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Sample records for finger thermoregulatory model

  1. Thermoregulatory control of finger blood flow

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  2. Thermoregulatory modeling for cold stress.

    PubMed

    Xu, Xiaojiang; Tikuisis, Peter

    2014-07-01

    Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview. PMID:24944030

  3. Transient thermoregulatory model with graphics output

    NASA Technical Reports Server (NTRS)

    Grounds, D. J.

    1974-01-01

    A user's guide is presented for the transient version of the thermoregulatory model. The model is designed to simulate the transient response of the human thermoregulatory system to thermal inputs. The model consists of 41 compartments over which the terms of the heat balance are computed. The control mechanisms which are identified are sweating, vaso-constriction and vasodilation.

  4. A Self-Organising Model of Thermoregulatory Huddling

    PubMed Central

    Glancy, Jonathan; Groß, Roderich; Stone, James V.; Wilson, Stuart P.

    2015-01-01

    Endotherms such as rats and mice huddle together to keep warm. The huddle is considered to be an example of a self-organising system, because complex properties of the collective group behaviour are thought to emerge spontaneously through simple interactions between individuals. Groups of rodent pups display two such emergent properties. First, huddling undergoes a ‘phase transition’, such that pups start to aggregate rapidly as the temperature of the environment falls below a critical temperature. Second, the huddle maintains a constant ‘pup flow’, where cooler pups at the periphery continually displace warmer pups at the centre. We set out to test whether these complex group behaviours can emerge spontaneously from local interactions between individuals. We designed a model using a minimal set of assumptions about how individual pups interact, by simply turning towards heat sources, and show in computer simulations that the model reproduces the first emergent property—the phase transition. However, this minimal model tends to produce an unnatural behaviour where several smaller aggregates emerge rather than one large huddle. We found that an extension of the minimal model to include heat exchange between pups allows the group to maintain one large huddle but eradicates the phase transition, whereas inclusion of an additional homeostatic term recovers the phase transition for large huddles. As an unanticipated consequence, the extended model also naturally gave rise to the second observed emergent property—a continuous pup flow. The model therefore serves as a minimal description of huddling as a self-organising system, and as an existence proof that group-level huddling dynamics emerge spontaneously through simple interactions between individuals. We derive a specific testable prediction: Increasing the capacity of the individual to generate or conserve heat will increase the range of ambient temperatures over which adaptive thermoregulatory huddling

  5. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

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

  6. THREE-DIMENSIONAL FINITE-DIFFERENCE THERMOREGULATORY MODEL OF A SQUIRREL MONKEY

    EPA Science Inventory

    A three-dimensional thermoregulatory model of a squirrel monkey, whose shape is approximated by 742 rectangular blocks of varying sizes, has been developed. The inhomogeneous model has four layers: a core, a composite layer of muscle and fat, skin, and fur. The model simulates th...

  7. Testing the Fitness Consequences of the Thermoregulatory and Parental Care Models for the Origin of Endothermy

    PubMed Central

    Clavijo-Baque, Sabrina; Bozinovic, Francisco

    2012-01-01

    The origin of endothermy is a puzzling phenomenon in the evolution of vertebrates. To address this issue several explicative models have been proposed. The main models proposed for the origin of endothermy are the aerobic capacity, the thermoregulatory and the parental care models. Our main proposal is that to compare the alternative models, a critical aspect is to determine how strongly natural selection was influenced by body temperature, and basal and maximum metabolic rates during the evolution of endothermy. We evaluate these relationships in the context of three main hypotheses aimed at explaining the evolution of endothermy, namely the parental care hypothesis and two hypotheses related to the thermoregulatory model (thermogenic capacity and higher body temperature models). We used data on basal and maximum metabolic rates and body temperature from 17 rodent populations, and used intrinsic population growth rate (Rmax) as a global proxy of fitness. We found greater support for the thermogenic capacity model of the thermoregulatory model. In other words, greater thermogenic capacity is associated with increased fitness in rodent populations. To our knowledge, this is the first test of the fitness consequences of the thermoregulatory and parental care models for the origin of endothermy. PMID:22606328

  8. User's instructions for the 41-node thermoregulatory model (steady state version)

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1974-01-01

    A user's guide for the steady-state thermoregulatory model is presented. The model was modified to provide conversational interaction on a remote terminal, greater flexibility for parameter estimation, increased efficiency of convergence, greater choice of output variable and more realistic equations for respiratory and skin diffusion water losses.

  9. Fingering in Stochastic Growth Models

    PubMed Central

    Aristotelous, Andreas C.; Durrett, Richard

    2015-01-01

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

  10. FINITE-DIFFERENCE ELECTROMAGNETIC DEPOSITION/THERMOREGULATORY MODEL: COMPARISON BETWEEN THEORY AND MEASUREMENTS (JOURNAL VERSION)

    EPA Science Inventory

    The rate of the electromagnetic energy deposition and the resultant thermoregulatory response of a block model of a squirrel monkey exposed to plane-wave fields at 350 MHz were calculated using a finite-difference procedure. Noninvasive temperature measurements in live squirrel m...

  11. An improved thermoregulatory model for cooling garment applications with transient metabolic rates

    NASA Astrophysics Data System (ADS)

    Westin, Johan K.

    Current state-of-the-art thermoregulatory models do not predict body temperatures with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments for optimizing cooling efficiency, for making LCGs as portable and practical as possible, for alleviating the individual from manual cooling control, and for improving thermal comfort and cognitive performance. In this study, we adopt the Fiala thermoregulatory model, which has previously demonstrated state-of-the-art predictive abilities in air environments, for use in LCG environments. We validate the numerical formulation with analytical solutions to the bioheat equation, and find our model to be accurate and stable with a variety of different grid configurations. We then compare the thermoregulatory model's tissue temperature predictions with experimental data where individuals, equipped with an LCG, exercise according to a 700 W rectangular type activity schedule. The root mean square (RMS) deviation between the model response and the mean experimental group response is 0.16°C for the rectal temperature and 0.70°C for the mean skin temperature, which is within state-of-the-art variations. However, with a mean absolute body heat storage error 3¯ BHS of 9.7 W˙h, the model fails to satisfy the +/-6.5 W˙h accuracy that is required for the automatic LCG cooling control development. In order to improve model predictions, we modify the blood flow dynamics of the thermoregulatory model. Instead of using step responses to changing requirements, we introduce exponential responses to the muscle blood flow and the vasoconstriction command. We find that such modifications have an insignificant effect on temperature predictions. However, a new vasoconstriction dependency, i.e. the rate of change of hypothalamus temperature weighted by the

  12. Coupling of three-dimensional field and human thermoregulatory models in a crowded enclosure

    SciTech Connect

    Xue, H.; Kang, Z.J.; Bong, T.Y.

    1999-11-12

    Health, comfort, and energy conservation are important factors to consider in the design of a building and its HVAC systems. Advanced tools are required to evaluate parameters regarding airflow, temperature, and humidity ratio in buildings, with the end results being better indoor air quality and thermal environment as well as increased confidence in the performance of buildings. A numerical model coupling the three-dimensional field and human thermoregulatory models is proposed and developed. A high-Re {kappa}-{epsilon} turbulence model is used for the field simulation. A modified 25-mode model of human thermoregulation is adopted to predict human thermal response in physiological parameters, such as body temperature and body heat loss. Distributions of air velocity, temperature, and moisture content are demonstrated in a crowded enclosure with mechanical ventilation under two ventilation rates. The results are analyzed and discussed. The coupling model is useful in assisting and verifying ventilation and air-conditioning system designs.

  13. Use of Thermoregulatory Models to Enhance Space Shuttle and Space Station operations and Review of Human Thermoregulatory Control

    NASA Technical Reports Server (NTRS)

    Pisacane, V. L.; Kuznetz, L. H.; Logan, J. S.; Clark, J. B.; Wissler, E. H.

    2007-01-01

    Thermoregulation in the space environment is critical for survival, especially in off- nominal operations. In such cases, mathematical models of thermoregulation are frequently employed to evaluate safety-of-flight issues in various human mission scenarious. In this study, the 225-node Wissler model and the 41-Node Metabolic Man model are employed to evaluate the effects of such a scenario. Metabolic loads on astronauts wearing the advanced crew escape suit (ACES) and liquid cooled ventilation garment (LCVG) are imposed on astronauts exposed to elevated cabin temperatures resulting from a systems failure. The study indicates that the performance of the ACES/LCVG cooling system is marginal. Increases in workload and or cabin temperature above nominal will increase rectal temperature, stored heat load, heart rate, and sweating, which could lead to deficits in the performance of cognitive and motor tasks. This is of concern as the ACES/LCVG is employed during Shuttle decent when the likelihood of a safe landing may be compromised. The study indicates that the most effective mitigation strategy would be to decrease the LCVG inlet temperature.

  14. Ethnic differences in thermoregulatory responses during resting, passive and active heating: application of Werner's adaptation model.

    PubMed

    Lee, Joo-Young; Wakabayashi, Hitoshi; Wijayanto, Titis; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

    2011-12-01

    For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives' homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder's law of initial value and Werner's process and controller adaptation model. PMID:21437607

  15. Thermoregulatory, behavioral, and metabolic responses to heatstroke in a conscious mouse model.

    PubMed

    Leon, Lisa R; Gordon, Christopher J; Helwig, Bryan G; Rufolo, Dennis M; Blaha, Michael D

    2010-07-01

    The typical core temperature (T(c)) profile displayed during heatstroke (HS) recovery consists of initial hypothermia followed by delayed hyperthermia. Anecdotal observations led to the conclusion that these T(c) responses represent thermoregulatory dysfunction as a result of brain damage. We hypothesized that these T(c) responses are mediated by a change in the temperature setpoint. T(c) (+/- 0.1 degrees C; radiotelemetry) of male C57BL/6J mice was monitored while they were housed in a temperature gradient with ambient temperature (T(a)) range of 20-39 degrees C to monitor behaviorally selected T(a) (T(s)) or an indirect calorimeter (T(a) = 25 degrees C) to monitor metabolism (V(O(2))) and calculate respiratory exchange ratio (RER). Responses to mild and severe HS (thermal area 249.6 +/- 18.9 vs. 299.4 +/- 19.3 degrees C.min, respectively) were examined through 48 h of recovery. An initial hypothermia following mild HS was associated with warm T(s) (approximately 32 degrees C), approximately 35% V(O(2)) decrease, and RER approximately 0.71 that indicated reliance on fatty acid oxidation. After 24 h, mild HS mice developed hyperthermia associated with warm T(s) (approximately 32 degrees C), approximately 20% V(O(2)) increase, and RER approximately 0.85. Severe HS mice appeared poikilothermic-like in the temperature gradient with T(c) similar to T(s) (approximately 20 degrees C), and these mice failed to recover from hypothermia and develop delayed hyperthermia. Cellular damage (hematoxylin and eosin staining) was undetectable in the hypothalamus or other brain regions in severe HS mice. Overall, decreases and increases in T(c) were associated with behavioral and autonomic thermoeffectors that suggest HS elicits anapyrexia and fever, respectively. Taken together, T(c) responses of mild and severe HS mice suggest a need for reinterpretation of the mechanisms of thermoregulatory control during recovery. PMID:20427722

  16. Applications of real-time thermoregulatory models to occupational heat stress: validation with military and civilian field studies.

    PubMed

    Yokota, Miyo; Berglund, Larry G; Santee, William R; Buller, Mark J; Karis, Anthony J; Roberts, Warren S; Cuddy, John S; Ruby, Brent C; Hoyt, Reed W

    2012-07-01

    A real-time thermoregulatory model using noninvasive measurements as inputs was developed for predicting physiological responses of individuals working long hours. The purpose of the model is to reduce heat-related injuries and illness by predicting the physiological effects of thermal stress on individuals while working. The model was originally validated mainly by using data from controlled laboratory studies. This study expands the validation of the model with field data from 26 test volunteers, including US Marines, Australian soldiers, and US wildland fire fighters (WLFF). These data encompass a range of environmental conditions (air temperature: 19-30° C; relative humidity: 25-63%) and clothing (i.e., battle dress uniform, chemical-biological protective garment, WLFF protective gear), while performing diverse activities (e.g., marksmanship, marching, extinguishing fires, and digging). The predicted core temperatures (Tc), calculated using environmental, anthropometric, clothing, and heart rate measures collected in the field as model inputs, were compared with subjects' Tc collected with ingested telemetry temperature pills. Root mean standard deviation (RMSD) values, used for goodness of fit comparisons, indicated that overall, the model predictions were in close agreement with the measured values (grand mean of RMSD: 0.15-0.38° C). Although the field data showed more individual variability in the physiological data relative to more controlled laboratory studies, this study showed that the performance of the model was adequate. PMID:22614223

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

    PubMed

    Fok, Kim Seng; Chou, Siaw Meng

    2010-03-01

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

  18. Thermoregulatory models of safety-for-flight issues for space operations

    NASA Astrophysics Data System (ADS)

    Pisacane, V. L.; Kuznetz, L. H.; Logan, J. S.; Clark, J. B.; Wissler, E. H.

    2006-10-01

    This study investigates the use of a mathematical model for thermoregulation as a tool in safety-of-flight issues and proposed solutions for mission operations of the Space Shuttle and the International Space Station. Specifically, this study assesses the effects of elevated cabin temperature and metabolic loads on astronauts wearing the Advanced Crew Escape Suit (ACES) and the Liquid Cooled Ventilation Garment (LCVG). The 225-node Wissler model is validated by comparison with two ground-based human subject tests, firefighters, and surrogate astronauts under anomalous conditions that show good agreement. Subsequent simulations indicate that the performance of the ACES/LCVG is marginal. Increases in either workload or cabin temperature from the nominal will increase rectal temperature, stored heat load, heart rate, and sweating leading to possible deficits in the ability of the astronauts to perform cognitive and motor tasks that could affect the safety of the mission, especially the safe landing of the Shuttle. Specific relationships are given between cabin temperature and metabolic rate that define the threshold for decreased manual dexterity and loss of tracking skills. Model results indicate that the most effective mitigation strategy would be to decrease the LCVG inlet temperature. Methods of accomplishing this are also proposed.

  19. Finger interaction during maximal radial and ulnar deviation efforts: experimental data and linear neural network modeling

    PubMed Central

    Pataky, Todd C.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2010-01-01

    The purpose of this study was to characterize finger interactions during radial/ulnar deviation, including interactions with flexion movements. Subjects performed single-finger and multi-finger maximal voluntary contraction (MVC), and maximal forces and various indices of interaction among the fingers were quantified. MVCs in radial/ulnar deviation were 50–80% as strong as in flexion. Along with the ‘master’ fingers (i.e., those explicitly instructed to produce force), substantial force production was also observed in ‘slave’ fingers (i.e., those not explicitly instructed to produce force), a phenomenon termed: force ‘enslaving’. In addition, a drop in MVC during multi-finger tasks as compared to single finger tasks (force ‘deficit’) was also observed. A previously unreported phenomenon that we term: ‘preferred direction enslaving’ was also apparent; both master and slave fingers produced force in the instructed direction with a non-zero perpendicular component. Due to the architectural separation of the involved muscles, preferred direction enslaving provides strong evidence that enslaving results from neural rather than biomechanical factors. A final new phenomenon: ‘negative deficit’, or force ‘facilitation’ was observed in 46.4% of the trials in 21 out of 23 subjects during multi-finger lateral efforts and was further demonstrative of extensive interconnection among neurons serving hand muscles. The data were modeled with high accuracy (~4% mean square error) using a linear neural network with motor ‘commands’ as inputs and finger forces as outputs. The proposed network, equivalent to linear regression, can be used to determine the extent to which finger forces are influenced by peripheral constraints during functional prehensile activities. PMID:17334750

  20. Structural model of ubiquitin transfer onto an artificial RING finger as an E3 ligase

    NASA Astrophysics Data System (ADS)

    Miyamoto, Kazuhide

    2014-10-01

    The artificial WSTF PHD_EL5 RING finger was designed via ``α-helical region substitution'', and its structural model for the attachment of activated ubiquitin has been demonstrated. Chemical modifications of Cys residues, the circular dichroism spectra, and substrate-independent ubiquitination assays illustrated that the WSTF PHD_EL5 RING finger has E3 activity, and it is ubiquitinated via Lys14. Homology modeling calculations revealed that the WSTF PHD_EL5 RING finger possesses a classical RING fold for specific E2-E3 binding. The docking poses of the WSTF PHD_EL5 RING finger with the UbcH5b-ubiquitin conjugate provided insight into its functional E2 interaction and development of ubiquitination at the atomic level. The structural model of the artificial WSTF PHD_EL5 RING finger proposed by the present work is useful and may help to extend the strategy of α-helical region substitution.

  1. Modeling of contact mechanics and friction limit surfaces for soft fingers in robotics, with experimental results

    SciTech Connect

    Xydas, N.; Kao, I.

    1999-09-01

    A new theory in contact mechanics for modeling of soft fingers is proposed to define the relationship between the normal force and the radius of contact for soft fingers by considering general soft-finger materials, including linearly and nonlinearly elastic materials. The results show that the radius of contact is proportional to the normal force raised to the power of {gamma}, which ranges from 0 to 1/3. This new theory subsumes the Hertzian contact model for linear elastic materials, where {gamma} = 1/3. Experiments are conducted to validate the theory using artificial soft fingers made of various materials such as rubber and silicone. Results for human fingers are also compared. This theory provides a basis for numerically constructing friction limit surfaces. The numerical friction limit surface can be approximated by an ellipse, with the major and minor axes as the maximum friction force and the maximum moment with respect to the normal axis of contact, respectively. Combining the results of the contact-mechanics model with the contact-pressure distribution, the normalized friction limit surface can be derived for anthropomorphic soft fingers. The results of the contact-mechanics model and the pressure distribution for soft fingers facilitate the construction of numerical friction limit surfaces, and will enable us to analyze and simulate contact behaviors of grasping and manipulation in robotics.

  2. Mathematical model and solution for fingering phenomenon in double phase flow through homogeneous porous media.

    PubMed

    Mistry, Piyush R; Pradhan, Vikas H; Desai, Khyati R

    2013-01-01

    The present paper analytically discusses the phenomenon of fingering in double phase flow through homogenous porous media by using variational iteration method. Fingering phenomenon is a physical phenomenon which occurs when a fluid contained in a porous medium is displaced by another of lesser viscosity which frequently occurred in problems of petroleum technology. In the current investigation a mathematical model is presented for the fingering phenomenon under certain simplified assumptions. An approximate analytical solution of the governing nonlinear partial differential equation is obtained using variational iteration method with the use of Mathematica software. PMID:24348161

  3. Evidence evaluation in fingerprint comparison and automated fingerprint identification systems--Modeling between finger variability.

    PubMed

    Egli Anthonioz, N M; Champod, C

    2014-02-01

    In the context of the investigation of the use of automated fingerprint identification systems (AFIS) for the evaluation of fingerprint evidence, the current study presents investigations into the variability of scores from an AFIS system when fingermarks from a known donor are compared to fingerprints that are not from the same source. The ultimate goal is to propose a model, based on likelihood ratios, which allows the evaluation of mark-to-print comparisons. In particular, this model, through its use of AFIS technology, benefits from the possibility of using a large amount of data, as well as from an already built-in proximity measure, the AFIS score. More precisely, the numerator of the LR is obtained from scores issued from comparisons between impressions from the same source and showing the same minutia configuration. The denominator of the LR is obtained by extracting scores from comparisons of the questioned mark with a database of non-matching sources. This paper focuses solely on the assignment of the denominator of the LR. We refer to it by the generic term of between-finger variability. The issues addressed in this paper in relation to between-finger variability are the required sample size, the influence of the finger number and general pattern, as well as that of the number of minutiae included and their configuration on a given finger. Results show that reliable estimation of between-finger variability is feasible with 10,000 scores. These scores should come from the appropriate finger number/general pattern combination as defined by the mark. Furthermore, strategies of obtaining between-finger variability when these elements cannot be conclusively seen on the mark (and its position with respect to other marks for finger number) have been presented. These results immediately allow case-by-case estimation of the between-finger variability in an operational setting. PMID:24447455

  4. Potential application of FoldX force field based protein modeling in zinc finger nucleases design.

    PubMed

    He, ZuYong; Mei, Gui; Zhao, ChunPeng; Chen, YaoSheng

    2011-05-01

    Engineered sequence-specific zinc finger nucleases (ZFNs) make the highly efficient modification of eukaryotic genomes possible. However, most current strategies for developing zinc finger nucleases with customized sequence specificities require the construction of numerous tandem arrays of zinc finger proteins (ZFPs), and subsequent largescale in vitro validation of their DNA binding affinities and specificities via bacterial selection. The labor and expertise required in this complex process limits the broad adoption of ZFN technology. An effective computational assisted design strategy will lower the complexity of the production of a pair of functional ZFNs. Here we used the FoldX force field to build 3D models of 420 ZFP-DNA complexes based on zinc finger arrays developed by the Zinc Finger Consortium using OPEN (oligomerized pool engineering). Using nonlinear and linear regression analysis, we found that the calculated protein-DNA binding energy in a modeled ZFP-DNA complex strongly correlates to the failure rate of the zinc finger array to show significant ZFN activity in human cells. In our models, less than 5% of the three-finger arrays with calculated protein-DNA binding energies lower than -13.132 kcal mol(-1) fail to form active ZFNs in human cells. By contrast, for arrays with calculated protein-DNA binding energies higher than -5 kcal mol(-1), as many as 40% lacked ZFN activity in human cells. Therefore, we suggest that the FoldX force field can be useful in reducing the failure rate and increasing efficiency in the design of ZFNs. PMID:21455692

  5. A new analytical compact model for two-dimensional finger photodiodes

    NASA Astrophysics Data System (ADS)

    Naeve, T.; Hohenbild, M.; Seegebrecht, P.

    2008-02-01

    A new physically based circuit simulation model for finger photodiodes has been proposed. The approach is based on the solution of transport and continuity equation for generated carriers within the two-dimensional structure. As an example we present results of a diode consisting of N+-fingers located in a P-well on top of a N-type buried layer integrated in a P-type silicon substrate (N+/PW/NBL/Psub finger photodiode). The model is capable to predict the sensitivity of the diode in a wide spectral range very accurately. The structure under consideration was fabricated in an industrial 0.6 μm BiCMOS process. The good agreement of simulated sensitivity data with results of measurements and numerical simulations demonstrate the high quality of our model.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  8. A Phase-field Model of Wetting in Porous Media -- Origin of Gravity Fingering During Infiltration

    NASA Astrophysics Data System (ADS)

    Juanes, Ruben; Cueto-Felgueroso, Luis

    2009-11-01

    We present a new continuum mathematical model of wetting into dry soil. The inspiration for the new model is the flow of thin films (like water down a plane), which also displays fingering instability. The key idea is very simple: the macroscopic equations must reflect the presence of a macroscopic interface---the wetting front. We then cast the model in the rigorous framework of phase-field models and nonlocal thermodynamics. The new model is appealing. It is a simple extension of the traditional model---Richards' equation---with a new term (a fourth-order derivative in space) but without any new parameters. It reproduces the two key features of unsaturated flow: a nonmonotonic saturation profile, and gravity fingering. It explains why, when, and how, fingers form. It shows excellent quantitative agreement with experiments in terms of tip saturation, tip velocity and finger width. The most attractive aspect is, however, that the new model offers a starting point for fundamentally new formulations of multiphase flow in porous media.

  9. An improved predictive recognition model for Cys2-His2 zinc finger proteins

    PubMed Central

    Gupta, Ankit; Christensen, Ryan G.; Bell, Heather A.; Goodwin, Mathew; Patel, Ronak Y.; Pandey, Manishi; Enuameh, Metewo Selase; Rayla, Amy L.; Zhu, Cong; Thibodeau-Beganny, Stacey; Brodsky, Michael H.; Joung, J. Keith; Wolfe, Scot A.; Stormo, Gary D.

    2014-01-01

    Cys2-His2 zinc finger proteins (ZFPs) are the largest family of transcription factors in higher metazoans. They also represent the most diverse family with regards to the composition of their recognition sequences. Although there are a number of ZFPs with characterized DNA-binding preferences, the specificity of the vast majority of ZFPs is unknown and cannot be directly inferred by homology due to the diversity of recognition residues present within individual fingers. Given the large number of unique zinc fingers and assemblies present across eukaryotes, a comprehensive predictive recognition model that could accurately estimate the DNA-binding specificity of any ZFP based on its amino acid sequence would have great utility. Toward this goal, we have used the DNA-binding specificities of 678 two-finger modules from both natural and artificial sources to construct a random forest-based predictive model for ZFP recognition. We find that our recognition model outperforms previously described determinant-based recognition models for ZFPs, and can successfully estimate the specificity of naturally occurring ZFPs with previously defined specificities. PMID:24523353

  10. Microwaves modify thermoregulatory behavior in squirrel monkey

    SciTech Connect

    Adair, E.R.; Adams, B.W.

    1980-01-01

    Squirrel monkeys (Saimiri sciureus) trained to regulate environmental temperature (Ta) behaviorally were exposed in the far field of a horn antenna to ten-minute periods of 2,450 MHz CW microwaves. Incident power density ranged from 1 to 22 mW/cm2. The corresponding specific absorption rate (SAR), derived from temperature increments in saline-filled styrofoam models, ranged from 0.15 to 3.25 W/kg. Controls included exposure to infrared radiation equivalent incident energy and no radiation exposure. Normal thermo-regulatory behavior produces tight control over environmental and body temperatures; most monkeys select a Ta of 34-36 degrees C. Ten-minute exposures to 2,450 MHz CW microwaves at an incident power density of 6-8 mW/cm2 stimulated all animals to select a lower Ta. This threshold energy represents a whole-body SAR of 1.1 W/kg, about 20% of the resting metabolic rate of the monkey. Thermoregulatory behavior was highly efficient, and skin and rectal temperatures remained stable, even at 22 mW/cm2 where the preferred Ta was lowered by as much as 4 degrees C. No comparable reduction in selected Ta below control levels occurred during exposure to infrared radiation of equal incident power density.

  11. Modeling gravity-driven fingering in rough-walled fractures using modified percolation theory

    SciTech Connect

    Glass, R.J.

    1992-12-31

    Pore scale invasion percolation theory is modified for imbibition of.wetting fluids into fractures. The effects of gravity, local aperture field geometry, and local in-plane air/water interfacial curvatureare included in the calculation of aperture filling potential which controls wetted structure growth within the fracture. The inclusion of gravity yields fingers oriented in the direction of the gravitational gradient. These fingers widen and tend to meander and branch more as the gravitational gradient decreases. In-plane interfacial curvature also greatly affects the wetted structure in both horizontal and nonhorizontal fractures causing the formation of macroscopic wetting fronts. The modified percolation model is used to simulate imbibition into an analogue rough-walled fracture where both fingering and horizontal imbibition experiments were previously conducted. Comparison of numerical and experimental results showed reasonably good agreement. This process oriented physical and numerical modeling is-a necessary step toward including gravity-driven fingering in models of flow and transport through unsaturated, fractured rock.

  12. A model for multi-finger HBTs including current gain collapse effects

    NASA Astrophysics Data System (ADS)

    Garlapati, Akhil; Prasad, Sheila; Vempada, Pradeep; Munshi, Kambiz

    2003-11-01

    A common-emitter equivalent circuit model which represents both the self-heating and the current collapse as feedback from the collector current to the base-emitter voltage is developed for multi-finger InGaAs/GaAs HBTs. The modified Ebers-Moll model is verified by comparing the simulated and measured results. Good agreement is also achieved for the scattering parameters and I- V characteristics confirming the validity of the model for high frequency applications.

  13. Quantum chemical modelling of reactivity and selectivity of 1,2-dithiolanes towards retroviral and cellular zinc fingers

    NASA Astrophysics Data System (ADS)

    Topol, Igor A.; Nemukhin, Alexander V.; Burt, Stanley K.

    Interactions of 1,2-dithiolane species with zinc-containing sites, which mimic the zinc finger domains of retroviral and the cellular zinc finger proteins, have been investigated by quantum chemistry tools. According to the calculations, the immediate domains of zinc binding sites in the cellular and retroviral zinc fingers interact differently with such agents of the disulphide family. Thus, when approaching the model cellular-type domains, the molecules of 1,2-dithiolanes experience considerable potential barriers along the reaction path. However, these species react practically barrier-less with the model retroviral-type domains at the correlated DFT level. The results of the quantum chemical modelling provide firm support to the selectivity of 1,2-dithiolanes towards retroviral and cellular zinc fingers. This can be of great practical importance for the design of therapeutics that accomplish functional inactivation of the zinc fingers of the human immunodeficiency virus (HIV-1) retroviral type nucleocapsid protein NCp7.

  14. Fingering in Confined Elastic Layers

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  15. Extension of the dielectric breakdown model for simulation of viscous fingering at finite viscosity ratios

    NASA Astrophysics Data System (ADS)

    Doorwar, Shashvat; Mohanty, Kishore K.

    2014-07-01

    Immiscible displacement of viscous oil by water in a petroleum reservoir is often hydrodynamically unstable. Due to similarities between the physics of dielectric breakdown and immiscible flow in porous media, we extend the existing dielectric breakdown model to simulate viscous fingering patterns for a wide range of viscosity ratios (μr). At low values of power-law index η, the system behaves like a stable Eden growth model and as the value of η is increased to unity, diffusion limited aggregation-like fractals appear. This model is compared with our two-dimensional (2D) experiments to develop a correlation between the viscosity ratio and the power index, i.e., η = 10-5μr0.8775. The 2D and three-dimensional (3D) simulation data appear scalable. The fingering pattern in 3D simulations at finite viscosity ratios appear qualitatively similar to the few experimental results published in the literature.

  16. Extension of the dielectric breakdown model for simulation of viscous fingering at finite viscosity ratios.

    PubMed

    Doorwar, Shashvat; Mohanty, Kishore K

    2014-07-01

    Immiscible displacement of viscous oil by water in a petroleum reservoir is often hydrodynamically unstable. Due to similarities between the physics of dielectric breakdown and immiscible flow in porous media, we extend the existing dielectric breakdown model to simulate viscous fingering patterns for a wide range of viscosity ratios (μ(r)). At low values of power-law index η, the system behaves like a stable Eden growth model and as the value of η is increased to unity, diffusion limited aggregation-like fractals appear. This model is compared with our two-dimensional (2D) experiments to develop a correlation between the viscosity ratio and the power index, i.e., η = 10(-5)μ(r)(0.8775). The 2D and three-dimensional (3D) simulation data appear scalable. The fingering pattern in 3D simulations at finite viscosity ratios appear qualitatively similar to the few experimental results published in the literature. PMID:25122390

  17. Modifications to the steady-state 41-node thermoregulatory model including validation of the respiratory and diffusional water loss equations

    NASA Technical Reports Server (NTRS)

    1974-01-01

    After the simplified version of the 41-Node Stolwijk Metabolic Man Model was implemented on the Sigma 3 and UNIVAC 1110 computers in batch mode, it became desirable to make certain revisions. First, the availability of time-sharing terminals makes it possible to provide the capability and flexibility of conversational interaction between user and model. Secondly, recent physiological studies show the need to revise certain parameter values contained in the model. Thirdly, it was desired to make quantitative and accurate predictions of evaporative water loss for humans in an orbiting space station. The result of the first phase of this effort are reported.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  19. Development of a finite element model of a finger pad for biomechanics of human tactile sensations.

    PubMed

    Vodlak, Teja; Vidrih, Zlatko; Fetih, Dusan; Peric, Djordje; Rodic, Tomaz

    2015-08-01

    The aim of ongoing research is to develop a multi-scale multi-physics computational framework for modelling of human touch in order to provide understanding of fundamental biophysical mechanisms responsible for tactile sensation. The paper presents the development of a macro-scale global finite element model of the finger pad and calibration of applied material models against experimental results using inverse method. The developed macro model serves as a basis for down-scaling to micro finite element models of mechanoreceptors and further implementations and applications as a virtual tool in scientific or industrial applications related to neuroscience, haptics, prosthetics, virtual touch and packaging. PMID:26736410

  20. Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode.

    PubMed

    Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

    2014-09-01

    Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the 'modular' body mapping sportswear was designed and subsequently assessed on a 'Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations. PMID:24357489

  1. Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode

    NASA Astrophysics Data System (ADS)

    Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

    2014-09-01

    Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the `modular' body mapping sportswear was designed and subsequently assessed on a `Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

  2. Mean-field diffusion-limited aggregation: a "density" model for viscous fingering phenomena.

    PubMed

    Bogoyavlenskiy, V A

    2001-12-01

    We explore a universal "density" formalism to describe nonequilibrium growth processes, specifically, the immiscible viscous fingering in Hele-Shaw cells (usually referred to as the Saffman-Taylor problem). For that we develop an alternative approach to the viscous fingering phenomena, whose basic concepts have been recently published in a Rapid Communication [Phys. Rev. E 63, 045305(R) (2001)]. This approach uses the diffusion-limited aggregation (DLA) paradigm as a core: we introduce a mean-field DLA generalization in stochastic and deterministic formulations. The stochastic model, a quasicontinuum DLA, simulates Monte Carlo patterns, which demonstrate a striking resemblance to natural Hele-Shaw fingers and, for steady-state growth regimes, follow precisely the Saffman-Taylor analytical solutions in channel and sector configurations. The relevant deterministic theory, a complete set of differential equations for a time development of density fields, is derived from that stochastic model. As a principal conclusion, we prove an asymptotic equivalency of both the stochastic and deterministic mean-field DLA formulations to the classic Saffman-Taylor hydrodynamics in terms of an interface evolution. PMID:11736272

  3. Finger pain

    MedlinePlus

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

  4. Modeling and Control of Three-Dimensional Grasping by a Pair of Robot Fingers

    NASA Astrophysics Data System (ADS)

    Arimoto, Suguru; Yoshida, Morio

    This paper extends a stability theory of 2-D object grasp to cope with 3-dimensional(3-D) object grasp by a pair of multi-joint robot fingers with hemi-spheric ends. It shows that secure grasp of a 3-D object with parallel surfaces in a dynamic sense can be realized in a blind manner like human grasp an object by a pair of thumb and index finger while their eyes closed. Rolling contacts are modeled as Pfaffian constraints that can not be integrated into holonomic constraints but exert tangential constraint forces on the object surfaces. A noteworthy difference of modeling of 3-D object grasping from the 2-D case is that the instantaneous axis of rotation of the object dynamics of the overall fingers-object system are subject to non-holonomic constraints regarding a 3-D orthogonal matrix consisting of three mutually orthogonal unit-vectors fixed at the object. Lagrange's equation of motion of the overall system can be derived from the variational principle without violating the causality that governs the nonholonomic constraints. Then, a simple control signal constructed on the basis of fingers-thumb opposable forces together with an object-mass estimator is shown to accomplish stable grasp in a dynamic sense without using object information or external sensing. The closed-loop dynamics can be regarded as Lagrange's equation of motion with an artificial potential function that attains its minimum at some equilibrium state of force/torque balance. A mathematical proof of stability and asymptotic stability on a constraint manifold of the closed-loop dynamics under the nonholonomic constraints is presented.

  5. Computing with liquid crystal fingers: models of geometric and logical computation.

    PubMed

    Adamatzky, Andrew; Kitson, Stephen; Costello, Ben De Lacy; Matranga, Mario Ariosto; Younger, Daniel

    2011-12-01

    When a voltage is applied across a thin layer of cholesteric liquid crystal, fingers of cholesteric alignment can form and propagate in the layer. In computer simulation, based on experimental laboratory results, we demonstrate that these cholesteric fingers can solve selected problems of computational geometry, logic, and arithmetics. We show that branching fingers approximate a planar Voronoi diagram, and nonbranching fingers produce a convex subdivision of concave polygons. We also provide a detailed blueprint and simulation of a one-bit half-adder functioning on the principles of collision-based computing, where the implementation is via collision of liquid crystal fingers with obstacles and other fingers. PMID:22304104

  6. Evidence evaluation in fingerprint comparison and automated fingerprint identification systems--modelling within finger variability.

    PubMed

    Egli, Nicole M; Champod, Christophe; Margot, Pierre

    2007-04-11

    Recent challenges and errors in fingerprint identification have highlighted the need for assessing the information content of a papillary pattern in a systematic way. In particular, estimation of the statistical uncertainty associated with this type of evidence is more and more called upon. The approach used in the present study is based on the assessment of likelihood ratios (LRs). This evaluative tool weighs the likelihood of evidence given two mutually exclusive hypotheses. The computation of likelihood ratios on a database of marks of known sources (matching the unknown and non-matching the unknown mark) allows an estimation of the evidential contribution of fingerprint evidence. LRs are computed taking advantage of the scores obtained from an automated fingerprint identification system and hence are based exclusively on level II features (minutiae). The AFIS system attributes a score to any comparison (fingerprint to fingerprint, mark to mark and mark to fingerprint), used here as a proximity measure between the respective arrangements of minutiae. The numerator of the LR addresses the within finger variability and is obtained by comparing the same configurations of minutiae coming from the same source. Only comparisons where the same minutiae are visible both on the mark and on the print are therefore taken into account. The denominator of the LR is obtained by cross-comparison with a database of prints originating from non-matching sources. The estimation of the numerator of the LR is much more complex in terms of specific data requirements than the estimation of the denominator of the LR (that requires only a large database of prints from an non-associated population). Hence this paper addresses specific issues associated with the numerator or within finger variability. This study aims at answering the following questions: (1) how a database for modelling within finger variability should be acquired; (2) whether or not the visualisation technique or the

  7. Behavioral thermoregulatory responses of single- and group-housed mice.

    PubMed

    Gordon, C J; Becker, P; Ali, J S

    1998-11-15

    The ambient temperature (Ta) to house and study laboratory rodents is critical for nearly all biomedical studies. The ideal Ta for housing rodents and other animals should be based on their thermoregulatory requirements. However, fundamental information on the behavioral thermoregulatory responses of single- and group-housed rodents is meager. To address this issue, thermoregulatory behavior was assessed in individual and groups of CD-1 mice housed in a temperature gradient. Mice were housed in groups of five or individually while selected Ta and motor activity were monitored. Single- and group-housed mice displayed a circadian oscillation of selected Ta and motor activity with relatively warm T(a)s of approximately 29 degrees C selected during the light phase; during the dark phase selected Ta was reduced by 4 degrees C, whereas motor activity increased. Selected Ta of aged (11 months old) mice housed individually was approximately 1.0 degrees C warmer than the group-housed mice. Thermal preference of younger mice (2 months old) was similar for single- and group-housed animals. The operative Ta of mice housed in standard facilities was estimated by measuring the cooling rate of "phantom" mice modeled from aluminum cylinders. The results show that the typical housing conditions for single- and group-housed mice are cooler than their Ta for ideal thermal comfort. PMID:9855474

  8. Hidden Markov Model and Support Vector Machine based decoding of finger movements using Electrocorticography

    PubMed Central

    Wissel, Tobias; Pfeiffer, Tim; Frysch, Robert; Knight, Robert T.; Chang, Edward F.; Hinrichs, Hermann; Rieger, Jochem W.; Rose, Georg

    2013-01-01

    Objective Support Vector Machines (SVM) have developed into a gold standard for accurate classification in Brain-Computer-Interfaces (BCI). The choice of the most appropriate classifier for a particular application depends on several characteristics in addition to decoding accuracy. Here we investigate the implementation of Hidden Markov Models (HMM)for online BCIs and discuss strategies to improve their performance. Approach We compare the SVM, serving as a reference, and HMMs for classifying discrete finger movements obtained from the Electrocorticograms of four subjects doing a finger tapping experiment. The classifier decisions are based on a subset of low-frequency time domain and high gamma oscillation features. Main results We show that decoding optimization between the two approaches is due to the way features are extracted and selected and less dependent on the classifier. An additional gain in HMM performance of up to 6% was obtained by introducing model constraints. Comparable accuracies of up to 90% were achieved with both SVM and HMM with the high gamma cortical response providing the most important decoding information for both techniques. Significance We discuss technical HMM characteristics and adaptations in the context of the presented data as well as for general BCI applications. Our findings suggest that HMMs and their characteristics are promising for efficient online brain-computer interfaces. PMID:24045504

  9. Histaminergic neurons in the hypothalamic thermoregulatory pathways

    SciTech Connect

    Lomax, P.; Green, M.D.

    1981-11-01

    Based on neurochemical and neurophysiological research, especially over the past decade, considerable evidence exists for accepting histamine as a central neurotransmitter alongside the other neuroamines. The data supporting a functional role are not complete, but they do exhibit a consistent pattern in the case of the central thermoregulatory pathways. Thus, the region of the thermoregulatory centers in the rostral hypothalamus contains relatively high concentrations of histamine and the enzyme systems for its synthesis and degradation: degeneration studies indicate histaminergic pathways in the hypothalamus; thermoregulatory changes can be induced by activation of either H/sub 1/ or H/sub 2/ receptors; behavioral studies reveal different functional roles for H/sub 1/ and H/sub 2/ receptors; and the thermoregulatory responses to histamine are detectable across different species, even in nonhomeothermic animals. This evidence supports assigning a transmitter function to histamine in the central thermoregulatory pathways that would appear to be as well-founded as the comparable data amassed for other neuroamines.

  10. Observations and modeling of surf zone transverse finger bars at the Gold Coast, Australia

    NASA Astrophysics Data System (ADS)

    Ribas, F.; Doeschate, A. ten; de Swart, H. E.; Ruessink, B. G.; Calvete, D.

    2014-08-01

    The occurrence and characteristics of transverse finger bars at Surfers Paradise (Gold Coast, Australia) have been quantified with 4 years of time-exposure video images. These bars are attached to the inner terrace and have an oblique orientation with respect to the coastline. They are observed during 24 % of the study period, in patches up to 15 bars, with an average lifetime of 5 days and a mean wavelength of 32 m. The bars are observed during obliquely incident waves of intermediate heights. Bar crests typically point toward the incoming wave direction, i.e., they are up-current oriented. The most frequent beach state when bars are present (43 % of the time) is a rhythmic low-tide terrace and an undulating outer bar. A morphodynamic model, which describes the feedback between waves, currents, and bed evolution, has been applied to study the mechanisms for finger bar formation. Realistic positive feedback leading to the formation of the observed bars only occurs if the sediment resuspension due to roller-induced turbulence is included. This causes the depth-averaged sediment concentration to decrease in the seaward direction, enhancing the convergence of sediment transport in the offshore-directed flow perturbations that occur over the up-current bars. The longshore current strength also plays an important role; the offshore root-mean-square wave height and angle must be larger than some critical values (0.5 m and 20∘, respectively, at 18-m depth). Model-data comparison indicates that the modeled bar shape characteristics (up-current orientation) and the wave conditions leading to the bar formation agree with data, while the modeled wavelengths and migration rates are larger than the observed ones. The discrepancies might be because in the model we neglect the influence of the large-scale beach configuration.

  11. Microwave challenges to the thermoregulatory system

    SciTech Connect

    Adair, E.R.

    1988-01-01

    The results of several kinds of experiments have been introduced as evidence in support of the thesis that the thermoregulatory system of endotherms functions no differently in the presence of microwaves than it does in the presence of conventional sources of thermal energy. The thermoregulatory profile, unique for each species, provides the framework for the argument. The results of our experiments have demonstrated the equivalence between T and microwave intensity as they influence individual responses of heat production and heat loss. This equivalence, in turn, allows the prediction of specific alterations in thermoregulatory responses when microwaves are present. Predictions of this kind are possible because the hierarchy of autonomic responses available to any given species is always the same. This fact should provide some comfort to those who profess concern abut the uniqueness of absorbed radiofrequency energy and its fate within the body. Additional comfort can be derived from the demonstration that changes in thermoregulatory responses in the presence of microwaves depend upon the integral of energy absorption by the whole body, not upon energy deposited in some restricted locus such as the PO/AH. It is clear that the circulatory system plays a major role in the distribution of energy deposited during such exposures, a fact already emphasized by others. This fact does not negate the presence of electrical hotspots as predicted on theoretical grounds or as demonstrated dosimetrically, but it does deemphasize their importance as potential deterrents to the efficient mobilization of thermoregulatory responses. The utility of the thermoregulatory profile in research of the kind described here cannot be overemphasized. 26 references.

  12. The Electronic Behavior of Zinc-Finger Protein Binding Sites in the Context of the DNA Extended Ladder Model

    NASA Astrophysics Data System (ADS)

    Oiwa, Nestor; Cordeiro, Claudette; Heermann, Dieter

    2016-05-01

    Instead of ATCG letter alignments, typically used in bioinformatics, we propose a new alignment method using the probability distribution function of the bottom of the occupied molecular orbital (BOMO), highest occupied molecular orbital (HOMO) and lowest unoccupied orbital (LUMO). We apply the technique to transcription factors with Cys2His2 zinc fingers. These transcription factors search for binding sites, probing for the electronic patterns at the minor and major DNA groves. The eukaryotic Cys2His2 zinc finger proteins bind to DNA ubiquitously at highly conserved domains. They are responsible for gene regulation and the spatial organization of DNA. To study and understand these zinc finger DNA-protein interactions, we use the extended ladder in the DNA model proposed by Zhu, Rasmussen, Balatsky & Bishop (2007) te{Zhu-2007}. Considering one single spinless electron in each nucleotide π-orbital along a double DNA chain (dDNA), we find a typical pattern for the bottom of BOMO, HOMO and LUMO along the binding sites. We specifically looked at two members of zinc finger protein family: specificity protein 1 (SP1) and early grown response 1 transcription factors (EGR1). When the valence band is filled, we find electrons in the purines along the nucleotide sequence, compatible with the electric charges of the binding amino acids in SP1 and EGR1 zinc finger.

  13. Multiple Fingers - One Gestalt.

    PubMed

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

    2016-01-01

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

  14. Mallet finger - aftercare

    MedlinePlus

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

  15. Fingering convection induced by atomic diffusion in stars: 3D numerical computations and applications to stellar models

    SciTech Connect

    Zemskova, Varvara; Garaud, Pascale; Deal, Morgan; Vauclair, Sylvie

    2014-11-10

    Iron-rich layers are known to form in the stellar subsurface through a combination of gravitational settling and radiative levitation. Their presence, nature, and detailed structure can affect the excitation process of various stellar pulsation modes and must therefore be modeled carefully in order to better interpret Kepler asteroseismic data. In this paper, we study the interplay between atomic diffusion and fingering convection in A-type stars, as well as its role in the establishment and evolution of iron accumulation layers. To do so, we use a combination of three-dimensional idealized numerical simulations of fingering convection (which neglect radiative transfer and complex opacity effects) and one-dimensional realistic stellar models. Using the three-dimensional simulations, we first validate the mixing prescription for fingering convection recently proposed by Brown et al. (within the scope of the aforementioned approximation) and identify what system parameters (total mass of iron, iron diffusivity, thermal diffusivity, etc.) play a role in the overall evolution of the layer. We then implement the Brown et al. prescription in the Toulouse-Geneva Evolution Code to study the evolution of the iron abundance profile beneath the stellar surface. We find, as first discussed by Théado et al., that when the concurrent settling of helium is ignored, this accumulation rapidly causes an inversion in the mean molecular weight profile, which then drives fingering convection. The latter mixes iron with the surrounding material very efficiently, and the resulting iron layer is very weak. However, taking helium settling into account partially stabilizes the iron profile against fingering convection, and a large iron overabundance can accumulate. The opacity also increases significantly as a result, and in some cases it ultimately triggers dynamical convection. The direct effects of radiative acceleration on the dynamics of fingering convection (especially in the

  16. Thermoregulatory responses to preoptic cooling in unrestrained rabbits

    NASA Technical Reports Server (NTRS)

    Mcewen, G. N., Jr.; Heath, J. E.

    1974-01-01

    Rabbits at ambient temperatures within the thermal neutral zone show two different metabolic responses to preoptic cooling. One response type is defined by a preoptic thermal sensitivity that shifts with ambient temperature and a 'set point' that remains constant. The other response type is defined by a set point that shifts with ambient temperature and a preoptic thermal sensitivity that remains constant. Both response types can be modeled by a single equation. Nonmetabolic thermoregulatory responses are not significantly different between the two response types.

  17. Finger Stiffness.

    PubMed

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

    2015-06-01

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

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

    PubMed

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

    2016-06-01

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

  19. Chalcogen bonding interactions between reducible sulfur and selenium compounds and models of zinc finger proteins.

    PubMed

    Lutz, Patricia B; Bayse, Craig A

    2016-04-01

    Reducible sulfur and selenium (r-S/Se) compounds, defined as sulfur and selenium compounds not in the lowest -2 oxidation state (e.g., -1 to +6), release Zn(2+) from zinc-sulfur proteins such as zinc fingers (ZFs) and metallothionein. A series of density functional theory calculations was performed on donor-acceptor complexes between r-S/Se compounds and models of the Cys2His2, Cys3His and Cys4 ZF sites. These S⋯S/Se chalcogen bonding interactions consist of the donation of electron density from a S lone pair on the ZF model to a S/Se-X antibonding molecular orbital of the r-S/Se compound. The strength of the interaction was shown to be dependent upon the Lewis basicity of the ZF model (Cys4>Cys3His>Cys2His2) and the Lewis acidity of the r-S/Se compound as measured by the energy of the S/Se-X antibonding orbital. Interactions with the softer r-Se compounds were stronger than the r-S compounds, consistent with the greater reactivity of the former with ZF proteins. PMID:26877152

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

    PubMed

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

    2015-04-01

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

  1. Frequency weighting for vibration-induced white finger compatible with exposure-response models.

    PubMed

    Brammer, Anthony J; Pitts, Paul M

    2012-01-01

    An analysis has been performed to derive a frequency weighting for the development of vibration-induced white finger (VWF). It employs a model to compare health risks for pairs of population groups that are selected to have similar health outcomes from operating power tools or machines with markedly different acceleration spectra (rock drills, chain saws, pavement breakers and motorcycles). The model defines the Relative Risk, RR(f(trial)), which is constructed from the ratio of daily exposures and includes a trial frequency weighting that is applied to the acceleration spectra. The trial frequency weighting consists of a frequency-independent primary frequency range, and subordinate frequency ranges in which the response to vibration diminishes, with cut-off frequencies that are changed to influence the magnitude of RR(f(trial)). The frequency weighting so derived when RR(f(trial)) = 1 is similar to those obtained by other methods (W(hf), W(hT)). It consists of a frequency independent range from about 25 Hz to 500 Hz (-3 dB frequencies), with an amplitude cut-off rate of 12 dB/octave below 25 Hz and above 500 Hz. The range is compatible with studies of vasoconstriction in persons with VWF. The results provide further evidence that the ISO frequency weighting may be inappropriate for assessing the risk of developing VWF. PMID:23060253

  2. Finger Multiplication

    ERIC Educational Resources Information Center

    Holmes, Bill

    2010-01-01

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

  3. Changes in thermoregulatory behavior during microwave irradiation

    SciTech Connect

    Adair, E.R.

    1981-10-01

    Voluntary behavioral action is an organism's first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral strategies whenever possible to counteract inhospitable alterations in the exchange of thermal energy between their bodies and the environment. Responses as diverse as the thermotropisms of unicellular organisms and the complex behavior-plus-technology of man's lunar walk share a common purpose--that of providing a hospitable microclimate so that the internal body temperature may be regulated with precision at a characteristic (neutral) level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors ensure minimal involvement of innate mechanisms of heat production and heat loss during thermoregulation, thus conserving the body's energy stores and water.

  4. Incubation temperature modulates post-hatching thermoregulatory behavior in the Madagascar ground gecko, Paroedura pictus.

    PubMed

    Blumberg, Mark S; Lewis, Sean J; Sokoloff, Greta

    2002-09-01

    All vertebrates regulate body temperature within narrow limits, regardless of their physiological capabilities. When do these limits develop, and can they be modified by manipulations of the developmental thermal environment? We addressed these questions by incubating the eggs of the Madagascar ground gecko, Paroedura pictus, at three temperatures and by assessing thermoregulatory behavior in hatchlings. Thermoregulatory behavior was assessed using a two-choice shuttle paradigm, and skin temperatures were measured non-invasively using infrared thermography. The shuttling behavior of hatchlings was systematically affected by the temperature at which they were incubated, and follow-up tests suggested that this effect persisted for at least three weeks post-hatching. The body temperature data from the shuttling experiment were used to model thermoregulatory behavior in a complex thermal environment; the model predicted systematic effects of incubation temperature on thermal preference. The specificity of the alteration in thermoregulatory behavior by incubation temperature is compelling and provides evidence for powerful pre-hatching influences on a fundamental, life-sustaining behavioral process. PMID:12177143

  5. Finger Vein Segmentation from Infrared Images Based on a Modified Separable Mumford Shah Model and Local Entropy Thresholding.

    PubMed

    Vlachos, Marios; Dermatas, Evangelos

    2015-01-01

    A novel method for finger vein pattern extraction from infrared images is presented. This method involves four steps: preprocessing which performs local normalization of the image intensity, image enhancement, image segmentation, and finally postprocessing for image cleaning. In the image enhancement step, an image which will be both smooth and similar to the original is sought. The enhanced image is obtained by minimizing the objective function of a modified separable Mumford Shah Model. Since, this minimization procedure is computationally intensive for large images, a local application of the Mumford Shah Model in small window neighborhoods is proposed. The finger veins are located in concave nonsmooth regions and, so, in order to distinct them from the other tissue parts, all the differences between the smooth neighborhoods, obtained by the local application of the model, and the corresponding windows of the original image are added. After that, veins in the enhanced image have been sufficiently emphasized. Thus, after image enhancement, an accurate segmentation can be obtained readily by a local entropy thresholding method. Finally, the resulted binary image may suffer from some misclassifications and, so, a postprocessing step is performed in order to extract a robust finger vein pattern. PMID:26120357

  6. Finger Vein Segmentation from Infrared Images Based on a Modified Separable Mumford Shah Model and Local Entropy Thresholding

    PubMed Central

    Vlachos, Marios; Dermatas, Evangelos

    2015-01-01

    A novel method for finger vein pattern extraction from infrared images is presented. This method involves four steps: preprocessing which performs local normalization of the image intensity, image enhancement, image segmentation, and finally postprocessing for image cleaning. In the image enhancement step, an image which will be both smooth and similar to the original is sought. The enhanced image is obtained by minimizing the objective function of a modified separable Mumford Shah Model. Since, this minimization procedure is computationally intensive for large images, a local application of the Mumford Shah Model in small window neighborhoods is proposed. The finger veins are located in concave nonsmooth regions and, so, in order to distinct them from the other tissue parts, all the differences between the smooth neighborhoods, obtained by the local application of the model, and the corresponding windows of the original image are added. After that, veins in the enhanced image have been sufficiently emphasized. Thus, after image enhancement, an accurate segmentation can be obtained readily by a local entropy thresholding method. Finally, the resulted binary image may suffer from some misclassifications and, so, a postprocessing step is performed in order to extract a robust finger vein pattern. PMID:26120357

  7. Thermoregulatory responses to environmental toxicants: The interaction of thermal stress and toxicant exposure

    SciTech Connect

    Leon, Lisa R.

    2008-11-15

    Thermal stress can have a profound impact on the physiological responses that are elicited following environmental toxicant exposure. The efficacy by which toxicants enter the body is directly influenced by thermoregulatory effector responses that are evoked in response to high ambient temperatures. In mammals, the thermoregulatory response to heat stress consists of an increase in skin blood flow and moistening of the skin surface to dissipate core heat to the environment. These physiological responses may exacerbate chemical toxicity due to increased permeability of the skin, which facilitates the cutaneous absorption of many environmental toxicants. The core temperature responses that are elicited in response to high ambient temperatures, toxicant exposure or both can also have a profound impact on the ability of an organism to survive the insult. In small rodents, the thermoregulatory response to thermal stress and many environmental toxicants (such as organophosphate compounds) is often biphasic in nature, consisting initially of a regulated reduction in core temperature (i.e., hypothermia) followed by fever. Hypothermia is an important thermoregulatory survival strategy that is used by small rodents to diminish the effect of severe environmental insults on tissue homeostasis. The protective effect of hypothermia is realized by its effects on chemical toxicity as molecular and cellular processes, such as lipid peroxidation and the formation of reactive oxygen species, are minimized at reduced core temperatures. The beneficial effects of fever are unknown under these conditions. Perspective is provided on the applicability of data obtained in rodent models to the human condition.

  8. Alpha adrenoceptors in the rabbit ear thermoregulatory microcirculation.

    PubMed

    Li, Z; Koman, L A; Smith, B P; Gordon, E S; Smith, T L

    1998-03-01

    The rabbit ear microcirculation was analyzed in a chronic unanesthetized model to evaluate alpha adrenergic microvascular control in a thermoregulatory end organ. This model allowed direct measurement of microcirculatory responses without the effects of anesthetics or inflammatory responses induced by acute surgical intervention. The ipsilateral facial artery was catheterized for drug injections into the experimental ear. Microvascular diameter changes following stimulation or blockade of adrenoceptor (AR) subtypes were observed directly through a chronic microvascular chamber implanted in the rabbit ear. Vascular alpha1- and alpha2-ARs appear to be distributed differently across the arterioles and AVAs of the rabbit ear. Both alpha1- and alpha2-ARs appear to contribute to vasoconstriction of AVAs in the conscious rabbit ear. In contrast, alpha1-AR's (vs alpha2-ARs) appear to predominate in adrenergically mediated sympathetic vasoconstriction of arterioles. PMID:9521886

  9. Computer Applications in Thermoregulatory Research.

    ERIC Educational Resources Information Center

    DeMeersman, R. E.; Schneider, Frederick C.

    1984-01-01

    Describes a program which uses a series of algebraic equations calculating mean skin temperature and mean body temperature. The program, which uses the well-established physiological model by Burton, is written in Microsoft BASIC for TRS-80 microcomputers; however, it can be easily modified for other microcomputers. (JN)

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

    PubMed Central

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

    2015-01-01

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

  11. Finger Injuries and Disorders

    MedlinePlus

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

  12. Effects of motion sickness on thermoregulatory responses in a thermoneutral air environment.

    PubMed

    Nobel, Gerard; Tribukait, Arne; Mekjavic, Igor B; Eiken, Ola

    2012-05-01

    Motion sickness (MS) has been identified as a non-thermal factor that can moderate autonomic thermoregulatory responses. It has been shown that MS exaggerates core cooling during immersion in cold (15 °C) and luke-warm (28 °C) water by attenuating cold-induced vasoconstriction. The aim of the present study was to investigate whether MS affects thermal balance in a thermoneutral air environment. Eleven subjects were exposed to rotation in two conditions, control (CN) and MS. In the CN condition subjects refrained from head movements, whereas in the MS condition they performed a sequence of maximal head movements (left, right, up, down) at 15-s intervals until they were very nauseous. Sweating rate, rectal temperature (T(re)), the difference in temperature between the right forearm and tip of the second finger (T(ff)) as an index of cutaneous vasomotor tone, perceived MS, thermal comfort and temperature perception were recorded before and during rotation, and during 90-min post-rotation. During the post-rotation period, T(re) dropped and sweating rate increased in the MS but not in the CN condition. The T(ff) response suggests that MS-induced peripheral vasodilatation which, together with the sweating resulted in increased heat loss. During rotation, subjects perceived temperature to be uncomfortably high, suggesting that MS may also affect thermoregulatory behaviour. It thus appears that also in a thermoneutral air environment MS may substantially affect thermal balance. PMID:21892631

  13. Cardiovascular response to thermoregulatory challenges.

    PubMed

    Liu, Cuiqing; Yavar, Zubin; Sun, Qinghua

    2015-12-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. PMID:26432837

  14. Thermoregulatory correlates of nausea in rats and musk shrews

    PubMed Central

    Ngampramuan, Sukonthar; Cerri, Matteo; Vecchio, Flavia Del; Corrigan, Joshua J.; Kamphee, Amornrat; Dragic, Alexander S.; Rudd, John A.; Romanovsky, Andrej A.; Nalivaiko, Eugene

    2014-01-01

    Nausea is a prominent symptom and major cause of complaint for patients receiving anticancer chemo- or radiation therapy. The arsenal of anti-nausea drugs is limited, and their efficacy is questionable. Currently, the development of new compounds with anti-nausea activity is hampered by the lack of physiological correlates of nausea. Physiological correlates are needed because common laboratory rodents lack the vomiting reflex. Furthermore, nausea does not always lead to vomiting. Here, we report the results of studies conducted in four research centers to investigate whether nausea is associated with any specific thermoregulatory symptoms. Two species were studied: the laboratory rat, which has no vomiting reflex, and the house musk shrew (Suncus murinus), which does have a vomiting reflex. In rats, motion sickness was induced by rotating them in their individual cages in the horizontal plane (0.75 Hz, 40 min) and confirmed by reduced food consumption at the onset of dark (active) phase. In 100% of rats tested at three centers, post-rotational sickness was associated with marked (~1.5°C) hypothermia, which was associated with a short-lasting tail-skin vasodilation (skin temperature increased by ~4°C). Pretreatment with ondansetron, a serotonin 5-HT3 receptor antagonist, which is used to treat nausea in patients in chemo- or radiation therapy, attenuated hypothermia by ~30%. In shrews, motion sickness was induced by a cyclical back-and-forth motion (4 cm, 1 Hz, 15 min) and confirmed by the presence of retching and vomiting. In this model, sickness was also accompanied by marked hypothermia (~2°C). Like in rats, the hypothermic response was preceded by transient tail-skin vasodilation. In conclusion, motion sickness is accompanied by hypothermia that involves both autonomic and thermoeffector mechanisms: tail-skin vasodilation and possibly reduction of the interscapular brown adipose tissue activity. These thermoregulatory symptoms may serve as physiological

  15. Thermoregulatory correlates of nausea in rats and musk shrews.

    PubMed

    Ngampramuan, Sukonthar; Cerri, Matteo; Del Vecchio, Flavia; Corrigan, Joshua J; Kamphee, Amornrat; Dragic, Alexander S; Rudd, John A; Romanovsky, Andrej A; Nalivaiko, Eugene

    2014-03-30

    Nausea is a prominent symptom and major cause of complaint for patients receiving anticancer chemo- or radiation therapy. The arsenal of anti-nausea drugs is limited, and their efficacy is questionable. Currently, the development of new compounds with anti-nausea activity is hampered by the lack of physiological correlates of nausea. Physiological correlates are needed because common laboratory rodents lack the vomiting reflex. Furthermore, nausea does not always lead to vomiting. Here, we report the results of studies conducted in four research centers to investigate whether nausea is associated with any specific thermoregulatory symptoms. Two species were studied: the laboratory rat, which has no vomiting reflex, and the house musk shrew (Suncus murinus), which does have a vomiting reflex. In rats, motion sickness was induced by rotating them in their individual cages in the horizontal plane (0.75 Hz, 40 min) and confirmed by reduced food consumption at the onset of dark (active) phase. In 100% of rats tested at three centers, post-rotational sickness was associated with marked (~1.5°C) hypothermia, which was associated with a short-lasting tail-skin vasodilation (skin temperature increased by ~4°C). Pretreatment with ondansetron, a serotonin 5-HT3 receptor antagonist, which is used to treat nausea in patients in chemo- or radiation therapy, attenuated hypothermia by ~30%. In shrews, motion sickness was induced by a cyclical back-and-forth motion (4 cm, 1 Hz, 15 min) and confirmed by the presence of retching and vomiting. In this model, sickness was also accompanied by marked hypothermia (~2°C). Like in rats, the hypothermic response was preceded by transient tail-skin vasodilation. In conclusion, motion sickness is accompanied by hypothermia that involves both autonomic and thermoeffector mechanisms: tail-skin vasodilation and possibly reduction of the interscapular brown adipose tissue activity. These thermoregulatory symptoms may serve as physiological

  16. Estimating Isometric Tension of Finger Muscle Using Needle EMG Signals and the Twitch Contraction Model

    NASA Astrophysics Data System (ADS)

    Tachibana, Hideyuki; Suzuki, Takafumi; Mabuchi, Kunihiko

    We address an estimation method of isometric muscle tension of fingers, as fundamental research for a neural signal-based prosthesis of fingers. We utilize needle electromyogram (EMG) signals, which have approximately equivalent information to peripheral neural signals. The estimating algorithm comprised two convolution operations. The first convolution is between normal distribution and a spike array, which is detected by needle EMG signals. The convolution estimates the probability density of spike-invoking time in the muscle. In this convolution, we hypothesize that each motor unit in a muscle activates spikes independently based on a same probability density function. The second convolution is between the result of the previous convolution and isometric twitch, viz., the impulse response of the motor unit. The result of the calculation is the sum of all estimated tensions of whole muscle fibers, i.e., muscle tension. We confirmed that there is good correlation between the estimated tension of the muscle and the actual tension, with >0.9 correlation coefficients at 59%, and >0.8 at 89% of all trials.

  17. Noncontacting Finger Seal

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  18. Thermoregulatory vasomotor tone of the rat tail and paws in thermoneutral conditions and its impact on a behavioral model of acute pain.

    PubMed

    El Bitar, Nabil; Pollin, Bernard; Karroum, Elias; Pincedé, Ivanne; Mouraux, André; Le Bars, Daniel

    2014-11-01

    The tail and paws in rodents are heat exchangers involved in the maintenance of core body temperature (T(core)). They are also the most widely used target organs to study acute or chronic "models" of pain. We describe the fluctuations of vasomotor tone in the tail and paws in conditions of thermal neutrality and the constraints of these physiological processes on the responses to thermal nociceptive stimuli, commonly used as an index of pain. Skin temperatures were recorded with a calibrated thermal camera to monitor changes of vasomotor tone in the tail and paws of awake and anesthetized rats. In thermoneutral conditions, the sympathetic tone fluctuated at a rate of two to seven cycles/h. Increased mean arterial blood pressure (MAP; ∼46 mmHg) was followed by increased heart rate (HR; ∼45 beats/min) within 30 s, vasoconstriction of extremities (3.5-7°C range) within 3-5 min, and increased T(core) (∼0.7°C) within 6 min. Decreased MAP was followed by opposite events. There was a high correlation between HR and T(core) recorded 5-6 min later. The reaction time of the animal's response to a radiant thermal stimulus-heat ramp (6°C/s, 20 mm(2) spot) generated by a CO2 laser-directed to the tail depends on these variations. Consequently, the fluctuations in tail and paw temperature thus represent a serious confound for thermal nociceptive tests, particularly when they are conducted at thermal neutrality. PMID:25008410

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

    NASA Astrophysics Data System (ADS)

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

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

  20. Elderly bioheat modeling: changes in physiology, thermoregulation, and blood flow circulation

    NASA Astrophysics Data System (ADS)

    Rida, Mohamad; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-01-01

    A bioheat model for the elderly was developed focusing on blood flow circulatory changes that influence their thermal response in warm and cold environments to predict skin and core temperatures for different segments of the body especially the fingers. The young adult model of Karaki et al. (Int J Therm Sci 67:41-51, 2013) was modified by incorporation of the physiological thermoregulatory and vasomotor changes based on literature observations of physiological changes in the elderly compared to young adults such as lower metabolism and vasoconstriction diminished ability, skin blood flow and its minimum and maximum values, the sweating values, skin fat thickness, as well as the change in threshold parameter related to core or skin temperatures which triggers thermoregulatory action for sweating, maximum dilatation, and maximum constriction. The developed model was validated with published experimental data for elderly exposure to transient and steady hot and cold environments. Predicted finger skin temperature, mean skin temperature, and core temperature were in agreement with published experimental data at a maximum error less than 0.5 °C in the mean skin temperature. The elderly bioheat model showed an increase in finger skin temperature and a decrease in core temperature in cold exposure while it showed a decrease in finger skin temperature and an increase in core temperature in hot exposure.

  1. Phase-field modeling of two-dimensional solute precipitation/dissolution: Solid fingers and diffusion-limited precipitation

    SciTech Connect

    Xu, Zhijie; Meakin, Paul

    2011-01-28

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid-liquid interface posses similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured , close to 1.64, the fractal dimensionality of large square lattice diffusion-limited aggregation (DLA) clusters.

  2. Phase-field modeling of two-dimensional solute precipitation/dissolution: Solid fingers and diffusion-limited precipitation

    SciTech Connect

    Zhijie Xu; Paul Meakin

    2011-01-01

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid–liquid interface has similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured df = 1.68, close to 1.64, the fractal dimensionality of large square lattice DLA clusters.

  3. Phase-field modeling of two-dimensional solute precipitation∕dissolution: solid fingers and diffusion-limited precipitation.

    PubMed

    Xu, Zhijie; Meakin, Paul

    2011-01-28

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid-liquid interface has similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured d(f)=1.68, close to 1.64, the fractal dimensionality of large square lattice DLA clusters. PMID:21280717

  4. Phase-field modeling of two-dimensional solute precipitation/dissolution: Solid fingers and diffusion-limited precipitation

    NASA Astrophysics Data System (ADS)

    Xu, Zhijie; Meakin, Paul

    2011-01-01

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid-liquid interface has similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured d_f = 1.68, close to 1.64, the fractal dimensionality of large square lattice DLA clusters.

  5. Scattering Removal for Finger-Vein Image Restoration

    PubMed Central

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

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

  6. Scattering removal for finger-vein image restoration.

    PubMed

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

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

  7. Behavioral thermoregulatory response to maitotoxin in mice.

    PubMed

    Gordon, C J; Yang, Y; Ramsdell, J S

    1998-10-01

    Many types of marine algal toxins induce marked hypothermic responses in mice. However, it is not known if the thermoregulatory response to these toxins results from dysfunction in the control of core temperature (Tc) or is a coordinated response to lower Tc as occurs with a variety of xenobiotic insults. Female CD-1 mice were administered purified maitotoxin (338 ng/kg; IP) and placed in a temperature gradient for 5 h that permitted the selection of ambient temperatures (Ta) ranging between 15 and 37 degrees C. Tc was monitored simultaneously by radiotelemetric probes that were surgically implanted into the abdominal cavity at least one week before maitotoxin injection. Maitotoxin led to a rapid reduction in Tc from 37 to 34 degrees C within 30 min after injection. There was a simultaneous 4 degrees C reduction in Ta selected by mice within 15 min after injection. Selected Ta recovered rapidly, increased above baseline for approximately one hour, then remained near baseline levels for the remainder of the test period in the gradient. Tc remained approximately 1 to 2 degrees C below control levels throughout the test period. In the temperature gradient, mice can select Ta's warm enough to offset the hypothermic effects of maitotoxin. That cooler Ta's are selected initially after maitotoxin injection suggest that the central neural control of body temperature is affected by the toxin. We postulate that the hypothermic response may represent an adaptive response to enhance survival following exposure to polyether toxins. PMID:9723833

  8. THE EFFECTS OF CHRONIC EXERCISE CONDITIONING ON THERMOREGULATORY RESPONSE TO CHLORPYRIFOS IN FEMALE RATS.

    EPA Science Inventory

    Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set-point) as well as the response to infectious fever. Chlorpyrifos (CHP), an organophosphate pesticide, causes an acute period of hypothermia followed by a delaye...

  9. THE VELOCITY OF DNAPL FINGERING IN WATER-SATURATED POROUS MEDIA LABORATORY EXPERIMENTS AND A MOBILE-IMMOBILE-ZONE MODEL. (R826157)

    EPA Science Inventory

    Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile¯immobile¯zone (MIZ) model is pr...

  10. Influence of aging in the thermoregulatory efficiency of man

    NASA Astrophysics Data System (ADS)

    Mathew, Lazar; Purkayastha, S. S.; Singh, R.; Sen Gupta, J.

    1986-06-01

    Studies were carried out to evaluate the effect of aging on the thermoregulatory efficiency in man. The efficiency of thermoregulatory system was assessed on the basis of tolerance to acute cold stress, Tromp test and cold induced vasodilatation (CIVD) response. The experiments were done in 9 groups (15 each) of human volunteers in the age ranges of 20 25, 26 30, 31 35, 36 40, 41 45, 46 50, 51 55, 56 60 and 61 70 years. They were made to relax in a thermoneutral laboratory (27 ± 1‡C) for one hour; thereafter their resting heart rate, blood pressure, oxygen consumption, oral, mean skin, mean body and peripheral temperatures were measured. Then they were exposed to cold (10‡C) in a cold chamber wearing shorts and vests for two hours. The above parameters and shivering responses were recorded at 30 min intervals during cold exposures. On other occasions, their thermoregulatory efficiency test (Tromp Test) and cold induced vasodilatation response were also studied in the same thermoneutral laboratory. The results showed comparatively poor cold tolerance and thermoregulatory efficiency in elderly people. The middle aged category (above 40 years) showed a gradual reduction in the thermoregulatory efficiency, but highly significant reduction was noticed in those who exceeded sixty years of age.

  11. Thermoregulatory strategy may shape immune investment in Drosophila melanogaster.

    PubMed

    Kutch, Ian C; Sevgili, Hasan; Wittman, Tyler; Fedorka, Kenneth M

    2014-10-15

    As temperatures change, insects alter the amount of melanin in their cuticle to improve thermoregulation. However, melanin is also central to insect immunity, suggesting that thermoregulatory strategy may indirectly impact immune defense by altering the abundance of melanin pathway components (a hypothesis we refer to as thermoregulatory-dependent immune investment). This may be the case in the cricket Allonemobius socius, where warm environments (both seasonal and geographical) produced crickets with lighter cuticles and increased pathogen susceptibility. Unfortunately, the potential for thermoregulatory strategy to influence insect immunity has not been widely explored. Here we address the relationships between temperature, thermoregulatory strategy and immunity in the fruit fly Drosophila melanogaster. To this end, flies from two separate Canadian populations were reared in either a summer- or autumn-like environment. Shortly after adult eclosion, flies were moved to a common environment where their cuticle color and susceptibility to a bacterial pathogen (Pseudomonas aeruginosa) were measured. As with A. socius, individuals from summer-like environments exhibited lighter cuticles and increased pathogen susceptibility, suggesting that the thermoregulatory-immunity relationship is evolutionarily conserved across the hemimetabolous and holometabolous clades. If global temperatures continue to rise as expected, then thermoregulation might play an important role in host infection and mortality rates in systems that provide critical ecosystem services (e.g. pollination), or influence the prevalence of insect-vectored disease (e.g. malaria). PMID:25147243

  12. Hand and Finger Exercises

    MedlinePlus

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

  13. Fluid mixing from viscous fingering.

    PubMed

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

    2011-05-13

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

  14. A thermal manikin with human thermoregulatory control: Implementation and validation

    NASA Astrophysics Data System (ADS)

    Foda, Ehab; Sirén, Kai

    2012-09-01

    Tens of different sorts of thermal manikins are employed worldwide, mainly in the evaluation of clothing thermal insulation and thermal environments. They are regulated thermally using simplified control modes. This paper reports on the implementation and validation of a new thermoregulatory control mode for thermal manikins. The new control mode is based on a multi-segmental Pierce (MSP) model. In this study, the MSP control mode was implemented, using the LabVIEW platform, onto the control system of the thermal manikin `Therminator'. The MSP mode was then used to estimate the segmental equivalent temperature ( t eq) along with constant surface temperature (CST) mode under two asymmetric thermal conditions. Furthermore, subjective tests under the same two conditions were carried out using 17 human subjects. The estimated segmental t eq from the experiments with the two modes and from the subjective assessment were compared in order to validate the use of the MSP mode for the estimation of t eq. The results showed that the t eq values estimated by the MSP mode were closer to the subjective mean votes under the two test conditions for most body segments and compared favourably with values estimated by the CST mode.

  15. A thermal manikin with human thermoregulatory control: implementation and validation.

    PubMed

    Foda, Ehab; Sirén, Kai

    2012-09-01

    Tens of different sorts of thermal manikins are employed worldwide, mainly in the evaluation of clothing thermal insulation and thermal environments. They are regulated thermally using simplified control modes. This paper reports on the implementation and validation of a new thermoregulatory control mode for thermal manikins. The new control mode is based on a multi-segmental Pierce (MSP) model. In this study, the MSP control mode was implemented, using the LabVIEW platform, onto the control system of the thermal manikin 'Therminator'. The MSP mode was then used to estimate the segmental equivalent temperature (t(eq)) along with constant surface temperature (CST) mode under two asymmetric thermal conditions. Furthermore, subjective tests under the same two conditions were carried out using 17 human subjects. The estimated segmental t(eq) from the experiments with the two modes and from the subjective assessment were compared in order to validate the use of the MSP mode for the estimation of t(eq). The results showed that the t(eq) values estimated by the MSP mode were closer to the subjective mean votes under the two test conditions for most body segments and compared favourably with values estimated by the CST mode. PMID:22083406

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

    PubMed Central

    Kodama, Kentaro; Furuyama, Nobuhiro; Inamura, Tetsunari

    2015-01-01

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

  17. Female anthropometric variability and their effects on predicted thermoregulatory responses to work in the heat

    NASA Astrophysics Data System (ADS)

    Yokota, Miyo; Berglund, Larry G.; Bathalon, Gaston P.

    2012-03-01

    The use of thermoregulatory models for assessing physiological responses of workers in thermally stressful situations has been increasing because of the risks and costs related to human studies. In a previous study (Yokota et al. Eur J Appl Physiol 104:297-302, 2008), the effects of anthropometric variability on predicted physiological responses to heat stress in U.S. Army male soldiers were evaluated. Five somatotypes were identified in U.S. Army male multivariate anthropometric distribution. The simulated heat responses, using a thermoregulatory model, were different between somatotypes. The present study further extends this line of research to female soldiers. Anthropometric somatotypes were identified using multivariate analysis [height, weight, percent body fat (%BF)] and the predicted physiological responses to simulated exercise and heat stress using a thermoregulatory model were evaluated. The simulated conditions included walking at ~3 mph (4.8 km/h) for 300 min and wearing battle dress uniform and body armor in a 30°C, 25% relative humidity (RH) environment without solar radiation. Five major somatotypes (tall-fat, tall-lean, average, short-lean, and short-fat), identified through multivariate analysis of anthropometric distributions, showed different tolerance levels to simulated heat stress: lean women were predicted to maintain their core temperatures (Tc) lower than short-fat or tall-fat women. The measured Tc of female subjects obtained from two heat studies (data1: 30°C, 32% RH, protective garments, ~225 w·m-2 walk for 90 min; data2: 32°C, 75% RH, hot weather battle dress uniform, ~378 ± 32 w·m-2 for 30 min walk/30 min rest cycles for 120 min) were utilized for validation. Validation results agreed with the findings in this study: fat subjects tended to have higher core temperatures than medium individuals (data2) and lean subjects maintained lower core temperatures than medium subjects (data1).

  18. THERMOREGULATORY EFFECTS OF METHANOL IN FISCHER AND LONG EVANS RATS

    EPA Science Inventory

    While methanol neurotoxicity has been studied for decades, there are very few data available on the thermoregulatory effects of methanol exposure. his paper will present the results of three studies designed to assess the effects of methanol on body temperature and behavioral the...

  19. Thermoregulatory disorders and illness related to heat and cold stress.

    PubMed

    Cheshire, William P

    2016-04-01

    Thermoregulation is a vital function of the autonomic nervous system in response to cold and heat stress. Thermoregulatory physiology sustains health by keeping body core temperature within a degree or two of 37°C, which enables normal cellular function. Heat production and dissipation are dependent on a coordinated set of autonomic responses. The clinical detection of thermoregulatory impairment provides important diagnostic and localizing information in the evaluation of disorders that impair thermoregulatory pathways, including autonomic neuropathies and ganglionopathies. Failure of neural thermoregulatory mechanisms or exposure to extreme or sustained temperatures that overwhelm the body's thermoregulatory capacity can also result in potentially life-threatening departures from normothermia. Hypothermia, defined as a core temperature of <35.0°C, may present with shivering, respiratory depression, cardiac dysrhythmias, impaired mental function, mydriasis, hypotension, and muscle dysfunction, which can progress to cardiac arrest or coma. Management includes warming measures, hydration, and cardiovascular support. Deaths from hypothermia are twice as frequent as deaths from hyperthermia. Hyperthermia, defined as a core temperature of >40.5°C, may present with sweating, flushing, tachycardia, fatigue, lightheadedness, headache, and paresthesia, progressing to weakness, muscle cramps, oliguria, nausea, agitation, hypotension, syncope, confusion, delirium, seizures, and coma. Mental status changes and core temperature distinguish potentially fatal heat stroke from heat exhaustion. Management requires the immediate reduction of core temperature. Ice water immersion has been shown to be superior to alternative cooling measures. Avoidance of thermal risk and early recognition of cold or heat stress are the cornerstones of preventive therapy. PMID:26794588

  20. Finger snapping during seizures.

    PubMed

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

    2014-01-01

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

  1. Fingers that change color

    MedlinePlus

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

  2. Let your fingers do the walking: A simple spectral signature model for "remote" fossil prospecting.

    PubMed

    Conroy, Glenn C; Emerson, Charles W; Anemone, Robert L; Townsend, K E Beth

    2012-07-01

    Even with the most meticulous planning, and utilizing the most experienced fossil-hunters, fossil prospecting in remote and/or extensive areas can be time-consuming, expensive, logistically challenging, and often hit or miss. While nothing can predict or guarantee with 100% assurance that fossils will be found in any particular location, any procedures or techniques that might increase the odds of success would be a major benefit to the field. Here we describe, and test, one such technique that we feel has great potential for increasing the probability of finding fossiliferous sediments - a relatively simple spectral signature model using the spatial analysis and image classification functions of ArcGIS(®)10 that creates interactive thematic land cover maps that can be used for "remote" fossil prospecting. Our test case is the extensive Eocene sediments of the Uinta Basin, Utah - a fossil prospecting area encompassing ∼1200 square kilometers. Using Landsat 7 ETM+ satellite imagery, we "trained" the spatial analysis and image classification algorithms using the spectral signatures of known fossil localities discovered in the Uinta Basin prior to 2005 and then created interactive probability models highlighting other regions in the Basin having a high probability of containing fossiliferous sediments based on their spectral signatures. A fortuitous "post-hoc" validation of our model presented itself. Our model identified several paleontological "hotspots", regions that, while not producing any fossil localities prior to 2005, had high probabilities of being fossiliferous based on the similarities of their spectral signatures to those of previously known fossil localities. Subsequent fieldwork found fossils in all the regions predicted by the model. PMID:22703969

  3. Acute and delayed thermoregulatory response of mice exposed to brevetoxin.

    PubMed

    Gordon, C J; Kimm-Brinson, K L; Padnos, B; Ramsdell, J S

    2001-09-01

    Thermal dysthesia, characterized by a painful sensation of warm and cool surfaces, is one of many ailments in humans exposed to various marine algal toxins such as brevetoxin (PbTx). There is no animal model to study thermal dysthesia and little is known of the mechanism of action. There is also little known on the acute and delayed thermoregulatory effects of PbTx. In this study, we developed a behavioral system to assess the possible development of thermal dysthesia in mice exposed to PbTx. Female mice were implanted with radiotransmitters to monitor core temperature (Tc) and motor activity (MA). In one experiment, mice were dosed with the control vehicle or 180 microg/kg PbTx and placed on a floor temperature gradient to measure the selected foot temperature (SFT) while air temperature was kept constant. PbTx-treated mice underwent a 10 degrees C reduction in SFT concomitant with a 3 degrees C reduction in Tc within 30 min after exposure. In another study, Tc and MA were monitored in mice maintained in their home cages after dosing with 180 microg/kg PbTx. Tc but not MA increased for 2-5 days after exposure. SFT was unaffected by PbTx when tested 1-12 days after exposure. However, PbTx-treated mice underwent an increase in Tc when placed in the temperature gradient for up to 12 days after exposure. This suggests that PbTx augments the stress-induced hyperthermia from being placed in a novel environment. Overall, acute PbTx exposure leads to a regulated reduction in Tc as characterized by a preference for cooler SFTs and a reduced Tc. Thermal dysthesia was not apparent, but the exaggerated hyperthermic response with a normal SFT in the temperature gradient may suggest an altered processing of thermal stimuli in mice treated with PbTx. PMID:11384725

  4. Behavioral, Ventilatory and Thermoregulatory Responses to Hypercapnia and Hypoxia in the Wistar Audiogenic Rat (WAR) Strain

    PubMed Central

    Giusti, Humberto; Oliveira, José Antonio; Glass, Mogens Lesner; Garcia-Cairasco, Norberto

    2016-01-01

    Introduction We investigated the behavioral, respiratory, and thermoregulatory responses elicited by acute exposure to both hypercapnic and hypoxic environments in Wistar audiogenic rats (WARs). The WAR strain represents a genetic animal model of epilepsy. Methods Behavioral analyses were performed using neuroethological methods, and flowcharts were constructed to illustrate behavioral findings. The body plethysmography method was used to obtain pulmonary ventilation (VE) measurements, and body temperature (Tb) measurements were taken via temperature sensors implanted in the abdominal cavities of the animals. Results No significant difference was observed between the WAR and Wistar control group with respect to the thermoregulatory response elicited by exposure to both acute hypercapnia and acute hypoxia (p>0.05). However, we found that the VE of WARs was attenuated relative to that of Wistar control animals during exposure to both hypercapnic (WAR: 133 ± 11% vs. Wistar: 243 ± 23%, p<0.01) and hypoxic conditions (WAR: 138 ± 8% vs. Wistar: 177 ± 8%; p<0.01). In addition, we noted that this ventilatory attenuation was followed by alterations in the behavioral responses of these animals. Conclusions Our results indicate that WARs, a genetic model of epilepsy, have important alterations in their ability to compensate for changes in levels of various arterial blood gasses. WARs present an attenuated ventilatory response to an increased PaCO2 or decreased PaO2, coupled to behavioral changes, which make them a suitable model to further study respiratory risks associated to epilepsy. PMID:27149672

  5. Rolling friction robot fingers

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1992-01-01

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

  6. Highly Unstable Double-Diffusive Finger Convection in a Hele-Shaw Cell: Baseline Experimental Data for Evaluation of Numerical Models

    SciTech Connect

    PRINGLE,SCOTT E.; COOPER,CLAY A.; GLASS JR.,ROBERT J.

    2000-12-21

    An experimental investigation was conducted to study double-diffusive finger convection in a Hele-Shaw cell by layering a sucrose solution over a more-dense sodium chloride (NaCl) solution. The solutal Rayleigh numbers were on the order of 60,000, based upon the height of the cell (25 cm), and the buoyancy ratio was 1.2. A full-field light transmission technique was used to measure a dye tracer dissolved in the NaCl solution. They analyze the concentration fields to yield the temporal evolution of length scales associated with the vertical and horizontal finger structure as well as the mass flux. These measures show a rapid progression through two early stages to a mature stage and finally a rundown period where mass flux decays rapidly. The data are useful for the development and evaluation of numerical simulators designed to model diffusion and convection of multiple components in porous media. The results are useful for correct formulation at both the process scale (the scale of the experiment) and effective scale (where the lab-scale processes are averaged-up to produce averaged parameters). A fundamental understanding of the fine-scale dynamics of double-diffusive finger convection is necessary in order to successfully parameterize large-scale systems.

  7. Human thermoregulatory system state estimation using non-invasive physiological sensors.

    PubMed

    Buller, Mark J; Castellani, John; Roberts, Warren S; Hoyt, Reed W; Jenkins, Odest Chadwicke

    2011-01-01

    Small teams of emergency workers/military can often find themselves engaged in critical, high exertion work conducted under challenging environmental conditions. These types of conditions present thermal work strain challenges which unmitigated can lead to collapse (heat exhaustion) or even death from heat stroke. Physiological measurement of these teams provides a mechanism that could be an effective tool in preventing thermal injury. While indices of thermal work strain have been proposed they suffer from ignoring thermoregulatory context and rely on measuring internal temperature (IT). Measurement of IT in free ranging ambulatory environments is problematic. In this paper we propose a physiology based Dynamic Bayesian Network (DBN) model that estimates internal temperature, heat production and heat transfer from observations of heart rate, accelerometry, and skin heat flux. We learn the model's conditional probability distributions from seven volunteers engaged in a 48 hour military field training exercise. We demonstrate that sum of our minute to minute heat production estimates correlate well with total daily energy expenditure (TDEE) measured using the doubly labeled water technique (r(2) = 0.73). We also demonstrate that the DBN is able to infer IT in new datasets to within ±0.5 °C over 85% of the time. Importantly, the additional thermoregulatory context allows critical high IT temperature to be estimated better than previous approaches. We conclude that the DBN approach shows promise in enabling practical real time thermal work strain monitoring applications from physiological monitoring systems that exist today. PMID:22255042

  8. Effects of acceleration on thermoregulatory responses of unanesthetized rats

    NASA Technical Reports Server (NTRS)

    Fuller, C. A.; Horowitz, J. M.; Horwitz, B. A.

    1977-01-01

    An experimental study was carried out to examine the thermoregulatory responses of rats to step changes in ambient temperature during centrifugation. Attention is focused on the analysis of problems as to whether the ability of rats to regulate body temperature during one hour of cold exposure is altered by increasing the acceleration field to 2G, whether prior environmental conditioning can affect the temperature response to the combined stressors of acceleration and cold, and whether the orientation of the animal in the acceleration field modifies the temperature response. The finding that the decline in colonic temperature is accompanied by parallel changes in hypothalamic and spinal cord temperatures indicates that the decreasing heat production with increasing heat loss is an atypical thermoregulatory response of these animals to cooling. Mechanical forces acting on the brain may underline the temperature decrease when inverting the animal during acceleration.

  9. Viscoelastic characterization of the primate finger pad in vivo by microstep indentation and three-dimensional finite element models for tactile sensation studies.

    PubMed

    Kumar, Siddarth; Liu, Gang; Schloerb, David W; Srinivasan, Mandayam A

    2015-06-01

    When we touch an object, surface loads imposed on the skin are transmitted to thousands of specialized nerve endings (mechanoreceptors) embedded within the skin. These mechanoreceptors transduce the mechanical signals imposed on them into a neural code of the incident stimuli, enabling us to feel the object. To understand the mechanisms of tactile sensation, it is critical to understand the relationship between the applied surface loads, mechanical state at the mechanoreceptor locations, and transduced neural codes. In this paper, we characterize the bulk viscoelastic properties of the primate finger pad and show its relationship to the dynamic firing rate of SA-1 mechanoreceptors. Two three-dimensional (3D) finite element viscoelastic models, a homogeneous and a multilayer model, of the primate fingertip are developed and calibrated with data from a series of force responses to micro-indentation experiments on primate finger pads. We test these models for validation by simulating indentation with a line load and comparing surface deflection with data in the literature (Srinivasan, 1989, "Surface Deflection of Primate Fingertip Under Line Load," J. Biomech., 22(4), pp. 343-349). We show that a multilayer model with an elastic epidermis and viscoelastic core predicts both the spatial and temporal biomechanical response of the primate finger pad. Finally, to show the utility of the model, ramp and hold indentation with a flat plate is simulated. The multilayer model predicts the strain energy density at a mechanoreceptor location would decay at the same rate as the average dynamic firing rate of SA-1 mechanoreceptors in response to flat plate indentation (previously observed by Srinivasan and LaMotte, 1991 "Encoding of Shape in the Responses of Cutaneous Mechanoreceptors," Information Processing in the Somatosensory System (Wenner-Gren International Symposium Series), O. Franzen and J. Westman, eds., Macmillan Press, London, UK), suggesting that the rate of

  10. Behavioral thermoregulatory response to chlorpyrifos in the rat.

    PubMed

    Gordon, C J

    1997-12-31

    Chlorpyrifos (CHP) is a heavily used organophosphorous-based insecticide that elicits thermoregulatory dysfunction in the rat characterized by an initial period of hypothermia followed by a delayed hyperthermia lasting 24-72 h after exposure. The purpose of the present study was to determine (1) if the delayed hyperthermia is linked to CHP-induced hypothermia and (2) if the hypothermia and delayed hyperthermia are regulated by the CNS thermoregulatory centers. Core temperature (Tc) and motor activity (MA) of female Long-Evans rats were monitored via radiotelemetry. Rats housed in a temperature gradient were administered the control vehicle or CHP (25 mg/kg (p.o.)) while Tc, MA and ambient temperature (Ta) preferred by rats in the gradient (i.e. selected Ta) were recorded. There was an initial reduction in Tc concomitant with a decrease in selected Taa A gradual recovery in Tc occurred during the first night along with a preference for warmer Ta's and depressed MA. The day after CHP there was an elevation in Tc but no change in selected Ta, suggesting that the delayed rise in Tc was regulated. In another experiment, the hypothermic effects of CHP (25 mg/kg (p.o.)) were blocked by raising Ta from 22 to 31 degrees C immediately after CHP administration. Non-heated rats administered CHP underwent a marked period of hypothermia followed by an elevation in diurnal Tc for 2 days. Heated rats showed no hypothermic response but did undergo a hyperthermic response 48 h after CHP. MA was reduced during the first night after CHP in both non-heated and heated groups. Overall, the CHP-induced hyperthermia is not dependent on the development of hypothermia. Behavioral thermoregulatory observations suggest that both hypothermia and hyperthermia are regulated by CNS thermoregulatory centers. PMID:9482118

  11. Finger and toenail onycholysis.

    PubMed

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

    2015-05-01

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

  12. Behavioural thermoregulatory tactics in lacustrine brook charr, Salvelinus fontinalis.

    PubMed

    Bertolo, Andrea; Pépino, Marc; Adams, Julie; Magnan, Pierre

    2011-01-01

    The need to vary body temperature to optimize physiological processes can lead to thermoregulatory behaviours, particularly in ectotherms. Despite some evidence of within-population phenotypic variation in thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. The main objective of this study was to determine whether different thermal tactics exist among individuals of the same population. We studied the behavioural thermoregulation of 33 adult brook charr in a stratified lake using thermo-sensitive radio transmitters that measured hourly individual temperature over one month. The observed behavioural thermoregulatory patterns were consistent between years and suggest the existence of four tactics: two "warm" tactics with both crepuscular and finer periodicities, with or without a diel periodicity, and two "cool" tactics, with or without a diel periodicity. Telemetry data support the above findings by showing that the different tactics are associated with different patterns of diel horizontal movements. Taken together, our results show a clear spatio-temporal segregation of individuals displaying different tactics, suggesting a reduction of niche overlap. To our knowledge, this is the first study showing the presence of behavioural thermoregulatory tactics in a vertebrate. PMID:21490935

  13. Finger cold-induced vasodilation: a review.

    PubMed

    Daanen, H A M

    2003-06-01

    Cold-induced vasodilation (CIVD) in the finger tips generally occurs 5-10 min after the start of local cold exposure of the extremities. This phenomenon is believed to reduce the risk of local cold injuries. However, CIVD is almost absent during hypothermia, when survival of the organism takes precedence over the survival of peripheral tissue. Subjects that are often exposed to local cold (e.g. fish filleters) develop an enhanced CIVD response. Also, differences between ethnic groups are obvious, with black people having the weakest CIVD response. Many other factors affect CIVD, such as diet, alcohol consumption, altitude, age and stress. CIVD is probably caused by a sudden decrease in the release of neurotransmitters from the sympathetic nerves to the muscular coat of the arterio-venous anastomoses (AVAs) due to local cold. AVAs are specific thermoregulatory organs that regulate blood flow in the cold and heat. Their relatively large diameter enables large amounts of blood to pass and convey heat to the surrounding tissue. Unfortunately, information on the quantity of AVAs is lacking, which makes it difficult to estimate the full impact on peripheral blood flow. This review illustrates the thermospecificity of the AVAs and the close link to CIVD. CIVD is influenced by many parameters, but controlled experiments yield information on how CIVD protects the extremities against cold injuries. PMID:12712346

  14. Thermoregulatory physiologic responses in the human body exposed to microwave radiation

    SciTech Connect

    Way, W.I.; Kritikos, H.; Schwan, H.

    1981-01-01

    By introduction of an additional compartment in the hypothalamic region Stolwijk's thermoregulatory model has been modified to consider partial heating due to hot spots induced by microwaves. It was found that because of thermoregulatory action, the temperature of the hypothalamus will not increase drastically until the rate of energy deposition exceeds the threshold level of about 50 mW/g. The primary controlling mechanisms are blood flow and sweating. For an energy deposition rate of 10 mW/g in the hypothalamus the increase in blood flow in the skin is negligible and the temperature rise of the hypothalamus as compared with blood temperature is about 0.5/sup 0/C. It was found that exposure of the head to electromagnetic radiation, in general, causes a decrease in temperature of the trunk and skin. The results show that while the deposition of energy in the hypothalamus at the rate of 10 mW/g produced significant conductive and convective effects, the same total energy uniformly distributed over the cranial cavity produces less significant effects.

  15. Generation of SNCA Cell Models Using Zinc Finger Nuclease (ZFN) Technology for Efficient High-Throughput Drug Screening

    PubMed Central

    Dansithong, Warunee; Paul, Sharan; Scoles, Daniel R.; Pulst, Stefan M.; Huynh, Duong P.

    2015-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disorder caused by loss of dopaminergic neurons of the substantia nigra. The hallmark of PD is the appearance of neuronal protein aggregations known as Lewy bodies and Lewy neurites, of which α-synuclein forms a major component. Familial PD is rare and is associated with missense mutations of the SNCA gene or increases in gene copy number resulting in SNCA overexpression. This suggests that lowering SNCA expression could be therapeutic for PD. Supporting this hypothesis, SNCA reduction was neuroprotective in cell line and rodent PD models. We developed novel cell lines expressing SNCA fused to the reporter genes luciferase (luc) or GFP with the objective to enable high-throughput compound screening (HTS) for small molecules that can lower SNCA expression. Because SNCA expression is likely regulated by far-upstream elements (including the NACP-REP1 located at 8852 bp upstream of the transcription site), we employed zinc finger nuclease (ZFN) genome editing to insert reporter genes in-frame downstream of the SNCA gene in order to retain native SNCA expression control. This ensured full retention of known and unknown up- and downstream genetic elements controlling SNCA expression. Treatment of cells with the histone deacetylase inhibitor valproic acid (VPA) resulted in significantly increased SNCA-luc and SNCA-GFP expression supporting the use of our cell lines for identifying small molecules altering complex modes of expression control. Cells expressing SNCA-luc treated with a luciferase inhibitor or SNCA siRNA resulted in Z’-scores ≥ 0.75, suggesting the suitability of these cell lines for use in HTS. This study presents a novel use of genome editing for the creation of cell lines expressing α-synuclein fusion constructs entirely under native expression control. These cell lines are well suited for HTS for compounds that lower SNCA expression directly or by acting at long-range sites to the SNCA

  16. Finger Cooling During Cold Air Exposure.

    NASA Astrophysics Data System (ADS)

    Tikuisis, Peter

    2004-05-01

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

  17. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  18. THERMOREGULATORY RESPONSES OF THE RABBIT TO CENTRAL NEURAL INJECTION OF SULFOLANE

    EPA Science Inventory

    Systemic exposure of the rabbit to sulfolane results in hypothermia; however, the mechanism of this thermoregulatory effect is unknown. his study was designed to determine the thermoregulatory effects of sulfolane on the central nervous system (CNs) of the rabbit. ale rabbits wer...

  19. A Unique Facility For Metabolic and Thermoregulatory Studies

    NASA Technical Reports Server (NTRS)

    Williamson, Rebecca C.; Webbon, Bruce W.

    1995-01-01

    A unique exercise facility has been developed and used to perform tipper body ergometry tests for space applications. Originally designed to simulate the muscular, cardiovascular and thermoregulatory responses to working in zero gravity, this facility may be used to conduct basic thermoregulatory investigations applicable to multiple sclerosis patients. An environmental chamber houses the tipper body ergometer and permits control of temperature, air now and humidify. The chamber is a closed system and recirculate-s air after conditioning if. A Cybex Lipper body ergometer has been mounted horizontally on the wall of the environmental chamber. In this configuration, the subject lies underneath the arm crank on a supine seat in order to turn the crank. The supine seat can be removed in order to introduce other equipment into the chamber such as a stool to allow upright arm cranking, or a treadmill to allow walk-run experiments. Physiological and environmental signals are fed into a Strawberry Tree data acquisition system while being monitored and logged using the Workbench software program. Physiological monitoring capabilities include 3-lead EKG using an H-P patient monitor, 5 site skin temperature and core temperature using YSI thermistors, and O2 consumption and CO2 production using AMFTFK Applied Electrochemistry analyzers and sensors. This comprehensive data acquisition set tip allows for calculation of various thermoregulatory indices including heat storage, evaporative heat loss, latent heat loss, and metabolic rate. The current system is capable of adding more data acquisition channels if needed. Some potential studies that could be carried out using the facility include: 1) An investigation into the efficiency of cooling various segments of the body to lower Tc 1-2 F. 2) A series of heat and mass balance studies comparing various LCG configurations.

  20. Thermoregulatory consequences of salt loading in the lizard Pogona vitticeps.

    PubMed

    Scarpellini, Carolina da Silveira; Bícego, Kênia C; Tattersall, Glenn J

    2015-04-15

    Previous research has demonstrated that dehydration increases the threshold temperature for panting and decreases the thermal preference of lizards. Conversely, it is unknown whether thermoregulatory responses such as shuttling and gaping are similarly influenced. Shuttling, as an active behavioural response, is considered one of the most effective thermoregulatory behaviours, whereas gaping has been proposed to be involved in preventing brain over-heating in lizards. In this study we examined the effect of salt loading, a proxy for increased plasma osmolality, on shuttling and gaping in Pogona vitticeps. Then, we determined the upper and lower escape ambient temperatures (UETa and LETa), the percentage of time spent gaping, the metabolic rate (V̇O2 ), the evaporative water loss (EWL) during gaping and non-gaping intervals and the evaporative effectiveness (EWL/V̇O2 ) of gaping. All experiments were performed under isotonic (154 mmol l(-1)) and hypertonic saline injections (625, 1250 or 2500 mmol l(-1)). Only the highest concentration of hypertonic saline altered the UETa and LETa, but this effect appeared to be the result of diminishing the animal's propensity to move, instead of any direct reduction in thermoregulatory set-points. Nevertheless, the percentage of time spent gaping was proportionally reduced according to the saline concentration; V̇O2 was also decreased after salt loading. Thermographic images revealed lower head than body surface temperatures during gaping; however this difference was inhibited after salt loading. Our data suggest that EWL/V̇O2 is raised during gaping, possibly contributing to an increase in heat transfer away from the lizard, and playing a role in head or brain cooling. PMID:25714566

  1. Thermoregulatory responses to heat and vibration in men

    NASA Technical Reports Server (NTRS)

    Spaul, W. A.; Spear, R. C.; Greenleaf, J. E.

    1986-01-01

    The effect of vibration on thermoregulatory responses was studied in heat-acclimated men exposed suddenly to simultaneous heat and whole body vibrations (WBVs) at two intensity levels, each at graded frequencies between 5 and 80 Hz. The mean rectal temperature (Tre) became elevated more quickly in the WBV exposures than in the controls (heat exposure alone). Both intensity- and frequency-dependent WBV relationships were recorded in localized blood flows and in sweat rates. Thus, vibration appears to reduce the efficiency of the cooling mechanisms during a heat exposure.

  2. Osseointegrated finger prostheses.

    PubMed

    Doppen, P; Solomons, M; Kritzinger, S

    2009-02-01

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

  3. Multi-fingered robotic hand

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  4. The thermoregulatory theory of yawning: what we know from over 5 years of research

    PubMed Central

    Gallup, Andrew C.; Eldakar, Omar T.

    2012-01-01

    Over the past 5 years numerous reports have confirmed and replicated the specific brain cooling and thermal window predictions derived from the thermoregulatory theory of yawning, and no study has found evidence contrary to these findings. Here we review the comparative research supporting this model of yawning among homeotherms, while highlighting a recent report showing how the expression of contagious yawning in humans is altered by seasonal climate variation. The fact that yawning is constrained to a thermal window of ambient temperature provides unique and compelling support in favor of this theory. Heretofore, no existing alternative hypothesis of yawning can explain these results, which have important implications for understanding the potential functional role of this behavior, both physiologically and socially, in humans and other animals. In discussion we stress the broader applications of this work in clinical settings, and counter the various criticisms of this theory. PMID:23293583

  5. Response of the thermoregulatory system to toxic insults.

    PubMed

    Gordon, Christopher J

    2010-01-01

    The physiological response to environmental toxicants and drugs is modulated by the thermoregulatory system. Environmental and body temperature can affect the entry of toxicants into the body through pulmonary, cutaneous, and gastrointestinal routes. Thermoregulation can ultimately influence the metabolic clearance of chemicals and their toxicity, including lethality. The thermoregulatory response following acute exposure to many toxic chemicals involves a regulated hypothermic response, characterized by activation of autonomic thermoeffectors to raise heat loss and a behavioral preference for cooler temperatures. Moderate hypothermia in rodents improves recovery and survival following toxic exposure. In relatively large mammals, including humans, the hypothermic response is minimal. Fever-like responses are often seen in humans and other large mammals exposed to many toxicants. Fever is also observed in rodents exposed to some toxicants provided that core temperature can be monitored without disturbing the animal (e.g., telemetry). Overall, the universal effects of temperature on chemical toxicity call for researchers to have a better understanding of how body and ambient temperature affect the physiological response to environmental toxicants. PMID:20036879

  6. Thermoregulatory set point decreases after hemorrhage in rats.

    PubMed

    Brown, Justin W; Whitehurst, Marvin E; Gordon, Christopher J; Carroll, Robert G

    2005-03-01

    Hemorrhage in rats causes a drop in body core temperature that is proportional to the hemorrhage volume. We tested the hypothesis that the hemorrhagic hypothermia is due to a downward shift in the thermoregulatory set point. If so, rats subjected to hemorrhage would prefer a cooler ambient temperature to enhance heat loss during the posthemorrhage period. Male Sprague-Dawley rats were fitted with carotid arterial catheters and biotelemetry temperature probes. Two days later, rats were placed in a temperature gradient chamber that allowed the rat to move between ambient temperatures of 15 degrees C to 40 degrees C. Rat location within the gradient was recorded as the selected ambient temperature. After 48 h, a 24 mL/kg hemorrhage was induced via the carotid cannula followed by a 24-h recovery period in the gradient. Body core and selected ambient temperatures significantly decreased after hemorrhage. Within 50 min, selected ambient temperature decreased by 11 degrees C, and returned to normal 100 min after hemorrhage. Within 80 min after hemorrhage, core temperature decreased by 2.3 degrees C, and returned to normal by 8 h after hemorrhage. Expanded analysis of the first hour after hemorrhage showed that reduction in selected ambient temperature preceded the drop in body core temperature. Importantly, the decrease in selected ambient temperature persisted even during the peak decrease in body core temperature. These results indicate that a decrease in thermoregulatory set point contributes to the drop in body core temperature after hemorrhage. PMID:15718921

  7. Do female newts modify thermoregulatory behavior to manipulate egg size?

    PubMed

    Toufarová, Eliška; Gvoždík, Lumír

    2016-04-01

    Reproductive females manipulate offspring phenotypes by modifying conditions during embryogenesis. In ectotherms, the environmental control over embryogenesis is often realized by changes in maternal thermoregulation during gravidity. To determine if reproduction influences thermoregulatory behavior in species where females lay eggs shortly after fertilization (strict oviparity), we compared preferred body temperatures (Tp) between reproductive (egg-laying) and non-reproductive female newts, Ichthyosaura alpestris. Next, we exposed reproductive females to temperatures mimicking Tp ranges of reproductive and non-reproductive individuals to find out whether the maternally modified thermal regime influences ovum and jelly coat volume, and early cleavage rates at the time of oviposition. In the thermal gradient, reproductive females maintained their body temperatures within a narrower range than non-reproductive individuals. The exposure of ovipositing females to temperatures preferred during their reproductive and non-reproductive period had a negligible influence on egg size and early cleavage rates. We conclude that the modification of maternal thermoregulatory behavior provides a limited opportunity to manipulate egg traits in newts. PMID:27033041

  8. Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko.

    PubMed

    Penniket, Sophie; Cree, Alison

    2015-06-01

    Bergmann's rule predicts an increase in body size with decreasing environmental temperature; however, the converse pattern has been found in the majority of lizards studied to date. For these ectotherms, small body size may provide thermal benefits (rapid heat uptake when basking), which would be highly advantageous in cold environments. Yet such an advantage may not exist in nocturnal lizards (which do not avidly bask), in which Bergmann's rule has not been closely studied. We have examined whether the body size of a primarily nocturnal gecko, Woodworthia "Otago/Southland" changed with elevation and operative temperature (determined using physical copper models). In a laboratory study, we investigated whether thermoregulatory mode (heliothermy or thigmothermy) alters the effect of body size on heating and cooling rates. This gecko followed Bergmann's rule, thereby showing the opposite of the dominant pattern in diurnal lizards. Size at maturity, maximum size of adults and size at birth were larger at higher elevations and at lower operative temperatures. Using physical models, we found that large body size can confer thermal benefits for nocturnal lizards that remain within diurnal retreats. Bergmann's rule should not be dismissed for all lizards. Our results clearly support Bergmann's rule for at least one thigmothermic species, for which large body size may provide thermal benefits. Future studies on Bergmann's rule in lizards should consider thermoregulatory mode. We advocate that this ecogeographic rule be examined in relation to operative temperature measured at field sites. Finally, we predict that climate warming may weaken the relationship between body size and elevation in this gecko. PMID:25663371

  9. Repair of webbed fingers - slideshow

    MedlinePlus

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

  10. Three-Fingered Robot Hand

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  11. Spiral viscous fingering.

    NASA Astrophysics Data System (ADS)

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

    2006-11-01

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

  12. A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling

    NASA Astrophysics Data System (ADS)

    Rida, Mohamad; Karaki, Wafaa; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-01-01

    The purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (<32 °C). The second mechanism was activated at a minimum finger skin temperature, T CIVD, min, where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of T CIVD,min was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and T CIVD,min at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and T CIVD,min.

  13. Anthropomorphic finger antagonistically actuated by SMA plates.

    PubMed

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

    2015-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  15. Cold-seeking behavior as a thermoregulatory strategy in systemic inflammation.

    PubMed

    Almeida, Maria C; Steiner, Alexandre A; Branco, Luiz G S; Romanovsky, Andrej A

    2006-06-01

    Systemic inflammation (SI) is a leading cause of hospital death. Although fever and hypothermia are listed as symptoms in every definition of SI, how SI affects thermoregulatory behavior is unclear. SI is often modeled by systemic administration of bacterial lipopolysaccharide (LPS) to rats. When rats are not allowed to regulate their body temperature (Tb) behaviorally, LPS causes either fever or hypothermia, and the direction of the response is determined by LPS dose and ambient temperature (Ta). However, in many studies in which rats were allowed to regulate Tb behaviorally (by selecting their preferred Ta in a thermogradient apparatus), they consistently expressed warmth-seeking behavior and developed fever. We hypothesized that SI can cause not only warmth-seeking behavior but also cold-seeking behavior; we then tested this hypothesis by studying LPS-induced thermoregulatory behavior in adult Wistar rats. A multichannel thermogradient apparatus, implantable data loggers and infrared thermography were used; multiple control experiments were conducted; and the ability of the apparatus to reliably register the changes in rats' preferred Ta induced by thermal (external cooling or heating) or chemical (TRPV1 or TRPM8 agonist) stimuli was confirmed. The rats responded to a low dose of LPS (10 microg/kg i.v.) with warmth-seeking behavior and a polyphasic fever, but to a high dose (5 mg/kg i.v.) with marked cold-seeking behavior and hypothermia followed by warmth-seeking behavior and fever. This is the first well-controlled study to report SI-associated cold-seeking behavior in rats. Cold-seeking behavior is likely to be an important defense response in severe SI. PMID:16820025

  16. Safe Finger Tourniquet--Ideas.

    PubMed

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

    2016-03-01

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

  17. City-Scale Expansion of Human Thermoregulatory Costs

    PubMed Central

    Hill, Richard W.; Muhich, Timothy E.; Humphries, Murray M.

    2013-01-01

    The physiological maintenance of a stable internal temperature by mammals and birds – the phenomenon termed homeothermy – is well known to be energetically expensive. The annual energy requirements of free-living mammals and birds are estimated to be 15–30 times higher than those of similar-size ectothermic vertebrates like lizards. Contemporary humans also use energy to accomplish thermoregulation. They are unique, however, in having shifted thermoregulatory control from the body to the occupied environment, with most people living in cities in dwellings that are temperature-regulated by furnaces and air conditioners powered by exogenous energy sources. The energetic implications of this strategy remain poorly defined. Here we comparatively quantify energy costs in cities, dwellings, and individual human bodies. Thermoregulation persists as a major driver of energy expenditure across these three scales, resulting in energy-versus-ambient-temperature relationships remarkably similar in shape. Incredibly, despite the many and diversified uses of network-delivered energy in modern societies, the energy requirements of six North American cities are as temperature-dependent as the energy requirements of isolated, individual homeotherms. However, the annual per-person energy cost of exogenously powered thermoregulation in cities and dwellings is 9–28 times higher than the cost of endogenous, metabolic thermoregulation of the human body. Shifting the locus of thermoregulatory control from the body to the dwelling achieves climate-independent thermal comfort. However, in an era of amplifying climate change driven by the carbon footprint of humanity, we must acknowledge the energetic extravagance of contemporary, city-scale thermoregulation, which prioritizes heat production over heat conservation. PMID:24143181

  18. Thermoregulatory deficits following prenatal alcohol exposure: structural correlates.

    PubMed

    Zimmerberg, B

    1989-01-01

    Prenatal exposure to alcohol delays the development of thermoregulation in newborn rats. This study examined two possible physiological correlates of this effect. In the first experiment, the effect of prenatal alcohol exposure on the availability of brown adipose tissue for nonshivering thermogenesis was investigated in rat pups from birth to weanling age. Male and female pups were chosen from independent litters with one of three prenatal treatment histories: 35% ethanol-derived calories (35% EDC), pair-fed control (0% EDC), or lab-chow control (LC). Prenatal alcohol exposure resulted in decreased body weight from postnatal (PN) day 1 to 20 compared to controls. Similarly, alcohol-exposed subjects had lighter interscapular brown adipose tissue pads than controls. However, the proportion of brown adipose tissue to body weight in alcohol-exposed pups was not different from controls. It appears that thermoregulatory deficits at birth due to prenatal alcohol exposure are not due to decreased substrate availability. In the second experiment, the relative growth rate of the tail compared to the growth rate of the body was measured in male and female pups from the three prenatal treatment groups. Five-day-old rat pups exposed to alcohol prenatally had relatively slower tail growth than control pups. Since tail growth rate has been associated with ambient temperature, these results suggest that alcohol-exposed rat pups may be experiencing transient periods of cold stress in the nest because of their thermoregulatory deficiencies, which, in turn, could have important implications for neural and body growth retardation seen in Alcohol Related Birth Defects. PMID:2818842

  19. Inspiration-induced vascular responses in finger dorsum skin.

    PubMed

    Mayrovitz, Harvey N; Groseclose, Edye E

    2002-03-01

    A rapid and deep inspiration triggers a sympathetically mediated transient vasoconstriction of skin arterioles (inspiratory gasp vascular response, IGVR). Because the IGVR has been most often measured and studied in skin that is rich in arteriovenous anastomoses (AVAs), such as the palmar aspect of the distal phalanx or plantar aspect of the toes, there is little information on its features in skin areas not dominated by thermoregulatory AVAs. Thus, the dependence of the magnitude of the IGVR on AVAs is unclear. We reasoned that if responses in a region of low AVA density, such as the finger dorsum distal phalanx, were comparable to those in AVA-rich skin, this would clarify the issue. Further, it might then be possible to use such areas to provide a useful complementary target for future study of sympathetically induced vasoconstriction. To test this, we determined the features of the finger dorsum IGVR in 28 healthy volunteers (age 19-57 years, 14 males) in whom distal phalanx skin blood perfusion (SBF) was monitored by laser-Doppler during 21 sequential IGVRs, each separated by 2 min. IGVR was quantified as the minimum SBF during each IGVR, expressed as a percentage of each immediately preceding 2-min SBF average. Results (mean +/- SD) revealed an overall IGVR of 72.2 +/- 16.7%, which is very near that reported from studies on the AVA-rich palmar finger pad. We therefore conclude that the IGVR does not depend on the presence of AVAs and that the dorsal distal phalanx is a viable alternative for the study of sympathetically related neurovascular responses. PMID:11866546

  20. Finger vein image quality evaluation using support vector machines

    NASA Astrophysics Data System (ADS)

    Yang, Lu; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2013-02-01

    In an automatic finger-vein recognition system, finger-vein image quality is significant for segmentation, enhancement, and matching processes. In this paper, we propose a finger-vein image quality evaluation method using support vector machines (SVMs). We extract three features including the gradient, image contrast, and information capacity from the input image. An SVM model is built on the training images with annotated quality labels (i.e., high/low) and then applied to unseen images for quality evaluation. To resolve the class-imbalance problem in the training data, we perform oversampling for the minority class with random-synthetic minority oversampling technique. Cross-validation is also employed to verify the reliability and stability of the learned model. Our experimental results show the effectiveness of our method in evaluating the quality of finger-vein images, and by discarding low-quality images detected by our method, the overall finger-vein recognition performance is considerably improved.

  1. Finger Forces in Clarinet Playing

    PubMed Central

    Hofmann, Alex; Goebl, Werner

    2016-01-01

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

  2. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  3. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  4. Thermoregulatory demands of elite professional America's Cup yacht racing.

    PubMed

    Neville, V; Gant, N; Folland, J P

    2010-06-01

    America's Cup yacht racing predominantly occurs during the summer months under hot and humid conditions, with athletes exposed to the environment for prolonged periods, and yet the thermoregulatory responses to competitive sailing are largely unappreciated. This study aimed to assess the thermoregulatory responses to elite professional big-boat yacht racing, according to crew position and upwind and downwind sailing. Intestinal (T(core)) and skin temperature, fluid balance and regional sweat compositions were measured in two America's Cup crews (n=32) during 100 min of racing. The environmental conditions were as follows: 32 degrees C, 52% RH and 5 m/s wind speed. Subjective race intensity was moderate. Bowmen recorded the greatest elevation in the heart rate (184 +/- 10 beats/min) and T(core) (39.2 degrees C, P<0.01). Both heart rate and T(core) were higher during downwind sailing (P<0.001). Regional skin temperatures were significantly different according to site (P=0.05), with tibia being the lowest (33.3 +/- 1.2 degrees C). The mean sweat loss during racing was 1.34 +/- 0.58 L/h (range: 0.44-2.40 L/h), with bowmen experiencing the greatest loss of sweat (3.7 +/- 0.9% of body mass). The mean fluid intake was highly correlated to sweat loss (r=0.74, P<0.001), with 72 +/- 41% of sweat losses replaced. The mean sodium concentration of sweat was 27.2 +/- 9.2 mmol/L (range: 12.0-43.5 mmol/L) and the total NaCl loss during sailing was 3.8 +/- 2.4 g (range 0.7-10.0 g). America's Cup sailing is a demanding sport that presents considerable challenges to thermoregulation, fluid and electrolyte balance. Certain crew roles (bowmen) present an increased risk of developing exertional heat illness, and for the majority of crew downwind sailing results in greater thermal strain than upwind sailing - which may have implications for clothing selection and boat design. PMID:19558386

  5. Viscous fingering with partial miscible fluids

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  6. The Effect of an Amino Acid Infusion on Central Thermoregulatory Control in Humans

    PubMed Central

    Nakajima, Yasufumi; Takamata, Akira; Matsukawa, Takashi; Sessler, Daniel I.; Kitamura, Yoshihiro; Ueno, Hiroshi; Tanaka, Yoshifumi; Mizobe, Toshiki

    2005-01-01

    Background Administration of protein or amino acids enhances thermogenesis, presumably by stimulating oxidative metabolism. However, hyperthermia results even when thermoregulatory responses are intact, suggesting that amino acids also alter central thermoregulatory control. We thus tested the hypothesis that amino acid infusion increases the thermoregulatory setpoint. Methods Nine male volunteers each participated on four study days in randomized order: 1) intravenous amino acids infused at 4 kJ·kg−1·hr−1 for 2.5 h combined with skin-surface warming; 2) amino acid infusion combined with cutaneous cooling; 3) a saline infusion combined with skin-surface warming; and, 4) saline infusion combined with cutaneous cooling. Results Amino acid infusion increased resting core temperature by 0.3 ± 0.1°C (mean ± SD) and oxygen consumption by 18 ± 12%. Furthermore, amino acid infusion increased the calculated core temperature threshold (triggering core temperature at a designated mean-skin temperature of 34°C) for active cutaneous vasodilation by 0.3 ± 0.3°C, for sweating by 0.2 ± 0.2°C, for thermoregulatory vasoconstriction by 0.3 ± 0.3°C, and for thermogenesis by 0.4 ± 0.5°C. Amino acid infusion did not alter the incremental response intensity (i.e., gain) of thermoregulatory defenses. Conclusions Amino acid infusion increased the metabolic rate and resting core temperature. However, amino acids also produced a synchronous increase in all major autonomic thermoregulatory defense thresholds; the increase in core temperature was identical to the setpoint increase — even in a cold environment with amble potential to dissipate heat. In subjects with intact thermoregulatory defenses, amino acid-induced hyperthermia appears to result from an elevated setpoint increase rather than increased metabolic rate per se. PMID:15108979

  7. Thermoregulatory strategies in an aquatic ectotherm from thermally-constrained habitats: An evaluation of current approaches.

    PubMed

    Piasečná, Karin; Pončová, Alena; Tejedo, Miguel; Gvoždík, Lumír

    2015-08-01

    Many ectotherms employ diverse behavioral adjustments to effectively buffer the spatio-temporal variation in environmental temperatures, whereas others remain passive to thermal heterogeneity. Thermoregulatory studies are frequently performed on species living in thermally benign habitats, which complicate understanding of the thermoregulation-thermoconformity continuum. The need for new empirical data from ectotherms exposed to thermally challenging conditions requires the evaluation of available methods for quantifying thermoregulatory strategies. We evaluated the applicability of various thermoregulatory indices using fire salamander larvae, Salamandra salamandra, in two aquatic habitats, a forest pool and well, as examples of disparate thermally-constrained environments. Water temperatures in the well were lower and less variable than in the pool. Thermal conditions prevented larvae from reaching their preferred body temperature range in both water bodies. In contrast to their thermoregulatory abilities examined in a laboratory thermal gradient, field body temperatures only matched the mean and range of operative temperatures, showing thermal passivity of larvae in both habitats. Despite apparent thermoconformity, thermoregulatory indices indicated various strategies from active thermoregulation, to thermoconformity, and even thermal evasion, which revealed their limited applicability under thermally-constrained conditions. Salamander larvae abandoned behavioral thermoregulation despite varying opportunities to increase their body temperature above average water temperatures. Thermoconformity represents a favored strategy in these ectotherms living in more thermally-constrained environments than those examined in previous thermoregulatory studies. To understand thermal ecology and its impact on population dynamics, the quantification of thermoregulatory strategies of ectotherms in thermally-constrained habitats requires the careful choice of an appropriate

  8. Minimal changes in hypothalamic temperature accompany microwave-induced alteration of thermoregulatory behavior

    SciTech Connect

    Adair, E.R.; Adams, B.W.; Akel, G.M.

    1984-01-01

    This study probed the mechanisms underlying microwave-induced alterations of thermoregulatory behavior. Adult male squirrel monkeys (Saimiri sciureus), trained to regulate the temperature of their immediate environment (Ta) behaviorally, were chronically implanted with Teflon reentrant tubes in the medical preoptic/anterior hypothalamic area (PO/AH), the brainstem region considered to control normal thermoregulatory processes. A Vitek temperature probe inserted into the tube measured PO/AH temperature continuously while changes in thermoregulatory behavior were induced by either brief (10-min) or prolonged (2.5-h) unilateral exposures to planewave 2,450-MHz continuous wave (CW) microwaves (E polarization). Power densities explored ranged from 4 to 20 mW/cm2 (rate of energy absorption (SAR) . 0.05 (W/kg)/cm2)). Rectal temperature and four representative skin temperatures were also monitored, as was the Ta selected by the animal. When the power density was high enough to induce a monkey to select a cooler Ta (8 mW/cm2 and above), PO/AH temperature rose approximately 0.3 degrees C but seldom more. Lower power densities usually produced smaller increases in PO/AH temperature and no reliable change in thermoregulatory behavior. Rectal temperature remained constant while PO/AH temperature rose only 0.2-0.3 degrees C during 2.5-h exposures at 20 mW/cm2 because the Ta selected was 2-3 degrees C cooler than normally preferred. Sometimes PO/AH temperature increments greater than 0.3 degrees C were recorded, but they always accompanied inadequate thermoregulatory behavior. Thus, a PO/AH temperature rise of 0.2-0.3 degrees C, accompanying microwave exposure, appears to be necessary and sufficient to alter thermoregulatory behavior, which ensures in turn that no greater temperature excursions occur in this hypothalamic thermoregulatory center.

  9. Gert Finger Becomes Emeritus Physicist

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  10. Effect of prism adaptation on thermoregulatory control in humans.

    PubMed

    Calzolari, Elena; Gallace, Alberto; Moseley, G Lorimer; Vallar, Giuseppe

    2016-01-01

    The physiological regulation of skin temperature can be modulated not only by autonomic brain regions, but also by a network of higher-level cortical areas involved in the maintenance of a coherent representation of the body. In this study we assessed in healthy participants if the sensorimotor changes taking place during motor adaptation to the lateral displacement of the visual scene induced by wearing prismatic lenses (prism adaptation, PA), and the aftereffects, after prisms' removal, on the ability to process spatial coordinates, were associated with skin temperature regulation changes. We found a difference in thermoregulatory control as a function of the direction of the prism-induced displacement of the visual scene, and the subsequent sensorimotor adaptation. After PA to rightward displacing lenses, with leftward aftereffects (the same directional procedure efficaciously used for ameliorating left spatial neglect in right-brain-damaged patients) the hands' temperature decreased. Conversely, after adaptation to neutral lenses, and PA to leftward displacing lenses, with rightward aftereffects, the temperature of both hands increased. These results suggest a lateral asymmetry in the effects of PA on skin temperature regulation, and a relationship between body spatial representations and homeostatic control in humans. PMID:26354443

  11. Thermoregulatory influences on common carotid blood flow in the dog.

    PubMed

    Baker, M A; Hawkins, M J; Rader, R D

    1982-05-01

    Common carotid blood flow (CCBF) and respiratory water loss (RWL) were measured in dogs resting at ambient temperatures between 25 and 50 degrees C, during hypothalamic heating, and during light and heavy exercise at ambient temperatures of 25 and 35 degrees C. In resting dogs, CCBF varied with the level of RWL. Elevations in CCBF and RWL occurred within seconds of each other during bursts of panting. Mean unilateral CCBF increased from 6.2 ml . min-1 . kg-1 at 25 degrees C to 16.8 ml . min-1 . kg-1 at 45 degrees C, in parallel with increasing RWL. Hypothalamic heating elicited simultaneous elevations in CCBF and RWL, and the level of CCBF was strongly correlated with the hypothalamic temperature. Both CCBF and RWL increased rapidly at the onset of exercise and continued to rise during a 15-min run. Highest rates of blood flow and evaporation occurred during heavy exercise at 35 degrees C. It is concluded that the rate of blood flow through the common carotid arteries in the dog is related to the thermoregulatory needs of the animal, and most of the increased flow occurring during heat stress is destined for evaporative surfaces of the nose, mouth, and tongue. PMID:7096136

  12. A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task

    PubMed Central

    Baston, Chiara; Contin, Manuela; Calandra Buonaura, Giovanna; Cortelli, Pietro; Ursino, Mauro

    2016-01-01

    Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both “stable” and “wearing-off” responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect

  13. A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task.

    PubMed

    Baston, Chiara; Contin, Manuela; Calandra Buonaura, Giovanna; Cortelli, Pietro; Ursino, Mauro

    2016-01-01

    Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both "stable" and "wearing-off" responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect sigmoidal

  14. Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions

    NASA Astrophysics Data System (ADS)

    Fiala, D.; Lomas, K. J.; Stohrer, M.

    A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a non-linear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5°C and 50°C and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels.

  15. Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions.

    PubMed

    Fiala, D; Lomas, K J; Stohrer, M

    2001-09-01

    A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a nonlinear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5 degrees C and 50 degrees C and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels. PMID:11594634

  16. COMPARISON OF RATS OF THE FISCHER 344 AND LONG-EVANS STRAINS IN THEIR AUTONOMIC THERMOREGULATORY RESPONSE TO TRIMETHYLTIN ADMINISTRATION

    EPA Science Inventory

    The purpose of this study was to assess the effect of genetic strain on the acute and long-term thermoregulatory response to the neurotoxicant, trimethyltin (TNT) in rats of the Long-Evans (LE) and Fischer 344 (FCH) strains. n one study basic thermoregulatory responses including ...

  17. Tree-hugging koalas demonstrate a novel thermoregulatory mechanism for arboreal mammals.

    PubMed

    Briscoe, Natalie J; Handasyde, Kathrine A; Griffiths, Stephen R; Porter, Warren P; Krockenberger, Andrew; Kearney, Michael R

    2014-06-01

    How climate impacts organisms depends not only on their physiology, but also whether they can buffer themselves against climate variability via their behaviour. One of the way species can withstand hot temperatures is by seeking out cool microclimates, but only if their habitat provides such refugia. Here, we describe a novel thermoregulatory strategy in an arboreal mammal, the koala Phascolarctos cinereus. During hot weather, koalas enhanced conductive heat loss by seeking out and resting against tree trunks that were substantially cooler than ambient air temperature. Using a biophysical model of heat exchange, we show that this behaviour greatly reduces the amount of heat that must be lost via evaporative cooling, potentially increasing koala survival during extreme heat events. While it has long been known that internal temperatures of trees differ from ambient air temperatures, the relevance of this for arboreal and semi-arboreal mammals has not previously been explored. Our results highlight the important role of tree trunks as aboveground 'heat sinks', providing cool local microenvironments not only for koalas, but also for all tree-dwelling species. PMID:24899683

  18. Dendrites, viscous fingers, and the theory of pattern formation

    NASA Technical Reports Server (NTRS)

    Langer, J. S.

    1989-01-01

    Recent developments in the theory of pattern formation in dendritic crystal growth and viscous fingering in fluids are reviewed. Consideration is given to the discovery that weak capillary forces act as singular perturbations which lead to selection mechanisms in dendritic crystal growth and fingering patterns. Other topics include the conventional thermodynamic model of the solidification of a pure substance from its melt, fingering instability, pattern selection, the solvability theory, dendritic growth rates, the bubble effect discovered by Couder et al. (1986), the dynamics of pattern-forming systems, and snowflake formation.

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

    PubMed

    Sharma, Yashna; Dhawan, Anuj

    2016-05-01

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

  20. Fingering Instabilities in Dewetting Nanofluids

    NASA Astrophysics Data System (ADS)

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

    2008-05-01

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

  1. Fingering instabilities in dewetting nanofluids.

    PubMed

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

    2008-05-01

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

  2. Finger-Circumference-Measuring Device

    NASA Technical Reports Server (NTRS)

    Le, Suy

    1995-01-01

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

  3. Finger Forces in Clarinet Playing.

    PubMed

    Hofmann, Alex; Goebl, Werner

    2016-01-01

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

  4. Modelling of the mechanical behavior of a polyurethane finger interphalangeal joint endoprosthesis after surface modification by ion implantation

    NASA Astrophysics Data System (ADS)

    Beliaev, A.; Svistkov, A.; Iziumov, R.; Osorgina, I.; Kondyurin, A.; Bilek, M.; McKenzie, D.

    2016-04-01

    Production of biocompatible implants made of polyurethane treated with plasma is very perspective. During plasma treatment the surface of polyurethane acquires unique physic-chemical properties. However such treatment may change the mechanical properties of polyurethane which may adversely affect the deformation behaviour of the real implant. Therefore careful study of the mechanical properties of the plasma-modified polyurethane is needed. In this paper, experimental observations of the elastic characteristics of plasma treated polyurethane and modelling of the deformation behaviour of polyurethane bio-implants are reported.

  5. Physical Effort Affects Heatstroke Thermoregulatory Response and Mortality in Rats.

    PubMed

    Geng, Yan; Peng, Na; Liu, Ya-Nan; Li, Xing-Gui; Li, Bing-Lin; Peng, Li-Qiong; Ma, Qiang; Su, Lei

    2015-08-01

    Animals suffering from heatstroke (HS) after physical effort may have different heat-related core temperature (Tc) responses compared with passive HS. In the present study, conscious and unrestrained rats were exposed to ambient temperature (Ta) of 39.5°C ± 0.2°C with or without running (run-heated or rest-heated, respectively) until HS onset, which was defined as the systolic blood pressure starting to drop. In comparison with rest-heated rats, run-heated rats had a significantly shorter latency of HS onset. Physical effort did not have significant influence on hyperthermia severity (43.3°C ± 0.2°C at rest-heated, and 43.4°C ± 0.2°C at run-heated), but it could significantly decrease the thermal load to develop HS (315.1°C ± 37.3°C·min for rest-heated, and 133.5 ± 21.4 °C·min for run-heated). Working component during heat exposure may contribute to a decreased survival rate of HS (46.9% at rest-heated and 31.3% at run-heated). Impaired heat dissipation during recovery may be responsible for relative poor survival of run-heated rats. In both groups, survival was affected by Tc at HS onset and thermal area. Hypothermia (Tc <35°C) developed after HS onset, with no significant difference in Tc,min between the rest-heated and run-heated groups. These thermoregulatory responses to HS after physical effort may provide insight into HS pathophysiology. PMID:26009815

  6. Postexercise thermoregulatory behavior and recovery from exercise in desert iguanas.

    PubMed

    Wagner, E L; Gleeson, T T

    1997-02-01

    Desert iguanas (Dipsosaurus dorsalis) undergo respiratory recovery more rapidly and incur lower energetic costs when they recover from 40 degrees C burst activity at 20 degrees C than when they recover at 40 degrees C. However, a body temperature of 20 degrees C falls well outside the preferred activity temperature range of this species, and imposes several physiological and behavioral liabilities. To determine if exhausted animals would favor a thermal regimen that allows for rapid and inexpensive respiratory recovery, we exercised lizards to exhaustion and allowed them to recover in a laboratory thermal gradient for 180 min. Recovering animals allowed their body temperatures to cool significantly to a mean temperature of 33.5 degrees C during the first 60 min of recovery, and subsequently rewarmed themselves to an average temperature of 38 degrees C for the remainder of their recovery period. Control animals maintained a constant body temperature of 37.7 degrees C throughout the 180-min recovery period. We then exercised animals to exhaustion at 40 degrees C and allowed them to recover for 180 min under a thermal regimen that mimicked that selected by exhausted animals in the previous experiment. Animals recovering under this thermal regimen returned to rates of O2 consumption, removed exercise-generated blood lactate, and incurred energetic costs that were more similar to data previously collected for animals recovering from exercise at a constant 40 degrees C than to data from animals recovering at 20 degrees C. These results suggested that the energetic benefits associated with recovery at 20 degrees C are not of sufficient biological importance to cause a major shift in thermoregulatory behavior. PMID:9035245

  7. Diagnostic model of saliva peptide finger print analysis of oral squamous cell carcinoma patients using weak cation exchange magnetic beads

    PubMed Central

    Jiang, Wei-Peng; Wang, Zhen; Xu, Li-Xin; Peng, Xin; Chen, Feng

    2015-01-01

    Saliva diagnostics utilizing nanotechnology and molecular technologies to detect oral squamous cell carcinoma (OSCC) has become an attractive field of study. However, no specific methods have been established. To refine the diagnostic power of saliva peptide fingerprints for the early detection of OSCC, we screened the expression spectrum of salivary peptides in 40 T1 stage OSCC patients (and healthy controls) using MALDI-TOF-MS combined with magnetic beads. Fifty proteins showed significantly different expression levels in the OSCC samples (P<0.05). Potential biomarkers were also predicted. The novel diagnostic proteomic model with m/z peaks of 1285.6 Da and 1432.2 Da are of certain value for early diagnosis of OSCC. PMID:26182373

  8. The Shape of a Gravity Finger

    SciTech Connect

    Zhan, Lang; Yortsos, Yanis

    2000-09-11

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

  9. Neural correlates of finger gnosis.

    PubMed

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

    2014-07-01

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

  10. Acutely Decreased Thermoregulatory Energy Expenditure or Decreased Activity Energy Expenditure Both Acutely Reduce Food Intake in Mice

    PubMed Central

    Kaiyala, Karl J.; Morton, Gregory J.; Thaler, Joshua P.; Meek, Thomas H.; Tylee, Tracy; Ogimoto, Kayoko; Wisse, Brent E.

    2012-01-01

    Despite the suggestion that reduced energy expenditure may be a key contributor to the obesity pandemic, few studies have tested whether acutely reduced energy expenditure is associated with a compensatory reduction in food intake. The homeostatic mechanisms that control food intake and energy expenditure remain controversial and are thought to act over days to weeks. We evaluated food intake in mice using two models of acutely decreased energy expenditure: 1) increasing ambient temperature to thermoneutrality in mice acclimated to standard laboratory temperature or 2) exercise cessation in mice accustomed to wheel running. Increasing ambient temperature (from 21°C to 28°C) rapidly decreased energy expenditure, demonstrating that thermoregulatory energy expenditure contributes to both light cycle (40±1%) and dark cycle energy expenditure (15±3%) at normal ambient temperature (21°C). Reducing thermoregulatory energy expenditure acutely decreased food intake primarily during the light cycle (65±7%), thus conflicting with the delayed compensation model, but did not alter spontaneous activity. Acute exercise cessation decreased energy expenditure only during the dark cycle (14±2% at 21°C; 21±4% at 28°C), while food intake was reduced during the dark cycle (0.9±0.1 g) in mice housed at 28°C, but during the light cycle (0.3±0.1 g) in mice housed at 21°C. Cumulatively, there was a strong correlation between the change in daily energy expenditure and the change in daily food intake (R2 = 0.51, p<0.01). We conclude that acutely decreased energy expenditure decreases food intake suggesting that energy intake is regulated by metabolic signals that respond rapidly and accurately to reduced energy expenditure. PMID:22936977

  11. Visual Foraging With Fingers and Eye Gaze

    PubMed Central

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

    2016-01-01

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

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

    PubMed Central

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

    2011-01-01

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

  13. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

    PubMed Central

    Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

    2015-01-01

    Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066

  14. THERMOREGULATORY CONSEQUENCES OF LONG-TERM MICROWAVE EXPOSURE AT CONTROLLED AMBIENT TEMPERATURES

    EPA Science Inventory

    The study was designed to identify and measure changes in thermoregulatory response systems, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz CW microwaves 40 hours/week for 15 weeks. Microwave power densities explored were 1 and 5 m...

  15. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

    PubMed

    Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

    2015-01-01

    Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066

  16. A new approach for comparing thermoregulatory responses of subjects with different body sizes

    PubMed Central

    Jay, Ollie; Cramer, Matthew N

    2015-01-01

    The time-dependent assessment of human thermoregulatory responses during exercise, such as changes in core temperature and sweating, are commonplace in research laboratories worldwide. Moreover, researchers wishing to identify potential impairments in these responses due to factors such as obesity, age, disease and injury, must typically adopt a between-group experimental design.

  17. THERMOREGULATORY RESPONSES OF THE RABBIT TO SUBCUTANEOUS INJECTION TO SULFOLANE (JOURNAL VERSION)

    EPA Science Inventory

    The study was designed to determine the thermoregulatory effects of sulfolane on the central nervous system (CNS) of the rabbit. POAH temperature (T sub POAH), ear temperature (T sub e), and metabolic rate (MR) were recorded at an ambient temperature (T sub a) of 15 C. No changes...

  18. Viscous fingering with partially miscible fluids

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  19. Biomechanical Analysis of Force Distribution in Human Finger Extensor Mechanisms

    PubMed Central

    Hu, Dan; Ren, Lei; Howard, David; Zong, Changfu

    2014-01-01

    The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx's dorsum. A novel analytical approach based on the “Principle of Minimum Total Potential Energy” is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo. PMID:25126576

  20. Biomechanical analysis of force distribution in human finger extensor mechanisms.

    PubMed

    Hu, Dan; Ren, Lei; Howard, David; Zong, Changfu

    2014-01-01

    The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx's dorsum. A novel analytical approach based on the "Principle of Minimum Total Potential Energy" is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo. PMID:25126576

  1. Rapid functional plasticity of the somatosensory cortex after finger amputation.

    PubMed

    Weiss, T; Miltner, W H; Huonker, R; Friedel, R; Schmidt, I; Taub, E

    2000-09-01

    Recent research indicates that areas of the primary somatosensory (SI) and primary motor cortex show massive cortical reorganization after amputation of the upper arm, forearm or fingers. Most of these studies were carried out months or several years after amputation. In the present study, we describe cortical reorganization of areas in the SI of a patient who underwent amputation of the traumatized middle and ring fingers of his right hand 10 days before cortical magnetic source imaging data were obtained. Somatosensory-evoked magnetic fields (SEF) to mechanical stimuli to the finger tips were recorded and single moving dipoles were calculated using a realistic volume conductor model. Results reveal that the dipoles representing the second and fifth fingers of the affected hand were closer together than the comparable dipoles of the unaffected hand. Our findings demonstrate that neural cell assemblies in SI which formerly represented the right middle and ring fingers of this amputee became reorganized and invaded by neighbouring cell assemblies of the index and little finger of the same hand. These results indicate that functional plasticity occurs within a period of 10 days after amputation. PMID:11037286

  2. Mesofluidic controlled robotic or prosthetic finger

    SciTech Connect

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

    2013-11-19

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

  3. OB-RL silencing inhibits the thermoregulatory ability of Great Roundleaf Bats (Hipposideros armiger).

    PubMed

    Zhu, Tengteng; Yuan, Lihong; Jones, Gareth; Hua, Panyu; He, Guimei; Chen, Jinping; Zhang, Shuyi

    2014-08-01

    Previous studies have shown that the hormone Leptin has an important role in mammalian heterothermy by regulating metabolism and food intake via lipolysis, as well as adaptive evolution of Leptin in heterothermic bats driven by selected pressure. However, the mechanism of Leptin in heterothermic regulation in mammals is unknown. By combining previous results, we speculated that the Leptin signaling pathway mediated by OB-RL (Leptin receptor long form) in the hypothalamus is important. OB-RL is one of the products of db gene and mainly distributed in the hypothalamus. In this study, we used OB-RL as a molecular marker, combining with the RNA interference technology and physiological/molecular analyses with Hipposideros armiger (a hibernating bat species) as an animal model, to explore the mechanism of Leptin in heterothermic regulation. Our data showed that all of four anti-OB-RL shRNA lentivirus significantly inhibited OB-RL expression (>90%), and the interference efficiency of PSC1742 lentivirus reached the highest value. In situ hybridization proved that PSC1742 lentivirus significantly decreased the OB-RL expression in the hypothalamus, especially in the ventromedial hypothalamic nucleus (VHM, 86.6%). Physiological analysis demonstrated that the thermoregulatory ability of bats (e.g., reducing core body temperature and heart rate) was significantly depressed after OB-RL silencing in the hypothalamus, and animals could not enter torpor state. Our study for the first time proved that the knock-down of OB-RL expression in hypothalamus inhibits heterothermic regulation of bats, and also provided the clues for further analyzing the mechanism of Leptin in the heterothermic regulation of mammals. PMID:24815886

  4. Extreme plasticity in thermoregulatory behaviors of free-ranging black-tailed prairie dogs

    USGS Publications Warehouse

    Lehmer, E.M.; Savage, L.T.; Antolin, M.F.; Biggins, D.E.

    2006-01-01

    In the natural environment, hibernating sciurids generally remain dormant during winter and enter numerous deep torpor bouts from the time of first immergence in fall until emergence in spring. In contrast, black-tailed prairie dogs (Cynomys ludovicianus) remain active throughout winter but periodically enter short and shallow bouts of torpor. While investigating body temperature (Tb) patterns of black-tailed prairie dogs from six separate colonies in northern Colorado, we observed one population that displayed torpor patterns resembling those commonly seen in hibernators. Five individuals in this population experienced multiple torpor bouts in immediate succession that increased in length and depth as winter progressed, whereas 16 prairie dogs in five neighboring colonies remained euthermic for the majority of winter and entered shallow bouts of torpor infrequently. Our results suggest that these differences in torpor patterns did not result from differences in the physiological indicators that we measured because the prairie dogs monitored had similar body masses and concentrations of stored lipids across seasons. Likewise, our results did not support the idea that differences in overwinter Tb patterns between prairie dogs in colonies with differing torpor patterns resulted from genetic differences between populations; genetic analyses of prairie dog colonies revealed high genetic similarity between the populations and implied that individuals regularly disperse between colonies. Local environmental conditions probably played a role in the unusual T b patterns experienced by prairie dogs in the colony where hibernation-like patterns were observed; this population received significantly less rainfall than neighboring colonies during the summer growing seasons before, during, and after the year of the winter in which they hibernated. Our study provides a rare example of extreme plasticity in thermoregulatory behaviors of free-ranging prairie dogs and provides

  5. Analyses of thermoregulatory responses of feeder cattle exposed to simulated heat waves

    NASA Astrophysics Data System (ADS)

    Brown-Brandl, T. M.; Eigenberg, R. A.; Hahn, G. L.; Nienaber, J. A.; Mader, T. L.; Spiers, D. E.; Parkhurst, A. M.

    2005-05-01

    Heat stress in feedlot cattle causes reduced performance, and in the most severe cases, death of the animals, thus causing the loss of millions of dollars in revenue to the cattle industry. A study was designed to evaluate dynamics of thermoregulation and feeding activities when feeder cattle were exposed to simulated heat waves, in comparison with repeated sinusoidal hot and thermoneutral environments. Nine beef steers were randomly assigned to an individual pen in one of three environmental chambers. Each chamber was subjected to each of three temperature regimes (Heatwave simulation from Rockport, Mo., 1995, Heatwave simulation from Columbia, Mo., 1999, and Controlled heat stress treatment of 32±7°C) for a period of 18 days, according to a Latin square treatment design, with a 10-day thermoneutral period (18±7°C) separating treatment periods. Respiration rate, core body temperature, heat production, feed intake, and feeding behavior were measured on each animal for the duration of the experiment. Differences were found in all treatments for all parameters except feeding behavior. It was shown that the two simulated heat waves elicited very different thermoregulatory responses. Based on these results the heat wave centered at Rockport, Mo. in 1995 was devastating because the animals were not acclimated to hot conditions, thus causing an acute response to heat stress. The responses of cattle to conditions at Columbia, Mo. showed some acclimation to heat prior to the peak stress days, and therefore a dampened response was seen. It appears the extreme conditions at Columbia, Mo., 1999 were made severe by environmental conditions not simulated during this study (low wind speed and intensive solar radiation). Overall, it was determined while a cyclic heat stress treatment is a representative model to test heat stress in cattle, further heat stress experiments should be conducted in an actual feedlot.

  6. Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic Signals

    PubMed Central

    Wang, Z.; Ji, Q.; Miller, K. J.; Schalk, Gerwin

    2011-01-01

    Brain–computer interfaces (BCIs) use brain signals to convey a user’s intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG) recordings from the surface of the brain in humans can give information about kinematic parameters (e.g., hand velocity or finger flexion). The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS). Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation. PMID:22144944

  7. Width of a ferrofluid finger: hysteresis and a double energy minimum.

    PubMed

    Hillier, Narelle J; Jackson, David P

    2007-03-01

    We study a ferrofluid in a horizontal Hele-Shaw geometry subjected to a vertical magnetic field. Specifically, we calculate the energy of a single ferrofluid finger using an idealized model for the finger. By minimizing this energy, we find the preferred finger width as a function of the applied field. Our model predicts a first order transition as the fluid abruptly transforms from a circular drop to a finite finger. This behavior arises because of a double energy minimum that yields two different stable configurations for the system. Interestingly, this system exhibits hysteresis as the circle-to-finger (increasing field) transition occurs at a different applied field than the finger-to-circle (decreasing field) transition. We carry out a simple experiment and observe good overall agreement with the theoretical predictions. PMID:17500798

  8. Making fingers and words count in a cognitive robot

    PubMed Central

    De La Cruz, Vivian M.; Di Nuovo, Alessandro; Di Nuovo, Santo; Cangelosi, Angelo

    2013-01-01

    Evidence from developmental as well as neuroscientific studies suggest that finger counting activity plays an important role in the acquisition of numerical skills in children. It has been claimed that this skill helps in building motor-based representations of number that continue to influence number processing well into adulthood, facilitating the emergence of number concepts from sensorimotor experience through a bottom-up process. The act of counting also involves the acquisition and use of a verbal number system of which number words are the basic building blocks. Using a Cognitive Developmental Robotics paradigm we present results of a modeling experiment on whether finger counting and the association of number words (or tags) to fingers, could serve to bootstrap the representation of number in a cognitive robot, enabling it to perform basic numerical operations such as addition. The cognitive architecture of the robot is based on artificial neural networks, which enable the robot to learn both sensorimotor skills (finger counting) and linguistic skills (using number words). The results obtained in our experiments show that learning the number words in sequence along with finger configurations helps the fast building of the initial representation of number in the robot. Number knowledge, is instead, not as efficiently developed when number words are learned out of sequence without finger counting. Furthermore, the internal representations of the finger configurations themselves, developed by the robot as a result of the experiments, sustain the execution of basic arithmetic operations, something consistent with evidence coming from developmental research with children. The model and experiments demonstrate the importance of sensorimotor skill learning in robots for the acquisition of abstract knowledge such as numbers. PMID:24550795

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

    PubMed

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

    2014-01-01

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

  10. Interaction of three-finger proteins from snake venoms and from mammalian brain with the cys-loop receptors and their models.

    PubMed

    Faure, G; Shelukhina, I V; Porowinska, D; Shulepko, M A; Lyukmanova, E N; Dolgikh, D A; Spirova, E N; Kasheverov, I E; Utkin, Yu N; Corringer, J-P; Tsetlin, V I

    2016-05-01

    With the use of surface plasmon resonance (SPR) it was shown that ws-Lynx1, a water-soluble analog of the three-finger membrane-bound protein Lynx1, that modulates the activity of brain nicotinic acetylcholine receptors (nAChRs), interacts with the acetylcholine-binding protein (AChBP) with high affinity, K D = 62 nM. This result agrees with the earlier demonstrated competition of ws-Lynx1 with radioiodinated α-bungarotoxin for binding to AChBP. For the first time it was shown that ws-Lynx1 binds to GLIC, prokaryotic Cys-loop receptor (K D = 1.3 μM). On the contrary, SPR revealed that α-cobratoxin, a three-finger protein from cobra venom, does not bind to GLIC. Obtained results indicate that SPR is a promising method for analysis of topography of ws-Lynx1 binding sites using its mutants and those of AChBP and GLIC. PMID:27417718

  11. Peripheral mechanisms of thermoregulatory control of skin blood flow in aged humans

    PubMed Central

    Kenney, W. Larry

    2010-01-01

    Human skin blood flow is controlled via dual innervation from the sympathetic nervous system. Reflex cutaneous vasoconstriction and vasodilation are both impaired with primary aging, rendering the aged more vulnerable to hypothermia and cardiovascular complications from heat-related illness. Age-related alterations in the thermoregulatory control of skin blood flow occur at multiple points along the efferent arm of the reflex, including 1) diminished sympathetic outflow, 2) altered presynaptic neurotransmitter synthesis, 3) reduced vascular responsiveness, and 4) impairments in downstream (endothelial and vascular smooth muscle) second-messenger signaling. This mechanistic review highlights some of the recent findings in the area of aging and the thermoregulatory control of skin blood flow. PMID:20413421

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  13. To each its own: Thermoregulatory strategy varies among neonatal polar phocids.

    PubMed

    Pearson, Linnea E; Liwanag, Heather E M; Hammill, Mike O; Burns, Jennifer M

    2014-12-01

    Cold environmental conditions and small body size promote heat loss and may create thermoregulatory challenges for marine mammals born in polar regions. However, among polar-born phocid seal species there are variations in physical attributes and environmental conditions at birth, allowing for an interesting contrast in thermoregulatory strategy. We compared thermoregulatory strategies through morphometrics, sculp attributes (conductivity and resistance), nonshivering thermogenesis (NST via uncoupling protein 1; UCP1), and muscle thermogenesis (via enzyme activity) in neonatal harp (Pagophilus groenlandicus), hooded (Cystophora cristata), and Weddell seals (Leptonychotes weddellii). Harp seals are the smallest at birth (9.8±0.7 kg), rely on lanugo (82.49±3.70% of thermal resistance), and are capable of NST through expression of UCP1 in brown adipose tissue (BAT). In contrast, hooded seal neonates (26.8±1.3 kg) have 2.06±0.23 cm of blubber, accounting for 38.19±6.07% of their thermal resistance. They are not capable of NST, as UCP1 is not expressed. The large Weddell seal neonates (31.5±4.9 kg) rely on lanugo (89.85±1.25% of thermal resistance) like harp seals, but no evidence of BAT was found. Muscle enzyme activity was highest in Weddell seal neonates, suggesting that they rely primarily on muscle thermogenesis. Similar total thermal resistance, combined with marked differences in thermogenic capacity of NST and ST among species, strongly supports that thermoregulatory strategy in neonatal phocids is more closely tied to pups' surface area to volume ratio (SA:V) and potential for early water immersion rather than mass and ambient environmental conditions. PMID:25151642

  14. Relationship of osmotic inhibition in thermoregulatory responses and sweat sodium concentration in humans.

    PubMed

    Takamata, A; Yoshida, T; Nishida, N; Morimoto, T

    2001-03-01

    Heat acclimatization improves thermoregulatory responses to heat stress and decreases sweat sodium concentration ([Na(+)](sweat)). The reduced [Na(+)](sweat) results in a larger increase in plasma osmolality (P(osmol)) at a given amount of sweat output. The increase in P(osmol) inhibits thermoregulatory responses to increased body core temperature. Therefore, we hypothesized that the inhibitory effect of plasma hyperosmolality on the thermoregulatory responses to heat stress should be attenuated with the reduction of [Na(+)](sweat) due to heat acclimatization. Eleven subjects (9 male and 2 female) were passively heated by immersing their lower legs into water at 42 degrees C (room temperature 28 degrees C and relative humidity 30%) for 50 min following isotonic or hypertonic saline infusion. We determined the increase in the esophageal temperature (T(es)) required to elicit sweating and cutaneous vasodilation (CVD) (DeltaT(es) thresholds for sweating and CVD, respectively) in each condition and calculated the elevation of the T(es) thresholds per unit increase in P(osmol) as the osmotic inhibition of sweating and CVD. The osmotic shift in the DeltaT(es) thresholds for both sweating and CVD correlated linearly with [Na(+)](sweat) (r = 0.858 and r = 0.628, respectively). Thus subjects with a lower [Na(+)](sweat) showed a smaller osmotic elevation of the DeltaT(es) thresholds for sweating and CVD. These results suggest the possibility that heat acclimatization attenuates osmotic inhibition of thermoregulatory responses as well as reducing [Na(+)](sweat). PMID:11171638

  15. Clay for Little Fingers.

    ERIC Educational Resources Information Center

    Koster, Joan Bouza

    1999-01-01

    Discusses the renewed interest in clay as a modeling compound in early childhood programs; describes the nature of clay and presents a working vocabulary. Suggests methods of working with clay, including introducing clay to children, discovering its uses, clean up, firing clay, and finishing baked clay. Includes activity suggestions and…

  16. Can Newts Cope with the Heat? Disparate Thermoregulatory Strategies of Two Sympatric Species in Water

    PubMed Central

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms. PMID:25993482

  17. Neural substrates for sexual and thermoregulatory behavior in the male leopard gecko, Eublepharis macularius.

    PubMed

    Edwards, Nora; Kriegsfeld, Lance; Crews, David

    2004-12-10

    The preoptic area-anterior hypothalamus (POAH) continuum is critical for the integration of environmental, physiological, and behavioral cues associated with reproduction in vertebrates. In the present study, radiofrequency lesions in the POAH abolished sexual behavior in the leopard gecko (Eublepharis macularius). Furthermore, results suggest a differential effect of POAH lesions on those behaviors regarded as appetitive (tail vibration and grip) and those regarded as consummatory (mounting and copulation), with consummatory behaviors being affected to a greater extent. E. macularius is an ectothermic vertebrate that modulates body temperature behaviorally relative to ambient temperature. In vertebrates, the POAH is also an important integrator of thermoregulation. Thus, the present study investigated whether lesions that disrupt reproductive behavior also disrupt body temperature regulation. While virtually all males displayed diurnal rhythms in thermoregulatory behavior prior to surgery, this pattern was abolished in a small proportion of animals bearing POAH lesions. Lesions that abolished thermoregulatory rhythms involved the suprachiasmatic nucleus (SCN), whereas lesions confined to the POAH, while dramatically influencing sexual behavior, did not affect thermoregulatory rhythms or temperature set point. Together, these findings identify the POAH as an important neural locus regulating sexual behavior but not thermoregulation and suggest that the SCN acts as a pacemaker controlling daily behavioral temperature regulation in this species. PMID:15533318

  18. Altered thermoregulatory responses after 15 days of head-down tilt

    NASA Technical Reports Server (NTRS)

    Crandall, Craig G.; Johnson, John M.; Convertino, Victor A.; Raven, Peter B.; Engelke, Keith A.

    1994-01-01

    To determine whether extended exposure to a simulation of microgravity alters thermoregulatory reflex control of skin blood flow, six adult males were exposed to 15 days of 6 deg head-down tilt (HDT). On an ambulatory control day before HDT exposure and on HDT day 15 the core temperature of each subject was increased by 0.5 - 1.0 C by whole body heating with a water-perfused suit. Mean skin temperature, oral temperature (T (sub or)), mean arterial pressure, and forearm blood flow were measured throughout the protocol. Forearm vascular conductance (FVC) was calculated from the ratio of forearm blood flow to mean arterial pressure. After HDT exposure, the T(sub or) threshold at which reflex thermally induced increases in FVC began was elevated, whereas the slope of the T(sub or)-FVC relationship after this threshold was reduced. Moreover, normothermic FVC and FVC at the highest common T(sub or) between pre- and post-HDT trials were reduced after HDT. These data suggest that HDT exposure reduces thermoregulatory responses to heat stress. The mechanisms resulting in such an impaired thermoregulatory response are unknown but are likely related to the relative dehydration that accompanies this exposure.

  19. Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards

    PubMed Central

    Artacho, Paulina; Saravia, Julia; Ferrandière, Beatriz Decencière; Perret, Samuel; Le Galliard, Jean-François

    2015-01-01

    Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior. PMID:26380689

  20. Can newts cope with the heat? Disparate thermoregulatory strategies of two sympatric species in water.

    PubMed

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms. PMID:25993482

  1. Thermoregulatory effect of alarin, a new member of the galanin peptide family

    PubMed Central

    Mikó, Alexandra; Balla, Péter; Tenk, Judit; Balaskó, Márta; Soós, Szilvia; Székely, Miklós; Brunner, Susanne; Kofler, Barbara; Pétervári, Erika

    2014-01-01

    In the background of obesity, among other factors, regulatory alterations in energy balance affecting peptide systems may also be assumed. Regulation of energy balance does not only involve maintenance of body weight but also that of metabolic rate and core temperature. The contribution of alarin, a new member of the potentially orexigenic galanin peptide family, to the regulation of energy metabolism has been recently suggested. Our aim was to analyze the thermoregulatory effects of alarin in rats.   Adult male Wistar rats received full-length alarin (alarin 1–25), its truncated form (alarin 6–25Cys) or scrambled alarin in various doses intracerebroventricularly at different ambient temperatures. Oxygen consumption, heat loss (assessed by tail skin temperature) and core temperature of rats were recorded in an indirect calorimeter system. Upon alarin injection at 25 °C, an increase in oxygen consumption and continuous tail skin vasoconstriction induced a slow rise in core temperature that reached 0.5 °C by 120 and 1.0 °C by 180 min. At cooler or slightly warmer temperatures similar responses were seen. Neither the truncated nor the scrambled alarin elicited any significant thermoregulatory response, however, the truncated form antagonized the hyperthermic actions of the full-length peptide. Alarin appears to elicit a slow hypermetabolic, hyperthermic response in rats. Such a thermoregulatory response would characterize a catabolic (anorexic and hypermetabolic) mediator. Further investigations are needed to clarify the complex role of alarin in energy homeostasis.

  2. Impact of Finger Type in Fingerprint Authentication

    NASA Astrophysics Data System (ADS)

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

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

  3. Does finger sense predict addition performance?

    PubMed

    Newman, Sharlene D

    2016-05-01

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

  4. The Eagle Nebula's fingers - pointers to the earliest stages of star formation?

    NASA Astrophysics Data System (ADS)

    White, G. J.; Nelson, R. P.; Holland, W. S.; Robson, E. I.; Greaves, J. S.; McCaughrean, M. J.; Pilbratt, G. L.; Balser, D. S.; Oka, T.; Sakamoto, S.; Hasegawa, T.; McCutcheon, W. H.; Matthews, H. E.; Fridlund, C. V. M.; Tothill, N. F. H.; Huldtgren, M.; Deane, J. R.

    1999-02-01

    Molecular line, millimetre/submillimetre continuum, and mid-IR observations are reported of the opaque fingers which cross the Eagle Nebula. The fingers are surprisingly warm when viewed in the CO J= 3-2 lines, with kinetic temperatures approaching 60 K, although the lines are relatively narrow. Most of the mass in the fingers is concentrated in cores which lie at the tips of the fingers, and contain from ~ 10 to 60 Msun, representing 55-80% of the mass of the individual fingers. The integrated mass contained in the three fingers and the nearby extended material is ~ 200 Msun. The velocity fields of the gas are complex and the material is very clumpy. The best evidence for coherent velocity structure is seen running along the central finger, which has a velocity gradient ~ 1.7 km s(-1) pc(-1) . The fingers contain several embedded submm continuum cores, with the most intense located at the tips of the fingers. The continuum spectra of these cores shows that they are much cooler, Tdust ~ 20 K, than Tgas ~ 60 K of their respective fingers. A simple thermal and chemical model of a finger was developed to study the physical environment, which takes into account the external UV illumination ( ~ 1700 G_0), and the chemical and thermal structure of a finger. The model predictions are consistent with all of the available observations. The fingers appear to have been formed after primordial dense clumps in the original cloud were irradiated by the light of its OB stars. These clumps then shielded material lying behind from the photoevaporative dispersal of the cloud, and facilitated the formation of the finger structures. The cores in the tips of the fingers appear to be at a very early stage of pre-protostellar development: there are no embedded infrared sources or molecular outflows present. The pressure inside the cores is just less than that of the surrounding gas, allowing them to be compressed by the external pressure. The cores are probably just starting the final

  5. Comparison of heat and cold stress to assess thermoregulatory dysfunction in hypothyroid rats.

    PubMed

    Gordon, C J; Becker, P; Padnos, B

    2000-12-01

    How borderline impairment of thyroid function can affect thermoregulation is an important issue because of the antithyroidal properties of a many environmental toxicants. This study compared the efficacy of heat and cold stress to identify thermoregulatory deficits in rats subjected to borderline and overt hypothyroidism via subchronic exposure to propylthiouracil (PTU). After 3 wk of exposure to PTU in the drinking water (0, 2.5, 5, 10, and 25 mg/l), rats were subjected to a heat stress challenge (34 degrees C for 2.5 h). After one more week of PTU treatment, the same rats were subjected to a cold stress challenge (7 degrees C for 2.5 h). Core temperature (T(c)) was monitored by radiotelemetry. Baseline T(c) during the light phase was reduced by treatment with 25 mg/l PTU. The rate of rise and overall increase in T(c) during heat stress was attenuated by PTU doses of 10 and 25 mg/l. Cold stress resulted in a 1.0 degrees C increase in T(c) regardless of PTU treatment. The rate of rise in T(c) during the cold stress challenge was similar in all PTU treatment groups. There was a dose-related decrease in serum thyroxine (T(4)) at PTU doses >/=5 mg/l. Serum triiodothyronine (T(3)) was reduced at PTU doses of 5 and 25 mg/l. Serum thyroid-stimulating hormone (TSH) was marginally elevated by PTU treatment. Overall, heat stress was more effective than cold stress for detecting a thermoregulatory deficit in borderline (i.e., 10 mg/l PTU) and overtly hypothyroid rats (i.e., 25 mg/l PTU). A significant thermoregulatory deficit is manifested with a 78% decrease in serum T(4). A thermoregulatory deficit is more correlated with a reduction in serum T(4) compared with T(3). Serum levels of TSH are unrelated to thermoregulatory response to heat and cold stress. PMID:11080070

  6. Moving Fingers under a Stick: A Laboratory Activity

    ERIC Educational Resources Information Center

    Massalha, Taha; Lanir, Yuval; Gluck, Paul

    2011-01-01

    We consider a demonstration in which pupils alternately slide and stop their fingers under a long horizontal rod which they support. The changeover is described in terms of the relevant kinetic and static friction. We present a model calculation, performed on a spreadsheet, which clarifies the process and describes graphically the stepwise…

  7. Current status of ultrasonography of the finger

    PubMed Central

    2016-01-01

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

  8. On the fly finger knuckle print authentication

    NASA Astrophysics Data System (ADS)

    Abe, Narishige; Shinzaki, Takashi

    2014-05-01

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

  9. The interaction of DNA with multi-Cys2His2 zinc finger proteins

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Heermann, Dieter W.

    2015-02-01

    The multi-Cys2His2 (mC2H2) zinc finger protein, like CTCF, plays a central role in the three-dimensional organization of chromatin and gene regulation. The interaction between DNA and mC2H2 zinc finger proteins becomes crucial to better understand how CTCF dynamically shapes the chromatin structure. Here, we study a coarse-grained model of the mC2H2 zinc finger proteins in complexes with DNA, and in particular, we study how a mC2H2 zinc finger protein binds to and searches for its target DNA loci. On the basis of coarse-grained molecular dynamics simulations, we present several interesting kinetic conformational properties of the proteins, such as the rotation-coupled sliding, the asymmetrical roles of different zinc fingers and the partial binding partial dangling mode. In addition, two kinds of studied mC2H2 zinc finger proteins, of CG-rich and AT-rich binding motif each, were able to recognize their target sites and slide away from their non-target sites, which shows a proper sequence specificity in our model and the derived force field for mC2H2-DNA interaction. A further application to CTCF shows that the protein binds to a specific DNA duplex only with its central zinc fingers. The zinc finger domains of CTCF asymmetrically bend the DNA, but do not form a DNA loop alone in our simulations.

  10. Piezoelectric Actuators On A Cold Finger

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  11. 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.

  12. Control of dissected leaf morphology by a Cys(2)His(2) zinc finger transcription factor in the model legume Medicago truncatula

    PubMed Central

    Yu, Jianbin; Ge, Liangfa; Wang, Hongliang; Berbel, Ana; Liu, Yu; Chen, Yuhui; Li, Guangming; Tadege, Million; Wen, Jiangqi; Cosson, Viviane; Mysore, Kirankumar S.; Ratet, Pascal; Madueño, Francisco; Bai, Guihua; Chen, Rujin

    2010-01-01

    Plant leaves are diverse in their morphology, reflecting to a large degree the plant diversity in the natural environment. How different leaf morphology is determined is not yet understood. The leguminous plant Medicago truncatula exhibits dissected leaves with three leaflets at the tip. We show that development of the trifoliate leaves is determined by the Cys(2)His(2) zinc finger transcription factor PALM1. Loss-of-function mutants of PALM1 develop dissected leaves with five leaflets clustered at the tip. We demonstrate that PALM1 binds a specific promoter sequence and down-regulates the expression of the M. truncatula LEAFY/UNIFOLIATA orthologue SINGLE LEAFLET1 (SGL1), encoding an indeterminacy factor necessary for leaflet initiation. Our data indicate that SGL1 is required for leaflet proliferation in the palm1 mutant. Interestingly, ectopic expression of PALM1 effectively suppresses the lobed leaf phenotype from overexpression of a class 1 KNOTTED1-like homeobox protein in Arabidopsis plants. Taken together, our results show that PALM1 acts as a determinacy factor, regulates the spatial-temporal expression of SGL1 during leaf morphogenesis and together with the LEAFY/UNIFOLIATA orthologue plays an important role in orchestrating the compound leaf morphology in M. truncatula. PMID:20498057

  13. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    PubMed

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity. PMID:23785105

  14. Control of thermal balance by a liquid circulating garment based on a mathematical representation of the human thermoregulatory system. Ph.D. Thesis - California Univ., Berkeley

    NASA Technical Reports Server (NTRS)

    Kuznetz, L. H.

    1976-01-01

    Test data and a mathematical model of the human thermoregulatory system were used to investigate control of thermal balance by means of a liquid circulating garment (LCG). The test data were derived from five series of experiments in which environmental and metabolic conditions were varied parametrically as a function of several independent variables, including LCG flowrate, LCG inlet temperature, net environmental heat exchange, surrounding gas ventilation rate, ambient pressure, metabolic rate, and subjective/obligatory cooling control. The resultant data were used to relate skin temperature to LCG water temperature and flowrate, to assess a thermal comfort band, to demonstrate the relationship between metabolic rate and LCG heat dissipation, and so forth. The usefulness of the mathematical model as a tool for data interpretation and for generation of trends and relationships among the various physiological parameters was also investigated and verified.

  15. Effects of exercise conditioning on thermoregulatory response to anticholinesterase insecticide toxicity.

    PubMed

    Rowsey, P J; Metzger, B L; Gordon, C J

    2001-04-01

    Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set point) as well as the response to infectious fever Chlorpyrifos (CHP), an organophosphate insecticide, also affects thermoregulation, causing an acute period of hypothermia followed by a delayed fever. This study examined whether chronic exercise training in the rat alters the thermoregulatory response to CHP. Core temperature and motor activity were monitored by radiotelemetry in female Sprague-Dawley rats housed individually at an ambient temperature of 22 degrees C. The rats were either given continuous access to running wheels or housed in standard cages without wheels. The exercise group ran predominately at night. After 8 weeks, the rats were gavaged with corn oil or 15 mg/kg CHP. CHP induced a transient hypothermic response followed by a delayed fever, beginning 1 day after exposure. Relative to controls, T7 decreases were not significantly different between the exercise (1.6 degrees C) group and the sedentary (0.5 degrees C) group given CHP. The sedentary and exercise group administered CHP developed a fever the day after CHP treatment. The fever response was greater in the sedentary group and persisted for approximately 3 days post-injection. Fever of the exercise group persisted for just one-half of 1 day after CHP. It is well known that chronic exercise training improves aerobic capacity; however, trained rats were not protected from the hypothermic effects of CHP. Training did ameliorate the febrile effects of CHP. Thus, exercise training may afford protection to the toxic effects of organophosphate insecticides. PMID:11876466

  16. Role of alpha-1 adrenoceptor subtypes mediating constriction of the rabbit ear thermoregulatory microvasculature.

    PubMed

    Li, Z; Silver, W P; Koman, L A; Strandhoy, J W; Rosencrance, E; Gordon, S; Smith, T L

    2000-01-01

    An acute in vivo preparation of the microvasculature of the rabbit ear was used to evaluate the functional role of alpha1 (alpha1)-adrenoceptor subtypes in thermoregulatory microcirculation. The effect of alpha1-adrenoceptor subtype blockade on phenylephrine-induced vasoconstriction was assessed with the alpha1A, alpha1B, and alpha1D-adrenoceptor-selective antagonists 5-methyl-urapidil (10(-8) M), chloroethylclonidine (10(-5) M), and 8-[2-[4(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspirol[4.5]deca ne-7,9-dione dihydrochloride (BMY7378) (10(-6) M), respectively. The results demonstrated that pretreatment of the ear microvasculature with 5-methyl-urapidil or BMY7378 shifted the phenylephrine concentration-response curve rightward and significantly changed the log of the phenylephrine concentration, causing half-maximum stimulation (EC50) in arterioles (p < 0.05). BMY7378 shifted the phenylephrine concentration-response curve of the arteriovenous anastomoses about 100-fold rightward (p < 0.05). All three alpha1-adrenoceptor antagonists eliminated the vasoconstrictive effects of phenylephrine on venules. The results indicate that the ear microvasculature has a heterogenous distribution of alpha1-adrenoceptor subtypes. The alpha1A and alpha1D-adrenoceptor subtypes appear to have a greater influence on constrictive function in arterioles, whereas the alpha1D-adrenoceptor is the dominant constrictor of arteriovenous anastomoses. In general, the alpha1-adrenoceptor does not play a major vasoconstrictor role in venules. Chloroethylclonidine, an irreversible alpha1B-adrenoceptor antagonist, induced contractile responses in the ear microvasculature, probably due to its alpha2-adrenoceptor agonist effects. This study extended our understanding of the adrenergic receptor control mechanisms of a cutaneous thermoregulatory end organ characterized by two parallel perfusion circuits providing nutritional and thermoregulatory functions. PMID:10716292

  17. Age-dependent differences in the thermoregulatory response of the immature rat to ethanol.

    PubMed

    Spiers, D E; Fusco, L E

    1991-02-01

    Major improvement in the homeothermic ability of the rat occurs during the first 2 weeks of postnatal development. Changes in thermoregulatory responsiveness to a single injection of ethanol (EtOH) may occur during this period. Immature rats (2-3, 8-9, and 14-15 days of age) were administered either saline or EtOH (2 or 4 g/kg BW; ip) at thermoneutral ambient temperatures (Ta). In one experiment, metabolic rate (MR) and body temperatures (colonic and skin) were recorded for 1-3 hr postinjection. A second experiment determined blood EtOH concentration in rats from the 3 age groups over an 8-hr period following injection of EtOH. 4 g EtOH/kg produced few significant reductions in thermoregulatory function of 2-3 day-old rats, but decreased MR by 16% and colonic temperature by 0.5-0.7 degrees C in 8-15 day-old animals. 2 g EtOH/kg had no effect on 8-9 day-old rats, but reduced MR and colonic temperature in rats aged 14-15 days. In every case, the hypothermic response to EtOH was correlated with a reduction in MR. Back and abdominal skin temperatures decreased with colonic temperature, and tail skin temperature indicated EtOH-induced vasoconstriction in older rats. Blood EtOH concentrations were similar in the three age groups during the first 2 hr postinjection and did not explain differences in metabolic response. The magnitude and duration of thermoregulatory responsiveness to EtOH increases with age in the immature rat. PMID:2024730

  18. Thermoregulatory uncoupling in heart muscle mitochondria: involvement of the ATP/ADP antiporter and uncoupling protein.

    PubMed

    Simonyan, R A; Skulachev, V P

    1998-09-25

    Possible involvement of the ATP/ADP antiporter and uncoupling protein (UCP) in thermoregulatory uncoupling of oxidative phosphorylation in heart muscle has been studied. To this end, effects of carboxyatractylate (cAtr) and GDP, specific inhibitors of the antiporter and UCP, on the membrane potential of the oligomycin-treated mitochondria from cold-exposed (6 degrees C, 48 h) and control rats have been measured. It is found that cAtr increases the membrane potential level in both cold-exposed and non-exposed groups, the effect being strongly enhanced by cooling. As for GDP, it is effective only in mitochondria from the cold-exposed rats. In these mitochondria, the coupling effect of GDP is smaller than that of cAtr. CDP, which does not interact with UCP, is without any influence on membrane potential. The cold exposure is found to increase the uncoupling efficiency of added natural (palmitate) or artificial (SF6847) uncouplers, the increase being cAtr- and GDP-sensitive in the case of palmitate. The fatty acid-free bovine serum albumin enhances delta psi in both cold-exposed and control groups, the effect being much larger in the former case. It is concluded that in heart muscle mitochondria the ATP/ADP antiporter is responsible for the 'mild uncoupling' under normal conditions and for major portion of the thermoregulatory uncoupling in the cold whereas the rest of thermoregulatory uncoupling is served by UCP (presumably by UCP2 since the UCP2 mRNA level is shown to strongly increase in rat heart muscle under the cold exposure conditions used). PMID:9771898

  19. Interindividual differences in the thermoregulatory response to cool exposure in sleeping neonates.

    PubMed

    Bach, V; Telliez, F; Zoccoli, G; Lenzi, P; Leke, A; Libert, J P

    2000-04-01

    The responses of the thermoregulatory effectors vary greatly among neonates. Therefore, we assume that a small decrease in air temperature from thermoneutrality induces various thermoregulatory responses within neonates that represent an energy cost due to the cold defence processes. To determine the importance of this variability in nursing, 26 neonates were explored at thermoneutrality and in a cool environment (-1.5 degrees C from thermoneutrality) similar to that which occurs currently in clinical procedure. Oxygen consumption (VO2), oesophageal and skin temperatures, as well as sleep parameters were recorded continuously in both conditions. Analysis of all of the data from all of the neonates revealed that the cool exposure induced thermal and sleep disturbances, but VO2 did not increase and was not negatively correlated to body temperature (as might be expected). Analyses of individual data showed large variability in body temperature regulation: the neonates could be assigned to one of three groups according to the direction of the individual slopes of VO2 versus oesophageal or skin temperature. The groups also differed according to the sleep changes recorded in the cool condition. The results show that the definition of thermoneutrality should be revised by incorporating non only changes in the body temperature, but also the sleep disturbances (increased wakefulness and active sleep, decreased quiet sleep), which are criteria that are more sensitive to mild cool exposure. Thermoneutrality should be defined for each individual, since the results stress that the variability does not help to predict a general pattern of thermoregulatory responses in cool-exposed neonates. PMID:10774868

  20. The effect of ageing and fitness on thermoregulatory response to high-intensity exercise.

    PubMed

    Best, S; Caillaud, C; Thompson, M

    2012-08-01

    There are conflicting reports as to whether ageing causes a decreased thermoregulatory response, or if observed differences in previous studies are related to maximal aerobic capacity or training status. This study hypothesized that thermoregulatory response to severe exercise-heat stress is maintained with ageing when both young and older subjects are well trained. Seven older highly trained (OHT = 51-63 years) cyclists were matched with two groups of young cyclists (19-35 years); one group matched for training status [young highly trained (YHT) participants, n = 7] and another for V ˙ O 2 max [young moderately trained (YMT), n = 7]. Each participant exercised at 70% V ˙ O 2 max in hot (35°C, 40% relative humidity) and thermoneutral (20°C, 40% relative humidity) conditions for 60 min. Final rectal temperature in the thermoneutral and heat (YHT = 39.13 ± 0.33°C, YMT = 39.11 ± 0.38°C, OHT = 39.11 ± 0.51°C) tests were similar between all three groups. %HR(max) (heat test: YHT = 92.5 ± 6.0%, YMT = 91.6 ± 4.4%, OHT = 88.6 ± 5.1%), skin temperature, and cutaneous vascular conductance during cycling in both environments were similar between groups. Lower sweat loss and evaporative heat loss in the heat test in the OHT and YMT groups when compared with the YHT group reflected lower metabolic heat production. The findings of the present study suggest that thermoregulatory response is maintained with age among highly trained subjects. PMID:22092378

  1. Mild evaporative cooling applied to the torso provides thermoregulatory benefits during running in the heat.

    PubMed

    Filingeri, D; Fournet, D; Hodder, S; Havenith, G

    2015-06-01

    We investigated the effects of mild evaporative cooling applied to the torso, before or during running in the heat. Nine male participants performed three trials: control-no cooling (CTR), pre-exercise cooling (PRE-COOL), and during-exercise cooling (COOL). Trials consisted of 10-min neutral exposure and 50-min heat exposure (30 °C; 44% humidity), during which a 30-min running protocol (70% VO2max ) was performed. An evaporative cooling t-shirt was worn before the heat exposure (PRE-COOL) or 15 min after the exercise was started (COOL). PRE-COOL significantly lowered local skin temperature (Tsk ) (up to -5.3 ± 0.3 °C) (P < 0.001), mean Tsk (up to -2 ± 0.1 °C) (P < 0.001), sweat losses (-143 ± 40 g) (P = 0.002), and improved thermal comfort (P = 0.001). COOL suddenly lowered local Tsk (up to -3.8 ± 0.2 °C) (P < 0.001), mean Tsk (up to -1 ± 0.1 °C) (P < 0.001), heart rate (up to -11 ± 2 bpm) (P = 0.03), perceived exertion (P = 0.001), and improved thermal comfort (P = 0.001). We conclude that the mild evaporative cooling provided significant thermoregulatory benefits during exercise in the heat. However, the timing of application was critical in inducing different thermoregulatory responses. These findings provide novel insights on the thermoregulatory role of Tsk during exercise in the heat. PMID:25943671

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed Central

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

    2009-01-01

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

  4. Evaluation of thermoregulatory response to microwave power deposition

    SciTech Connect

    Stolwijk, J.A.J.

    1981-10-01

    The deposition of electromagnetic energy as heat in all of the human body, or in specific parts of it is one of the specific conditions which lend themselves uniquely to a preliminary evaluation through simulation modeling. In general the use of one of the widely accepted models of thermoregulation to evaluate the thermal effects of exposure to radiofrequency electromagnetic radiation should be seen as a useful tool which should be interpreted with reasonable caution.

  5. Mechanics of finger-tip electronics

    NASA Astrophysics Data System (ADS)

    Su, Yewang; Li, Rui; Cheng, Huanyu; Ying, Ming; Bonifas, Andrew P.; Hwang, Keh-Chih; Rogers, John A.; Huang, Yonggang

    2013-10-01

    Tactile sensors and electrotactile stimulators can provide important links between humans and virtual environments, through the sensation of touch. Soft materials, such as low modulus silicones, are attractive as platforms and support matrices for arrays sensors and actuators that laminate directly onto the fingertips. Analytic models for the mechanics of three dimensional, form-fitting finger cuffs based on such designs are presented here, along with quantitative validation using the finite element method. The results indicate that the maximum strains in the silicone and the embedded devices are inversely proportional to the square root of radius of curvature of the cuff. These and other findings can be useful in formulating designs for these and related classes of body-worn, three dimensional devices.

  6. Surface Tension and Fingering of Miscible Interfaces

    NASA Technical Reports Server (NTRS)

    Abib, Mohammed; Liu, Jian-Bang; Ronney, Paul D.

    1999-01-01

    Experiments on miscible, buoyantly unstable reaction-diffusion fronts and non-reacting displacement fronts in Hele-Shaw cells show a fingering-type instability whose wavelengths (lambda*) are consistent with an interfacial tension (sigma) at the front caused by the change in chemical composition, even though the solutions are miscible in all proportions. In conjunction with the Saffman-Taylor model, the relation sigma = K/tau, where tau is the interface thickness and K approximately equal 4 +/- 2 x 10(exp -6) dyne, enables prediction of our measured values of lambda* as well as results from prior experiments on miscible interfaces. These results indicate that even for miscible fluids, surface tension is generally a more significant factor than diffusion in interfacial stability and flow characteristics.

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

    PubMed

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

    2007-08-01

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

  8. 50 years of computer simulation of the human thermoregulatory system.

    PubMed

    Hensley, Daniel W; Mark, Andrew E; Abella, Jayvee R; Netscher, George M; Wissler, Eugene H; Diller, Kenneth R

    2013-02-01

    This paper presents an updated and augmented version of the Wissler human thermoregulation model that has been developed continuously over the past 50 years. The existing Fortran code is translated into C with extensive embedded commentary. A graphical user interface (GUI) has been developed in Python to facilitate convenient user designation of input and output variables and formatting of data presentation. Use of the code with the GUI is described and demonstrated. New physiological elements were added to the model to represent the hands and feet, including the unique vascular structures adapted for heat transfer associated with glabrous skin. The heat transfer function and efficacy of glabrous skin is unique within the entire body based on the capacity for a very high rate of blood perfusion and the novel capability for dynamic regulation of blood flow. The model was applied to quantify the absolute and relative contributions of glabrous skin flow to thermoregulation for varying levels of blood perfusion. The model also was used to demonstrate how the unique features of glabrous skin blood flow may be recruited to implement thermal therapeutic procedures. We have developed proprietary methods to manipulate the control of glabrous skin blood flow in conjunction with therapeutic devices and simulated the effect of these methods with the model. PMID:23445051

  9. Creating Number Semantics through Finger Movement Perception

    ERIC Educational Resources Information Center

    Badets, Arnaud; Pesenti, Mauro

    2010-01-01

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

  10. Local and global thermoregulatory responses to MRI electromagnetic fields: Biological effects and safety aspects of nuclear magnetic resonance imaging and spectroscopy

    SciTech Connect

    Gordon, C.J.

    1991-01-01

    During magnetic resonance imaging (MRI) procedures, a subject is exposed to three novel environmental stimuli which have drawn attention over the past decade as potential health hazards: (1) a relatively intense static magnetic field; (2) a time-varying magnetic field, and (3) a radiofrequency (RF) field. Thermoregulation is one of many physiological systems that can be affected by MRI, specifically by the RF radiation absorbed by the subject during MRI. While there is some sparse, albeit controversial data on the possible effects of static magnetic fields on thermoregulation, the major concern regarding potential health hazards of the MRI-induced thermal effects centers on the RF radiation absorbed by a subject during a scan. The purpose of the paper is to review the studies that have impacted on understanding the thermoregulatory effects of MRI with special emphasis on the problems of selecting appropriate animal models for assessing the potential risk of RF radiation exposure during MRI.

  11. Analysis and treatment of finger sucking.

    PubMed Central

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

    2000-01-01

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

  12. Thermoregulatory effects of caffeine ingestion during rest and exercise in men

    NASA Technical Reports Server (NTRS)

    Dunagan, Nancy; Greenleaf, John E.; Cisar, Craig J.

    1994-01-01

    Body temperatures and thermoregulatory responses were measured at rest and during submaximal exercise under normal ambient conditions in 11 aerobically-conditioned men (age = 29.2 +/- 6.2 yr, VO2(max) = 3.73 +/- 0.46 min(sup -1), relative body fat = 12.3 +/- 3.7 percent, mean +/- SD) with (CT) and without (NCT) the ingestion of 10 mg of caffeine per kg of body weight. Oxygen uptake (VO2), heart rate (HR), and rectal (T(sub re)) and mean skin (T-bar(sub sk)) temperatures were recorded for 100 minutes starting one minute after ingestion of caffeine or a placebo. Data were collected throughout 30 minutes of rest (sitting) and the following 70 minutes of sitting leg ergometer exercise using the same constant load (1,088 +/- 153 kgm/min) in both NCT and CT. The load resulted in a mean relative exercise intensity equal to approximately 68 percent of VO2(sub max). Skin heat conductance (H(sub sk)) and sweat rate were calculated. Two-way analysis of covariance revealed no significant (P greater than 0.05) differences between NCT and CT in VO2, HR, T(sub re), T-bar(sub sk), or H(sub sk). A dependent t-test indicated no significant difference between NCT and CT in sweat rate. Thus, a high level of caffeine ingestion has no detrimental effects on body temperatures and thermoregulatory responses during moderately heavy exercise in normal ambient conditions.

  13. Characterization of the thermoregulatory response to pituitary adenylate cyclase-activating polypeptide in rodents.

    PubMed

    Banki, Eszter; Pakai, Eszter; Gaszner, Balazs; Zsiboras, Csaba; Czett, Andras; Bhuddi, Paras Rahul Parkash; Hashimoto, Hitoshi; Toth, Gabor; Tamas, Andrea; Reglodi, Dora; Garami, Andras

    2014-11-01

    Administration of the long form (38 amino acids) of pituitary adenylate cyclase-activating polypeptide (PACAP38) into the central nervous system causes hyperthermia, suggesting that PACAP38 plays a role in the regulation of deep body temperature (T b). In this study, we investigated the thermoregulatory role of PACAP38 in details. First, we infused PACAP38 intracerebroventricularly to rats and measured their T b and autonomic thermoeffector responses. We found that central PACAP38 infusion caused dose-dependent hyperthermia, which was brought about by increased thermogenesis and tail skin vasoconstriction. Compared to intracerebroventricular administration, systemic (intravenous) infusion of the same dose of PACAP38 caused significantly smaller hyperthermia, indicating a central site of action. We then investigated the thermoregulatory phenotype of mice lacking the Pacap gene (Pacap (-/-)). Freely moving Pacap (-/-) mice had higher locomotor activity throughout the day and elevated deep T b during the light phase. When the Pacap (-/-) mice were loosely restrained, their metabolic rate and T b were lower compared to their wild-type littermates. We conclude that PACAP38 causes hyperthermia via activation of the autonomic cold-defense thermoeffectors through central targets. Pacap (-/-) mice express hyperkinesis, which is presumably a compensatory mechanism, because under restrained conditions, these mice are hypometabolic and hypothermic compared to controls. PMID:24994541

  14. Attenuated thermoregulatory responses with increased plasma osmolality in obese subjects during two seasons

    NASA Astrophysics Data System (ADS)

    Kanikowska, Dominika; Sato, Maki; Sugenoya, Junichi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Iwase, Satoshi

    2013-09-01

    Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0 ± 4.9 kg/m2) and five non-obese (BMI, 23.2 ± 2.9 kg/m2) men participated in this experiment at latitude 35°10' N and longitude 136°57.9'E. The average atmospheric temperature was 29.1 ± 1.0 °C in summer and 3.3 ± 1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.

  15. The relative influences of exercise and coat-type on the thermoregulatory responses of cattle

    NASA Astrophysics Data System (ADS)

    Vajrabukka, C.; Thwaites, C. J.

    1984-03-01

    Field and climatic chamber studies revealed that walking at 4.5 km/h elicited greater thermoregulatory responses in Hereford cattle than did the possession of a wooly hair coat. Under mild field conditions, walking caused sweating rate to increase to 150 200 g/m2/h within one hour (P<0.001); no significant differences were recorded between wooly-coated and clipped cattle. Walking at 4.5 km/h on a treadmill in a climate chamber at 38°C and 34 mm Hg water vapour pressure elevated rectal (P<0.001) and skin (P<0.05) temperatures to levels considerably above those in stationary controls. There were no differential effects on sweating or respiratory rates, though the latter were generally higher in the exercising group. Differences in skin temperature, sweating and respiratory rates between coat-types and exercise groups in the climate chamber were similar, but exercise resulted in a much greater rectal temperature response. Overall, exercise represented a more potent thermoregulatory stimulus than a wooly hair coat.

  16. Thermoregulatory consequences of resonant microwave exposure. Final report, August 1987-December 1989

    SciTech Connect

    Adair, E.R.

    1990-06-01

    Four experiments were conducted in which it was shown that behavioral and autonomic thermo-regulatory responses are mobilized in an orderly fashion when squirrel monkeys undergo whole-body exposure at the resonant frequency, 450 MHz. The threshold for alteration of thermo-regulatory behavior is about 3 mW/sq cm, equivalent to an SAR of nearly 2 W/kg. Behavioral responses serve to regulate the skin temperature at the normally preferred level. Because of the deep penetration of the radiation at resonance, this regulation results in a stable hyperthermic offset or bias in the deep body temperature. This situation is identical to that which occurs during exercise. Although not yet studied, we presume that the magnitude of this offset will be a direct function of the energy deposited in the body or SAR. Autonomic response of peripheral vasodilation and sweating, manifested on the skin surface. are stimulated at SARs similar to the behavioral threshold, indicating the possibility that such responses could serve as auxiliary sensory cues to behavior.

  17. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, Eduardo V.

    1997-01-01

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

  18. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, E.V.

    1997-11-18

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

  19. METABOLIC AND THERMOREGULATORY RESPONSES OF THE RAT MAINTAINED IN ACRYLIC OR WIRE-SCREEN CAGES: IMPLICATIONS FOR PHARMACOLOGICAL STUDIES

    EPA Science Inventory

    Laboratory rodents are usually housed and studied in cages with walls and floor made of ventilated metal or solid plastic materials. It should be recognized that a rodent's thermoregulatory requirements will vary in metal and plastic cages; and it is likely that its metabolic res...

  20. EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS. JP Nolan1, LB Wichers2, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, DL Costa1, and WP Watkinson1. 1US E...

  1. Susceptibility of the aging Brown Norway rat to carbaryl, an anti-cholinesterase-based insecticide: Thermoregulatory and cardiovascular responses.

    EPA Science Inventory

    The proportion of aged in the United States is projected to expand markedly for the next several decades. Hence, the U.S.EPA is assessing if the aged are more susceptible to environmental toxicants. The thermoregulatory and cardiovascular responses of young adult, mature adult, a...

  2. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF INSTILLED RESIDUAL OIL FLY ASH (ROFA) ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DW Winsett2, DL Costa2, and WP Watkinson2. 1UNC Sch...

  3. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS

    EPA Science Inventory


    EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, DW Winsett2, AD Ledbetter2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DC Christiani3, DL Costa2, ...

  4. EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS

    EPA Science Inventory

    EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS. JP Nolan1, LB Wichers2, J Stanek3, UP Kodavanti1, MCJ Schladweiler1, PA Evansky1, ER Lappi1, DL Costa1, and WP Watkinson1...

  5. EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS

    EPA Science Inventory


    EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS. LB Wichers1, WH Rowan2, DL Costa2, MJ Campen3 and WP Watkinson2 1UNC SPH, Chapel Hill, NC, USA; 2USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, USA; 3LRRI, A...

  6. Acute Physiological and Thermoregulatory Responses to Extended Interval Training in Endurance Runners: Influence of Athletic Performance and Age

    PubMed Central

    García-Pinillos, Felipe; Soto-Hermoso, Víctor Manuel; Latorre-Román, Pedro Ángel

    2015-01-01

    This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity. PMID:26839621

  7. Acute Physiological and Thermoregulatory Responses to Extended Interval Training in Endurance Runners: Influence of Athletic Performance and Age.

    PubMed

    García-Pinillos, Felipe; Soto-Hermoso, Víctor Manuel; Latorre-Román, Pedro Ángel

    2015-12-22

    This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity. PMID:26839621

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

    PubMed

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

    2014-04-01

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

  9. Fingered core structure of nematic boojums

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

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

  10. Repeated nitrous oxide exposure in rats causes a thermoregulatory sign-reversal with concurrent activation of opposing thermoregulatory effectors

    PubMed Central

    Ramsay, Douglas S.; Woods, Stephen C.; Kaiyala, Karl J.

    2015-01-01

    Initial administration of 60% nitrous oxide (N2O) to rats at an ambient temperature of 21°C decreases core temperature (Tc), primarily via increased heat loss (HL). Over repeated N2O administrations, rats first develop tolerance to this hypothermia and subsequently exhibit hyperthermia (a sign-reversal) due primarily to progressive increases in heat production (HP). When rats initially receive 60% N2O in a thermal gradient, they become hypothermic while selecting cooler ambient temperatures that facilitate HL. This study investigated whether rats repeatedly administered 60% N2O in a thermal gradient would use the gradient to behaviorally facilitate, or oppose, the development of chronic tolerance and a hyperthermic sign-reversal. Male Long-Evans rats (N=16) received twelve 3-h administrations of 60% N2O in a gas-tight, live-in thermal gradient. Hypothermia (Sessions 1-3), complete chronic tolerance (Sessions 4-6), and a subsequent transient hyperthermic sign-reversal (Sessions 7-12) sequentially developed. Despite the progressive recovery and eventual hyperthermic sign-reversal of Tc, rats consistently selected cooler ambient temperatures during all N2O administrations. A final 60% N2O administration in a total calorimeter indicated that the hyperthermic sign-reversal resulted primarily from increased HP. Thus, rats did not facilitate chronic tolerance development by moving to warmer locations in the gradient, and instead selected cooler ambient temperatures while simultaneously increasing autonomic HP. The inefficient concurrent activation of opposing effectors and the development of a sign-reversal are incompatible with homeostatic models of drug-adaptation and may be better interpreted using a model of drug-induced allostasis. PMID:25938127

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

    PubMed

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

    2015-02-01

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

  12. Mechanism of Hot Finger Formation in Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Matsuo, M. Y.; Tamura, Y.; Sakaguchi, H.

    2013-12-01

    Processes of mantle melting and volcanic eruptions along subduction zones are often illustrated by the use of two-dimensional cross-section models of convergent margins. However, Quaternary volcanoes in the NE Japan arc could be grouped into ten volcano clusters striking transverse to the arc; these have an average width of ~ 50 km, and are separated by parallel gaps 30-75 km wide (Tamura et al., 2002). Moreover, the structure of the mantle wedge and arc crust beneath the NE Japan arc and the Izu-Bonin-Mariana arc, respectively, suggest that the third dimension, lying along the strike of the arc, is necessary to understand the actual production of magmas in subduction zones (e.g., Nakajima et al., 2001; Hasegawa & Nakajima, 2004; Kodaira et al., 2007; Kodaira et al., 2008). Common periodic structural variations, having wavelengths of 80-100 km, can be observed in both areas. This grouping of volcanoes and the structural variations may be related to locally developed hot regions within the mantle wedge that have the form of inclined, 50 km-wide fingers (hot fingers). The 'hot fingers' models (Tamura et al., 2002) may play an important role in linking the 3D structures within the mantle wedge and overlying arc crust to volcanic eruptions at the surface. To explore a physical and mathematical mechanism to produce a hot finger pattern, we develop a hydrodynamic model of mantle convection in mantle wedge. A hypothesis incorporated in our model is a double diffusive mechanism of mantle materials; diffusion of composition of mantle materials is much weaker than temperature diffusion. We show that our model shows a spatiotemporal pattern in a mantle material composition, temperature, and velocity that are similar to the spatiotemporal patterns observed in the NE Japan arc.

  13. Possible role of vasopressin in the thermoregulatory response to chlorpyrifos in the rat.

    PubMed

    Yang, Yong-La; Gordon, Christopher J

    2002-06-01

    Arginine vasopressin is a naturally occurring antipyretic which is released into the CNS to prevent excessive elevations in body temperature during fever. Circulating levels of arginine vasopressin may also have a role in the tonic control of body temperature. We have found that the organophosphate insecticide chlorpyrifos will raise blood pressure and lower body temperature in the rat. Because arginine vasopressin is a potent hypertensive agent and is capable of lowering core temperature, we suspected that arginine vasopressin may be involved in the thermoregulatory response to chlorpyrifos. To this end, core temperature and motor activity of male and female Sprague-Dawely rats were monitored before and after treatment with the corn oil vehicle or chlorpyrifos (15 mg/kg in females; 30 mg/kg in males; oral) concomitant with injection of a saline vehicle or a type 1 arginine vasopressin antagonist (20 microg/kg in females; 30 microg/kg in males; intraperitoneally). Rats dosed with chlorpyrifos and saline underwent a 2-3 degrees reduction in core temperature >50% decrease in motor activity. The V1 antagonist attenuated the hypothermic effect of chlorpyrifos in both sexes. Chlorpyrifos-induced inhibition in motor activity was unaffected by the V1 antagonist. In another experiment, the V1 antagonist (30 microg/kg) was co-administered with saline or 0.2 mg/kg oxotremorine, a muscarinic agonist that stimulates a heat loss response and partially mimics the effects of chlorpyrifos. The V1 antagonist attenuated the hypothermic effect of oxotremorine in both sexes. Plasma arginine vasopressin levels were determined in male rats 3 hr after corn oil or 30 mg/kg chlorpyrifos. There was no significant effect of chlorpyrifos on plasma levels of arginine vasopressin. That the V1 antagonist blocked the hypothermic effect of chlorpyrifos suggests that the thermoregulatory response to chlorpyrifos is mediated by central and/or systemic vasopressin release. The lack of a significant

  14. Numerical simulation of double-diffusive finger convection

    USGS Publications Warehouse

    Hughes, J.D.; Sanford, W.E.; Vacher, H.L.

    2005-01-01

    A hybrid finite element, integrated finite difference numerical model is developed for the simulation of double-diffusive and multicomponent flow in two and three dimensions. The model is based on a multidimensional, density-dependent, saturated-unsaturated transport model (SUTRA), which uses one governing equation for fluid flow and another for solute transport. The solute-transport equation is applied sequentially to each simulated species. Density coupling of the flow and solute-transport equations is accounted for and handled using a sequential implicit Picard iterative scheme. High-resolution data from a double-diffusive Hele-Shaw experiment, initially in a density-stable configuration, is used to verify the numerical model. The temporal and spatial evolution of simulated double-diffusive convection is in good agreement with experimental results. Numerical results are very sensitive to discretization and correspond closest to experimental results when element sizes adequately define the spatial resolution of observed fingering. Numerical results also indicate that differences in the molecular diffusivity of sodium chloride and the dye used to visualize experimental sodium chloride concentrations are significant and cause inaccurate mapping of sodium chloride concentrations by the dye, especially at late times. As a result of reduced diffusion, simulated dye fingers are better defined than simulated sodium chloride fingers and exhibit more vertical mass transfer. Copyright 2005 by the American Geophysical Union.

  15. Aesthetic finger prosthesis with silicone biomaterial

    PubMed Central

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

    2013-01-01

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

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

    PubMed

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

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

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

    PubMed Central

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

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

  18. Direct impacts of climatic warming on heat stress in endothermic species: seabirds as bioindicators of changing thermoregulatory constraints.

    PubMed

    Oswald, Stephen A; Arnold, Jennifer M

    2012-06-01

    There is now abundant evidence that contemporary climatic change has indirectly affected a wide-range of species by changing trophic interactions, competition, epidemiology and habitat. However, direct physiological impacts of changing climates are rarely reported for endothermic species, despite being commonly reported for ectotherms. We review the evidence for changing physiological constraints on endothermic vertebrates at high temperatures, integrating theoretical and empirical perspectives on the morphology, physiology and behavior of marine birds. Potential for increasing heat stress exposure depends on changes in multiple environmental variables, not just air temperature, as well as organism-specific morphology, physiology and behavior. Endotherms breeding at high latitudes are vulnerable to the forecast, extensive temperature changes because of the adaptations they possess to minimize heat loss. Low-latitude species will also be challenged as they currently live close to their thermal limits and will likely suffer future water shortages. Small, highly-active species, particularly aerial foragers, are acutely vulnerable as they are least able to dissipate heat at high temperatures. Overall, direct physiological impacts of climatic change appear underrepresented in the published literature, but available data suggest they have much potential to shape behavior, morphology and distribution of endothermic species. Coincidence between future heat stress events and other energetic constraints on endotherms remains largely unexplored but will be key in determining the physiological impacts of climatic change. Multi-scale, biophysical modeling, informed by experiments that quantify thermoregulatory responses of endotherms to heat stress, is an essential precursor to urgently-needed analyses at the population or species level. PMID:22691196

  19. Temporary Interference over the Posterior Parietal Cortices Disrupts Thermoregulatory Control in Humans

    PubMed Central

    Gallace, Alberto; Soravia, Giovanna; Cattaneo, Zaira; Moseley, G. Lorimer; Vallar, Giuseppe

    2014-01-01

    The suggestion has recently been made that certain higher-order cortical areas involved in supporting multisensory representations of the body, and of the space around it, might also play a role in controlling thermoregulatory functions. Here we demonstrate that temporary interference with the function of one of these areas, the posterior parietal cortex, by repetitive transcranial magnetic stimulation, results in a decrease in limb temperature. By contrast, interference with the activity of a sensory-specific area (the primary somatosensory cortex) had no effect on temperature. The results of this experiment suggest that associative multisensory brain areas might exert a top-down modulation over basic physiological control. Such a function might be part of a larger neural circuit responsible for maintaining the integrity of the body at both a homeostatic and a psychological level. PMID:24622382

  20. Alcohol and its variable effect on human thermoregulatory response to exercise in a warm environment.

    PubMed

    Desruelle, A V; Boisvert, P; Candas, V

    1996-01-01

    The aim of this study was to observe the effect of alcohol ingestion on body temperature and local sweat rate during endogenous and exogenous heat stress. After ingesting either alcohol (1.2 g alcohol/kg of body weight) or a placebo drink, 8 subjects exercised for 60 minutes at 45% VO2max in a warm environment (35 degrees C, 45% RH). Varying patterns of response were observed in these subjects, with no consistent effect on the thermoregulatory response seen. The absence of any significant change in skin and body temperature and in sweat rate suggests that the capacity of the body to struggle against exogenous and endogenous heat is not fundamentally altered by alcohol ingestion. The difference in individual response observed in our experiment is in accord with the previous lack of clearcut effect of alcohol reported in the literature. PMID:8971501

  1. New Finger Biometric Method Using Near Infrared Imaging

    PubMed Central

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

    2011-01-01

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

  2. Effect of prewarming in the cold season on thermoregulatory responses during exercise.

    PubMed Central

    Torii, M; Yamasaki, M; Sasaki, T

    1996-01-01

    OBJECTIVE: To assess whether thermoregulation in the cold season can be affected by prewarming before exercise. METHODS: Four healthy non-athletic unacclimatised males were exercised to the same degree in summer and winter on a bicycle ergometer without prewarming (experiment 1) and after prewarming by sitting for 30 min in a room at 30 degrees C (experiment 2). During exercise, sweat production and rectal and skin temperatures were measured continuously. RESULTS: There was seasonal variation in sweating capacity and sensitivity and in heat storage during exercise without prewarming (experiment 1). After the subjects were warmed before exercise, there was no such seasonal variation in their sweat rates during exercise at 30 degrees C and 40 degrees C (experiment 2). In both cases, the sweat rate and skin temperature were dependent on the environmental temperature, and the sweat rate and core temperature were dependent on the workload. In the cold season, sweating sensitivity and evaporative cooling response could be enhanced by thermal stimulation. There was no seasonal difference in the relation between evaporative heat loss and metabolic rate in the two thermal conditions. These values did not differ significantly between winter after prewarming and summer (P > 0.05), neither did heat storage and metabolic heat production at various workloads (P > 0.05). CONCLUSIONS: There is adaptation of the thermoregulatory mechanisms during temperature acclimatisation. Body warming enhances not only the heat dissipating activity of the thermoregulatory centre but also the induction of peripheral sweat gland activity. Seasonal change of sweat rate in exercising men can be eliminated through a different type of acclimatisation by prewarming in the cold season. Images Fig. 2 PMID:8799592

  3. The Thermoregulatory Function of Thatched Nests in the South American Grass-Cutting Ant, Acromyrmex heyeri

    PubMed Central

    Bollazzi, Martin; Roces, Flavio

    2010-01-01

    The construction of mound-shaped nests by ants is considered as a behavioral adaptation to low environmental temperatures, i.e., colonies achieve higher and more stables temperatures than those of the environment. Besides the well-known nests of boreal Formica wood-ants, several species of South American leaf-cutting ants of the genus Acromyrmex construct thatched nests. Acromyrmex workers import plant fragments as building material, and arrange them so as to form a thatch covering a central chamber, where the fungus garden is located. Thus, the degree of thermoregulation attained by the fungus garden inside the thatched nest largely depends on how the thatch affects the thermal relations between the fungus and the environment. This work was aimed at studying the thermoregulatory function of the thatched nests built by the grass-cutting ant Acromyrmex heyeri Forel (Hymenoptera: Formicidae: Myrmicinae). Nest and environmental temperatures were measured as a function of solar radiation on the long-term. The thermal diffusivity of the nest thatch was measured and compared to that of the surrounding soil, in order to assess the influence of the building material on the nest's thermoregulatory ability. The results showed that the average core temperature of thatched nests was higher than that of the environment, but remained below values harmful for the fungus. This thermoregulation was brought about by the low thermal diffusivity of the nest thatch built by workers with plant fragments, instead of the readily-available soil particles that have a higher thermal diffusivity. The thatch prevented diurnal nest overheating by the incoming solar radiation, and avoided losses of the accumulated daily heat into the cold air during the night. The adaptive value of thatching behavior in Acromyrmex leaf-cutting ants occurring in the southernmost distribution range is discussed. PMID:20883129

  4. Attenuated thermoregulatory sweating and cutaneous vasodilation after 14-day bed rest in humans.

    PubMed

    Michikami, Daisaku; Kamiya, Atsunori; Fu, Qi; Iwase, Satoshi; Mano, Tadaaki; Sunagawa, Kenji

    2004-01-01

    We investigated the effect of head-down bed rest (HDBR) for 14 days on thermoregulatory sweating and cutaneous vasodilation in humans. Fluid intake was ad libitum during HDBR. We induced whole body heating by increasing skin temperature for 1 h with a water-perfused blanket through which hot water (42 degrees C) was circulated. The experimental room was air-conditioned (27 degrees C, 30-40% relative humidity). We measured skin blood flow (chest and forearm), skin temperatures (chest, upper arm, forearm, thigh, and calf), and tympanic temperature. We also measured sweat rate by the ventilated capsule method in which the skin area for measurement was drained by dry air conditioned at 27 degrees C under similar skin temperatures in both trials. We calculated cutaneous vascular conductance (CVC) from the ratio of skin blood flow to mean blood pressure. From tympanic temperature-sweat rate and -CVC relationships, we assessed the threshold temperature and sensitivity as the slope response of variables to a given change in tympanic temperature. HDBR increased the threshold temperature for sweating by 0.31 degrees C at the chest and 0.32 degrees C at the forearm, whereas it reduced sensitivity by 40% at the chest and 31% at the forearm. HDBR increased the threshold temperature for cutaneous vasodilation, whereas it decreased sensitivity. HDBR reduced plasma volume by 11%, whereas it did not change plasma osmolarity. The increase in the threshold temperature for sweating correlated with that for cutaneous vasodilation. In conclusion, HDBR attenuated thermoregulatory sweating and cutaneous vasodilation by increasing the threshold temperature and decreasing sensitivity. HDBR increased the threshold temperature for sweating and cutaneous vasodilation by similar magnitudes, whereas it decreased their sensitivity by different magnitudes. PMID:12949026

  5. Effects of exercise conditioning on thermoregulatory responses to repeated administration of chlorpyrifos.

    PubMed

    Rowsey, Pamela Johnson; Metzger, Bonnie L; Carlson, John; Gordon, Christopher J

    2003-05-01

    Little is known about the effects of physical activity (i.e., exercise training) on susceptibility to environmental toxicants. Chlorpyrifos (CHP), an organophosphate (OP) insecticide, affects thermoregulation, causing an acute period of hypothermia followed by a delayed fever. Since exercise conditioning alters the thermoregulatory responses of rodents, this study examined whether exercise training would alter the thermoregulatory response to repeated CHP administration in the female Sprague-Dawley rat. Core temperature (T(c)) and motor activity (MA) were monitored by radiotelemetry in rats housed at an ambient temperature (T(a)) of 22 degrees C. The rats either were provided with continuous access to running wheels (exercise group) or were housed in standard cages without wheels (sedentary group). The exercise group rats ran predominantly at night with an average of 7.6 km/24h. After 8 weeks the rats in both groups were gavaged daily with corn oil or 10mg/kg CHP (dissolved in corn oil) for 4 days. CHP induced an immediate hypothermic response followed by a delayed fever throughout the next day in the sedentary group rats after the first three doses of CHP. The exercise group rats showed no hypothermia after the first dose of CHP. However, they became hypothermic after the second and third doses of CHP. The exercise group rats developed a smaller daytime fever after each dose of CHP compared to the sedentary group rats. Overall, exercise training attenuated the hypothermic and febrile effects of repeated CHP. Thus, the data suggest that a sedentary lifestyle may increase the sensitivity to OP insecticides. Exercise training was also associated with a more rapid recovery of plasma cholinesterase activity. PMID:12706752

  6. Cardiovascular and thermoregulatory dysregulation over 24 h following acute heat stress in rats.

    PubMed

    Quinn, Carrie M; Audet, Gerald N; Charkoudian, Nisha; Leon, Lisa R

    2015-08-15

    The influences of severe heat stroke (HS) on cardiovascular function during recovery are incompletely understood. We hypothesized that HS would elicit a heart rate (HR) increase persisting through 24 h of recovery due to hemodynamic, thermoregulatory, and inflammatory events, necessitating tachycardia to support mean arterial pressure (MAP). Core temperature (Tc), HR, and MAP were measured via radiotelemetry in conscious male Fischer 344 rats (n = 22; 282.4 ± 3.5 g) during exposure to 37°C ambient temperature until a maximum Tc of 42.0°C, and during recovery at 20°C ambient temperature through 24 h. Rats were divided into Mild, Moderate, and Severe groups based on pathophysiology. HS rats exhibited hysteresis relative to Tc with HR higher for a given Tc during recovery compared with heating (P < 0.0001). "Reverse" hysteresis occurred in MAP with pressure during cooling lower than heating per degree Tc (P < 0.0001). Mild HS rats showed tachycardia [P < 0.01 vs. control (Con)] through 8 h of recovery, elevated MAP (P < 0.05 vs. Con) for the initial 5 h of recovery, with sustained hyperthermia (P < 0.05 vs. Con) through 24 h. Moderate HS rats showed significant tachycardia (P < 0.01 vs. Con), normal MAP (P > 0.05 vs. Con), and rebound hyperthermia from 4 to 24 h post-HS (P < 0.05 vs. Con). Severe HS rats showed tachycardia (P < 0.05 vs. Con), hypotension (P < 0.01 vs. Con), and hypothermia for 24 h (P < 0.05 vs. Con). Severe HS rats showed 14- and 12-fold increase in heart and liver inducible nitric oxide synthase expression, respectively. Hypotension and hypothermia in Severe HS rats was consistent with inducible nitric oxide synthase-mediated systemic vasodilation. These findings provide mechanistic insight into hemodynamic and thermoregulatory impairments during 24 h of HS recovery. PMID:26071550

  7. Delayed thermoregulatory changes in the immature rat following a single injection of ethanol.

    PubMed

    Spiers, D E; Fusco, L E

    1992-02-01

    Adult rats exhibit rebound hyperthermia within 24 hr following a single injection of ethanol (EtOH). Tests were conducted to determine whether similar changes in thermoregulatory ability occur in the immature rat. Animals were administered saline or EtOH (4 g/kg BW; intraperitoneally) at 2 to 3, 8 to 9, or 14 to 15 days of age. Littermates were handled or left undisturbed with the dams to serve as controls. All rats were tested at 24 or 48 hr post-treatment to measure steady-state colonic temperature (Tco), tail skin temperature and metabolic rate (MR) at both thermoneutral and cold ambient temperatures (Tas). The youngest group exhibited no delayed change in body temperature or MR at 24 or 48 hr post-treatment with EtOH. Likewise, thermoregulatory ability of rats pretreated with EtOH at 8 or 9 or 14 to 15 days of age was not significantly different from controls when tested 24 hr post-treatment at thermoneutral Ta. In contrast, Tco of EtOH-treated rats in the two older age groups was 1 degree C above control level when tested 24 hr post-treatment at cold Ta. This Tco response can be explained by differences in heat transfer to the tail and MR. No altered response to cold Ta was found at 48 hr postinjection, indicating recovery from the EtOH effect. A single injection with EtOH at 2 to 15 days of age results in a change in Tco, which is dependent on postinjection time, age, and Ta. PMID:1313662

  8. On the continuum-scale simulation of gravity-driven fingers with hysteretic Richards equation: Trucation error induced numerical artifacts

    SciTech Connect

    ELIASSI,MEHDI; GLASS JR.,ROBERT J.

    2000-03-08

    The authors consider the ability of the numerical solution of Richards equation to model gravity-driven fingers. Although gravity-driven fingers can be easily simulated using a partial downwind averaging method, they find the fingers are purely artificial, generated by the combined effects of truncation error induced oscillations and capillary hysteresis. Since Richards equation can only yield a monotonic solution for standard constitutive relations and constant flux boundary conditions, it is not the valid governing equation to model gravity-driven fingers, and therefore is also suspect for unsaturated flow in initially dry, highly nonlinear, and hysteretic media where these fingers occur. However, analysis of truncation error at the wetting front for the partial downwind method suggests the required mathematical behavior of a more comprehensive and physically based modeling approach for this region of parameter space.

  9. Finger multibiometric cryptosystems: fusion strategy and template security

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  10. EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTH AND COMPROMISED RATS

    EPA Science Inventory


    EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTHY AND COMPROMISED RATS. Watkinson, WP, Campen, MJ, Wichers, LB, Nolan, JP, Kodavanti, UP, Schladweiler, MCJ, Evansky, PA, Lappi, ER,...

  11. A Centroid Model of Species Distribution to Analyize Multi-directional Climate Change Finger Print in Avian Distribution in North America

    NASA Astrophysics Data System (ADS)

    Huang, Q.; Sauer, J.; Dubayah, R.

    2015-12-01

    Species distribution shift (or referred to as "fingerprint of climate change") as a primary mechanism to adapt climate change has been of great interest to ecologists and conservation practitioners. Recent meta-analyses have concluded that a wide range of animal and plant species are already shifting their distribution. However majority of the literature has focused on analyzing recent poleward and elevationally upward shift of species distribution. However if measured only in poleward shifts, the fingerprint of climate change will be underestimated significantly. In this study, we demonstrate a centroid model for range-wide analysis of distribution shifts using the North American Breeding Bird Survey. The centroid model is based on a hierarchical Bayesian framework which models population change within physiographic strata while accounting for several factors affecting species detectability. We used the centroid approach to examine large number of species permanent resident species in North America and evaluated the dreiction and magnitude of their shifting distribution. To examine the inferential ability of mean temperature and precipitation, we test a hypothesis based on climate velocity theory that species would be more likely to shift their distribution or would shift with greater magnitude in in regions with high climate change velocity. For species with significant shifts of distribution, we establish a precipitation model and a temperature model to explain their change of abundance at the strata level. Two models which are composed of mean and extreme climate indices respectively are also established to test the influences of changes in gradual and extreme climate trends.

  12. Finger tips detection for two handed gesture recognition

    NASA Astrophysics Data System (ADS)

    Bhuyan, M. K.; Kar, Mithun Kumar; Neog, Debanga Raj

    2011-10-01

    In this paper, a novel algorithm is proposed for fingertips detection in view of two-handed static hand pose recognition. In our method, finger tips of both hands are detected after detecting hand regions by skin color-based segmentation. At first, the face is removed in the image by using Haar classifier and subsequently, the regions corresponding to the gesturing hands are isolated by a region labeling technique. Next, the key geometric features characterizing gesturing hands are extracted for two hands. Finally, for all possible/allowable finger movements, a probabilistic model is developed for pose recognition. Proposed method can be employed in a variety of applications like sign language recognition and human-robot-interactions etc.

  13. Hand and finger skin temperatures in convective and contact cold exposure.

    PubMed

    Chen, F; Liu, Z Y; Holmér, I

    1996-01-01

    The present study aimed at investigating the spatial variability of skin temperature (Tsk) measured at various points on the hand during convective and cold contact exposure. A group of 8 subjects participated in a study of convective cooling of the hand (60 min) and 20 subjects to contact cooling of the finger pad (5 min). Experiments were carried out in a small climatic chamber into which the hand was inserted. For convective cold exposure, Tsk was measured at seven points on the palmer surface of the fingers of the left hand, one on the palmar surface and one on the dorsal surface of the hand. The air temperature inside the mini-chamber was 0, 4, 10 and 16 degrees C. With the contact cold exposure, the subjects touched at constant pressures an aluminum cube cooled to temperatures of -7, 0 and 7 degrees C in the same mini-chamber. Contact Tsk was measured on the finger pad of the index finger of the left hand. The Tsk of the proximal phalanx of the index finger (on both palm and back sides), and of the middle phalanx of the little finger was also measured. The variation of Tsk between the proximal and the distal phalanx of the index finger was between 1.5 to 10 degrees C during the convective cold exposure to an air temperature of 0 degree C. Considerable gradients persisted between the hand and fingers (from 2 to 17 degrees C at 0 degree C air temperature) and between the phalanges of the finger (from 0.5 to 11.4 degrees C at 0 degree C air temperature). The onset of cold induced vasodilatation (CIVD) on different fingers varied from about 5 to 15 min and it did not always appear in every finger. For contact cold exposure, when Tsk on the contact skin cooled down to nearly 0 degree C, the temperature at the area close to the contact skin could still be 30 degrees C. Some cases of CIVD were observed in the contact skin area, but not on other measuring points of the same finger. These results indicated that local thermal stimuli were the temperature may require

  14. Viscous fingering in miscible fluids and the oceanic asthenosphere: significance for the formation of intraplate seamount chains

    NASA Astrophysics Data System (ADS)

    Nissanka, U. S.; Weeraratne, D. S.; Parmentier, E. M.

    2014-12-01

    Recent global and regional studies of seismic tomography in both oceans and continents show linear bands of low velocity anomalies that are aligned with absolute plate motion and coincident with intraplate volcanic chains. To explain the seismic and gravity anomalies observed beneath the Pacific ocean small scale convection is frequently cited but this model does explain the wide range of wavelengths that are reported. We propose a new hypothesis suggesting that viscous fingering instabilities can form when hot and wet mantle plumes discharge into the upper mantle and displace higher viscosity depleted asthenosphere. Fingers travel laterally through the asthenospheric channel below moving plates and are correlated with melting and intraplate volcanic chains observed on the seafloor. The development of viscous fingering instabilities are investigated in laboratory fluid experiments using high viscosity miscible fluids in a Hele-Shaw cell scaled to the Earth using appropriate non-dimensional parameters. We perform a set of fluid experiments with viscosity ratios 3 to 200. Viscous fingers are observed to form for all viscosity ratios above 3.0 Pa s. After an initial growth period, fingers exhibit a constant wavelength for a given viscosity ratio. Fingering wavelength is strongly dependent on the plate spacing and therefore asthenospheric layer thickness. The average fingering wavelength is shown to increase with increasing viscosity ratio. When the viscosity ratio is high we observe longer fingers that initiate closer to the point of origin. Plate motion will be simulated using a sheet of mylar moving over radial fingers. Preliminary results indicate that fingers align with plate motion both upstream and downstream. This new model for viscous fingering may link off-axis mantle plumes to spreading centers where they contribute to melting, surface volcanism and the growth and formation of new lithosphere.

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

    PubMed Central

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Elsner, Christian; Abel, Bernd

    2014-11-01

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

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

    PubMed Central

    Elsner, Christian; Abel, Bernd

    2014-01-01

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

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

    PubMed

    Elsner, Christian; Abel, Bernd

    2014-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  20. 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

  1. Role of a decrease in body heat content in the thermoregulatory reaction of the concha auriculae vessels

    NASA Technical Reports Server (NTRS)

    Slepchuk, N. A.; Rumyantsev, G. V.

    1980-01-01

    At the constant ambient temperature 28-30 C the rabbit ear vessels were dilated and their temperature was 34.8/0.1 C. Administration of the 23-29 C water into the stomach entailed thermoregulatory construction of the ear vessels within 15-25 min. The response occurred at various combinations of temperature changes in different parts of the body. The heat content of the rabbit body, as calculated by the blood temperature in the aorta arc, reduced by 266.3 + or - 26.2 cal/kg at the beginning of the response. The decrease in the organism heat content seems to serve as a signal for occurrence of a corresponding thermoregulatory response.

  2. Perceiving fingers in single-digit arithmetic problems.

    PubMed

    Berteletti, Ilaria; Booth, James R

    2015-01-01

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

  3. Metabolic and thermoregulatory responses of the rat maintained in acrylic or wire-screen cages: implications for pharmacological studies.

    PubMed

    Gordon, C J; Fogelson, L

    1994-07-01

    Because of differences in thermal conductivity, it is likely that a rodent's thermoregulatory requirements and their response to drugs and other stimuli will vary in metal and acrylic cages. To address these issues, thermoregulatory responses were measured in rats housed in an environmental chamber with a floor made of either solid metal (aluminum) or acrylic materials (Plexiglas). Metabolic rate (M), evaporative water loss (E), thermal conductance (C), and tail skin (Tsk) and core temperature (Tc) were measured at ambient temperatures (Ta) of 10, 20, 28, 30, 32, and 34 degrees C. These thermoregulatory variables were essentially unaffected by floor type at Tas of 20 and 28 degrees C. The acrylic floor showed greater increases in M, E, Tc, and Tsk, but a smaller elevation in C as Ta increased from 28 to 34 degrees C. At a Ta of 10 degrees C, rats on the acrylic floor had a smaller M compared to that measured on the metal floor. Rats were then injected with saline or 30 mg/kg (SC) of 3,4-methylenedioxymethamphetamine (MDMA) and placed in an acrylic cage with wood chip bedding or a wire-screen cage at a Ta of 20 degrees C. The MDMA caused Tc to increase > 2.0 degrees C in rats in the acrylic cage but had no effect on Tc of rats in the wire-screen cage. The marked effect of cage type on basal thermoregulatory processes and thermogenic response to MDMA should be useful in the design and interpretation of many pharmacological studies. PMID:7916156

  4. Effect of the sympathetic nervous system co-transmitters ATP and norepinephrine on thermoregulatory response to cooling

    PubMed Central

    Kozyreva, Tamara V; Meyta, Ekaterina S; Khramova, Galina M

    2015-01-01

    The existence of co-transmitters of the sympathetic nervous system norepinephrine (NE) and ATP implies variations in the neuromodulator mechanisms of physiological processes. The role of ATP, as a transmitter of the peripheral part of sympathetic nervous system in the formation of thermoregulatory response is not clear. Whether ATP modulates any parameters of thermoregulatory response to cold; if yes, whether co-transmitters of sympathetic nervous system ATP and NE differently modulate thermoregulatory response and on which parameters of cold-defense response the influence of ATP is more pronounced. Experiments were carried out on rats. ATP (10−6), NE (10−3), and their mixture introduced iontophoretically into skin. Their effects on thermoregulatory parameters (temperature parameters, total oxygen consumption, carbon dioxide release, muscle activity, respiratory coefficient) were studied in thermoneutral conditions (without cold load) and under the cooling. In thermoneutral conditions both ATP and NE enhance total metabolism through increase in metabolic rate of lipids, NE effect being more expressed. It was shown that ATP and NE influence predominantly on the different components of the metabolic response to cold. ATP affects to the greatest extent on cold muscular thermogenesis by increasing shivering almost twofold and lowering its initiation temperature thresholds, whereas NE mainly promotes increase in non-shivering thermogenesis. When introducing the mixture of these biological substances the effect of NE is more expressed and the ATP effect is weakened. The obtained results allow to suggest that in vivo the NE effects can be more expressed when the sympathetic nervous system is stimulated by cold. Thus, NE and ATP being co-transmitters and predominantly acting on the different processes of cold thermogenesis (ATP on shivering and NE on non-shivering) may organize the certain sequence of cold defense responses.

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

    PubMed

    Ceasar, Stanislaus Antony; Ignacimuthu, Savarimuthu

    2015-01-01

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

  6. Axon reflexes in human cold exposed fingers.

    PubMed

    Daanen, H A; Ducharme, M B

    2000-02-01

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

  7. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

    PubMed Central

    2012-01-01

    Background It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. Purpose To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). Methods 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Results Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. Conclusions In comparison to the established hyper hydrating Cr

  8. OUTFLOWS FROM EVOLVED STARS: THE RAPIDLY CHANGING FINGERS OF CRL 618

    SciTech Connect

    Balick, Bruce; Huarte-Espinosa, Martin; Frank, Adam; Gomez, Thomas; Alcolea, Javier; Corradi, Romano L. M.; Vinkovic, Dejan E-mail: martinHE@pas.rochester.edu E-mail: gomezt@astro.as.utexas.edu E-mail: rcorradi@iac.es

    2013-07-20

    Our ultimate goal is to probe the nature of the collimator of the outflows in the pre-planetary nebula CRL 618. CRL 618 is uniquely suited for this purpose owing to its multiple, bright, and carefully studied finger-shaped outflows east and west of its nucleus. We compare new Hubble Space Telescope images to images in the same filters observed as much as 11 yr ago to uncover large proper motions and surface brightness changes in its multiple finger-shaped outflows. The expansion age of the ensemble of fingers is close to 100 yr. We find strong brightness variations at the fingertips during the past decade. Deep IR images reveal a multiple ring-like structure of the surrounding medium into which the outflows propagate and interact. Tightly constrained three-dimensional hydrodynamic models link the properties of the fingers to their possible formation histories. We incorporate previously published complementary information to discern whether each of the fingers of CRL 618 are the results of steady, collimated outflows or a brief ejection event that launched a set of bullets about a century ago. Finally, we argue on various physical grounds that fingers of CRL 618 are likely to be the result of a spray of clumps ejected at the nucleus of CRL 618 since any mechanism that form a sustained set of unaligned jets is unprecedented.

  9. [Breeding of robust industrial ethanol-tolerant Saccharomyces cerevisiae strain by artificial zinc finger protein library].

    PubMed

    Ma, Cui; Zhao, Xinqing; Li, Qian; Zhang, Mingming; Kim, Jin Soo; Bai, Fengwu

    2013-05-01

    Breeding of robust industrial Saccharomyces cerevisiae strains with high ethanol tolerance is of great significance for efficient fuel ethanol production. Zinc finger proteins play important roles in gene transcription and translation, and exerting control on the regulation of multiple genes. The sequence and localization of the zinc finger motif can be designed and engineered, and the artificial zinc finger protein can be used to regulate celluar metabolism. Stress tolerance of microbial strains is related to multiple genes. Therefore, it is possible to use artificially-designed zinc finger proteins to breed stress tolerant strains. In this study, a library containing artificial zinc finger protein encoding genes was transformed into the model yeast strain S288c. A recombinant strain named M01 with improved ethanol tolerance was obtained. The plasmid in M01 was isolated, and then transformed into the industrial yeast strain Sc4126. Ethanol tolerance of the recombinant strain of Sc4126 were significantly improved. When high gravity ethanol fermentation using 250 g/L glucose was performed, comparing with the wild-type strain, fermentation time of the recombinant strain was decreased by 24 h and the final ethanol concentration was enhanced by 6.3%. The results of this study demonstrate that artificial zinc finger proteins are able to exert control on stress tolerance of yeast strains, and these results provide basis to construct robust industrial yeast strains for efficient ethanol fermentation. PMID:24010359

  10. Area-preserving dynamics of a long slender finger by curvature: A test case for globally conserved phase ordering

    SciTech Connect

    Peleg, Avner; Meerson, Baruch; Vilenkin, Arkady; Conti, Massimo

    2001-06-01

    A long and slender finger can serve as a simple {open_quotes}test bed{close_quotes} for different phase-ordering models. In this work, the globally conserved, interface-controlled dynamics of a long finger is investigated, analytically and numerically, in two dimensions. An important limit is considered when the finger dynamics is reducible to area-preserving motion by curvature. A free boundary problem for the finger shape is formulated. An asymptotic perturbation theory is developed that uses the finger aspect ratio as a small parameter. The leading-order approximation is a modification of the Mullins finger (a well-known analytic solution) whose width is allowed to slowly vary with time. This time dependence is described, in the leading order, by an exponential law with the characteristic time proportional to the (constant) finger area. The subleading terms of the asymptotic theory are also calculated. Finally, the finger dynamics is investigated numerically, employing the Ginzburg-Landau equation with a global conservation law. The theory is in very good agreement with the numerical solution.

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

    PubMed

    Mishra, Satyanarayan; Manisundaram, S

    2010-04-01

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

  12. Shifts in thermoregulatory strategy during ontogeny in harp seals (Pagophilus groenlandicus).

    PubMed

    Pearson, Linnea E; Liwanag, Heather E M; Hammill, Mike O; Burns, Jennifer M

    2014-08-01

    Heat balance can be difficult for young and/or small animals in polar regions because environmental conditions in combination with small body size or physiological immaturity can increase heat loss. We investigated how thermoregulatory patterns change with ontogeny in 5 age classes of harp seal (Pagophilus groenlandicus) from birth to post-molt to further understand the timing of thermoregulatory development in relation to their potential vulnerability to ongoing fluctuations in the extent and stability of Arctic pack ice. We measured changes in the amount, conductivity, and resistance of the seal pups׳ insulative layers (blubber and fur), the potential for endogenous heat-generation by shivering (muscle enzyme activity), and nonshivering thermogenesis (NST; brown adipose tissue (BAT) uncoupling protein 1 (UCP1) expression and mitochondrial density). There was no significant difference in blubber conductivity among age classes, though the amount of blubber insulation significantly increased from birth to weaning. Pelage conductivity was low (0.12±0.01Wm(-1)°C(-1)) except in 9-day old pups (0.40±0.08Wm(-1)°C(-1)); the significantly higher conductivity may signal the beginning of the molt, and this age group may be the most vulnerable to early water entry. Citrate synthase activity significantly increased (49.68±3.26 to 75.08±3.52μmolmin(-1)gwetweight(-1)) in the muscle; however it is unlikely that increasing a single enzyme greatly impacts heat generation. BAT of younger pups contained UCP1, though expression and mitochondrial density quickly declined, and the ability of pups to produce heat via NST was lost by weaning. While total thermal resistance did not differ, neonatal and early nursing animals gained the majority of their thermal resistance from lanugo (82.5±0.03%); however, lanugo is not insulative when wet, and NST may be important to maintain euthermia and dry the coat if early immersion in water occurs. By late nursing, blubber seems sufficient

  13. Thermoregulatory Responses and Hydration Practices in Heat-Acclimatized Adolescents During Preseason High School Football

    PubMed Central

    Yeargin, Susan Walker; Casa, Douglas J.; Judelson, Daniel A.; McDermott, Brendon P.; Ganio, Matthew S.; Lee, Elaine C.; Lopez, Rebecca M.; Stearns, Rebecca L.; Anderson, Jeffrey M.; Armstrong, Lawrence E.; Kraemer, William J.; Maresh, Carl M.

    2010-01-01

    Abstract Context: Previous researchers have not investigated the thermoregulatory responses to multiple consecutive days of American football in adolescents. Objective: To examine the thermoregulatory and hydration responses of high school players during formal preseason football practices. Design: Observational study. Setting: Players practiced outdoors in late August once per day on days 1 through 5, twice per day on days 6 and 7, and once per day on days 8 through 10. Maximum wet bulb globe temperature averaged 23 ± 4°C. Patients or Other Participants: Twenty-five heat-acclimatized adolescent boys (age  =  15 ± 1 years, height  =  180 ± 8 cm, mass  =  81.4 ± 15.8 kg, body fat  =  12 ± 5%, Tanner stage  =  4 ± 1). Main Outcome Measure(s): We observed participants within and across preseason practices of football. Measures included gastrointestinal temperature (TGI), urine osmolality, sweat rate, forearm sweat composition, fluid consumption, testosterone to cortisol ratio, perceptual measures of thirst, perceptual measures of thermal sensation, a modified Environmental Symptoms Questionnaire, and knowledge questionnaires assessing the participants' understanding of heat illnesses and hydration. Results were analyzed for differences across time and were compared between younger (14–15 years, n  =  13) and older (16–17 years, n  =  12) participants. Results: Maximum daily TGI values remained less than 40°C and were correlated with maximum wet bulb globe temperature (r  =  0.59, P  =  .009). Average urine osmolality indicated that participants generally experienced minimal to moderate hypohydration before (881 ± 285 mOsmol/kg) and after (856 ± 259 mOsmol/kg) each practice as a result of replacing approximately two-thirds of their sweat losses during exercise but inadequately rehydrating between practices. Age did not affect most variables; however, sweat rate was lower in younger participants (0.6 ± 0.2

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

    PubMed Central

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

    2009-01-01

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

  15. A Study on Self-Heating and Mutual Thermal Coupling in SiGe Multi-Finger HBTs

    NASA Astrophysics Data System (ADS)

    Dwivedi, A. D. D.; D'Esposito, Rosario; Sahoo, Amit Kumar; Fregonese, Sebastien; Zimmer, Thomas

    2016-07-01

    In this paper, the self-heating and mutual thermal coupling in a state-of-the-art SiGe:C multi-finger heterojunction bipolar transistor (HBT) was investigated in static dc operation conditions. Multi-finger HBT structure was created using Sentaurus structure editor with dimensions similar to the layout of SiGe:C multi-finger HBTs in ST-Microelectronics BiCMOS55 (B55) technology (f T > 300 GHz, f max > 400 GHz) as per ST's BiCMOS55 process design kit guidelines. Three-dimensional thermal technology computer aided design (TCAD) simulations were carried out to obtain the temperature distribution in static dc operation. The lattice temperature (T Lattice) and heat flux (F Heat) distribution inside the device were studied. The impact of back-end-of-line (BEOL) layers on static thermal behavior of the state-of-the-art SiGe:C multi finger HBTs was also investigated. The temperature dependent thermal resistance of different fingers of the trench isolated SiGe multi-finger HBT was extracted without and with back-end-of-line (BEOL) effect. An electro-thermal dc compact model of self-heating and mutual thermal coupling in multi-finger HBTs was proposed and applied to compare the modeling results with the TCAD simulation results. Very good agreement was achieved between results obtained from TCAD simulation and those obtained from compact model-based simulation.

  16. Thermoregulatory responses during thermal acclimation in pigs divergently selected for residual feed intake

    NASA Astrophysics Data System (ADS)

    Campos, Paulo Henrique Reis Furtado; Noblet, Jean; Jaguelin-Peyraud, Yolande; Gilbert, Hélène; Mormède, Pierre; de Oliveira Donzele, Rita Flavia Miranda; Donzele, Juarez Lopes; Renaudeau, David

    2014-09-01

    The objective of this study was to evaluate the performance and thermoregulatory responses during acclimation to high ambient temperature (Ta) of pigs from two lines selected for high (RFI+) or low (RFI-) residual feed intake with the hypothesis that RFI- pigs producing less heat would better tolerate high Ta. Pigs (50 kg initial body weight; 17 per line among which 10 of them were catheterized) were individually housed in a climatic-controlled room where Ta was maintained at 24.2 ± 0.4 °C during 7 days and thereafter at 30.4 ± 0.7 °C during 14 days. Irrespective of Ta, RFI- pigs had lower feed intake (ADFI) and similar average daily gain (ADG) than RFI+ pigs. Whatever the line, ADFI, ADG, and feed efficiency decreased with increased Ta. Overall, the Ta increase resulted in an increase in rectal temperature (RT), skin temperature (ST), and respiratory rate (RR) within the first 24-48 h and, subsequently, in a decrease followed by stabilization. The RT decrease during acclimation occurred 24 h earlier in RFI- pigs than in RFI+. Thyroid hormones and cortisol decreased at high Ta and it was similar in both lines. Based on performance and RT, ST, and RR responses, it seems that selection for low RFI tends to ameliorate pigs' tolerance to high Ta. Nevertheless, this selection does not induce significant differences between lines in endocrine and metabolite responses during thermal stress.

  17. Thermoregulatory development and behavior of Ctenomys talarum pups during brief repeated postnatal isolation.

    PubMed

    Baldo, María Belén; Luna, Facundo; Schleich, Cristian E; Antenucci, C Daniel

    2014-03-22

    In altricial mammals, the role of the mother and siblings throughout pup's early ontogeny is critical to determine "normal" development in neonates. It has been reported that variations in parental investment during pups' development affect thermoregulatory capacity, growth patterns, brain development and behavior during lifetime, such as spatial learning and memory in adults. Ctenomys talarum (tuco-tuco) is a solitary subterranean rodent, who inhabits complex burrows and exhibits developed spatial orientation abilities. Tuco-tuco's pups display an altricial development, spending more than 80% of the time in contact with the mother. Throughout weaning period, pups display active exploratory behavior and improvements in their spatial capabilities. Then, we determined the effect of repeated brief postnatal isolations on the acquisition of physiological thermoregulation and the development of spatial learning capabilities in tuco-tuco's pups. As it occurs in wild animals, daily brief isolations (30min) did not affect the acquisition of adult's body temperature nor resting metabolic rate's development pattern. Moreover, behavioral response and adult spatial abilities of isolated pups were similar to that observed in non-isolated ones. Then, during periods of mother's absence, minor physiological and behavioral adjustments, such as shivering and postural changes, are required to keep C. talarum pups within allostasis. PMID:24667557

  18. The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper.

    PubMed

    Harris, Rebecca M B; McQuillan, Peter; Hughes, Lesley

    2015-08-01

    Behavioural thermoregulation has the potential to alleviate the short-term impacts of climate change on some small ectotherms, without the need for changes to species distributions or genetic adaptation. We illustrate this by measuring the effect of behaviour in a cool temperate species of grasshopper (Phaulacridium vittatum) over a range of spatial and temporal scales in laboratory and natural field experiments. Microhabitat selection at the site scale was tested in free-ranging grasshoppers and related to changing thermal quality over a daily period. Artificial warming experiments were then used to measure the temperature at which common thermoregulatory behaviours are initiated and the subsequent reductions in body temperature. Behavioural means such as timing of activity, choice of substrates with optimum surface temperatures, shade seeking and postural adjustments (e.g. stilting, vertical orientation) were found to be highly effective at maintaining preferred body temperature. The maximum voluntarily tolerated temperature (MVT) was determined to be 44°C±0.4°C, indicating the upper bounds of thermal flexibility in this species. Behavioural thermoregulation effectively enables small ectotherms to regulate exposure to changing environmental temperatures and utilize the spatially and temporally heterogeneous environments they occupy. Species such as the wingless grasshopper, although adapted to cool temperate conditions, are likely to be well equipped to respond successfully to coarse scale climate change. PMID:26267501

  19. Reprint of: The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper.

    PubMed

    Harris, Rebecca M B; McQuillan, Peter; Hughes, Lesley

    2015-12-01

    Behavioural thermoregulation has the potential to alleviate the short-term impacts of climate change on some small ectotherms, without the need for changes to species distributions or genetic adaptation. We illustrate this by measuring the effect of behaviour in a cool temperate species of grasshopper (Phaulacridium vittatum) over a range of spatial and temporal scales in laboratory and natural field experiments. Microhabitat selection at the site scale was tested in free-ranging grasshoppers and related to changing thermal quality over a daily period. Artificial warming experiments were then used to measure the temperature at which common thermoregulatory behaviours are initiated and the subsequent reductions in body temperature. Behavioural means such as timing of activity, choice of substrates with optimum surface temperatures, shade seeking and postural adjustments (e.g. stilting, vertical orientation) were found to be highly effective at maintaining preferred body temperature. The maximum voluntarily tolerated temperature (MVT) was determined to be 44 °C ± 0.4 °C, indicating the upper bounds of thermal flexibility in this species. Behavioural thermoregulation effectively enables small ectotherms to regulate exposure to changing environmental temperatures and utilize the spatially and temporally heterogeneous environments they occupy. Species such as the wingless grasshopper, although adapted to cool temperate conditions, are likely to be well equipped to respond successfully to coarse scale climate change. PMID:26615722

  20. Changes in ambient temperature at the onset of thermoregulatory responses in exercise-trained rats

    NASA Astrophysics Data System (ADS)

    Sugimoto, N.; Sakurada, S.; Shido, O.

    Spontaneous running in a wheel has emerged as a useful method of exercise in rodents. We investigated how exercise training with a running wheel affects ambient temperatures (Ta) at the onset of thermoregulatory responses in rats. Female rats were allowed to run freely in the wheel for 6 months. Sedentary control rats did not exercise during the same period. After the exercise training period, they were loosely restrained and Ta values at the onset of tail skin vasodilation and cold- induced thermogenesis were determined by raising or lowering Ta. Resting levels of core temperature and heat production of the exercise-trained rats were significantly higher than those of the controls. Ta values at the onset of tail skin vasodilation and cold-induced thermogenesis of the exercise-trained rats were higher than those of the controls. The results suggest that, in rats, exercise training with a running wheel elevates ambient temperatures for heat loss and heat production, which may then contribute to maintaining the core temperature at a high level.

  1. A novel thermoregulatory role for PDE10A in mouse and human adipocytes.

    PubMed

    Hankir, Mohammed K; Kranz, Mathias; Gnad, Thorsten; Weiner, Juliane; Wagner, Sally; Deuther-Conrad, Winnie; Bronisch, Felix; Steinhoff, Karen; Luthardt, Julia; Klöting, Nora; Hesse, Swen; Seibyl, John P; Sabri, Osama; Heiker, John T; Blüher, Matthias; Pfeifer, Alexander; Brust, Peter; Fenske, Wiebke K

    2016-01-01

    Phosphodiesterase type 10A (PDE10A) is highly enriched in striatum and is under evaluation as a drug target for several psychiatric/neurodegenerative diseases. Preclinical studies implicate PDE10A in the regulation of energy homeostasis, but the mechanisms remain unclear. By utilizing small-animal PET/MRI and the novel radioligand [(18)F]-AQ28A, we found marked levels of PDE10A in interscapular brown adipose tissue (BAT) of mice. Pharmacological inactivation of PDE10A with the highly selective inhibitor MP-10 recruited BAT and potentiated thermogenesis in vivo In diet-induced obese mice, chronic administration of MP-10 caused weight loss associated with increased energy expenditure, browning of white adipose tissue, and improved insulin sensitivity. Analysis of human PET data further revealed marked levels of PDE10A in the supraclavicular region where brown/beige adipocytes are clustered in adults. Finally, the inhibition of PDE10A with MP-10 stimulated thermogenic gene expression in human brown adipocytes and induced browning of human white adipocytes. Collectively, our findings highlight a novel thermoregulatory role for PDE10A in mouse and human adipocytes and promote PDE10A inhibitors as promising candidates for the treatment of obesity and diabetes. PMID:27247380

  2. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs.

    PubMed

    Richards-Zawacki, Corinne L

    2010-02-22

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host-pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found. PMID:19864287

  3. Atropine, diazepam, and physostigmine: Thermoregulatory effects in the heat-stressed rat

    SciTech Connect

    Matthew, C.B.; Hubbard, R.W.; Francesconi, R.P. )

    1989-01-01

    The authors have previously reported that administration of atropine (A) to unrestrained, sedentary, heat-stressed rats resulted in a dose dependent increase in heating rate. Additionally, we have demonstrated that the decrements in treadmill endurance and increments in heating rate of physostigmine (PH)-treated running rats can both be restored to control levels by pretreating the animals with A and diazepam (D). Our objective in the present work was to determine if the administration of D+PH to A-treated unrestrained, sedentary, heat-stressed rats could improve their thermal tolerance. The following drugs were administered singly via lateral tail vein: vehicle-control (C), A (200 ug/kg), D (500 ug/kg), and PH (200 ug/kg). After drug administration, the rats were heat-stressed until a core temperature of 42.6{degree}C was attained when they were removed to a 26{degree}C chamber. The heating rates ({degree}C/min) and tolerance times (min) of the respective groups were: C- 0.02, 235; A- 0.08, 58; A+D- 0.06, 94; and A+D+PH- 0.04, 143. Administration of D with A significantly decreased heating rate, and D+PH more than doubled the thermal tolerance of A-treated rats. Thus, the combination of A+D+PH not only restores PH- induced performance and thermoregulatory decrements of rats exercised in a moderate environment, but also reduces A- induced heat intolerance.

  4. An efficient and inexpensive method for measuring long-term thermoregulatory behavior.

    PubMed

    Sauer, Erin L; Sperry, Jinelle H; Rohr, Jason R

    2016-08-01

    Thermoregulatory ability and behavior influence organismal responses to their environment. By measuring thermal preferences, researchers can better understand the effects that temperature tolerances have on ecological and physiological responses to both biotic and abiotic stressors. However, because of funding limitations and confounders, measuring thermoregulation can often be difficult. Here, we provide an effective, affordable (~$50 USD per unit), easy to construct, and validated apparatus for measuring the long-term thermal preferences of animals. In tests, the apparatus spanned temperatures from 9.29 to 33.94°C, and we provide methods to further increase this range. Additionally, we provide simple methods to non-invasively measure animal and substrate temperatures and to prevent temperature preferences of the focal organisms from being confounded with temperature preferences of its prey and its humidity preferences. To validate the apparatus, we show that it was capable of detecting individual-level consistency and among individual-level variation in the preferred body temperatures of Southern toads (Anaxyrus terrestris) and Cuban tree frogs (Osteopilus septentrionalis) over three-weeks. Nearly every aspect of our design is adaptable to meet the needs of a multitude of study systems, including various terrestrial amphibious, and aquatic organisms. The apparatus and methods described here can be used to quantify behavioral thermal preferences, which can be critical for determining temperature tolerances across species and thus the resiliency of species to current and impending climate change. PMID:27503737

  5. The effects of different materials of protective gloves on thermoregulatory responses.

    PubMed

    Hayashi, C; Tokura, H

    1999-01-01

    The effects of two kinds of protecting gloves for pesticide spraying made of different materials on thermoregulatory responses during exercise were studied at ambient temperature of 28 degrees C and relative humidity of 60% in six healthy females, aged 19. One kind of gloves was made of polyurethane (A) and the other of Goretex (B) with cotton lining in each glove. Both kinds of gloves had almost the same volume. Main results of the experiment were summarised as follows: (1) during the exercise an increase of rectal temperature was inhibited more effectively in B than in A; (2) skin temperature of hand was significantly lower in B than in A; (3) absolute humidity and temperature inside the gloves were significantly lower during the period from the gripping bar exercise to the end of the experiment; (4) the number of contractions by the handgrip exercise performed immediately after the second turning of the screw was significantly smaller in A than in B. The findings presented suggest that the gloves made of Goretex material could reduce thermal strain during intermittent work in warm environmental conditions. PMID:10581866

  6. Thermoregulatory and Cardiovascular Consequences of a Transient Thyrotoxicosis and Recovery in Male Mice.

    PubMed

    Hoefig, Carolin S; Harder, Lisbeth; Oelkrug, Rebecca; Meusel, Moritz; Vennström, Björn; Brabant, Georg; Mittag, Jens

    2016-07-01

    Thyroid hormones play a major role in body homeostasis, regulating energy expenditure and cardiovascular function. Given that obese people or athletes might consider rapid weight loss as beneficial, voluntary intoxication with T4 preparations is a growing cause for thyrotoxicosis. However, the long-lasting effects of transient thyrotoxicosis are poorly understood. Here we examined metabolic, thermoregulatory, and cardiovascular function upon induction and recovery from a 2-week thyrotoxicosis in male C57BL/6J mice. Our results showed that T4 treatment caused tachycardia, decreased hepatic glycogen stores, and higher body temperature as expected; however, we did not observe an increase in brown fat thermogenesis or decreased tail heat loss, suggesting that these tissues do not contribute to the hyperthermia induced by thyroid hormone. Most interestingly, when the T4 treatment was ended, a pronounced bradycardia was observed in the animals, which was likely caused by a rapid decline of T3 even below baseline levels. On the molecular level, this was accompanied by an overexpression of cardiac phospholamban and Serca2a mRNA, supporting the hypothesis that the heart depends more on T3 than T4. Our findings therefore demonstrate that a transient thyrotoxicosis can have pathological effects that even persist beyond the recovery of serum T4 levels, and in particular the observed bradycardia could be of clinical relevance when treating hyperthyroid patients. PMID:27145010

  7. Fingerspell: Let Your Fingers Do the Talking

    ERIC Educational Resources Information Center

    Scarlatos, Tony; Nesterenko, Dmitri

    2004-01-01

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

  8. Fingers Make a Comeback in Math

    ERIC Educational Resources Information Center

    Brooks, Andree

    1978-01-01

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

  9. Finger arterial pressure measurement with Finapres.

    PubMed

    Wesseling, K H

    1996-01-01

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

  10. Fjord geometry observed in viscous fingering*

    NASA Astrophysics Data System (ADS)

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

    2004-11-01

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

  11. Fingering phenomena during grain-grain displacement

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  12. Compact Tactile Sensors for Robot Fingers

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  13. Sticky fingers: Adhesive properties of human fingertips.

    PubMed

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

    2016-02-29

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

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

    PubMed Central

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

    2010-01-01

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

  15. Setting tool with retractable torque fingers

    SciTech Connect

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

    1986-07-08

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

  16. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  17. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

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

    PubMed

    Zavala, Paul

    2014-01-01

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

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

    PubMed

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

    2012-01-01

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

  20. Pressure Balanced, Low Hysteresis Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  1. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  2. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

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

    PubMed

    Kinoshita, Hiroshi; Obata, Satoshi

    2009-07-01

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

  4. Tide-induced fingering flow during submarine groundwater discharge

    NASA Astrophysics Data System (ADS)

    Greskowiak, Janek

    2013-04-01

    Submarine groundwater discharge (SGD) is a relevant component of the hydrological cycle (Moore, 2010). The discharge of fresh groundwater that originated from precipitation on the land typically occurs at the near shore scale (~ 10m-100m) and the embayment scale (~ 100m - 10km) (Bratton, 2010). In the recent years a number of studies revealed that tidal forcing has an important effect on the fresh SGD pattern in the beach zone, i.e., it leads to the formation of an upper saline recirculation cell and a lower "freshwater discharge tube" (Boufadel, 2000, Robinson et al., 2007; Kuan et al., 2012). Thereby the discharge of the fresh groundwater occurs near the low-tide mark. The shape and extent of the upper saline recirculation cell is mainly defined by the tidal amplitude, beach slope, fresh groundwater discharge rate and hydraulic conductivity (Robinson et al., 2007). In spite of fact that in this case sea water overlies less denser freshwater, all previous modeling studies suggested that the saline recirculation cell and the freshwater tube are rather stable. However, new numerical investigations indicate that there maybe realistic cases where the upper saline recirculation cell becomes unstable as a result of the density contrast to the underlying freshwater tube. In these cases salt water fingers develop and move downward, thereby penetrating the freshwater tube. To the author's knowledge, the present study is the first that illustrate the possibility of density induced fingering flow during near shore SGD. A total of 240 high resolution simulations with the density dependent groundwater modelling software SEAWAT-2000 (Langevin et al., 2007) has been carried out to identify the conditions under which salt water fingering starts to occur. The simulations are based on the field-scale model setup employed in Robinson et al. (2007). The simulation results indicate that a very flat beach slope of less than 1:35, a hydraulic conductivity of 10 m/d and already a tidal

  5. Finger-powered electrophoretic transport of discrete droplets for portable digital microfluidics.

    PubMed

    Peng, Cheng; Wang, Yide; Sungtaek Ju, Y

    2016-07-01

    We report a finger-powered digital microfluidic device based on the electrophoretic transport of discrete droplets (EPD). An array of piezoelectric elements is connected in parallel to metal electrodes immersed in dielectric fluids. When deflected in a controlled sequence via human finger power, the piezoelectric elements charge and actuate droplets across each electrode pair through electrophoretic force. Successful droplet transportation requires the piezoelectric elements to provide both sufficient charge and voltage pulse duration. We quantify these requirements using numerical models to predict the electrical charges induced on the droplets and the corresponding electrophoretic forces. The models are experimentally validated by comparing the predicted and measured droplet translational velocities. We successfully demonstrated transport and merging of aqueous droplets over a range of droplet radii (0.6-0.9 mm). We further showed direct manipulation of body fluids, including droplets of saliva and urine, using our finger-powered EPD device. To facilitate practical implementation of multistep assays based on the approach, a hand/finger-rotated drum system with a programmable pattern of protrusions is designed to induce deflections of multiple piezoelectric elements and demonstrate programmable fluidic functions. An electrode-to-piezoelectric element connection scheme to minimize the number of piezoelectric elements necessary for a sequence of microfluidic functions is also explored. The present work establishes an engineering foundation to enable design and implementation of finger-powered portable EPD microfluidic devices. PMID:27292054

  6. Recovery of thumb and finger extension and its relation to grasp performance after stroke.

    PubMed

    Lang, Catherine E; DeJong, Stacey L; Beebe, Justin A

    2009-07-01

    This study investigated how the ability to extend the fingers and thumb recovers early after stroke and how the ability to extend all of the digits affects grasping performance. We studied 24 hemiparetic patients at 3 and 13 wk post stroke. At each visit, we tested the subjects' ability to actively extend all five digits of their contralesional, affected hand against gravity and to perform a grasp movement with the same hand. Three-dimensional motion analysis captured: 1) maximal voluntary extension excursion of each digit and 2) grasp performance variables of movement time, peak aperture, peak aperture rate, and aperture path ratio. We found that finger and thumb extension improved from 3 to 13 wk, with average improvements ranging from 12 to 19 degrees across the five digits. Grasp performance improved on two of the four variables measured. Peak apertures and peak aperture rates improved from 3 to 13 wk, but self-selected movement time and aperture path ratio did not. Stepwise multiple regression models showed that the majority of variance in grasp performance at 13 wk could be predicted by the ability to extend the index or middle finger at 3 wk, plus the change in the ability to extend the index finger from 3 to 13 wk. R2 values ranged from 0.55 to 0.89. Our data indicate that the amount of recovery in finger and thumb extension and grasping is small from 3 to 13 wk post stroke. In people with relatively pure motor hemiparesis, one important factor underlying deficits in hand shaping during grasping is the inability to extend the fingers and thumb. Without sufficient volitional control of finger and thumb extension, successful grasping of objects will not occur. PMID:19458140

  7. Haematopoietic malignancies caused by dysregulation of a chromatin-binding PHD finger

    SciTech Connect

    Wang, Gang G.; Song, Jikui; Wang, Zhanxin; Dormann, Holger L.; Casadio, Fabio; Li, Haitao; Luo, Jun-Li; Patel, Dinshaw J.; Allis, C. David

    2009-07-21

    Histone H3 lysine4 methylation (H3K4me) has been proposed as a critical component in regulating gene expression, epigenetic states, and cellular identities. The biological meaning of H3K4me is interpreted by conserved modules including plant homeodomain (PHD) fingers that recognize varied H3K4me states. The dysregulation of PHD fingers has been implicated in several human diseases, including cancers and immune or neurological disorders. Here we report that fusing an H3K4-trimethylation (H3K4me3)-binding PHD finger, such as the carboxy-terminal PHD finger of PHF23 or JARID1A (also known as KDM5A or RBBP2), to a common fusion partner nucleoporin-98 (NUP98) as identified in human leukaemias, generated potent oncoproteins that arrested haematopoietic differentiation and induced acute myeloid leukaemia in murine models. In these processes, a PHD finger that specifically recognizes H3K4me3/2 marks was essential for leukaemogenesis. Mutations in PHD fingers that abrogated H3K4me3 binding also abolished leukaemic transformation. NUP98-PHD fusion prevented the differentiation-associated removal of H3K4me3 at many loci encoding lineage-specific transcription factors (Hox(s), Gata3, Meis1, Eya1 and Pbx1), and enforced their active gene transcription in murine haematopoietic stem/progenitor cells. Mechanistically, NUP98-PHD fusions act as 'chromatin boundary factors', dominating over polycomb-mediated gene silencing to 'lock' developmentally critical loci into an active chromatin state (H3K4me3 with induced histone acetylation), a state that defined leukaemia stem cells. Collectively, our studies represent, to our knowledge, the first report that deregulation of the PHD finger, an 'effector' of specific histone modification, perturbs the epigenetic dynamics on developmentally critical loci, catastrophizes cellular fate decision-making, and even causes oncogenesis during mammalian development.

  8. Saffman-Taylor streamers: mutual finger interaction in spark formation.

    PubMed

    Luque, Alejandro; Brau, Fabian; Ebert, Ute

    2008-07-01

    Bunches of streamers form the early stages of sparks and lightning but theory presently concentrates on single streamers or on coarse approximations of whole breakdown trees. Here a periodic array of interacting streamer discharges in a strong homogeneous electric field is studied in density or fluid approximation in two dimensions. If the period of the streamer array is small enough, the streamers do not branch, but approach uniform translation. When the streamers are close to the branching regime, the enhanced field at the tip of the streamer is close to 2Einfinity, where Einfinity is the homogeneous field applied between the electrodes. We discuss a moving boundary approximation to the density model. This moving boundary model turns out to be essentially the same as the one for two-fluid Hele-Shaw flows. In two dimensions, this model possesses a known analytical solution. The shape of the two-dimensional interacting streamers in uniform motion obtained from the PDE simulations is actually well fitted by the analytically known "selected Saffman-Taylor finger." This finding helps to understand streamer interactions and raises new questions on the general theory of finger selection in moving boundary problems. PMID:18764034

  9. Calculation of the static forces acting on ACV bag-finger skirts

    NASA Astrophysics Data System (ADS)

    Xie, Y. N.; Hua, Y.

    A mathematical model of the geometry formation of an ACV bag-finger skirt is developed to determine skirt shape and its deflection for varying cushion pressures, and calculations for the reactions of supports of the rigid structure on the skirt at the inner and outer attachment points are obtained. The model assumption that the finger triangle of the two-dimensional bag-finger skirt turns around the inner attachment point with changing ratio of cushion pressure to bag pressure is confirmed by experiments using skirt rigs. Good agreement is found between theoretical and experimental results, and it is shown that when the cushion pressure is changing, the pressure ratio is the essential dimensionless parameter for the skirt geometry formation and its deflection, and for the forces acting on it.

  10. Zinc finger proteins and the 3D organization of chromosomes.

    PubMed

    Feinauer, Christoph J; Hofmann, Andreas; Goldt, Sebastian; Liu, Lei; Máté, Gabriell; Heermann, Dieter W

    2013-01-01

    Zinc finger domains are one of the most common structural motifs in eukaryotic cells, which employ the motif in some of their most important proteins (including TFIIIA, CTCF, and ZiF268). These DNA binding proteins contain up to 37 zinc finger domains connected by flexible linker regions. They have been shown to be important organizers of the 3D structure of chromosomes and as such are called the master weaver of the genome. Using NMR and numerical simulations, much progress has been made during the past few decades in understanding their various functions and their ways of binding to the DNA, but a large knowledge gap remains to be filled. One problem of the hitherto existing theoretical models of zinc finger protein DNA binding in this context is that they are aimed at describing specific binding. Furthermore, they exclusively focus on the microscopic details or approach the problem without considering such details at all. We present the Flexible Linker Model, which aims explicitly at describing nonspecific binding. It takes into account the most important effects of flexible linkers and allows a qualitative investigation of the effects of these linkers on the nonspecific binding affinity of zinc finger proteins to DNA. Our results indicate that the binding affinity is increased by the flexible linkers by several orders of magnitude. Moreover, they show that the binding map for proteins with more than one domain presents interesting structures, which have been neither observed nor described before, and can be interpreted to fit very well with existing theories of facilitated target location. The effect of the increased binding affinity is also in agreement with recent experiments that until now have lacked an explanation. We further explore the class of proteins with flexible linkers, which are unstructured until they bind. We have developed a methodology to characterize these flexible proteins. Employing the concept of barcodes, we propose a measure to compare

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

    NASA Astrophysics Data System (ADS)

    Shukla, Priyanka; De Wit, A.

    2016-02-01

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

  12. Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions

    NASA Astrophysics Data System (ADS)

    Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

    2014-08-01

    To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ˜30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

  13. Thermoregulatory response to wearing encapsulated protective clothing during simulated work in various thermal environments.

    PubMed

    Payne, W R; Portier, B; Fairweather, I; Zhou, S; Snow, R

    1994-06-01

    This investigation assessed the thermoregulatory impact of performing simulated tasks normally encountered during chemical accident clean-up while wearing chemical protection clothing under various representative thermal loads. A Drager 500 (D) suit was worn with a self-contained breathing apparatus (SCBA) external to the suit, while both a Trelleborg Trellchem Super Extra (T) and a James North MZ500 (J) suit required the SCBA to be worn inside the suit. The D suit was unventilated, while the T and S suits were ventilated with the subject's exhaled air. The T suit also was ventilated via a 2 L/min flow of air from the SCBA. Subjects were six firefighters. Each simulation lasted for 30 minutes and involved tasks such as drum rolling, drum carrying, walking, and hose dragging. The trials were conducted at 11.3, 17.1, and 23.8 degrees C WBGT. The overall mean peak heart rate was 128.1 +/- 2.80 breaths/min and was elicited while performing lifting tasks. Nonsignificant differences (p > 0.05) were observed for both the average heart rate and sweat rate. Mean skin temperature, mean body temperature, and temperature within the suit cavity were significantly higher when wearing the D suit compared to wearing T or J suits; differences between the T and J suits were nonsignificant. Suit type did not significantly affect rectal temperature, which also failed to exceed the American Council of Governmental Industrial Hygienists' (ACGIH) standard of 38.0 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8017293

  14. Thermoregulatory, cardiovascular, and metabolic responses to mild caloric restriction in the Brown Norway rat

    PubMed Central

    Aydin, Cenk; Gordon, Christopher J

    2013-01-01

    Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known about the regulation of CR-induced hypothermia as a function of the circadian cycle. We assessed how mild CR that resulted in a 10% reduction in body weight affected the 24 h patterns of Tc as well as heart rate (HR) and motor activity (MA) of the Brown Norway rat. Telemetered rats were allowed to feed for 20 weeks ad libitum (AL) or given a CR diet. Tc, HR, and MA of CR rats exhibited nocturnal reductions and diurnal elevations, opposite to that of AL rats. The effects of CR appeared to peak at ∼4 weeks. Metabolic rate (MR) and respiratory exchange ratio (RER) were measured overnight after 18 weeks of CR. MR and RER were elevated markedly at the time of feeding in CR rats and then declined during the night. We found that the pattern of Tc was altered with CR, characterized by elimination of high nocturnal Tc's typically observed in AL animals. In terms of mechanisms to prolong life span in CR animals, we suggest that the shift in the pattern of Tc during CR (i.e., elimination of high Tc's) may be as critical as the overall mean reduction in Tc. Future studies should address how the time of feeding may affect the thermoregulatory response in calorically restricted rats. PMID:24303105

  15. Human thermoregulatory responses during cold-water immersion after artificially-induced sunburn

    SciTech Connect

    Pandolf, K.B.; Gange, R.W.; Latzka, W.A.; Blank, I.H.; Young, A.J.; Sawka, M.N. Massachusetts General Hospital, Boston )

    1991-03-11

    Thermoregulatory responses during cold-water immersion (T{sub w} = 22C) were compared in 10 men prior to artificially-induced sunburn (CONB), as well as 24-h, and 1-wk after a 2 minimal erythemal dose of UV-B radiation (SUNB) which covered {approximately}85% of the body. After 10 min of rest in cold water, these men exercised for 50 min ({approximately}51% {dot V}O{sub 2}max). Esophageal (T{sub es}), rectal (T{sub re}), and mean skin ({bar T}{sub sk}) temperatures, mean heat flow ({bar h}{sub c}), and heart rate (HR) were measured. Venous blood samples were collected before and after immersion. The {bar T}{sub sk} was higher throughout the 60-min immersion both 24-h and 1-wk after SUNB compared to CONB. The {anti h}{sub c} was higher after 10 min resting immersion and during the first 10 min of exercise when 24-h SUNB waqs compared to CONB with the difference attributed to higher h{sub c} from the back and chest. While T{sub re} and HR did not differ between conditions, T{sub es} prior to and throughout the 60-min immersion was higher when 24-h SUNB was compared to CONB. Plasma volume increased after 1-wk SUNB compared to CONB while plasma protein was reduced. Post-exercise cortisol was greater 24-h SUNB compared to either CONB or 1-wk SUNB. In conclusion, sunburn impaired the ability of these men to vasoconstrict during cold-water immersion resulting in greater heat loss. These adverse effects were still present 1 wk after sunburn when the associated erythema had disappeared.

  16. Thermoregulatory effects of chlorpyrifos in the rat: long-term changes in cholinergic and noradrenergic sensitivity.

    PubMed

    Gordon, C J

    1994-01-01

    Subcutaneous injection of a sublethal dose of chlorpyrifos (CHLP), an organophosphate (OP) pesticide, causes long-term inhibition in cholinesterase activity (ChE) of brain, blood, and other tissues. Such prolonged inhibition in ChE should lead to marked behavioral and autonomic thermoregulatory patterns, especially in terms of altered noradrenergic and cholinergic sensitivity. To evaluate the behavioral and autonomic effects of long-term ChE inhibition, Long-Evans rats were implanted with radiotelemetry transmitters that continuously monitored core temperature (Tc), heart rate (HR), and motor activity (MA). These parameters were monitored for 7 days following a single injection of peanut oil (vehicle control) or 280 mg/kg CHLP. CHLP led to a significant reduction in Tc during the first night after treatment but had no other effects on Tc. CHLP also resulted in a significant elevation in HR which lasted for approximately 72 h. Motor activity was unaffected by CHLP. Cholinergic and noradrenergic drug sensitivity was assessed between 7 and 25 days after CHLP. CHLP-treated rats were more sensitive to norepinephrine as based on a greater hyperthermic response. MA of CHLP-treated rats was more sensitive to scopolamine. On the other hand, the hypothermic effects of oxotremorine (0.4 mg/kg) were nearly abolished by CHLP treatment, indicating tolerance to cholinergic stimulation. The tachycardic effects of methyscopolamine were also greater in the CHLP group. Overall, the acute effects of CHLP are unusual compared to other OP's in that there is no hypothermic response, an attenuated nocturnal elevation in Tc and a prolonged elevation in HR.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7514260

  17. Thermoregulatory, cardiovascular, and metabolic responses to mild caloric restriction in the Brown Norway rat.

    PubMed

    Aydin, Cenk; Gordon, Christopher J

    2013-07-01

    Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known about the regulation of CR-induced hypothermia as a function of the circadian cycle. We assessed how mild CR that resulted in a 10% reduction in body weight affected the 24 h patterns of Tc as well as heart rate (HR) and motor activity (MA) of the Brown Norway rat. Telemetered rats were allowed to feed for 20 weeks ad libitum (AL) or given a CR diet. Tc, HR, and MA of CR rats exhibited nocturnal reductions and diurnal elevations, opposite to that of AL rats. The effects of CR appeared to peak at ∼4 weeks. Metabolic rate (MR) and respiratory exchange ratio (RER) were measured overnight after 18 weeks of CR. MR and RER were elevated markedly at the time of feeding in CR rats and then declined during the night. We found that the pattern of Tc was altered with CR, characterized by elimination of high nocturnal Tc's typically observed in AL animals. In terms of mechanisms to prolong life span in CR animals, we suggest that the shift in the pattern of Tc during CR (i.e., elimination of high Tc's) may be as critical as the overall mean reduction in Tc. Future studies should address how the time of feeding may affect the thermoregulatory response in calorically restricted rats. PMID:24303105

  18. Pressure and coverage effects of sporting compression garments on cardiovascular function, thermoregulatory function, and exercise performance.

    PubMed

    MacRae, Braid A; Laing, Raechel M; Niven, Brian E; Cotter, James D

    2012-05-01

    Sporting compression garments (CG) are used widely during exercise despite little evidence of benefits. The purpose of this study was to investigate coverage and pressure effects of full-body CG on cardiovascular and thermoregulatory function at rest and during prolonged exercise, and on exercise performance. Twelve recreationally trained male cyclists [mean (SD) age, 26 (7) years; VO(2 max), 53 (8) mL kg(-1) min(-1)] completed three sessions (counterbalanced order), wearing either correctly-sized CG (CSG; 11-15 mmHg), over-sized CG (OSG; 8-13 mmHg), or gym shorts (CONT). Test sessions were conducted in temperate conditions [24 (1)°C, 60 (4)% relative humidity; ~2 m s(-1) air velocity during exercise], consisting of resting on a chair then on a cycle ergometer, before 60-min fixed-load cycling at ~65% VO(2 max) and a 6-km time trial. Wearing CG (CSG or OSG) did not mitigate cardiovascular strain during mild orthostatic stress at rest (p = 0.20-0.93 for garment effects). During exercise, cardiac output was ~5% higher in the CG conditions (p < 0.05), which appears to be accounted for via non-significant higher end-exercise heart rate (~4-7%, p = 0.30; p = 0.06 for greater heart rate drift in CSG); other cardiovascular variables, including stroke volume, were similar among conditions (p = 0.23-0.91). Covered-skin temperature was higher in CG conditions (p < 0.001) but core (oesophageal) temperature was not (p = 0.79). Time-trial performance (mean power, time taken) was similar with or without CG (p = 0.24-0.44). In conclusion, any demonstrable physiological or psychophysical effects of full-body CG were mild and seemingly reflective more of surface coverage than pressure. No benefit was evident for exercise performance. PMID:21901265

  19. Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions.

    PubMed

    Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

    2014-08-01

    To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ∼30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels. PMID:23884733

  20. Nylon-muscle-actuated robotic finger

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  1. Articular synovial chondromatosis of the finger.

    PubMed

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

    2014-10-01

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

  2. Low-Friction Joint for Robot Fingers

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.

    1985-01-01

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

  3. Vibration white finger: a follow up study.

    PubMed Central

    Ekenvall, L; Carlsson, A

    1987-01-01

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

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

    PubMed

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

    2016-01-01

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

  5. Multi-finger Prehension: An overview

    PubMed Central

    Zatsiorsky, Vladimir M.; Latash, Mark L.

    2009-01-01

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

  6. Palm to Finger Ulnar Sensory Nerve Conduction

    PubMed Central

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

    2015-01-01

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

  7. An IPMC microgripper with integrated actuator and sensing for constant finger-tip displacement

    NASA Astrophysics Data System (ADS)

    Gonzalez, Carlos; Lumia, Ron

    2015-05-01

    Ionic polymer metal composite (IPMC) is a type of smart material that has gained the interest of many researchers due to its ability to achieve large displacements under small input voltages, usually less than 2.5 V. This has motivated the use of these materials in microsystems and systems in the millimeter scale, such as microgrippers. However, few of the control techniques developed thus far have considered the feasibility of using IPMCs in closed loop systems without the need of oversized external sensors. This paper presents a control scheme for a two-finger IPMC microgripper that accomplishes constant finger-tip displacements without external sensors. This scheme generates a displacement-dependent, time varying reference signal to obtain constant finger-tip displacements applied by a separate actuated IPMC. This actuator uses a PID controller tuned with a model-free approach, and is gain scheduled to span up to 1 mm finger-tip displacements. The microgripper achieves zero steady state error for finger-tip displacements on the tuned values of the PID controller. The gain scheduled PID controller is tested and results show zero steady state error to 0.25 mm displacements, and 15 and 20% steady state error when referenced to deflection of 0.45 and 0.75 mm, respectively. This shows that there is great confidence and validity of the control scheme, especially when tracking small reference deflections.

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

  9. An overview of instability and fingering during immiscible fluid flow in porous and fractured media

    SciTech Connect

    Chen, G.; Neuman, S.P.; Taniguchi, M.

    1995-04-01

    Wetting front instability is an important phenomenon affecting fluid flow and contaminant transport in unsaturated soils and rocks. It causes the development of fingers which travel faster than would a uniform front and thus bypass much of the medium. Water saturation and solute concentration in such fingers tend to be higher than in the surrounding medium. During infiltration, fingering may cause unexpectedly rapid arrival of water and solute at the water-table. This notwithstanding, most models of subsurface flow and transport ignore instability and fingering. In this report, we survey the literature to assess the extent to which this may or may not be justified. Our overview covers experiments, theoretical studies, and computer simulations of instability and fingering during immiscible two-phase flow and transport, with emphasis on infiltration into soils and fractured rocks. Our description of instability in an ideal fracture (Hele-Shaw cell) includes an extension of existing theory to fractures and interfaces having arbitrary orientations in space. Our discussion of instability in porous media includes a slight but important correction of existing theory for the case of an inclined interface. We conclude by outlining some potential directions for future research. Among these, we single out the effect of soil and rock heterogeneities on instability and preferential flow as meriting special attention in the context of nuclear waste storage in unsaturated media.

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

    SciTech Connect

    Miyamoto, Kazuhide; Togiya, Kayo

    2010-04-16

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

  11. Two- and Three-Dimensional Numerical Experiments Representing Two Limiting Cases of an In-Line Pair of Finger Seal Components

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Steinetz, B. M.; Kudriavtsev, V. V.; Proctor, M. P.; Kiraly, L. James (Technical Monitor)

    2002-01-01

    The work presented here concerns the numerical development and simulation of the flow, pressure patterns and motion of a pair of fingers arranged behind each other and axially aligned in-line. The fingers represent the basic elemental component of a Finger Seal (FS) and form a tight seal around the rotor. Yet their flexibility allows compliance with rotor motion and in a passive-adaptive mode complies also with the hydrodynamic forces induced by the flowing fluid. While the paper does not treat the actual staggered configuration of a finger seal, the inline arrangement represents a first step towards that final goal. The numerical 2-D (axial-radial) and 3-D results presented herein were obtained using a commercial package (CFD-ACE+). Both models use an integrated numerical approach, which couples the hydrodynamic fluid model (Navier-Stokes based) to the solid mechanics code that models the compliance of the fingers.

  12. CHEMICAL TRANSPORT AND SPONTANEOUS LAYER FORMATION IN FINGERING CONVECTION IN ASTROPHYSICS

    SciTech Connect

    Brown, Justin M.; Garaud, Pascale; Stellmach, Stephan

    2013-05-01

    A region of a star that is stable to convection according to the Ledoux criterion may nevertheless undergo additional mixing if the mean molecular weight increases with radius. This process is called fingering (thermohaline) convection and may account for some of the unexplained mixing in stars such as those that have been polluted by planetary infall and those burning {sup 3}He. We propose a new model for mixing by fingering convection in the parameter regime relevant for stellar (and planetary) interiors. Our theory is based on physical principles and supported by three-dimensional direct numerical simulations. We also discuss the possibility of formation of thermocompositional staircases in fingering regions, and their role in enhancing mixing. Finally, we provide a simple algorithm to implement this theory in one-dimensional stellar codes, such as KEPLER and MESA.

  13. Adhesion force in fluids: Effects of fingering, wetting, and viscous normal stresses

    NASA Astrophysics Data System (ADS)

    Anjos, Pedro H. A.; Dias, Eduardo O.; Dias, Laércio; Miranda, José A.

    2015-01-01

    Probe-tack measurements evaluate the adhesion strength of viscous fluids confined between parallel plates. This is done by recording the adhesion force that is required to lift the upper plate, while the lower plate is kept at rest. During the lifting process, it is known that the interface separating the confined fluids is deformed, causing the emergence of intricate interfacial fingering structures. Existing meticulous experiments and intensive numerical simulations indicate that fingering formation affects the lifting force, causing a decrease in intensity. In this work, we propose an analytical model that computes the lifting adhesion force by taking into account not only the effect of interfacial fingering, but also the action of wetting and viscous normal stresses. The role played by the system's spatial confinement is also considered. We show that the incorporation of all these physical ingredients is necessary to provide a better agreement between theoretical predictions and experiments.

  14. Human Finger-Prick Induced Pluripotent Stem Cells Facilitate the Development of Stem Cell Banking

    PubMed Central

    Tan, Hong-Kee; Toh, Cheng-Xu Delon; Ma, Dongrui; Yang, Binxia; Liu, Tong Ming; Lu, Jun; Wong, Chee-Wai; Tan, Tze-Kai; Li, Hu; Syn, Christopher; Tan, Eng-Lee; Lim, Bing; Lim, Yoon-Pin; Cook, Stuart A.

    2014-01-01

    Induced pluripotent stem cells (iPSCs) derived from somatic cells of patients can be a good model for studying human diseases and for future therapeutic regenerative medicine. Current initiatives to establish human iPSC (hiPSC) banking face challenges in recruiting large numbers of donors with diverse diseased, genetic, and phenotypic representations. In this study, we describe the efficient derivation of transgene-free hiPSCs from human finger-prick blood. Finger-prick sample collection can be performed on a “do-it-yourself” basis by donors and sent to the hiPSC facility for reprogramming. We show that single-drop volumes of finger-prick samples are sufficient for performing cellular reprogramming, DNA sequencing, and blood serotyping in parallel. Our novel strategy has the potential to facilitate the development of large-scale hiPSC banking worldwide. PMID:24646489

  15. Saffman-Taylor fingering with lateral injection with applications to imbibition coarsening dynamics

    NASA Astrophysics Data System (ADS)

    Lagree, Bertrand; Zaleski, Stephane; Bondino, Igor; Josserand, Christophe; Popinet, Stephane

    2013-11-01

    We report 2D simulations of Saffman-Taylor fingering motivated by the analysis of experiments on the imbibition of porous media in square slab geometries. We use a Volume-of-Fluid (VOF) method to model a two-phase Darcy flow with a sharp interface between the two fluids. The Gerris code which allows efficient parallel computations with quad-tree mesh refinement is used. It is tested for accuracy and precision using several levels of refinement and comparing to reference simulations in the literature. A fingering pattern is observed after lateral injection of a less viscous fluid into a region filled with a more viscous one. Large fractal-like clusters are observed allowing the measurements of several scaling exponents which are compared to the known Diffusion-Limited-Aggregation (DLA) and Saffman-Taylor scalings. An interesting effect is the transition from a transient cylindrical DLA pattern to a small number then a single Saffman Taylor finger.

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

    PubMed Central

    Soechting, John F.

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Tang, Qingjun; Chen, Houlei; Cai, Jinghui

    2015-09-01

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

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

    PubMed

    Gracia-Bafalluy, Maria; Noël, Marie-Pascale

    2008-04-01

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

  19. Finger synergies during multi-finger cyclic production of moment of force

    PubMed Central

    Zhang, Wei; Zatsiorsky, Vladimir M.

    2010-01-01

    We investigated multi-finger synergies stabilizing the total moment of force and the total force when the subjects produced a quick cyclic change in the total moment of force. The seated subjects performed the task with the fingers of the dominant arm while paced by the metronome at 1.33 Hz. They were required to produce a rhythmic, sine-like change in the total pronation–supination moment of force computed with respect to the midpoint between the middle and ring fingers. The framework of the uncontrolled manifold hypothesis was used to compute indices of stabilization of the total moment and of the total force across 20 cycles. Variance of the total moment showed a cyclic pattern with peaks close to the peak rate of the moment change. Variance of the total force was maximal close to peak moment into supination. Higher magnitudes of the moment directed against the required moment direction (antagonist moment) were produced by individual fingers during supination efforts as compared to pronation efforts. Indices of multi-finger synergies showed across-trials stabilization of the total moment over the whole cycle but not of the total force. These indices were smaller during supination efforts. We conclude that the central nervous system facilitates multi-finger synergies stabilizing the total rotational action across a variety of tasks. Synergies stabilizing the total force are not seen in tasks that do not explicitly require accurate force control. Pronation efforts are performed more efficiently and with better stabilization of the action. PMID:16944107

  20. The Role of Vision in the Development of Finger-Number Interactions: Finger-Counting and Finger-Montring in Blind Children

    ERIC Educational Resources Information Center

    Crollen, Virginie; Mahe, Rachel; Collignon, Olivier; Seron, Xavier

    2011-01-01

    Previous research has suggested that the use of the fingers may play a functional role in the development of a mature counting system. However, the role of developmental vision in the elaboration of a finger numeral representation remains unexplored. In the current study, 14 congenitally blind children and 14 matched sighted controls undertook…

  1. Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

    NASA Astrophysics Data System (ADS)

    Sato, Maki; Kanikowska, Dominika; Iwase, Satoshi; Shimizu, Yuuki; Inukai, Yoko; Nishimura, Naoki; Sugenoya, Junichi

    2009-09-01

    We tested the hypothesis that encouraged water drinking according to urine output for 20 days could ameliorate impaired thermoregulatory function under microgravity conditions. Twelve healthy men, aged 24 ± 1.5 years (mean ± SE), underwent -6° head-down bed rest (HDBR) for 20 days. During bed rest, subjects were encouraged to drink the same amount of water as the 24-h urine output volume of the previous day. A heat exposure test consisting of water immersion up to the knees at 42°C for 45 min after a 10 min rest (baseline) in the sitting position was performed 2 days before the 20-day HDBR (PRE), and 2 days after the 20-day HDBR (POST). Core temperature (tympanic), skin temperature, skin blood flow and sweat rate were recorded continuously. We found that the -6° HDBR did not increase the threshold temperature for onset of sweating under the encouraged water drinking regime. We conclude that encouraged water drinking could prevent impaired thermoregulatory responses after HDBR.

  2. Oral intake of encapsulated dried ginger root powder hardly affects human thermoregulatory function, but appears to facilitate fat utilization

    NASA Astrophysics Data System (ADS)

    Miyamoto, Mayumi; Matsuzaki, Kentaro; Katakura, Masanori; Hara, Toshiko; Tanabe, Yoko; Shido, Osamu

    2015-10-01

    The present study investigated the impact of a single oral ingestion of ginger on thermoregulatory function and fat oxidation in humans. Morning and afternoon oral intake of 1.0 g dried ginger root powder did not alter rectal temperature, skin blood flow, O2 consumption, CO2 production, and thermal sensation and comfort, or induce sweating at an ambient temperature of 28 °C. Ginger ingestion had no effect on threshold temperatures for skin blood flow or thermal sweating. Serum levels of free fatty acids were significantly elevated at 120 min after ginger ingestion in both the morning and afternoon. Morning ginger intake significantly reduced respiratory exchange ratios and elevated fat oxidation by 13.5 % at 120 min after ingestion. This was not the case in the afternoon. These results suggest that the effect of a single oral ginger administration on the peripheral and central thermoregulatory function is miniscule, but does facilitate fat utilization although the timing of the administration may be relevant.

  3. Active skin perfusion and thermoregulatory response in the hand following nerve injury and repair in human upper extremities.

    PubMed

    Deng, Aidong; Liu, Dan; Gu, Chen; Gu, Xiaosong; Gu, Jianhui; Hu, Wen

    2016-01-01

    Cutaneous vasoconstriction/vasodilatation occurs in response to whole body and local cooling/heating, and the vasomotor activities play a pivotal role in thermal control of the human body. The mechanisms underlying regulation of skin blood flow involve both neurogenic and humeral/local chemical influence, contributing to the initial response to thermal stimuli and the prolonged phase of response, respectively. Previous studies have suggested the impairment of cutaneous thermal regulation after nerve injury. However, the evidence regarding how the skin perfusion and thermoregulatory response evolve after nerve injury and repair remains limited. Here we observed, by utilizing laser-Doppler perfusion imaging, baseline skin perfusion and perfusion change in response to thermal stimuli after median and ulnar nerve injury, and the results showed that baseline perfusion in autonomous skin area profoundly decreased and active rewarming after clod stress dramatically diminished before sensory recovery of the skin became detectable. In addition, baseline cutaneous perfusion was recovered as the skin regained touch sensation, and exhibited positive correlation to touch sensibility of the skin. These data indicate that both active perfusion and thermoregulatory response of the skin are markedly compromised during skin denervation and can be recovered by re-innervation. This suggests the importance of timely repair of injured nerve, especially in the practice of replantation. PMID:26529641

  4. Direct effects of incubation temperature on morphology, thermoregulatory behaviour and locomotor performance in jacky dragons (Amphibolurus muricatus).

    PubMed

    Esquerré, Damien; Keogh, J Scott; Schwanz, Lisa E

    2014-07-01

    Incubation temperature is one of the most studied factors driving phenotypic plasticity in oviparous reptiles. We examined how incubation temperature influenced hatchling morphology, thermal preference and temperature-dependent running speed in the small Australian agamid lizard Amphibolurus muricatus. Hatchlings incubated at 32 °C grew more slowly than those incubated at 25 and 28 °C during their first month after hatching, and tended to be smaller at one month. These differences were no longer significant by three months of age due to selective mortality of the smallest hatchlings. The cooler incubation treatments (25 °C and 28 °C) produced lizards that had deeper and wider heads. Hatchlings from 28 °C had cooler and more stable temperature preferences, and also had lower body temperatures during a 2-h thermoregulatory behaviour trial. Locomotor performance was enhanced at higher body temperatures, but incubation temperature had no measurable effect either independently or in interaction with body temperature. Our study demonstrates that incubation temperature has direct effects on morphology and thermoregulatory behaviour that appears to be independent of any size-dependent effects. We postulate a mechanistic link between these two effects. PMID:24956955

  5. Oral intake of encapsulated dried ginger root powder hardly affects human thermoregulatory function, but appears to facilitate fat utilization.

    PubMed

    Miyamoto, Mayumi; Matsuzaki, Kentaro; Katakura, Masanori; Hara, Toshiko; Tanabe, Yoko; Shido, Osamu

    2015-10-01

    The present study investigated the impact of a single oral ingestion of ginger on thermoregulatory function and fat oxidation in humans. Morning and afternoon oral intake of 1.0 g dried ginger root powder did not alter rectal temperature, skin blood flow, O2 consumption, CO2 production, and thermal sensation and comfort, or induce sweating at an ambient temperature of 28 °C. Ginger ingestion had no effect on threshold temperatures for skin blood flow or thermal sweating. Serum levels of free fatty acids were significantly elevated at 120 min after ginger ingestion in both the morning and afternoon. Morning ginger intake significantly reduced respiratory exchange ratios and elevated fat oxidation by 13.5 % at 120 min after ingestion. This was not the case in the afternoon. These results suggest that the effect of a single oral ginger administration on the peripheral and central thermoregulatory function is miniscule, but does facilitate fat utilization although the timing of the administration may be relevant. PMID:25875447

  6. Transgenic sickle cell trait mice do not exhibit abnormal thermoregulatory and stress responses to heat shock exposure.

    PubMed

    Chen, Yifan; Islam, Aminul

    2016-07-01

    There remains controversy over whether individuals with sickle cell trait (SCT) are vulnerable to health risks during physical activity in high temperatures. We examined thermoregulatory and stress-related responses to heat exposure in SCT and wild-type (WT) mice. No significant differences in core temperature (Tc) were observed between SCT and WT mice during heat exposure. There was no correlation between peak Tc during heat exposure and levels of hemoglobin S in SCT mice. Basal levels of circulating inflammatory and stress-related markers were not significantly different between SCT and WT mice. Although heat exposure caused significant increases in plasma interleukins 1β and 6, and 8-isoprostane in SCT and WT mice, no differences were found between SCT and WT mice with similar thermal response profiles during heat exposure. SCT mice had significantly higher expression of heat shock protein 72 in heart, liver and gastrocnemius muscle than WT mice under control and post-heat conditions. In conclusion, there is neither thermoregulatory dysfunction nor abnormal stress-related response in SCT mice exposed to moderate heat. The hemoglobin variant in mice is associated with altered tissue stress protein homeostasis. PMID:27282581

  7. Examining Age-Related Movement Representations for Sequential (Fine-Motor) Finger Movements

    ERIC Educational Resources Information Center

    Gabbard, Carl; Cacola, Priscila; Bobbio, Tatiana

    2011-01-01

    Theory suggests that imagined and executed movement planning relies on internal models for action. Using a chronometry paradigm to compare the movement duration of imagined and executed movements, we tested children aged 7-11 years and adults on their ability to perform sequential finger movements. Underscoring this tactic was our desire to gain a…

  8. Diurnal variation in thermoregulatory response to chlorpyrifos and carbaryl in the rat.

    PubMed

    Gordon, C J; Mack, C M

    2001-12-14

    Time of day of exposure is rarely considered in the study of insecticide toxicology. It would be expected that the circadian temperature rhythm (CTR) as well as the circadian rhythms of other physiological processes would affect the efficacy of anticholinesterase (antiChE) insecticides. The ability of antiChE insecticides to alter core temperature (T(c)) could be affected by time of exposure in relation to the CTR. To this end, we assessed time of exposure on the efficacy of the antiChE insecticides chlorpyrifos (CHP) and carbaryl (CAR) to alter T(c) in the rat. T(c) and motor activity (MA) were monitored by radiotelemetry. Rats were dosed orally with 0, 30, and 50 mg/kg CHP or 0, 25 and 75 mg/kg CAR at 09:00 and 15:00 h. Both insecticides caused an acute decrease followed by a delayed increase in T(c) by 24-48 h post-exposure. The temperature index (TI) (area under curve of DeltaT(c) with time) was significantly greater when CHP was given at 15:00 h as compared with 09:00 h. The maximum decrease in T(c) was similar for morning and afternoon CHP. The TI following CAR was similar for morning and afternoon exposure. CHP suppressed the 24 h MA equally when given in the morning and afternoon. CAR was more effective in reducing MA when given in the morning as compared with the afternoon. The T(c) increase measured 24 h after dosing was greater when CHP was given in the morning. Overall, time of day affected the thermoregulatory toxicity of CHP but not CAR. Another experiment showed that the hypothermic efficacy of oxotremorine, a muscarinic agonist, was greater when injected at 09:00 h as compared with 15:00 h. Hence, cholinergic stimulation is probably not the only mechanism to explain the effects of the chronotoxicogical effects of some antiChE insecticides. PMID:11718951

  9. Geochemical Methods of Inference the Thermoregulatory Strategies in Middle Triassic Marine Reptiles - A Pilot Study

    NASA Astrophysics Data System (ADS)

    Surmik, Dawid; Pelc, Andrzej

    2012-01-01

    The oxygen stable isotopes investigation to elucidate thermoregulatory strategies in Middle Triassic basal sauropterygians is currently ongoing at University of Silesia and University of Maria Curie-Skłodowska. The results of similar studies on Late Mesozoic marine reptiles indicate that some of fully aquatic reptiles like plesiosaurs or ichthyosaurs could be warm-blooded animals. Our investigation is an important part of the aim of the research project "The Marine and Terrestrial reptiles in the Middle Triassic environmental background of Southern Poland" to solve the thermoregulation issue in basal marine reptiles and show how, and when did homoiothermy evolve in Sauropterygia.. Homeothermy and gigantothermy were important physiological adaptations which allowed sauropterygian ancestors to leave the shores and conquer the open seas and oceans. Badania nad paleofizjologią kopalnych kręgowców ostatnimi laty stały się niezwykle modne. Polegają one na kompilacji danych uzyskanych wieloma komplementarnymi metodami z zakresu fizjologii (badania współczesnych form, zgodnie z zasadą aktualizmu) i geochemii izotopowej. Szczególnie interesujące stały się kwestie gospodarki termicznej u gadów kopalnych, które silnie dyskutowane są w kręgach badaczy dinozaurów (Reid, 1997; Ruben i in., 1996). Badania na izotopach stabilnych tlenu szkliwa zębowego przeprowadzone na obligatoryjnie morskich gadach okresu jurajskiego i kredowego (Bernard i in., 2010; zob. także Motani, 2010) wskazują, że ichtiozaury i plezjozaury późniejszego mezozoiku mogły być zwierzętami stałocieplnymi. Brak obecnie jednoznacznych danych dotyczących gospodarki termicznej bazalnych przedstawicieli gadów morskich z triasu, choć przyjmuje się, że te zamieszkujące nadbrzeżne i marginalne strefy mórz zwierzęta były gadami zmiennocieplnymi (pojkilotermicznymi), podobnie jak współczesny legwan morski, czy też smok z Komodo. Czy przejście z pojkilo- do homojotermii by

  10. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  11. Aging and neurodegeneration: Importance of quantifying thermoregulatory stability in a rodent model of aging

    EPA Science Inventory

    Over our lives, we are exposed to a multitude of insults including heat and cold stress, toxicants, radiation, drugs, oxidative stress, and many others. The cumulative impact of these insults may ultimately be responsible for the etiology of many diseases. Since all life processe...

  12. Prosthetic finger phalanges with lifelike skin compliance for low-force social touching interactions

    PubMed Central

    2011-01-01

    Background Prosthetic arms and hands that can be controlled by the user's electromyography (EMG) signals are emerging. Eventually, these advanced prosthetic devices will be expected to touch and be touched by other people. As realistic as they may look, the currently available prosthetic hands have physical properties that are still far from the characteristics of human skins because they are much stiffer. In this paper, different configurations of synthetic finger phalanges have been investigated for their skin compliance behaviour and have been compared with the phalanges of the human fingers and a phalanx from a commercially available prosthetic hand. Methods Handshake tests were performed to identify which areas on the human hand experience high contact forces. After these areas were determined, experiments were done on selected areas using an indenting probe to obtain the force-displacement curves. Finite element simulations were used to compare the force-displacement results of the synthetic finger phalanx designs with that of the experimental results from the human and prosthetic finger phalanges. The simulation models were used to investigate the effects of (a) varying the internal topology of the finger phalanx and (b) varying different materials for the internal and external layers. Results and Conclusions During handshake, the high magnitudes of contact forces were observed at the areas where the full grasping enclosure of the other person's hand can be achieved. From these areas, the middle phalanges of the (a) little, (b) ring, and (c) middle fingers were selected. The indentation experiments on these areas showed that a 2 N force corresponds to skin tissue displacements of more than 2 mm. The results from the simulation model show that introducing an open pocket with 2 mm height on the internal structure of synthetic finger phalanges increased the skin compliance of the silicone material to 235% and the polyurethane material to 436%, as compared to a

  13. Visualization and Quantification of Fingering Flow Using Light Transmission Method

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Roth, K.

    2007-12-01

    With the aim of studying the physical process concerning the unstable fingering phenomena in two dimensions, experiments of vertical infiltration through layered sand were carried out in the laboratory using Hele-Shaw cells. We developed a light transmission method to measure the dynamics of water saturation within flow fingers in great detail with high spatial and temporal resolution. The method was calibrated using X-ray absorption. We improved the measured light transmission with correction for scattering effects through deconvolution with a point spread function which allows us to obtain quantitative high spatial resolution measurements. After fingers had fully developed, we added a dye tracer in order to distinguish mobile and immobile water fractions. Fully developed fingers consist of a tip, a core with mobile water, and a hull with immobile water. We analyzed the dynamics of water saturation within the finger tip, along the finger core behind the tip, and within the fringe of the fingers during radial growth. Our results confirm previous findings of saturation overshoot in the finger tips and revealed a saturation minimum behind the tip as a new feature. The finger development was characterized by a gradual increase in water content within the core of the finger behind this minimum and a gradual widening of the fingers to a quasi-stable state which evolves at time scales that are orders of magnitude longer than those of fingers' evolution. In this state, a sharp separation into a core with fast convective flow and a fringe with exceedingly slow flow was detected. All observed phenomena, with the exception of saturation overshoot, could be consistently explained based on the hysteretic behavior of the soil-water characteristic.

  14. Experimental study of fingered flow through initially dry sand

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Vogel, H.-J.; Roth, K.

    2006-08-01

    Water infiltration into coarse textured dry porous media becomes instable depending on flow conditions characterized through dimensionless quantities, i.e. the Bond number and the Capillary number. Instable infiltration fronts break into flow fingers which we investigate experimentally using Hele-Shaw cells. We further developed a light transmission method to measure the dynamics of water within flow fingers in great detail with high spatial and temporal resolution. The method was calibrated using x-ray absorption and the measured light transmission was corrected for scattering effects through deconvolution with a point spread function. Additionally we applied a dye tracer to visualize the velocity field within flow fingers. We analyzed the dynamics of water within the finger tips, along the finger core behind the tip, and within the fringe of the fingers during radial growth. Our results confirm previous findings of saturation overshoot in the finger tips and revealed a saturation minimum behind the tip as a new feature. The finger development was characterized by a gradual increase in water content within the core of the finger behind this minimum and a gradual widening of the fingers to a quasi-stable state which evolves on time scales that are orders of magnitudes longer than those of fingers' evolution. In this state, a sharp separation into a core with fast convective flow and a fringe with exceedingly slow flow was detected. All observed phenomena could by consistently explained based on the hysteretic behavior of the soil- water characteristic and on the positive pressure induced at the finger tip by the high flow velocity.

  15. Fingering instabilities in Newtonian and non-Newtonian fluids

    NASA Astrophysics Data System (ADS)

    Kennedy, Kristi E.

    Fingering has been studied in different fluid systems. Viscous fingering, which is driven by a difference in viscosity between fluids, has been studied by both experiments and numerical simulations. We used a single fluid with a temperature-dependent viscosity and studied the instability for a range of inlet pressures and viscosity ratios. The spreading and fingering of a fluid drop subjected to a centrifugal force, known as spin coating, has also been studied for a range of drop volumes and rotation speeds, both for a Newtonian and a non-Newtonian fluid. Experiments on viscous fingering with a single fluid, glycerine, show that an instability occurs at the boundary separating hot and cold fluid. The results indicate that the instability is similar to that which occurs between two miscible fluids. Fingering only occurs for high enough values of the inlet pressure and viscosity ratio. The wavelength of the fingering pattern is found to be proportional to the cell width for the two smallest cell widths used. The fingering patterns seen in the simulations are very similar to the experimental patterns, although there are some quantitative differences. In particular, the wavelength of the instability is seen to depend only weakly on the cell width. The spreading of silicone oil, a Newtonian fluid, during spin coating follows the time dependence predicted theoretically, although with a shift in the scaled time variable. Once the radius of the spreading silicone oil drop becomes large enough, fingers form around the perimeter of the drop for all experimental conditions studied. The number of fingers and the growth rate of the fingers are in agreement with theoretical predictions. Fingers are also observed to form for high enough drop volumes and rotation speeds during the spinning of a non-Newtonian fluid drop, Carbopol, which possesses a yield stress. In this case the fingering is a localized effect, occuring once the stress on the drop exceeds the yield stress, rather

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

    PubMed

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

    2015-01-01

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

  17. EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS HEALTHY AND MONOCROTALINE-TREATED SPRAGUE-DAWLEY RATS

    EPA Science Inventory


    EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN HEALTHY AND MONOCROTALINE-TREATED SPRAGUE-DAWLEY RATS. LB Wichers1, JP Nolan2, DW Winsett2, UP Kodavanti2, MCJ Schladweiler2, DL Costa2, and WP ...

  18. EFFECTS OF EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON INDICES OF CARDIOPULMONARY AND THERMOREGULATORY FUNCTION IN HEALTHY AND MONOCROTALINE-TREATED SPRAGUE-DAWLEY RATS

    EPA Science Inventory


    EFFECTS OF EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON INDICES OF CARDIOPULMONARY AND THERMOREGULATORY FUNCTION IN HEALTHY AND MONOCROTALINE-TREATED SPRAGUE-DAWLEY RATS. LB Wichers1, JP Nolan2, UP Kodavanti2, MCJ Schladweiler2, DW Winsett2, DL Costa2, and WP Watkinson2....

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

    PubMed

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

    2016-05-01

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

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

    PubMed Central

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

    2011-01-01

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

  1. Stick-slip instability for viscous fingering in a gel

    NASA Astrophysics Data System (ADS)

    Puff, N.; Debrégeas, G.; di Meglio, J.-M.; Higgins, D.; Bonn, D.; Wagner, C.

    2002-05-01

    The growth dynamics of an air finger injected in a visco-elastic gel (a PVA/borax aqueous solution) is studied in a linear Hele-Shaw cell. Besides the standard Saffman-Taylor instability, we observe—with increasing finger velocities—the existence of two new regimes: (a) a stick-slip regime for which the finger tip velocity oscillates between 2 different values, producing local pinching of the finger at regular intervals; (b) a "tadpole" regime where a fracture-type propagation is observed. A scaling argument is proposed to interpret the dependence of the stick-slip frequency with the measured rheological properties of the gel.

  2. Multiple trigger fingers in a musician: a case report.

    PubMed

    Yavari, Masoud; Hassanpour, Seyed Esmail; Mosavizadeh, Seyed Mehdi

    2010-05-01

    Trigger finger is a common disease which particularly occurs in middle-aged women. We present a rare case of a male musician with six trigger fingers (five in the left hand and one in the right hand). Mostly these fingers had been used for playing the guitar. The patient had previously been treated with local steroid injections in his fingers, however no response was seen. Therefore, we performed a surgical procedure. Four weeks after surgery, the patient could play the guitar without discomfort in his hands. PMID:20433233

  3. Vibration white finger and digital systolic pressure during cooling.

    PubMed Central

    Ekenvall, L; Lindblad, L E

    1986-01-01

    A cold provocation test (measurement of finger systolic pressure during combined body and local finger cooling) was performed on 111 male patients exposed to vibration and with a typical history of cold induced white finger. A new method of calculating the test result is described--namely, digital systolic blood pressure in the cooled test finger as a percentage of the systolic pressure in the arm (DP%). The conventional way of calculating the result, the systolic pressure in the cooled test finger as a percentage of the systolic pressure in the test finger when heated to 30 degrees C, corrected for changes in systemic pressure by the use of a reference finger (FSP%), requires the measurement of the systolic pressure in a reference finger. The two ways of calculating the test results give a similar sensitivity (74% for FSP%, 79% for DP% if all histories are regarded as true) but the new method does not require pressure measurements in a reference finger. This makes the test easier to perform and the result easier to understand. PMID:3964577

  4. Numerical Simulations and an Experimental Investigation of a Finger Seal

    NASA Technical Reports Server (NTRS)

    Braun, Minel; Pierson, Hazel; Li, H.; Dong, Dingeng

    2006-01-01

    Besides sealing, the other main goal of a successful finger seal design is to exhibit appropriate compliance to outside forces. The ability of the seal to ride or float along the rotor without rubbing or excessive heating is essential to the successful operation of the seal. The compliance of the finger must only occur in the radial plane; The seal needs to be as sturdy as possible in the axial direction. The compliant finger that moves radially outward with rotor growth and motion has to be able to ride the rotor back down as the rotor diameter recovers or the rotor moves "away". Thus there is an optimum stiffness for the finger.

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

    PubMed

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

    2016-05-01

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

  6. Impact of artificial "gummy" fingers on fingerprint systems

    NASA Astrophysics Data System (ADS)

    Matsumoto, Tsutomu; Matsumoto, Hiroyuki; Yamada, Koji; Hoshino, Satoshi

    2002-04-01

    Potential threats caused by something like real fingers, which are called fake or artificial fingers, should be crucial for authentication based on fingerprint systems. Security evaluation against attacks using such artificial fingers has been rarely disclosed. Only in patent literature, measures, such as live and well detection, against fake fingers have been proposed. However, the providers of fingerprint systems usually do not mention whether or not these measures are actually implemented in emerging fingerprint systems for PCs or smart cards or portable terminals, which are expected to enhance the grade of personal authentication necessary for digital transactions. As researchers who are pursuing secure systems, we would like to discuss attacks using artificial fingers and conduct experimental research to clarify the reality. This paper reports that gummy fingers, namely artificial fingers that are easily made of cheap and readily available gelatin, were accepted by extremely high rates by 11 particular fingerprint devices with optical or capacitive sensors. We have used the molds, which we made by pressing our live fingers against them or by processing fingerprint images from prints on glass surfaces, etc. We describe how to make the molds, and then show that the gummy fingers, which are made with these molds, can fool the fingerprint devices.

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

    PubMed

    Joyce, Thomas J

    2016-05-01

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

  8. Finger-Vein Verification Based on Multi-Features Fusion

    PubMed Central

    Qin, Huafeng; Qin, Lan; Xue, Lian; He, Xiping; Yu, Chengbo; Liang, Xinyuan

    2013-01-01

    This paper presents a new scheme to improve the performance of finger-vein identification systems. Firstly, a vein pattern extraction method to extract the finger-vein shape and orientation features is proposed. Secondly, to accommodate the potential local and global variations at the same time, a region-based matching scheme is investigated by employing the Scale Invariant Feature Transform (SIFT) matching method. Finally, the finger-vein shape, orientation and SIFT features are combined to further enhance the performance. The experimental results on databases of 426 and 170 fingers demonstrate the consistent superiority of the proposed approach. PMID:24196433

  9. Running economy, not aerobic fitness, independently alters thermoregulatory responses during treadmill running

    PubMed Central

    Smoljanić, Jovana; Morris, Nathan B.; Dervis, Sheila

    2014-01-01

    We sought to determine the independent influence of running economy (RE) and aerobic fitness [maximum oxygen consumption (V̇o2max)] on thermoregulatory responses during treadmill running by conducting two studies. In study 1, seven high (HI-FIT: 61 ± 5 ml O2·kg−1·min−1) and seven low (LO-FIT: 45 ± 4 ml O2·kg−1·min−1) V̇o2max males matched for physical characteristics and RE (HI-FIT: 200 ± 21; LO-FIT: 200 ± 18 ml O2·kg−1·km−1) ran for 60 min at 1) 60%V̇o2max and 2) a fixed metabolic heat production (Hprod) of 640 W. In study 2, seven high (HI-ECO: 189 ± 15.3 ml O2·kg−1·km−1) and seven low (LO-ECO: 222 ± 10 ml O2·kg−1·km−1) RE males matched for physical characteristics and V̇o2max (HI-ECO: 60 ± 3; LO-ECO: 61 ± 7 ml O2·kg−1·min−1) ran for 60 min at a fixed 1) speed of 10.5 km/h and 2) Hprod of 640 W. Environmental conditions were 25.4 ± 0.8°C, 37 ± 12% RH. In study 1, at Hprod of 640 W, similar changes in esophageal temperature (ΔTes; HI-FIT: 0.63 ± 0.20; LO-FIT: 0.63 ± 0.22°C; P = 0.986) and whole body sweat losses (WBSL; HI-FIT: 498 ± 66; LO-FIT: 497 ± 149 g; P = 0.984) occurred despite different relative intensities (HI-FIT: 55 ± 6; LO-FIT: 39 ± 2% V̇o2max; P < 0.001). At 60% V̇o2max, ΔTes (P = 0.029) and WBSL (P = 0.003) were greater in HI-FIT (1.14 ± 0.32°C; 858 ± 130 g) compared with LO-FIT (0.73 ± 0.34°C; 609 ± 123 g), as was Hprod (HI-FIT: 12.6 ± 0.9; LO-FIT: 9.4 ± 1.0 W/kg; P < 0.001) and the evaporative heat balance requirement (Ereq; HI-FIT: 691 ± 74; LO-FIT: 523 ± 65 W; P < 0.001). Similar sweating onset ΔTes and thermosensitivities occurred between V̇o2max groups. In study 2, at 10.5 km/h, ΔTes (1.16 ± 0.31 vs. 0.78 ± 0.28°C; P = 0.017) and WBSL (835 ± 73 vs. 667 ± 139 g; P = 0.015) were greater in LO-ECO, as was Hprod (13.5 ± 0.6 vs. 11.3 ± 0.8 W/kg; P < 0.001) and Ereq (741 ± 89 vs. 532 ± 130 W; P = 0.007). At Hprod of 640 W, ΔTes (P = 0.910) and WBSL (P = 0.710) were

  10. Teleoperation of Robonaut Using Finger Tracking

    NASA Technical Reports Server (NTRS)

    Champoux, Rachel G.; Luo, Victor

    2012-01-01

    With the advent of new finger tracking systems, the idea of a more expressive and intuitive user interface is being explored and implemented. One practical application for this new kind of interface is that of teleoperating a robot. For humanoid robots, a finger tracking interface is required due to the level of complexity in a human-like hand, where a joystick isn't accurate. Moreover, for some tasks, using one's own hands allows the user to communicate their intentions more effectively than other input. The purpose of this project was to develop a natural user interface for someone to teleoperate a robot that is elsewhere. Specifically, this was designed to control Robonaut on the international space station to do tasks too dangerous and/or too trivial for human astronauts. This interface was developed by integrating and modifying 3Gear's software, which includes a library of gestures and the ability to track hands. The end result is an interface in which the user can manipulate objects in real time in the user interface. then, the information is relayed to a simulator, the stand in for Robonaut, at a slight delay.

  11. Rehabilitation for bilateral amputation of fingers

    USGS Publications Warehouse

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

    2010-01-01

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

  12. Lipid Gymnastics: Tethers and Fingers in membrane

    NASA Astrophysics Data System (ADS)

    Tayebi, Lobat; Miller, Gregory; Parikh, Atul

    2009-03-01

    A significant body of evidence now links local mesoscopic structure (e.g., shape and composition) of the cell membrane with its function; the mechanisms by which cellular membranes adopt the specific shapes remain poorly understood. Among all the different structures adopted by cellular membranes, the tubular shape is one of the most surprising one. While their formation is typically attributed to the reorganization of membrane cytoskeleton, many exceptions exist. We report the instantaneous formation of tubular membrane mesophases following the hydration under specific thermal conditions. The shapes emerge in a bimodal way where we have two distinct diameter ranges for tubes, ˜20μm and ˜1μm, namely fat fingers and narrow tethers. We study the roughening of hydrated drops of 3 lipids in 3 different spontaneous curvatures at various temp. and ionic strength to figure out the dominant effect in selection of tethers and fingers. Dynamics of the tubes are of particular interest where we observe four distinct steps of birth, coiling, uncoiling and retraction with different lifetime on different thermal condition. These dynamics appear to reflect interplay between membrane elasticity, surface adhesion, and thermal or hydrodynamic gradient.

  13. Inhibition of virus DNA replication by artificial zinc finger proteins.

    PubMed

    Sera, Takashi

    2005-02-01

    Prevention of virus infections is a major objective in agriculture and human health. One attractive approach to the prevention is inhibition of virus replication. To demonstrate this concept in vivo, an artificial zinc finger protein (AZP) targeting the replication origin of the Beet severe curly top virus (BSCTV), a model DNA virus, was created. In vitro DNA binding assays indicated that the AZP efficiently blocked binding of the viral replication protein (Rep), which initiates virus replication, to the replication origin. All of the transgenic Arabidopsis plants expressing the AZP showed phenotypes strongly resistant to virus infection, and 84% of the transgenic plants showed no symptom. Southern blot analysis demonstrated that BSCTV replication was completely suppressed in the transgenic plants. Since the mechanism of viral DNA replication is well conserved among plants and mammals, this approach could be applied not only to agricultural crop protection but also to the prevention of virus infections in humans. PMID:15681461

  14. Experimental Study of NAPL Dissolution Fingering in Two-Dimensional Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Seyedabbasi, M.; Farthing, M. W.; Imhoff, P. T.; Miller, C. T.

    2008-12-01

    Laboratory studies were conducted to evaluate the influence of heterogeneity on NAPL dissolution fingering. During a spill event heterogeneous porous media favor the formation of nonuniform NAPL saturation fields, including NAPL residual and NAPL pools, that may affect the fingering mechanism. A light transmission technique was used to measure trichloroethylene saturation fields at a 0.05-cm resolution that resulted from spills in two heterogeneous packings of a laboratory test cell. The correlation length of the permeability field transverse to be the mean water flow direction was selected to be similar to (1.0 cm) or significantly greater than (6.0 cm) the expected wavelength of dissolution fingers. As the entrapped NAPL dissolved into water, preferential NAPL dissolution patterns occurred in both experiments, with patterns strongly affected by the heterogeneities. Experimental results were used to validate the utility of a numerical simulator for capturing the growth of centimeter-scale preferential NAPL dissolution patterns. Using data from these experiments, four different methods for upscaling the mass transfer rate coefficient for NAPL dissolution were examined [Imhoff et al., 2003; Saenton and Illangasekare, 2007; Christ et al., 2006; and Basu et al., 2008]. These models were developed to account for the influence of dissolution fingering or NAPL architecture on the long-term flux of contaminants from NAPL source zones. In the packing where the correlation scale of permeability perpendicular to the mean water flow direction was 6.0 cm, greater than the scale of the dissolution fingers, all upscaling approaches predicted effluent concentrations reasonably well. When the correlation scale of the heterogeneities was smaller (1.0 cm), the models performed much poorer. These results and their implications on the applicability of the upscaling models will be discussed.

  15. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  16. Handedness and index finger movements performed on a small touchscreen.

    PubMed

    Aoki, Tomoko; Rivlis, Gil; Schieber, Marc H

    2016-02-01

    Many studies of right/left differences in motor performance related to handedness have employed tasks that use arm movements or combined arm and hand movements rather than movements of the fingers per se, the well-known exception being rhythmic finger tapping. We therefore explored four simple tasks performed on a small touchscreen with relatively isolated movements of the index finger. Each task revealed a different right/left performance asymmetry. In a step-tracking Target Task, left-handed subjects showed greater accuracy with the index finger of the dominant left hand than with the nondominant right hand. In a Center-Out Task, right-handed subjects produced trajectories with the nondominant left hand that had greater curvature than those produced with the dominant right hand. In a continuous Circle Tracking Task, slips of the nondominant left index finger showed higher jerk than slips of the dominant right index finger. And in a continuous Complex Tracking Task, the nondominant left index finger showed shorter time lags in tracking the relatively unpredictable target than the dominant right index finger. Our findings are broadly consistent with previous studies indicating left hemisphere specialization for dynamic control and predictable situations vs. right hemisphere specialization for impedance control and unpredictable situations, the specialized contributions of the two hemispheres being combined to different degrees in the right vs. left hands of right-handed vs. left-handed individuals. PMID:26683065

  17. Toward a Phonetic Representation of Hand Configuration: The Fingers

    ERIC Educational Resources Information Center

    Johnson, Robert E.; Liddell, Scott K.

    2011-01-01

    In this article we describe a componential, articulatory approach to the phonetic description of the configuration of the four fingers. Abandoning the traditional holistic, perceptual approach, we propose a system of notational devices and distinctive features for the description of the four fingers proper (index, middle, ring, and pinky).…

  18. Rediscovering Ruth Faison Shaw and Her Finger-Painting Method

    ERIC Educational Resources Information Center

    Mayer, Veronica

    2005-01-01

    Ruth Faison Shaw was an art educator who developed a nontraditional educational perspective of teaching and a different vision about children's art. As such, she is considered by some to be the initiator of finger-painting in America (The History of Art Education Timeline 1930-1939, 2002.) Shaw developed the technique of finger-painting and a…

  19. Robust Finger Vein ROI Localization Based on Flexible Segmentation

    PubMed Central

    Lu, Yu; Xie, Shan Juan; Yoon, Sook; Yang, Jucheng; Park, Dong Sun

    2013-01-01

    Finger veins have been proved to be an effective biometric for personal identification in the recent years. However, finger vein images are easily affected by influences such as image translation, orientation, scale, scattering, finger structure, complicated background, uneven illumination, and collection posture. All these factors may contribute to inaccurate region of interest (ROI) definition, and so degrade the performance of finger vein identification system. To improve this problem, in this paper, we propose a finger vein ROI localization method that has high effectiveness and robustness against the above factors. The proposed method consists of a set of steps to localize ROIs accurately, namely segmentation, orientation correction, and ROI detection. Accurate finger region segmentation and correct calculated orientation can support each other to produce higher accuracy in localizing ROIs. Extensive experiments have been performed on the finger vein image database, MMCBNU_6000, to verify the robustness of the proposed method. The proposed method shows the segmentation accuracy of 100%. Furthermore, the average processing time of the proposed method is 22 ms for an acquired image, which satisfies the criterion of a real-time finger vein identification system. PMID:24284769

  20. Population Structure and Diversity in Finger Millet (Eleusine coracana) Germplasm.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A genotypic analysis of 79 finger millet accessions (E. coracana subsp. coracana) from 11 African and 5 Asian countries, plus 14 wild E. coracana subsp. africana lines collected in Uganda and Kenya was conducted with 45 SSR markers distributed across the finger millet genome. Phylogenetic and popula...

  1. Finger vein extraction using gradient normalization and principal curvature

    NASA Astrophysics Data System (ADS)

    Choi, Joon Hwan; Song, Wonseok; Kim, Taejeong; Lee, Seung-Rae; Kim, Hee Chan

    2009-02-01

    Finger vein authentication is a personal identification technology using finger vein images acquired by infrared imaging. It is one of the newest technologies in biometrics. Its main advantage over other biometrics is the low risk of forgery or theft, due to the fact that finger veins are not normally visible to others. Extracting finger vein patterns from infrared images is the most difficult part in finger vein authentication. Uneven illumination, varying tissues and bones, and changes in the physical conditions and the blood flow make the thickness and brightness of the same vein different in each acquisition. Accordingly, extracting finger veins at their accurate positions regardless of their thickness and brightness is necessary for accurate personal identification. For this purpose, we propose a new finger vein extraction method which is composed of gradient normalization, principal curvature calculation, and binarization. As local brightness variation has little effect on the curvature and as gradient normalization makes the curvature fairly uniform at vein pixels, our method effectively extracts finger vein patterns regardless of the vein thickness or brightness. In our experiment, the proposed method showed notable improvement as compared with the existing methods.

  2. Coordination of bowing and fingering in violin playing.

    PubMed

    Baader, Andreas P; Kazennikov, Oleg; Wiesendanger, Mario

    2005-05-01

    Playing string instruments implies motor skills including asymmetrical interlimb coordination. How special is musical skill as compared to other bimanually coordinated, non-musical skillful performances? We succeeded for the first time to measure quantitatively bimanual coordination in violinists playing repeatedly a simple tone sequence. A motion analysis system was used to record finger and bow trajectories for assessing the temporal structure of finger-press, finger-lift (left hand), and bow stroke reversals (right arm). The main results were: (1) fingering consisted of serial and parallel (anticipatory) mechanisms; (2) synchronization between finger and bow actions varied from -12 ms to 60 ms, but these 'errors' were not perceived. The results suggest that (1) bow-finger synchronization varied by about 50 ms from perfect simultaneity, but without impairing auditory perception; (2) the temporal structure depends on a number of combinatorial mechanisms of bowing and fingering. These basic mechanisms were observed in all players, including all amateurs. The successful biomechanical measures of fingering and bowing open a vast practical field of assessing motor skills. Thus, objective assessment of larger groups of string players with varying musical proficiency, or of professional string players developing movement disorders, may be helpful in music education. PMID:15820650

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

    PubMed

    Schmidt, B; Weinberg, A; Friedrich, H

    2008-06-01

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

  4. Sexual selection mediated by the thermoregulatory effects of male colour pattern in the ambush bug Phymata americana

    PubMed Central

    Punzalan, David; Rodd, F. Helen; Rowe, Locke

    2007-01-01

    Sexual dimorphism in coloration is a taxonomically widespread phenomenon often attributed to sexual selection on visual signals. However, the ambush bug Phymata americana exhibits sexual dimorphism in coloration that has no apparent signalling function. Here we provide evidence that colour pattern in this species influences male mating success indirectly through its effect on thermoregulation. We demonstrate, using experimental manipulation, that individuals with dark colour pattern achieve higher thoracic temperatures under illumination. We also show that dark colour pattern predicted mate-searching success but only under thermally challenging conditions (i.e. cool ambient temperature). As far as we are aware, this is the first study to provide evidence that sexual dimorphism can be accounted for by sexual selection on thermoregulatory performance. PMID:18089533

  5. Changes in ambient temperature differentially alter the thermoregulatory, cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone)*

    PubMed Central

    Miller, M. L.; Creehan, K.M.; Angrish, D.; Barlow, D. J.; Houseknecht, K. L.; Dickerson, T. J.; Taffe, M. A.

    2012-01-01

    BACKGROUND The substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic. METHODS Male Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0–5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20°C) and high (30°C) ambient temperature. A pharmacokinetic study found a Tmax of 0.25 h and a Cmax of 1,206 ng/mL after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20°C but there was no temperature change at 30°C. RESULTS Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30°C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20°C, and was slower in the 30°C vs. 20°C condition across all treatments. CONCLUSION These results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA. PMID:22832282

  6. A new algorithmic approach for fingers detection and identification

    NASA Astrophysics Data System (ADS)

    Mubashar Khan, Arslan; Umar, Waqas; Choudhary, Taimoor; Hussain, Fawad; Haroon Yousaf, Muhammad

    2013-03-01

    Gesture recognition is concerned with the goal of interpreting human gestures through mathematical algorithms. Gestures can originate from any bodily motion or state but commonly originate from the face or hand. Hand gesture detection in a real time environment, where the time and memory are important issues, is a critical operation. Hand gesture recognition largely depends on the accurate detection of the fingers. This paper presents a new algorithmic approach to detect and identify fingers of human hand. The proposed algorithm does not depend upon the prior knowledge of the scene. It detects the active fingers and Metacarpophalangeal (MCP) of the inactive fingers from an already detected hand. Dynamic thresholding technique and connected component labeling scheme are employed for background elimination and hand detection respectively. Algorithm proposed a new approach for finger identification in real time environment keeping the memory and time constraint as low as possible.

  7. Individuality of movements in music--finger and body movements during playing of the flute.

    PubMed

    Albrecht, Stefan; Janssen, Daniel; Quarz, Esther; Newell, Karl M; Schöllhorn, Wolfgang I

    2014-06-01

    The achievement of mastery in playing a composition by means of a musical instrument typically requires numerous repetitions and corrections according to the keys and notations of the music piece. Nevertheless, differences in the interpretation of the same music piece by highly skilled musicians seem to be recognizable. The present study investigated differences within and between skilled flute players in their finger and body movements playing the same piece several times on the same and on different days. Six semiprofessional and four professional musicians played an excerpt of Mozart's Flute Concerto No. 2 several times on three different days. Finger and body movements were recorded by 3D motion capture and analyzed by linear and nonlinear classification approaches. The findings showed that the discrete and continuous movement timing data correctly identified individuals up to 100% by means of their finger movements and up to 94% by means of their body movements. These robust examples of identifying individual movement patterns contradict the prevailing models of small, economic finger movements that are favored in the didactic literature for woodwind players and question traditional recommendations for teaching the learning of motor skills. PMID:24767961

  8. Viscous fingering in two dimensional porous layer under g-jitter

    NASA Astrophysics Data System (ADS)

    Ghosh, Pradyumna

    2012-07-01

    Slow fluid-fluid displacement in a porous medium under the influence of real microgravity field is going to reveal important fluid physics associated with hydrology, chemical engineering and the physics of disordered media. Most systems of practical importance include fluids of different densities. Therefore it is important to study the effect of g-jitter (perturbed broadband type residual acceleration due to spacecraft vibration etc.) on the front/displacement-structure (fingering: due to the nonlinear interactions among viscous, capillary and gravitational forces). CFD (Computational Fluid Dynamics) analysis glycerin/water mixture through two dimensional single layer anisotropic artificial porous layer have been performed in ground level condition as well as g-jitter condition modifying the body force source term in the momentum equation through UDF (user defined functions) written in C. Ground level experiment to capture fingering has also been performed to validate the CFD results. Fingering structures in the microgravity condition have been predicted using the validated CFD model. Keywords: CFD, g-jitter, Fingering, Nonlinear Interactions, User defined functions

  9. Paced finger-tapping abnormalities in bipolar disorder indicate timing dysfunction

    PubMed Central

    Bolbecker, Amanda R; Hong, S Lee; Kent, Jerillyn S; Forsyth, Jennifer K; Klaunig, Mallory J; Lazar, Emily; O’Donnell, Brian F; Hetrick, William P

    2011-01-01

    Background Theoretical and empirical evidence suggests that impaired time perception and the neural circuitry contributing to internal timing mechanisms may contribute to severe psychiatric disorders, including mood disorders. The structures that are involved in subsecond timing, i.e., cerebellum and basal ganglia, have also been implicated in the pathophysiology of bipolar disorder. However, the timing of subsecond intervals has infrequently been studied in this population. Methods Paced finger-tapping tasks have been used to characterize internal timing processes in neuropsychiatric disorders. A total of 42 bipolar disorder patients (25 euthymic, 17 manic) and 42 age-matched healthy controls completed a finger-tapping task in which they tapped in time with a paced (500-ms intertap interval) auditory stimulus (synchronization), then continued tapping without auditory input while attempting to maintain the same pace (continuation). This procedure was followed using the dominant index finger, then with alternating thumbs. Results Bipolar disorder participants showed greater timing variability relative to controls regardless of pacing stimulus (synchronization versus continuation) or condition (dominant index finger versus alternating thumbs). Decomposition of timing variance into internal clock versus motor implementation components using the Wing–Kristofferson model showed higher clock variability in the bipolar disorder groups compared to controls, with no differences between groups on motor implementation variability. Conclusion These findings suggest that internal timing mechanisms are disrupted in bipolar disorder patients, independent of symptom status. Increased clock variability in bipolar disorder may be related to abnormalities in cerebellar function. PMID:21320257

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

    PubMed

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

    2007-06-01

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

  11. Evaluation and application of modularly assembled zinc-finger nucleases in zebrafish

    PubMed Central

    Zhu, Cong; Smith, Tom; McNulty, Joseph; Rayla, Amy L.; Lakshmanan, Abirami; Siekmann, Arndt F.; Buffardi, Matthew; Meng, Xiangdong; Shin, Jimann; Padmanabhan, Arun; Cifuentes, Daniel; Giraldez, Antonio J.; Look, A. Thomas; Epstein, Jonathan A.; Lawson, Nathan D.; Wolfe, Scot A.

    2011-01-01

    Zinc-finger nucleases (ZFNs) allow targeted gene inactivation in a wide range of model organisms. However, construction of target-specific ZFNs is technically challenging. Here, we evaluate a straightforward modular assembly-based approach for ZFN construction and gene inactivation in zebrafish. From an archive of 27 different zinc-finger modules, we assembled more than 70 different zinc-finger cassettes and evaluated their specificity using a bacterial one-hybrid assay. In parallel, we constructed ZFNs from these cassettes and tested their ability to induce lesions in zebrafish embryos. We found that the majority of zinc-finger proteins assembled from these modules have favorable specificities and nearly one-third of modular ZFNs generated lesions at their targets in the zebrafish genome. To facilitate the application of ZFNs within the zebrafish community we constructed a public database of sites in the zebrafish genome that can be targeted using this archive. Importantly, we generated new germline mutations in eight different genes, confirming that this is a viable platform for heritable gene inactivation in vertebrates. Characterization of one of these mutants, gata2a, revealed an unexpected role for this transcription factor in vascular development. This work provides a resource to allow targeted germline gene inactivation in zebrafish and highlights the benefit of a definitive reverse genetic strategy to reveal gene function. PMID:21937602

  12. Bulk elastic fingering in soft materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Bouchaud, Elisabeth; Mahadevan, L.; Harvard University Team; Ec2M/Espci Collaboration; Cambridge University Collaboration

    2014-11-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. A systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. A very important feature is that elasticity doesn't influence this lengthscale, making this instability very generic. We will also show some new results about an elastic counterpart experiment of the famous Saffman-Taylor experiment, where we push a soft gel in a stiff one.

  13. Task specificity of finger dexterity tests.

    PubMed

    Berger, Monique A M; Krul, Arno J; Daanen, Hein A M

    2009-01-01

    Finger dexterity tests are generally used to assess performance decrease due to gloves, cold and pathology. It is generally assumed that the O'Connor and Purdue Pegboard test yield similar results. In this experiment we compared these two tests for dry conditions without gloves, and for dry and wet conditions with two types of Nytril gloves. In line with previous observations, wearing gloves caused a decrease in performance of about 12% for the O'Connor test and 9% for the Purdue test. Wetting the gloves prior to the test had no effect on the Purdue score. However, wetting the gloves increased the O'Connor performance significantly by 11%. The results show that the O'Connor and Purdue tests do not yield similar results and should be used selectively for specific tasks. PMID:18339353

  14. Bulk Elastic Fingering in Soft Materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Mora, Serge; Mahadevan, L.; Bouchaud, Elisabeth; Harvard University Team; Espci-Paristech Collaboration; Cambridge University Collaboration; Montpellier 2 University Collaboration

    2015-03-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. A systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. A very important feature is that elasticity doesn't influence this lengthscale, making this instability very generic. We will also show some new results about an elastic counterpart experiment of the famous Saffman-Taylor experiment, where we push a soft gel in a stiff one.

  15. Load-pull measurement analysis of AlGaN/GaN HEMT taking into account number of gate fingers

    NASA Astrophysics Data System (ADS)

    Tiwat, Pongthavornkamol; Guoguo, Liu; Tingting, Yuan; Yingkui, Zheng; Xinyu, Liu

    2016-06-01

    This paper investigates load-pull measurement of AlGaN/GaN high electron mobility transistors (HEMTs) at different numbers of gate fingers. Scalable small-signal models are extracted to analyze the relationship between each model's parameters and the number of device's gate fingers. The simulated S-parameters from the small-signal models are compared with the reflection coefficients measured from the load-pull measurement system at X-band frequencies of 8.8 and 10.4 GHz. The dependency between the number of device's gate fingers and load-pull characterization is presented. Project supported by the National Natural Science Foundation of China (No. 61204086).

  16. Finger movements and fingers postures in pre-term infants are not a good indicator of brain damage.

    PubMed

    Konishi, Y; Prechtl, H F

    1994-02-01

    The aim of the study was to analyse, with a more detailed classification the occurrence of movements and postures of the fingers in normal and brain damaged pre-term infants. To this end the same videorecordings of normal subjects of the study described by Cioni and Prechtl and those with defined brain lesions from the investigation by Ferrari et al. have been reanalysed. In three general movements, selected randomly from each infant, we assessed the finger movement. There was no systematic trend with age and the repertoire of finger patterns per observation varied between different individuals. Only one or two finger(s) move (pattern B) and synchronized finger opening-closing (pattern D) and the complex and variable movement of three or more fingers (pattern E) are all more often or even only seen during arm movements. Fisting without arm movement (pattern A-) was only seen less frequently in the control cases, in the infants with flares and one-sided lesions. On the other hand, the two latter groups had more often pattern C+ (opening of all fingers with arm movement) while B+ (only one or two fingers move with arm movement) and E+ (three or more fingers move variably with arm movement) was less frequent in the severely damaged infants. Albeit significant differences, the plotted data immediately show the large overlap of the findings between the groups. There was no difference in the fisting between low-risk and neurologically abnormal pre-term infants. These findings corroborate the conclusions that abnormal movements and postures are not useful in the diagnosis of pre-term infants with confirmed brain lesions because of the wide overlap between the values for normal and brain damaged infants. PMID:8200324

  17. Evaluation of a disinfectant wipe intervention on fomite-to-finger microbial transfer.

    PubMed

    Lopez, Gerardo U; Kitajima, Masaaki; Havas, Aaron; Gerba, Charles P; Reynolds, Kelly A

    2014-05-01

    Inanimate surfaces, or fomites, can serve as routes of transmission of enteric and respiratory pathogens. No previous studies have evaluated the impact of surface disinfection on the level of pathogen transfer from fomites to fingers. Thus, the present study investigated the change in microbial transfer from contaminated fomites to fingers following disinfecting wipe use. Escherichia coli (10(8) to 10(9) CFU/ml), Staphylococcus aureus (10(9) CFU/ml), Bacillus thuringiensis spores (10(7) to 10(8) CFU/ml), and poliovirus 1 (10(8) PFU/ml) were seeded on ceramic tile, laminate, and granite in 10-μl drops and allowed to dry for 30 min at a relative humidity of 15 to 32%. The seeded fomites were treated with a disinfectant wipe and allowed to dry for an additional 10 min. Fomite-to-finger transfer trials were conducted to measure concentrations of transferred microorganisms on the fingers after the disinfectant wipe intervention. The mean log10 reduction of the test microorganisms on fomites by the disinfectant wipe treatment varied from 1.9 to 5.0, depending on the microorganism and the fomite. Microbial transfer from disinfectant-wipe-treated fomites was lower (up to <0.1% on average) than from nontreated surfaces (up to 36.3% on average, reported in our previous study) for all types of microorganisms and fomites. This is the first study quantifying microbial transfer from contaminated fomites to fingers after the use of disinfectant wipe intervention. The data generated in the present study can be used in quantitative microbial risk assessment models to predict the effect of disinfectant wipes in reducing microbial exposure. PMID:24610856

  18. Evaluation of a Disinfectant Wipe Intervention on Fomite-to-Finger Microbial Transfer

    PubMed Central

    Lopez, Gerardo U.; Kitajima, Masaaki; Havas, Aaron; Gerba, Charles P.

    2014-01-01

    Inanimate surfaces, or fomites, can serve as routes of transmission of enteric and respiratory pathogens. No previous studies have evaluated the impact of surface disinfection on the level of pathogen transfer from fomites to fingers. Thus, the present study investigated the change in microbial transfer from contaminated fomites to fingers following disinfecting wipe use. Escherichia coli (108 to 109 CFU/ml), Staphylococcus aureus (109 CFU/ml), Bacillus thuringiensis spores (107 to 108 CFU/ml), and poliovirus 1 (108 PFU/ml) were seeded on ceramic tile, laminate, and granite in 10-μl drops and allowed to dry for 30 min at a relative humidity of 15 to 32%. The seeded fomites were treated with a disinfectant wipe and allowed to dry for an additional 10 min. Fomite-to-finger transfer trials were conducted to measure concentrations of transferred microorganisms on the fingers after the disinfectant wipe intervention. The mean log10 reduction of the test microorganisms on fomites by the disinfectant wipe treatment varied from 1.9 to 5.0, depending on the microorganism and the fomite. Microbial transfer from disinfectant-wipe-treated fomites was lower (up to <0.1% on average) than from nontreated surfaces (up to 36.3% on average, reported in our previous study) for all types of microorganisms and fomites. This is the first study quantifying microbial transfer from contaminated fomites to fingers after the use of disinfectant wipe intervention. The data generated in the present study can be used in quantitative microbial risk assessment models to predict the effect of disinfectant wipes in reducing microbial exposure. PMID:24610856

  19. Fluctuations in Saffman-Taylor fingers with quenched disorder

    NASA Astrophysics Data System (ADS)

    Torralba, M.; Ortín, J.; Hernández-Machado, A.; Corvera Poiré, E.

    2006-04-01

    We make an experimental characterization of the effect that static disorder has on the shape of a normal Saffman-Taylor finger. We find that static noise induces a small amplitude and long wavelength instability on the sides of the finger. Fluctuations on the finger sides have a dominant wavelength, indicating that the system acts as a selective amplifier of static noise. The dominant wavelength does not seem to be very sensitive to the intensity of static noise present in the system. On the other hand, at a given flow rate, rms fluctuations of the finger width, decrease with decreasing intensity of static noise. This might explain why the sides of the fingers are flat for typical Saffman-Taylor experiments. Comparison with previous numerical studies of the effect that temporal noise has on the Saffman-Taylor finger, leads to conclude that the effect of temporal noise and static noise are similar. The behavior of fluctuations of the finger width found in our experiments, is qualitatively similar to one recently reported, in the sense that, the magnitude of the width fluctuations decays as a power law of the capillary number, at low flow rates, and increases with capillary number for larger flow rates.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  1. Narrow fingers in the Saffman-Taylor instability

    NASA Astrophysics Data System (ADS)

    Couder, Y.; Gerard, N.; Rabaud, M.

    1986-12-01

    Saffman-Taylor fingers with a relative width much smaller than the classical limit lambda = 0.5 are found when a small isolated bubble is located at their tip. These solutions are members of a family found by Saffman and Taylor (1958) neglecting superficial tension. Recent theories have shown that when capillary forces are taken into account an unphysical cusplike singularity would appear at the tip of all the fingers with lambda less than 0.5. Conversely, here the replacement of the tip by a small bubble makes these solutions possible. At large velocity these fingers show dendritic instability.

  2. Finger rafting: a generic instability of floating elastic sheets.

    PubMed

    Vella, Dominic; Wettlaufer, J S

    2007-02-23

    Colliding ice floes are often observed to form a series of interlocking fingers. We show that this striking phenomenon is not a result of some peculiar property of ice but rather a general and robust mechanical phenomenon reproducible in the laboratory with other floating materials. We determine the theoretical relationship between the width of the resulting fingers and the material's mechanical properties and present experimental results along with field observations to support the theory. The generality of this "finger rafting" suggests that analogous processes may be responsible for creating the large-scale structures observed at the boundaries between Earth's convergent tectonic plates. PMID:17359135

  3. A hierarchical classification method for finger knuckle print recognition

    NASA Astrophysics Data System (ADS)

    Kong, Tao; Yang, Gongping; Yang, Lu

    2014-12-01

    Finger knuckle print has recently been seen as an effective biometric technique. In this paper, we propose a hierarchical classification method for finger knuckle print recognition, which is rooted in traditional score-level fusion methods. In the proposed method, we firstly take Gabor feature as the basic feature for finger knuckle print recognition and then a new decision rule is defined based on the predefined threshold. Finally, the minor feature speeded-up robust feature is conducted for these users, who cannot be recognized by the basic feature. Extensive experiments are performed to evaluate the proposed method, and experimental results show that it can achieve a promising performance.

  4. In vivo correlates of thermoregulatory defense in humans: Temporal course of sub-cortical and cortical responses assessed with fMRI.

    PubMed

    Muzik, Otto; Diwadkar, Vaibhav A

    2016-09-01

    Extensive studies in rodents have established the role of neural pathways that are activated during thermoregulation. However, few studies have been conducted in humans to assess the complex, hierarchically organized thermoregulatory network in the CNS that maintains thermal homeostasis, especially as it pertains to cold exposure. To study the human thermoregulatory network during whole body cold exposure, we have used functional MRI to characterize changes in the BOLD signal within the constituents of the thermoregulatory network in 20 young adult controls during non-noxious cooling and rewarming of the skin by a water-perfused body suit. Our results indicate significant decreases of BOLD signal during innocuous whole body cooling stimuli in the midbrain, the right anterior insula, the right anterior cingulate, and the right inferior parietal lobe. Whereas brain activation in these areas decreased during cold exposure, brain activation increased significantly in the bilateral orbitofrontal cortex during this period. The BOLD signal time series derived from significant activation sites in the orbitofrontal cortex showed opposed phase to those observed in the other brain regions, suggesting complementary processing mechanisms during mild hypothermia. The significance of our findings lies in the recognition that whole body cooling evokes a response in a hierarchically organized thermoregulatory network that distinguishes between cold and warm stimuli. This network seems to generate a highly resolved interoceptive representation of the body's condition that provides input to the orbitofrontal cortex, where higher-order integration takes place and invests internal states with emotional significance that motivate behavior. Hum Brain Mapp 37:3188-3202, 2016. © 2016 Wiley Periodicals, Inc. PMID:27220041

  5. Linear analysis of the heave dynamics of a bag and finger air cushion vehicle skirt

    NASA Astrophysics Data System (ADS)

    Ma, T.; Sullivan, P. A.

    1986-09-01

    A linear analysis of the heave dynamics of an air-cushion vehicle bag and finger skirt is presented. A simplified geometry is considered; this is a two-dimensional section of the skirt without interior compartmentation. The bag is modeled as a membrane having distributed mass and viscoelasticity, and the fingers are modeled as rigid bodies having both mass and moment of inertia. A finite-element technique is used to discretize the equations of motion of the bag, but otherwise standard linear analysis techniques are used to obtain predictions of frequency response and stability characteristics. The stability results confirm the experimental observation that the dominant factor controlling the onset of skirt bounce is the bag-to-cushion pressure ratio.

  6. Hydrophilic Residues Are Crucial for Ribosomal Protein L11 (RPL11) Interaction with Zinc Finger Domain of MDM2 and p53 Protein Activation*

    PubMed Central

    Zhang, Qi; Xiao, Hui; Chai, Sergio C.; Hoang, Quyen Q.; Lu, Hua

    2011-01-01

    Ribosomal protein L11 (RPL11) has been shown to activate p53 by binding to MDM2 and negating its p53 suppression activity in response to ribosomal stress. Although a mutation at Cys-305 within the zinc finger domain of MDM2 has been shown to drastically impair MDM2 interaction with RPL11 and thus escapes the inhibition by this ribosomal protein, it still remains elusive whether RPL11 inactivates MDM2 via direct action on this zinc finger domain and what is the chemical nature of this specific interaction. To define the roles of the MDM2 zinc finger in association with RPL11, we conducted hydrogen-deuterium exchange mass spectrometry, computational modeling, circular dichroism, and mutational analyses of the zinc finger domain of MDM2 and human RPL11. Our study reveals that RPL11 forms a stable complex with MDM2 in vitro through direct contact with its zinc finger. This binding is disrupted by single mutations of non-cysteine amino acids within the zinc finger domain of MDM2. Basic residues in RPL11 are crucial for the stable binding and RPL11 suppression of MDM2 activity toward p53. These results provide the first line of evidence for the specific interaction between RPL11 and the zinc finger of MDM2 via hydrophilic residues as well as a molecular foundation for better understanding RPL11 inhibition of MDM2 function. PMID:21903592

  7. Fingers-of-God effect of infalling satellite galaxies

    NASA Astrophysics Data System (ADS)

    Hikage, Chiaki; Yamamoto, Kazuhiro

    2016-01-01

    Non-linear redshift-space distortion known as the Fingers-of-God (FoG) effect is a major systematic uncertainty in redshift-space distortion studies conducted to test gravity models. The FoG effect has been usually attributed to the random motion of galaxies inside their clusters. When the internal galaxy motion is not well virialized, however, the coherent infalling motion towards the cluster centre generates the FoG effect. Here, we derive an analytical model of the satellite velocity distribution due to the infall motion combined with the random motion. We show that the velocity distribution becomes far from Maxwellian when the infalling motion is dominant. We use simulated subhalo catalogues to find that the contribution of infall motion is important to massive subhaloes and that the velocity distribution has a top-hat like shape as expected from our analytic model. We also study the FoG effect due to infall motion on the redshift-space power spectrum. Using simulated mock samples of luminous red galaxies constructed from haloes and massive subhaloes in N-body simulations, we show that the redshift-space power spectra can differ from expectations when the infall motion is ignored.

  8. Examiner's finger-mounted fetal tissue oximetry

    NASA Astrophysics Data System (ADS)

    Kanayama, Naohiro; Niwayama, Masatsugu

    2014-06-01

    The best way to assess fetal condition is to observe the oxygen status of the fetus (as well as to assess the condition of infants, children, and adults). Previously, several fetal oximeters have been developed; however, no instrument has been utilized in clinical practice because of the low-capturing rate of the fetal oxygen saturation. To overcome the problem, we developed a doctor's finger-mounted fetal tissue oximeter, whose sensor volume is one hundredth of the conventional one. Additionally, we prepared transparent gloves. The calculation algorithm of the hemoglobin concentration was derived from the light propagation analysis based on the transport theory. We measured neonatal and fetal oxygen saturation (StO2) with the new tissue oximeter. Neonatal StO was measured at any position of the head regardless of amount of hair. Neonatal StO was found to be around 77%. Fetal StO was detected in every position of the fetal head during labor regardless of the presence of labor pain. Fetal StO without labor pain was around 70% in the first stage of labor and around 60% in the second stage of labor. We concluded that our new concept of fetal tissue oximetry would be useful for detecting fetal StO in any condition of the fetus.

  9. Finger Length Ratios in Serbian Transsexuals

    PubMed Central

    Vujović, Svetlana; Popović, Srdjan; Mrvošević Marojević, Ljiljana; Ivović, Miomira; Tančić-Gajić, Milina; Stojanović, Miloš; Marina, Ljiljana V.; Barać, Marija; Barać, Branko; Kovačević, Milena; Duišin, Dragana; Barišić, Jasmina; Djordjević, Miroslav L.; Micić, Dragan

    2014-01-01

    Atypical prenatal hormone exposure could be a factor in the development of transsexualism. There is evidence that the 2nd and 4th digit ratio (2D : 4D) associates negatively with prenatal testosterone and positively with estrogens. The aim was to assess the difference in 2D : 4D between female to male transsexuals (FMT) and male to female transsexuals (MFT) and controls. We examined 42 MFT, 38 FMT, and 45 control males and 48 control females. Precise measurements were made by X-rays at the ventral surface of both hands from the basal crease of the digit to the tip using vernier calliper. Control male and female patients had larger 2D : 4D of the right hand when compared to the left hand. Control male's left hand ratio was lower than in control female's left hand. There was no difference in 2D : 4D between MFT and control males. MFT showed similar 2D : 4D of the right hand with control women indicating possible influencing factor in embryogenesis and consequently finger length changes. FMT showed the lowest 2D : 4D of the left hand when compared to the control males and females. Results of our study go in favour of the biological aetiology of transsexualism. PMID:24982993

  10. Ubiquitin interactions of NZF zinc fingers

    PubMed Central

    Alam, Steven L; Sun, Ji; Payne, Marielle; Welch, Brett D; Blake, B Kelly; Davis, Darrell R; Meyer, Hemmo H; Emr, Scott D; Sundquist, Wesley I

    2004-01-01

    Ubiquitin (Ub) functions in many different biological pathways, where it typically interacts with proteins that contain modular Ub recognition domains. One such recognition domain is the Npl4 zinc finger (NZF), a compact zinc-binding module found in many proteins that function in Ub-dependent processes. We now report the solution structure of the NZF domain from Npl4 in complex with Ub. The structure reveals that three key NZF residues (13TF14/M25) surrounding the zinc coordination site bind the hydrophobic ‘Ile44' surface of Ub. Mutations in the 13TF14/M25 motif inhibit Ub binding, and naturally occurring NZF domains that lack the motif do not bind Ub. However, substitution of the 13TF14/M25 motif into the nonbinding NZF domain from RanBP2 creates Ub-binding activity, demonstrating the versatility of the NZF scaffold. Finally, NZF mutations that inhibit Ub binding by the NZF domain of Vps36/ESCRT-II also inhibit sorting of ubiquitylated proteins into the yeast vacuole. Thus, the NZF is a versatile protein recognition domain that is used to bind ubiquitylated proteins during vacuolar protein sorting, and probably many other biological processes. PMID:15029239

  11. From frictional fingers to stick slip bubbles

    NASA Astrophysics Data System (ADS)

    Sandnes, Bjørnar; Jørgen Måløy, Knut; Flekkøy, Eirik; Eriksen, Jon

    2014-05-01

    Gas intrusion into wet porous/deformable/granular media occurs in a wide range of natural and engineered settings. Examples include hydrocarbon recovery, carbon dioxide geo-sequestration, gas venting in sediments and volcanic eruptions. In the case where the intruding gas is able to displace particles and grains, local changes in granular packing fraction govern the evolution of flow paths, resulting in complex pattern formation of the displacement flow. Here we investigate flow patterning as a compressed gas displaces a granular mixture confined in the narrow gap of a Hele-Shaw cell. We find a surprising variety of different pattern formation dynamics, and present a unified phase diagram of the flow morphologies we observe. This talk will focus on one particular transition the system undergoes: from frictional fingers to stick slip bubbles. We show that the frictional fluid flow patterns depend on granular mass loading and system elasticity, analogous to the behaviour of the well-known spring-block sliding friction problem.

  12. Development of Functional Recovery Training Device for Hemiplegic Fingers with Finger-expansion Facilitation Exercise by Stretch Reflex

    NASA Astrophysics Data System (ADS)

    Yu, Yong; Iwashita, Hisashi; Kawahira, Kazumi; Hayashi, Ryota

    This paper develops a functional recovery training device to perform repetition facilitating exercise for hemiplegic finger rehabilitation. On the facilitation exercise, automatic finger expansion can be realized and facilitated by stretch reflex, where a stimulation forces is applied instantaneously on flexion finger for making strech reflex and resistance forces are applied for maintaining the strech reflex. In this paper, novel parallel mechanisms, force sensing system with high sensitivity and resistance accompanying cooperation control method are proposed for sensing, controlling and realizing the stimulation force, resistance forces, strech reflex and repetition facilitating exercise. The effectivities and performances of the device are shown by some experiments.

  13. A three-finger multisensory hand for dexterous space robotic tasks

    NASA Technical Reports Server (NTRS)

    Murase, Yuichi; Komada, Satoru; Uchiyama, Takashi; Machida, Kazuo; Akita, Kenzo

    1994-01-01

    The National Space Development Agency of Japan will launch ETS-7 in 1997, as a test bed for next generation space technology of RV&D and space robot. MITI has been developing a three-finger multisensory hand for complex space robotic tasks. The hand can be operated under remote control or autonomously. This paper describes the design and development of the hand and the performance of a breadboard model.

  14. The generation of zinc finger proteins by modular assembly

    PubMed Central

    Bhakta, Mital; Segal, David J.

    2015-01-01

    The modular assembly (MA) method of generating engineered zinc finger proteins (ZFPs) was the first practical method for creating custom DNA-binding proteins. As such, MA has enabled a vast exploration of sequence-specific methods and reagents, ushering in the modern era of zinc finger-based applications that are described in this volume. The first zinc finger nuclease to cleave an endogenous site was created using MA, as was the first artificial transcription factor to enter phase II clinical trials. In recent years, other excellent methods have been developed that improved the affinity and specificity of the engineered ZFPs. However, MA is still used widely for many applications. This chapter will describe methods and give guidance for the creation of ZFPs using MA. Such ZFPs might be useful as starting materials to perform other methods described in this volume. Here, we also describe a single-strand annealing recombination assay for the initial testing of zinc finger nucleases. PMID:20680825

  15. L'index significant (The Pointed Index Finger).

    ERIC Educational Resources Information Center

    Calbris, G.

    1979-01-01

    In the framework of a study of nonverbal communication, the various meanings attached to the pointed index finger are analyzed. The question is raised as to what extent the findings hold for cultures other than French. (AMH)

  16. Seal finger: A case report and review of the literature

    PubMed Central

    White, Colin P; Jewer, David D

    2009-01-01

    A recent case of seal finger which was misdiagnosed and hence mistreated at the patient’s first presentation is described. The patient was eventually referred to a hand specialist and after the correct treatment with tetracycline, responded well without any long-term sequelae. Seal finger is an occupational injury that occurs to those who work directly or indirectly with seals. The disease entity has been described in both Scandinavian and Canadian literature. The causative microorganism was unknown until 1991, when Mycoplasma phocacerebrale was isolated from both the finger of a patient with seal finger and from the mouth of a seal that bit the patient. Although rare, the disease is not uncommon in marine workers, biologists and veterinarians. Prompt identification based on patient history and treatment with oral tetracycline is pendant to a favourable patient outcome. PMID:21119845

  17. Finger vein recognition based on local directional code.

    PubMed

    Meng, Xianjing; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2012-01-01

    Finger vein patterns are considered as one of the most promising biometric authentication methods for its security and convenience. Most of the current available finger vein recognition methods utilize features from a segmented blood vessel network. As an improperly segmented network may degrade the recognition accuracy, binary pattern based methods are proposed, such as Local Binary Pattern (LBP), Local Derivative Pattern (LDP) and Local Line Binary Pattern (LLBP). However, the rich directional information hidden in the finger vein pattern has not been fully exploited by the existing local patterns. Inspired by the Webber Local Descriptor (WLD), this paper represents a new direction based local descriptor called Local Directional Code (LDC) and applies it to finger vein recognition. In LDC, the local gradient orientation information is coded as an octonary decimal number. Experimental results show that the proposed method using LDC achieves better performance than methods using LLBP. PMID:23202194

  18. Finger Vein Recognition Based on Local Directional Code

    PubMed Central

    Meng, Xianjing; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2012-01-01

    Finger vein patterns are considered as one of the most promising biometric authentication methods for its security and convenience. Most of the current available finger vein recognition methods utilize features from a segmented blood vessel network. As an improperly segmented network may degrade the recognition accuracy, binary pattern based methods are proposed, such as Local Binary Pattern (LBP), Local Derivative Pattern (LDP) and Local Line Binary Pattern (LLBP). However, the rich directional information hidden in the finger vein pattern has not been fully exploited by the existing local patterns. Inspired by the Webber Local Descriptor (WLD), this paper represents a new direction based local descriptor called Local Directional Code (LDC) and applies it to finger vein recognition. In LDC, the local gradient orientation information is coded as an octonary decimal number. Experimental results show that the proposed method using LDC achieves better performance than methods using LLBP. PMID:23202194

  19. Finger Growth in Surfactant Solution in Hele-Shaw Cells

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takehiro; Yamashita, Atsushi; Nakamura, Yousuke; Hashimoto, Takamasa; Mori, Noriyasu

    2006-05-01

    Viscous fingering in surfactant solutions was experimentally studied. Aqueous solutions of cetyltrimethylammonium bromide (CTAB) with sodium salicylate (NaSal) as a counter ion were used as test fluids. Excess of counter ion was added into a surfactant solution of CTAB to configure network structures of wormlike micelles. The experiments were mainly carried out using a square Hele-Shaw cell. The structure of fingering pattern was dimensionally analyzed to classify the patterns into three types. In addition, growth phenomena distinguishing for the viscous finger in the CTAB/NaSal solutions were observed: surface instabilities with dendrites, and a sudden protrusion from a cuspidate shaped finger tip. The dependence of the sudden protrusion on the shear rate was confirmed by the experiment using a rectangular cell.

  20. Tension Distribution in a Tendon-Driven Robotic Finger

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  1. Suppression of viscous fingering in nonflat Hele-Shaw cells.

    PubMed

    Brandão, Rodolfo; Fontana, João V; Miranda, José A

    2014-11-01

    Viscous fingering formation in flat Hele-Shaw cells is a classical and widely studied fluid mechanical problem. Recently, instead of focusing on the development of the fingering instability, researchers have devised different strategies aiming to suppress its appearance. In this work, we study a protocol that intends to inhibit the occurrence of fingering instabilities in nonflat (spherical and conical) Hele-Shaw cell geometries. By using a mode-coupling theory to describe interfacial evolution, plus a variational controlling technique, we show that viscous fingering phenomena can be minimized in such a confined, curved environment by properly manipulating a time-dependent injection flow rate Q(t). Explicit expressions for Q(t) are derived for the specific cases of spherical and conical cells. The suitability of the controlling method is verified for linear and weakly nonlinear stages of the flow. PMID:25493877

  2. The putative zinc finger of a caulimovirus is essential for infectivity but does not influence gene expression.

    PubMed

    Scholthof, H B; Wu, F C; Kiernan, J M; Shepherd, R J

    1993-04-01

    Plant pararetroviruses, such as caulimoviruses, and animal retroviruses have in common the presence of a highly conserved arrangement of cysteines and a histidine in the precursor of the capsid protein. The composition of these amino acids resembles a zinc finger element, a structure that is common to a class of eukaryotic proteins that regulate gene expression. The role of the putative zinc finger in the life-cycle of caulimoviruses was investigated by introducing specific mutations in the coat protein coding region of a cloned and infectious form of figwort mosaic virus, a caulimovirus. This mutated viral genome, which no longer encoded the conserved cysteine and histidine residues, was not infectious in plants. Transient expression assays in protoplasts showed that expression of a reporter gene inserted at different places in the genome was not detectably influenced by the coat protein or its putative zinc finger. It appears that the zinc finger-like element of caulimoviruses is not involved in the regulation of gene expression. These observations support a model which predicts a function of the zinc finger in specific recognition and packaging of viral RNA into virions prior to reverse transcription. PMID:8468560

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

    PubMed

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

    1993-01-01

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

  4. The effects of vibration-reducing gloves on finger vibration

    PubMed Central

    Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

    2015-01-01

    Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration can cause hand-arm vibration syndrome. Vibration-reducing gloves have been used as an alternative approach to reduce the vibration exposure. However, their effectiveness for reducing finger-transmitted vibrations remains unclear. This study enhanced the understanding of the glove effects on finger vibration and provided useful information on the effectiveness of typical VR gloves at reducing the vibration transmitted to the fingers. The new

  5. Fingered bola body, bola with same, and methods of use

    NASA Technical Reports Server (NTRS)

    Dzenitis, John M. (Inventor); Billica, Linda W. (Inventor)

    1994-01-01

    The present invention discloses bola bodies, bolas, and a snaring method which makes use such devices. A bola body, according to the present invention, is nonspherical or irregular in shape rather than a smooth sphere or ovoid body. One or more fingers extends from the bola body. These fingers may be relatively straight or they may have crooked or bent portions to enhance entanglement with a bola line or lines or with each other. Two or more of such fingers may be used and may be regularly or irregularly spaced apart on a bola body. A bola with such bodies includes lines which are connected to the other bodies. In one particular embodiment of a bola body, according to the present invention, the body has an irregular shape with a bottom rectangular portion and a top pyramid portion forming a nose. A plurality of fingers is extended from the pyramidal top portion with one finger extended up and away from each of four corners of the top portion. Such a bola body tends to be initially oriented with its nose and fingers against an object being snared since the body is pulled nose first when a bola line is secured at the tip of the pyramidal portion of the bola body. With such a bola, an unwrapping bola body can slip around a target member so that two of the rod-shaped fingers catch a bola line and guide it into an area or crook between the fingers and a side of the top pyramidal portion of the bola body. Tension on the bola line maintains the line in the crook and tends to press the fingers against the unwrapped target member to stabilize the wrapping of the line about the target member. With such a bola, it is difficult for two or more lines unwrapping in different directions to move past one another without being forced together by line tension. Also, the fingers of such bola bodies may hook and hold each other. The fingers may also hook or entangle some object on or portion of the target member. A probable known target member has known dimensions and shapes so that

  6. Impact of protein and carbohydrate supplementation on plasma volume expansion and thermoregulatory adaptation by aerobic training in older men.

    PubMed

    Okazaki, Kazunobu; Ichinose, Takashi; Mitono, Hiroyuki; Chen, Mian; Masuki, Shizue; Endoh, Hiroshi; Hayase, Hideki; Doi, Tatsuya; Nose, Hiroshi

    2009-09-01

    We examined whether protein-carbohydrate (CHO) supplementation immediately after exercise each day during aerobic training facilitated plasma volume (PV) expansion and thermoregulatory and cardiovascular adaptations in older men. Fourteen moderately active older men [68 +/- 5 (SD) yr] were divided into two groups so as to have no significant differences in anthropometric measures, PV, and peak oxygen consumption rate (Vo(2peak)). Each group was provided with a mixture of protein and CHO (3.2 kcal, 0.18 g protein/kg body wt, Pro-CHO, n = 7) or a non-protein and low-calorie placebo (0.5 kcal, 0 g protein/kg body wt, CNT, n = 7) immediately after cycling exercise (60-75% Vo(2peak), 60 min/day, 3 days/wk) each day for 8 wk at approximately 19 degrees C ambient temperature (T(a)) and approximately 43% relative humidity (RH). Before and after training, we measured PV, cardiac stroke volume (SV), and esophageal temperature (T(es)) during 20-min exercise at 60% of pretraining Vo(2peak) at 30 degrees C T(a) and 50% RH. Moreover, we determined the sensitivity of the chest sweat rate (DeltaSR/DeltaT(es)) and forearm vascular conductance (DeltaFVC/DeltaT(es)) in response to increased T(es) during exercise. After training, PV increased by approximately 6% in Pro-CHO (P < 0.001), with an approximately 10% increase in SV during exercise (P < 0.001), but not in CNT (P > 0.07). DeltaFVC/DeltaT(es) increased by 80% and DeltaSR/DeltaT(es) by 18% in Pro-CHO (both P < 0.01) but not in CNT (P > 0.07). Moreover, we found a significant interactive effect of group x training on PV, SV, and DeltaFVC/DeltaT(es) (all P < 0.02) but with no significant effect of group (P > 0.4), suggesting that the supplement enhanced these responses to aerobic training. Thus postexercise protein-CHO supplementation during training caused PV expansion and facilitated thermoregulatory and cardiovascular adaptations, possibly providing a new training regimen for older men. PMID:19608927

  7. Finger blood content, light transmission, and pulse oximetry errors.

    PubMed

    Craft, T M; Lawson, R A; Young, J D

    1992-01-01

    The changes in light emitting diode current necessary to maintain a constant level of light incident upon a photodetector were measured in 20 volunteers at the two wavelengths employed by pulse oximeters. Three states of finger blood content were assessed; exsanguinated, hyperaemic, and normal. The changes in light emitting diode current with changes in finger blood content were small and are not thought to represent a significant source of error in saturation as measured by pulse oximetry. PMID:1536406

  8. Detecting overblown flute fingerings from the residual noise spectrum.

    PubMed

    Verfaille, Vincent; Depalle, Philippe; Wanderley, Marcelo M

    2010-01-01

    Producing a tone by increasing the blowing pressure to excite a higher frequency impedance minimum, or overblowing, is widely used in standard flute technique. In this paper, the effect of overblowing a fingering is explored with spectral analysis, and a fingering detector is designed based on acoustical knowledge and pattern classification techniques. The detector performs signal analysis of the strong broadband signal, that is, spectrally shaped by the pipe impedance, and measures the spectral energy during the attack around multiples of the fundamental frequency sub-multiples over the first octave and a half. It is trained and evaluated on sounds recorded with four expert performers. They played six series of tones from overblown and regular fingerings, with frequencies that are octave- and non-octave-related to the playing frequency. The best of the four proposed sound descriptors allows for a detection error below 1.3% for notes with two and three fingerings (C(5), D(5), C(6), and Cmusical sharp(6)) and below 14% for four (E(6)) or five fingerings (G(6)). The error is shown to dramatically increase when two fingerings' impedance become too similar (E(6) and A(4) and G(6) and C(5)). PMID:20058998

  9. Fluidic Channels Produced by Electro Hydrodynamic Viscous Fingering

    NASA Astrophysics Data System (ADS)

    Behler, Kristopher; Wetzel, Eric

    2010-03-01

    Viscous fingering is a term describing fingerlike extensions of liquid from a column of low viscosity liquid that has been injected into a more viscous liquid. The modification of viscous fingering, known as electro hydrodynamic viscous fingering (EHVF), utilizes large electrical potentials of 10-60 kV. The fingers see a reduction in size and increase in branching behavior due to the potential applied to the system. The resulting finely structured patterns are analogous to biological systems such as blood vessels and the lymphatic system. In this study silicone oils and water were studied in thin channel Hele-Shaw cells. The interfacial tension was optimized by altering the surfactant concentration in the silicone oils. EHVF of liquid filled packed beds consisting of beads and silicone oils showed retardation of the relaxation of the fingers after the voltage was turned off. Decreased relaxation provides a means to solidify patterns into a curable material, such as polydimethylsiloxane (PDMS). After the water is evacuated from the fingers, the cured materials then possess hollow channels that can be refilled and emptied, thus creating an artificial circulatory system.

  10. Integrating optical finger motion tracking with surface touch events.

    PubMed

    MacRitchie, Jennifer; McPherson, Andrew P

    2015-01-01

    This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction. PMID:26082732

  11. Integrating optical finger motion tracking with surface touch events

    PubMed Central

    MacRitchie, Jennifer; McPherson, Andrew P.

    2015-01-01

    This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction. PMID:26082732

  12. Viscous Fingering Induced Flow Instability in Multidimensional Liquid Chromatography

    SciTech Connect

    Mayfield, Kirsty; Shalliker, R. Andrew; Catchpoole, Heather J.; Sweeney, Alan P.; Wong, Victor; Guiochon, Georges A

    2005-07-01

    Viscous fingering is a flow instability phenomenon that results in the destabilisation of the interface between two fluids of differing viscosities. The destabilised interface results in a complex mixing of the two fluids in a pattern that resembles fingers. The conditions that enhance this type of flow instability can be found in coupled chromatographic separation systems, even when the solvents used in each of the separation stages have seemingly similar chemical and physical properties (other than viscosity). For example, the viscosities of acetonitrile and methanol are sufficiently different that instability at the interface between these two solvents can be established and viscous fingering results. In coupled chromatographic systems, the volume of solvent transported from one separation dimension to the second often exceeds the injection volume by two or more orders of magnitude. As a consequence, viscous fingering may occur, when otherwise following the injection of normal analytical size injection plugs viscous fingering would not occur. The findings in this study illustrate the onset of viscous fingering in emulated coupled chromatographic systems and show the importance of correct solvent selection for optimum separation performance.

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

    PubMed

    Çulha, Utku; Iida, Fumiya

    2016-04-01

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

  14. Multiple states of finger propagation in partially occluded tubes

    NASA Astrophysics Data System (ADS)

    Hazel, A. L.; Pailha, M.; Cox, S. J.; Juel, A.

    2013-06-01

    Recent experiments by Pailha et al. [Phys. Fluids 24, 021702 (2012), 10.1063/1.3682772] uncovered a rich array of propagation modes when air displaces oil from axially uniform tubes that have local variations in flow resistance within their cross-sections. The behaviour is particularly surprising because only a single, symmetric mode has been observed in tubes of regular cross-section, e.g., circular, elliptical, rectangular, and polygonal. In this paper, we present experimental results describing a new mode, an asymmetric localised air finger, that persists in the limit of zero propagation speed. We show that the experimental observations are consistent with a model based on capillary static calculations within the tube's cross-section, and the observed bistability is a consequence of the existence of multiple solutions to the Young-Laplace equations. The model also provides an upper bound for the previously reported symmetry-breaking bifurcation [A. de Lózar, A. Heap, F. Box, A. L. Hazel, and A. Juel, Phys. Fluids 21, 101702 (2009), 10.1063/1.3247879].

  15. Generalization through similarity: motif discourse in the discovery and elaboration of zinc finger proteins

    PubMed Central

    Condit, Celeste Michelle; Railsback, L Bruce

    2007-01-01

    Background Biological organisms and their components are better conceived within categories based on similarity rather than on identity. Biologists routinely operate with similarity-based concepts such as "model organism" and "motif." There has been little exploration of the characteristics of the similarity-based categories that exist in biology. This study uses the case of the discovery and classification of zinc finger proteins to explore how biological categories based in similarity are represented. Results The existence of a category of "zinc finger proteins" was based in 1) a lumpy gradient of similarity, 2) a link between function and structure, 3) establishment of a range of appearance across systems and organisms, and 4) an evolutionary locus as a historically based common-ground. Conclusion More systematic application of the idea of similarity-based categorization might eliminate the assumption that biological characteristics can only contribute to narrow categorization of humans. It also raises possibilities for refining data-driven exploration efforts. PMID:17915020

  16. Motion representation of the long fingers: a proposal for the definitions of new anatomical frames.

    PubMed

    Coupier, Jérôme; Moiseev, Fédor; Feipel, Véronique; Rooze, Marcel; Van Sint Jan, Serge

    2014-04-11

    Despite the availability of the International Society of Biomechanics (ISB) recommendations for the orientation of anatomical frames, no consensus exists about motion representations related to finger kinematics. This paper proposes novel anatomical frames for motion representation of the phalangeal segments of the long fingers. A three-dimensional model of a human forefinger was acquired from a non-pathological fresh-frozen hand. Medical imaging was used to collect phalangeal discrete positions. Data processing was performed using a customized software interface ("lhpFusionBox") to create a specimen-specific model and to reconstruct the discrete motion path. Five examiners virtually palpated two sets of landmarks. These markers were then used to build anatomical frames following two methods: a reference method following ISB recommendations and a newly-developed method based on the mean helical axis (HA). Motion representations were obtained and compared between examiners. Virtual palpation precision was around 1mm, which is comparable to results from the literature. The comparison of the two methods showed that the helical axis method seemed more reproducible between examiners especially for secondary, or accessory, motions. Computed Root Mean Square distances comparing methods showed that the ISB method displayed a variability 10 times higher than the HA method. The HA method seems to be suitable for finger motion representation using discrete positions from medical imaging. Further investigations are required before being able to use the methodology with continuous tracking of markers set on the subject's hand. PMID:24612716

  17. Effect of incorporation of thermo-regulatory genes into exotic layers on egg production and quality under tropical environment.

    PubMed

    Hagan, Julius K; Adomako, Kwaku; Olympio, Simon Oscar

    2014-01-01

    A breed development strategy aimed at making exotic layers (Lohmann Brown) more productive under tropical environment using thermo-regulatory genes is underway at Akate Farms in Kumasi, Ghana. The present experiment was carried out to find out the effect of the genes on egg production in hot and humid environments. Three genetic groups comprising naked-neck, frizzle and their normally feathered sibs were obtained after successive generations of crossing between naked-neck and frizzle cocks and Lohmann brown hens. A total of 270 18-week-old pullets, 90 each of the 3 groups, were selected randomly and assigned to a completely randomized design experiment with 3 replicates, with 30 birds in each replicate group and kept up to a period of 72 weeks. The birds were kept in a partitioned open-sided deep-litter house constructed with sandcrete blocks with 30 pullets in each compartment. They were fed ad libitum with layer diets containing 18 % crude protein and 2,800 kcal ME/kg. Results obtained showed that the crossbred naked-neck and frizzle phenotypes produced eggs at a significantly (P < 0.05) higher rates than their normally feathered sibs and also out-performed their normally feathered sibs in other egg production parameters measured, even though they all segregated from similar parents. This is an indication of the favourable effect of the genes on egg production under hot and humid environments. PMID:23955013

  18. The effect of thermal quality on the thermoregulatory behavior of the bearded dragon Pogona vitticeps: influences of methodological assessment.

    PubMed

    Cadena, Viviana; Tattersall, Glenn J

    2009-01-01

    Metabolic functions are generally optimized within a narrow range of body temperatures (T(b)'s), conferring thermoregulation great importance to the survival and fitness of an animal. In lizards, T(b) regulation is mainly behavioral, and the metabolic costs associated with behavioral thermoregulation are primarily locomotory. In reptiles, however, it has been proposed that they thermoregulate less precisely when the associated costs, metabolic or otherwise, are high. Such a strategy enhances fitness by allowing lizards to be more flexible to changing environmental conditions while maximizing the benefits of maintaining a high T(b) and minimizing energy expenditure. We evaluated the behavioral thermoregulation of inland bearded dragons Pogona vitticeps under various thermal quality conditions requiring different locomotory investment for thermoregulation. The selected ambient temperature and preferred T(b) ranges increased at lower environmental thermal qualities, indicating a decrease in thermoregulatory precision in environments where the costs associated with thermoregulation were high. The level of thermoregulation was also affected, exhibiting a decrease in preferred T(b) of approximately 2 degrees C at the lowest-thermal-quality treatment. These data provide important implications for the procedural assessment of preferred T(b) and a better understanding of thermal set points in reptiles in general. Our results emphasize that the precise maintenance and assessment of preferred T(b) is contingent on the quality of the environment, laboratory or natural, that the animal inhabits. PMID:19323642

  19. Thermoregulatory responses during exercise and a hot water immersion and the affective responses to peripheral thermal stimuli

    NASA Astrophysics Data System (ADS)

    Fujishima, K.

    1986-03-01

    Tympanic (Tty), mean skin (¯Tsk) and mean body (¯Tb) temperatures and heart rate (HR) increased more in low Vo2 max group (LG) than in high Vo2 max group (HG) during exercise. The regression coefficient of body temperatures (Tty and ¯Tb) on HR and the increased rate of heat storage were larger in LG than in HG during exercise. The local sweat rate (per min/cm2) during a hot water bath exhibited a considerable large quantity in comparison with the amount during exercise. Internal and skin temperatures during a hot water bath increased more immediately than those during exercise. The levels of comfort sensation during the preovulatory phase in women and pre-exercise period in men were higher at 40‡C than at 20‡C as peripheral thermal stimulus. The levels during the postovulatory and post-exercise phases in the same subjects were higher with the cool stimuli than with the warm stimuli. Above results suggest that thermoregulatory responses during submaximal exercise are different according to physical fitness and that these responses are different from those during hot water immersion. In addition, these suggest that the scores of thermal sensation with warm and cool stimuli are different during the pre- and post-ovulatory phases and the pre- and post-exercise periods.

  20. The Use of an MEG/fMRI-Compatible Finger Motion Sensor in Detecting Different Finger Actions

    PubMed Central

    Yong, Xinyi; Li, Yasong; Menon, Carlo

    2016-01-01

    This paper explores the use of a novel device in detecting different finger actions among healthy individuals and individuals with stroke. The device is magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) compatible. It was prototyped to have four air-filled chambers that are made of silicone elastomer, which contains low magnetizing materials. When an individual compresses the device with his/her fingers, each chamber experiences a change in pressure, which is detected by a pressure sensor. In a previous recent work, our device was shown to be MEG/fMRI compatible. In this study, our research effort focuses on using the device to detect different finger actions (e.g., grasping and pinching) in non-shielded rooms. This is achieved by applying a support vector machine to the sensor data collected from the device when participants are resting and executing the different finger actions. The total number of possible finger actions that can be executed using the device is 31. The healthy participants could perform all the 31 different finger actions and the average classification accuracy achieved is 95.53 ± 2.63%. The stroke participants could perform all the 31 different finger actions with their healthy hand and the average classification accuracy achieved is 83.13 ± 6.69%. Unfortunately, the functions of their affected hands are compromised due to stroke. Thus, the number of finger actions they could perform ranges from 2 to 24, depending on the level of impairments. The average classification accuracy for the affected hand is 83.99 ± 16.38%. The ability to identify different finger actions using the device can provide a mean to researchers to label the data automatically in MEG/fMRI studies. In addition, the sensor data acquired from the device provide sensorimotor-­related information, such as speed and force, when the device is compressed. Thus, brain activations can be correlated with this information during different

  1. Zinc Finger Structures in the Human Immunodeficiency Virus Type 1 Nucleocapsid Protein Facilitate Efficient Minus- and Plus-Strand Transfer

    PubMed Central

    Guo, Jianhui; Wu, Tiyun; Anderson, Jada; Kane, Bradley F.; Johnson, Donald G.; Gorelick, Robert J.; Henderson, Louis E.; Levin, Judith G.

    2000-01-01

    The nucleocapsid protein (NC) of human immunodeficiency virus type 1 (HIV-1) has two zinc fingers, each containing the invariant metal ion binding residues CCHC. Recent reports indicate that mutations in the CCHC motifs are deleterious for reverse transcription in vivo. To identify reverse transcriptase (RT) reactions affected by such changes, we have probed zinc finger functions in NC-dependent RT-catalyzed HIV-1 minus- and plus-strand transfer model systems. Our approach was to examine the activities of wild-type NC and a mutant in which all six cysteine residues were replaced by serine (SSHS NC); this mutation severely disrupts zinc coordination. We find that the zinc fingers contribute to the role of NC in complete tRNA primer removal from minus-strand DNA during plus-strand transfer. Annealing of the primer binding site sequences in plus-strand strong-stop DNA [(+) SSDNA] to its complement in minus-strand acceptor DNA is not dependent on NC zinc fingers. In contrast, the rate of annealing of the complementary R regions in (−) SSDNA and 3′ viral RNA during minus-strand transfer is approximately eightfold lower when SSHS NC is used in place of wild-type NC. Moreover, unlike wild-type NC, SSHS NC has only a small stimulatory effect on minus-strand transfer and is essentially unable to block TAR-induced self-priming from (−) SSDNA. Our results strongly suggest that NC zinc finger structures are needed to unfold highly structured RNA and DNA strand transfer intermediates. Thus, it appears that in these cases, zinc finger interactions are important components of NC nucleic acid chaperone activity. PMID:10982342

  2. Extrinsic Finger and Thumb Muscles Command a Virtual Hand to Allow Individual Finger and Grasp Control

    PubMed Central

    Hargrove, Levi J.; Weir, Richard F. ff.; Kuiken, Todd A.

    2015-01-01

    Fine-wire intramuscular electrodes were used to obtain EMG signals from six extrinsic hand muscles associated with the thumb, index, and middle fingers. Subjects’ EMG activity was used to control a virtual three-DOF hand as they conformed the hand to a sequence of hand postures testing two controllers: direct EMG control and pattern recognition control. Subjects tested two conditions using each controller: starting the hand from a pre-defined neutral posture before each new posture and starting the hand from the previous posture in the sequence. Subjects demonstrated their ability to simultaneously, yet individually, move all three DOFs during the direct EMG control trials, however results showed subjects did not often utilize this feature. Performance metrics such as failure rate and completion time showed no significant difference between the two controllers. PMID:25099395

  3. Magic Ring: A Finger-Worn Device for Multiple Appliances Control Using Static Finger Gestures

    PubMed Central

    Jing, Lei; Zhou, Yinghui; Cheng, Zixue; Huang, Tongjun

    2012-01-01

    An ultimate goal for Ubiquitous Computing is to enable people to interact with the surrounding electrical devices using their habitual body gestures as they communicate with each other. The feasibility of such an idea is demonstrated through a wearable gestural device named Magic Ring (MR), which is an original compact wireless sensing mote in a ring shape that can recognize various finger gestures. A scenario of wireless multiple appliances control is selected as a case study to evaluate the usability of such a gestural interface. Experiments comparing the MR and a Remote Controller (RC) were performed to evaluate the usability. From the results, only with 10 minutes practice, the proposed paradigm of gestural-based control can achieve a performance of completing about six tasks per minute, which is in the same level of the RC-based method. PMID:22778612

  4. A study of white finger in the gas industry.

    PubMed Central

    Walker, D D; Jones, B; Ogston, S; Tasker, E G; Robinson, A J

    1985-01-01

    Men engaged in breaking or reinstating road surfaces are exposed to vibration from mechanical tools. In view of the lack of epidemiological information on vibration white finger in such a population, a survey was carried out to identify the prevalence of symptoms of white finger in a sample of men using these tools in the gas industry and to compare the prevalence with that found in a control group not occupationally exposed to vibration. Altogether 905 men (97%) in the gas industry and 552 men (92%) in the control group were interviewed, using a questionnaire from which the presence or absence of white finger symptoms from all causes was noted. The prevalence of white finger was 9.6% in the group exposed to vibration at work compared with 9.5% in the control group. The prevalence in the former group when adjusted for age differences between the survey and control populations was 12.2%, but this difference did not reach statistical significance. In case the approach of comparing prevalences of white finger from all causes might have obscured any contributory effect of vibration, the prevalence of white finger was examined in relation to the number of years vibrating tools had been used, this being the only measure of exposure to vibration available. No direct association was found between the prevalence of symptoms and number of years vibrating tools had been used. In view of this and the absence of a significant excess of white finger symptoms in the group using vibratory tools, the authors conclude that vibration white finger is not a special problem in the gas industry. Nevertheless, experimental tests carried out on the different types of roadbreakers used in the industry and on different road surfaces indicate that the vibration levels exceed the standards advocated in the draft international standard DIS 5349 (1979) at the lower end of the frequency spectrum. That no particular problem has been found may be due to the relatively short exposures to vibration

  5. A structural approach reveals how neighbouring C2H2 zinc fingers influence DNA binding specificity

    PubMed Central

    Garton, Michael; Najafabadi, Hamed S.; Schmitges, Frank W.; Radovani, Ernest; Hughes, Timothy R.; Kim, Philip M.

    2015-01-01

    Development of an accurate protein–DNA recognition code that can predict DNA specificity from protein sequence is a central problem in biology. C2H2 zinc fingers constitute by far the largest family of DNA binding domains and their binding specificity has been studied intensively. However, despite decades of research, accurate prediction of DNA specificity remains elusive. A major obstacle is thought to be the inability of current methods to account for the influence of neighbouring domains. Here we show that this problem can be addressed using a structural approach: we build structural models for all C2H2-ZF–DNA complexes with known binding motifs and find six distinct binding modes. Each mode changes the orientation of specificity residues with respect to the DNA, thereby modulating base preference. Most importantly, the structural analysis shows that residues at the domain interface strongly and predictably influence the binding mode, and hence specificity. Accounting for predicted binding mode significantly improves prediction accuracy of predicted motifs. This new insight into the fundamental behaviour of C2H2-ZFs has implications for both improving the prediction of natural zinc finger-binding sites, and for prioritizing further experiments to complete the code. It also provides a new design feature for zinc finger engineering. PMID:26384429

  6. On Frictional Forces between the Finger and a Textured Surface during Active Touch.

    PubMed

    Janko, Marco; Primerano, Richard; Visell, Yon

    2016-01-01

    We investigated forces felt by a bare finger in sliding contact with a textured surface, and how they depend on properties of the surface and contact interaction. Prior research has shed light on haptic texture perception. Nevertheless, how texture-produced forces depend on the properties of a touched object or the way that it is touched is less clear. To address this, we designed an apparatus to accurately measure contact forces between a sliding finger and a textured surface. We fabricated textured surfaces, and measured spatial variations in forces produced as subjects explored the surfaces with a bare finger. We analyzed variations in these force signals, and their dependence on object geometry and contact parameters. We observed a number of phenomena, including transient stick-slip behavior, nonlinearities, phase variations, and large force fluctuations, in the form of aperiodic signal components that proved difficult to model for fine surfaces. Moreover, metrics such as total harmonic distortion and normalized variance decreased as the spatial scale of the stimuli increased. The results of this study suggest that surface geometry and contact parameters are insufficient to account for force production during such interactions. Moreover, the results shed light on perceptual challenges solved by the haptic system during active touch sensing of surface texture. PMID:26685262

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

    PubMed

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

    2015-06-01

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

  8. Parkinsonism reduces coordination of fingers, wrist, and arm in fine motor control.

    PubMed

    Teulings, H L; Contreras-Vidal, J L; Stelmach, G E; Adler, C H

    1997-07-01

    This experiment investigates movement coordination in Parkinson's disease (PD) subjects. Seventeen PD patients and 12 elderly control subjects performed several handwriting-like tasks on a digitizing writing tablet resting on top of a table in front of the subject. The writing patterns, in increasing order of coordination complexity, were repetitive back-and-forth movements in various orientations, circles and loops in clockwise and counterclockwise directions, and a complex writing pattern. The patterns were analyzed in terms of jerk normalized for duration and size per stroke. In the PD subjects, back-and-forth strokes, involving coordination of fingers and wrist, showed larger normalized jerk than strokes performed using either the wrist or the fingers alone. In the PD patients, wrist flexion (plus radial deviation) showed greater normalized jerk in comparison to wrist extension (plus ulnar deviation). The elderly control subjects showed no such effects as a function of coordination complexity. For both PD and elderly control subjects, looping patterns consisting of circles with a left-to-right forearm movement, did not show a systematic increase of normalized jerk. The same handwriting patterns were then simulated using a biologically inspired neural network model of the basal ganglia thalamocortical relations for a control and a mild PD subject. The network simulation was consistent with the observed experimental results, providing additional support that a reduced capability to coordinate wrist and finger movements may be caused by suboptimal functioning of the basal ganglia in PD. The results suggest that in PD patients fine motor control problems may be caused by a reduced capability to coordinate the fingers and wrist and by reduced control of wrist flexion. PMID:9225749

  9. Exploration of the Zinc Finger Motif in Controlling Activity of Matrix Metalloproteinases

    PubMed Central

    2015-01-01

    Discovering ways to control the activity of matrix metalloproteinases (MMPs), zinc-dependent enzymes capable of degrading extracellular matrix proteins, is an important field of cancer research. We report here a novel strategy for assembling MMP inhibitors on the basis of oligopeptide ligands by exploring the pattern known as the zinc finger motif. Advanced molecular modeling tools were used to characterize the structural binding motifs of experimentally tested MMP inhibitors, as well as those of newly proposed peptidomimetics, in their zinc-containing active sites. The results of simulations based on the quantum mechanics/molecular mechanics (QM/MM) approach and Car–Parrinello molecular dynamics with QM/MM potentials demonstrate that, upon binding of Regasepin1, a known MMP-9 inhibitor, the Zn2+(His3) structural element is rearranged to the Zn2+(Cys2His2) zinc finger motif, in which two Cys residues are borrowed from the ligand. Following consideration of the crystal structure of MMP-2 with its inhibitor, the oligopeptide APP-IP, we proposed a new peptidomimetic with two replacements in the substrate, Tyr3Cys and Asp6Cys. Simulations show that this peptide variant blocks an enzyme active site by the Zn2+(Cys2His2) zinc finger construct. Similarly, a natural substrate of MMP-2, Ace-Gln-Gly ∼ Ile-Ala-Gly-Nme, can be converted to an inhibiting compound by two replacements, Ile by Cys and Gly by the d isomer of Cys, favoring formation of the zinc finger motif. PMID:25375834

  10. Excitation of Gravity Waves by Fingering Convection, and the Formation of Compositional Staircases in Stellar Interiors

    NASA Astrophysics Data System (ADS)

    Garaud, P.; Medrano, M.; Brown, J. M.; Mankovich, C.; Moore, K.

    2015-07-01

    Fingering convection (or thermohaline convection) is a weak yet important kind of mixing that occurs in stably stratified stellar radiation zones in the presence of an inverse mean molecular weight gradient. Brown et al. recently proposed a new model for mixing by fingering convection, which contains no free parameter and was found to fit the results of direct numerical simulations in almost all cases. Notably, however, they found that mixing was substantially enhanced above their predicted values in the few cases where large-scale gravity waves, followed by thermo-compositional layering, grew spontaneously from the fingering convection. This effect is well known in the oceanographic context and is attributed to the excitation of the so-called collective instability. In this work, we build on the results of Brown et al. and of Traxler et al. to determine the conditions under which the collective instability may be expected. We find that it is only relevant in stellar regions that have a relatively large Prandtl number (the ratio of the kinematic viscosity to the thermal diffusivity), O({10}-3) or larger. This implies that the collective instability cannot occur in main-sequence stars, where the Prandtl number is always much smaller than this (except in the outer layers of surface convection zones, where fingering is irrelevant anyway). It could in principle be excited in regions of high electron degeneracy, during He core flash, or in the interiors of white dwarfs. We discuss the implications of our findings for these objects, from both a theoretical and an observational point of view.

  11. High-Speed, High-Temperature Finger Seal Test Evaluated

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2003-01-01

    A finger seal, designed and fabricated by Honeywell Engines, Systems and Services, was tested at the NASA Glenn Research Center at surface speeds up to 1200 ft/s, air temperatures up to 1200 F, and pressures across the seal of 75 psid. These are the first test results obtained with NASA s new High-Temperature, High-Speed Turbine Seal Test Rig (see the photograph). The finger seal is an innovative design recently patented by AlliedSignal Engines, which has demonstrated considerably lower leakage than commonly used labyrinth seals and is considerably cheaper than brush seals. The cost to produce finger seals is estimated to be about half of the cost to produce brush seals. Replacing labyrinth seals with fingers seals at locations that have high-pressure drops in gas turbine engines, typically main engine and thrust seals, can reduce air leakage at each location by 50 percent or more. This directly results in a 0.7- to 1.4-percent reduction in specific fuel consumption and a 0.35- to 0.7-percent reduction in direct operating costs . Because the finger seal is a contacting seal, this testing was conducted to address concerns about its heat generation and life capability at the higher speeds and temperatures required for advanced engines. The test results showed that the seal leakage and wear performance are acceptable for advanced engines.

  12. Fluid-driven fingering instability of a confined elastic meniscus

    NASA Astrophysics Data System (ADS)

    Biggins, John S.; Wei, Z.; Mahadevan, L.

    2015-05-01

    When a fluid is pumped into a cavity in a confined elastic layer, at a critical pressure, destabilizing fingers of fluid invade the elastic solid along its meniscus (Saintyves B. et al., Phys. Rev. Lett., 111 (2013) 047801). These fingers occur without fracture or loss of adhesion and are reversible, disappearing when the pressure is decreased. We develop an asymptotic theory of pressurized highly elastic layers trapped between rigid bodies in both rectilinear and circular geometries, with predictions for the critical fluid pressure for fingering, and the finger wavelength. Our results are in good agreement with recent experimental observations of this elastic interfacial instability in a radial geometry. Our theory also shows that, perhaps surprisingly, this lateral-pressure-driven instability is analogous to a transverse-displacement-driven instability of the elastic layer. We verify these predictions by using non-linear finite-element simulations on the two systems which show that in both cases the fingering transition is first order (sudden) and hence has a region of bistability.

  13. Traumatic Finger Injuries: What the Orthopedic Surgeon Wants to Know.

    PubMed

    Wieschhoff, Ged G; Sheehan, Scott E; Wortman, Jeremy R; Dyer, George S M; Sodickson, Aaron D; Patel, Ketan I; Khurana, Bharti

    2016-01-01

    Traumatic finger injuries account for a substantial number of emergency visits every year. Imaging plays an important role in diagnosis and in directing management of these injuries. Although many injuries can be managed conservatively, some require more invasive interventions to prevent complications and loss of function. Accurate diagnosis of finger injuries can often be difficult, given the complicated soft-tissue anatomy of the hand and the diverse spectrum of injuries that can occur. To best serve the patient and the treating physician, radiologists must have a working knowledge of finger anatomy, the wide array of injury patterns that can occur, the characteristic imaging findings of different finger injuries, and the most appropriate treatment options for each type of injury. This article details the intricate anatomy of the hand as it relates to common finger injuries, illustrates the imaging findings of a range of injuries, presents optimal imaging modalities and imaging parameters for the diagnosis of different injury types, and addresses which findings have important management implications for the patient and the orthopedic surgeon. With this fund of knowledge, radiologists will be able to recommend the most appropriate imaging studies, make accurate diagnoses, convey clinically relevant imaging findings to the referring physician, and suggest appropriate follow-up examinations. In this way, the radiologist will help improve patient care and outcomes. Online supplemental material is available for this article. (©)RSNA, 2016. PMID:27399238

  14. RNA binding by the Wilms tumor suppressor zinc finger proteins.

    PubMed Central

    Caricasole, A; Duarte, A; Larsson, S H; Hastie, N D; Little, M; Holmes, G; Todorov, I; Ward, A

    1996-01-01

    The Wilms tumor suppressor gene WT1 is implicated in the ontogeny of genito-urinary abnormalities, including Denys-Drash syndrome and Wilms tumor of the kidney. WT1 encodes Kruppel-type zinc finger proteins that can regulate the expression of several growth-related genes, apparently by binding to specific DNA sites located within 5' untranslated leader regions as well as 5' promoter sequences. Both WT1 and a closely related early growth response factor, EGR1, can bind the same DNA sequences from the mouse gene encoding insulin-like growth factor 2 (Igf-2). We report that WT1, but not EGR1, can bind specific Igf-2 exonic RNA sequences, and that the zinc fingers are required for this interaction. WT1 zinc finger 1, which is not represented in EGR1, plays a more significant role in RNA binding than zinc finger 4, which does have a counterpart in EGR1. Furthermore, the normal subnuclear localization of WT1 proteins is shown to be RNase, but not DNase, sensitive. Therefore, WT1 might, like the Kruppel-type zinc finger protein TFIIIA, regulate gene expression by both transcriptional and posttranscriptional mechanisms. Images Fig. 1 Fig. 2 Fig. 3 PMID:8755514

  15. Finger Vein Recognition Based on Personalized Weight Maps

    PubMed Central

    Yang, Gongping; Xiao, Rongyang; Yin, Yilong; Yang, Lu

    2013-01-01

    Finger vein recognition is a promising biometric recognition technology, which verifies identities via the vein patterns in the fingers. Binary pattern based methods were thoroughly studied in order to cope with the difficulties of extracting the blood vessel network. However, current binary pattern based finger vein matching methods treat every bit of feature codes derived from different image of various individuals as equally important and assign the same weight value to them. In this paper, we propose a finger vein recognition method based on personalized weight maps (PWMs). The different bits have different weight values according to their stabilities in a certain number of training samples from an individual. Firstly we present the concept of PWM, and then propose the finger vein recognition framework, which mainly consists of preprocessing, feature extraction, and matching. Finally, we design extensive experiments to evaluate the effectiveness of our proposal. Experimental results show that PWM achieves not only better performance, but also high robustness and reliability. In addition, PWM can be used as a general framework for binary pattern based recognition. PMID:24025556

  16. The biometric recognition on contactless multi-spectrum finger images

    NASA Astrophysics Data System (ADS)

    Kang, Wenxiong; Chen, Xiaopeng; Wu, Qiuxia

    2015-01-01

    This paper presents a novel multimodal biometric system based on contactless multi-spectrum finger images, which aims to deal with the limitations of unimodal biometrics. The chief merits of the system are the richness of the permissible texture and the ease of data access. We constructed a multi-spectrum instrument to simultaneously acquire three different types of biometrics from a finger: contactless fingerprint, finger vein, and knuckleprint. On the basis of the samples with these characteristics, a moderate database was built for the evaluation of our system. Considering the real-time requirements and the respective characteristics of the three biometrics, the block local binary patterns algorithm was used to extract features and match for the fingerprints and finger veins, while the Oriented FAST and Rotated BRIEF algorithm was applied for knuckleprints. Finally, score-level fusion was performed on the matching results from the aforementioned three types of biometrics. The experiments showed that our proposed multimodal biometric recognition system achieves an equal error rate of 0.109%, which is 88.9%, 94.6%, and 89.7% lower than the individual fingerprint, knuckleprint, and finger vein recognitions, respectively. Nevertheless, our proposed system also satisfies the real-time requirements of the applications.

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

    PubMed Central

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

    2016-01-01

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

  18. Development of cylindrical-type finger force measuring system using force sensors and its characteristics evaluation

    NASA Astrophysics Data System (ADS)

    Kim, Hyeon-Min; Yoon, Joungwon; Shin, Hee-Suk; Kim, Gab-Soon

    2012-02-01

    Some patients cannot use their hands because of the paralysis of their fingers. Their fingers can recover with rehabilitative training, and the extent of rehabilitation can be judged by grasping a cylindrical-object with their fingers. At present, the cylindrical-object used in hospitals is only a plastic cylinder, which cannot measure grasping force of the fingers. Therefore, doctors must judge the extent of rehabilitation by watching patients' fingers as they grasp the plastic cylinder. In this paper, the development of two cylindrical-type finger force measuring systems with four force sensors for left hand and right hand were developed. The developed finger force measuring system can measure the grasping force of patients' each finger (forefinger, middle finger, ring finger and little finger), and the measured results could be used to judge the rehabilitation extent of a finger patient. The grasping force tests of men and women were performed using the developed cylindrical-type finger force measuring systems. The tests confirm that the average finger forces of right hand and left hand for men were about 194 N and 179 N, and for women, 108 N and 95 N.

  19. Index and ring finger ratio--a morphologic sex determinant in South-Indian children.

    PubMed

    Kanchan, Tanuj; Pradeep Kumar, G

    2010-12-01

    To investigate the sexual dimorphism of index and ring finger ratio in South Indian children. The index finger length (IFL) and the ring finger length (RFL) were measured in 350 subjects aged between 2 and 12 years using a steel measuring tape. The index and ring finger ratio was computed by dividing index finger length by ring finger length. The data obtained were analyzed statistically using SPSS, version 11.0. Mean RFL was greater than mean IFL in both males and females. The mean ring finger length was longer in males than females and mean index finger length longer in females than males. However, these sex differences observed for index and ring finger length were not significant in both hands. Statistically significant sex differences were observed from the derived index and ring finger ratio. The mean index and ring finger ratio was found to be higher in females than males. Significant correlation was found between age and index and ring finger lengths. Index and ring finger ratio however, did not show any significant correlation with age. This study suggests that among South-Indian children, the index and ring finger ratio of 0.97 and less is indicative of male, and a ratio of more than 0.97 is indicative of female sex. The ratio can be a useful sex indicator irrespective of the age of the individual. PMID:20369311

  20. Targeted Mutagenesis in Zebrafish Using Customized Zinc Finger Nucleases

    PubMed Central

    Foley, Jonathan E.; Maeder, Morgan L.; Pearlberg, Joseph; Joung, J. Keith; Peterson, Randall T.; Yeh, Jing-Ruey J.

    2009-01-01

    Zebrafish mutants have traditionally been obtained using random mutagenesis or retroviral insertions, methods that cannot be targeted to a specific gene and require laborious gene mapping and sequencing. Recently, we and others have shown that customized zinc finger nucleases (ZFNs) can introduce targeted frame-shift mutations with high efficiency, thereby enabling directed creation of zebrafish gene mutations. Here we describe a detailed protocol for constructing ZFN expression vectors, for generating and introducing ZFN-encoding RNAs into zebrafish embryos, and for identifying ZFN-generated mutations in targeted genomic sites. All of our vectors and methods are compatible with previously described Zinc Finger Consortium reagents for constructing engineered zinc finger arrays. Using these methods, zebrafish founders carrying targeted mutations can be identified within four months. PMID:20010934

  1. Initial results of finger imaging using photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  2. Prognostic factors on survival rate of fingers replantation

    PubMed Central

    Lima, José Queiroz; Carli, Alberto De; Nakamoto, Hugo Alberto; Bersani, Gustavo; Crepaldi, Bruno Eiras; de Rezende, Marcelo Rosa

    2015-01-01

    Objective: To evaluate the factors that influence the survival rate of replantation and revascularization of the thumb and/or fingers. Methods: We included fifty cases treated in our department from May 2012 to October 2013 with total or partial finger amputations, which had blood perfusion deficit and underwent vascular anastomosis. The parameters evaluated were: age, gender, comorbidities, trauma, time and type of ischemia, mechanism, the injured area, number of anastomosed vessels and use of vein grafts. The results were statistically analyzed and type I error value was set at p <0.05 . Results: Fifty four percent of the 50 performed replantation survived. Of 15 revascularizations performed, the survival rate was 93.3%. The only factor that affected the survival of the amputated limb was the necessity of venous anastomosis. Conclusion: We could not establish contraindications or absolute indications for the replantation and revascularization of finger amputations in this study. Level of Evidence III, Retropective Study. PMID:26327788

  3. Arthropathy, ankylosing spondylitis, and clubbing of fingers in ulcerative colitis

    PubMed Central

    Jalan, K. N.; Prescott, R. J.; Walker, R. J.; Sircus, W.; McManus, J. P. A.; Card, W. I.

    1970-01-01

    In a retrospective study of 399 patients with ulcerative colitis, 27 patients had colitic arthritis, 17 had ankylosing spondylitis, and 20 had clubbing of the fingers. Colitic arthritis and ankylosing spondylitis were not related to severity, extent of involvement, or duration of colitis. A significant association between colitic arthropathy and other complications of ulcerative colitis, such as pseudopolyposis, perianal disease, eye lesions, skin eruptions, aphthous ulceration, and liver disease has been demonstrated. The outcome of the first referred attack of colitis in the presence of colitic arthritis and ankylosing spondylitis remained uninfluenced. Clubbing of fingers was related to severity, extent of involvement, and length of the history of colitis. A significant association between clubbing of the fingers and carcinoma of the colon, pseudopolyposis, toxic dilatation, and arthropathy has been shown. The frequency of surgical intervention in patients with clubbing was higher but the overall mortality was not significantly different from the patients without clubbing. PMID:5473606

  4. High-Speed, High-Temperature Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.; Kumar, Arun; Delgado, Irebert R.

    2002-01-01

    Finger seals have significantly lower leakage rates than conventional labyrinth seals used in gas turbine engines and are expected to decrease specific fuel consumption by over 1 percent and to decrease direct operating cost by over 0.5 percent. Their compliant design accommodates shaft growth and motion due to thermal and dynamic loads with minimal wear. The cost to fabricate these finger seals is estimated to be about half the cost to fabricate brush seals. A finger seal has been tested in NASA's High Temperature, High Speed Turbine Seal Test Rig at operating conditions up to 1200 F, 1200 ft/s, and 75 psid. Static, performance and endurance test results are presented. While seal leakage and wear performance are acceptable, further design improvements are needed to reduce the seal power loss.

  5. Regulation of cancer stem cells by RING finger ubiquitin ligases

    PubMed Central

    Sun, Xiao-Hong

    2014-01-01

    Like normal stem cells, cancer stem cells (CSCs) are capable of self-renewal, either by symmetric or asymmetric cell division. They have the exclusive ability to reproduce malignant tumors indefinitely, and to confer resistance in response to radiation or chemotherapy. The ubiquitin modification system plays various roles in physiology and pathology. The key component for the specificity of this system is ubiquitin ligases (E3s). Of these E3s, the majority are RING finger proteins. Many RING finger E3s, such as the Cullin1-Skp1-F-box protein (SCF) E3s, CBL, BRCA1, MDM2 and von Hippel-Lindau tumour suppressor (VHL), are crucial in the regulation of cell-cycle progression and cell differentiation. As a result, many RING finger E3s are implicated in the positive and negative regulation of CSC maintenance. This review summarizes current knowledge in this research field. PMID:27358852

  6. Finger Pricking and Pain: A Never Ending Story

    PubMed Central

    Heinemann, Lutz

    2008-01-01

    Without finger pricking, no self-measurement of blood glucose (SMBG) is possible. However, the number of scientific studies dealing with this topic, which is highly relevant for patients, is surprisingly small. This is in sharp contrast to the number of papers about blood glucose meters and SMBG in general. This article highlights a number of aspects that are relevant when it comes to finger pricking and pain. There is a clear improvement in the technology employed in the many different lancing devices that are on the market nowadays; however, no good head-to-head comparison study has been performed to date. The invention of novel devices for finger pricking will most likely bring more attention to this topic. PMID:19885279

  7. Finger sudorometry and assessment of the sudomotor drive.

    PubMed

    Satchell, P; Ware, S; Barron, J; Tuck, R

    1994-08-01

    Sudorometry of the finger was carried out using the ventilated capsule method, the aim being to use the level of relative humidity within the sudorometer as an indirect measure of the sudomotor drive. Subjects inserted a finger through a diaphragm of a finger-shaped, temperature-controlled chamber which also contained the humidity sensor. Manoeuvres known to alter the sudomotor drive produced changes in chamber humidity. The relative humidity within the sudorometer became constant after local anaesthesia of the digital nerves and after upper limb sympathectomy, suggesting that fluctuations in the sudorometer output were dependent upon an intact autonomic nervous system. In an environment in which temperature was controlled and arousal effects from the process of measurement were minimised, chamber humidity always increased during a Stroop test, providing a rapid means of indirectly assessing sudomotor drive mechanisms. PMID:7823624

  8. Effect of transcranial magnetic stimulation on force of finger pinch

    NASA Astrophysics Data System (ADS)

    Odagaki, Masato; Fukuda, Hiroshi; Hiwaki, Osamu

    2009-04-01

    Transcranial magnetic stimulation (TMS) is used to explore many aspects of brain function, and to treat neurological disorders. Cortical motor neuronal activation by TMS over the primary motor cortex (M1) produces efferent signals that pass through the corticospinal tracts. Motor-evoked potentials (MEPs) are observed in muscles innervated by the stimulated motor cortex. TMS can cause a silent period (SP) following MEP in voluntary electromyography (EMG). The present study examined the effects of TMS eliciting MEP and SP on the force of pinching using two fingers. Subjects pinched a wooden block with the thumb and index finger. TMS was applied to M1 during the pinch task. EMG of first dorsal interosseous muscles and pinch forces were measured. Force output increased after the TMS, and then oscillated. The results indicated that the motor control system to keep isotonic forces of the muscles participated in the finger pinch was disrupted by the TMS.

  9. Finger Vein Recognition Based on a Personalized Best Bit Map

    PubMed Central

    Yang, Gongping; Xi, Xiaoming; Yin, Yilong

    2012-01-01

    Finger vein patterns have recently been recognized as an effective biometric identifier. In this paper, we propose a finger vein recognition method based on a personalized best bit map (PBBM). Our method is rooted in a local binary pattern based method and then inclined to use the best bits only for matching. We first present the concept of PBBM and the generating algorithm. Then we propose the finger vein recognition framework, which consists of preprocessing, feature extraction, and matching. Finally, we design extensive experiments to evaluate the effectiveness of our proposal. Experimental results show that PBBM achieves not only better performance, but also high robustness and reliability. In addition, PBBM can be used as a general framework for binary pattern based recognition. PMID:22438735

  10. Interfacial instabilities and fingering formation in Hele-Shaw flow

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Jun

    1996-10-01

    The interfacial instability of Hele-Shaw flow has been a crucial issue for the understanding of the pattern formation of viscous fingers in a Hele-Shaw cell. By using a unified asymptotic approach, we derive two different types of instability mechanisms for slightly' time-dependent finger solutions; namely, (i) the global-trapped-wave (GTW) instability; and (ii) the zero-frequency (null-f) instability. On the basis of these instability mechanisms, the selection of viscous finger formation is clarified; the apparent contradiction between the previous linearstability analysis by Tanveer (1987, Phys. Fluid 30, 1589) and others and the numerical simulations by DeGregoria & Schwartz (1986, J. Fluid Mech. 164, 383)and the experimental evidence is reconciled.

  11. Spatial proximity of the HIV-1 nucleocapsid protein zinc fingers investigated by time-resolved fluorescence and fluorescence resonance energy transfer.

    PubMed

    Mély, Y; Jullian, N; Morellet, N; De Rocquigny, H; Dong, C Z; Piémont, E; Roques, B P; Gérard, D

    1994-10-11

    The three-dimensional structure of peptides encompassing the two zinc-saturated finger motifs of the nucleocapsid protein NCp7 of HIV-1 has been reported by several groups. Whereas the folded structures of the finger motifs were in good agreement, discrepancies existed concerning their spatial relationship since the fingers were found either close to each other [Morellet, N., Jullian, N., De Rocquigny, H., Maigret, B., Darlix, J. L., & Roques, B. P. (1992) Embo J. 11, 3059-3065] or independently folded [Omichinski, J. G., Clore, G. M., Sakaguchi, K., Appella, E., & Gronenborn, A. M. (1991) FEBS Lett. 292, 25-30, Summers, M. F., Henderson, L. E., Chance, M. R., Bess, J. W., Jr., South, T. L., Blake, P. R., Sagi, I., Perez-Alvarado, G., Sowder, R.C., III, Hare, D.R., & Arthur, L. O. (1992) Protein Sci. 1, 563-574]. As in the interacting finger model, Phe16 in the NH2-terminal finger and Trp37 in the COOH-terminal finger were found to be spatially close, the fluorescence properties of the aromatic residues at positions 16 and 37 in the wild-type and two conservatively substituted (12-53) NCp7 peptides were investigated and compared with those of three negative control derivatives where the finger motifs were not in close contact. Direct distance measurements by Tyr-Trp fluorescence resonance energy transfer of the former derivatives yielded a 7-12 A interchromophore distance range which is clearly inconsistent with the 12.5-18 A range measured for the negative controls and thus a random orientation of the zinc finger motifs.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7918429

  12. Distant functional connectivity for bimanual finger coordination declines with aging: an fMRI and SEM exploration

    PubMed Central

    Kiyama, Sachiko; Kunimi, Mitsunobu; Iidaka, Tetsuya; Nakai, Toshiharu

    2014-01-01

    Although bimanual finger coordination is known to decline with aging, it still remains unclear how exactly the neural substrates underlying the coordination differ between young and elderly adults. The present study focused on: (1) characterization of the functional connectivity within the motor association cortex which is required for successful bimanual finger coordination, and (2) to elucidate upon its age-related decline. To address these objectives, we utilized functional magnetic resonance imaging (fMRI) in combination with structural equation modeling (SEM). This allowed us to compare functional connectivity models between young and elderly age groups during a visually guided bimanual finger movement task using both stable in-phase and complex anti-phase modes. Our SEM exploration of functional connectivity revealed significant age-related differences in connections surrounding the PMd in the dominant hemisphere. In the young group who generally displayed accurate behavior, the SEM model for the anti-phase mode exhibited significant connections from the dominant PMd to the non-dominant SPL, and from the dominant PMd to the dominant S1. However, the model for the elderly group's anti-phase mode in which task performance dropped, did not exhibit significant connections within the aforementioned regions. These results suggest that: (1) the dominant PMd acts as an intermediary to invoke intense intra- and inter-hemispheric connectivity with distant regions among the higher motor areas including the dominant S1 and the non-dominant SPL in order to achieve successful bimanual finger coordination, and (2) the distant connectivity among the higher motor areas declines with aging, whereas the local connectivity within the bilateral M1 is enhanced for the complex anti-phase mode. The latter may underlie the elderly's decreased performance in the complex anti-phase mode of the bimanual finger movement task. PMID:24795606

  13. Custom-Made Finger Guard to Prevent Wire-Stick Injury to the Operator's Finger while Performing Intermaxillary Fixation

    PubMed Central

    Kumaresan, Ramesh; Ponnusami, Karthikeyan; Karthikeyan, Priyadarshini

    2014-01-01

    The treatment of maxillofacial fractures involves different methods from bandages and splinting to methods of open reduction and internal fixation and usually requires control of the dental occlusion with the help of intermaxillary fixation (IMF). Different wiring techniques have been used to aid in IMF including placement of custom-made arch bars, eyelet etc. However, these wiring techniques are with a constant danger of trauma to the surgeon's fingers by their sharp ends. Though there exist a variety of commercially available barrier products and customized techniques to prevent wire-stick injury, cost factor, touch sensitivity, and comfort aspect restrain their acquirement and exploit. This technical note describes the construction of a simple and economical finger guard made of soft thermoplastic material that provides an added protection to fingers from wire-stick type injuries, and its flexible nature permits a comfortable finger flexion movement and acceptable touch sensitivity. This is a simple, economical, reusable puncture, and cut-resistance figure guard by which we can avoid wire-stick type injury to the operator's fingers during wiring technique. PMID:25383158

  14. A comparison of thermoregulatory responses to exercise between mass-matched groups with large differences in body fat.

    PubMed

    Dervis, Sheila; Coombs, Geoff B; Chaseling, Georgia K; Filingeri, Davide; Smoljanic, Jovana; Jay, Ollie

    2016-03-15

    We sought to determine 1) the influence of adiposity on thermoregulatory responses independently of the confounding biophysical factors of body mass and metabolic heat production (Hprod); and 2) whether differences in adiposity should be accounted for by prescribing an exercise intensity eliciting a fixed Hprod per kilogram of lean body mass (LBM). Nine low (LO-BF) and nine high (HI-BF) body fat males matched in pairs for total body mass (TBM; LO-BF: 88.7 ± 8.4 kg, HI-BF: 90.1 ± 7.9 kg; P = 0.72), but with distinctly different percentage body fat (%BF; LO-BF: 10.8 ± 3.6%; HI-BF: 32.0 ± 5.6%; P < 0.001), cycled for 60 min at 28.1 ± 0.2°C, 26 ± 8% relative humidity (RH), at a target Hprod of 1) 550 W (FHP trial) and 2) 7.5 W/kg LBM (LBM trial). Changes in rectal temperature (ΔTre) and local sweat rate (LSR) were measured continuously while whole body sweat loss (WBSL) and net heat loss (Hloss) were estimated over 60 min. In the FHP trial, ΔTre (LO-BF: 0.66 ± 0.21°C, HI-BF: 0.87 ± 0.18°C; P = 0.02) was greater in HI-BF, whereas mean LSR (LO-BF 0.52 ± 0.19, HI-BF 0.43 ± 0.15 mg·cm(-2)·min(-1); P = 0.19), WBSL (LO-BF 586 ± 82 ml, HI-BF 559 ± 75 ml; P = 0.47) and Hloss (LO-BF 1,867 ± 208 kJ, HI-BF 1,826 ± 224 kJ; P = 0.69) were all similar. In the LBM trial, ΔTre (LO-BF 0.82 ± 0.18°C, HI-BF 0.54 ± 0.19°C; P < 0.001), mean LSR (LO-BF 0.59 ± 0.20, HI-BF 0.38 ± 0.12 mg·cm(-2)·min(-1); P = 0.04), WBSL (LO-BF 580 ± 106 ml, HI-BF 381 ± 68 ml; P < 0.001), and Hloss (LO-BF 1,884 ± 277 kJ, HI-BF 1,341 ± 184 kJ; P < 0.001) were all greater at end-exercise in LO-BF. In conclusion, high %BF individuals demonstrate a greater ΔTre independently of differences in mass and Hprod, possibly due to a lower mean specific heat capacity or impaired sudomotor control. However, thermoregulatory responses of groups with different adiposity levels should not be compared using a fixed Hprod in watts per kilogram lean body mass. PMID:26702025

  15. Continuous non-invasive finger blood pressure monitoring in children.

    PubMed

    Tanaka, H; Thulesius, O; Yamaguchi, H; Mino, M; Konishi, K

    1994-06-01

    We evaluated the performance of continuous non-invasive finger arterial pressure measurement using the volume-clamp technique (Finapres). This study was designed to compare finger arterial pressure with brachial blood pressure estimated by the auscultatory method in 217 children (90 boys and 127 girls) aged 4-16 years and in 38 adults (aged 18-45 years). Finger and brachial artery pressure readings were obtained consecutively from the ipsilateral side in the supine position. Finger arterial pressure waveforms were recorded in all children except 4 with small and thin fingers. There was good agreement for systolic pressure with only a slight underestimation of 1.9 mmHg and 5.1 mmHg lower for diastolic pressure. This difference most probably reflects inaccuracy of the auscultatory cuff method rather than an error in the Finapres. There was large inter-individual variability in Finapres recordings which might be due to differences in vasomotor tone, as demonstrated by systolic amplification in 5 patients with anorexia. However, Finapres showed a small within-subject variability (3.8 mmHg for systolic and 4.1 mmHg for diastolic pressure) determined in 5 patients during phenylephrine infusion, and as good reproducibility as the auscultatory method. These results suggest that finger arterial pressure measurement in children older than 6 years of age has similar accuracy as that in adults, and that this method is useful for clinical applications in children, especially for the non-invasive evaluation of autonomic control and cardiovascular reflexes involving transient and rapid blood pressure changes. PMID:7919764

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

    PubMed Central

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

    2015-01-01

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

  17. Motor equivalence during multi-finger accurate force production

    PubMed Central

    Mattos, Daniela; Schöner, Gregor; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2014-01-01

    We explored stability of multi-finger cyclical accurate force production action by analysis of responses to small perturbations applied to one of the fingers and inter-cycle analysis of variance. Healthy subjects performed two versions of the cyclical task, with and without an explicit target. The “inverse piano” apparatus was used to lift/lower a finger by 1 cm over 0.5 s; the subjects were always instructed to perform the task as accurate as they could at all times. Deviations in the spaces of finger forces and modes (hypothetical commands to individual fingers) were quantified in directions that did not change total force (motor equivalent) and in directions that changed the total force (non-motor equivalent). Motor equivalent deviations started immediately with the perturbation and increased progressively with time. After a sequence of lifting-lowering perturbations leading to the initial conditions, motor equivalent deviations were dominating. These phenomena were less pronounced for analysis performed with respect to the total moment of force with respect to an axis parallel to the forearm/hand. Analysis of inter-cycle variance showed consistently higher variance in a subspace that did not change the total force as compared to the variance that affected total force. We interpret the results as reflections of task-specific stability of the redundant multi-finger system. Large motor equivalent deviations suggest that reactions of the neuromotor system to a perturbation involve large changes of neural commands that do not affect salient performance variables, even during actions with the purpose to correct those salient variables. Consistency of the analyses of motor equivalence and variance analysis provides additional support for the idea of task-specific stability ensured at a neural level. PMID:25344311

  18. Comparison of Thermoregulatory Devices Used during Anesthesia of C57BL/6 Mice and Correlations between Body Temperature and Physiologic Parameters

    PubMed Central

    Caro, Adam C; Hankenson, F Claire; Marx, James O

    2013-01-01

    General anesthesia affects several body systems, including thermoregulation. Decreased body temperature during anesthesia has potential negative effects, including delayed recovery to consciousness. Thermoregulatory support devices are used to maintain temperature in anesthetized rodents. We analyzed 2 novel thermoregulatory devices, thermogenic gel packs and reflective foils, to compare their effectiveness in maintaining temperatures with that of a standard circulating-warm–water blanket (CWWB) in C57BL/6 mice. Mice were grouped randomly: control (no thermal support), reflective foil, gel pack, gel pack plus reflective foil, CWWB on medium setting, CWWB on high setting, and CWWB on high setting plus reflective foil. Mice were anesthetized with isoflurane for 30 min, and temperature and heart and respiratory rates were monitored. Results indicated that the temperatures of mice with reflective foil only (start temperature, 36.2 ± 0.38 °C; end temperature, 28.8 ± 0.78 °C) did not differ significantly from those of control mice; however, the inclusion of foil heightened thermogenic properties when combined with other devices. Thermogenic gel packs and CWWB on high setting, both with and without reflective foil, caused significant temperature increases (that is, 1.6 °C to 4.4 °C) in mice. CWWB on medium setting (blanket temperature, 37.5 °C) maintained mice at temperatures within 1 °C of the 36.1 °C baseline. Strong correlations existed between temperature, heart and respiratory rates, and recovery time to consciousness. This information provides guidance regarding the use of thermoregulatory devices in anesthetized rodents and demonstrates the effect of maintaining a consistent core temperature on physiologic parameters. PMID:24041214

  19. Voluntary drinking versus imposed drinking in the methodology of investigations about the drinking-induced thermoregulatory sweating

    PubMed Central

    Hosseinlou, Abdollah; Khamnei, Saeed; Zamanlu, Masumeh

    2014-01-01

    Studies have shown that dehydrated humans or animals in a warm environment begin to sweat within seconds to minutes after drinking. This phenomenon is one of the drinking-induced thermoregulatory responses; being investigated from different aspects. Our objective is to show the difference of voluntary drinking and imposed drinking in the methodology of these experiments. Six healthy subjects 23.7 ± 0.6 yr old and 80.7 ± 5.7 kg wt were dehydrated by performing mild exercise (ergometer cycling) in a hot and humid chamber (38-40°C, 20-28% relative humidity). We incorporated two protocols: after dehydration, subjects were allowed to drink water with 1) imposed volumes of 1, 3, 5 ml/kg and 2) voluntary volumes; on four separate days. The sweating rate was measured on the forehead area before and after drinking. Sweating increased markedly just a few minutes after the onset of drinking. The mean sweat rates of the imposed volumes of 1, 3, 5 ml/Kg were 0.33 ± 0.15, 0.31 ± 0.17, 0.47 ± 0.21 respectively and for the voluntary volume it was 0.54 ± 0.19. The mean intake in the voluntary trial was 6.58 ± 1.14 ml/Kg, more than the imposed volume of 5 ml/Kg. The trend of the rate of the sweating response in the imposed trials was distinct from the response in the voluntary trial. Conclusion: There exists a difference between voluntary drinking and imposed drinking in the sweating response that follows rehydration. So it is suggested to use the methods of voluntary drinking in the investigations of this phenomenon, to reveal the natural events that happen in the actual circumstances. PMID:25419429

  20. Daily variations in the thermoregulatory behaviors of naked neck broilers in an equatorial semi-arid environment

    NASA Astrophysics Data System (ADS)

    de Queiroz, João Paulo Araújo Fernandes; de Souza, João Batista Freire; de Lima, Hiagos Felipe Ferreira; de Oliveira Costa, Monik Kelly; de Macedo Costa, Leonardo Lelis; de Arruda, Alex Martins Varela

    2014-08-01

    The aim of this study was to evaluate the daily variations in the thermoregulatory behavior of 4- to 6-week-old naked neck broilers (Label Rouge) in an equatorial semi-arid environment. A total of 220 birds were monitored for 5 days starting at 0600 hours and ending at 1800 hours. The period of observation was divided into classes of hours ( C H). The observed behaviors were as follows: feed and water intake, wing-spreading, sitting or lying, and beak-opening. A total of 14,300 behavioral data values were registered. In C H 2 (0900 hours to 1100 hours) and 3 (1200 hours to 1500 hours), the greatest average body surface temperature was recorded (34.67 ± 0.25 °C and 35.12 ± 0.22 °C, respectively). The C H had an effect on the exhibition of all behaviors with the exception of the water intake behavior. Feed intake was more frequent in C H 1 (0600 hours to 0800 hours) and 4 (1600 hours to 1800 hours). In C H 2 and 3, the highest frequency of sitting or lying behavior was observed. Beak-opening and wing-spreading behaviors occurred more frequently in C H 3 where the body surface temperature (35.12 ± 0.22 °C), radiant heat load (519.38 ± 2.22 W m-2), and enthalpy (82.74 ± 0.36 kJ kg-1 of dry air) reached maximum recorded averages. Thus, it can be concluded that naked neck broilers adjust their behavior in response to daily variations in the thermal environment. Wing-spreading and beak-opening behaviors are important adaptive responses to the thermal challenges posed by the equatorial semi-arid environment.