment of quantitative measures of workspace (WS) attributes under simulated proximal interphalangeal (PIP) joint arthrodesis of the index finger. Seven healthy subjects were tested with the PIP joint unconstrained (UC) and constrained to selected angles using a motion analysis system. A model of the constrained finger was developed in order to address the impact of the inclusion of prescribed joint arthrodesis angles on WS attributes. Model parameters were obtained from system identification experiments involving flexion-extension (FE) movements of the UC and constrained finger. The data of experimental FE movements of the constrained finger were used to generate the two-dimensional (2D) WS boundaries and to validate the model. A weighted criterion was formulated to define an optimal constraint angle among several system parameters. Results indicated that a PIP joint immobilization angle of 40-50 deg of flexion maximized the 2D WS. The analysis of the aspect ratio of the 2D WS indicated that the WS was more evenly distributed as the imposed PIP joint constraint angle increased. With the imposed PIP joint constraint angles of 30 deg, 40 deg, 50 deg, and 60 deg of flexion, the normalized maximum distance of fingertip reach was reduced by approximately 3%, 4%, 7%, and 9%, respectively. PMID:26974649

  20. Mesofluidic controlled robotic or prosthetic finger

    SciTech Connect

    Lind, Randall F; Jansen, John F; Love, Lonnie J

    2013-11-19

    A mesofluidic powered robotic and/or prosthetic finger joint includes a first finger section having at least one mesofluidic actuator in fluid communication with a first actuator, a second mesofluidic actuator in fluid communication with a second actuator and a second prosthetic finger section pivotally connected to the first finger section by a joint pivot, wherein the first actuator pivotally cooperates with the second finger to provide a first mechanical advantage relative to the joint point and wherein the second actuator pivotally cooperates with the second finger section to provide a second mechanical advantage relative to the joint point.

  1. Human Joint Angle Estimation with Inertial Sensors and Validation with A Robot Arm.

    PubMed

    El-Gohary, Mahmoud; McNames, James

    2015-07-01

    Traditionally, human movement has been captured primarily by motion capture systems. These systems are costly, require fixed cameras in a controlled environment, and suffer from occlusion. Recently, the availability of low-cost wearable inertial sensors containing accelerometers, gyroscopes, and magnetometers have provided an alternative means to overcome the limitations of motion capture systems. Wearable inertial sensors can be used anywhere, cannot be occluded, and are low cost. Several groups have described algorithms for tracking human joint angles. We previously described a novel approach based on a kinematic arm model and the Unscented Kalman Filter (UKF). Our proposed method used a minimal sensor configuration with one sensor on each segment. This paper reports significant improvements in both the algorithm and the assessment. The new model incorporates gyroscope and accelerometer random drift models, imposes physical constraints on the range of motion for each joint, and uses zero-velocity updates to mitigate the effect of sensor drift. A high-precision industrial robot arm precisely quantifies the performance of the tracker during slow, normal, and fast movements over continuous 15-min recording durations. The agreement between the estimated angles from our algorithm and the high-precision robot arm reference was excellent. On average, the tracker attained an RMS angle error of about 3(°) for all six angles. The UKF performed slightly better than the more common Extended Kalman Filter. PMID:25700438

  2. Morphometric assessment of the canine hip joint using the acetabular angle of retrotorsion.

    PubMed

    Doskarova, B; Kyllar, M; Paral, V

    2010-01-01

    Morphometric assessment of the canine hip joint using acetabular angle of retrotorsion was used in this study. The aim of our study was to compare the acetabular angle of retrotorsion (AAR) with values of the Norberg angle (NA) and the hip score (HS) in the Leonberger dog breed and to determine the cut-off point of AAR that distinguish between normal and dysplastic hip status on the basis of Fédération Cynologique Internationale (FCI) hip evaluation. Retrospective analysis of NA and AAR was measured from standard ventrodorsal pelvic radiographs with extended femurs in 387 Leonberger dogs (141 males and 246 females) from 18 to 63 months of age, which were then divided into five age-groups. Through analysis of these radiographs, it was determined that the cut-off point for NA was 105°, AAR was 15°, and the acetabular angle of retrotorsion was positively correlated with Norberg angle and negatively correlated with hip score. The results of our study indicate that the acetabular angle of retrotorsion may represent a reliable morphometric assessment tool in evaluating acetabular cup conformation, and values of AAR may help to assess the FCI grade of canine hip dysplasia. PMID:20740259

  3. Muscle and reflex changes with varying joint angle in hemiparetic stroke

    PubMed Central

    Mirbagheri, Mehdi M; Alibiglou, Laila; Thajchayapong, Montakan; Rymer, William Z

    2008-01-01

    Background Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint. Methods Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM). Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls. Results Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position. Conclusion In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated. Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects, suggesting that the non

  4. INDIVIDUAL OPTIMAL FREQUENCY IN WHOLE BODY VIBRATION: EFFECT OF PROTOCOL, JOINT ANGLE AND FATIGUING EXERCISE.

    PubMed

    Carlucci, Flaminia; Felici, Francesco; Piccinini, Alberto; Haxhi, Jonida; Sacchetti, Massimo

    2013-04-12

    Recent studies have shown the importance of individualizing the vibration intervention in order to produce greater effects on the neuromuscular system in less time. The purpose of this study was to assess theindividualoptimalvibration frequency (O.V.F.)corresponding to the highestmuscle activation (RMSmax) duringvibrationat differentfrequencies, comparing different protocols. Twenty-nine university students underwent 3 Continuous (C) and 2 Random (R) different vibrating protocols, maintaining a squat position on a vibration platform. The C protocol lasted 50 seconds and involved the succession of ascending frequencies from 20 to 55 Hz, every 5 seconds. The same protocol was performed twice, having the knee angle at 120° (C) and 90° (C90), in order to assess the effect of joint angle, and after a fatiguing squatting exercise (CF) to evaluate the influence of fatigue on O.V.F. assessment. In therandomprotocols vibration time was 20 seconds with a 2-minute (R2) and a 4-minute (R4) pauses between tested frequencies. Muscle activation and O.V.F. values did not differ significantly in the C, R2 and R4 protocols. RMSmax was higher in C90 (p< 0.001) and in CF (p = 0.04) compared to the Cprotocol. Joint angle and fatiguing exercise had no effect on optimalvibration frequency. In conclusion, the shorter C protocol produced similar myoelectrical activity in the R2 and the R4 protocols and therefore could be equally valid in identifying the O.V.F. with considerable time efficiency. Knee joint angle and fatiguing exercise had an effect on sEMG response during vibration but did not affect significantly O.V.F. identification. PMID:23588483

  5. Use of dual Euler angles to quantify the three-dimensional joint motion and its application to the ankle joint complex.

    PubMed

    Ying, Ning; Kim, Wangdo

    2002-12-01

    This paper presents a modified Euler angles method, dual Euler angles approach, to describe general spatial human joint motions. In dual Euler angles approach, the three-dimensional joint motion is considered as three successive screw motions with respect to the axes of the moving segment coordinate system; accordingly, the screw motion displacements are represented by dual Euler angles. The algorithm for calculating dual Euler angles from coordinates of markers on the moving segment is also provided in this study. As an example, the proposed method is applied to describe motions of ankle joint complex during dorsiflexion-plantarflexion. A Flock of Birds electromagnetic tracking device (FOB) was used to measure joint motion in vivo. Preliminary accuracy tests on a gimbal structure demonstrate that the mean errors of dual Euler angles evaluated by using source data from FOB are less than 1 degrees for rotations and 1mm for translations, respectively. Based on the pilot study, FOB is feasible for quantifying human joint motions using dual Euler angles approach. PMID:12445618

  6. Joint mean angle of arrival, angular and Doppler spreads estimation in macrocell environments

    NASA Astrophysics Data System (ADS)

    Rejeb, Nessrine Ben; Bousnina, Inès; Ben Salah, Mohamed Bassem; Samet, Abdelaziz

    2014-12-01

    In this paper, we propose a new low-complexity joint estimator of the mean angle of arrival (AoA), the angular spread (AS), and the maximum Doppler spread (DS) for single-input multiple-output (SIMO) wireless channel configurations in a macrocell environment. The non-line-of-sight (NLOS) case is considered. The space-time correlation matrix is used to jointly estimate the three parameters. Closed-form expressions are developed for the desired parameters using the modules and the phases of the cross-correlation coefficients. Simulation results show that our approach offers a better tradeoff between computational complexity and accuracy than the most recent estimators in the literature.

  7. A portable system for collecting anatomical joint angles during stair ascent: a comparison with an optical tracking device

    PubMed Central

    Bergmann, Jeroen HM; Mayagoitia, Ruth E; Smith, Ian CH

    2009-01-01

    Background Assessments of stair climbing in real-life situations using an optical tracking system are lacking, as it is difficult to adapt the system for use in and around full flights of stairs. Alternatively, a portable system that consists of inertial measurement units (IMUs) can be used to collect anatomical joint angles during stair ascent. The purpose of this study was to compare the anatomical joint angles obtained by IMUs to those calculated from position data of an optical tracking device. Methods Anatomical joint angles of the thigh, knee and ankle, obtained using IMUs and an optical tracking device, were compared for fourteen healthy subjects. Joint kinematics obtained with the two measurement devices were evaluated by calculating the root mean square error (RMSE) and by calculating a two-tailed Pearson product-moment correlation coefficient (r) between the two signals. Results Strong mean correlations (range 0.93 to 0.99) were found for the angles between the two measurement devices, as well as an average root mean square error (RMSE) of 4 degrees over all the joint angles, showing that the IMUs are a satisfactory system for measuring anatomical joint angles. Conclusion These highly portable body-worn inertial sensors can be used by clinicians and researchers alike, to accurately collect data during stair climbing in complex real-life situations. PMID:19389238

  8. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs

    PubMed Central

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-01-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles. PMID:26357447

  9. Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb.

    PubMed

    Anderson, Dennis E; Madigan, Michael L; Nussbaum, Maury A

    2007-01-01

    Measurements of human strength can be important during analyses of physical activities. Such measurements have often taken the form of the maximum voluntary torque at a single joint angle and angular velocity. However, the available strength varies substantially with joint position and velocity. When examining dynamic activities, strength measurements should account for these variations. A model is presented of maximum voluntary joint torque as a function of joint angle and angular velocity. The model is based on well-known physiological relationships between muscle force and length and between muscle force and velocity and was tested by fitting it to maximum voluntary joint torque data from six different exertions in the lower limb. Isometric, concentric and eccentric maximum voluntary contractions were collected during hip extension, hip flexion, knee extension, knee flexion, ankle plantar flexion and dorsiflexion. Model parameters are reported for each of these exertion directions by gender and age group. This model provides an efficient method by which strength variations with joint angle and angular velocity may be incorporated into comparisons between joint torques calculated by inverse dynamics and the maximum available joint torques. PMID:17485097

  10. Joint space aspect reconstruction of wide-angle SAR exploiting sparsity

    NASA Astrophysics Data System (ADS)

    Stojanovic, Ivana; Cetin, Mujdat; Karl, William C.

    2008-04-01

    In this paper we present an algorithm for wide-angle synthetic aperture radar (SAR) image formation. Reconstruction of wide-angle SAR holds a promise of higher resolution and better information about a scene, but it also poses a number of challenges when compared to the traditional narrow-angle SAR. Most prominently, the isotropic point scattering model is no longer valid. We present an algorithm capable of producing high resolution reflectivity maps in both space and aspect, thus accounting for the anisotropic scattering behavior of targets. We pose the problem as a non-parametric three-dimensional inversion problem, with two constraints: magnitudes of the backscattered power are highly correlated across closely spaced look angles and the backscattered power originates from a small set of point scatterers. This approach considers jointly all scatterers in the scene across all azimuths, and exploits the sparsity of the underlying scattering field. We implement the algorithm and present reconstruction results on realistic data obtained from the XPatch Backhoe dataset.

  11. Variability and similarity of gait as evaluated by joint angles: implications for forensic gait analysis.

    PubMed

    Yang, Sylvia X M; Larsen, Peter K; Alkjær, Tine; Simonsen, Erik B; Lynnerup, Niels

    2014-03-01

    Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual’s VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60–80 in the gait cycle. We show how our data can assess gait data from an actual case. PMID:24745080

  12. Joint image formation and anisotropy characterization in wide-angle SAR

    NASA Astrophysics Data System (ADS)

    Varshney, Kush R.; Çetin, Müjdat; Fisher, John W., III; Willsky, Alan S.

    2006-05-01

    We consider the problem of jointly forming images and characterizing anisotropy from wide-angle synthetic aperture radar (SAR) measurements. Conventional SAR image formation techniques assume isotropic scattering, which is not valid with wide-angle apertures. We present a method based on a sparse representation of aspect-dependent scattering with an overcomplete basis composed of basis vectors with varying levels of angular persistence. Solved as an inverse problem, the result is a complex-valued, aspect-dependent response for each spatial location in a scene. Our non-parametric approach does not suffer from reduced cross-range resolution inherent in subaperture methods and considers all point scatterers in a scene jointly. The choice of the overcomplete basis set incorporates prior knowledge of aspect-dependent scattering, but the method is flexible enough to admit solutions that may not match a family of parametric functions. We enforce sparsity through regularization based on the l k-norm, k < 1. This formulation leads to an optimization problem that is solved through a robust quasi-Newton method. We also develop a graph-structured interpretation of the overcomplete basis leading towards approximate algorithms using guided depth-first search with appropriate stopping conditions and search heuristics. We present experimental results on synthetic scenes and the backhoe public release dataset.

  13. An evaluation of the spring finger solder joints on SA1358-10 and SA2052-4 connector assemblies (MC3617,W87).

    SciTech Connect

    Kilgo, Alice C.; Vianco, Paul Thomas; Hlava, Paul Frank; Zender, Gary L.

    2006-08-01

    The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder joint used to attach the beryllium-copper (BeCu) spring fingers to the aluminum (Al) connector shell: (1) extended cracking within the fillet; (2) remelting of the solder joint during the follow-on, soldering step that attached the EMR adapter ring to the connector shell (and/or soldering the EMR shell to the adapter ring) that used the lower melting temperature 63Sn-37Pb (Sn-Pb) alloy; and (3) spalling of the Cd (Cr) layer overplating layer from the fillet surface. Several pedigrees of connectors were evaluated, which represented older fielded units as well as those assemblies that were recently constructed at Kansas City Plant. The solder joints were evaluated that were in place on connectors made with the current soldering process as well as an alternative induction soldering process for attaching the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely reflected the different extents to which the connector was mated to its counterpart assembly. In all cases, the spring finger solder joints on the SA1358-10 connectors were remelted as a result of the subsequent EMR adapter ring attachment process. Spalling of the Cd (Cr) overplating layer was also observed for these connectors, which was a consequence of the remelting activity. On the other hand, the SA2052-4 connector did not exhibit evidence of

  14. Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

    PubMed

    Dumas, R; Cheze, L

    2008-08-01

    Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses. PMID:18206375

  15. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas M. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2013-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  16. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert J., Jr. (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2014-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  17. EVALUATION OF THE INTERMETATARSAL ANGLE AFTER THE ARTHRODESIS OF THE FIRST METATARSOPHALANGEAL JOINT FOR TREATMENT OF THE HALLUX VALGUS

    PubMed Central

    Costa, Marco Túlio; Neto, Douglas Lobato Lopes; Kojima, Fábio Henrique; Ferreira, Ricardo Cardenuto

    2015-01-01

    Objective: To evaluate the correction of the intermetatarsal angle after arthrodesis of the metatarsophalangeal joint of the hallux. We believe that varus deformity of the first metatarsal can be corrected after arthrodesis of the first metatarsophalangeal joint, without the need for proximal osteotomy. Methods: Forty-three feet of patients who had undergone arthrodesis of the first metatarsophalangeal joint between May 1997 and October 2009 were retrospectively analyzed by means of radiographs. The mean length of follow-up was 58 months. Measurements on the metatarsophalangeal angle, intermetatarsal angle and sesamoid dislocation were made using radiographs made before, immediately after and later on after the operation. Results: The mean metatarsophalangeal angle was 37.6 degrees preoperatively, 12.8 degrees immediately after the operation and 16.4 degrees later on after the operation. The mean intermetatarsal angle was 16 degrees preoperatively, 10 degrees immediately after the operation and 10.2 degrees later on after the operation. Regarding sesamoid dislocation, preoperative radiographs showed most feet to be classified as G3; immediately after the operation, most were classified as G2; and later on after the operation, most were G1. Conclusion: The intermetatarsal angle and sesamoid dislocation improved with arthrodesis of the first metatarsophalangeal joint, without the need for osteotomy at the base of the first metatarsal. PMID:27042648

  18. Finger pain

    MedlinePlus

    Pain - finger ... Nearly everyone has had finger pain at some time. You may have: Tenderness Burning Stiffness Numbness Tingling Coldness Swelling Change in skin color Redness Many conditions, such ...

  19. Design and characterization of a wearable macrobending fiber optic sensor for human joint angle determination

    NASA Astrophysics Data System (ADS)

    Silva, Ana S.; Catarino, André; Correia, Miguel V.; Frazão, Orlando

    2013-12-01

    The work presented here describes the development and characterization of intensity fiber optic sensor integrated in a specifically designed piece of garment to measure elbow flexion. The sensing head is based on macrobending incorporated in the garment, and the increase of curvature number was studied in order to investigate which scheme provided a good result in terms of sensitivity and repeatability. Results showed the configuration that assured a higher sensitivity (0.644 dBm/deg) and better repeatability was the one with four loops. Ultimately, this sensor can be used for rehabilitation purposes to monitor human joint angles, namely, elbow flexion on stroke survivors while performing the reach functional task, which is the most common upper-limb human gesture.

  20. Detecting Elementary Arm Movements by Tracking Upper Limb Joint Angles With MARG Sensors.

    PubMed

    Mazomenos, Evangelos B; Biswas, Dwaipayan; Cranny, Andy; Rajan, Amal; Maharatna, Koushik; Achner, Josy; Klemke, Jasmin; Jobges, Michael; Ortmann, Steffen; Langendorfer, Peter

    2016-07-01

    This paper reports an algorithm for the detection of three elementary upper limb movements, i.e., reach and retrieve, bend the arm at the elbow and rotation of the arm about the long axis. We employ two MARG sensors, attached at the elbow and wrist, from which the kinematic properties (joint angles, position) of the upper arm and forearm are calculated through data fusion using a quaternion-based gradient-descent method and a two-link model of the upper limb. By studying the kinematic patterns of the three movements on a small dataset, we derive discriminative features that are indicative of each movement; these are then used to formulate the proposed detection algorithm. Our novel approach of employing the joint angles and position to discriminate the three fundamental movements was evaluated in a series of experiments with 22 volunteers who participated in the study: 18 healthy subjects and four stroke survivors. In a controlled experiment, each volunteer was instructed to perform each movement a number of times. This was complimented by a seminaturalistic experiment where the volunteers performed the same movements as subtasks of an activity that emulated the preparation of a cup of tea. In the stroke survivors group, the overall detection accuracy for all three movements was 93.75% and 83.00%, for the controlled and seminaturalistic experiment, respectively. The performance was higher in the healthy group where 96.85% of the tasks in the controlled experiment and 89.69% in the seminaturalistic were detected correctly. Finally, the detection ratio remains close ( ±6%) to the average value, for different task durations further attesting to the algorithms robustness. PMID:25966489

  1. Radiological Assessment of the Sacrofemoral Angle: A Novel Method to Measure the Range of Hip Joint Flexion

    PubMed Central

    Wei, Xian-Zhao; Xu, Xi-Ming; Wang, Fei; Li, Ming; Wang, Zi-Min

    2015-01-01

    Background: A quantitative and accurate measurement of the range of hip joint flexion (RHF) is necessarily required in the evaluation of disordered or artificial hip joint function. This study aimed to assess a novel method to measure RHF more accurately and objectively. Methods: Lateral radiographs were taken of 31 supine men with hip joints extended or flexed. Relevant angles were measured directly from the radiographs. The change in the sacrofemoral angle (SFA) (the angle formed between the axis of the femur and the line tangent to the upper endplate of S1) from hip joint extension to hip joint flexion, was proposed as the RHF. The validity of this method was assessed via concomitant measurements of changes in the femur-horizontal angle (between the axis of the femur and the horizontal line) and the sacrum-horizontal angle (SHA) (between the line tangent to the upper endplate of S1 and the horizontal line), the difference of which should equal the change in the SFA. Results: The mean change in the SFA was 112.5 ± 7.4°, and was independent of participant age, height, weight, or body mass index. The mean changes in the femur-horizontal and SHAs were 123.0 ± 6.4° and 11.4 ± 3.0°, respectively. This confirmed that the change of SFA between hip joint extension and hip joint flexion was equal to the difference between the changes in the femur-horizontal and SHAs. Conclusions: Using the SFA, to evaluate RHF could prevent compromised measurements due to the movements of pelvis and lumbar spine during hip flexion, and is, therefore, a more accurate and objective method with reasonable reliability and validity. PMID:26315079

  2. Limited-angle multi-energy CT using joint clustering prior and sparsity regularization

    NASA Astrophysics Data System (ADS)

    Zhang, Huayu; Xing, Yuxiang

    2016-03-01

    In this article, we present an easy-to-implement Multi-energy CT scanning strategy and a corresponding reconstruction method, which facilitate spectral CT imaging by improving the data efficiency the number-of-energy- channel fold without introducing visible limited-angle artifacts caused by reducing projection views. Leveraging the structure coherence at different energies, we first pre-reconstruct a prior structure information image using projection data from all energy channels. Then, we perform a k-means clustering on the prior image to generate a sparse dictionary representation for the image, which severs as a structure information constraint. We com- bine this constraint with conventional compressed sensing method and proposed a new model which we referred as Joint Clustering Prior and Sparsity Regularization (CPSR). CPSR is a convex problem and we solve it by Alternating Direction Method of Multipliers (ADMM). We verify our CPSR reconstruction method with a numerical simulation experiment. A dental phantom with complicate structures of teeth and soft tissues is used. X-ray beams from three spectra of different peak energies (120kVp, 90kVp, 60kVp) irradiate the phantom to form tri-energy projections. Projection data covering only 75◦ from each energy spectrum are collected for reconstruction. Independent reconstruction for each energy will cause severe limited-angle artifacts even with the help of compressed sensing approaches. Our CPSR provides us with images free of the limited-angle artifact. All edge details are well preserved in our experimental study.

  3. Influence of Joint Angle on EMG-Torque Model During Constant-Posture, Torque-Varying Contractions.

    PubMed

    Liu, Pu; Liu, Lukai; Clancy, Edward A

    2015-11-01

    Relating the electromyogram (EMG) to joint torque is useful in various application areas, including prosthesis control, ergonomics and clinical biomechanics. Limited study has related EMG to torque across varied joint angles, particularly when subjects performed force-varying contractions or when optimized modeling methods were utilized. We related the biceps-triceps surface EMG of 22 subjects to elbow torque at six joint angles (spanning 60° to 135°) during constant-posture, torque-varying contractions. Three nonlinear EMG σ -torque models, advanced EMG amplitude (EMG σ ) estimation processors (i.e., whitened, multiple-channel) and the duration of data used to train models were investigated. When EMG-torque models were formed separately for each of the six distinct joint angles, a minimum "gold standard" error of 4.01±1.2% MVC(F90) resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so achieved a statistically equivalent error of 4.06±1.2% MVC(F90). Results demonstrated that advanced EMG σ processors lead to improved joint torque estimation as do longer model training durations. PMID:25706722

  4. Locking Plate in Proximal Tibial Fracture: A Correlation between the Coronal Alignment of Tibia and Joint Screw Angle

    PubMed Central

    Oh, Jong-Keon; Varte, Lalrinliana; Ko, Jae-Han; Oh, Chang-Wug; Jung, Duk-Young; An, Hyonggin; Cho, Jae-Woo

    2013-01-01

    Purpose The purpose of this study is to evaluate the relationship between the angle formed between the proximal most screw through the locking compression plate-proximal lateral tibia (LCP PLT) and the joint line, and to evaluate if this angle can be used intraoperatively as an assessment tool to determine normal alignment of the tibia in the coronal plane. Materials and Methods There are two parts to this study: in the first part, LCP PLT was applied to 30 cadaveric adult tibia. The angle between the joint line and the proximal most screw was measured and termed as the 'joint screw angle' (JSA). In the second part, 56 proximal tibial fractures treated with LCP PLT were retrospectively studied. Two angles were measured on the radiographs, the medial proximal tibial angle (MPTA) and the JSA. Their relationship was analyzed statistically. Results The average JSA was 1.16 degrees in the anatomical study. Statistical analysis of the clinical study showed that the normal MPTA had a direct correlation with an acceptable JSA. Conclusion We therefore conclude that the JSA can be used intraoperatively to assess the achievement of a normal coronal axis. PMID:23549821

  5. A dowel exercise tool to improve finger range of motion.

    PubMed

    Zavala, Paul

    2014-01-01

    A new clinical and home dowel exercise tool to reduce joint stiffness of the fingers is introduced, along with the fabrication and the exercises that are used with it. Patients may utilize it to improve their finger joint range of motion, and facilitate tendon glide by isolating the targeted stiff joints of the fingers. PMID:24044953

  6. Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life.

    PubMed

    Tognetti, Alessandro; Lorussi, Federico; Carbonaro, Nicola; de Rossi, Danilo

    2015-01-01

    Human motion analysis is crucial for a wide range of applications and disciplines. The development and validation of low cost and unobtrusive sensing systems for ambulatory motion detection is still an open issue. Inertial measurement systems and e-textile sensors are emerging as potential technologies for daily life situations. We developed and conducted a preliminary evaluation of an innovative sensing concept that combines e-textiles and tri-axial accelerometers for ambulatory human motion analysis. Our sensory fusion method is based on a Kalman filter technique and combines the outputs of textile electrogoniometers and accelerometers without making any assumptions regarding the initial accelerometer position and orientation. We used our technique to measure the flexion-extension angle of the knee in different motion tasks (monopodalic flexions and walking at different velocities). The estimation technique was benchmarked against a commercial measurement system based on inertial measurement units and performed reliably for all of the various tasks (mean and standard deviation of the root mean square error of 1:96 and 0:96, respectively). In addition, the method showed a notable improvement in angular estimation compared to the estimation derived by the textile goniometer and accelerometer considered separately. In future work, we will extend this method to more complex and multi-degree of freedom joints. PMID:26569249

  7. Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life

    PubMed Central

    Tognetti, Alessandro; Lorussi, Federico; Carbonaro, Nicola; de Rossi, Danilo

    2015-01-01

    Human motion analysis is crucial for a wide range of applications and disciplines. The development and validation of low cost and unobtrusive sensing systems for ambulatory motion detection is still an open issue. Inertial measurement systems and e-textile sensors are emerging as potential technologies for daily life situations. We developed and conducted a preliminary evaluation of an innovative sensing concept that combines e-textiles and tri-axial accelerometers for ambulatory human motion analysis. Our sensory fusion method is based on a Kalman filter technique and combines the outputs of textile electrogoniometers and accelerometers without making any assumptions regarding the initial accelerometer position and orientation. We used our technique to measure the flexion-extension angle of the knee in different motion tasks (monopodalic flexions and walking at different velocities). The estimation technique was benchmarked against a commercial measurement system based on inertial measurement units and performed reliably for all of the various tasks (mean and standard deviation of the root mean square error of 1.96 and 0.96∘, respectively). In addition, the method showed a notable improvement in angular estimation compared to the estimation derived by the textile goniometer and accelerometer considered separately. In future work, we will extend this method to more complex and multi-degree of freedom joints. PMID:26569249

  8. Morphometric assessment of the canine hip joint using the dorsal acetabular rim view and the centre-edge angle.

    PubMed

    Meomartino, L; Fatone, G; Potena, A; Brunetti, A

    2002-01-01

    The dorsal acetabular rim (DAR) view of the hip joint can be used to assess the weightbearing portion of the acetabulum and the acetabular coverage, providing an adjunct to the conventional ventrodorsal (VD) view in the radiographic evaluation of hip dysplasia in the dog. A quantitative index of acetabular coverage in the DAR view, the acetabular slope (AS) angle, was originally proposed in 1990. The aim of the present study was to make a prospective, comparative assessment of a new parameter, the centre-edge (CE) angle, with the AS angle, for the evaluation of the acetabular coverage of the femoral head in the DAR view. The reliability and repeatability of the two parameters was assessed using the r(I) value of intraclass correlation coefficient (ICC) in a prospective study of 208 hip joints in large and giant breed dogs. An estimation of the added value of using the DAR view, compared with that of the VD standard view alone, was also assessed. The CE angle showed a higher r(I) value compared with the AS angle; in 26 per cent of hips of FCI classes A, B and C, the DAR view provided additional diagnostic information compared with the VD view, with respect to lateralisation and/or initial changes to the dorsal rim. It is concluded that the CE angle is more reliable than the AS angle in the evaluation of acetabular coverage, and that the DAR view provides valuable data compared with the VD view alone in the early stages of canine hip dysplasia. PMID:11833819

  9. Mallet finger - aftercare

    MedlinePlus

    Baseball finger - aftercare; Drop finger - aftercare; Avulsion fracture - mallet finger - aftercare ... Mallet finger occurs when you cannot straighten your finger: when you try to straighten it, the tip of your ...

  10. Development and Applications of a Self-Contained, Non-Invasive EVA Joint Angle and Muscle Fatigue Sensor System

    NASA Technical Reports Server (NTRS)

    Ranniger, C. U.; Sorenson, E. A.; Akin, D. L.

    1995-01-01

    The University of Maryland Space Systems Laboratory, as a participant in NASA's INSTEP program, is developing a non-invasive, self-contained sensor system which can provide quantitative measurements of joint angles and muscle fatigue in the hand and forearm. The goal of this project is to develop a system with which hand/forearm motion and fatigue metrics can be determined in various terrestrial and zero-G work environments. A preliminary study of the prototype sensor systems and data reduction techniques for the fatigue measurement system are presented. The sensor systems evaluated include fiberoptics, used to measure joint angle, surface electrodes, which measure the electrical signals created in muscle as it contracts; microphones, which measure the noise made by contracting muscle; and accelerometers, which measure the lateral muscle acceleration during contraction. The prototype sensor systems were used to monitor joint motion of the metacarpophalangeal joint and muscle fatigue in flexor digitorum superficialis and flexor carpi ulnaris in subjects performing gripping tasks. Subjects were asked to sustain a 60-second constant-contraction (isometric) exercise and subsequently to perform a repetitive handgripping task to failure. Comparison of the electrical and mechanical signals of the muscles during the different tasks will be used to evaluate the applicability of muscle signal measurement techniques developed for isometric contraction tasks to fatigue prediction in quasi-dynamic exercises. Potential data reduction schemes are presented.

  11. Accuracy of visual estimates of joint angle and angular velocity using criterion movements.

    PubMed

    Morrison, Craig S; Knudson, Duane; Clayburn, Colby; Haywood, Philip

    2005-06-01

    A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement. PMID:16060418

  12. Effect of Hip Angle on Anterior Hip Joint Force during Gait

    PubMed Central

    Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.

    2010-01-01

    Anterior hip or groin pain is a common complaint for which people are referred for physical therapy. We have observed that people with anterior hip pain often walk in greater hip extension than people without anterior hip pain, and that the pain is reduced when they walk in less hip extension. Therefore, we investigated anterior hip joint forces which may contribute to anterior hip pain and examined the effect of end range hip extension on the anterior hip joint force during gait. To do this, we used a 6 degree of freedom, 3-dimensional musculoskeletal model to estimate hip joint forces during gait. Within subjects, the maximum anterior hip joint force for gait trials with the most hip extension was compared to the anterior hip joint force for gait trials with the least hip extension. The musculoskeletal model indicated that increasing the maximum end range hip extension when walking results in an increase in the anterior hip joint force when compared to walking in less hip extension. Walking in greater hip extension may result in an increase in the anterior hip joint force, and thereby contribute to anterior hip pain. The findings of this study provide some evidence supporting the use of gait modification to reduce anterior hip force when treating people with anterior hip pain. PMID:20934338

  13. Radiographic evaluation of perching-joint angles in cockatiels (Nymphicus hollandicus), Hispaniolan Amazon parrots (Amazona ventralis), and barred owls (Strix varia).

    PubMed

    Bonin, Glen; Lauer, Susanne K; Guzman, David Sanchez-Migallon; Nevarez, Javier; Tully, Thomas N; Hosgood, Giselle; Gaschen, Lorrie

    2009-06-01

    Information on perching-joint angles in birds is limited. Joint immobilization in a physiologic perching angle has the potential to result more often in complete restoration of limb function. We evaluated perching-joint angles in 10 healthy cockatiels (Nymphicus hollandicus), 10 Hispaniolan Amazons (Amazona ventralis), and 9 barred owls (Strix varia) and determined intra- and interobserver variability for goniometric measurements in 2 different radiographic projections. Intra- and interobserver variation was less than 7% for all stifle and intertarsal joint measurements but frequently exceeded 10% for the hip-joint measurements. Hip, stifle, and intertarsal perching angles differed significantly among cockatiels, Hispaniolan Amazon parrots, and barred owls. The accuracy of measurements performed on straight lateral radiographic projections with superimposed limbs was not consistently superior to measurements on oblique projections with a slightly rotated pelvis. Stifle and intertarsal joint angles can be measured on radiographs by different observers with acceptable variability, but intra- and interobserver variability for hip-joint-angle measurements is higher. PMID:19673455

  14. Improvements of Travel-time Tomography Models from Joint Inversion of Multi-channel and Wide-angle Seismic Data

    NASA Astrophysics Data System (ADS)

    Begović, Slaven; Ranero, César; Sallarès, Valentí; Meléndez, Adrià; Grevemeyer, Ingo

    2016-04-01

    Commonly multichannel seismic reflection (MCS) and wide-angle seismic (WAS) data are modeled and interpreted with different approaches. Conventional travel-time tomography models using solely WAS data lack the resolution to define the model properties and, particularly, the geometry of geologic boundaries (reflectors) with the required accuracy, specially in the shallow complex upper geological layers. We plan to mitigate this issue by combining these two different data sets, specifically taking advantage of the high redundancy of multichannel seismic (MCS) data, integrated with wide-angle seismic (WAS) data into a common inversion scheme to obtain higher-resolution velocity models (Vp), decrease Vp uncertainty and improve the geometry of reflectors. To do so, we have adapted the tomo2d and tomo3d joint refraction and reflection travel time tomography codes (Korenaga et al, 2000; Meléndez et al, 2015) to deal with streamer data and MCS acquisition geometries. The scheme results in a joint travel-time tomographic inversion based on integrated travel-time information from refracted and reflected phases from WAS data and reflected identified in the MCS common depth point (CDP) or shot gathers. To illustrate the advantages of a common inversion approach we have compared the modeling results for synthetic data sets using two different travel-time inversion strategies: We have produced seismic velocity models and reflector geometries following typical refraction and reflection travel-time tomographic strategy modeling just WAS data with a typical acquisition geometry (one OBS each 10 km). Second, we performed joint inversion of two types of seismic data sets, integrating two coincident data sets consisting of MCS data collected with a 8 km-long streamer and the WAS data into a common inversion scheme. Our synthetic results of the joint inversion indicate a 5-10 times smaller ray travel-time misfit in the deeper parts of the model, compared to models obtained using just

  15. Finger Stiffness.

    PubMed

    Oosterhoff, Thijs C H; Nota, Sjoerd P F T; Ring, David

    2015-06-01

    Background Finger stiffness varies substantially in patients with hand and upper extremity illness and can be notably more than expected for a given pathophysiology. In prior studies, pain intensity and magnitude of disability consistently correlate with coping strategies such as catastrophic thinking and kinesiophobia, which can be characterized as overprotectiveness. In this retrospective study we address the primary research question whether patients with finger stiffness are more often overprotective when the primary pathology is outside the hand (e.g. distal radius fracture) than when it is located within the hand. Methods In an orthopaedic hand surgery department 160 patients diagnosed with more finger stiffness than expected for a given pathophysiology or time point of recovery between December 2006 and September 2012 were analyzed to compare the proportion of patients characterized as overprotective for differences by site of pathology: (1) inside the hand, (2) outside the hand, and (3) psychiatric etiology (e.g. clenched fist). Results Among 160 subjects with more finger stiffness than expected, 132 (82 %) were characterized as overprotective including 88 of 108 (81 %) with pathology in the hand, 39 of 44 (89 %) with pathology outside the hand, and 5 of 8 (63 %) with psychiatric etiology. These differences were not significant. Conclusions Overprotectiveness is common in patients with more finger stiffness than expected regardless the site and type of primary pathology. It seems worthwhile to recognize and treat maladaptive coping strategies early during recovery to limit impairment, symptoms, and disability. PMID:26078497

  16. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  17. Joint angle and Doppler frequency estimation of coherent targets in monostatic MIMO radar

    NASA Astrophysics Data System (ADS)

    Cao, Renzheng; Zhang, Xiaofei

    2015-05-01

    This paper discusses the problem of joint direction of arrival (DOA) and Doppler frequency estimation of coherent targets in a monostatic multiple-input multiple-output radar. In the proposed algorithm, we perform a reduced dimension (RD) transformation on the received signal first and then use forward spatial smoothing (FSS) technique to decorrelate the coherence and obtain joint estimation of DOA and Doppler frequency by exploiting the estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm. The joint estimated parameters of the proposed RD-FSS-ESPRIT are automatically paired. Compared with the conventional FSS-ESPRIT algorithm, our RD-FSS-ESPRIT algorithm has much lower complexity and better estimation performance of both DOA and frequency. The variance of the estimation error and the Cramer-Rao Bound of the DOA and frequency estimation are derived. Simulation results show the effectiveness and improvement of our algorithm.

  18. Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress fields

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Aydin, Atilla; Pollard, David D.

    2000-01-01

    Structural methods based on homogeneous stress states predict that joints growing in an extending crust form with strike orientations identical to normal faults. However, we document a field example where the strikes of genetically related normal faults and joints are almost mutually perpendicular. Field relationships allowed us to constrain the fracture sequence and tectonic environment for fault and joint growth. We hypothesize that fault slip can perturb the surrounding stress field in a manner that controls the orientations of induced secondary structures. Numerical models were used to examine the stress field around normal faults, taking into consideration the effects of 3-D fault shape, geometrical arrangement of overlapping faults, and a range of stress states. The calculated perturbed stress fields around model normal faults indicate that it is possible for joints to form at high angles to fault strike. Such joint growth may occur at the lateral tips of an isolated fault, but is most likely in a relay zone between overlapping faults. However, the angle between joints and faults is also influenced by the remote stress state, and is particularly sensitive to the ratio of fault-parallel to fault-perpendicular stress. As this ratio increases, joints can propagate away from faults at increasingly higher angles to fault strike. We conclude that the combined remote stress state and perturbed local stress field associated with overlapping fault geometries resulted in joint growth at high angles to normal fault strike at a field location in Arches National Park, Utah.

  19. Finger Multiplication

    ERIC Educational Resources Information Center

    Holmes, Bill

    2010-01-01

    The author has been prompted to write this article about finger multiplication for a number of reasons. Firstly there are a number of related articles in past issues of "Mathematics Teaching" ("MT") which have connections to this algorithm. Secondly, very few of his primary teaching students and professional colleagues appear to be aware of the…

  20. Joint and angle-covariant spin measurements with a quadrupole magnetic field

    NASA Technical Reports Server (NTRS)

    Martens, Hans; Demuynck, Willem M.

    1994-01-01

    We study a Stern-Gerlach type setup, with a quadrupole magnetic field, for neutral particles of arbitrary spin. The Hamiltonian is of a form proposed for joint measurements of the incompatible observables. The measurement results are discussed, showing the limitation of such Hamiltonians. Some remarks are made on the relevance of covariance as a criterion for measurement schemes.

  1. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    PubMed

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension. PMID:24941915

  2. Robust Pilot Decontamination Based on Joint Angle and Power Domain Discrimination

    NASA Astrophysics Data System (ADS)

    Yin, Haifan; Cottatellucci, Laura; Gesbert, David; Muller, Ralf R.; He, Gaoning

    2016-06-01

    We address the problem of noise and interference corrupted channel estimation in massive MIMO systems. Interference, which originates from pilot reuse (or contamination), can in principle be discriminated on the basis of the distributions of path angles and amplitudes. In this paper we propose novel robust channel estimation algorithms exploiting path diversity in both angle and power domains, relying on a suitable combination of the spatial filtering and amplitude based projection. The proposed approaches are able to cope with a wide range of system and topology scenarios, including those where, unlike in previous works, interference channel may overlap with desired channels in terms of multipath angles of arrival or exceed them in terms of received power. In particular we establish analytically the conditions under which the proposed channel estimator is fully decontaminated. Simulation results confirm the overall system gains when using the new methods.

  3. Effects of pelvic adjustment on pelvic posture and angles of the lower limb joints during walking in female university students

    PubMed Central

    Cho, Misuk

    2016-01-01

    [Purpose] This study investigated the effects of pelvic adjustment on pelvic posture and lower limb joint angles during walking in female university students. [Subjects] Thirty healthy female university students were randomly assigned to an experimental group (pelvic adjustment group, n = 15) and a control group (stretching group, n = 15). [Methods] Pelvic adjustment was performed three times on the experimental group. The control group performed three sets of pelvic muscle stretching for 15 minutes. A back mapper and motion analysis equipment were used to measure pelvic posture and angles of lower limb joints for the experimental and control group. [Results] The values obtained before and after the intervention were compared. For the experimental group, the results were significantly different in terms of reduced differences in hip flexion between the left and right hips and in knee abduction between the left and right knees. Differences in pelvic position and pelvic torsion were also found in the experimental group. No significant differences in the control group were identified. [Conclusion] Pelvic adjustment affects pelvic position and torsion and this enhancement to pelvic stability decreases hip flexion and knee abduction during walking. PMID:27190468

  4. The relationship between unilateral mandibular angle fracture and temporomandibular joint function.

    PubMed

    Baltrusaityte, Ausra; Surna, Algimantas; Pileicikiene, Gaivile; Kubilius, Ricardas; Gleiznys, Alvydas; Zilinskas, Juozas

    2014-01-01

    PURPOSE. Aim of this study was to analyze relation of occlusal correction and alterations of temporomandibular joint function during treatment of unilateral mandibular fractures. MATERIALS AND METHODS. We compared 49 patients treated for unilateral mandibular fracture without occlusal correction with 21 patient treated for unilateral mandibular fracture along with early and consequent occlusal analysis and correction and with 49 control subjects. Patients' complaints, mandibular movements and occlusal parameters were evaluated during the period of healing. ZEBRIS ultrasound system (Jaw Motion Analyzer, Zebris Medical GmbH, Isny, Germany) was used for analysis of mandibular movements and T-Scan analyzer (Tekscan, Inc., Boston, MA, USA) was used for occlusal analysis. RESULTS. Findings of our study showed statistically significant (p<0.05) diminution of patients complaints, mandibular movement alterations and occlusal disturbances in patients who received occlusal correction during MF treatment if compared to patients treated without occlusal correction, except noises from the joint in the injured side and mandibular lateral track to the injured side in the final stage of investigation. Despite applied treatment recovery of the TMJ function was not complete and the investigated parameters remained worse if compared to the control group. CONCLUSIONS. Results of this study confirmed positive influence of early and subsequent occlusal analysis and correction during stages of MF treatment on diminution of functional alterations of the temporomandibular joint function. Timely occlusal correction improves and hastens process of rehabilitation therefore it is indispensable part of MF treatment. PMID:25471992

  5. Joint Replacement (Finger and Wrist Joints)

    MedlinePlus

    ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ...

  6. Comparison of Multi-angle Imaging SpectroRadiometer (MISR) joint aerosol product with high-resolution model output

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O.; Lee, H.; Suzuki, K.; Braverman, A. J.

    2014-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Level 3 Joint Aerosol product (JOINT_AS) provides global, descriptive summary of MISR Level 2 aerosol optical thickness (AOT) for eight different types of aerosols at 5 x 5 degrees of horizontal resolution in each month between March 2000 and present. Using Version 22 JOINT_AS, this study analyzed characteristics of the observed AOT distributions and compared various statistical moments of aerosol optical thickness derived from JOINT_AS with the results from Nonhydrostatic Icosahedral Atmospheric Model (NICAM) simulation. Overall, marginal distributions of AOT show highly positive skewness at many grid points. Some of the large skewness values are related to the problems in MISR's retrieval algorithm. For example, the positive skewness in AOT for strongly absorbing aerosols at mid- and high latitudes in winter results from few outlier values is due to cloud contamination over a wide area. Combined AOT for multiple MISR aerosol types is comparable to the AOT for carbonaceous, sulfate aerosols and dust particles from the NICAM simulation implemented with aerosol transport processes. NICAM's carbonaceous aerosols in the Southwest Africa show good agreement with MISR's strongly absorbing aerosols. The AOT of dust particles in MISR and NICAM exhibit similar spatial patterns over the Sahara desert. The AOT of nonabsorbing aerosols in MISR well represents spatial distributions of the sulfate aerosols originating from industrial complex over the Shandong Peninsula in China. Our results indicate that MISR's AOT for each aerosol type may be useful for monitoring biomass burning, dust storms and air pollution and evaluating chemistry climate models.

  7. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Ihrke, Chris A. (Inventor); Reiland, Matthew J. (Inventor); Wampler, Charles W. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Bridgwater, Lyndon (Inventor)

    2013-01-01

    A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

  8. Comparison of joint angles and electromyographic activity of the lower extremities during standing with wearing standard and revised high-heeled shoes: A pilot study.

    PubMed

    Bae, Young-Hyeon; Ko, Mansoo; Lee, Suk Min

    2016-04-29

    Revised high-heeled shoes (HHSs) were designed to improve the shortcomings of standard HHSs. This study was conducted to compare revised and standard HHSs with regard to joint angles and electromyographic (EMG) activity of the lower extremities during standing. The participants were five healthy young women. Data regarding joint angles and EMG activity of the lower extremities were obtained under three conditions: barefoot, when wearing revised HHSs, and when wearing standard HHSs. Lower extremity joint angles in the three dimensional plane were confirmed using a VICON motion capture system. EMG activity of the lower extremities was measured using active bipolar surface EMG. Kruskal-Wallis one-way analysis of variance by rank applied to analyze differences during three standing conditions. Compared with the barefoot condition, the standard HHSs condition was more different than the revised HHSs condition with regard to lower extremity joint angles during standing. EMG activity of the lower extremities was different for the revised HHSs condition, but the differences among the three conditions were not significant. Wearing revised HHSs may positively impact joint angles and EMG activity of the lower extremities by improving body alignment while standing. PMID:27163313

  9. A structural design methodology for large angle articulated trusses considering realistic joint modeling

    NASA Astrophysics Data System (ADS)

    Thorwald, Gregory; Mikulas, Martin M., Jr.

    1994-01-01

    A structural design methodology is developed by quantifying the magnitude that large angle articulations and realistic modeling considerations adversely affect a truss's structural stiffness. Batten actuators provide the ability for the truss both to deploy and articulate. Such an articulated truss can be used in space crane applications. With geometry and modeling considerations identified and examined, strategies to alleviate the truss's stiffness reduction are developed and evaluated. Using these strategies, an improved articulated truss is then demonstrated. Observing that the design strategies are effective for the planar truss models similar 3-D truss models are then analyzed. The results show that the improvement strategies benefit both the 2-D and 3-D truss models.

  10. Behaviour of the electrical impedance myography in isometric contraction of biceps brachii at different elbow joint angles

    NASA Astrophysics Data System (ADS)

    Coutinho, A. B. B.; Jotta, B.; Pino, A. V.; Souza, M. N.

    2012-12-01

    Electrical impedance myography (EIM) can be understood as an experimental technique applied to evaluate bioelectrical impedance associated to the muscular activity. With the development of technique, some studies are trying to associate the EIM parameters with the morphological and physiological changes that occur in the muscle during contraction. In this context this work sought to associate EIM parameters observed during isometric contractions of the biceps brachii muscle at different elbow joint angles with the correspondent muscular force. Differently from previous works that did not observe significant correlation between those data, our findings point to high correlations between the some EIM resistive parameters and the muscle force. Despite the need of further investigation, our results indicated that EIM technique can be used to estimate muscle force in a noninvasive way.

  11. A Unitary ESPRIT Scheme of Joint Angle Estimation for MOTS MIMO Radar

    PubMed Central

    Wen, Chao; Shi, Guangming

    2014-01-01

    The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme. PMID:25106023

  12. A unitary ESPRIT scheme of joint angle estimation for MOTS MIMO radar.

    PubMed

    Wen, Chao; Shi, Guangming

    2014-01-01

    The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme. PMID:25106023

  13. Estimations of relative effort during sit-to-stand increase when accounting for variations in maximum voluntary torque with joint angle and angular velocity.

    PubMed

    Bieryla, Kathleen A; Anderson, Dennis E; Madigan, Michael L

    2009-02-01

    The main purpose of this study was to compare three methods of determining relative effort during sit-to-stand (STS). Fourteen young (mean 19.6+/-SD 1.2 years old) and 17 older (61.7+/-5.5 years old) adults completed six STS trials at three speeds: slow, normal, and fast. Sagittal plane joint torques at the hip, knee, and ankle were calculated through inverse dynamics. Isometric and isokinetic maximum voluntary contractions (MVC) for the hip, knee, and ankle were collected and used for model parameters to predict the participant-specific maximum voluntary joint torque. Three different measures of relative effort were determined by normalizing STS joint torques to three different estimates of maximum voluntary torque. Relative effort at the hip, knee, and ankle were higher when accounting for variations in maximum voluntary torque with joint angle and angular velocity (hip=26.3+/-13.5%, knee=78.4+/-32.2%, ankle=27.9+/-14.1%) compared to methods which do not account for these variations (hip=23.5+/-11.7%, knee=51.7+/-15.0%, ankle=20.7+/-10.4%). At higher velocities, the difference in calculating relative effort with respect to isometric MVC or incorporating joint angle and angular velocity became more evident. Estimates of relative effort that account for the variations in maximum voluntary torque with joint angle and angular velocity may provide higher levels of accuracy compared to methods based on measurements of maximal isometric torques. PMID:17720539

  14. Integration of marker and force data to compute three-dimensional joint moments of the thumb and index finger digits during pinch

    PubMed Central

    Nataraj, Raviraj; Li, Zong-Ming

    2014-01-01

    This study presents methodology to determine joint moments of the digits of the hand during pinch function. This methodology incorporates steps to identify marker-based kinematic data defining aligned coordinate systems for individual digit segments and joint center locations. The kinematic data are then transformed to a common reference frame along with the force data collected at pinch contact of a customized apparatus in three-dimensions (3-D). These methods were demonstrated with a pilot investigation to examine the static joint moments occurring during two-digit oppositional precision pinch at a particular endpoint force level applied at the digit pads. Notable abduction joint moments at the proximal joints of both digits were observed, which implicate the role of respective intrinsic and extrinsic muscles in maintaining pinch grasp. Examining differences in joint moment results when substituting select steps of this methodological approach suggested greater relative importance for joint center identification and segment coordinate system alignment. PMID:23947659

  15. Finger Injuries and Disorders

    MedlinePlus

    You use your fingers and thumbs to do everything from grasping objects to playing musical instruments to typing. When there is something wrong ... the skin of your palm. It causes the fingers to stiffen and bend. Trigger finger - an irritation ...

  16. High cycles fatigue damage of CFRP plates clamped by bolts for axial coupling joint with off-set angle during rotation

    NASA Astrophysics Data System (ADS)

    Ooka, Kazuaki; Okubo, Kazuya; Fujii, Toru; Umeda, Shinichi; Fujii, Masayuki; Sugiyama, Tetsuya

    2014-03-01

    This study discussed the change of residual fracture torque and the fatigue damage process of thin CFRP plates clamped by bolts for axial coupling joint, in which flexible deformation was allowed in the direction of off-set angle by the deflection of the CFRP plates while effective stiffness was obtained in rotational direction. Mechanically laminated 4 layers of the CFRP plates were repeatedly deflected during the rotation of axial coupling, when two axes were jointed with 3 degree of off-set angle, in which number of revolution was 1,800 rpm (30Hz of loading frequency). At first, the fracture morphology of specimen and the residual fracture torque was investigated after 1.0×107 cycles of repeated revolutions. The reduction ratio of spring constant was also determined by simple bending test after the fatigue. The residual fracture torque of the joint was determined on the rotational test machine after 1.0×107 cycles of fatigue. After rotations of cyclic fatigue, fiber breaking and wear of matrix were observed around the fixed parts compressed by washers for setting bolts. The reduction of spring constant of the CFRP plates was caused by the initiation of cyclic fatigue damages around the fixed parts, when the axial coupling joint was rotated with off-set angle. It was found that residual fracture torque of the joint was related with the specific fatigue damage of the CFRP observed in this study.

  17. Design and preliminary evaluation of the FINGER rehabilitation robot: controlling challenge and quantifying finger individuation during musical computer game play

    PubMed Central

    2014-01-01

    Background This paper describes the design and preliminary testing of FINGER (Finger Individuating Grasp Exercise Robot), a device for assisting in finger rehabilitation after neurologic injury. We developed FINGER to assist stroke patients in moving their fingers individually in a naturalistic curling motion while playing a game similar to Guitar Hero®a. The goal was to make FINGER capable of assisting with motions where precise timing is important. Methods FINGER consists of a pair of stacked single degree-of-freedom 8-bar mechanisms, one for the index and one for the middle finger. Each 8-bar mechanism was designed to control the angle and position of the proximal phalanx and the position of the middle phalanx. Target positions for the mechanism optimization were determined from trajectory data collected from 7 healthy subjects using color-based motion capture. The resulting robotic device was built to accommodate multiple finger sizes and finger-to-finger widths. For initial evaluation, we asked individuals with a stroke (n = 16) and without impairment (n = 4) to play a game similar to Guitar Hero® while connected to FINGER. Results Precision design, low friction bearings, and separate high speed linear actuators allowed FINGER to individually actuate the fingers with a high bandwidth of control (−3 dB at approximately 8 Hz). During the tests, we were able to modulate the subject’s success rate at the game by automatically adjusting the controller gains of FINGER. We also used FINGER to measure subjects’ effort and finger individuation while playing the game. Conclusions Test results demonstrate the ability of FINGER to motivate subjects with an engaging game environment that challenges individuated control of the fingers, automatically control assistance levels, and quantify finger individuation after stroke. PMID:24495432

  18. Compromised encoding of proprioceptively determined joint angles in older adults: the role of working memory and attentional load.

    PubMed

    Goble, Daniel J; Mousigian, Marianne A; Brown, Susan H

    2012-01-01

    Perceiving the positions and movements of one's body segments (i.e., proprioception) is critical for movement control. However, this ability declines with older age as has been demonstrated by joint angle matching paradigms in the absence of vision. The aim of the present study was to explore the extent to which reduced working memory and attentional load influence older adult proprioceptive matching performance. Older adults with relatively HIGH versus LOW working memory ability as determined by backward digit span and healthy younger adults, performed memory-based elbow position matching with and without attentional load (i.e., counting by 3 s) during target position encoding. Even without attentional load, older adults with LOW digit spans (i.e., 4 digits or less) had larger matching errors than younger adults. Further, LOW older adults made significantly greater errors when attentional loads were present during proprioceptive target encoding as compared to both younger and older adults with HIGH digit span scores (i.e., 5 digits or greater). These results extend previous position matching results that suggested greater errors in older adults were due to degraded input signals from peripheral mechanoreceptors. Specifically, the present work highlights the role cognitive factors play in the assessment of older adult proprioceptive acuity using memory-based matching paradigms. Older adults with LOW working memory appear prone to compromised proprioceptive encoding, especially when secondary cognitive tasks must be concurrently executed. This may ultimately result in poorer performance on various activities of daily living. PMID:22006273

  19. Noncontacting Finger Seal

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P. (Inventor); Steinetz, Bruce M. (Inventor)

    2004-01-01

    An annular finger seal is adapted to be interposed between a high pressure upstream region and a lower pressure downstream region to provide noncontact sealing along a rotatable member. The finger seal comprises axially juxtaposed downstream and upstream finger elements, each having integrally spaced fingers. The downstream fingers each have a lift pad, whereas the upstream fingers lack a pad. Each pad extends in a downstream direction. Each upstream finger is spaced from the rotating member a greater distance than each pad. Upon sufficient rotational speed of the rotating member, each pad is operative to lift and ride on a thin film of fluid intermediate the rotating member and the Pad.

  20. Articular synovial chondromatosis of the finger.

    PubMed

    Sano, Kazufumi; Hashimoto, Tomohisa; Kimura, Kazumasa; Ozeki, Satoru

    2014-10-01

    A 40-year-old woman presented with a six-month history of synovial chondromatosis of the metacarpophalangeal joint of the right ring finger, which was resected through both dorsal and volar incisions. To our knowledge there have been only 17 reported cases of articular synovial chondromatosis of the digital joint so far. We present a case affecting the metacarpophalangeal joint with a review of scattered information found in other 17 reports. PMID:23596991

  1. Comparisons of knee and ankle joint angles and ground reaction force according to functional differences during single-leg drop landing

    PubMed Central

    Kim, Kewwan; Jeon, Kyoungkyu

    2016-01-01

    [Purpose] The purpose of this study was to determine potential predictors of functional instability of the knee and ankle joints during single-leg drop landing based on the prior history of injury. [Subjects and Methods] The subjects were 24 collegiate soccer players without pain or dysfunction. To compare the differences between the stable and unstable sides during single-leg drop landing, 8 motion analysis cameras and a force plate were used. The Cortex 4 software was used for a biomechanical analysis of 3 events. An independent t-test was used for statistical comparison between both sides; p<0.05 indicated significance. [Results] The knee joint movements showed gradual flexion in the sagittal plane. The unstable-side ankle joint showed plantar flexion of approximately 2° relative to the stable side. In the coronal plane, the unstable-side knee joint differed from the stable side in its tendency for valgus movement. The unstable-side ankle joint showed contrasting movement compared with the stable side, and the difference was significant. Regarding the vertical ground reaction force, the stable side showed maximum knee flexion that was approximately 0.1 BW lower than that of the unstable side. [Conclusion] Increasing the flexion angle of the knee joint can help prevent injury during landing. PMID:27190444

  2. Tumour necrosis factor blockade for the treatment of erosive osteoarthritis of the interphalangeal finger joints: a double blind, randomised trial on structure modification

    PubMed Central

    Verbruggen, Gust; Wittoek, Ruth; Cruyssen, Bert Vander; Elewaut, Dirk

    2012-01-01

    Background Adalimumab blocks the action of tumor necrosis factor-α and reduces disease progression in rheumatoid arthritis and psoriatic arthritis. The effects of adalimumab in controlling progression of structural damage in erosive hand osteoarthritis (HOA) were assessed. Methods Sixty patients with erosive HOA on radiology received 40 mg adalimumab or placebo subcutaneously every two weeks during a 12-month randomized double-blind trial. Response was defined as the reduction in progression of structural damage according to the categorical anatomic phase scoring system. Furthermore, subchondral bone, bone plate erosion, and joint-space narrowing were scored according to the continuous Ghent University Score System (GUSSTM). Results The disease appeared to be active since 40.0% and 26,7% of patients out of the placebo and adalimumab group, respectively, showed at least one new interphalangeal (IP) joint that became erosive during the 12 months follow-up. These differences were not significant and the overall results showed no effect of adalimumab. Risk factors for progression were then identified and the presence of palpable soft tissue swelling at baseline was recognized as the strongest predictor for erosive progression. In this subpopulation at risk, statistically significant less erosive evolution on the radiological image (3.7%) was seen in the adalimumab treated group compared to the placebo group (14.5%) (P = 0.009). GUSSTM scoring confirmed a less rapid rate of mean increase in the erosion scores during the first 6 months of treatment in patients in adalimumab-treated patients. Conclusion Palpable soft tissue swelling in IP joints in patients with erosive HOA is a strong predictor for erosive progression. In these joints adalimumab significantly halted the progression of joint damage compared to placebo. PMID:22128078

  3. Hand and Finger Exercises

    MedlinePlus

    Hand and Finger Exercises  Place your palm flat on a table. Raise and lower your fingers one ... times for ____ seconds.  Pick up objects with your hand. Start out with larger objects. Repeat ____ times for ____ ...

  4. Speed invariance of independent control of finger movements in pianists

    PubMed Central

    Soechting, John F.

    2012-01-01

    Independent control of finger movements characterizes skilled motor behaviors such as tool use and musical performance. The purpose of the present study was to identify the effect of movement frequency (tempo) on individuated finger movements in piano playing. Joint motion at the digits was recorded while 5 expert pianists were playing 30 excerpts from musical pieces with different fingering and key locations either at a predetermined normal tempo or as fast as possible. Principal component analysis and cluster analysis using an expectation-maximization algorithm determined three distinct patterns of finger movement coordination for a keypress with each of the index, middle, ring, and little fingers at each of the two tempi. The finger kinematics of each coordination pattern was overall similar across the tempi. Tone sequences assigned into each cluster were also similar for both tempi. A linear regression analysis determined no apparent difference in the amount of movement covariation between the striking and nonstriking fingers at both metacarpo-phalangeal and proximal-interphalangeal joints across the two tempi, which indicated no effect of tempo on independent finger movements in piano playing. In addition, the standard deviation of interkeystroke interval across strokes did not differ between the two tempi, indicating maintenance of rhythmic accuracy of keystrokes. Strong temporal constraints on finger movements during piano playing may underlie the maintained independent control of fingers over a wider range of tempi, a feature being likely to be specific to skilled pianists. PMID:22815403

  5. Radiographic anatomy of the rabbit skull, with particular reference to the tympanic bulla and temporomandibular joint. Part 2: Ventral and dorsal rotational angles.

    PubMed

    King, A M; Cranfield, F; Hall, J; Hammond, G; Sullivan, M

    2010-11-01

    This is the second part of a two-part study to document rabbit skull radiographic anatomy with particular reference to the temporomandibular joint (TMJ) and tympanic bulla (TB), and identify views that allowed their optimal visualisation. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in ventral (rostrocaudal to ventrodorsal) with the mouth closed and open, and dorsal (rostrocaudal to dorsoventral position) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TBs were visible between 40° and 90° from rostrocaudal in both directions, but opening the mouth did not improve visualisation. The TMJs were visible until 40° in a ventral direction, but only 20° in a dorsal one. Opening the mouth slightly altered the regions of the joint being skylined, but did not otherwise enhance imaging of this region. PMID:19717319

  6. Extrinsic and intrinsic index finger muscle attachments in an OpenSim upper-extremity model.

    PubMed

    Lee, Jong Hwa; Asakawa, Deanna S; Dennerlein, Jack T; Jindrich, Devin L

    2015-04-01

    Musculoskeletal models allow estimation of muscle function during complex tasks. We used objective methods to determine possible attachment locations for index finger muscles in an OpenSim upper-extremity model. Data-driven optimization algorithms, Simulated Annealing and Hook-Jeeves, estimated tendon locations crossing the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints by minimizing the difference between model-estimated and experimentally-measured moment arms. Sensitivity analysis revealed that multiple sets of muscle attachments with similar optimized moment arms are possible, requiring additional assumptions or data to select a single set of values. The most smooth muscle paths were assumed to be biologically reasonable. Estimated tendon attachments resulted in variance accounted for (VAF) between calculated moment arms and measured values of 78% for flex/extension and 81% for ab/adduction at the MCP joint. VAF averaged 67% at the PIP joint and 54% at the DIP joint. VAF values at PIP and DIP joints partially reflected the constant moment arms reported for muscles about these joints. However, all moment arm values found through optimization were non-linear and non-constant. Relationships between moment arms and joint angles were best described with quadratic equations for tendons at the PIP and DIP joints. PMID:25281408

  7. The effects of shoulder joint abduction angles on the muscle activity of the serratus anterior muscle and the upper trapezius muscle while vibrations are applied

    PubMed Central

    Jung, Da-eun; Moon, Dong-chul

    2015-01-01

    [Purpose] The purpose of this study was to examine the ratio between the upper trapezius and the serratus anterior muscles during diverse shoulder abduction exercises applied with vibrations in order to determine the appropriate exercise methods for recovery of scapular muscle balance. [Subjects and Methods] Twenty-four subjects voluntarily participated in this study. The subjects performed shoulder abduction at various shoulder joint abduction angles (90°, 120°, 150°, 180°) with oscillation movements. [Results] At 120°, all the subjects showed significant increases in the muscle activity of the serratus anterior muscle in comparison with the upper trapezius muscle. However, no significant difference was found at angles other than 120°. [Conclusion] To selectively strengthen the serratus anterior, applying vibration stimuli at the 120° shoulder abduction position is considered to be appropriate. PMID:25642052

  8. Radiographic anatomy of the rabbit skull with particular reference to the tympanic bulla and temporomandibular joint: Part 1: Lateral and long axis rotational angles.

    PubMed

    King, A M; Cranfield, F; Hall, J; Hammond, G; Sullivan, M

    2010-11-01

    Radiography is frequently used to investigate otitis media and dental disease in rabbits, although there are few detailed reports regarding the radiographic anatomy of the rabbit skull. The aim of this study was to document rabbit skull radiographic anatomy, with particular reference to the tympanic bulla (TB) and temporomandibular joint (TMJ), and to identify views that allowed optimal assessment of these areas. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in lateral (lateral to rostrocaudal) and long axis (lateral to ventrodorsal) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TB could be best examined between 30° and 60° in both planes. The TMJ was best visualised between 70° and 90° in a lateral direction, particularly along a true rostrocaudal plane, but could not be imaged well at any of the long axis rotational angles. Similar images were obtained using cadavers. PMID:19853482

  9. Finger snapping during seizures.

    PubMed

    Overdijk, M J; Zijlmans, M; Gosselaar, P H; Olivier, A; Leijten, F S S; Dubeau, F

    2014-01-01

    We describe two patients who showed snapping of the right hand fingers during invasive intracranial EEG evaluation for epilepsy surgery. We correlated the EEG changes with the finger-snapping movements in both patients to determine the underlying pathophysiology of this phenomenon. At the time of finger snapping, EEG spread from the supplementary motor area towards the temporal region was seen, suggesting involvement of these sites. PMID:25667884

  10. Fingers that change color

    MedlinePlus

    ... conditions can cause fingers or toes to change color: Buerger disease Chilblains. Painful inflammation of small blood vessels. Cryoglobulinemia Frostbite Necrotizing vasculitis Peripheral artery disease ...

  11. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  12. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  13. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  14. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  15. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  16. Bilateral Volleyball-Related Deformity of the Little Fingers: Mallet Finger and Clinodactyly Mimic

    PubMed Central

    Uslu, Mustafa; Solak, Kazim; Ozsahin, Mustafa; Uzun, Hakan

    2011-01-01

    A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP) joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis. Key points As a result of repeated micro traumas to the physial region, flexion and valgus deformities of the distal interphalangeal (DIP) joints should be occurred. Sports injuries to the hand often require treatment in orthopedic departments to avoid permanent deformities. Short- or long-term functional results can be gained by simple splinting procedures and abstention from play. PMID:24149318

  17. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation

    PubMed Central

    Kim, Yeonghun; Lee, Kunwoo; Moon, Jeheon; Koo, Dohoon; Park, Jaewoo; Kim, Kyengnam; Hong, Daehie; Shin, Inshik

    2014-01-01

    [Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual’s joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training. PMID:24764626

  18. Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults

    PubMed Central

    Park, Mi Hwa; Yu, Jae Ho; Hong, Ji Heon; Kim, Jin Seop; Jung, Sang Woo; Lee, Dong Yeop

    2016-01-01

    [Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength. PMID:27134390

  19. A reverse flow cross finger pedicle skin flap from hemidorsum of finger.

    PubMed

    Mishra, Satyanarayan; Manisundaram, S

    2010-04-01

    A reverse-flow cross-finger pedicle skin flap raised from the hemidorsum has been used, which is a modification of the distally based dorsal cross-finger flap. The flap is raised from the hemidorsum at a plane above the paratenon, the distal-most location of the base being at the level of the distal interphalangeal joint. Thirty-two flaps were used from as many fingers of as many patients. Of these, 31 (97%) flaps survived fully; there was stiffness of finger in one (3%) patient and the two-point discrimination was 4-8mm (n=14). Follow-up period was 2 months to 3 years, the median being 1 year and 3 months. The advantages of this flap are that there is less disruption of veins and less visible disfigurement of the dorsum of the finger when compared to other pedicled cross-finger skin flaps. The disadvantage of this flap is its restricted width. It is recommended as the cross-finger pedicle skin flap of choice when the defect is not wide. PMID:19386561

  20. Rolling friction robot fingers

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1992-01-01

    A low friction, object guidance, and gripping finger device for a robotic end effector on a robotic arm is disclosed, having a pair of robotic fingers each having a finger shaft slideably located on a gripper housing attached to the end effector. Each of the robotic fingers has a roller housing attached to the finger shaft. The roller housing has a ball bearing mounted centering roller located at the center, and a pair of ball bearing mounted clamping rollers located on either side of the centering roller. The object has a recess to engage the centering roller and a number of seating ramps for engaging the clamping rollers. The centering roller acts to position and hold the object symmetrically about the centering roller with respect to the X axis and the clamping rollers act to position and hold the object with respect to the Y and Z axis.

  1. Prediction of contact forces of underactuated finger by adaptive neuro fuzzy approach

    NASA Astrophysics Data System (ADS)

    Petković, Dalibor; Shamshirband, Shahaboddin; Abbasi, Almas; Kiani, Kourosh; Al-Shammari, Eiman Tamah

    2015-12-01

    To obtain adaptive finger passive underactuation can be used. Underactuation principle can be used to adapt shapes of the fingers for grasping objects. The fingers with underactuation do not require control algorithm. In this study a kinetostatic model of the underactuated finger mechanism was analyzed. The underactuation is achieved by adding the compliance in every finger joint. Since the contact forces of the finger depend on contact position of the finger and object, it is suitable to make a prediction model for the contact forces in function of contact positions of the finger and grasping objects. In this study prediction of the contact forces was established by a soft computing approach. Adaptive neuro-fuzzy inference system (ANFIS) was applied as the soft computing method to perform the prediction of the finger contact forces.

  2. Neuro-sliding mode control with modular models for control of knee-joint angle using quadriceps electrical stimulation.

    PubMed

    Ajoudani, Arash; Erfanian, Abbas

    2007-01-01

    In this paper, we propose a control methodology which is based on synergistic combination of a single-neuron controller with sliding mode control (SMC) for control of knee-joint position in paraplegic subjects with quadriceps stimulation. The control law will be switched from the sliding mode control to neural control, when the state trajectory of system enters in some boundary layer around the sliding surface. The main drawback of the standard sliding modes is mostly related to the so-called chattering caused by the high-frequency control switching. The value of switching gain depends on the bounds of system uncertainties. The system with large uncertainties needs to use a higher switching gain. This will, however, result in the high-frequency control switching and chattering across the sliding surface. To avoid such a condition, it is necessary to decrease the system uncertainty. To decrease the uncertainty, an accurate model of the system is required. For this purpose, we present a modular approach to modeling the knee-joint dynamics. Extensive experiments on healthy and paraplegic subjects are provided to demonstrate the robustness, stability and tracking accuracy of the neuro-SMC. The experimental results show that the neuro-SMC provides excellent tracking control for different reference trajectories and could generate control signals to compensate the muscle fatigue. PMID:18002483

  3. Large displacement spherical joint

    DOEpatents

    Bieg, Lothar F.; Benavides, Gilbert L.

    2002-01-01

    A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

  4. Finger and toenail onycholysis.

    PubMed

    Zaias, N; Escovar, S X; Zaiac, M N

    2015-05-01

    Onycholysis - the separation of the nail plate from the nail bed occurs in fingers and toenails. It is diagnosed by the whitish appearance of the separated nail plate from the nail bed. In fingers, the majority is caused by trauma, manicuring, occupational or self-induced behavior. The most common disease producing fingernail onycholysis is psoriasis and pustular psoriasis. Phototoxic dermatitis, due to drugs can also produce finger onycholysis. Once the separation occurs, the environmental flora sets up temporary colonization in the available space. Finger onycholysis is most common in women. Candida albicans is often recovered from the onycholytic space. Many reports, want to associate the yeast as cause and effect, but the data are lacking and the treatment of the candida does not improve finger onycholysis. A reasonable explanation for the frequent isolation of Candida and Pseudomonas in fingernail onycholysis in women, is the close proximity the fingers have to the vaginal and gastrointestinal tract. Fifty per cent of humans harbour C. albicans in the GI tract and it is frequently carried to the vagina during hygienic practices. Finger onycholysis is best treated by drying the nail 'lytic' area with a hair blower, since all colonizing biota are moisture loving and perish in a dry environment. Toenail onycholysis has a very different etiology. It is mechanical, the result of pressure on the toes from the closed shoes, while walking, because of the ubiquitous uneven flat feet producing an asymmetric gait with more pressure on the foot with the flatter sole. PMID:25512134

  5. Multiple Fingers - One Gestalt.

    PubMed

    Lezkan, Alexandra; Manuel, Steven G; Colgate, J Edward; Klatzky, Roberta L; Peshkin, Michael A; Drewing, Knut

    2016-01-01

    The Gestalt theory of perception offered principles by which distributed visual sensations are combined into a structured experience ("Gestalt"). We demonstrate conditions whereby haptic sensations at two fingertips are integrated in the perception of a single object. When virtual bumps were presented simultaneously to the right hand's thumb and index finger during lateral arm movements, participants reported perceiving a single bump. A discrimination task measured the bump's perceived location and perceptual reliability (assessed by differential thresholds) for four finger configurations, which varied in their adherence to the Gestalt principles of proximity (small versus large finger separation) and synchrony (virtual spring to link movements of the two fingers versus no spring). According to models of integration, reliability should increase with the degree to which multi-finger cues integrate into a unified percept. Differential thresholds were smaller in the virtual-spring condition (synchrony) than when fingers were unlinked. Additionally, in the condition with reduced synchrony, greater proximity led to lower differential thresholds. Thus, with greater adherence to Gestalt principles, thresholds approached values predicted for optimal integration. We conclude that the Gestalt principles of synchrony and proximity apply to haptic perception of surface properties and that these principles can interact to promote multi-finger integration. PMID:26863671

  6. Changes in Femoral Posterior Condylar Offset, Tibial Posterior Slope Angle, and Joint Line Height after Cruciate-Retaining Total Knee Arthroplasty

    PubMed Central

    Song, Sang Jun; Kim, Kang Il; Jeong, Ho Yeon

    2016-01-01

    Purpose Changes in the femoral posterior condylar offset (PCO), tibial posterior slope angle (PSA), and joint line height (JLH) after cruciate-retaining total knee arthroplasty (CR-TKA) were evaluated to determine their influence on the flexion angle. Materials and Methods A total of 125 CR-TKAs performed on 110 patients were retrospectively reviewed. Pre- and postoperative PCO, PSA, and JLH were compared using correlation analysis. Independent factors affecting the postoperative flexion angle of the knee were analyzed. Results The PCO was 28.2±2.0 mm (range, 24.5 to 33.1 mm) preoperatively and 26.7±1.8 mm (range, 22.2 to 31.2 mm) postoperatively (r=0.807, p<0.001). The PSA was 10.4°±4.9° (range, 1.6° to 21.2°) preoperatively and decreased to 4.9°±2.0° (2.2° to 10.7°) postoperatively (r=–0.023, p=0.800). The JLH was 16.2±3.0 mm (range, 10.2 to 27.5 mm) preoperatively and 16.1±2.6 mm (range, 11.1 to 24.8 mm) postoperatively (r=0.505, p<0.001). None of the independent factors affected the flexion angle (p>0.291). Conclusions Although the PCO and JLH did not change significantly after CR-TKA, the PSA decreased by 5.5° with a small range of variation. Restoration of the PCO and JLH could promote optimization of knee flexion in spite of the decreased PSA after CR-TKA. PMID:26955610

  7. Social categorization and cooperation in motor joint action: evidence for a joint end-state comfort.

    PubMed

    Dötsch, Dominik; Schubö, Anna

    2015-08-01

    The present study investigated to what extent group membership affects an actor's representation of their partner's task in cooperative joint action. Participants performed a joint pick-and-place task in a naturalistic, breakfast-table-like paradigm which allowed the demonstration of varying degrees of cooperation. Participants transported a wooden cup from one end of a table to the other, with one actor moving it to an intermediate position from where their partner transported it to a goal position. Hand and finger movements were recorded via 3D motion tracking to assess actors' cooperative behavior. Before the joint action task was performed, participants were categorized as belonging to the same or to different groups, supposedly based on an assessment of their cognitive processing styles. Results showed that the orientation of the actors' fingers when picking up the cup was affected by its required angle at the goal position. When placing the cup at the intermediate position, most actors adapted the rotation of the cup's handle to the joint action goal, thereby facilitating the partner's subsequent movement. Male actors demonstrated such cooperative behavior only when performing the task together with an ingroup partner, while female actors demonstrated cooperative behavior irrespective of social categorization. These results suggest that actors tend to represent a partner's end-state comfort and integrate it into their own movement planning in cooperative joint action. However, social factors like group membership may modulate this tendency. PMID:25963752

  8. Fingering in Confined Elastic Layers

    NASA Astrophysics Data System (ADS)

    Biggins, John; Mahadevan, L.; Wei, Z.; Saintyves, Baudouin; Bouchaud, Elizabeth

    2015-03-01

    Fingering has recently been observed in soft highly elastic layers that are confined between and bonded to two rigid bodies. In one case an injected fluid invades the layer in finger-like protrusions at the layer's perimeter, a solid analogue of Saffman-Taylor viscous fingering. In a second case, separation of the rigid bodies (with maintained adhesion to the layer) leads air to the formation of similar fingers at the layer's perimeter. In both cases the finger formation is reversible: if the fluid is removed or the separation reduced, the fingers vanish. In this talk I will discuss a theoretical model for such elastic fingers that shows that the origin of the fingers is large-strain geometric non-linearity in the elasticity of soft solids. Our simplified elastic model unifies the two types of fingering and accurately estimates the thresholds and wavelengths of the fingers.

  9. The Manumeter: A non-obtrusive wearable device for monitoring spontaneous use of the wrist and fingers

    PubMed Central

    Rowe, Justin B.; Friedman, Nizan; Bachman, Mark; Reinkensmeyer, David J.

    2014-01-01

    This paper describes the design and pilot testing of a novel device for unobtrusive monitoring of wrist and hand movement through a sensorized watch and a magnetic ring system called the manumeter. The device senses the magnetic field of the ring through two triaxial magnetometers and records the data to onboard memory which can be analyzed later by connecting the watch unit to a computer. Wrist and finger joint angles are estimated using a radial basis function network. We compared joint angle estimates collected using the manumeter to direct measurements taken using a passive exoskeleton and found that after a 60 minute trial, 95% of the radial/ulnar deviation, wrist flexion/extension and finger flexion/extension estimates were within 2.4, 5.8, and 4.7 degrees of their actual values respectively. The device measured angular distance traveled for these three joints within 10.4%, 4.5%, and 14.3 % of their actual values. The manumeter has potential to improve monitoring of real world use of the hand after stroke and in other applications. PMID:24187216

  10. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  11. Fjord geometry observed in viscous fingering*

    NASA Astrophysics Data System (ADS)

    Thrasher, Matt; Ristroph, Leif; Swinney, Harry L.; Mineev-Weinstein, Mark

    2004-11-01

    Injecting a less viscous fluid (air) into a more viscous fluid (oil) produces an unstable finger of air penetrating into the oil. For sufficiently large forcing, the tip of a finger splits. The region of oil left between adjacent fingers is called a fjord. We characterize the width, widening, and bending of fjords in experiments in a rectangular Hele-Shaw cell. The channel confines air and 50 cS silicone oil between two glass plates, which are 2500 mm long and 250 mm wide with a separation of 0.5 mm. The width of the base of a fjord is found to be approximately one-half of the capillary length scale. From this base, the fjords open with a distribution of angles having a mean of about 9 ^rc, which contradicts theoretical predictions of an opening angle of 0 ^rc (parallel sides). Finally, the centerline of a fjord bends. Lajeunesse and Couder [1] account for the bending of a fjord on a single, one-half width finger. We test the validity of their idea on the tip-splitting of more complicated interfaces and on the widening of fjords. *Supported by ONR [1] E. Lajeunesse and Y. Couder, J. Fluid. Mech. 419, 125 (2000).

  12. Osseointegrated finger prostheses.

    PubMed

    Doppen, P; Solomons, M; Kritzinger, S

    2009-02-01

    Amputation of a digit can lead to functional and psychological problems and patients can benefit from digital prostheses. Unfortunately, standard prostheses are often unstable, particularly when fitted over short amputation stumps. Prosthesis fixation by osseointegration is widely used in oral and extraoral applications and may help avoid the problem of instability. This paper reports the results of four patients with five finger amputations who were treated with osseointegrated implants to attach finger prostheses. One implant failed to osseointegrate and the procedure was abandoned. Three patients were successfully treated to completion of three finger prostheses and are extremely satisfied with their outcomes, both cosmetically and functionally, with osseoperception reported by all three patients. PMID:19091736

  13. Joint Effects of Intraocular Pressure and Myopia on Risk of Primary Open-Angle Glaucoma: The Singapore Epidemiology of Eye Diseases Study

    PubMed Central

    Tham, Yih-Chung; Aung, Tin; Fan, Qiao; Saw, Seang-Mei; Siantar, Rosalynn Grace; Wong, Tien Y.; Cheng, Ching-Yu

    2016-01-01

    We examined the joint effects of intraocular pressure (IOP) and myopia on the risk of primary open angle glaucoma (POAG) in a multi-ethnic Asian population. A total of 9,422 participants (18,469 eyes) in the Singapore Epidemiology of Eye Diseases Study were included. Of them, 213 subjects (273 eyes) had POAG. All participants underwent standardised examinations. The independent and joint effects of IOP and myopia on POAG were examined using logistic regression models. Generalised estimating equation models were used to account for correlation between eyes. Higher IOP, longer axial length, and more negative spherical equivalent were independently associated with POAG, after adjusting for relevant covariates (all P ≤ 0.005). Significant interaction between IOP and myopia on POAG was observed (P interaction = 0.025). Eyes with moderate-to-high myopia (<−3.0 dioptres) with high IOP (≥20 mmHg) were 4.27 times (95% CI, 2.10–8.69) likely to have POAG, compared to eyes without myopia (>−0.5 dioptres) and with IOP <20 mmHg. Eyes with AL of ≥25.5 mm and high IOP (≥20 mmHg) were 16.22 times (95% CI, 7.73 to 34.03) likely to have POAG, compared to eyes with shorter AL (<23.5 mm) and lower IOP (<20 mmHg). These findings may provide additional insights into the pathophysiology of POAG and are particularly relevant for Asian populations. PMID:26758554

  14. Joint Effects of Intraocular Pressure and Myopia on Risk of Primary Open-Angle Glaucoma: The Singapore Epidemiology of Eye Diseases Study.

    PubMed

    Tham, Yih-Chung; Aung, Tin; Fan, Qiao; Saw, Seang-Mei; Siantar, Rosalynn Grace; Wong, Tien Y; Cheng, Ching-Yu

    2016-01-01

    We examined the joint effects of intraocular pressure (IOP) and myopia on the risk of primary open angle glaucoma (POAG) in a multi-ethnic Asian population. A total of 9,422 participants (18,469 eyes) in the Singapore Epidemiology of Eye Diseases Study were included. Of them, 213 subjects (273 eyes) had POAG. All participants underwent standardised examinations. The independent and joint effects of IOP and myopia on POAG were examined using logistic regression models. Generalised estimating equation models were used to account for correlation between eyes. Higher IOP, longer axial length, and more negative spherical equivalent were independently associated with POAG, after adjusting for relevant covariates (all P ≤ 0.005). Significant interaction between IOP and myopia on POAG was observed (P interaction = 0.025). Eyes with moderate-to-high myopia (<-3.0 dioptres) with high IOP (≥20 mmHg) were 4.27 times (95% CI, 2.10-8.69) likely to have POAG, compared to eyes without myopia (>-0.5 dioptres) and with IOP <20 mmHg. Eyes with AL of ≥25.5 mm and high IOP (≥20 mmHg) were 16.22 times (95% CI, 7.73 to 34.03) likely to have POAG, compared to eyes with shorter AL (<23.5 mm) and lower IOP (<20 mmHg). These findings may provide additional insights into the pathophysiology of POAG and are particularly relevant for Asian populations. PMID:26758554

  15. Initial results of finger imaging using photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    van Es, Peter; Biswas, Samir K.; Moens, Hein J. Bernelot; Steenbergen, Wiendelt; Manohar, Srirang

    2014-06-01

    We present a photoacoustic computed tomography investigation on a healthy human finger, to image blood vessels with a focus on vascularity across the interphalangeal joints. The cross-sectional images were acquired using an imager specifically developed for this purpose. The images show rich detail of the digital blood vessels with diameters between 100 μm and 1.5 mm in various orientations and at various depths. Different vascular layers in the skin including the subpapillary plexus could also be visualized. Acoustic reflections on the finger bone of photoacoustic signals from skin were visible in sequential slice images along the finger except at the location of the joint gaps. Not unexpectedly, the healthy synovial membrane at the joint gaps was not detected due to its small size and normal vascularization. Future research will concentrate on studying digits afflicted with rheumatoid arthritis to detect the inflamed synovium with its heightened vascularization, whose characteristics are potential markers for disease activity.

  16. Plasmonic "nano-fingers on nanowires" as SERS substrates.

    PubMed

    Sharma, Yashna; Dhawan, Anuj

    2016-05-01

    A surface-enhanced Raman scattering (SERS) substrate based on plasmonics-active metallic nano-finger arrays grown on arrays of triangular-shaped metal-coated silicon nanowire arrays is proposed. Finite-difference time-domain modeling is employed to numerically calculate the effect of the inter-finger gap and the growth angle of the nano-fingers on the magnitude of SERS enhancement and the plasmon resonance wavelength. Additionally, the polarization dependence of the SERS signals from these novel substrates has been studied. A protocol for the fabrication of the proposed SERS substrate is also discussed. PMID:27128080

  17. Bladder operated robotic joint

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A. (Inventor)

    1993-01-01

    This invention is a robotic joint which is operated by inflatable bladders and which can be used in applications where it is desired to move or hold an object. A support block supports an elongated plate to which is pivotally attached a finger. A tension strip passes over a lever attached to the finger and is attached at its ends to the support block on opposite sides of the plate. Bladders positioned between the plate and the tension strip on opposite sides of the plate can be inflated by pumps to pivot the finger, with one of the bladders being inflated while the other is being deflated.

  18. Repair of webbed fingers - slideshow

    MedlinePlus

    ... gov/ency/presentations/100096.htm Repair of webbed fingers - series—Normal anatomy To use the sharing features ... Health Solutions, Ebix, Inc. Related MedlinePlus Health Topics Finger Injuries and Disorders A.D.A.M., Inc. ...

  19. Spiral viscous fingering.

    NASA Astrophysics Data System (ADS)

    Nagatsu, Yuichiro; Hayashi, Atsushi; Kato, Yoshihito; Tada, Yutaka

    2006-11-01

    When a less-viscous fluid displaces a more-viscous fluid in a radial Hele-Shaw cell, viscous fingering pattern is believed to develop in a radial direction. We performed experiments on viscous fingering in a radial Hele-Shaw cell when a polymer solution, a sodium polyacrylate (SPA) solution is used as the more-viscous fluid and the trivalent iron (Fe^3+) solution is as the less-viscous fluid. The experiment was done by varying the concentration of Fe^3+, cFe3+. We have found that viscous fingering pattern develops spirally when cFe3+ is larger than a threshold value, while the pattern develops in a radial direction for small cFe3+. We confirmed from different experiments that an instantaneous chemical reaction takes place between SPA solution and Fe^3+ solution. The chemical reaction produces precipitation and significantly reduces the viscosity of the SPA solution. The quantity of the precipitation is increased with cFe3+. We will make a discussion on the relationship between the formation of spiral viscous fingering and the chemical reaction taking place between the two fluids.

  20. Tension Distribution in a Tendon-Driven Robotic Finger

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)

    2013-01-01

    A method is provided for distributing tension among tendons of a tendon-driven finger in a robotic system, wherein the finger characterized by n degrees of freedom and n+1 tendons. The method includes determining a maximum functional tension and a minimum functional tension of each tendon of the finger, and then using a controller to distribute tension among the tendons, such that each tendon is assigned a tension value less than the maximum functional tension and greater than or equal to the minimum functional tension. The method satisfies the minimum functional tension while minimizing the internal tension in the robotic system, and satisfies the maximum functional tension without introducing a coupled disturbance to the joint torques. A robotic system includes a robot having at least one tendon-driven finger characterized by n degrees of freedom and n+1 tendons, and a controller having an algorithm for controlling the tendons as set forth above.

  1. Safe Finger Tourniquet--Ideas.

    PubMed

    Wei, Lin-Gwei; Chen, Chieh-Feng; Hwang, Chun-Yuan; Chang, Chiung-Wen; Chiu, Wen-Kuan; Li, Chun-Chang; Wang, Hsian-Jenn

    2016-03-01

    Tourniquets are often needed for optimized phalangeal surgeries. However, few surgeons forget to remove them and caused ischemic injuries. We have a modified method to create a safe finger tourniquet for short duration finger surgeries, which can avoid such tragedy. It is done by donning a glove, cutting the tip of the glove over the finger of interest, and rolling the glove finger to the base. From 2010 to 2013, approximately 54 patients underwent digital surgical procedures with our safe finger tourniquet. Because the glove cannot be forgotten to be removed, the tourniquet must be released and removed. This is a simple and efficient way to apply a safe finger tourniquet by using hand rubber glove for a short-term bloodless finger surgery and can achieve an excellent surgical result. PMID:26855166

  2. Finger stiffness or edema as presenting symptoms of eosinophilic fasciitis.

    PubMed

    Suzuki, Shingo; Noda, Kazutaka; Ohira, Yoshiyuki; Shikino, Kiyoshi; Ikusaka, Masatomi

    2015-10-01

    To investigate the clinical features and finger symptoms of eosinophilic fasciitis (EF), we reviewed five patients with EF. The chief complaint was pain, edema and/or stiffness of the extremities. The distal extremities were affected in all patients, and there was also proximal involvement in one patient. One patient had asymmetrical symptoms. All four patients with upper limb involvement had limited range of motion of the wrist joints, and three of them complained of finger symptoms. Two of these three patients showed slight non-pitting edema of the hands, and the other one had subcutaneous induration of the forearm. All four patients with lower limb symptoms had limited range of motion of the ankle joints, and two showed edema or induration of the legs. Inflammatory changes in the joints were not detected in any of the patients. Two patients displayed neither objective induration nor edema, and two patients had muscle tenderness. In conclusion, finger symptoms of patients with EF might be caused by fasciitis of the forearms, which leads to dysfunction of the long finger flexors and extensors as well as slight edema of hands. Limited range of motion of wrist and/or ankle joints indicates sensitively distal muscle dysfunction caused by fasciitis. PMID:26248532

  3. Virtual three-dimensional blackboard: three-dimensional finger tracking with a single camera

    NASA Astrophysics Data System (ADS)

    Wu, Andrew; Hassan-Shafique, Khurram; Shah, Mubarak; da Vitoria Lobo, N.

    2004-01-01

    We present a method for three-dimensional (3D) tracking of a human finger from a monocular sequence of images. To recover the third dimension from the two-dimensional images, we use the fact that the motion of the human arm is highly constrained owing to the dependencies between elbow and forearm and the physical constraints on joint angles. We use these anthropometric constraints to derive a 3D trajectory of a gesticulating arm. The system is fully automated and does not require human intervention. The system presented can be used as a visualization tool, as a user-input interface, or as part of some gesture-analysis system in which 3D information is important.

  4. Response to reflected-force feedback to fingers in teleoperations

    NASA Technical Reports Server (NTRS)

    Sutter, P. H.; Iatridis, J. C.; Thakor, N. V.

    1989-01-01

    Reflected-force feedback is an important aspect of teleoperations. The objective is to determine the ability of the human operator to respond to that force. Telerobotics operation is simulated by computer control of a motor-driven device with capabilities for programmable force feedback and force measurement. A computer-controlled motor drive is developed that provides forces against the fingers as well as (angular) position control. A load cell moves in a circular arc as it is pushed by a finger and measures reaction forces on the finger. The force exerted by the finger on the load cell and the angular position are digitized and recorded as a function of time by the computer. Flexure forces of the index, long and ring fingers of the human hand in opposition to the motor driven load cell are investigated. Results of the following experiments are presented: (1) Exertion of maximum finger force as a function of angle; (2) Exertion of target finger force against a computer controlled force; and (3) Test of the ability to move to a target force against a force that is a function of position. Averaged over ten individuals, the maximum force that could be exerted by the index or long finger is about 50 Newtons, while that of the ring finger is about 40 Newtons. From the tests of the ability of a subject to exert a target force, it was concluded that reflected-force feedback can be achieved with the direct kinesthetic perception of force without the use of tactile or visual clues.

  5. Joint contribution to fingertip movement during a number entry task: an application of Jacobian matrix.

    PubMed

    Qin, Jin; Trudeau, Matthieu; Buchholz, Bryan; Katz, Jeffrey N; Xu, Xu; Dennerlein, Jack T

    2014-04-01

    Upper extremity kinematics during keyboard use is associated with musculoskeletal health among computer users; however, specific kinematics patterns are unclear. This study aimed to determine the dynamic roles of the shoulder, elbow, wrist and metacarpophalangeal (MCP) joints during a number entry task. Six subjects typed in phone numbers using their right index finger on a stand-alone numeric keypad. The contribution of each joint of the upper extremity to the fingertip movement during the task was calculated from the joint angle trajectory and the Jacobian matrix of a nine-degree-of-freedom kinematic representation of the finger, hand, forearm and upper arm. The results indicated that in the vertical direction where the greatest fingertip movement occurred, the MCP, wrist, elbow (including forearm) and shoulder joint contributed 10.2%, 55.6%, 27.7% and 6.5%, respectively, to the downward motion of the index finger averaged across subjects. The results demonstrated that the wrist and elbow contribute the most to the fingertip vertical movement, indicating that they play a major role in the keying motion and have a dynamic load beyond maintaining posture. PMID:24144858

  6. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

  7. Finger Forces in Clarinet Playing

    PubMed Central

    Hofmann, Alex; Goebl, Werner

    2016-01-01

    Clarinettists close and open multiple tone holes to alter the pitch of the tones. Their fingering technique must be fast, precise, and coordinated with the tongue articulation. In this empirical study, finger force profiles and tongue techniques of clarinet students (N = 17) and professional clarinettists (N = 6) were investigated under controlled performance conditions. First, in an expressive-performance task, eight selected excerpts from the first Weber Concerto were performed. These excerpts were chosen to fit in a 2 × 2 × 2 design (register: low–high; tempo: slow–fast, dynamics: soft–loud). There was an additional condition controlled by the experimenter, which determined the expression levels (low–high) of the performers. Second, a technical-exercise task, an isochronous 23-tone melody was designed that required different effectors to produce the sequence (finger-only, tongue-only, combined tongue-finger actions). The melody was performed in three tempo conditions (slow, medium, fast) in a synchronization-continuation paradigm. Participants played on a sensor-equipped Viennese clarinet, which tracked finger forces and reed oscillations simultaneously. From the data, average finger force (Fmean) and peak force (Fmax) were calculated. The overall finger forces were low (Fmean = 1.17 N, Fmax = 3.05 N) compared to those on other musical instruments (e.g., guitar). Participants applied the largest finger forces during the high expression level performance conditions (Fmean = 1.21 N). For the technical exercise task, timing and articulation information were extracted from the reed signal. Here, the timing precision of the fingers deteriorated the timing precision of the tongue for combined tongue-finger actions, especially for faster tempi. Although individual finger force profiles were overlapping, the group of professional players applied less finger force overall (Fmean = 0.54 N). Such sensor instruments provide useful insights into player

  8. Gert Finger Becomes Emeritus Physicist

    NASA Astrophysics Data System (ADS)

    de Zeeuw, T.; Lucuix, C.; Péron, M.

    2016-03-01

    Gert Finger has retired after almost 33 years service and he has been made the first Emeritus Physicist at ESO. An appreciation of some of his many achievements in the development of infrared instrumentation and detector controllers is given. A retirement party for Gert Finger was held in February 2016.

  9. Connective tissue adaptations in the fingers of performance sport climbers.

    PubMed

    Schreiber, Tonja; Allenspach, Philippe; Seifert, Burkhardt; Schweizer, Andreas

    2015-01-01

    This study investigates the changes of the connective tissue in the fingers of performance sport climbers resulting after a minimum of 15 years of climbing. Evaluation was performed by ultrasonography on the palmar side of the fingers (Dig) II-V to measure the thickness of the A2 and A4 annular pulleys, the flexor digitorum superficialis (FDS) and profundus (FDP) tendons and the palmar plates (PP's) of the proximal interphalangeal (PIP) as well as distal interphalangeal (DIP) joint in sagittal and axial direction. Totally, 31 experienced male sport climbers (mean age 37y, 30-48y grade French scale median 8b, range 7b+ to 9a+) participated in the study. The control-group consisted of 20 male non-climbers (age 37y, 30-51y). The A2 and A4 pulleys in climbers were all significantly thicker (A2 Dig III 62%, Dig IV 69%; A4 Dig III 69%, Dig IV 76%) as compared to non-climbers pulleys. All PP's of the DIP joints were also significantly thicker, particularly at Dig III and IV (76 and 67%), whereas the PP's at PIP joints were only scarce significant for three joints. Differences of the diameter of the flexor tendons were less distinct (1-21%) being significant only over the middle phalanx. High load to the fingers of rock climbers after a minimum of 15 years of climbing years induced considerable connective tissue adaptions in the fingers, most distinct at the flexor tendon pulleys and joint capsule (PP) of the DIP joints and well detectable by ultrasound. PMID:26267120

  10. A new approach to depict bone surfaces in finger imaging using photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Biswas, S. K.; van Es, P.; Steenbergen, W.; Manohar, S.

    2015-03-01

    Imaging the vasculature close around the finger joints is of interest in the field of rheumatology. Locally increased vasculature in the synovial membrane of these joints can be a marker for rheumatoid arthritis. In previous work we showed that part of the photoacoustically induced ultrasound from the epidermis reflects on the bone surface within the finger. These reflected signals could be wrongly interpreted as new photoacoustic sources. In this work we show that a conventional ultrasound reconstruction algorithm, that considers the skin as a collection of ultrasound transmitters and the PA tomography probe as the detector array, can be used to delineate bone surfaces of a finger. This can in the future assist in the localization of the joint gaps. This can provide us with a landmark to localize the region of the inflamed synovial membrane. We test the approach on finger mimicking phantoms.

  11. Design of a Reconfigurable Robotic System for Flexoextension Fitted to Hand Fingers Size.

    PubMed

    Aguilar-Pereyra, J Felipe; Castillo-Castaneda, Eduardo

    2016-01-01

    Due to the growing demand for assistance in rehabilitation therapies for hand movements, a robotic system is proposed to mobilize the hand fingers in flexion and extension exercises. The robotic system is composed by four, type slider-crank, mechanisms that have the ability to fit the user fingers length from the index to the little finger, through the adjustment of only one link for each mechanism. The trajectory developed by each mechanism corresponds to the natural flexoextension path of each finger. The amplitude of the rotations for metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) varies from 0 to 90° and the distal interphalangeal joint (DIP) varies from 0 to 60°; the joint rotations are coordinated naturally. The four R-RRT mechanisms orientation allows a 15° abduction movement for index, ring, and little fingers. The kinematic analysis of this mechanism was developed in order to assure that the displacement speed and smooth acceleration into the desired range of motion and the simulation results are presented. The reconfiguration of mechanisms covers about 95% of hand sizes of a group of Mexican adult population. Maximum trajectory tracking error is less than 3% in full range of movement and it can be compensated by the additional rotation of finger joints without injury to the user. PMID:27524880

  12. Design of a Reconfigurable Robotic System for Flexoextension Fitted to Hand Fingers Size

    PubMed Central

    Castillo-Castaneda, Eduardo

    2016-01-01

    Due to the growing demand for assistance in rehabilitation therapies for hand movements, a robotic system is proposed to mobilize the hand fingers in flexion and extension exercises. The robotic system is composed by four, type slider-crank, mechanisms that have the ability to fit the user fingers length from the index to the little finger, through the adjustment of only one link for each mechanism. The trajectory developed by each mechanism corresponds to the natural flexoextension path of each finger. The amplitude of the rotations for metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) varies from 0 to 90° and the distal interphalangeal joint (DIP) varies from 0 to 60°; the joint rotations are coordinated naturally. The four R-RRT mechanisms orientation allows a 15° abduction movement for index, ring, and little fingers. The kinematic analysis of this mechanism was developed in order to assure that the displacement speed and smooth acceleration into the desired range of motion and the simulation results are presented. The reconfiguration of mechanisms covers about 95% of hand sizes of a group of Mexican adult population. Maximum trajectory tracking error is less than 3% in full range of movement and it can be compensated by the additional rotation of finger joints without injury to the user. PMID:27524880

  13. Biomechanical analysis of the human finger extensor mechanism during isometric pressing.

    PubMed

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  14. Biomechanical Analysis of the Human Finger Extensor Mechanism during Isometric Pressing

    PubMed Central

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  15. Fjords in viscous fingering: selection of width and opening scale

    SciTech Connect

    Mineev-weinstein, Mark; Ristroph, Leif; Thrasher, Matthew; Swinney, Harry

    2008-01-01

    Our experiments on viscous fingering of air into oil contained between closely spaced plates reveal two selection rules for the fjords of oil that separate fingers of air. (Fjords are the building blocks of solutions of the zero-surface-tension Laplacian growth equation.) Experiments in rectangular and circular geometries yield fjords with base widths {lambda}{sub c}/2, where {lambda}{sub c} is the most unstable wavelength from a linear stability analysis. Further, fjords open at an angle of 8.0{sup o}{+-}1.0{sup o}. These selection rules hold for a wide range of pumping rates and fjord lengths, widths, and directions.

  16. Effect of the Silver Content of SnAgCu Solder on the Interfacial Reaction and on the Reliability of Angle Joints Fabricated by Laser-Jet Soldering

    NASA Astrophysics Data System (ADS)

    Ji, Hongjun; Ma, Yuyou; Li, Mingyu; Wang, Chunqing

    2015-02-01

    The silver content of lead-free solders affects their microstructure, the interfacial reaction, and the performance of the joints in reliability tests. In this study, Sn3.0Ag0.5Cu (wt.%, SAC305) and Sn1.0Ag0.5Cu (wt.%, SAC105) solder balls of diameter 55 μm were reflowed on gold surface pads by laser-jet soldering. It was found that four types of layered intermetallic compound (IMC) were formed at the interfaces; these were Au5Sn/AuSn, AuSn, AuSn2, and AuSn4 from the pad side to the solder matrix. The Au5Sn/AuSn eutectic region, thickness 400 nm, formed because of the high cooling rate induced by the laser-jet soldering. During high-temperature storage tests, the silver became segregated at the interfaces between the Au-Sn IMC and the solder matrix, resulting in inhibition of IMC growth in SAC305 joints, the shear strengths of which were higher than those of SAC105 joints. In mechanical drop tests, however, percentage failure of the SAC305 joints was twice that of the SAC105 joints.

  17. Ball-joint grounding ring

    NASA Technical Reports Server (NTRS)

    Aperlo, P. J. A.; Buck, P. A.; Weldon, V. A.

    1981-01-01

    In ball and socket joint where electrical insulator such as polytetrafluoroethylene is used as line to minimize friction, good electrical contact across joint may be needed for lightning protection or to prevent static-charge build-up. Electrical contact is maintained by ring of spring-loaded fingers mounted in socket. It may be useful in industry for cranes, trailers, and other applications requiring ball and socket joint.

  18. Losing dexterity: patterns of impaired coordination of finger movements in musician’s dystonia

    PubMed Central

    Furuya, Shinichi; Tominaga, Kenta; Miyazaki, Fumio; Altenmüller, Eckart

    2015-01-01

    Extensive training can bring about highly-skilled action, but may also impair motor dexterity by producing involuntary movements and muscular cramping, as seen in focal dystonia (FD) and tremor. To elucidate the underlying neuroplastic mechanisms of FD, the present study addressed the organization of finger movements during piano performance in pianists suffering from the condition. Principal component (PC) analysis identified three patterns of fundamental joint coordination constituting finger movements in both patients and controls. The first two coordination patterns described less individuated movements between the “dystonic” finger and key-striking fingers for patients compared to controls. The third coordination pattern, representing the individuation of movements between the middle and ring fingers, was evident during a sequence of strikes with these fingers in controls, which was absent in the patients. Consequently, rhythmic variability of keystrokes was more pronounced during this sequence of strikes for the patients. A stepwise multiple-regression analysis further identified greater variability of keystrokes for individuals displaying less individuated movements between the affected and striking fingers. The findings suggest that FD alters dexterous joint coordination so as to lower independent control of finger movements, and thereby degrades fine motor control. PMID:26289433

  19. Hydrodynamic analysis of different finger positions in swimming: a computational fluid dynamics approach.

    PubMed

    Vilas-Boas, João Paulo; Ramos, Rui J; Fernandes, Ricardo J; Silva, António J; Rouboa, Abel I; Machado, Leandro; Barbosa, Tiago M; Marinho, Daniel A

    2015-02-01

    The aim of this research was to numerically clarify the effect of finger spreading and thumb abduction on the hydrodynamic force generated by the hand and forearm during swimming. A computational fluid dynamics (CFD) analysis of a realistic hand and forearm model obtained using a computer tomography scanner was conducted. A mean flow speed of 2 m · s(-1) was used to analyze the possible combinations of three finger positions (grouped, partially spread, totally spread), three thumb positions (adducted, partially abducted, totally abducted), three angles of attack (a = 0°, 45°, 90°), and four sweepback angles (y = 0°, 90°, 180°, 270°) to yield a total of 108 simulated situations. The values of the drag coefficient were observed to increase with the angle of attack for all sweepback angles and finger and thumb positions. For y = 0° and 180°, the model with the thumb adducted and with the little finger spread presented higher drag coefficient values for a = 45° and 90°. Lift coefficient values were observed to be very low at a = 0° and 90° for all of the sweepback angles and finger and thumb positions studied, although very similar values are obtained at a = 45°. For y = 0° and 180°, the effect of finger and thumb positions appears to be much most distinct, indicating that having the thumb slightly abducted and the fingers grouped is a preferable position at y = 180°, whereas at y = 0°, having the thumb adducted and fingers slightly spread yielded higher lift values. Results show that finger and thumb positioning in swimming is a determinant of the propulsive force produced during swimming; indeed, this force is dependent on the direction of the flow over the hand and forearm, which changes across the arm's stroke. PMID:25222969

  20. Simulation of light transport in arthritic- and non-arthritic human fingers

    NASA Astrophysics Data System (ADS)

    Milanic, Matija; Paluchowski, Lukasz A.; Randeberg, Lise L.

    2014-03-01

    Rheumatoid arthritis is a disease that frequently leads to joint destruction. It has high incidence rates worldwide, and the disease significantly reduces patient's quality of life due to pain, swelling and stiffness of the affected joints. Early diagnosis is necessary to improve course of the disease, therefore sensitive and accurate diagnostic tools are required. Optical imaging techniques have capability for early diagnosis and monitoring of arthritis. As compared to conventional diagnostic techniques optical technique is a noninvasive, noncontact and fast way of collecting diagnostic information. However, a realistic model of light transport in human joints is needed for understanding and developing of such optical diagnostic tools. The aim of this study is to develop a 3D numerical model of light transport in a human finger. The model will guide development of a hyperspectral imaging (HSI) diagnostic modality for arthritis in human fingers. The implemented human finger geometry is based on anatomical data. Optical data of finger tissues are adjusted to represent either an arthritic or an unaffected finger. The geometry and optical data serve as input into a 3D Monte Carlo method, which calculate diffuse reflectance, transmittance and absorbed energy distributions. The parameters of the model are optimized based on HIS-measurements of human fingers. The presented model serves as an important tool for understanding and development of HSI as an arthritis diagnostic modality. Yet, it can be applied to other optical techniques and finger diseases.

  1. Finger Tendon Travel Associated with Sequential Trigger Nail Gun Use

    PubMed Central

    Lowe, Brian; Albers, James; Hudock, Stephen; Krieg, Edward

    2015-01-01

    TECHNICAL ABSTRACT Background Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers have been shown to be a safer alternative to contact actuation triggers because they reduce traumatic injury risk. However, the sequential actuation trigger must be depressed for each individual nail fired as opposed to the contact actuation trigger, which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the sequential actuation trigger. Purpose This study developed a method to predict cumulative finger flexor tendon travel associated with the sequential actuation trigger nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood-frame construction tasks. Methods Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks–wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. Results Finger flexor tendon travel was attributable mostly to proximal interphalangeal and distal interphalangeal joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high-production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1700 trigger presses/day). Conclusion and Applications These results suggest that exposure to finger tendon travel from sequential actuation trigger nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk. PMID

  2. Fingering Instabilities in Dewetting Nanofluids

    NASA Astrophysics Data System (ADS)

    Pauliac-Vaujour, E.; Stannard, A.; Martin, C. P.; Blunt, M. O.; Notingher, I.; Moriarty, P. J.; Vancea, I.; Thiele, U.

    2008-05-01

    The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises from evaporatively driven nucleation and growth in a nanoscopically thin precursor solvent film behind the macroscopic contact line. We find that well-developed isotropic fingering structures only form for a narrow range of experimental parameters. Numerical simulations, based on a modification of the Monte Carlo approach introduced by Rabani et al. [Nature (London)NATUAS0028-0836 426, 271 (2003)10.1038/nature02087], reproduce the patterns we observe experimentally.

  3. Fingering instabilities in dewetting nanofluids.

    PubMed

    Pauliac-Vaujour, E; Stannard, A; Martin, C P; Blunt, M O; Notingher, I; Moriarty, P J; Vancea, I; Thiele, U

    2008-05-01

    The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises from evaporatively driven nucleation and growth in a nanoscopically thin precursor solvent film behind the macroscopic contact line. We find that well-developed isotropic fingering structures only form for a narrow range of experimental parameters. Numerical simulations, based on a modification of the Monte Carlo approach introduced by Rabani et al. [Nature (London) 426, 271 (2003)10.1038/nature02087], reproduce the patterns we observe experimentally. PMID:18518311

  4. Finger-Circumference-Measuring Device

    NASA Technical Reports Server (NTRS)

    Le, Suy

    1995-01-01

    Easy-to-use device quickly measures circumference of finger (including thumb) on human hand. Includes polytetrafluoroethylene band 1/8 in. wide, bent into loop and attached to tab that slides on scale graduated in millimeters. Sliding tab preloaded with constant-force tension spring, which pulls tab toward closure of loop. Designed to facilitate measurements at various points along fingers to obtain data for studies of volumetric changes of fingers in microgravity. Also used in normal Earth gravity studies of growth and in assessment of diseases like arthritis.

  5. Finger Forces in Clarinet Playing.

    PubMed

    Hofmann, Alex; Goebl, Werner

    2016-01-01

    Clarinettists close and open multiple tone holes to alter the pitch of the tones. Their fingering technique must be fast, precise, and coordinated with the tongue articulation. In this empirical study, finger force profiles and tongue techniques of clarinet students (N = 17) and professional clarinettists (N = 6) were investigated under controlled performance conditions. First, in an expressive-performance task, eight selected excerpts from the first Weber Concerto were performed. These excerpts were chosen to fit in a 2 × 2 × 2 design (register: low-high; tempo: slow-fast, dynamics: soft-loud). There was an additional condition controlled by the experimenter, which determined the expression levels (low-high) of the performers. Second, a technical-exercise task, an isochronous 23-tone melody was designed that required different effectors to produce the sequence (finger-only, tongue-only, combined tongue-finger actions). The melody was performed in three tempo conditions (slow, medium, fast) in a synchronization-continuation paradigm. Participants played on a sensor-equipped Viennese clarinet, which tracked finger forces and reed oscillations simultaneously. From the data, average finger force (F mean ) and peak force (F max ) were calculated. The overall finger forces were low (F mean = 1.17 N, F max = 3.05 N) compared to those on other musical instruments (e.g., guitar). Participants applied the largest finger forces during the high expression level performance conditions (F mean = 1.21 N). For the technical exercise task, timing and articulation information were extracted from the reed signal. Here, the timing precision of the fingers deteriorated the timing precision of the tongue for combined tongue-finger actions, especially for faster tempi. Although individual finger force profiles were overlapping, the group of professional players applied less finger force overall (F mean = 0.54 N). Such sensor instruments provide useful insights into player

  6. Review of Acute Traumatic Closed Mallet Finger Injuries in Adults

    PubMed Central

    Salazar Botero, Santiago; Hidalgo Diaz, Juan Jose; Benaïda, Anissa; Collon, Sylvie; Facca, Sybille

    2016-01-01

    In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana's classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning. PMID:27019806

  7. Cross Gradient Based Joint Inversion of 2D Wide Angle Seismic Reflection/Refraction and Gravity Data Along the Profile Through the 2010 Ms 7.1 Yushu Earthquake, China

    NASA Astrophysics Data System (ADS)

    Xiang, S.; Zhang, H.

    2015-12-01

    2D wide-angle seismic reflection/refraction survey has been widely used to investigate crustal structure and Moho topography. Similarly gravity survey is also very important in the study of local and regional earth features. Seismic survey is sensitive to the seismic velocity parameters and interface variations. For gravity survey, it is sensitive to density parameters of the medium but the resolution along the vertical direction is relatively poor. In this study, we have developed a strategy to jointly invert for seismic velocity model, density model and interface positions using the gravity observations and seismic arrival times from different phases. For the joint inversion of seismic and gravity data, it often relies on the empirical relationship between seismic velocity and density. In comparison, our joint inversion strategy also includes the cross-gradient based structure constraint for seismic velocity and density models in addition to the empirical relationship between them. The objective function for the joint inversion includes data misfit terms for seismic travel times and gravity observations, the cross-gradient constraint, the smoothness terms for two models, and the data misfit term between predicted gravity data based on density model converted from velocity model using the empirical relationship. Each term has its respective weight. We have applied the new joint inversion method to the Riwoqe-Yushu-Maduo profile in northwest China. The profile crosses through the Qiangtang block and Bayan Har block from southwest to northeast, respectively. The 2010 Ms 7.1 Yushu earthquake is located on the profile, around the Ganzi-Yushu fault zone. The joint inversion produces the velocity and density models that are similar in structure and at the same time fit their respective data sets well. Compared to separate seismic inversion using seismic travel times, the joint inversion with gravity data gives a velocity model that better delineates the fault zones. Low

  8. Improving the fatigue resistance of adhesive joints in laminated wood structures

    NASA Technical Reports Server (NTRS)

    Laufenberg, Theodore L.; River, Bryan H.; Murmanis, Lidija L.; Christiansen, Alfred W.

    1988-01-01

    The premature fatigue failure of a laminated wood/epoxy test beam containing a cross section finger joint was the subject of a multi-disciplinary investigation. The primary objectives were to identify the failure mechanisms which occurred during the finger joint test and to provide avenues for general improvements in the design and fabrication of adhesive joints in laminated wood structures.

  9. Neural correlates of finger gnosis.

    PubMed

    Rusconi, Elena; Tamè, Luigi; Furlan, Michele; Haggard, Patrick; Demarchi, Gianpaolo; Adriani, Michela; Ferrari, Paolo; Braun, Christoph; Schwarzbach, Jens

    2014-07-01

    Neuropsychological studies have described patients with a selective impairment of finger identification in association with posterior parietal lesions. However, evidence of the role of these areas in finger gnosis from studies of the healthy human brain is still scarce. Here we used functional magnetic resonance imaging to identify the brain network engaged in a novel finger gnosis task, the intermanual in-between task (IIBT), in healthy participants. Several brain regions exhibited a stronger blood oxygenation level-dependent (BOLD) response in IIBT than in a control task that did not explicitly rely on finger gnosis but used identical stimuli and motor responses as the IIBT. The IIBT involved stronger signal in the left inferior parietal lobule (IPL), bilateral precuneus (PCN), bilateral premotor cortex, and left inferior frontal gyrus. In all regions, stimulation of nonhomologous fingers of the two hands elicited higher BOLD signal than stimulation of homologous fingers. Only in the left anteromedial IPL (a-mIPL) and left PCN did signal strength decrease parametrically from nonhomology, through partial homology, to total homology with stimulation delivered synchronously to the two hands. With asynchronous stimulation, the signal was stronger in the left a-mIPL than in any other region, possibly indicating retention of task-relevant information. We suggest that the left PCN may contribute a supporting visuospatial representation via its functional connection to the right PCN. The a-mIPL may instead provide the core substrate of an explicit bilateral body structure representation for the fingers that when disrupted can produce the typical symptoms of finger agnosia. PMID:24990921

  10. Rehabilitation for bilateral amputation of fingers

    USGS Publications Warehouse

    Stapanian, Martin A.; Stapanian, Adrienne M.P.; Staley, Keith E.

    2010-01-01

    We describe reconstructive surgeries, therapy, prostheses, and adaptations for a patient who experienced bilateral amputation of all five fingers of both hands through the proximal phalanges in January 1992. The patient made considerable progress in the use of his hands in the 10 mo after amputation, including nearly a 120% increase in the active range of flexion of metacarpophalangeal joints. In late 1992 and early 1993, the patient had "on-top plasty" surgeries, in which the index finger remnants were transferred onto the thumb stumps, performed on both hands. The increased web space and functional pinch resulting from these procedures made many tasks much easier. The patient and occupational therapists set challenging goals at all times. Moreover, the patient was actively involved in the design and fabrication of all prostheses and adaptations or he developed them himself. Although he was discharged from occupational therapy in 1997, the patient continues to actively find new solutions for prehension and grip strength 18 yr after amputation.

  11. Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

    NASA Astrophysics Data System (ADS)

    Penta, Francesco; Rossi, Cesare; Savino, Sergio

    2016-06-01

    This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snapthrough and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.

  12. Single Degree-of-Freedom Exoskeleton Mechanism Design for Finger Rehabilitation

    PubMed Central

    Wolbrecht, Eric T.; Reinkensmeyer, David J.; Perez-Gracia, Alba

    2014-01-01

    This paper presents the kinematic design of a single degree-of-freedom exoskeleton mechanism: a planar eight-bar mechanism for finger curling. The mechanism is part of a finger-thumb robotic device for hand therapy that will allow users to practice key pinch grip and finger-thumb opposition, allowing discrete control inputs for playing notes on a musical gaming interface. This approach uses the mechanism to generate the desired grasping trajectory rather than actuating the joints of the fingers and thumb independently. In addition, the mechanism is confined to the back of the hand, so as to allow sensory input into the palm of the hand, minimal size and apparent inertia, and the possibility of placing multiple mechanisms side-by-side to allow control of individual fingers. PMID:22275628

  13. Systems for producing precise movements of a joint over a wide range of speeds and displacements for tests of a static-position sense.

    PubMed

    Clark, F J; Burgess, R C

    1987-03-01

    This report describes 3 types of apparatus that were used to produce precise movements of a joint over a wide range of speeds and angles. The designs feature an ability for ultra slow rotation of the joint (fractions of a degree per min) with a minimum of extraneous cues. Two designs use servo-controlled DC motors configured as velocity servos and a third design uses a galvanometer motor configured as a position servo. Originally designed for use with humans in studies of proprioception with the ankle and two joints of the index finger (the metacarpophalangeal joint and proximal interphalangeal joint), the apparatuses should be useful in a variety of applications where precise control of velocity and position is needed. PMID:3573811

  14. Multi-finger interaction during involuntary and voluntary single finger force changes

    PubMed Central

    Martin, J.R.; Zatsiorsky, V.M.; Latash, M.L.

    2011-01-01

    Two types of finger interaction are characterized by positive co-variation (enslaving) or negative co-variation (error compensation) of finger forces. Enslaving reflects mechanical and neural connections among fingers, while error compensation results from synergic control of fingers to stabilize their net output. Involuntary and voluntary force changes by a finger were used to explore these patterns. We hypothesized that synergic mechanisms will dominate during involuntary force changes, while enslaving will dominate during voluntary finger force changes. Subjects pressed with all four fingers to match a target force that was 10% of their maximum voluntary contraction (MVC). One of the fingers was unexpectedly raised 5.0 mm at a speed of 30.0 mm/s. During finger raising the subject was instructed “not to intervene voluntarily”. After the finger was passively lifted and a new steady-state achieved, subjects pressed down with the lifted finger, producing a pulse of force voluntarily. The data were analyzed in terms of finger forces and finger modes (hypothetical commands to fingers reflecting their intended involvement). The target finger showed an increase in force during both phases. In the involuntary phase, the target finger force changes ranged between 10.71 ± 1.89% MVC (I-finger) and 16.60 ± 2.26% MVC (L-finger). Generally, non-target fingers displayed a force decrease with a maximum amplitude of −1.49 ± 0.43% MVC (L-finger). Thus, during the involuntary phase, error compensation was observed – non-lifted fingers showed a decrease in force (as well as in mode magnitude). During the voluntary phase, enslaving was observed – non-target fingers showed an increase in force and only minor changes in mode magnitude. The average change in force of non-target fingers ranged from 21.83 ± 4.47% MVC for R-finger (M-finger task) to 0.71 ± 1.10 % MVC for L-finger (I-finger task). The average change in mode of non-target fingers was between −7.34 ± 19

  15. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1998-12-01

    Joints that exhibited tough fracture behavior were formed in a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure were proposed. Joints with a simple overlap geometry (only a few fingers) had to be very long in order to prevent brittle failure. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength, by changing the fiber coating, significantly increased matrix cracking and ultimate strength of the joints. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints should permit building of structures containing joints with only a minor reduction of design stresses.

  16. Prediction of Service Lives of Bridge Expansion Joints

    NASA Astrophysics Data System (ADS)

    Huang, Ying-Hua; Lin, Jing-Jhan

    2010-05-01

    This paper presents a service-life prediction model of expansion joints. Significant factors influencing the service lives of expansion joints were identified by statistical methods. Artificial neural network was implemented to establish the service-life prediction model of expansion joints. Taken finger plate joints for illustration, eight statistically significant factors influencing the service lives of finger plate joints are identified among twenty one factors studied. Through these eight factors, the service lives of expansion joints can be predicted by the established model. The training and testing errors indicate that the established artificial neural network model can provide accurate predictions which are essential information for maintenance strategies.

  17. [The mallet finger in children and adolescents].

    PubMed

    Schmidt, B; Weinberg, A; Friedrich, H

    2008-06-01

    The "mallet finger" in childhood and adolescence differs from the "mallet finger" in adults because of an open or gradually closing epiphysial plate. Thus, our results of conservative and operative treatment were evaluated particularly in consideration of an open growth plate. We analysed retrospectively the data of all patients who suffered a lesion at the extensor tendon insertion between 1996 and 2005 and were treated at our hospital. The coding was done according to age, sex, localisation, typing by Doyle, therapy and functional outcome. The typing by Doyle was extended through dividing type IV A into A1 (=Aitken I) and A2 (=Aitken II). Depending on extension deficits, the results were evaluated as very good (0 degrees ), medium (<15 degrees) and bad (>15 degrees). 76 patients, 45 boys and 31 girls aged 1 to 17 years (average age: 11.3) were studied. In consideration of the modified typing by Doyle, following distribution arose: type I (n=16), type II (n=14), type III (n=0), type IV A1 (n=17), type IV A2 (n=6), type IV B (n=21) and type IV C (n=2). A total of 50 patients was treated conservatively. Out of 26 operatively treated patients, 4 could be classified as type I, 12 as type II, 1 as type IV A1, 2 as type IV A2, 5 as type IV B, and 2 as type IV C. In 81.5 % of all patients no functional extension deficit was seen at the end of treatment; in patients treated conservatively, the percentage rate was 94 %. 6 patients, who were treated primarily operatively, showed poor functional outcome. 2 of these developed a suture track infection, in 2 cases chondral and osseous damage in the joint existed additionally, in one patient there was a comminuted fracture and in one patient a technical operative problem. Even in adolescence, conservative treatment of types I, IV A1 and A2, as well as IV B injuries is promising. A prerequisite is a consequent splint treatment and strict regular lateral X-ray control of the fracture fragment. At the beginning of treatment, we

  18. Giant cell tumours in fingers among the Inuit population in Greenland

    PubMed Central

    Duelund, Nick; Hougaard, Kjeld

    2016-01-01

    Objective Giant cell tumours (GCTs) of the tendon sheets in fingers are rare. We therefore find it of interest to report on 5 cases identified in the Inuit population in Greenland within 16 months prior to this study. Material and methods The Inuit account for 56,000 people of the total population in Greenland. From November 2010 to 16 months prior to this study, we diagnosed 5 cases (0.6% of all orthopaedic operations) with a GCT of the flexor tendon sheet of a finger. The patients were aged between 10 and 54 years, and 4 were women. All of them had noticed slow-growing tumours over 3 or more years and were referred for a suspected ganglion. Results In two cases, the tumour was located at the distal interphalangeal (DIP) joint in the thumb and in one case at the third finger. Two other patients had tumours at the metacarpophalangeal (MCP) joint of the third finger and the thumb, respectively; one of these two had a communicating tumour to the DIP joint. The last patient had two tumours on the same finger, one at the MCP joint and the other at the DIP joint. In one case, the tumour had also eroded the cortex of the first phalanx of the thumb, and the largest tumour measured 5 cm. Conclusion GCTs of the flexor tendon sheets in fingers are rare. It could be a coincidence that we have seen 5 cases within a short period of time. It is not possible to identify past cases through a register. A tumour in a finger is not the most common location for a ganglion, especially not at the DIP level. Therefore, a large tumour at this location is more likely to be a GCT. PMID:27052154

  19. Fluid mixing from viscous fingering.

    PubMed

    Jha, Birendra; Cueto-Felgueroso, Luis; Juanes, Ruben

    2011-05-13

    Mixing efficiency at low Reynolds numbers can be enhanced by exploiting hydrodynamic instabilities that induce heterogeneity and disorder in the flow. The unstable displacement of fluids with different viscosities, or viscous fingering, provides a powerful mechanism to increase fluid-fluid interfacial area and enhance mixing. Here we describe the dissipative structure of miscible viscous fingering, and propose a two-equation model for the scalar variance and its dissipation rate. Our analysis predicts the optimum range of viscosity contrasts that, for a given Péclet number, maximizes interfacial area and minimizes mixing time. In the spirit of turbulence modeling, the proposed two-equation model permits upscaling dissipation due to fingering at unresolved scales. PMID:21668165

  20. Implementation of Robot Finger Using Shape Memory Alloys and Electrical Motors

    NASA Astrophysics Data System (ADS)

    Terauchi, Mina; Zenba, Kota; Shimada, Akira

    This paper introduces a mechanical structure and control technique of a second robot finger as a system integration. The finger has been developed as element of a robot hand which has 20 joints and 16 degrees of freedom in order to express fingerspelling. The first joint of the finger is driven by small DC servo motor and the second and third joints are driven by shape-memory alloy (SMA) wires. The hand system consists of four parts of “hand mechanism”, “drive device”, “control unit” and “man-machine interface”. In order to implement cooperative smooth motions, the control system is designed based on experimental results related to system identification, and the position trajectory refernce is designed considering time delay on the SMA. Finally, we report the simulation and experimental control results to evaluate the presented system.

  1. Modification of the Internal Suture Technique for Mallet Finger

    PubMed Central

    Jiang, Bo; Wang, Peiji; Zhang, Yong; Zhao, Jiaju; Dong, Qirong

    2015-01-01

    Abstract This article describes a treatment of tendinous mallet finger deformities using a modified internal suture technique for the stable fixation of the terminal extensor tendon and bone. Between March 2011 and July 2013, 15 patients with mallet fingers who had been treated using this modification were included in this study. The patients included 10 men and 5 women with a mean age of 33 years (range, 19–50 years). Of these patients, 9 had chronic mallet fingers, 3 were unable to comply with a splinting regimen, and 3 had a history of unsuccessful splinting therapy. The mean time between the injury and surgery was 5.5 months (range, 1–15 months). We graded the results using Crawford criteria. The mean follow-up period was 12 months (range, 9–16 months). The mean final active range of motion of the distal interphalangeal joint flexion was 73° (range, 60°–90°). Based on Crawford evaluation criteria, 8 patients were graded as excellent, 6 were graded as good, and 1 was graded as fair. Apart from 2 documented mild nail deformities, no complications were encountered. This modified technique should be considered for the management of a tendinous mallet finger deformity when the internal suture technique is planned. PMID:25674757

  2. Rolling-Convolute Joint For Pressurized Glove

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Bassick, John W.

    1994-01-01

    Rolling-convolute metacarpal/finger joint enhances mobility and flexibility of pressurized glove. Intended for use in space suit to increase dexterity and decrease wearer's fatigue. Also useful in diving suits and other pressurized protective garments. Two ring elements plus bladder constitute rolling-convolute joint balancing torques caused by internal pressurization of glove. Provides comfortable grasp of various pieces of equipment.

  3. Long-finger pollicization for macrodactyly of the thumb and index finger.

    PubMed

    Donohue, Kenneth W; Zlotolow, Dan A; Kozin, Scott H

    2014-01-01

    Pollicization of the long finger is rarely performed, and previously described for treating traumatic thumb and index finger loss. Because the long finger lacks the independence of motion and muscular attachments of the index finger, pollicization of the long finger requires modifications of the technique. We present the case of a 3-year-old girl with progressive macrodactyly of the thumb and index finger associated with a lipofibromatous hamartoma of the median nerve. The involved digits were severely enlarged, stiff, and nonfunctional. The child was treated with first and second ray resection followed by long-finger pollicization. Surgical pearls and pitfalls are discussed. PMID:24919138

  4. What's Your Angle on Angles?

    ERIC Educational Resources Information Center

    Browning, Christine A.; Garza-Kling, Gina; Sundling, Elizabeth Hill

    2007-01-01

    Although the nature of the research varies, as do concepts of angle, research in general supports the supposition that angle is a complex idea, best understood from a variety of perspectives. In fact, the concept of angle tends to be threefold, consisting of: (1) the traditional, static notion of two rays meeting at a common vertex; (2) the idea…

  5. From viscous fingering to bulk elastic fingering in soft materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Mora, Serge; Dauchot, Olivier; Mahadevan, L.; Bouchaud, Elisabeth

    2014-03-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. It shares some similarities with the famous Saffman-Taylor instability, but a systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. We have also shown that in Maxwell viscoelastic fluids, one crosses over continuously from a viscous to an elastic fingering instability.

  6. Development of a finger biomechanical model and its considerations.

    PubMed

    Fok, Kim Seng; Chou, Siaw Meng

    2010-03-01

    The development of a biomechanical model for a human finger is faced with many challenges, such as extensor mechanism complexity, statistical indeterminacy and suitability of computational processes. Motivation for this work was to develop a computer model that is able to predict the internal loading patterns of tendons and joint surfaces experienced by the human finger, while mitigating these challenges. Proposed methodology was based on a non-linear optimising mathematical technique with a criterion of boundary conditions and equality equations, maximised against unknown parameters to reduce statistical indeterminacy. Initial validation was performed via the simulation of one dynamic and two static postures case studies. Past models and experiments were used, based on published literature, to verify the proposed model's methodology and results. The feasibility of the proposed methodology was deemed satisfactory as the simulated results were concordant with in-vivo results for the extrinsic flexors. PMID:19962148

  7. Surgical treatment of degenerative osteoarthritis of the fingers.

    PubMed

    Rongières, M

    2013-09-01

    Degenerative osteoarthritis of the long fingers is rare and surgical management is often necessary if there is joint pain, however this indication should not only be based on radiographic imaging. The specific anatomical problems of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are described. The surgical approach for each joint is described as well as functional management, in particular that of the extensor apparatus. Mobility should always be preserved for the MCP, arthroplasties are recommended for the PIP except for the index, and arthrodesis for the DIP. The different and most frequently used implants are described as well as the indications and expected results. The indications are discussed in relation to the limited results in the literature as well as the preferences of a panel of French hand surgeons. PMID:23684245

  8. Silicone Arthroplasty After Ankylosis of Proximal Interphalangeal Joints in Rheumatoid Arthritis: A Case Report.

    PubMed

    Awan, Hisham M; Imbriglia, Joseph E

    2016-01-01

    Rheumatoid arthritis (RA) can cause severe disability of the hand and fingers. Ankylosis of the finger joints is a known yet underreported manifestation of RA of the hand. We report the case of a patient who had RA and developed autofusion of the proximal interphalangeal (PIP) joints. At presentation, the PIP joints were fused in 15° of flexion. Silicone PIP arthroplasty was performed. Function improved with 60° of PIP joint motion and no pain. PMID:27327930

  9. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

    The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

  10. Optimize design dexterity of tooth-arrangement three-fingered hands

    NASA Astrophysics Data System (ADS)

    Wang, Hai-ying; Zhang, Li-yong; Zhang, Yong-de

    2005-12-01

    "Tooth-arrangement Three-fingered Hands" is a brand-new oral cavity repairing robot. It has the functions of fine grasping and arranging artificial tooth, manufacturing complete denture, etc. A new optimization design method is proposed in this paper that solves the problems in optimization structure parameter confirming and optimal dexterous design. The bionic theorem behind duplicating the dexterity of the human finger is incorporated into the structure parameter optimization algorithm. Through analyzing the dexterity of the single finger, adopting the design criteria of dexterous degree with optimum index and combining the characteristic of grasping the smallest object, this design method can confirm the best dexterity area for single finger, relations between every rod length and rotation range of every joint. Using MATLAB optimization toolbox to optimize above-mentioned structure parameter, it gains the optimal dimension that meets characteristic of human fingers and can finish grasping. A quantitative method is also proposed in this paper to calculate the relative position between fingers. It is applied to the real design of Tooth-Arrangement Three-fingered Hands and obtained optimal flexible performance.

  11. Evaluation of hydrodynamic scaling in porous media using finger dimensions

    NASA Astrophysics Data System (ADS)

    Selker, John S.; Schroth, Martin H.

    1998-08-01

    The use of dimensionless scaling is ubiquitous to hydrodynamic analysis, providing a powerful method of extending limited experimetnal results and generalizing theories. Miller and Miller [1956] contributed a scaling framework for immiscible fluid flow through porous media that relied on consistency of the contact angle between systems to be compared. It is common to assume that the effective contact angle will be zero in clean sand material where water is the wetting liquid. The well-documented unstable wetting process of fingered flow is used here as a diagnostic tool for the scaling relationships for infiltration into sandy media. Through comparison of finger cross sections produced using three liquids as well as various concentrations of anionic surfactant, it is shown that the zero contact angle assumption is very poor even for laboratory cleaned silica sand: Experimental results demonstrate effective contact angles approaching 60°. Scaling was effective for a given liquid between sands of differing particle size. These results suggest that caution should be exercised when applying scaling theory to initial wetting of porous media by liquids of differing gas-liquid interfacial tensions.

  12. Impact of Finger Type in Fingerprint Authentication

    NASA Astrophysics Data System (ADS)

    Gafurov, Davrondzhon; Bours, Patrick; Yang, Bian; Busch, Christoph

    Nowadays fingerprint verification system is the most widespread and accepted biometric technology that explores various features of the human fingers for this purpose. In general, every normal person has 10 fingers with different size. Although it is claimed that recognition performance with little fingers can be less accurate compared to other finger types, to our best knowledge, this has not been investigated yet. This paper presents our study on the topic of influence of the finger type into fingerprint recognition performance. For analysis we employ two fingerprint verification software packages (one public and one commercial). We conduct test on GUC100 multi sensor fingerprint database which contains fingerprint images of all 10 fingers from 100 subjects. Our analysis indeed confirms that performance with small fingers is less accurate than performance with the others fingers of the hand. It also appears that best performance is being obtained with thumb or index fingers. For example, performance deterioration from the best finger (i.e. index or thumb) to the worst fingers (i.e. small ones) can be in the range of 184%-1352%.

  13. Does finger sense predict addition performance?

    PubMed

    Newman, Sharlene D

    2016-05-01

    The impact of fingers on numerical and mathematical cognition has received a great deal of attention recently. However, the precise role that fingers play in numerical cognition is unknown. The current study explores the relationship between finger sense, arithmetic and general cognitive ability. Seventy-six children between the ages of 5 and 12 participated in the study. The results of stepwise multiple regression analyses demonstrated that while general cognitive ability including language processing was a predictor of addition performance, finger sense was not. The impact of age on the relationship between finger sense, and addition was further examined. The participants were separated into two groups based on age. The results showed that finger gnosia score impacted addition performance in the older group but not the younger group. These results appear to support the hypothesis that fingers provide a scaffold for calculation and that if that scaffold is not properly built, it has continued differential consequences to mathematical cognition. PMID:26993292

  14. Joint swelling

    MedlinePlus

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  15. Somatosensory evoked potentials following proprioceptive stimulation of finger in man.

    PubMed

    Mima, T; Terada, K; Maekawa, M; Nagamine, T; Ikeda, A; Shibasaki, H

    1996-09-01

    Brisk passive flexion of the proximal interphalangeal joint of the middle finger, produced by using a newly devised instrument, elicited evoked potentials on the scalp. The present study carefully excluded the possible contribution of sensory modalities other than proprioception. The initial part of cortical response was a positive deflexion at the contralateral central area (P1 at 34.6 ms after the stimulus). This was followed by a midfrontal negative wave (N1 at 44.8 ms) and a clear positivity at the contralateral centroparietal area (P2 at 48.0 ms). The evoked responses persisted in spite of the abolition of cutaneous and joint afferents of the finger caused by ischemic anesthesia, but they were lost by ischemic anesthesia of the forearm. Thus, the cortical evoked responses obtained in this study most probably reflect muscle afferent inputs. The scalp distribution of P1 suggested that its cortical generator source was different from that of the N20-P20 components of evoked potentials to electrical median nerve stimulation. Brodmann areas 2 and 3a of human brain, which are known to receive deep receptor inputs, are the most plausible generator sites for the early components of the proprioception-related evoked responses. The amplitude of P2 was related to the velocity but not to the magnitude of movement. In conclusion, the present study established a method for recording the evoked responses to the brisk passive movement of the finger joint, which mainly reflect the dynamic aspects of proprioception mediated through muscle afferent. PMID:8891653

  16. Swivel Joint For Liquid Nitrogen

    NASA Technical Reports Server (NTRS)

    Milner, James F.

    1988-01-01

    Swivel joint allows liquid-nitrogen pipe to rotate through angle of 100 degree with respect to mating pipe. Functions without cracking hard foam insulation on lines. Pipe joint rotates on disks so mechanical stress not transmitted to thick insulation on pipes. Inner disks ride on fixed outer disks. Disks help to seal pressurized liquid nitrogen flowing through joint.

  17. Double slotted socket spherical joint

    DOEpatents

    Bieg, Lothar F.; Benavides, Gilbert L.

    2001-05-22

    A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

  18. "Finger Kits:" An Interactive Demonstration of Biomaterials and Engineering for Elementary School Students

    ERIC Educational Resources Information Center

    Canavan, Heather E.; Stanton, Michael; Lopez, Kaori; Grubin, Catherine; Graham, Daniel J.

    2008-01-01

    This article describes a hands-on activity and demonstration developed at the University of Washington and further reined at the University of New Mexico. In this activity, the authors present a real-world problem to the student: Someone has an injured finger joint, and the students in the class need to design an implant to replace it. After…

  19. Current status of ultrasonography of the finger

    PubMed Central

    2016-01-01

    The recent development of advanced high-resolution transducers has enabled the fast, easy, and dynamic ultrasonographic evaluation of small, superficial structures such as the finger. In order to best exploit these advances, it is important to understand the normal anatomy and the basic pathologies of the finger, as exemplified by the following conditions involving the dorsal, volar, and lateral sections of the finger: sagittal band injuries, mallet finger, and Boutonnière deformity (dorsal aspect); flexor tendon tears, trigger finger, and volar plate injuries (volar aspect); gamekeeper’s thumb (Stener lesions) and other collateral ligament tears (lateral aspect); and other lesions. This review provides a basis for understanding the ultrasonography of the finger and will therefore be useful for radiologists. PMID:26753604

  20. On the fly finger knuckle print authentication

    NASA Astrophysics Data System (ADS)

    Abe, Narishige; Shinzaki, Takashi

    2014-05-01

    Finger knuckle print authentication has been researched not only as a supplemental authentication modality to fingerprint recognition but also as a method for logging into a PC or entering a building. However, in previous works, some specific devices were necessary to capture a finger knuckle print and users had to keep their fingers perfectly still to capture their finger knuckle. In this paper, we propose a new on the fly finger knuckle print authentication system using a general web camera. In our proposed authentication system, users can input their finger knuckle prints without needing their hand to remain motionless during image capture. We also evaluate the authentication accuracy of the proposed system, achieving an 7% EER under best conditions.

  1. Piezoelectric Actuators On A Cold Finger

    NASA Technical Reports Server (NTRS)

    Kuo, Chin-Po; Garba, John A.; Glaser, Robert J.

    1995-01-01

    Developmental system for active suppression of vibrations of cold finger includes three piezoelectric actuators bonded to outer surface. Actuators used to suppress longitudinal and lateral vibrations of upper end of cold finger by applying opposing vibrations. Cold finger in question is part of a cryogenic system associated with an infrared imaging detector. When fully developed, system would be feedback sensor/control/actuator system automatically adapting to changing vibrational environment and suppresses pressure-induced vibrations by imposing compensatory vibrations via actuators.

  2. Prosthetic Hand With Two Gripping Fingers

    NASA Technical Reports Server (NTRS)

    Norton, William E.; Belcher, Jewell B.; Vest, Thomas W.; Carden, James R.

    1993-01-01

    Prosthetic hand developed for amputee who retains significant portion of forearm. Outer end of device is end effector including two fingers, one moved by rotating remaining part of forearm about its longitudinal axis. Main body of end effector is end member supporting fingers, roller bearing assembly, and rack-and-pinion mechanism. Advantage of rack-and-pinion mechanism enables user to open or close gap between fingers with precision and force.

  3. Use of preputial skin for coverage of post-burn contractures of fingers in children

    PubMed Central

    Zaroo, Mohammed I.; Sheikh, Bashir A.; Wani, Adil H.; Darzi, Mohammad A.; Mir, Mohsin; Dar, Hameedullah; Baba Peerzada, U. F.; Zargar, Haroon R.

    2011-01-01

    Objective: Hand burns are common injuries. Children frequently sustain burn injuries, especially to their hands. Contractures are a common sequel of severe burns around joints. The prepuce, or foreskin, has been used as a skin graft for a number of indications. We conducted this study to evaluate the feasibility of utilising the preputial skin for the management of post-burn contractures of fingers in uncircumcised male children. Materials and Methods: Preputial skin was used for the coverage of released contractures of fingers in 12 patients aged 2-6 years. The aetiology of burns was “Kangri” burn in eight patients and scalding in four patients. Six patients had contracture in two fingers, four patients in one finger, and two patients had contractures in three fingers. Results: None of the patients had graft loss, and all the wounds healed within 2 weeks. All patients had complete release of contractures without any recurrence. Hyperpigmentation of the grafts was observed over a period of time, which was well accepted by the parents. Conclusions: Preputial skin can be used successfully for male children with mild-to-moderate contractures of 2-3 fingers for restoration of the hand function, minimal donor site morbidity. PMID:21713163

  4. The tendon network of the fingers performs anatomical computation at a macroscopic scale.

    PubMed

    Valero-Cuevas, Francisco J; Yi, Jae-Woong; Brown, Daniel; McNamara, Robert V; Paul, Chandana; Lipson, Hood

    2007-06-01

    Current thinking attributes information processing for neuromuscular control exclusively to the nervous system. Our cadaveric experiments and computer simulations show, however, that the tendon network of the fingers performs logic computation to preferentially change torque production capabilities. How this tendon network propagates tension to enable manipulation has been debated since the time of Vesalius and DaVinci and remains an unanswered question. We systematically changed the proportion of tension to the tendons of the extensor digitorum versus the two dorsal interosseous muscles of two cadaver fingers and measured the tension delivered to the proximal and distal interphalangeal joints. We find that the distribution of input tensions in the tendon network itself regulates how tensions propagate to the finger joints, acting like the switching function of a logic gate that nonlinearly enables different torque production capabilities. Computer modeling reveals that the deformable structure of the tendon networks is responsible for this phenomenon; and that this switching behavior is an effective evolutionary solution permitting a rich repertoire of finger joint actuation not possible with simpler tendon paths. We conclude that the structural complexity of this tendon network, traditionally oversimplified or ignored, may in fact be critical to understanding brain-body coevolution and neuromuscular control. Moreover, this form of information processing at the macroscopic scale is a new instance of the emerging principle of nonneural "somatic logic" found to perform logic computation such as in cellular networks. PMID:17549909

  5. Biased wrist and finger coordination in Parkinsonian patients during performance of graphical tasks.

    PubMed

    Dounskaia, Natalia; Van Gemmert, Arend W A; Leis, Berta C; Stelmach, George E

    2009-10-01

    Handwriting impairments in Parkinson's disease (PD) have been associated with micrographia, i.e. diminished letter size. However, dyscoordination of the wrist and fingers may also contribute to handwriting deterioration in PD. To investigate this hypothesis, right-handed PD patients and controls were tested in performance of three types of cyclic wrist and finger movements: drawing of two lines and a circle. The line drawing was performed with either simultaneous flexion and extension of the wrist and fingers (equivalent pattern resulting in a right-tilted line) or with wrist flexion/extension accompanied with finger extension/flexion (nonequivalent pattern resulting in a left-tilted line). Circle drawing required a specific phase difference between wrist and finger motions. Movements were performed with an inkless pen on a digitizer-tablet at two frequency levels. Consistent deformations of the circle into right-tilted ovals and lower variability in equivalent compared with nonequivalent lines revealed preference to produce right-tilted shapes. This preference became more apparent with increased movement speed and it was amplified in PD patients. Analysis revealed that the circle deformation emerged mainly due to reduction in relative phase, while wrist and finger amplitudes remained unchanged. The results suggest that PD causes deficit characterized by strong tendency to produce certain coordination patterns between wrist and finger motions. This deficit may significantly contribute to handwriting impairments in PD by reducing the dexterity in the production of the variety of shapes of the cursive letters. Furthermore, the deficiency revealed in wrist and finger coordination may represent a more general deficit affecting control of various multi-joint movements in PD. PMID:19410590

  6. Error compensation during finger force production after one- and four-finger voluntarily fatiguing exercise.

    PubMed

    Kruger, Eric S; Hoopes, Josh A; Cordial, Rory J; Li, Sheng

    2007-08-01

    The effect of muscle fatigue on error compensation strategies during multi-finger ramp force production tasks was investigated. Thirteen young, healthy subjects were instructed to produce a total force with four fingers of the right hand to accurately match a visually displayed template. The template consisted of a 3-s waiting period, a 3-s ramp force production [from 0 to 30% maximal voluntary contraction (MVC)], and a 3-s constant force production. A series of 12 ramp trials was performed before and after fatigue. Fatigue was induced by a 60-s maximal isometric force production with either the index-finger only or with all four fingers during two separate testing sessions. The average percent of drop was 38.2% in the MVC of the index finger after index-finger fatiguing exercise and 38.3% in the MVC of all fingers after four-finger fatiguing exercise. The ability of individual fingers to compensate for each other's errors in order for the total force to match the preset template was quantified as the error compensation index (ECI), i.e., the ratio of the sum of variances of individual finger forces and the variance of the total force. By comparing pre- and post-fatigue performance during four-finger ramp force production, we observed that the variance of the total force was not significantly changed after one- or four-finger fatiguing exercise. The ECI significantly decreased after four-finger fatiguing exercise, especially during the last second of the ramp; while the ECI remained unchanged after index finger single-finger fatiguing exercise. These results suggest that the central nervous system is able to utilize the abundant degrees of freedom to compensate for partial impairment of the motor apparatus induced by muscle fatigue to maintain the desired performance. However, this ability is significantly decreased when all elements of the motor apparatus are impaired. PMID:17443316

  7. Current concepts in the evaluation and treatment of mallet finger injury.

    PubMed

    Bloom, Jacob M P; Khouri, Joseph S; Hammert, Warren C

    2013-10-01

    The mallet finger is a frequently encountered fingertip injury that leads to extensor lag of the distal phalanx. Classification systems stratify these injuries as ranging from soft-tissue disruption of the extensor mechanism alone to those that have articular involvement and volar subluxation. The management of mallet finger injuries varies based on injury pattern and surgeon preference. These treatment options include splinting regimens, closed reduction and percutaneous pinning, and open reduction and internal fixation. Although the final goal of treatment is to establish a congruent joint, the efficacy of each treatment modality has been shown to vary. PMID:24076703

  8. Creating Number Semantics through Finger Movement Perception

    ERIC Educational Resources Information Center

    Badets, Arnaud; Pesenti, Mauro

    2010-01-01

    Communication, language and conceptual knowledge related to concrete objects may rely on the sensory-motor systems from which they emerge. How abstract concepts can emerge from these systems is however still unknown. Here we report a functional interaction between a specific meaningful finger movement, such as a finger grip closing, and a concept…

  9. Prevalence of self-reported finger deformations and occupational risk factors among professional cooks: a cross-sectional study

    PubMed Central

    2011-01-01

    Background Previous studies have pointed out that the school lunch workers in Japan are suffering from work-related disorders including finger deformations. The purpose of this study was to investigate the prevalence of self-reported finger deformations and the association with job-related risk factors. Methods A cross-sectional questionnaire study of 5,719 subjects (response rate: 81%, 982 men and 4,737 women) was undertaken during September 2003 to February 2004. Results Finger deformations were found among 11.7% of the men and 35.6% of the women studied, with significant differences among sex, age and sex-age groups. For both men and women the pattern of finger deformations across the hand was similar for the right and the left hand. For women, the deformations were found in about 10% of the distal interphalangeal joints of all fingers. Based on multiple logistic regression analyses, the factors female sex, age, the number of cooked lunches per cook and cooking activities were independently associated with the prevalence of finger deformations. High prevalence odds ratios were found for those frequently carrying or using tools by hands such as delivering containers, distributing meals, preparing dishes, washing equipment, cutting and stirring foods. Conclusions Among the school lunch workers studied, women had a higher prevalence of finger deformations on all joints of both hands. Various cooking tasks were associated with the prevalence of finger deformations. The results suggest that improvements in working conditions are important for preventing work-related disorders such as finger deformations. PMID:21615914

  10. Analysis and treatment of finger sucking.

    PubMed Central

    Ellingson, S A; Miltenberger, R G; Stricker, J M; Garlinghouse, M A; Roberts, J; Galensky, T L; Rapp, J T

    2000-01-01

    We analyzed and treated the finger sucking of 2 developmentally typical children aged 7 and 10 years. The functional analysis revealed that the finger sucking of both children was exhibited primarily during alone conditions, suggesting that the behavior was maintained by automatic reinforcement. An extended analysis provided support for this hypothesis and demonstrated that attenuation of stimulation produced by the finger sucking resulted in behavior reductions for both children. Treatment consisted of having each child wear a glove on the relevant hand during periods when he or she was alone. Use of the glove produced zero levels of finger sucking for 1 participant, whereas only moderate reductions were obtained for the other. Subsequently, an awareness enhancement device was used that produced an immediate reduction in finger sucking. PMID:10738951

  11. Jointed Holder For Welding Electrodes

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.

    1991-01-01

    Adjustable-angle holder enables use of standard straight electrode with custom-fabricated bent gas cup for welding in difficult-to-reach places. Electrode replaced easily, without removing cup, with aid of tool loosening miniature collet nut on holder. Consumes fewer electrodes for given amount of welding. Angle of holder continuously adjustable to fit angle of gas cup or geometry of part welded. Holder made double-jointed to accommodate gas cup having compound angles.

  12. Fingering in Stochastic Growth Models

    PubMed Central

    Aristotelous, Andreas C.; Durrett, Richard

    2015-01-01

    Motivated by the widespread use of hybrid-discrete cellular automata in modeling cancer, two simple growth models are studied on the two dimensional lattice that incorporate a nutrient, assumed to be oxygen. In the first model the oxygen concentration u(x, t) is computed based on the geometry of the growing blob, while in the second one u(x, t) satisfies a reaction-diffusion equation. A threshold θ value exists such that cells give birth at rate β(u(x, t) − θ)+ and die at rate δ(θ − u(x, t)+. In the first model, a phase transition was found between growth as a solid blob and “fingering” at a threshold θc = 0.5, while in the second case fingering always occurs, i.e., θc = 0. PMID:26430353

  13. Differing Dynamics of Intrapersonal and Interpersonal Coordination: Two-finger and Four-Finger Tapping Experiments

    PubMed Central

    Kodama, Kentaro; Furuyama, Nobuhiro; Inamura, Tetsunari

    2015-01-01

    Finger-tapping experiments were conducted to examine whether the dynamics of intrapersonal and interpersonal coordination systems can be described equally by the Haken—Kelso—Bunz model, which describes inter-limb coordination dynamics. This article reports the results of finger-tapping experiments conducted in both systems. Two within-subject factors were investigated: the phase mode and the number of fingers. In the intrapersonal experiment (Experiment 1), the participants were asked to tap, paced by a gradually hastening auditory metronome, looking at their fingers moving, using the index finger in the two finger condition, or the index and middle finger in the four-finger condition. In the interpersonal experiment (Experiment 2), pairs of participants performed the task while each participant used the outside hand, tapping with the index finger in the two finger condition, or the index and middle finger in the four-finger condition. Some results did not agree with the HKB model predictions. First, from Experiment 1, no significant difference was observed in the movement stability between the in-phase and anti-phase modes in the two finger condition. Second, from Experiment 2, no significant difference was found in the movement stability between the in-phase and anti-phase mode in the four-finger condition. From these findings, different coordination dynamics were inferred between intrapersonal and interpersonal coordination systems against prediction from the previous studies. Results were discussed according to differences between intrapersonal and interpersonal coordination systems in the availability of perceptual information and the complexity in the interaction between limbs derived from a nested structure. PMID:26070119

  14. State-based decoding of hand and finger kinematics using neuronal ensemble and LFP activity during dexterous reach-to-grasp movements

    PubMed Central

    Mollazadeh, Mohsen; Davidson, Adam G.; Schieber, Marc H.; Thakor, Nitish V.

    2013-01-01

    The performance of brain-machine interfaces (BMIs) that continuously control upper limb neuroprostheses may benefit from distinguishing periods of posture and movement so as to prevent inappropriate movement of the prosthesis. Few studies, however, have investigated how decoding behavioral states and detecting the transitions between posture and movement could be used autonomously to trigger a kinematic decoder. We recorded simultaneous neuronal ensemble and local field potential (LFP) activity from microelectrode arrays in primary motor cortex (M1) and dorsal (PMd) and ventral (PMv) premotor areas of two male rhesus monkeys performing a center-out reach-and-grasp task, while upper limb kinematics were tracked with a motion capture system with markers on the dorsal aspect of the forearm, hand, and fingers. A state decoder was trained to distinguish four behavioral states (baseline, reaction, movement, hold), while a kinematic decoder was trained to continuously decode hand end point position and 18 joint angles of the wrist and fingers. LFP amplitude most accurately predicted transition into the reaction (62%) and movement (73%) states, while spikes most accurately decoded arm, hand, and finger kinematics during movement. Using an LFP-based state decoder to trigger a spike-based kinematic decoder [r = 0.72, root mean squared error (RMSE) = 0.15] significantly improved decoding of reach-to-grasp movements from baseline to final hold, compared with either a spike-based state decoder combined with a spike-based kinematic decoder (r = 0.70, RMSE = 0.17) or a spike-based kinematic decoder alone (r = 0.67, RMSE = 0.17). Combining LFP-based state decoding with spike-based kinematic decoding may be a valuable step toward the realization of BMI control of a multifingered neuroprosthesis performing dexterous manipulation. PMID:23536714

  15. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, Eduardo V.

    1997-01-01

    A method for detecting wear in a battery tester probe. The method includes providing a battery tester unit having at least one tester finger, generating a tester signal using the tester fingers and battery tester unit with the signal characteristic of the electrochemical condition of the battery and the tester finger, applying wavelet transformation to the tester signal including computing a mother wavelet to produce finger wear indicator signals, analyzing the signals to create a finger wear index, comparing the wear index for the tester finger with the index for a new tester finger and generating a tester finger signal change signal to indicate achieving a threshold wear change.

  16. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, E.V.

    1997-11-18

    A method is described for detecting wear in a battery tester probe. The method includes providing a battery tester unit having at least one tester finger, generating a tester signal using the tester fingers and battery tester unit with the signal characteristic of the electrochemical condition of the battery and the tester finger, applying wavelet transformation to the tester signal including computing a mother wavelet to produce finger wear indicator signals, analyzing the signals to create a finger wear index, comparing the wear index for the tester finger with the index for a new tester finger and generating a tester finger signal change signal to indicate achieving a threshold wear change. 9 figs.

  17. Angle detector

    NASA Technical Reports Server (NTRS)

    Parra, G. T. (Inventor)

    1978-01-01

    An angle detector for determining a transducer's angular disposition to a capacitive pickup element is described. The transducer comprises a pendulum mounted inductive element moving past the capacitive pickup element. The capacitive pickup element divides the inductive element into two parts L sub 1 and L sub 2 which form the arms of one side of an a-c bridge. Two networks R sub 1 and R sub 2 having a plurality of binary weighted resistors and an equal number of digitally controlled switches for removing resistors from the networks form the arms of the other side of the a-c bridge. A binary counter, controlled by a phase detector, balances the bridge by adjusting the resistance of R sub 1 and R sub 2. The binary output of the counter is representative of the angle.

  18. Trigger finger, tendinosis, and intratendinous gene expression.

    PubMed

    Lundin, A-C; Aspenberg, P; Eliasson, P

    2014-04-01

    The pathogenesis of trigger finger has generally been ascribed to primary changes in the first annular ligament. In contrast, we recently found histological changes in the tendons, similar to the findings in Achilles tendinosis or tendinopathy. We therefore hypothesized that trigger finger tendons would show differences in gene expression in comparison to normal tendons in a pattern similar to what is published for Achilles tendinosis. We performed quantitative real-time polymerase chain reaction on biopsies from finger flexor tendons, 13 trigger fingers and 13 apparently healthy control tendons, to assess the expression of 10 genes which have been described to be differently expressed in tendinosis (collagen type 1a1, collagen 3a1, MMP-2, MMP-3, ADAMTS-5, TIMP-3, aggrecan, biglycan, decorin, and versican). In trigger finger tendons, collagen types 1a1 and 3a1, aggrecan and biglycan were all up-regulated, and MMP-3and TIMP-3 were down-regulated. These changes were statistically significant and have been previously described for Achilles tendinosis. The remaining four genes were not significantly altered. The changes in gene expression support the hypothesis that trigger finger is a form of tendinosis. Because trigger finger is a common condition, often treated surgically, it could provide opportunities for clinical research on tendinosis. PMID:22882155

  19. Finger muscle attachments for an OpenSim upper-extremity model.

    PubMed

    Lee, Jong Hwa; Asakawa, Deanna S; Dennerlein, Jack T; Jindrich, Devin L

    2015-01-01

    We determined muscle attachment points for the index, middle, ring and little fingers in an OpenSim upper-extremity model. Attachment points were selected to match both experimentally measured locations and mechanical function (moment arms). Although experimental measurements of finger muscle attachments have been made, models differ from specimens in many respects such as bone segment ratio, joint kinematics and coordinate system. Likewise, moment arms are not available for all intrinsic finger muscles. Therefore, it was necessary to scale and translate muscle attachments from one experimental or model environment to another while preserving mechanical function. We used a two-step process. First, we estimated muscle function by calculating moment arms for all intrinsic and extrinsic muscles using the partial velocity method. Second, optimization using Simulated Annealing and Hooke-Jeeves algorithms found muscle-tendon paths that minimized root mean square (RMS) differences between experimental and modeled moment arms. The partial velocity method resulted in variance accounted for (VAF) between measured and calculated moment arms of 75.5% on average (range from 48.5% to 99.5%) for intrinsic and extrinsic index finger muscles where measured data were available. RMS error between experimental and optimized values was within one standard deviation (S.D) of measured moment arm (mean RMS error = 1.5 mm < measured S.D = 2.5 mm). Validation of both steps of the technique allowed for estimation of muscle attachment points for muscles whose moment arms have not been measured. Differences between modeled and experimentally measured muscle attachments, averaged over all finger joints, were less than 4.9 mm (within 7.1% of the average length of the muscle-tendon paths). The resulting non-proprietary musculoskeletal model of the human fingers could be useful for many applications, including better understanding of complex multi-touch and gestural movements. PMID:25853869

  20. Finger Muscle Attachments for an OpenSim Upper-Extremity Model

    PubMed Central

    Lee, Jong Hwa; Asakawa, Deanna S.; Dennerlein, Jack T.; Jindrich, Devin L.

    2015-01-01

    We determined muscle attachment points for the index, middle, ring and little fingers in an OpenSim upper-extremity model. Attachment points were selected to match both experimentally measured locations and mechanical function (moment arms). Although experimental measurements of finger muscle attachments have been made, models differ from specimens in many respects such as bone segment ratio, joint kinematics and coordinate system. Likewise, moment arms are not available for all intrinsic finger muscles. Therefore, it was necessary to scale and translate muscle attachments from one experimental or model environment to another while preserving mechanical function. We used a two-step process. First, we estimated muscle function by calculating moment arms for all intrinsic and extrinsic muscles using the partial velocity method. Second, optimization using Simulated Annealing and Hooke-Jeeves algorithms found muscle-tendon paths that minimized root mean square (RMS) differences between experimental and modeled moment arms. The partial velocity method resulted in variance accounted for (VAF) between measured and calculated moment arms of 75.5% on average (range from 48.5% to 99.5%) for intrinsic and extrinsic index finger muscles where measured data were available. RMS error between experimental and optimized values was within one standard deviation (S.D) of measured moment arm (mean RMS error = 1.5 mm < measured S.D = 2.5 mm). Validation of both steps of the technique allowed for estimation of muscle attachment points for muscles whose moment arms have not been measured. Differences between modeled and experimentally measured muscle attachments, averaged over all finger joints, were less than 4.9 mm (within 7.1% of the average length of the muscle-tendon paths). The resulting non-proprietary musculoskeletal model of the human fingers could be useful for many applications, including better understanding of complex multi-touch and gestural movements. PMID:25853869

  1. Fingered core structure of nematic boojums

    NASA Astrophysics Data System (ADS)

    Kralj, Samo; Rosso, Riccardo; Virga, Epifanio G.

    2008-09-01

    Using the Landau-de Gennes phenomenological approach, we study the fine biaxial core structure of a boojum residing on the surface of a nematic liquid crystal phase. The core is formed by a negatively uniaxial finger, surrounded by a shell with maximal biaxiality. The characteristic finger’s length and the shell’s width are comparable to the biaxial correlation length. The finger tip is melted for topological reasons. Upon decreasing the surface anchoring strength below a critical value, the finger gradually leaves the bulk and it is expelled through the surface.

  2. Surgical Repair with External Fixation of Epiphyseal Fractures of the Proximal Phalanges of Three Fingers: A Case Report.

    PubMed

    Morisawa, Yasushi; Takayama, Shinichiro; Sato, Kazuki

    2015-10-01

    A 13-year-old girl sustained epiphyseal fractures of the proximal phalanges of the left index, middle, and ring fingers. Though manual reduction of the 3 fingers was possible, it was difficult to maintain the reduction due to severe instability of the middle and ring fingers, and closed reduction with external fixation was performed. At 4 years post-injury, the patient had no impairment of daily activities. The use of external fixation (1) causes no injury to the epiphyseal cartilage, (2) enables accurate reduction and maintenance of reduction, (3) is technically easier than pinning, (4) enables earlier range of motion (ROM) exercises of the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the externally fixated and other fingers, and (5) allows repeated fine adjustments after reduction. External fixation is an option for the treatment of children with highly unstable epiphyseal fractures of the proximal phalanges. PMID:26388013

  3. Patient-Specific Prosthetic Fingers by Remote Collaboration–A Case Study

    PubMed Central

    Cabibihan, John-John

    2011-01-01

    The concealment of amputation through prosthesis usage can shield an amputee from social stigma and help improve the emotional healing process especially at the early stages of hand or finger loss. However, the traditional techniques in prosthesis fabrication defy this as the patients need numerous visits to the clinics for measurements, fitting and follow-ups. This paper presents a method for constructing a prosthetic finger through online collaboration with the designer. The main input from the amputee comes from the Computer Tomography (CT) data in the region of the affected and the non-affected fingers. These data are sent over the internet and the prosthesis is constructed using visualization, computer-aided design and manufacturing tools. The finished product is then shipped to the patient. A case study with a single patient having an amputated ring finger at the proximal interphalangeal joint shows that the proposed method has a potential to address the patient's psychosocial concerns and minimize the exposure of the finger loss to the public. PMID:21573246

  4. Aesthetic finger prosthesis with silicone biomaterial

    PubMed Central

    Raghu, K M; Gururaju, C R; Sundaresh, K J; Mallikarjuna, Rachappa

    2013-01-01

    The fabrication of finger prosthesis is as much an art as it is science. The ideally constructed prosthesis must duplicate the missing structures so precisely that patients can appear in public without fear of attracting unwanted attraction. A 65-years-old patient reported with loss of his right index finger up to the second phalanx and wanted to get it replaced. An impression of the amputated finger and donor were made. A wax pattern of the prosthesis was fabricated using the donor impression; a trial was performed and flasked. Medical grade silicone was intrinsically stained to match the skin tone, following which it was packed, processed and finished. This clinical report describes a method of attaining retention by selective scoring of the master cast of partially amputated finger to enhance the vacuum effect at par with the proportional distribution of the positive forces on the tissues exerted by the prosthesis. PMID:23975917

  5. Fractal patterns formed by growth of radial viscous fingers*

    NASA Astrophysics Data System (ADS)

    Praud, Olivier

    2004-03-01

    We examine fractal patterns formed by the injection of air into oil in a thin (0.13 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell) [1]. The resultant radially grown patterns are similar to those formed in Diffusion Limited Aggregation (DLA), but the relation between the continuum limit of DLA and continuum (Laplacian) growth remains an open question. Our viscous fingering patterns in the limit of very high pressure difference reach an asymptotic state in which they exhibit a fractal dimension of 1.70± 0.02, in good agreement with a calculation of the fractal dimension of a DLA cluster, 1.713± 0.003 [2]. The generalized dimensions are also computed and show that the observed pattern is self-similar with Dq = 1.70 for all q. Further, the probability density function of shielding angles suggests the existence of a critical angle close to 75 degrees. This result is in accord with numerical and analytical evidence of a critical angle in DLA [3]. Thus fractal viscous fingering patterns and Diffusion Limited Aggregation clusters have a similar geometrical structure. *Work conducted in collaboration with H.L. Swinney, M.G. Moore and Eran Sharon [1] E. Sharon, M. G. Moore, W. D. McCormick, and H. L. Swinney, Phys. Rev. Lett. 91, 205504 (2003). [2] B.Davidovitch et A. Levermann and I. Procaccia, Phys. Rev. E 62, 5919 (2000). [3] D. A. Kessler et al., Phys. Rev. E 57, 6913 (1998).

  6. Finger Cooling During Cold Air Exposure.

    NASA Astrophysics Data System (ADS)

    Tikuisis, Peter

    2004-05-01

    This paper presents a method for predicting the onset of finger freezing. It is an extension of a tissue-cooling model originally developed to predict the onset of cheek freezing. The extension to the finger is presented as a more conservative warning of wind chill. Indeed, guidance on the risk of finger freezing is important not only to safeguard the finger, but also because it pertains more closely to susceptible facial features, such as the nose, than if only the risk of cheek freezing was provided. The importance of blood flow to the finger and the modeling of vaso-constriction are demonstrated through cooling predictions that agree reasonably well with several reported observations. Differences in the prediction between the present physiologic-based model and the engineering model used to develop the wind chill index are also discussed. New wind chill charts are presented that tabulate the mean cooling rates and corresponding onset times to freezing of the finger for various combinations of air temperature and wind speed. Results indicate that the surface of the finger cools to its freezing point in approximately one-eighth of the time predicted for the cheek. For combinations that result in the same wind chill temperature (WCT), the rate of finger cooling is faster at the higher wind speed. This asymmetry was previously disclosed through the application of the model to cheek cooling, and it reiterates the ambiguity associated with the reporting of WCT. It is further emphasized that the reporting of onset times to freezing, or safe exposure limits, is a more logical and meaningful alternative to the WCT.

  7. New Finger Biometric Method Using Near Infrared Imaging

    PubMed Central

    Lee, Eui Chul; Jung, Hyunwoo; Kim, Daeyeoul

    2011-01-01

    In this paper, we propose a new finger biometric method. Infrared finger images are first captured, and then feature extraction is performed using a modified Gaussian high-pass filter through binarization, local binary pattern (LBP), and local derivative pattern (LDP) methods. Infrared finger images include the multimodal features of finger veins and finger geometries. Instead of extracting each feature using different methods, the modified Gaussian high-pass filter is fully convolved. Therefore, the extracted binary patterns of finger images include the multimodal features of veins and finger geometries. Experimental results show that the proposed method has an error rate of 0.13%. PMID:22163741

  8. Electrocorticographic amplitude predicts finger positions during slow grasping motions of the hand

    NASA Astrophysics Data System (ADS)

    Acharya, Soumyadipta; Fifer, Matthew S.; Benz, Heather L.; Crone, Nathan E.; Thakor, Nitish V.

    2010-08-01

    Four human subjects undergoing subdural electrocorticography for epilepsy surgery engaged in a range of finger and hand movements. We observed that the amplitudes of the low-pass filtered electrocorticogram (ECoG), also known as the local motor potential (LMP), over specific peri-Rolandic electrodes were correlated (p < 0.001) with the position of individual fingers as the subjects engaged in slow and deliberate grasping motions. A generalized linear model (GLM) of the LMP amplitudes from those electrodes yielded predictions for positions of the fingers that had a strong congruence with the actual finger positions (correlation coefficient, r; median = 0.51, maximum = 0.91), during displacements of up to 10 cm at the fingertips. For all the subjects, decoding filters trained on data from any given session were remarkably robust in their prediction performance across multiple sessions and days, and were invariant with respect to changes in wrist angle, elbow flexion and hand placement across these sessions (median r = 0.52, maximum r = 0.86). Furthermore, a reasonable prediction accuracy for grasp aperture was achievable with as few as three electrodes in all subjects (median r = 0.49; maximum r = 0.90). These results provide further evidence for the feasibility of robust and practical ECoG-based control of finger movements in upper extremity prosthetics.

  9. Finger multibiometric cryptosystems: fusion strategy and template security

    NASA Astrophysics Data System (ADS)

    Peng, Jialiang; Li, Qiong; Abd El-Latif, Ahmed A.; Niu, Xiamu

    2014-03-01

    We address two critical issues in the design of a finger multibiometric system, i.e., fusion strategy and template security. First, three fusion strategies (feature-level, score-level, and decision-level fusions) with the corresponding template protection technique are proposed as the finger multibiometric cryptosystems to protect multiple finger biometric templates of fingerprint, finger vein, finger knuckle print, and finger shape modalities. Second, we theoretically analyze different fusion strategies for finger multibiometric cryptosystems with respect to their impact on security and recognition accuracy. Finally, the performance of finger multibiometric cryptosystems at different fusion levels is investigated on a merged finger multimodal biometric database. The comparative results suggest that the proposed finger multibiometric cryptosystem at feature-level fusion outperforms other approaches in terms of verification performance and template security.

  10. Scattering Removal for Finger-Vein Image Restoration

    PubMed Central

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

    Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic factors causing finger-vein image degradation, and then propose a simple but effective image restoration method based on scattering removal. To give a proper description of finger-vein image degradation, a biological optical model (BOM) specific to finger-vein imaging is proposed according to the principle of light propagation in biological tissues. Based on BOM, the light scattering component is sensibly estimated and properly removed for finger-vein image restoration. Finally, experimental results demonstrate that the proposed method is powerful in enhancing the finger-vein image contrast and in improving the finger-vein image matching accuracy. PMID:22737028

  11. Scattering removal for finger-vein image restoration.

    PubMed

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

    Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic factors causing finger-vein image degradation, and then propose a simple but effective image restoration method based on scattering removal. To give a proper description of finger-vein image degradation, a biological optical model (BOM) specific to finger-vein imaging is proposed according to the principle of light propagation in biological tissues. Based on BOM, the light scattering component is sensibly estimated and properly removed for finger-vein image restoration. Finally, experimental results demonstrate that the proposed method is powerful in enhancing the finger-vein image contrast and in improving the finger-vein image matching accuracy. PMID:22737028

  12. Crooked fingers and sparse hair: an interesting case of trichorhinophalangeal syndrome type 1.

    PubMed

    Narayanan, Ramakrishna; Chennareddy, Srinivasa

    2015-01-01

    Trichorhinophalangeal syndrome type 1 is a rare skeletal dysplasia of autosomal-dominant inheritance due to defects in the TRPS-1 gene. The syndrome is characterised by sparse slow-growing hair, a bulbous pear-shaped nose, cone-shaped epiphyses and deformities of the interphalangeal joints resembling those in rheumatoid arthritis. We present a case of trichorhinophalangeal syndrome in a 23-year-old man who presented with symmetrical painless progressive deformity of the fingers in both hands. PMID:25628322

  13. Man-equivalent telepresence through four fingered human-like hand system

    NASA Technical Reports Server (NTRS)

    Jau, Bruno M.

    1992-01-01

    The author describes a newly developed mechanical hand system. The robot hand is in human-like configuration with a thumb and three fingers, a palm, a wrist, and the forearm in which the hand and wrist actuators are located. Each finger and the wrist has its own active electromechanical compliance system, allowing the joint drive trains to be stiffened or loosened. This mechanism imitates the human muscle dual function of positioner and stiffness controller. This is essential for soft grappling operations. The hand-wrist assembly has 16 finger joints, three wrist joints, and five compliance mechanisms for a total of 24 degrees of freedom. The strength of the hand is roughly half that of the human hand and its size is comparable to a male hand. The hand is controlled through an exoskeleton glove controller that the operator wears. The glove provides the man-machine interface in telemanipulation control mode: it senses the operator's inputs to guide the mechanical hand in hybrid position and force control. The hand system is intended for dexterous manipulations in structured environments. Typical applications will include work in hostile environment such as space operations and nuclear power plants.

  14. Changes in joint laxity occurring during pregnancy.

    PubMed Central

    Calguneri, M; Bird, H A; Wright, V

    1982-01-01

    We have studied changes in peripheral joint laxity occurring during pregnancy in 68 females using both the finger hyperextensometer to quantify laxity at the metacarpophalangeal joint of the index finger and Beighton et al.'s modification of the Carter and Wilkinson scoring system. Although the latter system recorded no change, the more sensitive hyperextensometer demonstrated a significant increase in joint laxity during the last trimester of pregnancy (0.02 greater than p greater than 0.01) over the readings from the same individuals after parturition. When primigravidae and multigravidae were compared, a highly significant increase in laxity was found in women having their second baby over those having their first (0.01 greater than p greater than 0.001), though no further increase in laxity occurred in subsequent pregnancies. PMID:7073339

  15. Anthropomorphic finger antagonistically actuated by SMA plates.

    PubMed

    Engeberg, Erik D; Dilibal, Savas; Vatani, Morteza; Choi, Jae-Won; Lavery, John

    2015-10-01

    Most robotic applications that contain shape memory alloy (SMA) actuators use the SMA in a linear or spring shape. In contrast, a novel robotic finger was designed in this paper using SMA plates that were thermomechanically trained to take the shape of a flexed human finger when Joule heated. This flexor actuator was placed in parallel with an extensor actuator that was designed to straighten when Joule heated. Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend. Three different NiTi based SMA plates were evaluated for their ability to apply forces to a rigid and compliant object. The best of these three SMAs was able to apply a maximum fingertip force of 9.01N on average. A 3D CAD model of a human finger was used to create a solid model for the mold of the finger covering skin. Using a 3D printer, inner and outer molds were fabricated to house the actuators and a position sensor, which were assembled using a multi-stage casting process. Next, a nonlinear antagonistic controller was developed using an outer position control loop with two inner MOSFET current control loops. Sine and square wave tracking experiments demonstrated minimal errors within the operational bounds of the finger. The ability of the finger to recover from unexpected disturbances was also shown along with the frequency response up to 7 rad s(-1). The closed loop bandwidth of the system was 6.4 rad s(-1) when operated intermittently and 1.8 rad s(-1) when operated continuously. PMID:26292164

  16. The "open book" flap: a heterodigital cross-finger skin flap and adipofascial flap for coverage of a circumferential soft tissue defect of a digit.

    PubMed

    Tadiparthi, S; Akali, A; Felberg, L

    2009-02-01

    A case of circumferential digital skin loss with exposed tendons from the proximal phalanx to the distal interphalangeal joint is presented. This was treated with a two-layer heterodigital cross-finger ("open book") flap from the adjacent digit, utilising a skin-only cross-finger flap to cover the palmar defect and an adipofascial flap to cover the dorsal defect. PMID:19129359

  17. Ultrafast High-Resolution Mass Spectrometric Finger Pore Imaging in Latent Finger Prints

    NASA Astrophysics Data System (ADS)

    Elsner, Christian; Abel, Bernd

    2014-11-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record `three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals.

  18. Ultrafast High-Resolution Mass Spectrometric Finger Pore Imaging in Latent Finger Prints

    PubMed Central

    Elsner, Christian; Abel, Bernd

    2014-01-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record ‘three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals. PMID:25366032

  19. Ultrafast high-resolution mass spectrometric finger pore imaging in latent finger prints.

    PubMed

    Elsner, Christian; Abel, Bernd

    2014-01-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record 'three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals. PMID:25366032

  20. Reconstruction of Extensive Volar Finger Defects with Double Cross-Finger Flaps

    PubMed Central

    Buehrer, Gregor; Arkudas, Andreas; Ludolph, Ingo; Horch, Raymund E.

    2016-01-01

    Summary: Cross-finger flaps still represent a viable option to reconstruct small- to medium-sized full-thickness finger defects but they are not commonly used if larger areas have to be covered. We present 2 cases showing a simple and pragmatic approach with homodigital double cross-finger flaps to reconstruct extensive volar finger soft-tissue defects. We observed very low donor-site morbidity and excellent functional and aesthetic outcomes. Furthermore, there is no need for microsurgical techniques or equipment when using this method. Although this case report only addresses volar defects, one might also think of applying this concept to dorsal defects using reversed double cross-finger flaps. PMID:27200255

  1. FingerSight: Fingertip Haptic Sensing of the Visual Environment

    PubMed Central

    Horvath, Samantha; Galeotti, John; Wu, Bing; Klatzky, Roberta; Siegel, Mel

    2014-01-01

    We present a novel device mounted on the fingertip for acquiring and transmitting visual information through haptic channels. In contrast to previous systems in which the user interrogates an intermediate representation of visual information, such as a tactile display representing a camera generated image, our device uses a fingertip-mounted camera and haptic stimulator to allow the user to feel visual features directly from the environment. Visual features ranging from simple intensity or oriented edges to more complex information identified automatically about objects in the environment may be translated in this manner into haptic stimulation of the finger. Experiments using an initial prototype to trace a continuous straight edge have quantified the user's ability to discriminate the angle of the edge, a potentially useful feature for higher levels analysis of the visual scene. PMID:27170882

  2. The immediate effects of therapeutic keyboard music playing for finger training in adults undergoing hand rehabilitation

    PubMed Central

    Zhang, Xiaoying; Liu, Songhuai; Yang, Degang; Du, Liangjie; Wang, Ziyuan

    2016-01-01

    [Purpose] The purpose of this study was to examine the immediate effects of therapeutic keyboard music playing on the finger function of subjects’ hands through measurements of the joint position error test, surface electromyography, probe reaction time, and writing time. [Subjects and Methods] Ten subjects were divided randomly into experimental and control groups. The experimental group used therapeutic keyboard music playing and the control group used grip training. All subjects were assessed and evaluated by the joint position error test, surface electromyography, probe reaction time, and writing time. [Results] After accomplishing therapeutic keyboard music playing and grip training, surface electromyography of the two groups showed no significant change, but joint position error test, probe reaction time, and writing time obviously improved. [Conclusion] These results suggest that therapeutic keyboard music playing is an effective and novel treatment for improving joint position error test scores, probe reaction time, and writing time, and it should be promoted widely in clinics.

  3. Perceiving fingers in single-digit arithmetic problems.

    PubMed

    Berteletti, Ilaria; Booth, James R

    2015-01-01

    In this study, we investigate in children the neural underpinnings of finger representation and finger movement involved in single-digit arithmetic problems. Evidence suggests that finger representation and finger-based strategies play an important role in learning and understanding arithmetic. Because different operations rely on different networks, we compared activation for subtraction and multiplication problems in independently localized finger somatosensory and motor areas and tested whether activation was related to skill. Brain activations from children between 8 and 13 years of age revealed that only subtraction problems significantly activated finger motor areas, suggesting reliance on finger-based strategies. In addition, larger subtraction problems yielded greater somatosensory activation than smaller problems, suggesting a greater reliance on finger representation for larger numerical values. Interestingly, better performance in subtraction problems was associated with lower activation in the finger somatosensory area. Our results support the importance of fine-grained finger representation in arithmetical skill and are the first neurological evidence for a functional role of the somatosensory finger area in proficient arithmetical problem solving, in particular for those problems requiring quantity manipulation. From an educational perspective, these results encourage investigating whether different finger-based strategies facilitate arithmetical understanding and encourage educational practices aiming at integrating finger representation and finger-based strategies as a tool for instilling stronger numerical sense. PMID:25852582

  4. Finger millet [Eleusine coracana (L.) Gaertn].

    PubMed

    Ceasar, Stanislaus Antony; Ignacimuthu, Savarimuthu

    2015-01-01

    Millets are the primary food source for millions of people in tropical regions of the world supplying mineral nutrition and protein. In this chapter, we describe an optimized protocol for the Agrobacterium-mediated transformation of finger millet variety GPU 45. Agrobacterium strain LBA4404 harboring plasmid pCAMBIA1301 which contains hygromycin phosphotransferase (hph) as selectable marker gene and β-glucuronidase (GUS) as reporter gene has been used. This protocol utilizes the shoot apex explants for the somatic embryogenesis and regeneration of finger millet after the transformation by Agrobacterium. Desiccation of explants during cocultivation helps for the better recovery of transgenic plants. This protocol is very useful for the efficient production of transgenic plants in finger millet through Agrobacterium-mediated transformation. PMID:25300836

  5. Axon reflexes in human cold exposed fingers.

    PubMed

    Daanen, H A; Ducharme, M B

    2000-02-01

    Exposure of fingers to severe cold induces cold induced vasodilatation (CIVD). The mechanism of CIVD is still debated. The original theory states that an axon reflex causes CIVD. To test this hypothesis, axon reflexes were evoked by electrical stimulation of the middle fingers of hands immersed in water at either 5 degrees C or 35 degrees C. Axon reflexes were pronounced in the middle finger of the hand in warm water, but absent from the hand in cold water, even though the stimulation was rated as "rather painful" to "painful". These results showed that axon reflexes do not occur in a cold-exposed hand and thus are unlikely to explain the CIVD phenomenon. PMID:10638384

  6. Thermoregulatory control of finger blood flow

    NASA Technical Reports Server (NTRS)

    Wenger, C. B.; Roberts, M. F.; Nadel, E. R.; Stolwijk, J. A. J.

    1975-01-01

    In the present experiment, exercise was used to vary internal temperature and ambient air heat control was used to vary skin temperature. Finger temperature was fixed at about 35.7 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at different skin sites. Finger blood flow was measured by electrocapacitance plethysmography. An equation in these quantities is given which accounts for the data garnered.

  7. Analysis of the effects of surface stiffness on the contact interaction between a finger and a cylindrical handle using a three-dimensional hybrid model

    PubMed Central

    Wu, John Z.; Dong, Ren G.; Warren, Christopher M.; Welcome, Daniel E.; McDowell, Thomas W.

    2015-01-01

    Contact interactions between the hand and handle, such as the contact surface softness and contact surface curvature, will affect both physical effort and musculoskeletal fatigue, thereby the comfort and safety of power tool operations. Previous models of hand gripping can be categorized into two groups: multi-body dynamic models and finite element (FE) models. The goal of the current study is to develop a hybrid FE hand gripping model, which combines the features of conventional FE models and multi-body dynamic models. The proposed model is applied to simulate hand-gripping on a cylindrical handle with covering materials of different softness levels. The model included three finger segments (distal, middle, and proximal phalanxes), three finger joints (the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joint), and major anatomical substructures. The model was driven by joint moments, which are the net effects of all passive and active muscular forces acting about the joints. The finger model was first calibrated by using experimental data of human subject tests, and then applied to investigate the effects of surface softness on contact interactions between a finger and a cylindrical handle. Our results show that the maximal compressive stress and strain in the soft tissues of the fingers can be effectively reduced by reducing the stiffness of the covering material. PMID:24736020

  8. High-resolution solution structure of the double Cys2His2 zinc finger from the human enhancer binding protein MBP-1.

    PubMed

    Omichinski, J G; Clore, G M; Robien, M; Sakaguchi, K; Appella, E; Gronenborn, A M

    1992-04-28

    The high-resolution three-dimensional structure of a synthetic 57-residue peptide comprising the double zinc finger of the human enhancer binding protein MBP-1 has been determined in solution by nuclear magnetic resonance spectroscopy on the basis of 1280 experimental restraints. A total of 30 simulated annealing structures were calculated. The backbone atomic root-mean-square distributions about the mean coordinate positions are 0.32 and 0.33 A for the N- and C-terminal fingers, respectively, and the corresponding values for all atoms, excluding disordered surface side chains, are 0.36 and 0.40 A. Each finger comprises an irregular antiparallel sheet and a helix, with the zinc tetrahedrally coordinated to two cysteines and two histidines. The overall structure is nonglobular in nature, and the angle between the long axes of the helices is 47 +/- 5 degrees. The long axis of the antiparallel sheet in the N-terminal finger is approximately parallel to that of the helix in the C-terminal finger. Comparison of this structure with the X-ray structure of the Zif-268 triple finger complexed with DNA indicates that the relative orientation of the individual zinc fingers is clearly distinct in the two cases. This difference can be attributed to the presence of a long Lys side chain in the C-terminal finger of MBP-1 at position 40, instead of a short Ala or Ser side chain at the equivalent position in Zif-268. This finding suggests that different contacts may be involved in the binding of the zinc fingers of MBP-1 and Zif-268 to DNA, consistent with the findings from methylation interference experiments that the two fingers of MBP-1 contact 10 base pairs, while the three fingers of Zif-268 contact only 9 base pairs. PMID:1567844

  9. Interaction of finger enslaving and error compensation in multiple finger force production

    PubMed Central

    Martin, Joel R.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2009-01-01

    Previous studies have documented two patterns of finger interaction during multi-finger pressing tasks, enslaving and error compensation, which do not agree with each other. Enslaving is characterized by positive correlation between instructed (master) and non-instructed (slave) finger(s) while error compensation can be described as a pattern of negative correlation between master and slave fingers. We hypothesize that pattern of finger interaction, enslaving or compensation, depends on the initial force level and the magnitude of the targeted force change. Subjects were instructed to press with four fingers (I - index, M - middle, R - ring, and L - little) from a specified initial force to a target forces following a ramp target line. Force-force relations between master and each of three slave fingers were analyzed during the ramp phase of trials by calculating correlation coefficients within each master-slave pair and then 2-factor ANOVA was performed to determine effect of initial force and force increase on the correlation coefficients. It was found that, as initial force increased, the value of the correlation coefficient decreased and in some cases became negative, i.e. the enslaving transformed into error compensation. Force increase magnitude had a smaller effect on the correlation coefficients. The observations support the hypothesis that the pattern of inter-finger interaction—enslaving or compensation—depends on the initial force level and, to a smaller degree, on the targeted magnitude of the force increase. They suggest that the controller views tasks with higher steady-state forces and smaller force changes as implying a requirement to avoid large changes in the total force. PMID:18985331

  10. Wide Angle Movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief movie illustrates the passage of the Moon through the Saturn-bound Cassini spacecraft's wide-angle camera field of view as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. From beginning to end of the sequence, 25 wide-angle images (with a spatial image scale of about 14 miles per pixel (about 23 kilometers)were taken over the course of 7 and 1/2 minutes through a series of narrow and broadband spectral filters and polarizers, ranging from the violet to the near-infrared regions of the spectrum, to calibrate the spectral response of the wide-angle camera. The exposure times range from 5 milliseconds to 1.5 seconds. Two of the exposures were smeared and have been discarded and replaced with nearby images to make a smooth movie sequence. All images were scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is approximately the same in every image. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS)at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  11. Hypermobile joints

    MedlinePlus

    ... too far. In children with hypermobility syndrome, those ligaments are loose or weak. This may lead to: Arthritis, which may develop over time Dislocated joints, which is a separation of two bones where they meet at a joint Sprains and strains Children with hypermobile joints also often have flat ...

  12. Joint Disorders

    MedlinePlus

    A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, ...

  13. Fingerspell: Let Your Fingers Do the Talking

    ERIC Educational Resources Information Center

    Scarlatos, Tony; Nesterenko, Dmitri

    2004-01-01

    In this article we discuss an application that translates hand gestures of the American Sign Language (ASL) alphabet and converts them to text. The FingerSpell application addresses the communication barrier of the deaf and the hearing-impaired by eliminating the need for a third party with knowledge of the American Sign Language, allowing a user…

  14. Fingers Make a Comeback in Math

    ERIC Educational Resources Information Center

    Brooks, Andree

    1978-01-01

    Describes a new idea in finger-counting developed by 31 year old Hang Young Pai, a Korean teacher living in New York. It is called Chisanbop and it comes from a more advanced hand-calculation system used in the Orient in conjunction with the abacus. It is applicable for both elementary students and for more advanced mathematical applications, such…

  15. Finger arterial pressure measurement with Finapres.

    PubMed

    Wesseling, K H

    1996-01-01

    Finger arterial pressure measurement with Finapres has been available since a decade. Its availability has promoted at least 300 methodological and research papers over these years, outlining the usefulness and the limitations of the method and the device. Finapres is based on the volume clamp method of Peñáz and the Physiocal criteria of Wesseling. Tracking of intraarterial pressure is usually satisfactory even under conditions of strongly changing hemodynamics and high and very low blood pressures. Finapres accuracy is similar to that of other non-invasive methods. Systolic pressure levels scatter more than mean and diastolic levels. One source of error is physiologic and determined by the peripheral measurement site of the finger, causing pulse waveform distortion and a pressure gradient. The Finapres waveform can be filtered, however, to obtain a brachial pressure wave. This decreases systolic scatter under vaso-constrictive drug infusion and dynamic exercise to exhaustion, conditions where precision of systolic tracking has been criticized in the literature. Recently, level correction techniques were found which shift finger pressure up or down based on a regression equation with finger systolic and diastolic pressures. This procedure requires no additional measurements yet improves systolic, diastolic and mean level accuracy and precision remarkably. Finally, we show how to judge the quality of a Finapres recording from the behavior of Physiocal. PMID:8896298

  16. Viscous fingering with partial miscible fluids

    NASA Astrophysics Data System (ADS)

    Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

    2015-11-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Studies of viscous fingering have focused on fluids that are either fully miscible or perfectly immiscible. In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other. Following our recent work for miscible (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a Hele-Shaw cell, when the two fluids have limited (but nonzero) solubility in one another. Partial miscibility is characterized through the design of thermodynamic free energy of the two-fluid system. We elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution.

  17. Fingering phenomena during grain-grain displacement

    NASA Astrophysics Data System (ADS)

    Mello, Nathália M. P.; Paiva, Humberto A.; Combe, G.; Atman, A. P. F.

    2016-05-01

    Spontaneous formation of fingered patterns during the displacement of dense granular assemblies was experimentally reported few years ago, in a radial Hele-Shaw cell. Here, by means of discrete element simulations, we have recovered the experimental findings and extended the original study to explore the control parameters space. In particular, using assemblies of grains with different geometries (monodisperse, bidisperse, or polydisperse), we measured the macroscopic stress tensor in the samples in order to confirm some conjectures proposed in analogy with Saffman-Taylor viscous fingering phenomena for immiscible fluids. Considering an axial setup which allows to control the discharge of grains and to follow the trajectory and the pressure gradient along the displacing interface, we have applied the Darcy law for laminar flow in fluids in order to measure an "effective viscosity" for each assembly combination, in an attempt to mimic variation of the viscosity ratio between the injected/displaced fluids in the Saffman-Taylor experiment. The results corroborate the analogy with the viscous fluids displacement, with the bidisperse assembly corresponding to the less viscous geometry. But, differently to fluid case, granular fingers only develop for a specific combination of displaced/injected geometries, and we have demonstrated that it is always related with the formation of a force chain network along the finger direction.

  18. Compact Tactile Sensors for Robot Fingers

    NASA Technical Reports Server (NTRS)

    Martin, Toby B.; Lussy, David; Gaudiano, Frank; Hulse, Aaron; Diftler, Myron A.; Rodriguez, Dagoberto; Bielski, Paul; Butzer, Melisa

    2004-01-01

    Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure- or force-distribution feedback provided by these sensors is essential for the further development and implementation of robot-control capabilities for humanlike grasping and manipulation.

  19. Sticky fingers: Adhesive properties of human fingertips.

    PubMed

    Spinner, Marlene; Wiechert, Anke B; Gorb, Stanislav N

    2016-02-29

    Fingertip friction is a rather well studied subject. Although the phenomenon of finger stickiness is known as well, the pull-off force and the adhesive strength of human finger tips have never been previously quantified. For the first time, we provided here characterization of adhesive properties of human fingers under natural conditions. Human fingers can generate a maximum adhesive force of 15mN on a smooth surface of epoxy resin. A weak correlation of the adhesive force and the normal force was found on all test surfaces. Up to 300mN load, an increase of the normal force leads to an increase of the adhesive force. On rough surfaces, the adhesive strength is significantly reduced. Our data collected from untreated hands give also an impression of an enormous scattering of digital adhesion depending on a large set of inter-subject variability and time-dependent individual factors (skin texture, moisture level, perspiration). The wide inter- and intra-individual range of digital adhesion should be considered in developing of technical and medical products. PMID:26892897

  20. Finger force perception during ipsilateral and contralateral force matching tasks

    PubMed Central

    Park, Woo-Hyung; Leonard, Charles T.; Li, Sheng

    2010-01-01

    The aims of the present study were to compare matching performance between ipsilateral and contralateral finger force matching tasks and to examine the effect of handedness on finger force perception. Eleven subjects were instructed to produce reference forces by an instructed finger (index – I or little – L finger) and to reproduce the same amount force by the same or a different finger within the hand (i.e., ipsilateral matching task), or by a finger of the other hand (i.e., contralateral matching task). The results of the ipsilateral and contralateral tasks in the present study commonly showed that 1) the reference and matching forces were matched closely when the two forces were produced by the same or homologous finger(s) such as I/I task; 2) the weaker little finger underestimated the magnitude of reference force of the index finger (I/L task), even with the higher level of effort (relative force), but the two forces were matched when considering total finger forces; 3) the stronger index finger closely matched the reference force of the little finger with the lower level of relative force (i.e., L/I task); 4) when considering the constant errors, I/L tasks showed an underestimation and L/I tasks showed an overestimation compared to I/I tasks. There was no handedness effect during ipsilateral tasks. During the contralateral task, the dominant hand overestimated the force of the non-dominant hand, while the non-dominant hand attempted to match the absolute force of the dominant hand. The overall results support the notion that the absolute, rather than relative, finger force is perceived and reproduced during ipsilateral and contralateral finger force matching tasks, indicating the uniqueness of finger force perception. PMID:18488212

  1. Setting tool with retractable torque fingers

    SciTech Connect

    Nevels, D.L.; Baugh, J.L.

    1986-07-08

    A method is described of setting a liner in a well bore using a setting tool of the type adapted to be made up in a pipe string for releasably engaging a setting sleeve in a well bore, comprising the steps of: connecting a mandrel in the pipe string which has a setting nut with external connecting threads for engaging mating connecting threads located on the interior of a setting sleeve disposed about the mandrel, the mandrel being slidably disposed within the setting nut when the setting nut is engaging the setting sleeve, the mandrel being slidable between an extended, running-in position and a weight set-down position; mounting a torque collar on the mandrel exterior, the torque collar having at least one torque finger mounted thereon which is axially slidable on an external surface of the torque collar in a plane which is parallel to the longitudinal axis of the tool, the setting sleeve having at least one end notch adapted to receive the axially slidable torque finger; initially latching the mandrel to the setting sleeve with each torque finger received within its respective end notch; setting weight down on the pipe string from the well surface to release the latch and allow relative movement between the connecting threads of the setting nut and setting sleeve; applying right hand torque to the pipe string to release the connecting threads of the setting nut from the setting sleeve; temporarily lifting the pipe string and setting tool to test the disengagement of the setting nut; again resting the setting tool on the setting sleeve; rotating the pipe string to realign the torque finger and the setting sleeve end notch and reengage the torque finger with the end notch; and continuing to rotate to the right to rotate the setting sleeve during subsequent well bore operations.

  2. Testing of FTS fingers and interface using a passive compliant robot manipulator. [flight telerobot servicer

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Antrazi, Sami S.

    1992-01-01

    This report deals with testing of a pair of robot fingers designed for the Flight Telerobotic Servicer (FTS) to grasp a cylinder type of Orbital Replaceable Unit (ORU) interface. The report first describes the objectives of the study and then the testbed consisting of a Stewart Platform-based manipulator equipped with a passive compliant platform which also serves as a force/torque sensor. Kinematic analysis is then performed to provide a closed-form solution for the force inverse kinematics and iterative solution for the force forward kinematics using the Newton's Raphson Method. Mathematical expressions are then derived to compute force/torques applied to the FTS fingers during the mating/demating with the interface. The report then presents the three parts of the experimental study on the feasibility and characteristics of the fingers. The first part obtains data of forces applied by the fingers to the interface under various misalignments, the second part determines the maximum allowable capture angles for mating, and the third part processes and interprets the obtained force/torque data.

  3. Improving the fatigue resistance of adhesive joints in laminated wood structures

    SciTech Connect

    Laufenberg, T.L.; River, B.H.; Murmanis, L.L.; Christiansen, A.W.

    1988-08-01

    The premature fatigue failure of a laminated wood/epoxy test beam containing a cross-section finger joint was the subject of a multidisciplinary investigation to assess and advance the technology of adhesive joints in composite wood structures. This investigation, which has wide-spread applicability to all adhesively bonded joints, included (1) analysis of the data collected during fatigue testing, (2) microscopic examination of failed and unfailed surfaces and materials, (3) chemical characterization of the adhesive resin and its cure in the presence of wood and asbestos fibers, (4) testing of the filled adhesive on various adherent systems for its mechanical properties and its performance in prototype finger joints, and (5) analysis of the finger joint's load-carrying capabilities, including the effects of specific design modifications. Four major problem areas were identified which appeared to contribute to the premature fatigue failure. Recommended solutions of these problems would reduce the void content in the veneer-veneer and finger joint bondlines, provide a well-configured finger tip for the joint, improve the adhesive's penetration and bonding to the wood substrate, and provide a cleanly-machined surface. 2 refs., 11 figs., 2 tabs.

  4. Analysis of minor fractures associated with joints and faulted joints

    NASA Astrophysics Data System (ADS)

    Cruikshank, Kenneth M.; Zhao, Guozhu; Johnson, Arvid M.

    In this paper, we use fracture mechanics to interpret conditions responsible for secondary cracks that adorn joints and faulted joints in the Entrada Sandstone in Arches National Park, U.S.A. Because the joints in most places accommodated shearing offsets of a few mm to perhaps 1 dm, and thus became faulted joints, some of the minor cracks are due to faulting. However, in a few places where the shearing was zero, one can examine minor cracks due solely to interaction of joint segments at the time they formed. We recognize several types of minor cracks associated with subsequent faulting of the joints. One is the kink, a crack that occurs at the termination of a straight joint and whose trend is abruptly different from that of the joint. Kinks are common and should be studied because they contain a great deal of information about conditions during fracturing. The sense of kinking indicates the sense of shear during faulting: a kink that turns clockwise with respect to the direction of the main joint is a result of right-lateral shear, and a kink that turns counterclockwise is a result of left-lateral shear. Furthermore, the kink angle is related to the ratio of the shear stress responsible for the kinking to the normal stress responsible for the opening of the joint. The amount of opening of a joint at the time it faulted or even at the time the joint itself formed can be estimated by measuring the kink angle and the amount of strike-slip at some point along the faulted joint. Other fractures that form near terminations of pre-existing joints in response to shearing along the joint are horsetail fractures. Similar short fractures can occur anywhere along the length of the joints. The primary value in recognizing these fractures is that they indicate the sense of faulting accommodated by the host fracture and the direction of maximum tension. Even where there has been insignificant regional shearing in the Garden Area, the joints can have ornate terminations. Perhaps

  5. Robot-assisted Guitar Hero for finger rehabilitation after stroke.

    PubMed

    Taheri, Hossein; Rowe, Justin B; Gardner, David; Chan, Vicky; Reinkensmeyer, David J; Wolbrecht, Eric T

    2012-01-01

    This paper describes the design and testing of a robotic device for finger therapy after stroke: FINGER (Finger Individuating Grasp Exercise Robot). FINGER makes use of stacked single degree-of-freedom mechanisms to assist subjects in moving individual fingers in a naturalistic grasping pattern through much of their full range of motion. The device has a high bandwidth of control (-3dB at approximately 8 Hz) and is backdriveable. These characteristics make it capable of assisting in grasping tasks that require precise timing. We therefore used FINGER to assist individuals with a stroke (n= 8) and without impairment (n= 4) in playing a game similar to Guitar Hero©. The subjects attempted to move their fingers to target positions at times specified by notes that were graphically streamed to popular music. We show here that by automatically adjusting the robot gains, it is possible to use FINGER to modulate the subject's success rate at the game, across a range of impairment levels. Modulating success rates did not alter the stroke subject's effort, although the unimpaired subjects exerted more force when they were made less successful. We also present a novel measure of finger individuation that can be assessed as individuals play Guitar Hero with FINGER. The results demonstrate the ability of FINGER to provide controlled levels of assistance during an engaging computer game, and to quantify finger individuation after stroke. PMID:23366783

  6. Pressure Balanced, Low Hysteresis Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

    Arora, Gul K.; Proctor, Margaret; Steinetz, Bruce M.; Delgado, Irebert R.

    2000-01-01

    The purpose of this presentation is to demonstrate: low cost photoetching fabrication technique; pressure balanced finger seal design; and finger seal operation. The tests and analyses includes: finger seal air leakage analysis; rotor-run out and endurance tests; and extensive analytical work and rig testing.

  7. Left hand finger force in violin playing: tempo, loudness, and finger differences.

    PubMed

    Kinoshita, Hiroshi; Obata, Satoshi

    2009-07-01

    A three-dimensional force transducer was installed in the neck of a violin under the A string at the D5 position in order to study the force with which the violinist clamps the string against the fingerboard under normal playing conditions. Violinists performed repetitive sequences of open A- and fingered D-tones using the ring finger at tempi of 1, 2, 4, 8, and 16 notes/s at mezzo-forte. At selected tempi, the effects of dynamic level and the use of different fingers were investigated as well. The force profiles were clearly dependent on tempo and dynamic level. At slow tempi, the force profiles were characterized by an initial pulse followed by a level force to the end of the finger contact period. At tempi higher than 2 Hz, only pulsed profiles were observed. The peak force exceeded 4.5 N at 1 and 2 Hz and decreased to 1.7 N at 16 Hz. All force and impulse values were lower at softer dynamic levels, and when using the ring or little finger compared to the index finger. PMID:19603895

  8. Moment-angle relations after specific exercise.

    PubMed

    Ullrich, B; Kleinöder, H; Brüggemann, G P

    2009-04-01

    This study examined the amount and time-course of shifts in the moment-knee angle relation of the quadriceps (QF) and hamstring (HAM) muscles in response to different length-restricted strength training regimens. Thirty-two athletes were divided into three different training groups (G1-3): G1 performed isometric training at knee joint angles corresponding to long muscle-tendon unit (MTU) length for QF and HAM; G2 conducted concentric-eccentric contraction cycles that were restricted to a knee joint range of motion corresponding to predominantly long MTU length for QF and HAM; G3 combined the protocols of G1 and G2. Moment-knee angle and EMG-knee angle relations of QF and HAM were measured on five different occasions: two times before, after five and eight weeks of training and four weeks post training. Moments and EMG-data of each subject were normalized to the largest value produced at any knee joint position [% Max.]. Obtained by curve fitting, the optimal knee joint angle for QF moment production was significantly (P<0.05) shifted to longer MTU length in G1 and G3 after 5 weeks of training and in G2 after 8 weeks of training. Contrary, no significant shifts were detected for HAM. Our data suggest that the predominant MTU length during loading is a major trigger for human force-length adaptations. PMID:19199195

  9. Anisotropic colloidal transport and periodic stick-slip motion in cholesteric finger textures.

    PubMed

    Chen, Kui; Metcalf, Linnea P; Rivas, David P; Reich, Daniel H; Leheny, Robert L

    2015-06-01

    We have investigated the mobility of discoidal colloidal particles sedimenting within cholesteric finger textures formed by mixtures of the nematic liquid crystal 4-cyano-4'-pentylbiphenyl (5CB) and the chiral dopant 4-(2-methylbutyl)-4'-cyanobiphenyl (CB15) with cholesteric pitch p between 24 and 114 μm. The nickel disks, with radius 17 μm and thickness 300 nm, displayed varied transport behavior that depended on the size of the pitch and the orientation of the gravitational force with respect to the cholesteric axis. In textures with small pitch (p < 40 μm), the disks moved perpendicular to the axis irrespective of the orientation of gravity as a result of an elastic retarding force that prevented motion along the axis. In textures with larger pitch, the disks similarly moved perpendicular to the axis when the angle between the force and axis was large. When the angle was small, the disks displayed stick-slip motion caused by periodic yielding of the finger texture. A model considering viscous drag on the particles and the elastic energy cost of deforming the finger texture describes the stick-slip motion accurately. The effective drag viscosities obtained from the disk motion are anomalously large compared with those of pure nematic 5CB indicating a large contribution to the dissipation from the motion of disclinations in the texture in the vicinity of the translating disks. PMID:25875803

  10. Quantifying forearm muscle activity during wrist and finger movements by means of multi-channel electromyography.

    PubMed

    Gazzoni, Marco; Celadon, Nicolò; Mastrapasqua, Davide; Paleari, Marco; Margaria, Valentina; Ariano, Paolo

    2014-01-01

    The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG) is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1) the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2) the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1) it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2) hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported. PMID:25289669

  11. Quantifying Forearm Muscle Activity during Wrist and Finger Movements by Means of Multi-Channel Electromyography

    PubMed Central

    Gazzoni, Marco; Celadon, Nicolò; Mastrapasqua, Davide; Paleari, Marco; Margaria, Valentina; Ariano, Paolo

    2014-01-01

    The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG) is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1) the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2) the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1) it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2) hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported. PMID:25289669

  12. Narrow Angle movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief three-frame movie of the Moon was made from three Cassini narrow-angle images as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. The purpose of this particular set of images was to calibrate the spectral response of the narrow-angle camera and to test its 'on-chip summing mode' data compression technique in flight. From left to right, they show the Moon in the green, blue and ultraviolet regions of the spectrum in 40, 60 and 80 millisecond exposures, respectively. All three images have been scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is the same in each image. The spatial scale in the blue and ultraviolet images is 1.4 miles per pixel (2.3 kilometers). The original scale in the green image (which was captured in the usual manner and then reduced in size by 2x2 pixel summing within the camera system) was 2.8 miles per pixel (4.6 kilometers). It has been enlarged for display to the same scale as the other two. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  13. Fingering dynamics driven by a precipitation reaction: Nonlinear simulations

    NASA Astrophysics Data System (ADS)

    Shukla, Priyanka; De Wit, A.

    2016-02-01

    A fingering instability can develop at the interface between two fluids when the more mobile fluid is injected into the less-mobile one. For example, viscous fingering appears when a less viscous (i.e., more mobile) fluid displaces a more viscous (and hence less mobile) one in a porous medium. Fingering can also be due to a local change in mobility arising when a precipitation reaction locally decreases the permeability. We numerically analyze the properties of the related precipitation fingering patterns occurring when an A +B →C chemical reaction takes place, where A and B are reactants in solution and C is a solid product. We show that, similarly to reactive viscous fingering patterns, the precipitation fingering structures differ depending on whether A invades B or vice versa. This asymmetry can be related to underlying asymmetric concentration profiles developing when diffusion coefficients or initial concentrations of the reactants differ. In contrast to reactive viscous fingering, however, precipitation fingering patterns appear at shorter time scales than viscous fingers because the solid product C has a diffusivity tending to zero which destabilizes the displacement. Moreover, contrary to reactive viscous fingering, the system is more unstable with regard to precipitation fingering when the high-concentrated solution is injected into the low-concentrated one or when the faster diffusing reactant displaces the slower diffusing one.

  14. The Shape of a Gravity Finger

    SciTech Connect

    Zhan, Lang; Yortsos, Yanis

    2000-09-11

    A new gravity finger model was proposed in this report in the absence of interfacial tension but in the presence of gravities. This model considered differences in density and viscosity of the two fluids. Thus, it was able to represent both stable and unstable displacements, and the finger development along either the upper or the bottom walls of a channel. This solution recovers the Saffman - Taylar solution if gravity is neglected. The results of the solution are very similar to the solutions proposed by Brener et al. for the gravity number up to 10. The solution provided in this work only has one free parameter while the solution of Brener et al. has three.

  15. Nylon-muscle-actuated robotic finger

    NASA Astrophysics Data System (ADS)

    Wu, Lianjun; Jung de Andrade, Monica; Rome, Richard S.; Haines, Carter; Lima, Marcio D.; Baughman, Ray H.; Tadesse, Yonas

    2015-04-01

    This paper describes the design and experimental analysis of novel artificial muscles, made of twisted and coiled nylon fibers, for powering a biomimetic robotic hand. The design is based on circulating hot and cold water to actuate the artificial muscles and obtain fast finger movements. The actuation system consists of a spring and a coiled muscle within a compliant silicone tube. The silicone tube provides a watertight, expansible compartment within which the coiled muscle contracts when heated and expands when cooled. The fabrication and characterization of the actuating system are discussed in detail. The performance of the coiled muscle fiber in embedded conditions and the related characteristics of the actuated robotic finger are described.

  16. Saffman-Taylor fingering: why it is not a proper upscaled model of viscous fingering in a (even two-dimensional) random porous medium

    NASA Astrophysics Data System (ADS)

    Meheust, Y.; Toussaint, R.; Lovoll, G.; Maloy, K. J.

    2015-12-01

    P.G. Saffman & G. Taylor (1958) studied the stability of the interface between two immiscible fluids of different densities and viscosities when one displaces the other inside a Hele-Shaw (HS) cell. They showed that with a horizontal cell and if the displaced fluid is the more viscous, the interface is unstable and leads to a viscous fingering which they nearly fully modeled [1]. The HS geometry was introduced as a geometry imposing the same flow behavior as the Darcy-scale flow in a two-dimensional (2D) porous medium, and therefore allowing an analogy between the two configurations. This is however not obvious, since capillary forces act at very different scales in the two. Later, researchers performing unstable displacement experiments in HS cells containing random 2D porous media also observed viscous fingering at large viscosity ratios, but with invasion patterns very different from those of Saffman and Taylor (ST) [2-3]. It was however considered that the two processes were both Laplacian growth processes, i.e., processes in which the invasion probability density is proportional to the pressure gradient. Ten years ago, we investigated viscously-unstable drainage in 2D porous media experimentally and measured the growth activity as well as occupation probability maps for the invasion process [4-5]. We concluded that in viscous fingering in 2D porous media, the activity was rather proportional to the square of the pressure gradient magnitude (a so-called DBM model of exponent 2), so that the universality class of the growth/invasion process was different from that of ST viscous fingering. We now strengthen our claim with new results based on the comparison of (i) pressure measurements with the pressure field around a finger such as described by the ST analytical model, and (ii) branching angles in the invasion patterns with those expected for DBMs of various exponents. [1] Saffman, P. G. and Taylor, G. Proc. Soc. London 1958(Ser A 245), 312-329. [2] Lenormand, R

  17. Population Coding of Forelimb Joint Kinematics by Peripheral Afferents in Monkeys

    PubMed Central

    Umeda, Tatsuya; Seki, Kazuhiko; Sato, Masa-aki; Nishimura, Yukio; Kawato, Mitsuo; Isa, Tadashi

    2012-01-01

    Various peripheral receptors provide information concerning position and movement to the central nervous system to achieve complex and dexterous movements of forelimbs in primates. The response properties of single afferent receptors to movements at a single joint have been examined in detail, but the population coding of peripheral afferents remains poorly defined. In this study, we obtained multichannel recordings from dorsal root ganglion (DRG) neurons in cervical segments of monkeys. We applied the sparse linear regression (SLiR) algorithm to the recordings, which selects useful input signals to reconstruct movement kinematics. Multichannel recordings of peripheral afferents were performed by inserting multi-electrode arrays into the DRGs of lower cervical segments in two anesthetized monkeys. A total of 112 and 92 units were responsive to the passive joint movements or the skin stimulation with a painting brush in Monkey 1 and Monkey 2, respectively. Using the SLiR algorithm, we reconstructed the temporal changes of joint angle, angular velocity, and acceleration at the elbow, wrist, and finger joints from temporal firing patterns of the DRG neurons. By automatically selecting a subset of recorded units, the SLiR achieved superior generalization performance compared with a regularized linear regression algorithm. The SLiR selected not only putative muscle units that were responsive to only the passive movements, but also a number of putative cutaneous units responsive to the skin stimulation. These results suggested that an ensemble of peripheral primary afferents that contains both putative muscle and cutaneous units encode forelimb joint kinematics of non-human primates. PMID:23112841

  18. Vibration white finger: a follow up study.

    PubMed Central

    Ekenvall, L; Carlsson, A

    1987-01-01

    To study the course of vibration white finger (VWF) 55 men were re-examined three and a half to six years after the first examination. The patients were interviewed and finger systolic pressure after general body and local finger cooling was measured. The test results at the two examinations were compared. At the follow up examination some patients experienced a subjective improvement of VWF symptoms but not until more than three years had passed after they had stopped working with vibrating tools. To study the effect of diminished cold exposure on subjective symptoms, vibration exposed outdoor workers who changed to unexposed indoor work were studied separately. In this subgroup also improvement was reported only when more than three years has passed after the change of work, indicating that diminished cold exposure is not the primary explanation for the improvement. The cold provocation test, however, showed no tendency towards a diminished reaction of the vessels to cooling. Patients who continue to work with vibrating tools report a subjective increase in symptoms. This subjective impairment was reflected in an increased reaction to cold as measured in the cold provocation test. PMID:3620371

  19. Visual Foraging With Fingers and Eye Gaze

    PubMed Central

    Thornton, Ian M.; Smith, Irene J.; Chetverikov, Andrey; Kristjánsson, Árni

    2016-01-01

    A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a) The fact that a sizeable number of observers (in particular during gaze foraging) had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b) While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints. PMID:27433323

  20. Pacifier Use, Finger Sucking, and Infant Sleep.

    PubMed

    Butler, Rachel; Moore, Melisa; Mindell, Jodi A

    2016-01-01

    Few studies to date have investigated the relationship between pacifier use or finger sucking and infant sleep. One hundred and four mothers of infants (ages 0-11 months) completed the Brief Infant Sleep Questionnaire (BISQ). Infants who engaged in finger sucking had fewer night wakings and longer stretches of nighttime sleep, although less daytime sleep. There were no significant differences in sleep patterns between pacifier users and infants who did not engage in nonnutritive sucking. Furthermore, no significant differences were found across groups for sleep ecology, including parental involvement at bedtime and following night wakings. Finally, infants were consistently able to retrieve their pacifiers independently by 7 months of age, although this did not appear to be associated with sleep outcomes. Results suggest that when parents are deciding whether to give their infant a pacifier, sleep may not be a critical factor. In contrast, parents of finger and thumb suckers should be reassured that this nonnutritive sucking is beneficial to sleep, at least in the first year of life. PMID:26548755

  1. Multi-finger Prehension: An overview

    PubMed Central

    Zatsiorsky, Vladimir M.; Latash, Mark L.

    2009-01-01

    This paper reviews the available experimental evidence on what people do when they grasp an object with several digits and then manipulate it. In addition to the Introduction, the paper includes three parts each addressing a specific aspect of multi-finger prehension. Part II discusses manipulation forces, i.e. the resultant force and moment of force exerted on the object, and the digits contribution to such force production. Part III deals with internal forces defined as forces that cancel each other and do not disturb object equilibrium. The role of the internal forces in maintaining the object stability is discussed with respect to such issues as slip prevention, tilt prevention and resistance to perturbations. Part IV is devoted to the motor control of prehension. It covers such topics as prehension synergies, chain effects, the principle of superposition, inter-finger connection matrices and reconstruction of neural commands, mechanical advantage of the fingers, and the simultaneous digit adjustment to several mutually reinforcing or conflicting demands. PMID:18782719

  2. Palm to Finger Ulnar Sensory Nerve Conduction

    PubMed Central

    Davidowich, Eduardo; Orsini, Marco; Pupe, Camila; Pessoa, Bruno; Bittar, Caroline; Pires, Karina Lebeis; Bruno, Carlos; Coutinho, Bruno Mattos; de Souza, Olivia Gameiro; Ribeiro, Pedro; Velasques, Bruna; Bittencourt, Juliana; Teixeira, Silmar; Bastos, Victor Hugo

    2015-01-01

    Ulnar neuropathy at the wrist (UNW) is rare, and always challenging to localize. To increase the sensitivity and specificity of the diagnosis of UNW many authors advocate the stimulation of the ulnar nerve (UN) in the segment of the wrist and palm. The focus of this paper is to present a modified and simplified technique of sensory nerve conduction (SNC) of the UN in the wrist and palm segments and demonstrate the validity of this technique in the study of five cases of type III UNW. The SNC of UN was performed antidromically with fifth finger ring recording electrodes. The UN was stimulated 14 cm proximal to the active electrode (the standard way) and 7 cm proximal to the active electrode. The normal data from amplitude and conduction velocity (CV) ratios between the palm to finger and wrist to finger segments were obtained. Normal amplitude ratio was 1.4 to 0.76. Normal CV ratio was 0.8 to 1.23.We found evidences of abnormal SNAP amplitude ratio or substantial slowing of UN sensory fibers across the wrist in 5 of the 5 patients with electrophysiological-definite type III UNW. PMID:26788268

  3. The creation of the artificial RING finger from the cross-brace zinc finger by {alpha}-helical region substitution

    SciTech Connect

    Miyamoto, Kazuhide; Togiya, Kayo

    2010-04-16

    The creation of the artificial RING finger as ubiquitin-ligating enzyme (E3) has been demonstrated. In this study, by the {alpha}-helical region substitution between the EL5 RING finger and the Williams-Beuren syndrome transcription factor (WSTF) PHD finger, the artificial E3 (WSTF PHD{sub R}ING finger) was newly created. The experiments of the chemical modification of residues Cys and the circular dichroism spectra revealed that the WSTF PHD{sub R}ING finger binds two zinc atoms and adopts the zinc-dependent ordered-structure. In the substrate-independent ubiquitination assay, the WSTF PHD{sub R}ING finger functions as E3 and was poly- or mono-ubiquitinated. The present strategy is very simple and convenient, and consequently it might be widely applicable to the creation of various artificial E3 RING fingers with the specific ubiquitin-conjugating enzyme (E2)-binding capability.

  4. Viscous fingering with partially miscible fluids

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cueto-Felgueroso, L.; Juanes, R.

    2015-12-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Experimental and numerical studies of viscous fingering have focused on fluids that are either fully miscible (e.g. water and glycerol) or perfectly immiscible (e.g. water and oil). In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other (e.g. CO2 and water). Following our recent work for miscible systems (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a porous medium, when the two fluids have limited (but nonzero) solubility in one another. In our model, partial miscibility is characterized through the design of the thermodynamic free energy of the two-fluid system. We express the model in dimensionless form and elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution. Figure caption: final snapshots in simulations of viscous fingering with a two-fluid system mimicking that of CO2 and water. The colormap corresponds to the concentration of CO2. A band of less viscous gas phase rich in CO2 (red) displaces through the more viscous liquid phase that is undersaturated with CO2 (blue). At the fluid interface, an exchange of CO2 occurs as a result of local chemical potentials that drives the system towards thermodynamic equilibrium. This results in a shrinkage of gas phase as well as a local increase in

  5. [Osteoarthritis of the thumb and fingers].

    PubMed

    Waris, Eero; Waris, Ville; Konttinen, Yrjö T

    2012-01-01

    Most commonly affected joints of the hand in osteoarthritis include the carpometacarpal joint of the thumb (CMC 1) and the distal (DIP) and proximal (PIP) interphalangeal joints. Ageing, female gender, genotype, heavy work causing pressure on the hands, and injuries predispose to osteoarthritis in the hand. The pain is likely to be due to secondary synovitis caused by molecules released from the joint cartilage. Initial treatment of osteoarthritis is always conservative: analgesic medication, splint and physiotherapy. Surgery is considered for severe symptoms. The most common procedures include arthrodeses and arthroplasties with autogenous grafts or implants. PMID:22448556

  6. Mallet finger: a simulation and analysis of hyperflexion versus hyperextension injuries.

    PubMed

    Kreuder, Andrea; Pennig, Dietmar; Boese, Christoph Kolja; Eysel, Peer; Oppermann, Johannes; Dargel, Jens

    2016-05-01

    The goal of this study was to simulate the mechanisms of hyperflexion and hyperextension injuries of the distal interphalangeal (DIP) joint of the hand and to analyze the resulting extensor tendon injury patterns. The hypotheses were raised that hyperflexion trauma leads to a plastic deformation of the extensor tendon aponeurosis, with or without a small bony avulsion fragment but without joint surface involvement, and that hyperextension injuries can create a shear fracture of the dorsal lip of the distal phalanx, without injury to the extensor tendon aponeurosis. Loading was applied with a swinging pendulum impacting the distal phalanx in 103 human specimens in either an extended or flexion position. After loading, injury patterns were analyzed radiologically and histologically. There was evidence that hyperflexion trauma leads to a plastic deformation or rupture of the extensor tendon. Bony tendon avulsion was evident in 12.2 % of cases. With hyperextension, the extensor tendon remained intact in all cases, but there were large fracture fragments involving the articular surface in 4.1 % of cases. The results of the study show that force on the flexed joint leads to overstretching of the extensor tendon, and to an associated dorsal bony avulsion with intact joint line. Force applied to the joint in extension can lead to a bony dorsal edge fracture with articular involvement and with it, a palmar DIP joint capsule rupture. The results illuminate a direct correlation between the mechanism of injury and the pattern of injury in the clinical picture of mallet finger. PMID:26498933

  7. Ceramic joints

    DOEpatents

    Miller, Bradley J.; Patten, Jr., Donald O.

    1991-01-01

    Butt joints between materials having different coefficients of thermal expansion are prepared having a reduced probability of failure of stress facture. This is accomplished by narrowing/tapering the material having the lower coefficient of thermal expansion in a direction away from the joint interface and not joining the narrow-tapered surface to the material having the higher coefficient of thermal expansion.

  8. Relative contributions of neural mechanisms versus muscle mechanics in promoting finger extension deficits following stroke.

    PubMed

    Kamper, D G; Harvey, R L; Suresh, S; Rymer, W Z

    2003-09-01

    The origins of impaired finger and hand function were examined in 10 stroke survivors with chronic spastic hemiparesis, with the intent of assessing whether mechanical restraint or altered neurophysiological control mechanisms are responsible for the well-known impairment of finger extension. Simultaneous extension of all four metacarpophalangeal (MCP) joints of the impaired hand was either externally imposed using a rotary actuator or attempted voluntarily by the subject. Trials were conducted both before and after administration of a local anesthetic, blocking the median and ulnar nerves at the elbow. The anesthetic was administered to reduce the activity of the muscles flexing the MCP joints, in order to distinguish mechanical from neuronal resistance to imposed MCP rotation. We found that the nerve blockade resulted in a reduction in velocity-dependent torque (P = 0.01), thereby indicating significant joint impedance due to spasticity. Blockade also produced a posture-dependent reduction in static torque in declaratively relaxed subjects (P = 0.04), suggesting some tonic flexor activity for specific hand postures. No change in either extensor isometric (P = 0.33) or isokinetic (0.53) torque was apparent, but 3 of the 10 subjects did exhibit substantial (>10 degrees ) improvement in voluntary MCP extension following the blockade. This improvement seemed largely due to a decrease in inappropriate flexor activity during the movement, rather than an increase in extensor activity. We argue that persistent and inappropriate flexor activation plays a role in limiting voluntary finger extension, and that this activation is potentially a reflection of altered supraspinal control of key spinal pathways. In all cases, this inappropriate activation was compounded by weakness, apparent in both the extensor and flexor muscles. PMID:12929190

  9. Investigation on a three-cold-finger pulse tube cryocooler

    NASA Astrophysics Data System (ADS)

    Tang, Qingjun; Chen, Houlei; Cai, Jinghui

    2015-09-01

    This paper introduces a new type of pulse tube cryocooler, three-cold-finger pulse tube cryocooler (TCFPTC), which consists of one linear compressor and three cold fingers, i.e., CFA, CFB and CFC. Those three cold fingers are driven by the linear compressor simultaneously. This paper investigates two aspects. First, it studies the mass flow distribution among the three cold fingers by varying the input electrical power. The cooling powers of the three cold fingers at constant cooling temperatures and the cooling temperatures of the three cold fingers at constant cooling powers with various input electrical powers are investigated. Secondly, the interaction among the three cold fingers is investigated by varying the heating power of any one cold finger. Generally, if the heating power applied on one cold finger increases, with its cold head temperature rising up, the cold head temperatures of the others will decrease. But, when the cooling power of CFC has been 4 W, the cold head temperature of whichever cold finger increases, the cold head temperature of CFA or CFB will seldom change if its heating power keeps constant.

  10. Photoacoustic tomography of small-animal and human peripheral joints

    NASA Astrophysics Data System (ADS)

    Wang, Xueding; Chamberland, David L.; Fowlkes, J. Brian; Carson, Paul L.; Jamadar, David A.

    2008-02-01

    As an emerging imaging technology that combines the merits of both light and ultrasound, photoacoustic tomography (PAT) holds promise for screening and diagnosis of inflammatory joint diseases such as rheumatoid arthritis. In this study, the feasibility of PAT in imaging small-animal joints and human peripheral joints in a noninvasive manner was explored. Ex vivo rat tail and fresh cadaveric human finger joints were imaged. Based on the intrinsic optical contrast, intra- and extra-articular tissue structures in the joints were visualized successfully. Using light in the near-infrared region, the imaging depth of PAT is sufficient for cross-sectional imaging of a human peripheral joint as a whole organ. PAT, as a novel imaging modality with unique advantages, may contribute significantly to the early diagnosis of inflammatory joint disorders and accurate monitoring of disease progression and response to therapy.

  11. Does finger training increase young children's numerical performance?

    PubMed

    Gracia-Bafalluy, Maria; Noël, Marie-Pascale

    2008-04-01

    Butterworth (1999) suggested that fingers are important in representing numerosities. Furthermore, scores on a finger gnosis test are a better predictor of numerical performance up to 3 years later than intellectual measures (Marinthe et al., 2001; Noël, 2005). We hypothesised that training in finger differentiation would increase finger gnosis and might also improve numerical performance. Accordingly, 47 first-grade children were selected and divided into 3 groups: children with poor finger gnosis who followed the finger-differentiation training programme (G1), a control-intervention who were trained in story comprehension (G2), and a group with high finger gnosis scores who just continued with normal school lessons (G3). The finger training consisted of 2 weekly sessions of half an hour each, for 8 weeks. Before the training period, children in G3 performed better in finger gnosis and enumeration than children in the two other groups. After the training period this pattern remained for the children in G2 and G3, but the children in G1 were significantly better than those in G2 at finger gnosis, representation of numerosities with fingers, and quantification tasks; they also tended to be better at the processing of Arabic digits. These results indicate that improving finger gnosis in young children is possible and that it can provide a useful support to learning mathematics. Such an approach could be particularly appropriate for children with a developmental Gerstmann syndrome. Theoretically, these results are important because they suggest a functional link between finger gnosis and number skills. PMID:18387567

  12. Radial deviation of the finger caused by an occult intramuscular ganglion in a patient with rheumatoid arthritis.

    PubMed

    Kato, Tomoyuki; Iwamoto, Takuji; Matsumura, Noboru; Sato, Kazuki; Nakamura, Toshiyasu; Toyama, Yoshiaki

    2016-07-01

    Ulnar deviation is a common complication in patients with rheumatoid arthritis (RA). We report a case of an unusual radial deviation of the middle finger caused by an occult intramuscular ganglion of the second interosseous muscle (IOM) in a patient with RA. The resection of the ganglion did not resolve the problem, and the full range of motion of the metacarpophalangeal (MP) joint was achieved through dissection of the tendon of the second dorsal IOM. PMID:24834463

  13. Finger synergies during multi-finger cyclic production of moment of force

    PubMed Central

    Zhang, Wei; Zatsiorsky, Vladimir M.

    2010-01-01

    We investigated multi-finger synergies stabilizing the total moment of force and the total force when the subjects produced a quick cyclic change in the total moment of force. The seated subjects performed the task with the fingers of the dominant arm while paced by the metronome at 1.33 Hz. They were required to produce a rhythmic, sine-like change in the total pronation–supination moment of force computed with respect to the midpoint between the middle and ring fingers. The framework of the uncontrolled manifold hypothesis was used to compute indices of stabilization of the total moment and of the total force across 20 cycles. Variance of the total moment showed a cyclic pattern with peaks close to the peak rate of the moment change. Variance of the total force was maximal close to peak moment into supination. Higher magnitudes of the moment directed against the required moment direction (antagonist moment) were produced by individual fingers during supination efforts as compared to pronation efforts. Indices of multi-finger synergies showed across-trials stabilization of the total moment over the whole cycle but not of the total force. These indices were smaller during supination efforts. We conclude that the central nervous system facilitates multi-finger synergies stabilizing the total rotational action across a variety of tasks. Synergies stabilizing the total force are not seen in tasks that do not explicitly require accurate force control. Pronation efforts are performed more efficiently and with better stabilization of the action. PMID:16944107

  14. The Role of Vision in the Development of Finger-Number Interactions: Finger-Counting and Finger-Montring in Blind Children

    ERIC Educational Resources Information Center

    Crollen, Virginie; Mahe, Rachel; Collignon, Olivier; Seron, Xavier

    2011-01-01

    Previous research has suggested that the use of the fingers may play a functional role in the development of a mature counting system. However, the role of developmental vision in the elaboration of a finger numeral representation remains unexplored. In the current study, 14 congenitally blind children and 14 matched sighted controls undertook…

  15. Temporomandibular Joint, Closed

    MedlinePlus

    ... Oral Health > The Temporomandibular Joint, Closed The Temporomandibular Joint, Closed Main Content Title: The Temporomandibular Joint, Closed Description: The temporomandibular joint connects the lower ...

  16. Improved Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1995-01-01

    Proposed orthotic knee joint improved version of one described in "Automatically Locking/Unlocking Orthotic Knee Joint" (MFS-28633). Locks automatically upon initial application of radial force (wearer's weight) and unlocks automatically, but only when all loads (radial force and bending) relieved. Joints lock whenever wearer applies weight to knee at any joint angle between full extension and 45 degree bend. Both devices offer increased safety and convenience relative to conventional orthotic knee joints.

  17. Virtual Hand Feedback Reduces Reaction Time in an Interactive Finger Reaching Task.

    PubMed

    Brand, Johannes; Piccirelli, Marco; Hepp-Reymond, Marie-Claude; Morari, Manfred; Michels, Lars; Eng, Kynan

    2016-01-01

    Computer interaction via visually guided hand or finger movements is a ubiquitous part of daily computer usage in work or gaming. Surprisingly, however, little is known about the performance effects of using virtual limb representations versus simpler cursors. In this study 26 healthy right-handed adults performed cued index finger flexion-extension movements towards an on-screen target while wearing a data glove. They received each of four different types of real-time visual feedback: a simple circular cursor, a point light pattern indicating finger joint positions, a cartoon hand and a fully shaded virtual hand. We found that participants initiated the movements faster when receiving feedback in the form of a hand than when receiving circular cursor or point light feedback. This overall difference was robust for three out of four hand versus circle pairwise comparisons. The faster movement initiation for hand feedback was accompanied by a larger movement amplitude and a larger movement error. We suggest that the observed effect may be related to priming of hand information during action perception and execution affecting motor planning and execution. The results may have applications in the use of body representations in virtual reality applications. PMID:27144927

  18. Extraction of practice-dependent and practice-independent finger movement patterns.

    PubMed

    Furuya, Shinichi; Nakamura, Ayumi; Nagata, Noriko

    2014-08-01

    Extensive motor practice can reorganize movements of a redundant number of degrees of freedom (DOFs). Using principal component (PC) analysis, the present study characterized the movement reorganization of the hand that possesses a large number of DOFs during a course of practice. Five musically naïve individuals practiced to play a short sequence of melody with the left hand for four successive days, and their hand kinematics was measured using a motion capture system. The PC analysis of the hand joint kinematics identified two distinct patterns of movement, which accounted for more than 80% of the total variance of movements. The second PC but not the first PC changed through practice. A correlation analysis demonstrated that the PC sensitive to the practice was characterized by coupled movements across fingers in the same direction. A regression analysis identified a decrease in the contribution of this PC to the hand movement organization through practice, which indicates a reduction of the movement covariation across fingers and thus an enhancement of the individuated finger movements. The results implicate potential of PC analysis to extract practice-invariant and practice-dependent movement patterns distinctively in complex hand motor behaviors. PMID:24933539

  19. Virtual Hand Feedback Reduces Reaction Time in an Interactive Finger Reaching Task

    PubMed Central

    Brand, Johannes; Piccirelli, Marco; Hepp-Reymond, Marie-Claude; Morari, Manfred

    2016-01-01

    Computer interaction via visually guided hand or finger movements is a ubiquitous part of daily computer usage in work or gaming. Surprisingly, however, little is known about the performance effects of using virtual limb representations versus simpler cursors. In this study 26 healthy right-handed adults performed cued index finger flexion-extension movements towards an on-screen target while wearing a data glove. They received each of four different types of real-time visual feedback: a simple circular cursor, a point light pattern indicating finger joint positions, a cartoon hand and a fully shaded virtual hand. We found that participants initiated the movements faster when receiving feedback in the form of a hand than when receiving circular cursor or point light feedback. This overall difference was robust for three out of four hand versus circle pairwise comparisons. The faster movement initiation for hand feedback was accompanied by a larger movement amplitude and a larger movement error. We suggest that the observed effect may be related to priming of hand information during action perception and execution affecting motor planning and execution. The results may have applications in the use of body representations in virtual reality applications. PMID:27144927

  20. Visualization and Quantification of Fingering Flow Using Light Transmission Method

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Roth, K.

    2007-12-01

    With the aim of studying the physical process concerning the unstable fingering phenomena in two dimensions, experiments of vertical infiltration through layered sand were carried out in the laboratory using Hele-Shaw cells. We developed a light transmission method to measure the dynamics of water saturation within flow fingers in great detail with high spatial and temporal resolution. The method was calibrated using X-ray absorption. We improved the measured light transmission with correction for scattering effects through deconvolution with a point spread function which allows us to obtain quantitative high spatial resolution measurements. After fingers had fully developed, we added a dye tracer in order to distinguish mobile and immobile water fractions. Fully developed fingers consist of a tip, a core with mobile water, and a hull with immobile water. We analyzed the dynamics of water saturation within the finger tip, along the finger core behind the tip, and within the fringe of the fingers during radial growth. Our results confirm previous findings of saturation overshoot in the finger tips and revealed a saturation minimum behind the tip as a new feature. The finger development was characterized by a gradual increase in water content within the core of the finger behind this minimum and a gradual widening of the fingers to a quasi-stable state which evolves at time scales that are orders of magnitude longer than those of fingers' evolution. In this state, a sharp separation into a core with fast convective flow and a fringe with exceedingly slow flow was detected. All observed phenomena, with the exception of saturation overshoot, could be consistently explained based on the hysteretic behavior of the soil-water characteristic.

  1. Experimental study of fingered flow through initially dry sand

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Vogel, H.-J.; Roth, K.

    2006-08-01

    Water infiltration into coarse textured dry porous media becomes instable depending on flow conditions characterized through dimensionless quantities, i.e. the Bond number and the Capillary number. Instable infiltration fronts break into flow fingers which we investigate experimentally using Hele-Shaw cells. We further developed a light transmission method to measure the dynamics of water within flow fingers in great detail with high spatial and temporal resolution. The method was calibrated using x-ray absorption and the measured light transmission was corrected for scattering effects through deconvolution with a point spread function. Additionally we applied a dye tracer to visualize the velocity field within flow fingers. We analyzed the dynamics of water within the finger tips, along the finger core behind the tip, and within the fringe of the fingers during radial growth. Our results confirm previous findings of saturation overshoot in the finger tips and revealed a saturation minimum behind the tip as a new feature. The finger development was characterized by a gradual increase in water content within the core of the finger behind this minimum and a gradual widening of the fingers to a quasi-stable state which evolves on time scales that are orders of magnitudes longer than those of fingers' evolution. In this state, a sharp separation into a core with fast convective flow and a fringe with exceedingly slow flow was detected. All observed phenomena could by consistently explained based on the hysteretic behavior of the soil- water characteristic and on the positive pressure induced at the finger tip by the high flow velocity.

  2. Fingering instabilities in Newtonian and non-Newtonian fluids

    NASA Astrophysics Data System (ADS)

    Kennedy, Kristi E.

    Fingering has been studied in different fluid systems. Viscous fingering, which is driven by a difference in viscosity between fluids, has been studied by both experiments and numerical simulations. We used a single fluid with a temperature-dependent viscosity and studied the instability for a range of inlet pressures and viscosity ratios. The spreading and fingering of a fluid drop subjected to a centrifugal force, known as spin coating, has also been studied for a range of drop volumes and rotation speeds, both for a Newtonian and a non-Newtonian fluid. Experiments on viscous fingering with a single fluid, glycerine, show that an instability occurs at the boundary separating hot and cold fluid. The results indicate that the instability is similar to that which occurs between two miscible fluids. Fingering only occurs for high enough values of the inlet pressure and viscosity ratio. The wavelength of the fingering pattern is found to be proportional to the cell width for the two smallest cell widths used. The fingering patterns seen in the simulations are very similar to the experimental patterns, although there are some quantitative differences. In particular, the wavelength of the instability is seen to depend only weakly on the cell width. The spreading of silicone oil, a Newtonian fluid, during spin coating follows the time dependence predicted theoretically, although with a shift in the scaled time variable. Once the radius of the spreading silicone oil drop becomes large enough, fingers form around the perimeter of the drop for all experimental conditions studied. The number of fingers and the growth rate of the fingers are in agreement with theoretical predictions. Fingers are also observed to form for high enough drop volumes and rotation speeds during the spinning of a non-Newtonian fluid drop, Carbopol, which possesses a yield stress. In this case the fingering is a localized effect, occuring once the stress on the drop exceeds the yield stress, rather

  3. Joint Problems

    MedlinePlus

    ... ankles and toes. Other types of arthritis include gout or pseudogout. Sometimes, there is a mechanical problem ... for more information on osteoarthritis, rheumatoid arthritis and gout. How Common are Joint Problems? Osteoarthritis, which affects ...

  4. Joint pain

    MedlinePlus

    ... or conditions. It may be linked to arthritis , bursitis , and muscle pain . No matter what causes it, ... Autoimmune diseases such as rheumatoid arthritis and lupus Bursitis Chondromalacia patellae Crystals in the joint: gout (especially ...

  5. Compliant joint

    NASA Technical Reports Server (NTRS)

    Eklund, Wayne D. (Inventor); Kerley, James J. (Inventor)

    1990-01-01

    A compliant joint is provided for prosthetic and robotic devices which permits rotation in three different planes. The joint provides for the controlled use of cable under motion. Perpendicular outer mounting frames are joined by swaged cables that interlock at a center block. Ball bearings allow for the free rotation of the second mounting frame relative to the first mounting frame within a predetermined angular rotation that is controlled by two stop devices. The cables allow for compliance at the stops and the cables allow for compliance in six degrees of freedom enabling the duplication or simulation of the rotational movement and flexibility of a natural hip or knee joint, as well as the simulation of a joint designed for a specific robotic component for predetermined design parameters.

  6. Stick-slip instability for viscous fingering in a gel

    NASA Astrophysics Data System (ADS)

    Puff, N.; Debrégeas, G.; di Meglio, J.-M.; Higgins, D.; Bonn, D.; Wagner, C.

    2002-05-01

    The growth dynamics of an air finger injected in a visco-elastic gel (a PVA/borax aqueous solution) is studied in a linear Hele-Shaw cell. Besides the standard Saffman-Taylor instability, we observe—with increasing finger velocities—the existence of two new regimes: (a) a stick-slip regime for which the finger tip velocity oscillates between 2 different values, producing local pinching of the finger at regular intervals; (b) a "tadpole" regime where a fracture-type propagation is observed. A scaling argument is proposed to interpret the dependence of the stick-slip frequency with the measured rheological properties of the gel.

  7. Multiple trigger fingers in a musician: a case report.

    PubMed

    Yavari, Masoud; Hassanpour, Seyed Esmail; Mosavizadeh, Seyed Mehdi

    2010-05-01

    Trigger finger is a common disease which particularly occurs in middle-aged women. We present a rare case of a male musician with six trigger fingers (five in the left hand and one in the right hand). Mostly these fingers had been used for playing the guitar. The patient had previously been treated with local steroid injections in his fingers, however no response was seen. Therefore, we performed a surgical procedure. Four weeks after surgery, the patient could play the guitar without discomfort in his hands. PMID:20433233

  8. Vibration white finger and digital systolic pressure during cooling.

    PubMed Central

    Ekenvall, L; Lindblad, L E

    1986-01-01

    A cold provocation test (measurement of finger systolic pressure during combined body and local finger cooling) was performed on 111 male patients exposed to vibration and with a typical history of cold induced white finger. A new method of calculating the test result is described--namely, digital systolic blood pressure in the cooled test finger as a percentage of the systolic pressure in the arm (DP%). The conventional way of calculating the result, the systolic pressure in the cooled test finger as a percentage of the systolic pressure in the test finger when heated to 30 degrees C, corrected for changes in systemic pressure by the use of a reference finger (FSP%), requires the measurement of the systolic pressure in a reference finger. The two ways of calculating the test results give a similar sensitivity (74% for FSP%, 79% for DP% if all histories are regarded as true) but the new method does not require pressure measurements in a reference finger. This makes the test easier to perform and the result easier to understand. PMID:3964577

  9. Numerical Simulations and an Experimental Investigation of a Finger Seal

    NASA Technical Reports Server (NTRS)

    Braun, Minel; Pierson, Hazel; Li, H.; Dong, Dingeng

    2006-01-01

    Besides sealing, the other main goal of a successful finger seal design is to exhibit appropriate compliance to outside forces. The ability of the seal to ride or float along the rotor without rubbing or excessive heating is essential to the successful operation of the seal. The compliance of the finger must only occur in the radial plane; The seal needs to be as sturdy as possible in the axial direction. The compliant finger that moves radially outward with rotor growth and motion has to be able to ride the rotor back down as the rotor diameter recovers or the rotor moves "away". Thus there is an optimum stiffness for the finger.

  10. Impact of artificial "gummy" fingers on fingerprint systems

    NASA Astrophysics Data System (ADS)

    Matsumoto, Tsutomu; Matsumoto, Hiroyuki; Yamada, Koji; Hoshino, Satoshi

    2002-04-01

    Potential threats caused by something like real fingers, which are called fake or artificial fingers, should be crucial for authentication based on fingerprint systems. Security evaluation against attacks using such artificial fingers has been rarely disclosed. Only in patent literature, measures, such as live and well detection, against fake fingers have been proposed. However, the providers of fingerprint systems usually do not mention whether or not these measures are actually implemented in emerging fingerprint systems for PCs or smart cards or portable terminals, which are expected to enhance the grade of personal authentication necessary for digital transactions. As researchers who are pursuing secure systems, we would like to discuss attacks using artificial fingers and conduct experimental research to clarify the reality. This paper reports that gummy fingers, namely artificial fingers that are easily made of cheap and readily available gelatin, were accepted by extremely high rates by 11 particular fingerprint devices with optical or capacitive sensors. We have used the molds, which we made by pressing our live fingers against them or by processing fingerprint images from prints on glass surfaces, etc. We describe how to make the molds, and then show that the gummy fingers, which are made with these molds, can fool the fingerprint devices.

  11. Finger-Vein Verification Based on Multi-Features Fusion

    PubMed Central

    Qin, Huafeng; Qin, Lan; Xue, Lian; He, Xiping; Yu, Chengbo; Liang, Xinyuan

    2013-01-01

    This paper presents a new scheme to improve the performance of finger-vein identification systems. Firstly, a vein pattern extraction method to extract the finger-vein shape and orientation features is proposed. Secondly, to accommodate the potential local and global variations at the same time, a region-based matching scheme is investigated by employing the Scale Invariant Feature Transform (SIFT) matching method. Finally, the finger-vein shape, orientation and SIFT features are combined to further enhance the performance. The experimental results on databases of 426 and 170 fingers demonstrate the consistent superiority of the proposed approach. PMID:24196433

  12. Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Proposed orthotic knee joint locks and unlocks automatically, at any position within range of bend angles, without manual intervention by wearer. Includes tang and clevis, locks whenever wearer transfers weight to knee and unlocks when weight removed. Locking occurs at any angle between 45 degrees knee bend and full extension.

  13. A practical method for three-dimensional reconstruction of joints using a C-arm system and shift-and-add algorithm

    SciTech Connect

    Li Senhu; Jiang Huabei

    2005-06-15

    Currently, radiography with C-arm systems is playing a major role in the assessment of arthritis. However, the radiographic two-dimensional projection images of joints often interfere with physicians' efforts to better understand and measure the structure changes of joints due to the overlap of bone structures at different depths. An accurate, low-cost, and practical three-dimensional (3D) reconstruction approach of joints will be beneficial in diagnosing arthritis. Toward this end, a novel method is developed in this paper based on a C-arm system. The idea is to apply the shift-and-add algorithm (commonly used in digital tomosynthesis) on the segmented projection images at multiple angles, which results in accurate reconstruction of the 3D structures of joints. The method provides a new solution to precisely distinguish objects from blurring background. The proposed method has been tested and evaluated on simulated cylinders, a chicken bone phantom with known structure, and an in vivo human index finger. The results are demonstrated and discussed.

  14. Natural Experiments in Outcrop- vs. Landscape-scale Controls on Longitudinal Profile Form, Finger Lakes, NY

    NASA Astrophysics Data System (ADS)

    Safran, E. B.; Hauser, D.; Hoke, G. D.; Knuepfer, P. L.

    2012-12-01

    Longitudinal stream profiles are commonly used to extract information about the geologic histories of transient landscapes. Correct interpretation of these histories requires understanding the impacts on profile morphology of outcrop-scale controls relative to those imposed by landscape-scale processes driving incision. Previous researchers have suggested that joint-perpendicular channel reaches form waterfalls while joint-oblique channel reaches form cascades. The Finger Lakes region of central New York offers a natural laboratory in which to test this hypothesis. The region is underpinned primarily by relatively flat-lying, well-jointed Devonian shales of the Hamilton Group. Ice retreated from the region and pro-glacial lake levels fell episodically some 14 ka ago, triggering post-glacial incision through plucking and abrasion that has sculpted gorges and waterfalls. All post-glacial streams draining to a given lake have essentially a common lithology and base level history. Using GIS, we analyzed the orientation of 50 m long channel segments relative to mapped patterns of joint orientation. All moderately sized (<20 km2) streams exhibit convex profiles which mimic the overall form of the valley slopes. For streams draining to southern Cayuga Lake, joint perpendicular reaches had an average slope of 4.2 degrees, while joint oblique reaches had an average slope of 3.6 degrees (p = 3e-19). However, the spatial location of major knickpoints do not appear to be controlled by joint orientation patterns, whose alignment with channel orientation varies over wavelengths shorter than knickpoint spacing (order 10-100 m vs. order 100-1000 m). On the other hand, knickpoint location and spacing along streams draining to southern Seneca Lake do not appear to differ systematically from those of the Cayuga profiles. Since Seneca's lake level was more stable than Cayuga's during glacial retreat, this suggests that base level history alone is also not controlling profile

  15. A comprehensive assessment of cardiovascular autonomic control using photoplethysmograms recorded from the earlobe and fingers.

    PubMed

    Kiselev, A R; Mironov, S A; Karavaev, A S; Kulminskiy, D D; Skazkina, V V; Borovkova, E I; Shvartz, V A; Ponomarenko, V I; Prokhorov, M D

    2016-04-01

    We compare the spectral indices of photoplethysmogram variability (PPGV) estimated using photoplethysmograms recorded from the earlobe and the middle fingers of the right and left hand and analyze their correlation with similar indices of heart rate variability (HRV) in 30 healthy subjects (26 men) aged 27 (25, 29) years (median with inter-quartile ranges) at rest and under the head-up tilt test. The following spectral indices of PPGV and HRV were compared: mean heart rate (HR), total spectral power (TP), high-frequency (HF) and low-frequency (LF) ranges of TP in percents (HF% and LF%), LF/HF ratio, and spectral coherence. We assess also the index S of synchronization between the LF oscillations in HRV and PPGV. The constancy of blood pressure (BP) and moderate increase of HR under the tilt test indicate the presence of fast processes of cardiovascular adaptation with the increase of the sympathetic activity in studied healthy subjects. The impact of respiration on the PPGV spectrum (accessed by HF%) is less than on the HRV spectrum. It is shown that the proportion of sympathetic vascular activity (accessed by LF%) is constant in the PPGV of three analyzed PPGs during the tilt test. The PPGV for the ear PPG was less vulnerable to breathing influence accessed by HF% (independently from body position) than for PPGs from fingers. We reveal the increase of index S under the tilt test indicating the activation of interaction between the heart and distal vessels. The PPGV spectra for finger PPGs from different hands are highly coherent, but differ substantially from the PPGV spectrum for the ear PPG. We conclude that joint analysis of frequency components of PPGV (for the earlobe and finger PPGs of both hands) and HRV and assessment of their synchronization provide additional information about cardiovascular autonomic control. PMID:27027461

  16. Modeling and Control of Three-Dimensional Grasping by a Pair of Robot Fingers

    NASA Astrophysics Data System (ADS)

    Arimoto, Suguru; Yoshida, Morio

    This paper extends a stability theory of 2-D object grasp to cope with 3-dimensional(3-D) object grasp by a pair of multi-joint robot fingers with hemi-spheric ends. It shows that secure grasp of a 3-D object with parallel surfaces in a dynamic sense can be realized in a blind manner like human grasp an object by a pair of thumb and index finger while their eyes closed. Rolling contacts are modeled as Pfaffian constraints that can not be integrated into holonomic constraints but exert tangential constraint forces on the object surfaces. A noteworthy difference of modeling of 3-D object grasping from the 2-D case is that the instantaneous axis of rotation of the object dynamics of the overall fingers-object system are subject to non-holonomic constraints regarding a 3-D orthogonal matrix consisting of three mutually orthogonal unit-vectors fixed at the object. Lagrange's equation of motion of the overall system can be derived from the variational principle without violating the causality that governs the nonholonomic constraints. Then, a simple control signal constructed on the basis of fingers-thumb opposable forces together with an object-mass estimator is shown to accomplish stable grasp in a dynamic sense without using object information or external sensing. The closed-loop dynamics can be regarded as Lagrange's equation of motion with an artificial potential function that attains its minimum at some equilibrium state of force/torque balance. A mathematical proof of stability and asymptotic stability on a constraint manifold of the closed-loop dynamics under the nonholonomic constraints is presented.

  17. Teleoperation of Robonaut Using Finger Tracking

    NASA Technical Reports Server (NTRS)

    Champoux, Rachel G.; Luo, Victor

    2012-01-01

    With the advent of new finger tracking systems, the idea of a more expressive and intuitive user interface is being explored and implemented. One practical application for this new kind of interface is that of teleoperating a robot. For humanoid robots, a finger tracking interface is required due to the level of complexity in a human-like hand, where a joystick isn't accurate. Moreover, for some tasks, using one's own hands allows the user to communicate their intentions more effectively than other input. The purpose of this project was to develop a natural user interface for someone to teleoperate a robot that is elsewhere. Specifically, this was designed to control Robonaut on the international space station to do tasks too dangerous and/or too trivial for human astronauts. This interface was developed by integrating and modifying 3Gear's software, which includes a library of gestures and the ability to track hands. The end result is an interface in which the user can manipulate objects in real time in the user interface. then, the information is relayed to a simulator, the stand in for Robonaut, at a slight delay.

  18. Lipid Gymnastics: Tethers and Fingers in membrane

    NASA Astrophysics Data System (ADS)

    Tayebi, Lobat; Miller, Gregory; Parikh, Atul

    2009-03-01

    A significant body of evidence now links local mesoscopic structure (e.g., shape and composition) of the cell membrane with its function; the mechanisms by which cellular membranes adopt the specific shapes remain poorly understood. Among all the different structures adopted by cellular membranes, the tubular shape is one of the most surprising one. While their formation is typically attributed to the reorganization of membrane cytoskeleton, many exceptions exist. We report the instantaneous formation of tubular membrane mesophases following the hydration under specific thermal conditions. The shapes emerge in a bimodal way where we have two distinct diameter ranges for tubes, ˜20μm and ˜1μm, namely fat fingers and narrow tethers. We study the roughening of hydrated drops of 3 lipids in 3 different spontaneous curvatures at various temp. and ionic strength to figure out the dominant effect in selection of tethers and fingers. Dynamics of the tubes are of particular interest where we observe four distinct steps of birth, coiling, uncoiling and retraction with different lifetime on different thermal condition. These dynamics appear to reflect interplay between membrane elasticity, surface adhesion, and thermal or hydrodynamic gradient.

  19. Perception of Perspective Angles.

    PubMed

    Erkelens, Casper J

    2015-06-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles between bars lying on the floor of the laboratory. Perspective angles were also estimated from pictures taken from the same point of view. Converging and diverging angles were judged to test three models of visual space. Four subjects evaluated the perspective angles by matching them to nonperspective angles, that is, angles between the legs of a compass oriented in the frontal plane. All subjects judged both converging and diverging angles larger than the physical angle and smaller than the angles in the proximal stimuli. A model of shallow visual space describes the results. According to the model, lines parallel to visual lines, vanishing at infinity in physical space, converge to visual lines in visual space. The perceived shape of perspective angles is incompatible with the perceived length and width of the bars. The results have significance for models of visual perception and practical implications for driving and flying in poor visibility conditions. PMID:27433312

  20. Perception of Perspective Angles

    PubMed Central

    2015-01-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles between bars lying on the floor of the laboratory. Perspective angles were also estimated from pictures taken from the same point of view. Converging and diverging angles were judged to test three models of visual space. Four subjects evaluated the perspective angles by matching them to nonperspective angles, that is, angles between the legs of a compass oriented in the frontal plane. All subjects judged both converging and diverging angles larger than the physical angle and smaller than the angles in the proximal stimuli. A model of shallow visual space describes the results. According to the model, lines parallel to visual lines, vanishing at infinity in physical space, converge to visual lines in visual space. The perceived shape of perspective angles is incompatible with the perceived length and width of the bars. The results have significance for models of visual perception and practical implications for driving and flying in poor visibility conditions. PMID:27433312

  1. Circuitry for Angle Measurements

    NASA Technical Reports Server (NTRS)

    Currie, J. R.; Kissel, R. R.

    1983-01-01

    Angle resolver pulsed and read under microprocessor control. Pulse generator excites resolver windings with dual slope pulse. System sequentially reads sine and cosine windings. Microprocessor determines angle through which resolver shaft turned from reference angle. Suitable applications include rate tables, antenna direction controllers, and machine tools.

  2. Handedness and index finger movements performed on a small touchscreen.

    PubMed

    Aoki, Tomoko; Rivlis, Gil; Schieber, Marc H

    2016-02-01

    Many studies of right/left differences in motor performance related to handedness have employed tasks that use arm movements or combined arm and hand movements rather than movements of the fingers per se, the well-known exception being rhythmic finger tapping. We therefore explored four simple tasks performed on a small touchscreen with relatively isolated movements of the index finger. Each task revealed a different right/left performance asymmetry. In a step-tracking Target Task, left-handed subjects showed greater accuracy with the index finger of the dominant left hand than with the nondominant right hand. In a Center-Out Task, right-handed subjects produced trajectories with the nondominant left hand that had greater curvature than those produced with the dominant right hand. In a continuous Circle Tracking Task, slips of the nondominant left index finger showed higher jerk than slips of the dominant right index finger. And in a continuous Complex Tracking Task, the nondominant left index finger showed shorter time lags in tracking the relatively unpredictable target than the dominant right index finger. Our findings are broadly consistent with previous studies indicating left hemisphere specialization for dynamic control and predictable situations vs. right hemisphere specialization for impedance control and unpredictable situations, the specialized contributions of the two hemispheres being combined to different degrees in the right vs. left hands of right-handed vs. left-handed individuals. PMID:26683065

  3. Toward a Phonetic Representation of Hand Configuration: The Fingers

    ERIC Educational Resources Information Center

    Johnson, Robert E.; Liddell, Scott K.

    2011-01-01

    In this article we describe a componential, articulatory approach to the phonetic description of the configuration of the four fingers. Abandoning the traditional holistic, perceptual approach, we propose a system of notational devices and distinctive features for the description of the four fingers proper (index, middle, ring, and pinky).…

  4. Rediscovering Ruth Faison Shaw and Her Finger-Painting Method

    ERIC Educational Resources Information Center

    Mayer, Veronica

    2005-01-01

    Ruth Faison Shaw was an art educator who developed a nontraditional educational perspective of teaching and a different vision about children's art. As such, she is considered by some to be the initiator of finger-painting in America (The History of Art Education Timeline 1930-1939, 2002.) Shaw developed the technique of finger-painting and a…

  5. Robust Finger Vein ROI Localization Based on Flexible Segmentation

    PubMed Central

    Lu, Yu; Xie, Shan Juan; Yoon, Sook; Yang, Jucheng; Park, Dong Sun

    2013-01-01

    Finger veins have been proved to be an effective biometric for personal identification in the recent years. However, finger vein images are easily affected by influences such as image translation, orientation, scale, scattering, finger structure, complicated background, uneven illumination, and collection posture. All these factors may contribute to inaccurate region of interest (ROI) definition, and so degrade the performance of finger vein identification system. To improve this problem, in this paper, we propose a finger vein ROI localization method that has high effectiveness and robustness against the above factors. The proposed method consists of a set of steps to localize ROIs accurately, namely segmentation, orientation correction, and ROI detection. Accurate finger region segmentation and correct calculated orientation can support each other to produce higher accuracy in localizing ROIs. Extensive experiments have been performed on the finger vein image database, MMCBNU_6000, to verify the robustness of the proposed method. The proposed method shows the segmentation accuracy of 100%. Furthermore, the average processing time of the proposed method is 22 ms for an acquired image, which satisfies the criterion of a real-time finger vein identification system. PMID:24284769

  6. Population Structure and Diversity in Finger Millet (Eleusine coracana) Germplasm.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A genotypic analysis of 79 finger millet accessions (E. coracana subsp. coracana) from 11 African and 5 Asian countries, plus 14 wild E. coracana subsp. africana lines collected in Uganda and Kenya was conducted with 45 SSR markers distributed across the finger millet genome. Phylogenetic and popula...

  7. Finger vein extraction using gradient normalization and principal curvature

    NASA Astrophysics Data System (ADS)

    Choi, Joon Hwan; Song, Wonseok; Kim, Taejeong; Lee, Seung-Rae; Kim, Hee Chan

    2009-02-01

    Finger vein authentication is a personal identification technology using finger vein images acquired by infrared imaging. It is one of the newest technologies in biometrics. Its main advantage over other biometrics is the low risk of forgery or theft, due to the fact that finger veins are not normally visible to others. Extracting finger vein patterns from infrared images is the most difficult part in finger vein authentication. Uneven illumination, varying tissues and bones, and changes in the physical conditions and the blood flow make the thickness and brightness of the same vein different in each acquisition. Accordingly, extracting finger veins at their accurate positions regardless of their thickness and brightness is necessary for accurate personal identification. For this purpose, we propose a new finger vein extraction method which is composed of gradient normalization, principal curvature calculation, and binarization. As local brightness variation has little effect on the curvature and as gradient normalization makes the curvature fairly uniform at vein pixels, our method effectively extracts finger vein patterns regardless of the vein thickness or brightness. In our experiment, the proposed method showed notable improvement as compared with the existing methods.

  8. Coordination of bowing and fingering in violin playing.

    PubMed

    Baader, Andreas P; Kazennikov, Oleg; Wiesendanger, Mario

    2005-05-01

    Playing string instruments implies motor skills including asymmetrical interlimb coordination. How special is musical skill as compared to other bimanually coordinated, non-musical skillful performances? We succeeded for the first time to measure quantitatively bimanual coordination in violinists playing repeatedly a simple tone sequence. A motion analysis system was used to record finger and bow trajectories for assessing the temporal structure of finger-press, finger-lift (left hand), and bow stroke reversals (right arm). The main results were: (1) fingering consisted of serial and parallel (anticipatory) mechanisms; (2) synchronization between finger and bow actions varied from -12 ms to 60 ms, but these 'errors' were not perceived. The results suggest that (1) bow-finger synchronization varied by about 50 ms from perfect simultaneity, but without impairing auditory perception; (2) the temporal structure depends on a number of combinatorial mechanisms of bowing and fingering. These basic mechanisms were observed in all players, including all amateurs. The successful biomechanical measures of fingering and bowing open a vast practical field of assessing motor skills. Thus, objective assessment of larger groups of string players with varying musical proficiency, or of professional string players developing movement disorders, may be helpful in music education. PMID:15820650

  9. Finger vein image quality evaluation using support vector machines

    NASA Astrophysics Data System (ADS)

    Yang, Lu; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2013-02-01

    In an automatic finger-vein recognition system, finger-vein image quality is significant for segmentation, enhancement, and matching processes. In this paper, we propose a finger-vein image quality evaluation method using support vector machines (SVMs). We extract three features including the gradient, image contrast, and information capacity from the input image. An SVM model is built on the training images with annotated quality labels (i.e., high/low) and then applied to unseen images for quality evaluation. To resolve the class-imbalance problem in the training data, we perform oversampling for the minority class with random-synthetic minority oversampling technique. Cross-validation is also employed to verify the reliability and stability of the learned model. Our experimental results show the effectiveness of our method in evaluating the quality of finger-vein images, and by discarding low-quality images detected by our method, the overall finger-vein recognition performance is considerably improved.

  10. A new algorithmic approach for fingers detection and identification

    NASA Astrophysics Data System (ADS)

    Mubashar Khan, Arslan; Umar, Waqas; Choudhary, Taimoor; Hussain, Fawad; Haroon Yousaf, Muhammad

    2013-03-01

    Gesture recognition is concerned with the goal of interpreting human gestures through mathematical algorithms. Gestures can originate from any bodily motion or state but commonly originate from the face or hand. Hand gesture detection in a real time environment, where the time and memory are important issues, is a critical operation. Hand gesture recognition largely depends on the accurate detection of the fingers. This paper presents a new algorithmic approach to detect and identify fingers of human hand. The proposed algorithm does not depend upon the prior knowledge of the scene. It detects the active fingers and Metacarpophalangeal (MCP) of the inactive fingers from an already detected hand. Dynamic thresholding technique and connected component labeling scheme are employed for background elimination and hand detection respectively. Algorithm proposed a new approach for finger identification in real time environment keeping the memory and time constraint as low as possible.

  11. Bulk elastic fingering in soft materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Bouchaud, Elisabeth; Mahadevan, L.; Harvard University Team; Ec2M/Espci Collaboration; Cambridge University Collaboration

    2014-11-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. A systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. A very important feature is that elasticity doesn't influence this lengthscale, making this instability very generic. We will also show some new results about an elastic counterpart experiment of the famous Saffman-Taylor experiment, where we push a soft gel in a stiff one.

  12. Task specificity of finger dexterity tests.

    PubMed

    Berger, Monique A M; Krul, Arno J; Daanen, Hein A M

    2009-01-01

    Finger dexterity tests are generally used to assess performance decrease due to gloves, cold and pathology. It is generally assumed that the O'Connor and Purdue Pegboard test yield similar results. In this experiment we compared these two tests for dry conditions without gloves, and for dry and wet conditions with two types of Nytril gloves. In line with previous observations, wearing gloves caused a decrease in performance of about 12% for the O'Connor test and 9% for the Purdue test. Wetting the gloves prior to the test had no effect on the Purdue score. However, wetting the gloves increased the O'Connor performance significantly by 11%. The results show that the O'Connor and Purdue tests do not yield similar results and should be used selectively for specific tasks. PMID:18339353

  13. Bulk Elastic Fingering in Soft Materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Mora, Serge; Mahadevan, L.; Bouchaud, Elisabeth; Harvard University Team; Espci-Paristech Collaboration; Cambridge University Collaboration; Montpellier 2 University Collaboration

    2015-03-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. A systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. A very important feature is that elasticity doesn't influence this lengthscale, making this instability very generic. We will also show some new results about an elastic counterpart experiment of the famous Saffman-Taylor experiment, where we push a soft gel in a stiff one.

  14. Mechanics of finger-tip electronics

    NASA Astrophysics Data System (ADS)

    Su, Yewang; Li, Rui; Cheng, Huanyu; Ying, Ming; Bonifas, Andrew P.; Hwang, Keh-Chih; Rogers, John A.; Huang, Yonggang

    2013-10-01

    Tactile sensors and electrotactile stimulators can provide important links between humans and virtual environments, through the sensation of touch. Soft materials, such as low modulus silicones, are attractive as platforms and support matrices for arrays sensors and actuators that laminate directly onto the fingertips. Analytic models for the mechanics of three dimensional, form-fitting finger cuffs based on such designs are presented here, along with quantitative validation using the finite element method. The results indicate that the maximum strains in the silicone and the embedded devices are inversely proportional to the square root of radius of curvature of the cuff. These and other findings can be useful in formulating designs for these and related classes of body-worn, three dimensional devices.

  15. Surface Tension and Fingering of Miscible Interfaces

    NASA Technical Reports Server (NTRS)

    Abib, Mohammed; Liu, Jian-Bang; Ronney, Paul D.

    1999-01-01

    Experiments on miscible, buoyantly unstable reaction-diffusion fronts and non-reacting displacement fronts in Hele-Shaw cells show a fingering-type instability whose wavelengths (lambda*) are consistent with an interfacial tension (sigma) at the front caused by the change in chemical composition, even though the solutions are miscible in all proportions. In conjunction with the Saffman-Taylor model, the relation sigma = K/tau, where tau is the interface thickness and K approximately equal 4 +/- 2 x 10(exp -6) dyne, enables prediction of our measured values of lambda* as well as results from prior experiments on miscible interfaces. These results indicate that even for miscible fluids, surface tension is generally a more significant factor than diffusion in interfacial stability and flow characteristics.

  16. Joint lubrication.

    PubMed

    McCutchen, C W

    1983-01-01

    The fine-pored, easily compressed articular cartilage provides animal joints with self-pressurized hydrostatic (weeping) lubrication. The solid skeletons of the cartilages press against each other, but so lightly that their rubbing is lubricated successfully by synovial fluid--a boundary lubricant too weak to lubricate ordinary bearings. PMID:6317095

  17. Colloidal Transport and Periodic Stick-Slip Motion in Cholesteric Finger Textures

    NASA Astrophysics Data System (ADS)

    Chen, Kui; Metcalf, Linnea; Reich, Daniel H.; Leheny, Robert L.

    2014-03-01

    We have investigated the transport of colloidal particles within cholesteric finger textures formed by mixtures of the nematic liquid crystal 4-cyano-4'-pentylbiphenyl (5CB) and the chiral dopant4-(2-methylbutyl)-4-cyanobiphenyl (CB15) with cholesteric pitches between 24 and 55 micrometers. Spherical silica colloids (radius 5-10 micrometers) moving under the force of gravity through the texture translated strictly perpendicular to the cholesteric axis and had no measurable mobility parallel to the axis. Thus, when the applied force was oriented at an oblique angle to the axis, the spheres moved at an angle to the force. Nickel disks, 20 micrometers in radius and 300 nanometers thick, driven by gravity similarly showed no mobility parallel to the cholesteric axis for small pitch. For larger pitch, the disks displayed a periodic stick-slip motion caused by elastic retardation followed by yielding of the finger texture. Effective drag viscosities obtained from the sphere and disk motion were anomalously large compared with those of pure 5CB.

  18. Study on the Constitutive Model for Jointed Rock Mass

    PubMed Central

    Xu, Qiang; Chen, Jianyun; Li, Jing; Zhao, Chunfeng; Yuan, Chenyang

    2015-01-01

    A new elasto-plastic constitutive model for jointed rock mass, which can consider the persistence ratio in different visual angle and anisotropic increase of plastic strain, is proposed. The proposed the yield strength criterion, which is anisotropic, is not only related to friction angle and cohesion of jointed rock masses at the visual angle but also related to the intersection angle between the visual angle and the directions of the principal stresses. Some numerical examples are given to analyze and verify the proposed constitutive model. The results show the proposed constitutive model has high precision to calculate displacement, stress and plastic strain and can be applied in engineering analysis. PMID:25885695

  19. Moment-knee angle relation in well trained athletes.

    PubMed

    Ullrich, B; Brueggemann, G P

    2008-08-01

    The purpose of this work was to investigate whether different modes of long-term competitive physical activity cause functional differences in the moment-knee angle relation of the M. quadriceps femoris (QF). Therefore, a sample (n = 40) of young male competitive endurance runners, cyclists, triathletes and tennis players performed isometric maximal voluntary knee extensions (MVC) with their stronger leg at six different knee joint angles while keeping the hip joint angle constant. Muscle activation of QF-muscles during MVC was estimated using surface electromyography (EMG). Moments and EMG data of each subject were normalized to the largest value produced at any knee joint position [% Max.]. No significant differences in the normalized [% Max.] moment-knee angle relation of the QF were found between endurance runners, cyclists and triathletes. Despite few unsystematic exceptions, no functional differences in the normalized moment-knee angle relation of the QF occurred among tennis players and the endurance-oriented athletic groups. Obtained by curve fitting, the optimal knee joint angle for moment production was not significantly different among all athletic groups. We conclude that long-term competitive endurance running, cycling, triathlon and tennis do not provoke functional differences in the moment-knee angle relation of the whole QF. PMID:18050053

  20. Finger movements and fingers postures in pre-term infants are not a good indicator of brain damage.

    PubMed

    Konishi, Y; Prechtl, H F

    1994-02-01

    The aim of the study was to analyse, with a more detailed classification the occurrence of movements and postures of the fingers in normal and brain damaged pre-term infants. To this end the same videorecordings of normal subjects of the study described by Cioni and Prechtl and those with defined brain lesions from the investigation by Ferrari et al. have been reanalysed. In three general movements, selected randomly from each infant, we assessed the finger movement. There was no systematic trend with age and the repertoire of finger patterns per observation varied between different individuals. Only one or two finger(s) move (pattern B) and synchronized finger opening-closing (pattern D) and the complex and variable movement of three or more fingers (pattern E) are all more often or even only seen during arm movements. Fisting without arm movement (pattern A-) was only seen less frequently in the control cases, in the infants with flares and one-sided lesions. On the other hand, the two latter groups had more often pattern C+ (opening of all fingers with arm movement) while B+ (only one or two fingers move with arm movement) and E+ (three or more fingers move variably with arm movement) was less frequent in the severely damaged infants. Albeit significant differences, the plotted data immediately show the large overlap of the findings between the groups. There was no difference in the fisting between low-risk and neurologically abnormal pre-term infants. These findings corroborate the conclusions that abnormal movements and postures are not useful in the diagnosis of pre-term infants with confirmed brain lesions because of the wide overlap between the values for normal and brain damaged infants. PMID:8200324

  1. Fluctuations in Saffman-Taylor fingers with quenched disorder

    NASA Astrophysics Data System (ADS)

    Torralba, M.; Ortín, J.; Hernández-Machado, A.; Corvera Poiré, E.

    2006-04-01

    We make an experimental characterization of the effect that static disorder has on the shape of a normal Saffman-Taylor finger. We find that static noise induces a small amplitude and long wavelength instability on the sides of the finger. Fluctuations on the finger sides have a dominant wavelength, indicating that the system acts as a selective amplifier of static noise. The dominant wavelength does not seem to be very sensitive to the intensity of static noise present in the system. On the other hand, at a given flow rate, rms fluctuations of the finger width, decrease with decreasing intensity of static noise. This might explain why the sides of the fingers are flat for typical Saffman-Taylor experiments. Comparison with previous numerical studies of the effect that temporal noise has on the Saffman-Taylor finger, leads to conclude that the effect of temporal noise and static noise are similar. The behavior of fluctuations of the finger width found in our experiments, is qualitatively similar to one recently reported, in the sense that, the magnitude of the width fluctuations decays as a power law of the capillary number, at low flow rates, and increases with capillary number for larger flow rates.

  2. Joint assembly

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2010-01-01

    A joint assembly is provided which includes a drive assembly and a swivel mechanism. The drive assembly features a motor operatively associated with a plurality of drive shafts for driving auxiliary elements, and a plurality of swivel shafts for pivoting the drive assembly. The swivel mechanism engages the swivel shafts and has a fixable element that may be attached to a foundation. The swivel mechanism is adapted to cooperate with the swivel shafts to pivot the drive assembly with at least two degrees of freedom relative to the foundation. The joint assembly allows for all components to remain encased in a tight, compact, and sealed package, making it ideal for space, exploratory, and commercial applications.

  3. Dendrites, viscous fingers, and the theory of pattern formation

    NASA Technical Reports Server (NTRS)

    Langer, J. S.

    1989-01-01

    Recent developments in the theory of pattern formation in dendritic crystal growth and viscous fingering in fluids are reviewed. Consideration is given to the discovery that weak capillary forces act as singular perturbations which lead to selection mechanisms in dendritic crystal growth and fingering patterns. Other topics include the conventional thermodynamic model of the solidification of a pure substance from its melt, fingering instability, pattern selection, the solvability theory, dendritic growth rates, the bubble effect discovered by Couder et al. (1986), the dynamics of pattern-forming systems, and snowflake formation.

  4. Narrow fingers in the Saffman-Taylor instability

    NASA Astrophysics Data System (ADS)

    Couder, Y.; Gerard, N.; Rabaud, M.

    1986-12-01

    Saffman-Taylor fingers with a relative width much smaller than the classical limit lambda = 0.5 are found when a small isolated bubble is located at their tip. These solutions are members of a family found by Saffman and Taylor (1958) neglecting superficial tension. Recent theories have shown that when capillary forces are taken into account an unphysical cusplike singularity would appear at the tip of all the fingers with lambda less than 0.5. Conversely, here the replacement of the tip by a small bubble makes these solutions possible. At large velocity these fingers show dendritic instability.

  5. Finger rafting: a generic instability of floating elastic sheets.

    PubMed

    Vella, Dominic; Wettlaufer, J S

    2007-02-23

    Colliding ice floes are often observed to form a series of interlocking fingers. We show that this striking phenomenon is not a result of some peculiar property of ice but rather a general and robust mechanical phenomenon reproducible in the laboratory with other floating materials. We determine the theoretical relationship between the width of the resulting fingers and the material's mechanical properties and present experimental results along with field observations to support the theory. The generality of this "finger rafting" suggests that analogous processes may be responsible for creating the large-scale structures observed at the boundaries between Earth's convergent tectonic plates. PMID:17359135

  6. A hierarchical classification method for finger knuckle print recognition

    NASA Astrophysics Data System (ADS)

    Kong, Tao; Yang, Gongping; Yang, Lu

    2014-12-01

    Finger knuckle print has recently been seen as an effective biometric technique. In this paper, we propose a hierarchical classification method for finger knuckle print recognition, which is rooted in traditional score-level fusion methods. In the proposed method, we firstly take Gabor feature as the basic feature for finger knuckle print recognition and then a new decision rule is defined based on the predefined threshold. Finally, the minor feature speeded-up robust feature is conducted for these users, who cannot be recognized by the basic feature. Extensive experiments are performed to evaluate the proposed method, and experimental results show that it can achieve a promising performance.

  7. Flexor Tendon Entrapment at the Malunited Base Fracture of the Proximal Phalanx of the Finger in Child: A Case Report.

    PubMed

    Lee, Young-Keun; Park, Soojin; Lee, Malrey

    2015-09-01

    The proximal phalangeal base is the most commonly fractured hand bone in children. Such fractures are rarely reported as irreducible due to flexor tendon entrapment. Here, we describe a patient who sustained a malunited fracture on the right fifth finger proximal phalanx with flexor tendon entrapment after treatment with closed reduction with K-wires fixation.A 13-year-old patient came to the clinic following a bicycle accident 6 weeks ago. He presented with flexion limitation in his small finger on the right hand. During physical examination, the patient felt no pain, and the neurovascular structures were intact. However range of motion (ROM) in his small finger was not normal. Plain radiographs displayed a Salter-Harris type II fracture of the small finger proximal phalanx base and volar angulation with callus formation. During the operation, it was established that the flexor digitorum superficialis (FDS) around the fracture had a severe adhesion, whereas the flexor digitorum profundus (FDP) was entrapped between the volarly displaced metaphyses and the epiphyses and united with the bone. We removed the volarly displaced metaphyses and freed FDP and repaired the A2 pulley. The bone was anatomically fixed with K-wires. In the treatment after the operation, on the 2nd day, the patient was permitted the DIP joint motion by wearing a dynamic splint.At the 12-months follow-up, the patient had regained full ROM with no discomfort and the proximal phalanx growth plate of the small finger closed naturally with normal alignment.When treating a proximal phalangeal base fracture in children, the possibility of flexor tendon entrapment should be considered and should be carefully dealt with in its treatment. PMID:26334897

  8. Fifth finger camptodactyly maps to chromosome 3q11.2-q13.12 in a large German kindred.

    PubMed

    Malik, Sajid; Schott, Jörg; Schiller, Julia; Junge, Anna; Baum, Erika; Koch, Manuela C

    2008-02-01

    Camptodactyly (MIM 114200) is a digit deformity characterised by permanent flexion contracture of fifth fingers at the proximal interphalangeal (PIP) joints. The sporadic cases are common but a familial occurrence is not much appreciated. In an attempt to identify the genetic basis of camptodactyly, we have analysed a large German family with camptodactyly segregating in an autosomal dominant fashion. The affected family members exhibited clinical features of fifth finger camptodactyly and knuckle pads on the crooked fifth finger and on fingers 2-3. Typically, women were more severely affected than men. Microsatellite analyses of five candidate loci known to be associated with camptodactyly-like phenotypes did not show co-segregation with the phenotype in our family. A genome-wide linkage scan using a total of 414 microsatellite markers gave significant evidence of linkage between the familial phenotype and chromosomal locus 3q11.2-q13.12 (maximum two-point LOD score 3.04). The key recombination events showed that the phenotype localises between markers D3S2465 and D3S3044, spanning an interval of approximately 15 cM. This study reports the first genetic locus linked to isolated autosomal dominant fifth finger camptodactyly with knuckle pads and proves the hypothesis that camptodactyly is distinct from camptodactyly-associated phenotypes including Dupuytren contracture. Additional studies of other families will be necessary to determine the existence of genetic homogeneity or heterogeneity of the anomaly and to narrow down the genetic interval to identify the responsible gene. Since genetic heterogeneity for isolated camptodactyly is likely, we propose to designate the 3q11.2-q13.12 locus as CAMPD1 (ie, camptodactyly 1). PMID:18000522

  9. Limited joint mobility syndrome in diabetes mellitus: A minireview

    PubMed Central

    Gerrits, Esther G; Landman, Gijs W; Nijenhuis-Rosien, Leonie; Bilo, Henk J

    2015-01-01

    Limited joint mobility syndrome (LJMS) or diabetic cheiroarthropathy is a long term complication of diabetes mellitus. The diagnosis of LJMS is based on clinical features: progression of painless stiffness of hands and fingers, fixed flexion contractures of the small hand and foot joints, impairment of fine motion and impaired grip strength in the hands. As the syndrome progresses, it can also affect other joints. It is important to properly diagnose such a complication as LJMS. Moreover, it is important to diagnose LJMS because it is known that the presence of LJMS is associated with micro- and macrovascular complications of diabetes. Due to the lack of curative treatment options, the suggested method to prevent or decelerate the development of LJMS is improving or maintaining good glycemic control. Daily stretching excercises of joints aim to prevent or delay progression of joint stiffness, may reduce the risk of inadvertent falls and will add to maintain quality of life. PMID:26265997

  10. Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects

    PubMed Central

    Brorsson, Sofia; Nilsdotter, Anna; Hilliges, Marita; Sollerman, Christer; Aurell, Ylva

    2008-01-01

    Background The aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements. Methods M. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35–73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device. Results The following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm3 and in women 16.6 cm3. The mean CSA was 2.54 cm2 for men and 1.84 cm2 for women. The mean pennation angle for men was 6.5° and for women 5.5°. The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force. Conclusion Ultrasound is a useful tool

  11. Solar angle reference manual

    SciTech Connect

    Sibson, R.

    1983-01-01

    The introduction is the only text in the volume; the rest of the book contains easy-to-use graphical methods for building design and construction using solar energy. Isogonic charts and solar angle diagrams are included. Isogonic charts. Solar angle diagrams.

  12. Reading Angles in Maps

    ERIC Educational Resources Information Center

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  13. In vivo human knee joint dynamic properties as functions of muscle contraction and joint position.

    PubMed

    Zhang, L Q; Nuber, G; Butler, J; Bowen, M; Rymer, W Z

    1998-01-01

    Information on the dynamic properties (joint stiffness, viscosity and limb inertia) of the human knee joint is scarce in the literature, especially for actively contracting knee musculature. A joint driving device was developed to apply small-amplitude random perturbations to the human knee at several flexion angles with the subject maintaining various levels of muscle contraction. It was found that joint stiffness and viscosity increased with muscle contraction substantially, while limb inertia was constant. Stiffness produced by the quadriceps was highest at 30 degrees flexion and decreased with increasing or decreasing flexion angle, while knee flexors produced highest stiffness at 90 degree flexion. When knee flexion was < 60 degrees, stiffness produced by the quadriceps was higher than that of the hamstrings and gastrocnemius at the same level of background muscle torque, while knee flexor muscles produced higher stiffnesses than the quadriceps at 90 degree flexion. Similar but less obvious trends were observed for joint viscosity. Passive joint stiffness at full knee extension was significantly higher than in more flexed positions. Surprisingly, as the knee joint musculature changed from relaxed to contracting at 50% MVC, system damping ratio remained at about 0.2. This outcome potentially simplifies neuromuscular control of the knee joint. In contrast, the natural undamped frequency increased more than twofold, potentially making the knee joint respond more quickly to the central nervous system commands. The approach described here provides us with a potentially valuable tool to quantify in vivo dynamic properties of normal and pathological human knee joints. PMID:9596540

  14. Examiner's finger-mounted fetal tissue oximetry

    NASA Astrophysics Data System (ADS)

    Kanayama, Naohiro; Niwayama, Masatsugu

    2014-06-01

    The best way to assess fetal condition is to observe the oxygen status of the fetus (as well as to assess the condition of infants, children, and adults). Previously, several fetal oximeters have been developed; however, no instrument has been utilized in clinical practice because of the low-capturing rate of the fetal oxygen saturation. To overcome the problem, we developed a doctor's finger-mounted fetal tissue oximeter, whose sensor volume is one hundredth of the conventional one. Additionally, we prepared transparent gloves. The calculation algorithm of the hemoglobin concentration was derived from the light propagation analysis based on the transport theory. We measured neonatal and fetal oxygen saturation (StO2) with the new tissue oximeter. Neonatal StO was measured at any position of the head regardless of amount of hair. Neonatal StO was found to be around 77%. Fetal StO was detected in every position of the fetal head during labor regardless of the presence of labor pain. Fetal StO without labor pain was around 70% in the first stage of labor and around 60% in the second stage of labor. We concluded that our new concept of fetal tissue oximetry would be useful for detecting fetal StO in any condition of the fetus.

  15. Finger cold-induced vasodilation: a review.

    PubMed

    Daanen, H A M

    2003-06-01

    Cold-induced vasodilation (CIVD) in the finger tips generally occurs 5-10 min after the start of local cold exposure of the extremities. This phenomenon is believed to reduce the risk of local cold injuries. However, CIVD is almost absent during hypothermia, when survival of the organism takes precedence over the survival of peripheral tissue. Subjects that are often exposed to local cold (e.g. fish filleters) develop an enhanced CIVD response. Also, differences between ethnic groups are obvious, with black people having the weakest CIVD response. Many other factors affect CIVD, such as diet, alcohol consumption, altitude, age and stress. CIVD is probably caused by a sudden decrease in the release of neurotransmitters from the sympathetic nerves to the muscular coat of the arterio-venous anastomoses (AVAs) due to local cold. AVAs are specific thermoregulatory organs that regulate blood flow in the cold and heat. Their relatively large diameter enables large amounts of blood to pass and convey heat to the surrounding tissue. Unfortunately, information on the quantity of AVAs is lacking, which makes it difficult to estimate the full impact on peripheral blood flow. This review illustrates the thermospecificity of the AVAs and the close link to CIVD. CIVD is influenced by many parameters, but controlled experiments yield information on how CIVD protects the extremities against cold injuries. PMID:12712346

  16. Finger Length Ratios in Serbian Transsexuals

    PubMed Central

    Vujović, Svetlana; Popović, Srdjan; Mrvošević Marojević, Ljiljana; Ivović, Miomira; Tančić-Gajić, Milina; Stojanović, Miloš; Marina, Ljiljana V.; Barać, Marija; Barać, Branko; Kovačević, Milena; Duišin, Dragana; Barišić, Jasmina; Djordjević, Miroslav L.; Micić, Dragan

    2014-01-01

    Atypical prenatal hormone exposure could be a factor in the development of transsexualism. There is evidence that the 2nd and 4th digit ratio (2D : 4D) associates negatively with prenatal testosterone and positively with estrogens. The aim was to assess the difference in 2D : 4D between female to male transsexuals (FMT) and male to female transsexuals (MFT) and controls. We examined 42 MFT, 38 FMT, and 45 control males and 48 control females. Precise measurements were made by X-rays at the ventral surface of both hands from the basal crease of the digit to the tip using vernier calliper. Control male and female patients had larger 2D : 4D of the right hand when compared to the left hand. Control male's left hand ratio was lower than in control female's left hand. There was no difference in 2D : 4D between MFT and control males. MFT showed similar 2D : 4D of the right hand with control women indicating possible influencing factor in embryogenesis and consequently finger length changes. FMT showed the lowest 2D : 4D of the left hand when compared to the control males and females. Results of our study go in favour of the biological aetiology of transsexualism. PMID:24982993

  17. Ubiquitin interactions of NZF zinc fingers

    PubMed Central

    Alam, Steven L; Sun, Ji; Payne, Marielle; Welch, Brett D; Blake, B Kelly; Davis, Darrell R; Meyer, Hemmo H; Emr, Scott D; Sundquist, Wesley I

    2004-01-01

    Ubiquitin (Ub) functions in many different biological pathways, where it typically interacts with proteins that contain modular Ub recognition domains. One such recognition domain is the Npl4 zinc finger (NZF), a compact zinc-binding module found in many proteins that function in Ub-dependent processes. We now report the solution structure of the NZF domain from Npl4 in complex with Ub. The structure reveals that three key NZF residues (13TF14/M25) surrounding the zinc coordination site bind the hydrophobic ‘Ile44' surface of Ub. Mutations in the 13TF14/M25 motif inhibit Ub binding, and naturally occurring NZF domains that lack the motif do not bind Ub. However, substitution of the 13TF14/M25 motif into the nonbinding NZF domain from RanBP2 creates Ub-binding activity, demonstrating the versatility of the NZF scaffold. Finally, NZF mutations that inhibit Ub binding by the NZF domain of Vps36/ESCRT-II also inhibit sorting of ubiquitylated proteins into the yeast vacuole. Thus, the NZF is a versatile protein recognition domain that is used to bind ubiquitylated proteins during vacuolar protein sorting, and probably many other biological processes. PMID:15029239

  18. From frictional fingers to stick slip bubbles

    NASA Astrophysics Data System (ADS)

    Sandnes, Bjørnar; Jørgen Måløy, Knut; Flekkøy, Eirik; Eriksen, Jon

    2014-05-01

    Gas intrusion into wet porous/deformable/granular media occurs in a wide range of natural and engineered settings. Examples include hydrocarbon recovery, carbon dioxide geo-sequestration, gas venting in sediments and volcanic eruptions. In the case where the intruding gas is able to displace particles and grains, local changes in granular packing fraction govern the evolution of flow paths, resulting in complex pattern formation of the displacement flow. Here we investigate flow patterning as a compressed gas displaces a granular mixture confined in the narrow gap of a Hele-Shaw cell. We find a surprising variety of different pattern formation dynamics, and present a unified phase diagram of the flow morphologies we observe. This talk will focus on one particular transition the system undergoes: from frictional fingers to stick slip bubbles. We show that the frictional fluid flow patterns depend on granular mass loading and system elasticity, analogous to the behaviour of the well-known spring-block sliding friction problem.

  19. Development of Functional Recovery Training Device for Hemiplegic Fingers with Finger-expansion Facilitation Exercise by Stretch Reflex

    NASA Astrophysics Data System (ADS)

    Yu, Yong; Iwashita, Hisashi; Kawahira, Kazumi; Hayashi, Ryota

    This paper develops a functional recovery training device to perform repetition facilitating exercise for hemiplegic finger rehabilitation. On the facilitation exercise, automatic finger expansion can be realized and facilitated by stretch reflex, where a stimulation forces is applied instantaneously on flexion finger for making strech reflex and resistance forces are applied for maintaining the strech reflex. In this paper, novel parallel mechanisms, force sensing system with high sensitivity and resistance accompanying cooperation control method are proposed for sensing, controlling and realizing the stimulation force, resistance forces, strech reflex and repetition facilitating exercise. The effectivities and performances of the device are shown by some experiments.

  20. The generation of zinc finger proteins by modular assembly

    PubMed Central

    Bhakta, Mital; Segal, David J.

    2015-01-01

    The modular assembly (MA) method of generating engineered zinc finger proteins (ZFPs) was the first practical method for creating custom DNA-binding proteins. As such, MA has enabled a vast exploration of sequence-specific methods and reagents, ushering in the modern era of zinc finger-based applications that are described in this volume. The first zinc finger nuclease to cleave an endogenous site was created using MA, as was the first artificial transcription factor to enter phase II clinical trials. In recent years, other excellent methods have been developed that improved the affinity and specificity of the engineered ZFPs. However, MA is still used widely for many applications. This chapter will describe methods and give guidance for the creation of ZFPs using MA. Such ZFPs might be useful as starting materials to perform other methods described in this volume. Here, we also describe a single-strand annealing recombination assay for the initial testing of zinc finger nucleases. PMID:20680825

  1. L'index significant (The Pointed Index Finger).

    ERIC Educational Resources Information Center

    Calbris, G.

    1979-01-01

    In the framework of a study of nonverbal communication, the various meanings attached to the pointed index finger are analyzed. The question is raised as to what extent the findings hold for cultures other than French. (AMH)

  2. Seal finger: A case report and review of the literature

    PubMed Central

    White, Colin P; Jewer, David D

    2009-01-01

    A recent case of seal finger which was misdiagnosed and hence mistreated at the patient’s first presentation is described. The patient was eventually referred to a hand specialist and after the correct treatment with tetracycline, responded well without any long-term sequelae. Seal finger is an occupational injury that occurs to those who work directly or indirectly with seals. The disease entity has been described in both Scandinavian and Canadian literature. The causative microorganism was unknown until 1991, when Mycoplasma phocacerebrale was isolated from both the finger of a patient with seal finger and from the mouth of a seal that bit the patient. Although rare, the disease is not uncommon in marine workers, biologists and veterinarians. Prompt identification based on patient history and treatment with oral tetracycline is pendant to a favourable patient outcome. PMID:21119845

  3. Finger vein recognition based on local directional code.

    PubMed

    Meng, Xianjing; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2012-01-01

    Finger vein patterns are considered as one of the most promising biometric authentication methods for its security and convenience. Most of the current available finger vein recognition methods utilize features from a segmented blood vessel network. As an improperly segmented network may degrade the recognition accuracy, binary pattern based methods are proposed, such as Local Binary Pattern (LBP), Local Derivative Pattern (LDP) and Local Line Binary Pattern (LLBP). However, the rich directional information hidden in the finger vein pattern has not been fully exploited by the existing local patterns. Inspired by the Webber Local Descriptor (WLD), this paper represents a new direction based local descriptor called Local Directional Code (LDC) and applies it to finger vein recognition. In LDC, the local gradient orientation information is coded as an octonary decimal number. Experimental results show that the proposed method using LDC achieves better performance than methods using LLBP. PMID:23202194

  4. Finger Vein Recognition Based on Local Directional Code

    PubMed Central

    Meng, Xianjing; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2012-01-01

    Finger vein patterns are considered as one of the most promising biometric authentication methods for its security and convenience. Most of the current available finger vein recognition methods utilize features from a segmented blood vessel network. As an improperly segmented network may degrade the recognition accuracy, binary pattern based methods are proposed, such as Local Binary Pattern (LBP), Local Derivative Pattern (LDP) and Local Line Binary Pattern (LLBP). However, the rich directional information hidden in the finger vein pattern has not been fully exploited by the existing local patterns. Inspired by the Webber Local Descriptor (WLD), this paper represents a new direction based local descriptor called Local Directional Code (LDC) and applies it to finger vein recognition. In LDC, the local gradient orientation information is coded as an octonary decimal number. Experimental results show that the proposed method using LDC achieves better performance than methods using LLBP. PMID:23202194

  5. Finger Growth in Surfactant Solution in Hele-Shaw Cells

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takehiro; Yamashita, Atsushi; Nakamura, Yousuke; Hashimoto, Takamasa; Mori, Noriyasu

    2006-05-01

    Viscous fingering in surfactant solutions was experimentally studied. Aqueous solutions of cetyltrimethylammonium bromide (CTAB) with sodium salicylate (NaSal) as a counter ion were used as test fluids. Excess of counter ion was added into a surfactant solution of CTAB to configure network structures of wormlike micelles. The experiments were mainly carried out using a square Hele-Shaw cell. The structure of fingering pattern was dimensionally analyzed to classify the patterns into three types. In addition, growth phenomena distinguishing for the viscous finger in the CTAB/NaSal solutions were observed: surface instabilities with dendrites, and a sudden protrusion from a cuspidate shaped finger tip. The dependence of the sudden protrusion on the shear rate was confirmed by the experiment using a rectangular cell.

  6. Suppression of viscous fingering in nonflat Hele-Shaw cells.

    PubMed

    Brandão, Rodolfo; Fontana, João V; Miranda, José A

    2014-11-01

    Viscous fingering formation in flat Hele-Shaw cells is a classical and widely studied fluid mechanical problem. Recently, instead of focusing on the development of the fingering instability, researchers have devised different strategies aiming to suppress its appearance. In this work, we study a protocol that intends to inhibit the occurrence of fingering instabilities in nonflat (spherical and conical) Hele-Shaw cell geometries. By using a mode-coupling theory to describe interfacial evolution, plus a variational controlling technique, we show that viscous fingering phenomena can be minimized in such a confined, curved environment by properly manipulating a time-dependent injection flow rate Q(t). Explicit expressions for Q(t) are derived for the specific cases of spherical and conical cells. The suitability of the controlling method is verified for linear and weakly nonlinear stages of the flow. PMID:25493877

  7. The effects of vibration-reducing gloves on finger vibration

    PubMed Central

    Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

    2015-01-01

    Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration can cause hand-arm vibration syndrome. Vibration-reducing gloves have been used as an alternative approach to reduce the vibration exposure. However, their effectiveness for reducing finger-transmitted vibrations remains unclear. This study enhanced the understanding of the glove effects on finger vibration and provided useful information on the effectiveness of typical VR gloves at reducing the vibration transmitted to the fingers. The new

  8. Fingered bola body, bola with same, and methods of use

    NASA Technical Reports Server (NTRS)

    Dzenitis, John M. (Inventor); Billica, Linda W. (Inventor)

    1994-01-01

    The present invention discloses bola bodies, bolas, and a snaring method which makes use such devices. A bola body, according to the present invention, is nonspherical or irregular in shape rather than a smooth sphere or ovoid body. One or more fingers extends from the bola body. These fingers may be relatively straight or they may have crooked or bent portions to enhance entanglement with a bola line or lines or with each other. Two or more of such fingers may be used and may be regularly or irregularly spaced apart on a bola body. A bola with such bodies includes lines which are connected to the other bodies. In one particular embodiment of a bola body, according to the present invention, the body has an irregular shape with a bottom rectangular portion and a top pyramid portion forming a nose. A plurality of fingers is extended from the pyramidal top portion with one finger extended up and away from each of four corners of the top portion. Such a bola body tends to be initially oriented with its nose and fingers against an object being snared since the body is pulled nose first when a bola line is secured at the tip of the pyramidal portion of the bola body. With such a bola, an unwrapping bola body can slip around a target member so that two of the rod-shaped fingers catch a bola line and guide it into an area or crook between the fingers and a side of the top pyramidal portion of the bola body. Tension on the bola line maintains the line in the crook and tends to press the fingers against the unwrapped target member to stabilize the wrapping of the line about the target member. With such a bola, it is difficult for two or more lines unwrapping in different directions to move past one another without being forced together by line tension. Also, the fingers of such bola bodies may hook and hold each other. The fingers may also hook or entangle some object on or portion of the target member. A probable known target member has known dimensions and shapes so that

  9. Finger blood content, light transmission, and pulse oximetry errors.

    PubMed

    Craft, T M; Lawson, R A; Young, J D

    1992-01-01

    The changes in light emitting diode current necessary to maintain a constant level of light incident upon a photodetector were measured in 20 volunteers at the two wavelengths employed by pulse oximeters. Three states of finger blood content were assessed; exsanguinated, hyperaemic, and normal. The changes in light emitting diode current with changes in finger blood content were small and are not thought to represent a significant source of error in saturation as measured by pulse oximetry. PMID:1536406

  10. The Effect of Swan-neck and Boutonniere Deformities on the Outcome of Silicone Metacarpophalangeal Joint Arthroplasty in Rheumatoid Arthritis

    PubMed Central

    Chetta, Matthew; Burns, Patricia B.; Kim, H. Myra; Burke, Frank D.; Wilgis, E. F. Shaw; Fox, David A.; Chung, Kevin C.

    2014-01-01

    Purpose Rheumatoid arthritis patients with swan-neck deformities (SND) are postulated to have greater metacarpophalangeal (MCP) joint arc of motion (AOM) because of their need to flex the MCP joint to make a fist. Whereas the boutonniere deformity (BD) places the fingers into the flexed position creating less demand on the MCP joint for grip. This study analyzes the effect of these deformities on MCP joint AOM and hand function. Methods We measured the MCP joint AOM in 73 surgical patients. These data were allocated into groups by finger and hand deformity. We used linear regression models to analyze the effect of the finger deformity on the MCP joint AOM. Functional outcomes were measured by the Michigan Hand Outcomes Questionnaire (MHQ) and the Jebson-Taylor test (JTT). Results Nineteen fingers were categorized with BD, 95 fingers with SND, and 178 fingers with no deformity. The non-deformity group had the least AOM at baseline (16°) compared to the BD (26°) and SND (26°) groups. The mean AOM in the non-deformity group compared to the BD group at baseline was statistically significant but all groups had similar MCP joint AOM at long term follow-up. Mean MHQ and JTT scores were not significantly different amongst groups with the exception of JTT scores at baseline between BD and non-deformity. Discussion Our results did not support the hypothesis that patients with SND have better AOM compared to patients with BD. Patients with BD have worse function at baseline but there was no difference in function amongst groups at long-term follow-up. PMID:23985634

  11. Detecting overblown flute fingerings from the residual noise spectrum.

    PubMed

    Verfaille, Vincent; Depalle, Philippe; Wanderley, Marcelo M

    2010-01-01

    Producing a tone by increasing the blowing pressure to excite a higher frequency impedance minimum, or overblowing, is widely used in standard flute technique. In this paper, the effect of overblowing a fingering is explored with spectral analysis, and a fingering detector is designed based on acoustical knowledge and pattern classification techniques. The detector performs signal analysis of the strong broadband signal, that is, spectrally shaped by the pipe impedance, and measures the spectral energy during the attack around multiples of the fundamental frequency sub-multiples over the first octave and a half. It is trained and evaluated on sounds recorded with four expert performers. They played six series of tones from overblown and regular fingerings, with frequencies that are octave- and non-octave-related to the playing frequency. The best of the four proposed sound descriptors allows for a detection error below 1.3% for notes with two and three fingerings (C(5), D(5), C(6), and Cmusical sharp(6)) and below 14% for four (E(6)) or five fingerings (G(6)). The error is shown to dramatically increase when two fingerings' impedance become too similar (E(6) and A(4) and G(6) and C(5)). PMID:20058998

  12. Biomechanical Analysis of Force Distribution in Human Finger Extensor Mechanisms

    PubMed Central

    Hu, Dan; Ren, Lei; Howard, David; Zong, Changfu

    2014-01-01

    The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx's dorsum. A novel analytical approach based on the “Principle of Minimum Total Potential Energy” is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo. PMID:25126576

  13. Fluidic Channels Produced by Electro Hydrodynamic Viscous Fingering

    NASA Astrophysics Data System (ADS)

    Behler, Kristopher; Wetzel, Eric

    2010-03-01

    Viscous fingering is a term describing fingerlike extensions of liquid from a column of low viscosity liquid that has been injected into a more viscous liquid. The modification of viscous fingering, known as electro hydrodynamic viscous fingering (EHVF), utilizes large electrical potentials of 10-60 kV. The fingers see a reduction in size and increase in branching behavior due to the potential applied to the system. The resulting finely structured patterns are analogous to biological systems such as blood vessels and the lymphatic system. In this study silicone oils and water were studied in thin channel Hele-Shaw cells. The interfacial tension was optimized by altering the surfactant concentration in the silicone oils. EHVF of liquid filled packed beds consisting of beads and silicone oils showed retardation of the relaxation of the fingers after the voltage was turned off. Decreased relaxation provides a means to solidify patterns into a curable material, such as polydimethylsiloxane (PDMS). After the water is evacuated from the fingers, the cured materials then possess hollow channels that can be refilled and emptied, thus creating an artificial circulatory system.

  14. Integrating optical finger motion tracking with surface touch events.

    PubMed

    MacRitchie, Jennifer; McPherson, Andrew P

    2015-01-01

    This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction. PMID:26082732

  15. Integrating optical finger motion tracking with surface touch events

    PubMed Central

    MacRitchie, Jennifer; McPherson, Andrew P.

    2015-01-01

    This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction. PMID:26082732

  16. Biomechanical analysis of force distribution in human finger extensor mechanisms.

    PubMed

    Hu, Dan; Ren, Lei; Howard, David; Zong, Changfu

    2014-01-01

    The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx's dorsum. A novel analytical approach based on the "Principle of Minimum Total Potential Energy" is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo. PMID:25126576

  17. Viscous Fingering Induced Flow Instability in Multidimensional Liquid Chromatography

    SciTech Connect

    Mayfield, Kirsty; Shalliker, R. Andrew; Catchpoole, Heather J.; Sweeney, Alan P.; Wong, Victor; Guiochon, Georges A

    2005-07-01

    Viscous fingering is a flow instability phenomenon that results in the destabilisation of the interface between two fluids of differing viscosities. The destabilised interface results in a complex mixing of the two fluids in a pattern that resembles fingers. The conditions that enhance this type of flow instability can be found in coupled chromatographic separation systems, even when the solvents used in each of the separation stages have seemingly similar chemical and physical properties (other than viscosity). For example, the viscosities of acetonitrile and methanol are sufficiently different that instability at the interface between these two solvents can be established and viscous fingering results. In coupled chromatographic systems, the volume of solvent transported from one separation dimension to the second often exceeds the injection volume by two or more orders of magnitude. As a consequence, viscous fingering may occur, when otherwise following the injection of normal analytical size injection plugs viscous fingering would not occur. The findings in this study illustrate the onset of viscous fingering in emulated coupled chromatographic systems and show the importance of correct solvent selection for optimum separation performance.

  18. Rapid functional plasticity of the somatosensory cortex after finger amputation.

    PubMed

    Weiss, T; Miltner, W H; Huonker, R; Friedel, R; Schmidt, I; Taub, E

    2000-09-01

    Recent research indicates that areas of the primary somatosensory (SI) and primary motor cortex show massive cortical reorganization after amputation of the upper arm, forearm or fingers. Most of these studies were carried out months or several years after amputation. In the present study, we describe cortical reorganization of areas in the SI of a patient who underwent amputation of the traumatized middle and ring fingers of his right hand 10 days before cortical magnetic source imaging data were obtained. Somatosensory-evoked magnetic fields (SEF) to mechanical stimuli to the finger tips were recorded and single moving dipoles were calculated using a realistic volume conductor model. Results reveal that the dipoles representing the second and fifth fingers of the affected hand were closer together than the comparable dipoles of the unaffected hand. Our findings demonstrate that neural cell assemblies in SI which formerly represented the right middle and ring fingers of this amputee became reorganized and invaded by neighbouring cell assemblies of the index and little finger of the same hand. These results indicate that functional plasticity occurs within a period of 10 days after amputation. PMID:11037286

  19. Photoelectric angle converter

    NASA Astrophysics Data System (ADS)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  20. Comparison of the Thickness of Pulley and Flexor Tendon Between in Neutral and in Flexed Positions of Trigger Finger

    PubMed Central

    Sato, Junko; Ishii, Yoshinori; Noguchi, Hideo

    2016-01-01

    Objective: This study aims to compare the morphology of the A1 pulley and flexor tendons in idiopathic trigger finger of digits other than the thumb between in neutral position and in the position with the interphalangeal joints full flexed and with the metacarpophalangeal (MP) joint 0° extended (hook grip position). Method: A total of 48 affected digits and 48 contralateral normal digits from 48 patients who initially diagnosed with idiopathic trigger finger were studied sonographically. Sonographic analysis was focused on the A1 pulley and flexor tendons at the level of the MP joint in the transverse plane. We measured the anterior-posterior thickness of A1 pulley and the sum of the flexor digitorum superficialis and profundus tendons, and also measured the maximum radialulnar width of the flexor tendon in neutral and hook grip positions, respectively. Each measurement was compared between in neutral and in hook grip positions, and also between the affected and contralateral normal digits in each position. Results: In all the digits, the anterior-posterior thickness of flexor tendons significantly increased in hook grip position as compared with in neutral position, whereas radial-ulnar width significantly decreased. Both the A1 pulley and flexor tendons were thicker in the affected digits as compared with contralateral normal digits. Conclusion: The thickness of flexor tendons was significantly increased anteroposteriorly in hook grip position as compared with in neutral position. In trigger finger, A1 pulley and flexor tendon were thickened, and mismatch between the volume of the flexor tendon sheath and the tendons, especially in anterior-posterior direction, might be a cause of repetitive triggering. PMID:27099639

  1. Passive Ball Capture Joint

    NASA Technical Reports Server (NTRS)

    Cloyd, Richard A. (Inventor); Bryan, Thomas C. (Inventor)

    2003-01-01

    A passive ball capture joint has a sleeve with a plurality of bores distributed about a circumference thereof and formed therethrough at an acute angle relative to the sleeve's longitudinal axis. A spring-loaded retainer is slidingly fitted in each bore and is biased such that, if allowed, will extend at least partially into the sleeve to retain a ball therein. A ring, rotatably mounted about the bores, has an interior wall defining a plurality of shaped races that bear against the spring-loaded retainers. A mechanized rotational force producer is coupled to the ring. The ring can be rotated from a first position (that presses the retainers into the sleeve to lock the ball in place) to a second position (that allows the retainers to springback out of the sleeve to release the ball).

  2. Extra-articular fractures of the digital metacarpals and phalanges of the long fingers.

    PubMed

    Le Nen, D

    2014-02-01

    Metacarpal and phalangeal fractures of the long fingers are the result of trauma occurring under extremely varied circumstances. As a consequence, the clinical presentation varies greatly, with every bone and joint potentially being involved. Each step of their treatment is crucial, although the benign appearance of these injuries can lead to steps being missed: diagnostic phase with clinical examination and radiographs; therapeutic phase where the most suitable treatment is chosen, which combines mobilization of the digital chains as soon as possible and in every patient; follow-up phase with regular monitoring to detect any complications, especially secondary displacement, and verify that good progress is being made during rehabilitation. The goal of any fracture treatment is to preserve or restore the anatomy, with the emphasis here being on the stability and mobility of the digital chains. The potential progression towards serious functional sequelae (pain, instability or stiffness in hand) and the resulting significant socio-economic repercussions must be at the forefront of a surgeon's mind early on during the initial care of any finger or hand trauma. PMID:24486016

  3. Grip-force modulation in multi-finger prehension during wrist flexion and extension

    PubMed Central

    Ambike, Satyajit S.; Paclet, Florent; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2013-01-01

    Extrinsic digit muscles contribute to both fingertip forces and wrist movements (FDP and FPL – flexion, EDC - extension). Hence it is expected that finger forces depend on the wrist movement and position. We investigated the relation between grip force and wrist kinematics to examine whether and how the force: (1) scales with wrist flexion-extension (FE) angle; (2) can be predicted from accelerations induced during FE movement. In one experiment subjects naturally held an instrumented handle using a prismatic grasp and performed very slow FE movements. In another experiment, the same movement was performed cyclically at three prescribed frequencies. In quasistatic conditions, the grip force remained constant over the majority of the wrist range of motion. During the cyclic movements, the grip force changed. The changes were described with a linear regression model that represents the thumb and virtual finger (VF = four fingers combined) normal forces as the sum of the effects of the object’s tangential and radial accelerations and an object-weight-dependent constant term. The model explained 99% of the variability in the data. The independence of the grip force from wrist position agrees with the theory that that the thumb and VF forces are controlled with two neural variables that encode referent coordinates for each digit while accounting for changes in the position dependence of muscle forces, rather than a single neural variable like referent aperture. The results of the cyclical movement study extend the principle of superposition (some complex actions can be decomposed into independently controlled elemental actions) for a motor task involving simultaneous grip force exertion and wrist motion with significant length changes of the grip-force producing muscles. PMID:23625077

  4. Reading Angles in Maps

    PubMed Central

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2013-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15–53:30 months) were presented with fragments of geometric maps, in which angle sections appeared without any relevant length or distance information. Children were able to read these map fragments and compare 2D to 3D angles. However, this ability appeared both variable and fragile among the youngest children of the sample. These findings suggest that 4-year-old children begin to form an abstract concept of angle that applies both to 2D and 3D displays and that serves to interpret novel spatial symbols. PMID:23647223

  5. Angles, Time, and Proportion

    ERIC Educational Resources Information Center

    Pagni, David L.

    2005-01-01

    This article describes an investigation making connections between the time on an analog clock and the angle between the minute hand and the hour hand. It was posed by a middle school mathematics teacher. (Contains 8 tables and 6 figures.)

  6. Reading angles in maps.

    PubMed

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections appeared without any relevant length or distance information. Children were able to read these map fragments and compare two-dimensional to three-dimensional angles. However, this ability appeared both variable and fragile among the youngest children of the sample. These findings suggest that 4-year-old children begin to form an abstract concept of angle that applies both to two-dimensional and three-dimensional displays and that serves to interpret novel spatial symbols. PMID:23647223

  7. Type I locking of the metacarpophalangeal joint: A case report

    PubMed Central

    Al-Qattan, Mohammad M.; Rafique, Atif

    2016-01-01

    Introduction Type I locking of the metacarpophalangeal joint (MCPJ) is rare and is characterized by loss of extension at the MCPJ with full flexion of all joints of the digit. The condition is usually seen in the index and middle fingers when the normal osseous prominence or degenerative osteophytes of the radial condyle of the metacarpal head catches the accessory collateral ligaments of the MCPJ. Presentation of case We report on a case of Type I locking of the MCPJ affecting the index finger. The case was unusual because it might have been related to repeated stress while opening caps of specimen bottles in the laboratory. Furthermore, the impingement of the radial condyle of the metacarpal was to the sesamoid bone, and not to the collateral ligaments of the MCPJ. Finally, management was done by excision of the sesamoid bone rather than trimming of the prominence of the radial condyle of the metacarpals head. Discussion Locking of the metacarpophalangeal joint (MCPJ) should be viewed as two different entities: The “locked MCPJ with further flexion possible” (Type I locking) and the “locked MCPJ with further flexion not possible” (Type II locking). Once the type of MCPJ locking is diagnosed clinically, radiological testing (X-rays, CT scan, MRI) may be done to direct further management to the cause of locking. Conclusion We present an unusual case of Type I locking of the MCPJ affecting the index finger. PMID:27107503

  8. Experiments and kinematics analysis of a hand rehabilitation exoskeleton with circuitous joints.

    PubMed

    Zhang, Fuhai; Fu, Yili; Zhang, Qinchao; Wang, Shuguo

    2015-01-01

    Aiming at the hand rehabilitation of stroke patients, a wearable hand exoskeleton with circuitous joint is proposed. The circuitous joint adopts the symmetric pinion and rack mechanism (SPRM) with the parallel mechanism. The exoskeleton finger is a serial mechanism composed of three closed-chain SPRM joints in series. The kinematic equations of the open chain of the finger and the closed chains of the SPRM joints were built to analyze the kinematics of the hand rehabilitation exoskeleton. The experimental setup of the hand rehabilitation exoskeleton was built and the continuous passive motion (CPM) rehabilitation experiment and the test of human-robot interaction force measurement were conducted. Experiment results show that the mechanical design of the hand rehabilitation robot is reasonable and that the kinematic analysis is correct, thus the exoskeleton can be used for the hand rehabilitation of stroke patients. PMID:26406062

  9. [Fractures of the proximal interphalangeal joint: Diagnostic and operative therapy options].

    PubMed

    Unglaub, F; Langer, M F; Hahn, P; Müller, L P; Ahrens, C; Spies, C K

    2016-02-01

    Joint fractures of the fingers often entail operative interventions in contrast to extra-articular fractures. These types of fracture are inclined to dislocate in addition to the actual fracture. The proximal interphalangeal (PIP) joint in particular often shows comminuted fractures due to the long leverage of the finger and a relatively small diameter of the joint. The clinical examination, X-ray diagnostics and if necessary computed tomography allow the classification into stable and unstable fractures. Unstable fractures must be treated by surgical reduction and fixation. A multitude of operative techniques are available for these mostly complicated fractures. The foremost goal is a stable osteosynthesis of the fracture with repositioning of the dislocation, which enables early physiotherapy in order to prevent tendon adhesion and contracture. This article presents the different types of PIP joint fractures, their specific surgical treatment and postoperative treatment regimens. PMID:26826026

  10. 'Magic Angle Precession'

    SciTech Connect

    Binder, Bernd

    2008-01-21

    An advanced and exact geometric description of nonlinear precession dynamics modeling very accurately natural and artificial couplings showing Lorentz symmetry is derived. In the linear description it is usually ignored that the geometric phase of relativistic motion couples back to the orbital motion providing for a non-linear recursive precession dynamics. The high coupling strength in the nonlinear case is found to be a gravitomagnetic charge proportional to the precession angle and angular velocity generated by geometric phases, which are induced by high-speed relativistic rotations and are relevant to propulsion technologies but also to basic interactions. In the quantum range some magic precession angles indicating strong coupling in a phase-locked chaotic system are identified, emerging from a discrete time dynamical system known as the cosine map showing bifurcations at special precession angles relevant to heavy nuclei stability. The 'Magic Angle Precession' (MAP) dynamics can be simulated and visualized by cones rolling in or on each other, where the apex and precession angles are indexed by spin, charge or precession quantum numbers, and corresponding magic angles. The most extreme relativistic warping and twisting effect is given by the Dirac spinor half spin constellation with 'Hyperdiamond' MAP, which resembles quark confinement.

  11. Making fingers and words count in a cognitive robot

    PubMed Central

    De La Cruz, Vivian M.; Di Nuovo, Alessandro; Di Nuovo, Santo; Cangelosi, Angelo

    2013-01-01

    Evidence from developmental as well as neuroscientific studies suggest that finger counting activity plays an important role in the acquisition of numerical skills in children. It has been claimed that this skill helps in building motor-based representations of number that continue to influence number processing well into adulthood, facilitating the emergence of number concepts from sensorimotor experience through a bottom-up process. The act of counting also involves the acquisition and use of a verbal number system of which number words are the basic building blocks. Using a Cognitive Developmental Robotics paradigm we present results of a modeling experiment on whether finger counting and the association of number words (or tags) to fingers, could serve to bootstrap the representation of number in a cognitive robot, enabling it to perform basic numerical operations such as addition. The cognitive architecture of the robot is based on artificial neural networks, which enable the robot to learn both sensorimotor skills (finger counting) and linguistic skills (using number words). The results obtained in our experiments show that learning the number words in sequence along with finger configurations helps the fast building of the initial representation of number in the robot. Number knowledge, is instead, not as efficiently developed when number words are learned out of sequence without finger counting. Furthermore, the internal representations of the finger configurations themselves, developed by the robot as a result of the experiments, sustain the execution of basic arithmetic operations, something consistent with evidence coming from developmental research with children. The model and experiments demonstrate the importance of sensorimotor skill learning in robots for the acquisition of abstract knowledge such as numbers. PMID:24550795

  12. The effect of chalk on the finger-hold friction coefficient in rock climbing.

    PubMed

    Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

    2012-11-01

    The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing. PMID:23259237

  13. The Use of an MEG/fMRI-Compatible Finger Motion Sensor in Detecting Different Finger Actions

    PubMed Central

    Yong, Xinyi; Li, Yasong; Menon, Carlo

    2016-01-01

    This paper explores the use of a novel device in detecting different finger actions among healthy individuals and individuals with stroke. The device is magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) compatible. It was prototyped to have four air-filled chambers that are made of silicone elastomer, which contains low magnetizing materials. When an individual compresses the device with his/her fingers, each chamber experiences a change in pressure, which is detected by a pressure sensor. In a previous recent work, our device was shown to be MEG/fMRI compatible. In this study, our research effort focuses on using the device to detect different finger actions (e.g., grasping and pinching) in non-shielded rooms. This is achieved by applying a support vector machine to the sensor data collected from the device when participants are resting and executing the different finger actions. The total number of possible finger actions that can be executed using the device is 31. The healthy participants could perform all the 31 different finger actions and the average classification accuracy achieved is 95.53 ± 2.63%. The stroke participants could perform all the 31 different finger actions with their healthy hand and the average classification accuracy achieved is 83.13 ± 6.69%. Unfortunately, the functions of their affected hands are compromised due to stroke. Thus, the number of finger actions they could perform ranges from 2 to 24, depending on the level of impairments. The average classification accuracy for the affected hand is 83.99 ± 16.38%. The ability to identify different finger actions using the device can provide a mean to researchers to label the data automatically in MEG/fMRI studies. In addition, the sensor data acquired from the device provide sensorimotor-­related information, such as speed and force, when the device is compressed. Thus, brain activations can be correlated with this information during different

  14. Kinetostatics analysis of a novel 6-DOF parallel manipulator with three planar limbs and equipped with three fingers

    NASA Astrophysics Data System (ADS)

    Lu, Yi; Li, Xuepeng

    2014-09-01

    It is significant to develop a robot hand with high rigidity by a 6-DOF parallel manipulator(PM). However, the existing 6-DOF PMs include spherical joint which has less capability of pulling force bearing, less rotation range and lower precision under alternately heavy loads. A novel 6-DOF PM with three planar limbs and equipped with three fingers is proposed and its kinematics and statics are analyzed systematically. A 3-dimension simulation mechanism of the proposed manipulator is constructed and its structure characteristics is analyzed. The kinematics formulae for solving the displacement, velocity, acceleration of the platform, the active legs and the fingers are established. The statics formulae are derived for solving the active forces of PM and the finger mechanisms. An analytic example is given for solving the kinematics and statics of proposed manipulator and the analytic solved results are verified by the simulation mechanism. It is proved from the error analysis of analytic solutions and simulation solutions that the derived analytic formulae are correct and provide the theoretical and technical foundations for its manufacturing, control and application.

  15. Kinetostatics analysis of a novel 6-DOF parallel manipulator with three planar limbs and equipped with three fingers

    NASA Astrophysics Data System (ADS)

    Lu, Yi; Li, Xuepeng

    2014-08-01

    It is significant to develop a robot hand with high rigidity by a 6-DOF parallel manipulator(PM). However, the existing 6-DOF PMs include spherical joint which has less capability of pulling force bearing, less rotation range and lower precision under alternately heavy loads. A novel 6-DOF PM with three planar limbs and equipped with three fingers is proposed and its kinematics and statics are analyzed systematically. A 3-dimension simulation mechanism of the proposed manipulator is constructed and its structure characteristics is analyzed. The kinematics formulae for solving the displacement, velocity, acceleration of the platform, the active legs and the fingers are established. The statics formulae are derived for solving the active forces of PM and the finger mechanisms. An analytic example is given for solving the kinematics and statics of proposed manipulator and the analytic solved results are verified by the simulation mechanism. It is proved from the error analysis of analytic solutions and simulation solutions that the derived analytic formulae are correct and provide the theoretical and technical foundations for its manufacturing, control and application.

  16. Fusion of the First Metatarsophalangeal Joint: Precontoured or Straight Plate?

    PubMed

    Marsland, Daniel; Konan, Sujith; Eleftheriou, Kyriacos; Calder, James; Elliot, Robin R

    2016-01-01

    Precontoured, low-profile plates with fixed dorsiflexion angles are becoming increasingly popular for first metatarsophalangeal joint fusion. We have concerns that the routine use of a precontoured plate can lead to excessive clinical dorsiflexion. The aim of our study was to investigate the relationship between the first metatarsophalangeal joint dorsiflexion intramedullary angle and the angle formed at the dorsal cortices where the plate is applied. We hypothesized that the dorsal cortical angle was significantly less dorsiflexed than the intramedullary angle. We measured both angles on lateral weightbearing radiographs of 40 consecutive individuals presenting with forefoot symptoms. The results demonstrated that the mean dorsal cortical angle was significantly smaller (mean 0.2° plantarflexion) compared with the intramedullary angle (mean 10.6° dorsiflexion; p < .001). The interobserver and intraobserver reliability of both the intramedullary and the dorsal cortical measurements was very good. In conclusion, the dorsal cortical angle is, on average, 10.8° smaller than the intramedullary angle, with a mean angle of almost 0°. This finding should be considered when selecting plates for first metatarsophalangeal joint fusion. PMID:26968232

  17. Extrinsic Finger and Thumb Muscles Command a Virtual Hand to Allow Individual Finger and Grasp Control

    PubMed Central

    Hargrove, Levi J.; Weir, Richard F. ff.; Kuiken, Todd A.

    2015-01-01

    Fine-wire intramuscular electrodes were used to obtain EMG signals from six extrinsic hand muscles associated with the thumb, index, and middle fingers. Subjects’ EMG activity was used to control a virtual three-DOF hand as they conformed the hand to a sequence of hand postures testing two controllers: direct EMG control and pattern recognition control. Subjects tested two conditions using each controller: starting the hand from a pre-defined neutral posture before each new posture and starting the hand from the previous posture in the sequence. Subjects demonstrated their ability to simultaneously, yet individually, move all three DOFs during the direct EMG control trials, however results showed subjects did not often utilize this feature. Performance metrics such as failure rate and completion time showed no significant difference between the two controllers. PMID:25099395

  18. Magic Ring: A Finger-Worn Device for Multiple Appliances Control Using Static Finger Gestures

    PubMed Central

    Jing, Lei; Zhou, Yinghui; Cheng, Zixue; Huang, Tongjun

    2012-01-01

    An ultimate goal for Ubiquitous Computing is to enable people to interact with the surrounding electrical devices using their habitual body gestures as they communicate with each other. The feasibility of such an idea is demonstrated through a wearable gestural device named Magic Ring (MR), which is an original compact wireless sensing mote in a ring shape that can recognize various finger gestures. A scenario of wireless multiple appliances control is selected as a case study to evaluate the usability of such a gestural interface. Experiments comparing the MR and a Remote Controller (RC) were performed to evaluate the usability. From the results, only with 10 minutes practice, the proposed paradigm of gestural-based control can achieve a performance of completing about six tasks per minute, which is in the same level of the RC-based method. PMID:22778612

  19. A study of white finger in the gas industry.

    PubMed Central

    Walker, D D; Jones, B; Ogston, S; Tasker, E G; Robinson, A J

    1985-01-01

    Men engaged in breaking or reinstating road surfaces are exposed to vibration from mechanical tools. In view of the lack of epidemiological information on vibration white finger in such a population, a survey was carried out to identify the prevalence of symptoms of white finger in a sample of men using these tools in the gas industry and to compare the prevalence with that found in a control group not occupationally exposed to vibration. Altogether 905 men (97%) in the gas industry and 552 men (92%) in the control group were interviewed, using a questionnaire from which the presence or absence of white finger symptoms from all causes was noted. The prevalence of white finger was 9.6% in the group exposed to vibration at work compared with 9.5% in the control group. The prevalence in the former group when adjusted for age differences between the survey and control populations was 12.2%, but this difference did not reach statistical significance. In case the approach of comparing prevalences of white finger from all causes might have obscured any contributory effect of vibration, the prevalence of white finger was examined in relation to the number of years vibrating tools had been used, this being the only measure of exposure to vibration available. No direct association was found between the prevalence of symptoms and number of years vibrating tools had been used. In view of this and the absence of a significant excess of white finger symptoms in the group using vibratory tools, the authors conclude that vibration white finger is not a special problem in the gas industry. Nevertheless, experimental tests carried out on the different types of roadbreakers used in the industry and on different road surfaces indicate that the vibration levels exceed the standards advocated in the draft international standard DIS 5349 (1979) at the lower end of the frequency spectrum. That no particular problem has been found may be due to the relatively short exposures to vibration

  20. High-Speed, High-Temperature Finger Seal Test Evaluated

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2003-01-01

    A finger seal, designed and fabricated by Honeywell Engines, Systems and Services, was tested at the NASA Glenn Research Center at surface speeds up to 1200 ft/s, air temperatures up to 1200 F, and pressures across the seal of 75 psid. These are the first test results obtained with NASA s new High-Temperature, High-Speed Turbine Seal Test Rig (see the photograph). The finger seal is an innovative design recently patented by AlliedSignal Engines, which has demonstrated considerably lower leakage than commonly used labyrinth seals and is considerably cheaper than brush seals. The cost to produce finger seals is estimated to be about half of the cost to produce brush seals. Replacing labyrinth seals with fingers seals at locations that have high-pressure drops in gas turbine engines, typically main engine and thrust seals, can reduce air leakage at each location by 50 percent or more. This directly results in a 0.7- to 1.4-percent reduction in specific fuel consumption and a 0.35- to 0.7-percent reduction in direct operating costs . Because the finger seal is a contacting seal, this testing was conducted to address concerns about its heat generation and life capability at the higher speeds and temperatures required for advanced engines. The test results showed that the seal leakage and wear performance are acceptable for advanced engines.

  1. Fluid-driven fingering instability of a confined elastic meniscus

    NASA Astrophysics Data System (ADS)

    Biggins, John S.; Wei, Z.; Mahadevan, L.

    2015-05-01

    When a fluid is pumped into a cavity in a confined elastic layer, at a critical pressure, destabilizing fingers of fluid invade the elastic solid along its meniscus (Saintyves B. et al., Phys. Rev. Lett., 111 (2013) 047801). These fingers occur without fracture or loss of adhesion and are reversible, disappearing when the pressure is decreased. We develop an asymptotic theory of pressurized highly elastic layers trapped between rigid bodies in both rectilinear and circular geometries, with predictions for the critical fluid pressure for fingering, and the finger wavelength. Our results are in good agreement with recent experimental observations of this elastic interfacial instability in a radial geometry. Our theory also shows that, perhaps surprisingly, this lateral-pressure-driven instability is analogous to a transverse-displacement-driven instability of the elastic layer. We verify these predictions by using non-linear finite-element simulations on the two systems which show that in both cases the fingering transition is first order (sudden) and hence has a region of bistability.

  2. Traumatic Finger Injuries: What the Orthopedic Surgeon Wants to Know.

    PubMed

    Wieschhoff, Ged G; Sheehan, Scott E; Wortman, Jeremy R; Dyer, George S M; Sodickson, Aaron D; Patel, Ketan I; Khurana, Bharti

    2016-01-01

    Traumatic finger injuries account for a substantial number of emergency visits every year. Imaging plays an important role in diagnosis and in directing management of these injuries. Although many injuries can be managed conservatively, some require more invasive interventions to prevent complications and loss of function. Accurate diagnosis of finger injuries can often be difficult, given the complicated soft-tissue anatomy of the hand and the diverse spectrum of injuries that can occur. To best serve the patient and the treating physician, radiologists must have a working knowledge of finger anatomy, the wide array of injury patterns that can occur, the characteristic imaging findings of different finger injuries, and the most appropriate treatment options for each type of injury. This article details the intricate anatomy of the hand as it relates to common finger injuries, illustrates the imaging findings of a range of injuries, presents optimal imaging modalities and imaging parameters for the diagnosis of different injury types, and addresses which findings have important management implications for the patient and the orthopedic surgeon. With this fund of knowledge, radiologists will be able to recommend the most appropriate imaging studies, make accurate diagnoses, convey clinically relevant imaging findings to the referring physician, and suggest appropriate follow-up examinations. In this way, the radiologist will help improve patient care and outcomes. Online supplemental material is available for this article. (©)RSNA, 2016. PMID:27399238

  3. RNA binding by the Wilms tumor suppressor zinc finger proteins.

    PubMed Central

    Caricasole, A; Duarte, A; Larsson, S H; Hastie, N D; Little, M; Holmes, G; Todorov, I; Ward, A

    1996-01-01

    The Wilms tumor suppressor gene WT1 is implicated in the ontogeny of genito-urinary abnormalities, including Denys-Drash syndrome and Wilms tumor of the kidney. WT1 encodes Kruppel-type zinc finger proteins that can regulate the expression of several growth-related genes, apparently by binding to specific DNA sites located within 5' untranslated leader regions as well as 5' promoter sequences. Both WT1 and a closely related early growth response factor, EGR1, can bind the same DNA sequences from the mouse gene encoding insulin-like growth factor 2 (Igf-2). We report that WT1, but not EGR1, can bind specific Igf-2 exonic RNA sequences, and that the zinc fingers are required for this interaction. WT1 zinc finger 1, which is not represented in EGR1, plays a more significant role in RNA binding than zinc finger 4, which does have a counterpart in EGR1. Furthermore, the normal subnuclear localization of WT1 proteins is shown to be RNase, but not DNase, sensitive. Therefore, WT1 might, like the Kruppel-type zinc finger protein TFIIIA, regulate gene expression by both transcriptional and posttranscriptional mechanisms. Images Fig. 1 Fig. 2 Fig. 3 PMID:8755514

  4. Finger Vein Recognition Based on Personalized Weight Maps

    PubMed Central

    Yang, Gongping; Xiao, Rongyang; Yin, Yilong; Yang, Lu

    2013-01-01

    Finger vein recognition is a promising biometric recognition technology, which verifies identities via the vein patterns in the fingers. Binary pattern based methods were thoroughly studied in order to cope with the difficulties of extracting the blood vessel network. However, current binary pattern based finger vein matching methods treat every bit of feature codes derived from different image of various individuals as equally important and assign the same weight value to them. In this paper, we propose a finger vein recognition method based on personalized weight maps (PWMs). The different bits have different weight values according to their stabilities in a certain number of training samples from an individual. Firstly we present the concept of PWM, and then propose the finger vein recognition framework, which mainly consists of preprocessing, feature extraction, and matching. Finally, we design extensive experiments to evaluate the effectiveness of our proposal. Experimental results show that PWM achieves not only better performance, but also high robustness and reliability. In addition, PWM can be used as a general framework for binary pattern based recognition. PMID:24025556

  5. The biometric recognition on contactless multi-spectrum finger images

    NASA Astrophysics Data System (ADS)

    Kang, Wenxiong; Chen, Xiaopeng; Wu, Qiuxia

    2015-01-01

    This paper presents a novel multimodal biometric system based on contactless multi-spectrum finger images, which aims to deal with the limitations of unimodal biometrics. The chief merits of the system are the richness of the permissible texture and the ease of data access. We constructed a multi-spectrum instrument to simultaneously acquire three different types of biometrics from a finger: contactless fingerprint, finger vein, and knuckleprint. On the basis of the samples with these characteristics, a moderate database was built for the evaluation of our system. Considering the real-time requirements and the respective characteristics of the three biometrics, the block local binary patterns algorithm was used to extract features and match for the fingerprints and finger veins, while the Oriented FAST and Rotated BRIEF algorithm was applied for knuckleprints. Finally, score-level fusion was performed on the matching results from the aforementioned three types of biometrics. The experiments showed that our proposed multimodal biometric recognition system achieves an equal error rate of 0.109%, which is 88.9%, 94.6%, and 89.7% lower than the individual fingerprint, knuckleprint, and finger vein recognitions, respectively. Nevertheless, our proposed system also satisfies the real-time requirements of the applications.

  6. Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic Signals

    PubMed Central

    Wang, Z.; Ji, Q.; Miller, K. J.; Schalk, Gerwin

    2011-01-01

    Brain–computer interfaces (BCIs) use brain signals to convey a user’s intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG) recordings from the surface of the brain in humans can give information about kinematic parameters (e.g., hand velocity or finger flexion). The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS). Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation. PMID:22144944

  7. Angle at the Medial Border: The Spinovertebra Angle and Its Significance

    PubMed Central

    Oladipo, G. S.; Aigbogun, E. O.; Akani, G. L.

    2015-01-01

    Background. The evolution from quadrupedalism to bipedalism has adjusted the balance of the upper limb to extensive movement at the shoulder. The scapular angles provide the point of attachment and control to various muscles and have been associated with the different movements of the shoulder girdle and joint. This has made the morphometric and anthropometric study of scapula a subject of extensive investigation. Aim. In the present study, the angle at the medial border was measured in the South-Southern Nigerian population and an anatomical name was ascribed to the angle. Method. The study was conducted on 173 scapulae (75 right and 98 left) obtained from various Anatomy Department of South-Sothern Nigerian Universities. The angle at medial border was obtained by pinning the edge of the superior and inferior angles, the lined traced out, and the angle measured using a protractor. SPSS version 20 was used to analyse the data. t-test was used to determine mean angular difference in the sides. Result. The mean ± SD of the medial angle was observed to be 136.88 ± 7.70° (R = 138.13 ± 7.06° : L = 135.92 ± 8.05°). Statistical analysis using the Z-test for mean difference showed the medial angle was found to be higher in the right side of the scapula (mean difference of 2.214 ± 1.152°), but the observed difference was not statistically significant (P > 0.05). The above findings have adjusted the scapula from three to four angles (lateral, superior, inferior, and medial) formed from four borders (lateral, superior, inferior, and superomedial and inferomedial). The medial angle because of its anatomical location was named “spinovertebral” angle, owing to its position at the scapulae spine, and located in medial proximity to the vertebra column. Conclusion. The medial angle (now referred to as the spinovertebral angle) of the right side of the scapula is wider than the left. The representation of the spinovertebral angle is very important, as the

  8. Angle at the Medial Border: The Spinovertebra Angle and Its Significance.

    PubMed

    Oladipo, G S; Aigbogun, E O; Akani, G L

    2015-01-01

    Background. The evolution from quadrupedalism to bipedalism has adjusted the balance of the upper limb to extensive movement at the shoulder. The scapular angles provide the point of attachment and control to various muscles and have been associated with the different movements of the shoulder girdle and joint. This has made the morphometric and anthropometric study of scapula a subject of extensive investigation. Aim. In the present study, the angle at the medial border was measured in the South-Southern Nigerian population and an anatomical name was ascribed to the angle. Method. The study was conducted on 173 scapulae (75 right and 98 left) obtained from various Anatomy Department of South-Sothern Nigerian Universities. The angle at medial border was obtained by pinning the edge of the superior and inferior angles, the lined traced out, and the angle measured using a protractor. SPSS version 20 was used to analyse the data. t-test was used to determine mean angular difference in the sides. Result. The mean ± SD of the medial angle was observed to be 136.88 ± 7.70° (R = 138.13 ± 7.06° : L = 135.92 ± 8.05°). Statistical analysis using the Z-test for mean difference showed the medial angle was found to be higher in the right side of the scapula (mean difference of 2.214 ± 1.152°), but the observed difference was not statistically significant (P > 0.05). The above findings have adjusted the scapula from three to four angles (lateral, superior, inferior, and medial) formed from four borders (lateral, superior, inferior, and superomedial and inferomedial). The medial angle because of its anatomical location was named "spinovertebral" angle, owing to its position at the scapulae spine, and located in medial proximity to the vertebra column. Conclusion. The medial angle (now referred to as the spinovertebral angle) of the right side of the scapula is wider than the left. The representation of the spinovertebral angle is very important, as the directional

  9. Development of cylindrical-type finger force measuring system using force sensors and its characteristics evaluation

    NASA Astrophysics Data System (ADS)

    Kim, Hyeon-Min; Yoon, Joungwon; Shin, Hee-Suk; Kim, Gab-Soon

    2012-02-01

    Some patients cannot use their hands because of the paralysis of their fingers. Their fingers can recover with rehabilitative training, and the extent of rehabilitation can be judged by grasping a cylindrical-object with their fingers. At present, the cylindrical-object used in hospitals is only a plastic cylinder, which cannot measure grasping force of the fingers. Therefore, doctors must judge the extent of rehabilitation by watching patients' fingers as they grasp the plastic cylinder. In this paper, the development of two cylindrical-type finger force measuring systems with four force sensors for left hand and right hand were developed. The developed finger force measuring system can measure the grasping force of patients' each finger (forefinger, middle finger, ring finger and little finger), and the measured results could be used to judge the rehabilitation extent of a finger patient. The grasping force tests of men and women were performed using the developed cylindrical-type finger force measuring systems. The tests confirm that the average finger forces of right hand and left hand for men were about 194 N and 179 N, and for women, 108 N and 95 N.

  10. Index and ring finger ratio--a morphologic sex determinant in South-Indian children.

    PubMed

    Kanchan, Tanuj; Pradeep Kumar, G

    2010-12-01

    To investigate the sexual dimorphism of index and ring finger ratio in South Indian children. The index finger length (IFL) and the ring finger length (RFL) were measured in 350 subjects aged between 2 and 12 years using a steel measuring tape. The index and ring finger ratio was computed by dividing index finger length by ring finger length. The data obtained were analyzed statistically using SPSS, version 11.0. Mean RFL was greater than mean IFL in both males and females. The mean ring finger length was longer in males than females and mean index finger length longer in females than males. However, these sex differences observed for index and ring finger length were not significant in both hands. Statistically significant sex differences were observed from the derived index and ring finger ratio. The mean index and ring finger ratio was found to be higher in females than males. Significant correlation was found between age and index and ring finger lengths. Index and ring finger ratio however, did not show any significant correlation with age. This study suggests that among South-Indian children, the index and ring finger ratio of 0.97 and less is indicative of male, and a ratio of more than 0.97 is indicative of female sex. The ratio can be a useful sex indicator irrespective of the age of the individual. PMID:20369311

  11. MR microscopy of the human finger and correlation with histology--a proof-of-principle study.

    PubMed

    Langner, I; Krüger, P-C; Evert, K; Zach, A; Hadlich, S; Ekkernkamp, A; Eisenschenk, A; Hosten, N; Langner, S

    2013-09-01

    Magnetic resonance imaging (MRI) with small surface coils is a well established method for the diagnostic evaluation of finger masses. Until now, histological examination has been required to reliably assess tumor extent and infiltration of surrounding structures. Ultra-high-field MR microscopy (MRM) allows evaluation of anatomical structures and pathologies with submillimeter resolution. This study describes the diagnostic prospects and potential of MRM based on the ex-vivo examination of different finger pathologies. Ten human digits were examined by ex-vivo MRM at 7.1 Tesla (ClinScan, Bruker BioScan) using a T2-weighted turbo spin echo (TSE) sequence. Imaging parameters were: TE 48 ms; TR 8370 ms; slice thickness 700 µm; matrix size 1024 × 1024 pixels; FOV 37 × 37 mm; in-plane resolution 36 × 36 µm/voxel. Afterwards specimens were examined histologically. Histology and MRM were correlated. MRM allowed evaluation of the anatomy of the nail, the tendon insertions, the distal interphalangeal joint, and the neurovascular bundles. Finger abnormalities evaluated by MRM included osteomyelitis and metastatic disease. Subsequent histological examination confirmed MRM findings regarding origin, internal makeup, and extent of the structures visualized. This study demonstrates the potential of MRM for imaging small anatomical structures and pathologies of the human finger. Our ex-vivo findings correlate strongly with histology, suggesting that MRM may gain a central role in assessing anatomical structures and pathology in terms of morphology, extent, and infiltration of surrounding structures. Therefore, with increasing availability, MRM is expected to become an essential tool not only in experimental studies but also for daily routine. PMID:23553800

  12. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of completion of a PDP is required to be filed with the Food and Drug... constrained uncemented prosthesis shall have an approved PMA or a declared completed PDP in effect...

  13. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of completion of a PDP is required to be filed with the Food and Drug... constrained uncemented prosthesis shall have an approved PMA or a declared completed PDP in effect...

  14. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Classification. Class III. (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of... approved PMA or a declared completed PDP in effect before being placed in commercial distribution....

  15. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Classification. Class III. (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of... approved PMA or a declared completed PDP in effect before being placed in commercial distribution....

  16. Joint instability and osteoarthritis.

    PubMed

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

  17. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  18. Joint Instability and Osteoarthritis

    PubMed Central

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

  19. Targeted Mutagenesis in Zebrafish Using Customized Zinc Finger Nucleases

    PubMed Central

    Foley, Jonathan E.; Maeder, Morgan L.; Pearlberg, Joseph; Joung, J. Keith; Peterson, Randall T.; Yeh, Jing-Ruey J.

    2009-01-01

    Zebrafish mutants have traditionally been obtained using random mutagenesis or retroviral insertions, methods that cannot be targeted to a specific gene and require laborious gene mapping and sequencing. Recently, we and others have shown that customized zinc finger nucleases (ZFNs) can introduce targeted frame-shift mutations with high efficiency, thereby enabling directed creation of zebrafish gene mutations. Here we describe a detailed protocol for constructing ZFN expression vectors, for generating and introducing ZFN-encoding RNAs into zebrafish embryos, and for identifying ZFN-generated mutations in targeted genomic sites. All of our vectors and methods are compatible with previously described Zinc Finger Consortium reagents for constructing engineered zinc finger arrays. Using these methods, zebrafish founders carrying targeted mutations can be identified within four months. PMID:20010934

  20. Prognostic factors on survival rate of fingers replantation

    PubMed Central

    Lima, José Queiroz; Carli, Alberto De; Nakamoto, Hugo Alberto; Bersani, Gustavo; Crepaldi, Bruno Eiras; de Rezende, Marcelo Rosa

    2015-01-01

    Objective: To evaluate the factors that influence the survival rate of replantation and revascularization of the thumb and/or fingers. Methods: We included fifty cases treated in our department from May 2012 to October 2013 with total or partial finger amputations, which had blood perfusion deficit and underwent vascular anastomosis. The parameters evaluated were: age, gender, comorbidities, trauma, time and type of ischemia, mechanism, the injured area, number of anastomosed vessels and use of vein grafts. The results were statistically analyzed and type I error value was set at p <0.05 . Results: Fifty four percent of the 50 performed replantation survived. Of 15 revascularizations performed, the survival rate was 93.3%. The only factor that affected the survival of the amputated limb was the necessity of venous anastomosis. Conclusion: We could not establish contraindications or absolute indications for the replantation and revascularization of finger amputations in this study. Level of Evidence III, Retropective Study. PMID:26327788

  1. Arthropathy, ankylosing spondylitis, and clubbing of fingers in ulcerative colitis

    PubMed Central

    Jalan, K. N.; Prescott, R. J.; Walker, R. J.; Sircus, W.; McManus, J. P. A.; Card, W. I.

    1970-01-01

    In a retrospective study of 399 patients with ulcerative colitis, 27 patients had colitic arthritis, 17 had ankylosing spondylitis, and 20 had clubbing of the fingers. Colitic arthritis and ankylosing spondylitis were not related to severity, extent of involvement, or duration of colitis. A significant association between colitic arthropathy and other complications of ulcerative colitis, such as pseudopolyposis, perianal disease, eye lesions, skin eruptions, aphthous ulceration, and liver disease has been demonstrated. The outcome of the first referred attack of colitis in the presence of colitic arthritis and ankylosing spondylitis remained uninfluenced. Clubbing of fingers was related to severity, extent of involvement, and length of the history of colitis. A significant association between clubbing of the fingers and carcinoma of the colon, pseudopolyposis, toxic dilatation, and arthropathy has been shown. The frequency of surgical intervention in patients with clubbing was higher but the overall mortality was not significantly different from the patients without clubbing. PMID:5473606

  2. High-Speed, High-Temperature Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.; Kumar, Arun; Delgado, Irebert R.

    2002-01-01

    Finger seals have significantly lower leakage rates than conventional labyrinth seals used in gas turbine engines and are expected to decrease specific fuel consumption by over 1 percent and to decrease direct operating cost by over 0.5 percent. Their compliant design accommodates shaft growth and motion due to thermal and dynamic loads with minimal wear. The cost to fabricate these finger seals is estimated to be about half the cost to fabricate brush seals. A finger seal has been tested in NASA's High Temperature, High Speed Turbine Seal Test Rig at operating conditions up to 1200 F, 1200 ft/s, and 75 psid. Static, performance and endurance test results are presented. While seal leakage and wear performance are acceptable, further design improvements are needed to reduce the seal power loss.

  3. Regulation of cancer stem cells by RING finger ubiquitin ligases

    PubMed Central

    Sun, Xiao-Hong

    2014-01-01

    Like normal stem cells, cancer stem cells (CSCs) are capable of self-renewal, either by symmetric or asymmetric cell division. They have the exclusive ability to reproduce malignant tumors indefinitely, and to confer resistance in response to radiation or chemotherapy. The ubiquitin modification system plays various roles in physiology and pathology. The key component for the specificity of this system is ubiquitin ligases (E3s). Of these E3s, the majority are RING finger proteins. Many RING finger E3s, such as the Cullin1-Skp1-F-box protein (SCF) E3s, CBL, BRCA1, MDM2 and von Hippel-Lindau tumour suppressor (VHL), are crucial in the regulation of cell-cycle progression and cell differentiation. As a result, many RING finger E3s are implicated in the positive and negative regulation of CSC maintenance. This review summarizes current knowledge in this research field. PMID:27358852

  4. Finger Pricking and Pain: A Never Ending Story

    PubMed Central

    Heinemann, Lutz

    2008-01-01

    Without finger pricking, no self-measurement of blood glucose (SMBG) is possible. However, the number of scientific studies dealing with this topic, which is highly relevant for patients, is surprisingly small. This is in sharp contrast to the number of papers about blood glucose meters and SMBG in general. This article highlights a number of aspects that are relevant when it comes to finger pricking and pain. There is a clear improvement in the technology employed in the many different lancing devices that are on the market nowadays; however, no good head-to-head comparison study has been performed to date. The invention of novel devices for finger pricking will most likely bring more attention to this topic. PMID:19885279

  5. Finger sudorometry and assessment of the sudomotor drive.

    PubMed

    Satchell, P; Ware, S; Barron, J; Tuck, R

    1994-08-01

    Sudorometry of the finger was carried out using the ventilated capsule method, the aim being to use the level of relative humidity within the sudorometer as an indirect measure of the sudomotor drive. Subjects inserted a finger through a diaphragm of a finger-shaped, temperature-controlled chamber which also contained the humidity sensor. Manoeuvres known to alter the sudomotor drive produced changes in chamber humidity. The relative humidity within the sudorometer became constant after local anaesthesia of the digital nerves and after upper limb sympathectomy, suggesting that fluctuations in the sudorometer output were dependent upon an intact autonomic nervous system. In an environment in which temperature was controlled and arousal effects from the process of measurement were minimised, chamber humidity always increased during a Stroop test, providing a rapid means of indirectly assessing sudomotor drive mechanisms. PMID:7823624

  6. Effect of transcranial magnetic stimulation on force of finger pinch

    NASA Astrophysics Data System (ADS)

    Odagaki, Masato; Fukuda, Hiroshi; Hiwaki, Osamu

    2009-04-01

    Transcranial magnetic stimulation (TMS) is used to explore many aspects of brain function, and to treat neurological disorders. Cortical motor neuronal activation by TMS over the primary motor cortex (M1) produces efferent signals that pass through the corticospinal tracts. Motor-evoked potentials (MEPs) are observed in muscles innervated by the stimulated motor cortex. TMS can cause a silent period (SP) following MEP in voluntary electromyography (EMG). The present study examined the effects of TMS eliciting MEP and SP on the force of pinching using two fingers. Subjects pinched a wooden block with the thumb and index finger. TMS was applied to M1 during the pinch task. EMG of first dorsal interosseous muscles and pinch forces were measured. Force output increased after the TMS, and then oscillated. The results indicated that the motor control system to keep isotonic forces of the muscles participated in the finger pinch was disrupted by the TMS.

  7. Finger Vein Recognition Based on a Personalized Best Bit Map

    PubMed Central

    Yang, Gongping; Xi, Xiaoming; Yin, Yilong

    2012-01-01

    Finger vein patterns have recently been recognized as an effective biometric identifier. In this paper, we propose a finger vein recognition method based on a personalized best bit map (PBBM). Our method is rooted in a local binary pattern based method and then inclined to use the best bits only for matching. We first present the concept of PBBM and the generating algorithm. Then we propose the finger vein recognition framework, which consists of preprocessing, feature extraction, and matching. Finally, we design extensive experiments to evaluate the effectiveness of our proposal. Experimental results show that PBBM achieves not only better performance, but also high robustness and reliability. In addition, PBBM can be used as a general framework for binary pattern based recognition. PMID:22438735

  8. Interfacial instabilities and fingering formation in Hele-Shaw flow

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Jun

    1996-10-01

    The interfacial instability of Hele-Shaw flow has been a crucial issue for the understanding of the pattern formation of viscous fingers in a Hele-Shaw cell. By using a unified asymptotic approach, we derive two different types of instability mechanisms for slightly' time-dependent finger solutions; namely, (i) the global-trapped-wave (GTW) instability; and (ii) the zero-frequency (null-f) instability. On the basis of these instability mechanisms, the selection of viscous finger formation is clarified; the apparent contradiction between the previous linearstability analysis by Tanveer (1987, Phys. Fluid 30, 1589) and others and the numerical simulations by DeGregoria & Schwartz (1986, J. Fluid Mech. 164, 383)and the experimental evidence is reconciled.

  9. Custom-Made Finger Guard to Prevent Wire-Stick Injury to the Operator's Finger while Performing Intermaxillary Fixation

    PubMed Central

    Kumaresan, Ramesh; Ponnusami, Karthikeyan; Karthikeyan, Priyadarshini

    2014-01-01

    The treatment of maxillofacial fractures involves different methods from bandages and splinting to methods of open reduction and internal fixation and usually requires control of the dental occlusion with the help of intermaxillary fixation (IMF). Different wiring techniques have been used to aid in IMF including placement of custom-made arch bars, eyelet etc. However, these wiring techniques are with a constant danger of trauma to the surgeon's fingers by their sharp ends. Though there exist a variety of commercially available barrier products and customized techniques to prevent wire-stick injury, cost factor, touch sensitivity, and comfort aspect restrain their acquirement and exploit. This technical note describes the construction of a simple and economical finger guard made of soft thermoplastic material that provides an added protection to fingers from wire-stick type injuries, and its flexible nature permits a comfortable finger flexion movement and acceptable touch sensitivity. This is a simple, economical, reusable puncture, and cut-resistance figure guard by which we can avoid wire-stick type injury to the operator's fingers during wiring technique. PMID:25383158

  10. Computing with liquid crystal fingers: models of geometric and logical computation.

    PubMed

    Adamatzky, Andrew; Kitson, Stephen; Costello, Ben De Lacy; Matranga, Mario Ariosto; Younger, Daniel

    2011-12-01

    When a voltage is applied across a thin layer of cholesteric liquid crystal, fingers of cholesteric alignment can form and propagate in the layer. In computer simulation, based on experimental laboratory results, we demonstrate that these cholesteric fingers can solve selected problems of computational geometry, logic, and arithmetics. We show that branching fingers approximate a planar Voronoi diagram, and nonbranching fingers produce a convex subdivision of concave polygons. We also provide a detailed blueprint and simulation of a one-bit half-adder functioning on the principles of collision-based computing, where the implementation is via collision of liquid crystal fingers with obstacles and other fingers. PMID:22304104

  11. Continuous non-invasive finger blood pressure monitoring in children.

    PubMed

    Tanaka, H; Thulesius, O; Yamaguchi, H; Mino, M; Konishi, K

    1994-06-01

    We evaluated the performance of continuous non-invasive finger arterial pressure measurement using the volume-clamp technique (Finapres). This study was designed to compare finger arterial pressure with brachial blood pressure estimated by the auscultatory method in 217 children (90 boys and 127 girls) aged 4-16 years and in 38 adults (aged 18-45 years). Finger and brachial artery pressure readings were obtained consecutively from the ipsilateral side in the supine position. Finger arterial pressure waveforms were recorded in all children except 4 with small and thin fingers. There was good agreement for systolic pressure with only a slight underestimation of 1.9 mmHg and 5.1 mmHg lower for diastolic pressure. This difference most probably reflects inaccuracy of the auscultatory cuff method rather than an error in the Finapres. There was large inter-individual variability in Finapres recordings which might be due to differences in vasomotor tone, as demonstrated by systolic amplification in 5 patients with anorexia. However, Finapres showed a small within-subject variability (3.8 mmHg for systolic and 4.1 mmHg for diastolic pressure) determined in 5 patients during phenylephrine infusion, and as good reproducibility as the auscultatory method. These results suggest that finger arterial pressure measurement in children older than 6 years of age has similar accuracy as that in adults, and that this method is useful for clinical applications in children, especially for the non-invasive evaluation of autonomic control and cardiovascular reflexes involving transient and rapid blood pressure changes. PMID:7919764

  12. Motor equivalence during multi-finger accurate force production

    PubMed Central

    Mattos, Daniela; Schöner, Gregor; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2014-01-01

    We explored stability of multi-finger cyclical accurate force production action by analysis of responses to small perturbations applied to one of the fingers and inter-cycle analysis of variance. Healthy subjects performed two versions of the cyclical task, with and without an explicit target. The “inverse piano” apparatus was used to lift/lower a finger by 1 cm over 0.5 s; the subjects were always instructed to perform the task as accurate as they could at all times. Deviations in the spaces of finger forces and modes (hypothetical commands to individual fingers) were quantified in directions that did not change total force (motor equivalent) and in directions that changed the total force (non-motor equivalent). Motor equivalent deviations started immediately with the perturbation and increased progressively with time. After a sequence of lifting-lowering perturbations leading to the initial conditions, motor equivalent deviations were dominating. These phenomena were less pronounced for analysis performed with respect to the total moment of force with respect to an axis parallel to the forearm/hand. Analysis of inter-cycle variance showed consistently higher variance in a subspace that did not change the total force as compared to the variance that affected total force. We interpret the results as reflections of task-specific stability of the redundant multi-finger system. Large motor equivalent deviations suggest that reactions of the neuromotor system to a perturbation involve large changes of neural commands that do not affect salient performance variables, even during actions with the purpose to correct those salient variables. Consistency of the analyses of motor equivalence and variance analysis provides additional support for the idea of task-specific stability ensured at a neural level. PMID:25344311

  13. High-resolution three-dimensional structure of a single zinc finger from a human enhancer binding protein in solution.

    PubMed

    Omichinski, J G; Clore, G M; Appella, E; Sakaguchi, K; Gronenborn, A M

    1990-10-01

    The three-dimensional structure of a 30-residue synthetic peptide containing the carboxy-terminal "zinc finger" motif of a human enhancer binding protein has been determined by two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy and hybrid distance geometry-dynamical simulated annealing calculations. The structure determination is based on 487 approximate interproton distance and 63 torsion angle (phi, psi, and chi 1) restraints. A total of 40 simulated annealing structures were calculated, and the atomic rms distribution about the mean coordinate positions (excluding residues 29 and 30 which are ill-defined) is 0.4 A for the backbone atoms, 0.8 A for all atoms, and 0.41 A for all atoms excluding the lysine and arginine side chains, which are disordered. The solution structure of the zinc finger consists of two irregular antiparallel beta-strands connected by an atypical turn (residues 3-12) and a classical alpha-helix (residues 14-24). The zinc is tetrahedrally coordinated to the sulfur atoms of two cysteines (Cys-5 and Cys-8) and to the N epsilon 2 atoms of two histidines (His-21 and His-27). The two cysteine residues are located in the turn connecting the two beta-strands (residues 5-8); one of the histidine ligands (His-21) is in the alpha-helix, while the second histidine (His-27) is at the end of a looplike structure (formed by the end of the alpha-helix and a turn). The general architecture is qualitatively similar to two previously determined low-resolution Cys2-His2 zinc finger structures, although distinct differences can be observed in the beta-strands and turn and in the region around the two histidines coordinated to zinc. Comparison of the overall polypeptide fold of the enhancer binding protein zinc finger with known structures in the crystallographic data base reveals a striking similarity to one region (residues 23-44) of the X-ray structure of proteinase inhibitor domain III of Japanese quail ovomucoid [Papamokos, E., Weber, E., Bode

  14. In vivo analysis of trapeziometacarpal joint kinematics during pinch tasks.

    PubMed

    Kuo, Li-Chieh; Lin, Chien-Ju; Chen, Guan-Po; Jou, I-Ming; Wang, Chien-Kuo; Goryacheva, Irina G; Dosaev, Marat Z; Su, Fong-Chin

    2014-01-01

    This study investigated how the posture of the thumb while performing common pinch movements and the levels of pinch force applied by the thumb affect the arthrokinematics of the trapeziometacarpal joint in vivo. Fifteen subjects performed the pinch tasks at the distal phalange (DP), proximal interphalangeal (PIP) joint, and metacarpophalangeal (MP) joint of the index finger with 0%, 50%, and 80% of maximal pinch forces by a single-axis load cell. 3D images of the thumb were obtained using the computed tomography. The results show that the reference points moved from the central region to the dorsal-radial region when changing from pinching the DP to the MP joint without pinching force being applied. Pinching with 80% of the maximum pinching force resulted in reference points being the closest to the volar-ulnar direction. Significant differences were seen between 0% and 50% of maximum pinch force, as well as between 0% and 80%, when pinching the MP joint in the distal-proximal direction. The effects of posture of the thumb and applied pinch force on the arthrokinematics of the joint were investigated with a 3D model of the trapeziometacarpal joint. Pinching with more than 50% of maximum pinch force might subject this joint to extreme displacement. PMID:24683540

  15. In Vivo Analysis of Trapeziometacarpal Joint Kinematics during Pinch Tasks

    PubMed Central

    Chen, Guan-Po; Jou, I-Ming; Goryacheva, Irina G.; Dosaev, Marat Z.; Su, Fong-Chin

    2014-01-01

    This study investigated how the posture of the thumb while performing common pinch movements and the levels of pinch force applied by the thumb affect the arthrokinematics of the trapeziometacarpal joint in vivo. Fifteen subjects performed the pinch tasks at the distal phalange (DP), proximal interphalangeal (PIP) joint, and metacarpophalangeal (MP) joint of the index finger with 0%, 50%, and 80% of maximal pinch forces by a single-axis load cell. 3D images of the thumb were obtained using the computed tomography. The results show that the reference points moved from the central region to the dorsal-radial region when changing from pinching the DP to the MP joint without pinching force being applied. Pinching with 80% of the maximum pinching force resulted in reference points being the closest to the volar-ulnar direction. Significant differences were seen between 0% and 50% of maximum pinch force, as well as between 0% and 80%, when pinching the MP joint in the distal-proximal direction. The effects of posture of the thumb and applied pinch force on the arthrokinematics of the joint were investigated with a 3D model of the trapeziometacarpal joint. Pinching with more than 50% of maximum pinch force might subject this joint to extreme displacement. PMID:24683540

  16. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  17. The Rainbow Angle.

    ERIC Educational Resources Information Center

    Sims, B.

    1978-01-01

    Two articles in the "Scientific American" form the background of this note. The rainbow angle for the primary bow of a monochromatic Cartesian rainbow is calculated. Special projects for senior high school students could be patterned after this quantitative study. (MP)

  18. An Iterative Angle Trisection

    ERIC Educational Resources Information Center

    Muench, Donald L.

    2007-01-01

    The problem of angle trisection continues to fascinate people even though it has long been known that it can't be done with straightedge and compass alone. However, for practical purposes, a good iterative procedure can get you as close as you want. In this note, we present such a procedure. Using only straightedge and compass, our procedure…

  19. Yaw Angle Demonstration

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Large Angle Magnetic Suspension Test Fixture (LAMSTF) is a 5 degree-of -freedom repulsive force magnetic suspension system designed to study the control of objects over large magnetic gaps. A digital control algorithm uses 6 sets of laser-sheet sensors and 5 control coils to position a cylinder 3' above the plane of electromagnetics

  20. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…