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Sample records for rasmus grip jan-gunnar

  1. GRIPPING TOOL

    DOEpatents

    Sandrock, R.J.

    1961-12-12

    A self-actuated gripping tool is described for transferring fuel elements and the like into reactors and other inaccessible locations. The tool will grasp or release the load only when properly positioned for this purpose. In addition, the load cannot be released except when unsupported by the tool, so that jarring or contact will not bring about accidental release of the load. The gripping members or jaws of the device are cam-actuated by an axially slidable shaft which has two lockable positions. A spring urges the shaft into one position and a solenoid is provided to overcome the spring and move it into the other position. The weight of the tool operates a sleeve to lock the shaft in its existing position. Only when the cable supporting the tool is slack is the device capable of being actuated either to grasp or release its load. (AEC)

  2. Wire Test Grip Fixture

    NASA Technical Reports Server (NTRS)

    Burke, Christopher S.

    2011-01-01

    Wire-testing issues, such as the gripping strains imposed on the wire, play a critical role in obtaining clean data. In a standard test frame fitted with flat wedge grips, the gripping action alone creates stresses on the wire specimen that cause the wire to fail at the grip location. A new test frame, which is outfitted with a vacuum chamber, negated the use of any conventional commercially available wire test fixtures, as only 7 in. (17.8 cm) existed between the grip faces. An innovative grip fixture was designed to test thin gauge wire for a variety of applications in an existing Instron test frame outfitted with a vacuum chamber.

  3. NASA GRIP Mission

    NASA Video Gallery

    NASA is getting a GRIP on hurricanes in 2010. The Genesis and Rapid Intensification Processes (GRIP) experiment will help us better understand how tropical storms form and develop into major hurric...

  4. Grips for Lightweight Tensile Specimens

    NASA Technical Reports Server (NTRS)

    Witte, William G., Jr.; Gibson, Walter D.

    1987-01-01

    Set of grips developed for tensile testing of lightweight composite materials. Double-wedge design substantially increases gripping force and reduces slippage. Specimen held by grips made of hardened wedges. Assembly screwed into load cell in tensile-testing machine.

  5. Timelapse: GRIPS Assembly

    NASA Video Gallery

    The GRIPS team integrated and tested their balloon payload at NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, July 18-Aug. 28, 2015. After putting the finishing touches on the payl...

  6. NASA Hurricane Mission - GRIP

    NASA Video Gallery

    This is an overview of NASA's hurricane research campaign called Genesis and Rapid Intensification Processes (GRIP). The six-week mission was conducted in coordination with NOAA and the National Sc...

  7. Bi-stem gripping apparatus

    NASA Technical Reports Server (NTRS)

    Sanders, Fred G. (Inventor)

    1988-01-01

    This invention relates to devices which grip cylindrical structures and more particularly to a device which has three arcuate gripping members having frictional surfaces for gripping and compressing a bi-stem. The bi-stem gripping apparatus is constructed having a pair of side gripping members, and an intermediate gripping member disposed between them. Sheets of a gum stock silicone rubber with frictional gripping surfaces are bonded to the inner region of the gripping members and provide frictional engagement between the bi-stem and the apparatus. A latch secures the gripping apparatus to a bi-stem, and removable handles are attached, allowing an astronaut to pull the bi-stem from its cassette. A tethering ring on the outside of the gripping apparatus provides a convenient point to which a lanyard may be attached.

  8. GRIPPING DEVICE FOR CYLINDRICAL OBJECTS

    DOEpatents

    Pilger, J.P.

    1964-01-21

    A gripping device is designed for fragile cylindrical objects such as for drawing thin-walled tubes. The gripping is done by multiple jaw members held in position by two sets of slots, one defined by keystone-shaped extensions of the outer shell of the device and the other in a movable sleeve held slidably by the extensions. Forward movement oi the sleeve advances the jaws, thereby exerting a controlled, radial pressure on the object being gripped. (AEC)

  9. Estimation of grip force using the Grip-ball dynamometer.

    PubMed

    Chkeir, Aly; Jaber, Rana; Hewson, David J; Duchêne, Jacques

    2013-11-01

    The Grip-ball is an innovative device that has been designed to measure grip strength. The Grip-ball consists of an airtight ball that contains a pressure sensor and Bluetooth communication system. The Grip-ball can be inflated to different initial pressures, with data available continuously in real time. The aim of this study was to build a model to predict the force applied to the Grip-ball dynamometer based only on the pressure measured by the Grip-ball and its initial pressure. Forces ranging from 2 to 70 kg were applied to a hybrid version of the device for 10 different initial pressures, ranging from atmospheric pressure of 100 kPa through to 190 kPa. A model was constructed to predict applied force, with force as a function of the initial pressure and the pressure measured. The error of the model was calculated as 1.29 kg across all initial pressures and forces applied. The results of the study are comparable with the errors observed for the gold standard in grip force measurement, the Jamar dynamometer. The best results for force prediction were obtained over the range in which frailty is typically detected. The Grip-ball will now be tested using a large population in order to establish clinical norms.

  10. Computing Gravity's Strongest Grip

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre

    2008-04-01

    Gravitational physics is entering a new era, one driven by observation, that will begin once gravitational wave interferometers such as LIGO make their first detections. The gravitational waves are produced during violent events such as the merger of two black holes. The detection of these waves or ripples in the fabric of spacetime is a formidable undertaking, requiring innovative engineering, powerful data analysis tools and careful theoretical modeling. In support of this theoretical modeling, recent breakthroughs in numerical relativity have lead to the development of computational tools that allow us to explore where and how gravitational wave observations can constrain or inform our understanding of gravity and astrophysical phenomena. I will review these latest developments, focusing on binary black hole simulations and the role these simulations play in our new understanding of physics and astronomy where gravity exhibits its strongest grip on our spacetime.

  11. Mechanical hand for gripping objects

    NASA Technical Reports Server (NTRS)

    Clark, K. H.; Johnston, J. D.

    1980-01-01

    End effector serves as "hand" for remote manipulator spacecraft system to grasp objects of various sizes. Device has built in flexible wrist joint "cartilage" for increased gripping force without significant strain on mechanical connections.

  12. Precision grip and Parkinson's disease.

    PubMed

    Fellows, S J; Noth, J; Schwarz, M

    1998-09-01

    In order to investigate sensorimotor processing and force development in Parkinson's disease, 16 patients, four patients with hemiparkinsonism and 12 age-matched normal subjects were assessed during lifting and holding of an object in a precision grip between thumb and forefinger, or holding the object in this grip at a fixed height above a table. In the former case, object loading could be changed between lifts without warning. In the latter case, unexpected step load changes to the object were applied to the object with a torque motor. All procedures could be applied with or without visual control of the hand and the object. Normal subjects lifted an unpredictable load employing the grip force parameters used in the preceding lift. If a load change was encountered, the parameters became adapted to the new conditions during the lift, modulating grip forces to match the loading. Parkinsonian patients retained this strategy and the ability to regulate grip forces according to load. Under all conditions, however, parkinsonian subjects developed abnormally high grip forces in both the lift and the hold phase, although the ratio of these forces remained normal. Lifting height was normal in parkinsonian subjects, but the duration of the lifting task was significantly prolonged, due to a marked slowing in the rate of grip force development in the lead-up to object lift-off and to prolongation of the movement phase. Forewarning of object loading, with or without visual control, did not reduce timing deficits or improve the rate of grip force development. However, it did allow parkinsonian subjects to reduce the safety margin significantly. Responses to step load changes imposed during holding without visual control showed minor abnormalities in the parkinsonian patients: onset latencies and EMG activity in the first dorsal interosseus and thenar muscles were normal up to 140 ms after displacement. Subsequent EMG activity in the first dorsal interosseus remained largely

  13. Robot Hand Grips Cylinders Securely

    NASA Technical Reports Server (NTRS)

    Parma, George F.

    1989-01-01

    Jaws and linkage accommodate various sizes. Robot hand includes two pairs of parallel jaws that grasp rods, pipes, tubes, struts, and other long, heavy cylindrical objects. Hand features compact rotary drive and butterfly configuration simplifying approach and gripping maneuvers of robot. Parallelogram linkages maintain alignment of each jaw with other jaws. One bar of each linkage connected to one of two concentric, counterrotating shafts; rotation of shafts moves jaws in each pair toward or away from each other to grasp or release workpiece. Each jaw includes rigid gripping pad lined with rubber to give firm grip and to prevent damage to workpiece. Inner cylindrical surface (corner) of each jaw tapers off to flat sides. Enables jaw to grasp workpieces with diameters larger than or equal to twice the corner radius.

  14. Well casing grip assurance system

    SciTech Connect

    Mosing, D.E.; Webre, C.M.

    1987-06-30

    An apparatus is described for assuring that at least one of the elevator or the spider of well casing installation apparatus is fully closed in gripping connection about a well casing before the other of the elevator or the spider may be released from fully closed gripping connection about the well casing, the continuation comprising: (a) two-position elevator valve means connected to admit fluid pressure and to optionally direct it to open and close the elevator; (b) two-position spider valve means connected to admit fluid pressure into the spider and to optionally direct the fluid pressure to open and to close the spider; (c) two-position spider position valve means connected to the elevator valve means. The spider position valve means is mechanically connected for passing the fluid pressure to the elevator valve means only when the spider is fully closed into gripping position; and (d) two-position elevator position valve means connected to the spider valve means. The elevator position valve is mechanically connected to the elevator for passing fluid pressure to the spider valve when the elevator is fully closed into gripping position.

  15. Evaluation of pliers' grip spans in the maximum gripping task and sub-maximum cutting task.

    PubMed

    Kim, Dae-Min; Kong, Yong-Ku

    2016-12-01

    A total of 25 males participated to investigate the effects of the grip spans of pliers on the total grip force, individual finger forces and muscle activities in the maximum gripping task and wire-cutting tasks. In the maximum gripping task, results showed that the 50-mm grip span had significantly higher total grip strength than the other grip spans. In the cutting task, the 50-mm grip span also showed significantly higher grip strength than the 65-mm and 80-mm grip spans, whereas the muscle activities showed a higher value at 80-mm grip span. The ratios of cutting force to maximum grip strength were also investigated. Ratios of 30.3%, 31.3% and 41.3% were obtained by grip spans of 50-mm, 65-mm, and 80-mm, respectively. Thus, the 50-mm grip span for pliers might be recommended to provide maximum exertion in gripping tasks, as well as lower maximum-cutting force ratios in the cutting tasks.

  16. Motor cortical function and the precision grip.

    PubMed

    Geevasinga, Nimeshan; Menon, Parvathi; Kiernan, Matthew C; Vucic, Steve

    2014-12-01

    While task-dependent changes in motor cortical outputs have been previously reported, the issue of whether such changes are specific for complex hand tasks remains unresolved. The aim of the present study was to determine whether cortical inhibitory tone and cortical output were greater during precision grip and power grip. Motor cortex excitability was undertaken by using the transcranial magnetic stimulation threshold tracking technique in 15 healthy subjects. The motor-evoked potential (MEP) responses were recorded over the abductor pollicis brevis (APB), with the hand in the following positions: (1) rest, (2) precision grip and (3) power grip. The MEP amplitude (MEP amplitude REST 23.6 ± 3.3%; MEP amplitude PRECISION GRIP 35.2 ± 5.6%; MEP amplitude POWER GRIP 19.6 ± 3.4%, F = 2.4, P < 0.001) and stimulus-response gradient (SLOPEREST 0.06 ± 0.01; SLOPEPRCISION GRIP 0.15 ± 0.04; SLOPE POWER GRIP 0.07 ± 0.01, P < 0.05) were significantly increased during precision grip. Short interval intracortical inhibition (SICI) was significantly reduced during the precision grip (SICI REST 15.0 ± 2.3%; SICI PRECISION GRIP 9.7 ± 1.5%, SICI POWER GRIP 15.9 ± 2.7%, F = 2.6, P < 0.05). The present study suggests that changes in motor cortex excitability are specific for precision grip, with functional coupling of descending corticospinal pathways controlling thumb and finger movements potentially forming the basis of these cortical changes.

  17. Examinations of factors influencing toe grip strength

    PubMed Central

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya

    2016-01-01

    [Purpose] This study examined the relationship between toe grip strength and its associated factors by focusing on factors that were suggested to have a relationship with toe grip strength in previous studies, aiming to clarify the factors influencing the toe grip strength of healthy women. [Subjects and Methods] Twelve healthy young women were selected for this study. Their toe grip strength, angular changes in their ankle joint during toe grip, maximum voluntary contraction activities of the rectus femoris, biceps femoris, and tibialis anterior muscles, and the medial head of the gastrocnemius muscles were measured using electromyography. Their toe curl ability, foot-arch height ratio, and weight were also measured. [Results] Multiple regression analysis demonstrated that the predictors of toe grip strength in the resulting model were foot-arch height ratio and the percentage of integrated electromyography (%IEMG) of the tibialis anterior muscle, as the dependent variables. This reveals that women whose tibialis anterior muscle %IEMG values and foot-arch height ratio are high have greater %IEMG values have greater toe grip strength. [Conclusion] These findings suggest a significant relationship between foot-arch height ratio and toe grip strength, with a reciprocal interaction. These findings further indicate that the risk of falls by the elderly could be decreased if toe grip strength were enhanced, by increasing the height of a low foot-arch with the help of an inserted insole. PMID:27942134

  18. Examinations of factors influencing toe grip strength.

    PubMed

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya

    2016-11-01

    [Purpose] This study examined the relationship between toe grip strength and its associated factors by focusing on factors that were suggested to have a relationship with toe grip strength in previous studies, aiming to clarify the factors influencing the toe grip strength of healthy women. [Subjects and Methods] Twelve healthy young women were selected for this study. Their toe grip strength, angular changes in their ankle joint during toe grip, maximum voluntary contraction activities of the rectus femoris, biceps femoris, and tibialis anterior muscles, and the medial head of the gastrocnemius muscles were measured using electromyography. Their toe curl ability, foot-arch height ratio, and weight were also measured. [Results] Multiple regression analysis demonstrated that the predictors of toe grip strength in the resulting model were foot-arch height ratio and the percentage of integrated electromyography (%IEMG) of the tibialis anterior muscle, as the dependent variables. This reveals that women whose tibialis anterior muscle %IEMG values and foot-arch height ratio are high have greater %IEMG values have greater toe grip strength. [Conclusion] These findings suggest a significant relationship between foot-arch height ratio and toe grip strength, with a reciprocal interaction. These findings further indicate that the risk of falls by the elderly could be decreased if toe grip strength were enhanced, by increasing the height of a low foot-arch with the help of an inserted insole.

  19. Sugar proximity and human grip strength.

    PubMed

    Quintanar, A F; Hill, T V

    1988-12-01

    In a double-blind experiment with 90 undergraduate students the hypothesis was tested that proximity to sugar reduces human grip strength. An earlier study indicated that sugar proximity does indeed significantly reduce human grip strength. When additional controls were added to this design to reduce random sampling error, the hypothesis was not supported.

  20. MEMS microgrippers with thin gripping tips

    NASA Astrophysics Data System (ADS)

    Chen, Brandon K.; Zhang, Yong; Perovic, Doug D.; Sun, Yu

    2011-10-01

    Gripping small objects requires tool tips of comparable dimensions. Current methods for miniaturizing an MEMS tool entirely down to sub-micrometer in dimensions, however, come with significant tradeoffs in device performance. This paper presents a microfabrication approach to selectively miniaturize gripping tips only to sub-micrometers in thickness. The process involves using the thin buried SiO2 layer of a standard silicon-on-insulator wafer to form gripping tips, and using the thick device silicon layer to construct high-aspect-ratio structures for structural, sensing, and actuation functions. The microgrippers with thin gripping tips (i.e. finger-nail-like) were experimentally characterized and applied to gripping 100 nm gold spheres inside a scanning electron microscope.

  1. Task dependency of grip stiffness--a study of human grip force and grip stiffness dependency during two different tasks with same grip forces.

    PubMed

    Höppner, Hannes; McIntyre, Joseph; van der Smagt, Patrick

    2013-01-01

    It is widely known that the pinch-grip forces of the human hand are linearly related to the weight of the grasped object. Less is known about the relationship between grip force and grip stiffness. We set out to determine variations to these dependencies in different tasks with and without visual feedback. In two different settings, subjects were asked to (a) grasp and hold a stiffness-measuring manipulandum with a predefined grip force, differing from experiment to experiment, or (b) grasp and hold this manipulandum of which we varied the weight between trials in a more natural task. Both situations led to grip forces in comparable ranges. As the measured grip stiffness is the result of muscle and tendon properties, and since muscle/tendon stiffness increases more-or-less linearly as a function of muscle force, we found, as might be predicted, a linear relationship between grip force and grip stiffness. However, the measured stiffness ranges and the increase of stiffness with grip force varied significantly between the two tasks. Furthermore, we found a strong correlation between regression slope and mean stiffness for the force task which we ascribe to a force stiffness curve going through the origin. Based on a biomechanical model, we attributed the difference between both tasks to changes in wrist configuration, rather than to changes in cocontraction. In a new set of experiments where we prevent the wrist from moving by fixing it and resting it on a pedestal, we found subjects exhibiting similar stiffness/force characteristics in both tasks.

  2. GRIPs (Group Investigation Problems) for Introductory Physics

    NASA Astrophysics Data System (ADS)

    Moore, Thomas A.

    2006-12-01

    GRIPs lie somewhere between homework problems and simple labs: they are open-ended questions that require a mixture of problem-solving skills and hands-on experimentation to solve practical puzzles involving simple physical objects. In this talk, I will describe three GRIPs that I developed for a first-semester introductory calculus-based physics course based on the "Six Ideas That Shaped Physics" text. I will discuss the design of the three GRIPs we used this past fall, our experience in working with students on these problems, and students' response as reported on course evaluations.

  3. Heroin Epidemic Expands Its Grip on America

    MedlinePlus

    ... gov/news/fullstory_164350.html Heroin Epidemic Expands Its Grip on America Use of the narcotic grew ... people transition from painkillers to heroin, Martins explained. It is also related to availability, lower cost and ...

  4. NASA Gets 'GRIP' on Hurricane Formation

    NASA Video Gallery

    NASA's GRIP 2010 hurricane mission is in full force. During this year's Atlantic hurricane season, researchers using powerful instruments onboard three aircraft will be able to "see"" below the clo...

  5. Helical grip for the cable cars of San Francisco

    NASA Technical Reports Server (NTRS)

    Peyran, R. J.

    1979-01-01

    A helical cable car grip to minimize high maintenance costs of San Francisco's cable car operation is presented. The grip establishes a rolling contact between the cable and grip to reduce sliding friction and associated cable wear. The design, development, and testing of the helical cable car grip are described.

  6. Design and validation of the Grip-ball for measurement of hand grip strength.

    PubMed

    Jaber, Rana; Hewson, David J; Duchêne, Jacques

    2012-11-01

    The Grip-ball is a new dynamometer used to evaluate grip strength, as well as for use in home-based rehabilitation of the hand and forearm. The Grip-ball consists of pressure and temperature sensors and an electronic wireless communication system contained in an airtight ball. That can be inflated to different pressures. The device has advantages over standard dynamometers in that it looks like a simple ball, and can wirelessly communicate via Bluetooth to any compatible receiver, thus have potential to be used for clinical assessment and rehabilitation in a remote setting. The reliability and reproducibility of the device were assessed for the pressure sensor itself, as well as the relationship between the force applied and the pressure measured by the Grip-ball. The initial validation was performed using the pressure sensor without the ball in order to confirm the accuracy of the sensor used. A second validation study was conducted using the Grip-ball rather than just its sensor to examine the relationship between the pressure measured inside the ball and force applied. The results showed that there is a very good correlation (r=0.997, p<0.05) between the pressure measured by the Grip-ball sensor and that measured by a Vigorimeter, thus confirming the reliability of the sensor used in the Grip-ball. A quadratic regression equation was calculated in order to predict the force applied based on the pressure measured inside the ball, and the initial pressure to which the ball was inflated (R(2)=0.97, standard error 10.9N). Such a finding compares favourably with the variability inherent in Jamar recordings, thus indicating that the Grip-ball could be used to assess grip force. An industrial version of the Grip-ball, which is currently under development, will be able to be used for the entire range of grip force in the population.

  7. GRIPS - The Geostationary Remote Infrared Pollution Sounder

    NASA Astrophysics Data System (ADS)

    Spackman, Ryan; Dickerson, Russell; Schoeberl, Mark; Bloom, Hal; Gordley, Larry; McHugh, Martin; Thompson, Anne; Burrows, John; Zeng, Ning; Marshall, Tom; Fish, Chad; Kim, Jhoon; Park, Rokjin; Warner, Juying; Bhartia, Pawan; Kollonige, Debra

    2013-04-01

    Climate change and air quality are the most pressing environmental issues of the 21st century for America and for the world as a whole. Despite decades of research, the sources and sinks of key greenhouse gases and other pollutants remain highly uncertain making atmospheric composition predictions difficult. The Geostationary Remote Infrared Pollution Sounder (GRIPS) will measure carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). By using measurements of nitrous oxide (N2O) and the O2 A-band to help correct for clouds and aerosols, GRIPS will achieve unprecedented precision. Together these gases account for about 85% of all climate forcing and they impact atmospheric ozone (O3). GRIPS, employing gas-filter correlation radiometry, uses the target gases themselves in place of dispersive elements to achieve outstanding throughput, sensitivity, and specificity. Because it uses a combination of reflected and thermal IR, GRIPS will detect trace gas concentrations right down to the Earth's surface. When flown in parallel to a UV/VIS sensor such as GEMS on GEO-KOMPSAT-2B over East Asia or the Sentinel 4 on MTG over Europe/Africa, the combination offers powerful finger-printing capabilities to distinguish and quantify diverse pollution sources such as electricity generation, biomass burning, and motor vehicles. From geostationary orbit, GRIPS will be able to focus on important targets to quantify sources, net flux, diurnal cycles, and long-range transport of these key components in the Earth's radiative balance and air quality.

  8. GRIPS - The Geostationary Remote Infrared Pollution Sounder

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Schoeberl, M. R.; Gordley, L. L.; McHugh, M. J.; Thompson, A. M.; Burrows, J. P.; Zeng, N.; Marshall, B. T.; Fish, C. S.; Spackman, J. R.; Kim, J.; Park, R.; Warner, J. X.; Bhartia, P. K.; Kollonige, D. E.

    2012-12-01

    Climate change and air quality are the most pressing environmental issues of the 21st century - for America and for the world as a whole. Despite decades of research, the sources and sinks of key greenhouse gases and other pollutants remain highly uncertain making atmospheric composition predictions difficult. The Geostationary Remote Infrared Pollution Sounder (GRIPS) will measure carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). By using measurements of nitrous oxide (N2O) and the O2 A-band to help correct for clouds and aerosols, GRIPS will achieve unprecedented precision. Together these gases account for about 85% of all climate forcing and they impact atmospheric ozone (O3). GRIPS, employing gas-filter correlation radiometry, uses the target gases themselves in place of dispersive elements to achieve outstanding throughput, sensitivity, and specificity. Because it uses a combination of reflected and thermal IR, GRIPS will detect trace gas concentrations right down to the Earth's surface. When flown in parallel to a UV/VIS sensor such as GEMS on GEO-KOMPSAT-2B over East Asia or the Sentinel 4 on MTG over Europe/Africa, the combination offers powerful finger-printing capabilities to distinguish and quantify diverse pollution sources such as electricity generation, biomass burning, and motor vehicles. From geostationary orbit, GRIPS will be able to focus on important targets to quantify sources, net flux, diurnal cycles, and long-range transport of these key components in the Earth's radiative balance and air quality.

  9. 23. POWELLTYPE CAR THROUGH GRIP REMOVAL DOOR: View looking through ...

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

    23. POWELL-TYPE CAR THROUGH GRIP REMOVAL DOOR: View looking through grip removal door into interior of a Powell-type cable car. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  10. Tool Would Grip Round Electrical Connectors

    NASA Technical Reports Server (NTRS)

    Camarata, Terrence L.

    1992-01-01

    Proposed version of commercially available tool makes it easier to mate and demate round, bayonet-mount, multipin electrical connectors in densely populated connector panels without removing adjacent connectors. Inner surface of cylindrical shell smooth with tapered lip gripping knurled outer ring on connector.

  11. Effect of elbow flexion, forearm rotation and upper arm abduction on MVC grip and grip endurance time.

    PubMed

    Farooq, Mohd; Khan, Abid Ali

    2012-01-01

    This experiment was designed to know the effect of upper limb postural deviations on grip strength and grip endurance time. A full factorial design of experiment, i.e., 3 (0°, 45°, 90° abduction angles of upper arm) × 3 (45°, 90°, 135° angles of elbow flexion) × 3 (0°, -60° prone, +60° supine angles of forearm rotation) was used to find the effect of 27 combinations of postures on maximum voluntary contraction (MVC) grip strength and grip endurance time. The results showed that none of the main factors were significant on MVC grip, although there was a change in MVC grip. Grip endurance time significantly decreased with an increase in upper arm abduction. Also, grip endurance significantly increased with the elbow flexion angle and decreased with forearm rotation from neutral. These data will help designers and engineers to improve the workplace and tools to reduce the risk of injuries.

  12. Variability of grip kinetics during adult signature writing.

    PubMed

    Ghali, Bassma; Thalanki Anantha, Nayanashri; Chan, Jennifer; Chau, Tom

    2013-01-01

    Grip kinetics and their variation are emerging as important considerations in the clinical assessment of handwriting pathologies, fine motor rehabilitation, biometrics, forensics and ergonomic pen design. This study evaluated the intra- and inter-participant variability of grip shape kinetics in adults during signature writing. Twenty (20) adult participants wrote on a digitizing tablet using an instrumented pen that measured the forces exerted on its barrel. Signature samples were collected over 10 days, 3 times a day, to capture temporal variations in grip shape kinetics. A kinetic topography (i.e., grip shape image) was derived per signature by time-averaging the measured force at each of 32 locations around the pen barrel. The normalized cross correlations (NCC) of grip shape images were calculated within- and between-participants. Several classification algorithms were implemented to gauge the error rate of participant discrimination based on grip shape kinetics. Four different grip shapes emerged and several participants made grip adjustments (change in grip shape or grip height) or rotated the pen during writing. Nonetheless, intra-participant variation in grip kinetics was generally much smaller than inter-participant force variations. Using the entire grip shape images as a 32-dimensional input feature vector, a K-nearest neighbor classifier achieved an error rate of 1.2±0.4% in discriminating among participants. These results indicate that writers had unique grip shape kinetics that were repeatable over time but distinct from those of other participants. The topographic analysis of grip kinetics may inform the development of personalized interventions or customizable grips in clinical and industrial applications, respectively.

  13. Kinetics of crimp and slope grip in rock climbing.

    PubMed

    Schweizer, Andreas; Hudek, Robert

    2011-05-01

    The aim was to investigate differences of the kinetics of the crimp and the slope grip used in rock climbing. Nine cadaver fingers were prepared and fixated with the proximal phalanx in a frame. The superficial (FDS) and deep (FDP) flexor tendons were loaded selectively and together with 40 N in the crimp grip (PIP joint flexed 90°/DIP joint hyperextended) and the slope grip position (<25° flexed/50° flexed respectively). Five different grip sizes were tested and the flexion force which was generated to the grip was measured. In the crimp grip the FDP generated more flexion force in small sized holds whereas the FDS generated more force in the larger holds. During the slope grip the FDP was more effective than the FDS. While both tendons were loaded, the flexion force was always greater during crimp grip compared with the slope grip. The FDP seems to be most important for very small holds using the crimp grip but also during slope grip holds whereas the FDS is more important for larger flat holds.

  14. Risky Business: Get a Grip On It

    NASA Astrophysics Data System (ADS)

    Cober, P.

    This paper focuses on the use of requirements as an efficient and effective way to get a grip on the risks of your software. It references on the good practices that are used in the pharmaceutical industry. It is, like the space industry, confronted with very high risks. The cost when anything goes wrong is tremendously, not only for the company itself but also the intangible cost if human health is at stake. Therefore both industries are severely regulated through several official bodies.

  15. Effect of grip strength and grip strengthening exercises on instantaneous bat velocity of collegiate baseball players.

    PubMed

    Hughes, Shawn S; Lyons, Brian C; Mayo, Jerry J

    2004-05-01

    Bat velocity is considered to be an important factor for successful hitting. The relationship between grip strength and bat velocity has not been conclusively established. The purposes of this study were to determine the relationship of grip strength to bat velocity and to ascertain whether the performance of resistance training exercises designed to specifically target the forearms and grip would significantly alter bat velocity. The subjects for this study were 23 male members (mean +/- SD, age = 19.7 +/- 1.3 years, height = 182.5 +/- 5.9 cm, weight = 85.4 +/- 15.5 kg, experience = 14.4 +/- 1.7 years) of a varsity baseball team at a National Collegiate Athletic Association Division II school. The Jamar hand dynamometer was used to test grip strength, and the SETPRO Rookie was used to measure instantaneous bat velocity at the point of contact with the ball. Subjects were randomly divided into an experimental group and a control group. For 6 weeks, both groups participated in their usual baseball practice sessions, but the experimental group also performed extra forearm and grip strengthening exercises, whereas the control group did not. Pretest and posttest correlations between grip strength and bat velocity revealed no significant relationship between grip strength and bat velocity (pretest r = 0.054, p = 0.807; posttest r = 0.315, p = 0.145). A dependent t-test performed on all subjects revealed that a significant (p = 0.001) increase in bat velocity did occur over the course of the study. A covariate analysis, employing pretest bat velocity as the covariate, revealed no significant difference (p = 0.795) in posttest bat velocity scores between the experimental and control groups. Thus, increases in bat velocity occurred, but the differences were similar for both the experimental and control groups. The findings of this study suggest that grip strength and bat velocity are not significantly related, and that the allocation of time and energy for added training

  16. Development of an integrated digital hand grip dynamometer and norm of hand grip strength.

    PubMed

    Chang, Ho; Chen, Chih-Hao; Huang, Tung-Sun; Tai, Chun-Yen

    2015-01-01

    This study designs and fabricates a novel integrated digital hand grip dynamometer and analyzes collected grip strength data. The dynamometer directly stores collected data in a computer, unlike those on the market that cannot directly store information. A strain gauge load cell is used as a force sensor. The dynamometer is designed to maximize ergonomics. Excitation voltage of the load cell is 5 V, and a 9 V battery supplies power to its circuit. The signal receiver is National Instruments (NI) data acquisition (DAQ) card that transmits signals to the computer. The operation system is designed using LabView. This study assesses the correlation between variables of collected data. The correlation coefficients for height, weight and palm length were 0.793, 0.609 and 0.715, respectively, indicating that variables were moderately to strongly correlate with grip strength.

  17. Systems and Methods for Gravity-Independent Gripping and Drilling

    NASA Technical Reports Server (NTRS)

    Parness, Aaron (Inventor); Frost, Matthew A. (Inventor); Thatte, Nitish (Inventor); King, Jonathan P. (Inventor)

    2016-01-01

    Systems and methods for gravity independent gripping and drilling are described. The gripping device can also comprise a drill or sampling devices for drilling and/or sampling in microgravity environments, or on vertical or inverted surfaces in environments where gravity is present. A robotic system can be connected with the gripping and drilling devices via an ankle interface adapted to distribute the forces realized from the robotic system.

  18. Microspine Gripping Mechanism for Asteroid Capture

    NASA Technical Reports Server (NTRS)

    Merriam, Ezekiel G.; Berg, Andrew B.; Willig, Andrew; Parness, Aaron; Frey, Tim; Howell, Larry L.

    2016-01-01

    This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to grasp irregularly shaped boulders in micro-gravity.

  19. Grip strength and forearm circumference in a healthy population.

    PubMed

    Anakwe, R E; Huntley, J S; McEachan, J E

    2007-04-01

    Two hundred and fifty subjects were recruited. Age, sex, hand preference and anthropometric measurements were recorded for each subject. Grip strength was measured using a Jamar hydraulic dynamometer. Multiple regression analyses were performed. One hundred and seventy two subjects were men and 78 were women. Twenty-six subjects were left hand dominant. Hand grip strength was greatest for the 35 to 44 year old group for both sexes. Grip strength was consistently greater for men than women. Contralateral grip strength predicted maximum grip strength for both sexes. Forearm circumference predicted maximum hand grip strength for men. Although there was a large range of forearm circumferences in the population, there was little difference between sides for each subject (100% less than 2 cm). The demonstrated relationships between: (i) contralateral grip strengths and (ii) grip strength and forearm circumference lead us to suggest that for certain pathologies, a difference in forearm circumference greater than 2 cm may lend credence to a measurement of diminished grip strength.

  20. Optimization of the levels of grip force, stroke rotation, frequency and grip span for a torqueing task.

    PubMed

    Bano, Farheen; Mallick, Zulqernian; Ali Khan, Abid

    2015-01-01

    This study was to investigate the effects of grip force, frequency, stroke rotation and grip-span on discomfort and obtain best posture for hand tool users. Fifteen male participants volunteered in this study. Participants performed combined gripping with torqueing exertions for 5 min for two levels of frequency (10 and 20 exertions/min) at two levels of grip force (50 and 70 N), two levels of stroke rotation (30(○) and 60(○)) and three levels of grip-span (4.7, 6 and 7.3 cm). Therefore, a 2×2×2×3 full factorial design was used. The analysis of variance (ANOVA) showed that frequency, stroke rotation and grip-span were significant on discomfort score. Minimum discomfort and comfortable posture was found to be 90 N grip force with 10 exertions/min for 60° stroke rotation at 6-cm grip-span. The grip force, frequency and stroke rotation were found significant on EMG activity of forearm muscles using multivariate analysis of variance (MANOVA). The extensor muscles were found more activated than flexor muscles during the given task.

  1. ALTERED PHALANX FORCE DIRECTION DURING POWER GRIP FOLLOWING STROKE

    PubMed Central

    Enders, Leah R.

    2015-01-01

    Many stroke survivors with severe impairment can grasp only with a power grip. Yet, little knowledge is available on altered power grip after stroke, other than reduced power grip strength. This study characterized stroke survivors’ static power grip during 100% and 50% maximum grip. Each phalanx force’s angular deviation from the normal direction and its contribution to total normal force was compared for 11 stroke survivors and 11 age-matched controls. Muscle activities and skin coefficient of friction (COF) were additionally compared for another 20 stroke and 13 age-matched control subjects. The main finding was that stroke survivors gripped with a 34% greater phalanx force angular deviation of 19±2° compared to controls of 14±1° (p<.05). Stroke survivors’ phalanx force angular deviation was closer to the 23° threshold of slippage between the phalanx and grip surface, which may explain increased likelihood of object dropping in stroke survivors. In addition, this altered phalanx force direction decreases normal grip force by tilting the force vector, indicating a partial role of phalanx force angular deviation in reduced grip strength post stroke. Greater phalanx force angular deviation may biomechanically result from more severe underactivation of stroke survivors’ first dorsal interosseous (FDI) and extensor digitorum communis (EDC) muscles compared to their flexor digitorum superficialis (FDS) or somatosensory deficit. While stroke survivors’ maximum power grip strength was approximately half of the controls’, the distribution of their remaining strength over the fingers and phalanges did not differ, indicating evenly distributed grip force reduction over the entire hand. PMID:25795079

  2. Self-selected duty cycle times for grip force, wrist flexion postures and three grip types.

    PubMed

    Finneran, Aoife; O'Sullivan, Leonard

    2014-01-01

    Performance and health issues are common in industry. On-the-job productivity gains related to good design, which could help justify ergonomics intervention, are often not considered. More quantitative data are needed to model the discomfort/productivity relationship for upper limb activity in simulated repetitive assembly type work. Eighteen participants completed an experiment, simulating a repetitive upper limb task with force, posture and grip type recorded as independent variables. Duty cycle time and discomfort were recorded as dependent variables. Participants performed 18 experiment combinations (block designed around force); each treatment lasted 35 min, including breaks. Analysis indicated a significant two-way interaction between posture and grip type. Results from this experiment were used to model the effect of these variables on operator discomfort and performance.

  3. Proximal arm kinematics affect grip force-load force coordination.

    PubMed

    Vermillion, Billy C; Lum, Peter S; Lee, Sang Wook

    2015-10-01

    During object manipulation, grip force is coordinated with load force, which is primarily determined by object kinematics. Proximal arm kinematics may affect grip force control, as proximal segment motion could affect control of distal hand muscles via biomechanical and/or neural pathways. The aim of this study was to investigate the impact of proximal kinematics on grip force modulation during object manipulation. Fifteen subjects performed three vertical lifting tasks that involved distinct proximal kinematics (elbow/shoulder), but resulted in similar end-point (hand) trajectories. While temporal coordination of grip and load forces remained similar across the tasks, proximal kinematics significantly affected the grip force-to-load force ratio (P = 0.042), intrinsic finger muscle activation (P = 0.045), and flexor-extensor ratio (P < 0.001). Biomechanical coupling between extrinsic hand muscles and the elbow joint cannot fully explain the observed changes, as task-related changes in intrinsic hand muscle activation were greater than in extrinsic hand muscles. Rather, between-task variation in grip force (highest during task 3) appears to contrast to that in shoulder joint velocity/acceleration (lowest during task 3). These results suggest that complex neural coupling between the distal and proximal upper extremity musculature may affect grip force control during movements, also indicated by task-related changes in intermuscular coherence of muscle pairs, including intrinsic finger muscles. Furthermore, examination of the fingertip force showed that the human motor system may attempt to reduce variability in task-relevant motor output (grip force-to-load force ratio), while allowing larger fluctuations in output less relevant to task goal (shear force-to-grip force ratio).

  4. Predicting maximal grip strength using hand circumference.

    PubMed

    Li, Ke; Hewson, David J; Duchêne, Jacques; Hogrel, Jean-Yves

    2010-12-01

    The objective of this study was to analyze the correlations between anthropometric data and maximal grip strength (MGS) in order to establish a simple model to predict "normal" MGS. Randomized bilateral measurement of MGS was performed on a homogeneous population of 100 subjects. MGS was measured according to a standardized protocol with three dynamometers (Jamar, Myogrip and Martin Vigorimeter) for both dominant and non-dominant sides. Several anthropometric data were also measured: height; weight; hand, wrist and forearm circumference; hand and palm length. Among these data, hand circumference had the strongest correlation with MGS for all three dynamometers and for both hands (0.789 and 0.782 for Jamar; 0.829 and 0.824 for Myogrip; 0.663 and 0.730 for Vigorimeter). In addition, the only anthropometric variable systematically selected by a stepwise multiple linear regression analysis was also hand circumference. Based on this parameter alone, a predictive regression model presented good results (r(2) = 0.624 for Jamar; r(2) = 0.683 for Myogrip and r(2) = 0.473 for Vigorimeter; all adjusted r(2)). Moreover a single equation was predictive of MGS for both men and women and for both non-dominant and dominant hands. "Normal" MGS can be predicted using hand circumference alone.

  5. Basal Ganglia Mechanisms Underlying Precision Grip Force Control

    PubMed Central

    Prodoehl, Janey; Corcos, Daniel M.; Vaillancourt, David E.

    2009-01-01

    The classic grasping network has been well studied but thus far the focus has been on cortical regions in the control of grasping. Sub-cortically, specific nuclei of the basal ganglia have been shown to be important in different aspects of precision grip force control but these findings have not been well integrated. In this review we outline the evidence to support the hypothesis that key basal ganglia nuclei are involved in parameterizing specific properties of precision grip force. We review literature from different areas of human and animal work that converges to build a case for basal ganglia involvement in the control of precision gripping. Following on from literature showing anatomical connectivity between the basal ganglia nuclei and key nodes in the cortical grasping network, we suggest a conceptual framework for how the basal ganglia could function within the grasping network, particularly as it relates to the control of precision grip force. PMID:19428499

  6. Effect of Lateral Epicondylosis on Grip Force Development

    PubMed Central

    Chourasia, Amrish O.; Buhr, Kevin A.; Rabago, David P.; Kijowski, Richard; Irwin, Curtis B.; Sesto, Mary E.

    2012-01-01

    Introduction While it is well known that grip strength is adversely affected by lateral epicondylosis (LE), the effect of LE on rapid grip force generation is unclear. Purpose The purpose of this study was to evaluate the effect of LE on the ability to rapidly generate grip force. Methods Twenty-eight participants with LE (13 unilateral and 15 bilateral LE) and 13 healthy controls participated in this study. A Multi-Axis Profile dynamometer was used to evaluate grip strength and rapid grip force generation. The ability to rapidly produce force is comprised of the electromechanical delay and rate of force development. Electromechanical delay is defined as the time between the onset of electrical activity and the onset of muscle force production. The Patient Rated Tennis Elbow Evaluation (PRTEE) questionnaire was used to assess pain and functional disability. Magnetic resonance imaging was used to evaluate tendon degeneration. Results LE-injured upper extremities had lower rate of force development (−50 lbs/sec, CI [−17, −84]) and less grip strength (−7.8 lbs, CI [−3.3, −12.4]) than non-injured extremities. Participants in the LE group had a longer electromechanical delay (+59%, CI [29,97]) than controls. Peak rate of force development had a higher correlation (r=0.56)(p<0.05) with PRTEE function than grip strength (r=0.47) (p<0.05) and electromechanical delay (r=0.30)(p>0.05) for participants with LE. Conclusion In addition to a reduction in grip strength, those with LE had a reduction in rate of force development and an increase in electromechanical delay. Collectively, these changes may contribute to an increase in reaction time, which may affect risk for recurrent symptoms. These findings suggest that therapists may need to address both strength and rapid force development deficits in patients with LE. PMID:22137195

  7. Subcortical control of precision grip after human spinal cord injury.

    PubMed

    Bunday, Karen L; Tazoe, Toshiki; Rothwell, John C; Perez, Monica A

    2014-05-21

    The motor cortex and the corticospinal system contribute to the control of a precision grip between the thumb and index finger. The involvement of subcortical pathways during human precision grip remains unclear. Using noninvasive cortical and cervicomedullary stimulation, we examined motor evoked potentials (MEPs) and the activity in intracortical and subcortical pathways targeting an intrinsic hand muscle when grasping a small (6 mm) cylinder between the thumb and index finger and during index finger abduction in uninjured humans and in patients with subcortical damage due to incomplete cervical spinal cord injury (SCI). We demonstrate that cortical and cervicomedullary MEP size was reduced during precision grip compared with index finger abduction in uninjured humans, but was unchanged in SCI patients. Regardless of whether cortical and cervicomedullary stimulation was used, suppression of the MEP was only evident 1-3 ms after its onset. Long-term (∼5 years) use of the GABAb receptor agonist baclofen by SCI patients reduced MEP size during precision grip to similar levels as uninjured humans. Index finger sensory function correlated with MEP size during precision grip in SCI patients. Intracortical inhibition decreased during precision grip and spinal motoneuron excitability remained unchanged in all groups. Our results demonstrate that the control of precision grip in humans involves premotoneuronal subcortical mechanisms, likely disynaptic or polysynaptic spinal pathways that are lacking after SCI and restored by long-term use of baclofen. We propose that spinal GABAb-ergic interneuronal circuits, which are sensitive to baclofen, are part of the subcortical premotoneuronal network shaping corticospinal output during human precision grip.

  8. Overlapping representations for grip type and reach direction.

    PubMed

    Fabbri, Sara; Strnad, Lukas; Caramazza, Alfonso; Lingnau, Angelika

    2014-07-01

    To grasp an object, we need to move the arm toward it and assume the appropriate hand configuration. While previous studies suggested dorsomedial and dorsolateral pathways in the brain specialized respectively for the transport and grip components, more recent studies cast doubt on such a clear-cut distinction. It is unclear, however, to which degree neuronal populations selective for the two components overlap, and if so, to which degree they interact. Here, we used multivoxel pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) data to investigate the representation of three center-out movements (touch, pincer grip, whole-hand grip) performed in five reach directions. We found selectivity exclusively for reach direction in posterior and rostral superior parietal lobes (SPLp, SPLr), supplementary motor area (SMA), and the superior portion of dorsal premotor cortex (PMDs). Instead, we found selectivity for both grip type and reach direction in the inferior portion of dorsal premotor cortex (PMDi), ventral premotor cortex (PMv), anterior intraparietal sulcus (aIPS), primary motor (M1), somatosensory (S1) cortices and the anterior superior parietal lobe (SPLa). Within these regions, PMv, M1, aIPS and SPLa showed weak interactions between the transport and grip components. Our results suggest that human PMDi and S1 contain both grip- and reach-direction selective neuronal populations that retain their functional independence, whereas this information might be combined at the level of PMv, M1, aIPS, and SPLa.

  9. Effect of Syllable Articulation on Precision and Power Grip Performance

    PubMed Central

    Vainio, Lari; Schulman, Mirjam; Tiippana, Kaisa; Vainio, Martti

    2013-01-01

    The present study was motivated by a theory, which proposes that speech includes articulatory gestures that are connected to particular hand actions. We hypothesized that certain articulatory gestures would be more associated with the precision grip than with the power grip, and vice versa. In the study, the participants pronounced a syllable and performed simultaneously a precision or power grip that was theorized to be either congruent or incongruent with the syllable. Relatively fast precision grip responses were associated with articulatory gestures in which the tip of the tongue contacted the alveolar ridge ([te]) or the aperture of the vocal tract remained small ([hi]), as well as gestures that required lip protrusion ([pu]). In contrast, relatively fast power grip responses were associated with gestures that were produced by moving the back of the tongue against the velum ([ke]) or in which the aperture of the vocal tract remained large ([hα]). In addition to demonstrating that certain articulatory gestures are systematically connected to different grip types, the study may shed some light on discussion concerning sound symbolism and evolution of speech. PMID:23326381

  10. Subtle grip force estimation from EMG and muscle stiffness--relationship between muscle character frequency and grip force.

    PubMed

    Kasuya, Masahiro; Seki, Masatoshi; Kawamura, Kazuya; Fujie, Masakatsu G

    2011-01-01

    A number of upper limb amputees experience difficulty in picking up a food bowl during a meal, because grip force estimation using EMG currently does not provide sufficient accuracy for this task. In this paper, we propose a grip force estimation system that allows amputees to pick up a bowl with a prosthetic hand by using the properties of muscle stiffness in addition to EMG. We have chosen a tray holding task to evaluate the proposed system. A weight is dropped on the tray and the subjects are expected to control the tray's attitude during the task. Actual grip force, EMG, and muscle stiffness are measured, and the actual measured grip force is compared with the estimated grip force for evaluation. As a result, the proposed algorithm is found to be able to estimate grip force with an error of just 18[N], which is 30% smaller than in the method that uses only EMG. From the result that the response time estimated by proposed system is even less than a human's mechanical reaction time, the effectiveness of the proposed method has been validated.

  11. Association of grip strength with cardiovascular risk markers.

    PubMed

    Gubelmann, Cédric; Vollenweider, Peter; Marques-Vidal, Pedro

    2017-03-01

    Background Mechanisms underlying the association between grip strength and cardiovascular mortality are poorly understood. We aimed to assess the association of grip strength with a panel of cardiovascular risk markers. Design The study was based on a cross-sectional analysis of 3468 adults aged 50-75 years (1891 women) from a population-based sample in Lausanne, Switzerland. Methods Grip strength was measured using a hydraulic hand dynamometer. Cardiovascular risk markers included anthropometry, blood pressure, lipids, glucose, adiposity, inflammatory and other metabolic markers. Results In both genders, grip strength was negatively associated with fat mass (Pearson correlation coefficient: women: -0.170, men: -0.198), systolic blood pressure (women: -0.096, men: -0.074), fasting glucose (women: -0.048, men: -0.071), log-transformed leptin (women: -0.074, men: -0.065), log-transformed high-sensitivity C-reactive protein (women: -0.101, men: -0.079) and log-transformed homocysteine (women: -0.109, men: -0.060). In men, grip strength was also positively associated with diastolic blood pressure (0.068), total (0.106) and low density lipoprotein-cholesterol (0.082), and negatively associated with interleukin-6 (-0.071); in women, grip strength was negatively associated with triglycerides (-0.064) and uric acid (-0.059). After multivariate adjustment, grip strength was negatively associated with waist circumference (change per 5 kg increase in grip strength: -0.82 cm in women and -0.77 cm in men), fat mass (-0.56% in women; -0.27% in men) and high-sensitivity C-reactive protein (-6.8% in women; -3.2% in men) in both genders, and with body mass index (0.22 kg/m(2)) and leptin (-2.7%) in men. Conclusion Grip strength shows only moderate associations with cardiovascular risk markers. The effect of muscle strength as measured by grip strength on cardiovascular disease does not seem to be mediated by cardiovascular risk markers.

  12. The influence of the crimp and slope grip position on the finger pulley system.

    PubMed

    Schöffl, I; Oppelt, K; Jüngert, J; Schweizer, A; Neuhuber, W; Schöffl, V

    2009-09-18

    In this study the influence of the grip position (crimp grip vs. slope grip position) on the pulley system of the finger was investigated. For this purpose 21 cadaver finger (11 hands, 10 donors) were fixed into an isokinetic loading device. Nine fingers were loaded in the slope grip position and 12 fingers in the crimp grip position. The forces in the flexor tendons and at the fingertip were recorded. A rupture of the A4 pulley occurred most often in the crimp grip position (50%) but did not occur in the slope grip position, in which alternative events were the most common (67%). The forces in the deep flexor tendon (FDP) (slope grip: 371 N, crimp grip: 348 N) and at the fingertip (slope grip: 105 N, crimp grip: 161 N) were not significantly different between the 2 finger positions, but the forces acting on the pulleys were higher in the crimp grip position (A2 pulley: 287 N, A4 pulley: 226 N) than in the slope grip position (A2 pulley: 121 N, A4 pulley: 103 N). The crimp grip position may be the main cause for A4 pulley ruptures but the slope grip position may be hazardous for other injuries as the forces recorded in the flexor tendons and at the fingertip were comparable at the occurrence of a terminal event.

  13. Grip forces exerted against stationary held objects during gravity changes.

    PubMed

    Hermsdörfer, J; Marquardt, C; Philipp, J; Zierdt, A; Nowak, D; Glasauer, S; Mai, N

    1999-05-01

    In the present study, grip forces exerted against a stationary held object were recorded during parabolic flights. Such flight maneuvers induce changes of gravity with two periods of hypergravity, associated with a doubling of normal terrestrial gravity, and a 20 s period of microgravity. Accordingly, the object's weight changed from being twice as heavy as normally experienced and weightless. Grip-force recordings demonstrated that force control was seriously disturbed only during the first experience of hyper- and microgravity, with the grip forces being exceedingly high and yielding irregular fluctuations. Thereafter, however, grip force traces were smooth, the force level was scaled to the object's weight under normal and high-G conditions, and the grip force changed in parallel with the weight during the transitions between hyper- and microgravity. In addition, during weightlessness, when virtually no force was necessary to stabilize the object, a low force was established, which obviously represented a reasonable safety margin for preventing possible perturbations. Thus, all relevant aspects of grip-force control observed under normal gravity conditions were preserved during gravity changes induced by parabolic flights. Hence, grip-force control mechanisms were able to cope with hyper- and microgravity, either by incorporating relevant receptor signals, such as those originating from cutaneous mechanoreceptors, or by adequately including perceived gravity signals into control programs. However, the adaptation to the uncommon gravity conditions was not complete following the first experience; finer tuning of the control system to both hyper- and microgravity continued over the measurement interval, presumably with a longer observation period being necessary before a stable performance can be reached.

  14. Effect of toothbrush grip on plaque removal during manual toothbrushing in children.

    PubMed

    Sharma, Sarika; Yeluri, Ramakrishna; Jain, Amit A; Munshi, Autar K

    2012-01-01

    Toothbrushing is fundamental to oral hygiene. Children differ in manual dexterity and their grip on toothbrushes. We videotaped toothbrushing sessions and observed the grip type, duration of brushing, and brushing technique used among 100 children aged 8-12 years. We then investigated the association between grip type and plaque removal, using plaque scores obtained at various time points. We further examined the effect on plaque scores of standardizing both brushing technique and duration among the same participants. The most common grip was the distal oblique, followed by the oblique; the spoon and precision grips were rare, and no child used a power grip. Mean brushing duration for most children was 1.43 ± 0.85 min, and the most common brushing technique was horizontal scrubbing. We conclude that grip preference is inherent and that the distal oblique grip was better than the oblique grip in removing plaque.

  15. GRIP Collaboration Portal: Information Management for a Hurricane Field Campaign

    NASA Astrophysics Data System (ADS)

    Conover, H.; Kulkarni, A.; Garrett, M.; Smith, T.; Goodman, H. M.

    2010-12-01

    NASA’s Genesis and Rapid Intensification Processes (GRIP) experiment, carried out in August and September of 2010, was a complex operation, involving three aircraft and their crews based at different airports, a dozen instrument teams, mission scientists, weather forecasters, project coordinators and a variety of other participants. In addition, GRIP was coordinated with concurrent airborne missions: NOAA’s IFEX and then NSF-funded PREDICT. The GRIP Collaboration Portal was developed to facilitate communication within and between the different teams and serve as an information repository for the field campaign, providing a single access point for project documents, plans, weather forecasts, flight reports and quicklook data. The portal was developed using the Drupal open source content management framework. This presentation will cover both technology and participation issues. Specific examples include: Drupal’s large and diverse open source developer community is an advantage in that we were able to reuse many modules rather than develop capabilities from scratch, but integrating multiple modules developed by many people adds to the overall complexity of the site. Many of the communication capabilities provided by the site, such as discussion forums and blogs, were not used. Participants were diligent about posting necessary documents, but the favored communication method remained email. Drupal's developer-friendly nature allowed for quick development of the customized functionality needed to accommodate the rapidly changing requirements of GRIP experiment. DC-8 Overflight of Hurricane Earl during GRIP Mission

  16. GRIP1 is required for homeostatic regulation of AMPAR trafficking

    PubMed Central

    Tan, Han L.; Queenan, Bridget N.; Huganir, Richard L.

    2015-01-01

    Homeostatic plasticity is a negative feedback mechanism that stabilizes neurons during periods of perturbed activity. The best-studied form of homeostatic plasticity in the central nervous system is the scaling of excitatory synapses. Postsynaptic AMPA-type glutamate receptors (AMPARs) can be inserted into synapses to compensate for neuronal inactivity or removed to compensate for hyperactivity. However, the molecular mechanisms underlying the homeostatic regulation of AMPARs remain elusive. Here, we show that the expression of GRIP1, a multi-PDZ (postsynaptic density 95/discs large/zona occludens) domain AMPAR-binding protein, is bidirectionally altered by neuronal activity. Furthermore, we observe a subcellular redistribution of GRIP1 and a change in the binding of GRIP1 to GluA2 during synaptic scaling. Using a combination of biochemical, genetic, and electrophysiological methods, we find that loss of GRIP1 blocks the accumulation of surface AMPARs and the scaling up of synaptic strength that occur in response to chronic activity blockade. Collectively, our data point to an essential role of GRIP1-mediated AMPAR trafficking during inactivity-induced synaptic scaling. PMID:26216979

  17. Biometric verification based on grip-pattern recognition

    NASA Astrophysics Data System (ADS)

    Veldhuis, Raymond N.; Bazen, Asker M.; Kauffman, Joost A.; Hartel, Pieter

    2004-06-01

    This paper describes the design, implementation and evaluation of a user-verification system for a smart gun, which is based on grip-pattern recognition. An existing pressure sensor consisting of an array of 44 × 44 piezoresistive elements is used to measure the grip pattern. An interface has been developed to acquire pressure images from the sensor. The values of the pixels in the pressure-pattern images are used as inputs for a verification algorithm, which is currently implemented in software on a PC. The verification algorithm is based on a likelihoodratio classifier for Gaussian probability densities. First results indicate that it is feasible to use grip-pattern recognition for biometric verification.

  18. Grip force and muscle activity differences due to glove type.

    PubMed

    Kovacs, Kimberly; Splittstoesser, Riley; Maronitis, Anthony; Marras, William S

    2002-01-01

    The purpose of this study was to investigate the effects of different types and sizes of gloves on external grip force and muscle activity. Twenty-one male and seven female volunteers served as subjects. Each subject performed two maximum voluntary grip contractions while wearing each of the 10 glove types. Results indicated significant differences in the effects of different glove types on the peak force, ratio of peak force to normalized flexor muscle EMG activity, and the ratio of peak force to coactivity.

  19. Two-handed grip on a mobile phone affords greater thumb motor performance, decreased variability, and a more extended thumb posture than a one-handed grip.

    PubMed

    Trudeau, Matthieu B; Asakawa, Deanna S; Jindrich, Devin L; Dennerlein, Jack T

    2016-01-01

    Holding a mobile computing device with two hands may affect thumb motor performance, joint postures, and device stability compared to holding the device and tapping the touchscreen with the thumb of the holding hand. We tested the hypotheses that holding a touchscreen mobile phone with two hands lead to increased thumb motor performance, different thumb postures, and decreased device movement relative to using one hand. Ten right-handed participants completed reciprocal thumb tapping tasks between emulated keys on a smartphone in either a one- (portrait) or two-handed (landscape) grip configuration. Effective index of performance measured from Fitts' Law was 9% greater (p < 0.001), movement time 7% faster (p < 0.001), and taps were 4% more precise (p < 0.016) for the two-handed grip. Tapping with a two-handed grip involved significantly different wrist and thumb postures than a one-handed grip. Variability of the computing device's movement was 36-63% lower for the two-handed grip compared to the one-handed grip condition (p < 0.001). The support for our hypotheses suggests that a two-handed grip results in increased performance and more extended wrist and thumb postures than a single-handed grip. Device designs that allow two-handed grips may afford increased performance relative to a one-handed grip.

  20. Body-scaled transitions in human grip configurations.

    PubMed

    Cesari, P; Newell, K M

    2000-10-01

    This article reports two experiments that were set up to examine the preferred human grip configuration used to displace cubes that varied in length (Lc), mass (Mc), and density (ML3). In particular, the authors sought to provide a more precise test of a dimensional relation between the object and the hand that had previously been shown to predict the grip configuration used to transport an object from one location to another. The experiments examined 2 grip transitions (from 3 digits to 4 digits and from 1 hand to 2 hands) within 2 sets of object conditions. In Experiment 1, cubes with a low density and a small increment in size (1 mm) were used, whereas in Experiment 2, cubes with 2 fixed sizes and small increments in mass were used. The results showed that the body-scaled equation K = logLc + (logMc/a + bMh + cLh), where Mh and Lh are the anthropometric measures of the hand mass and length and a, b, and c are empirical constants, is the body-scaled information that predicts the grip configurations used to displace objects.

  1. Soft shape-adaptive gripping device made from artificial muscle

    NASA Astrophysics Data System (ADS)

    Hamburg, E.; Vunder, V.; Johanson, U.; Kaasik, F.; Aabloo, A.

    2016-04-01

    We report on a multifunctional four-finger gripper for soft robotics, suitable for performing delicate manipulation tasks. The gripping device is comprised of separately driven gripping and lifting mechanisms, both made from a separate single piece of smart material - ionic capacitive laminate (ICL) also known as artificial muscle. Compared to other similar devices the relatively high force output of the ICL material allows one to construct a device able to grab and lift objects exceeding multiple times its own weight. Due to flexible design of ICL grips, the device is able to adapt the complex shapes of different objects and allows grasping single or multiple objects simultaneously without damage. The performance of the gripper is evaluated in two different configurations: a) the ultimate grasping strength of the gripping hand; and b) the maximum lifting force of the lifting actuator. The ICL is composed of three main layers: a porous membrane consisting of non-ionic polymer poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITFS), and a reinforcing layer of woven fiberglass cloth. Both sides of the membrane are coated with a carbonaceous electrode. The electrodes are additionally covered with thin gold layers, serving as current collectors. Device made of this material operates silently, requires low driving voltage (<3 V), and is suitable for performing tasks in open air environment.

  2. Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players.

    PubMed

    Wieczorek, Marta; Wiliński, Wojciech; Struzik, Artur; Rokita, Andrzej

    2015-11-22

    Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 - 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed.

  3. Grip strength at four years in relation to birth weight

    PubMed Central

    Dodds, R.; Macdonald-Wallis, C.; Kapasi, T.; Sayer, A. A.; Robinson, S.; Godfrey, K.; Cooper, C.; Harvey, N.; Inskip, H.

    2013-01-01

    Consistent positive relationships have been found between birth weight and grip strength in adults but evidence in children is limited. In a prospective general population birth cohort (Southampton Women’s Survey) grip strength and anthropometry (height and weight) were measured in 968 children at age 4 years. Mean (standard deviation (S.D.)) birth weight was 3.48 (0.52) kg. Birth weight, adjusted for sex and gestational age, was positively associated with grip strength (β = 0.22 kg/S.D. increase in adjusted birth weight; 95% CI 0.11, 0.34). The relationship was attenuated after adjustment for current height and weight such that it became non-significant (β = 0.03 kg/S.D. increase in adjusted birth weight; 95% CI −0.08, 0.14), suggesting that body size may be on the causal pathway. Early influences on muscle development appear to impact on grip strength in children as well as adults. PMID:24294479

  4. Get a Grip! A Middle School Engineering Challenge

    ERIC Educational Resources Information Center

    Olds, Suzanne A.; Harrell, Deborah A.; Valente, Michael E.

    2006-01-01

    Investigating the field of engineering offers the opportunity for interdisciplinary, hands-on, inquiry-based units that integrate real-world applications. However, many K-12 students are not exposed to engineering until they enter college. Get a Grip! is a problem-based unit that places middle school students in the role of engineers who are…

  5. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Cable clamps and grips. 18.40 Section 18.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and...

  6. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable clamps and grips. 18.40 Section 18.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and...

  7. Anticipatory modulation of precision grip force with variations in limb velocity of a curvilinear movement.

    PubMed

    Weeks, Douglas L; Sherwood, David E; Noteboom, J Timothy

    2002-03-01

    The authors examined the relationship between peak velocity of a discrete horizontal elbow flexion movement in which the hand path was curvilinear and premovement modulation of precision grip force. The velocity of the movements of 7 participants was varied from maximal velocity to a velocity that required several seconds to reach a target. An object instrumented with force transducers for the forefinger and thumb measured precision grip force. There was a positively accelerating quadratic relationship between grip force change before movement and peak velocity of the ensuing limb movement. On some low-velocity trials, premovement grip force modulation reflected a net decrease. In contrast, high-velocity trials were preceded by net increases in grip force. Using cluster analysis, the authors classified grip forces in low-velocity movements as an empirically distinct set of entities from grip forces in high-velocity movements. The cluster of high-value grip forces suggested an anticipatory strategy that allowed participants a large safety margin in grip force to avoid object slip on movement initiation. The cluster of low-value grip forces at movement initiation suggested a second anticipatory strategy in which participants changed grip force very little, perhaps to increase the ability of proprioceptors in the hand to sense force changes. Those findings suggest that modulation of grip force before initiation of movements in which the hand path is curvilinear may be governed by two distinct velocity-dependent anticipatory strategies.

  8. Rare gripping object in electrocution: Cadaveric spasm at its best.

    PubMed

    Chauhan, Mohit; Behera, C; Bodwal, Jatin; Dikshit, P C

    2017-01-01

    Cadaveric spasm causes instantaneous rigor without preceding post-mortem flaccidity. The precise pathophysiological basis of this phenomenon is still unknown. We report a case of accidental electrocution where the deceased was found dead with a metallic water supply pipe of a motor booster pump firmly gripped in his hand. In this report, we review the literature and consider the mechanisms that may cause this phenomenon.

  9. Grip control in children before, during, and after impulsive loading.

    PubMed

    Bleyenheuft, Yannick; Thonnard, Jean-Louis

    2010-01-01

    The manipulation of small objects requires continuous contributions from both predictive and reactive mechanisms. The authors aimed to study the development of predictive and reactive mechanisms used by children from 6 to 14 years of age to manage impulsive loading. The load of a handheld object was increased rapidly by the drop of a weight hung on the object. The drop was triggered either by the child (predictive condition) or by the examiner (reactive condition). Regardless of the condition, the control strategy was refined with age. Younger children were unable to adapt their grip force (GF) to the friction of their fingers, whereas the older children provided GF that was well adapted to their variable coefficient of friction, thereby producing a secure grip. This reflected either an inadequate amount of force or an inability to integrate cutaneous information from the fingers in younger children. Additionally, a modulation with age for both predictive and reactive mechanisms was observed. All together, the better predictive abilities and the more secure grip exhibited by older children allow decreased slipping and improved performance in an impulsive loading task.

  10. Effects of hyperthyroidism on hand grip strength and function.

    PubMed

    Erkol İnal, Esra; Çarlı, Alparslan Bayram; Çanak, Sultan; Aksu, Oğuzhan; Köroğlu, Banu Kale; Savaş, Serpil

    2015-01-01

    Hyperthyroidism is a pathologic condition in which the body is exposed to excessive amounts of circulating thyroid hormones. Skeletal muscle is one of the major target organs of thyroid hormones. We evaluated hand grip strength and function in patients with overt hyperthyroidism. Fifty-one patients newly diagnosed with hyperthyroidism and 44 healthy controls participated in this study. Age, height, weight, and dominant hand of all participants were recorded. The diagnosis of hyperthyroidism was confirmed by clinical examination and laboratory tests. Hand grip strength was tested at the dominant hand with a Jamar hand dynamometer. The grooved pegboard test (PGT) was used to evaluate hand dexterity. The Duruöz Hand Index (DHI) was used to assess hand function. No significant differences were found in terms of clinical and demographic findings between the patients with hyperthyroidism and healthy controls (p > 0.05). Significant differences were found between the patients with hyperthyroidism and healthy controls regarding PGT and DHI scores (p < 0.05). Hyperthyroidism seemed to affect hand dexterity and function more than hand grip strength and seemed to be associated with reduced physical function more than muscle strength. This may also indicate that patients with hyperthyroidism should be evaluated by multidisplinary modalities.

  11. An investigation of the cortical control of forepaw gripping after cervical hemisection injuries in rats.

    PubMed

    Strong, Melissa K; Blanco, Jennifer E; Anderson, Kim D; Lewandowski, Gail; Lewandoski, Gail; Steward, Oswald

    2009-05-01

    Previous studies in mice have demonstrated that forepaw gripping ability, as measured by a grip strength meter (GSM), is dependent on the contralateral sensorimotor cortex, but this dependency changes after hemisection injury at cervical level 4 (C4). Initially, the mouse fails to grip with the forepaw ipsilateral to the hemisection but gripping recovers. Additionally, a mouse's gripping by the contralateral paw becomes independent of the sensorimotor cortex, indicating a reorganization of cortical control of gripping function (Blanco, J.E., Anderson, K.D., Steward, O. 2007. Recovery of forepaw gripping ability and reorganization of cortical motor control following cervical spinal cord injuries in mice. Exp. Neurol. 203, 333-348.). Here we explore whether a similar reorganization occurs after cervical hemisection injuries in rats. We show that as in mice, unilateral lesions of the sensorimotor cortex impair rats' griping by the contralateral paw. We also confirm from previous studies that cervical hemisections impair rats' griping by the ipsilateral paw. In contrast to mice, however there is minimal recovery of gripping after complete lateral hemisections and secondary lesions of the sensorimotor cortex continue to impair rats' gripping by the contralateral paw. Thus, forelimb gripping ability as measured by the GSM is dependent on the contralateral sensorimotor cortex in rats even after a cervical hemisection.

  12. Capuchin monkey (Cebus apella) grips for the use of stone tools.

    PubMed

    Westergaard, G C; Suomi, S J

    1997-05-01

    This research examined capuchin monkey (Cebus apella) grips for the use of throwing, nut-cracking and cutting tools. We provided subjects with stones and apparatus that accommodated the use of stones as tools. Our subjects exhibited five grips, two of which the animals used when force was the primary consideration (power grips) and three of which the animals used when accuracy of sensory judgment and instrumentation was required (precision grips). We believe that the range of contexts in which capuchins use stone tools, combined with the ability of capuchins to employ both power and precision grips as part of their tool repertoire, indicate that Cebus apella can be used to identify grips that facilitated hominid lithic technology.

  13. A review of compression glove modifications to enhance functional grip: a case series.

    PubMed

    Dewey, William Scott; Richard, Reg L; Hedman, Travis L; Chapman, Ted T; Quick, Charles D; Holcomb, John B; Wolf, Steve E

    2007-01-01

    A common complaint among patients with burns is their inability to grasp items while wearing compression gloves. Recent technological innovations permit the addition of grip-enhancing material to garment fabric. The purpose of this case series was to describe the course of development of compression gloves with enhanced grip modifications. Five different types of grip modifications were made during a period of 18 months. Five subjects who were prescribed compression gloves tested each type of glove. The gloves were fabricated with grip-enhancing material on the palmar surface in five ways: 1) rectangular rubber tabs; 2) honeycomb pattern silicone; 3) wave-like pattern silicone; 4) line pattern silicone beads; 5) line pattern silicone beads embedded into the fabric. Each glove was evaluated on a three-point Likert scale (0 = poor, 1 = moderate, 2 = good) for grip-enhancing qualities and durability. All five subjects reported similar experiences with each glove type: 1) the rectangular rubber tabs demonstrated poor grip and moderate durability; 2) the honeycomb pattern provided good grip but poor durability; 3) the wave pattern had good grip and moderate durability; 4) the silicone beads adhered to the fabric had moderate grip but poor durability; 5) the silicone beads embedded into the fabric had moderate grip and good durability. The wave pattern provided the best gripping capability and silicone embedded into the fabric demonstrated the best durability. A wave-like pattern silicone material embedded into the fabric seems to provide the best combination of grip and durability to enhance activities of daily living performance.

  14. Control of Precision Grip Force in Lifting and Holding of Low-Mass Objects

    PubMed Central

    Kimura, Daisuke; Kadota, Koji; Ito, Taro

    2015-01-01

    Few studies have investigated the control of grip force when manipulating an object with an extremely small mass using a precision grip, although some related information has been provided by studies conducted in an unusual microgravity environment. Grip-load force coordination was examined while healthy adults (N = 17) held a moveable instrumented apparatus with its mass changed between 6 g and 200 g in 14 steps, with its grip surface set as either sandpaper or rayon. Additional measurements of grip-force-dependent finger-surface contact area and finger skin indentation, as well as a test of weight discrimination, were also performed. For each surface condition, the static grip force was modulated in parallel with load force while holding the object of a mass above 30 g. For objects with mass smaller than 30 g, on the other hand, the parallel relationship was changed, resulting in a progressive increase in grip-to-load force (GF/LF) ratio. The rayon had a higher GF/LF force ratio across all mass levels. The proportion of safety margin in the static grip force and normalized moment-to-moment variability of the static grip force were also elevated towards the lower end of the object mass for both surfaces. These findings indicate that the strategy of grip force control for holding objects with an extremely small mass differs from that with a mass above 30 g. The data for the contact area, skin indentation, and weight discrimination suggest that a decreased level of cutaneous feedback signals from the finger pads could have played some role in a cost function in efficient grip force control with low-mass objects. The elevated grip force variability associated with signal-dependent and internal noises, and anticipated inertial force on the held object due to acceleration of the arm and hand, could also have contributed to the cost function. PMID:26376484

  15. Control of Precision Grip Force in Lifting and Holding of Low-Mass Objects.

    PubMed

    Hiramatsu, Yuichi; Kimura, Daisuke; Kadota, Koji; Ito, Taro; Kinoshita, Hiroshi

    2015-01-01

    Few studies have investigated the control of grip force when manipulating an object with an extremely small mass using a precision grip, although some related information has been provided by studies conducted in an unusual microgravity environment. Grip-load force coordination was examined while healthy adults (N = 17) held a moveable instrumented apparatus with its mass changed between 6 g and 200 g in 14 steps, with its grip surface set as either sandpaper or rayon. Additional measurements of grip-force-dependent finger-surface contact area and finger skin indentation, as well as a test of weight discrimination, were also performed. For each surface condition, the static grip force was modulated in parallel with load force while holding the object of a mass above 30 g. For objects with mass smaller than 30 g, on the other hand, the parallel relationship was changed, resulting in a progressive increase in grip-to-load force (GF/LF) ratio. The rayon had a higher GF/LF force ratio across all mass levels. The proportion of safety margin in the static grip force and normalized moment-to-moment variability of the static grip force were also elevated towards the lower end of the object mass for both surfaces. These findings indicate that the strategy of grip force control for holding objects with an extremely small mass differs from that with a mass above 30 g. The data for the contact area, skin indentation, and weight discrimination suggest that a decreased level of cutaneous feedback signals from the finger pads could have played some role in a cost function in efficient grip force control with low-mass objects. The elevated grip force variability associated with signal-dependent and internal noises, and anticipated inertial force on the held object due to acceleration of the arm and hand, could also have contributed to the cost function.

  16. Finger pad friction and its role in grip and touch.

    PubMed

    Adams, Michael J; Johnson, Simon A; Lefèvre, Philippe; Lévesque, Vincent; Hayward, Vincent; André, Thibaut; Thonnard, Jean-Louis

    2013-03-06

    Many aspects of both grip function and tactile perception depend on complex frictional interactions occurring in the contact zone of the finger pad, which is the subject of the current review. While it is well established that friction plays a crucial role in grip function, its exact contribution for discriminatory touch involving the sliding of a finger pad is more elusive. For texture discrimination, it is clear that vibrotaction plays an important role in the discriminatory mechanisms. Among other factors, friction impacts the nature of the vibrations generated by the relative movement of the fingertip skin against a probed object. Friction also has a major influence on the perceived tactile pleasantness of a surface. The contact mechanics of a finger pad is governed by the fingerprint ridges and the sweat that is exuded from pores located on these ridges. Counterintuitively, the coefficient of friction can increase by an order of magnitude in a period of tens of seconds when in contact with an impermeably smooth surface, such as glass. In contrast, the value will decrease for a porous surface, such as paper. The increase in friction is attributed to an occlusion mechanism and can be described by first-order kinetics. Surprisingly, the sensitivity of the coefficient of friction to the normal load and sliding velocity is comparatively of second order, yet these dependencies provide the main basis of theoretical models which, to-date, largely ignore the time evolution of the frictional dynamics. One well-known effect on taction is the possibility of inducing stick-slip if the friction decreases with increasing sliding velocity. Moreover, the initial slip of a finger pad occurs by the propagation of an annulus of failure from the perimeter of the contact zone and this phenomenon could be important in tactile perception and grip function.

  17. Finger pad friction and its role in grip and touch

    PubMed Central

    Adams, Michael J.; Johnson, Simon A.; Lefèvre, Philippe; Lévesque, Vincent; Hayward, Vincent; André, Thibaut; Thonnard, Jean-Louis

    2013-01-01

    Many aspects of both grip function and tactile perception depend on complex frictional interactions occurring in the contact zone of the finger pad, which is the subject of the current review. While it is well established that friction plays a crucial role in grip function, its exact contribution for discriminatory touch involving the sliding of a finger pad is more elusive. For texture discrimination, it is clear that vibrotaction plays an important role in the discriminatory mechanisms. Among other factors, friction impacts the nature of the vibrations generated by the relative movement of the fingertip skin against a probed object. Friction also has a major influence on the perceived tactile pleasantness of a surface. The contact mechanics of a finger pad is governed by the fingerprint ridges and the sweat that is exuded from pores located on these ridges. Counterintuitively, the coefficient of friction can increase by an order of magnitude in a period of tens of seconds when in contact with an impermeably smooth surface, such as glass. In contrast, the value will decrease for a porous surface, such as paper. The increase in friction is attributed to an occlusion mechanism and can be described by first-order kinetics. Surprisingly, the sensitivity of the coefficient of friction to the normal load and sliding velocity is comparatively of second order, yet these dependencies provide the main basis of theoretical models which, to-date, largely ignore the time evolution of the frictional dynamics. One well-known effect on taction is the possibility of inducing stick–slip if the friction decreases with increasing sliding velocity. Moreover, the initial slip of a finger pad occurs by the propagation of an annulus of failure from the perimeter of the contact zone and this phenomenon could be important in tactile perception and grip function. PMID:23256185

  18. Biomechanical analysis of flexor digitorum profundus and superficialis in grip-strength generation.

    PubMed

    Kaufmann, Robert A; Kozin, Scott H; Mirarchi, Adam; Holland, Burt; Porter, Scott

    2007-09-01

    Grip strength is generated through extrinsic flexor tendon and intrinsic muscle actuation. In the study reported here, we analyzed the grip-generating properties of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons during grip-strength generation. In vivo gripping was reproduced in 11 cadaveric forearms through pneumatic tensioning of flexor tendons. A Jamar dynamometer (TEC, Clifton, NJ) was positioned in the hand at varying degrees of angulation measured between the Jamar compression axis and the second metacarpal. Maximum gripping strength during isolated FDP and FDS tensioning generated maximum compressive forces at different angles (P < .0001). The isolated FDP showed continued increased grip strength with larger angles and was most effective when the dynamometer handle was in contact with the distal phalanx. The isolated FDS was most effective at smaller angles when the handle made contact with the middle phalanx. The isolated FDS shows an initial increase in grip strength as the contact point moves toward the middle phalanx (P < .01) and then a tendency for grip strength to decline as the contact point moves over the distal phalanx (P < .01). The FDP and FDS tendons demonstrate unique abilities to generate compression on a dynamometer. This knowledge is important to consider when evaluating grip strength in patients who have injured the extrinsic finger flexors.

  19. Precision-grip force changes in the anatomical and prosthetic limb during predictable load increases.

    PubMed

    Weeks, D L; Wallace, S A; Noteboom, J T

    2000-06-01

    This study examined precision-grip force applied to an instrumented test object held aloft while the weight of the object was predictably varied by transporting and placing loads (50, 100, or 200 g) atop the test object. Transport of the loads was performed either by the subject or the experimenter. Grip force was examined in four non-amputee control subjects and in the anatomical and prosthetic hand of a subject with a prosthetic device. As subjects transported the load, anticipatory grip-force changes occurred in the anatomical hands and prosthetic hand, which were scaled in relation to the load. When the experimenter transported the load to the anatomical hands of control subjects or the prosthetic user, anticipatory increases in grip force occurred that also were scaled in relation to load. However, when the experimenter transported the load to the prosthetic hand, anticipatory grip-force adjustments were absent. During the phase in which the load was being assumed by the postural hand, grip forces in the anatomical hands and prosthetic hand were further scaled to load demands. Ability to adapt grip force in the prosthetic hand during this phase suggested that the subject was utilizing sensory information from the residual limb to adjust grip force. Thus, while anticipatory changes precede the process of adaptation to load changes, actual sensory consequences resulting from added weight remain necessary to fully adapt grip force to load demands, even for the prosthetic user.

  20. Vitamin D status is associated with grip strength in centenarians.

    PubMed

    Haslam, Alyson; Johnson, Mary Ann; Hausman, Dorothy B; Cress, M Elaine; Houston, Denise K; Davey, Adam; Poon, Leonard W

    2014-01-01

    Low serum concentrations of 25-hydroxyvitamin D (25(OH)D) have been associated with poor physical function in older adults, but few, if any, studies have examined this relationship in the very old. Therefore, the purpose of this study is to examine this relationship in the very old. Serum 25(OH)D concentrations were obtained from 194 centenarians and near centenarians (98 years and older). The associations between 25(OH)D concentrations and measures of physical function were evaluated with unadjusted and adjusted regression models. We found that 35% of centenarians had 25(OH)D concentrations less than 50 nmol/L. Adjusted mean grip strength was lower for centenarians with 25(OH)D concentrations less than 75 nmol/L than for centenarians with higher concentrations (P<0.05). However, there were no differences in the Georgia Centenarian Study (GCS) Composite Scale, a global measure of physical function, between those with higher and lower 25(OH)D concentrations. We conclude that low 25(OH)D concentrations are associated with poor grip strength, but not GCS Composite Scale, in the very old. Considering the high burden of poor physical function in older adults, understanding the relationship between vitamin D and different measures of physical function, including strength, becomes increasingly important.

  1. Precision Grip Control while Walking Down a Stair Step

    PubMed Central

    Ebner-Karestinos, Daniela; Thonnard, Jean-Louis; Bleyenheuft, Yannick

    2016-01-01

    The aim of this study was to determine whether the internal model regulating grip force (GF)/load force (LF) coordination during a brisk load increase is preserved when the lower extremities produce a perturbation during a single step-down task. We observed the coordination of the vertical ground reaction force (vGRF), GF and LF while holding a handheld object during a single step-down task. The 3 forces (vGRF, GF and LF) decreased during the start of the task. While the subject was descending, LF and GF became dissociated from vGRF and increased in value, probably to anticipate the first foot contact. Coordination of LF and GF was maintained until the maximal vGRF (knee extension). LF peaked in the same time window as vGRF, whereas GF peaked about 70 ms later. This desynchronization, which was previously observed in direct load increase on a handheld object, was interpreted to be a predictive action to ensure the smooth management of the brisk increase in load induced by the lower extremities. Incidentally, in this group, kinematic and dynamic differences were observed between men and women, which may highlight a gender-specific strategy to perform the step-down task. In conclusion, these results suggest that the internal model of precision grip is able to integrate a brisk load change, whatever its origin, and regulate the forces to provide an ideal GF to dampen a brisk load increase and secure the object. PMID:27802343

  2. Grip pressure measurements during activities of daily life

    NASA Astrophysics Data System (ADS)

    Sanford, Joe; Young, Carolyn; Popa, Dan; Bugnariu, Nicoleta; Patterson, Rita

    2014-06-01

    Research has expanded human-machine communication methods past direct programming and standard hand- held joystick control. Individual force sensors have been used as a simple means of providing environmental information to a robot and research has shown that more advanced sensitive skins can be viable input devices. These touch sensitive surfaces allow for additional modes of interaction between machines in open, undefined environments. These interactions include object detection for navigation and safety but can also be used for recognition of users command gestures by their machine partner. Key to successful implementation of these gestures is the understanding of varied strategies used for communication and interaction and the development of performance limits. Data of dominant hand grip forces was collected using a Tekscan Grip VersaTek Pressure Measurement System during opening of a door. Analysis of data from 10 male and female subjects is presented. The results of qualitative and quantitative analysis of these data show variability in hand configurations between users. Average data over the cohort is reported. These data will be used in future work to provide human metrology constraints and limits for use in simulation and design of new, physical human-robot interaction systems.

  3. Comparison of Infant Car Seat grip orientations and lift strategies.

    PubMed

    Clamann, Michael; Zhu, Biwen; Beaver, Leah; Taylor, Kinley; Kaber, David

    2012-07-01

    The rear-facing Infant Car Seat (ICS) is designed to meet federal requirements for transporting children less than 1 year old. Typical use includes transfer in and out of a vehicle, which is shown to be a difficult lift. Despite the frequency of this lift, manufacturers provide little guidance for users. Review of relevant literature suggested an ICS featuring an angled handle, promoting a neutral wrist posture, would increase grip stability and decrease lifting effort. Popular press suggested a foot-in-car stance for the ICS lift would do the same. An experiment was conducted in which wrist deviations from neutral posture were recorded along with lifting muscle activation levels (multiple flexor muscles and biceps brachii) and overall perceived exertion for straight versus a new bent handle design and conventional stance versus foot-in-car. Foot position was examined to test the recommendations in the popular press. Surprisingly, wrist deviation was not significantly affected by the new bent handle design (due to compensatory behavior with the straight handle) but was related to foot placement (p=0.04). Results revealed the bent handle to significantly reduce flexor activation compared with the straight handle (p=0.0003); however, the level of biceps activation increased. Biceps activation also significantly increased for foot-in-car stance (p=0.035) but not flexor activation. In general, the bent handle enabled the user to lift the ICS with a steadier grip and less effort.

  4. Influence of central set on anticipatory and triggered grip-force adjustments

    NASA Technical Reports Server (NTRS)

    Winstein, C. J.; Horak, F. B.; Fisher, B. E.; Peterson, B. W. (Principal Investigator)

    2000-01-01

    The effects of predictability of load magnitude on anticipatory and triggered grip-force adjustments were studied as nine normal subjects used a precision grip to lift, hold, and replace an instrumented test object. Experience with a predictable stimulus has been shown to enhance magnitude scaling of triggered postural responses to different amplitudes of perturbations. However, this phenomenon, known as a central-set effect, has not been tested systematically for grip-force responses in the hand. In our study, predictability was manipulated by applying load perturbations of different magnitudes to the test object under conditions in which the upcoming load magnitude was presented repeatedly or under conditions in which the load magnitudes were presented randomly, each with two different pre-load grip conditions (unconstrained and constrained). In constrained conditions, initial grip forces were maintained near the minimum level necessary to prevent pre-loaded object slippage, while in unconstrained conditions, no initial grip force restrictions were imposed. The effect of predictable (blocked) and unpredictable (random) load presentations on scaling of anticipatory and triggered grip responses was tested by comparing the slopes of linear regressions between the imposed load and grip response magnitude. Anticipatory and triggered grip force responses were scaled to load magnitude in all conditions. However, regardless of pre-load grip force constraint, the gains (slopes) of grip responses relative to load magnitudes were greater when the magnitude of the upcoming load was predictable than when the load increase was unpredictable. In addition, a central-set effect was evidenced by the fewer number of drop trials in the predictable relative to unpredictable load conditions. Pre-load grip forces showed the greatest set effects. However, grip responses showed larger set effects, based on prediction, when pre-load grip force was constrained to lower levels. These

  5. Age-Related and Sex-Related Differences in Hand and Pinch Grip Strength in Adults

    ERIC Educational Resources Information Center

    Puh, Urska

    2010-01-01

    The purpose of the study was to quantify age-related changes in hand grip strength and three types of pinch grip strength (key pinch, tip pinch, and palmar pinch) among male and female participants. The study included 199 healthy participants (100 females, 99 males) aged 20-79 years, who were divided into four age groups. The Baseline Hydraulic…

  6. The Geostationary Remote Infrared Pollution Sounder (GRIPS): measurement of the carbon gases from space

    NASA Astrophysics Data System (ADS)

    Schoeberl, M.; Dickerson, R.; Marshall, B. T.; McHugh, M.; Fish, C.; Bloom, H.

    2013-09-01

    Climate change and air quality are the most pressing environmental issues of the 21st century. Despite decades of research, the sources and sinks of key greenhouse gases remain highly uncertain [IPCC1] making quantitative predictions of atmospheric composition and their impacts. The Geostationary Remote Infrared Pollution Sounder (GRIPS) is a multi-purpose instrument designed to reduce uncertainty associated with atmospheric radiative forcing. GRIPS will measure will measure greenhouse gases and aerosols - two of the most important elements in the earth's radiation budget. GRIPS will observe carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), - the carbon gases, nitrous oxide (N2O), water vapor and aerosols with unprecedented precision through the atmosphere. The GRIPS instrument uses gas filter correlation radiometry (GFCR) to detect reflected and thermal IR radiation to detect the gases and the reflected solar radiation in the visible and short-wave infrared bands for aerosols. GRIPS is designed to have sensitivity down to the Earth's surface at ~2-8km nadir resolution. GRIPS can resolve CO2, CO, and CH4 anomalies in the planetary boundary layer and the free troposphere to quantify lofting, diurnal variations and longrange transport. With repeated measurements throughout the day GRIPS can maximize the number of cloud free measurements determining biogenic and anthropogenic sources, sinks, and fluxes. GRIPS is highly complementary to the Orbiting Carbon Observatory, OCO-2, the geostationary Tropospheric Emissions: Monitoring of Pollution (TEMPO) and Advanced Baseline Imager (ABI) and other existing and planned missions.

  7. Quantitative grip strength assessment as a means of evaluating muscle relaxation in mice.

    PubMed

    Nevins, M E; Nash, S A; Beardsley, P M

    1993-01-01

    The effects of various centrally acting drugs and some peripherally acting agents on the forelimb grip strength of CD-1 mice were explored. Forelimb grip strength was assessed by use of a strain gauge to measure the lateral pull force, in grams, exerted by mice as an index of muscle relaxation. The muscle relaxants, diazepam, midazolam, baclofen, methocarbamol, dantrolene sodium and the neuromuscular blocking agents, succinylcholine and pancuronium bromide, dose-dependently reduced forelimb grip strength. 2-Amino-7-phosphonoheptanoic acid (AP7), which has also been shown to have muscle relaxant effects, also reduced grip strength. Pentobarbital, ethanol, phencyclidine, ketamine and chlorpromazine reduced grip strength at doses which produced behavioral impairments. Lithium chloride, a toxic compound used to induce taste aversions, and clonidine, at doses which affect blood pressure, body temperature and locomotor activity, did not affect grip strength. In addition, stimulant doses of amphetamine and caffeine, but not of morphine, increased grip strength in a dose-dependent manner. These results extend previous findings and suggest that this forelimb grip strength procedure may be a useful screening test for the identification of the potential muscle relaxant properties of drugs.

  8. The Effect of Handedness on Grip Strength in Older Adults with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Oppewal, Alyt; Hilgenkamp, Thessa I. M.; van Wijck, Ruud; Evenhuis, Heleen M.

    2013-01-01

    Grip strength is an important predictor of several health outcomes in the general older population. Grip strength assessment is feasible and reliable in older adults with intellectual disabilities (ID), which makes it a valuable measurement for application in this population. The purpose of this study was to investigate the effect of handedness on…

  9. Grip force and force sharing in two different manipulation tasks with bottles.

    PubMed

    Cepriá-Bernal, Javier; Pérez-González, Antonio; Mora, Marta C; Sancho-Bru, Joaquín L

    2016-09-23

    Grip force and force sharing during two activities of daily living were analysed experimentally in 10 right-handed subjects. Four different bottles, filled to two different levels, were manipulated for two tasks: transporting and pouring. Each test subject's hand was instrumented with eight thin wearable force sensors. The grip force and force sharing were significantly different for each bottle model. Increasing the filling level resulted in an increase in grip force, but the ratio of grip force to load force was higher for lighter loads. The task influenced the force sharing but not the mean grip force. The contributions of the thumb and ring finger were higher in the pouring task, whereas the contributions of the palm and the index finger were higher in the transport task. Mean force sharing among fingers was 30% for index, 29% for middle, 22% for ring and 19% for little finger. Practitioner Summary: We analysed grip force and force sharing in two manipulation tasks with bottles: transporting and pouring. The objective was to understand the effects of the bottle features, filling level and task on the contribution of different areas of the hand to the grip force. Force sharing was different for each task and the bottles features affected to both grip force and force sharing.

  10. I forgot when I lost my grip-strong associations between cognition and grip strength in level of performance and change across time in relation to impending death.

    PubMed

    Praetorius Björk, Marcus; Johansson, Boo; Hassing, Linda B

    2016-02-01

    An association between level of cognitive function and grip strength is well established, whereas evidence for longitudinal associations of change in the 2 functions is still unclear. We examined associations between cognition and grip strength in levels of performance and in longitudinal change in late life in a population-based sample, aged ≥80 years at baseline, followed until death. The sample consisted of 449 nondemented individuals drawn from the OCTO-Twin Study. A test battery assessing 6 cognitive domains and grip strength was administered at 5 occasions with measurements intervals of 2 years. We fitted time to death bivariate growth curve models, adjusted for age, education, and sex which resulted in associations between grip strength and cognition in both levels of performance (across all cognitive domains) and rates of change (in 4 of 6 domains). These results show that cognition and grip strength change conjointly in later life and that the association between cognition and grip strength is stronger before death than earlier in life.

  11. Decoding gripping force based on local field potentials recorded from subthalamic nucleus in humans.

    PubMed

    Tan, Huiling; Pogosyan, Alek; Ashkan, Keyoumars; Green, Alexander L; Aziz, Tipu; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Brown, Peter

    2016-11-18

    The basal ganglia are known to be involved in the planning, execution and control of gripping force and movement vigour. Here we aim to define the nature of the basal ganglia control signal for force and to decode gripping force based on local field potential (LFP) activities recorded from the subthalamic nucleus (STN) in patients with deep brain stimulation (DBS) electrodes. We found that STN LFP activities in the gamma (55-90 Hz) and beta (13-30m Hz) bands were most informative about gripping force, and that a first order dynamic linear model with these STN LFP features as inputs can be used to decode the temporal profile of gripping force. Our results enhance the understanding of how the basal ganglia control gripping force, and also suggest that deep brain LFPs could potentially be used to decode movement parameters related to force and movement vigour for the development of advanced human-machine interfaces.

  12. Effects of carpal tunnel syndrome on dexterous manipulation are grip type-dependent.

    PubMed

    Zhang, Wei; Johnston, Jamie A; Ross, Mark A; Sanniec, Kyle; Gleason, Elizabeth A; Dueck, Amylou C; Santello, Marco

    2013-01-01

    Carpal tunnel syndrome (CTS) impairs sensation of a subset of digits. Although the effects of CTS on manipulation performed with CTS-affected digits have been studied using precision grip tasks, the extent to which CTS affects multi-digit force coordination has only recently been studied. Whole-hand manipulation studies have shown that CTS patients retain the ability to modulate multi-digit forces to object mass, mass distribution, and texture. However, CTS results in sensorimotor deficits relative to healthy controls, including significantly larger grip force and lower ability to balance the torques generated by the digits. Here we investigated the effects of CTS on multi-digit force modulation to object weight when manipulating an object with a variable number of fingers. We hypothesized that CTS patients would be able to modulate digit forces to object weight. However, as different grip types involve the exclusive use of CTS-affected digits ('uniform' grips) or a combination of CTS-affected and non-affected digits ('mixed' grips), we addressed the question of whether 'mixed' grips would reduce or worsen CTS-induced force coordination deficits. The former scenario would be due to adding digits with intact tactile feedback, whereas the latter scenario might occur due to a potentially greater challenge for the central nervous system of integrating 'noisy' and intact tactile feedback. CTS patients learned multi-digit force modulation to object weight regardless of grip type. Although controls exerted the same total grip force across all grip types, patients exerted significantly larger grip force than controls but only for manipulations with four and five digits. Importantly, this effect was due to CTS patients' inability to change the finger force distribution when adding the ring and little fingers. These findings suggest that CTS primarily challenges sensorimotor integration processes for dexterous manipulation underlying the coordination of CTS-affected and non

  13. Effects of Carpal Tunnel Syndrome on Dexterous Manipulation Are Grip Type-Dependent

    PubMed Central

    Zhang, Wei; Johnston, Jamie A.; Ross, Mark A.; Sanniec, Kyle; Gleason, Elizabeth A.; Dueck, Amylou C.; Santello, Marco

    2013-01-01

    Carpal tunnel syndrome (CTS) impairs sensation of a subset of digits. Although the effects of CTS on manipulation performed with CTS-affected digits have been studied using precision grip tasks, the extent to which CTS affects multi-digit force coordination has only recently been studied. Whole-hand manipulation studies have shown that CTS patients retain the ability to modulate multi-digit forces to object mass, mass distribution, and texture. However, CTS results in sensorimotor deficits relative to healthy controls, including significantly larger grip force and lower ability to balance the torques generated by the digits. Here we investigated the effects of CTS on multi-digit force modulation to object weight when manipulating an object with a variable number of fingers. We hypothesized that CTS patients would be able to modulate digit forces to object weight. However, as different grip types involve the exclusive use of CTS-affected digits (‘uniform’ grips) or a combination of CTS-affected and non-affected digits (‘mixed’ grips), we addressed the question of whether ‘mixed’ grips would reduce or worsen CTS-induced force coordination deficits. The former scenario would be due to adding digits with intact tactile feedback, whereas the latter scenario might occur due to a potentially greater challenge for the central nervous system of integrating ‘noisy’ and intact tactile feedback. CTS patients learned multi-digit force modulation to object weight regardless of grip type. Although controls exerted the same total grip force across all grip types, patients exerted significantly larger grip force than controls but only for manipulations with four and five digits. Importantly, this effect was due to CTS patients’ inability to change the finger force distribution when adding the ring and little fingers. These findings suggest that CTS primarily challenges sensorimotor integration processes for dexterous manipulation underlying the coordination of CTS

  14. Butterfly survival on an isolated island by improved grip.

    PubMed

    Duplouy, Anne; Hanski, Ilkka

    2013-04-23

    On small isolated islands, natural selection is expected to reduce the dispersal capacity of organisms, as short distances do not require a high rate of dispersal, which might lead to accidental emigration from the population. In addition, individuals foregoing the high cost of maintaining flight capacity may instead allocate resources to other functions. However, in butterflies and many other insects, flight is necessary not only for dispersal but also for most other activities. A weakly flying individual would probably do worse and have an elevated rather than reduced probability of accidental emigration. Here, we report results consistent with the hypothesis that a butterfly population on an isolated island, instead of having lost its flight capacity, has evolved better grip to resist the force of wind and to avoid being blown off the island. Our study suggests that local adaptation has occurred in this population in spite of its very small size (Ne ∼ 100), complete isolation, low genetic variation and high genetic load.

  15. Revised normative values for grip strength with the Jamar dynamometer.

    PubMed

    Peters, Martine J H; van Nes, Sonja I; Vanhoutte, Els K; Bakkers, Mayienne; van Doorn, Pieter A; Merkies, Ingemar S J; Faber, Catharina G

    2011-03-01

    The Jamar dynamometer has been widely used in various chronic illnesses and has demonstrated its strength as a potential prognostic indicator. Various stratified normative values have been published using different methodologies, leading to conflicting results. No study used statistical techniques considering the non-Gaussian distribution of the obtained grip strength (GS) values. Jamar GS was assessed in 720 healthy participants, subdivided into seven age decade groups consisting of at least 50 men and 50 women each. Normative values (median and fifth values) were calculated using quantile regressions with restricted cubic spline functions on age. Possible confounding personal factors (hand dominance, length, weight, hobby, and job categorization) were examined. Clinically applicable revised normative values for the Jamar dynamometer, stratified for age and gender, are presented. Hand dominance had no influence. Other personal factors only minimally influenced final values. This study provides revised normative GS values for the Jamar dynamometer.

  16. NBL Pistol Grip Tool for Underwater Training of Astronauts

    NASA Technical Reports Server (NTRS)

    Liszka, Michael; Ashmore, Matthew; Behnke, Mark; Smith, Walter; Waterman, Tod

    2011-01-01

    A document discusses a lightweight, functional mockup of the Pistol Grip Tool for use during underwater astronaut training. Previous training tools have caused shoulder injuries. This new version is more than 50 percent lighter [in water, weight is 2.4 lb (=1.1 kg)], and can operate for a six-hour training session after 30 minutes of prep for submersion. Innovations in the design include the use of lightweight materials (aluminum and Delrin(Registered TradeMark)), creating a thinner housing, and the optimization of internal space with the removal of as much excess material as possible. This reduces tool weight and maximizes buoyancy. Another innovation for this tool is the application of a vacuum that seats the Orings in place and has shown to be reliable in allowing underwater usage for up to six hours.

  17. Tracking Decrement as a Result of Grip Holding Endurance.

    PubMed

    Bloswick, D S; Ellis, N C

    1974-01-01

    This study explores the feasibility of using the static strength and endurance relationships suggested by Rohmert in 1960 to predict pursuit tracking performance, Ten male subjects are tested on a pursuit rotor before and after being subjected to specific levels of loading on a grip holding device. The loading corresponded to specific levels of each subject's maximum endurance as determined from Rohmert's strength and endurance equation. The hypotheses are: (a) predetermined schedules of strength expenditure cause a systematic decrement in tracking efficiency; and (b) the process of recovering efficiency is dependent upon the expenditure schedules. Resulting data support these hypotheses, suggesting that tracking efficiency can be reliably predicted using some of the strength and endurance relationships postulated by Rohmert.

  18. The laboratory station for tyres grip testing on different surfaces

    NASA Astrophysics Data System (ADS)

    Kalinowski, K.; Grabowik, C.; Janik, W.; Ćwikła, G.; Skowera, M.

    2015-11-01

    The paper presents the conception of the device for tyre grip testing in the laboratory conditions. The main purpose is to provide a device working in confined spaces, which enables rapid changes of the tested samples of the road surfaces. Among the key assumptions the minimization of the device dimensions and the relative ease of transportation and mobility - the ability to quick assemble and disassemble were also assumed. The main components of the projected workstation includes: the replaceable platform for mounting samples of a road surface, the roller conveyor, the drive of the platform, the wheel mounting assembly and the axial force measuring system. At the design the station a morphological structure method has been used, particular elements have been optimized individually.

  19. Effects of kinesio tape compared with non-elastic tape on hand grip strength.

    PubMed

    Kim, Ji Young; Kim, Seong Yeol

    2016-05-01

    [Purpose] Many assumptions have been made about taping and several studies have considered tape application methods; however, the true effect of taping on muscle strength remains unclear. Most previous studies compared application techniques using Kinesio tape (KT), but studies that compared muscle strength using non-elastic tape (NT) are limited. Moreover, no studies have applied KT and NT in the same way to assess grip strength in normal subjects. The purpose of this study was to evaluate the immediate effect of application of two tapes with different elastic properties on maximal grip strength in healthy adults. [Subjects and Methods] Twenty healthy adults were divided into two groups (KT and NT). Maximal grip strength was measured with a dynamometer. Forearm extensor muscles of the dominant hand were then taped and subjects were immediately asked to perform hand grip movement with maximum strength in the same standardized manner. [Results] In the KT group, maximal grip strength was significantly increased compared to the initial value; however, in the NT group, there was no significant difference in maximal grip strength. [Conclusion] This study suggests that only Kinesio tape can increase maximal grip strength immediately after application on the extensor region of the forearm.

  20. Effects of kinesio tape compared with non-elastic tape on hand grip strength

    PubMed Central

    Kim, Ji Young; Kim, Seong Yeol

    2016-01-01

    [Purpose] Many assumptions have been made about taping and several studies have considered tape application methods; however, the true effect of taping on muscle strength remains unclear. Most previous studies compared application techniques using Kinesio tape (KT), but studies that compared muscle strength using non-elastic tape (NT) are limited. Moreover, no studies have applied KT and NT in the same way to assess grip strength in normal subjects. The purpose of this study was to evaluate the immediate effect of application of two tapes with different elastic properties on maximal grip strength in healthy adults. [Subjects and Methods] Twenty healthy adults were divided into two groups (KT and NT). Maximal grip strength was measured with a dynamometer. Forearm extensor muscles of the dominant hand were then taped and subjects were immediately asked to perform hand grip movement with maximum strength in the same standardized manner. [Results] In the KT group, maximal grip strength was significantly increased compared to the initial value; however, in the NT group, there was no significant difference in maximal grip strength. [Conclusion] This study suggests that only Kinesio tape can increase maximal grip strength immediately after application on the extensor region of the forearm. PMID:27313372

  1. Effect of hold depth and grip technique on maximal finger forces in rock climbing.

    PubMed

    Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

    2012-01-01

    The aim of this study was to understand how the commonly used climbing-specific grip techniques and hold depths influence the finger force capacities. Ten advanced climbers performed maximal voluntary force on four different hold depths (from 1 to 4 cm) and in two force directions (antero-posterior and vertical) using three grip techniques (slope, half crimp and full crimp). A specially designed platform instrumented with a 6-degrees-of-freedom (DoF) force/torque sensor was used to record force values. Results showed that the maximal vertical forces differed significantly according to the hold depth and the grip technique (ranged from 350.8 N to 575.7 N). The maximal vertical forces increased according to the hold depth but the form of this increase differed depending on grip technique. These results seemed to be more associated with finger-hold contact/interaction than with internal biomechanical factors. Similar results were revealed for antero-posterior forces (ranged from 69.9 N to 138.0 N) but, it was additionally noted that climbers have different hand-forearm posture strategies with slope and crimp grip techniques when applying antero-posterior forces. This point is important as it could influence the body position adopted during climbing according to the chosen grip technique. For trainers and designers, a polynomial regression model was proposed in order to predict the mean maximal force based on hold depth and adopted grip technique.

  2. Measurement of Hand/Handrim Grip Forces in Two Different One Arm Drive Wheelchairs

    PubMed Central

    2014-01-01

    Purpose. The aim of this study was to explore the total and regional grip forces in the hand when propelling two different manual one arm drive wheelchairs: the Neater Uni-wheelchair (NUW) and a foot steered Action3 wheelchair. Methods. 17 nondisabled users were randomly assigned to each wheelchair to drive around an indoor obstacle course. The Grip, a multiple sensor system taking continuous measurement of handgrip force, was attached to the propelling hand. Total grip force in each region of the hand and total grip force across the whole hand were calculated per user per wheelchair. Results. The Action3 with foot steering only generated significantly greater total grip force in straight running compared to the NUW and also in the fingers and thumb in straight running. Conclusions. The results suggest that the Action3 with foot steering generated greater grip forces which may infer a greater potential for repetitive strain injury in the upper limb. Further work is required to explore whether the difference in grip force is of clinical significance in a disabled population. PMID:25045684

  3. The effects of acute cortical somatosensory deafferentation on grip force control

    PubMed Central

    Richardson, Andrew G.; Attiah, Mark A.; Berman, Jeffrey I.; Chen, H. Isaac; Liu, Xilin; Zhang, Milin; Van der Spiegel, Jan; Lucas, Timothy H.

    2015-01-01

    Grip force control involves mechanisms to adjust to unpredictable and predictable changes in loads during manual manipulation. Somatosensory feedback is critical not just to reactive, feedback control but also to updating the internal representations needed for proactive, feedforward control. The role of primary somatosensory cortex (S1) in these control strategies is not well established. Here we investigated grip force control in a rare case of acute central deafferentation following resection of S1. The subject had complete loss of somatosensation in the right arm without any deficit in muscle strength or reflexes. In the first task, the subject was asked to maintain a constant grip force with and without visual feedback. The subject was able to attain the target force with visual feedback but not maintain that force for more than a few seconds after visual feedback was removed. In the second task, the subject was asked to grip and move an instrumented object. The induced acceleration-dependent loads were countered by adjustments in grip force. Both amplitude and timing of the grip force modulation were not affected by deafferentation. The dissociation of these effects demonstrates the differential contribution of S1 to the mechanisms of grip force control. PMID:26587914

  4. Using Hand Grip Force as a Correlate of Longitudinal Acceleration Comfort for Rapid Transit Trains.

    PubMed

    Guo, Beiyuan; Gan, Weide; Fang, Weining

    2015-07-02

    Longitudinal acceleration comfort is one of the essential metrics used to evaluate the ride comfort of train. The aim of this study was to investigate the effectiveness of using hand grip force as a correlate of longitudinal acceleration comfort of rapid transit trains. In the paper, a motion simulation system was set up and a two-stage experiment was designed to investigate the role of the grip force on the longitudinal comfort of rapid transit trains. The results of the experiment show that the incremental grip force was linearly correlated with the longitudinal acceleration value, while the incremental grip force had no correlation with the direction of the longitudinal acceleration vector. The results also show that the effects of incremental grip force and acceleration duration on the longitudinal comfort of rapid transit trains were significant. Based on multiple regression analysis, a step function model was established to predict the longitudinal comfort of rapid transit trains using the incremental grip force and the acceleration duration. The feasibility and practicably of the model was verified by a field test. Furthermore, a comparative analysis shows that the motion simulation system and the grip force based model were valid to support the laboratory studies on the longitudinal comfort of rapid transit trains.

  5. Immediate and Delayed Effects of Forearm Kinesio Taping on Grip Strength

    PubMed Central

    Kouhzad Mohammadi, Hosein; Khademi Kalantari, Khosro; Naeimi, Sedighe Sadat; Pouretezad, Mohammad; Shokri, Esmaeil; Tafazoli, Mojdeh; Dastjerdi, Mahboobeh; Kardooni, Leila

    2014-01-01

    Background: Due to the fundamental role of gripping in most upper limb activities, grip strength promotion is a chief goal in the treatment of patients with upper limb musculoskeletal disorders. Kinesio taping is a novel and effective therapeutic technique believed to facilitate muscle contraction through stimulating mechanoreceptors and increasing the sensory feedback around the taped region. Objectives: The present study aimed to identify the best region (flexor, extensor and flexor/extensor regions) and time (immediate, 0.5, 1, 1.5, and 2 hours) of forearm Kinesio taping to obtain the maximum improvement in grip strength. Materials and Methods: In this longitudinal study, 40 healthy men and women (the mean age of 22.3 ± 2.19 years) were selected among students of Shahid Beheshti University of Medical Sciences, Tehran, Iran by simple, nonrandom sampling method. A dynamometer was used to measure grip strength immediately and every 30 minutes during the two hours after I-shaped application of tape (with 50% stretch) to the flexor, extensor, and flexor/extensor forearm muscles. Results: Grip strength was significantly increased in various muscle groups for males (P = 0.002) and females (P = 0.000) of the forearm and at different intervals for males (P = 0.000) and females (P = 0.000). Moreover, in both men and women, tape application to the extensor region provided greater grip strength compared to taping of the flexor and flexor/extensor regions (P = 0.000 for both). Furthermore, the maximum increase in grip strength were 0.5 (10.8% increase, P = 0.001) and 1.5 h (23.9% increase, P = 0.000) after taping in males and females, respectively. Conclusions: Taping the extensor region of forearm is recommended to achieve higher grip strength. Although grip strength increased at a slower pace in females than males, the final values were higher in women. PMID:25389492

  6. Memory for fingertip forces: passive hand muscle vibration interferes with predictive grip force scaling.

    PubMed

    Nowak, Dennis A; Rosenkranz, Karin; Hermsdörfer, Joachim; Rothwell, John

    2004-06-01

    When subjects repetitively lift an object, the grip force they select is influenced by the mechanical object properties of the preceding lift. Similar effects on grip force scaling are observed whether the subsequent lift is performed with the same hand or the hand contralateral to the preceding lift. Here we demonstrate that passive vibration of the hand muscles involved in the generation of grip force in the interval between two blocks of lifting trials interferes with predictive grip force scaling. Following ten trials in which subjects lifted an object with constant mechanical properties with the dominant hand, muscle vibration was given to the first interosseus and adductor pollicis muscles of the dominant hand during a 10-min rest period. Compared with the last lift preceding vibration, peak rates of grip force increase and peak grip forces were scaled too high during the first lift following vibration whether the lift was made with the dominant or non-dominant hand. Subjects scaled grip force accurately to the object properties within three lifts following vibration. If subjects rested for 10 min after the first ten trials and received no vibration, then there was no significant difference in the peak grip force or its rate of increase between the last lift preceding rest and the first lift following it. We suggest that vibration impairs the memory processes responsible for predictive grip force scaling. Our data are consistent with the recent suggestion that these memory processes are neither specific for a certain motor action nor do they reflect internal representations of mechanical object properties.

  7. Grip strength impairments among older adults receiving physical therapy in a home-care setting.

    PubMed

    Bohannon, Richard W

    2010-12-01

    A hand-grip dynamometer was used to assess the magnitude and prevalence of grip strength impairments among 41 home-care patients with diverse diagnoses (e.g., stroke, cancer, fracture, osteoarthritis). Based on published reference values, patients (as a whole) were weaker than normal for age and sex. The prevalence of weakness was 85.4% on one or the other side and 70.7% on both sides. Considering the prognostic importance of grip strength, this study emphasized the potential value of its measurement in a home-care population.

  8. Anticipatory grip force between 1 and 3g

    NASA Astrophysics Data System (ADS)

    White, Olivier; Van Loon, ing.. Jack J. W. A.; Thonnard, Jean-Louis; Hermsdorfer, Joachim; Lefevre, Philippe

    One remarkable capacity of utilizing common tools appropriately as soon as we grasp them relies on the ability to determine in advance the grip force (GF) required to handle them in relation to their mechanical properties and the surrounding environment. This anticipatory strategy avoids the uncompressible delays in the feedback system. The predictive control of GF is made possible because the nervous system can learn, store and then select the internal representations of the dynamics of innumerable objects, known as internal models. Beside this flexibility, the nervous system's ability to learn different task dynamics is often limited in classical robotic experiments The environment itself can be profoundly modified in altered gravity or centrifugation. The few studies that investigated motor adaptation in such contexts did not consider the interaction between gravitational phases and even less the transitions across environments. Here, we tested subject's abilities to adapt to levels of gravitational fields generated by a human centrifuge. In Experiment 1, seven subjects performed 4 lifting trials in each gravitational phase (1 to 2.5g and then 2.5 to 1g by steps of 0.5g) with a 0.12 kg instrumented object. In Experiment 2, six subjects performed vertical oscillations of the object during transitions between 1 and 3g (0.5g steps, ascending and descending phases, profile repeated twice). We continuously measured GF, load force (LF) and ambient gravity. We hypothesized that participants were able to predictively adjust GF to the new environment. In Experiment 1, participants adjusted their GF proportionally to gravity and decreased GF across trials within a given gravitational environment. Preload phases decreased over time from 300ms to 50ms irrespective of gravity. We quantified the abilities of participants to switch across environments by subtracting GF recorded in the last trial in the current gravity level from GF during the first trial in the new environment

  9. JPL Genesis and Rapid Intensification Processes (GRIP) Portal

    NASA Technical Reports Server (NTRS)

    Knosp, Brian W.; Li, P. Peggy; Vu, Quoc A.; Turk, Francis J.; Shen, Tsae-Pyng J.; Hristova-Veleva, Svetla M.; Licata, Stephen J.; Poulsen, William L.

    2012-01-01

    Satellite observations can play a very important role in airborne field campaigns, since they provide a comprehensive description of the environment that is essential for the experiment design, flight planning, and post-experiment scientific data analysis. In the past, it has been difficult to fully utilize data from multiple NASA satellites due to the large data volume, the complexity of accessing NASA s data in near-real-time (NRT), as well as the lack of software tools to interact with multi-sensor information. The JPL GRIP Portal is a Web portal that serves a comprehensive set of NRT observation data sets from NASA and NOAA satellites describing the atmospheric and oceanic environments related to the genesis and intensification of the tropical storms in the North Atlantic Ocean. Together with the model forecast data from four major global atmospheric models, this portal provides a useful tool for the scientists and forecasters in planning and monitoring the NASA GRIP field campaign during the 2010 Atlantic Ocean hurricane season. This portal uses the Google Earth plug-in to visualize various types of data sets, such as 2D maps, wind vectors, streamlines, 3D data sets presented at series of vertical cross-sections or pointwise vertical profiles, and hurricane best tracks and forecast tracks. Additionally, it allows users to overlap multiple data sets, change the opacity of each image layer, generate animations on the fly with selected data sets, and compare the observation data with the model forecast using two independent calendars. The portal also provides the capability to identify the geographic location of any point of interest. In addition to supporting the airborne mission planning, the NRT data and portal will serve as a very rich source of information during the post-field campaign analysis stage of the airborne experiment. By including a diverse set of satellite observations and model forecasts, it provides a good spatial and temporal context for the

  10. A continuous measure of fingertip friction during precision grip.

    PubMed

    André, Thibaut; Lefèvre, Philippe; Thonnard, Jean-Louis

    2009-05-15

    When humans manipulate an object, the minimal grip force (GF) required to avoid slipping depends on the frictional properties between the fingers and the object. As a consequence, fingertip skin friction plays a critical role during object manipulation. Here, the effects of the normal force and moisture content on the skin's static coefficient of friction (CF) for human fingertips were studied. Ten subjects were asked to pinch an object with a given normal force. Slippage of the object on the fingertips was generated for different ranges of normal force using a linear translation stage. The exerted forces and moisture of the fingertips were then measured, and the static coefficient of friction was calculated as the ratio between the tangential force and normal force at slippage. These results demonstrate that the effects of the normal force and moisture content on the CF exhibit a complex interaction. For a given moisture condition, the CF varies as a power function of the normal force; in contrast, for a given normal force, the CF is described by a "bell-shaped" function of moisture. A global expression of the CF as a function of the normal force and moisture content is derived, and a method is proposed for a continuous measure of the CF. This new method shall be of particular interest in investigating dexterous manipulation.

  11. Tactile afferents encode grip safety before slip for different frictions.

    PubMed

    Khamis, Heba A; Redmond, Stephen J; Macefield, Vaughan G; Birznieks, Ingvars

    2014-01-01

    Adjustments to frictional forces are crucial to maintain a safe grip during precision object handling in both humans and robotic manipulators. The aim of this work was to investigate whether a population of human tactile afferents can provide information about the current tangential/normal force ratio expressed as the percentage of the critical load capacity - the tangential/normal force ratio at which the object would slip. A smooth stimulation surface was tested on the fingertip under three frictional conditions, with a 4 N normal force and a tangential force generated by motion in the ulnar or distal direction at a fixed speed. During stimulation, the responses of 29 afferents (12 SA-I, 2 SA-II, 12 FA-I, 3 FA-II) were recorded. A multiple regression model was trained and tested using cross-validation to estimate the percentage of the critical load capacity in real-time as the tangential force increased. The features for the model were the number of spikes from each afferent in windows of fixed length (50, 100 or 200 ms) around points spanning the range from 50% to 100% of the critical load capacity, in 5% increments. The mean regression estimate error was less than 1% of the critical load capacity with a standard deviation between 5% and 10%. A larger number of afferents is expected to improve the estimate error. This work is important for understanding human dexterous manipulation and inspiring improvements in robotic grippers and prostheses.

  12. Similar motion of a hand-held object may trigger nonsimilar grip force adjustments.

    PubMed

    Gao, Fan; Latash, Mark L; Zatsiorsky, Vladimir M

    2007-01-01

    The tight coupling between load (L) and grip (G) forces during voluntary manipulation of a hand-held object is well established. The current study is to examine grip-load force coupling when motion of the hand with an object was either self-generated (voluntary) or externally generated. Subjects performed similar cyclic movements of different loads at various frequencies with three types of manipulations: 1) voluntary oscillation, 2) oscillating the right arm via the pulley system by the left leg (self-driven oscillation), and 3) oscillating the arm via the pulley system by another person (other-driven oscillation). During the self-generated movements: 1) the grip forces were larger and 2) grip-load force modulation was more pronounced than in the externally generated movements. The G-L adjustments are not completely determined by the mechanics of object motion; nonmechanical factors related to movement performance, for instance perceptual factors, may affect the G-L coupling.

  13. Gripping during climbing of arboreal snakes may be safe but not economical

    PubMed Central

    Byrnes, Greg; Jayne, Bruce C.

    2014-01-01

    On the steep surfaces that are common in arboreal environments, many types of animals without claws or adhesive structures must use muscular force to generate sufficient normal force to prevent slipping and climb successfully. Unlike many limbed arboreal animals that have discrete gripping regions on the feet, the elongate bodies of snakes allow for considerable modulation of both the size and orientation of the gripping region. We quantified the gripping forces of snakes climbing a vertical cylinder to determine the extent to which their force production favoured economy or safety. Our sample included four boid species and one colubrid. Nearly all of the gripping forces that we observed for each snake exceeded our estimate of the minimum required, and snakes commonly produced more than three times the normal force required to support their body weight. This suggests that a large safety factor to avoid slipping and falling is more important than locomotor economy. PMID:25142200

  14. Control of grip force and vertical posture while holding an object and being perturbed.

    PubMed

    Chen, Bing; Lee, Yun-Ju; Aruin, Alexander S

    2016-11-01

    We investigated motor control perspectives of coordinating maintenance of posture and application of grip force when holding an object and being perturbed. Ten subjects stood on the force platform holding an instrumented object in their dominant hand and were exposed to an external perturbation applied to their shoulders. Task demands were manipulated by positioning a slippery cap on top of the instrumented object. Grip force applied to the object, the object acceleration and the center of pressure (COP) were recorded and analyzed during the time intervals typical for the anticipatory (APA) and compensatory (CPA) components of postural control. Onsets of grip force were seen before the onsets of the COP displacement and initiation of movements of the handheld object during the APA phase of postural control, while the onsets of maximum grip force preceded the maximum COP displacement during the CPA phase. When the task demands increased by holding a handheld object with the slippery cap, subjects tended to generate grip force earlier and of a smaller magnitude; also, the COP displacement in the APA phase was smaller as compared to holding a handheld object only. The outcome provides a foundation for future studies of maintenance of vertical posture in people with impairments of balance and grip force control when holding an object and being perturbed.

  15. Fractal dimensions of pacing and grip force in drawing and handwriting production.

    PubMed

    Fernandes, David N; Chau, Tom

    2008-01-01

    We performed a repeated measures experiment to show that the pacing of a cyclic, ballistic drawing task has a fractal dimension. We also estimated the dimensionality of the force used to grip the drawing implement. Finally, we present an analysis of pediatric data to show that grip force has a fractal dimension in an actual handwriting task. In our experiment, subjects drew circles of varying sizes and at varying rates on a digitizing tablet, using a pen instrumented to measure radial force applied to its barrel. Subjects also drew circles in synchrony with a metronome. We found strong evidence for fractal scaling of both drawing period and grip force in the circle-drawing study. The dimensionality ranged from fractal Gaussian noise (fGn) to fractal Brownian motion, with Hurst coefficients clustering around the value for 1/f noise. When the subjects were required to synchronize their drawing with a metronome, the Hurst coefficient for the drawing period decreased, while the coefficient for grip force did not. This result indicates that independent processes control the variations in pacing and grip force. Grip force in the handwriting study also displayed fractal properties, with Hurst coefficients in the range of correlated fGn. We draw parallels between our handwriting measurements and studies of human gait.

  16. PICK1 interacts with ABP/GRIP to regulate AMPA receptor trafficking.

    PubMed

    Lu, Wei; Ziff, Edward B

    2005-08-04

    PICK1 and ABP/GRIP bind to the AMPA receptor (AMPAR) GluR2 subunit C terminus. Transfer of the receptor from ABP/GRIP to PICK1, facilitated by GluR2 S880 phosphorylation, may initiate receptor trafficking. Here we report protein interactions that regulate these steps. The PICK1 BAR domain interacts intermolecularly with the ABP/GRIP linker II region and intramolecularly with the PICK1 PDZ domain. Binding of PKCalpha or GluR2 to the PICK1 PDZ domain disrupts the intramolecular interaction and facilitates the PICK1 BAR domain association with ABP/GRIP. Interference with the PICK1-ABP/GRIP interaction impairs S880 phosphorylation of GluR2 by PKC and decreases the constitutive surface expression of GluR2, the NMDA-induced endocytosis of GluR2, and recycling of internalized GluR2. We suggest that the PICK1 interaction with ABP/GRIP is a critical step in controlling GluR2 trafficking.

  17. Hold, grasp, clutch or grab: consumer grip choices during food container opening.

    PubMed

    Rowson, J; Yoxall, A

    2011-07-01

    Society is ageing and sadly that ageing leads to a host of issues, not least a society in which the majority are likely to have some loss of strength and dexterity. This can lead to complications in undertaking everyday tasks such as using transport, bathing or even handling and opening food. Packaging has to provide a multitude of services; to protect and preserve the product, to provide information to the consumer and not least to allow access to the contents. This access to packaging--or 'openability'--has become a significant issue for designers and manufacturers with the change in demographics as described above. Understanding the choices consumers make in how they manipulate packaging can help designers produce packaging that is more able to meet the requirements of modern society. Studies previously undertaken by the authors showed that consumers did use different grips when opening packaging and that certain grips were theoretically more comfortable and stronger than others. This paper outlines a further study whereby consumers were asked to apply the most common grips to a specially designed torque measuring device. Details were taken about the consumers: age, gender, occupation, hand size, plus their preferred grip choice for packaging of this type. The study showed that typically women chose a grip that maximised their opportunity of opening the closure and that this grip choice was more limited than that available for men. This has implications for inclusive design of many everyday products.

  18. [Isometric grip strength and social gerontological research: results and analytic potentials of SHARE and SOEP].

    PubMed

    Hank, K; Jürges, H; Schupp, J; Wagner, G G

    2009-04-01

    This paper shows that the measurement of hand grip strength provides a non-invasive and reliable objective health indicator for social science research and is easy to collect in general population surveys. Grip strength is not only a useful complement of self-reported indicators of health, but it also exhibits a considerable predictive power with regard to a number of further relevant variables for social gerontological research, such as mortality risks. New data from the 2004 Survey of Health, Ageing and Retirement in Europe (SHARE) and the 2006 wave of the German Socio-Economic Panel Study (SOEP) allow insightful methodological and very first substantive cross-sectional analyses of grip strength in Germany. The focus of the present study is on the analysis of individuals aged 50 or older. The experience of both surveys when measuring grip strength is consistently positive, particularly with regard to the respondents' feedback. Major determinants of isometric grip strength are - beyond the individual's gender - age, body size and weight. A multivariate analysis also provides evidence for a clear positive association between various health indicators and grip strength.

  19. Posture, flexibility and grip strength in horse riders.

    PubMed

    Hobbs, Sarah Jane; Baxter, Joanna; Broom, Louise; Rossell, Laura-Ann; Sinclair, Jonathan; Clayton, Hilary M

    2014-09-29

    Since the ability to train the horse to be ambidextrous is considered highly desirable, rider asymmetry is recognized as a negative trait. Acquired postural and functional asymmetry can originate from numerous anatomical regions, so it is difficult to suggest if any is developed due to riding. The aim of this study was therefore to assess symmetry of posture, strength and flexibility in a large population of riders and to determine whether typical traits exist due to riding. 127 right handed riders from the UK and USA were categorized according to years riding (in 20 year increments) and their competition level (using affiliated test levels). Leg length, grip strength and spinal posture were measured and recorded by a physiotherapist. Standing and sitting posture and trunk flexibility were measured with 3-D motion capture technology. Right-left differences were explored in relation to years riding and rider competitive experience. Significant anatomical asymmetry was found for the difference in standing acromion process height for a competition level (-0.07±1.50 cm Intro/Prelim; 0.02±1.31 cm Novice; 0.43±1.27 cm Elementary+; p=0.048) and for sitting iliac crest height for years riding (-0.23±1.36 cm Intro/Prelim; 0.01±1.50 cm Novice; 0.86±0.41 cm Elementary+; p=0.021). For functional asymmetry, a significant interaction was found for lateral bending ROM for years riding x competition level (p=0.047). The demands on dressage riders competing at higher levels may predispose these riders to a higher risk of developing asymmetry and potentially chronic back pain rather than improving their symmetry.

  20. Posture, Flexibility and Grip Strength in Horse Riders

    PubMed Central

    Hobbs, Sarah Jane; Baxter, Joanna; Broom, Louise; Rossell, Laura-Ann; Sinclair, Jonathan; Clayton, Hilary M

    2014-01-01

    Since the ability to train the horse to be ambidextrous is considered highly desirable, rider asymmetry is recognized as a negative trait. Acquired postural and functional asymmetry can originate from numerous anatomical regions, so it is difficult to suggest if any is developed due to riding. The aim of this study was therefore to assess symmetry of posture, strength and flexibility in a large population of riders and to determine whether typical traits exist due to riding. 127 right handed riders from the UK and USA were categorized according to years riding (in 20 year increments) and their competition level (using affiliated test levels). Leg length, grip strength and spinal posture were measured and recorded by a physiotherapist. Standing and sitting posture and trunk flexibility were measured with 3-D motion capture technology. Right-left differences were explored in relation to years riding and rider competitive experience. Significant anatomical asymmetry was found for the difference in standing acromion process height for a competition level (−0.07±1.50 cm Intro/Prelim; 0.02±1.31 cm Novice; 0.43±1.27 cm Elementary+; p=0.048) and for sitting iliac crest height for years riding (−0.23±1.36 cm Intro/Prelim; 0.01±1.50 cm Novice; 0.86±0.41 cm Elementary+; p=0.021). For functional asymmetry, a significant interaction was found for lateral bending ROM for years riding x competition level (p=0.047). The demands on dressage riders competing at higher levels may predispose these riders to a higher risk of developing asymmetry and potentially chronic back pain rather than improving their symmetry. PMID:25414745

  1. Inertial torque during reaching directly impacts grip-force adaptation to weightless objects.

    PubMed

    Giard, T; Crevecoeur, F; McIntyre, J; Thonnard, J-L; Lefèvre, P

    2015-11-01

    A hallmark of movement control expressed by healthy humans is the ability to gradually improve motor performance through learning. In the context of object manipulation, previous work has shown that the presence of a torque load has a direct impact on grip-force control, characterized by a significantly slower grip-force adjustment across lifting movements. The origin of this slower adaptation rate remains unclear. On the one hand, information about tangential constraints during stationary holding may be difficult to extract in the presence of a torque. On the other hand, inertial torque experienced during movement may also potentially disrupt the grip-force adjustments, as the dynamical constraints clearly differ from the situation when no torque load is present. To address the influence of inertial torque loads, we instructed healthy adults to perform visually guided reaching movements in weightlessness while holding an unbalanced object relative to the grip axis. Weightlessness offered the possibility to remove gravitational constraints and isolate the effect of movement-related feedback on grip force adjustments. Grip-force adaptation rates were compared with a control group who manipulated a balanced object without any torque load and also in weightlessness. Our results clearly show that grip-force adaptation in the presence of a torque load is significantly slower, which suggests that the presence of torque loads experienced during movement may alter our internal estimates of how much force is required to hold an unbalanced object stable. This observation may explain why grasping objects around the expected location of the center of mass is such an important component of planning and control of manipulation tasks.

  2. Longitudinal assessment of grip strength using bulb dynamometer in Duchenne Muscular Dystrophy

    PubMed Central

    Pizzato, Tatiana M.; Baptista, Cyntia R. J. A.; Souza, Mariana A.; Benedicto, Michelle M. B.; Martinez, Edson Z.; Mattiello-Sverzut, Ana C.

    2014-01-01

    BACKGROUND: Grip strength is used to infer functional status in several pathological conditions, and the hand dynamometer has been used to estimate performance in other areas. However, this relationship is controversial in neuromuscular diseases and studies with the bulb dynamometer comparing healthy children and children with Duchenne Muscular Dystrophy (DMD) are limited. OBJECTIVE: The evolution of grip strength and the magnitude of weakness were examined in boys with DMD compared to healthy boys. The functional data of the DMD boys were correlated with grip strength. METHOD: Grip strength was recorded in 18 ambulant boys with DMD (Duchenne Group, DG) aged 4 to 13 years (mean 7.4±2.1) and 150 healthy volunteers (Control Group, CG) age-matched using a bulb dynamometer (North Coast- NC70154). The follow-up of the DG was 6 to 33 months (3-12 sessions), and functional performance was verified using the Vignos scale. RESULTS: There was no difference between grip strength obtained by the dominant and non-dominant side for both groups. Grip strength increased in the CG with chronological age while the DG remained stable or decreased. The comparison between groups showed significant difference in grip strength, with CG values higher than DG values (confidence interval of 95%). In summary, there was an increment in the differences between the groups with increasing age. Participants with 24 months or more of follow-up showed a progression of weakness as well as maintained Vignos scores. CONCLUSIONS: The amplitude of weakness increased with age in the DG. The bulb dynamometer detected the progression of muscular weakness. Functional performance remained virtually unchanged in spite of the increase in weakness. PMID:25003277

  3. Grip Strength as a Marker of Hypertension and Diabetes in Healthy Weight Adults

    PubMed Central

    Mainous, Arch G.; Tanner, Rebecca J.; Anton, Stephen D.; Jo, Ara

    2015-01-01

    Introduction Muscle strength may play a role in cardiometabolic disease. We examined the relationship between hand grip strength and diabetes and hypertension in a sample of healthy weight adults. Methods In 2015, we analyzed the National Health and Nutrition Examination Survey 2011–2012 for adults aged ≥20 years with healthy BMIs (between 18.5 and <25 kg/m2) and no history of cardiovascular disease (unweighted n=1,469; weighted n=61,672,082). Hand grip strength was assessed with a dynamometer. Diabetes was based on hemoglobin A1c level and reported diabetes diagnosis. Hypertension was based on measured blood pressure and reported hypertension diagnosis. Results Individuals with undiagnosed diabetes compared with individuals without diabetes had lower grip strength (51.9 vs 69.8, p=0.0001), as well as among individuals with diagnosed diabetes compared with individuals without diabetes (61.7 vs 69.8, p=0.008). Mean grip strength was lower among individuals with undiagnosed hypertension compared with individuals without hypertension (63.5 vs 71.5, p=0.008) as well as among individuals with diagnosed hypertension compared with those without hypertension (60.8 vs 71.5, p<0.0001). In adjusted analyses controlling for age, sex, race, smoking status, and first-degree relative with disease, mean grip strength was lower for undiagnosed diabetes (β= −10.02, p<0.0001) and diagnosed diabetes (β= −8.21, p=0.03) compared with individuals without diabetes. In adjusted analyses, grip strength was lower among individuals with undiagnosed hypertension (β= −6.6, p=0.004) and diagnosed hypertension (β= −4.27, p=0.04) compared with individuals without hypertension. Conclusions Among healthy weight adults, combined grip strength is lower in individuals with diagnosed and undiagnosed diabetes and hypertension. PMID:26232901

  4. Effects of bat composition, grip firmness, and impact location on postimpact ball velocity.

    PubMed

    Weyrich, A S; Messier, S P; Ruhmann, B S; Berry, M J

    1989-04-01

    The purpose of this investigation was to examine the effects of bat composition (aluminum and wooden), impact location [center of percussion (COP), center of gravity (COG), and end of the bat (E)], and grip firmness [tight (T) and no tension (NT)] on postimpact ball velocity. With the bats placed alternately in NT and T conditions, baseballs were delivered at a speed of 27.1 m.s-1 from a pitching machine positioned 1.5 m from the bat. High-speed photography (400 fps) was performed using a Locam camera positioned 7.54 m from and perpendicular to the principal plane of ball movement. A three-way ANCOVA revealed significant (P less than 0.01) differences in postimpact ball velocity between the three impact locations, with the COP yielding the greatest values, followed by the COG and E. Moreover, there was a significant (P less than 0.01) grip vs bat interaction. A simple-effects procedure revealed the following results: 1) the T grip produced greater (P less than 0.01) velocities than the NT grip across the aluminum (Al) bat; 2) there was no difference (P greater than 0.01) between the T and NT grips across the wooden (W) bat; 3) the W bat produced greater (P less than 0.01) velocities than the Al bat across the NT grip; and 4) there was no difference (P greater than 0.01) between the Al and W bats across the T grip.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Note: investigation on the influences of gripping methods on elastic modulus by a miniature tensile device and in situ verification.

    PubMed

    Ma, Z C; Zhao, H W; Wang, K T; Zhou, X Q; Hu, X L; Lu, S; Cheng, H B

    2013-06-01

    In this paper, by gripping the specimen on various positions, including the gripping section, stress concentration transition section, and gauge length section, theoretical analysis on the influences of gripping methods on tensile elastic modulus calculation was investigated with a group of equations. Then, an image-based displacement measurement system was implemented, and the experimental verification via in situ tensile testing was carried out to verify the feasibility of the theoretical analysis by a miniature tensile device integrated with a metallographic microscope. The stress-strain curves of 2026 aluminum alloy were also obtained by gripping the specimens on various positions to illustrate the influences of gripping methods. The influence of gripping methods on elongation measurement was also investigated. This paper showed a modular calculation method of elastic modulus for the tensile testing of typical plate specimens.

  6. Threshold position control of arm movement with anticipatory increase in grip force.

    PubMed

    Pilon, Jean-François; De Serres, Sophie J; Feldman, Anatol G

    2007-07-01

    The grip force holding an object between fingers usually increases before or simultaneously with arm movement thus preventing the object from sliding. We experimentally analyzed and simulated this anticipatory behavior based on the following notions. (1) To move the arm to a new position, the nervous system shifts the threshold position at which arm muscles begin to be recruited. Deviated from their activation thresholds, arm muscles generate activity and forces that tend to minimize this deviation by bringing the arm to a new position. (2) To produce a grip force, with or without arm motion, the nervous system changes the threshold configuration of the hand. This process defines a threshold (referent) aperture (R(a)) of appropriate fingers. The actual aperture (Q(a)) is constrained by the size of the object held between the fingers whereas, in referent position R(a), the fingers virtually penetrate the object. Deviated by the object from their thresholds of activation, hand muscles generate activity and grip forces in proportion to the gap between the Q(a) and R(a). Thus, grip force emerges since the object prevents the fingers from reaching the referent position. (3) From previous experiences, the system knows that objects tend to slide off the fingers when arm movements are made and, to prevent sliding, it starts narrowing the referent aperture simultaneously with or somewhat before the onset of changes in the referent arm position. (4) The interaction between the fingers and the object is accomplished via the elastic pads on the tips of fingers. The pads are compressed not only due to the grip force but also due to the tangential inertial force ("load") acting from the object on the pads along the arm trajectory. Compressed by the load force, the pads move back and forth in the gap between the finger bones and object, thus inevitably changing the normal component of the grip force, in synchrony with and in proportion to the load force. Based on these notions

  7. Similar motion of a handheld object may trigger non-similar grip force adjustments

    PubMed Central

    Gao, Fan; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2007-01-01

    The tight coupling between load (L) and grip (G) forces during voluntary manipulation of a hand-held object is well established. The current study is to examine grip-load force coupling when motion of the hand with an object was either self-generated (voluntary) or externally generated. Subjects performed similar cyclic movements of different loads at various frequencies with three types of manipulation: (a) voluntary oscillation, (b) oscillating the right arm via the pulley system by the left leg (self-driven oscillation), (c) oscillating the arm via the pulley system by another person (other-driven oscillation). During the self-generated movements: (a) the grip forces were larger and (b) grip-load force modulation was more pronounced than in the externally generated movements. The G-L adjustments are not completely determined by the mechanics of object motion; non-mechanical factors related to movement performance, for instance perceptual factors, may affect the G-L coupling. Potentially the results of study can be used to provide hand therapists with another way for administering the Rapid Exchange Gripping Test. PMID:17954351

  8. The effect of upper extremity fatigue on grip strength and passing accuracy in junior basketball players.

    PubMed

    Ahmed, Taghread

    2013-01-01

    Fatigue is an unavoidable part of a basketball game, which may affect an athlete's performance. The aim of this study was to investigate the effect of upper extremity fatigue on grip strength and passing accuracy in basketball, and ascertain if the effects of different fatigue protocols on grip strength and passing accuracy are the same. Twenty-four juniors under 18 years old (age: 16.75 ± 0.62 years; body height: 184.5 ± 3.31 cm; body mass: 77.25 ± 3.22 kg) volunteered to participate in the study, and were divided into two groups. After a warm-up, both groups performed the basketball passing test and grip strength was recorded for each group under three different testing conditions: rest, 70% and 90% exercise intensity. The protocol used for the first group was the chest press, and for the second group the wrist curls. Results show that after the upper extremity fatigue protocol all parameters of the study (grip strength and passing accuracy) showed a significant decrease, and there was no significant difference between both groups regarding grip strength and passing accuracy. The study suggested that in order to avoid upper extremity fatigue, basketball trainers and coaches need to include upper extremity conditioning exercises into their training sessions.

  9. The influence of golf shaft stiffness on grip and clubhead kinematics.

    PubMed

    MacKenzie, Sasho J; Boucher, Daniel E

    2017-01-01

    The purpose of this study was to investigate the influence of shaft stiffness on grip and clubhead kinematics. Two driver shafts with disparate levels of stiffness, but very similar inertial properties, were tested by 33 golfers representing a range of abilities. Shaft deflection data as well as grip and clubhead kinematics were collected from 14 swings, with each shaft, for each golfer using an optical motion capture system. The more flexible shaft (R-Flex) demonstrated a higher contribution to clubhead speed from shaft deflection dynamics (P < .001), but was also associated with significantly less grip angular velocity at impact (P = .001), resulting in no significant difference in clubhead speed (P = .14). However, at the individual level, half of the participants demonstrated a significant difference in clubhead speed between shafts. The more flexible shaft was also associated with significantly different magnitudes of head rotation relative to the grip. More specifically, both bend loft (P < .001) and bend lie (P < .001) were greater for the R-Flex shaft, while bend close (P = .017) was greater for the stiffer (X-Flex) shaft. However, changes in grip orientation resulted in no significant differences in face orientation, between the shafts, at impact.

  10. Decoding gripping force based on local field potentials recorded from subthalamic nucleus in humans

    PubMed Central

    Tan, Huiling; Pogosyan, Alek; Ashkan, Keyoumars; Green, Alexander L; Aziz, Tipu; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Brown, Peter

    2016-01-01

    The basal ganglia are known to be involved in the planning, execution and control of gripping force and movement vigour. Here we aim to define the nature of the basal ganglia control signal for force and to decode gripping force based on local field potential (LFP) activities recorded from the subthalamic nucleus (STN) in patients with deep brain stimulation (DBS) electrodes. We found that STN LFP activities in the gamma (55–90 Hz) and beta (13–30m Hz) bands were most informative about gripping force, and that a first order dynamic linear model with these STN LFP features as inputs can be used to decode the temporal profile of gripping force. Our results enhance the understanding of how the basal ganglia control gripping force, and also suggest that deep brain LFPs could potentially be used to decode movement parameters related to force and movement vigour for the development of advanced human-machine interfaces. DOI: http://dx.doi.org/10.7554/eLife.19089.001 PMID:27855780

  11. Sex Differences in Fear of Falling among Older Adults with Low Grip Strength

    PubMed Central

    LIM, Eunju

    2016-01-01

    Background: Fear of falling is not only a risk factor for falls, but it is also an important clinical predictor of functional decline in older adults. This study identified sex differences in fear of falling and related factors in older adults with low grip strength. Methods: The data of 902 older adults from the 2012 Korean National Survey, conducted as a research project by the Korea Employment Information Service, were analyzed. Grip strength, activities of daily living, cognitive function, depressive symptoms, and fear of falling were assessed. Multiple regression analysis was performed by a simultaneous data entry method. Results: Fear of falling was greater in older women with low grip strength than in their male equivalents (P<0.001). Regression analysis showed that age, fall experience within the previous 2 yr, activities of daily living, and depressive symptoms collectively accounted for 15.3% (P<0.001) of the variance among men. Meanwhile, age, fall experience within the previous 2 yr, grip strength, activities of daily living, and depressive symptoms collectively accounted for 13.4% (P<0.001) of the variance among women. Conclusion: Thus, the predictors of fear of falling differ between older men and women with low grip strength. Therefore, sex differences must be considered when developing intervention strategies for reducing fear of falling in this demographic. PMID:27398329

  12. Influence of dynamic hand-grip exercise on acetone in gas emanating from human skin.

    PubMed

    Mori, Kenji; Funada, Toshiaki; Kikuchi, Maasa; Ohkuwa, Tetsuo; Itoh, Hiroshi; Yamazaki, Yoshihiko; Tsuda, Takao

    2008-01-01

    This study investigated the effects of dynamic hand-grip exercise on skin-gas acetone concentration. The subjects for this experiment were seven healthy males. In the first experiment, to ascertain the reproducibility of the results for the skin-gas acetone concentration test, the skin gas was collected four times from one subject. In the second experiment, all subjects performed three different types of exercise (Exercises I-III) for a duration of 60 s. Exercise I was performed at 10 kg with one contraction every 3 s. Exercise II was 30 kg with one contraction every 3 s. Exercise III was 10 kg with one contraction per second. Acetone concentration was analyzed by gas chromatography. In the first experiment, reasonable reproducibility was obtained in measurements of skin-gas acetone concentration during the hand-grip exercise. In the second experiment, acetone concentration in skin gas during hand-grip exercise II was significantly higher than the basal level. Although skin-gas acetone levels increased in all subjects during exercises I and III, a significant difference was not found. No significant difference was found in skin-gas acetone concentration during dynamic hand-grip exercise among exercises I, II, and III. This study confirmed that skin-gas acetone levels increase during dynamic hand-grip exercise.

  13. Grip pressure distributions and associated variability in golf: a two-club comparison.

    PubMed

    Langlais, Sean M; Broker, Jeffrey P

    2014-06-01

    Teaching and playing professionals offer multiple theories concerning the manner in which forces should be applied to the handle of the club during the golf swing. This study extends recent research concerning grip pressures and forces in golf, with the purpose of exploring the similarities and differences between force profiles for a 7-iron and driver swung by proficient golfers. A secondary purpose was to further analyze the way that golfers use grip forces to manipulate the club. Grip forces were measured on eight low handicap golfers (USGA indexes 0 to 7) swinging their own 7-irons and drivers. In total, lead-hand and trail-hand grip forces were isolated as well as anatomically specific forces within the hands. Force profile variability across multiple swings for each golfer and between golfers characterized consistencies and important differences. Correlations between 7-iron and driver force profiles characterized force 'signatures.' The data highlight large fluctuations in grip forces during the swing. Marked differences between participants were observed, involving force magnitudes and phasing. Dominant forces arose primarily from the lead hand, specifically the last three fingers. Force profiles were highly repeatable across swings for a golfer (standard deviations < 7% of total force) and force profile correlations between 7-iron and driver for a golfer were remarkably high (r2 = 0.86). Notably, within swing force variability was greatest during club acceleration, but dramatically decreased at impact.

  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. Estimating thumb-index finger precision grip and manipulation potential in extant and fossil primates.

    PubMed

    Feix, Thomas; Kivell, Tracy L; Pouydebat, Emmanuelle; Dollar, Aaron M

    2015-05-06

    Primates, and particularly humans, are characterized by superior manual dexterity compared with other mammals. However, drawing the biomechanical link between hand morphology/behaviour and functional capabilities in non-human primates and fossil taxa has been challenging. We present a kinematic model of thumb-index precision grip and manipulative movement based on bony hand morphology in a broad sample of extant primates and fossil hominins. The model reveals that both joint mobility and digit proportions (scaled to hand size) are critical for determining precision grip and manipulation potential, but that having either a long thumb or great joint mobility alone does not necessarily yield high precision manipulation. The results suggest even the oldest available fossil hominins may have shared comparable precision grip manipulation with modern humans. In particular, the predicted human-like precision manipulation of Australopithecus afarensis, approximately one million years before the first stone tools, supports controversial archaeological evidence of tool-use in this taxon.

  16. Two cases of firearm grip impressions on the hands of suicide victims.

    PubMed

    Poulos, Christopher K; Peterson, Brian L

    2012-03-01

    Many factors are used to help distinguish firearm suicides from homicides and accidents, including range of fire, location of entrance defects, wound path trajectory, backspatter (blowback), and gunshot residue. Specifically, authors have discussed examination of the hands for backspatter, gunshot residue, cylinder gap effects, iron staining, and trauma as means of supporting a person having held a firearm while committing suicide. Here, we discuss 2 cases where suicidal gunshot wounds were accompanied by unique firearm grip impressions on the hands of the decedents. In 1 case, a "negative"[ impression of a grip pattern was left in a decedent's hand and in another case a grip pattern was left on the decedent's hand in dried blood. Such impressions can be used to provide support for establishing suicide as the manner of death.

  17. Estimating thumb–index finger precision grip and manipulation potential in extant and fossil primates

    PubMed Central

    Feix, Thomas; Kivell, Tracy L.; Pouydebat, Emmanuelle; Dollar, Aaron M.

    2015-01-01

    Primates, and particularly humans, are characterized by superior manual dexterity compared with other mammals. However, drawing the biomechanical link between hand morphology/behaviour and functional capabilities in non-human primates and fossil taxa has been challenging. We present a kinematic model of thumb–index precision grip and manipulative movement based on bony hand morphology in a broad sample of extant primates and fossil hominins. The model reveals that both joint mobility and digit proportions (scaled to hand size) are critical for determining precision grip and manipulation potential, but that having either a long thumb or great joint mobility alone does not necessarily yield high precision manipulation. The results suggest even the oldest available fossil hominins may have shared comparable precision grip manipulation with modern humans. In particular, the predicted human-like precision manipulation of Australopithecus afarensis, approximately one million years before the first stone tools, supports controversial archaeological evidence of tool-use in this taxon. PMID:25878134

  18. Maximal intermittent handgrip strategy: design and evaluation of an exercise protocol and a grip tool

    PubMed Central

    Bentley, Danielle Christine; Thomas, Scott Gordon

    2016-01-01

    Handgrip (HG) exercise has been prescribed as a lifestyle intervention to successfully reduce resting blood pressure (BP) among heterogeneous groups of participants. Current HG protocols have limited accessibility due to complicated exercise prescriptions and sophisticated required equipment. Therefore, this research describes the design and evaluation of the maximal intermittent (MINT) HG exercise strategy, consisting of both a novel exercise protocol (32×5 seconds maximal grip squeezes separated by 5 seconds of rest between sets) and an original grip tool. This research was a multistep progressive design that included 51 postmenopausal women as participants in three separate research studies. Part 1 of this research focuses on the MINT exercise protocol. A literature-informed rationale for the design of the protocol is described. This includes exercise intensity, work-to-rest ratio, and total exercise duration with reference to the unique physiology (mechanoreflex and metaboreflex) of postmenopausal women. Subsequent experimental analyses of acute responses to the MINT protocol revealed that women produced 50% of their maximum grip force with moderate cardiovascular responses (increases of systolic BP: 41.6 mmHg, diastolic BP: 20.1 mmHg, heart rate: 35.1 bpm) that remained far below the thresholds of concern identified by the American College of Sports Medicine. Part 2 of this research describes the creation of a novel grip tool, beginning with a mixed-methods assessment of participant opinions regarding two distinct in-laboratory grip tools, leading to the creation of four prototype MINT tools. Structured focus groups revealed a strong preference for MINT prototype 1 for all tool design features, including color, shape, size, and foam grip. Collectively, the result of this multistep research is a novel HG exercise strategy with enhanced accessibility by being easy to understand and simple to execute. The long-term training effectiveness of MINT as an exercise

  19. Anticipatory scaling of grip forces when lifting objects of everyday life.

    PubMed

    Hermsdörfer, Joachim; Li, Yong; Randerath, Jennifer; Goldenberg, Georg; Eidenmüller, Sandra

    2011-07-01

    The ability to predict and anticipate the mechanical demands of the environment promotes smooth and skillful motor actions. Thus, the finger forces produced to grasp and lift an object are scaled to the physical properties such as weight. While grip force scaling is well established for neutral objects, only few studies analyzed objects known from daily routine and none studied grip forces. In the present study, eleven healthy subjects each lifted twelve objects of everyday life that encompassed a wide range of weights. The finger pads were covered with force sensors that enabled the measurement of grip force. A scale registered load forces. In a control experiment, the objects were wrapped into paper to prevent recognition by the subjects. Data from the first lift of each object confirmed that object weight was anticipated by adequately scaled forces. The maximum grip force rate during the force increase phase emerged as the most reliable measure to verify that weight was actually predicted and to characterize the precision of this prediction, while other force measures were scaled to object weight also when object identity was not known. Variability and linearity of the grip force-weight relationship improved for time points reached after liftoff, suggesting that sensory information refined the force adjustment. The same mechanism seemed to be involved with unrecognizable objects, though a lower precision was reached. Repeated lifting of the same object within a second and third presentation block did not improve the precision of the grip force scaling. Either practice was too variable or the motor system does not prioritize the optimization of the internal representation when objects are highly familiar.

  20. Does visually induced self-motion affect grip force when holding an object?

    PubMed

    Bringoux, Lionel; Lepecq, Jean-Claude; Danion, Frédéric

    2012-09-01

    Accurate control of grip force during object manipulation is necessary to prevent the object from slipping, especially to compensate for the action of gravitational and inertial forces resulting from hand/object motion. The goal of the current study was to assess whether the control of grip force was influenced by visually induced self-motion (i.e., vection), which would normally be accompanied by changes in object load. The main task involved holding a 400-g object between the thumb and the index finger while being seated within a virtual immersive environment that simulated the vertical motion of an elevator across floors. Different visual motions were tested, including oscillatory (0.21 Hz) and constant-speed displacements of the virtual scene. Different arm-loading conditions were also tested: with or without the hand-held object and with or without oscillatory arm motion (0.9 Hz). At the perceptual level, ratings from participants showed that both oscillatory and constant-speed motion of the elevator rapidly induced a long-lasting sensation of self-motion. At the sensorimotor level, vection compellingness altered arm movement control. Spectral analyses revealed that arm motion was entrained by the oscillatory motion of the elevator. However, we found no evidence that grip force used to hold the object was visually affected. Specifically, spectral analyses revealed no component in grip force that would mirror the virtual change in object load associated with the oscillatory motion of the elevator, thereby allowing the grip-to-load force coupling to remain unaffected. Altogether, our findings show that the neural mechanisms underlying vection interfere with arm movement control but do not interfere with the delicate modulation of grip force. More generally, those results provide evidence that the strength of the coupling between the sensorimotor system and the perceptual level can be modulated depending on the effector.

  1. Extraction of time and frequency features from grip force rates during dexterous manipulation.

    PubMed

    Mojtahedi, Keivan; Fu, Qiushi; Santello, Marco

    2015-05-01

    The time course of grip force from object contact to onset of manipulation has been extensively studied to gain insight into the underlying control mechanisms. Of particular interest to the motor neuroscience and clinical communities is the phenomenon of bell-shaped grip force rate (GFR) that has been interpreted as indicative of feedforward force control. However, this feature has not been assessed quantitatively. Furthermore, the time course of grip force may contain additional features that could provide insight into sensorimotor control processes. In this study, we addressed these questions by validating and applying two computational approaches to extract features from GFR in humans: 1) fitting a Gaussian function to GFR and quantifying the goodness of the fit [root-mean-square error, (RMSE)]; and 2) continuous wavelet transform (CWT), where we assessed the correlation of the GFR signal with a Mexican Hat function. Experiment 1 consisted of a classic pseudorandomized presentation of object mass (light or heavy), where grip forces developed to lift a mass heavier than expected are known to exhibit corrective responses. For Experiment 2, we applied our two techniques to analyze grip force exerted for manipulating an inverted T-shaped object whose center of mass was changed across blocks of consecutive trials. For both experiments, subjects were asked to grasp the object at either predetermined or self-selected grasp locations ("constrained" and "unconstrained" task, respectively). Experiment 1 successfully validated the use of RMSE and CWT as they correctly distinguished trials with versus without force corrective responses. RMSE and CWT also revealed that grip force is characterized by more feedback-driven corrections when grasping at self-selected contact points. Future work will examine the application of our analytical approaches to a broader range of tasks, e.g., assessment of recovery of sensorimotor function following clinical intervention, interlimb

  2. Clinical effectiveness of grip strength in predicting ambulation of elderly inpatients

    PubMed Central

    Beseler, MR; Rubio, C; Duarte, E; Hervás, D; Guevara, MC; Giner-Pascual, M; Viosca, E

    2014-01-01

    Background Assessing the clinical effectiveness of measuring grip strength as a prognostic tool in recovering ambulation in bed-confined frail elderly patients. Methods A prospective study was carried out with 50 elderly inpatients (mean age: 81.6 years old). Manual muscle test was used for checking strength of hip flexor muscles, hip abductor muscles and knee extensor muscles. Grip strength was assessed by hydraulic dynamometer. Walking ability was assessed by functional ambulation categories and Functional Classification of Sagunto Hospital Ambulation. Existence of cognitive impairment (Short Portable Mental Status of Pfeiffer) and comorbidity (abbreviated Charlson index) were considered to be confounding variables. Statistical analysis Simple comparisons and mixed models of multiple ordinal regression. Results The sample presented generalized weakness in scapular (mean 4.22) and pelvic (mean 3.82) muscle. Mean hand grip values were similar: 11.98 kg right hand; 11.70 kg left hand. The patients had lost walking ability. After treatment, there was a statistically significant for scapular waist strength (P=0.001), pelvic waist strength (P=0.005) and walking ability (P=0.001). A statistically significant relationship in the regression analysis was found between the grip (right and left hands) and walking ability post-treatment (P=0.009; odds ratio 1.14 and P=0.0014 odds ratio 1.113 for each walking scale). The confounding variables showed no statistical significance in the results. Conclusion Grip strength is associated with walking ability in hospitalized frail elderly. Grip strength assessment by hydraulic dynamometry is useful in patients with poor collaboration. Walking ability training in frail elderly inpatients is useful. PMID:25395842

  3. Relationship Between Grip and Pinch Strength and Activities of Daily Living in Stroke Patients

    PubMed Central

    Bae, Jung Hyun; Seo, Kyung Mook; Kim, Don-Kyu; Shin, Hyun Iee; Shin, Hye Eun

    2015-01-01

    Objective To investigate the relationship between grip and pinch strength and independence in activities of daily living (ADL) in stroke patients. Methods Medical records of 577 stroke patients from January 2010 to February 2013 were retrospectively reviewed. Patients' grip and pinch strength of both hemiplegic and non-hemiplegic hands and the Korean version of Modified Barthel Index (K-MBI) score were collected. These patients were divided into three groups: group A (onset duration: ≤3 months), group B (onset duration: >3 months and <2 years), and group C (onset duration: ≥2 years). The correlation between grip and pinch strength and the K-MBI score was analyzed. Results In group A (95 patients), the K-MBI score was significantly (p<0.05) correlated with the grip and pinch strength of both hands in patients with right hemiplegia. Significant (p<0.05) correlation between the K-MBI score and the grip and pinch strength of the hemiplegic hand was shown in patients with left hemiplegia. In group B (69 patients) and group C (73 patients), the K-MBI score was significantly (p<0.05) correlated with the grip and pinch strength of the hemiplegic hand. Conclusion Stroke patients in subacute stage mainly performed activities of daily living using their dominant hand. However, independence in ADL was associated with the strength of the affected dominant hand. For stroke patients in chronic and late chronic stages, their hand power of the affected hand was associated with independence in ADL regardless whether the dominant hand was affected. PMID:26605173

  4. Maximal intermittent handgrip strategy: design and evaluation of an exercise protocol and a grip tool.

    PubMed

    Bentley, Danielle Christine; Thomas, Scott Gordon

    2016-01-01

    Handgrip (HG) exercise has been prescribed as a lifestyle intervention to successfully reduce resting blood pressure (BP) among heterogeneous groups of participants. Current HG protocols have limited accessibility due to complicated exercise prescriptions and sophisticated required equipment. Therefore, this research describes the design and evaluation of the maximal intermittent (MINT) HG exercise strategy, consisting of both a novel exercise protocol (32×5 seconds maximal grip squeezes separated by 5 seconds of rest between sets) and an original grip tool. This research was a multistep progressive design that included 51 postmenopausal women as participants in three separate research studies. Part 1 of this research focuses on the MINT exercise protocol. A literature-informed rationale for the design of the protocol is described. This includes exercise intensity, work-to-rest ratio, and total exercise duration with reference to the unique physiology (mechanoreflex and metaboreflex) of postmenopausal women. Subsequent experimental analyses of acute responses to the MINT protocol revealed that women produced 50% of their maximum grip force with moderate cardiovascular responses (increases of systolic BP: 41.6 mmHg, diastolic BP: 20.1 mmHg, heart rate: 35.1 bpm) that remained far below the thresholds of concern identified by the American College of Sports Medicine. Part 2 of this research describes the creation of a novel grip tool, beginning with a mixed-methods assessment of participant opinions regarding two distinct in-laboratory grip tools, leading to the creation of four prototype MINT tools. Structured focus groups revealed a strong preference for MINT prototype 1 for all tool design features, including color, shape, size, and foam grip. Collectively, the result of this multistep research is a novel HG exercise strategy with enhanced accessibility by being easy to understand and simple to execute. The long-term training effectiveness of MINT as an exercise

  5. The determination of the operating range of a twin-grip control yoke through biomechanical means

    NASA Technical Reports Server (NTRS)

    Gaertner, K. P.

    1978-01-01

    A twin-grip control yoke was designed as an ergonomic case study that allows dual axis control inputs, both axes being rotational. Inputs are effected by rotating the grips. How the handles were designed with respect to their shape and size and how the angular range of the control yoke in both rotational axes was evaluated. The control yoke which requires two-hand operation was tested to determine its operating range. The intention of this investigation was to find out the optimal form of the control yoke and the maximum permissible range in both rotating axes. In these experiments controls had no spring resistance.

  6. Association between floating toe and toe grip strength in school age children: a cross-sectional study

    PubMed Central

    Tasaka, Seishiro; Matsubara, Keisuke; Nishiguchi, Shu; Fukutani, Naoto; Tashiro, Yuto; Shirooka, Hidehiko; Nozaki, Yuma; Hirata, Hinako; Yamaguchi, Moe; Matsushita, Tomofumi; Fukumoto, Takahiko; Aoyama, Tomoki

    2016-01-01

    [Purpose] This study investigated the association between floating toe and toe grip strength. [Subjects and Methods] A total of 635 Japanese children aged 9–11 years participated in this study. Floating toe was evaluated using footprint images, while toe grip strength was measured using a toe grip dynamometer. All 1,270 feet were classified into a floating toe group and a normal toe group according to visual evaluation of the footprint images. Intergroup differences in toe grip strength were analyzed using the unpaired t-test and logistic regression analysis adjusted for age, gender, and Rohrer Index. [Results] There were 512 feet (40.3%) in the floating toe group. Mean toe grip strength of the feet with floating toe was significantly lower than that of normal feet (floating toe group, 12.9 ± 3.7 kg; normal toe group, 13.6 ± 4.1 kg). In addition, lower toe grip strength was associated with floating toe on logistic regression analysis after adjustment for age, gender, and Rohrer Index (odds ratio, 0.954; 95% confidence interval, 0.925–0.984). [Conclusion] This study revealed that lower toe grip strength was significantly associated with floating toe. Therefore, increasing toe grip strength may play a role in preventing floating toe in school age children. PMID:27630423

  7. Descriptive analysis of the developmental progression of grip position for pencil and crayon control in nondysfunctional children.

    PubMed

    Schneck, C M; Henderson, A

    1990-10-01

    This study was designed to investigate the developmental progression in pencil and crayon grip. The subjects were 320 nondysfunctional children aged 3.0 to 6.11 years, with 20 boys and 20 girls at each 6-month age interval. On the basis of a review of the literature, developmental pencil and crayon grips were defined for the study, and the type of grips each child used to perform a drawing task and a coloring task were recorded. Many children at each age level used mature pencil grips. A developmental progression, however, was shown by the percentage change of children at each age level who used mature grips. Forty-eight percent of the youngest group used mature grips, compared with 90% of the oldest children. Two pencil grips-dynamic and lateral tripod-appear to be common in older children. Differences in the developmental progression of pencil grip were noted between boys and girls and between a drawing task and a coloring task.

  8. Activity-dependent synaptic GRIP1 accumulation drives synaptic scaling up in response to action potential blockade.

    PubMed

    Gainey, Melanie A; Tatavarty, Vedakumar; Nahmani, Marc; Lin, Heather; Turrigiano, Gina G

    2015-07-07

    Synaptic scaling is a form of homeostatic plasticity that stabilizes neuronal firing in response to changes in synapse number and strength. Scaling up in response to action-potential blockade is accomplished through increased synaptic accumulation of GluA2-containing AMPA receptors (AMPAR), but the receptor trafficking steps that drive this process remain largely obscure. Here, we show that the AMPAR-binding protein glutamate receptor-interacting protein-1 (GRIP1) is essential for regulated synaptic AMPAR accumulation during scaling up. Synaptic abundance of GRIP1 was enhanced by activity deprivation, directly increasing synaptic GRIP1 abundance through overexpression increased the amplitude of AMPA miniature excitatory postsynaptic currents (mEPSCs), and shRNA-mediated GRIP1 knockdown prevented scaling up of AMPA mEPSCs. Furthermore, knockdown and replace experiments targeting either GRIP1 or GluA2 revealed that scaling up requires the interaction between GRIP1 and GluA2. Finally, GRIP1 synaptic accumulation during scaling up did not require GluA2 binding. Taken together, our data support a model in which activity-dependent trafficking of GRIP1 to synaptic sites drives the forward trafficking and enhanced synaptic accumulation of GluA2-containing AMPAR during synaptic scaling up.

  9. Effect of grip type, wrist motion, and resistance level on pressures within the carpal tunnel of normal wrists.

    PubMed

    McGorry, Raymond W; Fallentin, Nils; Andersen, Johan H; Keir, Peter J; Hansen, Torben B; Pransky, Glenn; Lin, Jia-Hua

    2014-04-01

    Elevated carpal tunnel pressure (CTP) has been associated with carpal tunnel syndrome. This study systematically evaluated the effect of wrist motion resistance and grip type on CTP during wrist motion typical of occupational tasks. CTP during four wrist motion patterns, with and without resistance, and with and without gripping, was measured in vivo in 14 healthy individuals. CTP measured during compound motions fell between that measured in the cardinal planes of wrist flexion/extension and radial/ulnar deviation. Generally, with no active gripping there was little pressure change due to wrist angular displacement or resistance level. However, concurrent active pinch or power grip increased CTP particularly in motions including extension. CTP typically did not increase during wrist flexion, and in fact often decreased. Extension motions against resistance when employing a pinch or power grip increase CTP more than motions with flexion. Results could help inform design or modification of wrist motion intensive occupational tasks. © 2014 The Authors.

  10. Does grip strength on the unaffected side of patients with hemiparetic stroke reflect the strength of other ipsilateral muscles?

    PubMed Central

    Takahashi, Jumpei; Nishiyama, Toru; Matsushima, Yoshimasa

    2017-01-01

    [Purpose] Grip strength is used as an indicator of overall body muscular strength. However, most studies on grip strength have been performed in healthy people, and no study has evaluated it in the unaffected side of patients with hemiparetic stroke. The purpose of this study was to determine if grip strength on the unaffected side of patients with hemiparetic stroke correlates with the strength of other ipsilateral musculature. [Subjects and Methods] The maximal strengths of the muscles on the unaffected side of 31 patients with hemiparetic stroke were measured, and correlation coefficients were calculated. [Results] The results revealed significant positive correlations between grip strength on the unaffected side and the strength of the other ipsilateral muscle groups, with relatively high correlations being observed for the upper extremity muscle groups. [Conclusion] This suggests that grip strength on the unaffected side of patients with hemiparetic stroke can be used as a simple way to estimate overall strength on that side. PMID:28210040

  11. Does grip strength on the unaffected side of patients with hemiparetic stroke reflect the strength of other ipsilateral muscles?

    PubMed

    Takahashi, Jumpei; Nishiyama, Toru; Matsushima, Yoshimasa

    2017-01-01

    [Purpose] Grip strength is used as an indicator of overall body muscular strength. However, most studies on grip strength have been performed in healthy people, and no study has evaluated it in the unaffected side of patients with hemiparetic stroke. The purpose of this study was to determine if grip strength on the unaffected side of patients with hemiparetic stroke correlates with the strength of other ipsilateral musculature. [Subjects and Methods] The maximal strengths of the muscles on the unaffected side of 31 patients with hemiparetic stroke were measured, and correlation coefficients were calculated. [Results] The results revealed significant positive correlations between grip strength on the unaffected side and the strength of the other ipsilateral muscle groups, with relatively high correlations being observed for the upper extremity muscle groups. [Conclusion] This suggests that grip strength on the unaffected side of patients with hemiparetic stroke can be used as a simple way to estimate overall strength on that side.

  12. An automatic approach and grip method of micro-particle in 3D space

    NASA Astrophysics Data System (ADS)

    Zhang, Juan; Wu, Wenrong; Bi, Lie

    2017-03-01

    Micro-particle is hard to be observed as small scale and hard to be gripped as micro-force from substrate, an automatic approach and grip method of micro-particle in the guide of microscopic vision systems is proposed in the paper to grip micro-particle. First, the micro-gripper driven by electrostatic force is introduced and forces in gripping process are analyzed. Second, a micro-assembly robot composed of two microscopic vision systems is established to monitor micro-operation process and to operate micro-particle. Image features of micro-particle and micro-gripper end-effector are extracted by image feature extraction method to calculate relative position of micro-particle and micro-gripper in image space. Last, a movement control strategy in 3D space based on image Jacobian matrix is studied to control micro-gripper approach and align with micro-particle. Experimental results verified the effectiveness of proposed methods.

  13. Automated pressure map segmentation for quantifying phalangeal kinetics during cylindrical gripping.

    PubMed

    Sinsel, Erik W; Gloekler, Daniel S; Wimer, Bryan M; Warren, Christopher M; Wu, John Z; Buczek, Frank L

    2016-02-01

    Inverse dynamics models used to investigate musculoskeletal disorders associated with handle gripping require accurate phalangeal kinetics. Cylindrical handles wrapped with pressure film grids have been used in studies of gripping kinetics. We present a method fusing six degree-of-freedom hand kinematics and a kinematic calibration of a cylinder-wrapped pressure film. Phalanges are modeled as conic frusta and projected onto the pressure grid, automatically segmenting the pressure map into regions of interest (ROIs). To demonstrate the method, segmented pressure maps are presented from two subjects with substantially different hand length and body mass, gripping cylinders 50 and 70 mm in diameter. For each ROI, surface-normal force vectors were summed to create a reaction force vector and center of pressure location. Phalangeal force magnitudes for a data sample were similar to that reported in previous studies. To evaluate our method, a surrogate was designed for each handle such that when modeled as a phalanx it would generate a ROI around the cells under its supports; the classification F-score was above 0.95 for both handles. Both the human subject results and the surrogate evaluation suggest that the approach can be used to automatically segment the pressure map for quantifying phalangeal kinetics of the fingers during cylindrical gripping.

  14. Experimental study on the grip and hold strength for stanchions and handrails in buses.

    PubMed

    Uetake, Teruo; Shimoda, Masahiro

    2006-12-01

    The purpose of this study was to investigate the effective use of stanchions and handrails in buses. We constructed experimental equipment resembling bus stanchions and handrails and examined the grip and hold strength exerted when used. The total number of subjects was 80: 30 elderly and 19 young males, and 22 elderly and 9 young females. The experimental equipment comprised four parts: a handle part to imitate safety devices in buses such as stanchions, handrails, and straps, which was pulled by a winch at a constant speed; and a load cell wired with an analyzing processor, which output the strength exerted. The handle part was designed to measure grip and hold strengths against pulling forces in three directions, that is, forward, in the direction of the back of the hand, and in the direction of the palm. The subjects were asked to grasp the handle part against a pulling force. The maximum grip and hold strengths were recorded and analyzed. The strengths when pulled forward were the largest independent of the sex and age of the subjects. The results indicate that standing bus passengers should grip the fixtures, such as a stanchion, with their right hand when they are standing on the right side in a bus facing the windows.

  15. Abnormal capacity for grip force control in patients with congenital insensitivity to pain.

    PubMed

    Kawashima, Noritaka; Abe, Masaki O; Iwaya, Tsutomu; Haga, Nobuhiko

    2012-05-01

    Congenital insensitivity to pain (CIP), which is an extremely rare sensory neuropathy, is defined as the absence of normal responses to noxious stimuli. Although motor function is not directly impaired in CIP patients, it is likely that the sensory deficit affects the motor control system. In order to characterize motor capacity in CIP patients, we here measured grip force and acceleration of a held object in 12 patients with CIP and 12 age-matched able-bodied subjects. The results demonstrated that the grip force during the object grasp-lift-holding task was significantly greater, less reproducibility and greater fluctuation in the acceleration of the object in CIP patients than in normal subjects. Moreover, some patients showed absence of temporal coupling between the grip and load force, suggesting that anticipatory modulation of the grip force was at least partly impaired. As far as the authors know, this is the first study to characterize motor control ability in patients with CIP. The observed abnormal motor capacity can be at least partly attributed to a lack of sensory inputs mediated by Aδ and unmyelinated C-, specifically C-tactile, fibers. The present results may provide information useful for the prevention of secondary injury and education for patients during the developmental stage.

  16. Differential roles for NSF and GRIP/ABP in AMPA receptor cycling.

    PubMed

    Braithwaite, Steven P; Xia, Houhui; Malenka, Robert C

    2002-05-14

    alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) stability and movement at synapses are important factors controlling synaptic strength. Here, we study the roles of proteins [N-ethylmaleimide-sensitive fusion protein (NSF), glutamate receptor AMPAR binding protein (ABP)-interacting protein (GRIP)/(ABP), and protein interacting with C-kinase-1 (PICK1) that interact with the GluR2 subunit in the control of the surface expression and cycling of AMPARs. Epitope-tagged GluR2 formed functional receptors that exhibited targeting to synaptic sites. Constructs in which binding to NSF, PDZ proteins (GRIP/ABP and PICK1), or GRIP/ABP alone was eliminated each exhibited normal surface targeting and constitutive cycling. The lack of NSF binding, however, resulted in receptors that were endocytosed to a greater extent than wild-type receptors in response to application of AMPA or N-methyl-d-aspartate (NMDA). Conversely, the behavior of the GluR2 mutants incapable of binding to GRIP/ABP suggests that these PDZ proteins play a role in the stabilization of an intracellular pool of AMPARs that have been internalized on stimulation, thus inhibiting their recycling to the synaptic membrane. These results provide further evidence for distinct functional roles of GluR2-interacting proteins in AMPAR trafficking.

  17. Automated pressure map segmentation for quantifying phalangeal kinetics during cylindrical gripping

    PubMed Central

    Sinsel, Erik W.; Gloekler, Daniel S.; Wimer, Bryan M.; Warren, Christopher M.; Wu, John Z.; Buczek, Frank L.

    2016-01-01

    Inverse dynamics models used to investigate musculoskeletal disorders associated with handle gripping require accurate phalangeal kinetics. Cylindrical handles wrapped with pressure film grids have been used in studies of gripping kinetics. We present a method fusing six degree-of-freedom hand kinematics and a kinematic calibration of a cylinder-wrapped pressure film. Phalanges are modeled as conic frusta and projected onto the pressure grid, automatically segmenting the pressure map into regions of interest (ROIs). To demonstrate the method, segmented pressure maps are presented from two subjects with substantially different hand length and body mass, gripping cylinders 50 and 70 mm in diameter. For each ROI, surface-normal force vectors were summed to create a reaction force vector and center of pressure location. Phalangeal force magnitudes for a data sample were similar to that reported in previous studies. To evaluate our method, a surrogate was designed for each handle such that when modeled as a phalanx it would generate a ROI around the cells under its supports; the classification F-score was above 0.95 for both handles. Both the human subject results and the surrogate evaluation suggest that the approach can be used to automatically segment the pressure map for quantifying phalangeal kinetics of the fingers during cylindrical gripping. PMID:26709291

  18. An association of dominant hand grip strength with some anthropometric variables in Indian collegiate population.

    PubMed

    Koley, Shyamal; Singh, Arvinder Pal

    2009-03-01

    The present study deals with the correlations of dominant hand grip strength and 12 anthropometric variables, namely, height, weight, BMI, upper arm length, forearm length, total arm length, hand breadth, hand length, upper arm circumference, forearm circumference, biceps skinfold and triceps skinfold in randomly selected 303 unrelated, normal, healthy students (151 males and 152 females) aged 18-25 years of Guru Nanak Dev University, Amritsar, Punjab, India. The findings of the present study indicate a strong association of dominant right hand grip strength with all the anthropometric variables, except biceps skinfold in male students and with height (r = 0.200), weight (r = 0.275), BMI (p = 0.217), total arm length (p = 0.218) and upper arm circumference (r = 0.199) in female students. Statistically significant positive correlations were also found between dominant left hand grip strength and height (r = 0.275), weight (p = 0.537), BMI (p = 0.472), hand breadth (p = 0.464), upper arm circumference (r = 0.570), forearm circumference (p = 0.464) and triceps skinfold (p = 0.343) only in male students, but no such association was found between grip strength of left hand dominant female students with any of the twelve anthropometric variables. It may be concluded that hand dominance, especially of the right hand, has some close association with the anthropometric variables related to upper extremities.

  19. Grip Force Control Is Dependent on Task Constraints in Children with and without Developmental Coordination Disorder

    ERIC Educational Resources Information Center

    Law, Sui-Heung; Lo, Sing Kai; Chow, Susanna; Cheing, Gladys L.Y.

    2011-01-01

    Excessive grip force (GF) is often found in children with developmental coordination disorder (DCD). However, their GF control may vary when task constraints are imposed upon their motor performance. This study aimed to investigate how their GF control changes in response to task demands, and to examine their tactile sensitivity. Twenty-one…

  20. How Predictive Is Grip Force Control in the Complete Absence of Somatosensory Feedback?

    ERIC Educational Resources Information Center

    Nowak, Dennis A.; Glasauer, Stefan; Hermsdorfer, Joachim

    2004-01-01

    Grip force control relies on accurate internal models of the dynamics of our motor system and the external objects we manipulate. Internal models are not fixed entities, but rather are trained and updated by sensory experience. Sensory feedback signals relevant object properties and mechanical events, e.g. at the skin-object interface, to modify…

  1. 16 CFR Figure 5 to Part 1512 - Typical Handbrake Actuator Showing Grip Dimension

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Typical Handbrake Actuator Showing Grip Dimension 5 Figure 5 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 5 Figure 5 to Part 1512—Typical...

  2. 16 CFR Figure 5 to Part 1512 - Typical Handbrake Actuator Showing Grip Dimension

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Typical Handbrake Actuator Showing Grip Dimension 5 Figure 5 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 5 Figure 5 to Part 1512—Typical...

  3. 16 CFR Figure 5 to Part 1512 - Typical Handbrake Actuator Showing Grip Dimension

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Typical Handbrake Actuator Showing Grip Dimension 5 Figure 5 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 5 Figure 5 to Part 1512—Typical...

  4. 16 CFR Figure 5 to Part 1512 - Typical Handbrake Actuator Showing Grip Dimension

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Typical Handbrake Actuator Showing Grip Dimension 5 Figure 5 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 5 Figure 5 to Part 1512—Typical...

  5. 16 CFR Figure 5 to Part 1512 - Typical Handbrake Actuator Showing Grip Dimension

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Typical Handbrake Actuator Showing Grip Dimension 5 Figure 5 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 5 Figure 5 to Part 1512—Typical...

  6. Precision Grip in Congenital and Acquired Hemiparesis: Similarities in Impairments and Implications for Neurorehabilitation

    PubMed Central

    Bleyenheuft, Yannick; Gordon, Andrew M.

    2014-01-01

    Background: Patients with congenital and acquired hemiparesis incur long-term functional deficits, among which the loss of prehension that may impact their functional independence. Identifying, understanding, and comparing the underlying mechanisms of prehension impairments represent an opportunity to better adapt neurorehabilitation. Objective: The present review aims to provide a better understanding of precision grip deficits in congenital and acquired hemiparesis and to determine whether the severity and type of fine motor control impairments depend on whether or not the lesions are congenital or acquired in adulthood. Methods: Using combinations of the following key words: fingertip force, grip force, precision grip, cerebral palsy, stroke, PubMed, and Scopus databases were used to search studies from 1984 to 2013. Results: Individuals with both congenital and acquired hemiparesis were able to some extent to use anticipatory motor control in precision grip tasks, even if this control was impaired in the paretic hand. In both congenital and acquired hemiparesis, the ability to plan efficient anticipatory motor control when the less-affected hand is used provides a possibility to remediate impairments in anticipatory motor control of the paretic hand. Conclusion: Surprisingly, we observed very few differences between the results of studies in children with congenital hemiplegia and stroke patients. We suggest that the underlying specific strategies of neurorehabilitation developed for each one could benefit the other. PMID:25071502

  7. Earthquakes and Ice Cores Point to Wet Feet at the NorthGRIP Deep Drill Site

    NASA Astrophysics Data System (ADS)

    Dahl-Jensen, D.; Dahl-Jensen, T.; Gundestrup, N. S.

    2001-12-01

    A seismic broadband station was placed at the NorthGRIP deep drill site (75N, 42W) on the Greenland Ice Cap for the summer 2000. During the 2 month acquisition period 15 earthquakes with sufficient quality for Receiver Function analysis aimed at crust and mantle structure under NorthGRIP were recorded. The models are consistent with the presence of a thin sedimentary layer at the base of the ice. The seismic velocities in the sediments are lower than in the ice, indicating wet sediments. The results from the deep drilling program reveal high basal temperatures at the base of the 3080 m thick ice at NorthGRIP. The measured temperatures and the observed layer thickness' in the ice core indicate that there is basal melting of the order of 5 mm /yr. and that the geothermal heatflow is of the order of 100 mW/m2 (REF), much higher than expected. A detailed radio echo mapping of the bedrock show that NorthGRIP is located in a large, flat-bottomed valley, suggesting that the sediments observed are lacustrine. The thin layer of sediments cannot account for the unexpected high heatflow causing equally unexpected basal melting. The geology is presumed to be Precambrian. Heatflow determined in a similar way at the GRIP deep drill site (73N, 38W) is 51 mW/ m2 (Dahl-Jensen et al, 1998), more in line with expected values. Magnetic anomaly data do not indicate any volcanic structures, which could help explain the high heatflow. Gravity anomaly data show that NorthGRIP is located at the edge of marked gravity discontinuity. The cause of the discontinuity is not known, but "edge effects" could be speculated upon to be the cause of the high heatflow. D. Dahl-Jensen, N. Gundestrup, H. Miller, O. Watanabe, S.J. Johnsen, J.P. Steffensen, H.B. Clausen, A. Svensson, L.B. Larsen in press: The NorthGRIP drilling program. Annals of Glaciology, vol 35 D. Dahl-Jensen, K Mosegaard, N. Grundestrup, G.D. Clow, S.J. Johnson and N. Balling 1998: Past Temperatures Directly from the Greenland Ice

  8. Analysis of the statistical methods used to detect submaximal effort with the five-rung grip strength test.

    PubMed

    Shechtman, Orit; Gutierrez, Zeida; Kokendofer, Emily

    2005-01-01

    Controversy exists in the literature concerning the ability of the five-rung grip test to identify submaximal effort. The purpose of this study was to analyze four methods commonly used to evaluate the shape of the curve generated by maximal versus submaximal efforts. Thirty hand therapy patients performed the five-rung grip test maximally and submaximally with both their injured and uninjured hands. Grip strength scores were recorded at each of the five-rung positions. Next, four methods were used to analyze the data 1) visual analysis, 2) analysis of variance, 3) normalization, and 4) calculation of the standard deviation across the five strength scores. Analysis by all methods demonstrated that there were no differences between the injured hand exerting maximal effort and the uninjured hand exerting submaximal effort. In all four methods, the five-rung grip strength test was unable to distinguish between the injured hand exerting maximal effort and the uninjured hand exerting submaximal effort. The results suggest that the five-rung grip strength test should not be used to determine sincerity of effort in people with hand injuries, and that the shape of the curve generated by the five-rung grip strength test may not be related to level of effort but rather to the amount of force generated by the gripping hand.

  9. The development and validation of equations to predict grip force in the workplace: contributions of muscle activity and posture.

    PubMed

    Keir, Peter J; Mogk, Jeremy P M

    2005-08-15

    The inherent difficulty of measuring forces on the hand in ergonomic workplace assessments has led to the need for equations to predict grip force. A family of equations was developed, and validated, for the prediction of grip force using forearm electromyography (six finger and wrist muscles) as well as posture of the wrist (flexed, neutral and extended) and forearm (pronated, neutral, supinated). Inclusion of muscle activity was necessary to explain over 85% of the grip force variance and was further improved with wrist posture but not forearm posture. Posture itself had little predictive power without muscle activity (<1%). Nominal wrist posture improved predictive power more than the measured wrist angle. Inclusion of baseline muscle activity, the activity required to simply hold the grip dynamometer, greatly improved grip force predictions, especially at low force levels. While the complete model using six muscles and posture was the most accurate, the detailed validation and error analysis revealed that equations based on fewer components often resulted in a negligible reduction in predictive strength. Error was typically less than 10% under 50% of maximal grip force and around 15% over 50% of maximal grip force. This study presents detailed error analyses to both improve upon previous studies and to allow an educated decision to be made on which muscles to monitor depending on expected force levels, costs and error deemed acceptable by the potential user.

  10. First flight of the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument

    NASA Astrophysics Data System (ADS)

    Duncan, Nicole; Saint-Hilaire, P.; Shih, A. Y.; Hurford, G. J.; Bain, H. M.; Amman, M.; Mochizuki, B. A.; Hoberman, J.; Olson, J.; Maruca, B. A.; Godbole, N. M.; Smith, D. M.; Sample, J.; Kelley, N. A.; Zoglauer, A.; Caspi, A.; Kaufmann, P.; Boggs, S.; Lin, R. P.

    2016-07-01

    The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument is a balloon-borne telescope designed to study solar- are particle acceleration and transport. We describe GRIPS's first Antarctic long-duration flight in January 2016 and report preliminary calibration and science results. Electron and ion dynamics, particle abundances and the ambient plasma conditions in solar flares can be understood by examining hard X-ray (HXR) and gamma-ray emission (20 keV to 10 MeV). Enhanced imaging, spectroscopy and polarimetry of are emissions in this energy range are needed to study particle acceleration and transport questions. The GRIPS instrument is specifically designed to answer questions including: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? GRIPS's key technological improvements over the current solar state of the art at HXR/gamma-ray energies, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), include 3D position-sensitive germanium detectors (3D-GeDs) and a single-grid modulation collimator, the multi-pitch rotating modulator (MPRM). The 3D-GeDs have spectral FWHM resolution of a few hundred keV and spatial resolution <1 mm3. For photons that Compton scatter, usually > 150 keV, the energy deposition sites can be tracked, providing polarization measurements as well as enhanced background reduction through Compton imaging. Each of GRIPS's detectors has 298 electrode strips read out with ASIC/FPGA electronics. In GRIPS's energy range, indirect imaging methods provide higher resolution than focusing optics or Compton imaging techniques. The MPRM gridimaging system has a single-grid design which provides twice the throughput of a bi-grid imaging system like RHESSI. The grid is

  11. The relationship between hand anthropometrics, total grip strength and individual finger force for various handle shapes.

    PubMed

    Kong, Yong-Ku; Kim, Dae-Min

    2015-01-01

    The design and shape of hand tool handles are critical factors for preventing musculoskeletal disorders (MSDs) caused by the use of hand tools. We explored how these factors are related to total force and individual finger force in males and females with various hand anthropometrics. Using the MFFM system, we assessed four indices of anthropometry, and measured total force and individual finger force on various handle designs and shapes. Both total force and individual finger force were significant according to gender and handle shape. Total grip strength to the handle shape indicated the greatest strength with D shape and the least with A shape. From the regression analysis of hand anthropometric indices, the value of R was respectably high at 0.608-0.696. The current study examined the gender and handle shape factors affecting grip strength based on the force measurements from various handle types, in terms of influence on different hand anthropometric indices.

  12. Carpal bone movements in gripping action of the giant panda (Ailuropoda melanoleuca).

    PubMed

    Endo, H; Sasaki, M; Hayashi, Y; Koie, H; Yamaya, Y; Kimura, J

    2001-02-01

    The movement of the carpal bones in gripping was clarified in the giant panda (Ailuropoda melanoleuca) by means of macroscopic anatomy, computed tomography (CT) and related 3-dimensional (3-D) volume rendering techniques. In the gripping action, 3-D CT images demonstrated that the radial and 4th carpal bones largely rotate or flex to the radial and ulnar sides respectively. This indicates that these carpal bones on both sides enable the panda to flex the palm from the forearm and to grasp objects by the manipulation mechanism that includes the radial sesamoid. In the macroscopic observations, we found that the smooth articulation surfaces are enlarged between the radial carpal and the radius on the radial side, and between the 4th and ulnar carpals on the ulnar side. The panda skilfully grasps using a double pincer-like apparatus with the huge radial sesamoid and accessory carpal.

  13. Grasping numbers: evidence for automatic influence of numerical magnitude on grip aperture.

    PubMed

    Namdar, Gal; Tzelgov, Joseph; Algom, Daniel; Ganel, Tzvi

    2014-06-01

    Previous research has shown that the fingers' aperture during grasp is affected by the numerical values of numbers embedded in the grasped objects: Numerically larger digits lead to larger grip apertures than do numerically smaller digits during the initial stages of the grasp. The relationship between numerical magnitude and visuomotor control has been taken to support the idea of a common underlying neural system mediating the processing of magnitude and the computation of object size for motor control. The purpose of the present study was to test whether the effect of magnitude on motor preparation is automatic. During grasping, we asked participants to attend to the colors of the digit while ignoring numerical magnitude. The results showed that numerical magnitude affected grip aperture during the initial stages of the grasp, even when magnitude information was irrelevant to the task at hand. These findings suggest that magnitude affects grasping preparation in an automatic fashion.

  14. Grip preference, dermatoglyphics, and hand use in captive chimpanzees (Pan troglodytes).

    PubMed

    Hopkins, William D; Russell, Jamie L; Hostetter, Autumn; Pilcher, Dawn; Dahl, Jeremy F

    2005-09-01

    This paper examined the association between grip type, hand use, and fingerprint patterns in a sample of captive chimpanzees. Grip type for simple reaching was assessed for the left and right hand and classified as thumb-index, middle-index, or single-digit responses. Fingerprint patterns were characterized as whorls, loops, or arches on each finger. The results indicated that chimpanzees exhibit significantly more thumb-index responses for the right compared to the left hand. In addition, thumb-index responses were more prevalent for subjects that had a whorl compared to a loop or arch on their thumb. The results suggest that fingerprint patterns are associated with individual differences in grasping type in chimpanzees as well as some variation in hand use.

  15. Effect of paddle grip on segmental fluid distribution in elite slalom paddlers.

    PubMed

    Bílý, Milan; Baláš, Jiří; Martin, Andrew John; Cochrane, Darryl; Coufalová, Klára; Süss, Vladimír

    2013-01-01

    Issues of high levels of muscular asymmetry have been associated with injury risk, and therefore have potential implications for decremental performance at the elite sport level. The aim of this current study was to assess the relationship between the segmental fluid distribution and the paddle grip in elite male and female slalom kayakers and canoeists. Eighty-four world-cup competitors (61 males and 23 females) took part in the study. Impedance analysis was used to assess segmental fluid asymmetry. The effect of paddle grip (loose/fixed hand in kayakers, lower/upper hand in canoeists), morphological dominance (dominant/non-dominant) and discipline (canoe/kayak) were evaluated by repeated measures ANOVA. The findings indicated a significant effect of paddle grip in canoeists on morphological asymmetry in upper limbs (arm of lower paddle hand mean fluid distribution 3.28, s=0.43 litres; arm of upper paddle hand mean fluid distribution 3.19, s=0.41 litres; P=0.000, [Formula: see text]=0.33). The sternmen demonstrated higher asymmetry between the arms of upper and lower paddle hand (mean 0.11, s=0.04 litres, P=0.000, [Formula: see text]=0.80) than the bowmen (mean 0.04, s=0.06 litres, P=0.015, [Formula: see text]=0.44) in double-canoes. Significant morphological asymmetry was found also in kayakers but the effect of paddle grip was not substantial. The use of segmental impedance analysis may be a suitable diagnostic tool for assessing morphological changes, which can be related to paddling training. Likewise muscular asymmetry is associated with injury risk; the evaluation of morphological changes during the training process may be considered by sport trainers and physical therapists.

  16. Quantifying Soldier Shooting Performance of the M4 Carbine with and without a Vertical Grip

    DTIC Science & Technology

    2015-01-01

    local Special Response Team (a local police force at Aberdeen Proving Ground). All 18 subjects fired both weapon conditions in the reflexive posture at...10-, 25-, and 50-m targets and aimed posture at 50-, 100-, and 150-m targets. For the reflexive posture, all subjects conducted 3 training trials with...differences in any of the weapon configurations (M4 with and without a vertical grip) in either the reflexive or aimed firing postures, suggesting that

  17. The impact of unilateral brain damage on anticipatory grip force scaling when lifting everyday objects.

    PubMed

    Eidenmüller, S; Randerath, J; Goldenberg, G; Li, Y; Hermsdörfer, J

    2014-08-01

    The scaling of our finger forces according to the properties of manipulated objects is an elementary prerequisite of skilled motor behavior. Lesions of the motor-dominant left brain may impair several aspects of motor planning. For example, limb-apraxia, a tool-use disorder after left brain damage is thought to be caused by deficient recall or integration of tool-use knowledge into an action plan. The aim of the present study was to investigate whether left brain damage affects anticipatory force scaling when lifting everyday objects. We examined 26 stroke patients with unilateral brain damage (16 with left brain damage, ten with right brain damage) and 21 healthy control subjects. Limb apraxia was assessed by testing pantomime of familiar tool-use and imitation of meaningless hand postures. Participants grasped and lifted twelve randomly presented everyday objects. Grip force was measured with help of sensors fixed on thumb, index and middle-finger. The maximum rate of grip force was determined to quantify the precision of anticipation of object properties. Regression analysis yielded clear deficits of anticipation in the group of patients with left brain damage, while the comparison of patient with right brain damage with their respective control group did not reveal comparable deficits. Lesion-analyses indicate that brain structures typically associated with a tool-use network in the left hemisphere play an essential role for anticipatory grip force scaling, especially the left inferior frontal gyrus (IFG) and the premotor cortex (PMC). Furthermore, significant correlations of impaired anticipation with limb apraxia scores suggest shared representations. However, the presence of dissociations, implicates also independent processes. Overall, our findings suggest that the left hemisphere is engaged in anticipatory grip force scaling for lifting everyday objects. The underlying neural substrate is not restricted to a single region or stream; instead it may rely on

  18. Influence of vision and posture on grip-lift task parameters in healthy adults.

    PubMed

    Dispa, Delphine; Tourbach, Catherine; Thonnard, Jean-Louis; Lejeune, Thierry

    2014-12-01

    The grip-lift task enables a quantitative assessment of grasping ability. Patients are regularly assessed in a supine position, which offers a different view of the grasped object from that in the sitting position. To our knowledge, no data are currently available on the influence of posture and vision on grip-lift task parameters. We therefore aimed to determine the effects of posture and vision on these parameters. Twenty-six healthy right-handed adults performed grip-lift tasks with a manipulandum that measured different temporal and dynamic parameters in four conditions: sitting eyes open, sitting blindfolded, lying down eyes open and lying down blindfolded. A repeated-measures analysis of variance with two factors (vision and position) showed that the absence of vision affected all the parameters measured. The lying down position increased the time between the first contact with the object and the modification of the vertical force as well as the delay between the first increase of the horizontal force and the increase of the vertical force. In addition, there was a lower adaption of the horizontal force, required to squeeze the object, to the vertical force. Finally, the interaction of position and vision was associated with significant differences in the delay between the contact of each digit with the object, the maximum horizontal force and the ratio between the horizontal and vertical force during a static holding period. Both position and vision appear to affect the grip-lift task. Consequently, sequential assessments should be performed in the same condition to obtain reliable data.

  19. Arm function after stroke. An evaluation of grip strength as a measure of recovery and a prognostic indicator.

    PubMed Central

    Sunderland, A; Tinson, D; Bradley, L; Hewer, R L

    1989-01-01

    The value of strength of voluntary grip as an indicator of recovery of arm function was assessed by testing 38 recent stroke patients using a sensitive electronic dynamometer, and comparing the results with those from five other arm movement and function tests (Motricity Index, Motor Club Assessment, Nine Hole Peg Test, and Frenchay Arm Test). This procedure allowed measurement of grip in a large proportion of patients, and strength correlated highly with performance on the other tests. Measuring grip over a six month follow up period was a sensitive method of charting intrinsic neurological recovery. The presence of voluntary grip at one month indicates that there will be some functional recovery at six months. PMID:2592969

  20. Immediate effects of forearm elastic and nonelastic taping on wrist flexor muscle and grip strength of normal adults

    PubMed Central

    Cha, Hyun-Gyu; Kim, Myoung-Kwon; Shin, Young-Jun

    2016-01-01

    [Purpose] The purpose of this study was to examine the effects of forearm elastic taping on grip and wrist flexor muscle strength. [Subjects and Methods] This was a single-blind, crossover study. This study selected 40 healthy subjects with no history of orthopedic disorders and was conducted after consent to participate was obtained. Grip and wrist flexor muscle strength of subjects were assessed by a handheld dynamometer and a Commander Muscle Tester, respectively, with forearm elastic taping or nonelastic taping. [Results] After application of forearm elastic taping, grip strength and wrist flexor muscle strength significantly increased compared with the nonelastic taping group. [Conclusion] Application of forearm elastic taping is considered to have positive effects on improving wrist and grip strength. PMID:27821932

  1. Observations During GRIP from HIRAD: Ocean Surface Wind Speed and Rain Rate

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Jones, L.; Ruf, C. S.; Uhlhorn, E. W.; Bailey, M. C.; Buckley, C. D.; Simmons, D. E.; Johnstone, S.; Peterson, A.; Schultz, L. A.; Biewas, S.; Johnson, J. W.; Shah, G.; Feingstein, D.; Cleveland, W. H.; Johnson, J.; Hood, R. E.

    2011-01-01

    HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA's GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be inferred. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. To the extent possible, comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

  2. Development and evaluation of an optimization-based model for power-grip posture prediction.

    PubMed

    Lee, Sang-Wook; Zhang, Xudong

    2005-08-01

    An optimization-based model for power-grip posture prediction was proposed. The model was based on the premise that the hand prehensile configuration in a power grip best conforms to the object shape. This premise was embodied by an optimization procedure that minimized the sum of distances from the finger joints to the object surface. The model was evaluated against data from an experiment that measured the grasp postures of 28 subjects having diverse anthropometry. The intra- and inter-person variabilities in grip postures were empirically assessed and used as benchmark values for model evaluation. The evaluation showed that the root-mean-square (RMS) values of angle differences between the predicted and measured postures had a 13.7 degrees grand mean (across all joints, subjects, and two cylindrical handles grasped), whereas the RMS values of the inter- and intra-person variabilities in measured postures had grand means of 13.0 degrees and 4.4 degrees , respectively. The model can be readily generalized to the prediction of postures in power-grasping objects of different shapes, and adapted for testing alternative prehensile strategies or performance criteria.

  3. Role of stag beetle jaw bending and torsion in grip on rivals

    PubMed Central

    Goyens, Jana; Dirckx, Joris; Piessen, Maxim; Aerts, Peter

    2016-01-01

    In aggressive battles, the extremely large male stag beetle jaws have to withstand strongly elevated bite forces. We found several adaptations of the male Cyclommatus metallifer jaw morphology for enhanced robustness that conspecific females lack. As a result, males improve their grip on opponents and they maintain their safety factor (5.2–7.2) at the same level as that of females (6.8), despite their strongly elevated bite muscle force (3.9 times stronger). Males have a higher second moment of area and torsion constant than females, owing to an enhanced cross-sectional area and shape. These parameters also increase faster with increasing bending moment towards the jaw base in males than in females. Male jaws are more bending resistant against the bite reaction force than against perpendicular forces (which remain lower in battles). Because of the triangular cross section of the male jaw base, it twists more easily than it bends. This torsional flexibility creates a safety system against overload that, at the same time, secures a firm grip on rivals. We found no structural mechanical function of the large teeth halfway along the male jaws. Therefore, it appears that the main purpose of these teeth is a further improvement of grip on rivals. PMID:26763329

  4. Role of stag beetle jaw bending and torsion in grip on rivals.

    PubMed

    Goyens, Jana; Dirckx, Joris; Piessen, Maxim; Aerts, Peter

    2016-01-01

    In aggressive battles, the extremely large male stag beetle jaws have to withstand strongly elevated bite forces. We found several adaptations of the male Cyclommatus metallifer jaw morphology for enhanced robustness that conspecific females lack. As a result, males improve their grip on opponents and they maintain their safety factor (5.2-7.2) at the same level as that of females (6.8), despite their strongly elevated bite muscle force (3.9 times stronger). Males have a higher second moment of area and torsion constant than females, owing to an enhanced cross-sectional area and shape. These parameters also increase faster with increasing bending moment towards the jaw base in males than in females. Male jaws are more bending resistant against the bite reaction force than against perpendicular forces (which remain lower in battles). Because of the triangular cross section of the male jaw base, it twists more easily than it bends. This torsional flexibility creates a safety system against overload that, at the same time, secures a firm grip on rivals. We found no structural mechanical function of the large teeth halfway along the male jaws. Therefore, it appears that the main purpose of these teeth is a further improvement of grip on rivals.

  5. The use of clamping grips and friction pads by tree frogs for climbing curved surfaces

    PubMed Central

    Ji, Aihong; Yuan, Shanshan; Hill, Iain; Wang, Huan; Barnes, W. Jon P.; Dai, Zhendong; Sitti, Metin

    2017-01-01

    Most studies on the adhesive mechanisms of climbing animals have addressed attachment against flat surfaces, yet many animals can climb highly curved surfaces, like twigs and small branches. Here we investigated whether tree frogs use a clamping grip by recording the ground reaction forces on a cylindrical object with either a smooth or anti-adhesive, rough surface. Furthermore, we measured the contact area of fore and hindlimbs against differently sized transparent cylinders and the forces of individual pads and subarticular tubercles in restrained animals. Our study revealed that frogs use friction and normal forces of roughly a similar magnitude for holding on to cylindrical objects. When challenged with climbing a non-adhesive surface, the compressive forces between opposite legs nearly doubled, indicating a stronger clamping grip. In contrast to climbing flat surfaces, frogs increased the contact area on all limbs by engaging not just adhesive pads but also subarticular tubercles on curved surfaces. Our force measurements showed that tubercles can withstand larger shear stresses than pads. SEM images of tubercles revealed a similar structure to that of toe pads including the presence of nanopillars, though channels surrounding epithelial cells were less pronounced. The tubercles' smaller size, proximal location on the toes and shallow cells make them probably less prone to buckling and thus ideal for gripping curved surfaces. PMID:28228509

  6. The use of clamping grips and friction pads by tree frogs for climbing curved surfaces.

    PubMed

    Endlein, Thomas; Ji, Aihong; Yuan, Shanshan; Hill, Iain; Wang, Huan; Barnes, W Jon P; Dai, Zhendong; Sitti, Metin

    2017-02-22

    Most studies on the adhesive mechanisms of climbing animals have addressed attachment against flat surfaces, yet many animals can climb highly curved surfaces, like twigs and small branches. Here we investigated whether tree frogs use a clamping grip by recording the ground reaction forces on a cylindrical object with either a smooth or anti-adhesive, rough surface. Furthermore, we measured the contact area of fore and hindlimbs against differently sized transparent cylinders and the forces of individual pads and subarticular tubercles in restrained animals. Our study revealed that frogs use friction and normal forces of roughly a similar magnitude for holding on to cylindrical objects. When challenged with climbing a non-adhesive surface, the compressive forces between opposite legs nearly doubled, indicating a stronger clamping grip. In contrast to climbing flat surfaces, frogs increased the contact area on all limbs by engaging not just adhesive pads but also subarticular tubercles on curved surfaces. Our force measurements showed that tubercles can withstand larger shear stresses than pads. SEM images of tubercles revealed a similar structure to that of toe pads including the presence of nanopillars, though channels surrounding epithelial cells were less pronounced. The tubercles' smaller size, proximal location on the toes and shallow cells make them probably less prone to buckling and thus ideal for gripping curved surfaces.

  7. Substrate diameter and compliance affect the gripping strategies and locomotor mode of climbing boa constrictors.

    PubMed

    Byrnes, Greg; Jayne, Bruce C

    2010-12-15

    Arboreal habitats pose unique challenges for locomotion as a result of their narrow cylindrical surfaces and discontinuities between branches. Decreased diameter of branches increases compliance, which can pose additional challenges, including effects on stability and energy damping. However, the combined effects of substrate diameter and compliance are poorly understood for any animal. We quantified performance, kinematics and substrate deformation while boa constrictors (Boa constrictor) climbed vertical ropes with three diameters (3, 6 and 9 mm) and four tensions (0.5, 1.0, 1.5 and 2.0 body weights). Mean forward velocity decreased significantly with both decreased diameter and increased compliance. Both diameter and compliance had numerous effects on locomotor kinematics, but diameter had larger and more pervasive effects than compliance. Locomotion on the largest diameter had a larger forward excursion per cycle, and the locomotor mode and gripping strategy differed from that on the smaller diameters. On larger diameters, snakes primarily applied opposing forces at the same location on the rope to grip. By contrast, on smaller diameters forces were applied in opposite directions at different locations along the rope, resulting in increased rope deformation. Although energy is likely to be lost during deformation, snakes might use increased surface deformation as a strategy to enhance their ability to grip.

  8. Effects of Tactile Sensitivity on Structural Variability of Digit Forces during Stable Precision Grip

    PubMed Central

    Wei, Na

    2016-01-01

    This study investigated the effects of fingertip tactile sensitivity on the structural variability of thumb and index finger forces during stable precision grip. Thirty right-handed healthy subjects participated in the experiment. Transient perturbation of tactile afferents was achieved by wrapping up the distal pads of the thumb or index finger with transparent polyethylene films. The time-dependent structure of each digit force and the variability of interdigit force correlation were examined by detrended fluctuation analysis (DFA) and detrended cross-correlation analysis (DCCA), respectively. Results showed that the tactile sensitivity affected αDFA of the vertical shear force Fx (F3,239 = 6.814, p < 0.001) and αDCCA of Fx (χ2 = 16.440, p < 0.001). No significant difference was observed in αDFA or αDCCA of the normal forces produced by the thumb or index finger. These results suggested that with blurred tactile sensory inputs the central nervous system might decrease the vertical shear force flexibility and increase the interdigit shear force coupling in order to guarantee a stable grip control of an object against gravity. This study shed light on the feedback and feed-forward strategies involved in digit force control and the role of SA-II afferent fibers in regulation of vertical shear force variability for precision grip. PMID:27847823

  9. Upper-limb kinematics and coordination of short grip and classic drives in field hockey.

    PubMed

    Bretigny, Perrine; Seifert, Ludovic; Leory, David; Chollet, Didier

    2008-08-01

    The aim of this study was to compare the upper-limb kinematics and coordination of the short grip and classic drives in field hockey. Ten elite female players participated in the experiment. The VICON system was used to record the displacement of markers placed on the stick and the players' joints during five short grip and five classic drives. Kinematic and coordination parameters were analyzed. The ball's velocity was recorded by a radar device that also served as the drive target. Kinematic differences were noted between the two drive conditions, with shorter duration and smaller overall amplitude in the short grip drive, explained by the shorter lever arm and the specific context in which it is used. No differences were noted for upper-limb coordination. In both types of stick holding, an interlimb dissociation was noted on the left side, whereas the right interlimb coordination was in phase. Moreover, the time lag increased in the disto-proximal direction, suggesting wrist uncocking before impact and the initiation of descent motion by the left shoulder. Mediolateral analysis confirmed these results: coordination of left-right limbs converged at the wrist but dissociated with more proximal joints (elbows and shoulders).

  10. Automatic motor cortex activation for natural as compared to awkward grips of a manipulable object.

    PubMed

    Petit, Leila S; Pegna, Alan J; Harris, Irina M; Michel, Christoph M

    2006-01-01

    It has been suggested that, relative to natural objects, man-made object representations in the brain are more specifically defined by functional properties that reflect how an object is used and/or what it is used for (Warrington and Shallice 1984). We recorded 123-channel event-related potentials (ERP) in healthy participants during a mental rotation task involving a manipulable (hammer) and a non-manipulable (church) object. Both stimuli had standard and mirror-image versions rotated in four different orientations, resulting for the manipulable object in some natural and some awkward grips. Using spatial cluster analysis, time periods were determined during which the ERP maps differed between stimulus conditions. Specific maps appeared for natural versus awkward grips with the manipulable object at a very early stage (60-116 ms) as well as during a later stage (180-280 ms). Source estimations derived from the topographic data indicated that during the second time window the left motor cortex was significantly activated in the case of natural grips. We argue that the motor programs that are semantically associated with the object are automatically activated when it is presented in graspable orientations.

  11. The size of the visual size cue used for programming manipulative forces during precision grip.

    PubMed

    Mon-Williams, M; Murray, A H

    2000-12-01

    We used a perturbation technique to quantify the contribution of visual size cues to the programming of target force when lifting an object. Our results indicate that the nervous system attaches a reasonable weight to visual size cues when programming the target grip force for a novel object. In a subsequent lift of the same object, however, the confidence attached to the visual size cue fell dramatically. It is not clear whether the decrease in the use of size information was accelerated by the presence of a cue conflict or whether the fall represents the normal shift towards the use of a memory-based representation for programming grip force. In a second experiment, we used the "size-weight illusion" to explore the relationship between the verbal report of an object's weight and the programming of the grip and load force. We found that erroneous motor programming (as indexed by a number of measures) was neither necessary nor sufficient for the size-weight illusion to occur. These findings call for a re-evaluation of a previous explanation for the size-weight illusion. We suggest that the illusion arises because the cognitive system attempts to rationalise the fact that objects of apparently equal density but different size feel as if they have the same weight.

  12. Associations between grip strength of parents and their 4 year old children: findings from the Southampton Women’s Survey

    PubMed Central

    Inskip, Hazel; Macdonald-Wallis, Corrie; Kapasi, Tasneem; Robinson, Siân; Godfrey, Keith; Cooper, Cyrus; Harvey, Nicholas; Sayer, Avan Aihie

    2013-01-01

    Summary Relationships between birthweight and grip strength throughout the lifecourse suggest that early influences on the growth and development of muscle are important for long-term muscle function. However, little is known about parental influences on children’s grip strength. We have explored this in the Southampton Women’s Survey, a prospective general population cohort study from before conception through childhood. Grip strength was measured using a Jamar handgrip dynamometer in the mother at 19 weeks’ gestation and her partner, and in the child at age four years. Pre-pregnancy heights and weights were measured in the mothers; reported weights and measured heights were available for the fathers. Complete data on parents and children were available for 444 trios. In univariate analyses, both parents’ grip strengths were significantly associated with that of the child (r=0.17, p<0.001 for mothers, r=0.15, p=0.002 for fathers). These correlations were similar to that between the grip strength of the mothers and the father (r=0.17, P<0.001). In the multivariate model, after adjustment for child’s height and physical activity, the correlations with the child’s grip strength were attenuated, being 0.10 (P=0.02) and 0.11 (P=0.01) for mothers’ and fathers’ grip strength respectively. The findings show that grip strength of both parents is associated with that of their child, indicating that heritable influences and the shared family environment influence the development of muscle strength. This contributes to our understanding of the role of heritable and environmental factors on early muscle growth and development, which are important for muscle function across the lifecourse. PMID:22150705

  13. Associations between grip strength of parents and their 4-year-old children: findings from the Southampton Women's Survey.

    PubMed

    Inskip, Hazel; Macdonald-Wallis, Corrie; Kapasi, Tasneem; Robinson, Siân; Godfrey, Keith; Cooper, Cyrus; Harvey, Nicholas; Sayer, Avan Aihie

    2012-01-01

    Relationships between birthweight and grip strength throughout the life course suggest that early influences on the growth and development of muscle are important for long-term muscle function. However, little is known about parental influences on children's grip strength. We have explored this in the Southampton Women's Survey, a prospective general population cohort study from before conception through childhood. Grip strength was measured using a Jamar handgrip dynamometer in the mother at 19 weeks' gestation and her partner, and in the child at age 4 years. Pre-pregnancy heights and weights were measured in the mothers; reported weights and measured heights were available for the fathers. Complete data on parents and children were available for 444 trios. In univariable analyses, both parents' grip strengths were significantly associated with that of the child (r = 0.17, P < 0.001 for mothers; r = 0.15, P = 0.002 for fathers). These correlations were similar to that between the grip strength of the mothers and the fathers (r = 0.17, P < 0.001). In the multivariable model, after adjustment for child's height and physical activity, the correlations with the child's grip strength were attenuated, being 0.10 (P = 0.02) and 0.11 (P = 0.01) for mothers' and fathers' grip strength respectively. The findings show that grip strength of each parent is associated with that of the child, indicating that heritable influences and the shared family environment influence the development of muscle strength. This contributes to our understanding of the role of heritable and environmental factors on early muscle growth and development, which are important for muscle function across the life course.

  14. Assessment of grip strength with the modified sphygmomanometer test: association between upper limb global strength and motor function

    PubMed Central

    Martins, Júlia C.; Aguiar, Larissa T.; Lara, Eliza M.; Teixeira-Salmela, Luci F.; Faria, Christina D. C. M.

    2015-01-01

    ABSTRACT Background: Grip strength, commonly evaluated with the handgrip dynamometer, is a good indicator of upper limb (UL) function in stroke subjects and may reflect the global strength deficits of the whole paretic UL. The Modified Sphygmomanometer Test (MST) also provides objective and adequate measures at low-cost. Objective: To assess whether grip strength values obtained by using the MST and those obtained by using a handgrip dynamometer would present similar correlations with the global strength and motor function of the paretic UL in subjects with stroke, both in the subacute and chronic phases. Method: Measures of grip strength (MST and handgrip dynamometer), UL global strength (MST and hand-held dynamometer), and UL motor function (Fugl-Meyer motor assessment scale) were obtained with 33 subacute and 44 chronic stroke subjects. Pearson and Spearman correlation coefficients were calculated and Stepwise multiple regression analyses were performed to investigate predictor variables of grip strength (α=0.05). Results: Significant correlations of similar magnitude were found between measures of global strength of the paretic UL and grip strength assessed with both the MST (0.66≤r≤0.78) and handgrip dynamometer (0.66≤r≤0.78) and between UL motor function and grip strength assessed with both the MST (0.50≤rs≤0.51) and hand-held dynamometer (0.50≤rs≤0.63) in subacute and chronic stroke subjects. Only global strength remained as a significant predictor variable of grip strength for the MST (0.43≤R2≤0.61) and for the handgrip dynamometer (0.44≤R2≤0.61) for both stroke subgroups. Conclusion: Grip strength assessed with the MST could be used to report paretic UL global strength. PMID:26647752

  15. The Association of Levels of and Decline in Grip Strength in Old Age with Trajectories of Life Course Occupational Position

    PubMed Central

    Fritzell, Johan; Hoffmann, Rasmus

    2016-01-01

    Background The study of the influence of life course occupational position (OP) on health in old age demands analysis of time patterns in both OP and health. We study associations between life course time patterns of OP and decline in grip strength in old age. Methods We analyze 5 waves from the Survey of Health Ageing and Retirement in Europe (n = 5108, ages 65–90). We use a pattern-mixture latent growth model to predict the level and decline in grip strength in old age by trajectory of life course OP. We extend and generalize the structured regression approach to establish the explanatory power of different life course models for both the level and decline of grip strength. Results Grip strength declined linearly by 0.70 kg (95% CI -0.74;-0.66) for men and 0.42 kg (95% CI -0.45;-0.39) for women per year. The level of men’s grip strength can best be explained by a critical period during midlife, with those exposed to low OP during this period having 1.67 kg (95% CI -2.33;-1.00) less grip strength. These differences remain constant over age. For women, no association between OP and levels of or decline in grip strength was found. Conclusions Men’s OP in midlife seems to be a critical period for the level of grip strength in old age. Inequalities remain constant over age. The integration of the structured regression approach and latent growth modelling offers new possibilities for life course epidemiology. PMID:27232696

  16. Solar Particle Acceleration and The Gamma Ray Imager/Polarimeter for Solar Flares (GRIPS) Instrument

    NASA Astrophysics Data System (ADS)

    Duncan, Nicole; Shih, A. Y.; Hurford, G. J.; Saint-Hilaire, P.; Bain, H.; Zoglauer, A.; Lin, R. P.; Boggs, S. E.

    2013-04-01

    Flares accelerate ions and relativistic electrons proportionally; the ratio of their fluences has been shown to remain constant over three orders of magnitude, a correlation that is independent of flare size. This evidence suggests that ion and electron populations are accelerated together, and possibly by similar mechanisms. In two of the best-observed flares of the last cycle, the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) satellite found the centroids of ion and relativistic electron associated emission to be significantly displaced from one another. This result is surprising; ions and electrons that are accelerated in the same region are thought to be transported along the same field lines, implying that they would enter the chromosphere together and have similar emission source locations. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS) instrument is designed to address particle transport questions by providing enhanced imaging, spectroscopy and polarimetry of gamma/HXR flare emissions 20 keV to > 10MeV). GRIPS’ key technological improvements over the current solar state of the art in HXR/gamma ray energies (RHESSI) include the use of three dimensional germanium detectors (3D-GeDs) and a single grid modulation collimator design, the multi-pitch rotating modulator (MPRM). The 3D-GeDs allow GRIPS to Compton track energy deposition within the crystal, providing significant background reduction and solar polarization measurements. Imaging will be primarily accomplished through the MPRM grid system. The single grid design provides quasi-continuous resolution from 12.5 - 162arcsecs with 2x the throughput of a dual grid imaging system like RHESSI. This spatial resolution will be capable of imaging the separate footpoints of many flare sizes. In comparison, RHESSI images with a minimum of 35arcsecs at HXR/gamma ray energies, making the footpoints resolvable in only the largest of flares. Here, we present a discussion of GRIPS science

  17. Phalanx force magnitude and trajectory deviation increased during power grip with an increased coefficient of friction at the hand-object interface.

    PubMed

    Enders, Leah R; Seo, Na Jin

    2011-05-17

    This study examined the effect of friction between the hand and grip surface on a person's grip strategy and force generation capacity. Twelve young healthy adults performed power grip exertions on an instrumented vertical cylinder with the maximum and 50% of maximum efforts (far above the grip force required to hold the cylinder), while normal and shear forces at each phalanx of all five fingers in the direction orthogonal to the gravity were recorded. The cylinder surface was varied for high-friction rubber and low-friction paper coverings. An increase in surface friction by replacing the paper covering with the rubber covering resulted in 4% greater mean phalanx normal force (perpendicular to the cylinder surface) and 22% greater mean phalanx shear force in either the proximal or distal direction of the digits (p<0.05; for both 50% and maximum grip efforts). Consequently, increased friction with the rubber surface compared to the paper surface was associated with a 20% increase in the angular deviation of the phalanx force from the direction normal to the cylinder surface (p<0.05). This study demonstrates that people significantly changed the magnitude and direction of phalanx forces depending on the surface they gripped. Such change in the grip strategy appears to help increase grip force generation capacity. This finding suggests that a seemingly simple power grip exertion involves sensory feedback-based motor control, and that people's power grip capacity may be reduced in cases of numbness, glove use, or injuries resulting in reduced sensation.

  18. Time-varying enhancement of human cortical excitability mediated by cutaneous inputs during precision grip.

    PubMed Central

    Johansson, R S; Lemon, R N; Westling, G

    1994-01-01

    1. We have investigated the afferent neurogram, muscular activity and mechanical responses while subjects restrained, with a precision grip, an object subjected to pulling loads directed away from the hand. At unpredictable times 'ramp-and-hold' loads of 1 N were delivered at a rate of ca 80 N s-1. The load ramp produced a sharp increase in multiunit activity recorded from cutaneous afferents of the median nerve. The first response in the EMG of distal hand muscles commenced at 51 +/- 2.4 ms (mean +/- S.D.); a further steep increase in activity began about 20 ms later, and this was associated with a marked augmentation of the grip force increase. 2. In four subjects, transcranial magnetic stimulation (TMS) was delivered to the contralateral motor cortex in 1000 out of a total of 1500 loading trials. The time of the stimulus was randomly selected to occur either at one of nine defined points (separated by 20 ms) before and after the computer command triggering the load force increase, or during steady periods of grip. 3. In most hand and arm muscles, there was a powerful facilitation of the short-latency EMG responses evoked by TMS delivered 40-140 ms after the load force command. The amplitudes of the largest responses (TMS delivered at 80-100 ms) were 850% higher on average than those observed when subjects gripped the unloaded object or when they restrained the statically loaded object. This large modulation was only obtained with stimulus intensities that were subthreshold in the relaxed subject. 4. The modulation was not simply a reflection of the time-varying level of motoneuronal activity during the loading trial. In most muscles, changes in the amplitude of the TMS-evoked responses were disproportionately larger than the corresponding modulation of the background EMG activity. At its maximum, the modulation in the TMS-evoked response was nearly 300% larger. Furthermore, the strength of the TMS-evoked responses did not strictly co-vary with amplitude of

  19. Bimanual force control strategies in chronic stroke: finger extension versus power grip.

    PubMed

    Lodha, Neha; Patten, Carolynn; Coombes, Stephen A; Cauraugh, James H

    2012-09-01

    Stroke leads to motor asymmetries in the flexor and extensor muscles of the hand. Typically, the strength deficits in the extensors are greater than the flexors. The impact of differential motor abilities of these muscle groups on the execution of bimanual force control tasks in individuals with stroke is unknown. The primary purpose of this study was to determine the influence of task constraints on visually guided bimanual force control in chronic stroke. Stroke survivors and age-matched individuals performed bimanual isometric contractions for 20s to match target submaximal force levels. Online visual feedback of the total force (sum of the forces produced by both hands) was provided. The task constraints were manipulated by (a) finger extension, and (b) finger flexion (power grip). Force asymmetry was indexed by the proportion of force contributed by the paretic hand to the total force. The stroke group demonstrated task-specific asymmetry in bimanual force control. Specifically, the paretic hand contributed less force than the non-paretic hand in finger extension whereas this relationship was reversed in power grip. Importantly, regardless of the nature of the task, reduction in motor impairments was associated with increased symmetry and coordination in bimanual tasks. Further, bimanual submaximal grip force control revealed asymmetry and coordination deficits that are not identified by investigating bimanual maximal force production alone. The motor control strategy adopted to optimize performance on bimanual tasks revealed the altered force production of the paretic hand due to the combined effect of extensor weakness and enhanced flexor bias following stroke. Bimanual asymmetries in stroke survivors highlight the need for identifying and treating the task-specific impairments for maximizing motor recovery post stroke.

  20. The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Bain, Hazel M.; Boggs, Steven E.; Zoglauer, Andreas C.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark S.; Takahashi, Tadayuki

    2012-09-01

    The balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungstenalloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 mm. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS is scheduled for a continental-US engineering test flight in fall 2013, followed by long or ultra-long duration balloon flights in Antarctica.

  1. Gloss, colour and grip: multifunctional epidermal cell shapes in bee- and bird-pollinated flowers.

    PubMed

    Papiorek, Sarah; Junker, Robert R; Lunau, Klaus

    2014-01-01

    Flowers bear the function of filters supporting the attraction of pollinators as well as the deterrence of floral antagonists. The effect of epidermal cell shape on the visual display and tactile properties of flowers has been evaluated only recently. In this study we quantitatively measured epidermal cell shape, gloss and spectral reflectance of flowers pollinated by either bees or birds testing three hypotheses: The first two hypotheses imply that bee-pollinated flowers might benefit from rough surfaces on visually-active parts produced by conical epidermal cells, as they may enhance the colour signal of flowers as well as the grip on flowers for bees. In contrast, bird-pollinated flowers might benefit from flat surfaces produced by flat epidermal cells, by avoiding frequent visitation from non-pollinating bees due to a reduced colour signal, as birds do not rely on specific colour parameters while foraging. Moreover, flat petal surfaces in bird-pollinated flowers may hamper grip for bees that do not touch anthers and stigmas while consuming nectar and thus, are considered as nectar thieves. Beside this, the third hypothesis implies that those flower parts which are vulnerable to nectar robbing of bee- as well as bird-pollinated flowers benefit from flat epidermal cells, hampering grip for nectar robbing bees. Our comparative data show in fact that conical epidermal cells are restricted to visually-active parts of bee-pollinated flowers, whereas robbing-sensitive parts of bee-pollinated as well as the entire floral surface of bird-pollinated flowers possess on average flat epidermal cells. However, direct correlations between epidermal cell shape and colour parameters have not been found. Our results together with published experimental studies show that epidermal cell shape as a largely neglected flower trait might act as an important feature in pollinator attraction and avoidance of antagonists, and thus may contribute to the partitioning of flower-visitors.

  2. Gloss, Colour and Grip: Multifunctional Epidermal Cell Shapes in Bee- and Bird-Pollinated Flowers

    PubMed Central

    Papiorek, Sarah; Junker, Robert R.; Lunau, Klaus

    2014-01-01

    Flowers bear the function of filters supporting the attraction of pollinators as well as the deterrence of floral antagonists. The effect of epidermal cell shape on the visual display and tactile properties of flowers has been evaluated only recently. In this study we quantitatively measured epidermal cell shape, gloss and spectral reflectance of flowers pollinated by either bees or birds testing three hypotheses: The first two hypotheses imply that bee-pollinated flowers might benefit from rough surfaces on visually-active parts produced by conical epidermal cells, as they may enhance the colour signal of flowers as well as the grip on flowers for bees. In contrast, bird-pollinated flowers might benefit from flat surfaces produced by flat epidermal cells, by avoiding frequent visitation from non-pollinating bees due to a reduced colour signal, as birds do not rely on specific colour parameters while foraging. Moreover, flat petal surfaces in bird-pollinated flowers may hamper grip for bees that do not touch anthers and stigmas while consuming nectar and thus, are considered as nectar thieves. Beside this, the third hypothesis implies that those flower parts which are vulnerable to nectar robbing of bee- as well as bird-pollinated flowers benefit from flat epidermal cells, hampering grip for nectar robbing bees. Our comparative data show in fact that conical epidermal cells are restricted to visually-active parts of bee-pollinated flowers, whereas robbing-sensitive parts of bee-pollinated as well as the entire floral surface of bird-pollinated flowers possess on average flat epidermal cells. However, direct correlations between epidermal cell shape and colour parameters have not been found. Our results together with published experimental studies show that epidermal cell shape as a largely neglected flower trait might act as an important feature in pollinator attraction and avoidance of antagonists, and thus may contribute to the partitioning of flower

  3. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Bain, Hazel M.; Boggs, Steven E.; Zoglauer, Andreas C.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark S.; Takahashi, Tadayuki

    2012-01-01

    The balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approximately 20 keV to greater than approximately 10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of less than 0.1 cubic millimeter. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-centimeter thick tungsten alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 millimeters. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS is scheduled for a continental-US engineering test flight in fall 2013, followed by long or ultra-long duration balloon flights in Antarctica.

  4. Updating the programming of a precision grip is a function of recent history of available feedback.

    PubMed

    Whitwell, Robert L; Goodale, Melvyn A

    2009-04-01

    In a recent study (Whitwell et al. in Exp Brain Res 185:111-119, 2008), we showed that the visuomotor system is "cognitively impenetrable" to the extent that explicit predictive knowledge of the availability of visual feedback on an upcoming trial fails to optimize grasping. The results suggested that the effects of trial history, rather than the anticipatory knowledge of the nature of an upcoming trial, plays the most significant role in how the availability of visual feedback is exploited by the visuomotor system when programming grip aperture (e.g., opening the hand wider when visual feedback is unavailable). Here, we provide direct evidence that trial history indeed plays a critical role in the programming of grip aperture. Twelve individuals grasped objects of three different sizes placed at one of two distances either with or without visual feedback of the hand and object (closed- or open-loop trials, respectively). Runs of four consecutive closed- or open-loop trials were interleaved with sequences of closed and open-loop trials that alternated back and forth from trial to trial. Peak grip aperture (PGA) decreased linearly with successive closed-loop trials and increased linearly with successive open-loop trials. We also compared PGA for trials that were preceded by a run of four consecutive closed- (or open-loop) trials with trials that were preceded by only one closed- (or open-loop) trial. This analysis indicated that consistency in the runs of closed- or open-loop trials significantly reduced the effect of the availability of feedback on grasping in the trial following the run. We conclude that while the margin of error observed in precision grasping is largely a function of the availability of visual feedback on the current trial, it is evidently also a function of the recent history of the availability of visual feedback on previous trials.

  5. Effects of grip force on median nerve deformation at different wrist angles

    PubMed Central

    Nakashima, Hiroki; Muraki, Satoshi

    2016-01-01

    The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p < 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p < 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately −25%; D1, −13%; D2, −12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (−29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve. PMID:27688983

  6. First flight of the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Saint-Hilaire, Pascal; Shih, Albert Y.; Duncan, Nicole; Bain, Hazel; Maruca, Bennett A.; Kelley, Nicole; Godbole, Niharika; Kaufmann, Pierre; Caspi, Amir; Sample, John; Hoberman, Jane; Mochizuki, Brent; Olson, Jerry; Boggs, Steven E.; Zoglauer, Andreas; Hurford, Gordon J.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark

    2016-05-01

    The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) high altitude balloon payload was successfully flown in January 2016 from Antarctica (Jan 19 to Jan 30).GRIPS provides a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma ray/hard X-ray emissions from ~20 keV to >~10 MeV. GRIPS’s goal is to address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of six 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 mm. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs, with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS was also equipped with active BGO shields, and three piggy-back instruments: a solar terahertz radiometer (Solar-T), a hard X-ray spectrometer (SMASH), and a sonic anemometer (TILDAE).We will present an overview of GRIPS's first flight, the performance of its instruments and subsystems, including the solar pointing and aspect systems, and

  7. Effect of Three Different Grip Angles on Physiological Parameters During Laboratory Handcycling Test in Able-Bodied Participants

    PubMed Central

    Abel, Thomas; Burkett, Brendan; Thees, Barbara; Schneider, Stefan; Askew, Christopher D.; Strüder, Heiko K.

    2015-01-01

    Introduction: Handcycling is a relatively new wheelchair sport that has gained increased popularity for people with lower limb disabilities. The aim of this study was to examine the effect of three different grip positions on physical parameters during handcycling in a laboratory setting. Methods: Twenty one able-bodied participants performed three maximum incremental handcycling tests until exhaustion, each with a different grip angle. The angle between the grip and the crank was randomly set at 90° (horizontal), 0° (vertical), or 10° (diagonal). The initial load was 20 W and increased by 20 W each 5 min. In addition, participants performed a 20 s maximum effort. Results: The relative peak functional performance (W/kg), peak heart rate (bpm), associated lactate concentrations (mmol/l) and peak oxygen uptake per kilogram body weight (ml.min−1.kg−1) for the different grip positions during the stage test were: (a) Horizontal: 1.43 ± 0.21 W/kg, 170.14 ± 12.81 bpm, 9.54 ± 1.93 mmol/l, 30.86 ± 4.57 ml/kg; (b) Vertical: 1.38 ± 0.20 W/kg, 171.81 ± 13.87 bpm, 9.91 ± 2.29 mmol/l, 29.75 ± 5.13 ml/kg; (c) Diagonal: 1.40 ± 0.22 W/kg, 169.19 ± 13.31 bpm, 9.34 ± 2.36 mmol/l, 29.39 ± 4.70 ml/kg. Statistically significant (p < 0.05) differences could only be found for lactate concentration between the vertical grip position and the other grips during submaximal handcycling. Conclusion: The orientation of three different grip angles made no difference to the peak load achieved during an incremental handcycling test and a 20 s maximum effort. At submaximal load, higher lactate concentrations were found when the vertical grip position was used, suggesting that this position may be less efficient than the alternative diagonal or horizontal grip positions. PMID:26635617

  8. Systematic mutational analysis of the active-site threonine of HIV-1 proteinase: rethinking the "fireman's grip" hypothesis.

    PubMed Central

    Strisovsky, K.; Tessmer, U.; Langner, J.; Konvalinka, J.; Kräusslich, H. G.

    2000-01-01

    Aspartic proteinases share a conserved network of hydrogen bonds (termed "fireman's grip"), which involves the hydroxyl groups of two threonine residues in the active site Asp-Thr-Gly triplets (Thr26 in the case of human immunodeficiency virus type 1 (HIV-1) PR). In the case of retroviral proteinases (PRs), which are active as symmetrical homodimers, these interactions occur at the dimer interface. For a systematic analysis of the "fireman's grip," Thr26 of HIV-1 PR was changed to either Ser, Cys, or Ala. The variant enzymes were tested for cleavage of HIV-1 derived peptide and polyprotein substrates. PR(T26S) and PR(T26C) showed similar or slightly reduced activity compared to wild-type HIV-1 PR, indicating that the sulfhydryl group of cysteine can substitute for the hydroxyl of the conserved threonine in this position. PR(T26A), which lacks the "fireman's grip" interaction, was virtually inactive and was monomeric in solution at conditions where wild-type PR exhibited a monomer-dimer equilibrium. All three mutations had little effect when introduced into only one chain of a linked dimer of HIV-1 PR. In this case, even changing both Thr residues to Ala yielded residual activity suggesting that the "fireman's grip" is not essential for activity but contributes significantly to dimer formation. Taken together, these results indicate that the "fireman's grip" is crucial for stabilization of the retroviral PR dimer and for overall stability of the enzyme. PMID:11045610

  9. The brain adjusts grip forces differently according to gravity and inertia: a parabolic flight experiment

    PubMed Central

    White, Olivier

    2015-01-01

    In everyday life, one of the most frequent activities involves accelerating and decelerating an object held in precision grip. In many contexts, humans scale and synchronize their grip force (GF), normal to the finger/object contact, in anticipation of the expected tangential load force (LF), resulting from the combination of the gravitational and the inertial forces. In many contexts, GF and LF are linearly coupled. A few studies have examined how we adjust the parameters–gain and offset–of this linear relationship. However, the question remains open as to how the brain adjusts GF regardless of whether LF is generated by different combinations of weight and inertia. Here, we designed conditions to generate equivalent magnitudes of LF by independently varying mass and movement frequency. In a control experiment, we directly manipulated gravity in parabolic flights, while other factors remained constant. We show with a simple computational approach that, to adjust GF, the brain is sensitive to how LFs are produced at the fingertips. This provides clear evidence that the analysis of the origin of LF is performed centrally, and not only at the periphery. PMID:25717293

  10. Effect of skin hydration on the dynamics of fingertip gripping contact.

    PubMed

    André, T; Lévesque, V; Hayward, V; Lefèvre, P; Thonnard, J-L

    2011-11-07

    The dynamics of fingertip contact manifest themselves in the complex skin movements observed during the transition from a stuck state to a fully developed slip. While investigating this transition, we found that it depended on skin hydration. To quantify this dependency, we asked subjects to slide their index fingertip on a glass surface while keeping the normal component of the interaction force constant with the help of visual feedback. Skin deformation inside the contact region was imaged with an optical apparatus that allowed us to quantify the relative sizes of the slipping and sticking regions. The ratio of the stuck skin area to the total contact area decreased linearly from 1 to 0 when the tangential force component increased from 0 to a maximum. The slope of this relationship was inversely correlated to the normal force component. The skin hydration level dramatically affected the dynamics of the contact encapsulated in the course of evolution from sticking to slipping. The specific effect was to reduce the tendency of a contact to slip, regardless of the variations of the coefficient of friction. Since grips were more unstable under dry skin conditions, our results suggest that the nervous system responds to dry skin by exaggerated grip forces that cannot be simply explained by a change in the coefficient of friction.

  11. Hurricane Imaging Radiometer Wind Speed and Rain Rate Retrievals during the 2010 GRIP Flight Experiment

    NASA Technical Reports Server (NTRS)

    Sahawneh, Saleem; Farrar, Spencer; Johnson, James; Jones, W. Linwood; Roberts, Jason; Biswas, Sayak; Cecil, Daniel

    2014-01-01

    Microwave remote sensing observations of hurricanes, from NOAA and USAF hurricane surveillance aircraft, provide vital data for hurricane research and operations, for forecasting the intensity and track of tropical storms. The current operational standard for hurricane wind speed and rain rate measurements is the Stepped Frequency Microwave Radiometer (SFMR), which is a nadir viewing passive microwave airborne remote sensor. The Hurricane Imaging Radiometer, HIRAD, will extend the nadir viewing SFMR capability to provide wide swath images of wind speed and rain rate, while flying on a high altitude aircraft. HIRAD was first flown in the Genesis and Rapid Intensification Processes, GRIP, NASA hurricane field experiment in 2010. This paper reports on geophysical retrieval results and provides hurricane images from GRIP flights. An overview of the HIRAD instrument and the radiative transfer theory based, wind speed/rain rate retrieval algorithm is included. Results are presented for hurricane wind speed and rain rate for Earl and Karl, with comparison to collocated SFMR retrievals and WP3D Fuselage Radar images for validation purposes.

  12. Segregated and overlapping neural circuits exist for the production of static and dynamic precision grip force.

    PubMed

    Neely, Kristina A; Coombes, Stephen A; Planetta, Peggy J; Vaillancourt, David E

    2013-03-01

    A central topic in sensorimotor neuroscience is the static-dynamic dichotomy that exists throughout the nervous system. Previous work examining motor unit synchronization reports that the activation strategy and timing of motor units differ for static and dynamic tasks. However, it remains unclear whether segregated or overlapping blood-oxygen-level-dependent (BOLD) activity exists in the brain for static and dynamic motor control. This study compared the neural circuits associated with the production of static force to those associated with the production of dynamic force pulses. To that end, healthy young adults (n = 17) completed static and dynamic precision grip force tasks during functional magnetic resonance imaging (fMRI). Both tasks activated core regions within the visuomotor network, including primary and sensory motor cortices, premotor cortices, multiple visual areas, putamen, and cerebellum. Static force was associated with unique activity in a right-lateralized cortical network including inferior parietal lobe, ventral premotor cortex, and dorsolateral prefrontal cortex. In contrast, dynamic force was associated with unique activity in left-lateralized and midline cortical regions, including supplementary motor area, superior parietal lobe, fusiform gyrus, and visual area V3. These findings provide the first neuroimaging evidence supporting a lateralized pattern of brain activity for the production of static and dynamic precision grip force.

  13. MusicGlove: motivating and quantifying hand movement rehabilitation by using functional grips to play music.

    PubMed

    Friedman, Nizan; Chan, Vicky; Zondervan, Danny; Bachman, Mark; Reinkensmeyer, David J

    2011-01-01

    People with stroke typically must perform much of their hand exercise at home without professional assistance as soon as two weeks after the stroke. Without feedback and encouragement, individuals often lose motivation to practice using the affected hand, and this disuse contributes to further declines in hand function. We developed the MusicGlove as a way to facilitate and motivate at home practice of hand movement. This low-cost device uses music as an interactive and motivating medium to guide hand exercise and to quantitatively assess hand movement recovery. It requires the user to practice functional movements, including pincer grip, key-pinch grip, and finger-thumb opposition, by using those movements to play different musical notes, played along to songs displayed by an interactive computer game. We report here the design of the glove and the results of a single-session experiment with 10 participants with chronic stroke. We found that the glove is well suited for use by people with an impairment level quantified by a Box and Blocks score of at least around 7; that the glove can be used to obtain a measure of hand dexterity (% of notes hit) that correlates strongly with the Box and Blocks score; and that the incorporation of music into training significantly improved both objective measures of hand motor performance and self-ratings of motivation for training in the single session.

  14. Electric Field Measurements During the Genesis and Rapid Intensification Processes (GRIP) Field Program

    NASA Technical Reports Server (NTRS)

    Bateman, Monte G.; Blakeslee, Richard J.; Mach, Douglas M.

    2010-01-01

    During the Genesis and Rapid Intensification Processes (GRIP) field program, a system of 6 electric field mills was flown on one of NASA's Global Hawk aircraft. We placed several mills on the aircraft to enable us to measure the vector electric field. We created a distributed, ethernet-connected system so that each sensor has its own embedded Linux system, complete with web server. This makes our current generation system fully "sensor web enabled." The Global Hawk has several unique qualities, but relevant to quality storm electric field measurements are high altitude (20 km) and long duration (20-30 hours) flights. There are several aircraft participating in the GRIP program, and coordinated measurements are happening. Lightning and electric field measurements will be used to study the relationships between lightning and other storm characteristics. It has been long understood that lightning can be used as a marker for strong convective activity. Past research and field programs suggest that lightning flash rate may serve as an indicator and precursor for rapid intensification change in tropical cyclones and hurricanes. We have the opportunity to sample hurricanes for many hours at a time and observe intensification (or de-intensification) periods. The electrical properties of hurricanes during such periods are not well known. American

  15. The effect of vibration exposure during haul truck operation on grip strength, touch sensation, and balance.

    PubMed

    Pollard, Jonisha; Porter, William; Mayton, Alan; Xu, Xueyan; Weston, Eric

    2017-01-01

    Falls from mobile equipment are reported at surface mine quarry operations each year in considerable numbers. Research shows that a preponderance of falls occur while getting on/off mobile equipment. Contributing factors to the risk of falls include the usage of ladders, exiting onto a slippery surface, and foot or hand slippage. Balance issues may also contribute to fall risks for mobile equipment operators who are exposed to whole-body vibration (WBV). For this reason, the National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research conducted a study at four participating mine sites with seven haul truck operators. The purpose was to ascertain whether WBV and hand-arm vibration (HAV) exposures for quarry haul truck operators were linked to short-term decreases in performance in relation to postural stability, touch sensation threshold, and grip strength that are of crucial importance when getting on/off the trucks. WBV measures of frequency-weighted RMS accelerations (wRMS) and vibration dose value (VDV), when compared to the ISO/ANSI standards, were mostly below levels identified for the Health Guidance Caution Zone (HGCZ), although there were instances where the levels were within and above the specified Exposure Action Value. Comparably, all mean HAV levels, when compared to the ISO/ANSI standards, were below the HGCZ. For the existing conditions and equipment, no significant correlation could be identified between the WBV, HAV, postural stability, touch sensation threshold, and grip strength measures taken during this study.

  16. Gripping Mechanisms for Microgravity and Extreme Terrain and Vertical Climbing Micro Ground Vehicle

    NASA Technical Reports Server (NTRS)

    McKenzie, Clifford; Parness, Aaron

    2011-01-01

    Asteroids and comets may provide insight into the origins of our solar system and the precursors to life on our planet. Near Earth objects offer an accessible target of opportunity, but are small and lack the gravity necessary for conventional wheeled travel. Therefore, it is necessary to develop alternative methods for maneuvering in these environments. This project researched and developed a method for gripping rock surfaces. Work has been completed on the design and prototyping of several possible hooked gripping mechanisms. Future work includes quantitative testing, downselection to a final design, and attachment to the robotic platform, Lemur IIb. A second project focuses on the development of a 100g, crash-proof robot capable of climbing vertical surfaces using a novel silicone adhesive. Capable of carrying video/audio payloads the robot may serve as a surveillance tool for the Department of Defense or as a method of pre-flight spacecraft inspections. A specialized track was developed to provide the specific loading conditions necessary for proper engagement of the adhesive. Both of these projects rely heavily on the shape deposition manufacturing process, being researched at JPL, and 3D printing.

  17. Is the coefficient of variation a valid measure for detecting sincerity of effort of grip strength?

    PubMed

    Shechtman, Orit

    1999-01-01

    The wide use of the coefficient of variation in detecting sincerity of effort is puzzling since existing research findings regarding its effectiveness are contradictory. The lack of empirical support in the literature raises the question of whether or not the coefficient of variation is a valid measure for detecting sincerity of effort. Many clinicians, especially those who use a computer software to calculate the coefficient of variation, may not understand how the coefficient of variation is derived and what it is based on. The coefficient of variation is a measure of relative variability and would be used correctly only if the average and the standard deviation of grip strength trials increased proportionally. This case study, however, demonstrated that the average and standard deviation of grip strength are independent. Thus, the coefficient of variation is not a valid measure of sincerity of effort. In addition, this study indicated that the coefficient of variation may be inflated in individuals after carpal tunnel release surgery. The author, therefore, cautions clinicians against the use of the coefficient of variation as a measure of sincerity of effort especially in injured individuals with compromised hand strength.

  18. The administration and interpretation of the rapid exchange grip test: a national survey.

    PubMed

    Shechtman, Orit; Goodall, Sara K

    2008-01-01

    The purpose of the present study was to determine if the administration and interpretation of the rapid exchange grip (REG) test vary among hand therapists nationally. The REG is used to determine sincerity of effort of grip strength. There are inconsistencies in the literature regarding the administration and interpretation of the REG, as various studies use different testing protocols and diverse interpretation criteria for what constitutes a sincere effort. As a result, we expected to find a lack of standardization in the administration and interpretation of the REG in clinical practice. We conducted a random nationwide survey of 200 hand therapists. The questionnaire items regarding the administration of the REG included patient position, test instructions, handle settings, handling of the dynamometer, hand switch rate, number of repetitions, and techniques used to record the score. The items for the interpretation of the REG involved questions regarding comparative tests. We found that the REG test lacks standardized administration protocols and interpretation criteria among therapists nationwide. The lack of standardization is likely to affect the reliability and validity of the REG and to hinder the therapist's ability to accurately report its outcomes. The implications of lack of standardization in assessment techniques to the profession are discussed.

  19. Effect of skin hydration on the dynamics of fingertip gripping contact

    PubMed Central

    André, T.; Lévesque, V.; Hayward, V.; Lefèvre, P.; Thonnard, J.-L.

    2011-01-01

    The dynamics of fingertip contact manifest themselves in the complex skin movements observed during the transition from a stuck state to a fully developed slip. While investigating this transition, we found that it depended on skin hydration. To quantify this dependency, we asked subjects to slide their index fingertip on a glass surface while keeping the normal component of the interaction force constant with the help of visual feedback. Skin deformation inside the contact region was imaged with an optical apparatus that allowed us to quantify the relative sizes of the slipping and sticking regions. The ratio of the stuck skin area to the total contact area decreased linearly from 1 to 0 when the tangential force component increased from 0 to a maximum. The slope of this relationship was inversely correlated to the normal force component. The skin hydration level dramatically affected the dynamics of the contact encapsulated in the course of evolution from sticking to slipping. The specific effect was to reduce the tendency of a contact to slip, regardless of the variations of the coefficient of friction. Since grips were more unstable under dry skin conditions, our results suggest that the nervous system responds to dry skin by exaggerated grip forces that cannot be simply explained by a change in the coefficient of friction. PMID:21490002

  20. Positive force feedback in development of substrate grip in the stick insect tarsus.

    PubMed

    Zill, Sasha N; Chaudhry, Sumaiya; Exter, Annelie; Büschges, Ansgar; Schmitz, Josef

    2014-09-01

    The mechanics of substrate adhesion has recently been intensively studied in insects but less is known about the sensorimotor control of substrate engagement. We characterized the responses and motor effects of tarsal campaniform sensilla in stick insects to understand how sensory signals of force could contribute to substrate grip. The tarsi consist of a chain of segments linked by highly flexible articulations. Morphological studies showed that one to four campaniform sensilla are located on the distal end of each segment. Activities of the receptors were recorded neurographically and sensilla were identified by stimulation and ablation of their cuticular caps. Responses were characterized to bending forces and axial loads, muscle contractions and to forces applied to the retractor apodeme (tendon). The tarsal sensilla effectively encoded both the rate and amplitude of loads and muscle forces, but only when movement was resisted. Mechanical stimulation of the receptors produced activation of motor neurons in the retractor unguis and tibial flexor muscles. These findings indicate that campaniform sensilla can provide information about the effectiveness of the leg muscles in generating substrate adherence. They can also produce positive force feedback that could contribute to the development of substrate grip and stabilization of the tarsal chain.

  1. Muscular forearm activation in hand-grip tasks with superimposition of mechanical vibrations.

    PubMed

    Fattorini, L; Tirabasso, A; Lunghi, A; Di Giovanni, R; Sacco, F; Marchetti, E

    2016-02-01

    The purpose of this paper is to evaluate the muscular activation of the forearm, with or without vibration stimuli at different frequencies while performing a grip tasks of 45s at various level of exerted force. In 16 individuals, 9 females and 7 males, the surface electromyogram (EMG) of extensor carpi radialis longus and the flexor carpi ulnari muscles were assessed. At a short latency from onset EMG, RMS and the level of MU synchronization were assessed to evaluate the muscular adaptations. Whilst a trend of decay of EMG Median frequency (MDFd) was employed as an index of muscular fatigue. Muscular tasks consists of the grip of an instrumented handle at a force level of 20%, 30%, 40%, 60% of the maximum voluntary force. Vibration was supplied by a shaker to the hand in mono-frequential waves at 20, 30, 33 and 40Hz. In relation to EMG, RMS and MU synchronization, the muscular activation does not seem to change with the superimposition of the mechanical vibrations, on the contrary a lower MDFd was observed at 33Hz than in absence of vibration. This suggests an early muscular fatigue induced by vibration due to the fact that 33Hz is a resonance frequency for the hand-arm system.

  2. Equivalent comfort contours for vertical vibration of steering wheels: effect of vibration magnitude, grip force, and hand position.

    PubMed

    Morioka, Miyuki; Griffin, Michael J

    2009-09-01

    Vehicle drivers receive tactile feedback from steering-wheel vibration that depends on the frequency and magnitude of the vibration. From an experiment with 12 subjects, equivalent comfort contours were determined for vertical vibration of the hands at two positions with three grip forces. The perceived intensity of the vibration was determined using the method of magnitude estimation over a range of frequencies (4-250 Hz) and magnitudes (0.1-1.58 ms(-2) r.m.s.). Absolute thresholds for vibration perception were also determined for the two hand positions over the same frequency range. The shapes of the comfort contours were strongly dependent on vibration magnitude and also influenced by grip force, indicating that the appropriate frequency weighting depends on vibration magnitude and grip force. There was only a small effect of hand position. The findings are explained by characteristics of the Pacinian and non-Pacinian tactile channels in the glabrous skin of the hand.

  3. Effect of the Mandibular Orthopedic Repositioning Appliance (MORA) on Forearm Muscle Activation and Grasping Power during Pinch and Hook Grip

    PubMed Central

    Lee, Sang-Yeol; Park, Yi-Jeong; Park, Hye-Min; Bae, Hae-Jin; Yu, Min-Ji; Choi, Hee-Won; Hwang, Na-Young

    2014-01-01

    [Purpose] This study verified the changes in muscle activities and grasping power during maximal isometric exercise of the forearm and masseter muscle with and without a mandibular orthopedic repositioning appliance (MORA). It also offers basic data for defining the correlation of function of hand with mouth. [Methods] EMG was used to measure masticatory muscle, flexor bundle and extensor bundle activities with or without MORA while subjects performed the hook grip and pinch grip. The measuring tool used for measuring grip strength was the same as that used for measuring pinch and hook strength. The subjects were 28 healthy young adults. [Result] Muscle activity and grasping power significantly increased when wearing the MORA. [Conclusion] The result indicates that wearing MORA can increase muscle activity and grasping power of forearm and masseter muscle. We think wearing MORA might help improve the function of the forearm because it activates the function of the masseter. PMID:24648630

  4. The coefficient of variation as a measure of sincerity of effort of grip strength, Part I: the statistical principle.

    PubMed

    Shechtman, O

    2001-01-01

    The coefficient of variation (CV) is a widely used measure of sincerity of effort of grip strength despite contradictory research findings and lack of empirical support in the literature. The purpose of this study was to investigate whether the CV is an appropriate measure of sincerity of effort. One hundred forty-six uninjured volunteers underwent a series of grip strength tests. The mean, standard deviation (SD), and CV of repeated strength trials were calculated, and paired comparisons were conducted between maximal and submaximal efforts. While the mean of maximal trials was significantly greater, there were no differences in SD between maximal and submaximal trials. Therefore, the increased CV associated with submaximal effort was an artifact of reduced torque rather than an indicator of a true increase in variability. Consequently, the CV is not an appropriate measure of sincerity of effort of grip strength.

  5. Grip and Pinch Strength in Healthy Subjects and Patients with Primary Osteoarthritis of the Hand: A Reproducibility Study

    PubMed Central

    Ziv, Efrat; Patish, Hagar; Dvir, Zeevi

    2008-01-01

    Grip, Key Pinch (KP), 3 Point Pinch (3PP) and 2 Point Pinch (2PP) strengths were measured twice weekly in 32 women with primary osteoarthritis of the hand (POAH) and 25 healthy women. Reproducibility was assessed by standard error of measurement (SEM) and the coefficient of variation (CV). Cutoff values for significant improvement or deterioration were determined and expressed, respectively, as either the smallest detectable difference (SDD) or critical difference (CD). The SDD and CD of grip and pinch strengths were higher in POAH patients than in the healthy group. Among the pinch tests the 2PP findings were least reproducible. The relatively high SDD and CD scores indicate that improvement may be detected only in patients with moderate to severe weakness of grip and pinch. Furthermore, in POAH patients, diagnosing strength changes using the 2PP test is invalid due to low reproducibility. PMID:19478930

  6. Modified forelimb grip strength test detects aging-associated physiological decline in skeletal muscle function in male mice.

    PubMed

    Takeshita, Hikari; Yamamoto, Koichi; Nozato, Satoko; Inagaki, Tadakatsu; Tsuchimochi, Hirotsugu; Shirai, Mikiyasu; Yamamoto, Ryohei; Imaizumi, Yuki; Hongyo, Kazuhiro; Yokoyama, Serina; Takeda, Masao; Oguro, Ryosuke; Takami, Yoichi; Itoh, Norihisa; Takeya, Yasushi; Sugimoto, Ken; Fukada, So-Ichiro; Rakugi, Hiromi

    2017-02-08

    The conventional forelimb grip strength test is a widely used method to assess skeletal muscle function in rodents; in this study, we modified this method to improve its variability and consistency. The modified test had lower variability among trials and days than the conventional test in young C57BL6 mice, especially by improving the variabilities in male. The modified test was more sensitive than the conventional test to detect a difference in motor function between female and male mice, or between young and old male mice. When the modified test was performed on male mice during the aging process, reduction of grip strength manifested between 18 and 24 months of age at the group level and at the individual level. The modified test was similar to the conventional test in detecting skeletal muscle dysfunction in young male dystrophic mice. Thus, the modified forelimb grip strength test, with its improved validity and reliability may be an ideal substitute for the conventional method.

  7. Haptic feedback enhances grip force control of sEMG-controlled prosthetic hands in targeted reinnervation amputees.

    PubMed

    Kim, Keehoon; Colgate, J Edward

    2012-11-01

    In this study, we hypothesized that haptic feedback would enhance grip force control of surface electromyography (sEMG)-controlled prosthetic hands for targeted reinnervation (TR) amputees. A new miniature haptic device, a tactor, that can deliver touch, pressure, shear, and temperature sensation, allows modality-matching haptic feedback. TR surgery that creates sensory regions on the patient's skin that refer to the surface of the missing limb allows somatotopic-matching haptic feedback. This paper evaluates the hypothesis via an sEMG-controlled virtual prosthetic arm operated by TR amputees under diverse haptic feedback conditions. The results indicate that the grip force control is significantly enhanced via the haptic feedback. However, the simultaneous display of two haptic channels (pressure and shear) does not enhance, but instead degrades, grip force control.

  8. Influence of finger amputation on grip strength and objectively measured hand function: a descriptive cross-sectional study.

    PubMed

    Kuret, Zala; Burger, Helena; Vidmar, Gaj

    2015-06-01

    Finger amputations are common and hands are essential for functioning, but studies on factors influencing functioning after finger amputation are lacking. Therefore, we aimed to explore the influence of the number and level of amputated fingers on hand function and grip strength. A prospective descriptive cross-sectional study involving 69 patients with partial or complete amputation of one or more fingers of one hand was carried out. The function of both hands was assessed using the Southampton Hand Assessment Procedure test; grip strength was measured in 42 patients. We confirmed that finger amputation worsens hand function (especially tripod and tip pinch) and reduces grip strength, whereby the extent of the worsening depends on amputation type - it is the smallest after thumb amputation and the largest after amputation of the index finger and fingers III-V. However, because of the variety of amputation types, we recommend that future studies either involve very large samples or focus on specific amputations.

  9. Modeling the Maturation of Grip Selection Planning and Action Representation: Insights from Typical and Atypical Motor Development

    PubMed Central

    Fuelscher, Ian; Williams, Jacqueline; Wilmut, Kate; Enticott, Peter G.; Hyde, Christian

    2016-01-01

    We investigated the purported association between developmental changes in grip selection planning and improvements in an individual’s capacity to represent action at an internal level [i.e., motor imagery (MI)]. Participants were groups of healthy children aged 6–7 years and 8–12 years respectively, while a group of adolescents (13–17 years) and adults (18–34 years) allowed for consideration of childhood development in the broader context of motor maturation. A group of children aged 8–12 years with probable DCD (pDCD) was included as a reference group for atypical motor development. Participants’ proficiency to generate and/or engage internal action representations was inferred from performance on the hand rotation task, a well-validated measure of MI. A grip selection task designed to elicit the end-state comfort (ESC) effect provided a window into the integrity of grip selection planning. Consistent with earlier accounts, the efficiency of grip selection planning followed a non-linear developmental progression in neurotypical individuals. As expected, analysis confirmed that these developmental improvements were predicted by an increased capacity to generate and/or engage internal action representations. The profile of this association remained stable throughout the (typical) developmental spectrum. These findings are consistent with computational accounts of action planning that argue that internal action representations are associated with the expression and development of grip selection planning across typical development. However, no such association was found for our sample of children with pDCD, suggesting that individuals with atypical motor skill may adopt an alternative, sub-optimal strategy to plan their grip selection compared to their same-age control peers. PMID:26903915

  10. Modeling the Maturation of Grip Selection Planning and Action Representation: Insights from Typical and Atypical Motor Development.

    PubMed

    Fuelscher, Ian; Williams, Jacqueline; Wilmut, Kate; Enticott, Peter G; Hyde, Christian

    2016-01-01

    We investigated the purported association between developmental changes in grip selection planning and improvements in an individual's capacity to represent action at an internal level [i.e., motor imagery (MI)]. Participants were groups of healthy children aged 6-7 years and 8-12 years respectively, while a group of adolescents (13-17 years) and adults (18-34 years) allowed for consideration of childhood development in the broader context of motor maturation. A group of children aged 8-12 years with probable DCD (pDCD) was included as a reference group for atypical motor development. Participants' proficiency to generate and/or engage internal action representations was inferred from performance on the hand rotation task, a well-validated measure of MI. A grip selection task designed to elicit the end-state comfort (ESC) effect provided a window into the integrity of grip selection planning. Consistent with earlier accounts, the efficiency of grip selection planning followed a non-linear developmental progression in neurotypical individuals. As expected, analysis confirmed that these developmental improvements were predicted by an increased capacity to generate and/or engage internal action representations. The profile of this association remained stable throughout the (typical) developmental spectrum. These findings are consistent with computational accounts of action planning that argue that internal action representations are associated with the expression and development of grip selection planning across typical development. However, no such association was found for our sample of children with pDCD, suggesting that individuals with atypical motor skill may adopt an alternative, sub-optimal strategy to plan their grip selection compared to their same-age control peers.

  11. Hard X-ray imaging survey of the Galactic plane with the Caltech gamma-ray imaging payload GRIP-2

    NASA Technical Reports Server (NTRS)

    Corbel, S.; Cook, W. R.; Harrison, F. A.; Prince, T. A.; Schindler, S. M.; Wang, S.

    1997-01-01

    In a two-day balloon flight during October 1995, the Caltech coded aperture gamma ray imaging payload (GRIP-2) imaged various fields in the Galactic plane and center in the 25 to 600 keV energy band. The large phoswich detector, the 15 deg field of view, the 30 arcmin angular resolution and 6 arcmin point source localization capability of GRIP-2 provides the possibility of surveying the accreting binary population of the Galaxy at high energy. The instrument is described and preliminary imaging results are reported on. The capabilities of this instrument for hard X-ray/gamma ray imaging are demonstrated.

  12. Latest Progress on the Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Lin, R. P.; Hurford, G. J.; Duncan, N. A.; Saint-Hilaire, P.; Smith, D. M.; Tajima, H.; Amman, M.; Grips Team

    2011-12-01

    We present the latest progress on building the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument, including testing and calibration of the detectors and development of the imaging and aspect systems. A continental-US test flight is slated for fall 2012. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 mm^3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  13. Latest Progress on the Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Smith, David Miles; Tajima, Hiroyasu; Amman, Mark

    2011-01-01

    We present the latest progress on building the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument, including testing and calibration of the detectors and development of the imaging and aspect systems. A continental-US test flight is slated for fall 2012. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approx.20. keV to > approx.10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 cu mm. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that ha-.e been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  14. The Gamma-Ray Imager/Polarimeter For Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2009-01-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from 20 keV to > 10 MeV. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM) situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), using a similar technique to rotating-modulation-collimator imaging used on missions such as RHESSI but now taking advantage of the position sensitivity of the spectrometer. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer). A balloon platform for this instrument minimizes atmospheric attenuation and accommodates its weight and size, and long-duration balloon flights (LDBFs) from Antarctica allow for month-long uninterrupted observations of the Sun to continuously observe active regions and to maximize the chance of capturing a gamma-ray flare. A continental-US test flight is slated for 2012 with the eventual goal of Antarctic LDBFs of the completed instrument. In addition to the direct science return from these flights, GRIPS will prove these technologies for a future space

  15. The Gamma-Ray Imager/Polarimeter For Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2009-05-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from 20 keV to > 10 MeV. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM) situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), using a similar technique to rotating-modulation-collimator imaging used on missions such as RHESSI but now taking advantage of the position sensitivity of the spectrometer. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer). A balloon platform for this instrument minimizes atmospheric attenuation and accommodates its weight and size, and long-duration balloon flights (LDBFs) from Antarctica allow for month-long uninterrupted observations of the Sun to continuously observe active regions and to maximize the chance of capturing a gamma-ray flare. A continental-US test flight is slated for 2012 with the eventual goal of Antarctic LDBFs of the completed instrument. In addition to the direct science return from these flights, GRIPS will prove these technologies for a future space

  16. Effect of blocking tactile information from the fingertips on adaptation and execution of grip forces to friction at the grasping surface.

    PubMed

    Bilaloglu, Seda; Lu, Ying; Geller, Daniel; Rizzo, John Ross; Aluru, Viswanath; Gardner, Esther P; Raghavan, Preeti

    2016-03-01

    Adaptation of fingertip forces to friction at the grasping surface is necessary to prevent use of inadequate or excessive grip forces. In the current study we investigated the effect of blocking tactile information from the fingertips noninvasively on the adaptation and efficiency of grip forces to surface friction during precision grasp. Ten neurologically intact subjects grasped and lifted an instrumented grip device with 18 different frictional surfaces under three conditions: with bare hands or with a thin layer of plastic (Tegaderm) or an additional layer of foam affixed to the fingertips. The coefficient of friction at the finger-object interface of each surface was obtained for each subject with bare hands and Tegaderm by measuring the slip ratio (grip force/load force) at the moment of slip. We found that the foam layer reduced sensibility for two-point discrimination and pressure sensitivity at the fingertips, but Tegaderm did not. However, Tegaderm reduced static, but not dynamic, tactile discrimination. Adaptation of fingertip grip forces to surface friction measured by the rate of change of peak grip force, and grip force efficiency measured by the grip-load force ratio at lift, showed a proportional relationship with bare hands but were impaired with Tegaderm and foam. Activation of muscles engaged in precision grip also varied with the frictional surface with bare hands but not with Tegaderm and foam. The results suggest that sensitivity for static tactile discrimination is necessary for feedforward and feedback control of grip forces and for adaptive modulation of muscle activity during precision grasp.

  17. Effect of blocking tactile information from the fingertips on adaptation and execution of grip forces to friction at the grasping surface

    PubMed Central

    Bilaloglu, Seda; Lu, Ying; Geller, Daniel; Rizzo, John Ross; Aluru, Viswanath; Gardner, Esther P.

    2015-01-01

    Adaptation of fingertip forces to friction at the grasping surface is necessary to prevent use of inadequate or excessive grip forces. In the current study we investigated the effect of blocking tactile information from the fingertips noninvasively on the adaptation and efficiency of grip forces to surface friction during precision grasp. Ten neurologically intact subjects grasped and lifted an instrumented grip device with 18 different frictional surfaces under three conditions: with bare hands or with a thin layer of plastic (Tegaderm) or an additional layer of foam affixed to the fingertips. The coefficient of friction at the finger-object interface of each surface was obtained for each subject with bare hands and Tegaderm by measuring the slip ratio (grip force/load force) at the moment of slip. We found that the foam layer reduced sensibility for two-point discrimination and pressure sensitivity at the fingertips, but Tegaderm did not. However, Tegaderm reduced static, but not dynamic, tactile discrimination. Adaptation of fingertip grip forces to surface friction measured by the rate of change of peak grip force, and grip force efficiency measured by the grip-load force ratio at lift, showed a proportional relationship with bare hands but were impaired with Tegaderm and foam. Activation of muscles engaged in precision grip also varied with the frictional surface with bare hands but not with Tegaderm and foam. The results suggest that sensitivity for static tactile discrimination is necessary for feedforward and feedback control of grip forces and for adaptive modulation of muscle activity during precision grasp. PMID:26655820

  18. Observations of C-band Brightness Temperature from the Hurricane Imaging Radiometer (HIRAD) During GRIP

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Roberts, J. B.; Buckley, C. D.; Jones, W. L.; Biswas, S.; May, C.; Ruf, C. S.; Uhlhorn, E. W.; Atlas, R.; Albers, C.; Black, Peter G.

    2012-01-01

    HIRAD is a new technology developed by NASA/MSFC, in partnership with NOAA and the Universities of Central Florida, Michigan, and Alabama-Huntsville. HIRAD is designed to measure wind speed and rain rate over a wide swath in heavy-rain, strong-wind conditions. HIRAD is expected to eventually fly routinely on unmanned aerial vehicles (UAVs) such as Global Hawk over hurricanes threatening the U.S. coast and other Atlantic basin areas, and possibly in the Western Pacific as well. HIRAD first flew on GRIP in 2010 and is planned to fly 2012-14 on the NASA Hurricane and Severe Storm Sentinel (HS3) missions on the Global Hawk, a high-altitude UAV. HIRAD technology will eventually be used on a satellite platform to extend the dynamical range of Ocean Surface Wind (OSV) observations from space.

  19. Computer vision-based classification of hand grip variations in neurorehabilitation.

    PubMed

    Zariffa, José; Steeves, John D

    2011-01-01

    The complexity of hand function is such that most existing upper limb rehabilitation robotic devices use only simplified hand interfaces. This is in contrast to the importance of the hand in regaining function after neurological injury. Computer vision technology has been used to identify hand posture in the field of Human Computer Interaction, but this approach has not been translated to the rehabilitation context. We describe a computer vision-based classifier that can be used to discriminate rehabilitation-relevant hand postures, and could be integrated into a virtual reality-based upper limb rehabilitation system. The proposed system was tested on a set of video recordings from able-bodied individuals performing cylindrical grasps, lateral key grips, and tip-to-tip pinches. The overall classification success rate was 91.2%, and was above 98% for 6 out of the 10 subjects.

  20. Coordinated gripping of substrate by subunits of a AAA+ proteolytic machine

    PubMed Central

    Iosefson, Ohad; Nager, Andrew R.; Baker, Tania A.; Sauer, Robert T.

    2014-01-01

    Hexameric AAA+ unfoldases of ATP-dependent proteases and protein-remodeling machines use conserved loops that line the axial pore to apply force to substrates during the mechanical processes of protein unfolding and translocation. Whether loops from multiple subunits act independently or coordinately in these processes is a critical aspect of mechanism but is currently unknown for any AAA+ machine. By studying covalently linked hexamers of the E. coli ClpX unfoldase bearing different numbers and configurations of wild-type and mutant pore loops, we show that loops function synergistically, with the number of wild-type loops required for efficient degradation depending upon the stability of the protein substrate. Our results support a mechanism in which a power stroke initiated in one subunit of the ClpX hexamer results in the concurrent movement of all six pore loops, which coordinately grip and apply force to the substrate. PMID:25599533

  1. Hurricanes Karl and Tropical Storm Matthew Structure Observed by HIWRAP During GRIP

    NASA Astrophysics Data System (ADS)

    Heymsfield, G. M.; Guimond, S. R.; Tian, L.

    2012-12-01

    The dual-wavelength (Ku and Ka band) High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) flew for the first time on the Global Hawk during the 2010 Genesis and Rapid Intensification Processes (GRIP). HIWRAP is conical scanning and Doppler, and winds and reflectivity can be mapped within the swath below the Global Hawk. Two interesting cases from the HIWRAP flights were the rapid intensification of Hurricane Karl and the intensification of Tropical Storm Matthew. This presentation will highlight the precipitation and wind structure of these storms during their intensification as derived from the HIWRAP observations. If time permits and if available, highlights from HIWRAP observations from the Hurricane Severe Storm Sentinel (HS3) field campaign in September 2012 will be presented.

  2. Using the coefficient of variation to detect sincerity of effort of grip strength: a literature review.

    PubMed

    Shechtman, O

    2000-01-01

    Many clinicians use the coefficient of variation (CV) to assess sincerity of effort, without understanding the premise on which it is based or its physiological and mathematical bases. Clinicians who use computerized evaluation systems that calculate the CV may not even be aware of the formula used to derive it. The wide use of the CV in detecting sincerity of effort of grip strength is puzzling, since it lacks empirical support in the literature. This paper examines the physiological rationale for using measures of variability to detect sincerity of effort, the mathematical basis on which the CV is founded, and the reliability and validity of the CV. The conclusions based on this literature review are that the CV is not an appropriate method for determining whether an effort is sincere and that CV values may be inflated in injured patients with compromised hand strength.

  3. Coming to grips with breast cancer: the spouse's experience with his wife's first six months.

    PubMed

    Zahlis, Ellen H; Lewis, Frances M

    2010-01-01

    This study examines the experiences of 48 spouses of wives newly diagnosed with local or regional breast cancer. Their reported experiences were organized into the core construct of coming to grips reflected by four domains: (1) feeling nailed by the breast cancer, (2) changing us, (3) taking care of me, and (4) making things work. Prior studies have underestimated the extent to which the assumptive world and day-to-day lives of spouses are shattered by the diagnosis of breast cancer and the work they do to guess how to be supportive to their wives. Interventions are needed that directly assist spouses add to their ways of managing the intrusion of their wife's breast cancer in their lives.

  4. The Effect of Repetitive Rhythmic Precision Grip Task-Oriented Rehabilitation in Chronic Stroke Patients: A Pilot Study

    ERIC Educational Resources Information Center

    Dispa, Delphine; Lejeune, Thierry; Thonnard, Jean-Louis

    2013-01-01

    Most chronic stroke patients present with difficulty in the manipulation of objects. The aim of this study was to test whether an intensive program of precision grip training could improve hand functioning of patients at more than 6 months after a stroke. This was a cross-over study; hence, at inclusion, the patients were randomly divided into two…

  5. The role of GRIP1 and ephrin B3 in blood pressure control and vascular smooth muscle cell contractility

    PubMed Central

    Wang, Yujia; Wu, Zenghui; Luo, Hongyu; Peng, Junzheng; Raelson, John; Ehret, Georg B.; Munroe, Patricia B.; Stoyanova, Ekatherina; Qin, Zhao; Cloutier, Guy; Bradley, W. Edward; Wu, Tao; Shen, Jian-Zhong; Hu, Shenjiang; Wu, Jiangping

    2016-01-01

    Several erythropoietin-producing hepatocellular receptor B family (EPHB) and their ligands, ephrinBs (EFNBs), are involved in blood pressure regulation in animal models. We selected 528 single nucleotide polymorphisms (SNPs) within the genes of EPHB6, EFNB2, EFNB3 and GRIP1 in the EPH/EFN signalling system to query the International Blood Pressure Consortium dataset. A SNP within the glutamate receptor interacting protein 1 (GRIP1) gene presented a p-value of 0.000389, approaching the critical p-value of 0.000302, for association with diastolic blood pressure of 60,396 individuals. According to echocardiography, we found that Efnb3 gene knockout mice showed enhanced constriction in the carotid arteries. In vitro studies revealed that in mouse vascular smooth muscle cells, siRNA knockdown of GRIP1, which is in the EFNB3 reverse signalling pathway, resulted in increased contractility of these cells. These data suggest that molecules in the EPHB/EFNB signalling pathways, specifically EFNB3 and GRIP1, are involved blood pressure regulation. PMID:27941904

  6. GRIP1 interlinks N-cadherin and AMPA receptors at vesicles to promote combined cargo transport into dendrites

    PubMed Central

    Heisler, Frank F.; Lee, Han Kyu; Gromova, Kira V.; Pechmann, Yvonne; Schurek, Beate; Ruschkies, Laura; Schroeder, Markus; Schweizer, Michaela; Kneussel, Matthias

    2014-01-01

    The GluA2 subunit of AMPA-type glutamate receptors (AMPARs) regulates excitatory synaptic transmission in neurons. In addition, the transsynaptic cell adhesion molecule N-cadherin controls excitatory synapse function and stabilizes dendritic spine structures. At postsynaptic membranes, GluA2 physically binds N-cadherin, underlying spine growth and synaptic modulation. We report that N-cadherin binds to PSD-95/SAP90/DLG/ZO-1 (PDZ) domain 2 of the glutamate receptor interacting protein 1 (GRIP1) through its intracellular C terminus. N-cadherin and GluA2-containing AMPARs are presorted to identical transport vesicles for dendrite delivery, and live imaging reveals cotransport of both proteins. The kinesin KIF5 powers GluA2/N-cadherin codelivery by using GRIP1 as a multilink interface. Notably, GluA2 and N-cadherin use different PDZ domains on GRIP1 to simultaneously bind the transport complex, and interference with either binding motif impairs the turnover of both synaptic cargoes. Depolymerization of microtubules, deletion of the KIF5 motor domain, or specific blockade of AMPAR exocytosis affects delivery of GluA2/N-cadherin vesicles. At the functional level, interference with this cotransport reduces the number of spine protrusions and excitatory synapses. Our data suggest the concept that the multi-PDZ-domain adaptor protein GRIP1 can act as a scaffold at trafficking vesicles in the combined delivery of AMPARs and N-cadherin into dendrites. PMID:24639525

  7. Stretch calculated from grip distance accurately approximates mid-specimen stretch in large elastic arteries in uniaxial tensile tests

    PubMed Central

    Tian, Lian; Henningsen, Joseph; Salick, Max R.; Crone, Wendy C.; Gunderson, McLean; Dailey, Seth H.; Chesler, Naomi C.

    2015-01-01

    The mechanical properties of vascular tissues affect hemodynamics and can alter disease progression. The uniaxial tensile test is a simple and effective method for determining the stress-strain relationship in arterial tissue ex vivo. To enable calculation of strain, stretch can be measured directly with image tracking of markers on the tissue or indirectly from the distance between the grips used to hold the specimen. While the imaging technique is generally considered more accurate, it also requires more analysis, and the grip distance method is more widely used. The purpose of this study is to compare the stretch of the testing specimen calculated from the grip distance method to that obtained from the imaging method for canine descending aortas and large proximal pulmonary arteries. Our results showed a significant difference in stretch between the two methods; however, this difference was consistently less than 2%. Therefore, the grip distance method is an accurate approximation of the stretch in large elastic arteries in the uniaxial tensile test. PMID:25881308

  8. [Reliability and validity of the analysis of hand grip and pinch force in isometric and isokinetic conditions].

    PubMed

    Benaglia, P G; Franchignoni, F; Ferriero, G; Zebellin, G; Sartorio, F

    1999-01-01

    Strength measurement of the hand grip is at the core of most protocols of functional assessment of the upper limb and in rehabilitation plays a major role in the analysis of treatment efficacy and patients' occupational ability. The aims of this study were to: a) verify the repeatability of strength measurements made during performance of the hand grip and three types of pinch, carried out under isometric and isokinetic conditions; b) compare maximal isometric strength with the corresponding isokinetic value for each of the manoeuvres studied; c) investigate the correlations between the strength expressed in the different manoeuvres, under both isometric and isokinetic conditions. We studied 14 voluntary subjects over three sessions conducted at 48-hr intervals, employing a computerized isokinetic dynamometer Lido WorkSet equipped with device N(o) 21 for the study of pinch (lateral pinch, pulp pinch, chuck pinch) and device N(o) 52 for the grip study. Isometric contractions resulted stronger than isokinetic ones, and the hand grip was found to be the manoeuvre able to produce most strength. The repeatability of each strength measurement test over the three days was high (Intraclass Correlation Coefficients: 0.89-0.93). Correlations between the isometric and isokinetic performance for each of the manoeuvres examined were always high (Pearson's r coefficients: 0.89-0.95) as were those between the different manoeuvres, whether performed in isometric or isokinetic modality (r: 0.60-0.94).

  9. Role of the Visuomotor System in On-Line Attenuation of a Premovement Illusory Bias in Grip Aperture

    ERIC Educational Resources Information Center

    Heath, M.; Rival, C.

    2005-01-01

    In this investigation participants formulated a grip aperture (GA) consistent with the size of an object embedded within a Muller-Lyer (ML) figure prior to initiating visually guided grasping movements. The accuracy of the grasping response was emphasized to determine whether or not the visuomotor system might resolve the premovement bias in GA…

  10. Using goal- and grip-related information for understanding the correctness of other's actions: an ERP study.

    PubMed

    van Elk, Michiel; Bousardt, Roel; Bekkering, Harold; van Schie, Hein T

    2012-01-01

    Detecting errors in other's actions is of pivotal importance for joint action, competitive behavior and observational learning. Although many studies have focused on the neural mechanisms involved in detecting low-level errors, relatively little is known about error-detection in everyday situations. The present study aimed to identify the functional and neural mechanisms whereby we understand the correctness of other's actions involving well-known objects (e.g. pouring coffee in a cup). Participants observed action sequences in which the correctness of the object grasped and the grip applied to a pair of objects were independently manipulated. Observation of object violations (e.g. grasping the empty cup instead of the coffee pot) resulted in a stronger P3-effect than observation of grip errors (e.g. grasping the coffee pot at the upper part instead of the handle), likely reflecting a reorienting response, directing attention to the relevant location. Following the P3-effect, a parietal slow wave positivity was observed that persisted for grip-errors, likely reflecting the detection of an incorrect hand-object interaction. These findings provide new insight in the functional significance of the neurophysiological markers associated with the observation of incorrect actions and suggest that the P3-effect and the subsequent parietal slow wave positivity may reflect the detection of errors at different levels in the action hierarchy. Thereby this study elucidates the cognitive processes that support the detection of action violations in the selection of objects and grips.

  11. Predictive force programming in the grip-lift task: the role of memory links between arbitrary cues and object weight.

    PubMed

    Ameli, Mitra; Dafotakis, Manuel; Fink, Gereon R; Nowak, Dennis A

    2008-01-01

    We tested the ability of healthy participants to learn an association between arbitrary sensory cues and the weight of an object to be lifted using a precision grip between the index finger and thumb. Right-handed participants performed a series of grip-lift tasks with each hand. In a first experiment, participants lifted two objects of equal visual appearance which unexpectedly and randomly changed their weight. In two subsequent experiments, the change in object weight was indicated by cues, which were presented (i) visually or (ii) auditorily. When no cue about the weight of the object to be lifted was presented, participants programmed grip force according to the most recent lift, regardless of the hand used. In contrast, participants were able to rapidly establish an association between a particular sensory cue with a given weight and scaled grip force precisely to the actual weight thereafter, regardless of the hand used or the sensory modality of the cue. We discuss our data within the theoretical concept of internal models.

  12. Size-weight illusion and anticipatory grip force scaling following unilateral cortical brain lesion.

    PubMed

    Li, Yong; Randerath, Jennifer; Goldenberg, Georg; Hermsdörfer, Joachim

    2011-04-01

    The prediction of object weight from its size is an important prerequisite of skillful object manipulation. Grip and load forces anticipate object size during early phases of lifting an object. A mismatch between predicted and actual weight when two different sized objects have the same weight results in the size-weight illusion (SWI), the small object feeling heavier. This study explores whether lateralized brain lesions in patients with or without apraxia alter the size-weight illusion and impair anticipatory finger force scaling. Twenty patients with left brain damage (LBD, 10 with apraxia, 10 without apraxia), ten patients with right brain damage (RBD), and matched control subjects lifted two different-sized boxes in alternation. All subjects experienced a similar size-weight illusion. The anticipatory force scaling of all groups was in correspondence with the size cue: higher forces and force rates were applied to the big box and lower forces and force rates to the small box during the first lifts. Within few lifts, forces were scaled to actual object weight. Despite the lack of significant differences at group level, 5 out of 20 LBD patients showed abnormal predictive scaling of grip forces. They differed from the LBD patients with normal predictive scaling by a greater incidence of posterior occipito-parietal lesions but not by a greater incidence of apraxia. The findings do not support a more general role for the motor-dominant left hemisphere, or an influence of apraxia per se, in the scaling of finger force according to object properties. However, damage in the vicinity of the parietal-occipital junction may be critical for deriving predictions of weight from size.

  13. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2008-12-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2-cm thick tungsten grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150--650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  14. Grip force, EDL contractile properties, and voluntary wheel running after postdevelopmental myostatin depletion in mice.

    PubMed

    Personius, Kirkwood E; Jayaram, Aditi; Krull, David; Brown, Roger; Xu, Tianshun; Han, Bajin; Burgess, Kerri; Storey, Christopher; Shah, Bharati; Tawil, Rabi; Welle, Stephen

    2010-09-01

    There is no consensus about whether making muscles abnormally large by reducing myostatin activity affects force-generating capacity or the ability to perform activities requiring muscular endurance. We therefore examined grip force, contractile properties of extensor digitorum longus (EDL) muscles, and voluntary wheel running in mice in which myostatin was depleted after normal muscle development. Cre recombinase activity was induced to knock out exon 3 of the myostatin gene in 4-mo-old mice in which this exon was flanked by loxP sequences (Mstn[f/f]). Control mice with normal myostatin genes (Mstn[w/w]) received the same Cre-activating treatment. Myostatin depletion increased the mass of all muscles that were examined (gastrocnemius, quadriceps, tibialis anterior, EDL, soleus, triceps) by approximately 20-40%. Grip force, measured multiple times 2-22 wk after myostatin knockout, was not consistently greater in the myostatin-deficient mice. EDL contractile properties were determined 7-13 mo after myostatin knockout. Twitch force tended to be greater in myostatin-deficient muscles (+24%; P=0.09), whereas tetanic force was not consistently elevated (mean +11%; P=0.36), even though EDL mass was greater than normal in all myostatin-deficient mice (mean +36%; P<0.001). The force deficit induced by eccentric contractions was approximately twofold greater in myostatin-deficient than in normal EDL muscles (31% vs. 16% after five eccentric contractions; P=0.02). Myostatin-deficient mice ran 19% less distance (P<0.01) than control mice during the 12 wk following myostatin depletion, primarily because of fewer running bouts per night rather than diminished running speed or bout duration. Reduced specific tension (ratio of force to mass) and reduced running have been observed after muscle hypertrophy was induced by other means, suggesting that they are characteristics generally associated with abnormally large muscles rather than unique effects of myostatin deficiency.

  15. Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores

    NASA Astrophysics Data System (ADS)

    Montagnat, M.; Azuma, N.; Dahl-Jensen, D.; Eichler, J.; Fujita, S.; Gillet-Chaulet, F.; Kipfstuhl, S.; Samyn, D.; Svensson, A.; Weikusat, I.

    2014-07-01

    Fabric (distribution of crystallographic orientations) along the full NEEM ice core, Greenland was measured in the field by an automatic ice texture analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum at about 2300 m, which is typical of a deformation pattern mostly driven by uniaxial compression and simple shearing. A sharp increase in the fabric strengthening rate is observed at the Holocene to Wisconsin (HW) climatic transition. From a simple model we estimate that this depth is located at a transition from a state dominated by vertical compression to a state dominated by vertical shear. Comparisons are made to two others ice cores drilled along the same ridge; the GRIP ice core, drilled at the summit of the ice sheet, and the NGRIP ice core, drilled 325 km to the NNW of the summit along the ridge, and 365 km upstream from NEEM. This comparison tends to demonstrate that the ice viscosity change with the HW climatic transition must be associated with the shear-dominated state to induce the abrupt fabric strengthening observed at NEEM. This comparison therefore reflects the increasing role of shear deformation on the coring site when moving NW along the ridge from GRIP to NGRIP and NEEM. The difference in fabric profiles between NEEM and NGRIP also evidences a stronger lateral extension associated with a sharper ridge at NGRIP. Further along the core, centimeter scale abrupt texture (fabric and microstructure) variations are observed in the bottom part of the core. Their positions are in good agreement with the observed folding layers in Dahl-Jensen et al. (2013).

  16. Effects of local and core body temperature on grip force modulation during movement-induced load force fluctuations.

    PubMed

    Cheung, Stephen S; Reynolds, Luke F; Macdonald, Mark A B; Tweedie, Constance L; Urquhart, Robin L; Westwood, David A

    2008-05-01

    Impaired manual functioning often occurs when the hands are exposed to cold temperatures, but the underlying mechanism is not clearly understood. Tactile feedback is thought to provide important information during object manipulations in order to scale and regulate grip forces; however, topical anaesthetic-induced tactile sensation impairments may not realistically simulate the systemic neuromuscular impairment of the whole hand that could occur during cold temperature exposure. In two experiments, we studied the impact of (1) local hand cooling [thermoneutral finger skin temperature, cold (<8 degrees C)] and (2) core body temperature (thermoneutral core body temperature, pre-heated by 0.5 degrees C, pre-cooled by 0.5 degrees C) with cold hands on manual dexterity and the ability to control and co-ordinate grip forces during a cyclical load-lifting task. In Experiment 1 (n = 10), hand cooling significantly decreased Purdue Pegboard performance (P = 0.002), while increasing grip force by approximately 5 N during the cyclical load-lifting task compared to thermoneutral (P = 0.037). The temporal co-ordination of grip and load forces was unaffected by hand cooling. In Experiment 2 (n = 11), pegboard performance was impaired following hand cooling (P < 0.001), and to a greater extent when the body was pre-cooled (p < 0.001). However, neither grip force (P = 0.99) nor the temporal co-ordination of grasping and lifting forces (P = 0.85) were affected by core body temperature. These data support the existence of a robust centrally controlled feedforward system able to anticipate the dynamics of manual manipulations and accordingly regulate the temporal co-ordination of fingertip forces during object manipulation. This centrally controlled mechanism appears to differ from the mechanisms governing other aspects of manual dexterity.

  17. No strong correlations between serum cytokine levels, CMV serostatus and hand-grip strength in older subjects in the Berlin BASE-II cohort.

    PubMed

    Goldeck, David; Pawelec, Graham; Norman, Kristina; Steinhagen-Thiessen, Elisabeth; Oettinger, Lilly; Haehnel, Karin; Demuth, Ilja

    2016-02-01

    Hand-grip strength is strongly correlated with measures of muscle mass and can be taken to predict morbidity and mortality. The aim of this study was to investigate the relationship between hand-grip strength and other markers associated with immune ageing, such as Cytomegalovirus (CMV) infection, leukocyte telomere length and serum levels of inflammatory and anti-inflammatory markers in the elderly. We have assessed grip strength with the Smedley Dynamometer in younger (22-37 years) and older (60-85 years) men and women in a sample of people living in Berlin (the BASE-II study). Serum cytokine levels were determined by flow-cytometry, CMV serostatus via ELISA and leukocyte telomere length by quantitative PCR. IL-1β levels tended to be negatively associated with grip strength, but we did not find a significant association with IL-6 levels. CMV-seropositivity was not associated with higher levels of IL-1β, IL-6 or TNF, nor with weaker grip strength in men or women at any age. A putative general measure of organismal ageing, overall leukocyte telomere length, was also found not to be associated with lower grip strength in the elderly. Hand-grip strength remains an important biomarker independent of CMV infection or shorter telomere lengths, and poorly reflected in peripheral pro-inflammatory cytokine levels, all of which have been associated in some studies with frailty and mortality.

  18. Effects of changing gravity on anticipatory grip force control during point-to-point movements of a hand-held object.

    PubMed

    Nowak, D A; Hermsdörfer, J; Philipp, J; Marquardt, C; Glasauer, S; Mai, N

    2001-07-01

    We investigated the quality of predictive grip force control during gravity changes induced by parabolic flight maneuvers. During these maneuvers gravity varied: There were 2 periods of hypergravity, in which terrestrial gravity nearly doubled, and a 20-s period of microgravity, during which a manipulated object was virtually weightless. We determined grip and load forces during vertical point-to-point movements of an instrumented object. Point-to-point movements were a combination of static (stationary holding) and dynamic (continuous movements) task conditions, which were separately analyzed in our previous studies. Analysis of the produced grip forces revealed that grip adjustments were closely linked to load force fluctuations under each gravity condition. In particular, grip force maxima coincided closely in time with load force peaks, although these occurred at different phases of the movement depending on the gravity level. However, quantitative analysis of the ratio of maximum grip force to the corresponding load force peak revealed an increased force ratio during microgravity when compared to that during normal and hypergravity. We hypothesize that the impaired precision of force coupling with respect to force magnitude during microgravity results from reduced feedback information about the object's mass during the stationary holding of the object in between each movement. The results indicate that the temporal grip force regulation is highly automatized and stable, whereas economical planning of force magnitude is more flexible and might reflect changes of the external loading condition.

  19. SAO and Kelvin Waves in the EuroGRIPS GCMS and the UK Meteorological Offices Analyses

    NASA Technical Reports Server (NTRS)

    Amodei, M.; Pawson, S.; Scaife, A. A.; Lahoz, W.; Langematz, U.; Li, Ding Min; Simon, P.

    2000-01-01

    This work is an intercomparison of four tropospheric-stratospheric climate models, the Unified Model (UM) of the U.K. Meteorological Office (UKMO), the model of the Free University in Berlin (FUB). the ARPEGE-climat model of the National Center for Meteorological Research (CNRM), and the Extended UGAMP GCM (EUGCM) of the Center for Global Atmospheric Modelling (CGAM), against the UKMO analyses. This comparison has been made in the framework of the "GSM-Reality Intercomparison Project for SPARC" (GRIPS). SPARC (Stratospheric Processes and their Role in Climate) aims are to investigate the effects of the middle atmosphere on climate and the GRIPS purpose is to organized a comprehensive assessment of current Middle Atmosphere-Climate Models (MACMs). The models integrations were made without identical contraints e.g. boundary conditions, incoming solar radiation). All models are able to represent the dominant features of the extratropical circulation. In this paper, the structure of the tropical winds and the strengths of the Kelvin waves are examined. Explanations for the differences exhibited. between the models. as well as between models and analyses, are also proposed. In the analyses a rich spectrum of waves (eastward and westward) is present and contributes to drive the SAO (SemiAnnual Oscillation) and the QBO (Quasi-Biennal Oscillation). The amplitude of the Kelvin waves is close to the one observed in UARS (Upper Atmosphere Research Satellite) data. In agreement with observations, the Kelvin waves generated in the models propagate into the middle atmosphere as wave packets which underlines convective forcing origin. In most models, slow Kelvin waves propagate too high and are hence overestimated in the upper stratosphere and in the mesosphere, except for the UM which is more diffusive. These waves are not sufficient to force realistic westerlies of the QBO or SAO westerly phases. If the SAO is represented by all models only two of them are able to generate

  20. Effort, performance, and motivation: insights from robot-assisted training of human golf putting and rat grip strength.

    PubMed

    Duarte, Jaime E; Gebrekristos, Berkenesh; Perez, Sergi; Rowe, Justin B; Sharp, Kelli; Reinkensmeyer, David J

    2013-06-01

    Robotic devices can modulate success rates and required effort levels during motor training, but it is unclear how this affects performance gains and motivation. Here we present results from training unimpaired humans in a virtual golf-putting task, and training spinal cord injured (SCI) rats in a grip strength task using robotically modulated success rates and effort levels. Robotic assistance in golf practice increased trainees feelings of competence, and, paradoxically, increased their sense effort, even though it had mixed effects on learning. Reducing effort during a grip strength training task led rats with SCI to practice the task more frequently. However, the more frequent practice of these rats did not cause them to exceed the strength gains achieved by rats that exercised less often at higher required effort levels. These results show that increasing success and decreasing effort with robots increases motivation, but has mixed effects on performance gains.

  1. Object orientation in two dimensional grasp with friction towards minimization of gripping power.

    PubMed

    Ito, Satoshi; Takeuchi, Shouta; Sasaki, Minoru

    2009-09-01

    This article reports an analysis of two dimensional grasp where a convex rigid object is grasped by two contact points with friction. The purpose is to find the object orientation that minimizes the norm of the contact force vector, each element of which is composed from the normal force and friction force at each contact point. The formulation of this problem requires some equality or inequality conditions. In the analysis, the solution of the equality conditions is parameterized at first. Based on the fact that the norm of the contact force vector becomes monotonic increasing function of this parameter, the minimal parameter values are calculated by means of the piecewise analysis. Using the relation between the friction coefficient and the apex angle of the friction cone effectively, the following result is obtained: the norm of the contact force, i.e, gripping power becomes locally minimal at the object orientation where the intersection point of the upper sides of two friction cones is located in opposite direction of the gravity from the center of mass of the grasped object.

  2. Simple and Reliable Method to Estimate the Fingertip Static Coefficient of Friction in Precision Grip.

    PubMed

    Barrea, Allan; Bulens, David Cordova; Lefevre, Philippe; Thonnard, Jean-Louis

    2016-01-01

    The static coefficient of friction (µstatic) plays an important role in dexterous object manipulation. Minimal normal force (i.e., grip force) needed to avoid dropping an object is determined by the tangential force at the fingertip-object contact and the frictional properties of the skin-object contact. Although frequently assumed to be constant for all levels of normal force (NF, the force normal to the contact), µ static actually varies nonlinearly with NF and increases at low NF levels. No method is currently available to measure the relationship between µstatic and NF easily. Therefore, we propose a new method allowing the simple and reliable measurement of the fingertip µstatic at different NF levels, as well as an algorithm for determining µstatic from measured forces and torques. Our method is based on active, back-and-forth movements of a subject's finger on the surface of a fixed six-axis force and torque sensor. µstatic is computed as the ratio of the tangential to the normal force at slip onset. A negative power law captures the relationship between µstatic and NF. Our method allows the continuous estimation of µstatic as a function of NF during dexterous manipulation, based on the relationship between µstatic and NF measured before manipulation.

  3. Reconstructed animation from four-phase grip MRI of the wrist with ulnar-sided pain.

    PubMed

    Oda, T; Wada, T; Iba, K; Aoki, M; Tamakawa, M; Yamashita, T

    2013-09-01

    In order to visualize dynamic variations related to ulnar-sided wrist pain, animation was reconstructed from T2* coronal-sectioned magnetic resonance imaging in each of the four phases of grip motion for nine wrists in patients with ulnar pain. Eight of the nine wrists showed a positive ulnar variance of less than 2 mm. Ulnocarpal impaction and triangular fibrocartilage complex injury were assessed on the basis of animation and arthroscopy, respectively. Animation revealed ulnocarpal impaction in four wrists. In one of the four wrists, the torn portion of the articular disc was impinged between the ulnar head and ulnar proximal side of the lunate. In another wrist, the ulnar head impacted the lunate directly through the defect in the articular disc that had previously been excised. An ulnar shortening osteotomy successfully relieved ulnar wrist pain in all four cases with both ulnocarpal impaction and Palmer's Class II triangular fibrocartilage complex tears. This method demonstrated impairment of the articular disc and longitudinal instability of the distal radioulnar joint simultaneously and should be of value in investigating dynamic pathophysiology causing ulnar wrist pain.

  4. Optimal combination of auxiliary device size and its location on chopsticks for food-gripping performances.

    PubMed

    Lee, Yu-Chi; Chen, Yi-Lang

    2012-08-01

    Chopsticks are the main utensils for daily dining in Asia. Lee and Chen (2008) designed a novel auxiliary device for chopsticks that successfully converts people experienced in scissor-pinching to the correct method: pincer-pinching. This study attempts to assess the optimal combination of auxiliary size and location on chopstick stems for food-gripping performance. Twenty-four male participants experienced in scissor-pinching were recruited for the experiment. They were requested to perform 3 simulated tasks (force, precision, and stability) using 6 auxiliary combinations of 3 sizes (15, 25, and 35 mm) of chopsticks and 2 locations (on top of the stems and 1/3 stem-length from the top). Results indicate that auxiliary device size influenced simulated task performance and the user's subjective rating of chopsticks use. The auxiliary device measuring 15 mm wide showed the best performance in pinching force, precision, stability, and subjective rating. The location of the auxiliary device only affected the pinching force. The auxiliary device produced greater force when located at the top of the stems. This finding improves the application of auxiliary devices to chopstick operation.

  5. Effects of material properties and object orientation on precision grip kinematics.

    PubMed

    Paulun, Vivian C; Gegenfurtner, Karl R; Goodale, Melvyn A; Fleming, Roland W

    2016-08-01

    Successfully picking up and handling objects requires taking into account their physical properties (e.g., material) and position relative to the body. Such features are often inferred by sight, but it remains unclear to what extent observers vary their actions depending on the perceived properties. To investigate this, we asked participants to grasp, lift and carry cylinders to a goal location with a precision grip. The cylinders were made of four different materials (Styrofoam, wood, brass and an additional brass cylinder covered with Vaseline) and were presented at six different orientations with respect to the participant (0°, 30°, 60°, 90°, 120°, 150°). Analysis of their grasping kinematics revealed differences in timing and spatial modulation at all stages of the movement that depended on both material and orientation. Object orientation affected the spatial configuration of index finger and thumb during the grasp, but also the timing of handling and transport duration. Material affected the choice of local grasp points and the duration of the movement from the first visual input until release of the object. We find that conditions that make grasping more difficult (orientation with the base pointing toward the participant, high weight and low surface friction) lead to longer durations of individual movement segments and a more careful placement of the fingers on the object.

  6. A method to study precision grip control in viscoelastic force fields using a robotic gripper.

    PubMed

    Lambercy, Olivier; Metzger, Jean-Claude; Santello, Marco; Gassert, Roger

    2015-01-01

    Instrumented objects and multipurpose haptic displays have commonly been used to investigate sensorimotor control of grasping and manipulation. A major limitation of these devices, however, is the extent to which the experimenter can vary the interaction dynamics to fully probe sensorimotor control mechanisms. We propose a novel method to study precision grip control using a grounded robotic gripper with two moving, mechanically coupled finger pads instrumented with force sensors. The device is capable of stably rendering virtual mechanical properties with a wide dynamic range of achievable impedances. Eight viscoelastic force fields with different combinations of stiffness and damping parameters were implemented, and tested on eight healthy subjects performing 30 consecutive repetitions of a grasp, hold, and release task with time and position constraints. Rates of thumb and finger force were found to be highly correlated (r>0.9) during grasping, revealing that, despite the mechanical coupling of the two finger pads, subjects performed grasping movements in a physiological fashion. Subjects quickly adapted to the virtual dynamics (within seven trials), but, depending on the presented force field condition, used different control strategies to correctly perform the task. The proof of principle presented in this paper underscores the potential of such a one-degree-of-freedom robotic gripper to study neural control of grasping, and to provide novel insights on sensorimotor control mechanisms.

  7. The effectiveness of combined gripping method in tensile testing of UHMWPE single yarn

    NASA Astrophysics Data System (ADS)

    Wang, H. X.; Hazell, P. J.; Shankar, K.; Morozov, E. V.; Escobedo, J. P.

    2015-07-01

    This paper presents the experimental study on the effectiveness of combined gripping method employed in the tensile testing of UHMWPE (Dyneema® SK75) single yarn. Seven different solutions including epoxy, acrylic, and ethyl cyanoacrylate adhesives were tested under quasi-static loadings in order to determine the most effective adhesive for bonding UHMWPE single yarn to aluminium sheets. The ethyl cyanoacrylate adhesive combined with polyolefin surface primer was found to be the best choice which could prevent yarn slippage and ensure the failure of yarn occurs in the gauge section. The single yarns were then tested at three strain rates of 3.3×10-5, 3.3×10-3, and 0.33 s-1. The tensile strength, maximum strain, and Young's modulus were determined from the measured stress-strain curves and compared with the values from literature; the results showed these tensile properties of single yarn depend on strain rate over the range tested.

  8. DAWN Coherent Wind Profiling Lidar Flights on NASA's DC-8 During GRIP

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.; Beyon, Jeffrey Y.; Creary, Garfield A.; Koch, Grady J.; Petros, Mulugeta; Petzar, Paul J.; Singh, Upendra N.; Trieu, Bo C.; Yu, Jirong

    2011-01-01

    Almost from their invention, lasers have been used to measure the velocity of wind and objects; over distances of cm to 10s of km. Long distance (remote) sensing of wind has been accomplished with continuous-wave (CW), focused pulsed, and collimated pulsed lasers; with direct and coherent (heterodyne) optical detection; and with a multitude of laser wavelengths. Airborne measurement of wind with pulsed, coherent-detection lidar was first performed in 1971 with a CW CO2 laser1, in 1972 with a pulsed CO2 laser2, in 1993 with a pulsed 2-micron laser3, and in 1999 with a pulsed CO2 laser and nadir-centered conical scanning4. Of course there were many other firsts and many other groups doing lidar wind remote sensing with coherent and direct detection. A very large FOM coherent wind lidar has been built by LaRC and flown on a DC-8. However a burn on the telescope secondary mirror prevented the full demonstration of high FOM. Both the GRIP science product and the technology and technique demonstration from aircraft are important to NASA. The technology and technique demonstrations contribute to our readiness for the 3D Winds space mission. The data analysis is beginning and we hope to present results at the conference.

  9. The use of the rapid exchange grip test in detecting sincerity of effort, Part II: validity of the test.

    PubMed

    Shechtman, O; Taylor, C

    2000-01-01

    The rapid exchange grip (REG) test was developed to identify patients exerting insincere effort. The premise of the REG test is that a maximal, sincere effort yields a "negative REG," in which peak static grip (SG) scores are greater than peak REG scores, and that a submaximal, insincere effort yields a "positive REG," in which REG scores are greater than SG scores. There is disagreement in the literature concerning what constitutes a positive REG test, suggesting that the REG may not be a valid measure of sincerity of effort. The purpose of the present study was to investigate the validity of the REG test by examining its premise as well as its sensitivity and specificity values. The 146 uninjured subjects performed a series of randomized grip strength tests, exerting both maximal and submaximal efforts. The tests included the REG at hand switch rates of 45 rpm (REG-45) and 60 rpm (REG-60), the maximal static grip test (MSGT), and the five-rung test (5R). Our findings supported the concept of a "negative REG" for both REG maneuvers and both comparative SG tests. The concept of a "positive REG," however, was supported only when peak REG scores were compared with peak 5R scores. The authors found relatively low sensitivity and specificity values, suggesting that the REG test may not be sensitive or specific enough to effectively detect sincerity of effort. The authors discuss the likelihood that mistakes will be made when the REG test is used to diagnose sincerity of effort and the possible consequences of making such mistakes.

  10. Using Goal- and Grip-Related Information for Understanding the Correctness of Other’s Actions: An ERP Study

    PubMed Central

    van Elk, Michiel; Bousardt, Roel; Bekkering, Harold; van Schie, Hein T.

    2012-01-01

    Detecting errors in other’s actions is of pivotal importance for joint action, competitive behavior and observational learning. Although many studies have focused on the neural mechanisms involved in detecting low-level errors, relatively little is known about error-detection in everyday situations. The present study aimed to identify the functional and neural mechanisms whereby we understand the correctness of other’s actions involving well-known objects (e.g. pouring coffee in a cup). Participants observed action sequences in which the correctness of the object grasped and the grip applied to a pair of objects were independently manipulated. Observation of object violations (e.g. grasping the empty cup instead of the coffee pot) resulted in a stronger P3-effect than observation of grip errors (e.g. grasping the coffee pot at the upper part instead of the handle), likely reflecting a reorienting response, directing attention to the relevant location. Following the P3-effect, a parietal slow wave positivity was observed that persisted for grip-errors, likely reflecting the detection of an incorrect hand-object interaction. These findings provide new insight in the functional significance of the neurophysiological markers associated with the observation of incorrect actions and suggest that the P3-effect and the subsequent parietal slow wave positivity may reflect the detection of errors at different levels in the action hierarchy. Thereby this study elucidates the cognitive processes that support the detection of action violations in the selection of objects and grips. PMID:22606261

  11. Hand grips strength effect on motor function in human brain using fMRI: a pilot study

    NASA Astrophysics Data System (ADS)

    Ismail, S. S.; Mohamad, M.; Syazarina, S. O.; Nafisah, W. Y.

    2014-11-01

    Several methods of motor tasks for fMRI scanning have been evolving from simple to more complex tasks. Motor tasks on upper extremity were applied in order to excite the increscent of motor activation on contralesional and ipsilateral hemispheres in brain. The main objective of this study is to study the different conditions for motor tasks on upper extremity that affected the brain activation. Ten healthy right handed with normal vision (3 male and 7 female, age range=20-30 years, mean=24.6 years, SD=2.21) participated in this study. Prior to the scanning, participants were trained on hand grip tasks using rubber ball and pressure gauge tool outside the scanner. During fMRI session, a block design with 30-s task blocks and alternating 30-s rest periods was employed while participants viewed a computer screen via a back projection-mirror system and instructed to follow the instruction by gripping their hand with normal and strong grips using a rubber ball. Statistical Parametric mapping (SPM8) software was used to determine the brain activation. Both tasks activated the primary motor (M1), supplementary motor area (SMA), dorsal and ventral of premotor cortex area (PMA) in left hemisphere while in right hemisphere the area of primary motor (M1) somatosensory was activated. However, the comparison between both tasks revealed that the strong hand grip showed the higher activation at M1, PMA and SMA on left hemisphere and also the area of SMA on right hemisphere. Both conditions of motor tasks could provide insights the functional organization on human brain.

  12. Lipodystrophy and Inflammation Predict Later Grip Strength in HIV-Infected Men: The MACS Body Composition Substudy

    PubMed Central

    Crawford, Keith W.; Li, Xiuhong; Xu, Xiaoqiang; Abraham, Alison G.; Dobs, Adrian S.; Margolick, Joseph B.; Palella, Frank J.; Kingsley, Lawrence A.; Witt, Mallory D.

    2013-01-01

    Abstract Body fat changes in HIV-infected persons are associated with increased systemic inflammation and increased mortality. It is unknown whether lipodystrophy is also associated with declines in physical function. Between 2001 and 2003, 33 HIV-infected men with evidence of lipodystrophy (LIPO+), 23 HIV-infected men without lipodystrophy (LIPO−), and 33 seronegative men were recruited from the Multicenter AIDS Cohort Study (MACS) for the Body Composition substudy. Visceral adipose tissue (VAT) was assessed by quantitative computed tomography. Lean body mass (LBM) and extremity fat were measured by dual-energy x-ray absorptiometry. Insulin resistance was estimated by Homeostatic Model Assessment (HOMA). Serum interleukin (IL)-6, soluble tumor necrosis factor (TNF)-α receptors I and II (sTNFRI and sTNFRII), and highly sensitive C-reactive protein (hs-CRP) concentrations were quantified from archived serum samples. These measurements were correlated with grip strength measured in 2007 using linear regression. At the substudy visit, the LIPO+ group had higher HOMA, sTNFRI, sTNFRII, and IL-6 levels than the LIPO− group. In 2007, the LIPO+ group had lower median grip strength than the LIPO− group (34.4 vs. 42.7 kg, p=0.002). Multivariable analysis of HIV+ men showed older age, lower LBM, higher sTNFRII concentrations, and LIPO+ status [adjusted mean difference −4.9 kg (p=0.045)] at the substudy visit were independently associated with lower subsequent grip strength. Inflammation, lower LBM, and lipodystrophy in HIV-infected men were associated with lower subsequent grip strength. These findings suggest that inflammation may contribute to declines in functional performance, independent of age. PMID:23550976

  13. Self-gripping mesh versus fibrin glue fixation in laparoscopic inguinal hernia repair: a randomized prospective clinical trial in young and elderly patients

    PubMed Central

    Bindi, Marco; Rivelli, Matteo; Solej, Mario; Enrico, Stefano; Martino, Valter

    2016-01-01

    Abstract Laparoscopic transabdominal preperitoneal inguinal hernia repair is a safe and effective technique. In this study we tested the hypothesis that self-gripping mesh used with the laparoscopic approach is comparable to polypropylene mesh in terms of perioperative complications, against a lower overall cost of the procedure. We carried out a prospective randomized trial comparing a group of 30 patients who underwent laparoscopic inguinal hernia repair with self-gripping mesh versus a group of 30 patients who received polypropylene mesh with fibrin glue fixation. There were no statistically significant differences between the two groups with regard to intraoperative variables, early or late intraoperative complications, chronic pain or recurrence. Self-gripping mesh in transabdominal hernia repair was found to be a valid alternative to polypropylene mesh in terms of complications, recurrence and postoperative pain. The cost analysis and comparability of outcomes support the preferential use of self-gripping mesh. PMID:28352842

  14. The effect of the “rod-and-frame” illusion on grip planning in a sequential object manipulation task

    PubMed Central

    van der Kamp, John; Steenbergen, Bert

    2007-01-01

    We investigated the effect of visual context (i.e., a visual illusion) on the planning of a sequential object manipulation task. Participants (n = 13) had to grasp a rod embedded in a “rod-and-frame” illusion and insert the rod-end into a tight hole in a pre-defined way. The grip type (defined by start posture, either pronated or supinated; and end posture, either comfortable or uncomfortable) used to grasp the rod was registered as a macroscopic variable of motor planning. Different rod orientations forced the participants to switch between grip types. As expected, most participants switched between pronated and supinated start postures, such that they ended the movement with a comfortable end posture. As it has been argued that planning is dependent on visual context information, we hypothesized that the visual illusion would affect the specific rod orientation at which participants would switch into a different grip type. This hypothesis was confirmed. More specifically, the illusion affected the critical spatial information that is used for action planning. Collectively, these findings are the first to show an effect of an illusion on motor planning in a sequential object manipulation task. PMID:17909769

  15. Rapamycin increases grip strength and attenuates age-related decline in maximal running distance in old low capacity runner rats.

    PubMed

    Xue, Qian-Li; Yang, Huanle; Li, Hui-Fen; Abadir, Peter M; Burks, Tyesha N; Koch, Lauren G; Britton, Steven L; Carlson, Joshua; Chen, Laura; Walston, Jeremy D; Leng, Sean X

    2016-04-01

    Rapamycin is known to extend lifespan. We conducted a randomized placebo-controlled study of enteric rapamycin-treatment to evaluate its effect on physical function in old low capacity runner (LCR) rats, a rat model selected from diverse genetic background for low intrinsic aerobic exercise capacity without genomic manipulation and characterized by increased complex disease risks and aging phenotypes. The study was performed in 12 male and 16 female LCR rats aged 16-22 months at baseline. The treatment group was fed with rapamycin-containing diet pellets at approximately 2.24mg/kg body weight per day and the placebo group with the same diet without rapamycin for six months. Observation was extended for additional 2 months. Physical function measurements include grip strength measured as maximum tensile force using a rat grip strength meter and maximum running distance (MRD) using rat physical treadmill test. The results showed that rapamycin improved grip strength by 13% (p=.036) and 60% (p=.001) from its baseline in female and male rats, respectively. Rapamycin attenuated MRD decline by 66% (p=.001) and 46% (p=.319) in females and males, respectively. These findings provide initial evidence for beneficial effect of rapamycin on physical functioning in an aging rat model of high disease risks with significant implication in humans.

  16. Observations During GRIP from HIRAD: Images of C-Band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Jones, W. L.; Ruf, C. S.; Uhlhorn, E. W.; Biswas, S.; May, C.; Shah, G.; Black, P.; Buckley, C. D.

    2012-01-01

    HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be inferred. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. To the extent possible, comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eyewall, location of vortex wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

  17. GRiP - A flexible approach for calculating risk as a function of consequence, vulnerability, and threat.

    SciTech Connect

    Whitfield, R. G.; Buehring, W. A.; Bassett, G. W.

    2011-04-08

    Get a GRiP (Gravitational Risk Procedure) on risk by using an approach inspired by the physics of gravitational forces between body masses! In April 2010, U.S. Department of Homeland Security Special Events staff (Protective Security Advisors [PSAs]) expressed concern about how to calculate risk given measures of consequence, vulnerability, and threat. The PSAs believed that it is not 'right' to assign zero risk, as a multiplicative formula would imply, to cases in which the threat is reported to be extremely small, and perhaps could even be assigned a value of zero, but for which consequences and vulnerability are potentially high. They needed a different way to aggregate the components into an overall measure of risk. To address these concerns, GRiP was proposed and developed. The inspiration for GRiP is Sir Isaac Newton's Universal Law of Gravitation: the attractive force between two bodies is directly proportional to the product of their masses and inversely proportional to the squares of the distance between them. The total force on one body is the sum of the forces from 'other bodies' that influence that body. In the case of risk, the 'other bodies' are the components of risk (R): consequence, vulnerability, and threat (which we denote as C, V, and T, respectively). GRiP treats risk as if it were a body within a cube. Each vertex (corner) of the cube represents one of the eight combinations of minimum and maximum 'values' for consequence, vulnerability, and threat. The risk at each of the vertices is a variable that can be set. Naturally, maximum risk occurs when consequence, vulnerability, and threat are at their maximum values; minimum risk occurs when they are at their minimum values. Analogous to gravitational forces among body masses, the GRiP formula for risk states that the risk at any interior point of the box depends on the squares of the distances from that point to each of the eight vertices. The risk value at an interior (movable) point will be

  18. Tyre-road grip coefficient assessment - Part II: online estimation using instrumented vehicle, extended Kalman filter, and neural network

    NASA Astrophysics Data System (ADS)

    Luque, Pablo; Mántaras, Daniel A.; Fidalgo, Eloy; Álvarez, Javier; Riva, Paolo; Girón, Pablo; Compadre, Diego; Ferran, Jordi

    2013-12-01

    The main objective of this work is to determine the limit of safe driving conditions by identifying the maximal friction coefficient in a real vehicle. The study will focus on finding a method to determine this limit before reaching the skid, which is valuable information in the context of traffic safety. Since it is not possible to measure the friction coefficient directly, it will be estimated using the appropriate tools in order to get the most accurate information. A real vehicle is instrumented to collect information of general kinematics and steering tie-rod forces. A real-time algorithm is developed to estimate forces and aligning torque in the tyres using an extended Kalman filter and neural networks techniques. The methodology is based on determining the aligning torque; this variable allows evaluation of the behaviour of the tyre. It transmits interesting information from the tyre-road contact and can be used to predict the maximal tyre grip and safety margin. The maximal grip coefficient is estimated according to a knowledge base, extracted from computer simulation of a high detailed three-dimensional model, using Adams® software. The proposed methodology is validated and applied to real driving conditions, in which maximal grip and safety margin are properly estimated.

  19. Modified forelimb grip strength test detects aging-associated physiological decline in skeletal muscle function in male mice

    PubMed Central

    Takeshita, Hikari; Yamamoto, Koichi; Nozato, Satoko; Inagaki, Tadakatsu; Tsuchimochi, Hirotsugu; Shirai, Mikiyasu; Yamamoto, Ryohei; Imaizumi, Yuki; Hongyo, Kazuhiro; Yokoyama, Serina; Takeda, Masao; Oguro, Ryosuke; Takami, Yoichi; Itoh, Norihisa; Takeya, Yasushi; Sugimoto, Ken; Fukada, So-ichiro; Rakugi, Hiromi

    2017-01-01

    The conventional forelimb grip strength test is a widely used method to assess skeletal muscle function in rodents; in this study, we modified this method to improve its variability and consistency. The modified test had lower variability among trials and days than the conventional test in young C57BL6 mice, especially by improving the variabilities in male. The modified test was more sensitive than the conventional test to detect a difference in motor function between female and male mice, or between young and old male mice. When the modified test was performed on male mice during the aging process, reduction of grip strength manifested between 18 and 24 months of age at the group level and at the individual level. The modified test was similar to the conventional test in detecting skeletal muscle dysfunction in young male dystrophic mice. Thus, the modified forelimb grip strength test, with its improved validity and reliability may be an ideal substitute for the conventional method. PMID:28176863

  20. Association of the AMPA receptor-related postsynaptic density proteins GRIP and ABP with subsets of glutamate-sensitive neurons in the rat retina.

    PubMed

    Gábriel, Robert; de Souza, Sunita; Ziff, Edward B; Witkovsky, Paul

    2002-07-22

    We used specific antibodies against two postsynaptic density proteins, GRIP (glutamate receptor interacting protein) and ABP (AMPA receptor-binding protein), to study their distribution in the rat retina. In the central nervous system, it has been shown that both proteins bind strongly to the AMPA glutamate receptor (GluR) 2/3 subunits, but not other GluRs, through a set of three PDZ domains. Western blots detected a single GRIP protein that was virtually identical in retina and brain, whereas retinal ABP corresponded to only one of three ABP peptides found in brain. The retinal distributions of GluR2/3, GRIP, and ABP immunoreactivity (IR) were similar but not identical. GluR2/3 immunoreactivity (IR) was abundant in both plexiform layers and in large perikarya. ABP IR was concentrated in large perikarya but was sparse in the plexiform layers, whereas GRIP IR was relatively more abundant in the plexiform layers than in perikarya. Immunolabel for these three antibodies consisted of puncta < or = 0.2 microm in diameter. The cellular localization of GRIP and ABP IR was examined by double labeling subclasses of retinal neuron with characteristic marker proteins, e.g., calbindin. GRIP, ABP, and GluR2/3 IR were detected in horizontal cells, dopaminergic and glycinergic AII amacrine cells and large ganglion cells. Immunolabel was absent in rod bipolar and weak or absent in cholinergic amacrine cells. By using the tyramide method of signal amplification, a colocalization of GluR2/3 was found with either GRIP or ABP in horizontal cell terminals, and perikarya of amacrine and ganglion cells. Our results show that ABP and GRIP colocalize with GluR2/3 in particular subsets of retinal neuron, as was previously established for certain neurons in the brain.

  1. Perturbing the action observation network during perception and categorization of actions' goals and grips: state-dependency and virtual lesion TMS effects.

    PubMed

    Jacquet, Pierre O; Avenanti, Alessio

    2015-03-01

    Watching others grasping and using objects activates an action observation network (AON), including inferior frontal (IFC), anterior intraparietal (AIP), and somatosensory cortices (S1). Yet, causal evidence of the differential involvement of such AON sensorimotor nodes in representing high- and low-level action components (i.e., end-goals and grip type) is meager. To address this issue, we used transcranial magnetic stimulation-adaptation (TMS-A) during 2 novel action perception tasks. Participants were shown adapting movies displaying a demonstrator performing goal-directed actions with a tool, using either power or precision grips. They were then asked to match the end-goal (Goal-recognition task) or the grip (Grip-recognition task) of actions shown in test pictures to the adapting movies. TMS was administered over IFC, AIP, or S1 during presentation of test pictures. Virtual lesion-like effects were found in the Grip-recognition task where IFC stimulation induced a general performance decrease, suggesting a critical role of IFC in perceiving grips. In the Goal-recognition task, IFC and S1 stimulation differently affected the processing of "adapted" and "nonadapted" goals. These "state-dependent" effects suggest that the overall goal of seen actions is encoded into functionally distinct and spatially overlapping neural populations in IFC-S1 and such encoding is critical for recognizing and understanding end-goals.

  2. Self-organization, free energy minimization, and optimal grip on a field of affordances.

    PubMed

    Bruineberg, Jelle; Rietveld, Erik

    2014-01-01

    In this paper, we set out to develop a theoretical and conceptual framework for the new field of Radical Embodied Cognitive Neuroscience. This framework should be able to integrate insights from several relevant disciplines: theory on embodied cognition, ecological psychology, phenomenology, dynamical systems theory, and neurodynamics. We suggest that the main task of Radical Embodied Cognitive Neuroscience is to investigate the phenomenon of skilled intentionality from the perspective of the self-organization of the brain-body-environment system, while doing justice to the phenomenology of skilled action. In previous work, we have characterized skilled intentionality as the organism's tendency toward an optimal grip on multiple relevant affordances simultaneously. Affordances are possibilities for action provided by the environment. In the first part of this paper, we introduce the notion of skilled intentionality and the phenomenon of responsiveness to a field of relevant affordances. Second, we use Friston's work on neurodynamics, but embed a very minimal version of his Free Energy Principle in the ecological niche of the animal. Thus amended, this principle is helpful for understanding the embeddedness of neurodynamics within the dynamics of the system "brain-body-landscape of affordances." Next, we show how we can use this adjusted principle to understand the neurodynamics of selective openness to the environment: interacting action-readiness patterns at multiple timescales contribute to the organism's selective openness to relevant affordances. In the final part of the paper, we emphasize the important role of metastable dynamics in both the brain and the brain-body-environment system for adequate affordance-responsiveness. We exemplify our integrative approach by presenting research on the impact of Deep Brain Stimulation on affordance responsiveness of OCD patients.

  3. Self-organization, free energy minimization, and optimal grip on a field of affordances

    PubMed Central

    Bruineberg, Jelle; Rietveld, Erik

    2014-01-01

    In this paper, we set out to develop a theoretical and conceptual framework for the new field of Radical Embodied Cognitive Neuroscience. This framework should be able to integrate insights from several relevant disciplines: theory on embodied cognition, ecological psychology, phenomenology, dynamical systems theory, and neurodynamics. We suggest that the main task of Radical Embodied Cognitive Neuroscience is to investigate the phenomenon of skilled intentionality from the perspective of the self-organization of the brain-body-environment system, while doing justice to the phenomenology of skilled action. In previous work, we have characterized skilled intentionality as the organism's tendency toward an optimal grip on multiple relevant affordances simultaneously. Affordances are possibilities for action provided by the environment. In the first part of this paper, we introduce the notion of skilled intentionality and the phenomenon of responsiveness to a field of relevant affordances. Second, we use Friston's work on neurodynamics, but embed a very minimal version of his Free Energy Principle in the ecological niche of the animal. Thus amended, this principle is helpful for understanding the embeddedness of neurodynamics within the dynamics of the system “brain-body-landscape of affordances.” Next, we show how we can use this adjusted principle to understand the neurodynamics of selective openness to the environment: interacting action-readiness patterns at multiple timescales contribute to the organism's selective openness to relevant affordances. In the final part of the paper, we emphasize the important role of metastable dynamics in both the brain and the brain-body-environment system for adequate affordance-responsiveness. We exemplify our integrative approach by presenting research on the impact of Deep Brain Stimulation on affordance responsiveness of OCD patients. PMID:25161615

  4. Status of Middle Atmosphere-Climate Models: Results SPARC-GRIPS

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Kodera, Kunihiko

    2003-01-01

    The middle atmosphere is an important component of the climate system, primarily because of the radiative forcing of ozone. Middle atmospheric ozone can change, over long times, because of changes in the abundance of anthropogenic pollutants which catalytically destroy it, and because of the temperature sensitivity of kinetic reaction rates. There is thus a complex interaction between ozone, involving chemical and climatic mechanisms. One question of interest is how ozone will change over the next decades , as the "greenhouse-gas cooling" of the middle atmosphere increases but the concentrations of chlorine species decreases (because of policy changes). concerns the climate biases in current middle atmosphere-climate models, especially their ability to simulate the correct seasonal cycle at high latitudes, and the existence of temperature biases in the global mean. A major obstacle when addressing this question This paper will present a summary of recent results from the "GCM-Reality Intercomparison Project for SPARC" (GRIPS) initiative. A set of middle atmosphere-climate models has been compared, identifying common biases. Mechanisms for these biases are being studied in some detail, including off-line assessments of the radiation transfer codes and coordinated studies of the impacts of gravity wave drag due to sub-grid-scale processes. ensemble of models will be presented, along with numerical experiments undertaken with one or more models, designed to investigate the mechanisms at work in the atmosphere. The discussion will focus on dynamical and radiative mechanisms in the current climate, but implications for coupled ozone chemistry and the future climate will be assessed.

  5. Birth weight, intrauterine growth restriction and nutritional status in childhood in relation to grip strength in adults: from the 1982 Pelotas (Brazil) birth cohort

    PubMed Central

    Bielemann, Renata Moraes; Gigante, Denise Petrucci; Horta, Bernardo Lessa

    2016-01-01

    Objective The aim of this study was to evaluate the association among birth weight, intrauterine growth, and nutritional status in childhood with grip strength in young adults from the 1982 Pelotas (Brazil) birth cohort. Methods In 1982, the hospital live births of Pelotas were followed. In 2012, grip strength was evaluated using a hand dynamometer and the best of the six measurements was used. Birth weight was analyzed as z-score for gestational age according to Williams (1982) curve. Weight-for-age, weight-for-length/height, and length/height-for-age at 2 and 4 y were analyzed in z-scores according to 2006 World Health Organization Child Growth Standards. Lean mass at 30 y was included as possible mediator using the g-computation formula. Results In 2012, 3701 (68.1%) individuals were interviewed and 3470 were included in the present analyses. An increase of 1 z-score in birth weight was associated with an increase of 1.5 kg in grip strength in males (95% confidence interval, 1.1–1.9). Positive effect of birth weight on grip strength was found in females. Grip strength was greater in individuals who were born with appropriate size for gestational age and positively associated with weight- and length/height-for-age z-score at 2 and 4 y of age. A positive association between birth weight and grip strength was only partially mediated by adult lean mass (50% and 33% of total effect in males and females), whereas direct effect of weight at 2 y was found only in males. Conclusions It is suggested that good nutrition in prenatal and early postnatal life has a positive influence on adult muscle strength. The results from birth weight were suggestive of fetal programming on grip strength measurement. PMID:26678603

  6. Upcoming long-duration balloon flight of the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Saint Hilaire, Pascal; Duncan, Nicole A.; Hurford, Gordon J.; Bain, Hazel; Maruca, Bennett A.; Boggs, Steven E.; Zoglauer, Andreas C.; Smith, David; Tajima, Hiroyasu; Amman, Mark S.

    2015-04-01

    We present the status of preparations for the upcoming Antarctic long-duration balloon flight of the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument in December 2015. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 mm. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare.

  7. Deficient Grip Force Control in Schizophrenia: Behavioral and Modeling Evidence for Altered Motor Inhibition and Motor Noise

    PubMed Central

    Teremetz, Maxime; Amado, Isabelle; Bendjemaa, Narjes; Krebs, Marie-Odile; Lindberg, Pavel G.; Maier, Marc A.

    2014-01-01

    Whether upper limb sensorimotor control is affected in schizophrenia and how underlying pathological mechanisms may potentially intervene in these deficits is still being debated. We tested voluntary force control in schizophrenia patients and used a computational model in order to elucidate potential cerebral mechanisms underlying sensorimotor deficits in schizophrenia. A visuomotor grip force-tracking task was performed by 17 medicated and 6 non-medicated patients with schizophrenia (DSM-IV) and by 15 healthy controls. Target forces in the ramp-hold-and-release paradigm were set to 5N and to 10% maximal voluntary grip force. Force trajectory was analyzed by performance measures and Principal Component Analysis (PCA). A computational model incorporating neural control signals was used to replicate the empirically observed motor behavior and to explore underlying neural mechanisms. Grip task performance was significantly lower in medicated and non-medicated schizophrenia patients compared to controls. Three behavioral variables were significantly higher in both patient groups: tracking error (by 50%), coefficient of variation of force (by 57%) and duration of force release (up by 37%). Behavioral performance did not differ between patient groups. Computational simulation successfully replicated these findings and predicted that decreased motor inhibition, together with an increased signal-dependent motor noise, are sufficient to explain the observed motor deficits in patients. PCA also suggested altered motor inhibition as a key factor differentiating patients from control subjects: the principal component representing inhibition correlated with clinical severity. These findings show that schizophrenia affects voluntary sensorimotor control of the hand independent of medication, and suggest that reduced motor inhibition and increased signal-dependent motor noise likely reflect key pathological mechanisms of the sensorimotor deficit. PMID:25369465

  8. Hecate/Grip2a Acts to Reorganize the Cytoskeleton in the Symmetry-Breaking Event of Embryonic Axis Induction

    PubMed Central

    Ge, Xiaoyan; Lyman-Gingerich, Jamie; Holguin, Christiana; Dimitrova, Eva; Abrams, Elliot W.; Gupta, Tripti; Marlow, Florence L.; Yabe, Taijiro; Adler, Anna; Mullins, Mary C.; Pelegri, Francisco

    2014-01-01

    Maternal homozygosity for three independent mutant hecate alleles results in embryos with reduced expression of dorsal organizer genes and defects in the formation of dorsoanterior structures. A positional cloning approach identified all hecate mutations as stop codons affecting the same gene, revealing that hecate encodes the Glutamate receptor interacting protein 2a (Grip2a), a protein containing multiple PDZ domains known to interact with membrane-associated factors including components of the Wnt signaling pathway. We find that grip2a mRNA is localized to the vegetal pole of the oocyte and early embryo, and that during egg activation this mRNA shifts to an off-center vegetal position corresponding to the previously proposed teleost cortical rotation. hecate mutants show defects in the alignment and bundling of microtubules at the vegetal cortex, which result in defects in the asymmetric movement of wnt8a mRNA as well as anchoring of the kinesin-associated cargo adaptor Syntabulin. We also find that, although short-range shifts in vegetal signals are affected in hecate mutant embryos, these mutants exhibit normal long-range, animally directed translocation of cortically injected dorsal beads that occurs in lateral regions of the yolk cortex. Furthermore, we show that such animally-directed movement along the lateral cortex is not restricted to a single arc corresponding to the prospective dorsal region, but occur in multiple meridional arcs even in opposite regions of the embryo. Together, our results reveal a role for Grip2a function in the reorganization and bundling of microtubules at the vegetal cortex to mediate a symmetry-breaking short-range shift corresponding to the teleost cortical rotation. The slight asymmetry achieved by this directed process is subsequently amplified by a general cortical animally-directed transport mechanism that is neither dependent on hecate function nor restricted to the prospective dorsal axis. PMID:24967891

  9. Task-dependent changes of motor cortical network excitability during precision grip compared to isolated finger contraction.

    PubMed

    Kouchtir-Devanne, Nezha; Capaday, Charles; Cassim, François; Derambure, Philippe; Devanne, Hervé

    2012-03-01

    The purpose of this study was to determine whether task-dependent differences in corticospinal pathway excitability occur in going from isolated contractions of the index finger to its coordinated activity with the thumb. Focal transcranial magnetic stimulation (TMS) was used to measure input-output (I/O) curves--a measure of corticospinal pathway excitability--of the contralateral first dorsal interosseus (FDI) muscle in 21 healthy subjects performing two isometric motor tasks: index abduction and precision grip. The level of FDI electromyographic (EMG) activity was kept constant across tasks. The amplitude of the FDI motor evoked potentials (MEPs) and the duration of FDI silent period (SP) were plotted against TMS stimulus intensity and fitted, respectively, to a Boltzmann sigmoidal function. The plateau level of the FDI MEP amplitude I/O curve increased by an average of 40% during the precision grip compared with index abduction. Likewise, the steepness of the curve, as measured by the value of the maximum slope, increased by nearly 70%. By contrast, all I/O curve parameters [plateau, stimulus intensity required to obtain 50% of maximum response (S(50)), and slope] of SP duration were similar between the two tasks. Short- and long-latency intracortical inhibitions (SICI and LICI, respectively) were also measured in each task. Both measures of inhibition decreased during precision grip compared with the isolated contraction. The results demonstrate that the motor cortical circuits controlling index and thumb muscles become functionally coupled when the muscles are used synergistically and this may be due, at least in part, to a decrease of intracortical inhibition and an increase of recurrent excitation.

  10. [Gait speed, grip strength and self-rated health among the elderly: data from the FIBRA Campinas network, São Paulo, Brazil].

    PubMed

    Bez, Joelita Pessoa de Oliveira; Neri, Anita Liberalesso

    2014-08-01

    The article seeks to investigate patterns of performance and relationships between grip strength, gait speed and self-rated health, and investigate the relationships between them, considering the variables of gender, age and family income. This was conducted in a probabilistic sample of community-dwelling elderly aged 65 and over, members of a population study on frailty. A total of 689 elderly people without cognitive deficit suggestive of dementia underwent tests of gait speed and grip strength. Comparisons between groups were based on low, medium and high speed and strength. Self-related health was assessed using a 5-point scale. The males and the younger elderly individuals scored significantly higher on grip strength and gait speed than the female and oldest did; the richest scored higher than the poorest on grip strength and gait speed; females and men aged over 80 had weaker grip strength and lower gait speed; slow gait speed and low income arose as risk factors for a worse health evaluation. Lower muscular strength affects the self-rated assessment of health because it results in a reduction in functional capacity, especially in the presence of poverty and a lack of compensatory factors.

  11. Strength and muscle activities during the toe-gripping action: comparison of ankle angle in the horizontal plane between the sitting upright and standing positions

    PubMed Central

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke

    2016-01-01

    [Purpose] The aim of this study was to investigate whether toe grip strength and muscle activities are affected by the ankle angle in the horizontal plane in the sitting upright and standing positions. [Subjects] The subjects were 16 healthy young women. [Methods] We measured toe grip strength and the maximum voluntary contraction activities of the rectus femoris, biceps femoris, anterior tibialis, and medial head of the gastrocnemius. In addition, we calculated the percent integrated electromyography during foot gripping in 3 different ankle joint positions between the long axis of the foot and the line of progression on the horizontal plane, namely 10° of internal rotation, 0°, and 10° of external rotation. [Results] Two-way analysis of variance revealed significant differences. A significant main effect was observed in the measurement conditions for the percent integrated electromyography of the rectus femoris muscle and long head of the biceps femoris. However, two-way analysis of variance did not reveal any significant difference, and a significant main effect was not observed in toe grip strength. [Conclusion] These findings suggest that exerted toe grip strength is only slightly affected by the ankle angle in the horizontal plane in the sitting upright and standing positions. Therefore, the current measurement positions were shown to be optimal for measurement. PMID:27134399

  12. EMG discharge patterns during human grip movement are task-dependent and not modulated by muscle contraction modes: a transcranial magnetic stimulation (TMS) study.

    PubMed

    Anson, J G; Hasegawa, Y; Kasai, T; Latash, M L; Yahagi, S

    2002-05-03

    Our previous study revealed that, during tonic muscle contraction, remarkable functional differences among intrinsic and extrinsic muscles were observed during two different grip movements, i.e., precision and power grips. To verify whether this evidence is true even under the phasic muscle contraction, magnetic stimulation was delivered over the left scalp while a normal human subject performed phasic precision or power grip responses of the right-hand fingers in a simple reaction time (SRT) paradigm. Magnetic stimulation delivered during the latent period revealed different cortico-motoneuronal excitations between the two grip responses. In particular, the contributions of extensor carpi radialis (ECR) muscle were definitely different between the two grip responses, although motor-evoked potentials (MEPs) of first dorsal interosseous (FDI) prior to, and after EMG onset of movement initiation, were not different. These results were similar to previous results obtained during tonic muscle contraction. Thus, we have concluded that the task-dependent EMG discharge pattern in finger manipulation could not be modulated by muscle contraction modes.

  13. Arbitrary visuomotor mapping in the grip-lift task: dissociation of performance deficits in right and left middle cerebral artery stroke.

    PubMed

    Bensmail, D; Sarfeld, A-S; Ameli, M; Fink, G R; Nowak, D A

    2012-05-17

    The ability to rapidly establish a memory link between arbitrary sensory cues and goal-directed movements is part of our daily motor repertoire. It is unknown if this ability is affected by middle cerebral artery stroke. Eighteen right-handed subjects with a first unilateral middle cerebral artery stroke were studied while performing a precision grip to lift objects of different weights. In a "no cue" condition, a noninformative neutral visual stimulus was presented before each lift, thereby not allowing any judgment about the object weight. In a "cue" condition arbitrary color cues provided advance information about the weight to be lifted in the subsequent trial. Subjects performed both conditions with either hand. During "no cue" trials subjects scaled their grip force according to the weight of the preceding lift, irrespective of the hand performing the lift or the hemisphere affected. The presentation of color cues allowed patients with right hemispheric stroke, but not those with left hemispheric stroke, to scale their grip force according to the weight in the upcoming lift when lifting the weight with the unaffected hand. Color cues did not allow for a predictive scaling of grip force according to the weight of the object to be lifted when lifting with the affected hand, irrespective of the affected hemisphere. These data imply that the ability of visuomotor mapping in the grip-lift task is selectively impaired in the affected hand after right middle cerebral artery stroke, but in both hands after left middle cerebral artery stroke.

  14. Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags.

    PubMed

    Taylor, Erica; Carter, James F; Hill, Jenny C; Morton, Carolyn; Daeid, Niamh Nic; Sleeman, Richard

    2008-05-20

    Plastic bags are frequently used to package drugs, explosives and other contraband. There exists, therefore, a requirement in forensic casework to compare bags found at different locations. This is currently achieved almost exclusively by the use of physical comparisons such as birefringence patterns. This paper discusses some of the advantages and shortcomings of this approach, and presents stable isotope ratio mass spectrometry (IRMS) as a supplementary tool for effecting comparisons of this nature. Carbon and hydrogen isotopic data are presented for sixteen grip-seal plastic bags from a wide range of sources, in order to demonstrate the range of values which is likely to be encountered. Both isotopic and physical comparison (specifically birefringence) techniques are then applied to the analysis of rolls of bags from different manufacturing lots from a leading manufacturer. Both approaches are able to associate bags from a common production batch. IRMS can be applied to small fragments which are not amenable to physical comparisons, and is able to discriminate bags which could be confused using birefringence patterns alone. Similarly, in certain cases birefringence patterns discriminate bags with similar isotopic compositions. The two approaches are therefore complementary. When more than one isotopically distinct region exists within a bag (e.g. the grip-seal is distinct from the body) the ability to discriminate and associate bags is greatly increased.

  15. Development of a global motor rating scale for young children (0-4 years) including eye-hand grip coordination.

    PubMed

    Vaivre-Douret, L; Burnod, Y

    2001-11-01

    A comparative study of the eight motor rating scales available in Western countries demonstrated methodological differences in the choice of items and standardization. We have developed a global motor rating scale that includes items which measure postural-motor, locomotor (PML) and eye-hand grip coordination (EHGC), and which allows the assessment of an average of motor function level (MFL), PML and EHGC development. Scores obtained were used to define the acquisition of motor age based on the skills completed. The items were selected on the basis of the average age at which the function developed in two populations of healthy full-term French infants, followed from birth to 4 months (n = 60) and from 4 months to 4 years (n = 63). Recent French developmental standards (mean age and standard deviation) of acquisition allow the identification of neuro-psychomotor deviations from normal motor behaviour. This includes both static and dynamic motor coordination sequences. Inter-examiner correlations (n = 3) for 15 randomly selected children indicated a coefficient of 0.90. The scale revealed a sequence in the organization of learned postural-motor, locomotor and eye-hand gripping skills which can contribute to the understanding of brain areas implicated in this maturation process.

  16. New results on the relation between tyre-road longitudinal stiffness and maximum available grip for motor car

    NASA Astrophysics Data System (ADS)

    Andrieux, A.; Vandanjon, P. O.; Lengelle, R.; Chabanon, C.

    2010-12-01

    Tyre-road estimation methods have been the objective of many research programmes throughout the world. Most of these methods aim at estimating the friction components such as tyre longitudinal slip rate κ and friction coefficient μ in the contact patch area. In order to estimate the maximum available friction coefficient μmax, these methods generally use a probabilistic relationship between the grip obtained for low tyre excitations (such as constant speed driving) and the grip obtained for high tyre excitations (such as emergency braking manoeuvre). Confirmation or invalidation of this relationship from experimental results is the purpose of this paper. Experiments have been carried out on a reference track including several test boards corresponding to a wide textural spectrum. The main advantage of these experiments lies in the use of a vehicle allowing us to accurately build point-by-point relationship between κ and μ. This relationship has been determined for different tyres and pavement textures. Finally, the curves obtained are analysed to check the validity of the relationship between the current friction coefficient used by the car during normal driving conditions and μmax.

  17. The fusion of gerontology and technology in nursing education: History and demonstration of the Gerontological Informatics Reasoning Project--GRIP.

    PubMed

    Dreher, H Michael; Cornelius, Fran; Draper, Judy; Pitkar, Harshad; Manco, Janet; Song, Il-Yeol

    2006-01-01

    Phase I of our Gerontological Reasoning Informatics Project (GRIP) began in the summer of 2002 when all 37 senior undergraduate nursing students in our accelerated BSN nursing program were given PDAs. These students were oriented to use a digitalized geriatric nursing assessment tool embedded into their PDA in a variety of geriatric clinical agencies. This informatics project was developed to make geriatric nursing more technology oriented and focused on seven modules of geriatric assessment: intellect (I), nutrition (N), self-concept (S), physical activity (P), interpersonal functioning (I), restful sleep (R), and elimination (E)--INSPIRE. Through phase II and now phase III, the GRIP Project has become a major collaboration between the College of Nursing & Health Professions and College of Information Science and Technology at Drexel University. The digitalized geriatric nursing health assessment tool has undergone a second round of reliability and validity testing and is now used to conduct a 20 minute comprehensive geriatric health assessment on the PDA, making our undergraduate gerontology course the most high tech clinical course in our nursing curriculum.

  18. [The use of the cable-grip system in the treatment of winged scapula caused by post-traumatic combined nerve injury: a case report].

    PubMed

    Demirhan, Mehmet; Uysal, Mustafa; Onen, Mehmet

    2002-01-01

    A twenty-three-year-old male patient developed winging of the scapula after a combined nerve injury following a gun-shot. Scapulothoracic arthrodesis was considered in order to relieve the patient's complaints. Stabilization of the scapulothoracic joint was performed using a hitherto undescribed method with the use of a cable-grip system (Doll-Miles Trochanter&Cable Grip System-Howmedica). After a seven-month follow-up, union was accomplished without any malposition; the patient's complaint of pain disappeared, shoulder imbalance was restored with an improvement in shoulder abduction from 70 degrees to 100 degrees and in flexion from 110 degrees to 160 degrees.

  19. Grip Strength Decline and Its Determinants in the Very Old: Longitudinal Findings from the Newcastle 85+ Study

    PubMed Central

    Davies, Karen; Jagger, Carol; Kirkwood, Thomas B. L.; Syddall, Holly E.; Sayer, Avan A.

    2016-01-01

    Background Weak grip strength (GS) is a key component of sarcopenia and frailty and a powerful predictor of mortality, morbidity and disability. Despite increasing interest in understanding GS across the lifespan, little is known about GS decline in the very old (aged ≥85). We examined trajectories of GS in very old adults and identified the determinants. Methods GS (kg) was measured four times over 5 years in 319 men and 526 women participating in the Newcastle 85+ Study. A weak GS sub-cohort was identified as having strength of ≤27 kg (men), and ≤16 kg (women) at baseline and follow-up. Mixed models were used to establish trajectories of GS and associated factors in all participants, men and women, and in those with weak GS. Results Men’s mean grip strength was 24.42 (SD = 6.77) kg, and women’s 13.23 (4.42) kg (p<0.001) at baseline, with mean absolute change of -5.27 (4.90) kg and -3.14 (3.41), respectively (p<0.001) by 5-year follow-up. In the time-only mixed model, men experienced linear annual decline in GS of -1.13 (0.8) kg (β (SE), p<0.001), whilst women’s decline although slower, accelerated by -0.06 (0.02) kg (p = 0.01) over time. In the saturated model, higher baseline physical activity, height, fat-free mass, better self-rated health, and not having arthritis in hand(s) were associated with stronger GS initially in both sexes. Annual GS decline in men and participants with weak GS who were highly physically active was slower by 0.95 and 0.52 kg, respectively compared with inactive counterparts. Conclusion Grip strength decline in the very old followed linear (men) and curvilinear (women) trends. High levels of physical activity were protective of GS loss in men (but not in women) and in those with weak GS. Thus maintaining muscle strength in later life is important to reduce the morbidity and mortality in the very old. PMID:27637107

  20. Light-Absorbing Aerosol during NASA GRIP: Overview of Observations in the Free Troposphere and Associated with Tropical Storm Systems

    NASA Astrophysics Data System (ADS)

    Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C. A.; Craig, L.; Dhaniyala, S.; Dibb, J. E.; Hudgins, C. H.; Ismail, S.; Latham, T.; Nenes, A.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2010-12-01

    Aerosols play a significant role in regulating Earth’s climate. Absorbing aerosols typically constitute a small fraction of ambient particle mass but can contribute significantly to direct and indirect climate forcing depending on size, mixing state, concentration, chemical composition, and vertical and spatial distribution. Aerosols may also significantly affect tropical storm/hurricane dynamics through direct light absorption and activation as cloud nuclei. An extensive suite of instrumentation measuring aerosol chemical, physical, and optical properties was deployed aboard the NASA DC-8 to characterize aerosol during the NASA GRIP (Genesis and Rapid Intensification Processes; August-September 2010) mission. The majority of flight time was spent at high altitude (greater than 9 km) and thus much of the sampling was done in the free troposphere, including extensive sampling in the vicinity of tropical storm systems and more diffuse cirrus clouds. With operations based in Fort Lauderdale, FL and St. Croix, U.S. Virgin Islands, a large geographic region was sampled including much of the Gulf of Mexico and tropical Atlantic Ocean. Observations are reported for light-absorbing carbon aerosol (mainly black carbon, BC) primarily using a single particle soot photometer (SP2). The SP2 employs single-particle laser-induced incandescence to provide a mass-specific measurement not subject to scattering interference that is optimal for the low concentration environments like those encountered during GRIP. BC mass concentrations, 100-500 nm size distributions, and mixing state (i.e. coating thickness of scattering material) are presented. Total and sub-micron aerosol absorption coefficients (principally from BC and dust aerosol) are reported using a particle soot absorption photometer (PSAP) along with comparisons with calculated absorption coefficients derived from SP2 observations in various conditions. In addition, dust aerosol is specifically identified using optical and

  1. Grip force and heart rate responses to manual carrying tasks: effects of material, weight, and base area of the container.

    PubMed

    Lee, Tzu-Hsien; Tseng, Chia-Yun

    2014-01-01

    This study recruited 16 industrial workers to examine the effects of material, weight, and base area of container on reduction of grip force (ΔGF) and heart rate for a 100-m manual carrying task. This study examined 2 carrying materials (iron and water), 4 carrying weights (4.4, 8.9, 13.3, 17.8 kg), and 2 base areas of container (24 × 24 cm, 35 × 24 cm). This study showed that carrying water significantly increased ΔGF and heart rate as compared with carrying iron. Also, ΔGF and heart rate significantly increased with carrying weight and base area of container. The effects of base area of container on ΔGF and heart rate were greater in carrying water condition than in carrying iron condition. The maximum dynamic effect of water on ΔGF and heart rate occurred when water occupied ~60%-80% of full volume of the container.

  2. Meaningful power grip recovery after salvage reconstruction of a median nerve avulsion injury with a pedicled vascularized ulnar nerve

    PubMed Central

    Van Slyke, Aaron C; Jansen, Leigh A; Hynes, Sally; Hicks, Jane; Bristol, Sean; Carr, Nicholas

    2015-01-01

    In cases of median nerve injury alongside an unsalvageable ulnar nerve, a vascularized ulnar nerve graft to reconstruct the median nerve is a viable option. While restoration of median nerve sensation is consistently reported, recovery of significant motor function is less frequently observed. The authors report a case involving a previously healthy man who sustained upper arm segmental median and ulnar nerve injuries and, after failure of sural nerve grafts, was treated with a pedicled vascularized ulnar nerve graft to restore median nerve function. Long-term follow-up showed near full fist, with 12 kg of grip strength, key pinch with 1.5 kg of strength and protective sensation in the median nerve distribution. The present case demonstrates that pedicled ulnar vascularized nerve grafts can provide significant improvements to median nerve sensory and motor function in a heavily scarred environment. PMID:26665144

  3. From Single Motor Unit Activity to Multiple Grip Forces: Mini‐review of Multi‐digit Grasping1

    PubMed Central

    Winges, Sara A.; Santello, Marco

    2007-01-01

    SYNOPSIS This paper is a mini review of kinetic and kinematic evidence on the control of the hand with emphasis on grasping. It is not meant to be an exhaustive review, rather it summarizes current research examining the mechanisms through which specific patterns of coordination are elicited and observed during reach to grasp movements and static grasping. These coordination patterns include the spatial and temporal covariation of the rotation at multiple joints during reach to grasp movements. A basic coordination between grip forces produced by multiple digits also occurs during whole hand grasping such that normal forces tend to be produced in a synchronous fashion across pairs of digits. Finally, we address current research that suggests that motor unit synchrony across hand muscles and muscle compartments might be one of the neural mechanisms underlying the control of grasping. PMID:18414593

  4. Maximal dynamic grip force and wrist torque: the effects of gender, exertion direction, angular velocity, and wrist angle.

    PubMed

    Morse, Jonathan L; Jung, Myung-Chul; Bashford, Gregory R; Hallbeck, M Susan

    2006-11-01

    The objective of this study was to examine the effects of gender, exertion direction, angular velocity and wrist angle on simultaneous grip force and wrist torque under the isokinetic condition. The study used 20 participants (10 males and 10 females) and included 6 angular velocities (15, 30, 45, 60, 75, and 90 degrees /s) and 2 wrist exertion directions (flexion and extension) over the wrist range of motion of 70 degrees flexion to 60 degrees extension in 5 degrees increments. Similar to other studies, males and flexion exertion produced larger forces than females and extension exertion, respectively. However, the largest forces were generated at near extreme flexion of the wrist and the dependent variable of angular velocity was not practically significant. These results can contribute to the evaluation of cumulative trauma syndromes, but there is a need for more research on the dynamic measures of the hand and wrist complex and for standard development for dynamic force measurement.

  5. Description of Primary Education 1st Grade Students' Forms of Holding a Pencil as well as Their Grip and Compression Strengths

    ERIC Educational Resources Information Center

    Temur, Turan

    2011-01-01

    This study aimed to examine how first grade students in primary education held and gripped a pencil and their compressive strength using a descriptive research method. The participants of the research comprises first grade students attending a private school in the city center of Ankara (n=79). All of the four different sections in this private…

  6. Relationship between grip strength and newly diagnosed nonalcoholic fatty liver disease in a large-scale adult population

    PubMed Central

    Meng, Ge; Wu, Hongmei; Fang, Liyun; Li, Chunlei; Yu, Fei; Zhang, Qing; Liu, Li; Du, Huanmin; Shi, Hongbin; Xia, Yang; Guo, Xiaoyan; Liu, Xing; Bao, Xue; Su, Qian; Gu, Yeqing; Yang, Huijun; Bin Yu; Wu, Yuntang; Sun, Zhong; Niu, Kaijun

    2016-01-01

    Enhanced muscle strength is often related to improved insulin sensitivity and secretion, control of lipid metabolism, and increased secretion of myokines. These factors have emerged as important mechanisms involved in the development and progression of nonalcoholic fatty liver disease (NAFLD), implying that muscle strength may be a useful predictor for NAFLD. We aimed to assess the relationship between grip strength (GS) and NAFLD in a large-scale adult population. GS was assessed using an electronic hand-grip dynamometer, and NAFLD was diagnosed by the liver ultrasonography. Multiple logistic regression analysis was used to assess the relationship between the quartiles of GS per body weight and the prevalence of NAFLD. After adjusting for potentially confounding factors, the odds ratios (95% confidence interval) for overall NAFLD, NAFLD with normal alanine aminotransferase levels, and NAFLD with elevated alanine aminotransferase levels across the quartiles of GS were 1.00 (reference), 0.89 (0.78, 1.01), 0.77 (0.67, 0.89), and 0.67 (0.57, 0.79); 1.00 (reference), 0.91 (0.80, 1.04), 0.79 (0.68, 0.92), and 0.72 (0.61, 0.85); 1.00 (reference), 0.77 (0.61, 0.98), 0.67 (0.51, 0.86), and 0.53 (0.40, 0.71) (all P for trend < 0.01), respectively. This is the first study shows that increased GS is independently associated with lower prevalence of NAFLD. PMID:27616599

  7. Microscopic vision modeling method by direct mapping analysis for micro-gripping system with stereo light microscope.

    PubMed

    Wang, Yuezong; Zhao, Zhizhong; Wang, Junshuai

    2016-04-01

    We present a novel and high-precision microscopic vision modeling method, which can be used for 3D data reconstruction in micro-gripping system with stereo light microscope. This method consists of four parts: image distortion correction, disparity distortion correction, initial vision model and residual compensation model. First, the method of image distortion correction is proposed. Image data required by image distortion correction comes from stereo images of calibration sample. The geometric features of image distortions can be predicted though the shape deformation of lines constructed by grid points in stereo images. Linear and polynomial fitting methods are applied to correct image distortions. Second, shape deformation features of disparity distribution are discussed. The method of disparity distortion correction is proposed. Polynomial fitting method is applied to correct disparity distortion. Third, a microscopic vision model is derived, which consists of two models, i.e., initial vision model and residual compensation model. We derive initial vision model by the analysis of direct mapping relationship between object and image points. Residual compensation model is derived based on the residual analysis of initial vision model. The results show that with maximum reconstruction distance of 4.1mm in X direction, 2.9mm in Y direction and 2.25mm in Z direction, our model achieves a precision of 0.01mm in X and Y directions and 0.015mm in Z direction. Comparison of our model with traditional pinhole camera model shows that two kinds of models have a similar reconstruction precision of X coordinates. However, traditional pinhole camera model has a lower precision of Y and Z coordinates than our model. The method proposed in this paper is very helpful for the micro-gripping system based on SLM microscopic vision.

  8. Normative data for hand grip strength and key pinch strength, stratified by age and gender for a multiethnic Asian population

    PubMed Central

    Lam, Ngee Wei; Goh, Hui Ting; Kamaruzzaman, Shahrul Bahyah; Chin, Ai-Vyrn; Poi, Philip Jun Hua; Tan, Maw Pin

    2016-01-01

    INTRODUCTION Hand strength is a good indicator of physical fitness and frailty among the elderly. However, there are no published hand strength references for Malaysians aged > 65 years. This study aimed to establish normative data for hand grip strength (HGS) and key pinch strength (KPS) for Malaysians aged ≥ 60 years, and explore the relationship between hand strength and physical ability. METHODS Healthy participants aged ≥ 60 years with no neurological conditions were recruited from rural and urban locations in Malaysia. HGS and KPS were measured using hand grip and key pinch dynamometers. Basic demographic data, anthropometric measures, modified Barthel Index scores and results of the Functional Reach Test (FRT), Timed Up and Go (TUG) test and Jebsen-Taylor Hand Function Test (JTHFT) were recorded. RESULTS 362 subjects aged 60–93 years were recruited. The men were significantly stronger than the women in both HGS and KPS (p < 0.001). The hand strength of the study cohort was lower than that of elderly Western populations. Significant correlations were observed between hand strength, and residential area (p < 0.001), FRT (r = 0.236, p = 0.028), TUG (r = −0.227, p = 0.009) and JTHFT (r = −0.927, p < 0.001). CONCLUSION This study established reference ranges for the HGS and KPS of rural and urban elderly Malaysian subpopulations. These will aid the use of hand strength as a screening tool for frailty among elderly persons in Malaysia. Future studies are required to determine the modifiable factors for poor hand strength. PMID:26768064

  9. Muscle-Pair Specific Distribution and Grip-Type Modulation of Neural Common Input to Extrinsic Digit Flexors

    PubMed Central

    Winges, Sara A.; Johnston, Jamie A.; Santello, Marco

    2007-01-01

    To gain insight into the synergistic control of hand muscles, we have recently quantified the strength of correlated neural activity across motor units from extrinsic digit flexors during a five-digit object-hold task. We found stronger synchrony and coherence across motor units from thumb and index finger flexor muscle compartment than between the thumb flexor and other finger flexor muscle compartments. The present study of two-digit object hold was designed to determine the extent to which such distribution of common input among thumb-finger flexor muscle compartments, revealed by holding an object with five digits, is preserved when varying the functional role of a given digit pair. We recorded normal force exerted by the digits and electrical activity of single motor units from muscle flexor pollicis longus (FPL) and two compartments of the m. flexor digitorum profundus (FDP2 and FDP3; index and middle finger, respectively). Consistent with our previous results from five-digit grasping, synchrony and coherence across motor units from FPL-FDP2 was significantly stronger than in FPL-FDP3 during object hold with two digits [common input strength: 0.49 ± 0.02 and 0.35 ± 0.02 (means ± SE), respectively; peak coherence: 0.0054 and 0.0038, respectively]. This suggests that the distribution of common neural input is muscle-pair specific regardless of grip type. However, the strength of coherence, but not synchrony, was significantly stronger in two- versus five-digit object hold for both muscle combinations, suggesting the periodicity of common input is sensitive to grip type. PMID:16723414

  10. Tongue Strength is Associated with Grip Strength and Nutritional Status in Older Adult Inpatients of a Rehabilitation Hospital.

    PubMed

    Sakai, Kotomi; Nakayama, Enri; Tohara, Haruka; Maeda, Tomomi; Sugimoto, Motonobu; Takehisa, Takahiro; Takehisa, Yozo; Ueda, Koichiro

    2017-04-01

    The aim of this cross-sectional study was to investigate whether tongue strength observed in older adult inpatients of a rehabilitation hospital is associated with muscle function, nutritional status, and dysphagia. A total of 174 older adult inpatients aged 65 years and older in rehabilitation (64 men, 110 women; median age, 84 years; interquartile range, 80-89 years) who were suspected of having reduced tongue strength due to sarcopenia were included in this study. Isometric tongue strength was measured using a device fitted with a disposable oral balloon probe. We evaluated age, muscle function as assessed by the Barthel index and grip strength, nutritional status as measured by the Mini Nutritional Assessment-short form (MNA-SF), body mass index, serum albumin, controlling nutritional status, and calf circumference and arm muscle area to assess muscle mass. In addition, the functional oral intake scale (FOIS) was used as an index of dysphagia. Multivariate linear regression analysis revealed that isometric tongue strength was independently associated with grip strength (coefficient = 0.33, 95 % confidence interval (CI) 0.12-0.54, p = 0.002), MNA-SF (coefficient = 0.74, 95 % CI 0.12-1.35, p = 0.019), and FOIS (coefficient = 0.02, 95 % CI 0.00-0.15, p = 0.047). To maintain and improve tongue strength in association with sarcopenic dysphagia, exercise therapy and nutritional therapy interventions, as well as direct interventions to address tongue strength, may be effective in dysphagia rehabilitation in older adult inpatients.

  11. Combining displacement field and grip force information to determine mechanical properties of planar tissue with complicated geometry.

    PubMed

    Nagel, Tina M; Hadi, Mohammad F; Claeson, Amy A; Nuckley, David J; Barocas, Victor H

    2014-11-01

    Performing planar biaxial testing and using nominal stress-strain curves for soft-tissue characterization is most suitable when (1) the test produces homogeneous strain fields, (2) fibers are aligned with the coordinate axes, and (3) strains are measured far from boundaries. Some tissue types [such as lamellae of the annulus fibrosus (AF)] may not allow for these conditions to be met due to their natural geometry and constitution. The objective of this work was to develop and test a method utilizing a surface displacement field, grip force-stretch data, and finite-element (FE) modeling to facilitate analysis of such complex samples. We evaluated the method by regressing a simple structural model to simulated and experimental data. Three different tissues with different characteristics were used: Superficial pectoralis major (SPM) (anisotropic, aligned with axes), facet capsular ligament (FCL) (anisotropic, aligned with axes, bone attached), and a lamella from the AF (anisotropic, aligned off-axis, bone attached). We found that the surface displacement field or the grip force-stretch data information alone is insufficient to determine a unique parameter set. Utilizing both data types provided tight confidence regions (CRs) of the regressed parameters and low parameter sensitivity to initial guess. This combined fitting approach provided robust characterization of tissues with varying fiber orientations and boundaries and is applicable to tissues that are poorly suited to standard biaxial testing. The structural model, a set of C++ finite-element routines, and a Matlab routine to do the fitting based on a set of force/displacement data is provided in the on-line supplementary material.

  12. Dynamometry for the measurement of grip, pinch, and trunk muscles strength in subjects with subacute stroke: reliability and different number of trials

    PubMed Central

    Aguiar, Larissa T.; Martins, Júlia C.; Lara, Eliza M.; Albuquerque, Julianna A.; Teixeira-Salmela, Luci F.; Faria, Christina D. C. M.

    2016-01-01

    ABSTRACT Background Muscle strength is usually measured in individuals with stroke with Portable dynamometers (gold standard). However, no studies have investigated the reliability, the standard error of measurement (SEM) and the minimal detectable difference (MDD95%) of the dynamometry for the measurement of hand grip, pinch grip and trunk strength in subjects with subacute stroke. Objective 1) To investigate the intra and inter-rater reliability, the SEM and the MDD95% of the portable dynamometers for the measurement of grip, pinch and trunk strength in subjects with subacute stroke, and 2) to verify whether the use of different number of trials (first trial and the average of the first two and three trials) affected the results. Method 32 subjects with subacute stroke (time since stroke onset: 3.6 months, SD=0.66 months) were evaluated. Hand grip, 3 pinch grips (i.e. pulp-to-pulp/palmar/lateral) and 4 trunk muscles (i.e. flexors, extensors, lateral flexors and rotators) strength were bilaterally assessed (except trunk flexors/extensors) with portable dynamometry by two independent examiners over two sessions (1-2 weeks apart). One-way ANOVAs and intraclass correlation coefficients (ICC2,k) were used for analysis (α=0.05). SEM and MDD95% were also calculated. Results For all muscular groups and sources of outcome values, including one trial, after familiarization, similar results were found (0.01≤F≤0.08; 0.92≤p≤0.99) with significant and adequate values of intra-rater (0.64≤ICC≤0.99; 0.23≤95%CI≤0.99) and inter-rater (0.66≤ICC≤0.99; 0.25≤95%CI≤0.99) reliability. SEM and MDD95% were considered low (0.39≤EPM≤2.21 Kg; 0.96≤MMD95%≤6.12 Kg) for all outcome scores. Conclusion Only one trial, following familiarization, demonstrated adequate intra-rater and inter-rater reliability of the portable dynamometers for the measurement of hand grip, pinch grip and trunk strength in subjects with subacute stroke. PMID:27410161

  13. Coordination of precision grip in 2–6 years-old children with autism spectrum disorders compared to children developing typically and children with developmental disabilities

    PubMed Central

    David, Fabian J.; Baranek, Grace T.; Wiesen, Chris; Miao, Adrienne F.; Thorpe, Deborah E.

    2012-01-01

    Impaired motor coordination is prevalent in children with Autism Spectrum Disorders (ASD) and affects adaptive skills. Little is known about the development of motor patterns in young children with ASD between 2 and 6 years of age. The purpose of the current study was threefold: (1) to describe developmental correlates of motor coordination in children with ASD, (2) to identify the extent to which motor coordination deficits are unique to ASD by using a control group of children with other developmental disabilities (DD), and (3) to determine the association between motor coordination variables and functional fine motor skills. Twenty-four children with ASD were compared to 30 children with typical development (TD) and 11 children with DD. A precision grip task was used to quantify and analyze motor coordination. The motor coordination variables were two temporal variables (grip to load force onset latency and time to peak grip force) and two force variables (grip force at onset of load force and peak grip force). Functional motor skills were assessed using the Fine Motor Age Equivalents of the Vineland Adaptive Behavior Scale and the Mullen Scales of Early Learning. Mixed regression models were used for all analyses. Children with ASD presented with significant motor coordination deficits only on the two temporal variables, and these variables differentiated children with ASD from the children with TD, but not from children with DD. Fine motor functional skills had no statistically significant associations with any of the motor coordination variables. These findings suggest that subtle problems in the timing of motor actions, possibly related to maturational delays in anticipatory feed-forward mechanisms, may underlie some motor deficits reported in children with ASD, but that these issues are not unique to this population. Further research is needed to investigate how children with ASD or DD compensate for motor control deficits to establish functional skills

  14. Additional considerations and recommendations for the quantification of hand-grip strength in the measurement of leg power during high-intensity cycle ergometry.

    PubMed

    Baker, Julien Steven; Davies, Bruce

    2009-01-01

    The purpose of this study was to further examine the influence of hand-grip strength on power profiles and blood lactate values during high-intensity cycle ergometry. Fifteen male subjects each completed a 20-second cycle ergometer test twice, in a random manner, using two protocols, with a hand grip (WG), and without hand grip (WOHG). Hand-grip strength was quantified prior to exercise using a hand-grip dynamometer. Capillary (earlobe) blood was collected at rest, immediately following exercise, and 5 minutes postexercise. In the WG protocol, mean (+/-SD) blood lactate concentrations were 1.11 +/- 0.7 mmol.l( -1), 3.68 +/- 1.2 mmol.l( -1), and 8.14 +/- 1.3 mmol.l( -1), respectively. During the WOHG protocol, blood lactate values recorded were 0.99 +/- 0.9 mmol.l( -1), 3.68 +/- 1.1 mmol.l( -1), and 6.62 +/- 0.9 mmol.l( -1), respectively. Differences in lactate concentrations were found (P < 0.05) from rest to 5 minutes postexercise for both groups. Differences in concentrations also were observed between groups at the 5-minutes postexercise stage. Peak power output and fatigue index values also were greater using the WG protocol (792 +/- 73 W vs. 624 +/- 66 W; 38 +/- 6 vs. 24 +/- 8 W respectively; P< 0.05). No differences were recorded for mean power output (MPO) or work done (WD) between experimental conditions. These findings suggest that the performance of traditional style leg cycle ergometry is influenced by a muscular contribution from the upper body and by upper body strength.

  15. The Effect of Hand Dimensions, Hand Shape and Some Anthropometric Characteristics on Handgrip Strength in Male Grip Athletes and Non-Athletes

    PubMed Central

    Fallahi, Ali Asghar; Jadidian, Ali Akbar

    2011-01-01

    It has been suggested that athletes with longer fingers and larger hand surfaces enjoy stronger grip power. Therefore, some researchers have examined a number of factors and anthropometric variables that explain this issue. To our knowledge, the data is scarce. Thus, the aim of this study was to investigate the effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes. 80 subjects aged between 19 and 29 participated in this study in two groups including: national and collegian grip athletes (n=40), and non-athletes (n=40). Body height and mass were measured to calculate body mass index. The shape of the dominant hand was drawn on a piece of paper with a thin marker so that finger spans, finger lengths, and perimeters of the hand could be measured. The hand shape was estimated as the ratio of the hand width to hand length. Handgrip strength was measured in the dominant and non-dominant hand using a standard dynamometer. Descriptive statistics were used for each variable and independent t test was used to analyze the differences between the two groups. The Pearson correlation coefficient test was used to evaluate the correlation between studied variables. Also, to predict important variables in handgrip strength, the linear trend was assessed using a linear regression analysis. There was a significant difference between the two groups in absolute handgrip strength (p<0.001) and handgrip/height ratio (p<0.001). The indices of body height, body mass, lean body mass and body fat content (p<0.001) were significantly greater in grip athletes. All hand variables except FS1-4 (p>0.05) were significantly different between the groups (p<0.001). After controlling body mass all hand anthropometric characteristics except thumb length (r=0.240, p= 0.135), hand shape (r=−0.029, p=0.858), middle finger length (r=0.305, p=0.056) and forearm circumference (r=0.162, p=0.319) significantly correlated with

  16. The Effectiveness of Manual Therapy Versus Surgery on Self-reported Function, Cervical Range of Motion, and Pinch Grip Force in Carpal Tunnel Syndrome: A Randomized Clinical Trial.

    PubMed

    Fernández-de-Las-Peñas, César; Cleland, Joshua; Palacios-Ceña, María; Fuensalida-Novo, Stella; Pareja, Juan A; Alonso-Blanco, Cristina

    2017-03-01

    Study Design Randomized parallel-group trial. Background Carpal tunnel syndrome (CTS) is a common pain condition that can be managed surgically or conservatively. Objective To compare the effectiveness of manual therapy versus surgery for improving self-reported function, cervical range of motion, and pinch-tip grip force in women with CTS. Methods In this randomized clinical trial, 100 women with CTS were randomly allocated to either a manual therapy (n = 50) or a surgery (n = 50) group. The primary outcome was self-rated hand function, assessed with the Boston Carpal Tunnel Questionnaire. Secondary outcomes included active cervical range of motion, pinch-tip grip force, and the symptom severity subscale of the Boston Carpal Tunnel Questionnaire. Patients were assessed at baseline and 1, 3, 6, and 12 months after the last treatment by an assessor unaware of group assignment. Analysis was by intention to treat, with mixed analyses of covariance adjusted for baseline scores. Results At 12 months, 94 women completed the follow-up. Analyses showed statistically significant differences in favor of manual therapy at 1 month for self-reported function (mean change, -0.8; 95% confidence interval [CI]: -1.1, -0.5) and pinch-tip grip force on the symptomatic side (thumb-index finger: mean change, 2.0; 95% CI: 1.1, 2.9 and thumb-little finger: mean change, 1.0; 95% CI: 0.5, 1.5). Improvements in self-reported function and pinch grip force were similar between the groups at 3, 6, and 12 months. Both groups reported improvements in symptom severity that were not significantly different at all follow-up periods. No significant changes were observed in pinch-tip grip force on the less symptomatic side and in cervical range of motion in either group. Conclusion Manual therapy and surgery had similar effectiveness for improving self-reported function, symptom severity, and pinch-tip grip force on the symptomatic hand in women with CTS. Neither manual therapy nor surgery resulted

  17. The effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes.

    PubMed

    Fallahi, Ali Asghar; Jadidian, Ali Akbar

    2011-09-01

    It has been suggested that athletes with longer fingers and larger hand surfaces enjoy stronger grip power. Therefore, some researchers have examined a number of factors and anthropometric variables that explain this issue. To our knowledge, the data is scarce. Thus, the aim of this study was to investigate the effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes. 80 subjects aged between 19 and 29 participated in this study in two groups including: national and collegian grip athletes (n=40), and non-athletes (n=40). Body height and mass were measured to calculate body mass index. The shape of the dominant hand was drawn on a piece of paper with a thin marker so that finger spans, finger lengths, and perimeters of the hand could be measured. The hand shape was estimated as the ratio of the hand width to hand length. Handgrip strength was measured in the dominant and non-dominant hand using a standard dynamometer. Descriptive statistics were used for each variable and independent t test was used to analyze the differences between the two groups. The Pearson correlation coefficient test was used to evaluate the correlation between studied variables. Also, to predict important variables in handgrip strength, the linear trend was assessed using a linear regression analysis. There was a significant difference between the two groups in absolute handgrip strength (p<0.001) and handgrip/height ratio (p<0.001). The indices of body height, body mass, lean body mass and body fat content (p<0.001) were significantly greater in grip athletes. All hand variables except FS1-4 (p>0.05) were significantly different between the groups (p<0.001). After controlling body mass all hand anthropometric characteristics except thumb length (r=0.240, p= 0.135), hand shape (r=-0.029, p=0.858), middle finger length (r=0.305, p=0.056) and forearm circumference (r=0.162, p=0.319) significantly correlated with

  18. The effects of instruction and hand dominance on grip-to-load force coordination in manipulation tasks.

    PubMed

    Jin, Xin; Uygur, Mehmet; Getchell, Nancy; Hall, Susan J; Jaric, Slobodan

    2011-10-31

    The force applied upon a vertically oriented hand-held object could be decomposed into two orthogonal and highly coordinated components: the grip force (GF; the component perpendicular to the hand-object contact area that provides friction) and the load force (LF; the parallel component that can move the object or support the body). The aim of this study was to investigate the underexplored effects of task instruction and hand dominance on GF-LF coordination. Sixteen right-handed subjects performed bimanual manipulation against a horizontally oriented instrumented device under different sets of instructions. The tasks involved exertion of ramp-and-hold or oscillation patterns of LF performed symmetrically with two hands, while the instructions regarding individual actions were either similar (pull with both hands) or dissimilar (pull with one hand and hold with another). The results revealed that the instruction "to pull" leads to higher indices of GF-LF coordination than the instruction "to hold", as evidenced by a lower GF-LF ratio, higher GF-LF coupling, and higher GF modulation. The only effect of hand dominance was a moderate time lag of GF relative to LF changes observed in the non-dominant hand. We conclude that the instructions could play an important role in GF-LF coordination and, therefore, they should be taken into account when exploring or routinely testing hand function. Additionally, the results suggest that the neural control of GF of the non-dominant hand could involve some feedback mechanisms.

  19. Degree, but not direction of grip strength asymmetries, is related to depression and anxiety in an elderly population.

    PubMed

    Yu, Junhong; Rawtaer, Iris; Mahendran, Rathi; Kua, Ee-Heok; Feng, Lei

    2017-05-01

    Despite the abundance of studies on asymmetries in manual laterality, a marker for atypical brain lateralization in depression and anxiety, findings in this area are mixed. Traditionally, research have looked at individual differences in depression and anxiety as a function of the direction of asymmetry. However, recent research has emphasized on studying the degree of asymmetry in addition to its direction. To these ends, the present study aims to unravel the associations between the degree and direction of manual lateralization, and depression/anxiety. Cognitively healthy elderlies (N = 326, 91 males, Mage = 68) were administered grip strength assessments on both hands and self-report measures of depression and anxiety. Partial correlation analyses controlling for age, education and sex revealed significant positive associations between degree of lateralization and anxiety in the overall sample and among right-dominant participants, as well as a significant positive relationship between degree of lateralization and depression among right-dominant participants. None of the correlations involving the direction of lateralization yielded significance, neither was there significant differences between left- and right-dominant participants on depression and anxiety scores. These findings suggest that the degree of manual lateralization, but not direction, is related to depression and anxiety at least among right-dominant individuals.

  20. Losing grip: Senescent decline in physical strength in a small-bodied primate in captivity and in the wild.

    PubMed

    Hämäläinen, Anni; Dammhahn, Melanie; Aujard, Fabienne; Kraus, Cornelia

    2015-01-01

    Muscle strength reflects physical functioning, declines at old age and predicts health and survival in humans and laboratory animals. Age-associated muscle deterioration causes loss of strength and may impair fitness of wild animals. However, the effects of age and life-history characteristics on muscle strength in wild animals are unknown. We investigated environment- and sex-specific patterns of physical functioning by measuring grip strength in wild and captive gray mouse lemurs. We expected more pronounced strength senescence in captivity due to condition-dependent, extrinsic mortality found in nature. Males were predicted to be stronger but potentially experience more severe senescence than females as predicted by life history theory. We found similar senescent declines in captive males and females as well as wild females, whereas wild males showed little decline, presumably due to their early mortality. Captive animals were generally weaker and showed earlier declines than wild animals. Unexpectedly, females tended to be stronger than males, especially in the reproductive season. Universal intrinsic mechanisms (e.g. sarcopenia) likely cause the similar patterns of strength loss across settings. The female advantage in muscle strength merits further study; it may follow higher reproductive investment by males, or be an adaptation associated with female social dominance.

  1. The relationship between grip strength and muscle mass (MM), inflammatory biomarkers and physical performance in community-dwelling very old persons.

    PubMed

    Legrand, D; Adriaensen, W; Vaes, B; Matheï, C; Wallemacq, P; Degryse, J

    2013-01-01

    The main consequence of the loss of MM and muscle strength is limitations of physical performance and disability in older people. It is unclear whether a decline in functional capacity results from the loss of MM and/or the qualitative impairment of the muscle tissue. The aim of our research was to investigate the relationship between physical performance and grip strength, inflammatory markers and MM in a population of community-dwelling very old persons. This study is a cross-sectional analysis within the BELFRAIL-study, a cohort study of subjects aged 80 years and older (n=567). MM was assessed by bioelectrical impedance. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations were determined on fasting blood samples. Logistic regression analysis was build using a low physical performance level evaluated according to Short Physical Performance Battery (SPPB) (dependent variable) and grip strength, pro-inflammatory status and MM (independent variables) adjusted for age and for the total number of chronic diseases. Low SPPB scores were associated with grip strength scores for women (OR 0.86 (95% CI 0.77-0.96)), and for men (OR 0.89 (95% CI 0.81-0.96)). The relationships between low SPPB and MM or inflammatory profile were not significant. Our results show that low physical performance remains associated with low grip strength even after considering other risk factors for sarcopenia in the oldest old and support the hypothesis that low muscle strength is a better indicator than low MM. The role of an inflammatory component in the age-related loss of muscle strength and function could not be confirmed.

  2. Human parietal and primary motor cortical interactions are selectively modulated during the transport and grip formation of goal-directed hand actions.

    PubMed

    Vesia, Michael; Bolton, David A; Mochizuki, George; Staines, W R

    2013-02-01

    Posterior parietal cortex (PPC) constitutes a critical cortical node in the sensorimotor system in which goal-directed actions are computed. This information then must be transferred into commands suitable for hand movements to the primary motor cortex (M1). Complexity arises because reach-to-grasp actions not only require directing the hand towards the object (transport component), but also preshaping the hand according to the features of the object (grip component). Yet, the functional influence that specific PPC regions exert over ipsilateral M1 during the planning of different hand movements remains unclear in humans. Here we manipulated transport and grip components of goal-directed hand movements and exploited paired-pulse transcranial magnetic stimulation ((pp)TMS) to probe the functional interactions between M1 and two different PPC regions, namely superior parieto-occipital cortex (SPOC) and the anterior region of the intraparietal sulcus (aIPS), in the left hemisphere. We show that when the extension of the arm is required to contact a target object, SPOC selectively facilitates motor evoked potentials, suggesting that SPOC-M1 interactions are functionally specific to arm transport. In contrast, a different pathway, linking the aIPS and ipsilateral M1, shows enhanced functional connections during the sensorimotor planning of grip. These results support recent human neuroimaging findings arguing for specialized human parietal regions for the planning of arm transport and hand grip during goal-directed actions. Importantly, they provide new insight into the causal influences these different parietal regions exert over ipsilateral motor cortex for specific types of planned hand movements.

  3. The value of grip test, lysophosphatidlycholines, glycerophosphocholine, ornithine, glucuronic acid decrement in assessment of nutritional and metabolic characteristics in hepatitis B cirrhosis.

    PubMed

    Ye, Qing; Yin, Weili; Zhang, Lei; Xiao, Huijuan; Qi, Yumei; Liu, Shuye; Qian, Baoxin; Wang, Fengmei; Han, Tao

    2017-01-01

    The liver is essential for the regulation of energy, protein and amino acids, as well as in other aspects of metabolism. To identify efficient indexes for evaluation of nutritional status and metabolic characteristics during different Child-Pugh stages of hepatitis B cirrhosis, 83 patients and 35 healthy individuals were enrolled in our study. We found that grip strength, triceps skinfold thickness (TSF), body fat and skeletal muscle of the patients were reduced compared to the control group (P<0.05). Ultra-high-performance liquid chromatography data combined with mass spectrometry (UPLC-MS) showed that levels of a variety of metabolites, including lysophosphatidylcholines (LysoPCs), glycerophosphocholine, ornithine and glucuronic acid were reduced in the serum of patients with hepatitis B cirrhosis (P<0.001). However, glycerophosphoserine and taurocholic acid levels were higher than in the control group (P<0.001). Moreover, grip strength was correlated with the Child-Pugh score (P<0.05). Serum albumin, total cholesterol, LDL, LysoPCs, glycerophosphocholine, ornithine, glucuronic acid, glycerophosphoserine and taurocholic acid were correlated with the Child-Pugh score (P<0.01). These findings suggested that grip strength and the above small molecular substances might be considered as sensitive and important indexes for evaluating nutritional status and metabolic characteristics of patients with hepatitis B cirrhosis, which may help assess prognosis and adjust nutritional treatment.

  4. Reference Values of Grip Strength Measured with a Jamar Dynamometer in 1526 Adults with Intellectual Disabilities and Compared to Adults without Intellectual Disability

    PubMed Central

    Cuesta-Vargas, Antonio; Hilgenkamp, Thessa

    2015-01-01

    Aim The aim of this study was to investigate grip strength in a large sample of people with intellectual disabilities, to establish reference values for adults with intellectual disabilities (ID) and compare it to adults without intellectual disability. Methods This study analysed pooled baseline data from two independent studies for all 1526 adults with ID: Special Olympics Funfitness Spain (n = 801) and the Dutch cross-sectional study ‘Healthy aging and intellectual disabilities’ (n = 725). Results The grip strength result of people with ID across gender and age subgroups is presented with CI95% values from higher 25.5–31.0 kg in male younger to lower 4.3–21.6 kg in female older. Conclusion This study is the first to present grip strength results of a large sample of people with ID from 20–90 years of age. This study provides reference values for people with ID for use in clinical practice. PMID:26053852

  5. Changes in Pain, Dysfunction, and Grip Strength of Patients with Acute Lateral Epicondylitis Caused by Frequency of Physical Therapy: A Randomized Controlled Trial

    PubMed Central

    Lee, Soyoung; Ko, Youngjun; Lee, Wanhee

    2014-01-01

    [Purpose] The purpose of this study was to investigate the changes in pain, dysfunction, and grip strength of patients with acute lateral epicondylitis and to suggest the appropriate treatment frequency and period. [Subjects] The subjects were divided into three: 2 days per week group (n=12), 3 days per week group (n=15), and 6 days per week group (n=13). [Methods] All groups received conventional physical therapy for 40 minutes and therapeutic exercises for 20 minutes per session during 6 weeks. The outcome measurements were the visual analogue scale (VAS), Patient-Rated Tennis Elbow Evaluation (PRTEE), and grip strength. [Results] The results of this study were as follows: at 3 weeks, there were no significant differences in VAS and PRTEE in the 3 groups, but at 6 weeks, 6 days per week group significantly decreased these two outcomes. Grip strength was significantly increased in 3 and 6 days per week groups at 6 weeks. [Conclusion] In conclusion, physical therapy is needed 3 days per week for 3 weeks in patients with acute lateral epicondylitis. After 3 weeks, 6 days per week is the most effective treatment frequency. PMID:25140091

  6. EMG activity of finger flexor muscles and grip force following low-dose transcutaneous electrical nerve stimulation in healthy adult subjects.

    PubMed

    Kafri, Michal; Zaltsberg, Nir; Dickstein, Ruth

    2015-01-01

    Somatosensory stimulation modulates cortical and corticospinal excitability and consequently affects motor output. Therefore, low-amplitude transcutaneous electrical nerve stimulation (TENS) has the potential to elicit favorable motor responses. The purpose of the two presented pilot studies was to shed light on TENS parameters that are relevant for the enhancement of two desirable motor outcomes, namely, electromyographic (EMG) activity and contraction strength of the finger flexors and wrist muscles. In 5 and 10 healthy young adults (in Study I and Study II, respectively) TENS was delivered to the volar aspect of the forearm. We manipulated TENS frequency (150 Hz vs. 5 Hz), length of application (10, 20, and 60 min), and side of application (unilateral, right forearm vs. bilateral forearms). EMG amplitude and grip force were measured before (Pre), immediately after (Post), and following 15 min of no stimulation (Study I only). The results indicated that low-frequency bursts of TENS applied to the skin overlying the finger flexor muscles enhance the EMG activity of the finger flexors and grip force. The increase in EMG activity of the flexor muscles was observed after 20 min of stimulation, while grip force was increased only after 1 h. The effects of uni- and bilateral TENS were comparable. These observations allude to a modulatory effect of TENS on the tested motor responses; however, unequivocal conclusions of the findings are hampered by individual differences that affect motor outcomes, such as in level of attention.

  7. Comparison of hand grip strength and upper limb pressure pain threshold between older adults with or without non-specific shoulder pain

    PubMed Central

    2017-01-01

    Background There is a high prevalence of non-specific shoulder pain associated with upper limb functional limitations in older adults. The purpose of this study was to determine the minimal clinically important differences (MCID) of grip strength and pressure pain threshold (PPT) in the upper limb between older adults with or without non-specific shoulder pain. Methods A case-control study was carried out following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. A sample of 132 shoulders (mean ± SD years) with (n = 66; 76.04 ± 7.58) and without (n = 66; 75.05 ± 6.26) non-specific pain were recruited. The grip strength and PPT of the anterior deltoid and extensor carpi radialis brevis (ECRB) muscles were assessed. Results There were statistically significant differences (mean ± SD; P-value) for anterior deltoid PPT (2.51 ± 0.69 vs 3.68 ± 0.65, kg/cm2; P < .001), ECRB PPT (2.20 ± 0.60 vs 3.35 ± 0.38 kg/cm2; P < .001) and grip strength (20.78 ± 10.94 vs 24.63 ± 9.38 kg; P = .032) between shoulders with and without non-specific pain, respectively. Discussion The MCID of 1.17 kg/cm2, 1.15 kg/cm2 and 3.84 kg were proposed for anterior deltoid PPT, ECRB PPT and grip strength, respectively, to assess the upper limb of older adults with non-specific shoulder pain after treatment. In addition, univariate and multivariate (linear regression and regression trees) analyses may be used to consider age distribution, sex, pain intensity, grip strength and PPT in older adults including clinical and epidemiological studies with non-specific shoulder pain. PMID:28289561

  8. Diurnal, seasonal, and sex patterns of heart rate in grip-restrained African giant rats (Cricetomys gambianus, Waterhouse).

    PubMed

    Dzenda, Tavershima; Ayo, Joseph O; Sinkalu, Victor O; Yaqub, Lukuman S

    2015-10-01

    This study was carried out to determine heart rate (HR) values, including diurnal, seasonal, and sex patterns, in the African giant rat (Cricetomys gambianus, Waterhouse). HR was measured using stethoscope in grip-restrained African giant rats of either sex (103 bucks and 98 does), live-trapped from a tropical Savannah, and caged individually in the laboratory during the harmattan (cold-dry), hot-dry, and rainy seasons over a 3-year period. The HR fluctuated between 90 and 210 beats per minute (bpm) throughout the study period. Diurnal changes in HR (mean ± SEM) during the hot-dry and rainy seasons were nonsignificant (P > 0.05), but the morning and afternoon values differed (P < 0.01) during the cold-dry season. The HR varied (P < 0.05) among seasons, with peak, nadir, and moderate values recorded during the cold-dry (165.8 ± 0.51 bpm), hot-dry (153.1 ± 0.74 bpm), and rainy (163.4 ± 0.70 bpm) seasons, respectively. Mean HR of bucks was lower than that of does during the cold-dry (P < 0.0001) and hot-dry (P < 0.01) seasons, but sex difference during the rainy season was insignificant (P > 0.05). Overall, mean HR was lower (P < 0.0001) in bucks (158.8 ± 0.53 bpm) than in does (164.8 ± 0.53 bpm). In conclusion, values of HR in African giant rats are shown for the first time. Season, sex, and daytime influenced the HR, and should be considered during clinical evaluations of the rats.

  9. Setting a chronology for the basal ice at Dye-3 and GRIP: Implications for the long-term stability of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Yau, Audrey M.; Bender, Michael L.; Blunier, Thomas; Jouzel, Jean

    2016-10-01

    The long-term stability of the Greenland Ice Sheet (GIS) is an important issue in our understanding of the climate system. Limited data suggest that the northern and southern sections extend well back into the Pleistocene, but most age constraints do not definitively date the ice. Here, we re-examine the GRIP and Dye-3 ice cores to provide direct ice core observations as to whether the GIS survived previous interglacials known to be warmer (˜130 ka) or longer (˜430 ka) than the present interglacial. We present geochemical analyses of the basal ice from Dye-3 (1991-2035 m) and GRIP (3020-3026 m) that characterize and date the ice. We analyzed the elemental and isotopic composition of O2, N2, and Ar, of trapped air in these two cores to assess the origin of trapped gases in silty ice. Dating of the trapped air was then achieved by measuring the paleoatmospheric δ40Ar/38Ar and the 17O anomaly (17Δ) of O2. The resulting age is a lower limit because the trapped air may be contaminated with crustal radiogenic 40Ar. The oldest average age of replicates measured at various depths is 970 ± 140 ka for the GRIP ice core and 400 ka ± 170 ka for Dye-3. 17Δ data from Dye-3 also argue strongly that basal ice in this core predates the Eemian. This confirms that the Greenland Ice Sheet did not completely melt at Southern Greenland during the last interglacial, nor did it completely melt at Summit Greenland during the unusually long interglacial ˜430 kyr before present.

  10. Radiation accident grips Goiania

    SciTech Connect

    Roberts, L.

    1987-11-20

    On 13 September two young scavengers in Goiania, Brazil, removed a stainless steel cylinder from a cancer therapy machine in an abandoned clinic, touching off a radiation accident second only to Chernobyl in its severity. On 18 September they sold the cylinder, the size of a 1-gallon paint can, to a scrap dealer for $25. At the junk yard an employee dismantled the cylinder and pried open the platinum capsule inside to reveal a glowing blue salt-like substance - 1400 curies of cesium-137. Fascinated by the luminescent powder, several people took it home with them. Some children reportedly rubbed in on their bodies like carnival glitter - an eerie image of how wrong things can go when vigilance over radioactive materials lapses. In all, 244 people in Goiania, a city of 1 million in central Brazil, were contaminated. The eventual toll, in terms of cancer or genetic defects, cannot yet be estimated. Parts of the city are cordoned off as radiation teams continue washing down buildings and scooping up radioactive soil. The government is also grappling with the political fallout from the accident.

  11. Short Term Microgravity Effect on Isometric Hand Grip and Precision Pinch Force with Visual and Propioceptive Feedback

    NASA Astrophysics Data System (ADS)

    Pastacaldi, P.; Bracciaferri, F.; Neri, G.; Porciani, M.; Zolesi, V.

    Experiments executed on the upper limb are assuming increasing significance in the frame of the Human Physiology in space, for at least two reasons: -the upper limb is the principal means of locomotion for the subject living in aspace station -fatigue can have a significant effect the hand, for the ordinary work on board,and in particular for the extra-vehicular activities. The degradation of the performances affecting the muscular-skeletal apparatus can be easily recognized on the upper limb, by exerting specific scientific protocols, to be repeated through the permanence of the subject in weightlessness conditions. Also, the effectiveness of adequate counter-measures aimed to the reduction of calcium and muscular mass need to be verified, by means of specific assessments on the upper limb. Another aspect relevant to the effect of microgravity on the upper limb is associated with the alteration of the motor control programs due to the different gravity factor, affecting not only the bio-mechanics of the subject, but in general all his/her psycho- physical conditions, induced by the totally different environment. Specific protocols on the upper limb can facilitate the studies on learning mechanisms for the motor control. The results of such experiments can be transferred to the Earth, useful for treatment of subjects with local traumas or diseases of the Central Nervous System.In the frame of the mission of the Italian astronaut Roberto Vittori on board the International Space Station (ISS), the Italian Space Agency (ASI) has promoted the program "Marco Polo", with a number of experiments devoted to the study of the effect of microgravity on the human body. The experiment CHIRO ("Crew's Health: Investigation on Reduced Operability) is a part of the program. Its purpose is the determination of the influence of the altered gravity on the control of the grip force exerted by the hand or by a group of fingers and the adaptive behavior of this control through the

  12. Transverse carpal ligament: its effect on flexor tendon excursion, morphologic changes of the carpal canal, and on pinch and grip strengths after open carpal tunnel release.

    PubMed

    Netscher, D; Mosharrafa, A; Lee, M; Polsen, C; Choi, H; Steadman, A K; Thornby, J

    1997-09-01

    A three-part study is described that examines postoperative weakness after open carpal tunnel release and investigates the role of the transverse carpal ligament in the digital flexor pulley system. The effect of this ligament on flexor tendon excursion is evaluated in a cadaver study. Magnetic resonance imaging analysis is used to determine whether division of the transverse carpal ligament promotes volar migration of the median nerve and flexor tendons. Finally, the effects of ligament division and various methods of transverse carpal ligament reconstruction on the return of grip and pinch strengths after open carpal tunnel release are evaluated. The authors were able to determine that transverse carpal ligament reconstruction, particularly the transposition flap repair technique, after open carpal tunnel release confers a mechanical advantage and that the transverse carpal ligament is an important pulley for flexor tendon excursion. Based on the magnetic resonance imaging studies, volar displacement of carpal contents is reduced in patients undergoing transverse carpal ligament reconstruction by means of a transposition flap compared with those undergoing no ligament reconstruction and those undergoing reconstruction using the palmar aponeurosis. Postoperative grip and pinch strength values for the transposition flap repair group surpassed those of the other two groups at 12 weeks.

  13. A comparison of hand grasp breakaway strengths and bare-handed grip strengths of the astronauts, SML 3 test subjects, and the subjects from the general population

    NASA Technical Reports Server (NTRS)

    Rajulu, Sudhakar L.; Klute, Glenn K.

    1993-01-01

    Astronauts have the task of retrieving and deploying satellites and handling massive objects in a around the payload bay. Concerns were raised that manual handling of such massive objects might induce loads to the shuttle suits exceeding the design-certified loads. The Crew and Thermal Division of NASA JSC simulated the satellite handling tasks (Satellite Manload Tests 1 and 3) and determined the maximum possible load that a suited member could impart onto the suit. In addition, the tests revealed that the load to the suit by an astronaut could be calculated from the astronaut's maximum hand grasp breakaway strength. Thus, this study was conducted to document that hand grasp breakaway strengths of the astronauts who were scheduled to perform EVA during the upcoming missions. In addition, this study verified whether the SML 3 test results were sufficient for documenting the maximum possible load. An attempt was made to predict grasp strength from grip strength and hand anthropometry. Based on the results from this study, the SML 3 test results were deemed sufficient to document the maximum possible load on the suit. Finally, prediction of grasp strength from grip strength was not as accurate as expected. Hence, it was recommended that grasp strength be collected from the astronauts in order to obtain accurate load estimation.

  14. Understanding end-of-life caring practices in the emergency department: developing Merleau-Ponty's notions of intentional arc and maximum grip through praxis and phronesis.

    PubMed

    Chan, Garrett K

    2005-01-01

    The emergency department (ED) is a fast-paced, highly stressful environment where clinicians function with little or suboptimal information and where time is measured in minutes and hours. In addition, death and dying are phenomena that are often experienced in the ED. Current end-of-life care models, based on chronic illness trajectories, may be difficult to apply in the ED. A philosophical approach examining end-of-life care may help us understand how core medical and nursing values are embodied as care practices and as ethical comportment. The integration of Aristotle's notions of phronesis and praxis with Merleau-Ponty's ontological notions of intentional arc and maximum grip in the context of the culture and practices of the ED offers a unique view of clinical and ethical practice at the end-of-life in the emergency setting. Caring for people at the end-of-life calls us to act virtuously based on previous experience, meanings and local practices. The maximum grip of the ultimate particulars of the situation combined with one's experiential and theoretical knowledge opens up situated possibilities for the expert clinician.

  15. The effects of upper limb posture and a sub-maximal gripping task on corticospinal excitability to muscles of the forearm.

    PubMed

    Forman, Davis A; Baarbé, Julianne; Daligadu, Julian; Murphy, Bernadette; Holmes, Michael W R

    2016-04-01

    Variations in handgrip force influences shoulder muscle activity, and this effect is dependent upon upper limb position. Previous work suggests that neural coupling between proximal and distal muscles with changes in joint position is a possible mechanism but these studies tend to use artificially constrained postures that do not reflect activities of daily living. The purpose of this study was to examine the effects of upper limb posture on corticospinal excitability to the forearm muscles during workplace relevant arm positions. Motor evoked potentials (MEPs) were elicited in four forearm muscles via transcranial magnetic stimulation at six arm positions (45°, 90° and 120° of humeral elevation in both the flexion and abduction planes). MEPs were delivered as stimulus-response curves (SRCs) at rest and at constant intensity during two gripping tasks. Boltzmann plateau levels were smaller for the flexor carpi radialis in flexion at 45° versus 90° (p=0.0008). Extensor carpi radialis had a greater plateau during flexion than abduction (p=0.0042). Corticospinal excitability to the forearm muscles were influenced by upper limb posture during both the resting and gripping conditions. This provides further evidence that upper limb movements are controlled as a whole rather than segmentally and is relevant for workplace design considerations.

  16. Handedness for Unimanual Grasping in 564 Great Apes: The Effect on Grip Morphology and a Comparison with Hand Use for a Bimanual Coordinated Task

    PubMed Central

    Meguerditchian, Adrien; Phillips, Kimberley A.; Chapelain, Amandine; Mahovetz, Lindsay M.; Milne, Scott; Stoinski, Tara; Bania, Amanda; Lonsdorf, Elizabeth; Schaeffer, Jennifer; Russell, Jamie; Hopkins, William D.

    2015-01-01

    A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left hand in all four species. There was no significant sex effect on the patterns of handedness. In a subsample of apes, we also compared consistency in hand use for simple reaching with previously published data on a task that measures handedness for bimanual actions. We found that the ratio of subjects with consistent right compared to left hand use was more prevalent in bonobos, chimpanzees and gorillas but not orangutans. However, for all species, the proportion of subjects with inconsistent hand preferences between the tasks was relatively high suggesting some measures may be more sensitive in assessing handedness than others. PMID:26635693

  17. Observations of C-Band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate from the Hurricane Imaging Radiometer (HIRAD) during GRIP and HS3

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Roberts, J. B.; Biswas, S.; Jones, W. L.; Johnson, J.; Farrar, S.; Ruf, C. S.; Uhlhorn, E. W.; Atlas, R.; Black, Peter G.

    2013-01-01

    HIRAD is a new technology developed by NASA/MSFC, in partnership with NOAA and the Universities of Central Florida, Michigan, and Alabama-Huntsville. HIRAD is designed to measure wind speed and rain rate over a wide swath in heavy-rain, strong-wind conditions. HIRAD is expected to eventually fly routinely on unmanned aerial vehicles (UAVs) such as Global Hawk over hurricanes threatening the U.S. coast and other Atlantic basin areas, and possibly in the Western Pacific as well. HIRAD first flew on GRIP in 2010 and is part of the 2012-14 NASA Hurricane and Severe Storm Sentinel (HS3) mission on the Global Hawk, a high-altitude UAV. The next-generation HIRAD will include wind direction observations, and the technology can eventually be used on a satellite platform to extend the dynamical range of Ocean Surface Wind (OSV) observations from space.

  18. Reattachment of the greater trochanter in total hip arthroplasty: the pin-sleeve system compared with the Dall-Miles cable grip system

    PubMed Central

    Itoman, Moritoshi; Uchiyama, Katsufumi; Takasaki, Sumitaka; Fukushima, Kensuke

    2010-01-01

    The purpose of this study was to compare two different types of fixation systems used to reattach the greater trochanter after revision or total hip arthroplasty. This is a retrospective review of the results of patients that were treated with the two systems. We reviewed the clinical and radiological records of 35 hips with the Dall-Miles cable grip system (DMCGS) and 42 hips with the pin-sleeve system (PSS); follow-up averaged 24 months (range, 4–54) and 30 months (range, 11–42), respectively. The incidences of unsatisfactory clinical and radiological results in the PSS group was less than half that in the DMCGS group. Significant differences were found between the groups with respect to discomfort, tenderness, pain on motion, cable fragmentation, and bone absorption. Compared with the DMCGS, these results suggest the PSS could be the instrument of choice for re-attachment of the greater trochanter in hip arthroplasty. PMID:20238113

  19. Observations of C-Band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate from the Hurricane Imaging Radiometer (HIRAD) during GRIP and HS3

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Roberts, J. B.; Jones, W. L.; Biswas, S.; Ruf, C. S.; Uhlhorn, E. W.; Atlas, R.; Black, P.; Albers, C.

    2013-01-01

    HIRAD flew on high-altitude aircraft over Earl and Karl during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010, and at the time of this writing plans to fly over Atlantic tropical cyclones in September of 2012 as part of the Hurricane and Severe Storm Sentinel (HS3) mission. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be retrieved. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years to obtain observations within a single footprint at nadir angle. Results from the flights during the GRIP and HS3 campaigns will be shown, including images of brightness temperatures, wind speed, and rain rate. Comparisons will be made with observations from other instruments on the campaigns, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eye-wall, location of storm wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

  20. Hurricane Imaging Radiometer (HIRAD) Observations of Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate During NASA's GRIP and HS3 Campaigns

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Roberts, J. B.; Jones, W. L.; Biswas, S.; Ruf, C. S.; Uhlhorn, E. W.; Atlas, R.; Black, P.; Albers, C.

    2012-01-01

    HIRAD flew on high-altitude aircraft over Earl and Karl during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010, and plans to fly over Atlantic tropical cyclones in September of 2012 as part of the Hurricane and Severe Storm Sentinel (HS3) mission. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain spatial resolution of approximately 2 km, out to roughly 30 km each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be retrieved. The physical retrieval technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years to obtain observations within a single footprint at nadir angle. Results from the flights during the GRIP and HS3 campaigns will be shown, including images of brightness temperatures, wind speed, and rain rate. Comparisons will be made with observations from other instruments on the campaigns, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eye-wall, location of storm wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

  1. Vitamin D Receptor Ablation and Vitamin D Deficiency Result in Reduced Grip Strength, Altered Muscle Fibers, and Increased Myostatin in Mice.

    PubMed

    Girgis, Christian M; Cha, Kuan Minn; Houweling, Peter J; Rao, Renuka; Mokbel, Nancy; Lin, Mike; Clifton-Bligh, Roderick J; Gunton, Jenny E

    2015-12-01

    Vitamin D deficiency is associated with muscle weakness, pain, and atrophy. Serum vitamin D predicts muscle strength and age-related muscle changes. However, precise mechanisms by which vitamin D affects skeletal muscle are unclear. To address this question, this study characterizes the muscle phenotype and gene expression of mice with deletion of vitamin D receptor (VDRKO) or diet-induced vitamin D deficiency. VDRKO and vitamin D-deficient mice had significantly weaker grip strength than their controls. Weakness progressed with age and duration of vitamin D deficiency, respectively. Histological assessment showed that VDRKO mice had muscle fibers that were significantly smaller in size and displayed hyper-nuclearity. Real-time PCR also indicated muscle developmental changes in VDRKO mice with dysregulation of myogenic regulatory factors (MRFs) and increased myostatin in quadriceps muscle (>2-fold). Vitamin D-deficient mice also showed increases in myostatin and the atrophy marker E3-ubiqutin ligase MuRF1. As a potential explanation for grip strength weakness, both groups of mice had down-regulation of genes encoding calcium-handling and sarco-endoplasmic reticulum calcium transport ATPase (Serca) channels. This is the first report of reduced strength, morphological, and gene expression changes in VDRKO and vitamin D-deficient mice where confounding by calcium, magnesium, and phosphate have been excluded by direct testing. Although suggested in earlier in vitro work, this study is the first to report an in vivo association between vitamin D, myostatin, and the regulation of muscle mass. These findings support a direct role for vitamin D in muscle function and corroborate earlier work on the presence of VDR in this tissue.

  2. The relationship of birthweight, muscle size at birth and post-natal growth to grip strength in 9-year-old Indian children: findings from the Mysore Parthenon study.

    PubMed

    Barr, J G; Veena, S R; Kiran, K N; Wills, A K; Winder, N R; Kehoe, S; Fall, C H D; Sayer, A A; Krishnaveni, G V

    2010-10-01

    Foetal development may permanently affect muscle function. Indian newborns have a low mean birthweight, predominantly due to low lean tissue and muscle mass. We aimed to examine the relationship of birthweight, and arm muscle area (AMA) at birth and post-natal growth to handgrip strength in Indian children. Grip strength was measured in 574 children aged 9 years, who had detailed anthropometry at birth and every 6-12 months post-natally. Mean (standard deviation (s.d.)) birthweight was 2863 (446) g. At 9 years, the children were short (mean height s.d. -0.6) and light (mean weight s.d. -1.1) compared with the World Health Organization growth reference. Mean (s.d.) grip strength was 12.7 (2.2) kg (boys) and 11.0 (2.0) kg (girls). Weight, length and AMA at birth, but not skinfold measurements at birth, were positively related to 9-year grip strength (β = 0.40 kg/s.d. increase in birthweight, P < 0.001; and β = 0.41 kg/s.d. increase in AMA, P < 0.001). Grip strength was positively related to 9-year height, body mass index and AMA and to gains in these measurements from birth to 2 years, 2-5 years and 5-9 years (P < 0.001 for all). The associations between birth size and grip strength were attenuated but remained statistically significant for AMA after adjusting for 9-year size. We conclude that larger overall size and muscle mass at birth are associated with greater muscle strength in childhood, and that this is mediated mainly through greater post-natal size. Poorer muscle development in utero is associated with reduced childhood muscle strength.

  3. Retraining and assessing hand movement after stroke using the MusicGlove: comparison with conventional hand therapy and isometric grip training

    PubMed Central

    2014-01-01

    Background It is thought that therapy should be functional, be highly repetitive, and promote afferent input to best stimulate hand motor recovery after stroke, yet patients struggle to access such therapy. We developed the MusicGlove, an instrumented glove that requires the user to practice gripping-like movements and thumb-finger opposition to play a highly engaging, music-based, video game. The purpose of this study was to 1) compare the effect of training with MusicGlove to conventional hand therapy 2) determine if MusicGlove training was more effective than a matched form of isometric hand movement training; and 3) determine if MusicGlove game scores predict clinical outcomes. Methods 12 chronic stroke survivors with moderate hemiparesis were randomly assigned to receive MusicGlove, isometric, and conventional hand therapy in a within-subjects design. Each subject participated in six one-hour treatment sessions three times per week for two weeks, for each training type, for a total of 18 treatment sessions. A blinded rater assessed hand impairment before and after each training type and at one-month follow-up including the Box and Blocks (B & B) test as the primary outcome measure. Subjects also completed the Intrinsic Motivation Inventory (IMI). Results Subjects improved hand function related to grasping small objects more after MusicGlove compared to conventional training, as measured by the B & B score (improvement of 3.21±3.82 vs. -0.29±2.27 blocks; P=0.010) and the 9 Hole Peg test (improvement of 2.14±2.98 vs. -0.85±1.29 pegs/minute; P=0.005). There was no significant difference between training types in the broader assessment batteries of hand function. Subjects benefited less from isometric therapy than MusicGlove training, but the difference was not significant (P>0.09). Subjects sustained improvements in hand function at a one month follow-up, and found the MusicGlove more motivating than the other two therapies, as measured by the IMI. Music

  4. Slip of grip of a molecular motor on a crowded track: Modeling shift of reading frame of ribosome on RNA template

    NASA Astrophysics Data System (ADS)

    Mishra, Bhavya; Schütz, Gunter M.; Chowdhury, Debashish

    2016-06-01

    We develop a stochastic model for the programmed frameshift of ribosomes synthesizing a protein while moving along a mRNA template. Normally the reading frame of a ribosome decodes successive triplets of nucleotides on the mRNA in a step-by-step manner. We focus on the programmed shift of the ribosomal reading frame, forward or backward, by only one nucleotide which results in a fusion protein; it occurs when a ribosome temporarily loses its grip to its mRNA track. Special “slippery” sequences of nucleotides and also downstream secondary structures of the mRNA strand are believed to play key roles in programmed frameshift. Here we explore the role of an hitherto neglected parameter in regulating -1 programmed frameshift. Specifically, we demonstrate that the frameshift frequency can be strongly regulated also by the density of the ribosomes, all of which are engaged in simultaneous translation of the same mRNA, at and around the slippery sequence. Monte Carlo simulations support the analytical predictions obtained from a mean-field analysis of the stochastic dynamics.

  5. Dynamics and Predictability of Tropical Cyclone Genesis Evaluated through a Coupled EnKF and 4DVar Data Assimilation Method during GRIP and PREDICT 2010.

    NASA Astrophysics Data System (ADS)

    Reyes, A.; Jenkins, G. S.; Poterjoy, J.; Zhang, F.

    2014-12-01

    The genesis of Hurricane Karl (2010) and Tropical Storm Mathew (2010) are examined and compared using a coupled ensemble Kalman filter and four-dimension variational data assimilation method (E4DVar) to assimilate conventional and field campaign observations. This research makes use of dropsonde and sounding observations, which were collected during both the Genesis and Rapid Intensification Processes (GRIP) and the Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT) field campaigns. E4DVar uses a mix of climatological and flow-dependent background error covariance obtained from ensemble forecasts together with the tangent linear model and its adjoint to perform the four-dimensional data assimilation. As a result, E4DVar analyses are able to capture multi-scale features of the developing disturbances accurately, such as the evolving thermodynamic and kinematic structure of pre-genesis Karl and Mathew. Preliminary diagnostics shows that the genesis of both storms followed a bottom-up process with several mesoscale convective vorticies (MCVs) observed in the pre-genesis stages. To determine the role of these MCVs and to better understand the initial development of the surface cyclone, a two-dimensional spectral decomposition and filtering of model variables, together with a vorticity budget, are performed on high-resolution (1.5 km) simulations of both systems.

  6. Studyng the Influence of Aerosols in the Evolution of Cloud Microphysics Procesess Associated with Tropical Cyclone Earl Using Airborne Measurements from the NASA Grip Field Campaing 2010

    NASA Astrophysics Data System (ADS)

    Luna-Cruz, Y.; Heymsfield, A.; Jenkins, G. S.; Bansemer, A.

    2011-12-01

    Cloud microphysics processes are strongly related to tropical cyclones evolution. Although there have been three decades of research dedicated to understand the role of cloud microphysics in tropical cyclogenesis, there are still questions unanswered. With the intention of fulfill the gaps and to better understand the processes involves in tropical storms formation the NASA Genesis and Rapid Intensification Processes (GRIP) field campaign was conducted during the months of August and September of 2010. In-situ microphysical measurements, including particle size distributions, shapes, liquid/ice water content and supercooled liquid water were obtained from the DC-8 aircraft. A total of 139 hrs of flying science modules were performed including sampling of four named storms (Earl, Gaston, Karl and Matthew). One tropical cyclone, Earl, was one of the major hurricanes of the season reaching a category 4 in the Saffir-Simpson scale. Earl emerged from the West Africa on August 22 as an easterly wave, moved westward and became a tropical storm on August 25 before undergoing rapid intensification. This project seeks to explore the lifecycle of hurricane Earl including the genesis and rapid intensification from a microphysics perspective; to develop a better understanding of the relationship between dust from the Saharan Air Layer and cloud microphysics evolution and to develop a better understanding of how cloud microphysics processes interacts and serve as precursor for thermodynamics processes. An overview of the microphysics measurements as well as preliminary results will be presented.

  7. Nut-cracking behaviour in wild-born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand-preference, hand grips and efficiency.

    PubMed

    Neufuss, Johanna; Humle, Tatyana; Cremaschi, Andrea; Kivell, Tracy L

    2017-02-01

    There has been an enduring interest in primate tool-use and manipulative abilities, most often with the goal of providing insight into the evolution of human manual dexterity, right-hand preference, and what behaviours make humans unique. Chimpanzees (Pan troglodytes) are arguably the most well-studied tool-users amongst non-human primates, and are particularly well-known for their complex nut-cracking behaviour, which has been documented in several West African populations. However, their sister-taxon, the bonobos (Pan paniscus), rarely engage in even simple tool-use and are not known to nut-crack in the wild. Only a few studies have reported tool-use in captive bonobos, including their ability to crack nuts, but details of this complex tool-use behaviour have not been documented before. Here, we fill this gap with the first comprehensive analysis of bonobo nut-cracking in a natural environment at the Lola ya Bonobo sanctuary, Democratic Republic of the Congo. Eighteen bonobos were studied as they cracked oil palm nuts using stone hammers. Individual bonobos showed exclusive laterality for using the hammerstone and there was a significant group-level right-hand bias. The study revealed 15 hand grips for holding differently sized and weighted hammerstones, 10 of which had not been previously described in the literature. Our findings also demonstrated that bonobos select the most effective hammerstones when nut-cracking. Bonobos are efficient nut-crackers and not that different from the renowned nut-cracking chimpanzees of Bossou, Guinea, which also crack oil palm nuts using stones.

  8. Hand grip strength is associated with forced expiratory volume in 1 second among subjects with COPD: report from a population-based cohort study

    PubMed Central

    Strandkvist, Viktor Johansson; Backman, Helena; Röding, Jenny; Stridsman, Caroline; Lindberg, Anne

    2016-01-01

    Background Cardiovascular diseases and skeletal muscle dysfunction are common comorbidities in COPD. Hand grip strength (HGS) is related to general muscle strength and is associated with cardiovascular disease and all-cause mortality, while the results from small selected COPD populations are contradictory. The aim of this population-based study was to compare HGS among the subjects with and without COPD, to evaluate HGS in relation to COPD severity, and to evaluate the impact of heart disease. Subjects and methods Data were collected from the Obstructive Lung disease in Northern Sweden COPD study, where the subjects with and without COPD have been invited to annual examinations since 2005. In 2009–2010, 441 subjects with COPD (postbronchodilator forced expiratory volume in 1 second [FEV1]/vital capacity <0.70) and 570 without COPD participated in structured interviews, spirometry, and measurements of HGS. Results The mean HGS was similar when comparing subjects with and without COPD, but those with heart disease had lower HGS than those without. When compared by Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, the subjects with GOLD 3–4 had lower HGS than those without COPD in both sexes (females 21.4 kg vs 26.9 kg, P=0.010; males 41.5 kg vs 46.3 kg, P=0.038), and the difference persisted also when adjusted for confounders. Among the subjects with COPD, HGS was associated with FEV1% of predicted value but not heart disease when adjusted for height, age, sex, and smoking habits, and the pattern was similar among males and females. Conclusion In this population-based study, the subjects with GOLD 3–4 had lower HGS than the subjects without COPD. Among those with COPD, HGS was associated with FEV1% of predicted value but not heart disease, and the pattern was similar in both sexes. PMID:27785009

  9. Functional connectivity associated with hand shape generation: Imitating novel hand postures and pantomiming tool grips challenge different nodes of a shared neural network.

    PubMed

    Vingerhoets, Guy; Clauwaert, Amanda

    2015-09-01

    Clinical research suggests that imitating meaningless hand postures and pantomiming tool-related hand shapes rely on different neuroanatomical substrates. We investigated the BOLD responses to different tasks of hand posture generation in 14 right handed volunteers. Conjunction and contrast analyses were applied to select regions that were either common or sensitive to imitation and/or pantomime tasks. The selection included bilateral areas of medial and lateral extrastriate cortex, superior and inferior regions of the lateral and medial parietal lobe, primary motor and somatosensory cortex, and left dorsolateral prefrontal, and ventral and dorsal premotor cortices. Functional connectivity analysis revealed that during hand shape generation the BOLD-response of every region correlated significantly with every other area regardless of the hand posture task performed, although some regions were more involved in some hand postures tasks than others. Based on between-task differences in functional connectivity we predict that imitation of novel hand postures would suffer most from left superior parietal disruption and that pantomiming hand postures for tools would be impaired following left frontal damage, whereas both tasks would be sensitive to inferior parietal dysfunction. We also unveiled that posterior temporal cortex is committed to pantomiming tool grips, but that the involvement of this region to the execution of hand postures in general appears limited. We conclude that the generation of hand postures is subserved by a highly interconnected task-general neural network. Depending on task requirements some nodes/connections will be more engaged than others and these task-sensitive findings are in general agreement with recent lesion studies.

  10. Clip-on extensometer grip

    DOEpatents

    Korellis, J.S.

    1986-08-12

    A self-gauging extensometer assembly for measuring axial strain of a test specimen through the wall of a high temperature furnace comprises an extensometer having a pair of telescoping arms carrying jaws that clip to the specimen at points spaced apart from each other by a predetermined gauge length. The jaws, which open parallel to the longitudinal axis of the telescoping arms, are biased closed into contact with opposite sides of the specimen by helical springs. A knife edge formed in each jaw prevents any slippage of the specimen between jaws during measurements. Because the jaws of the telescoping arms require no lateral pivoting, to open or close, the assembly is able to be clipped to a specimen through a relatively small opening in the furnace wall.

  11. Finding Relief from Allergy's Grip

    MedlinePlus

    ... on. Antihistamines. These medications counter the effects of histamine, the substance that makes eyes water and noses ... stop hay fever, perhaps by blocking release of histamine and other symptomproducing chemicals. This product has few ...

  12. In the grips of growth.

    PubMed

    Sherman, D

    1992-04-01

    Rapid population growth and increasing environmental degradation threaten the likelihood of a better life for citizens in the US and those in developing countries in the future. To achieve sustainable development, population cannot continue to grow (possible 3-fold increase during the 20th century) since it only burdens the earth and future generations with more and more pollution, waste, and resource depletion. Warning signs already exist: global warming, ozone depletion, vanishing species, and deforestations. Future projections for population growth highlight the problem of employment, unemployment, and underemployment, and underemployment in the US and even more so in developing countries where they are already of great concern. The US population is growing faster than any other developed nation. Yet many economists believe that population growth equated a healthy economy and environmental degradation is necessary for progress. The Workforce 2000 report prepared by conservative think tank contends that even though unemployment increases steadily, the US will soon face a shortage of workers. The report used misleading data and false assumptions, however. For example, it shows the work force growing at 1%/year in the 1990s compared with 3% in the 1970s, but the higher growth in the 1970s was due to the maturing of the baby boomers. Other economists note that in a stable population, fewer people compete for jobs which increases wages and thus the standard of living for most people. Communities can monitor local food, water, and energy supplies, jobs, and health care in a stable population. Company worries about labor shortages are really worries about shortages of cheap labor, consequently many companies are moving factories outside the US where they can employ cheap labor. An economist who favors self-reliance notes that the US population policy is to let population take its natural course, which is antiquated thinking.

  13. Getting a Grip on Complexes

    PubMed Central

    Nie, Yan; Viola, Cristina; Bieniossek, Christoph; Trowitzsch, Simon; Vijay-achandran, Lakshmi Sumitra; Chaillet, Maxime; Garzoni, Frederic; Berger, Imre

    2009-01-01

    We are witnessing tremendous advances in our understanding of the organization of life. Complete genomes are being deciphered with ever increasing speed and accuracy, thereby setting the stage for addressing the entire gene product repertoire of cells, towards understanding whole biological systems. Advances in bioinformatics and mass spectrometric techniques have revealed the multitude of interactions present in the proteome. Multiprotein complexes are emerging as a paramount cornerstone of biological activity, as many proteins appear to participate, stably or transiently, in large multisubunit assemblies. Analysis of the architecture of these assemblies and their manifold interactions is imperative for understanding their function at the molecular level. Structural genomics efforts have fostered the development of many technologies towards achieving the throughput required for studying system-wide single proteins and small interaction motifs at high resolution. The present shift in focus towards large multiprotein complexes, in particular in eukaryotes, now calls for a likewise concerted effort to develop and provide new technologies that are urgently required to produce in quality and quantity the plethora of multiprotein assemblies that form the complexome, and to routinely study their structure and function at the molecular level. Current efforts towards this objective are summarized and reviewed in this contribution. PMID:20514218

  14. Independent digit movements and precision grip patterns in 1-5-month-old human infants: hand-babbling, including vacuous then self-directed hand and digit movements, precedes targeted reaching.

    PubMed

    Wallace, Patricia S; Whishaw, Ian Q

    2003-01-01

    Previous work has described human reflexive grasp patterns in early infancy and visually guided reaching and grasping in late infancy. There has been no examination of hand movements in the intervening period. This was the purpose of the present study. We video recorded the spontaneous hand and digit movements made by alert infants over their first 5 months of age. Over this period, spontaneous hand and digit movements developed from fists to almost continuous, vacuous movements and then to self-directed grasping movements. Amongst the many hand and digit movements observed, four grasping patterns emerged during this period: fists, pre-precision grips associated with numerous digit postures, precision grips including the pincer grasp, and self-directed grasps. The finding that a wide range of independent digit movements and grasp patterns are displayed spontaneously by infants within their first 5 months of age is discussed in relation to the development of the motor system, including the suggestion that direct connections of the pyramidal tract are functional relatively early in infancy. It is also suggested that hand babbling, consisting of first vacuous and then self-directed movements, is preparatory to targeted reaching.

  15. The speed and timing of climate change: Detailed ice core stable isotope records from NorthGRIP, Greenland and Mt. Moulton, West Antarctica

    NASA Astrophysics Data System (ADS)

    Popp, Trevor J.

    Objective projections of future climate change require a detailed understanding of the natural variability and behavior of the climate system observed in the past. This dissertation endeavors to characterize the speed and timing of past climate changes on both orbital and extremely abrupt time scales from new high-resolution stable isotope time series from ice cores collected at NorthGRIP in Greenland and Mt. Moulton in West Antarctica. Greenland ice cores are uniquely suited for study of abrupt climate events because relatively high snow accumulation rates allow single years to be identified well into the last glacial period. Deuterium (deltaD) and deuterium excess time series at near annual resolution or better across the three major abrupt transitions of the last glacial termination are examined from the precisely dated NGRIP ice core. These records have been synchronized to within a few years or less to similar isotopic series developed from the GISP2 ice core which was collected 320 km SSE of the NGRIP site. 300-500 year time intervals were examined in detail at the end of the Younger Dryas (YD, 11.7 ka), the beginning of the YD (12.9 ka), and at the onset of Bolling (14.7 ka). Transition timing, duration and amplitudes were determined for each transition at both sites via a statistical ramp fitting approach. At each transition a complete mode shift between two climate states recorded by deltaD or excess, or both, was detected in as little as a single year with one exception at the cooling at the onset of the YD at GISP2. NGRIP and GISP2 share much common variance, sometimes in remarkable detail, in the timing and evolution of the climate transitions. Complete mode shifts in excess were synchronous to within a year or better between NGRIP and GISP2 for the two cold-to-warm transitions and represent a significant regional reorganization of atmospheric circulation delivering moisture from lower latitude source regions to the high latitudes of Greenland. At the

  16. Relationships between Greenland and lower latitude climate over the last glacial period from new high resolution measurements of 17O-excess and d-excess on the NorthGRIP ice core

    NASA Astrophysics Data System (ADS)

    Landais, Amaelle; Prie, Frederic; Minster, Benedicte; Masson-Delmotte, Valerie; Vinther, Bo; Popp, Trevor; Rhodes, Rachael; Dahl-Jensen, Dorther

    2016-04-01

    Greenland ice cores have long revealed the abrupt climatic variability characterizing the last glacial period (succession of Dansgaard-Oeschger events). Since then, many other continental and marine records have shown the northern hemispheric extent of these abrupt events with an associated signature in the southern hemisphere. While the water isotopic records (d18O or dD) records of Greenland ice cores have long been used as references for the northern hemisphere climatic variability, more and more pieces of evidence point to some decoupling between the climate variability in Greenland and the climate variability in lower latitudes. In particular, the Greenland temperature records derived from water and air isotopes do not exhibit any signature for the Heinrich events. We present here new high resolution measurements of 17O-excess and d-excess from the NorthGRIP ice core covering the abrupt climatic variability of the last deglaciation and the last glacial period. These second order parameters are particularly useful to decipher the local from the distant effect on the water isotopic records in polar ice cores since they are sensitive to climatic conditions at the oceanic evaporative regions and to the trajectories of the water mass toward the polar precipitation sites. These new measurements clearly highlight a decoupling between Greenland and lower latitudes between the cold phases (stadials) of the Dansgaard-Oeschger events that can be due to sea-ice extent or other modifications in the oceanic surface climatic conditions. A comparison between the d-excess records of the GRIP and NGRIP ice core highlight different behaviours in the trajectories of moisture toward different regions Greenland that can again be linked to regional differences in sea-ice extent. Finally, our new sets of data also exhibit a particular behavior of the Greenland vs lower latitude climate during very short Dansgaard-Oeschger events.

  17. Orientia tsutsugamushi Ank9 is a multifunctional effector that utilizes a novel GRIP-like Golgi localization domain for Golgi-to-endoplasmic reticulum trafficking and interacts with host COPB2.

    PubMed

    Beyer, Andrea R; Rodino, Kyle G; VieBrock, Lauren; Green, Ryan S; Tegels, Brittney K; Oliver, Lee D; Marconi, Richard T; Carlyon, Jason A

    2017-01-19

    Orientia tsutsugamushi causes scrub typhus, a potentially fatal infection that afflicts 1 million people annually. This obligate intracellular bacterium boasts one of the largest microbial arsenals of ankyrin repeat-containing protein (Ank) effectors, most of which target the endoplasmic reticulum (ER) by undefined mechanisms. Ank9 is the only one proven to function during infection. Here, we demonstrate that Ank9 bears a motif that mimics the GRIP domain of eukaryotic golgins and is necessary and sufficient for its Golgi localization. Ank9 reaches the ER exclusively by retrograde trafficking from the Golgi. Consistent with this observation, it binds COPB2, a host protein that mediates Golgi-to-ER transport. Ank9 destabilizes the Golgi and ER in a Golgi localization domain-dependent manner and induces the activating transcription factor 4-dependent unfolded protein response. The Golgi is also destabilized in cells infected with O. tsutsugamushi or treated with COPB2 small interfering RNA. COPB2 reduction and/or the cellular events that it invokes, such as Golgi destabilization, benefit Orientia replication. Thus, Ank9 or bacterial negative modulation of COPB2 might contribute to the bacterium's intracellular replication. This report identifies a novel microbial Golgi localization domain, links Ank9 to the ability of O. tsutsugamushi to perturb Golgi structure, and describes the first mechanism by which any Orientia effector targets the secretory pathway.

  18. Humans and robots: hand in grip.

    PubMed

    Hubbard, G Scott

    2005-01-01

    As we move boldly forward into the 21st century, there has rarely been a more exciting time in which to contemplate the future of space exploration. The President of the United States has made a new and ambitious commitment to exploration of the solar system and beyond. Robotic partners will play a vital role in ensuring that the Vision is truly "sustainable and affordable". Relevant science and technology will be discussed with particular emphasis on expertise from NASA Ames Research Center of which the author is Director. The likely evolution of the balance between human explorers and robotic explorers will be addressed.

  19. Hurricane Scientist talks GRIP, Hurricane Earl

    NASA Video Gallery

    Hurricane Earl, currently a powerful category 4 storm, is barreling north with the potential to batter the East Coast and threaten Labor Day plans for beachgoers from North Carolina to Massachusett...

  20. Vision-guided gripping of a cylinder

    NASA Technical Reports Server (NTRS)

    Nicewarner, Keith E.; Kelley, Robert B.

    1991-01-01

    The motivation for vision-guided servoing is taken from tasks in automated or telerobotic space assembly and construction. Vision-guided servoing requires the ability to perform rapid pose estimates and provide predictive feature tracking. Monocular information from a gripper-mounted camera is used to servo the gripper to grasp a cylinder. The procedure is divided into recognition and servo phases. The recognition stage verifies the presence of a cylinder in the camera field of view. Then an initial pose estimate is computed and uncluttered scan regions are selected. The servo phase processes only the selected scan regions of the image. Given the knowledge, from the recognition phase, that there is a cylinder in the image and knowing the radius of the cylinder, 4 of the 6 pose parameters can be estimated with minimal computation. The relative motion of the cylinder is obtained by using the current pose and prior pose estimates. The motion information is then used to generate a predictive feature-based trajectory for the path of the gripper.

  1. The Great Lakes Runoff Intercomparison Project (GRIP)

    NASA Astrophysics Data System (ADS)

    Gronewold, A. D.; Fortin, V.; Fry, L. M.

    2012-12-01

    As a continuation of investments in the development of alternative methods for estimating major components of the Great Lakes water budget through the recently-completed International Joint Commission (IJC) International Upper Great Lakes Study (IUGLS), representatives from a variety of United States and Canadian agencies have formed a bi-national collaboration to assess alternative methods for modeling runoff within the Great Lakes basin. The project is based on assessing and comparing simulated runoff across the watersheds of both Lake Michigan and Lake Ontario, with an emphasis on understanding the different sources of data needed to support these models, and a comparison between both total runoff and estimated runoff at individual gauging stations. Models, or modeling frameworks (and contributing agencies) participating in the project include (but are not limited to) Analysis of Flows in Networks of Channels (or AFINCH, from USGS), the Community Hydrologic Prediction System (or CHPS, from NOAA's National Weather Service), the MESH system (from Environment Canada), the Large Basin Runoff Model (or LBRM, from NOAA's Great Lakes Environmental Research Laboratory) as well as a series of empirical methods for extrapolating historical gauge measurements to ungauged portions of each Lake basin. This presentation will also explore alternative methods for comparing runoff estimates over broad spatial scales, and for understanding potential sources of bias and uncertainty within and between these estimates. For models generating probabilistic estimates (i.e. with an explicit expression of uncertainty) we provide a comparison based on posterior predictive p-values (similar to rank histograms), an approach which, unlike conventional deterministic metrics, provides an indication of the relative importance of uncertainty in large-scale hydrological model assessment and how expressions of that uncertainty propagate into model-based water resources management planning decisions.

  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. Getting a Grip on Grid Generation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    GridPro is an automatic, object-oriented, multi-block grid generator that provides ease of use, high quality, rapid production, and parametric design. When paired with a 3-D graphic user interface called az- Manager, GridPro presents users with an extremely efficient, interactive capability to build topology, edit surfaces, set computational fluid dynamics (CFD) boundary conditions, and view multi-block grids. The origins of the GridPro technology date back to a 1989 SBIR contract with NASA's Glenn Research Center, in which Glenn was seeking a multi-block grid generation program that would run automatically upon identifying a pattern of grid blocks supplied by a user. The technology is currently used in many engineering fields, including aerospace, turbo- machinery, automotive, and chemical industries.

  4. Getting a grip on Indian Ocean monsoons

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    An improved understanding of the Indian Ocean monsoon season could help researchers to better forecast floods and the associated spread of cholera in low-lying Bangladesh.In a joint effort by the University of Colorado at Boulder, the Asian Disaster Preparedness Center, and the Bangladesh government, researchers are using a variety of monitoring and forecast modeling tools to better understand and characterize the monsoon season's active and calm periods. By studying Indian Ocean climatic conditions and probabilities that lead to regular flooding of the Bangladesh delta, researchers also can provide probabilities concerning outbreaks of cholera, an intestinal disease that infects large segments of that country's population.

  5. Coming to Grips with Radical Social Constructivisms

    NASA Astrophysics Data System (ADS)

    Phillips, D. C.

    This essay distinguishes two broad groups - psychological constructivists and social constructivists - but focusses upon the second of these, although it is stressed that there is great within group variation. More than half of the paper is devoted to general clearing of the ground, during which the reasons for the growing acrimony in the debates between social constructivists and their opponents are assessed, an important consequence of these debates for education is discussed, and an examination is carried out of the radical social constructivist tendency to make strong and exciting but untenable claims which are then backed away from (a tendency which is documented by a close reading of the early pages in Bloors classic book). The last portion of the essay focuses upon social constructivist accounts of the causes of belief in science - the more radical of which denegrate the role of warranting reasons, and which give an exalted place to quasi-anthropological or sociological studies of scientific communities.

  6. NASA's GRIP Mission Flies Through Hurricane Earl

    NASA Video Gallery

    The eye of Hurricane Earl in the Atlantic Ocean is captured by a videographer aboard NASA’s DC-8 research aircraft on Monday, Aug. 30, 2010. The DC-8 passed through the eye of the storm six times j...

  7. Getting a Grip on Your Own Career.

    ERIC Educational Resources Information Center

    McKenna, Constance

    1982-01-01

    Examines the predictable stages in the career development of a vocational educator. Stage one covers adjustment to new situations; stage two focuses on acquiring continuing employment status; stage three (mid-career) often includes career crisis; stage four includes both security and lack of personal challenge; and stage five is retirement. (CT)

  8. Getting to Grips with Group Work

    ERIC Educational Resources Information Center

    Lane, Rebecca; Coker, Jessica; McNamara, Suzanne

    2005-01-01

    It is easy to take for granted that children often work together in groups unproblematically on practical science tasks. However, after a recent exercise in a small rural church school the authors realised that they had not considered fully the limitations they would encounter with group work. They had spent four one-hour sessions working with a…

  9. Getting a Grip on Librarian Evaluation

    ERIC Educational Resources Information Center

    Jaeger, Paige

    2013-01-01

    When the Common Core State Standards (CCSS) were adopted in many states, it was only one piece of the pie called Race to the Top (RttT). As states competed and clamored to win the Race to the Top dollars, they knew it came with strings attached. The biggest piece of string is called APPR, or Annual Professional Performance Review--and it is more…

  10. Internet-Based Implementation of Non-Pharmacological Interventions of the "People Getting a Grip on Arthritis" Educational Program: An International Online Knowledge Translation Randomized Controlled Trial Design Protocol

    PubMed Central

    Thomas, Roanne; De Angelis, Gino

    2015-01-01

    Background Rheumatoid arthritis (RA) affects 2.1% of the Australian population (1.5% males; 2.6% females), with the highest prevalence from ages 55 to over 75 years (4.4-6.1%). In Canada, RA affects approximately 0.9% of adults, and within 30 years that is expected to increase to 1.3%. With an aging population and a greater number of individuals with modifiable risk factors for chronic diseases, such as arthritis, there is an urgent need for co-care management of arthritic conditions. The increasing trend and present shifts in the health services and policy sectors suggest that digital information delivery is becoming more prominent. Therefore, it is necessary to further investigate the use of online resources for RA information delivery. Objective The objective is to examine the effect of implementing an online program provided to patients with RA, the People Getting a Grip on Arthritis for RA (PGrip-RA) program, using information communication technologies (ie, Facebook and emails) in combination with arthritis health care professional support and electronic educational pamphlets. We believe this can serve as a useful and economical method of knowledge translation (KT). Methods This KT randomized controlled trial will use a prospective randomized open-label blinded-endpoint design to compare four different intervention approaches of the PGrip-RA program to a control group receiving general electronic educational pamphlets self-management in RA via email. Depending on group allocation, links to the Arthritis Society PGrip-RA material will be provided either through Facebook or by email. One group will receive feedback online from trained health care professionals. The intervention period is 6 weeks. Participants will have access to the Internet-based material after the completion of the baseline questionnaires until the final follow-up questionnaire at 6 months. We will invite 396 patients from Canadian and Australian Arthritis Consumers’ Associations to

  11. The influence of visual feedback from the recent past on the programming of grip aperture is grasp-specific, shared between hands, and mediated by sensorimotor memory not task set.

    PubMed

    Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

    2015-05-01

    Goal-directed movements, such as reaching out to grasp an object, are necessarily constrained by the spatial properties of the target such as its size, shape, and position. For example, during a reach-to-grasp movement, the peak width of the aperture formed by the thumb and fingers in flight (peak grip aperture, PGA) is linearly related to the target's size. Suppressing vision throughout the movement (visual open loop) has a small though significant effect on this relationship. Visual open loop conditions also produce a large increase in the PGA compared to when vision is available throughout the movement (visual closed loop). Curiously, this differential effect of the availability of visual feedback is influenced by the presentation order: the difference in PGA between closed- and open-loop trials is smaller when these trials are intermixed (an effect we have called 'homogenization'). Thus, grasping movements are affected not only by the availability of visual feedback (closed loop or open loop) but also by what happened on the previous trial. It is not clear, however, whether this carry-over effect is mediated through motor (or sensorimotor) memory or through the interference of different task sets for closed-loop and open-loop feedback that determine when the movements are fully specified. We reasoned that sensorimotor memory, but not a task set for closed and open loop feedback, would be specific to the type of response. We tested this prediction in a condition in which pointing to targets was alternated with grasping those same targets. Critically, in this condition, when pointing was performed in open loop, grasping was always performed in closed loop (and vice versa). Despite the fact that closed- and open-loop trials were alternating in this condition, we found no evidence for homogenization of the PGA. Homogenization did occur, however, in a follow-up experiment in which grasping movements and visual feedback were alternated between the left and the right

  12. Reviews Book: Visible Learning Book: Getting to Grips with Graphs Book: A Teacher's Guide to Classroom Research Book: Relativity: A Graphic Guide Book: The Last Man Who Knew Everything Game: Planet Quest Equipment: Minoru 3D Web Camera Equipment: Throwies Equipment: Go Science Optics Kit Web Watch

    NASA Astrophysics Data System (ADS)

    2009-05-01

    WE RECOMMEND Visible Learning A compilation of more than 800 meta-analyses of achievement A Teacher's Guide to Classroom Research A useful aid for teachers who want to improve standards in class The Last Man Who Knew Everything This biography of Thomas Young is a 'lucid account' of his life Novo Minoru 3D Web Camera Welcome a mini alien to your classroom for fun 3D lessons WORTH A LOOK Getting to Grips with Graphs A useful collection of worksheets for teaching about graphs Relativity: A Graphic Guide This book works best as a supplementary text on relativity Planet Quest A space board game that will engage younger children Throwies Make a torch and liven up lessons on conductors and insulators Go Science Optics Kit Do-it-yourself optics kit should be priced a little lower WEB WATCH This month we take a look at NASA's technology and education web pages, which offer a great selection of space-related topics and activities for young scientists

  13. Loosening pain's grip by tightening TRPV1-TRPA1 interactions.

    PubMed

    Weyer, Andy D; Stucky, Cheryl L

    2015-02-18

    TRPA1 and TRPV1 are ion channels crucial for pain sensation. In this issue of Neuron, Weng et al. (2015) demonstrate that the activity of TRPA1-TRPV1 heteromers is governed by Tmem100 and that disabling Tmem100 may be a novel pharmacologic strategy to combat pain.

  14. Quo vadimus: Coming to grips with the information world

    NASA Technical Reports Server (NTRS)

    Blados, Walter R.

    1991-01-01

    The new information-oriented culture in which we find ourselves has created new relationships, new stimulating and expanding opportunities, new methods of doing our work, and new environments in which we carry out our work. An integral part of the NASA aerospace research and development (R and D) process is the scientific and technical information (STI) associated with it; it is both a raw material (input) and a product (output) of this process. Within this process, the NASA STI Program is tasked to provide information management and services, to ensure that accurate and timely STI is generated and entered into an appropriate information service and made available in a usable form to those who have a need for it; in essence, a means to exploit both internal (NASA corporate) and pertinent external (other governmental/industrial/foreign) information to meet the requirements of the R and D community. To understand the STI Program management issues, it is critical to understand the role of the STI Program in the context of the R and D process. STI management must become part of the accepted culture of the R and D community, but it cannot become so unless adopted and accepted by it. A start should be made now to integrate the NASA STI Program into the R and D infrastructure, including funding and operational control. Within this infrastructure, we must obtain management commitment, review and produce policy reflecting the organizational status, allocate responsibilities, and set to work on implementing the true requirements of the R and D community.

  15. Get a Grip on Demographics with Geospatial Technology

    ERIC Educational Resources Information Center

    Raymond, Randall E.

    2009-01-01

    Aging school infrastructure, changing population dynamics, decreased funding, and increased accountability for reporting school success all require today's school business officials to combine a variety of disparate data sets into a coherent system that enables effective and efficient decision making. School business officials are required to: (1)…

  16. Polar Vortex Tightens Grip on U.S.

    MedlinePlus

    ... A polar vortex is bringing extreme cold and winds to the central and eastern United States this ... being warned to guard against frostbite and hypothermia. Wind chills could fall to 30 to 40 degrees ...

  17. Getting to Grips with Bricolage: A Personal Account

    ERIC Educational Resources Information Center

    Wibberley, Christopher

    2012-01-01

    This paper presents a personal account of how a PhD supervisor came to an understanding of an approach to research that was unfamiliar to him. Additionally it addresses the question of what makes the approach, in this case bricolage, an acceptable format for academic work and in particular PhD study. Bricolage is a relatively little used approach…

  18. In the grip of the big telescope age

    NASA Astrophysics Data System (ADS)

    Devorkin, David H.

    2009-08-01

    George Ellery Hale was a man of many dreams. One of his most persistent was to find the means to collect as much light as possible, but there is another element in his designs for the modern astrophysical observatory that has even greater significance, as it defines and distinguishes the practice of astrophysics from that of classical astronomy. Here we examine factors that either impeded or drove the acceptance of reflectors over refractors around the turn of the twentieth century at the outset of what may best be called the “Hale era.” This commenced in the late nineteenth century, when the first large multi-focus photographic reflectors emerged during the reign of the great refractors. It lasted through to the onset of World War II when astronomical practice was dominated by ten reflectors with mirrors between 60 and 100 in., and was about to add one more whose surface area would almost double that of all the rest combined. We will touch upon how design choice reflected both scientific priorities and technological limitations.

  19. Coming to grips with autism: Parents engaging with science

    NASA Astrophysics Data System (ADS)

    Feinstein, Noah Robert

    When and how does science matter to people in their everyday lives? In this dissertation, I explore the importance of science to parents of young children recently diagnosed with autism. I examine the questions parents ask and the resources they use as they attempt to understand and advocate for their children, and use this data to develop a new conceptual model of engagement with science: the intrapersonal and interpersonal process through which people connect science with their lived experience. I recruited a socio-economically diverse sample of ten parents, each with at least one young child (18 months--7 years) who had been diagnosed with autism 6--24 months prior to recruitment. Each parent completed a series of 8--12 semi-structured interviews over a period of approximately six months. These interviews were analyzed using both grounded theory and conceptually driven coding strategies. Two findings stand out. First, only a small fraction of parents' questions (15%) and resources (11%) were directly related to science. A much larger fraction (41% and 42%) fell into the broader categories of near-science questions and resources. Second, half of the parents demonstrated an iterative pattern of activity that I referred to as progressive engagement with science. In each case, a science or near-science question led the parent to a science or near-science resource, which transformed the question. The new question led to different science or near-science resources, which led to new questions and so forth. Parents who did not undertake progressive engagement with science were also less interested in autism as an organizing construct for understanding their children. Drawing on the work of Peter Galison, I propose that the idea of autism helps create a "trading zone" between the distinct social systems of family life and medical science. Parents who ask near-science questions must find near-science resources to help them direct their questions appropriately. They must also re-articulate the answers in terms that are personally meaningful. Even when parents and doctors disagree on the meaning and significance of an autism diagnosis, their mutual investment in the idea of autism fosters conceptual "trading" and enables future engagement with science.

  20. RNA-directed DNA methylation: getting a grip on mechanism.

    PubMed

    Bender, Judith

    2012-05-22

    Small RNAs guide repressive chromatin modifications to regions of the genome containing transposons and repeats. An Arabidopsis genetic screen reveals that the guidance machinery includes a novel ATPase complex that could act as a dynamic molecular gripper.

  1. University Knowledge Production and Innovation: Getting a Grip

    ERIC Educational Resources Information Center

    van Rooij, Arjan

    2014-01-01

    Today universities are increasingly seen as motors of innovation: they not only need to provide trained manpower and publications to society, but also new products, new processes and new services that create firms, jobs, and economic growth. This function of universities is controversial, and a huge and still expanding literature has tried to…

  2. Getting to grips with the obesity epidemic in Europe.

    PubMed

    Cuschieri, Sarah; Mamo, Julian

    2016-01-01

    Obesity is a global epidemic. It is responsible for increased patient morbidity and mortality. Significant related pathologies including diabetes mellitus compound the overall risks. Obesity is a significant financial burden. This includes direct and indirect medical costs, amounting to millions of euros each year. Multiple European studies have outlined a steady incline in obesity prevalence rates. Tackling obesity is no easy task. Policy makers aiming to reduce obesity rates should adopt an evidence-based approach. This entails adopting both micro- and macro-interventions tweaked to each country's individual requirements. The ideal way forward would be to tackle obesity from the individual, population-wide and food industry angles. The key towards a successful intervention is for each country to carry out well-planned health examination studies, in an attempt to pin point local risk factors. Having a correct individualized picture, each country can move forward and draw policies and interventional procedures. The aim should be to primarily improve the quality of life. Second, the country's capital expenditure is also reduced.

  3. Getting to grips with the obesity epidemic in Europe

    PubMed Central

    Cuschieri, Sarah; Mamo, Julian

    2016-01-01

    Obesity is a global epidemic. It is responsible for increased patient morbidity and mortality. Significant related pathologies including diabetes mellitus compound the overall risks. Obesity is a significant financial burden. This includes direct and indirect medical costs, amounting to millions of euros each year. Multiple European studies have outlined a steady incline in obesity prevalence rates. Tackling obesity is no easy task. Policy makers aiming to reduce obesity rates should adopt an evidence-based approach. This entails adopting both micro- and macro-interventions tweaked to each country’s individual requirements. The ideal way forward would be to tackle obesity from the individual, population-wide and food industry angles. The key towards a successful intervention is for each country to carry out well-planned health examination studies, in an attempt to pin point local risk factors. Having a correct individualized picture, each country can move forward and draw policies and interventional procedures. The aim should be to primarily improve the quality of life. Second, the country’s capital expenditure is also reduced. PMID:27708778

  4. Global Hawk instrument installation for GRIP hurricane mission

    NASA Video Gallery

    Technicians from NASA's Jet Propulsion Laboratory, Ames and Goddard field centers prepare and install specialized environmental monitoring instrumentation on NASA's Global Hawk No. 872 at the Dryde...

  5. The Southern Ocean's Grip on the Northward Meridional Flow

    NASA Astrophysics Data System (ADS)

    Nof, D.

    2002-12-01

    Recently, a "quasi-island" approach for examining the meridional flux of warm and intermediate water from the Southern Ocean into the South Atlantic, the South Pacific and the Indian Ocean was proposed. The method considers the continents to be "pseudo islands" in the sense that they are entirely surrounded by water but have no circulation around them. The method employs an integration of the linearized momentum equations along a closed contour containing the continents. This allows one to compute the meridional transport into these oceans without finding the detailed solution to the complete wind-thermohaline problem. The solution gives one expected and one unexpected result. It shows that, as expected, about 9 ñ 5 Sv of upper and intermediate water enter the South Atlantic from the Southern Ocean. It also shows, however, the unexpected result that the Pacific-Indian Ocean system should contain a "shallow" meridional overturning cell carrying 18 ñ 5 Sv. By "shallow" it is meant here that the cell does not extend all the way to the bottom (as it does in the Atlantic) but is terminated at mid-depth. (This reflects the fact that there is no bottom water formation in the Pacific.) Both of these calculations rely on the observation that there is almost no flow through the Bering Strait and on the assumption that there is a negligible pressure torque on the Bering Strait's sill. Here, we present a new and different approach which does not rely on the above two conditions regarding the Bering Strait and yet gives essentially the same result. The approach does not involve any quasi-island calculation but rather employs an integration of the linearized zonal momentum equation along a closed open-water latitudinal belt connecting the tips of South Africa and South America. The integration relies on the existence of a belt (corridor) where the linearized general circulation equations are valid. It allows for a net northward mass flux through either the Sverdrup interior or the western boundary currents. It is found that the belt-corridor approach gives 29 ñ 5 Sv for the total meridional flux of surface and intermediate water from the Southern Ocean. This agrees very well with the above-mentioned quasi-island calculations which give a total northward flux of 27 ñ 5 Sv. Given the spacing between the continents and the small variability of the southern winds with longitude, one may assume that out of the 29 Sv, 9 Sv enter the Atlantic and 20 Sv enter the combined Pacific-Indian Ocean system which is also in agreement with the quasi-island calculation. These agreements indicate that the assumptions made in the earlier studies regarding the Bering Strait are probably valid.

  6. Grip Force Coordination during Bimanual Tasks in Unilateral Cerebral Palsy

    ERIC Educational Resources Information Center

    Islam, Mominul; Gordon, Andrew M.; Skold, Annika; Forssberg, Hans; Eliasson, Ann-Christin

    2011-01-01

    Aim: The aim of the study was to investigate coordination of fingertip forces during an asymmetrical bimanual task in children with unilateral cerebral palsy (CP). Method: Twelve participants (six males, six females; mean age 14y 4mo, SD 3.3y; range 9-20y;) with unilateral CP (eight right-sided, four left-sided) and 15 age-matched typically…

  7. Grip and detachment of locusts on inverted sandpaper substrates.

    PubMed

    Han, Longbao; Wang, Zhouyi; Ji, Aihong; Dai, Zhendong

    2011-12-01

    Locusts (Locusta migratoria manilensis) are characterized by their strong flying and grasping ability. Research on the grasping mechanism and behaviour of locusts on sloping substrates plays an important role in elucidating the mechanics of hexapod locomotion. Data on the maximum angles of slope at which locusts can grasp stably (critical angles of detachment) were obtained from high-speed video recordings at 215 fps. The grasping forces were collected by using two sensors, in situations where all left legs were standing on one and the right legs on the other sensor plate. These data were used to illustrate the grasping ability of locusts on slopes with varying levels of roughness. The grasping morphologies of locusts' bodies and tarsi were observed, and the surface roughness as well as diameters of their claw tips was measured under a microscope to account for the grasping mechanism of these insects on the sloping substrate. The results showed that the claw tips and part of the pads were in contact with the inverted substrate when the mean particle diameter was in the range of 15.3-40.5 µm. The interaction between pads and substrates may improve the stability of contact, and claw tips may play a key role in keeping the attachment reliable. A model was developed to explain the significant effects of the relative size of claw tips and mean particle diameter on grasping ability as well as the observed increase in lateral force (2.09-4.05 times greater than the normal force during detachment) with increasing slope angle, which indicates that the lateral force may be extremely important in keeping the contact reliable. This research lays the groundwork for the probable design and development of biomimetic robotics.

  8. Getting to Grips with On-the-Job Competencies.

    ERIC Educational Resources Information Center

    Foyster, John

    This booklet is one in a series that has been written for the general reader who wants to understand important trends in vocational education and training in Australia. Its focus is competency-based training and assessment. The booklet starts with the specific working environment of a blackjack dealer in a casino and explores the meaning of…

  9. What to Do When Winter Has You in its Icy Grip

    MedlinePlus

    ... conditions are caused by excessive exposure to low temperatures, wind or moisture. Cold weather can be dangerous ... outside in winter, be sure to: Check the temperature and limit your time outdoors if it's very ...

  10. The Relationship of Isometric Grip Strength, Optimal Dynamometer Settings, and Certain Anthropometric Factors

    DTIC Science & Technology

    1990-05-01

    though the field of human factor engineering has included various thicknesses and depths (Davies, Abada , Benson, Courtney, & Minto, 1980; Garrett...337. Comas, J. (1960). Manual of physical anthropology. Springfield, IL: Charles C. Thomas. Davies, B. T., Abada , A., Benson, K., Courtney, A

  11. Grip it and rip it: structural mechanisms of DNA helicase substrate binding and unwinding.

    PubMed

    Bhattacharyya, Basudeb; Keck, James L

    2014-11-01

    Maintenance and faithful transmission of genomic information depends on the efficient execution of numerous DNA replication, recombination, and repair pathways. Many of the enzymes that catalyze steps within these pathways require access to sequence information that is buried in the interior of the DNA double helix, which makes DNA unwinding an essential cellular reaction. The unwinding process is mediated by specialized molecular motors called DNA helicases that couple the chemical energy derived from nucleoside triphosphate hydrolysis to the otherwise non-spontaneous unwinding reaction. An impressive number of high-resolution helicase structures are now available that, together with equally important mechanistic studies, have begun to define the features that allow this class of enzymes to function as molecular motors. In this review, we explore the structural features within DNA helicases that are used to bind and unwind DNA. We focus in particular on "aromatic-rich loops" that allow some helicases to couple single-stranded DNA binding to ATP hydrolysis and "wedge/pin" elements that provide mechanical tools for DNA strand separation when connected to translocating motor domains.

  12. [Variability of muscular and articular forces of the thumb. Comparison of three results during lateral grip].

    PubMed

    Lbath, F; Rumelhart, C; Comtet, J J

    2001-02-01

    The aim of this paper is to describe three different laboratory studies of muscular and articular forces in the thumb and to compare and discuss their results in term of constraints (forces and moments) at the carpometacarpal joint during key pinch. Imaging techniques such as biplanar roentgenograms or computer tomography imaging were used on cadaver hands and magnetic resonance imaging on living hands in order to determine bone dimensions, muscle and tendon forces, directions, and centres of rotation. Mechanical models of free bodies with three to five links were created. Problems of balancing of static forces were solved using different methods (electromyography, systematic combination of muscular forces or optimization method). The results in terms of muscular forces or constraints at the carpometacarpal joint showed a strong variability (one to three depending on method and hypothesis). However the three studies all showed subluxation of the carpometacarpal joint balanced by joint constraints. Finally, it was demonstrated using magnetic resonance imaging, that results were strongly influenced by the exact point of application of the forces.

  13. Getting a grip on glycans: A current overview of the metabolic oligosaccharide engineering toolbox.

    PubMed

    Sminia, Tjerk J; Zuilhof, Han; Wennekes, Tom

    2016-11-29

    This review discusses the advances in metabolic oligosaccharide engineering (MOE) from 2010 to 2016 with a focus on the structure, preparation, and reactivity of its chemical probes. A brief historical overview of MOE is followed by a comprehensive overview of the chemical probes currently available in the MOE molecular toolbox and the bioconjugation techniques they enable. The final part of the review focusses on the synthesis of a selection of probes and finishes with an outlook on recent and potential upcoming advances in the field of MOE.

  14. The Great Lakes Runoff Intercomparison Project Phase 1: Lake Michigan (GRIP-M)

    NASA Astrophysics Data System (ADS)

    Fry, Lauren M.; Gronewold, Andrew D.; Fortin, Vincent; Buan, Steven; Clites, Anne H.; Luukkonen, Carol; Holtschlag, David; Diamond, Laura; Hunter, Timothy; Seglenieks, Frank; Durnford, Dorothy; Dimitrijevic, Milena; Subich, Christopher; Klyszejko, Erika; Kea, Kandace; Restrepo, Pedro

    2014-11-01

    We assembled and applied five models (one of which included three different configurations) to the Lake Michigan basin to improve our understanding of how differences in model skill at simulating total runoff to Lake Michigan relate to model structure, calibration protocol, model complexity, and assimilation (i.e. replacement of simulated discharge with discharge observations into historical simulations), and evaluate historical changes in runoff to Lake Michigan. We found that the performance among these models when simulating total runoff to the lake varied relatively little, despite variability in model structure, spatial representation, input data, and calibration protocol. Relatively simple empirical, assimilative models, including the National Oceanic and Atmospheric Administration (NOAA) Great Lakes Environmental Research Laboratory (GLERL) area ratio-based model (ARM) and the United States Geological Survey (USGS) Analysis of Flows in Networks of CHannels (AFINCH) model, represent efficient and effective approaches to propagating discharge observations into basin-wide (including gaged and ungaged areas) runoff estimates, and may offer an opportunity to improve predictive models for simulating runoff to the Great Lakes. Additionally, the intercomparison revealed that the median of the simulations from non-assimilative models agrees well with assimilative models, suggesting that using a combination of different methodologies may be an appropriate approach for estimating runoff into the Great Lakes. We then applied one assimilative model (ARM) to the Lake Michigan basin and found that there was persistent reduction in the amount of precipitation that becomes runoff following 1998, corresponding to a period of persistent low Lake Michigan water levels. The study was conducted as a first phase of the Great Lakes Runoff Intercomparison Project, a regional binational collaboration that aims to systematically and rigorously assess a variety of models currently used (or that could readily be adapted) to simulate basin-scale runoff to the North American Laurentian Great Lakes.

  15. Structures of Two Arabidopsis thaliana Major Latex Proteins Represent Novel Helix-Grip Folds

    PubMed Central

    Lytle, Betsy L.; Song, Jikui; de la Cruz, Norberto B.; Peterson, Francis C.; Johnson, Kenneth A.; Bingman, Craig A.; Phillips, George N.; Volkman, Brian F.

    2010-01-01

    The major latex proteins (MLP) are a protein family first identified in the latex of opium poppy. They are found only in plants and have 24 identified members in Arabidopsis alone as well as in other plants such as peach, strawberry, melon, cucumber, and soybean. While the function of the MLPs is unknown, they have been associated with fruit and flower development and in pathogen defense responses. Based on modest sequence similarity, they have been characterized as members of the Bet v 1 protein superfamily; however, no structures have yet been reported. As part of an ongoing structural genomics effort, we determined the structures of two Arabidopsis thaliana MLPs: the solution structure of MLP28 (gene product of At1g70830.1) and the crystal structure of At1g24000.1. The structures revealed distinct differences when compared to one another and to the typical Bet v 1 fold. Nevertheless, NMR titration experiments demonstrated that the characteristic Bet v 1 hydrophobic binding pocket of At1g24000.1 is able to bind a ligand, suggesting that it plays a role in the function of the MLPs. A structure-based sequence analysis identified conserved hydrophobic residues in the long alpha helix that contribute to the binding cavity and may specify preferred ligands for the MLP family. PMID:19326460

  16. Keeping a tight grip on the reins: donor control over aid coordination and management in Bangladesh.

    PubMed

    Buse, K

    1999-09-01

    A long-standing consensus that aid coordination should be owned by recipient authorities has been eclipsed by accord on the desirability of recipient management of aid along-side domestic resources. Nonetheless, in many low and lower-middle income countries, donors remain remarkably uncoordinated; where attempts at coordination are made, they are often donor-driven, and only a small proportion of aid is directly managed by recipients. This paper draws on evidence from an in-depth review of aid to the health sector in Bangladesh to analyze the systems by which external resources are managed. Based on interviews with key stakeholders, a questionnaire survey and analysis of documentary sources, the factors constraining the government from assuming a more active role in aid management are explored. The results suggest that donor perceptions of weak government capacity, inadequate accountability and compromised integrity only partially account for the propensity for donor leadership. Equally important is the consideration that aid coordination has a markedly political dimension. Stakeholders are well aware of the power, influence and leverage which aid coordination confers, an awareness which colours the desire of some stakeholders to lead aid coordination processes, and conditions the extent and manner by which others wish to be involved. It is argued that recipient management of external aid is dependent on major changes in the attitudes and behaviours of recipients and donors alike.

  17. Placebo treatments, informed consent and 'the grip of a false picture'.

    PubMed

    Glackin, Shane Nicholas

    2015-08-01

    It is widely supposed that the prescription of placebo treatments to patients for therapeutic purposes is ethically problematic on the grounds that the patient cannot give informed consent to the treatment, and is therefore deceived by the physician. This claim, I argue, rests on two confusions: one concerning the meaning of 'informed consent' and its relation to the information available to the patient, and another concerning the relation of body and mind. Taken together, these errors lead naturally to the conclusion that the prescription of placebos to unwitting patients is unethical. Once they are dispelled, I argue, we can see that providing 'full' information against a background of metaphysical confusion may make a patient less informed and that the 'therapeutic' goal of relieving the patient of such confusions is properly the duty of the philosopher rather than the physician. Therapeutic placebos therefore do not violate the patient's informed consent or the ethical duties of the doctor.

  18. A gripping tale of ribosomal frameshifting: extragenic suppressors of frameshift mutations spotlight P-site realignment.

    PubMed

    Atkins, John F; Björk, Glenn R

    2009-03-01

    Mutants of translation components which compensate for both -1 and +1 frameshift mutations showed the first evidence for framing malleability. Those compensatory mutants isolated in bacteria and yeast with altered tRNA or protein factors are reviewed here and are considered to primarily cause altered P-site realignment and not altered translocation. Though the first sequenced tRNA mutant which suppressed a +1 frameshift mutation had an extra base in its anticodon loop and led to a textbook "yardstick" model in which the number of anticodon bases determines codon size, this model has long been discounted, although not by all. Accordingly, the reviewed data suggest that reading frame maintenance and translocation are two distinct features of the ribosome. None of the -1 tRNA suppressors have anticodon loops with fewer than the standard seven nucleotides. Many of the tRNA mutants potentially affect tRNA bending and/or stability and can be used for functional assays, and one has the conserved C74 of the 3' CCA substituted. The effect of tRNA modification deficiencies on framing has been particularly informative. The properties of some mutants suggest the use of alternative tRNA anticodon loop stack conformations by individual tRNAs in one translation cycle. The mutant proteins range from defective release factors with delayed decoding of A-site stop codons facilitating P-site frameshifting to altered EF-Tu/EF1alpha to mutant ribosomal large- and small-subunit proteins L9 and S9. Their study is revealing how mRNA slippage is restrained except where it is programmed to occur and be utilized.

  19. The assessment of grip strength after upper limb injuries in medico-legal practice.

    PubMed

    Belcher, Hjcr

    2017-03-01

    Four hundred adult claimants underwent medico-legal assessment following upper limb injuries. Dynamometry was performed on each using the Jamar five handle-position test. Injury causes loss of power and there is a significant relationship between the percentage loss of power and the measured whole limb impairment. This paper presents a new approach for the analysis of the tests. The normal physiological length-tension pattern of muscle is maintained in the majority of claimants albeit with modifications due to the specific effects of injury on hand function. This paper provides normative data for the analysis of dynamometry in this population and makes recommendations for parameters that suggest that a test is a true reflection of capacity and thus useable in court.

  20. Getting a Grip on the Classroom: From Psychological to Phenomenological Curriculum Development in Teacher Education Programs

    ERIC Educational Resources Information Center

    Garcia, Justin A.; Lewis, Tyson E.

    2014-01-01

    A major field of psychological research in education concerns the relationship between teachers' beliefs and their practices. A contested yet fairly consistent assumption underlying this literature is that the beliefs that teachers hold concerning the educational profession directly and/or indirectly affect their practices in actual…

  1. Recession becomes major force to tighten grip on quarterly gas pipeline building costs

    SciTech Connect

    Morgan, J.M.

    1983-04-25

    This article points out that the major force affecting gas pipeline building costs, during the second quarter of 1982, was the recession. The total composite cost index for building gas pipelines increased by only 1.01%. Material prices for steel line pipe, valves, fittings, and line pipe coating showed little or no gain during the period. Installation labor costs continued to climb. Discusses construction activity, compressor equipment and drive units, and high pressure gas station piping.

  2. Get a grip on chaos: Tailored measures for complex systems on surfaces

    NASA Astrophysics Data System (ADS)

    Firle, Sascha Oliver

    Complex systems are ubiquitous in physics, biology and mathematics. This thesis is concerned with describing and understanding complex systems. Some new concepts about how large systems can be viewed in a lower dimensional framework are proposed. The systems presented are examples from ecology and chemistry. In both cases we have a large amount of interacting units that can be understood by The predator-prey system investigated consists of ground beetles, Pterostichus cuprens L. (Coleoptera: Carabidae), that feeds on bird-cherry oat aphids. The beetles' movement can consistently be described by a combined model of surface diffusion and biased random walk. This allows conclusions about how fast and in which fashion the beetle covers its habitat. Movement is dependent on aphid densities and predation, in turn modifies aphid distributions locally. The presented generalized functional response theory describes predation rates in the presence of spatial heterogeneity. A single measure for fragmentation captures all essential features of the prey aggregation and allows the estimation of outbreak densities and distributions. The chemical example is the catalytic oxidation of CO on a Pt(110) single crystal surface. Unstable periodic orbits reconstructed from experimental data are used to reveal the topology of the attractor, underlying the time series dynamics. The found braid supports an orbit which implies that the time series is chaotic. The system is simulated numerically by a set of partial differential equations for surface coverage in one space dimension. The bifurcation diagram of the corresponding traveling wave ODE reveals the homoclinic and heteroclinic orbits that organize the phase space and mediate the transition to chaos. Studies in the PDE- framework relate this to the stability and to the interaction of pulse-like solutions.

  3. "Thinking Things Through": Coming to Grips with Philosophical and Prudential Perspectives in Teachers' Educational Practice.

    ERIC Educational Resources Information Center

    Husa, Jukka

    This paper examines what pedagogical issues mean to practicing teachers, discussing the ethics of purpose, rules and principles, and probability, and noting teachers' philosophical perspectives and practical interpretations. Interviews were conducted with 20 Finnish secondary school teachers working in urban schools during an in-service training…

  4. Evidence for Motor Planning in Monkeys: Rhesus Macaques Select Efficient Grips when Transporting Spoons

    ERIC Educational Resources Information Center

    Nelson, Eliza L.; Berthier, Neil E.; Metevier, Christina M.; Novak, Melinda A.

    2011-01-01

    McCarty and colleagues (1999) developed the elevated spoon task to measure motor planning in human infants. In this task, a spoon containing food was placed on an elevated apparatus that supported both ends of the spoon. The handle was oriented to the left or right on different trials. We presented naive adult rhesus monkeys (Macaca mulatta) with…

  5. Infants' Grip Strength Predicts Mu Rhythm Attenuation during Observation of Lifting Actions with Weighted Blocks

    ERIC Educational Resources Information Center

    Upshaw, Michaela B.; Bernier, Raphael A.; Sommerville, Jessica A.

    2016-01-01

    Research has established that the body is fundamentally involved in perception: bodily experience influences activation of the shared neural system underlying action perception and production during action observation, and bodily characteristics influence perception of the spatial environment. However, whether bodily characteristics influence…

  6. Effect of bandwidth knowledge of results on the learning of a grip force control task.

    PubMed

    Ugrinowitsch, Herbert; Ugrinowitsch, Alessandra Aguilar Coca; Benda, Rodolfo Novellino; Tertuliano, Ivan Wallan

    2010-12-01

    An experiment was conducted to investigate the persistence of the effect of "bandwidth knowledge of results (KR)" manipulated during the learning phase of performing a manual force-control task. The experiment consisted of two phases, an acquisition phase with the goal of maintaining 60% maximum force in 30 trials, and a second phase with the objective of maintaining 40% of maximum force in 20 further trials. There were four bandwidths of KR: when performance error exceeded 5, 10, or 15% of the target, and a control group (0% bandwidth). Analysis showed that 5, 10, and 15% bandwidth led to better performance than 0% bandwidth KR at the beginning of the second phase and persisted during the extended trials.

  7. Structures of two Arabidopsis thaliana major latex proteins represent novel helix-grip folds

    SciTech Connect

    Lytle, Betsy L.; Song, Jikui; de la Cruz, Norberto B.; Peterson, Francis C.; Johnson, Kenneth A.; Bingman, Craig A.; Phillips, Jr., George N.; Volkman, Brian F.

    2009-06-02

    Here we report the first structures of two major latex proteins (MLPs) which display unique structural differences from the canonical Bet v 1 fold described earlier. MLP28 (SwissProt/TrEMBL ID Q9SSK9), the product of gene At1g70830.1, and the At1g24000.1 gene product (Swiss- Prot/TrEMBL ID P0C0B0), proteins which share 32% sequence identity, were independently selected as foldspace targets by the Center for Eukaryotic Structural Genomics. The structure of a single domain (residues 17-173) of MLP28 was solved by NMR spectroscopy, while the full-length At1g24000.1 structure was determined by X-ray crystallography. MLP28 displays greater than 30% sequence identity to at least eight MLPs from other species. For example, the MLP28 sequence shares 64% identity to peach Pp-MLP119 and 55% identity to cucumber Csf2.20 In contrast, the At1g24000.1 sequence is highly divergent (see Fig. 1), containing a gap of 33 amino acids when compared with all other known MLPs. Even when the gap is excluded, the sequence identity with MLPs from other species is less than 30%. Unlike some of the MLPs from other species, none of the A. thaliana MLPs have been characterized biochemically. We show by NMR chemical shift mapping that At1g24000.1 binds progesterone, demonstrating that despite its sequence dissimilarity, the hydrophobic binding pocket is conserved and, therefore, may play a role in its biological function and that of the MLP family in general.

  8. The 6,000 Mile Screwdriver is Getting Longer: Washington’s Strengthening Grip

    DTIC Science & Technology

    2012-04-01

    Year in Iraq: the Struggle to Build a Future of Hope (New York: Simon & Schuster, 2006), 186-187. 40 Bremer, 104-5. 41 Jon Anderson, ―‗Screwdriver...Odierno_assumes_command_of_coalition_forces_in_Iraq/. 56 Thomas P.M. Barnett , ―The Man Between War and Peace,‖ Esquire, April 2008. Accessed January

  9. Grips and ties: agency, uncertainty, and the problem of suffering in North Karelia.

    PubMed

    Honkasalo, Marja-Liisa

    2009-03-01

    In medical anthropological research, the question of suffering has been a topic of salient interest mostly from two theoretical viewpoints: those of endurance and of agency. The concept "suffering" derives its origins from two etymological roots, those of suffering-souffrance-sofferanza and of misery-misère-miseria. According to the first approach, that of "endurance" and founded largely on Judeo-Christian theology, suffering is regarded as an existential experience at the borders of human meaning making. The question then is: how to endure, how to suffer? The latter view, that of "agency," follows the Enlightenment, and later the Marxist view on mundane suffering, misery, and the modern question of how to avoid or diminish it. This article follows the lines of the second approach, but my aim is also to try to build a theoretical bridge between the two. I ask whether agency would be understood as a culturally shared and interpreted modes of enduring, and if so, which conceptual definition of agency applies in this context? I theorize the relationship between suffering and agency using Ernesto de Martino's notion la crisi della presenza. In line with Pierre Bourdieu, I think that in people's lives, there may be sufferings in a plural form, as a variety of sufferings. The article is based on a one-year long fieldwork in Finnish North Karelia.

  10. Getting a grip on systems of care and child welfare using opposable thumbs.

    PubMed

    Fluke, John D; Oppenheim, Elizabeth

    2010-02-01

    The purpose of this response paper is to discuss issues raised by two of the components of the definition of systems of care proffered by Hodges et al. [Hodges, S., Ferreira, K., Israel, N., & Mazza, J. (this issue). Systems of care, featherless bipeds, and the measure of all things. Evaluation and Program Planning]. In particular, this response will present some implications of the definition of the focus population and the value and core principle of family-driven care. It will also consider why these two components of the definition might serve as challenges to the applicability of the concept of systems of care to child welfare, and, in turn, integration of the model across child welfare and mental health. Recommendations for expanding and refining these component terms are provided.

  11. Coming to Grips with Change: The Initial Training of Geography Teachers in Hong Kong

    ERIC Educational Resources Information Center

    Stimpson, Philip

    2004-01-01

    Hong Kong styles itself as "the city that never sleeps", "the ever changing city". The dynamism and pace of change in teacher education, however, has to be seen as laggardly in comparison. This is not to say there has been no experiment but changes have been piecemeal and "add-ons". Teacher education in Hong Kong has…

  12. NUTRITIONAL ASSESSMENT AND HAND GRIP STRENGTH OF CANDIDATES FOR SURGERY OF THE GASTROINTESTINAL TRACT

    PubMed Central

    SILVEIRA, Thalita Morgana Guimarães; de SOUSA, Juliana Barbosa; STRINGHINI, Maria Luiza Ferreira; FREITAS, Ana Tereza Vaz de Souza; MELO, Paulla Guimarães

    2014-01-01

    Background The assessment of nutritional status in clinical practice must be done with simple, reliable, low cost and easy performance methods. The power of handshake is recognized as a useful tool to evaluate muscle strength, and therefore, it is suggested that can detect malnutrition. Aim To evaluate the nutritional status by subjective global assessment and power of handshake preoperatively in patients going to gastrointestinal surgeries and to compare the diagnosis obtained by subjective global assessment with traditional anthropometric methods and power of handshake. Methods A cross-sectional study was conducted with patients for surgery in the gastrointestinal tract and related organs. Socioeconomic and anthropometric data, applied to subjective global assessment and checked the power of handshake, were collected. The force was obtained by the average of three measurements of the dominant and non-dominant hand and thus compared with reference values ​​of the population by sex and age, for the classification of nutritional risk. Results The sample consisted of 40 patients, 24-83 years, and most women (52.5%) housewives (37,5%) and diagnosed with cancer (45%). According to subjective global assessment, 37.5% were classified as moderately malnourished; 15% were underweight by BMI measurements; 25% had arm circumference at risk for malnutrition (

  13. The Southern Ocean’s grip on the northward meridional flow

    NASA Astrophysics Data System (ADS)

    Nof, D.

    2003-02-01

    A ‘quasi-island’ approach for examining the meridional flux of warm and intermediate water from the Southern Ocean into the South Atlantic, the South Pacific and the Indian Ocean has recently been proposed ( Nof, 2000a, 2002). This approach considers the continents to be ‘pseudo islands’ in the sense that they are entirely surrounded by water, but have no circulation around them. The method employs an integration of the linearized momentum equations along a closed contour containing the continents. This allows the meridional transport into these oceans to be computed without having to find the detailed solution to the complete wind-thermohaline problem. The solution gives two results; one expected, the other unexpected. It shows that, as expected, about 9±5 Sv of upper and intermediate water enter the South Atlantic from the Southern Ocean. The unexpected result is that the Pacific-Indian Ocean system should contain a ‘shallow’ meridional overturning cell carrying 18±5 Sv. What is meant by shallow here is that the cell does not extend all the way to the bottom (as it does in the Atlantic) but is terminated at mid-depth. (This reflects the fact that there is no bottom water formation in the Pacific.) Both of these calculations rely on the observation that there is almost no flow through the Bering Strait and on the assumption that there is a negligible pressure torque on the Bering Strait’s sill. Here, we present a new and different approach, which does not rely on either of the above two conditions regarding the Bering Strait and yet gives essentially the same result. The approach does not involve any quasi-island calculation but rather employs an integration of the linearized zonal momentum equation along a closed open-water latitudinal belt connecting the tips of South Africa and South America. The integration relies on the existence of a belt (corridor) where the linearized general circulation equations are valid. It allows for a net northward mass flux through either the Sverdrup interior or the western boundary currents. It is found that the belt-corridor approach gives 29±5 Sv for the total meridional flux of surface and intermediate water from the Southern Ocean. This agrees very well with the quasi-island calculations, which give a total northward flux of 27±5 Sv. Given the spacing between the continents and the small variability of the southern winds with longitude, one may assume that 9 Sv of the total 29 Sv enters the Atlantic and the other 20 Sv enters the combined Pacific-Indian Ocean system, which is also in agreement with the quasi-island calculation. These agreements indicate that the assumptions made in the earlier studies regarding the Bering Strait are probably valid.

  14. The Effect of Climbing Wall Use on the Grip Strength of Fourth-Grade Students

    ERIC Educational Resources Information Center

    Lirgg, Cathy D.; Dibrezzo, Ro; Gray, Michelle; Esslinger, Travis

    2011-01-01

    Physical educators are challenged to provide quality experiences that are fun for their students, enhance fitness levels, and build confidence. These challenges are amplified with the current decrease in activity levels of American youth. A possible solution to enhancing physical activity engagement in children is to incorporate climbing walls…

  15. Getting to grips with the cannabis problem: the evolving contributions and impact of Griffith Edwards.

    PubMed

    Hall, Wayne

    2015-07-01

    Griffith Edwards played an important role in cannabis policy debates within government advisory committees in the United Kingdom from the early 1970s until the early 1980s. This has largely been hidden from public knowledge by the confidentiality of these committee discussions. The purpose of this paper is to use Griffith's writings and the results of recent historical scholarship to outline the views he expressed, the reasons he gave for them, and to provide a brief assessment of his contribution to the development of British cannabis policy.

  16. Loss of Muscle Mass is Poorly Reflected in Grip Strength Performance in Healthy Young Men

    DTIC Science & Technology

    1994-01-01

    ex- to position their shoulder over the elbow, keeping the tending at the knee and hip . He then racks the weight by elbow joint at approximately 90...ob- Testing procedures. Body composition (measured tained at the start of this study was the average measure- by dual energy x-ray absorptiometry, DEXA ...previously demonstrated in soldiers (20). 7-10 d of simulated combat patrols). The average daily Fat-free mass (FFM) was measured using DEXA energy

  17. Getting to Grips with Mathematically Tricky Electric, Magnetic and Electromagnetic Fields.

    ERIC Educational Resources Information Center

    Moore, Guy S. M.

    1990-01-01

    Discusses when alternating and magnetic fields are independent. Provides examples of experiments involving mains hum and the detection of induced signals. Describes electric circuits and oscilloscope displays. (Author/YP)

  18. Influence on grip of knife handle surface characteristics and wearing protective gloves.

    PubMed

    Claudon, Laurent

    2006-11-01

    Ten subjects were asked to apply maximum torques on knife handles with either their bare hand or their hand wearing a Kevlar fibre protective glove. Four knife handles (2 roughnesses, 2 hardnesses) were tested. Surface electromyograms of 6 upper limb and shoulder muscles were recorded and subject opinions on both knife handle hardness and friction in the hand were also assessed. The results revealed the significant influence of wearing gloves (p<0.0001), knife type (p<0.0005) and handle hardness (p<0.005) on the applied torque. Wearing Kevlar fibre gloves greatly increased the torque independently of the other two parameters. Under the bare hand condition, a 90 degrees ShA slightly rough handle provided the greatest torque. Subject opinion agreed with the observed effects on recorded torque values except for the hardness factor, for which a preference for the 70 degrees ShA value over the 90 degrees ShA value emerged.

  19. The New Wave of Childhood Studies: Breaking the Grip of Bio-Social Dualism?

    ERIC Educational Resources Information Center

    Ryan, Kevin William

    2012-01-01

    The article takes as its starting point a new wave of researchers who use concepts such as "hybridity" and "multiplicity" in a bid to move the study of childhood beyond the strictures of what Lee and Motzkau call "bio-social dualism", whereby the division between the "natural child" of developmental psychology and the "social child" of…

  20. Getting a grip on the transverse motion in a Zeeman decelerator

    SciTech Connect

    Dulitz, Katrin; Softley, Timothy P.; Motsch, Michael; Vanhaecke, Nicolas

    2014-03-14

    Zeeman deceleration is an experimental technique in which inhomogeneous, time-dependent magnetic fields generated inside an array of solenoid coils are used to manipulate the velocity of a supersonic beam. A 12-stage Zeeman decelerator has been built and characterized using hydrogen atoms as a test system. The instrument has several original features including the possibility to replace each deceleration coil individually. In this article, we give a detailed description of the experimental setup, and illustrate its performance. We demonstrate that the overall acceptance in a Zeeman decelerator can be significantly increased with only minor changes to the setup itself. This is achieved by applying a rather low, anti-parallel magnetic field in one of the solenoid coils that forms a temporally varying quadrupole field, and improves particle confinement in the transverse direction. The results are reproduced by three-dimensional numerical particle trajectory simulations thus allowing for a rigorous analysis of the experimental data. The findings suggest the use of a modified coil configuration to improve transverse focusing during the deceleration process.

  1. Inferior frontal gyrus links visual and motor cortices during a visuomotor precision grip force task.

    PubMed

    Papadelis, Christos; Arfeller, Carola; Erla, Silvia; Nollo, Giandomenico; Cattaneo, Luigi; Braun, Christoph

    2016-11-01

    Coordination between vision and action relies on a fronto-parietal network that receives visual and proprioceptive sensory input in order to compute motor control signals. Here, we investigated with magnetoencephalography (MEG) which cortical areas are functionally coupled on the basis of synchronization during visuomotor integration. MEG signals were recorded from twelve healthy adults while performing a unimanual visuomotor (VM) task and control conditions. The VM task required the integration of pinch motor commands with visual sensory feedback. By using a beamformer, we localized the neural activity in the frequency range of 1-30Hz during the VM compared to rest. Virtual sensors were estimated at the active locations. A multivariate autoregressive model was used to estimate the power and coherence of estimated activity at the virtual sensors. Event-related desynchronisation (ERD) during VM was observed in early visual areas, the rostral part of the left inferior frontal gyrus (IFG), the right IFG, the superior parietal lobules, and the left hand motor cortex (M1). Functional coupling in the alpha frequency band bridged the regional activities observed in motor and visual cortices (the start and the end points in the visuomotor loop) through the left or right IFG. Coherence between the left IFG and left M1 correlated inversely with the task performance. Our results indicate that an occipital-prefrontal-motor functional network facilitates the modulation of instructed motor responses to visual cues. This network may supplement the mechanism for guiding actions that is fully incorporated into the dorsal visual stream.

  2. Getting a Grip on Memory: Unilateral Hand Clenching Alters Episodic Recall

    DTIC Science & Technology

    2013-04-24

    Electroencephalographic ( EEG ) measures demonstrate that a mere 90 seconds of left hand clenching increases right hemisphere activity, and similar right...However, to our knowledge no research has examined cognition , and in particular memory processing, as a function of hemispheric activation induced via...contraction of hand muscles. Cortex 30: 247–254. 5. Davidson RJ (2002) Anxiety and affective style : Role of prefrontal cortex and amygdala. Biol Psychiatry

  3. Coming to Grips with Your Finances. Home Study Course. Misc. Series No. 112.

    ERIC Educational Resources Information Center

    Lawroski, Mary Ann; Shinn, Marilyn C.

    This set of lessons is designed as a home study course to help individuals come to terms with their finances. Lesson 1 explains the following steps in developing a financial action plan: determining priorities, setting financial goals, analyzing cash flow, planning spending, developing spending guidelines, making written spending plans, planning…

  4. Hotspot or Heatwave? Getting to Grips with Neutron Star Burst Oscillations

    NASA Technical Reports Server (NTRS)

    Watts, A.

    2005-01-01

    Many accreting neutron stars, including two of the millisecond pulsars, exhibit high frequency oscillations during Type I X-ray bursts. The properties of the burst oscillations reflect the nature of the thermal asymmetry on the stellar surface. The mechanism that gives rise to the aspzetry, however , remains unclear: possibilities include a hotspot due to uneven fuel distribution, modes of oscillation in the surface layers of the neutron star, or vortices driven by the Coriolis force. I will review some of the latest theory and observations, and present the results of a recent study of variability in the burst oscillations of the millisecond pulsar 51814-338.

  5. People Getting a Grip on Arthritis: A Knowledge Transfer Strategy to Empower Patients with Rheumatoid Arthritis and Osteoarthritis

    ERIC Educational Resources Information Center

    Brosseau, Lucie; Lineker, Sydney; Bell, Mary; Wells, George; Casimiro, Lynn; Egan, Mary; Cranney, Ann; Tugwell, Peter; Wilson, Keith G.; De Angelis, Gino; Loew, Laurianne

    2012-01-01

    Objective: The purpose of this study was twofold. First, to help people with arthritis become aware of and utilize Rheumatoid Arthritis (RA) and Osteoarthritis (OA) Clinical Practice Guidelines (CPGs) as they relate to self-management strategies. Second, to evaluate the impact of specific Knowledge Translation (KT) activities on CPG uptake. More…

  6. Modeling the finger joint moments in a hand at the maximal isometric grip: the effects of friction.

    PubMed

    Wu, John Z; Dong, Ren G; McDowell, Thomas W; Welcome, Daniel E

    2009-12-01

    The interaction between the handle and operator's hand affects the comfort and safety of tool and machine operations. In most of the previous studies, the investigators considered only the normal contact forces. The effect of friction on the joint moments in fingers has not been analyzed. Furthermore, the observed contact forces have not been linked to the internal musculoskeletal loading in the previous experimental studies. In the current study, we proposed a universal model of a hand to evaluate the joint moments in the fingers during grasping tasks. The hand model was developed on the platform of the commercial software package AnyBody. Only four fingers (index, long, ring, and little finger) were included in the model. The anatomical structure of each finger is comprised of four phalanges (distal, middle, proximal, and metacarpal phalange). The simulations were performed using an inverse dynamics technique. The joint angles and the normal contact forces on each finger section reported by previous researchers were used as inputs, while the joint moments of each finger were predicted. The predicted trends of the dependence of the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joint moments on the cylinder diameter agree with those of the contact forces on the fingers observed in the previous experimental study. Our results show that the DIP and PIP joint moments reach their maximums at a cylinder diameter of about 31mm, which is consistent with the trend of the finger contact forces measured in the experiments. The proposed approach will be useful for simulating musculoskeletal loading in the hand for occupational activities, thereby optimizing tool-handle design.

  7. The large terminase DNA packaging motor grips DNA with its ATPase domain for cleavage by the flexible nuclease domain.

    PubMed

    Hilbert, Brendan J; Hayes, Janelle A; Stone, Nicholas P; Xu, Rui-Gang; Kelch, Brian A

    2017-01-12

    Many viruses use a powerful terminase motor to pump their genome inside an empty procapsid shell during virus maturation. The large terminase (TerL) protein contains both enzymatic activities necessary for packaging in such viruses: the adenosine triphosphatase (ATPase) that powers DNA translocation and an endonuclease that cleaves the concatemeric genome at both initiation and completion of genome packaging. However, how TerL binds DNA during translocation and cleavage remains mysterious. Here we investigate DNA binding and cleavage using TerL from the thermophilic phage P74-26. We report the structure of the P74-26 TerL nuclease domain, which allows us to model DNA binding in the nuclease active site. We screened a large panel of TerL variants for defects in binding and DNA cleavage, revealing that the ATPase domain is the primary site for DNA binding, and is required for nuclease activity. The nuclease domain is dispensable for DNA binding but residues lining the active site guide DNA for cleavage. Kinetic analysis of DNA cleavage suggests flexible tethering of the nuclease domains during DNA cleavage. We propose that interactions with the procapsid during DNA translocation conformationally restrict the nuclease domain, inhibiting cleavage; TerL release from the capsid upon completion of packaging unlocks the nuclease domains to cleave DNA.

  8. Competing with the Cartels: How Mexico’s Government Can Reduce Organized Crime’s Economic Grip on its People

    DTIC Science & Technology

    2011-10-28

    company Petroleos Mexicanos ( PEMEX ). The government has finally realized that it cannot rely solely on oil exports to grow the economy, but will have...to diversify.46 In an effort to reform its energy sector, President Calderon convinced the Mexican Congress to allow PEMEX to partner with private

  9. "Coming to grips with the nursing question": the politics of nursing education reform in 1960s America.

    PubMed

    Tobbell, Dominique A

    2014-01-01

    The 1950s and 1960s were decades of change for the American nursing profession. A new generation of nurse educators sought to create greater professional autonomy for the nurse by introducing new models of education that emphasized science-based learning over technical skills and bedside care, and creating new clinical roles for the nurse, based on advanced graduate education. They confronted resistance from an older generation of nurses who feared becoming "second-class citizens" in increasingly academic nursing schools, and from academic health care institutions all too comfortable with the gendered hierarchy on which the traditional model of nursing education and practice was predicated. Using the University of Minnesota and University of California-Los Angeles (UCLA) as case studies, and based on institutional records and more than 40 oral histories with nursing and medical faculty, this article describes the generational conflicts this new cadre of nurse educators confronted within schools of nursing, and the institutional politics they struggled with as they sought to secure greater institutional status for the schools among the universities' other health science units.

  10. Motor Prediction at the Edge of Instability: Alteration of Grip Force Control during Changes in Bimanual Coordination

    ERIC Educational Resources Information Center

    Danion, Frederic; Jirsa, Viktor K.

    2010-01-01

    Predicting the consequences of actions is fundamental for skilled motor behavior. We investigated whether motor prediction is influenced by the fact that some movements are easier to perform and stabilize than others. Twelve subjects performed a bimanual rhythmical task either symmetrically or asymmetrically (the latter being more difficult and…

  11. Tensile Properties of Dyneema SK76 Single Fibers at Multiple Loading Rates Using a Direct Gripping Method

    DTIC Science & Technology

    2014-06-01

    AVAILABILITY STATEMENT Approved for public release; distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Ultra-high- molecular -weight...AZCO, The Netherlands) are frequently used in protective armor, though ultra-high- molecular -weight polyethylene (UHMWPE) fibers such as Dyneema (DSM...The High Strain Rate Response of Ultra High Molecular Weight Polyethylene: From Fibre to Laminate. International Journal of Impact Engineering 2013

  12. Design and Evaluation of a Cable-Driven fMRI-Compatible Haptic Interface to Investigate Precision Grip Control

    PubMed Central

    Vigaru, Bogdan; Sulzer, James; Gassert, Roger

    2016-01-01

    Our hands and fingers are involved in almost all activities of daily living and, as such, have a disproportionately large neural representation. Functional magnetic resonance imaging investigations into the neural control of the hand have revealed great advances, but the harsh MRI environment has proven to be a challenge to devices capable of delivering a large variety of stimuli necessary for well-controlled studies. This paper presents a fMRI-compatible haptic interface to investigate the neural mechanisms underlying precision grasp control. The interface, located at the scanner bore, is controlled remotely through a shielded electromagnetic actuation system positioned at the end of the scanner bed and then through a high stiffness, low inertia cable transmission. We present the system design, taking into account requirements defined by the biomechanics and dynamics of the human hand, as well as the fMRI environment. Performance evaluation revealed a structural stiffness of 3.3 N/mm, renderable forces up to 94 N, and a position control bandwidth of at least 19 Hz. MRI-compatibility tests showed no degradation in the operation of the haptic interface or the image quality. A preliminary fMRI experiment during a pilot study validated the usability of the haptic interface, illustrating the possibilities offered by this device. PMID:26441454

  13. Tablet Keyboard Configuration Affects Performance, Discomfort and Task Difficulty for Thumb Typing in a Two-Handed Grip.

    PubMed

    Trudeau, Matthieu B; Catalano, Paul J; Jindrich, Devin L; Dennerlein, Jack T

    2013-01-01

    When holding a tablet computer with two hands, the touch keyboard configuration imposes postural constraints on the user because of the need to simultaneously hold the device and type with the thumbs. Designers have provided users with several possible keyboard configurations (device orientation, keyboard layout and location). However, potential differences in performance, usability and postures among these configurations have not been explored. We hypothesize that (1) the narrower standard keyboard layout in the portrait orientation leads to lower self-reported discomfort and less reach than the landscape orientation; (2) a split keyboard layout results in better overall outcomes compared to the standard layout; and (3) the conventional bottom keyboard location leads to the best outcomes overall compared to other locations. A repeated measures laboratory experiment of 12 tablet owners measured typing speed, discomfort, task difficulty, and thumb/wrist joint postures using an active marker system during typing tasks for different combinations of device orientation (portrait and landscape), keyboard layout (standard and split), and keyboard location (bottom, middle, top). The narrower standard keyboard with the device in the portrait orientation was associated with less discomfort (least squares mean (and S.E.) 2.9±0.6) than the landscape orientation (4.5±0.7). Additionally, the split keyboard decreased the amount of reaching required by the thumb in the landscape orientation as defined by a reduced range of motion and less MCP extension, which may have led to reduced discomfort (2.7±0.6) compared to the standard layout (4.5±0.7). However, typing speed was greater for the standard layout (127±5 char./min.) compared to the split layout (113±4 char./min.) regardless of device orientation and keyboard location. Usage guidelines and designers can incorporate these findings to optimize keyboard design parameters and form factors that promote user performance and usability for thumb interaction.

  14. Mindfulness-Based Parent Training: Strategies to Lessen the Grip of Automaticity in Families with Disruptive Children

    ERIC Educational Resources Information Center

    Dumas, Jean E.

    2005-01-01

    Disagreements and conflicts in families with disruptive children often reflect rigid patterns of behavior that have become overlearned and automatized with repeated practice. These patterns are mindless: They are performed with little or no awareness and are highly resistant to change. This article introduces a new, mindfulness-based model of…

  15. Getting a Grip on Social Gaze: Control over Others' Gaze Helps Gaze Detection in High-Functioning Autism

    ERIC Educational Resources Information Center

    Dratsch, Thomas; Schwartz, Caroline; Yanev, Kliment; Schilbach, Leonhard; Vogeley, Kai; Bente, Gary

    2013-01-01

    We investigated the influence of control over a social stimulus on the ability to detect direct gaze in high-functioning autism (HFA). In a pilot study, 19 participants with and 19 without HFA were compared on a gaze detection and a gaze setting task. Participants with HFA were less accurate in detecting direct gaze in the detection task, but did…

  16. 'Study of several involuntary functions of the apparatus of movement, gripping, and voice' by Jean-Marc Gaspard Itard (1825).

    PubMed

    Newman, Sara

    2006-09-01

    Itard's 1825 paper, written while he was Chief Physician at the National Institute for Deaf-Mutes in Paris, demonstrates his empiricist approach to medicine. That is, Itard founded his medical practice on sense and experience rather than on surgery and medication. If all knowledge came through the senses, Itard reasoned, those lacking knowledge or social abilities could be improved by appropriate sensory stimulation. This concern with senses and society, along with his different approaches to men and women, his references to contemporary cures and his comparisons between humans and animals, document early nineteenth-century medical and psychological attitudes and treatments. Itard's paper also contains what was later recognized as the first clinical observation of Gilles de la Tourette Syndrome (TS).

  17. Short term microgravity effect on isometric hand grip and precision pinch force with visual and proprioceptive feedback

    NASA Astrophysics Data System (ADS)

    Pastacaldi, P.; Orsini, P.; Bracciaferri, F.; Neri, G.; Porciani, M.; Liuni, L.; Zolesi, V.

    2004-01-01

    Experiments executed on the upper limb are assuming increasing significance in the frame of the Human Physiology in space, for at least two reasons: the upper limb is the principal means of locomotion for the subject living in a space station; furthermore, fatigue can have a significant effect on the hand, for the ordinary work on board, and in particular for the extra-vehicular activities. The degradation of the performances affecting the muscular-skeletal apparatus can be easily recognized on the upper limb, by exerting specific scientific protocols, to be repeated through the permanence of the subject in weightlessness conditions. Another aspect relevant to the effect of microgravity on the upper limb is associated with the alteration of the motor control programs due to the different gravity factor, affecting not only the bio-mechanics of the subject, but in general all his/her psycho-physical conditions, induced by the totally different environment. Specific protocols on the upper limb can facilitate the studies on learning mechanisms for the motor control. The results of such experiments can be transferred to the Earth, useful for treatment of subjects with local traumas or diseases of the Central Nervous System.

  18. Effect of a modified grip angle of a walker on the wrist deviation angle, muscle activation and palmar load during walker-assisted gait in elderly people

    PubMed Central

    Lee, Sang-Yeol; Kim, Seon-Chill; Lee, Young-Ik

    2017-01-01

    [Purpose] The aim of this study was to develop a new handle holder by modifying the inclination of the existing handle holder to reduce load on the wrist joints. [Subjects and Methods] The subjects of this study consisted of 25 elderly people aged 65 years or older accustomed to a walker-assisted gait. Two types of handle holders ((1) standard handle holder (2) inclination handle holder) were applied to all subjects and their wrist joint movement and muscle activity were measured while they conducted 10 cycle walker-assisted gait. [Results] The use of an inclination handle holder during the walker-assisted gait decreased considerably the extensor carpi radialis longus activity and angles of the ulnar deviation and wrist extension. [Conclusion] Improvements in the overall structure of a walker may be a new tool for improving existing walker users but the replacement cost will be expensive. The inclination handle holder presented in this study decreases the burden on the wrist joints of walker users without any overall structural changes in the walker, thereby reducing the occurrence of musculoskeletal diseases of the wrist joint during the walker-assisted gait of elderly people. PMID:28356620

  19. People Getting a Grip on Arthritis II: An Innovative Strategy to Implement Clinical Practice Guidelines for Rheumatoid Arthritis and Osteoarthritis Patients through Facebook

    ERIC Educational Resources Information Center

    Brosseau, Lucie; Wells, George A.; Brooks, Sydney; De Angelis, G.; Bell, Mary; Egan, Mary; Poitras, Stephane; King, Judy; Casimiro, Lynn; Loew, Laurianne; Novikov, Michael

    2014-01-01

    Objective: The purpose of the study is to determine if an updated online evidence-based educational programme delivered through Facebook is effective in improving the knowledge, skills, and self-efficacy of patients with arthritis in relation to evidence-based self-management rehabilitation interventions for osteoarthritis (OA) and rheumatoid…

  20. Coming to grips with a "new" state of consciousness: the study of rapid-eye-movement sleep in the 1960s.

    PubMed

    Morrison, Adrian R

    2013-01-01

    The recognition of rapid-eye-movement sleep (REM) and its association with dreaming in 1953 by Aserinsky and Kleitman opened a new world to explore in the brain. Discussions at two major symposia in the early 1960s reveal that a state with characteristics resembling both wakefulness and sleep was overturning accepted views of the regulation of the two states. Participants grappled with the idea that cortical activation could occur during sleep. They struggled with picking a name that would capture the essence of REM without focusing on just one aspect of the state. Questioning whether REM in cats could be homologous with that of humans suggested an anthropocentric focus on human dreaming as the essence of the state. The need for biochemical studies was evident given that deprivation of REM caused a rebound in the amount of subsequent REM, which indicated that simple synaptic activity could not support this phenomenon.

  1. A First Look at the Structure of the Wave Pouch during the 2009 PREDICT-GRIP Dry Runs over the Atlantic

    DTIC Science & Technology

    2012-04-01

    importance of a Lagrangian recirculation region within a tropical-wave critical layer (the so-called pouch), where persistent deep convection and...emphasizes the importance of a Lagrangian recirculation region within a tropical-wave critical layer (the so-called pouch) where persistent deep convection...for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data and the satellite brightness temperature between 1979 and 2001, Hopsch et al. (2010

  2. EEG-informed fMRI analysis during a hand grip task: estimating the relationship between EEG rhythms and the BOLD signal

    PubMed Central

    Sclocco, Roberta; Tana, Maria G.; Visani, Elisa; Gilioli, Isabella; Panzica, Ferruccio; Franceschetti, Silvana; Cerutti, Sergio; Bianchi, Anna M.

    2014-01-01

    In the last decade, an increasing interest has arisen in investigating the relationship between the electrophysiological and hemodynamic measurements of brain activity, such as EEG and (BOLD) fMRI. In particular, changes in BOLD have been shown to be associated with changes in the spectral profile of neural activity, rather than with absolute power. Concurrently, recent findings showed that different EEG rhythms are independently related to changes in the BOLD signal: therefore, it would be also important to distinguish between the contributions of the different EEG rhythms to BOLD fluctuations when modeling the relationship between the two signals. Here we propose a method to perform EEG-informed fMRI analysis where the changes in the spectral profile are modeled, and, at the same time, the distinction between rhythms is preserved. We compared our model with two other frequency-dependent regressors modeling using simultaneous EEG-fMRI data from healthy subjects performing a motor task. Our results showed that the proposed method better captures the correlations between BOLD signal and EEG rhythms modulations, identifying task-related, well localized activated volumes. Furthermore, we showed that including among the regressors also EEG rhythms not primarily involved in the task enhances the performance of the analysis, even when only correlations with BOLD signal and specific EEG rhythms are explored. PMID:24744720

  3. Do We Need Another Hero? Year 8 Get to Grips with the Heroic Myth of the Defence of Rorke's Drift in 1879

    ERIC Educational Resources Information Center

    Murray, Mike

    2013-01-01

    Mike Murray shares a lesson sequence in which his students examined changing interpretations of the Battle of Rorke's Drift in 1879. Building on earlier work on teaching interpretations across an extended chronological period and the work of Wheeley et al on Rorke's Drift in particular, Murray develops new emphases, fresh ways in to the puzzle and…

  4. Crystal Structure of the Conserved Amino Terminus of the Extracellular Domain of Matrix Protein 2 of Influenza A Virus Gripped by an Antibody.

    PubMed

    Cho, Ki Joon; Schepens, Bert; Moonens, Kristof; Deng, Lei; Fiers, Walter; Remaut, Han; Saelens, Xavier

    2015-10-14

    We report the crystal structure of the M2 ectodomain (M2e) in complex with a monoclonal antibody that binds the amino terminus of M2. M2e extends into the antibody binding site to form an N-terminal β-turn near the bottom of the paratope. This M2e folding differs significantly from that of M2e in complex with an antibody that binds another part of M2e. This suggests that M2e can adopt at least two conformations that can elicit protective antibodies.

  5. Plasmid curing and the loss of grip--the 65-kb replicon of Phaeobacter inhibens DSM 17395 is required for biofilm formation, motility and the colonization of marine algae.

    PubMed

    Frank, Oliver; Michael, Victoria; Päuker, Orsola; Boedeker, Christian; Jogler, Christian; Rohde, Manfred; Petersen, Jörn

    2015-03-01

    Surface colonization is characteristic for a broad range of marine roseobacters and many strains have been isolated from biofilms, microbial mats and dinoflagellates. Phaeobacter inhibens DSM 17395, one of the best-studied representatives of the Roseobacter group, is an effective colonizer of marine surfaces, but the genetic basis of this trait is unknown. Based on the composition of its 65-kb RepA-I type plasmid that contains more than 20 genes for polysaccharide metabolism, including a rhamnose operon, which is required for O-antigen formation in Escherichia coli, it was hypothesized that this replicon was essential for surface attachment. Accordingly, a holistic approach was taken and the functional role of this extrachromosomal element in P. inhibens was investigated. Plasmid curing was performed with the homologous RepA-I replication system of Dinoroseobacter shibae DSM 16493(T). The Δ65-kb mutant completely lost its stickiness and could neither attach to artificial (glass, polystyrene) nor to natural surfaces (algae) and, consequently, its ability to form biofilms was impaired. Surprisingly, the mutant also lost the capacity for flagellar swimming motility required for surface colonization and the dispersal of biofilms. The data clearly showed that the 65-kb replicon of P. inhibens DSM 17395 was a genuine biofilm plasmid-mediating surface attachment. Homologous replicons are widely distributed among Rhodobacterales thus indicating the general importance of extrachromosomal elements for biofilm formation.

  6. When are Overcomplete Representations Identifiable? Uniqueness of Tensor Decompositions Under Expansion Constraints

    DTIC Science & Technology

    2013-06-16

    ArxXiv preprint, abs/1206.5882, 2012. [38] Nikolaos Fountoulakis and Konstantinos Panagiotou. Sharp load thresholds for cuckoo hashing. Random Struct... cuckoo hash tables. Random Struct. Algorithms, 41(3):334–364, 2012. [40] Martin Dietzfelbinger, Andreas Goerdt, Michael Mitzenmacher, Andrea...Montanari, Rasmus Pagh, and Michael Rink. Tight thresholds for cuckoo hashing via xorsat. Arxiv preprint arXiv:0912.0287, Dec. 2010. [41] V. Chvátal. The

  7. Folding tools for flat conductor cable harnesses

    NASA Technical Reports Server (NTRS)

    Loggins, R.

    1971-01-01

    Vise grip pliers have detachable metal gripping plates which are changed to accommodate cables from 1 to 3 in. wide and to form any desired fold angle. A second tool squeezes cable along crease to complete the fold.

  8. Split-Rail, Rolling-Friction Robotic Gripper With Tool Drive

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    1992-01-01

    Robotic gripper includes split-rail drive assembly that moves two gripping fingers toward or away from each other. Gripping fingers equipped with rollers mating with recesses and seating ramps on specially designed object. Similar in design and operation, to those described in "Rolling-Friction Robotic Gripper" (GSC-13261). Present gripper includes rotary tool operating on mechanism in gripped object.

  9. Task-dependent modulation of excitatory and inhibitory functions within the human primary motor cortex.

    PubMed

    Tinazzi, Michele; Farina, Simona; Tamburin, Stefano; Facchini, Stefano; Fiaschi, Antonio; Restivo, Domenico; Berardelli, Alfredo

    2003-05-01

    We evaluated motor evoked potentials (MEPs) and duration of the cortical silent period (CSP) from the right first dorsal interosseous (FDI) muscle to transcranial magnetic stimulation (TMS) of the left motor cortex in ten healthy subjects performing different manual tasks. They abducted the index finger alone, pressed a strain gauge with the thumb and index finger in a pincer grip, and squeezed a 4-cm brass cylinder with all digits in a power grip. The level of FDI EMG activity across tasks was kept constant by providing subjects with acoustic-visual feedback of their muscle activity. The TMS elicited larger amplitude FDI MEPs during pincer and power grip than during the index finger abduction task, and larger amplitude MEPs during pincer gripping than during power gripping. The CSP was shorter during pincer and power grip than during the index finger abduction task and shorter during power gripping than during pincer gripping. These results suggest excitatory and inhibitory task-dependent changes in the motor cortex. Complex manual tasks (pincer and power gripping) elicit greater motor cortical excitation than a simple task (index finger abduction) presumably because they activate multiple synergistic muscles thus facilitating corticomotoneurons. The finger abduction task probably yielded greater motor cortical inhibition than the pincer and power tasks because muscles uninvolved in the task activated the cortical inhibitory circuit. Increased cortical excitatory and inhibitory functions during precision tasks (pincer gripping) probably explain why MEPs have larger amplitudes and CSPs have longer durations during pincer gripping than during power gripping.

  10. Glutamate Receptor Interacting Protein 1 Mediates Platelet Adhesion and Thrombus Formation

    PubMed Central

    Modjeski, Kristina L.; Ture, Sara K.; Field, David J.; Cameron, Scott J.; Morrell, Craig N.

    2016-01-01

    Thrombosis-associated pathologies, such as myocardial infarction and stroke, are major causes of morbidity and mortality worldwide. Because platelets are necessary for hemostasis and thrombosis, platelet directed therapies must balance inhibiting platelet function with bleeding risk. Glutamate receptor interacting protein 1 (GRIP1) is a large scaffolding protein that localizes and organizes interacting proteins in other cells, such as neurons. We have investigated the role of GRIP1 in platelet function to determine its role as a molecular scaffold in thrombus formation. Platelet-specific GRIP1-/- mice were used to determine the role of GRIP1 in platelets. GRIP1-/- mice had normal platelet counts, but a prolonged bleeding time and delayed thrombus formation in a FeCl3-induced vessel injury model. In vitro stimulation of WT and GRIP1-/- platelets with multiple agonists showed no difference in platelet activation. However, in vivo platelet rolling velocity after endothelial stimulation was significantly greater in GRIP1-/- platelets compared to WT platelets, indicating a potential platelet adhesion defect. Mass spectrometry analysis of GRIP1 platelet immunoprecipitation revealed enrichment of GRIP1 binding to GPIb-IX complex proteins. Western blots confirmed the mass spectrometry findings that GRIP1 interacts with GPIbα, GPIbβ, and 14-3-3. Additionally, in resting GRIP1-/- platelets, GPIbα and 14-3-3 have increased interaction compared to WT platelets. GRIP1 interactions with the GPIb-IX binding complex are necessary for normal platelet adhesion to a stimulated endothelium. PMID:27631377

  11. Evaluation of four steering wheels to determine driver hand placement in a static environment.

    PubMed

    Mossey, Mary E; Xi, Yubin; McConomy, Shayne K; Brooks, Johnell O; Rosopa, Patrick J; Venhovens, Paul J

    2014-07-01

    While much research exists on occupant packaging both proprietary and in the literature, more detailed research regarding user preferences for subjective ratings of steering wheel designs is sparse in published literature. This study aimed to explore the driver interactions with production steering wheels in four vehicles by using anthropometric data, driver hand placement, and driver grip design preferences for Generation-Y and Baby Boomers. In this study, participants selected their preferred grip diameter, responded to a series of questions about the steering wheel grip as they sat in four vehicles, and rank ordered their preferred grip design. Thirty-two male participants (16 Baby Boomers between ages 47 and 65 and 16 Generation-Y between ages 18 and 29) participated in the study. Drivers demonstrated different gripping behavior between vehicles and between groups. Recommendations for future work in steering wheel grip design and naturalistic driver hand positioning are discussed.

  12. A Race for Martyrdom: The Islamic Revolutionary Guards Corps (IRGC)

    DTIC Science & Technology

    1982-12-01

    a completely revolutionary and decisive g manner." The clergy obtained an even tighter grip on Iran when the Assembly of Experts put the...tightened their grip around the city, many regular army officers and noncommissioned officers fled Ahwaz. Ayatollah Montazeri addressed this and...demoralizing effect on the Iranian army, tightened the Iraqi grip on Ahwaz, in- creased the fundamentalist pressure on Bani-Sadr, and given

  13. A Framework for Recognizing Grasps

    DTIC Science & Technology

    1991-11-01

    form. He partitions the functions of the hand into cylinder grasp, ball grasp, ring grasp, pincer grasp and plier grasp. McBride [33] took a different...being strictly prismatic and strictly spherical). In these cases, determination of 1. He actually referred to them as precision grips and power grips ...and Wright, PK., "Modeling Manufacturing Grips and Correlations with the Design of Robotic Hands," Pro,. IEEE Int’l Conf. on Robotics and

  14. A Strategic Plan for the Persian Gulf Region: Options for Deterring and/or Defeating an Emerging Threat

    DTIC Science & Technology

    1992-12-01

    an independent Kurdistan would impinge on their territorial integrity. Additionally Saddam’s grip on power shows signs of weakening. There have been...Abramowitz stresses the need for a rational plan in dealing with this region’s uncertain future: ... any U.S. administration will have to come to grips with...opposition groups. Although Saddam has been able to maintain a grip on political power, it has not been without costs. Military leaders have been purged

  15. Fatigue Response of Pretensioned Concrete Beams

    DTIC Science & Technology

    2003-08-01

    capacity of that bridge. This bridge, known as the Chandler Creek Bridge (Hagenberger 2003), which crosses Chandler Creek on the northbound frontage road of...drilling a long slender hole and risking drill bit wobble . The details of the grips used and gripping procedure are available in Appendix B. 2.4.4...faces. With the threaded grip, a hole must be drilled using a long drill bit. There is no way to ensure that the drill bit does not wobble , which can

  16. Shooting Performance as a Function of Shooters’ Anthropometrics, Weapon Design Attributes, Firing Position, Range, and Sex

    DTIC Science & Technology

    2014-10-01

    length, and rightward horizontal neck rotation may predict shooting performance under time pressure while firing from either a reflexive firing...Shoulder-elbow length • Forearm-hand length 7 • Hand circumference • Hand length 6.1.3 Ratios Relative to Grip Reach The arm and hand length...parameter values were used to determine these ratios. • Shoulder-elbow length to grip reach • Forearm-hand length to grip reach • Hand size ( circumference

  17. Hand-Strength Meter

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Elliot, Joe

    1987-01-01

    Special grip-strength meter designed for accurate, reproducible measurement of hand rehabilitation. Four strain gauges connected in Wheatstone bridge to measure deflection caused by gripping hand. Compressive force exerted by hand transmitted to measuring beams. Beams therefore deflected or strained, and mechanical strain sensed by strain gauges and converted into electrical signal. After amplification and conditioning, signal displayed on LED as measure of gripping strength of hand.

  18. 3 degree of freedom hand controller

    NASA Technical Reports Server (NTRS)

    Menahem, Israel (Inventor)

    1992-01-01

    A hand controller which includes a hand grip having therein a gimble mechanism for allowing rotatory motion about three axes which intersect in the interior of the hand grip and from which motion transmitting members allow the motions about the three axes to be transmitted to remote pick off devices and also along which force feedback signals may be fedback to the gimble structure to provide the correct feel for the grip.

  19. Contributions and co-ordination of individual fingers in multiple finger prehension.

    PubMed

    Kinoshita, H; Kawai, S; Ikuta, K

    1995-06-01

    The contributions and co-ordination of external finger grip forces were examined during a lifting task with a precision grip using multiple fingers. The subjects (n = 10) lifted a force transducer-equipped grip apparatus. Grip force from each of the five fingers was continuously measured under different object weight (200 g, 400 g and 800 g) and surface structure (plastic and sandpaper) conditions. The effect of five-, four-, and three-finger grip modes was also examined. It was found that variation of object weight or surface friction resulted in change of the total grip force magnitude; the largest change in finger force, was that for the index finger, followed by the middle, ring, and little fingers. Percentage contribution of static grip force to the total grip force for the index, middle, ring, and little fingers was 42.0%, 27.4%, 17.6% and 12.9%, respectively. These values were fairly constant for all object weight conditions, as well as for all surface friction conditions, suggesting that all individual finger force adjustments for light loads less than 800 g are controlled comprehensively simply by using a single common scaling value. A higher surface friction provided faster lifting initiation and required lesser grip force exertion, indicating advantageous effect of a non-slippery surface over a slippery surface. The results indicate that nearly 40% force reduction can be obtained when a non-slippery surface is used. Variation in grip mode changed the total grip force, i.e., the fewer the number of fingers, the greater the total grip force. The percent value of static grip force for the index, middle, and ring fingers in the four-finger grip mode was 42.7%, 32.5%, and 24.7%, respectively, and that for the index and middle fingers in the three-finger grip mode was 43.0% and 56.9%, respectively. Therefore, the grip mode was found to influence the force contributions of the middle and ring fingers, but not of the index finger.

  20. Fingertip moisture is optimally modulated during object manipulation.

    PubMed

    André, T; Lefèvre, P; Thonnard, J-L

    2010-01-01

    Coordination between the normal force exerted by fingers on a held object and the tangential constraints at the fingertips helps to successfully manipulate objects. It is well established that the minimal grip force required to prevent an object from slipping strongly depends on the frictional properties at the finger-object interface. Moreover, interindividual variation in the modulation of grip force suggests that the moisture level of the skin could influence grip force strategy. In the present study we asked subjects to perform a horizontal point-to-point task holding an object with a precision grip. The object was equipped with a moisture sensor. We found large inter- and intraindividual moisture level variations. There was a strong correlation between grip force exerted and moisture level at the fingertips. Indeed, the grip force was minimal when the fingertip moisture was optimal with respect to friction. Furthermore, fingertip moisture tended toward this optimal level at which grip force is minimal. In conclusion, we showed a modulation of the grip force with moisture level and hypothesized novel mechanisms of moisture regulation that tend to stabilize the moisture level toward the value that minimizes grip force.

  1. A clarification of Pouydebat et al., 2008, evolution of grasping among anthropoids.

    PubMed

    Marzke, M W; Pouydebat, E; Laurin, M; Gorce, P; Bels, V

    2009-12-01

    Several statements by Pouydebat et al. (2008) do not adequately represent views of authors cited, in part because they reflect confusion in the literature about terminology regarding precision gripping. We address these problems, by tracing definitions of precision grips through the literature on manipulative behaviour and identifying the grip that is central to the Pouydebat et al. (2008) study. This allows us to offer a clarification of the statements by Pouydebat et al. (2008) regarding the sequence of appearance of human grip capabilities and possible morphological correlates to these capabilities in extant species.

  2. Development of the crone seedlings handling system using 3D-sensor and force control gripper

    NASA Astrophysics Data System (ADS)

    Hojo, Hirotaka; Takarada, Hiroshi; Hiroyasu, Takahisa; Hata, Seiji

    2005-12-01

    The crone seedlings have unstable form and it is hard to handle. In order to transplant crone seedlings automatically, the functions of 3D-shape recognition and force control of grippers are indispensable. We have introduced the new handling technology which combines the 3D-mesurement using the relative stereo method and gripping method by gripping stroke control for high elasticity forceps structure. In this gripping method, the gripping force is controlled according to the shoot diameter which is measured by 3d-mesurment of relative stereo method. The experimental crone seedlings transplant system using the new handling technique has been shown.

  3. Bimanual Force Coordination in Children with Spastic Unilateral Cerebral Palsy

    ERIC Educational Resources Information Center

    Smits-Engelsman, B. C. M.; Klingels, K.; Feys, H.

    2011-01-01

    In this study bimanual grip-force coordination was quantified using a novel "Gripper" system that records grip forces produced while holding a lower and upper unit, in combination with the lift force necessary to separate these units. Children with unilateral cerebral palsy (CP) (aged 5-14 years, n = 12) were compared to age matched typically…

  4. The Influence of Temperature and Composition on the Activation Energy for Creep in Binary Aluminum Lithium Alloys

    DTIC Science & Technology

    1990-12-01

    thermocouples. Special self aligning grips, manufactured with Inconel Alloy 625, were designed to hold the creep specimens (Figure 4). These grips were made...manually ground to 600 grit and polished with 1 Am diamond paste. The samples were subsequently electropolished and etched using a 20 modified Barker’s

  5. Construction of a Hyper Redundant Robotic Tentacle Manipulator

    DTIC Science & Technology

    2012-06-01

    are parallel- gripping pincers (5) and three-finger grippers (6), which manipulate objects with a closing-style grasp. The grasping force is...orthogonal to the finger length, and gripping depends on the contact friction and normal force of the gasp to hold an object. Objects are gasped under the

  6. The Long War: Building the Balance Between Today’s Necessities and Tomorrow’s Need

    DTIC Science & Technology

    2009-04-01

    APPROACH TO CHANGE ...................................................63 TWO PRONGED PINCER APPROACH TO CHANGE...unthinkable. Lacking the capacity to come to grips with the enemy, the war would inevitably be a drawn-out contest, a long war. Ike, the general...ally with few countries falling in the middle. The communist scare that gripped the United States, combined with the country’s collective ignorance

  7. 46 CFR 56.30-25 - Flared, flareless, and compression fittings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... pipe by such means as ferrules, flared ends, swaging, elastic strain preload, crimping, bite-type devices, and shape memory alloys. Fittings to which this section applies must be designed, constructed...) Flareless fittings must be of a design in which the gripping member or sleeve must grip or bite into...

  8. 46 CFR 56.30-25 - Flared, flareless, and compression fittings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... pipe by such means as ferrules, flared ends, swaging, elastic strain preload, crimping, bite-type devices, and shape memory alloys. Fittings to which this section applies must be designed, constructed...) Flareless fittings must be of a design in which the gripping member or sleeve must grip or bite into...

  9. Response to Eva Alerby and Cecilia Perm, "Learning Music: Embodied Experience in the Life-World"

    ERIC Educational Resources Information Center

    Fung, C. Victor

    2005-01-01

    At the onset of the essay by Alerby and Perm, musicality is described as emotional or cognitive phenomena. In this response, Fung questions what role a psychomotor phenomenon plays in musicality. Alerby and Perm describe "motor knowledge" in the context of Merleau-Ponty's "maximum grip." Does this mean that "motor knowledge" or "maximum grip" in…

  10. Lifting device for nuclear power plants

    SciTech Connect

    Krieger, F.

    1984-07-17

    A lifting device for lifting and transporting nuclear fuel elements. This device comprises a mast-like support on the lower end of which automatically operated and locked gripping pawls are provided. The support has a considerable height and may be referred to as lifting mast. The gripping pawls and their operating mechanism are referred to as gripping-head. The gripping-head and the lifting mast are telescopically movable relative to each other. To this end guide rods and compression springs are interposed between the lower end of the lifting mast and the gripping-head. The gripping-head comprises two concentric annular members which are relatively movable or rotatable about their common geometrical axis. One of the annular members supports the gripping pawls are T-shaped. One of their transverse ends is adapted to engage the fuel rods, and the other of their transverse ends is adapted to engage curved grooves in the other annular member. The rotary motion of one annular member relative to the other gripping pawls. In their limit positions the two annular members are blocked by a safety lever engaging slits or slots.

  11. Prosthetic Hand For Holding Rods, Tools, And Handles

    NASA Technical Reports Server (NTRS)

    Belcher, Jewell G., Jr.; Vest, Thomas W.

    1995-01-01

    Prosthetic hand with quick-grip/quick-release lever broadens range of specialized functions available to lower-arm amputee by providing improved capabilities for gripping rods, tools, handles, and like. Includes two stationary lower fingers opposed by one pivoting upper finger. Lever operates in conjunction with attached bracket.

  12. 77 FR 44218 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... 51-2.4. Regulatory Flexibility Act Certification I certify that the following action will not have a..., Aluminum Scoop, Industrial Grade, 51'' Fiberglass Handle, Cushioned Grip NSN: 5120-00-NIB-0022--Shovel..., Grain, ABS Scoop, Industrial Grade, 51'' Fiberglass Handle, Cushioned Grip NSN:...

  13. Militarism and Foreign Conflict Behavior: A Quantitative Study Revisited.

    DTIC Science & Technology

    1982-05-20

    to arms,’ but, rather, the populace is answering a more basic call of fthree hots and a cot.0 One wonders if the recent successes the United States...and GRIP Fer Capita@ 19?8* XMIuary Expedture. as % of GRIP Kiddie *Size of circle Is 13 * hu Proportionate to else of popiulation* 10 0 Pact 9 8 7 hUt A

  14. Jar-opening challenges. Part 2: estimating the force-generating capacity of thumb muscles in healthy young adults during jar-opening tasks.

    PubMed

    Kuo, L C; Chang, J H; Lin, C F; Hsu, H Y; Ho, K Y; Su, F C

    2009-07-01

    This study discusses the force-generating capacity of thumb muscles during jar-opening tasks using two grip patterns: the power grip and the precision grip. This study develops a three-dimensional biomechanical model of the thumb to predict muscle forces in jar-opening activities based on external forces measured by a custom-designed jar device. Ten healthy subjects participated in the study. Each participant turned a jar lid of 66 mm diameter counterclockwise with maximal effort and preferred speed using both grip patterns. The average normal and tangential forces applied by the thumb to the jar lid show that the normal force is the primary contributive force for opening a jar. This normal force is approximately three times the tangential force. Muscular force-generating capacity measurements show that the major active muscles during a jar-opening activity for both grips include the flexor pollicis longus, flexor pollicis brevis, abductor pollicis brevis, adductor pollicis, and opponens pollicis. The total muscle force ratios for the precision grip and power grip with respect to externally applied forces are 5.6 and 4.7 respectively. These ratios indicate that the power grip pattern produces less muscle force per unit of external applied load. The technique proposed in this study provides a proper apparatus and model for measuring three-dimensional loads and estimating the force-generating capacity of each muscle and tendon of the thumb during jar-opening tasks.

  15. General Processes, Rather than "Goals," Explain Imitation Errors

    ERIC Educational Resources Information Center

    Bird, Geoffrey; Brindley, Rachel; Leighton, Jane; Heyes, Cecilia

    2007-01-01

    The goal-directed theory of imitation (GOADI) states that copying of action outcomes (e.g., turning a light switch) takes priority over imitation of the means by which those outcomes are achieved (e.g., choice of effector or grip). The object [fewer than] effector [fewer than] grip error pattern in the pen-and-cups task provides strong support for…

  16. A Developmental Approach to Graduate Education Review: A New Take on a Traditional Process

    ERIC Educational Resources Information Center

    Hakkola, Leah; King, Jean A.

    2016-01-01

    In this article we describe the Graduate Review and Improvement Process (GRIP), an innovative evaluation process that makes student input central, now beginning its fifth year of implementation at the University of Minnesota. We begin by contrasting GRIP with traditional graduate program review, and we then explain the conceptual underpinnings of…

  17. Novel Robotic Tools for Piping Inspection and Repair, Phase 1

    DTIC Science & Technology

    2014-02-13

    11 Basic automated motion using software ... mockup horizontally and vertically. Gripping force testing Pulling in an axial direction the gripper assembly achieved 36.33lbs of gripping force...bags being partially inflated (Figure 11). Figure 11 - Gripper sleds Basic automated motion using software The robot successfully ran on auto

  18. Real time 3D visualization of ultrasonic data using a standard PC.

    PubMed

    Nikolov, Svetoslav Ivanov; Pablo Gómez Gonzaléz, Juan; Arendt Jensen, Jørgen

    2003-08-01

    This paper describes a flexible, software-based scan converter capable of rendering 3D volumetric data in real time on a standard PC. The display system is used in the remotely accessible and software-configurable multichannel ultrasound sampling system (RASMUS system) developed at the Center for Fast Ultrasound Imaging. The display system is split into two modules: data transfer and display. These two modules are independent and communicate using shared memory and a predefined set of functions. It is, thus, possible to use the display program with a different data-transfer module which is tailored to another source of data (scanner, database, etc.). The data-transfer module of the RASMUS system is based on a digital signal processor from Analog Devices--ADSP 21060. The beamformer is connected to a PC via the link channels of the ADSP. A direct memory access channel transfers the data from the ADSP to a memory buffer. The display module, which is based on OpenGL, uses this memory buffer as a texture map that is passed to the graphics board. The scan conversion, image interpolation, and logarithmic compression are performed by the graphics board, thus reducing the load on the main processor to a minimum. The scan conversion is done by mapping the ultrasonic data to polygons. The format of the image is determined only by the coordinates of the polygons allowing for any kind of geometry to be displayed on the screen. Data from color flow mapping is added by alpha-blending. The 3D data are displayed either as cross-sectional planes, or as a fully rendered 3D volume displayed as a pyramid. All sides of the pyramid can be changed to reveal B-mode or C-mode scans, and the pyramid can be rotated in all directions in real time.

  19. An in vitro investigation of transverse flow estimation

    NASA Astrophysics Data System (ADS)

    Udesen, Jesper; Jensen, Jorgen A.

    2004-04-01

    Conventional ultrasound scanners are restricted to display the blood velocity component in the ultrasound beam direction. By introducing a laterally oscillating field, signals are created from which the transverse velocity component can be estimated. This paper presents velocity and volume flow estimates obtained from flow phantom and in-vivo measurements at 90° relative to the ultrasound beam axis. The flow phantom experiment setup consists of a SMI140 flow phantom connected to a CompuFlow 1000 programmable flow pump, which generates a flow similarly to that in the femoral artery. A B-K medical 8804 linear array transducer with 128 elements and a center frequency of 7 MHz is emitting 8 cycle ultrasound pulses with a pulse repetition frequency of 7 kHz in a direction perpendicular to the flow direction in the phantom. The transducer is connected to the experimental ultrasound scanner RASMUS, and 1.4 seconds of data is acquired. Using 2 parallel receive beamformers a transverse oscillation is introduced with an oscillation period 1.2 mm. The velocity estimation is performed using an extended autocorrelation algorithm. The volume flow can be estimated with a relative standard deviation of 13.0% and a relative mean bias of 3.4%. The in-vivo experiment is performed on the common carotid artery of a healthy 25 year old male. The same transducer and setup is used as in the flow phantom experiment, and the data is acquired using the RASMUS scanner. The peak velocity of the carotid flow is estimated to 1.2 m/s and the volume flow to 290 ml/min. This is within normal physiological range.

  20. Integration of a computerized two-finger gripper for robot workstation safety

    NASA Technical Reports Server (NTRS)

    Sneckenberger, John E.; Yoshikata, Kazuki

    1988-01-01

    A microprocessor-based controller has been developed that continuously monitors and adjusts the gripping force applied by a special two-finger gripper. This computerized force sensing gripper system enables the endeffector gripping action to be independently detected and corrected. The gripping force applied to a manipulated object is real-time monitored for problem situations, situations which can occur during both planned and errant robot arm manipulation. When unspecified force conditions occur at the gripper, the gripping force controller initiates specific reactions to cause dynamic corrections to the continuously variable gripping action. The force controller for this intelligent gripper has been interfaced to the controller of an industrial robot. The gripper and robot controllers communicate to accomplish the successful completion of normal gripper operations as well as unexpected hazardous situations. An example of an unexpected gripping condition would be the sudden deformation of the object being manipulated by the robot. The capabilities of the interfaced gripper-robot system to apply workstation safety measures (e.g., stop the robot) when these unexpected gripping effects occur have been assessed.

  1. Systematic Influence of Perceived Grasp Shape on Speech Production

    PubMed Central

    Vainio, Lari; Rantala, Aleksi; Tiainen, Mikko; Tiippana, Kaisa; Komeilipoor, Naeem; Vainio, Martti

    2017-01-01

    Previous research has shown that precision and power grip performance is consistently influenced by simultaneous articulation. For example, power grip responses are performed relatively fast with the open-back vowel [a], whereas precision grip responses are performed relatively fast with the close-front vowel [i]. In the present study, the participants were presented with a picture of a hand shaped to the precision or power grip. They were required to pronounce speech sounds according to the front/above perspective of the hand. The results showed that not only the grip performance is affected by simultaneously pronouncing the speech sound but also the production of speech sound can be affected by viewing an image of a grip. The precision grip stimulus triggered relatively rapid production of the front-close vowel [i]. In contrast, the effect related to the power grip stimulus was mostly linked to the vertical dimension of the pronounced vowel since this stimulus triggered relatively rapid production of the back-open vowel [a] and back-mid-open vowel [o] while production of the back-close vowel [u] was not influenced by it. The fact that production of the dorsal consonant [k] or coronal consonant [t] were not influenced by these stimuli suggests that the effect was not associated with a relative front-back tongue shape of the articulation in the absence of changes in any vertical articulatory components. These findings provide evidence for an intimate interaction between certain articulatory gestures and grip types, suggesting that an overlapping visuomotor network operates for planning articulatory gestures and grasp actions. PMID:28103278

  2. Conceptual knowledge for understanding other's actions is organized primarily around action goals.

    PubMed

    van Elk, M; van Schie, H T; Bekkering, H

    2008-07-01

    Semantic knowledge about objects entails both knowing how to grasp an object (grip-related knowledge) and what to do with an object (goal-related knowledge). Considerable evidence suggests a hierarchical organization in which specific hand-grips in action execution are most often selected to accomplish a remote action goal. The present study aimed to investigate whether a comparable hierarchical organization of semantic knowledge applies to the recognition of other's object-directed actions as well. Correctness of either the Grip (hand grip applied to the object) or the Goal (end-location at which an object was directed) were manipulated independently in two experiments. In Experiment 1, subjects were required to attend selectively to either the correctness of the grip or the goal of the observed action. Subjects were faster when attending to the goal of the action and a strong interference of goal-violations was observed when subjects attended to the grip of the action. Importantly, observation of irrelevant goal- or grip-related violations interfered with making decisions about the correctness of the relevant dimension only when the relevant dimension was correct. In contrast, in Experiment 2, when subjects attended to an action-irrelevant stimulus dimension (i.e. orientation of the object), no interference of goal- or grip-related violations was found, ruling out the possibility that interference-effects result from perceptual differences between stimuli. These findings suggest that understanding the correctness of an action selectively recruits specialized, but interacting networks, processing the correctness of goal- and grip-specific information during action observation.

  3. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    DOEpatents

    Young, J.N.

    1958-04-22

    An electromagnetic apparatus for moving a rod-like member in small steps in either direction is described. The invention has particular application in the reactor field where the reactor control rods must be moved only a small distance and where the use of mechanical couplings is impractical due to the high- pressure seals required. A neutron-absorbing rod is mounted in a housing with gripping uaits that engage the rod, and coils for magnetizing the gripping units to make them grip, shift, and release the rod are located outside the housing.

  4. Compliant Gripper for a Robotic Manipulator

    NASA Technical Reports Server (NTRS)

    Cipra, Raymond; Das, Hari

    2003-01-01

    A figure depicts a prototype of a robotic-manipulator gripping device that includes two passive compliant fingers, suitable for picking up and manipulating objects that have irregular shapes and/or that are, themselves, compliant. The main advantage offered by this device over other robotic-manipulator gripping devices is simplicity: Because of the compliance of the fingers, force-feedback control of the fingers is not necessary for gripping objects of a variety of sizes, shapes, textures, and degrees of compliance. Examples of objects that can be manipulated include small stones, articles of clothing, and parts of plants.

  5. The War Against Trucks Aerial Interdiction in Southern Laos 1968-1972

    DTIC Science & Technology

    2005-01-01

    roadwatch teams proved too great a nuisance to the enemy, he strengthened security and denied access to the roads that he considered vital. As the grip on...enemy. Most of the families that had agreed to leave hoped to return and harvest their crops if the royal government maintained its grip on the area, and...Vietnamese could not 138 The War against Trucks maintain a grip on easternmost Cambodia, nor could Lon Nol contain the Khmer Rouge, even though U.S. air

  6. Fastening apparatus having shape memory alloy actuator

    NASA Technical Reports Server (NTRS)

    Mckinnis, Darin N. (Inventor)

    1992-01-01

    A releasable fastening apparatus is presented. The device includes a connecting member and a housing. The housing supports a gripping mechanism that is adapted to engage the connecting member. A triggering member is movable within the housing between a first position in which it constrains the gripping mechanism in locked engagement with the connecting member, and a second position in which the gripping mechanism is disengaged from the connecting member. A shaped memory alloy actuator is employed for translating the triggering member from its first to its second position. The actuator is designed to expand longitudinally when transitioned from a martensitic to an austenitic state.

  7. Concentric wrench for blind access opening in a turbine

    DOEpatents

    Laurer, Kurt Neal; Drlik, Gary Joseph; Gibler, Edward Eugene

    2001-01-01

    The concentric wrench includes an outer tube having flats at one end and a gripping surface at an opposite end. An inner tube has interior flats at one end and a gripping surface at its opposite end. With the inner and outer tubes disposed about a pressure transmitting conduit, the tubes may be inserted into a blind access opening in the outer turbine casing to engage the flats of the tubes against hex nuts of an internal fitting. By relatively rotating the tubes using the externally exposed gripping surfaces, the threaded connection between the parts of the fitting bearing the respective hex nuts can be tightened or loosened.

  8. Airborne Wind Profiling With the Data Acquisition and Processing System for a Pulsed 2-Micron Coherent Doppler Lidar System

    NASA Technical Reports Server (NTRS)

    Beyon, Jeffrey Y.; Koch, Grady J.; Kavaya, Michael J.

    2012-01-01

    A pulsed 2-micron coherent Doppler lidar system at NASA Langley Research Center in Virginia flew on the NASA's DC-8 aircraft during the NASA Genesis and Rapid Intensification Processes (GRIP) during the summer of 2010. The participation was part of the project Doppler Aerosol Wind Lidar (DAWN) Air. Selected results of airborne wind profiling are presented and compared with the dropsonde data for verification purposes. Panoramic presentations of different wind parameters over a nominal observation time span are also presented for selected GRIP data sets. The realtime data acquisition and analysis software that was employed during the GRIP campaign is introduced with its unique features.

  9. A practical microgripper by fine alignment, eutectic bonding and SMA actuation

    SciTech Connect

    Lee, A.P.; Ciarlo, D.R.; Krulevitch, P.A.

    1995-04-21

    A silicon microgripper with a large gripping force, a relatively rigid structural body, and flexibility in functional design is presented. The actuation is generated by Ni-Ti-Cu shape memory alloy (SMA) films and the stress induced can deflect each side of the microgripper up to 55 {mu}m for a total gripping motion of 110 {mu}m. When fully open, the force exerted by the film corresponds to a 40 mN gripping force on the tip of the gripper.

  10. Design and implementation of a multiaxial loading capability during heating on an engineering neutron diffractometer

    DOE PAGES

    Benafan, O.; Padula, S. A.; Skorpenske, H. D.; ...

    2014-10-02

    Here we discuss a gripping capability that was designed, implemented, and tested for in situ neutron diffraction measurements during multiaxial loading and heating on the VULCAN engineering materials diffractometer at the spallation neutron source at Oak Ridge National Laboratory.

  11. Science needs reason to be trusted

    NASA Astrophysics Data System (ADS)

    Hossenfelder, Sabine

    2017-04-01

    That we now live in the grip of post-factualism would seem naturally repellent to most physicists. But in championing theory without demanding empirical evidence, we're guilty of ignoring the facts ourselves.

  12. Writing forces associated with four pencil grasp patterns in grade 4 children.

    PubMed

    Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

    2013-01-01

    OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern.

  13. The effect of a long-term exercise programme on the rheumatoid hand.

    PubMed

    Brighton, S W; Lubbe, J E; van der Merwe, C A

    1993-05-01

    Forty-four female patients with sero-positive active RA participated in a 48-month trial to assess the effect of simple hand exercises. Twenty-two patients in the test group were given a daily exercise regime of six exercises. The control group were not given any exercises. At the end of 48 months there was a statistically significant improvement in grip strength (P < 0.0001) and pincer grip strength (P < 0.0005) in the test group. There was a significant deterioration in the control group (P < 0.0000). A simple exercise programme is beneficial for the rheumatoid hand as far as grip and pincer grip strength are concerned.

  14. Fastener starter tool

    NASA Technical Reports Server (NTRS)

    Chandler, Faith T. (Inventor); Valentino, William D. (Inventor); Garton, Harry L. (Inventor); Arnett, Michael C. (Inventor)

    2003-01-01

    A fastener starter tool includes a number of spring retention fingers for retaining a small part, or combination of parts. The tool has an inner housing, which holds the spring retention fingers, a hand grip, and an outer housing configured to slide over the inner housing and the spring retention fingers toward and away from the hand grip, exposing and opening, or respectively, covering and closing, the spring retention fingers. By sliding the outer housing toward (away from) the hand grip, a part can be released from (retained by) the tool. The tool may include replaceable inserts, for retaining parts, such as screws, and configured to limit the torque applied to the part, to prevent cross threading. The inner housing has means to transfer torque from the hand grip to the insert. The tool may include replaceable bits, the inner housing having means for transferring torque to the replaceable bit.

  15. Tavaborole Topical

    MedlinePlus

    ... insert it in the bottle. Squeeze the dropper bulb and then loosen your grip to fill the ... dropper over your affected toenail and squeeze the bulb slowly to release enough medication to cover your ...

  16. ABP: a novel AMPA receptor binding protein.

    PubMed

    Srivastava, S; Ziff, E B

    1999-04-30

    We review the cloning of a novel AMPA receptor binding protein (ABP) that interacts with GluR2/3 and is homologous to GRIP. ABP is enriched in the PSD with GluR2 and is localized to the PSD by EM. ABP binds GluR2 via the C-terminal VXI motif through a Class I PDZ interaction. ABP and GRIP can also homo- and heteromultimerize. Thus, ABP and GRIP may be involved in AMPA receptor regulation and localization, by linking it to other cytoskeletal or signaling molecules. We suggest that the ABP/GRIP and PSD-95 families form distinct scaffolds that anchor, respectively, AMPA and NMDA receptors. We are currently investigating proteins that bind ABP and that may regulate the AMPA receptor.

  17. Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.

  18. Rare Muscular Dystrophies: Congenital, Distal, Emery-Dreifuss and Oculopharyngeal Muscular Dystrophies

    MedlinePlus

    ... the respiratory muscles are affected, while limb muscle strength is less affected. Intellectual function is normal. Problems ... therapist can recommend devices that may improve grip strength or help support your arms for using a ...

  19. Carpal Tunnel Syndrome

    MedlinePlus

    ... might feel tingling during the day. Decreased grip strength may make it difficult to form a fist, ... base of the hand should be examined for strength and signs of atrophy. Routine laboratory tests and ...

  20. Brainstem White Matter Predicts Individual Differences in Manual Motor Difficulties and Symptom Severity in Autism

    PubMed Central

    Travers, Brittany G.; Bigler, Erin D.; Tromp, Do P. M.; Adluru, Nagesh; Destiche, Dan; Samsin, Danica; Froehlich, Alyson; Prigge, Molly D. B.; Duffield, Tyler; Lange, Nicholas; Alexander, Andrew L.; Lainhart, Janet E.

    2015-01-01

    Mounting evidence suggests that poorer motor skills may be related to more severe autism symptoms. This study investigated if atypical white matter microstructure in the brain mediated the relationship between motor skills and ASD symptom severity. Sixty-seven males with ASD and 42 males with typical development (5-33 years old) completed a diffusion tensor imaging scan and measures of grip strength, finger tapping, and autism symptom severity. Within the ASD group, weaker grip strength predicted more severe autism symptoms. Fractional anisotropy of the brainstem's corticospinal tract predicted both grip strength and autism symptom severity and mediated the relationship between the two. These findings suggest that brainstem white matter may contribute to autism symptoms and grip strength in ASD. PMID:26001365