Investigating the relationship between energy expenditure, walking speed and angle of turning in humans.

Directory of Open Access Journals (Sweden)

M A McNarry

Full Text Available Recent studies have suggested that changing direction is associated with significant additional energy expenditure. A failure to account for this additional energy expenditure of turning has significant implications in the design and interpretation of health interventions. The purpose of this study was therefore to investigate the influence of walking speed and angle, and their interaction, on energy expenditure in 20 healthy adults (7 female; 28±7 yrs. On two separate days, participants completed a turning protocol at one of 16 speed- (2.5, 3.5, 4.5, 5.5 km∙h-1 and angle (0, 45, 90, 180° combinations, involving three minute bouts of walking, interspersed by three minutes seated rest. Each condition involved 5 m of straight walking before turning through the pre-determined angle with the speed dictated by a digital, auditory metronome. Tri-axial accelerometry and magnetometry were measured at 60 Hz, in addition to gas exchange on a breath-by-breath basis. Mixed models revealed a significant main effect for speed (F = 121.609, P < 0.001 and angle (F = 19.186, P < 0.001 on oxygen uptake ([Formula: see text] and a significant interaction between these parameters (F = 4.433, P < 0.001. Specifically, as speed increased, [Formula: see text] increased but significant increases in [Formula: see text] relative to straight line walking were only observed for 90° and 180° turns at the two highest speeds (4.5 and 5.5 km∙hr-1. These findings therefore highlight the importance of accounting for the quantity and magnitude of turns completed when estimating energy expenditure and have significant implications within both sport and health contexts.

Teste de caminhada e rendimento escolar em crianças respiradoras bucais Walk test and school performance in mouth-breathing children

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Ana Paula Dias Vilas Boas

2013-04-01

Full Text Available Nas últimas décadas, vários trabalhos sobre respiração bucal (RB têm surgido na literatura; em contrapartida, pouco se conhece sobre vários aspectos desta síndrome, incluindo gravidade, repercussões sobre o rendimento físico e escolar. OBJETIVO: Comparar o rendimento físico pelo teste de caminhada de seis minutos (TC6' e rendimento escolar de crianças e adolescentes com RB e respiradores nasais (RN. MÉTODO: Estudo de corte transversal descritivo e prospectivo em crianças RB e RN que foram submetidas ao TC6' e avaliação do rendimento escolar. RESULTADOS: Foram incluídos 156 escolares, 87 meninas (60 RN e 27 RB e 69 meninos (44 RN e 25 RB. Foram analisadas variáveis durante o TC6': frequência cardíaca (FC, frequência respiratória, saturação periférica de oxigênio, distância percorrida em seis minutos e escala de Borg modificada. Todos os valores das variáveis estudadas foram estatisticamente diferentes entre os grupos RB e RN, com exceção do rendimento escolar e FC no TC6'. CONCLUSÃO: A RB afeta o rendimento físico e não o rendimento escolar, sendo observado padrão alterado no TC6' no grupo RB. Uma vez que os RB desse estudo foram classificados como não graves outros estudos comparando as variáveis de rendimento escolar e TC6' são necessários para o melhor entendimento do processo dos desempenhos físico e escolar em crianças com RB.In recent decades, many studies on mouth breathing (MB have been published; however, little is known about many aspects of this syndrome, including severity, impact on physical and academic performances. OBJECTIVE: Compare the physical performance in a six minutes walk test (6MWT and the academic performance of MB and nasal-breathing (NB children and adolescents. METHOD: This is a descriptive, cross-sectional, and prospective study with MB and NB children submitted to the 6MWT and scholar performance assessment. RESULTS: We included 156 children, 87 girls (60 NB and 27 MB and 69

Medical Issues: Breathing

Science.gov (United States)

... Information Packets Equipment Pool Living With SMA Medical Issues Palliative Breathing Orthopedics Nutrition Equipment Daily Life At ... curesma.org > support & care > living with sma > medical issues > breathing Breathing Breathing problems are the most common ...

Kidney motion during free breathing and breath hold for MR-guided radiotherapy

International Nuclear Information System (INIS)

Stam, Mette K; Van Vulpen, Marco; Intven, Martijn; Crijns, Sjoerd P M; Lagendijk, Jan J W; Raaymakers, Bas W; Barendrecht, Maurits M; Zonnenberg, Bernard A

2013-01-01

Current treatments for renal cell carcinoma have a high complication rate due to the invasiveness of the treatment. With the MRI-linac it may be possible to treat renal tumours non-invasively with high-precision radiotherapy. This is expected to reduce complications. To deliver a static dose distribution, radiation gating will be used. In this study the reproducibility and efficiency of free breathing gating and a breath hold treatment of the kidney was investigated. For 15 patients with a renal lesion the kidney motion during 2 min of free breathing and 10 consecutive expiration breath holds was studied with 2D cine MRI. The variability in kidney expiration position and treatment efficiency for gating windows of 1 to 20 mm was measured for both breathing patterns. Additionally the time trend in free breathing and the variation in expiration breath hold kidney position with baseline shift correction was determined. In 80% of the patients the variation in expiration position during free breathing is smaller than 2 mm. No clinically relevant time trends were detected. The variation in expiration breath hold is for all patients larger than the free breathing expiration variation. Gating on free breathing is, for gating windows of 1 to 5 mm more efficient than breath hold without baseline correction. When applying a baseline correction to the breath hold it increases the treatment efficiency. The kidney position is more reproducible in expiration free breathing than non-guided expiration breath hold. For small gating windows it is also more time efficient. Since free breathing also seems more comfortable for the patients it is the preferred breathing pattern for MRI-Linac treatments of the kidney. (paper)

Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.

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Yoshiyuki Fukuoka

Full Text Available Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency, breath-by-breath ventilation (V̇E and gas exchange (CO2 output (V̇CO2 and O2 uptake (V̇O2 responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min. The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW was significantly greater than that during sinusoidal cycling (SC, and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward and muscle afferent feedback.

Cardiac autonomic function in patients with diabetes improves with practice of comprehensive yogic breathing program

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Viveka P Jyotsna

2013-01-01

Full Text Available Background: The aim of this study was to observe the effect comprehensive yogic breathing (Sudarshan Kriya Yoga [SKY] and Pranayam had on cardiac autonomic functions in patients with diabetes. Materials and Methods: This is a prospective randomized controlled intervention trial. Cardiac autonomic functions were assessed in 64 diabetics. Patients were randomized into two groups, one group receiving standard therapy for diabetes and the other group receiving standard therapy for diabetes and comprehensive yogic breathing program. Standard therapy included dietary advice, brisk walking for 45 min daily, and administration of oral antidiabetic drugs. Comprehensive yogic breathing program was introduced to the participants through a course of 12 h spread over 3 days. It was an interactive session in which SKY, a rhythmic cyclical breathing, preceded by Pranayam is taught under the guidance of a certified teacher. Cardiac autonomic function tests were done before and after 6 months of intervention. Results: In the intervention group, after practicing the breathing techniques for 6 months, the improvement in sympathetic functions was statistically significant (P 0.04. The change in sympathetic functions in the standard therapy group was not significant (P 0.75.Parasympathetic functions did not show any significant change in either group. When both parasympathetic and sympathetic cardiac autonomic functions were considered, there was a trend toward improvement in patients following comprehensive yogic breathing program (P 0.06. In the standard therapy group, no change in cardiac autonomic functions was noted (P 0.99. Conclusion: Cardiac autonomic functions improved in patients with diabetes on standard treatment who followed the comprehensive yogic breathing program compared to patients who were on standard therapy alone.

DNA breathing dynamics: analytic results for distribution functions of relevant Brownian functionals.

Science.gov (United States)

Bandyopadhyay, Malay; Gupta, Shamik; Segal, Dvira

2011-03-01

We investigate DNA breathing dynamics by suggesting and examining several Brownian functionals associated with bubble lifetime and reactivity. Bubble dynamics is described as an overdamped random walk in the number of broken base pairs. The walk takes place on the Poland-Scheraga free-energy landscape. We suggest several probability distribution functions that characterize the breathing process, and adopt the recently studied backward Fokker-Planck method and the path decomposition method as elegant and flexible tools for deriving these distributions. In particular, for a bubble of an initial size x₀, we derive analytical expressions for (i) the distribution P(t{f}|x₀) of the first-passage time t{f}, characterizing the bubble lifetime, (ii) the distribution P(A|x₀) of the area A until the first-passage time, providing information about the effective reactivity of the bubble to processes within the DNA, (iii) the distribution P(M) of the maximum bubble size M attained before the first-passage time, and (iv) the joint probability distribution P(M,t{m}) of the maximum bubble size M and the time t{m} of its occurrence before the first-passage time. These distributions are analyzed in the limit of small and large bubble sizes. We supplement our analytical predictions with direct numericalsimulations of the related Langevin equation, and obtain a very good agreement in the appropriate limits. The nontrivial scaling behavior of the various quantities analyzed here can, in principle, be explored experimentally.

Walking for Transportation: What do U.S. Adults Think is a Reasonable Distance and Time?

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Watson, Kathleen B; Carlson, Susan A; Humbert-Rico, Tiffany; Carroll, Dianna D; Fulton, Janet E

2015-06-16

Less than one-third of U.S. adults walk for transportation. Public health strategies to increase transportation walking would benefit from knowing what adults think is a reasonable distance to walk. Our purpose was to determine 1) what adults think is a reasonable distance and amount of time to walk and 2) whether there were differences in minutes spent transportation walking by what adults think is reasonable. Analyses used a cross-sectional nationwide adult sample (n = 3653) participating in the 2010 Summer ConsumerStyles mail survey. Most adults (> 90%) think transportation walking is reasonable. However, less than half (43%) think walking a mile or more or for 20 minutes or more is reasonable. What adults think is reasonable is similar across most demographic subgroups, except for older adults (≥ 65 years) who think shorter distances and times are reasonable. Trend analysis that adjust for demographic characteristics indicates adults who think longer distances and times are reasonable walk more. Walking for short distances is acceptable to most U.S. adults. Public health programs designed to encourage longer distance trips may wish to improve supports for transportation walking to make walking longer distances seem easier and more acceptable to most U.S. adults.

The cerebral cost of breathing: an FMRI case-study in congenital central hypoventilation syndrome.

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Mike Sharman

Full Text Available Certain motor activities--like walking or breathing--present the interesting property of proceeding either automatically or under voluntary control. In the case of breathing, brainstem structures located in the medulla are in charge of the automatic mode, whereas cortico-subcortical brain networks--including various frontal lobe areas--subtend the voluntary mode. We speculated that the involvement of cortical activity during voluntary breathing could impact both on the "resting state" pattern of cortical-subcortical connectivity, and on the recruitment of executive functions mediated by the frontal lobe. In order to test this prediction we explored a patient suffering from central congenital hypoventilation syndrome (CCHS, a very rare developmental condition secondary to brainstem dysfunction. Typically, CCHS patients demonstrate efficient cortically-controlled breathing while awake, but require mechanically-assisted ventilation during sleep to overcome the inability of brainstem structures to mediate automatic breathing. We used simultaneous EEG-fMRI recordings to compare patterns of brain activity between these two types of ventilation during wakefulness. As compared with spontaneous breathing (SB, mechanical ventilation (MV restored the default mode network (DMN associated with self-consciousness, mind-wandering, creativity and introspection in healthy subjects. SB on the other hand resulted in a specific increase of functional connectivity between brainstem and frontal lobe. Behaviorally, the patient was more efficient in cognitive tasks requiring executive control during MV than during SB, in agreement with her subjective reports in everyday life. Taken together our results provide insight into the cognitive and neural costs of spontaneous breathing in one CCHS patient, and suggest that MV during waking periods may free up frontal lobe resources, and make them available for cognitive recruitment. More generally, this study reveals how the

Rapid shallow breathing

Science.gov (United States)

Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... Shallow, rapid breathing has many possible medical causes, including: Asthma Blood clot in an artery in the ...

The Cerebral Cost of Breathing: An fMRI Case-Study in Congenital Central Hypoventilation Syndrome

Science.gov (United States)

Sharman, Mike; Gallea, Cécile; Lehongre, Katia; Galanaud, Damien; Nicolas, Nathalie; Similowski, Thomas; Cohen, Laurent; Straus, Christian; Naccache, Lionel

2014-01-01

Certain motor activities - like walking or breathing - present the interesting property of proceeding either automatically or under voluntary control. In the case of breathing, brainstem structures located in the medulla are in charge of the automatic mode, whereas cortico-subcortical brain networks - including various frontal lobe areas - subtend the voluntary mode. We speculated that the involvement of cortical activity during voluntary breathing could impact both on the “resting state” pattern of cortical-subcortical connectivity, and on the recruitment of executive functions mediated by the frontal lobe. In order to test this prediction we explored a patient suffering from central congenital hypoventilation syndrome (CCHS), a very rare developmental condition secondary to brainstem dysfunction. Typically, CCHS patients demonstrate efficient cortically-controlled breathing while awake, but require mechanically-assisted ventilation during sleep to overcome the inability of brainstem structures to mediate automatic breathing. We used simultaneous EEG-fMRI recordings to compare patterns of brain activity between these two types of ventilation during wakefulness. As compared with spontaneous breathing (SB), mechanical ventilation (MV) restored the default mode network (DMN) associated with self-consciousness, mind-wandering, creativity and introspection in healthy subjects. SB on the other hand resulted in a specific increase of functional connectivity between brainstem and frontal lobe. Behaviorally, the patient was more efficient in cognitive tasks requiring executive control during MV than during SB, in agreement with her subjective reports in everyday life. Taken together our results provide insight into the cognitive and neural costs of spontaneous breathing in one CCHS patient, and suggest that MV during waking periods may free up frontal lobe resources, and make them available for cognitive recruitment. More generally, this study reveals how the active

Imposed Work of Breathing and Breathing Comfort of Nonintubated Volunteers Breathing with Three Portable Ventilators and a Critical Care Ventilator

National Research Council Canada - National Science Library

Austin, Paul

2001-01-01

.... The purpose of this study was to assess the imposed inspiratory work of breathing and breathing comfort of nonintubated healthy volunteers breathing spontaneously through three portable ventilators...

Random walk on random walks

NARCIS (Netherlands)

Hilário, M.; Hollander, den W.Th.F.; Sidoravicius, V.; Soares dos Santos, R.; Teixeira, A.

2014-01-01

In this paper we study a random walk in a one-dimensional dynamic random environment consisting of a collection of independent particles performing simple symmetric random walks in a Poisson equilibrium with density ¿¿(0,8). At each step the random walk performs a nearest-neighbour jump, moving to

Sustained periodic terrestrial locomotion in air-breathing fishes.

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Pace, C M; Gibb, A C

2014-03-01

While emergent behaviours have long been reported for air-breathing osteichthyians, only recently have researchers undertaken quantitative analyses of terrestrial locomotion. This review summarizes studies of sustained periodic terrestrial movements by air-breathing fishes and quantifies the contributions of the paired appendages and the axial body to forward propulsion. Elongate fishes with axial-based locomotion, e.g. the ropefish Erpetoichthys calabaricus, generate an anterior-to-posterior wave of undulation that travels down the axial musculoskeletal system and pushes the body against the substratum at multiple points. In contrast, appendage-based locomotors, e.g. the barred mudskipper Periophthalmus argentilineatus, produce no axial bending during sustained locomotion, but instead use repeated protraction-retraction cycles of the pectoral fins to elevate the centre of mass and propel the entire body anteriorly. Fishes that use an axial-appendage-based mechanism, e.g. walking catfishes Clarias spp., produce side-to-side, whole-body bending in co-ordination with protraction-retraction cycles of the pectoral fins. Once the body is maximally bent to one side, the tail is pressed against the substratum and drawn back through the mid-sagittal plane, which elevates the centre of mass and rotates it about a fulcrum formed by the pectoral fin and the ground. Although appendage-based terrestrial locomotion appears to be rare in osteichthyians, many different species appear to have converged upon functionally similar axial-based and axial-appendage-based movements. Based on common forms observed across divergent taxa, it appears that dorsoventral compression of the body, elongation of the axial skeleton or the presence of robust pectoral fins can facilitate effective terrestrial movement by air-breathing fishes. © 2014 The Fisheries Society of the British Isles.

Relation between random walks and quantum walks

Science.gov (United States)

Boettcher, Stefan; Falkner, Stefan; Portugal, Renato

2015-05-01

Based on studies of four specific networks, we conjecture a general relation between the walk dimensions dw of discrete-time random walks and quantum walks with the (self-inverse) Grover coin. In each case, we find that dw of the quantum walk takes on exactly half the value found for the classical random walk on the same geometry. Since walks on homogeneous lattices satisfy this relation trivially, our results for heterogeneous networks suggest that such a relation holds irrespective of whether translational invariance is maintained or not. To develop our results, we extend the renormalization-group analysis (RG) of the stochastic master equation to one with a unitary propagator. As in the classical case, the solution ρ (x ,t ) in space and time of this quantum-walk equation exhibits a scaling collapse for a variable xdw/t in the weak limit, which defines dw and illuminates fundamental aspects of the walk dynamics, e.g., its mean-square displacement. We confirm the collapse for ρ (x ,t ) in each case with extensive numerical simulation. The exact values for dw themselves demonstrate that RG is a powerful complementary approach to study the asymptotics of quantum walks that weak-limit theorems have not been able to access, such as for systems lacking translational symmetries beyond simple trees.

Prospective randomized controlled intervention trial: Comprehensive Yogic Breathing Improves Cardiac autonomic functions and Quality of life in Diabetes

Directory of Open Access Journals (Sweden)

V P Jyotsna

2012-01-01

Full Text Available Aims and Objectives: To assess the effect of Comprehensive Yogic Breathing Program on glycemic control, quality of life, and cardiac autonomic functions in diabetes. Material and Methods: This is a prospective randomized controlled intervention trial. Cardiac autonomic functions were assessed in 120 diabetics. Patients were randomized into two groups, one group receiving standard therapy for diabetes (n = 56 and the other group receiving standard therapy for diabetes and comprehensive yogic breathing program (n = 64. Standard therapy included advice on diet, walk, and oral antidiabetic drugs. Comprehensive yogic breathing program was an interactive session in which Sudarshan kriya yoga, a rhythmic cyclical breathing, preceded by Pranayam was taught under guidance of a certified teacher. Change in fasting, post prandial blood sugars, glycated hemoglobin, and quality of life were assessed. Cardiac autonomic function tests were done before and six months after intervention. Results: There was significant improvement in psychological (P = 0.006 and social domains (P = 0.04 and total quality of life (P = 0.02 in the group practicing comprehensive yogic breathing program as compared to the group following standard therapy alone. In the group following breathing program, the improvement in sympathetic cardiac autonomic functions was statistically significant (P = 0.01, while the change in the standard group was not significant (P = 0.17. When both parasympathetic and sympathetic cardiac autonomic functions were considered, there was a trend toward improvement in patients following comprehensive yogic breathing program (P = 0.07. In the standard therapy group, no change in cardiac autonomic functions was noted (P = 0.76. The parameters of glycemic control were comparable in both groups. Conclusion: There was significant improvement in quality of life and cardiac autonomic functions in the diabetes patients practicing comprehensive yogic breathing

From Chicken Breath to the Killer Lakes of Cameroon: Uniting Seven Interesting Phenomena with a Single Chemical Underpinning.

Science.gov (United States)

DeLorenzo, Ron

2001-01-01

Recommends integrating different applications to serve the need for students to know the relevancy of the course of their future. Uses different and unrelated phenomena to teach equilibria. Introduces six phenomena; (1) Killer Lakes of Cameroon, (2) Chicken Breath, (3) The Permian Ocean, (4) Snow Line, (5) Hard-Water Boiler Scale, and (6)…

Understanding how dogs encourage and motivate walking: cross-sectional findings from RESIDE

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C. Westgarth

2016-09-01

Full Text Available Abstract Background Many people live with dogs but not all walk with them regularly. This study examines the demographic and behavioural factors that contribute towards owners reporting having a strong sense of encouragement and motivation to walk provided by their dogs, which we call ‘the Lassie effect’. Methods Data was collected from 629 dog owners participating in the RESIDE cross-sectional survey in Perth, Western Australia. Multivariable logistic regression analyses of factors associated with two separate outcome survey items ‘Dog encouragement to walk’ (how often dog encouraged me to go walking in last month and ‘Dog motivation to walk’ (Having a dog makes me walk more. Results Owning a larger dog; having an increased level of attachment to dog; knowing dog enjoys going for a walk; believing walking keeps dog healthy; and having high social support from family to go walking, were positively associated with both outcomes ‘dog encouragement to walk’ and ‘dog motivation to walk’. Conversely, reporting the presence of children at home; that the child is the main person who walks with the dog; and perceiving dog-specific barriers to walking with dog daily; were negatively associated with both outcomes. In addition, ‘Dog motivation to walk’ only was positively associated with a belief walking reduces barking, and negatively with owning a dog that is overweight or a dog that is too old/sick. Reporting that the spouse/partner is main person who walks with the dog was also negatively associated with ‘dog motivation to walk’, as was increased perceived access to public open spaces with dog-supportive features. Conclusions There are both dog and owner factors that are associated with an owner’s sense of encouragement, and motivation to walk the dog, which in turn has been found to be associated with dog waking behaviour. These factors may be targeted in future interventions to increase and maintain physical activity

‘Walking With’: A Rhythmanalysis of London’s East End

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Yi Chen

2013-12-01

Full Text Available In this paper, I will be looking at the practice of walking through the lens of rhythmanalysis. The method is brought to attention by Lefebvre’s last book Rhythmanalysis (2004 in which he suggests a way of interrelating space and time; a phenomenological inquiry hinged on the concrete experience of lived life. My interest in the nuance of walking was initially evoked by the structural film Fergus Walking which was made by the film maker William Raban in 1978. I will explore the potential of using structural films in sensitising us to the temporal-spatial relationship of things. The main body of the paper centres around two themes: Firstly I address the primacy of movement as a mode of engaging with the world. It is through ‘muscular consciousness’ (Bachelard 1964: 11 that walking becomes a form of experiential knowing, feeling, connecting and protesting. Secondly, I examine the practices of walking in relation to the radical transformations of the Docklands’ landscape since the beginning of the 1980s. I propose that the contesting interests of different groups can be explored by analysing the rhythmic interactions of their activities. The transition and recomposition of an economy from locally based industrial activities to globalised financial services were manifested in the syncopation of regeneration rhythms to the living rhythms of the Docklands. The fast changing urban landscapes were negotiated through alternative ways of navigating the streets, hence engendering a different set of rhythms.

In vivo proton MRS of normal pancreas metabolites during breath-holding and free-breathing

International Nuclear Information System (INIS)

Su, T.-H.; Jin, E.-H.; Shen, H.; Zhang, Y.; He, W.

2012-01-01

Aim: To characterize normal pancreas metabolites using in vivo proton magnetic resonance spectroscopy ( 1 H MRS) at 3 T under conditions of breath-holding and free-breathing. Materials and methods: The pancreases of 32 healthy volunteers were examined using 1 H MRS during breath-holding and free-breathing acquisitions in a single-voxel point-resolved selective spectroscopy sequence (PRESS) technique using a 3 T MRI system. Resonances were compared between paired spectra of the two breathing modes. Furthermore, correlations between lipid (Lip) content and age, body-mass index (BMI), as well as choline (Cho) peak visibility of the normal pancreas were analysed during breath-holding. Results: Twenty-nine pairs of spectra were successfully obtained showing three major resonances, Lip, Cho, cholesterol and the unsaturated parts of the olefinic region of fatty acids (Chol + Unsat). Breath-hold spectra were generally better, with higher signal-to-noise ratios (SNR; Z=–2.646, p = 0.008) and Cho peak visible status (Z=–2.449, p = 0.014). Correlations were significant between spectra acquired by the two breathing modes, especially for Lip height, Lip area, and the area of other peaks at 1.9–4.1 ppm. However, the Lip resonance was significantly different between the spectra of the two breathing modes (p 1 H MRS of the normal pancreas at 3 T is technically feasible and can characterize several metabolites. 1 H MRS during breath-holding acquisition is superior to that during free-breathing acquisition.

Fire-Walking

Science.gov (United States)

Willey, David

2010-01-01

This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

A Doppler Radar System for Sensing Physiological Parameters in Walking and Standing Positions

Directory of Open Access Journals (Sweden)

Malikeh Pour Ebrahim

2017-03-01

Full Text Available Doppler radar can be implemented for sensing physiological parameters wirelessly at a distance. Detecting respiration rate, an important human body parameter, is essential in a range of applications like emergency and military healthcare environments, and Doppler radar records actual chest motion. One challenge in using Doppler radar is being able to monitor several patients simultaneously and in different situations like standing, walking, or lying. This paper presents a complete transmitter-receiver Doppler radar system, which uses a 4 GHz continuous wave radar signal transmission and receiving system, to extract base-band data from a phase-shifted signal. This work reports experimental evaluations of the system for one and two subjects in various standing and walking positions. It provides a detailed signal analysis of various breathing rates of these two subjects simultaneously. These results will be useful in future medical monitoring applications.

Is breath acetone a biomarker of diabetes? A historical review on breath acetone measurements.

Science.gov (United States)

Wang, Zhennan; Wang, Chuji

2013-09-01

Since the ancient discovery of the 'sweet odor' in human breath gas, pursuits of the breath analysis-based disease diagnostics have never stopped. Actually, the 'smell' of the breath, as one of three key disease diagnostic techniques, has been used in Eastern-Medicine for more than three thousand years. With advancement of measuring technologies in sensitivity and selectivity, more specific breath gas species have been identified and established as a biomarker of a particular disease. Acetone is one of the breath gases and its concentration in exhaled breath can now be determined with high accuracy using various techniques and methods. With the worldwide prevalence of diabetes that is typically diagnosed through blood testing, human desire to achieve non-blood based diabetic diagnostics and monitoring has never been quenched. Questions, such as is breath acetone a biomarker of diabetes and how is the breath acetone related to the blood glucose (BG) level (the golden criterion currently used in clinic for diabetes diagnostic, monitoring, and management), remain to be answered. A majority of current research efforts in breath acetone measurements and its technology developments focus on addressing the first question. The effort to tackle the second question has begun recently. The earliest breath acetone measurement in clearly defined diabetic patients was reported more than 60 years ago. For more than a half-century, as reviewed in this paper, there have been more than 41 independent studies of breath acetone using various techniques and methods, and more than 3211 human subjects, including 1581 healthy people, 242 Type 1 diabetic patients, 384 Type 2 diabetic patients, 174 unspecified diabetic patients, and 830 non-diabetic patients or healthy subjects who are under various physiological conditions, have been used in the studies. The results of the breath acetone measurements collected in this review support that many conditions might cause changes to breath

Randomized random walk on a random walk

International Nuclear Information System (INIS)

Lee, P.A.

1983-06-01

This paper discusses generalizations of the model introduced by Kehr and Kunter of the random walk of a particle on a one-dimensional chain which in turn has been constructed by a random walk procedure. The superimposed random walk is randomised in time according to the occurrences of a stochastic point process. The probability of finding the particle in a particular position at a certain instant is obtained explicitly in the transform domain. It is found that the asymptotic behaviour for large time of the mean-square displacement of the particle depends critically on the assumed structure of the basic random walk, giving a diffusion-like term for an asymmetric walk or a square root law if the walk is symmetric. Many results are obtained in closed form for the Poisson process case, and these agree with those given previously by Kehr and Kunter. (author)

Nine Walks

DEFF Research Database (Denmark)

2013-01-01

Based on studies of, among others, the Situationists and their theories regarding walks as an artistic method and expression nine master students from “Studio Constructing an Archive”, Aarhus School of Architecture, Denmark performed nine walks as part of the exhibition. These walks relate...... to the students’ individual mappings of Behind the Green Door, its structure and content. They highlight a number of motifs found in the exhibition which are of particular interest to the students. The walks represented reflections on the walk as an artistic method and expression. Each walk is an individual...

What Causes Bad Breath?

Science.gov (United States)

... Videos for Educators Search English Español What Causes Bad Breath? KidsHealth / For Teens / What Causes Bad Breath? Print en español ¿Qué es lo que provoca el mal aliento? Bad breath, or halitosis , can be a major problem, ...

Breath biomarkers in toxicology.

Science.gov (United States)

Pleil, Joachim D

2016-11-01

Exhaled breath has joined blood and urine as a valuable resource for sampling and analyzing biomarkers in human media for assessing exposure, uptake metabolism, and elimination of toxic chemicals. This article focuses current use of exhaled gas, aerosols, and vapor in human breath, the methods for collection, and ultimately the use of the resulting data. Some advantages of breath are the noninvasive and self-administered nature of collection, the essentially inexhaustible supply, and that breath sampling does not produce potentially infectious waste such as needles, wipes, bandages, and glassware. In contrast to blood and urine, breath samples can be collected on demand in rapid succession and so allow toxicokinetic observations of uptake and elimination in any time frame. Furthermore, new technologies now allow capturing condensed breath vapor directly, or just the aerosol fraction alone, to gain access to inorganic species, lung pH, proteins and protein fragments, cellular DNA, and whole microorganisms from the pulmonary microbiome. Future applications are discussed, especially the use of isotopically labeled probes, non-targeted (discovery) analysis, cellular level toxicity testing, and ultimately assessing "crowd breath" of groups of people and the relation to dose of airborne and other environmental chemicals at the population level.

UNDERWATER STROKE KINEMATICS DURING BREATHING AND BREATH-HOLDING FRONT CRAWL SWIMMING

Directory of Open Access Journals (Sweden)

Nickos Vezos

2007-03-01

Full Text Available The aim of the present study was to determine the effects of breathing on the three - dimensional underwater stroke kinematics of front crawl swimming. Ten female competitive freestyle swimmers participated in the study. Each subject swam a number of front crawl trials of 25 m at a constant speed under breathing and breath-holding conditions. The underwater motion of each subject's right arm was filmed using two S-VHS cameras, operating at 60 Hz, which were positioned behind two underwater viewing windows. The spatial coordinates of selected points were calculated using the DLT procedure with 30 control points and after the digital filtering of the raw data with a cut-off frequency of 6 Hz, the hand's linear displacements and velocities were calculated. The results revealed that breathing caused significantly increases in the stroke duration (t9 = 2.764; p < 0.05, the backward hand displacement relative to the water (t9 = 2.471; p<0.05 and the lateral displacement of the hand in the X - axis during the downsweep (t9 = 2.638; p < 0.05. On the contrary, the peak backward hand velocity during the insweep (t9 = 2.368; p < 0.05 and the displacement of the hand during the push phase (t9 = -2.297; p < 0.05 were greatly reduced when breathing was involved. From the above, it was concluded that breathing action in front crawl swimming caused significant modifications in both the basic stroke parameters and the overall motor pattern were, possibly due to body roll during breathing

Walk Score(TM), Perceived Neighborhood Walkability, and walking in the US.

Science.gov (United States)

Tuckel, Peter; Milczarski, William

2015-03-01

To investigate both the Walk Score(TM) and a self-reported measure of neighborhood walkability ("Perceived Neighborhood Walkability") as estimators of transport and recreational walking among Americans. The study is based upon a survey of a nationally-representative sample of 1224 American adults. The survey gauged walking for both transport and recreation and included a self-reported measure of neighborhood walkability and each respondent's Walk Score(TM). Binary logistic and linear regression analyses were performed on the data. The Walk Score(TM) is associated with walking for transport, but not recreational walking nor total walking. Perceived Neighborhood Walkability is associated with transport, recreational and total walking. Perceived Neighborhood Walkability captures the experiential nature of walking more than the Walk Score(TM).

Breath in the technoscientific imaginary

OpenAIRE

Rose, Arthur

2016-01-01

Breath has a realist function in most artistic media. It serves to remind the reader, the viewer or the spectator of the exigencies of the body. In science fiction (SF) literature and films, breath is often a plot device for human encounters with otherness, either with alien peoples, who may not breathe oxygen, or environments, where there may not be oxygen to breathe. But while there is a technoscientific quality to breath in SF, especially in its attention to physiological systems, concentr...

Walking pattern classification and walking distance estimation algorithms using gait phase information.

Science.gov (United States)

Wang, Jeen-Shing; Lin, Che-Wei; Yang, Ya-Ting C; Ho, Yu-Jen

2012-10-01

This paper presents a walking pattern classification and a walking distance estimation algorithm using gait phase information. A gait phase information retrieval algorithm was developed to analyze the duration of the phases in a gait cycle (i.e., stance, push-off, swing, and heel-strike phases). Based on the gait phase information, a decision tree based on the relations between gait phases was constructed for classifying three different walking patterns (level walking, walking upstairs, and walking downstairs). Gait phase information was also used for developing a walking distance estimation algorithm. The walking distance estimation algorithm consists of the processes of step count and step length estimation. The proposed walking pattern classification and walking distance estimation algorithm have been validated by a series of experiments. The accuracy of the proposed walking pattern classification was 98.87%, 95.45%, and 95.00% for level walking, walking upstairs, and walking downstairs, respectively. The accuracy of the proposed walking distance estimation algorithm was 96.42% over a walking distance.

V3 spinal neurons establish a robust and balanced locomotor rhythm during walking.

Science.gov (United States)

Zhang, Ying; Narayan, Sujatha; Geiman, Eric; Lanuza, Guillermo M; Velasquez, Tomoko; Shanks, Bayle; Akay, Turgay; Dyck, Jason; Pearson, Keir; Gosgnach, Simon; Fan, Chen-Ming; Goulding, Martyn

2008-10-09

A robust and well-organized rhythm is a key feature of many neuronal networks, including those that regulate essential behaviors such as circadian rhythmogenesis, breathing, and locomotion. Here we show that excitatory V3-derived neurons are necessary for a robust and organized locomotor rhythm during walking. When V3-mediated neurotransmission is selectively blocked by the expression of the tetanus toxin light chain subunit (TeNT), the regularity and robustness of the locomotor rhythm is severely perturbed. A similar degeneration in the locomotor rhythm occurs when the excitability of V3-derived neurons is reduced acutely by ligand-induced activation of the allatostatin receptor. The V3-derived neurons additionally function to balance the locomotor output between both halves of the spinal cord, thereby ensuring a symmetrical pattern of locomotor activity during walking. We propose that the V3 neurons establish a regular and balanced motor rhythm by distributing excitatory drive between both halves of the spinal cord.

Unique mitochondrial localization of arginase 1 and 2 in hepatocytes of air-breathing walking catfish, Clarias batrachus and their differential expression patterns under hyper-ammonia stress.

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Banerjee, Bodhisattwa; Koner, Debaprasad; Lal, Priyanka; Saha, Nirmalendu

2017-07-30

Arginase (ARG) catalyzes the final step of ornithine-urea cycle (OUC) leading to a conversion of L-arginine to L-ornithine and urea. Several isoforms of ARG have been reported in vertebrates, out of which the two predominant isoforms are the cytosolic ARG1 and the mitochondrial ARG2. The air-breathing walking catfish (Clarias batrachus) is frequently being challenged by different environmental insults such as hyper-ammonia, dehydration and osmotic stresses in their natural habitats throughout the year. The present study investigated the active presence of ARG1 and ARG2 isoforms in hepatocytes along with unique localization of both the isoforms inside the mitochondria, and also their specific expression patterns under hyper-ammonia stress (5mM NH 4 Cl) in isolated hepatocytes of walking catfish. Initially, full length sequences of both arg1 and arg2 genes were obtained by RACE-PCR. Studies on molecular characterization demonstrated the presence of all the conserved amino acids required for stability and activity of binuclear metal center in both the isoforms. Phylogenetic analysis of the amino acid sequences of ARG isoforms showed a differentiation of the ARG1 and ARG2 into two distinct clusters with their respective isoforms from other species. Most interestingly, both the isoforms of ARG in hepatocytes were found to be localized inside the mitochondria as evidenced by the presence of mitochondrial target peptide (mTP) in N-terminal of the derived amino acid sequences, and exclusive localization of ARG activity in the mitochondrial fraction. This was additionally confirmed by Western blot analysis of ARGs in mitochondrial and cytosolic fractions, and by immunocytochemical analysis in isolated hepatocytes. Although the possible reasons associated with the presence of both the isoforms of ARGs inside the mitochondria is not clearly understood, perhaps this mitochondrial localization of ARG is functionally advantageous in this catfish for the synthesis of N

Bacterial Diversity in the Digestive Tracts of Four Indian Air-Breathing Fish Species Investigated by PCR Based Denaturing Gradient Gel Electrophoresis

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Suxu He

Full Text Available ABSTRACT An investigation was conducted to identify the allochthonous microbiota (entire intestine and the autochthonous microbiota in proximal intestine (PI and distal intestine (DI of four species of Indian air-breathing fish (climbing perch; Anabas testudineus, murrel; Channa punctatus, walking catfish; Clarias batrachus and stinging catfish; Heteropneustes fossilis by PCR based denaturing gradient gel electrophoresis (DGGE. High similarities of the allochthonous microbiota were observed between climbing perch and murrel, walking catfish and stinging catfish, indicating similar food behavior. The autochthonous microbiota of PI and DI from climbing perch and murrel revealed more similarity, than the result obtained from walking catfish and stinging catfish. The autochthonous microbiota of climbing perch and murrel were similar with regard to the allochthonous microbiota, but no such similarity was observed in case of walking catfish and stinging catfish. The fish genotype and intestinal bacteria are well matched and show co-evolutionary relationship. Three fish species has its unique bacteria; autochthonous Enterobacter cloacae, Edwardsiella tarda and Sphingobium sp. in DI of climbing perch, Pseudomonas sp.; allochthonous and autochthonous in PI of walking catfish and uncultured bacterium (EU697160.1, uncultured bacterium (JF018065.1 and uncultured bacterium (EU697160.1 for stinging catfish. In murrel, no unique bacteria were detected.

Who walks? Factors associated with walking behavior in disabled older women with and without self-reported walking difficulty.

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Simonsick, E M; Guralnik, J M; Fried, L P

1999-06-01

To determine how severity of walking difficulty and sociodemographic, psychosocial, and health-related factors influence walking behavior in disabled older women. Cross-sectional analyses of baseline data from the Women's Health and Aging Study (WHAS). An urban community encompassing 12 contiguous zip code areas in the eastern portion of Baltimore City and part of Baltimore County, Maryland. A total of 920 moderately to severely disabled community-resident women, aged 65 years and older, identified from an age-stratified random sample of Medicare beneficiaries. Walking behavior was defined as minutes walked for exercise and total blocks walked per week. Independent variables included self-reported walking difficulty, sociodemographic factors, psychological status (depression, mastery, anxiety, and cognition), and health-related factors (falls and fear of falling, fatigue, vision and balance problems, weight, smoking, and cane use). Walking at least 8 blocks per week was strongly negatively related to severity of walking difficulty. Independent of difficulty level, older age, black race, fatigue, obesity, and cane use were also negatively associated with walking; living alone and high mastery had a positive association with walking. Even among functionally limited women, sociocultural, psychological, and health-related factors were independently associated with walking behavior. Thus, programs aimed at improving walking ability need to address these factors in addition to walking difficulties to maximize participation and compliance.

Human Skeleton Model Based Dynamic Features for Walking Speed Invariant Gait Recognition

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Jure Kovač

2014-01-01

Full Text Available Humans are able to recognize small number of people they know well by the way they walk. This ability represents basic motivation for using human gait as the means for biometric identification. Such biometrics can be captured at public places from a distance without subject's collaboration, awareness, and even consent. Although current approaches give encouraging results, we are still far from effective use in real-life applications. In general, methods set various constraints to circumvent the influence of covariate factors like changes of walking speed, view, clothing, footwear, and object carrying, that have negative impact on recognition performance. In this paper we propose a skeleton model based gait recognition system focusing on modelling gait dynamics and eliminating the influence of subjects appearance on recognition. Furthermore, we tackle the problem of walking speed variation and propose space transformation and feature fusion that mitigates its influence on recognition performance. With the evaluation on OU-ISIR gait dataset, we demonstrate state of the art performance of proposed methods.

Breath in the technoscientific imaginary.

Science.gov (United States)

Rose, Arthur

2016-12-01

Breath has a realist function in most artistic media. It serves to remind the reader, the viewer or the spectator of the exigencies of the body. In science fiction (SF) literature and films, breath is often a plot device for human encounters with otherness, either with alien peoples, who may not breathe oxygen, or environments, where there may not be oxygen to breathe. But while there is a technoscientific quality to breath in SF, especially in its attention to physiological systems, concentrating on the technoscientific threatens to occlude other, more affective aspects raised by the literature. In order to supplement the tendency to read SF as a succession of technoscientific accounts of bodily experience, this paper recalls how SF texts draw attention to the affective, non-scientific qualities of breath, both as a metonym for life and as a metaphor for anticipation. Through an engagement with diverse examples from SF literature and films, this article considers the tension between technoscientific and affective responses to breath in order to demonstrate breath's co-determinacy in SF's blending of scientific and artistic discourses. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Chemical sensors for breath gas analysis: the latest developments at the Breath Analysis Summit 2013.

Science.gov (United States)

Tisch, Ulrike; Haick, Hossam

2014-06-01

Profiling the body chemistry by means of volatile organic compounds (VOCs) in the breath opens exciting new avenues in medical diagnostics. Gas sensors could provide ideal platforms for realizing portable, hand-held breath testing devices in the near future. This review summarizes the latest developments and applications in the field of chemical sensors for diagnostic breath testing that were presented at the Breath Analysis Summit 2013 in Wallerfangen, Germany. Considerable progress has been made towards clinically applicable breath testing devices, especially by utilizing chemo-sensitive nanomaterials. Examples of several specialized breath testing applications are presented that are either based on stand-alone nanomaterial-based sensors being highly sensitive and specific to individual breath compounds over others, or on combinations of several highly specific sensors, or on experimental nanomaterial-based sensors arrays. Other interesting approaches include the adaption of a commercially available MOx-based sensor array to indirect breath testing applications, using a sample pre-concentration method, and the development of compact integrated GC-sensor systems. The recent trend towards device integration has led to the development of fully integrated prototypes of point-of-care devices. We describe and compare the performance of several prototypes that are based on different sensing technologies and evaluate their potential as low-cost and readily available next-generation medical devices.

Shared and task-specific muscle synergies of Nordic walking and conventional walking.

Science.gov (United States)

Boccia, G; Zoppirolli, C; Bortolan, L; Schena, F; Pellegrini, B

2018-03-01

Nordic walking is a form of walking that includes a poling action, and therefore an additional subtask, with respect to conventional walking. The aim of this study was to assess whether Nordic walking required a task-specific muscle coordination with respect to conventional walking. We compared the electromyographic (EMG) activity of 15 upper- and lower-limb muscles of 9 Nordic walking instructors, while executing Nordic walking and conventional walking at 1.3 ms -1 on a treadmill. Non-negative matrix factorization method was applied to identify muscle synergies, representing the spatial and temporal organization of muscle coordination. The number of muscle synergies was not different between Nordic walking (5.2 ± 0.4) and conventional walking (5.0 ± 0.7, P = .423). Five muscle synergies accounted for 91.2 ± 1.1% and 92.9 ± 1.2% of total EMG variance in Nordic walking and conventional walking, respectively. Similarity and cross-reconstruction analyses showed that 4 muscle synergies, mainly involving lower-limb and trunk muscles, are shared between Nordic walking and conventional walking. One synergy acting during upper limb propulsion is specific to Nordic walking, modifying the spatial organization and the magnitude of activation of upper limb muscles compared to conventional walking. The inclusion of the poling action in Nordic walking does not increase the complexity of movement control and does not change the coordination of lower limb muscles. This makes Nordic walking a physical activity suitable also for people with low motor skill. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The use of active breathing control (ABC) to reduce margin for breathing motion

International Nuclear Information System (INIS)

Wong, John W.; Sharpe, Michael B.; Jaffray, David A.; Kini, Vijay R.; Robertson, John M.; Stromberg, Jannifer S.; Martinez, Alavro A.

1999-01-01

Purpose: For tumors in the thorax and abdomen, reducing the treatment margin for organ motion due to breathing reduces the volume of normal tissues that will be irradiated. A higher dose can be delivered to the target, provided that the risk of marginal misses is not increased. To ensure safe margin reduction, we investigated the feasibility of using active breathing control (ABC) to temporarily immobilize the patient's breathing. Treatment planning and delivery can then be performed at identical ABC conditions with minimal margin for breathing motion. Methods and Materials: An ABC apparatus is constructed consisting of 2 pairs of flow monitor and scissor valve, 1 each to control the inspiration and expiration paths to the patient. The patient breathes through a mouth-piece connected to the ABC apparatus. The respiratory signal is processed continuously, using a personal computer that displays the changing lung volume in real-time. After the patient's breathing pattern becomes stable, the operator activates ABC at a preselected phase in the breathing cycle. Both valves are then closed to immobilize breathing motion. Breathing motion of 12 patients were held with ABC to examine their acceptance of the procedure. The feasibility of applying ABC for treatment was tested in 5 patients by acquiring volumetric scans with a spiral computed tomography (CT) scanner during active breath-hold. Two patients had Hodgkin's disease, 2 had metastatic liver cancer, and 1 had lung cancer. Two intrafraction ABC scans were acquired at the same respiratory phase near the end of normal or deep inspiration. An additional ABC scan near the end of normal expiration was acquired for 2 patients. The ABC scans were also repeated 1 week later for a Hodgkin's patient. In 1 liver patient, ABC scans were acquired at 7 different phases of the breathing cycle to facilitate examination of the liver motion associated with ventilation. Contours of the lungs and livers were outlined when applicable

Effect of oxygenation on breath-by-breath response of the genioglossus muscle during occlusion.

Science.gov (United States)

Gauda, E B; Carroll, J L; McColley, S; Smith, P L

1991-10-01

We investigated the effect of different levels of O2 tension (hypoxia, normoxia, and hyperoxia) on the breath-by-breath onset and peak electromyographic (EMG) activity of the genioglossus (GG) muscle during a five-breath end-expiratory tracheal occlusion of 20- to 30-s duration. GG and diaphragmatic (DIA) EMG activity were measured with needle electrodes in eight anesthetized tracheotomized adult cats. In response to occlusion, the increase in the number of animals with GG EMG activity was different during hypoxia, normoxia, and hyperoxia (P = 0.003, Friedman). During hypoxia, eight of eight of the animals had GG EMG activity by the third occluded effort. In contrast, during normoxia, only four of eight and, during hyperoxia, only three of eight animals had GG EMG activity throughout the entire five-breath occlusion. Similarly, at release of the occlusion, more animals had persistent GG EMG activity on the postocclusion breaths during hypoxia than during normoxia or hyperoxia. Breath-by-breath augmentation of peak amplitude of the GG and DIA EMGs on each occluded effort was accentuated during hypoxia (P less than 0.01) and abolished during hyperoxia (P = 0.10). These results suggest that hypoxemia is a major determinant of the rapidity of onset, magnitude, and sustained activity of upper airway muscles during airway occlusion.

Determination of breath acetone in 149 type 2 diabetic patients using a ringdown breath-acetone analyzer.

Science.gov (United States)

Sun, Meixiu; Chen, Zhuying; Gong, Zhiyong; Zhao, Xiaomeng; Jiang, Chenyu; Yuan, Yuan; Wang, Zhennang; Li, Yingxin; Wang, Chuji

2015-02-01

Over 90% of diabetic patients have Type 2 diabetes. Although an elevated mean breath acetone concentration has been found to exist in Type 1 diabetes (T1D), information on breath acetone in Type 2 diabetes (T2D) has yet to be obtained. In this study, we first used gas chromatography-mass spectrometry (GC-MS) to validate a ringdown breath-acetone analyzer based on the cavity-ringdown-spectroscopy technique, through comparing breath acetone concentrations in the range 0.5-2.5 ppm measured using both methods. The linear fitting of R = 0.99 suggests that the acetone concentrations obtained using both methods are consistent with a largest standard deviation of ±0.4 ppm in the lowest concentration of the range. Next, 620 breath samples from 149 T2D patients and 42 healthy subjects were collected and tested using the breath analyzer. Four breath samples were taken from each subject under each of four different conditions: fasting, 2 h post-breakfast, 2 h post-lunch, and 2 h post-dinner. Simultaneous blood glucose levels were also measured using a standard diabetic-management blood-glucose meter. For the 149 T2D subjects, their exhaled breath acetone concentrations ranged from 0.1 to 19.8 ppm; four different ranges of breath acetone concentration, 0.1-19.8, 0.1-7.1, 0.1-6.3, and 0.1-9.5 ppm, were obtained for the subjects under the four different conditions, respectively. For the 42 healthy subjects, their breath acetone concentration ranged from 0.1 to 2.6 ppm; four different ranges of breath acetone concentration, 0.3-2.6, 0.1-2.6, 0.1-1.7, and 0.3-1.6 ppm, were obtained for the four different conditions. The mean breath acetone concentration of the 149 T2D subjects was determined to be 1.5 ± 1.5 ppm, which was 1.5 times that of 1.0 ± 0.6 ppm for the 42 healthy subjects. No correlation was found between the breath acetone concentration and the blood glucose level of the T2D subjects and the healthy volunteers. This study using a relatively large number of

Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

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Peeyush Sahay

2009-10-01

Full Text Available Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS, cavity ringdown spectroscopy (CRDS, integrated cavity output spectroscopy (ICOS, cavity enhanced absorption spectroscopy (CEAS, cavity leak-out spectroscopy (CALOS, photoacoustic spectroscopy (PAS, quartz-enhanced photoacoustic spectroscopy (QEPAS, and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS. Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis.

Body composition variation following diaphragmatic breathing ...

African Journals Online (AJOL)

Body composition variation following diaphragmatic breathing. ... effect of commonly prescribed diaphragmatic breathing training on the body composition ... a non-exercising control (NE) group (n = 22) or diaphragmatic breathing (DB) group.

Thoracic radiotherapy and breath control: current prospects

International Nuclear Information System (INIS)

Reboul, F.; Mineur, L.; Paoli, J.B.; Bodez, V.; Oozeer, R.; Garcia, R.

2002-01-01

Three-dimensional conformal radiotherapy (3D CRT) is adversely affected by setup error and organ motion. In thoracic 3D CRT, breathing accounts for most of intra-fraction movements, thus impairing treatment quality. Breath control clearly exhibits dosimetric improvement compared to free breathing, leading to various techniques for gated treatments. We review benefits of different breath control methods -i.e. breath-holding or beam gating, with spirometric, isometric or X-ray respiration sensor- and argument the choice of expiration versus inspiration, with consideration to dosimetric concerns. All steps of 3D-CRT can be improved with breath control. Contouring of organs at risk (OAR) and target are easier and more accurate on breath controlled CT-scans. Inter- and intra-fraction target immobilisation allows smaller margins with better coverage. Lung outcome predictors (NTCP, Mean Dose, LV20, LV30) are improved with breath-control. In addition, inspiration breath control facilitates beam arrangement since it widens the distance between OAR and target, and leaves less lung normal tissue within the high dose region. Last, lung density, as of CT scan, is more accurate, improving dosimetry. Our institutions choice is to use spirometry driven, patient controlled high-inspiration breath-hold; this technique gives excellent immobilization results, with high reproducibility, yet it is easy to implement and costs little extra treatment time. Breath control, whatever technique is employed, proves superior to free breathing treatment when using 3D-CRT. Breath control should then be used whenever possible, and is probably mandatory for IMRT. (authors)

Role of the dosed walking in the physical rehabilitation of children with bronchial asthma

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Gagara V.F.

2012-08-01

Full Text Available The results of research of influence on the respiratory system of children are presented with bronchial asthma of complex of methods of physical rehabilitation. In research 20 children took part 10-11 years. To put got the complex of rehabilitation measures, which included medical physical education. The complex of respiratory gymnastics was directed on the improvement of functioning of the respiratory system, improvement of function of the external breathing, increase of excursion of thorax and strengthening of respiratory muscles. Exercises of this complex were executed children in a slow rate with an accent on control of breathing during implementation of exercises. Additionally conducted engaged in the dosed walking and the special dynamic respiratory exercises were executed on the method of Tolkachev. The indexes of the functional state of the respiratory system of children are appraised. It is set that for patients the indexes of excursion of thorax were increased, vital capacity of lights, forced vital capacity of lights, volume of the forced exhalation for the first second, by volume speed of spades, index of Tifno.

News from the Breath Analysis Summit 2011.

Science.gov (United States)

Corradi, Massimo; Mutti, Antonio

2012-06-01

This special section highlights some of the important work presented at the Breath Analysis Summit 2011, which was held in Parma (Italy) from 11 to 14 September 2011. The meeting, which was jointly organized by the International Association for Breath Research and the University of Parma, was attended by more than 250 delegates from 33 countries, and offered 34 invited lectures and 64 unsolicited scientific contributions. The summit was organized to provide a forum to scientists, engineers and clinicians to present their latest findings and to meet industry executives and entrepreneurs to discuss key trends, future directions and technologies available for breath analysis. A major focus was on nitric oxide, exhaled breath condensate, electronic nose, mass spectrometry and newer sensor technologies. Medical applications ranged from asthma and other respiratory diseases to gastrointestinal disease, occupational diseases, critical care and cancer. Most people identify breath tests with breathalysers used by police to estimate ethanol concentration in blood. However, breath testing has far more sophisticated applications. Breath analysis is rapidly evolving as a new frontier in medical testing for disease states in the lung and beyond. Every individual has a breath fingerprint-or 'breathprint'-that can provide useful information about his or her state of health. This breathprint comprises the many thousands of molecules that are expelled with each breath we exhale. Breath research in the past few years has uncovered the scientific and molecular basis for such clinical observations. Relying on mass spectrometry, we have been able to identify many such unique substances in exhaled breath, including gases, such as nitric oxide (NO) and carbon monoxide (CO), and a wide array of volatile organic compounds. Exhaled breath also carries aerosolized droplets that can be collected as an exhaled breath condensate that contains endogenously produced non-volatile compounds. Breath

KidsWalk-to-School: A Guide To Promote Walking to School.

Science.gov (United States)

Center for Chronic Disease Prevention and Health Promotion (DHHS/CDC), Atlanta, GA.

This guide encourages people to create safe walking and biking routes to school, promoting four issues: physically active travel, safe and walkable routes to school, crime prevention, and health environments. The chapters include: "KidsWalk-to-School: A Guide to Promote Walking to School" (Is there a solution? Why is walking to school important?…

Walking training with cueing of cadence improves walking speed and stride length after stroke more than walking training alone: a systematic review.

Science.gov (United States)

Nascimento, Lucas R; de Oliveira, Camila Quel; Ada, Louise; Michaelsen, Stella M; Teixeira-Salmela, Luci F

2015-01-01

After stroke, is walking training with cueing of cadence superior to walking training alone in improving walking speed, stride length, cadence and symmetry? Systematic review with meta-analysis of randomised or controlled trials. Adults who have had a stroke. Walking training with cueing of cadence. Four walking outcomes were of interest: walking speed, stride length, cadence and symmetry. This review included seven trials involving 211 participants. Because one trial caused substantial statistical heterogeneity, meta-analyses were conducted with and without this trial. Walking training with cueing of cadence improved walking speed by 0.23 m/s (95% CI 0.18 to 0.27, I(2)=0%), stride length by 0.21 m (95% CI 0.14 to 0.28, I(2)=18%), cadence by 19 steps/minute (95% CI 14 to 23, I(2)=40%), and symmetry by 15% (95% CI 3 to 26, random effects) more than walking training alone. This review provides evidence that walking training with cueing of cadence improves walking speed and stride length more than walking training alone. It may also produce benefits in terms of cadence and symmetry of walking. The evidence appears strong enough to recommend the addition of 30 minutes of cueing of cadence to walking training, four times a week for 4 weeks, in order to improve walking in moderately disabled individuals with stroke. PROSPERO (CRD42013005873). Copyright © 2014 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

Complementarity and quantum walks

International Nuclear Information System (INIS)

Kendon, Viv; Sanders, Barry C.

2005-01-01

We show that quantum walks interpolate between a coherent 'wave walk' and a random walk depending on how strongly the walker's coin state is measured; i.e., the quantum walk exhibits the quintessentially quantum property of complementarity, which is manifested as a tradeoff between knowledge of which path the walker takes vs the sharpness of the interference pattern. A physical implementation of a quantum walk (the quantum quincunx) should thus have an identifiable walker and the capacity to demonstrate the interpolation between wave walk and random walk depending on the strength of measurement

Physiological aspect walking and Nordic walking as adequate kinetic activities.

OpenAIRE

BENEŠ, Václav

2010-01-01

This bachelor thesis on the topic of The Physiological Aspect of Walking and Nordic Walking as an adequate physical activity focuses on chosen physiological changes of an organism during a five-month training cycle. In the theoretical part I describe the physiological changes of organism during a regularly repeated strain, and also the technique of walking, Nordic walking and health benefits of these activities are defined here. The research part of the thesis describes the measurement method...

Walking Beliefs in Women With Fibromyalgia: Clinical Profile and Impact on Walking Behavior.

Science.gov (United States)

Peñacoba, Cecilia; Pastor, María-Ángeles; López-Roig, Sofía; Velasco, Lilian; Lledo, Ana

2017-10-01

Although exercise is essential for the treatment of fibromyalgia, adherence is low. Walking, as a form of physical exercise, has significant advantages. The aim of this article is to describe, in 920 women with fibromyalgia, the prevalence of certain walking beliefs and analyze their effects both on the walking behavior itself and on the associated symptoms when patients walk according to a clinically recommended way. The results highlight the high prevalence of beliefs related to pain and fatigue as walking-inhibitors. In the whole sample, beliefs are associated with an increased perception that comorbidity prevents walking, and with higher levels of pain and fatigue. In patients who walk regularly, beliefs are only associated with the perception that comorbidity prevents them from walking. It is necessary to promote walking according to the established way (including breaks to prevent fatigue) and to implement interventions on the most prevalent beliefs that inhibit walking.

SU-E-T-326: The Oxygen Saturation (SO2) and Breath-Holding Time Variation Applied Active Breathing Control (ABC)

Energy Technology Data Exchange (ETDEWEB)

Gong, G; Yin, Y [Shandong Cancer Hospital, Jinan, Shandong (China)

2014-06-01

Purpose: To study the oxygen saturation (SO2) and breath-holding time variation applied active breathing control (ABC) in radiotherapy of tumor. Methods: 24 volunteers were involved in our trials, and they all did breath-holding motion assisted by ELEKTA Active Breathing Coordinator 2.0 for 10 times respectively. And the patient monitor was used to observe the oxygen saturation (SO2) variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. Results: (1) The volunteers were divided into two groups according to the SO2 variation in breath-holding: A group, 14 cases whose SO2 reduction were more than 2% (initial value was 97% to 99%, while termination value was 91% to 96%); B group, 10 cases were less than 2% in breath-holding without inhaling oxygen. (2) The interfraction breath holding time varied from 8 to 20s for A group compared to the first breath-holding time, and for B group varied from 4 to 14s. (3) The breathing holding time of B group prolonged mean 8s, compared to A group. (4) The time for restoring to the initial value of SO2 was from 10s to 30s. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal. Conclusion: It is very obvious that the SO2 reduction in breath-holding associated with ABC for partial people. It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2.

Ultrasound for critical care physicians: take a deep breath

Directory of Open Access Journals (Sweden)

Ling D

2015-07-01

Full Text Available No abstract available. Article truncated at 150 words. A 40 year old man with a past medical history of intravenous drug abuse presented to the emergency department with difficulty walking and lower extremity weakness. He did admit to recent heroin use. He became somnolent in the ED and was given naloxone. However, he did not improve his level of consciousness sufficiently and was intubated for hypercarbia. The patient was transferred to the MICU and was evaluated for respiratory failure. He later that day passed a spontaneous breathing trial after he awoke and was extubated. However, he was soon thereafter was re-intubated for poor respiratory efforts and a weak cough. With an unexplained etiology for the respiratory failure, CT of the head, MRI of the brain and lab evaluation were pursued but were negative. At that point, a bedside ultrasound of the right hemi-diaphragm in the zone of apposition was obtained and is shown below: Figure 1. Ultrasound of ...

Effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force.

Science.gov (United States)

Park, Seung Kyu; Yang, Dae Jung; Kang, Yang Hun; Kim, Je Ho; Uhm, Yo Han; Lee, Yong Seon

2015-09-01

[Purpose] The purpose of this study was to investigate the effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force. [Subjects] The subjects of this study were 30 young adult males, who were divided into a Nordic walking group of 15 subjects and a walking group of 15 subjects. [Methods] To analyze the spatiotemporal parameters and ground reaction force during walking in the two groups, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for them between Nordic walking and walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. To determine the pole for Nordic walking, each subject's height was multiplied by 0.68. We then measured the spatiotemporal gait parameters and ground reaction force. [Results] Compared with the walking group, the Nordic walking group showed an increase in cadence, stride length, and step length, and a decrease in stride time, step time, and vertical ground reaction force. [Conclusion] The results of this study indicate that Nordic walking increases the stride and can be considered as helping patients with diseases affecting their gait. This demonstrates that Nordic walking is more effective in improving functional capabilities by promoting effective energy use and reducing the lower limb load, because the weight of the upper and lower limbs is dispersed during Nordic walking.

Walking drawings and walking ability in children with cerebral palsy.

Science.gov (United States)

Chong, Jimmy; Mackey, Anna H; Stott, N Susan; Broadbent, Elizabeth

2013-06-01

To investigate whether drawings of the self walking by children with cerebral palsy (CP) were associated with walking ability and illness perceptions. This was an exploratory study in 52 children with CP (M:F = 28:24), mean age 11.1 years (range 5-18), who were attending tertiary level outpatient clinics. Children were asked to draw a picture of themselves walking. Drawing size and content was used to investigate associations with clinical walk tests and children's own perceptions of their CP assessed using a CP version of the Brief Illness Perception Questionnaire. Larger drawings of the self were associated with less distance traveled, higher emotional responses to CP, and lower perceptions of pain or discomfort, independent of age. A larger self-to-overall drawing height ratio was related to walking less distance. Drawings of the self confined within buildings and the absence of other figures were also associated with reduced walking ability. Drawing size and content can reflect walking ability, as well as symptom perceptions and distress. Drawings may be useful for clinicians to use with children with cerebral palsy to aid discussion about their condition. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Walking performance: correlation between energy cost of walking and walking participation. new statistical approach concerning outcome measurement.

Directory of Open Access Journals (Sweden)

Marco Franceschini

Full Text Available Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW, in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS. One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance.

FMWC Radar for Breath Detection

DEFF Research Database (Denmark)

Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

We report on the experimental demonstration of an FMCW radar operating in the 25.7 - 26.6 GHz range with a repetition rate of 500 sweeps per second. The radar is able to track the breathing rate of an adult human from a distance of 1 meter. The experiments have utilized a 50 second recording window...... to accurately track the breathing rate. The radar utilizes a saw tooth modulation format and a low latency receiver. A breath tracking radar is useful both in medical scenarios, diagnosing disorders such as sleep apnea, and for home use where the user can monitor its health. Breathing is a central part of every...... radar chip which, through the use of a simple modulation scheme, is able to measure the breathing rate of an adult human from a distance. A high frequency output makes sure that the radar cannot penetrate solid obstacles which is a wanted feature in private homes where people therefore cannot measure...

Nordic walking versus walking without poles for rehabilitation with cardiovascular disease: Randomized controlled trial.

Science.gov (United States)

Girold, Sébastien; Rousseau, Jérome; Le Gal, Magalie; Coudeyre, Emmanuel; Le Henaff, Jacqueline

2017-07-01

With Nordic walking, or walking with poles, one can travel a greater distance and at a higher rate than with walking without poles, but whether the activity is beneficial for patients with cardiovascular disease is unknown. This randomized controlled trial was undertaken to determine whether Nordic walking was more effective than walking without poles on walk distance to support rehabilitation training for patients with acute coronary syndrome (ACS) and peripheral arterial occlusive disease (PAOD). Patients were recruited in a private specialized rehabilitation centre for cardiovascular diseases. The entire protocol, including patient recruitment, took place over 2 months, from September to October 2013. We divided patients into 2 groups: Nordic Walking Group (NWG, n=21) and Walking Group without poles (WG, n=21). All patients followed the same program over 4 weeks, except for the walk performed with or without poles. The main outcome was walk distance on the 6-min walk test. Secondary outcomes were maximum heart rate during exercise and walk distance and power output on a treadmill stress test. We included 42 patients (35 men; mean age 57.2±11 years and BMI 26.5±4.5kg/m 2 ). At the end of the training period, both groups showed improved walk distance on the 6-min walk test and treatment stress test as well as power on the treadmill stress test (PNordic walking training appeared more efficient than training without poles for increasing walk distance on the 6-min walk test for patients with ACS and PAOD. Copyright © 2017. Published by Elsevier Masson SAS.

Alzheimer random walk

Science.gov (United States)

Odagaki, Takashi; Kasuya, Keisuke

2017-09-01

Using the Monte Carlo simulation, we investigate a memory-impaired self-avoiding walk on a square lattice in which a random walker marks each of sites visited with a given probability p and makes a random walk avoiding the marked sites. Namely, p = 0 and p = 1 correspond to the simple random walk and the self-avoiding walk, respectively. When p> 0, there is a finite probability that the walker is trapped. We show that the trap time distribution can well be fitted by Stacy's Weibull distribution b(a/b){a+1}/{b}[Γ({a+1}/{b})]-1x^a\\exp(-a/bx^b)} where a and b are fitting parameters depending on p. We also find that the mean trap time diverges at p = 0 as p- α with α = 1.89. In order to produce sufficient number of long walks, we exploit the pivot algorithm and obtain the mean square displacement and its Flory exponent ν(p) as functions of p. We find that the exponent determined for 1000 step walks interpolates both limits ν(0) for the simple random walk and ν(1) for the self-avoiding walk as [ ν(p) - ν(0) ] / [ ν(1) - ν(0) ] = pβ with β = 0.388 when p ≪ 0.1 and β = 0.0822 when p ≫ 0.1. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

46 CFR 197.456 - Breathing supply hoses.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply....5 times its maximum working pressure; (2) Each breathing supply hose assembly, prior to being placed...

Visualizing Breath using Digital Holography

Science.gov (United States)

Hobson, P. R.; Reid, I. D.; Wilton, J. B.

2013-02-01

Artist Jayne Wilton and physicists Peter Hobson and Ivan Reid of Brunel University are collaborating at Brunel University on a project which aims to use a range of techniques to make visible the normally invisible dynamics of the breath and the verbal and non-verbal communication it facilitates. The breath is a source of a wide range of chemical, auditory and physical exchanges with the direct environment. Digital Holography is being investigated to enable a visually stimulating articulation of the physical trajectory of the breath as it leaves the mouth. Initial findings of this research are presented. Real time digital hologram replay allows the audience to move through holographs of breath-born particles.

Swimming in air-breathing fishes.

Science.gov (United States)

Lefevre, S; Domenici, P; McKenzie, D J

2014-03-01

Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise. © 2014 The Fisheries Society of the British Isles.

Breath-Hold Diving.

Science.gov (United States)

Fitz-Clarke, John R

2018-03-25

Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018. Copyright © 2018 American Physiological Society. All rights reserved.

System overview and walking dynamics of a passive dynamic walking robot with flat feet

Directory of Open Access Journals (Sweden)

Xinyu Liu

2015-12-01

Full Text Available The concept of “passive dynamic walking robot” refers to the robot that can walk down a shallow slope stably without any actuation and control which shows a limit cycle during walking. By adding actuation at some joints, the passive dynamic walking robot can walk stably on level ground and exhibit more versatile gaits than fully passive robot, namely, the “limit cycle walker.” In this article, we present the mechanical structures and control system design for a passive dynamic walking robot with series elastic actuators at hip joint and ankle joints. We built a walking model that consisted of an upper body, knee joints, and flat feet and derived its walking dynamics that involve double stance phases in a walking cycle based on virtual power principle. The instant just before impact was chosen as the start of one step to reduce the number of independent state variables. A numerical simulation was implemented by using MATLAB, in which the proposed passive dynamic walking model could walk stably down a shallow slope, which proves that the derived walking dynamics are correct. A physical passive robot prototype was built finally, and the experiment results show that by only simple control scheme the passive dynamic robot could walk stably on level ground.

Walking modality, but not task difficulty, influences the control of dual-task walking.

Science.gov (United States)

Wrightson, J G; Smeeton, N J

2017-10-01

During dual-task gait, changes in the stride-to-stride variability of stride time (STV) are suggested to represent the allocation of cognitive control to walking [1]. However, contrasting effects have been reported for overground and treadmill walking, which may be due to differences in the relative difficulty of the dual task. Here we compared the effect of overground and treadmill dual-task walking on STV in 18 healthy adults. Participants walked overground and on a treadmill for 120s during single-task (walking only) and dual-task (walking whilst performing serial subtractions in sevens) conditions. Dual-task effects on STV, cognitive task (serial subtraction) performance and perceived task difficulty were compared between walking modalities. STV was increased during overground dual-task walking, but was unchanged during treadmill dual-task walking. There were no differences in cognitive task performance or perceived task difficulty. These results show that gait is controlled differently during overground and treadmill dual-task walking. However, these differences are not solely due to differences in task difficulty, and may instead represent modality dependent control strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomechanical analysis of rollator walking

DEFF Research Database (Denmark)

Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

2006-01-01

The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

The role of arterial chemoreceptors in the breath-by-breath augmentation of inspiratory effort in rabbits during airway occlusion or elastic loading.

Science.gov (United States)

Callanan, D; Read, D J

1974-08-01

1. The breath-by-breath augmentation of inspiratory effort in the five breaths following airway occlusion or elastic loading was assessed in anaesthetized rabbits from changes of airway pressure, diaphragm e.m.g. and lung volume.2. When the airway was occluded in animals breathing air, arterial O(2) tension fell by 20 mmHg and CO(2) tension rose by 7 mmHg within the time of the first five loaded breaths.3. Inhalation of 100% O(2) or carotid denervation markedly reduced the breath-by-breath progression but had little or no effect on the responses at the first loaded breath.4. These results indicate that the breath-by-breath augmentation of inspiratory effort following addition of a load is mainly due to asphyxial stimulation of the carotid bodies, rather than to the gradual emergence of a powerful load-compensating reflex originating in the chest-wall, as postulated by some workers.5. The small residual progression seen in animals breathing 100% O(2) or following carotid denervation was not eliminated (a) by combining these procedures or (b) by addition of gas to the lungs to prevent the progressive lung deflation which occurred during airway occlusion.6. Bilateral vagotomy, when combined with carotid denervation, abolished the residual breath-by-breath progression of inspiratory effort.

Analysis of Exhaled Breath for Disease Detection

Science.gov (United States)

Amann, Anton; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Ligor, Tomasz; Jezierski, Tadeusz; Pleil, Joachim; Risby, Terence

2014-06-01

Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

Lévy walks

Science.gov (United States)

Zaburdaev, V.; Denisov, S.; Klafter, J.

2015-04-01

Random walk is a fundamental concept with applications ranging from quantum physics to econometrics. Remarkably, one specific model of random walks appears to be ubiquitous across many fields as a tool to analyze transport phenomena in which the dispersal process is faster than dictated by Brownian diffusion. The Lévy-walk model combines two key features, the ability to generate anomalously fast diffusion and a finite velocity of a random walker. Recent results in optics, Hamiltonian chaos, cold atom dynamics, biophysics, and behavioral science demonstrate that this particular type of random walk provides significant insight into complex transport phenomena. This review gives a self-consistent introduction to Lévy walks, surveys their existing applications, including latest advances, and outlines further perspectives.

Knowing We Know before We Know: ERP Correlates of Initial Feeling-of-Knowing

Science.gov (United States)

Paynter, Christopher A.; Reder, Lynne M.; Kieffaber, Paul D.

2009-01-01

Subjects performed a rapid feeling-of-knowing task developed by (Reder, L. M., & Ritter, F. (1992). "What determines initial feeling of knowing? Familiarity with question terms, not with the answer." "Journal of Experimental Psychology: Learning, Memory, and Cognition," 18, 435-451), while event-related potentials (ERPs) were recorded to identify…

Relationships between hippocampal activity and breathing patterns

DEFF Research Database (Denmark)

Harper, R M; Poe, G R; Rector, D M

1998-01-01

Single cell discharge, EEG activity, and optical changes accompanying alterations in breathing patterns, as well as the knowledge that respiratory musculature is heavily involved in movement and other behavioral acts, implicate hippocampal regions in some aspects of breathing control. The control...... is unlikely to reside in oscillatory breathing movements, because such patterns emerge in preparations retaining only the medulla (and perhaps only the spinal cord). However, momentary changes in breathing patterns induced by affect, startle, whole-body movement changes, or compensatory ventilatory changes...... of hippocampal contributions to breathing control should be viewed in the context that significant interactions exist between blood pressure changes and ventilation, and that modest breathing challenges, such as exposure to hypercapnia or to increased resistive loads, bring into action a vast array of brain...

Adults' Daily Walking for Travel and Leisure: Interaction Between Attitude Toward Walking and the Neighborhood Environment.

Science.gov (United States)

Yang, Yong; Diez-Roux, Ana V

2017-09-01

Studies on how the interaction of psychological and environmental characteristics influences walking are limited, and the results are inconsistent. Our aim is to examine how the attitude toward walking and neighborhood environments interacts to influence walking. Cross-sectional phone and mail survey. Participants randomly sampled from 6 study sites including Los Angeles, Chicago, Baltimore, Minneapolis, Manhattan, and Bronx Counties in New York City, and Forsyth and Davidson Counties in North Carolina. The final sample consisted of 2621 persons from 2011 to 2012. Total minutes of walking for travel or leisure, attitude toward walking, and perceptions of the neighborhood environments were self-reported. Street Smart (SS) Walk Score (a measure of walkability derived from a variety of geographic data) was obtained for each residential location. Linear regression models adjusting for age, gender, race/ethnicity, education, and income. Attitude toward walking was positively associated with walking for both purposes. Walking for travel was significantly associated with SS Walk Score, whereas walking for leisure was not. The SS Walk Score and selected perceived environment characteristics were associated with walking in people with a very positive attitude toward walking but were not associated with walking in people with a less positive attitude. Attitudes toward walking and neighborhood environments interact to affect walking behavior.

BREATHE to Understand©

Science.gov (United States)

Swisa, Maxine

2015-01-01

BREATHE is an acronym for Breathe, Reflect, Empathize, Accept, Thank, Hearten, Engage. The addition of Understand allows for a holistic approach to living a healthy and balanced life both inside and outside the classroom. This paper took form as a result of my personal, spiritual journey, as well as my teaching practice. I noticed that the…

Multimedia-assisted breathwalk-aware system.

Science.gov (United States)

Yu, Meng-Chieh; Wu, Huan; Lee, Ming-Sui; Hung, Yi-Ping

2012-12-01

Breathwalk is a science of combining specific patterns of footsteps synchronized with the breathing. In this study, we developed a multimedia-assisted Breathwalk-aware system which detects user's walking and breathing conditions and provides appropriate multimedia guidance on the smartphone. Through the mobile device, the system enhances user's awareness of walking and breathing behaviors. As an example application in slow technology, the system could help meditator beginners learn "walking meditation," a type of meditation which aims to be as slow as possible in taking pace, to synchronize footstep with breathing, and to land every footstep with toes first. In the pilot study, we developed a walking-aware system and evaluated whether multimedia-assisted mechanism is capable of enhancing beginner's walking awareness while walking meditation. Experimental results show that it could effectively assist beginners in slowing down the walking speed and decreasing incorrect footsteps. In the second experiment, we evaluated the Breathwalk-aware system to find a better feedback mechanism for learning the techniques of Breathwalk while walking meditation. The experimental results show that the visual-auditory mechanism is a better multimedia-assisted mechanism while walking meditation than visual mechanism and auditory mechanism.

Walking, sustainability and health: findings from a study of a Walking for Health group.

Science.gov (United States)

Grant, Gordon; Machaczek, Kasia; Pollard, Nick; Allmark, Peter

2017-05-01

Not only is it tacitly understood that walking is good for health and well-being but there is also now robust evidence to support this link. There is also growing evidence that regular short walks can be a protective factor for a range of long-term health conditions. Walking in the countryside can bring additional benefits, but access to the countryside brings complexities, especially for people with poorer material resources and from different ethnic communities. Reasons for people taking up walking as a physical activity are reasonably well understood, but factors linked to sustained walking, and therefore sustained benefit, are not. Based on an ethnographic study of a Walking for Health group in Lincolnshire, UK, this paper considers the motivations and rewards of group walks for older people. Nineteen members of the walking group, almost all with long-term conditions, took part in tape-recorded interviews about the personal benefits of walking. The paper provides insights into the links between walking as a sustainable activity and health, and why a combination of personal adaptive capacities, design elements of the walks and relational achievements of the walking group are important to this understanding. The paper concludes with some observations about the need to reframe conventional thinking about adherence to physical activity programmes. © 2017 John Wiley & Sons Ltd.

The Importance of the 6 Minute Walk test in the assessment of Romanian teenagers with cystic fibrosis

Directory of Open Access Journals (Sweden)

Ornela O. Cluci

2012-06-01

Full Text Available The measurement of lung function is the central part of the patients with cystic fibrosis assessment but we consider that exercise testing become an important tool in the continuous evaluation which is an indicative of prognosis and functional capacity and care of these patients. The 6 minute walk test is used to assess the individual’s response to exercise. The aim of the study is to design an exercise training program, based on 6 minute walk test and to evaluate the effects of this complex protocol including incentive therapy, individualized supervised training program: swimming, trampoline, walking, jogging, aerobic gymnastic, cycling 3 times per week and airway clearance techniques. Material and method: We conducted a 6-month study, on 20 patients from the Romanian National Cystic Fibrosis Center, aged between 12 and 18. The inclusion criteria were: FEV1 or FVC lower than 60% of predicted, SpO2 lower than 94% at rest. Results and discussions: The initial assessment showed limitations of exercise due to poor skeletal muscle mass, pulmonary status and respiratory muscle strength. After combining airway clearance techniques, incentive therapy and individualized physical training, we observed improvements regarding pulmonary function, ease of breathing and significant increased of fitness (6 minutes walking distance increased from 518.2±108.9 meters to 604.9±68 meters. A positive correlation was observed between skeletal muscle mass and distance achieved to 6 minute walk test, at the end of the study. Conclusion: The proposed rehabilitation protocol of young cystic fibrosis patients is efficient and creates pleasure and joy during physiotherapy which enhanced the patient’s adherence to the program.

Quantification of volatile organic compounds in exhaled human breath. Acetonitrile as biomarker for passive smoking. Model for isoprene in human breath

International Nuclear Information System (INIS)

Prazeller, P.

2000-03-01

The topic of this thesis is the quantification of volatile organic compounds in human breath under various circumstances. The composition of exhaled breath reflects metabolic processes in the human body. Breath analysis is a non invasive technique which makes it most interesting especially for medical or toxicological applications. Measurements were done with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS). This technique combines the advantage of small fragmentation of chemical ionization with highly time resolved mass spectrometry. A big part of this work is about investigations of exposition due to tobacco smoke. After smoking cigarettes the initial increase and time dependence of some compounds in the human breath are monitored . The calculated decrease resulting only from breathing out the compounds is presented and compared to the measured decline in the breath. This allows the distinction whether breathing is the dominant loss of a compound or a different metabolic process remover it more efficiently. Acetonitrile measured in human breath is presented as a biomarker for exposition to tobacco smoke. Especially its use for quantification of passive smoking, the exposition to environmental tobacco smoke (ETS) is shown. The reached accuracy and the fast way of measuring of acetonitrile in human breath using PTR-MS offer a good alternative to common used biomarkers. Numerous publications have described measurements of breath isoprene in humans, and there has been a hope that breath isoprene analyses could be a non-invasive diagnostic tool to assess serum cholesterol levels or cholesterol synthesis rate. However, significant analytical problems in breath isoprene analysis and variability in isoprene levels with age, exercise, diet, etc. have limited the usefulness of these measurements. Here, we have applied proton-transfer-reaction mass spectrometry (PTR-MS) to this problem, allowing on-line detection of breath isoprene. We show that breath isoprene

Quantum walk computation

International Nuclear Information System (INIS)

Kendon, Viv

2014-01-01

Quantum versions of random walks have diverse applications that are motivating experimental implementations as well as theoretical studies. Recent results showing quantum walks are “universal for quantum computation” relate to algorithms, to be run on quantum computers. We consider whether an experimental implementation of a quantum walk could provide useful computation before we have a universal quantum computer

Walking to health.

Science.gov (United States)

Morris, J N; Hardman, A E

1997-05-01

Walking is a rhythmic, dynamic, aerobic activity of large skeletal muscles that confers the multifarious benefits of this with minimal adverse effects. Walking, faster than customary, and regularly in sufficient quantity into the 'training zone' of over 70% of maximal heart rate, develops and sustains physical fitness: the cardiovascular capacity and endurance (stamina) for bodily work and movement in everyday life that also provides reserves for meeting exceptional demands. Muscles of the legs, limb girdle and lower trunk are strengthened and the flexibility of their cardinal joints preserved; posture and carriage may improve. Any amount of walking, and at any pace, expends energy. Hence the potential, long term, of walking for weight control. Dynamic aerobic exercise, as in walking, enhances a multitude of bodily processes that are inherent in skeletal muscle activity, including the metabolism of high density lipoproteins and insulin/glucose dynamics. Walking is also the most common weight-bearing activity, and there are indications at all ages of an increase in related bone strength. The pleasurable and therapeutic, psychological and social dimensions of walking, whilst evident, have been surprisingly little studied. Nor has an economic assessment of the benefits and costs of walking been attempted. Walking is beneficial through engendering improved fitness and/or greater physiological activity and energy turnover. Two main modes of such action are distinguished as: (i) acute, short term effects of the exercise; and (ii) chronic, cumulative adaptations depending on habitual activity over weeks and months. Walking is often included in studies of exercise in relation to disease but it has seldom been specifically tested. There is, nevertheless, growing evidence of gains in the prevention of heart attack and reduction of total death rates, in the treatment of hypertension, intermittent claudication and musculoskeletal disorders, and in rehabilitation after heart

Optoacoustic 13C-breath test analyzer

Science.gov (United States)

Harde, Hermann; Helmrich, Günther; Wolff, Marcus

2010-02-01

The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2 isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.

Increasing Walking in the Hartsfield-Jackson Atlanta International Airport: The Walk to Fly Study.

Science.gov (United States)

Fulton, Janet E; Frederick, Ginny M; Paul, Prabasaj; Omura, John D; Carlson, Susan A; Dorn, Joan M

2017-07-01

To test the effectiveness of a point-of-decision intervention to prompt walking, versus motorized transport, in a large metropolitan airport. We installed point-of-decision prompt signage at 4 locations in the airport transportation mall at Hartsfield-Jackson Atlanta International Airport (Atlanta, GA) at the connecting corridor between airport concourses. Six ceiling-mounted infrared sensors counted travelers entering and exiting the study location. We collected traveler counts from June 2013 to May 2016 when construction was present and absent (preintervention period: June 2013-September 2014; postintervention period: September 2014-May 2016). We used a model that incorporated weekly walking variation to estimate the intervention effect on walking. There was an 11.0% to 16.7% relative increase in walking in the absence of airport construction where 580 to 810 more travelers per day chose to walk. Through May 2016, travelers completed 390 000 additional walking trips. The Walk to Fly study demonstrated a significant and sustained increase in the number of airport travelers choosing to walk. Providing signage about options to walk in busy locations where reasonable walking options are available may improve population levels of physical activity and therefore improve public health.

Walk Score® and Transit Score® and Walking in the Multi-Ethnic Study of Atherosclerosis

Science.gov (United States)

Hirsch, Jana A.; Moore, Kari A.; Evenson, Kelly R.; Rodriguez, Daniel A; Diez Roux, Ana V.

2013-01-01

Background Walk Score® and Transit Score® are open-source measures of the neighborhood built environment to support walking (“walkability”) and access to transportation. Purpose To investigate associations of Street Smart Walk Score and Transit Score with self-reported transport and leisure walking using data from a large multi-city and diverse population-based sample of adults. Methods Data from a sample of 4552 residents of Baltimore MD; Chicago IL; Forsyth County NC; Los Angeles CA; New York NY; and St. Paul MN from the Multi-Ethnic Study of Atherosclerosis (2010–2012) were linked to Walk Score and Transit Score (collected in 2012). Logistic and linear regression models estimated ORs of not walking and mean differences in minutes walked, respectively, associated with continuous and categoric Walk Score and Transit Score. All analyses were conducted in 2012. Results After adjustment for site, key sociodemographic, and health variables, a higher Walk Score was associated with lower odds of not walking for transport and more minutes/week of transport walking. Compared to those in a “walker’s paradise,” lower categories of Walk Score were associated with a linear increase in odds of not transport walking and a decline in minutes of leisure walking. An increase in Transit Score was associated with lower odds of not transport walking or leisure walking, and additional minutes/week of leisure walking. Conclusions Walk Score and Transit Score appear to be useful as measures of walkability in analyses of neighborhood effects. PMID:23867022

Effects of walking and strength training on walking capacity in individuals with claudication: meta-analysis

Directory of Open Access Journals (Sweden)

Alessandra de Souza Miranda

2013-06-01

Full Text Available CONTEXT: Over the past few years, several clinical trials have been performed to analyze the effects of exercise training on walking ability in patients with intermittent claudication (IC. However, it remains unclear which type of physical exercise provides the maximum benefits in terms of walking ability. OBJECTIVE: To analyze, by means of a meta-analysis, the effects of walking and strength training on the walking capacity in patients with IC. METHODS: Papers analyzing the effects of walking and strength training programs in patients with IC were browsed on the Medline, Lilacs, and Cochrane databases. Randomized clinical trials scoring >4 on the Physiotherapy Evidence Database (PEDro scale and assessing claudication distance (CD and total walking distance (TWD were included in the review. RESULTS: Walking and strength training yielded increases in CD and TWD (P < 0.05. However, walking training yielded greater increases than strength training (P = 0.02. CONCLUSION: Walking and strength training improve walking capacity in patients with IC. However, greater improvements in TWD are obtained with walking training.

New breathing functions for the transverse breathing crack of the cracked rotor system: Approach for critical and subcritical harmonic analysis

Science.gov (United States)

Al-Shudeifat, Mohammad A.; Butcher, Eric A.

2011-01-01

The actual breathing mechanism of the transverse breathing crack in the cracked rotor system that appears due to the shaft weight is addressed here. As a result, the correct time-varying area moments of inertia for the cracked element cross-section during shaft rotation are also determined. Hence, two new breathing functions are identified to represent the actual breathing effect on the cracked element stiffness matrix. The new breathing functions are used in formulating the time-varying finite element stiffness matrix of the cracked element. The finite element equations of motion are then formulated for the cracked rotor system and solved via harmonic balance method for response, whirl orbits and the shift in the critical and subcritical speeds. The analytical results of this approach are compared with some previously published results obtained using approximate formulas for the breathing mechanism. The comparison shows that the previously used breathing function is a weak model for the breathing mechanism in the cracked rotor even for small crack depths. The new breathing functions give more accurate results for the dynamic behavior of the cracked rotor system for a wide range of the crack depths. The current approach is found to be efficient for crack detection since the critical and subcritical shaft speeds, the unique vibration signature in the neighborhood of the subcritical speeds and the sensitivity to the unbalance force direction all together can be utilized to detect the breathing crack before further damage occurs.

Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques

International Nuclear Information System (INIS)

Kartalis, Nikolaos; Loizou, Louiza; Edsborg, Nick; Albiin, Nils; Segersvaerd, Ralf

2012-01-01

To compare respiratory-triggered, free-breathing, and breath-hold DWI techniques regarding (1) image quality, and (2) signal intensity (SI) and ADC measurements in pancreatic ductal adenocarcinoma (PDAC). Fifteen patients with histopathologically proven PDAC underwent DWI prospectively at 1.5 T (b = 0, 50, 300, 600 and 1,000 s/mm 2 ) with the three techniques. Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images (lesion detection, anatomy, presence of artefacts) and ADC maps (lesion characterisation, overall image quality)] per technique and ranked them. The lesion SI, signal-to-noise ratio, mean ADC and coefficient of variation (CV) were compared. Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were 17.9, 16.5 and 17.1 respectively (respiratory-triggered was significantly higher than free-breathing but not breath-hold). The respiratory-triggered technique had a significantly higher ranking. Lesion SI on all b-values and signal-to-noise ratio on b300 and b600 were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1.201, 1.132 and 1.253 x 10 -3 mm 2 /s, and mean CVs were 8.9, 10.8 and 14.1 % respectively (respiratory-triggered and free-breathing techniques had a significantly lower mean CV than the breath-hold technique). In both analyses, respiratory-triggered DWI showed superiority and seems the optimal DWI technique for demonstrating PDAC. (orig.)

Walking economy during cued versus non-cued self-selected treadmill walking in persons with Parkinson's disease.

Science.gov (United States)

Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

2014-01-01

Gait impairments related to Parkinson's disease (PD) include variable step length and decreased walking velocity, which may result in poorer walking economy. Auditory cueing is a common method used to improve gait mechanics in PD that has been shown to worsen walking economy at set treadmill walking speeds. It is unknown if auditory cueing has the same effects on walking economy at self-selected treadmill walking speeds. To determine if auditory cueing will affect walking economy at self-selected treadmill walking speeds and at speeds slightly faster and slower than self-selected. Twenty-two participants with moderate PD performed three, 6-minute bouts of treadmill walking at three speeds (self-selected and ± 0.22 m·sec-1). One session used cueing and the other without cueing. Energy expenditure was measured and walking economy was calculated (energy expenditure/power). Poorer walking economy and higher energy expenditure occurred during cued walking at a self-selected and a slightly faster walking speed, but there was no apparent difference at the slightly slower speed. These results suggest that potential gait benefits of auditory cueing may come at an energy cost and poorer walking economy for persons with PD at least at some treadmill walking speeds.

You Spin my Head Right Round: Threshold of Limited Immersion for Rotation Gains in Redirected Walking.

Science.gov (United States)

Schmitz, Patric; Hildebrandt, Julian; Valdez, Andre Calero; Kobbelt, Leif; Ziefle, Martina

2018-04-01

In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

Relationships between breath ratios, spirituality and health ...

African Journals Online (AJOL)

The aim of this retrospective, quantitative study was to investigate relationships between breath ratios, spirituality perceptions and health perceptions, with special reference to breath ratios that best predict optimal health and spirituality. Significant negative correlations were found between breath ratios and spirituality ...

Biomechanical parameters in lower limbs during natural walking and Nordic walking at different speeds.

Science.gov (United States)

Dziuba, Alicja K; Żurek, Grzegorz; Garrard, Ian; Wierzbicka-Damska, Iwona

2015-01-01

Nordic Walking (NW) is a sport that has a number of benefits as a rehabilitation method. It is performed with specially designed poles and has been often recommended as a physical activity that helps reduce the load to limbs. However, some studies have suggested that these findings might be erroneous. The aim of this paper was to compare the kinematic, kinetic and dynamic parameters of lower limbs between Natural Walking (W) and Nordic Walking (NW) at both low and high walking speeds. The study used a registration system, BTS Smart software and Kistler platform. Eleven subjects walked along a 15-metre path at low (below 2 m⋅s-1) and high (over 2 m⋅s-1) walking speeds. The Davis model was employed for calculations of kinematic, kinetic and dynamic parameters of lower limbs. With constant speed, the support given by Nordic Walking poles does not make the stroke longer and there is no change in pelvic rotation either. The only change observed was much bigger pelvic anteversion in the sagittal plane during fast NW. There were no changes in forces, power and muscle torques in lower limbs. The study found no differences in kinematic, kinetic and dynamic parameters between Natural Walking (W) and Nordic Walking (NW). Higher speeds generate greater ground reaction forces and muscle torques in lower limbs. Gait parameters depend on walking speed rather than on walking style.

Cardiorespiratory interactions during resistive load breathing.

Science.gov (United States)

Calabrese, P; Perrault, H; Dinh, T P; Eberhard, A; Benchetrit, G

2000-12-01

The addition to the respiratory system of a resistive load results in breathing pattern changes and in negative intrathoracic pressure increases. The aim of this study was to use resistive load breathing as a stimulus to the cardiorespiratory interaction and to examine the extent of the changes in heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) in relation to the breathing pattern changes. HRV and RSA were studied in seven healthy subjects where four resistive loads were applied in a random order during the breath and 8-min recording made in each condition. The HRV spectral power components were computed from the R-R interval sequences, and the RSA amplitude and phase were computed from the sinusoid fitting the instantaneous heart rate within each breath. Adding resistive loads resulted in 1) increasing respiratory period, 2) unchanging heart rate, and 3) increasing HRV and changing RSA characteristics. HRV and RSA characteristics are linearly correlated to the respiratory period. These modifications appear to be linked to load-induced changes in the respiratory period in each individual, because HRV and RSA characteristics are similar at a respiratory period obtained either by loading or by imposed frequency breathing. The present results are discussed with regard to the importance of the breathing cycle duration in these cardiorespiratory interactions, suggesting that these interactions may depend on the time necessary for activation and dissipation of neurotransmitters involved in RSA.

Toe Walking in Children

Science.gov (United States)

... prone to damage and weaken over time. This diagnosis might be more likely if your child initially walked normally before starting to toe walk. Autism. Toe walking has been linked to autism spectrum ...

High-pitch coronary CT angiography in dual-source CT during free breathing vs. breath holding in patients with low heart rates

Energy Technology Data Exchange (ETDEWEB)

Bischoff, Bernhard, E-mail: bernhard.bischoff@med.uni-muenchen.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Meinel, Felix G. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Del Prete, Alessandra [Department of Radiology Magrassi-Lanzara, Second University of Naples, Naples (Italy); Reiser, Maximilian F.; Becker, Hans-Christoph [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany)

2013-12-01

Background: Coronary CT angiography (CCTA) is usually performed during breath holding to reduce motion artifacts caused by respiration. However, some patients are not able to follow the breathing commands adequately due to deafness, hearing impairment, agitation or pulmonary diseases. The aim of this study was to evaluate the potential of high-pitch CCTA in free breathing patients when compared to breath holding patients. Methods: In this study we evaluated 40 patients (20 free breathing and 20 breath holding patients) with a heart rate of 60 bpm or below referred for CCTA who were examined on a 2nd generation dual-source CT system. Image quality of each coronary artery segment was rated using a 4-point grading scale (1: non diagnostic–4: excellent). Results: Mean heart rate during image acquisition was 52 ±5 bpm in both groups. There was no significant difference in mean image quality, slightly favoring image acquisition during breath holding (mean image quality score 3.76 ± 0.32 in breath holding patients vs. 3.61 ± 0.45 in free breathing patients; p = 0.411). Due to a smaller amount of injected contrast medium, there was a trend for signal intensity to be slightly lower in free breathing patients, but this was not statistically significant (435 ± 123 HU vs. 473 ± 117 HU; p = 0.648). Conclusion: In patients with a low heart rate who are not able to hold their breath adequately, CCTA can also be acquired during free breathing without substantial loss of image quality when using a high pitch scan mode in 2nd generation dual-source CT.

Efficacy of a Respiratory Training System on the Regularity of Breathing

International Nuclear Information System (INIS)

Shin, Eun Hyuk; Park, Hee Chul; Han, Young Yih; Ju, Sang Gyu; Shin, Jung Suk; Ahn, Yong Chan

2008-01-01

In order to enhance the efficiency of respiratory gated 4-dimensional radiation therapy for more regular and stable respiratory period and amplitude, a respiration training system was designed, and its efficacy was evaluated. Materials and Methods: The experiment was designed to measure the difference in respiration regularity following the use of a training system. A total of 11 subjects (9 volunteers and 2 patients) were included in the experiments. Three different breathing signals, including free breathing (free-breathing), guided breathing that followed training software (guided-breathing), and free breathing after the guided-breathing (post guided-breathing), were consecutively recorded in each subject. The peak-to-peak (PTP) period of the breathing signal, standard deviation (SD), peak-amplitude and its SD, area of the one cycle of the breathing wave form, and its root mean square (RMS) were measured and computed. Results: The temporal regularity was significantly improved in guided-breathing since the SD of breathing period reduced (free-breathing 0.568 vs guided-breathing 0.344, p=0.0013). The SD of the breathing period representing the post guided-breathing was also reduced, but the difference was not statistically significant (free-breathing 0.568 vs. guided-breathing 0.512, p=ns). Also the SD of measured amplitude was reduced in guided-breathing (free-breathing 1.317 vs. guided-breathing 1.068, p=0.187), although not significant. This indicated that the tidal volume for each breath was kept more even in guided-breathing compared to free-breathing. There was no change in breathing pattern between free-breathing and guided-breathing. The average area of breathing wave form and its RMS in postguided-breathing, however, was reduced by 7% and 5.9%, respectively. Conclusion: The guided-breathing was more stable and regular than the other forms of breathing data. Therefore, the developed respiratory training system was effective in improving the temporal

Patients' experiences of breathing retraining for asthma: a qualitative process analysis of participants in the intervention arms of the BREATHE trial.

OpenAIRE

Arden-Close, E; Yardley, L; Kirby, S; Thomas, M; Bruton, A

2017-01-01

Poor symptom control and impaired quality of life are common in adults with asthma, and breathing retraining exercises may be an effective method of self-management. This study aimed to explore the experiences of participants in the intervention arms of the BREATHE trial, which investigated the effectiveness of breathing retraining as a mode of asthma management. Sixteen people with asthma (11 women, 8 per group) who had taken part in the intervention arms of the BREATHE trial (breathing retr...

Patients' experiences of breathing retraining for asthma: a qualitative process analysis of participants in the intervention arms of the BREATHE trial.

Science.gov (United States)

Arden-Close, Emily; Yardley, Lucy; Kirby, Sarah; Thomas, Mike; Bruton, Anne

2017-10-05

Poor symptom control and impaired quality of life are common in adults with asthma, and breathing retraining exercises may be an effective method of self-management. This study aimed to explore the experiences of participants in the intervention arms of the BREATHE trial, which investigated the effectiveness of breathing retraining as a mode of asthma management. Sixteen people with asthma (11 women, 8 per group) who had taken part in the intervention arms of the BREATHE trial (breathing retraining delivered by digital versatile disc (DVD) or face-to-face sessions with a respiratory physiotherapist) took part in semi-structured telephone interviews about their experiences. Interviews were analysed using thematic analysis. Breathing retraining was perceived positively as a method of asthma management. Motivations for taking part included being asked, to enhance progress in research, to feel better/reduce symptoms, and to reduce medication. Participants were positive about the physiotherapist, liked having the materials tailored, found meetings motivational, and liked the DVD and booklet. The impact of breathing retraining following regular practice included increased awareness of breathing and development of new habits. Benefits of breathing retraining included increased control over breathing, reduced need for medication, feeling more relaxed, and improved health and quality of life. Problems included finding time to practice the exercises, and difficulty mastering techniques. Breathing retraining was acceptable and valued by almost all participants, and many reported improved wellbeing. Face to face physiotherapy was well received. However, some participants in the DVD group mentioned being unable to master techniques. PATIENTS RECEPTIVE TO BREATHING RETRAINING: Patients with asthma taught how to change their unconscious breathing patterns generally like non-pharmacological interventions. Researchers in the UK, led by Mike Thomas from the University of Southampton

Towards The Design of a Smartphone-Based Biofeedback Breathing Training: Identifying Diaphragmatic Breathing Patterns from a Smartphone’s Microphone

OpenAIRE

Shih, Chen-Hsuan Iris; Kowatsch, Tobias; Tinschert, Peter; Barata, Filipe; Nißen, Marcia Katharina

2016-01-01

Asthma, diabetes, hypertension, or major depression are non-communicable diseases (NCDs) and impose a major burden on global health. Stress is linked to both the causes and consequences of NCDs and it has been shown that biofeedback-based breathing trainings (BBTs) are effective in coping with stress. Here, diaphragmatic breathing, i.e. deep abdominal breathing, belongs to the most distinguished breathing techniques. However, high costs and low scalability of state-of-the-art BBTs that requir...

Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques

Energy Technology Data Exchange (ETDEWEB)

Kartalis, Nikolaos; Loizou, Louiza; Edsborg, Nick; Albiin, Nils [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Segersvaerd, Ralf [Karolinska University Hospital, Division of Surgery, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden)

2012-10-15

To compare respiratory-triggered, free-breathing, and breath-hold DWI techniques regarding (1) image quality, and (2) signal intensity (SI) and ADC measurements in pancreatic ductal adenocarcinoma (PDAC). Fifteen patients with histopathologically proven PDAC underwent DWI prospectively at 1.5 T (b = 0, 50, 300, 600 and 1,000 s/mm{sup 2}) with the three techniques. Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images (lesion detection, anatomy, presence of artefacts) and ADC maps (lesion characterisation, overall image quality)] per technique and ranked them. The lesion SI, signal-to-noise ratio, mean ADC and coefficient of variation (CV) were compared. Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were 17.9, 16.5 and 17.1 respectively (respiratory-triggered was significantly higher than free-breathing but not breath-hold). The respiratory-triggered technique had a significantly higher ranking. Lesion SI on all b-values and signal-to-noise ratio on b300 and b600 were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1.201, 1.132 and 1.253 x 10{sup -3} mm{sup 2}/s, and mean CVs were 8.9, 10.8 and 14.1 % respectively (respiratory-triggered and free-breathing techniques had a significantly lower mean CV than the breath-hold technique). In both analyses, respiratory-triggered DWI showed superiority and seems the optimal DWI technique for demonstrating PDAC. (orig.)

Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

Science.gov (United States)

Geva, Ronny; Orr, Edna

2016-01-01

Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9) for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p developments, form an integrated adaptable composite, which possibly enables proactive internal resource reallocation, designed to support the emergence of new developmental milestones, such as walking.

Sports-related lung injury during breath-hold diving

Directory of Open Access Journals (Sweden)

Tanja Mijacika

2016-12-01

Full Text Available The number of people practising recreational breath-hold diving is constantly growing, thereby increasing the need for knowledge of the acute and chronic effects such a sport could have on the health of participants. Breath-hold diving is potentially dangerous, mainly because of associated extreme environmental factors such as increased hydrostatic pressure, hypoxia, hypercapnia, hypothermia and strenuous exercise. In this article we focus on the effects of breath-hold diving on pulmonary function. Respiratory symptoms have been reported in almost 25% of breath-hold divers after repetitive diving sessions. Acutely, repetitive breath-hold diving may result in increased transpulmonary capillary pressure, leading to noncardiogenic oedema and/or alveolar haemorrhage. Furthermore, during a breath-hold dive, the chest and lungs are compressed by the increasing pressure of water. Rapid changes in lung air volume during descent or ascent can result in a lung injury known as pulmonary barotrauma. Factors that may influence individual susceptibility to breath-hold diving-induced lung injury range from underlying pulmonary or cardiac dysfunction to genetic predisposition. According to the available data, breath-holding does not result in chronic lung injury. However, studies of large populations of breath-hold divers are necessary to firmly exclude long-term lung damage.

Allegheny County Walk Scores

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Walk Score measures the walkability of any address using a patented system developed by the Walk Score company. For each 2010 Census Tract centroid, Walk Score...

Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

Directory of Open Access Journals (Sweden)

Ronny Geva

Full Text Available Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9 for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p < .005, along with increases, counter to the general reduction trend, in skills that serve recruitment of external resources [socio-communication bids before speech (r = -.696, p < .01, and speech bids before walking; r = .729, p < .01]. Integration of these proactive changes using a computational approach yielded an even stronger link, underscoring internal resource reallocation as a facilitator of walking initiation (r = .901, p<0

"Religion" in Educational Spaces: Knowing, Knowing Well, and Knowing Differently

Science.gov (United States)

I'Anson, John; Jasper, Alison

2011-01-01

The focus of this article is how "religion", as a materially heterogeneous concept, becomes mobilized in different educational spaces, and the "kinds of knowing" to which this gives rise. Three "case studyish" illustrations are deployed in order to consider how religion and education produce kinds of knowing which…

21 CFR 868.5240 - Anesthesia breathing circuit.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anesthesia breathing circuit. 868.5240 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5240 Anesthesia breathing circuit. (a) Identification. An anesthesia breathing circuit is a device that is intended to administer medical gases to a...

ABA-Cloud: support for collaborative breath research.

Science.gov (United States)

Elsayed, Ibrahim; Ludescher, Thomas; King, Julian; Ager, Clemens; Trosin, Michael; Senocak, Uygar; Brezany, Peter; Feilhauer, Thomas; Amann, Anton

2013-06-01

This paper introduces the advanced breath analysis (ABA) platform, an innovative scientific research platform for the entire breath research domain. Within the ABA project, we are investigating novel data management concepts and semantic web technologies to document breath analysis studies for the long run as well as to enable their full automatic reproducibility. We propose several concept taxonomies (a hierarchical order of terms from a glossary of terms), which can be seen as a first step toward the definition of conceptualized terms commonly used by the international community of breath researchers. They build the basis for the development of an ontology (a concept from computer science used for communication between machines and/or humans and representation and reuse of knowledge) dedicated to breath research.

Optimal ventilatory patterns in periodic breathing.

Science.gov (United States)

Ghazanshahi, S D; Khoo, M C

1993-01-01

The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

Kineziologická charakteristika Nordic Walking

OpenAIRE

Pospíšilová, Petra

2009-01-01

Title: Functional a physiological characteristics of Nordic Walking Purposes: The aim of the thesis is to describe and summarize current knowledge about Nordic Walking Methods: Literature analysis Key words: Nordic Walking, free bipedal walk, health benefits, functional indicator changes

46 CFR 197.340 - Breathing gas supply.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Breathing gas supply. 197.340 Section 197.340 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A primary breathing gas supply for surface-supplied diving must be sufficient to support the following for the...

Bad Breath

Science.gov (United States)

... cabbage. And of course smoking causes its own bad smell. Some diseases and medicines can cause a specific breath odor. Having good dental habits, like brushing and flossing regularly, help fight bad ...

46 CFR 197.312 - Breathing supply hoses.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The maximum...

Quantum walks with entangled coins

International Nuclear Information System (INIS)

Venegas-Andraca, S E; Ball, J L; Burnett, K; Bose, S

2005-01-01

We present a mathematical formalism for the description of un- restricted quantum walks with entangled coins and one walker. The numerical behaviour of such walks is examined when using a Bell state as the initial coin state, with two different coin operators, two different shift operators, and one walker. We compare and contrast the performance of these quantum walks with that of a classical random walk consisting of one walker and two maximally correlated coins as well as quantum walks with coins sharing different degrees of entanglement. We illustrate that the behaviour of our walk with entangled coins can be very different in comparison to the usual quantum walk with a single coin. We also demonstrate that simply by changing the shift operator, we can generate widely different distributions. We also compare the behaviour of quantum walks with maximally entangled coins with that of quantum walks with non-entangled coins. Finally, we show that the use of different shift operators on two and three qubit coins leads to different position probability distributions in one- and two-dimensional graphs

Volatile sulphur compounds in morning breath of human volunteers.

NARCIS (Netherlands)

Snel, J.; Burgering, M.; Smit, B.; Noordman, W.; Tangerman, A.; Winkel, E.G.; Kleerebezem, M.

2011-01-01

OBJECTIVE: morning breath contains elevated concentrations of volatile sulphur components (VSCs). Therefore, morning breath is recognised as a surrogate target for interventions on breath quality. Nevertheless, factors influencing morning breath are poorly understood. Our aim was to evaluate

Volatile sulphur compounds in morning breath of human volunteers

NARCIS (Netherlands)

Snel, Johannes; Burgering, Maurits; Smit, Bart; Noordman, Wouter; Tangerman, Albert; Winkel, Edwin G.; Kleerebezem, Michiel

Objective: Morning breath contains elevated concentrations of volatile sulphur components (VSCs). Therefore, morning breath is recognised as a surrogate target for interventions on breath quality. Nevertheless, factors influencing morning breath are poorly understood. Our aim was to evaluate

Sudarshan kriya yoga: Breathing for health

Directory of Open Access Journals (Sweden)

Sameer A Zope

2013-01-01

Full Text Available Breathing techniques are regularly recommended for relaxation, stress management, control of psychophysiological states, and to improve organ function. Yogic breathing, defined as a manipulation of breath movement, has been shown to positively affect immune function, autonomic nervous system imbalances, and psychological or stress-related disorders. The aim of this study was to assess and provide a comprehensive review of the physiological mechanisms, the mind-body connection, and the benefits of Sudarshan Kriya Yoga (SKY in a wide range of clinical conditions. Various online databases searched were Medline, Psychinfo, EMBASE, and Google Scholar. All the results were carefully screened and articles on SKY were selected. The references from these articles were checked to find any other potentially relevant articles. SKY, a unique yogic breathing practice, involves several types of cyclical breathing patterns, ranging from slow and calming to rapid and stimulating. There is mounting evidence to suggest that SKY can be a beneficial, low-risk, low-cost adjunct to the treatment of stress, anxiety, post-traumatic stress disorder, depression, stress-related medical illnesses, substance abuse, and rehabilitation of criminal offenders.

Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

Directory of Open Access Journals (Sweden)

Sara L. Warber

2013-10-01

Full Text Available The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708 were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale, depression (Major Depressive Inventory, perceived stress (Perceived Stress Scale and emotional well-being (Positive and Negative Affect Schedule. Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through “green prescriptions” to improve psychological and emotional well-being, as well as physical activity.

Bad Breath

Science.gov (United States)

... garlic, onions, cheese, orange juice, and soda poor dental hygiene (say: HI-jeen), meaning not brushing and flossing regularly smoking and other tobacco use Poor oral hygiene leads to bad breath because when food particles ...

Breathing Difficulties

Science.gov (United States)

... symptoms. Symptoms associated with weak respiratory muscles: Air “hunger” (gasping, labored breathing) with an without activity Fatigue ... Start your own fundraising event & help create a world without ALS Start an Event Site Map | Press ...

Transcriptomic Analysis of Compromise Between Air-Breathing and Nutrient Uptake of Posterior Intestine in Loach (Misgurnus anguillicaudatus), an Air-Breathing Fish.

Science.gov (United States)

Huang, Songqian; Cao, Xiaojuan; Tian, Xianchang

2016-08-01

Dojo loach (Misgurnus anguillicaudatus) is an air-breathing fish species by using its posterior intestine to breathe on water surface. So far, the molecular mechanism about accessory air-breathing in fish is seldom addressed. Five cDNA libraries were constructed here for loach posterior intestines form T01 (the initial stage group), T02 (mid-stage of normal group), T03 (end stage of normal group), T04 (mid-stage of air-breathing inhibited group), and T05 (the end stage of air-breathing inhibited group) and subjected to perform RNA-seq to compare their transcriptomic profilings. A total of 92,962 unigenes were assembled, while 37,905 (40.77 %) unigenes were successfully annotated. 2298, 1091, and 3275 differentially expressed genes (fn1, ACE, EGFR, Pxdn, SDF, HIF, VEGF, SLC2A1, SLC5A8 etc.) were observed in T04/T02, T05/T03, and T05/T04, respectively. Expression levels of many genes associated with air-breathing and nutrient uptake varied significantly between normal and intestinal air-breathing inhibited group. Intraepithelial capillaries in posterior intestines of loaches from T05 were broken, while red blood cells were enriched at the surface of intestinal epithelial lining with 241 ± 39 cells per millimeter. There were periodic acid-schiff (PAS)-positive epithelial mucous cells in posterior intestines from both normal and air-breathing inhibited groups. Results obtained here suggested an overlap of air-breathing and nutrient uptake function of posterior intestine in loach. Intestinal air-breathing inhibition in loach would influence the posterior intestine's nutrient uptake ability and endothelial capillary structure stability. This study will contribute to our understanding on the molecular regulatory mechanisms of intestinal air-breathing in loach.

The assessment of the breath hold and the free breath methods about the blood flow evaluation by using phase contrast MRI

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Ho [Dept. of Radiology, Konkuk Medical center, Seoul (Korea, Republic of)

2016-06-15

Measurement of cardiac blood flow using the magnetic resonance imaging has been limited due to breathing and involuntary movements of the heart. The present study attempted to improve the accuracy of cardiac blood flow testing through phase contrast magnetic resonance imaging by presenting the adequate breathing method and imaging variables by comparing the measurement values of cardiac blood flow. Each was evaluated by comparing the breath hold retrospective 1NEX and non breath hold retrospective 1-3NEX in the ascending aorta and descending aorta. As a result, the average blood flow amount/ velocity of the breath hold retrosepctive 1NEX method in the ascending aorta were 96.17±19.12 ml/sec, 17.04±4.12 cm/sec respectively, which demonstrates a statistically significant difference(p<0.05) with the non-breath hold retrospective method 1NEX of 72.31±13.27 ml and 12.32±3.85. On the other hand, the average 2NEX blood flow and mean flow velocity is 101.90±24.09, 16.84±4.32, 3NEX 103.06±25.49, 16.88±4.19 did not show statistically significant differences(p>0.05).The average blood flow amount/ velocity of the breath hold retrospective 1NEX method in the descending aorta were 76.68±19.72 ml/s, and 22.23±4.8, which did not demonstrate a significant difference in comparison to non-breath hold retrospective method 1-3 NEX. Therefore, the non breath hold retrospective method does not significantly differ in terms of cardiac blood flow in comparison with the breath hold retrospective method in accordance with the increase of NEX, so pediatric patients or patients who are not able to breathe well must have the diagnostic value of their cardiac blood flow tests improved.

Beam walking can detect differences in walking balance proficiency across a range of sensorimotor abilities.

Science.gov (United States)

Sawers, Andrew; Ting, Lena H

2015-02-01

The ability to quantify differences in walking balance proficiency is critical to curbing the rising health and financial costs of falls. Current laboratory-based approaches typically focus on successful recovery of balance while clinical instruments often pose little difficulty for all but the most impaired patients. Rarely do they test motor behaviors of sufficient difficulty to evoke failures in balance control limiting their ability to quantify balance proficiency. Our objective was to test whether a simple beam-walking task could quantify differences in walking balance proficiency across a range of sensorimotor abilities. Ten experts, ten novices, and five individuals with transtibial limb loss performed six walking trials across three different width beams. Walking balance proficiency was quantified as the ratio of distance walked to total possible distance. Balance proficiency was not significantly different between cohorts on the wide-beam, but clear differences between cohorts on the mid and narrow-beams were identified. Experts walked a greater distance than novices on the mid-beam (average of 3.63±0.04m verus 2.70±0.21m out of 3.66m; p=0.009), and novices walked further than amputees (1.52±0.20m; p=0.03). Amputees were unable to walk on the narrow-beam, while experts walked further (3.07±0.14m) than novices (1.55±0.26m; p=0.0005). A simple beam-walking task and an easily collected measure of distance traveled detected differences in walking balance proficiency across sensorimotor abilities. This approach provides a means to safely study and evaluate successes and failures in walking balance in the clinic or lab. It may prove useful in identifying mechanisms underlying falls versus fall recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Walking on high heels changes muscle activity and the dynamics of human walking significantly

DEFF Research Database (Denmark)

Simonsen, Erik B; Svendsen, Morten Bo Søndergaard; Nørreslet, Andreas

2012-01-01

The aim of the study was to investigate the distribution of net joint moments in the lower extremities during walking on high-heeled shoes compared with barefooted walking at identical speed. Fourteen female subjects walked at 4 km/h across three force platforms while they were filmed by five...... digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...... phase was doubled when walking on high heels. The knee joint angle showed that high-heeled walking caused the subjects to flex the knee joint significantly more in the first half of the stance phase. In the frontal plane a significant increase was observed in the knee joint abductor moment and the hip...

How to breathe when you are short of breath

Science.gov (United States)

... you: Watch TV Use your computer Read a newspaper How to do Pursed lip Breathing The steps ... of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also ...

To Know or not to Know?

DEFF Research Database (Denmark)

Eriksen, Kathrine Krageskov

2015-01-01

raises ethical questions concerning the issue of knowing or not knowing about our genetic make-up. Thus, as techniques for genetic testing are increasingly employed, demands on health professionals are changing. Health professionals must be able to inform and guide patients, and therefore they need...

Minimal Walking Technicolor

DEFF Research Database (Denmark)

Foadi, Roshan; Frandsen, Mads Toudal; A. Ryttov, T.

2007-01-01

Different theoretical and phenomenological aspects of the Minimal and Nonminimal Walking Technicolor theories have recently been studied. The goal here is to make the models ready for collider phenomenology. We do this by constructing the low energy effective theory containing scalars......, pseudoscalars, vector mesons and other fields predicted by the minimal walking theory. We construct their self-interactions and interactions with standard model fields. Using the Weinberg sum rules, opportunely modified to take into account the walking behavior of the underlying gauge theory, we find...... interesting relations for the spin-one spectrum. We derive the electroweak parameters using the newly constructed effective theory and compare the results with the underlying gauge theory. Our analysis is sufficiently general such that the resulting model can be used to represent a generic walking technicolor...

Walking - Sensing - Participation

DEFF Research Database (Denmark)

Bødker, Mads; Meinhardt, Nina Dam; Browning, David

2014-01-01

Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider ...... set of experiential or ‘felt’ qualities of living with mobile technologies. Moving from reflections on the value of walking with people, the paper outlines some affordances of a smartphone application built to capture place experiences through walking.......Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider...

Optimal technique for deep breathing exercises after cardiac surgery.

Science.gov (United States)

Westerdahl, E

2015-06-01

Cardiac surgery patients often develop a restrictive pulmonary impairment and gas exchange abnormalities in the early postoperative period. Chest physiotherapy is routinely prescribed in order to reduce or prevent these complications. Besides early mobilization, positioning and shoulder girdle exercises, various breathing exercises have been implemented as a major component of postoperative care. A variety of deep breathing maneuvres are recommended to the spontaneously breathing patient to reduce atelectasis and to improve lung function in the early postoperative period. Different breathing exercises are recommended in different parts of the world, and there is no consensus about the most effective breathing technique after cardiac surgery. Arbitrary instructions are given, and recommendations on performance and duration vary between hospitals. Deep breathing exercises are a major part of this therapy, but scientific evidence for the efficacy has been lacking until recently, and there is a lack of trials describing how postoperative breathing exercises actually should be performed. The purpose of this review is to provide a brief overview of postoperative breathing exercises for patients undergoing cardiac surgery via sternotomy, and to discuss and suggest an optimal technique for the performance of deep breathing exercises.

Breath tests: principles, problems, and promise

International Nuclear Information System (INIS)

Lo, C.W.; Carter, E.A.; Walker, W.A.

1982-01-01

Breath tests rely on the measurement of gases produced in the intestine, absorbed, and expired in the breath. Carbohydrates, such as lactose and sucrose, can be administered in ysiologic doses; if malabsorbed, they will be metabolized to hydrogen by colonic bacteria. Since hydrogen is not produced by human metabolic reactions, a rise in breath hydrogen, as measured by gas chromatography, is evidence of carbohydrate malabsorption. Likewise, a rise in breath hydrogen marks the transit time of nonabsorbable carbohydrates such as lactulose through the small intestine into the colon. Simple end-expiratory interval collection into nonsiliconized vacutainer tubes has made these noninvasive tests quite convenient to perform, but various problems, including changes in stool pH intestinal motility, or metabolic rate, may influence results. Another group of breath tests uses substrates labeled with radioactive or stable isotopes of carbon. Labeled fat substrates such as trioctanoin, tripalmitin, and triolein do not produce the expected rise in labeled breath CO 2 if there is fat malabsorption. Bile acid malabsorption and small intestinal bacterial overgrowth can be measured with labeled cholylglycine or cholyltaurine. Labeled drugs such as aminopyrine, methacetin, and phenacetin can be used as an indication of drug metabolism and liver function. Radioactive substrates have been used to trace metabolic pathways and can be measured by scintillation counters. The availability of nonradioactive stable isotopes has made these ideal for use in children and pregnant women, but the cost of substrates and the mass spectrometers to measure them has so far limited their use to research centers. It is hoped that new techniques of processing and measurement will allow further realization of the exciting potential breath analysis has in a growing list of clinical applications

Effects of nasal positive expiratory pressure on dynamic hyperinflation and 6-minute walk test in patients with COPD.

Science.gov (United States)

Wibmer, Thomas; Rüdiger, Stefan; Heitner, Claudia; Kropf-Sanchen, Cornelia; Blanta, Ioanna; Stoiber, Kathrin M; Rottbauer, Wolfgang; Schumann, Christian

2014-05-01

Dynamic hyperinflation is an important target in the treatment of COPD. There is increasing evidence that positive expiratory pressure (PEP) could reduce dynamic hyperinflation during exercise. PEP application through a nasal mask and a flow resistance device might have the potential to be used during daily physical activities as an auxiliary strategy of ventilatory assistance. The aim of this study was to determine the effects of nasal PEP on lung volumes during physical exercise in patients with COPD. Twenty subjects (mean ± SD age 69.4 ± 6.4 years) with stable mild-to-severe COPD were randomized to undergo physical exercise with nasal PEP breathing, followed by physical exercise with habitual breathing, or vice versa. Physical exercise was induced by a standard 6-min walk test (6 MWT) protocol. PEP was applied by means of a silicone nasal mask loaded with a fixed-orifice flow resistor. Body plethysmography was performed immediately pre-exercise and post-exercise. Differences in mean pre- to post-exercise changes in total lung capacity (-0.63 ± 0.80 L, P = .002), functional residual capacity (-0.48 ± 0.86 L, P = .021), residual volume (-0.56 ± 0.75 L, P = .004), S(pO2) (-1.7 ± 3.4%, P = .041), and 6 MWT distance (-30.8 ± 30.0 m, P = .001) were statistically significant between the experimental and the control interventions. The use of flow-dependent expiratory pressure, applied with a nasal mask and a PEP device, might promote significant reduction of dynamic hyperinflation during walking exercise. Further studies are warranted addressing improvements in endurance performance under regular application of nasal PEP during physical activities.

The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease

Directory of Open Access Journals (Sweden)

Eileen G. Collins

2012-01-01

Full Text Available This randomized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program ( or walking-with-poles program ( of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( traditional walking and walking-with-poles. Using the near-infrared spectroscopy measures, StO2 was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from % prior to the treadmill test to % at peak exercise. The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

A Study of Effect of Walking Pole on the Walking Exercise

OpenAIRE

加藤, 麻樹; 下平, 佳江; 佐藤, 健

2010-01-01

So-called metabolic syndrome is one of the medical problems in our country, because many of people have difficulty at lack of exercises. Ministry of Health, Labor and Welfare suggest healthy life by exercise and moderate foods. Walking is one of the effective exercises to keep health in everyday life. Walking with poles, the exercise method of cross country skiing, is noticed as the effective exercise nowadays. Some studies show the effect of the pole walking exercise from view points of c...

Breathing and Singing: Objective Characterization of Breathing Patterns in Classical Singers.

Science.gov (United States)

Salomoni, Sauro; van den Hoorn, Wolbert; Hodges, Paul

2016-01-01

Singing involves distinct respiratory kinematics (i.e. movements of rib cage and abdomen) to quiet breathing because of different demands on the respiratory system. Professional classical singers often advocate for the advantages of an active control of the abdomen on singing performance. This is presumed to prevent shortening of the diaphragm, elevate the rib cage, and thus promote efficient generation of subglottal pressure during phonation. However, few studies have investigated these patterns quantitatively and inter-subject variability has hindered the identification of stereotypical patterns of respiratory kinematics. Here, seven professional classical singers and four untrained individuals were assessed during quiet breathing, and when singing both a standard song and a piece of choice. Several parameters were extracted from respiratory kinematics and airflow, and principal component analysis was used to identify typical patterns of respiratory kinematics. No group differences were observed during quiet breathing. During singing, both groups adapted to rhythmical constraints with decreased time of inspiration and increased peak airflow. In contrast to untrained individuals, classical singers used greater percentage of abdominal contribution to lung volume during singing and greater asynchrony between movements of rib cage and abdomen. Classical singers substantially altered the coordination of rib cage and abdomen during singing from that used for quiet breathing. Despite variations between participants, principal component analysis revealed consistent pre-phonatory inward movements of the abdominal wall during singing. This contrasted with untrained individuals, who demonstrated synchronous respiratory movements during all tasks. The inward abdominal movements observed in classical singers elevates intra-abdominal pressure and may increase the length and the pressure-generating capacity of rib cage expiratory muscles for potential improvements in voice

21 CFR 862.3080 - Breath nitric oxide test system.

Science.gov (United States)

2010-04-01

... Systems § 862.3080 Breath nitric oxide test system. (a) Identification. A breath nitric oxide test system... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath nitric oxide test system. 862.3080 Section... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to...

Off-line breath acetone analysis in critical illness.

Science.gov (United States)

Sturney, S C; Storer, M K; Shaw, G M; Shaw, D E; Epton, M J

2013-09-01

Analysis of breath acetone could be useful in the Intensive Care Unit (ICU) setting to monitor evidence of starvation and metabolic stress. The aims of this study were to examine the relationship between acetone concentrations in breath and blood in critical illness, to explore any changes in breath acetone concentration over time and correlate these with clinical features. Consecutive patients, ventilated on controlled modes in a mixed ICU, with stress hyperglycaemia requiring insulin therapy and/or new pulmonary infiltrates on chest radiograph were recruited. Once daily, triplicate end-tidal breath samples were collected and analysed off-line by selected ion flow tube mass spectrometry (SIFT-MS). Thirty-two patients were recruited (20 males), median age 61.5 years (range 26-85 years). The median breath acetone concentration of all samples was 853 ppb (range 162-11 375 ppb) collected over a median of 3 days (range 1-8). There was a trend towards a reduction in breath acetone concentration over time. Relationships were seen between breath acetone and arterial acetone (rs = 0.64, p acetone concentration over time corresponded to changes in arterial acetone concentration. Some patients remained ketotic despite insulin therapy and normal arterial glucose concentrations. This is the first study to look at breath acetone concentration in ICU patients for up to 8 days. Breath acetone concentration may be used as a surrogate for arterial acetone concentration, which may in future have a role in the modulation of insulin and feeding in critical illness.

Breath-to-breath variability of exhaled CO2 as a marker of lung dysmaturity in infancy.

Science.gov (United States)

Fouzas, Sotirios; Theodorakopoulos, Ilias; Delgado-Eckert, Edgar; Latzin, Philipp; Frey, Urs

2017-12-01

The concept of diffusional screening implies that breath-to-breath variations in CO 2 clearance, when related to the variability of breathing, may contain information on the quality and utilization of the available alveolar surface. We explored the validity of the above hypothesis in a cohort of young infants of comparable postmenstrual age but born at different stages of lung maturity, namely, in term-born infants ( n = 128), preterm-born infants without chronic lung disease of infancy (CLDI; n = 53), and preterm infants with moderate/severe CLDI ( n = 87). Exhaled CO 2 volume (V E,CO2 ) and concentration (F E,CO2 ) were determined by volumetric capnography, whereas their variance was assessed by linear and nonlinear variability metrics. The relationship between relative breath-to-breath change of V E,CO2 (ΔV E,CO2 ) and the corresponding change of tidal volume (ΔV T ) was also analyzed. Nonlinear F E,CO2 variability was lower in CLDI compared with term and non-CLDI preterm group ( P variability was attributed to the variability of V T ( r 2 = 0.749), whereas in term and healthy preterm infants this relationship was weaker ( r 2 = 0.507 and 0.630, respectively). The ΔV E,CO2 - ΔV T slope was less steep in the CLDI group (1.06 ± 0.07) compared with non-CLDI preterm (1.16 ± 0.07; P variability that can be quantified by nonlinear variability metrics and may reflect the degree of lung dysmaturity. In infants with moderate/severe chronic lung disease of infancy (CLDI), the variability of the exhaled CO 2 is mainly driven by the variability of breathing, whereas in term-born and healthy preterm infants this relationship is less strong. The slope of the relative CO 2 -to-volume change is less steep in CLDI infants, suggesting that dysmature lungs are less efficient in eliminating CO 2 under tidal breathing conditions.

Influence of Continuous Table Motion on Patient Breathing Patterns

International Nuclear Information System (INIS)

Wilbert, Juergen; Baier, Kurt; Richter, Anne; Herrmann, Christian; Ma Lei; Flentje, Michael; Guckenberger, Matthias

2010-01-01

Purpose: To investigate the influence of continuous table motion on patient breathing patterns for compensation of moving targets by a robotic treatment couch. Methods and Materials: Fifteen volunteers were placed on a robotic treatment couch, and the couch was moved on different breathing-correlated and -uncorrelated trajectories. External abdominal breathing motion of the patients was measured using an infrared camera system. The influence of table motion on breathing range and pattern was analyzed. Results: Continuous table motion was tolerated well by all test persons. Volunteers reacted differently to table motion. Four test persons showed no change of breathing range and pattern. Increased irregular breathing was observed in 4 patients; however, irregularity was not correlated with table motion. Only 4 test persons showed an increase in mean breathing amplitude of more than 2mm during motion of the couch. The mean cycle period decreased by more than 1 s for 2 test persons only. No abrupt changes in amplitude or cycle period could be observed. Conclusions: The observed small changes in breathing patterns support the application of motion compensation by a robotic treatment couch.

Optimization of sampling parameters for standardized exhaled breath sampling.

Science.gov (United States)

Doran, Sophie; Romano, Andrea; Hanna, George B

2017-09-05

The lack of standardization of breath sampling is a major contributing factor to the poor repeatability of results and hence represents a barrier to the adoption of breath tests in clinical practice. On-line and bag breath sampling have advantages but do not suit multicentre clinical studies whereas storage and robust transport are essential for the conduct of wide-scale studies. Several devices have been developed to control sampling parameters and to concentrate volatile organic compounds (VOCs) onto thermal desorption (TD) tubes and subsequently transport those tubes for laboratory analysis. We conducted three experiments to investigate (i) the fraction of breath sampled (whole vs. lower expiratory exhaled breath); (ii) breath sample volume (125, 250, 500 and 1000ml) and (iii) breath sample flow rate (400, 200, 100 and 50 ml/min). The target VOCs were acetone and potential volatile biomarkers for oesophago-gastric cancer belonging to the aldehyde, fatty acids and phenol chemical classes. We also examined the collection execution time and the impact of environmental contamination. The experiments showed that the use of exhaled breath-sampling devices requires the selection of optimum sampling parameters. The increase in sample volume has improved the levels of VOCs detected. However, the influence of the fraction of exhaled breath and the flow rate depends on the target VOCs measured. The concentration of potential volatile biomarkers for oesophago-gastric cancer was not significantly different between the whole and lower airway exhaled breath. While the recovery of phenols and acetone from TD tubes was lower when breath sampling was performed at a higher flow rate, other VOCs were not affected. A dedicated 'clean air supply' overcomes the contamination from ambient air, but the breath collection device itself can be a source of contaminants. In clinical studies using VOCs to diagnose gastro-oesophageal cancer, the optimum parameters are 500mls sample volume

Patient's breath controls comfort devices

Science.gov (United States)

Schrader, M.; Carpenter, B.; Nichols, C. D.

1972-01-01

Patient assist system for totally disabled persons was developed which permits a person, so paralyzed as to be unable to move, to activate by breathing, a call system to summon assistance, turn the page of a book, ajust his bed, or do any one of a number of other things. System consists of patient assist control and breath actuated switch.

Dog ownership, dog walking, and leisure-time walking among Taiwanese metropolitan and nonmetropolitan older adults.

Science.gov (United States)

Liao, Yung; Huang, Pin-Hsuan; Chen, Yi-Ling; Hsueh, Ming-Chun; Chang, Shao-Hsi

2018-04-04

This study examined the prevalence of dog ownership and dog walking and its association with leisure-time walking among metropolitan and nonmetropolitan older adults. A telephone-based cross-sectional survey targeting Taiwanese older adults was conducted in November 2016. Data related to dog ownership, time spent dog walking (categorized as non-dog owner, non-dog walkers, and dog walkers), and sociodemographic variables were obtained from 1074 older adults. Adjusted binary logistic regression was then performed. In this sample, 12% of Taiwanese older adults owned a dog and 31% of them walked their dogs for an average of 232.13 min over 5.9 days/week (standard deviation = 2.03). Older adults living in nonmetropolitan areas were more likely to own a dog (14.7% vs. 9.1%) but less likely to walk their dog (25.9% vs. 39.6%) than were those living in metropolitan areas. Compared with non-dog owners, only older adults living in nonmetropolitan areas who were dog walkers achieved 150 min of leisure-time walking (odds ratio: 3.03, 95% confidence interval: 1.05-8.77), after adjustment for potential confounders. Older Taiwanese adults living in nonmetropolitan areas who owned and walked their dogs were more likely to achieve health-enhancing levels of leisure-time walking. Tailored physical activity interventions for promoting dog walking should be developed for older adults who are dog owners living in nonmetropolitan areas and who do not engage in dog walking.

A fibre-optic oxygen sensor for monitoring human breathing

International Nuclear Information System (INIS)

Chen, Rongsheng; Formenti, Federico; Hahn, Clive E W; Farmery, Andrew D; Obeid, Andy

2013-01-01

The development and construction of a tapered-tip fibre-optic fluorescence based oxygen sensor is described. The sensor is suitable for fast and real-time monitoring of human breathing. The sensitivity and response time of the oxygen sensor were evaluated in vitro with a gas pressure chamber system, where oxygen partial pressure was rapidly changed between 5 and 15 kPa, and then in vivo in five healthy adult participants who synchronized their breathing to a metronome set at 10, 20, 30, 40, 50, and 60 breaths min –1 . A Datex Ultima medical gas analyser was used to monitor breathing rate as a comparator. The sensor's response time in vitro was less than 150 ms, which allows accurate continuous measurement of inspired and expired oxygen pressure. Measurements of breathing rate by means of our oxygen sensor and of the Datex Ultima were in strong agreement. The results demonstrate that the device can reliably resolve breathing rates up to 60 breaths min –1 , and that it is a suitable cost-effective alternative for monitoring breathing rates and end-tidal oxygen partial pressure in the clinical setting. The rapid response time of the sensor may allow its use for monitoring rapid breathing rates as occur in children and the newborn. (note)

Aerobic treadmill plus Bobath walking training improves walking in subacute stroke: a randomized controlled trial.

Science.gov (United States)

Eich, H-J; Mach, H; Werner, C; Hesse, S

2004-09-01

To evaluate the immediate and long-term effects of aerobic treadmill plus Bobath walking training in subacute stroke survivors compared with Bobath walking training alone. Randomized controlled trial. Rehabilitation unit. Fifty patients, first-time supratentorial stroke, stroke interval less than six weeks, Barthel Index (0-100) from 50 to 80, able to walk a minimum distance of 12 m with either intermittent help or stand-by while walking, cardiovascular stable, minimum 50 W in the bicycle ergometry, randomly allocated to two groups, A and B. Group A 30 min of treadmill training, harness secured and minimally supported according to patients' needs, and 30 min of physiotherapy, every workday for six weeks, speed and inclination of the treadmill were adjusted to achieve a heart rate of HR: (Hrmax-HRrest)*0.6+HRrest; in group B 60 min of daily physiotherapy for six weeks. Primary outcome variables were the absolute improvement of walking velocity (m/s) and capacity (m), secondary were gross motor function including walking ability (score out of 13) and walking quality (score out of 41), blindly assessed before and after the intervention, and at follow-up three months later. Patients tolerated the aerobic training well with no side-effects, significantly greater improvement of walking velocity and capacity both at study end (p =0.001 versus p =0.002) and at follow-up (p Bobath walking training in moderately affected stroke patients was better than Bobath walking training alone with respect to the improvement of walking velocity and capacity. The treatment approach is recommended in patients meeting the inclusion criteria. A multicentre trial should follow to strengthen the evidence.

Leukotriene-B4 concentrations in exhaled breath condensate and lung function after thirty minutes of breathing technically dried compressed air.

Science.gov (United States)

Neubauer, Birger; Struck, Niclas; Mutzbauer, Till S; Schotte, Ulrich; Langfeldt, Norbert; Tetzlaff, Kay

2002-01-01

In previous studies it had been shown that leukotriene-B4 [LTB4] concentrations in the exhaled breath mirror the inflammatory activity of the airways if the respiratory tract has been exposed to occupational hazards. In diving the respiratory tract is exposed to cold and dry air and the nasopharynx, as the site of breathing-gas warming and humidification, is bypassed. The aim of the present study was to obtain LTB4-concentrations in the exhaled breath and spirometric data of 17 healthy subjects before and after thirty minutes of technically dried air breathing at normobar ambient pressure. The exhaled breath was collected non-invasively, via a permanently cooled expiration tube. The condensate was measured by a standard enzyme immunoassay for LTB4. Lung function values (FVC, FEV1, MEF 25, MEF 50) were simultaneously obtained by spirometry. The measured pre- and post-exposure LTB4- concentrations as well as the lung function values were in the normal range. The present data gave no evidence for any inflammatory activity in the subjects' airways after thirty minutes breathing technically dried air.

Influence of the swing ankle angle on walking stability for a passive dynamic walking robot with flat feet

Directory of Open Access Journals (Sweden)

Xizhe Zang

2016-03-01

Full Text Available To achieve high walking stability for a passive dynamic walking robot is not easy. In this article, we aim to investigate whether the walking performance for a passive dynamic walking robot can be improved by just simply changing the swing ankle angle before impact. To validate this idea, a passive bipedal walking model with two straight legs, two flat feet, a hip joint, and two ankle joints was built in this study. The walking dynamics that contains double stance phase was derived. By numerical simulation of the walking in MATLAB, we found that the walking performance can be adjusted effectively by only simply changing the swing ankle angle before impact. A bigger swing ankle angle in a reasonable range will lead to a higher walking stability and a lower initial walking speed of the next step. A bigger swing ankle angle before impact leads to a bigger amount of energy lost during impact for the quasi-passive dynamic walking robot which will influence the walking stability of the next step.

The Walking Renaissance: A Longitudinal Analysis of Walking Travel in the Greater Los Angeles Area, USA

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Kenneth Joh

2015-07-01

Full Text Available Promoting walking travel is considered important for reducing automobile use and improving public health. Recent U.S. transportation policy has incentivized investments in alternative, more sustainable transportation modes such as walking, bicycling and transit in auto-oriented cities such as Los Angeles. Although many past studies have analyzed changes in walking travel across the U.S., there is little clarity on the drivers of change. We address this gap by conducting a longitudinal analysis of walking travel in the greater Los Angeles area from 2001 to 2009. We use travel diary and household data from regional and national surveys to analyze changes in walking trip shares and rates across our study area. Results show that walking has significantly increased across most of Los Angeles, and that increases in walking trips generally correspond with increases in population, employment, and transit service densities. Estimates from fixed-effects regression analysis generally suggest a positive association between population density and walking, and that higher increases in transit stop density are correlated with increased walking trips to and from transit stops. These findings illustrate how regional planning efforts to pursue a coordinated land use-transit planning strategy can help promote walking in auto-oriented or vehicle adopting cities.

Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker.

Science.gov (United States)

Lindemann, Ulrich; Schwenk, Michael; Schmitt, Syn; Weyrich, Michael; Schlicht, Wolfgang; Becker, Clemens

2017-08-01

Wheeled walkers are recommended to improve walking performance in older persons and to encourage and assist participation in daily life. Nevertheless, using a wheeled walker can cause serious problems in the natural environment. This study aimed to compare uphill and downhill walking with walking level in geriatric patients using a wheeled walker. Furthermore, we investigated the effect of using a wheeled walker with respect to dual tasking when walking level. A total of 20 geriatric patients (median age 84.5 years) walked 10 m at their habitual pace along a level surface, uphill and downhill, with and without a standard wheeled walker. Gait speed, stride length and cadence were assessed by wearable sensors and the walk ratio was calculated. When using a wheeled walker while walking level the walk ratio improved (0.58 m/[steps/min] versus 0.57 m/[steps/min], p = 0.023) but gait speed decreased (1.07 m/s versus 1.12 m/s, p = 0.020) when compared to not using a wheeled walker. With respect to the walk ratio, uphill and downhill walking with a wheeled walker decreased walking performance when compared to level walking (0.54 m/[steps/min] versus 0.58 m/[steps/min], p = 0.023 and 0.55 m/[steps/min] versus 0.58 m/[steps/min], p = 0.001, respectively). At the same time, gait speed decreased (0.079 m/s versus 1.07 m/s, p walker improved the quality of level walking but the performance of uphill and downhill walking was worse compared to walking level when using a wheeled walker.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

Science.gov (United States)

Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

2015-01-01

The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

[Objective evaluation of arterial intermittent claudication by the walking tolerance test. Comparative study of physiological walking and walking on a conveyor belt (author's transl)].

Science.gov (United States)

Bouchet, J Y; Franco, A; Morzol, B; Beani, J C

1980-01-01

Two methods are used to evaluate the walking distance: physiological walking along a standard path (0% - 6 mk/h) and walking on a tread mill (10% - 3 km/h). In both tests, four data are checked: -- initial trouble distance, -- cramp or walking-distance, -- localisation of pain, -- recovery time. These tests are dependable for the diagnosis of arterial claudication, reproducible and well tolerated. Their results have been compared: there is no correlation between the initial trouble distance and the cramp distance. However there is a correlation between the cramp distance by physiological walking and on treadmill. Recovery time, if long, is a criteria of gravity. Interests of both methods are discussed.

The effect of CO2 on ventilation and breath-holding during exercise and while breathing through an added resistance.

Science.gov (United States)

Clark, T J; Godfrey, S

1969-05-01

1. Ventilation was measured while subjects were made to rebreathe from a bag containing CO(2) and O(2) in order to expose them to a steadily rising CO(2) tension (P(CO2)). The object of the experiments was to determine the effect of a variety of stimuli upon the increase in ventilation and fall in breath-holding time which occurs in response to the rising P(CO2).2. Steady-state exercise at 200 kg.m/min resulted in a small fall in the slope of the ventilation-CO(2) response curve (S(V)) and a small, though not statistically significant, fall in the P(CO2) at which ventilation would be zero by extrapolation (B(V)). There was a marked fall in the slope of the breath-holding-CO(2) response curve (S(BH)) and an increase in the P(CO2) at which breath-holding time became zero by extrapolation (B(BH)).3. These results have been interpreted with the aid of a model of the control of breath-holding and it is suggested that there is no change in CO(2) sensitivity on exercise, either during rebreathing or breath-holding.4. An increase in the resistance to breathing caused a marked reduction in S(V) and B(V), but no change in the breath-holding-CO(2) response curve. These findings suggest that the flattening of the ventilation-CO(2) response curve is mechanical in origin and acute airway obstruction produces no change in CO(2) sensitivity.5. On the basis of these results, we suggest that more information about CO(2) sensitivity can be obtained by a combination of ventilation and breath-holding-CO(2) response curves.

21 CFR 862.3050 - Breath-alcohol test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath-alcohol test system. 862.3050 Section 862.3050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened...

Clinical Applications of CO2 and H2 Breath Test

Directory of Open Access Journals (Sweden)

ZHAO Si-qian;CHEN Bao-jun;LUO Zhi-fu

2016-08-01

Full Text Available Breath test is non-invasive, high sensitivity and high specificity. In this article, CO2 breath test, H2 breath test and their clinical applications were elaborated. The main applications of CO2 breath test include helicobacter pylori test, liver function detection, gastric emptying test, insulin resistance test, pancreatic exocrine secretion test, etc. H2 breath test can be applied in the diagnosis of lactose malabsorption and detecting small intestinal bacterial overgrowth. With further research, the breath test is expected to be applied in more diseases diagnosis.

Afternoon serum-melatonin in sleep disordered breathing.

Science.gov (United States)

Ulfberg, J; Micic, S; Strøm, J

1998-08-01

To study afternoon serum-melatonin values in patients with sleep disordered breathing. Melatonin has a strong circadian rhythm with high values during the night-time and low values in the afternoon. Sleep disordered breathing may change the circadian rhythm of melatonin which may have diagnostic implications. The Sleep Laboratory, The Department of Internal Medicine, Avesta Hospital, Sweden, and the Department of Anaesthesiology, Glostrup University Hospital, Copenhagen, Denmark. We examined 60 consecutive patients admitted for sleep disordered breathing and 10 healthy non snoring controls. The patients underwent a sleep apnoea screening test having a specificity of 100% for the obstructive sleep apnoea syndrome (OSAS) using a combination of static charge sensitive bed and oximetry. Obstructive sleep apnoea syndrome was found in 49 patients, eight patients had borderline sleep disordered breathing (BSDB) and three patients were excluded due to interfering disease. Patients and controls had an afternoon determination of serum-melatonin. The Epworth Sleepiness Scale was used to score day-time sleepiness. In comparison with normal controls patients suffering from OSAS had significantly higher serum-melatonin levels in the afternoon. However, as a diagnostic test for OSAS in patients with sleep disordered breathing serum-melatonin showed a low sensitivity but a high specificity. The results indicate that breathing disorders during sleep in general affect pineal function. Sleep disordered breathing seems to disturb pineal function. Determination of afternoon serum-melatonin alone or together with a scoring of daytime sleepiness does not identify OSAS-patients in a heterogeneous population of patients complaining of heavy snoring and excessive daytime sleepiness.

An Ultrasonic Contactless Sensor for Breathing Monitoring

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Philippe Arlotto

2014-08-01

Full Text Available The monitoring of human breathing activity during a long period has multiple fundamental applications in medicine. In breathing sleep disorders such as apnea, the diagnosis is based on events during which the person stops breathing for several periods during sleep. In polysomnography, the standard for sleep disordered breathing analysis, chest movement and airflow are used to monitor the respiratory activity. However, this method has serious drawbacks. Indeed, as the subject should sleep overnight in a laboratory and because of sensors being in direct contact with him, artifacts modifying sleep quality are often observed. This work investigates an analysis of the viability of an ultrasonic device to quantify the breathing activity, without contact and without any perception by the subject. Based on a low power ultrasonic active source and transducer, the device measures the frequency shift produced by the velocity difference between the exhaled air flow and the ambient environment, i.e., the Doppler effect. After acquisition and digitization, a specific signal processing is applied to separate the effects of breath from those due to subject movements from the Doppler signal. The distance between the source and the sensor, about 50 cm, and the use of ultrasound frequency well above audible frequencies, 40 kHz, allow monitoring the breathing activity without any perception by the subject, and therefore without any modification of the sleep quality which is very important for sleep disorders diagnostic applications. This work is patented (patent pending 2013-7-31 number FR.13/57569.

Random walks and diffusion on networks

Science.gov (United States)

Masuda, Naoki; Porter, Mason A.; Lambiotte, Renaud

2017-11-01

Random walks are ubiquitous in the sciences, and they are interesting from both theoretical and practical perspectives. They are one of the most fundamental types of stochastic processes; can be used to model numerous phenomena, including diffusion, interactions, and opinions among humans and animals; and can be used to extract information about important entities or dense groups of entities in a network. Random walks have been studied for many decades on both regular lattices and (especially in the last couple of decades) on networks with a variety of structures. In the present article, we survey the theory and applications of random walks on networks, restricting ourselves to simple cases of single and non-adaptive random walkers. We distinguish three main types of random walks: discrete-time random walks, node-centric continuous-time random walks, and edge-centric continuous-time random walks. We first briefly survey random walks on a line, and then we consider random walks on various types of networks. We extensively discuss applications of random walks, including ranking of nodes (e.g., PageRank), community detection, respondent-driven sampling, and opinion models such as voter models.

A comparison of at-home walking and 10-meter walking test parameters of individuals with post-stroke hemiparesis.

Science.gov (United States)

Nagano, Katsuhito; Hori, Hideaki; Muramatsu, Ken

2015-02-01

[Purpose] The purpose of this study was to clarify the difference in gait parameters of at-home walking and the 10-meter walking test results of individuals with hemiparesis. [Subjects] A total of 14 hemiparetic stroke recovery patients participated in this study. Inclusion criteria were: living at home, the ability to walk independently, and demonstrated low extremity on recovery stages III-V on the Brunnstrom Approach. The average age of the subjects was 66 years. [Methods] We used video surveillance and the inked footprint technique to record usual walking speed and maximum speed patterns both in subjects' homes and during the 10-meter walking test. From these methods, walking speed, stride length, and step rate were calculated. [Results] While both usual and maximum walking speeds of the 10-meter walking test correlated with stride length and step rate, at-home walking speeds only significantly correlated with stride length. [Conclusion] Walking patterns of the 10-meter walking test are quantifiably distinct from those demonstrated in patients' homes, and this difference is mainly characterized by stride length. In order to enhance in-home walking ability, exercises that improve length of stride rather than step rate should be recommended.

Advantage of using deep inspiration breath hold with active breathing control and image-guided radiation therapy for patients treated with lung cancers

International Nuclear Information System (INIS)

Muralidhar, K.R.; Madhusudhansresty; Sha, Rajib Lochan; Raut, Birendra Kumar; Poornima; Subash; Mallikarjun; Anil; Krishnam Raju, A.; Vidya; Sudarshan, G.; Mahadev, Shankar; Narayana Murthy, P.

2008-01-01

To evaluate the impact of moderate deep inspiration breath hold (mDIBH) using an active breathing control (ABC) apparatus on heart, spinal cord, liver and contra lateral lung doses and its volumes compared with free breathing (FB) with lung cancer irradiation

Non-Markovian decoherent quantum walks

International Nuclear Information System (INIS)

Xue Peng; Zhang Yong-Sheng

2013-01-01

Quantum walks act in obviously different ways from their classical counterparts, but decoherence will lessen and close this gap between them. To understand this process, it is necessary to investigate the evolution of quantum walks under different decoherence situations. In this article, we study a non-Markovian decoherent quantum walk on a line. In a short time regime, the behavior of the walk deviates from both ideal quantum walks and classical random walks. The position variance as a measure of the quantum walk collapses and revives for a short time, and tends to have a linear relation with time. That is, the walker's behavior shows a diffusive spread over a long time limit, which is caused by non-Markovian dephasing affecting the quantum correlations between the quantum walker and his coin. We also study both quantum discord and measurement-induced disturbance as measures of the quantum correlations, and observe both collapse and revival in the short time regime, and the tendency to be zero in the long time limit. Therefore, quantum walks with non-Markovian decoherence tend to have diffusive spreading behavior over long time limits, while in the short time regime they oscillate between ballistic and diffusive spreading behavior, and the quantum correlation collapses and revives due to the memory effect

Predictive value of 14CO2 breath tests for clinical use of 13CO2 breath tests

International Nuclear Information System (INIS)

Glaubitt, D.M.H.

1975-01-01

The knowledge of the efficiency of 14 CO 2 breath tests makes possible the comparison of the efficiency of analogous tests using the stable isotope 13 C. 14 CO 2 exhalation studies render overall information. After parenteral administration of a 14 C labeled substrate, 14 CO 2 breath tests permit insight into the metabolism of the 14 C substrate and the associated intermediary metabolism. If the 14 C substrate is given orally or by intraduodenal instillation, 14 CO 2 breath tests supply information not only about gastrointenstinal absorption and digestion but also about the intermediary metabolism yielding 14 CO 2 , after the administered substrate or its degradation products have been absorbed in the gastrointestinal tract. The fraction of 14 CO 2 arising from absorption, digestion and intermediary metabolism can be estimated only by additional methods. 14 CO 2 breath tests are unable to delineate single metabolic reactions involved in the formation of carbon dioxide. Under these considerations the clinical application of 14 CO 2 breath tests may provide diagnostically useful results, especially in internal medicine and surgery. The tests are suitable for intraindividual assessment of the course of a disease and of therapeutic effects. They may be important in the research of the metabolism of 14 C labeled substrates

Oral breathing and speech disorders in children

Directory of Open Access Journals (Sweden)

Silvia F. Hitos

2013-07-01

Conclusion: Mouth breathing can affect speech development, socialization, and school performance. Early detection of mouth breathing is essential to prevent and minimize its negative effects on the overall development of individuals.

Bad-breath: Perceptions and misconceptions of Nigerian adults.

Science.gov (United States)

Nwhator, S O; Isiekwe, G I; Soroye, M O; Agbaje, M O

2015-01-01

To provide baseline data about bad-breath perception and misconceptions among Nigerian adults. Multi-center cross-sectional study of individuals aged 18-64 years using examiner-administered questionnaires. Age comparisons were based on the model of emerging adults versus full adults. Data were recoded for statistical analyses and univariate and secondary log-linear statistics applied. Participants had lopsided perceptions about bad-breath. While 730 (90.8%) identified the dentist as the expert on halitosis and 719 (89.4%) knew that bad-breath is not contagious, only 4.4% and 2.5% associated bad-breath with tooth decay and gum disease respectively. There were no significant sex differences but the older adults showed better knowledge in a few instances. Most respondents (747, 92.9%) would tell a spouse about their bad-breath and 683 (85%) would tell a friend. Participants had lop-sided knowledge and perceptions about bad-breath. Most Nigerian adults are their "brothers' keepers" who would tell a spouse or friend about their halitosis so they could seek treatment.

The effect of mouth breathing on chewing efficiency.

Science.gov (United States)

Nagaiwa, Miho; Gunjigake, Kaori; Yamaguchi, Kazunori

2016-03-01

To examine the effect of mouth breathing on chewing efficiency by evaluating masticatory variables. Ten adult nasal breathers with normal occlusion and no temporomandibular dysfunction were selected. Subjects were instructed to bite the chewing gum on the habitual side. While breathing through the mouth and nose, the glucide elution from the chewing gum, number of chewing strokes, duration of chewing, and electromyography (EMG) activity of the masseter muscle were evaluated as variables of masticatory efficiency. The durations required for the chewing of 30, 60, 90, 120, 180, and 250 strokes were significantly (P chewing stroke between nose and mouth breathings. The glucide elution rates for 1- and 3-minute chewing were significantly (P chewing between nose and mouth breathings. While chewing for 1, 3, and 5 minutes, the chewing stroke and EMG activity of the masseter muscle were significantly (P chewing to obtain higher masticatory efficiency when breathing through the mouth. Therefore, mouth breathing will decrease the masticatory efficiency if the duration of chewing is restricted in everyday life.

Neuromorphic walking gait control.

Science.gov (United States)

Still, Susanne; Hepp, Klaus; Douglas, Rodney J

2006-03-01

We present a neuromorphic pattern generator for controlling the walking gaits of four-legged robots which is inspired by central pattern generators found in the nervous system and which is implemented as a very large scale integrated (VLSI) chip. The chip contains oscillator circuits that mimic the output of motor neurons in a strongly simplified way. We show that four coupled oscillators can produce rhythmic patterns with phase relationships that are appropriate to generate all four-legged animal walking gaits. These phase relationships together with frequency and duty cycle of the oscillators determine the walking behavior of a robot driven by the chip, and they depend on a small set of stationary bias voltages. We give analytic expressions for these dependencies. This chip reduces the complex, dynamic inter-leg control problem associated with walking gait generation to the problem of setting a few stationary parameters. It provides a compact and low power solution for walking gait control in robots.

Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.

Science.gov (United States)

Llewellyn, M; Yang, J F; Prochazka, A

1990-01-01

Hoffman (H) reflexes were elicited from the soleus (SOL) muscle while subjects walked on a treadmill and on a narrow beam (3.5 cm wide, raised 34 cm from the floor). The speed of walking on the treadmill was selected for each subject to match the background activation level of their SOL muscle during beam walking. The normal reciprocal activation pattern of the tibialis anterior and SOL muscles in treadmill walking was replaced by a pattern dominated by co-contraction on the beam. In addition, the step cycle duration was more variable and the time spent in the swing phase was reduced on the beam. The H-reflexes were highly modulated in both tasks, the amplitude being high in the stance phase and low in the swing phase. The H-reflex amplitude was on average 40% lower during beam walking than treadmill walking. The relationship between the H-reflex amplitude and the SOL EMG level was quantified by a regression line relating the two variables. The slope of this line was on average 41% lower in beam walking than treadmill walking. The lower H-reflex gain observed in this study and the high level of fusimotor drive observed in cats performing similar tasks suggest that the two mechanisms which control the excitability of this reflex pathway (i.e. fusimotor action and control of transmission at the muscle spindle to moto-neuron synapse) may be controlled independently.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

Directory of Open Access Journals (Sweden)

Snorri Donaldsson

Full Text Available The ability to determine airflow during nasal CPAP (NCPAP treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically.The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance.The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

Race walking gait and its influence on race walking economy in world-class race walkers.

Science.gov (United States)

Gomez-Ezeiza, Josu; Torres-Unda, Jon; Tam, Nicholas; Irazusta, Jon; Granados, Cristina; Santos-Concejero, Jordan

2018-03-06

The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h -1 , where race walking economy (ml·kg -1 ·km -1 ) and spatiotemporal gait variables were analysed at different speeds. 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05). According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.

Walking and child pedestrian injury: a systematic review of built environment correlates of safe walking.

Science.gov (United States)

Rothman, Linda; Buliung, Ron; Macarthur, Colin; To, Teresa; Howard, Andrew

2014-02-01

The child active transportation literature has focused on walking, with little attention to risk associated with increased traffic exposure. This paper reviews the literature related to built environment correlates of walking and pedestrian injury in children together, to broaden the current conceptualization of walkability to include injury prevention. Two independent searches were conducted focused on walking in children and child pedestrian injury within nine electronic databases until March, 2012. Studies were included which: 1) were quantitative 2) set in motorized countries 3) were either urban or suburban 4) investigated specific built environment risk factors 5) had outcomes of either walking in children and/or child pedestrian roadway collisions (ages 0-12). Built environment features were categorized according to those related to density, land use diversity or roadway design. Results were cross-tabulated to identify how built environment features associate with walking and injury. Fifty walking and 35 child pedestrian injury studies were identified. Only traffic calming and presence of playgrounds/recreation areas were consistently associated with more walking and less pedestrian injury. Several built environment features were associated with more walking, but with increased injury. Many features had inconsistent results or had not been investigated for either outcome. The findings emphasise the importance of incorporating safety into the conversation about creating more walkable cities.

Walking and Sensing Mobile Lives

DEFF Research Database (Denmark)

Bødker, Mads; Meinhardt, Nina Dam

In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk.......In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk....

Human treadmill walking needs attention

Directory of Open Access Journals (Sweden)

Daniel Olivier

2006-08-01

Full Text Available Abstract Background The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor task. Varying the level of difficulty of the reaction time (RT task is used to verify the priority of allocation of attentional resources. Methods 11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration. Results Gait cycle duration was unchanged (p > 0.05 by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p 0.05 was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance. Conclusion We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.

Breathing pattern and head posture: changes in craniocervical angles.

Science.gov (United States)

Sabatucci, A; Raffaeli, F; Mastrovincenzo, M; Luchetta, A; Giannone, A; Ciavarella, D

2015-04-01

The aim of this study was to observe the influence of oral breathing on head posture and to establish possible postural changes observing the variation of craniocervical angles NSL/OPT and NSL/CVT between oral breathing subjects and physiological breathing subjects. A cross-sectional study was conducted. The sample included 115 subject, 56 boys and 59 girls, 5-22-year-old. Among these, 80 were classified as oral breathers and 35 as physiological breathers. The diagnosis of oral breathing was carried out thanks to characteristic signs and symptoms evaluated on clinical examination, the analysis of characteristic X-ray images, ENT examination with active anterior rhinomanometric (AAR) test. The structural and postural analysis was carried out, calculating the craniofacial angles NSL/OPT and NSL/CVT. Both NSL/OPT and NSL/CVT appear to be significantly greater to those observed in physiological breathing patients. This means that patients who tend to breathe through the mouth rather than exclusively through the nose show a reduction of cervical lordosis and a proinclination of the head. Our study confirms that the oral breathing modifies head position. The significant increase of the craniocervical angles NSL/OPT and NSL/CVT in patients with this altered breathing pattern suggests an elevation of the head and a greater extension of the head compared with the cervical spine. So, to correct the breathing pattern early, either during childhood or during adolescence, can lead to a progressive normalization of craniofacial morphology and head posture.

'It was not just a walking experience': reflections on the role of care in dog-walking.

Science.gov (United States)

Degeling, Chris; Rock, Melanie

2013-09-01

Research into physical activity and human health has recently begun to attend to dog-walking. This study extends the literature on dog-walking as a health behaviour by conceptualizing dog-walking as a caring practice. It centres on qualitative interviews with 11 Canadian dog-owners. All participants resided in urban neighbourhoods identified through previous quantitative research as conducive to dog-walking. Canine characteristics, including breed and age, were found to influence people's physical activity. The health of the dog and its position in the life-course influenced patterns of dog-walking. Frequency, duration and spatial patterns of dog-walking all depended on relationships and people's capacity to tap into resources. In foregrounding networks of care, inclusive of pets and public spaces, a relational conceptualization of dog-walking as a practice of caring helps to make sense of heterogeneity in patterns of physical activity among dog-owners.

Pedestrian Walking Behavior Revealed through a Random Walk Model

Directory of Open Access Journals (Sweden)

Hui Xiong

2012-01-01

Full Text Available This paper applies method of continuous-time random walks for pedestrian flow simulation. In the model, pedestrians can walk forward or backward and turn left or right if there is no block. Velocities of pedestrian flow moving forward or diffusing are dominated by coefficients. The waiting time preceding each jump is assumed to follow an exponential distribution. To solve the model, a second-order two-dimensional partial differential equation, a high-order compact scheme with the alternating direction implicit method, is employed. In the numerical experiments, the walking domain of the first one is two-dimensional with two entrances and one exit, and that of the second one is two-dimensional with one entrance and one exit. The flows in both scenarios are one way. Numerical results show that the model can be used for pedestrian flow simulation.

Sensing the effects of mouth breathing by using 3-tesla MRI

Science.gov (United States)

Park, Chan-A.; Kang, Chang-Ki

2017-06-01

We investigated the effects of mouth breathing and typical nasal breathing on brain function by using blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI). The study had two parts: the first test was a simple contrast between mouth and nasal breathing, and the second test involved combined breathing modes, e.g., mouth inspiration and nasal expiration. Eleven healthy participants performed the combined breathing task while undergoing 3T fMRI. In the group-level analysis, contrast images acquired by using an individual participantlevel analysis were processed using the one-sample t test. We also conducted a region-of-interest analysis comparing signal intensity changes between the breathing modes; the region was selected using an automated anatomical labeling map. The results demonstrated that the BOLD signal in the hippocampus and brainstem was significantly decreased in mouth breathing relative to nasal breathing. On the other hand, both the precentral and postcentral gyri showed activation that was more significant in mouth breathing compared to nasal breathing. This study suggests that the BOLD activity patterns between mouth and nasal breathing may be induced differently, especially in the hippocampus, which could provide clues to explain the effects on brain cognitive function due to mouth breathing.

ACTIVE CYCLE BREATHING TECHNIQUES IN HEART FAILURE ...

African Journals Online (AJOL)

RICHY

Pulmonary Function Responses to Active Cycle. Breathing ... Key Words: Heart Failure, Active Cycle of Breathing ... cough, fatigue, reduced respiratory muscle mass, and. [5] ... an amount of exercise which is said to lower disease. [9].

Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking.

Directory of Open Access Journals (Sweden)

Barbara Pellegrini

Full Text Available Nordic Walking (NW owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W. Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2 performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2 were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking.

Science.gov (United States)

Pellegrini, Barbara; Peyré-Tartaruga, Leonardo Alexandre; Zoppirolli, Chiara; Bortolan, Lorenzo; Bacchi, Elisabetta; Figard-Fabre, Hélène; Schena, Federico

2015-01-01

Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

Quantum walks based on an interferometric analogy

International Nuclear Information System (INIS)

Hillery, Mark; Bergou, Janos; Feldman, Edgar

2003-01-01

There are presently two models for quantum walks on graphs. The ''coined'' walk uses discrete-time steps, and contains, besides the particle making the walk, a second quantum system, the coin, that determines the direction in which the particle will move. The continuous walk operates with continuous time. Here a third model for quantum walks is proposed, which is based on an analogy to optical interferometers. It is a discrete-time model, and the unitary operator that advances the walk one step depends only on the local structure of the graph on which the walk is taking place. This type of walk also allows us to introduce elements, such as phase shifters, that have no counterpart in classical random walks. Several examples are discussed

Regional integration in Central Asia: From knowing-that to knowing-how

Directory of Open Access Journals (Sweden)

Ulugbek Azizov

2017-07-01

Full Text Available The paper examines regional integration in Central Asia in the context of two types of knowledge, that is, knowing-that and knowing-how. While knowing-that prioritizes representational (i.e. “talking” practices of actors to explain region-building processes, knowing-how focuses on non-representational (i.e. “doing” practices. The article demonstrates that the orthodox scholars, who deal with the region of Central Asia, mostly employ knowing-that to explain region-building processes. The article criticizes knowing-that, assuming that this type of knowledge limits our understanding with regard to how regions get their boundaries and symbolism in the era of globalization and standardization of sectoral activities. Thus the article develops and introduces an alternative knowing-how framework to better understand the region-building processes in Central Asia and beyond it.

Blue breath holding is benign.

OpenAIRE

Stephenson, J B

1991-01-01

In their recent publication in this journal, Southall et al described typical cyanotic breath holding spells, both in otherwise healthy children and in those with brainstem lesions and other malformations. Their suggestions regarding possible autonomic disturbances may require further study, but they have adduced no scientific evidence to contradict the accepted view that in the intact child blue breath holding spells are benign. Those families in which an infant suffers an 'apparently life t...

Equivalence of Szegedy's and coined quantum walks

Science.gov (United States)

Wong, Thomas G.

2017-09-01

Szegedy's quantum walk is a quantization of a classical random walk or Markov chain, where the walk occurs on the edges of the bipartite double cover of the original graph. To search, one can simply quantize a Markov chain with absorbing vertices. Recently, Santos proposed two alternative search algorithms that instead utilize the sign-flip oracle in Grover's algorithm rather than absorbing vertices. In this paper, we show that these two algorithms are exactly equivalent to two algorithms involving coined quantum walks, which are walks on the vertices of the original graph with an internal degree of freedom. The first scheme is equivalent to a coined quantum walk with one walk step per query of Grover's oracle, and the second is equivalent to a coined quantum walk with two walk steps per query of Grover's oracle. These equivalences lie outside the previously known equivalence of Szegedy's quantum walk with absorbing vertices and the coined quantum walk with the negative identity operator as the coin for marked vertices, whose precise relationships we also investigate.

Aspiration tests in aqueous foam using a breathing simulator

Energy Technology Data Exchange (ETDEWEB)

Archuleta, M.M.

1995-12-01

Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

Rhythmic walking interactions with auditory feedback

DEFF Research Database (Denmark)

Jylhä, Antti; Serafin, Stefania; Erkut, Cumhur

2012-01-01

of interactions based on varying the temporal characteristics of the output, using the sound of human walking as the input. The system either provides a direct synthesis of a walking sound based on the detected amplitude envelope of the user's footstep sounds, or provides a continuous synthetic walking sound...... as a stimulus for the walking human, either with a fixed tempo or a tempo adapting to the human gait. In a pilot experiment, the different interaction modes are studied with respect to their effect on the walking tempo and the experience of the subjects. The results tentatively outline different user profiles......Walking is a natural rhythmic activity that has become of interest as a means of interacting with software systems such as computer games. Therefore, designing multimodal walking interactions calls for further examination. This exploratory study presents a system capable of different kinds...

Practical recommendations for breathing-adapted radiotherapy

International Nuclear Information System (INIS)

Simon, L.; Giraud, P.; Rosenwald, J.C.; Dumas, J.L.; Lorchel, F.; Marre, D.; Dupont, S.; Varmenot, N.; Ginestet, C.; Caron, J.; Marchesi, V.; Ferreira, I.; Garcia, R.

2007-01-01

Respiration-gated radiotherapy offers a significant potential for improvement in the irradiation of tumor sites affected by respiratory motion such as lung, breast and liver tumors. An increased conformality of irradiation fields leading to decreased complications rates of organs at risk (lung, heart) is expected. Respiratory gating is in line with the need for improved precision required by radiotherapy techniques such as 3D conformal radiotherapy or intensity modulated radiotherapy. Reduction of respiratory motion can be achieved by using either breath-hold techniques or respiration synchronized gating techniques. Breath-hold techniques can be achieved with active techniques, in which airflow of the patient is temporarily blocked by a valve, or passive techniques, in which the patient voluntarily holds his/her breath. Synchronized gating techniques use external devices to predict the phase of the respiration cycle while the patient breaths freely. This work summarizes the different experiences of the centers of the STIC 2003 project. It describes the different techniques, gives an overview of the literature and proposes a practice based on our experience. (authors)

Breathing and Relaxation

Science.gov (United States)

... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

Shortness of Breath

Science.gov (United States)

... filled with air (called pneumotho- rax), it will hinder expansion of the lung, resulting in shortness of ... of Chest Physi- cians. Shortness of Breath: Patient Education. http: / / www. onebreath. org/ document. doc? id= 113. ...

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion.

Science.gov (United States)

Kerkum, Yvette L; Buizer, Annemieke I; van den Noort, Josien C; Becher, Jules G; Harlaar, Jaap; Brehm, Merel-Anne

2015-01-01

Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (ppush-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power. Dutch Trial Register NTR3418.

Benefits of a Single-Person Spacecraft for Weightless Operations. [(Stop Walking and Start Flying)

Science.gov (United States)

Griffin, Brand N.

2012-01-01

Historically, less than 20 percent of crew time related to extravehicular activity (EVA) is spent on productive external work.1 A single-person spacecraft with 90 percent efficiency provides productive new capabilities for maintaining the International Space Station (ISS), exploring asteroids, and servicing telescopes or satellites. With suits, going outside to inspect, service or repair a spacecraft is time-consuming, requiring pre-breathe time, donning a fitted space suit, and pumping down an airlock. For ISS, this is between 12.5 and 16 hours for each EVA, not including translation and work-site set up. The work is physically demanding requiring a day of rest between EVAs and often results in suit-induced trauma with frequent injury to astronauts fingers2. For maximum mobility, suits use a low pressure, pure oxygen atmosphere. This represents a fire hazard and requires pre-breathing to reduce the risk of decompression sickness (bends). With virtually no gravity, humans exploring asteroids cannot use legs for walking. The Manned Maneuvering Unit offers a propulsive alternative however it is no longer in NASA s flight inventory. FlexCraft is a single person spacecraft operating at the same cabin atmosphere as its host so there is no risk of the bends and no pre-breathing. This allows rapid, any-time access to space for repeated short or long EVAs by different astronauts. Integrated propulsion eliminates hand-over-hand translation or having another crew member operate the robotic arm. The one-size-fits-all FlexCraft interior eliminates the suit part inventory and crew time required to fit all astronauts. With a shirtsleeve cockpit, conventional displays and controls are used and because the work is not strenuous no rest days are required. Furthermore, there is no need for hand tools because manipulators are equipped with force multiplying end-effectors that can deliver the precise torque for the job.

How Does a Hopping Kangaroo Breathe?

Science.gov (United States)

Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

2010-01-01

We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

Teacher Knowing or Not Knowing about Students

Science.gov (United States)

Amin, Nyna; Vithal, Renuka

2015-01-01

Based on a critical ethnography of an urban high school that exemplifies the many changes of post-apartheid South Africa, this paper presents data about two teachers who propose opposing perspectives and practices of knowing students. The analysis of the teachers' narratives shows that they came to know their students through solicited,…

Mapleson's Breathing Systems.

Science.gov (United States)

Kaul, Tej K; Mittal, Geeta

2013-09-01

Mapleson breathing systems are used for delivering oxygen and anaesthetic agents and to eliminate carbon dioxide during anaesthesia. They consist of different components: Fresh gas flow, reservoir bag, breathing tubes, expiratory valve, and patient connection. There are five basic types of Mapleson system: A, B, C, D and E depending upon the different arrangements of these components. Mapleson F was added later. For adults, Mapleson A is the circuit of choice for spontaneous respiration where as Mapleson D and its Bains modifications are best available circuits for controlled ventilation. For neonates and paediatric patients Mapleson E and F (Jackson Rees modification) are the best circuits. In this review article, we will discuss the structure of the circuits and functional analysis of various types of Mapleson systems and their advantages and disadvantages.

Mitochondrial citrulline synthesis from ammonia and glutamine in the liver of ureogenic air-breathing catfish, Clarias batrachus (Linnaeus).

Science.gov (United States)

Kharbuli, Zaiba Y; Biswas, Kuheli; Saha, Nirmalendu

2007-12-01

The possible synthesis of citrulline, a rate limiting step for urea synthesis via the ornithine-urea cycle (OUC) in teleosts was tested both in the presence of ammonia and glutamine as nitrogen-donating substrates by the isolated liver mitochondria of ureogenic air-breathing walking catfish, C. batrachus. Both ammonia and glutamine could be used as nitrogen-donating substrates for the synthesis of citrulline by the isolated liver mitochondria, since the rate of citrulline synthesis was almost equal in presence of both the substrates. The citrulline synthesis by the isolated liver mitochondria requires succinate at a concentration of 0.1 mM as an energy source, and also requires the involvement of intramitochondrial carbonic anhydrase activity for supplying HCO3 as another substrate for citrulline synthesis. The rate of citrulline synthesis was further stimulated significantly by the isolated liver mitochondria of the fish after pre-exposure to 25 mM NH4Cl for 7 days. Due to possessing this biochemical adaptational strategy leading to the amelioration of ammonia toxicity mainly by channeling ammonia directly and/or via the formation of glutamine to the OUC, this air-breathing catfish could succeed in surviving in high external ammonia, which it faces in its natural habitat in certain seasons of the year.

Consumer preference in ranking walking function utilizing the walking index for spinal cord injury II.

Science.gov (United States)

Patrick, M; Ditunno, P; Ditunno, J F; Marino, R J; Scivoletto, G; Lam, T; Loffree, J; Tamburella, F; Leiby, B

2011-12-01

Blinded rank ordering. To determine consumer preference in walking function utilizing the walking Index for spinal cord injury II (WISCI II) in individuals with spinal cord injury (SCI)from the Canada, the Italy and the United States of America. In all, 42 consumers with incomplete SCI (25 cervical, 12 thoracic, 5 lumbar) from Canada (12/42), Italy (14/42) and the United States of America (16/42) ranked the 20 levels of the WISCI II scale by their individual preference for walking. Subjects were blinded to the original ranking of the WISCI II scale by clinical scientists. Photographs of each WISCI II level used in a previous pilot study were randomly shuffled and rank ordered. Percentile, conjoint/cluster and graphic analyses were performed. All three analyses illustrated consumer ranking followed a bimodal distribution. Ranking for two levels with physical assistance and two levels with a walker were bimodal with a difference of five to six ranks between consumer subgroups (quartile analysis). The larger cluster (N=20) showed preference for walking with assistance over the smaller cluster (N=12), whose preference was walking without assistance and more devices. In all, 64% (27/42) of consumers ranked WISCI II level with no devices or braces and 1 person assistance higher than multiple levels of the WISCI II requiring no assistance. These results were unexpected, as the hypothesis was that consumers would rank independent walking higher than walking with assistance. Consumer preference for walking function should be considered in addition to objective measures in designing SCI trials that use significant improvement in walking function as an outcome measure.

Quantum walks on quotient graphs

International Nuclear Information System (INIS)

Krovi, Hari; Brun, Todd A.

2007-01-01

A discrete-time quantum walk on a graph Γ is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup H of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup H used to construct it. The quotient graph is constructed by removing the symmetries of the subgroup H from the original graph. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A 74, 042334 (2006)] that the hitting time for certain initial states of a quantum walks can be infinite, in contrast to classical random walks. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with hitting times which are short compared to classical random walks correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speedup

Quantum walks with infinite hitting times

International Nuclear Information System (INIS)

Krovi, Hari; Brun, Todd A.

2006-01-01

Hitting times are the average time it takes a walk to reach a given final vertex from a given starting vertex. The hitting time for a classical random walk on a connected graph will always be finite. We show that, by contrast, quantum walks can have infinite hitting times for some initial states. We seek criteria to determine if a given walk on a graph will have infinite hitting times, and find a sufficient condition, which for discrete time quantum walks is that the degeneracy of the evolution operator be greater than the degree of the graph. The set of initial states which give an infinite hitting time form a subspace. The phenomenon of infinite hitting times is in general a consequence of the symmetry of the graph and its automorphism group. Using the irreducible representations of the automorphism group, we derive conditions such that quantum walks defined on this graph must have infinite hitting times for some initial states. In the case of the discrete walk, if this condition is satisfied the walk will have infinite hitting times for any choice of a coin operator, and we give a class of graphs with infinite hitting times for any choice of coin. Hitting times are not very well defined for continuous time quantum walks, but we show that the idea of infinite hitting-time walks naturally extends to the continuous time case as well

Optimal speeds for walking and running, and walking on a moving walkway.

Science.gov (United States)

Srinivasan, Manoj

2009-06-01

Many aspects of steady human locomotion are thought to be constrained by a tendency to minimize the expenditure of metabolic cost. This paper has three parts related to the theme of energetic optimality: (1) a brief review of energetic optimality in legged locomotion, (2) an examination of the notion of optimal locomotion speed, and (3) an analysis of walking on moving walkways, such as those found in some airports. First, I describe two possible connotations of the term "optimal locomotion speed:" that which minimizes the total metabolic cost per unit distance and that which minimizes the net cost per unit distance (total minus resting cost). Minimizing the total cost per distance gives the maximum range speed and is a much better predictor of the speeds at which people and horses prefer to walk naturally. Minimizing the net cost per distance is equivalent to minimizing the total daily energy intake given an idealized modern lifestyle that requires one to walk a given distance every day--but it is not a good predictor of animals' walking speeds. Next, I critique the notion that there is no energy-optimal speed for running, making use of some recent experiments and a review of past literature. Finally, I consider the problem of predicting the speeds at which people walk on moving walkways--such as those found in some airports. I present two substantially different theories to make predictions. The first theory, minimizing total energy per distance, predicts that for a range of low walkway speeds, the optimal absolute speed of travel will be greater--but the speed relative to the walkway smaller--than the optimal walking speed on stationary ground. At higher walkway speeds, this theory predicts that the person will stand still. The second theory is based on the assumption that the human optimally reconciles the sensory conflict between the forward speed that the eye sees and the walking speed that the legs feel and tries to equate the best estimate of the forward

High on walking

DEFF Research Database (Denmark)

Woythal, Bente Martinsen; Haahr, Anita; Dreyer, Pia

2018-01-01

a leg, and people who live with Parkinson’s disease. The analysis of the data is inspired by Paul Ricoeur’s philosophy of interpretation. Four themes were identified: (a) I feel high in two ways; (b) Walking has to be automatic; (c) Every Monday, I walk with the girls in the park; and (d) I dream...

A fully integrated standalone portable cavity ringdown breath acetone analyzer

Science.gov (United States)

Sun, Meixiu; Jiang, Chenyu; Gong, Zhiyong; Zhao, Xiaomeng; Chen, Zhuying; Wang, Zhennan; Kang, Meiling; Li, Yingxin; Wang, Chuji

2015-09-01

Breath analysis is a promising new technique for nonintrusive disease diagnosis and metabolic status monitoring. One challenging issue in using a breath biomarker for potential particular disease screening is to find a quantitative relationship between the concentration of the breath biomarker and clinical diagnostic parameters of the specific disease. In order to address this issue, we need a new instrument that is capable of conducting real-time, online breath analysis with high data throughput, so that a large scale of clinical test (more subjects) can be achieved in a short period of time. In this work, we report a fully integrated, standalone, portable analyzer based on the cavity ringdown spectroscopy technique for near-real time, online breath acetone measurements. The performance of the portable analyzer in measurements of breath acetone was interrogated and validated by using the certificated gas chromatography-mass spectrometry. The results show that this new analyzer is useful for reliable online (online introduction of a breath sample without pre-treatment) breath acetone analysis with high sensitivity (57 ppb) and high data throughput (one data per second). Subsequently, the validated breath analyzer was employed for acetone measurements in 119 human subjects under various situations. The instrument design, packaging, specifications, and future improvements were also described. From an optical ringdown cavity operated by the lab-set electronics reported previously to this fully integrated standalone new instrument, we have enabled a new scientific tool suited for large scales of breath acetone analysis and created an instrument platform that can even be adopted for study of other breath biomarkers by using different lasers and ringdown mirrors covering corresponding spectral fingerprints.

A fully integrated standalone portable cavity ringdown breath acetone analyzer.

Science.gov (United States)

Sun, Meixiu; Jiang, Chenyu; Gong, Zhiyong; Zhao, Xiaomeng; Chen, Zhuying; Wang, Zhennan; Kang, Meiling; Li, Yingxin; Wang, Chuji

2015-09-01

Breath analysis is a promising new technique for nonintrusive disease diagnosis and metabolic status monitoring. One challenging issue in using a breath biomarker for potential particular disease screening is to find a quantitative relationship between the concentration of the breath biomarker and clinical diagnostic parameters of the specific disease. In order to address this issue, we need a new instrument that is capable of conducting real-time, online breath analysis with high data throughput, so that a large scale of clinical test (more subjects) can be achieved in a short period of time. In this work, we report a fully integrated, standalone, portable analyzer based on the cavity ringdown spectroscopy technique for near-real time, online breath acetone measurements. The performance of the portable analyzer in measurements of breath acetone was interrogated and validated by using the certificated gas chromatography-mass spectrometry. The results show that this new analyzer is useful for reliable online (online introduction of a breath sample without pre-treatment) breath acetone analysis with high sensitivity (57 ppb) and high data throughput (one data per second). Subsequently, the validated breath analyzer was employed for acetone measurements in 119 human subjects under various situations. The instrument design, packaging, specifications, and future improvements were also described. From an optical ringdown cavity operated by the lab-set electronics reported previously to this fully integrated standalone new instrument, we have enabled a new scientific tool suited for large scales of breath acetone analysis and created an instrument platform that can even be adopted for study of other breath biomarkers by using different lasers and ringdown mirrors covering corresponding spectral fingerprints.

Disorder and decoherence in coined quantum walks

International Nuclear Information System (INIS)

Zhang Rong; Qin Hao; Tang Bao; Xue Peng

2013-01-01

This article aims to provide a review on quantum walks. Starting form a basic idea of discrete-time quantum walks, we will review the impact of disorder and decoherence on the properties of quantum walks. The evolution of the standard quantum walks is deterministic and disorder introduces randomness to the whole system and change interference pattern leading to the localization effect. Whereas, decoherence plays the role of transmitting quantum walks to classical random walks. (topical review - quantum information)

Neighborhood Walking and Social Capital: The Correlation between Walking Experience and Individual Perception of Social Capital

Directory of Open Access Journals (Sweden)

Heechul Kim

2017-04-01

Full Text Available The purpose of this study was to analyze the relationship between people’s actual walking experience and their social capital levels in order to examine the possibility of restoring weakened social functions of streets and public spaces in a walking-friendly urban environment. Based on the survey data of 591 residents of Seoul, we empirically analyzed the relationship between walking experience for various purposes and individual perceptions of social capital using one-way ANOVA and OLS regression models. As a result of the analysis, we found that the levels of neighborly trust and networking of people who experienced leisure walking were higher than those of people who did not, while there was no difference in the level of social capital according to walking experiences for other purposes. This result is significant in that it shows the basis for the restoration of the social function of neighborhoods through social capital formation of people as an effect of walking. Hence, it is important to create a walking environment that supports leisure activities.

Walking on four limbs: A systematic review of Nordic Walking in Parkinson disease.

Science.gov (United States)

Bombieri, Federica; Schena, Federico; Pellegrini, Barbara; Barone, Paolo; Tinazzi, Michele; Erro, Roberto

2017-05-01

Nordic Walking is a relatively high intensity activity that is becoming increasingly popular. It involves marching using poles adapted from cross-country skiing poles in order to activate upper body muscles that would not be used during normal walking. Several studies have been performed using this technique in Parkinson disease patients with contradictory results. Thus, we reviewed here all studies using this technique in Parkinson disease patients and further performed a meta-analysis of RCTs where Nordic Walking was evaluated against standard medical care or other types of physical exercise. Nine studies including four RCTs were reviewed for a total of 127 patients who were assigned to the Nordic Walking program. The majority of studies reported beneficial effects of Nordic Walking on either motor or non-motor variables, but many limitations were observed that hamper drawing definitive conclusions and it is largely unclear whether the benefits persist over time. It would appear that little baseline disability is the strongest predictor of response. The meta-analysis of the 4 RCTs yielded a statistically significant reduction of the UPDRS-3 score, but its value of less than 1 point does not appear to be clinically meaningful. Well-designed, large RCTs should be performed both against standard medical care and other types of physical exercise to definitively address whether Nordic Walking can be beneficial in PD. Copyright © 2017. Published by Elsevier Ltd.

"Four legs instead of two"--perspectives on a Nordic walking-based walking programme among people with arthritis.

Science.gov (United States)

O'Donovan, Rhona; Kennedy, Norelee

2015-01-01

Nordic Walking (NW) is growing in popularity among people with arthritis. The aim of this study was to explore the perspectives of participants with arthritis on a NW-based walking programme including factors contributing to sustained participation in the programme. Three semi-structured focus groups were conducted with a total of 27 participants with various types of arthritis. The groups consisted of participants who completed a NW-based walking programme in the previous 4 years. Only participants who had sustained involvement in the walking group were included. Groups were audio-recorded, transcribed verbatim and thematic analysis was performed. Participants reported that the walking programme offered numerous benefits. Two distinct themes emerged: (1) "four legs instead of two legs" and (2) "a support group". Theme 1 incorporates the physical, psychological and educational benefits that stem from involvement in a walking group while Theme 2 incorporates the benefits of social support in group-based activity. Several benefits of a NW-based walking programme from the perspectives of individuals with arthritis who engage in group-based walking programmes were identified. The benefits may encourage sustained participation and justify the promotion of NW as an intervention for people with arthritis. Considering how to sustain exercise participation is important to ensure continued benefits from physical activity participation. A community-based Nordic walking-based walking programme for people with arthritis improved exercise knowledge and confidence to exercise. Group exercise is valuable in providing support and motivation to continue exercising.

Walking on fractals: diffusion and self-avoiding walks on percolation clusters

International Nuclear Information System (INIS)

Blavatska, V; Janke, W

2009-01-01

We consider random walks (RWs) and self-avoiding walks (SAWs) on disordered lattices directly at the percolation threshold. Applying numerical simulations, we study the scaling behavior of the models on the incipient percolation cluster in space dimensions d = 2, 3, 4. Our analysis yields estimates of universal exponents, governing the scaling laws for configurational properties of RWs and SAWs

Breath-Holding Spells

Science.gov (United States)

... reviewed: October 2016 More on this topic for: Parents Is It Normal for Children to Hold Their Breath? Taming Tempers Disciplining Your Child Disciplining Your Toddler Temper Tantrums Separation Anxiety View more About Us Contact Us Partners ...

Physical implementation of quantum walks

CERN Document Server

Manouchehri, Kia

2013-01-01

Given the extensive application of random walks in virtually every science related discipline, we may be at the threshold of yet another problem solving paradigm with the advent of quantum walks. Over the past decade, quantum walks have been explored for their non-intuitive dynamics, which may hold the key to radically new quantum algorithms. This growing interest has been paralleled by a flurry of research into how one can implement quantum walks in laboratories. This book presents numerous proposals as well as actual experiments for such a physical realization, underpinned by a wide range of

Progress of air-breathing cathode in microbial fuel cells

Science.gov (United States)

Wang, Zejie; Mahadevan, Gurumurthy Dummi; Wu, Yicheng; Zhao, Feng

2017-07-01

Microbial fuel cell (MFC) is an emerging technology to produce green energy and vanquish the effects of environmental contaminants. Cathodic reactions are vital for high electrical power density generated from MFCs. Recently tremendous attentions were paid towards developing high performance air-breathing cathodes. A typical air-breathing cathode comprises of electrode substrate, catalyst layer, and air-diffusion layer. Prior researches demonstrated that each component influenced the performance of air-breathing cathode MFCs. This review summarized the progress in development of the individual component and elaborated main factors to the performance of air-breathing cathode.

Treadmill walking with body weight support

OpenAIRE

Aaslund, Mona Kristin

2012-01-01

Background: Rehabilitating walking in patients post-stroke with safe, task-specific, intensive training of sufficient duration, can be challenging. Body weight supported treadmill training (BWSTT) has been proposed as an effective method to meet these challenges and may therefore have benefits over training overground walking. However, walking characteristics should not be aggravated during BWSTT or require a long familiarisation time compared to overground walking. Objectives: To investi...

Interlimb coordination during forward walking is largely preserved in backward walking in children with cerebral palsy

NARCIS (Netherlands)

Meyns, P.; Molenaers, G.; Desloovere, K.; Duysens, J.E.J.

2014-01-01

OBJECTIVE: Limb kinematics in backward walking (BW) are essentially those of forward walking (FW) in reverse. It has been argued that subcortical mechanisms could underlie both walking modes. METHODS: Therefore, we tested whether participants with supraspinal/cortical deficits (i.e. cerebral palsy)

More Adults Are Walking

Centers for Disease Control (CDC) Podcasts

This podcast is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.

A Passive Dynamic Walking Model Based on Knee-Bend Behaviour: Stability and Adaptability for Walking down Steep Slopes

Directory of Open Access Journals (Sweden)

Kang An

2013-10-01

Full Text Available This paper presents a passive dynamic walking model based on knee-bend behaviour, which is inspired by the way human beings walk. The length and mass parameters of human beings are used in the walking model. The knee-bend mechanism of the stance leg is designed in the phase between knee-strike and heel-strike. q* which is the angular difference of the stance leg between the two events, knee-strike and knee-bend, is adjusted in order to find a stable walking motion. The results show that the stable periodic walking motion on a slope of r <0.4 can be found by adjusting q*. Furthermore, with a particular q* in the range of 0.12walk down more steps before falling down on an arbitrary slope. The walking motion is more stable and adaptable than the conventional walking motion, especially for steep slopes.

Sleep-disordered breathing and mortality: a prospective cohort study.

Directory of Open Access Journals (Sweden)

Naresh M Punjabi

2009-08-01

Full Text Available Sleep-disordered breathing is a common condition associated with adverse health outcomes including hypertension and cardiovascular disease. The overall objective of this study was to determine whether sleep-disordered breathing and its sequelae of intermittent hypoxemia and recurrent arousals are associated with mortality in a community sample of adults aged 40 years or older.We prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in 6,441 men and women participating in the Sleep Heart Health Study. Sleep-disordered breathing was assessed with the apnea-hypopnea index (AHI based on an in-home polysomnogram. Survival analysis and proportional hazards regression models were used to calculate hazard ratios for mortality after adjusting for age, sex, race, smoking status, body mass index, and prevalent medical conditions. The average follow-up period for the cohort was 8.2 y during which 1,047 participants (587 men and 460 women died. Compared to those without sleep-disordered breathing (AHI: or=30.0 events/h sleep-disordered breathing were 0.93 (95% CI: 0.80-1.08, 1.17 (95% CI: 0.97-1.42, and 1.46 (95% CI: 1.14-1.86, respectively. Stratified analyses by sex and age showed that the increased risk of death associated with severe sleep-disordered breathing was statistically significant in men aged 40-70 y (hazard ratio: 2.09; 95% CI: 1.31-3.33. Measures of sleep-related intermittent hypoxemia, but not sleep fragmentation, were independently associated with all-cause mortality. Coronary artery disease-related mortality associated with sleep-disordered breathing showed a pattern of association similar to all-cause mortality.Sleep-disordered breathing is associated with all-cause mortality and specifically that due to coronary artery disease, particularly in men aged 40-70 y with severe sleep-disordered breathing. Please see later in the article for the Editors' Summary.

Increased Prevalence of Sleep-Disordered Breathing in Adults

Science.gov (United States)

Peppard, Paul E.; Young, Terry; Barnet, Jodi H.; Palta, Mari; Hagen, Erika W.; Hla, Khin Mae

2013-01-01

Sleep-disordered breathing is a common disorder with a range of harmful sequelae. Obesity is a strong causal factor for sleep-disordered breathing, and because of the ongoing obesity epidemic, previous estimates of sleep-disordered breathing prevalence require updating. We estimated the prevalence of sleep-disordered breathing in the United States for the periods of 1988–1994 and 2007–2010 using data from the Wisconsin Sleep Cohort Study, an ongoing community-based study that was established in 1988 with participants randomly selected from an employed population of Wisconsin adults. A total of 1,520 participants who were 30–70 years of age had baseline polysomnography studies to assess the presence of sleep-disordered breathing. Participants were invited for repeat studies at 4-year intervals. The prevalence of sleep-disordered breathing was modeled as a function of age, sex, and body mass index, and estimates were extrapolated to US body mass index distributions estimated using data from the National Health and Nutrition Examination Survey. The current prevalence estimates of moderate to severe sleep-disordered breathing (apnea-hypopnea index, measured as events/hour, ≥15) are 10% (95% confidence interval (CI): 7, 12) among 30–49-year-old men; 17% (95% CI: 15, 21) among 50–70-year-old men; 3% (95% CI: 2, 4) among 30–49-year-old women; and 9% (95% CI: 7, 11) among 50–70 year-old women. These estimated prevalence rates represent substantial increases over the last 2 decades (relative increases of between 14% and 55% depending on the subgroup). PMID:23589584

Quantum walk on a chimera graph

Science.gov (United States)

Xu, Shu; Sun, Xiangxiang; Wu, Jizhou; Zhang, Wei-Wei; Arshed, Nigum; Sanders, Barry C.

2018-05-01

We analyse a continuous-time quantum walk on a chimera graph, which is a graph of choice for designing quantum annealers, and we discover beautiful quantum walk features such as localization that starkly distinguishes classical from quantum behaviour. Motivated by technological thrusts, we study continuous-time quantum walk on enhanced variants of the chimera graph and on diminished chimera graph with a random removal of vertices. We explain the quantum walk by constructing a generating set for a suitable subgroup of graph isomorphisms and corresponding symmetry operators that commute with the quantum walk Hamiltonian; the Hamiltonian and these symmetry operators provide a complete set of labels for the spectrum and the stationary states. Our quantum walk characterization of the chimera graph and its variants yields valuable insights into graphs used for designing quantum-annealers.

Dysfunctional breathing: a review of the literature and proposal for classification

Directory of Open Access Journals (Sweden)

Richard Boulding

2016-09-01

Full Text Available Dysfunctional breathing is a term describing breathing disorders where chronic changes in breathing pattern result in dyspnoea and other symptoms in the absence or in excess of the magnitude of physiological respiratory or cardiac disease. We reviewed the literature and propose a classification system for the common dysfunctional breathing patterns described. The literature was searched using the terms: dysfunctional breathing, hyperventilation, Nijmegen questionnaire and thoraco-abdominal asynchrony. We have summarised the presentation, assessment and treatment of dysfunctional breathing, and propose that the following system be used for classification. 1 Hyperventilation syndrome: associated with symptoms both related to respiratory alkalosis and independent of hypocapnia. 2 Periodic deep sighing: frequent sighing with an irregular breathing pattern. 3 Thoracic dominant breathing: can often manifest in somatic disease, if occurring without disease it may be considered dysfunctional and results in dyspnoea. 4 Forced abdominal expiration: these patients utilise inappropriate and excessive abdominal muscle contraction to aid expiration. 5 Thoraco-abdominal asynchrony: where there is delay between rib cage and abdominal contraction resulting in ineffective breathing mechanics. This review highlights the common abnormalities, current diagnostic methods and therapeutic implications in dysfunctional breathing. Future work should aim to further investigate the prevalence, clinical associations and treatment of these presentations.

Can audio coached 4D CT emulate free breathing during the treatment course?

International Nuclear Information System (INIS)

Persson, Gitte F.; Nygaard, Ditte E.; Olsen, Mikael; Juhler-Noettrup, Trine; Pedersen, Anders N.; Specht, Lena; Korreman, Stine S.

2008-01-01

Background. The image quality of 4DCT depends on breathing regularity. Respiratory audio coaching may improve regularity and reduce motion artefacts. We question the safety of coached planning 4DCT without coaching during treatment. We investigated the possibility of coaching to a more stable breathing without changing the breathing amplitude. The interfraction variation of the breathing cycle amplitude in free and coached breathing was studied as well as the possible impact of fatigue on longer coaching sessions. Methods. Thirteen volunteers completed respiratory audio coaching on 3 days within a 2 week period. An external marker system monitoring the motion of the thoraco-abdominal wall was used to track the respiration. On all days, free breathing and two coached breathing curves were recorded. We assumed that free versus coached breathing from day 1 (reference session) simulated breathing during an uncoached versus coached planning 4DCT, respectively, and compared the mean breathing cycle amplitude to the free versus coached breathing from day 2 and 3 simulating free versus coached breathing during treatment. Results. For most volunteers it was impossible to apply coaching without changes in breathing cycle amplitude. No significant decrease in standard deviation of breathing cycle amplitude distribution was seen. Generally it was not possible to predict the breathing cycle amplitude and its variation the following days based on the breathing in the reference session irrespective of coaching or free breathing. We found a significant tendency towards an increased breathing cycle amplitude variation with the duration of the coaching session. Conclusion. These results suggest that large interfraction variation is present in breathing amplitude irrespective of coaching, leading to the suggestion of daily image guidance for verification of respiratory pattern and tumour related motion. Until further investigated it is not recommendable to use coached 4DCT for

Can audio coached 4D CT emulate free breathing during the treatment course?

Energy Technology Data Exchange (ETDEWEB)

Persson, Gitte F.; Nygaard, Ditte E.; Olsen, Mikael; Juhler-Noettrup, Trine; Pedersen, Anders N.; Specht, Lena; Korreman, Stine S. (Dept. of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark))

2008-08-15

Background. The image quality of 4DCT depends on breathing regularity. Respiratory audio coaching may improve regularity and reduce motion artefacts. We question the safety of coached planning 4DCT without coaching during treatment. We investigated the possibility of coaching to a more stable breathing without changing the breathing amplitude. The interfraction variation of the breathing cycle amplitude in free and coached breathing was studied as well as the possible impact of fatigue on longer coaching sessions. Methods. Thirteen volunteers completed respiratory audio coaching on 3 days within a 2 week period. An external marker system monitoring the motion of the thoraco-abdominal wall was used to track the respiration. On all days, free breathing and two coached breathing curves were recorded. We assumed that free versus coached breathing from day 1 (reference session) simulated breathing during an uncoached versus coached planning 4DCT, respectively, and compared the mean breathing cycle amplitude to the free versus coached breathing from day 2 and 3 simulating free versus coached breathing during treatment. Results. For most volunteers it was impossible to apply coaching without changes in breathing cycle amplitude. No significant decrease in standard deviation of breathing cycle amplitude distribution was seen. Generally it was not possible to predict the breathing cycle amplitude and its variation the following days based on the breathing in the reference session irrespective of coaching or free breathing. We found a significant tendency towards an increased breathing cycle amplitude variation with the duration of the coaching session. Conclusion. These results suggest that large interfraction variation is present in breathing amplitude irrespective of coaching, leading to the suggestion of daily image guidance for verification of respiratory pattern and tumour related motion. Until further investigated it is not recommendable to use coached 4DCT for

SU-E-J-62: Breath Hold for Left-Sided Breast Cancer: Visually Monitored Deep Inspiration Breath Hold Amplitude Evaluated Using Real-Time Position Management

Energy Technology Data Exchange (ETDEWEB)

Conroy, L; Quirk, S; Smith, WL [The University of Calgary, Calgary, AB (Canada); Tom Baker Cancer Centre, Calgary, AB (Canada); Yeung, R; Phan, T [The University of Calgary, Calgary, AB (Canada); Hudson, A [Tom Baker Cancer Centre, Calgary, AB (Canada)

2015-06-15

Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams were delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients.

Establishing the Range of Perceptually Natural Visual Walking Speeds for Virtual Walking-In-Place Locomotion

DEFF Research Database (Denmark)

Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

2014-01-01

to virtual motion. This paper describes two within-subjects studies performed with the intention of establishing the range of perceptually natural walking speeds for WIP locomotion. In both studies, subjects performed a series of virtual walks while exposed to visual gains (optic flow multipliers) ranging...... from 1.0 to 3.0. Thus, the slowest speed was equal to an estimate of the subjects normal walking speed, while the highest speed was three times greater. The perceived naturalness of the visual speed was assessed using self-reports. The first study compared four different types of movement, namely...... proportional to the degree of underestimation of the virtual speeds for both treadmill-mediated virtual walking and WIP locomotion. Combined, the results constitute a first attempt at establishing a set of guidelines specifying what virtual walking speeds WIP gestures should produce in order to facilitate...

21 CFR 868.2375 - Breathing frequency monitor.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing frequency monitor. 868.2375 Section 868.2375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2375 Breathing frequency monitor. (a...

Variability in energy cost and walking gait during race walking in competitive race walkers.

Science.gov (United States)

Brisswalter, J; Fougeron, B; Legros, P

1998-09-01

The aim of this study was to examine the variability of energy cost (Cw) and race walking gait after a 3-h walk at the competition pace in race walkers of the same performance level. Nine competitive race walkers were studied. In the same week, after a first test of VO2max determination, each subject completed two submaximal treadmill walks (6 min length, 0% grade, 12 km X h(-1) speed) before and after a 3-h overground test completed at the individual competition speed of the race walker. During the two submaximal tests, subjects were filmed between the 2nd and the 4th min, and physiological parameters were recorded between the 4th and the 6th min. Results showed two trends. On the one hand, we observed a significant and systematic increase in energy cost of walking (mean deltaCw = 8.4%), whereas no variation in the gait kinematics prescribed by the rules of race walking was recorded. On the other hand, this increase in metabolic energy demand was accompanied by variations of different magnitude and direction of stride length, of the excursion of the heel and of the maximal ankle flexion at toe-off among the race walkers. These results indicated that competitive race walkers are able to maintain their walking gait with exercise duration apart from a systematic increase in energy cost. Moreover, in this form of locomotion the effect of fatigue on the gait variability seems to be an individual function of the race walk constraints and the constraints of the performer.

Effects of high-frequency yoga breathing called kapalabhati compared with breath awareness on the degree of optical illusion perceived.

Science.gov (United States)

Telles, Shirley; Maharana, Kanchan; Balrana, Budhi; Balkrishna, Acharya

2011-06-01

Prior research has shown that methods of meditation, breath control, and different kinds of yoga breathing affect attention and visual perception, including decreasing the size of certain optical illusions. Evaluating relationships sheds light on the perceptual and cognitive changes induced by yoga and related methods, and the locus of the effects. In the present study, the degree of optical illusion was assessed using Müller-Lyer stimuli before and immediately after two different kinds of practice, a high frequency yoga breathing called kapalabhati, and breath awareness. A nonyoga, control session tested for practice effects. Thirty participants (with group M age = 26.9 yr., SD = 5.7) practiced the two techniques for 18 min. on two separate days. The control group had 15 nonyoga practitioners assessed before and after 18 min. in which they did not perform any specific activity but were seated and relaxed. After both kapalabhati and breath awareness there was a significant decrease in the degree of optical illusion. The possibility that this was due to a practice or repetition effect was ruled out when 15 nonyoga practitioners showed no change in the degree of illusion when retested after 18 min. The changes were interpreted as due to changes in perception related to the way the stimuli were judged.

Motor modules in robot-aided walking

Directory of Open Access Journals (Sweden)

Gizzi Leonardo

2012-10-01

Full Text Available Abstract Background It is hypothesized that locomotion is achieved by means of rhythm generating networks (central pattern generators and muscle activation generating networks. This modular organization can be partly identified from the analysis of the muscular activity by means of factorization algorithms. The activity of rhythm generating networks is described by activation signals whilst the muscle intervention generating network is represented by motor modules (muscle synergies. In this study, we extend the analysis of modular organization of walking to the case of robot-aided locomotion, at varying speed and body weight support level. Methods Non Negative Matrix Factorization was applied on surface electromyographic signals of 8 lower limb muscles of healthy subjects walking in gait robotic trainer at different walking velocities (1 to 3km/h and levels of body weight support (0 to 30%. Results The muscular activity of volunteers could be described by low dimensionality (4 modules, as for overground walking. Moreover, the activation signals during robot-aided walking were bursts of activation timed at specific phases of the gait cycle, underlying an impulsive controller, as also observed in overground walking. This modular organization was consistent across the investigated speeds, body weight support level, and subjects. Conclusions These results indicate that walking in a Lokomat robotic trainer is achieved by similar motor modules and activation signals as overground walking and thus supports the use of robotic training for re-establishing natural walking patterns.

Usefulness of Guided Breathing for Dose Rate-Regulated Tracking

International Nuclear Information System (INIS)

Han-Oh, Sarah; Yi, Byong Yong; Berman, Barry L.; Lerma, Fritz; Yu, Cedric

2009-01-01

Purpose: To evaluate the usefulness of guided breathing for dose rate-regulated tracking (DRRT), a new technique to compensate for intrafraction tumor motion. Methods and Materials: DRRT uses a preprogrammed multileaf collimator sequence that tracks the tumor motion derived from four-dimensional computed tomography and the corresponding breathing signals measured before treatment. Because the multileaf collimator speed can be controlled by adjusting the dose rate, the multileaf collimator positions are adjusted in real time during treatment by dose rate regulation, thereby maintaining synchrony with the tumor motion. DRRT treatment was simulated with free, audio-guided, and audiovisual-guided breathing signals acquired from 23 lung cancer patients. The tracking error and duty cycle for each patient were determined as a function of the system time delay (range, 0-1.0 s). Results: The tracking error and duty cycle averaged for all 23 patients was 1.9 ± 0.8 mm and 92% ± 5%, 1.9 ± 1.0 mm and 93% ± 6%, and 1.8 ± 0.7 mm and 92% ± 6% for the free, audio-guided, and audiovisual-guided breathing, respectively, for a time delay of 0.35 s. The small differences in both the tracking error and the duty cycle with guided breathing were not statistically significant. Conclusion: DRRT by its nature adapts well to variations in breathing frequency, which is also the motivation for guided-breathing techniques. Because of this redundancy, guided breathing does not result in significant improvements for either the tracking error or the duty cycle when DRRT is used for real-time tumor tracking

Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

Directory of Open Access Journals (Sweden)

Matthew R Holdgate

Full Text Available Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33 and Asian (n = 23 elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

Science.gov (United States)

Holdgate, Matthew R; Meehan, Cheryl L; Hogan, Jennifer N; Miller, Lance J; Soltis, Joseph; Andrews, Jeff; Shepherdson, David J

2016-01-01

Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

The association between dog walking, physical activity and owner’s perceptions of safety: cross-sectional evidence from the US and Australia

Directory of Open Access Journals (Sweden)

Hayley Christian

2016-09-01

with a dog may be a mechanism for increasing perceptions of neighborhood safety and getting to know the neighborhood, however significant between-country differences exist. Further international research is required to understand the drivers for these between-country differences. Community based programs and policies aimed at improving safety and social connectedness should consider the wider community benefits of dog walking and include strategies for supporting more dog walking.

Quantum walks, quantum gates, and quantum computers

International Nuclear Information System (INIS)

Hines, Andrew P.; Stamp, P. C. E.

2007-01-01

The physics of quantum walks on graphs is formulated in Hamiltonian language, both for simple quantum walks and for composite walks, where extra discrete degrees of freedom live at each node of the graph. It is shown how to map between quantum walk Hamiltonians and Hamiltonians for qubit systems and quantum circuits; this is done for both single-excitation and multiexcitation encodings. Specific examples of spin chains, as well as static and dynamic systems of qubits, are mapped to quantum walks, and walks on hyperlattices and hypercubes are mapped to various gate systems. We also show how to map a quantum circuit performing the quantum Fourier transform, the key element of Shor's algorithm, to a quantum walk system doing the same. The results herein are an essential preliminary to a Hamiltonian formulation of quantum walks in which coupling to a dynamic quantum environment is included

The Act of Walking

DEFF Research Database (Denmark)

Vestergaard, Maria Quvang Harck; Olesen, Mette; Helmer, Pernille Falborg

2014-01-01

’ of mobility (Jensen 2013:111) such as the urban environment, and the infrastructures. Walking has indeed also a ‘software dimension’ as an embodied performance that trigger the human senses (Jensen 2013) and which is closely related to the habitus and identity of the individual (Halprin 1963). The individual......The ability to walk in an area is, in the existing literature, often explained by the physical structures like building density and the presence of facilities in an area, and it is often termed ‘walkability’ (Patton 2007; Forsyth and Southworth 2008; Krizek, Handy and Forsyth 2009; Johnson 2003......; Frumkin 2002). The term ‘walkability’ focuses on how the physical structures in the urban environment can promote walking, and how this potentially eases issues of public health and liveability in our cities (Krizek et al. 2009). However, the study of walking should not be reduced merely to the ‘hardware...

Submarines, spacecraft and exhaled breath.

Science.gov (United States)

Pleil, Joachim D; Hansel, Armin

2012-03-01

-term plans for their analytical tools, in this case to take breath analysis away from the large complex instruments in the laboratory to the outpatient clinic and eventually to the home care market. Similarly, for environmental and public health research, it is always desirable to have easily operated and deployable instruments that can be taken to the field, rather than bringing numerous subjects to a central laboratory. Bio-monitoring. Although the SAMAP community is much more focused on air rather than breath measurement, this is changing because of the realization that longer deployment times (on submarines and spacecraft) will affect more than just acute health. To monitor longer-term health outcomes, there is a great deal of commonality between our respective research communities. Any instrument that monitors for contaminants in environmental air could certainly be adapted to breath analysis for assessing exposures and health state. Instruments that simultaneously provide rapid response and high specificity to a broad range of analytes, such as those based on optical spectroscopy and mass spectrometry, are particularly valued. The path forward We found the SAMAP meeting to be a worthwhile experience, largely from the discovery that another high-tech community exists with similar needs as the IABR community. Some collaboration could be fruitful for us; we suggest that the IABR community stay in contact with SAMAP in the future and attempt to attend each other's meetings if possible. SAMAP meetings tend to run on a two year cycle and so the next one has not yet been announced. We will let the IABR community know when the next meeting is scheduled, and will certainly make the SAMAP people aware of IABR meetings and the Journal of Breath Research. This article has been subjected to EPA Agency review and approved for publication. Statements do not necessarily reflect official Agency policy.

Effects of Intermittent Versus Continuous Walking on Distance Walked and Fatigue in Persons With Multiple Sclerosis: A Randomized Crossover Trial.

Science.gov (United States)

Karpatkin, Herb; Cohen, Evan T; Rzetelny, Adam; Parrott, J Scott; Breismeister, Breanne; Hartman, Ryan; Luu, Ronald; Napolione, Danielle

2015-07-01

Fatigue is a common, disabling symptom experienced by persons with multiple sclerosis (MS). Evidence shows that intermittent exercise is associated in improved performance and negligible fatigue. The purpose of this study was to examine whether subjects with MS walk greater distances with less fatigue under intermittent (INT) or continuous (CONT) walking condition. Twenty-seven subjects with MS (median Extended Disability Severity Scale 3.5, interquartile range 1.6) walked in the CONT (ie, 6 uninterrupted minutes) and INT (ie, three 2-minute walking bouts) conditions in a randomized crossover. Distance was measured for the entire 6-minute walking period and each 2-minute increment. Fatigue was measured as the difference in a visual analog scale of fatigue (ΔVAS-F) immediately preceding and following each trial. Participants walked greater distances in the INT condition compared to the CONT condition (P = 0.005). There was a significant interaction of walking condition and time (P walked in the INT condition changed across time. ΔVAS-F was significantly lower in the INT condition than in the CONT condition (P = 0.036). Subjects with MS walked farther, and with less fatigue, when walking intermittently rather than continuously. Persons with MS may be able to tolerate a greater dose of walking training if the walking bouts are intermittent. Further study to determine the benefits of a walking exercise program using intermittent walking is recommended.Video Abstract available for additional insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A103).

Sleep-disordered breathing in epilepsy: epidemiology, mechanisms, and treatment.

Science.gov (United States)

Sivathamboo, Shobi; Perucca, Piero; Velakoulis, Dennis; Jones, Nigel C; Goldin, Jeremy; Kwan, Patrick; O'Brien, Terence J

2018-04-01

Epilepsy is a group of neurological conditions in which there is a pathological and enduring predisposition to generate recurrent seizures. Evidence over the last few decades suggests that epilepsy may be associated with increased sleep-disordered breathing, which may contribute towards sleep fragmentation, daytime somnolence, reduced seizure control, and cardiovascular-related morbidity and mortality. Chronic sleep-disordered breathing can result in loss of gray matter and cause deficits to memory and global cognitive function. Sleep-disordered breathing is a novel and independent predictor of sudden cardiac death and, as such, may be involved in the mechanisms leading to sudden unexpected death in epilepsy. Despite this, the long-term consequences of sleep-disordered breathing in epilepsy remain unknown, and there are no guidelines for screening or treating this population. There is currently insufficient evidence to indicate continuous positive airway pressure (CPAP) for the primary or secondary prevention of cardiovascular disease, and recent evidence has failed to show any reduction of fatal or nonfatal cardiovascular endpoints. Treatment of sleep-disordered breathing may potentially improve seizure control, daytime somnolence, and neurocognitive outcomes, but few studies have examined this relationship. In this review, we examine sleep-disordered breathing in epilepsy, and discuss the potential effect of epilepsy treatments. We consider the role of CPAP and other interventions for sleep-disordered breathing and discuss their implications for epilepsy management.

Race Differences: Use of Walking Speed to Identify Community-Dwelling Women at Risk for Poor Health Outcomes--Osteoarthritis Initiative Study.

Science.gov (United States)

Kirkness, Carmen S; Ren, Jinma

2015-07-01

Onset of disability, risk for future falls, frailty, functional decline, and mortality are strongly associated with a walking speed of less than 1.0 m/s. The study objective was to determine whether there were differences in slow walking speed (differences in walking speed can be attributed to age, obesity, socioeconomic factors, disease severity, or comorbidities. A cross-sectional design was used. Community-dwelling adults were recruited from Baltimore, Maryland; Columbus, Ohio; Pittsburgh, Pennsylvania; and Pawtucket, Rhode Island. Participants were 2,648 women (23% African American) who were 45 to 79 years of age and had a self-selected baseline walking speed of 20 m/s in the Osteoarthritis Initiative Study. Mixed-effects logistic regression models were used to examine racial differences in walking speed (<1.0 m/s versus ≥1.0 m/s), with adjustments for demographic factors, socioeconomic factors, disease severity, and comorbidities. Walking speed was significantly slower for African American women than for white American women (mean walking speed=1.19 and 1.33 m/s, respectively). The prevalence of a walking speed of less than 1.0 m/s in this cohort of middle-aged women was 9%; about 50% of the women with a walking speed of less than 1.0 m/s were younger than 65 years. Women with a walking speed of less than 1.0 m/s had lower values for socioeconomic factors, higher values for disease severity, and higher prevalences of obesity and comorbidities than those with a walking speed of ≥1.0 m/s. After controlling for these covariates, it was found that African American women were 3 times (odds ratio=2.9; 95% confidence interval=2.0, 4.1) more likely to have a walking speed of less than 1.0 m/s than white American women. The study design made it impossible to know whether a walking speed of less than 1.0 m/s in women who were 45 years of age or older was a predictor of future poor health outcomes. In this study, race was independently associated with a walking speed

Walking during body-weight-supported treadmill training and acute responses to varying walking speed and body-weight support in ambulatory patients post-stroke.

Science.gov (United States)

Aaslund, Mona Kristin; Helbostad, Jorunn Lægdheim; Moe-Nilssen, Rolf

2013-05-01

Rehabilitating walking in ambulatory patients post-stroke, with training that is safe, task-specific, intensive, and of sufficient duration, can be challenging. Some challenges can be met by using body-weight-supported treadmill training (BWSTT). However, it is not known to what degree walking characteristics are similar during BWSTT and overground walking. In addition, important questions regarding the training protocol of BWSTT remain unanswered, such as how proportion of body-weight support (BWS) and walking speed affect walking characteristics during training. The objective was therefore to investigate if and how kinematic walking characteristics are different between overground walking and treadmill walking with BWS in ambulatory patients post-stroke, and the acute response of altering walking speed and percent BWS during treadmill walking with BWS. A cross-sectional repeated-measures design was used. Ambulating patients post-stroke walked in slow, preferred, and fast walking speed overground and at comparable speeds on the treadmill with 20% and 40% BWS. Kinematic walking characteristics were obtained using a kinematic sensor attached over the lower back. Forty-four patients completed the protocol. Kinematic walking characteristics were similar during treadmill walking with BWS, compared to walking overground. During treadmill walking, choice of walking speed had greater impact on kinematic walking characteristics than proportion of BWS. Faster walking speeds tended to affect the kinematic walking characteristics positively. This implies that in order to train safely and with sufficient intensity and duration, therapists may choose to include BWSTT in walking rehabilitation also for ambulatory patients post-stroke without aggravating gait pattern during training.

Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy

Science.gov (United States)

Bartlett, Frederick R.; Colgan, Ruth M.; Donovan, Ellen M.; Carr, Karen; Landeg, Steven; Clements, Nicola; McNair, Helen A.; Locke, Imogen; Evans, Philip M.; Haviland, Joanne S.; Yarnold, John R.; Kirby, Anna M.

2014-01-01

Breath-holding techniques reduce the amount of radiation received by cardiac structures during tangential-field left breast radiotherapy. With these techniques, patients hold their breath while radiotherapy is delivered, pushing the heart down and away from the radiotherapy field. Despite clear dosimetric benefits, these techniques are not yet in widespread use. One reason for this is that commercially available solutions require specialist equipment, necessitating not only significant capital investment, but often also incurring ongoing costs such as a need for daily disposable mouthpieces. The voluntary breath-hold technique described here does not require any additional specialist equipment. All breath-holding techniques require a surrogate to monitor breath-hold consistency and whether breath-hold is maintained. Voluntary breath-hold uses the distance moved by the anterior and lateral reference marks (tattoos) away from the treatment room lasers in breath-hold to monitor consistency at CT-planning and treatment setup. Light fields are then used to monitor breath-hold consistency prior to and during radiotherapy delivery. PMID:25046661

Generalized atmospheric sampling of self-avoiding walks

International Nuclear Information System (INIS)

Van Rensburg, E J Janse; Rechnitzer, A

2009-01-01

In this paper, we introduce a new Monte Carlo method for sampling lattice self-avoiding walks. The method, which we call 'GAS' (generalized atmospheric sampling), samples walks along weighted sequences by implementing elementary moves generated by the positive, negative and neutral atmospheric statistics of the walks. A realized sequence is weighted such that the average weight of states of length n is proportional to the number of self-avoiding walks from the origin c n . In addition, the method also self-tunes to sample from uniform distributions over walks of lengths in an interval [0, n max ]. We show how to implement GAS using both generalized and endpoint atmospheres of walks and analyse our data to obtain estimates of the growth constant and entropic exponent of self-avoiding walks in the square and cubic lattices.

Nordic walking and chronic low back pain

DEFF Research Database (Denmark)

Morsø, Lars; Hartvigsen, Jan; Puggaard, Lis

2006-01-01

activity provide similar benefits. Nordic Walking is a popular and fast growing type of exercise in Northern Europe. Initial studies have demonstrated that persons performing Nordic Walking are able to exercise longer and harder compared to normal walking thereby increasing their cardiovascular metabolism....... Until now no studies have been performed to investigate whether Nordic Walking has beneficial effects in relation to low back pain. The primary aim of this study is to investigate whether supervised Nordic Walking can reduce pain and improve function in a population of chronic low back pain patients...... when compared to unsupervised Nordic Walking and advice to stay active. In addition we investigate whether there is an increase in the cardiovascular metabolism in persons performing supervised Nordic Walking compared to persons who are advised to stay active. Finally, we investigate whether...

Know Stroke: Know the Signs, Act in Time Video

Medline Plus

Full Text Available ... history of stroke. Dr. Galen Henderson, Harvard Medical School, Brigham and Women's Hospital: "Strokes are preventable, they ... University of Maryland Medical Center University of Maryland School of Medicine Know Stroke: Know the Signs. Act ...

Know Stroke: Know the Signs, Act in Time Video

Medline Plus

Full Text Available ... Know the Signs, Act in Time. Announcer: Most people know what to do in the case of ... you can do something." Announcer: In the past, people often struggled to live with serious disabilities after ...

Know Stroke: Know the Signs, Act in Time Video

Medline Plus

Full Text Available ... and Chairman, Neurology, University of Cincinnati College of Medicine Special Thanks to: The Shanley Family The Saxon ... Maryland Medical Center University of Maryland School of Medicine Know Stroke: Know the Signs. Act in Time. ...

Prevalence of Walking-Related Motor Fatigue in Persons With Multiple Sclerosis: Decline in Walking Distance Induced by the 6-Minute Walk Test.

Science.gov (United States)

Leone, Carmela; Severijns, Deborah; Doležalová, Vendula; Baert, Ilse; Dalgas, Ulrik; Romberg, Anders; Bethoux, Francois; Gebara, Benoit; Santoyo Medina, Carmen; Maamâgi, Heigo; Rasova, Kamila; Maertens de Noordhout, Benoît; Knuts, Kathy; Skjerbaek, Anders; Jensen, Ellen; Wagner, Joanne M; Feys, Peter

2016-05-01

To investigate the individual occurrence of walking-related motor fatigue in persons with multiple sclerosis (PwMS), according to disability level and disease phenotype.Study design This was a cross-sectional, multinational study.Participants They were 208 PwMS from 11 centers with Expanded Disability Status Scale (EDSS) scores up to 6.5. The percentage change in distance walked (distance walked index, DWI) was calculated between minute 6 and 1 (DWI(6-1)) of the 6-Minute Walk Test (6MWT). Its magnitude was used to classify participants into 4 subgroups: (1) DWI(6-1)[≥5%], (2) DWI(6-1)[5%; -5%], (3) DWI(6-1)[-5%; > -15%], and (4) DWI(6-1)[≤-15%]. The latter group was labeled as having walking-related motor fatigue. PwMS were stratified into 5 subgroups based on the EDSS (0-2.5, 3-4, 4.5-5.5, 6, 6.5) and 3 subgroups based on MS phenotype (relapsing remitting [RR], primary progressive [PP], and secondary progressive [SP]). The DWI6-1was ≥5% in 16 PwMS (7.7%), between 5% and -5% in 70 PwMS (33.6%), between -5% and -15% in 58 PwMS (24%), and ≤-15% in 64 PwMS (30.8%). The prevalence of walking-related motor fatigue (DWI(6-1)[≤-15%]) was significantly higher among the progressive phenotype (PP = 50% and SP = 39%; RR = 15.6%) and PwMS with higher disability level (EDSS 4.5-5.5 = 48.3%, 6 = 46.3% and 6.5 = 51.5%, compared with EDSS 0-2.5 = 7.8% and 3-4 = 16.7%;P< .05). Stepwise multiple regression analysis indicated that EDSS, but not MS phenotype, explained a significant part of the variance in DWI(6-1)(R(2)= 0.086;P< .001). More than one-third of PwMS showed walking-related motor fatigue during the 6MWT, with its prevalence greatest in more disabled persons (up to 51%) and in those with progressive MS phenotype (up to 50%). Identification of walking-related motor fatigue may lead to better-tailored interventions. © The Author(s) 2015.

Analysis of absorbing times of quantum walks

International Nuclear Information System (INIS)

Yamasaki, Tomohiro; Kobayashi, Hirotada; Imai, Hiroshi

2003-01-01

Quantum walks are expected to provide useful algorithmic tools for quantum computation. This paper introduces absorbing probability and time of quantum walks and gives both numerical simulation results and theoretical analyses on Hadamard walks on the line and symmetric walks on the hypercube from the viewpoint of absorbing probability and time

Random walk through fractal environments

International Nuclear Information System (INIS)

Isliker, H.; Vlahos, L.

2003-01-01

We analyze random walk through fractal environments, embedded in three-dimensional, permeable space. Particles travel freely and are scattered off into random directions when they hit the fractal. The statistical distribution of the flight increments (i.e., of the displacements between two consecutive hittings) is analytically derived from a common, practical definition of fractal dimension, and it turns out to approximate quite well a power-law in the case where the dimension D F of the fractal is less than 2, there is though, always a finite rate of unaffected escape. Random walks through fractal sets with D F ≤2 can thus be considered as defective Levy walks. The distribution of jump increments for D F >2 is decaying exponentially. The diffusive behavior of the random walk is analyzed in the frame of continuous time random walk, which we generalize to include the case of defective distributions of walk increments. It is shown that the particles undergo anomalous, enhanced diffusion for D F F >2 is normal for large times, enhanced though for small and intermediate times. In particular, it follows that fractals generated by a particular class of self-organized criticality models give rise to enhanced diffusion. The analytical results are illustrated by Monte Carlo simulations

Nine walks (photo series / web page)

OpenAIRE

Robinson, Andrew

2015-01-01

'Nine Walks' is a body of work resulting from my engagement with the Media Arts Research Walking Group at Sheffield Hallam University who are exploring the role of walking in as a social, developmental and production space for the creative arts. / My participation in the walking group is an extension of my investigation of the journey as a creative, conceptual and contemplative space for photography which in turn reflects an interest in the role of the accident, instinct and intuition and the...

The Effect of mechanical resistive loading on optimal respiratory signals and breathing patterns under added dead space and CO2 breathing

Directory of Open Access Journals (Sweden)

Lin Shyan-Lung

2016-01-01

Full Text Available Current study aims to investigate how the respiratory resistive loading affects the behaviour of the optimal chemical-mechanical respiratory control model, the respiratory signals and breathing pattern are optimized under external dead space loading and CO2 breathing. The respiratory control was modelled to include a neuro-muscular drive as the control output to derive the waveshapes of instantaneous airflow, lung volume profiles, and breathing pattern, including total/alveolar ventilation, breathing frequency, tidal volume, inspiratory/expiratory duration, duty cycle, and arterial CO2 pressure. The simulations were performed under various respiratory resistive loads, including no load, inspiratory resistive load, expiratory resistive load, and continuous resistive load. The dead space measurement was described with Gray’s derivation, and simulation results were studied and compared with experimental findings.

Demand response to improved walking infrastructure: A study into the economics of walking and health behaviour change.

Science.gov (United States)

Longo, Alberto; Hutchinson, W George; Hunter, Ruth F; Tully, Mark A; Kee, Frank

2015-10-01

Walking is the most common form of moderate-intensity physical activity among adults, is widely accessible and especially appealing to obese people. Most often policy makers are interested in valuing the effect on walking of changes in some characteristics of a neighbourhood, the demand response for walking, of infrastructure changes. A positive demand response to improvements in the walking environment could help meet the public health target of 150 min of at least moderate-intensity physical activity per week. We model walking in an individual's local neighbourhood as a 'weak complement' to the characteristics of the neighbourhood itself. Walking is affected by neighbourhood characteristics, substitutes, and individual's characteristics, including their opportunity cost of time. Using compensating variation, we assess the economic benefits of walking and how walking behaviour is affected by improvements to the neighbourhood. Using a sample of 1209 respondents surveyed over a 12 month period (Feb 2010-Jan 2011) in East Belfast, United Kingdom, we find that a policy that increased walkability and people's perception of access to shops and facilities would lead to an increase in walking of about 36 min/person/week, valued at £13.65/person/week. When focussing on inactive residents, a policy that improved the walkability of the area would lead to guidelines for physical activity being reached by only 12.8% of the population who are currently inactive. Additional interventions would therefore be needed to encourage inactive residents to achieve the recommended levels of physical activity, as it appears that interventions that improve the walkability of an area are particularly effective in increasing walking among already active citizens, and, among the inactive ones, the best response is found among healthier, younger and wealthier citizens. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of independent walking in toddlers

NARCIS (Netherlands)

Ivanenko, Yuri P; Dominici, Nadia; Lacquaniti, Francesco

Surprisingly, despite millions of years of bipedal walking evolution, the gravity-related pendulum mechanism of walking does not seem to be implemented at the onset of independent walking, requiring each toddler to develop it. We discuss the precursor of the mature locomotor pattern in infants as an

Energy cost of walking: solving the paradox of steady state in the presence of variable walking speed.

Science.gov (United States)

Plasschaert, Frank; Jones, Kim; Forward, Malcolm

2009-02-01

Measurement of the energy cost of walking in children with cerebral palsy is used for baseline and outcome assessment. However, such testing relies on the establishment of steady state that is deemed present when oxygen consumption is stable. This is often assumed when walking speed is constant but in practice, speed can and does vary naturally. Whilst constant speed is achievable on a treadmill, this is often impractical clinically, thus rendering an energy cost test to an element of subjectivity. This paper attempts to address this issue by presenting a new method for calculating energy cost of walking that automatically applies a mathematically defined threshold for steady state within a (non-treadmill) walking trial and then strips out all of the non-steady state events within that trial. The method is compared with a generic approach that does not remove non-steady state data but rather uses an average value over a complete walking trial as is often used in the clinical environment. Both methods were applied to the calculation of several energy cost of walking parameters of self-selected walking speed in a cohort of unimpaired subjects and children with cerebral palsy. The results revealed that both methods were strongly correlated for each parameter but showed systematic significant differences. It is suggested that these differences are introduced by the rejection of non-steady state data that would otherwise have incorrectly been incorporated into the calculation of the energy cost of walking indices during self-selected walking with its inherent speed variation.

Breath acetone monitoring by portable Si:WO3 gas sensors

International Nuclear Information System (INIS)

Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

2012-01-01

Highlights: ► Portable sensors were developed and tested for monitoring acetone in the human breath. ► Acetone concentrations down to 20 ppb were measured with short response times ( 3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (∼20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques.

Remote monitoring of breathing dynamics using infrared thermography.

Science.gov (United States)

Pereira, Carina Barbosa; Yu, Xinchi; Czaplik, Michael; Rossaint, Rolf; Blazek, Vladimir; Leonhardt, Steffen

2015-11-01

An atypical or irregular respiratory frequency is considered to be one of the earliest markers of physiological distress. In addition, monitoring of this vital parameter plays a major role in diagnosis of respiratory disorders, as well as in early detection of sudden infant death syndrome. Nevertheless, the current measurement modalities require attachment of sensors to the patient's body, leading to discomfort and stress. The current paper presents a new robust algorithm to remotely monitor breathing rate (BR) by using thermal imaging. This approach permits to detect and to track the region of interest (nose) as well as to estimate BR. In order to study the performance of the algorithm, and its robustness against motion and breathing disorders, three different thermal recordings of 11 healthy volunteers were acquired (sequence 1: normal breathing; sequence 2: normal breathing plus arbitrary head movements; and sequence 3: sequence of specific breathing patterns). Thoracic effort (piezoplethysmography) served as "gold standard" for validation of our results. An excellent agreement between estimated BR and ground truth was achieved. Whereas the mean correlation for sequence 1-3 were 0.968, 0.940 and 0.974, the mean absolute BR errors reached 0.33, 0.55 and 0.96 bpm (breaths per minute), respectively. In brief, this work demonstrates that infrared thermography is a promising, clinically relevant alternative for the currently available measuring modalities due to its performance and diverse remarkable advantages.

Intra-fraction motion of the prostate is a random walk

Science.gov (United States)

Ballhausen, H.; Li, M.; Hegemann, N.-S.; Ganswindt, U.; Belka, C.

2015-01-01

A random walk model for intra-fraction motion has been proposed, where at each step the prostate moves a small amount from its current position in a random direction. Online tracking data from perineal ultrasound is used to validate or reject this model against alternatives. Intra-fraction motion of a prostate was recorded by 4D ultrasound (Elekta Clarity system) during 84 fractions of external beam radiotherapy of six patients. In total, the center of the prostate was tracked for 8 h in intervals of 4 s. Maximum likelihood model parameters were fitted to the data. The null hypothesis of a random walk was tested with the Dickey-Fuller test. The null hypothesis of stationarity was tested by the Kwiatkowski-Phillips-Schmidt-Shin test. The increase of variance in prostate position over time and the variability in motility between fractions were analyzed. Intra-fraction motion of the prostate was best described as a stochastic process with an auto-correlation coefficient of ρ = 0.92  ±  0.13. The random walk hypothesis (ρ = 1) could not be rejected (p = 0.27). The static noise hypothesis (ρ = 0) was rejected (p test rejected the null hypothesis ρ = 1 in 25% to 32% of cases. On average, the Kwiatkowski-Phillips-Schmidt-Shin test rejected the null hypothesis ρ = 0 with a probability of 93% to 96%. The variance in prostate position increased linearly over time (r2 = 0.9  ±  0.1). Variance kept increasing and did not settle at a maximum as would be expected from a stationary process. There was substantial variability in motility between fractions and patients with maximum aberrations from isocenter ranging from 0.5 mm to over 10 mm in one patient alone. In conclusion, evidence strongly suggests that intra-fraction motion of the prostate is a random walk and neither static (like inter-fraction setup errors) nor stationary (like a cyclic motion such as breathing, for example). The prostate tends to drift away from the isocenter during a fraction, and

Intra-fraction motion of the prostate is a random walk

International Nuclear Information System (INIS)

Ballhausen, H; Li, M; Hegemann, N-S; Ganswindt, U; Belka, C

2015-01-01

A random walk model for intra-fraction motion has been proposed, where at each step the prostate moves a small amount from its current position in a random direction. Online tracking data from perineal ultrasound is used to validate or reject this model against alternatives. Intra-fraction motion of a prostate was recorded by 4D ultrasound (Elekta Clarity system) during 84 fractions of external beam radiotherapy of six patients. In total, the center of the prostate was tracked for 8 h in intervals of 4 s. Maximum likelihood model parameters were fitted to the data. The null hypothesis of a random walk was tested with the Dickey–Fuller test. The null hypothesis of stationarity was tested by the Kwiatkowski–Phillips–Schmidt–Shin test. The increase of variance in prostate position over time and the variability in motility between fractions were analyzed. Intra-fraction motion of the prostate was best described as a stochastic process with an auto-correlation coefficient of ρ = 0.92  ±  0.13. The random walk hypothesis (ρ = 1) could not be rejected (p = 0.27). The static noise hypothesis (ρ = 0) was rejected (p < 0.001). The Dickey–Fuller test rejected the null hypothesis ρ = 1 in 25% to 32% of cases. On average, the Kwiatkowski–Phillips–Schmidt–Shin test rejected the null hypothesis ρ = 0 with a probability of 93% to 96%. The variance in prostate position increased linearly over time (r 2 = 0.9  ±  0.1). Variance kept increasing and did not settle at a maximum as would be expected from a stationary process. There was substantial variability in motility between fractions and patients with maximum aberrations from isocenter ranging from 0.5 mm to over 10 mm in one patient alone. In conclusion, evidence strongly suggests that intra-fraction motion of the prostate is a random walk and neither static (like inter-fraction setup errors) nor stationary (like a cyclic motion such as breathing, for example). The prostate tends to

To Walk or Not to Walk?: The Hierarchy of Walking Needs

Science.gov (United States)

Alfonzo, Mariela

2005-01-01

The multitude of quality of life problems associated with declining walking rates has impelled researchers from various disciplines to identify factors related to this behavior change. Currently, this body of research is in need of a transdisciplinary, multilevel theoretical model that can help explain how individual, group, regional, and…

A simple, remote, video based breathing monitor.

Science.gov (United States)

Regev, Nir; Wulich, Dov

2017-07-01

Breathing monitors have become the all-important cornerstone of a wide variety of commercial and personal safety applications, ranging from elderly care to baby monitoring. Many such monitors exist in the market, some, with vital signs monitoring capabilities, but none remote. This paper presents a simple, yet efficient, real time method of extracting the subject's breathing sinus rhythm. Points of interest are detected on the subject's body, and the corresponding optical flow is estimated and tracked using the well known Lucas-Kanade algorithm on a frame by frame basis. A generalized likelihood ratio test is then utilized on each of the many interest points to detect which is moving in harmonic fashion. Finally, a spectral estimation algorithm based on Pisarenko harmonic decomposition tracks the harmonic frequency in real time, and a fusion maximum likelihood algorithm optimally estimates the breathing rate using all points considered. The results show a maximal error of 1 BPM between the true breathing rate and the algorithm's calculated rate, based on experiments on two babies and three adults.

Sex differences in sleep disordered breathing in adults.

Science.gov (United States)

Lozo, Tijana; Komnenov, Dragana; Badr, M Safwan; Mateika, Jason H

2017-11-01

The prevalence of sleep disordered breathing is greater in men compared to women. This disparity could be due to sex differences in the diagnosis and presentation of sleep apnea, and the pathophysiological mechanisms that instigate this disorder. Women tend to report more non-typical symptoms of sleep apnea compared to men, and the presentation of apneic events are more prevalent in rapid compared to non-rapid eye movement sleep. In addition, there is evidence of sex differences in upper airway structure and mechanics and in neural mechanisms that impact on the control of breathing. The purpose of this review is to summarize the literature that addresses sex differences in sleep-disordered breathing, and to discuss the influence that upper airway mechanics, chemoreflex properties, and sex hormones have in modulating breathing during sleep in men and women. Published by Elsevier B.V.

Walks on SPR neighborhoods.

Science.gov (United States)

Caceres, Alan Joseph J; Castillo, Juan; Lee, Jinnie; St John, Katherine

2013-01-01

A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, T1, T2, . . . , T(k) where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNI-walks that visit all trees in a subtree-prune-and-regraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, T, on n leaves, the shortest walk takes Θ(n²) additional steps more than the number of trees in the SPR neighborhood. This answers Bryant’s Second Combinatorial Challenge from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and the Penny Ante Problem List, 2009.

Awareness of breathing: the structure of language descriptors of respiratory sensations.

Science.gov (United States)

Petersen, Sibylle; Orth, Bernhard; Ritz, Thomas

2008-01-01

Recent research suggests that dyspnea is not a single sensation but a multidimensional construct reflected in different verbal descriptors that can provide useful diagnostic information. In this study superordinated clusters of dyspnea were investigated in combination with a dimensional approach. We examined the use of 20 respiratory symptom descriptors by healthy volunteers who completed a protocol of seven experimental conditions: Quiet breathing, breath holding, paced breathing, climbing stairs, resistive load breathing, voluntary hyperinflation, and voluntary hyperventilation. We analyzed the ratings of these descriptors with multidimensional scaling (MDS) and cluster analysis. While similarities with prior studies were found on a lower fusion level, we were able to demonstrate the usefulness of interpreting higher fusion levels with four clusters related to work of breathing, coordination, suffocation, and struggling for air, merging into two superordinated clusters, effort and air hunger that are compatible with widely accepted primary components of dyspnea. MDS results also suggested that future studies should consider further breathing sensations related to cognitive control of breathing.

Analysis of human exhaled breath in a population of young volunteers

Directory of Open Access Journals (Sweden)

Zarić Božidarka

2014-01-01

Full Text Available Analysis of volatile organic compounds (VOCs in human breath can provide information about the current physiological state of an individual, such as clinical conditions and exposure to exogenous pollutants. The blood-borne VOCs present in exhaled breath offer the possibility of exploring physiological and pathological processes in a noninvasive way. However, the field of exhaled breath analysis is still in its infancy. We undertook this study in order to define interindividual variation and common compounds in breath VOCs of 48 young human volunteers. Alveolar breath samples were analyzed by automated thermal desorption, gas chromatography with flame ionization detector (FID and electron capture detector (ECD using SUPELCO standards with 66 compounds. Predominant compounds in the alveolar breath of analyzed subjects are ethylbenzene, 1-ethyl-4-methylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene (over 50% of the subjects. Isopropyl alcohol, propylene, acetone, ethanol were found as well. We detected substituted compounds in exhaled breath. [Projekat Ministarstva nauke Republike Srbije, br. 172001

Breathing multichimera states in nonlocally coupled phase oscillators

Science.gov (United States)

Suda, Yusuke; Okuda, Koji

2018-04-01

Chimera states for the one-dimensional array of nonlocally coupled phase oscillators in the continuum limit are assumed to be stationary states in most studies, but a few studies report the existence of breathing chimera states. We focus on multichimera states with two coherent and incoherent regions and numerically demonstrate that breathing multichimera states, whose global order parameter oscillates temporally, can appear. Moreover, we show that the system exhibits a Hopf bifurcation from a stationary multichimera to a breathing one by the linear stability analysis for the stationary multichimera.

James Watt's Leicester Walk

OpenAIRE

Bell, Kathleen

2016-01-01

a poem in which James Watt, inventor of the separate condenser, walks through contemporary Leicester (his route is from Bonners Lane and alongside the canal, taking in the Statue of Liberty on its traffic island near Sage Road). It is derived from the exercise of taking a character for a walk,

Effect of Body Composition on Walking Economy

Directory of Open Access Journals (Sweden)

Maciejczyk Marcin

2016-12-01

Full Text Available Purpose. The aim of the study was to evaluate walking economy and physiological responses at two walking speeds in males with similar absolute body mass but different body composition. Methods. The study involved 22 young men with similar absolute body mass, BMI, aerobic performance, calf and thigh circumference. The participants differed in body composition: body fat (HBF group and lean body mass (HLBM group. In the graded test, maximal oxygen uptake (VO2max and maximal heart rate were measured. Walking economy was evaluated during two walks performed at two different speeds (4.8 and 6.0 km ‧ h-1. Results. The VO2max was similar in both groups, as were the physiological responses during slow walking. The absolute oxygen uptake or oxygen uptake relative to body mass did not significantly differentiate the studied groups. The only indicator significantly differentiating the two groups was oxygen uptake relative to LBM. Conclusions. Body composition does not significantly affect walking economy at low speed, while during brisk walking, the economy is better in the HLBM vs. HBF group, provided that walking economy is presented as oxygen uptake relative to LBM. For this reason, we recommend this manner of oxygen uptake normalization in the evaluation of walking economy.

Relationship between quantum walks and relativistic quantum mechanics

International Nuclear Information System (INIS)

Chandrashekar, C. M.; Banerjee, Subhashish; Srikanth, R.

2010-01-01

Quantum walk models have been used as an algorithmic tool for quantum computation and to describe various physical processes. This article revisits the relationship between relativistic quantum mechanics and the quantum walks. We show the similarities of the mathematical structure of the decoupled and coupled forms of the discrete-time quantum walk to that of the Klein-Gordon and Dirac equations, respectively. In the latter case, the coin emerges as an analog of the spinor degree of freedom. Discrete-time quantum walk as a coupled form of the continuous-time quantum walk is also shown by transforming the decoupled form of the discrete-time quantum walk to the Schroedinger form. By showing the coin to be a means to make the walk reversible and that the Dirac-like structure is a consequence of the coin use, our work suggests that the relativistic causal structure is a consequence of conservation of information. However, decoherence (modeled by projective measurements on position space) generates entropy that increases with time, making the walk irreversible and thereby producing an arrow of time. The Lieb-Robinson bound is used to highlight the causal structure of the quantum walk to put in perspective the relativistic structure of the quantum walk, the maximum speed of walk propagation, and earlier findings related to the finite spread of the walk probability distribution. We also present a two-dimensional quantum walk model on a two-state system to which the study can be extended.

Quantum Walks on the Line with Phase Parameters

Science.gov (United States)

Villagra, Marcos; Nakanishi, Masaki; Yamashita, Shigeru; Nakashima, Yasuhiko

In this paper, a study on discrete-time coined quantum walks on the line is presented. Clear mathematical foundations are still lacking for this quantum walk model. As a step toward this objective, the following question is being addressed: Given a graph, what is the probability that a quantum walk arrives at a given vertex after some number of steps? This is a very natural question, and for random walks it can be answered by several different combinatorial arguments. For quantum walks this is a highly non-trivial task. Furthermore, this was only achieved before for one specific coin operator (Hadamard operator) for walks on the line. Even considering only walks on lines, generalizing these computations to a general SU(2) coin operator is a complex task. The main contribution is a closed-form formula for the amplitudes of the state of the walk (which includes the question above) for a general symmetric SU(2) operator for walks on the line. To this end, a coin operator with parameters that alters the phase of the state of the walk is defined. Then, closed-form solutions are computed by means of Fourier analysis and asymptotic approximation methods. We also present some basic properties of the walk which can be deducted using weak convergence theorems for quantum walks. In particular, the support of the induced probability distribution of the walk is calculated. Then, it is shown how changing the parameters in the coin operator affects the resulting probability distribution.

Spike-Timing of Orbitofrontal Neurons Is Synchronized With Breathing.

Science.gov (United States)

Kőszeghy, Áron; Lasztóczi, Bálint; Forro, Thomas; Klausberger, Thomas

2018-01-01

The orbitofrontal cortex (OFC) has been implicated in a multiplicity of complex brain functions, including representations of expected outcome properties, post-decision confidence, momentary food-reward values, complex flavors and odors. As breathing rhythm has an influence on odor processing at primary olfactory areas, we tested the hypothesis that it may also influence neuronal activity in the OFC, a prefrontal area involved also in higher order processing of odors. We recorded spike timing of orbitofrontal neurons as well as local field potentials (LFPs) in awake, head-fixed mice, together with the breathing rhythm. We observed that a large majority of orbitofrontal neurons showed robust phase-coupling to breathing during immobility and running. The phase coupling of action potentials to breathing was significantly stronger in orbitofrontal neurons compared to cells in the medial prefrontal cortex. The characteristic synchronization of orbitofrontal neurons with breathing might provide a temporal framework for multi-variable processing of olfactory, gustatory and reward-value relationships.

Spike-Timing of Orbitofrontal Neurons Is Synchronized With Breathing

Directory of Open Access Journals (Sweden)

Áron Kőszeghy

2018-04-01

Full Text Available The orbitofrontal cortex (OFC has been implicated in a multiplicity of complex brain functions, including representations of expected outcome properties, post-decision confidence, momentary food-reward values, complex flavors and odors. As breathing rhythm has an influence on odor processing at primary olfactory areas, we tested the hypothesis that it may also influence neuronal activity in the OFC, a prefrontal area involved also in higher order processing of odors. We recorded spike timing of orbitofrontal neurons as well as local field potentials (LFPs in awake, head-fixed mice, together with the breathing rhythm. We observed that a large majority of orbitofrontal neurons showed robust phase-coupling to breathing during immobility and running. The phase coupling of action potentials to breathing was significantly stronger in orbitofrontal neurons compared to cells in the medial prefrontal cortex. The characteristic synchronization of orbitofrontal neurons with breathing might provide a temporal framework for multi-variable processing of olfactory, gustatory and reward-value relationships.

Cognitive Resource Demands of Redirected Walking.

Science.gov (United States)

Bruder, Gerd; Lubas, Paul; Steinicke, Frank

2015-04-01

Redirected walking allows users to walk through a large-scale immersive virtual environment (IVE) while physically remaining in a reasonably small workspace. Therefore, manipulations are applied to virtual camera motions so that the user's self-motion in the virtual world differs from movements in the real world. Previous work found that the human perceptual system tolerates a certain amount of inconsistency between proprioceptive, vestibular and visual sensation in IVEs, and even compensates for slight discrepancies with recalibrated motor commands. Experiments showed that users are not able to detect an inconsistency if their physical path is bent with a radius of at least 22 meters during virtual straightforward movements. If redirected walking is applied in a smaller workspace, manipulations become noticeable, but users are still able to move through a potentially infinitely large virtual world by walking. For this semi-natural form of locomotion, the question arises if such manipulations impose cognitive demands on the user, which may compete with other tasks in IVEs for finite cognitive resources. In this article we present an experiment in which we analyze the mutual influence between redirected walking and verbal as well as spatial working memory tasks using a dual-tasking method. The results show an influence of redirected walking on verbal as well as spatial working memory tasks, and we also found an effect of cognitive tasks on walking behavior. We discuss the implications and provide guidelines for using redirected walking in virtual reality laboratories.

Positive messaging promotes walking in older adults.

Science.gov (United States)

Notthoff, Nanna; Carstensen, Laura L

2014-06-01

Walking is among the most cost-effective and accessible means of exercise. Mounting evidence suggests that walking may help to maintain physical and cognitive independence in old age by preventing a variety of health problems. However, older Americans fall far short of meeting the daily recommendations for walking. In 2 studies, we examined whether considering older adults' preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, we compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, we examined within-person change in walking in older adults in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages, and the effect was sustained across the intervention period. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles. Future research is needed to examine the mechanisms underlying the greater effectiveness of positively- as opposed to negatively-framed messages and the generalizability of findings to other intervention targets and other subpopulations of older adults. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Treadmill walking of the pneumatic biped Lucy: Walking at different speeds and step-lengths

Science.gov (United States)

Vanderborght, B.; Verrelst, B.; Van Ham, R.; Van Damme, M.; Versluys, R.; Lefeber, D.

2008-07-01

Actuators with adaptable compliance are gaining interest in the field of legged robotics due to their capability to store motion energy and to exploit the natural dynamics of the system to reduce energy consumption while walking and running. To perform research on compliant actuators we have built the planar biped Lucy. The robot has six actuated joints, the ankle, knee and hip of both legs with each joint powered by two pleated pneumatic artificial muscles in an antagonistic setup. This makes it possible to control both the torque and the stiffness of the joint. Such compliant actuators are used in passive walkers to overcome friction when walking over level ground and to improve stability. Typically, this kind of robots is only designed to walk with a constant walking speed and step-length, determined by the mechanical design of the mechanism and the properties of the ground. In this paper, we show that by an appropriate control, the robot Lucy is able to walk at different speeds and step-lengths and that adding and releasing weights does not affect the stability of the robot. To perform these experiments, an automated treadmill was built

Can resistive breathing injure the lung? Implications for COPD exacerbations

Directory of Open Access Journals (Sweden)

Vassilakopoulos T

2016-09-01

Full Text Available Theodoros Vassilakopoulos, Dimitrios Toumpanakis Pulmonary and Critical Care Medicine, Medical School, National and Kapodistrian University of Athens, Greece Abstract: In obstructive lung diseases, airway inflammation leads to bronchospasm and thus resistive breathing, especially during exacerbations. This commentary discusses experimental evidence that resistive breathing per se (the mechanical stimulus in the absence of underlying airway inflammation leads to lung injury and inflammation (mechanotransduction. The potential implications of resistive breathing-induced mechanotrasduction in COPD exacerbations are presented along with the available clinical evidence. Keywords: resistive breathing, COPD, mechanotransduction, bronchoconstriction, inflammation

Can audio coached 4D CT emulate free breathing during the treatment course?

DEFF Research Database (Denmark)

Persson, Gitte F; Nygaard, Ditte E; Olsen, Mikael

2008-01-01

BACKGROUND: The image quality of 4DCT depends on breathing regularity. Respiratory audio coaching may improve regularity and reduce motion artefacts. We question the safety of coached planning 4DCT without coaching during treatment. We investigated the possibility of coaching to a more stable...... breathing without changing the breathing amplitude. The interfraction variation of the breathing cycle amplitude in free and coached breathing was studied as well as the possible impact of fatigue on longer coaching sessions. METHODS: Thirteen volunteers completed respiratory audio coaching on 3 days within...... a 2 week period. An external marker system monitoring the motion of the thoraco-abdominal wall was used to track the respiration. On all days, free breathing and two coached breathing curves were recorded. We assumed that free versus coached breathing from day 1 (reference session) simulated breathing...

Full revivals in 2D quantum walks

International Nuclear Information System (INIS)

Stefanak, M; Jex, I; Kollar, B; Kiss, T

2010-01-01

Recurrence of a random walk is described by the Polya number. For quantum walks, recurrence is understood as the return of the walker to the origin, rather than the full revival of its quantum state. Localization for two-dimensional quantum walks is known to exist in the sense of non-vanishing probability distribution in the asymptotic limit. We show, on the example of the 2D Grover walk, that one can exploit the effect of localization to construct stationary solutions. Moreover, we find full revivals of a quantum state with a period of two steps. We prove that there cannot be longer cycles for a four-state quantum walk. Stationary states and revivals result from interference, which has no counterpart in classical random walks.

Improved ROS defense in the swimbladder of a facultative air-breathing erythrinid fish, jeju, compared to a non-air-breathing close relative, traira.

Science.gov (United States)

Pelster, Bernd; Giacomin, Marina; Wood, Chris M; Val, Adalberto L

2016-07-01

The jeju Hoplerythrinus unitaeniatus and the traira Hoplias malabaricus are two closely related erythrinid fish, both possessing a two-chambered physostomous swimbladder. In the jeju the anterior section of the posterior bladder is highly vascularized and the swimbladder is used for aerial respiration; the traira, in turn, is a water-breather that uses the swimbladder as a buoyancy organ and not for aerial oxygen uptake. Observation of the breathing behavior under different levels of water oxygenation revealed that the traira started aquatic surface respiration only under severe hypoxic conditions and did not breathe air. In the jeju air-breathing behavior was observed under normoxic conditions, and the frequency of air-breathing was significantly increased under hypoxic conditions. Unexpectedly, even under hyperoxic conditions (30 mg O2 L(-1)) the jeju continued to take air breaths, and compared with normoxic conditions the frequency was not reduced. Because the frequently air-exposed swimbladder tissue faces higher oxygen partial pressures than normally experienced by other fish tissues, it was hypothesized that in the facultative air-breathing jeju, swimbladder tissue would have a higher antioxidative capacity than the swimbladder tissue of the water breathing traira. Measurement of total glutathione (GSSG/GSH) concentration in anterior and posterior swimbladder tissue revealed a higher concentration of this antioxidant in swimbladder tissue as compared to muscle tissue in the jeju. Furthermore, the GSSG/GSH concentration in jeju tissues was significantly higher than in traira tissues. Similarly, activities of enzymes involved in the breakdown of reactive oxygen species were significantly higher in the jeju swimbladder as compared to the traira swimbladder. The results show that the jeju, using the swimbladder as an additional breathing organ, has an enhanced antioxidative capacity in the swimbladder as compared to the traira, using the swimbladder only as a

Optimization of imaging before pulmonary vein isolation by radiofrequency ablation: breath-held ungated versus ECG/breath-gated MRA

Energy Technology Data Exchange (ETDEWEB)

Allgayer, C.; Haller, S.; Bremerich, J. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Zellweger, M.J.; Sticherling, C.; Buser, P.T. [University Hospital Basel, Department of Cardiology, Basel (Switzerland); Weber, O. [University Hospital Basel, Department of Medical Physics, Basel (Switzerland)

2008-12-15

Isolation of the pulmonary veins has emerged as a new therapy for atrial fibrillation. Pre-procedural magnetic resonance (MR) imaging enhances safety and efficacy; moreover, it reduces radiation exposure of the patients and interventional team. The purpose of this study was to optimize the MR protocol with respect to image quality and acquisition time. In 31 patients (23-73 years), the anatomy of the pulmonary veins, left atrium and oesophagus was assessed on a 1.5-Tesla scanner with four different sequences: (1) ungated two-dimensional true fast imaging with steady precession (2D-TrueFISP), (2) ECG/breath-gated 3D-TrueFISP, (3) ungated breath-held contrast-enhanced three-dimensional turbo fast low-angle shot (CE-3D-tFLASH), and (4) ECG/breath-gated CE-3D-TrueFISP. Image quality was scored from 1 (structure not visible) to 5 (excellent visibility), and the acquisition time was monitored. The pulmonary veins and left atrium were best visualized with CE-3D-tFLASH (scores 4.50 {+-} 0.52 and 4.59 {+-} 0.43) and ECG/breath-gated CE-3D-TrueFISP (4.47 {+-} 0.49 and 4.63 {+-} 0.39). Conspicuity of the oesophagus was optimal with CE-3D-TrueFISP and 2D-TrueFISP (4.59 {+-} 0.35 and 4.19 {+-} 0.46) but poor with CE-3D-tFLASH (1.03 {+-} 0.13) (p < 0.05). Acquisition times were shorter for 2D-TrueFISP (44 {+-} 1 s) and CE-3D-tFLASH (345 {+-} 113 s) compared with ECG/breath-gated 3D-TrueFISP (634 {+-} 197 s) and ECG/breath-gated CE-3D-TrueFISP (636 {+-} 230 s) (p < 0.05). In conclusion, an MR imaging protocol comprising CE-3D-tFLASH and 2D-TrueFISP allows assessment of the pulmonary veins, left atrium and oesophagus in less than 7 min and can be recommended for pre-procedural imaging before electric isolation of pulmonary veins. (orig.)

15 things you need to know about healthy eating.

Science.gov (United States)

Chavez, C

1995-01-01

Good nutrition is essential to good health during all phases of living with HIV. Good nutrition helps the body fight infections, enables HIV-fighting drugs to work properly, and in some cases may ease drug-related side effects. The author suggests fifteen things people should know to get the most out of their daily diet. These include: eat foods from the five basic food groups; increase calorie intake; eat a combination of foods rich in protein, carbohydrates, and moderate amounts of fat; consume small frequent meals; avoid junk foods; drink plenty of liquids; maintain usual body weight; take a multi-vitamin and mineral supplement, but beware of megadosing; take charge when dining out; have regular dental checkups; establish a regular exercise program; and consult a registered dietitian specializing in HIV. Weight loss is of special concern for those living with HIV. The author suggests taking a short walk before eating and exploring the variety of nutritional supplements to increase calorie intake.

Breath acetone monitoring by portable Si:WO3 gas sensors

Science.gov (United States)

Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

2013-01-01

Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical diagnostic costs and improve the quality of life of patients suffering from chronic illnesses. In particular, the detection of acetone in the human breath is promising for non-invasive diagnosis and painless monitoring of diabetes (no finger pricking). Here, a portable acetone sensor consisting of flame-deposited and in situ annealed, Si-doped epsilon-WO3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (~20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques. PMID:22790702

Exploring topological phases with quantum walks

International Nuclear Information System (INIS)

Kitagawa, Takuya; Rudner, Mark S.; Berg, Erez; Demler, Eugene

2010-01-01

The quantum walk was originally proposed as a quantum-mechanical analog of the classical random walk, and has since become a powerful tool in quantum information science. In this paper, we show that discrete-time quantum walks provide a versatile platform for studying topological phases, which are currently the subject of intense theoretical and experimental investigations. In particular, we demonstrate that recent experimental realizations of quantum walks with cold atoms, photons, and ions simulate a nontrivial one-dimensional topological phase. With simple modifications, the quantum walk can be engineered to realize all of the topological phases, which have been classified in one and two dimensions. We further discuss the existence of robust edge modes at phase boundaries, which provide experimental signatures for the nontrivial topological character of the system.

Walking in Place Through Virtual Worlds

DEFF Research Database (Denmark)

Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

2016-01-01

Immersive virtual reality (IVR) is seemingly on the verge of entering the homes of consumers. Enabling users to walk through virtual worlds in a limited physical space presents a challenge. With an outset in a taxonomy of virtual travel techniques, we argue that Walking-in-Place (WIP) techniques...... constitute a promising approach to virtual walking in relation to consumer IVR. Subsequently we review existing approaches to WIP locomotion and highlight the need for a more explicit focus on the perceived naturalness of WIP techniques; i.e., the degree to which WIP locomotion feels like real walking....... Finally, we summarize work we have performed in order to produce more natural WIP locomotion and present unexplored topics which need to be address if WIP techniques are to provide perceptually natural walking experiences....

Self-Trapping Self-Repelling Random Walks

Science.gov (United States)

Grassberger, Peter

2017-10-01

Although the title seems self-contradictory, it does not contain a misprint. The model we study is a seemingly minor modification of the "true self-avoiding walk" model of Amit, Parisi, and Peliti in two dimensions. The walks in it are self-repelling up to a characteristic time T* (which depends on various parameters), but spontaneously (i.e., without changing any control parameter) become self-trapping after that. For free walks, T* is astronomically large, but on finite lattices the transition is easily observable. In the self-trapped regime, walks are subdiffusive and intermittent, spending longer and longer times in small areas until they escape and move rapidly to a new area. In spite of this, these walks are extremely efficient in covering finite lattices, as measured by average cover times.

Breath-by-breath analysis of expiratory gas concentration in chickens.

Science.gov (United States)

Itabisashi, T

1981-01-01

Expiratory oxygen and carbon-dioxide concentration were analysed breath by breath in order to examine their wave forms in adult awake hens restrained in various postural positions, including supine, prone and sitting positions. Expired gas was collected at the nostril in almost all the hens. In the sitting position free from vocalization, feeding, drinking, panting, and restlessness, hens showed various forms of stable pattern of oxygen-gas curves. These forms were classified into three types, or the ascending, flat and descending types, with respect to the plateau inclination. The waves of carbon-dioxide were not always a mirror image of those of oxygen. The rate of occurrence of each type varied with the hen's postural position. The wave form was altered with the experimental body-rotation of the hen. When placed between the deflections of stable pattern, the episodes of wave deformation resembling that seen at the time of uneven pulmonary ventilation in mammals could frequently be observed in any hen's posture examined. Cardiogenic oscillation appeared on the plateau of expired-gas curves.

Walking dreams in congenital and acquired paraplegia.

Science.gov (United States)

Saurat, Marie-Thérèse; Agbakou, Maité; Attigui, Patricia; Golmard, Jean-Louis; Arnulf, Isabelle

2011-12-01

To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4-64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep. Copyright © 2011 Elsevier Inc. All rights reserved.

Inspirometria de incentivo e breath stacking: repercussões sobre a capacidade inspiratória em indivíduos submetidos à cirurgia abdominal Incentive spirometry and breath stacking: effects on the inspiratory capacity of individuals submitted to abdominal surgery

Directory of Open Access Journals (Sweden)

CM Dias

2008-04-01

it is necessary to know which therapeutic approaches are the best ones to implement. OBJECTIVE: To compare the inspiratory volume during the breath stacking maneuver with the volume during incentive spirometry, in abdominal surgery patients. METHODS: Twelve patients, on their first postoperative day, were instructed to take a deep breath through the VoldyneTM incentive spirometer and to make successive inspiratory efforts using a facemask that had been adapted for performing the breath stacking maneuver. Each technique was performed five times according to the randomization. Before the operation, the patients performed a spirometric test. They were also assessed and instructed about the procedures. A WrightTM ventilometer allowed inspiratory capacity to be recorded. RESULTS: The inspiratory capacity during breath stacking was significantly higher than during incentive spirometry, both before and after the operation. There was a significant reduction in volumes after the surgical procedure, independent of the technique performed. CONCLUSIONS: The breath stacking technique was shown to be effective. This technique was better than incentive spirometry for generating and sustaining inspiratory volumes. Since no adverse effects have been described, this technique can probably be used safely and effectively, particularly in uncooperative patients.

Quantum snake walk on graphs

International Nuclear Information System (INIS)

Rosmanis, Ansis

2011-01-01

I introduce a continuous-time quantum walk on graphs called the quantum snake walk, the basis states of which are fixed-length paths (snakes) in the underlying graph. First, I analyze the quantum snake walk on the line, and I show that, even though most states stay localized throughout the evolution, there are specific states that most likely move on the line as wave packets with momentum inversely proportional to the length of the snake. Next, I discuss how an algorithm based on the quantum snake walk might potentially be able to solve an extended version of the glued trees problem, which asks to find a path connecting both roots of the glued trees graph. To the best of my knowledge, no efficient quantum algorithm solving this problem is known yet.

Breath acetone concentration; biological variability and the influence of diet

International Nuclear Information System (INIS)

Španěl, Patrik; Dryahina, Kseniya; Rejšková, Alžběta; Chippendale, Thomas W E; Smith, David

2011-01-01

Previous measurements of acetone concentrations in the exhaled breath of healthy individuals and the small amount of comparable data for individuals suffering from diabetes are briefly reviewed as a prelude to the presentation of new data on the sporadic and wide variations of breath acetone that occur in ostensibly healthy individuals. Data are also presented which show that following a ketogenic diet taken by eight healthy individuals their breath acetone concentrations increased up to five times over the subsequent 6 h. Similarly, the breath acetone increased six and nine times when a low carbohydrate diet was taken by two volunteers and remained high for the several days for which the diet was continued. These new data, together with the previous data, clearly indicate that diet and natural intra-individual biological and diurnal variability result in wide variations in breath acetone concentration. This places an uncertainty in the use of breath acetone alone to monitor blood glucose and glycaemic control, except and unless the individual acts as their own control and is cognizant of the need for dietary control. (note)

Fast-starting for a breath: Air breathing in Hoplosternum littorale

DEFF Research Database (Denmark)

Domenici, Paolo; Norin, Tommy; Bushnell, Peter G.

by the fall of a prey item on the water surface, and in tapping motions of goldfish, a behaviour that was interpreted to be food-related. Little is known about C-starts being used outside the context of escaping or feeding. Here, we test the hypothesis that air-breathing fish may use C-starts when gulping air...

Know How to Use Your Asthma Inhaler

Medline Plus

Full Text Available ... CDC Publications on Asthma National Asthma Control Program America Breathing Easier Guide for State Programs Interventions Community ... over their asthma. Quick Links Asthma Action Plan America Breathing Easier [PDF – 1.1 MB] ASL Asthma ...

More Adults Are Walking

Centers for Disease Control (CDC) Podcasts

2012-07-31

This podcast is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.  Created: 7/31/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/7/2012.

Mapleson′s breathing systems

Directory of Open Access Journals (Sweden)

Tej K Kaul

2013-01-01

Full Text Available Mapleson breathing systems are used for delivering oxygen and anaesthetic agents and to eliminate carbon dioxide during anaesthesia. They consist of different components: Fresh gas flow, reservoir bag, breathing tubes, expiratory valve, and patient connection. There are five basic types of Mapleson system: A, B, C, D and E depending upon the different arrangements of these components. Mapleson F was added later. For adults, Mapleson A is the circuit of choice for spontaneous respiration where as Mapleson D and its Bains modifications are best available circuits for controlled ventilation. For neonates and paediatric patients Mapleson E and F (Jackson Rees modification are the best circuits. In this review article, we will discuss the structure of the circuits and functional analysis of various types of Mapleson systems and their advantages and disadvantages.

Minnesota Walk-In Access Sites

Data.gov (United States)

Minnesota Department of Natural Resources — The Minnesota Walk-In Access site (WIA) GIS data represents areas of private land that have been made open to the public for the purpose of walk-in (foot travel)...

IMPLICATIONS OF MOUTH BREATHING AND ATYPICAL SWALLOWING IN BODY POSTURE

Directory of Open Access Journals (Sweden)

Veronique Sousa

2017-07-01

Conclusion: Statistically significant associations were established between the breathing pattern and the horizontal alignment of acromions, as well as the horizontal and vertical alignment of the head; between the pattern of breathing and swallowing with occlusal relationship anteroposterior and occlusal relationship vertical and also between breathing pattern and swallowing with digital sucking habits and pacifier use.

Breath Hydrogen Produced by Ingestion of Commercial Hydrogen Water and Milk

OpenAIRE

Shimouchi, Akito; Nose, Kazutoshi; Yamaguchi, Makoto; Ishiguro, Hiroshi; Kondo, Takaharu

2009-01-01

Objective: To compare how and to what extent ingestion of hydrogen water and milk increase breath hydrogen in adults.Methods: Five subjects without specific diseases, ingested distilled or hydrogen water and milk as a reference material that could increase breath hydrogen. Their end-alveolar breath hydrogen was measured.Results: Ingestion of hydrogen water rapidly increased breath hydrogen to the maximal level of approximately 40 ppm 10–15 min after ingestion and thereafter rapidly decrease...

Running and Breathing in Mammals

Science.gov (United States)

Bramble, Dennis M.; Carrier, David R.

1983-01-01

Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.

Let's Walk Outdoors! Self-Paced Walking Outdoors Improves Future Intention to Exercise in Women With Obesity.

Science.gov (United States)

Krinski, Kleverton; Machado, Daniel G S; Lirani, Luciana S; DaSilva, Sergio G; Costa, Eduardo C; Hardcastle, Sarah J; Elsangedy, Hassan M

2017-04-01

In order to examine whether environmental settings influence psychological and physiological responses of women with obesity during self-paced walking, 38 women performed two exercise sessions (treadmill and outdoors) for 30 min, where oxygen uptake, heart rate, ratings of perceived exertion, affect, attentional focus, enjoyment, and future intentions to walk were analyzed. Physiological responses were similar during both sessions. However, during outdoor exercise, participants displayed higher externally focused attention, positive affect, and lower ratings of perceived exertion, followed by greater enjoyment and future intention to participate in outdoor walking. The more externally focused attention predicted greater future intentions to participate in walking. Therefore, women with obesity self-selected an appropriate exercise intensity to improve fitness and health in both environmental settings. Also, self-paced outdoor walking presented improved psychological responses. Health care professionals should consider promoting outdoor forms of exercise to maximize psychological benefits and promote long-term adherence to a physically active lifestyle.

Learn More Breathe Better

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Chronic obstructive pulmonary disease (COPD) is a serious lung disease that makes breathing very difficult and can affect your quality of life. Learn the causes of COPD and what you can do to prevent it.

Lower limb joint moment during walking in water.

Science.gov (United States)

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

2003-11-04

Walking in water is a widely used rehabilitation method for patients with orthopedic disorders or arthritis, based on the belief that the reduction of weight in water makes it a safer medium and prevents secondary injuries of the lower-limb joints. To our knowledge, however, no experimental data on lower-limb joint moment during walking in water is available. The aim of this study was to quantify the joint moments of the ankle, knee, and hip during walking in water in comparison with those on land. Eight healthy volunteers walked on land and in water at a speed comfortable for them. A video-motion analysis system and waterproof force platform were used to obtain kinematic data and to calculate the joint moments. The hip joint moment was shown to be an extension moment almost throughout the stance phase during walking in water, while it changed from an extension- to flexion-direction during walking on land. The knee joint moment had two extension peaks during walking on land, whereas it had only one extension peak, a late one, during walking in water. The ankle joint moment during walking in water was considerably reduced but in the same direction, plantarflexion, as that during walking on land. The joint moments of the hip, knee, and ankle were not merely reduced during walking in water; rather, inter-joint coordination was totally changed.

Continuous-time quantum walks on star graphs

International Nuclear Information System (INIS)

Salimi, S.

2009-01-01

In this paper, we investigate continuous-time quantum walk on star graphs. It is shown that quantum central limit theorem for a continuous-time quantum walk on star graphs for N-fold star power graph, which are invariant under the quantum component of adjacency matrix, converges to continuous-time quantum walk on K 2 graphs (complete graph with two vertices) and the probability of observing walk tends to the uniform distribution.

Walk well: a randomised controlled trial of a walking intervention for adults with intellectual disabilities: study protocol

Science.gov (United States)

2013-01-01

Background Walking interventions have been shown to have a positive impact on physical activity (PA) levels, health and wellbeing for adult and older adult populations. There has been very little work carried out to explore the effectiveness of walking interventions for adults with intellectual disabilities. This paper will provide details of the Walk Well intervention, designed for adults with intellectual disabilities, and a randomised controlled trial (RCT) to test its effectiveness. Methods/design This study will adopt a RCT design, with participants allocated to the walking intervention group or a waiting list control group. The intervention consists of three PA consultations (baseline, six weeks and 12 weeks) and an individualised 12 week walking programme. A range of measures will be completed by participants at baseline, post intervention (three months from baseline) and at follow up (three months post intervention and six months from baseline). All outcome measures will be collected by a researcher who will be blinded to the study groups. The primary outcome will be steps walked per day, measured using accelerometers. Secondary outcome measures will include time spent in PA per day (across various intensity levels), time spent in sedentary behaviour per day, quality of life, self-efficacy and anthropometric measures to monitor weight change. Discussion Since there are currently no published RCTs of walking interventions for adults with intellectual disabilities, this RCT will examine if a walking intervention can successfully increase PA, health and wellbeing of adults with intellectual disabilities. Trial registration ISRCTN: ISRCTN50494254 PMID:23816316

Fractional scaling of quantum walks on percolation lattices

International Nuclear Information System (INIS)

Kendon, Viv; Knott, Paul; Leung, Godfrey; Bailey, Joe

2011-01-01

Quantum walks can be used to model processes such as transport in spin chains and bio-molecules. The enhanced spreading and mixing properties of quantum walks compared with their classical counterparts have been well-studied on regular structures and also shown to be sensitive to defects and imperfections. Using numerical simulation, we study the spreading properties of quantum walks on percolation lattices for both bond and site percolation. The randomly missing edges or sites provide a controlled amount of disorder in the regular Cartesian lattice. In one dimension (the line) we introduce a simple model of quantum tunneling to allow the walk to proceed past the missing edges or sites. This allows the quantum walk to spread faster than a classical random walk for short times, but at longer times the disorder localises the quantum walk. In two dimensions, we observe fractional scaling of the spreading with the number of steps of the walk. For percolation above the 85% level, we obtain faster spreading than classical random walks on the full lattice.

A cross-sectional study of breath acetone based on diabetic metabolic disorders.

Science.gov (United States)

Li, Wenwen; Liu, Yong; Lu, Xiaoyong; Huang, Yanping; Liu, Yu; Cheng, Shouquan; Duan, Yixiang

2015-02-26

Breath acetone is a known biomarker for diabetes mellitus in breath analysis. In this work, a cross-sectional study of breath acetone based on clinical metabolic disorders of type 2 diabetes mellitus (T2DM) was carried out. Breath acetone concentrations of 113 T2DM patients and 56 apparently healthy individuals were measured at a single time point. Concentrations varied from 0.22 to 9.41 ppmv (mean 1.75 ppmv) for T2DM, which were significantly higher than those for normal controls (ranged from 0.32 to 1.96 ppmv, mean 0.72 ppmv, p = 0.008). Observations in our work revealed that breath acetone concentrations elevated to different degrees, along with the abnormality of blood glucose, glycated hemoglobin (HbA1c), triglyceride and cholesterol. Breath acetone showed obviously positive correlations with blood ketone and urine ketone. Possible metabolic relations between breath acetone and diabetic disorders were also discussed. This work aimed at giving an overall assessment of breath acetone from the perspective of clinical parameters for type 2 diabetes.

Mechanical design of walking machines.

Science.gov (United States)

Arikawa, Keisuke; Hirose, Shigeo

2007-01-15

The performance of existing actuators, such as electric motors, is very limited, be it power-weight ratio or energy efficiency. In this paper, we discuss the method to design a practical walking machine under this severe constraint with focus on two concepts, the gravitationally decoupled actuation (GDA) and the coupled drive. The GDA decouples the driving system against the gravitational field to suppress generation of negative power and improve energy efficiency. On the other hand, the coupled drive couples the driving system to distribute the output power equally among actuators and maximize the utilization of installed actuator power. First, we depict the GDA and coupled drive in detail. Then, we present actual machines, TITAN-III and VIII, quadruped walking machines designed on the basis of the GDA, and NINJA-I and II, quadruped wall walking machines designed on the basis of the coupled drive. Finally, we discuss walking machines that travel on three-dimensional terrain (3D terrain), which includes the ground, walls and ceiling. Then, we demonstrate with computer simulation that we can selectively leverage GDA and coupled drive by walking posture control.

The lung cancer breath signature: a comparative analysis of exhaled breath and air sampled from inside the lungs

Science.gov (United States)

Capuano, Rosamaria; Santonico, Marco; Pennazza, Giorgio; Ghezzi, Silvia; Martinelli, Eugenio; Roscioni, Claudio; Lucantoni, Gabriele; Galluccio, Giovanni; Paolesse, Roberto; di Natale, Corrado; D'Amico, Arnaldo

2015-11-01

Results collected in more than 20 years of studies suggest a relationship between the volatile organic compounds exhaled in breath and lung cancer. However, the origin of these compounds is still not completely elucidated. In spite of the simplistic vision that cancerous tissues in lungs directly emit the volatile metabolites into the airways, some papers point out that metabolites are collected by the blood and then exchanged at the air-blood interface in the lung. To shed light on this subject we performed an experiment collecting both the breath and the air inside both the lungs with a modified bronchoscopic probe. The samples were measured with a gas chromatography-mass spectrometer (GC-MS) and an electronic nose. We found that the diagnostic capability of the electronic nose does not depend on the presence of cancer in the sampled lung, reaching in both cases an above 90% correct classification rate between cancer and non-cancer samples. On the other hand, multivariate analysis of GC-MS achieved a correct classification rate between the two lungs of only 76%. GC-MS analysis of breath and air sampled from the lungs demonstrates a substantial preservation of the VOCs pattern from inside the lung to the exhaled breath.

Thermodynamics and entanglements of walks under stress

International Nuclear Information System (INIS)

Janse van Rensburg, E J; Orlandini, E; Tesi, M C; Whittington, S G

2009-01-01

We use rigorous arguments and Monte Carlo simulations to study the thermodynamics and the topological properties of self-avoiding walks on the cubic lattice subjected to an external force f. The walks are anchored at one or both endpoints to an impenetrable plane at Z = 0 and the force is applied in the Z-direction. If a force is applied to the free endpoint of an anchored walk, then a model of pulled walks is obtained. If the walk is confined to a slab and a force is applied to the top bounding plane, then a model of stretched walks is obtained. For both models we prove the existence of the limiting free energy for any value of the force and we show that, for compressive forces, the thermodynamic properties of the two models differ substantially. For pulled walks we prove the existence of a phase transition that, by numerical simulation, we estimate to be second order and located at f = 0. By using a pattern theorem for large positive forces we show that almost all sufficiently long stretched walks are knotted. We examine the entanglement complexity of stretched and pulled walks; our numerical results show a sharp reduction with increasing pulling and stretching forces. Finally, we also examine models of pulled and stretched loops. We prove the existence of limiting free energies in these models and consider the knot probability numerically as a function of the applied pulling or stretching force

Noise Reduction in Breath Sound Files Using Wavelet Transform Based Filter

Science.gov (United States)

Syahputra, M. F.; Situmeang, S. I. G.; Rahmat, R. F.; Budiarto, R.

2017-04-01

The development of science and technology in the field of healthcare increasingly provides convenience in diagnosing respiratory system problem. Recording the breath sounds is one example of these developments. Breath sounds are recorded using a digital stethoscope, and then stored in a file with sound format. This breath sounds will be analyzed by health practitioners to diagnose the symptoms of disease or illness. However, the breath sounds is not free from interference signals. Therefore, noise filter or signal interference reduction system is required so that breath sounds component which contains information signal can be clarified. In this study, we designed a filter called a wavelet transform based filter. The filter that is designed in this study is using Daubechies wavelet with four wavelet transform coefficients. Based on the testing of the ten types of breath sounds data, the data is obtained in the largest SNRdB bronchial for 74.3685 decibels.

Relationship between musical characteristics and temporal breathing pattern in piano performance

Directory of Open Access Journals (Sweden)

Yutaka Sakaguchi

2016-07-01

Full Text Available Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon’s exercise, J. S. Bach’s Invention, Mozart’s Sonatas, and Debussy’s Clair de lune, was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. 1 Mean breath interval was shortened for excerpts in faster tempi. 2 Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. 3 Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise, but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. 4 Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. 5 Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists.

Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance.

Science.gov (United States)

Sakaguchi, Yutaka; Aiba, Eriko

2016-01-01

Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon's exercise, J. S. Bach's Invention, Mozart's Sonatas, and Debussy's Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists.

Walking, running, and resting under time, distance, and average speed constraints: optimality of walk-run-rest mixtures.

Science.gov (United States)

Long, Leroy L; Srinivasan, Manoj

2013-04-06

On a treadmill, humans switch from walking to running beyond a characteristic transition speed. Here, we study human choice between walking and running in a more ecological (non-treadmill) setting. We asked subjects to travel a given distance overground in a given allowed time duration. During this task, the subjects carried, and could look at, a stopwatch that counted down to zero. As expected, if the total time available were large, humans walk the whole distance. If the time available were small, humans mostly run. For an intermediate total time, humans often use a mixture of walking at a slow speed and running at a higher speed. With analytical and computational optimization, we show that using a walk-run mixture at intermediate speeds and a walk-rest mixture at the lowest average speeds is predicted by metabolic energy minimization, even with costs for transients-a consequence of non-convex energy curves. Thus, sometimes, steady locomotion may not be energy optimal, and not preferred, even in the absence of fatigue. Assuming similar non-convex energy curves, we conjecture that similar walk-run mixtures may be energetically beneficial to children following a parent and animals on long leashes. Humans and other animals might also benefit energetically from alternating between moving forward and standing still on a slow and sufficiently long treadmill.

Sleep-disordered breathing and mortality: a prospective cohort study.

OpenAIRE

Naresh M Punjabi; Brian S Caffo; James L Goodwin; Daniel J Gottlieb; Anne B Newman; George T O'Connor; David M Rapoport; Susan Redline; Helaine E Resnick; John A Robbins; Eyal Shahar; Mark L Unruh; Jonathan M Samet

2009-01-01

Editors' Summary Background About 1 in 10 women and 1 in 4 men have a chronic condition called sleep-disordered breathing although most are unaware of their problem. Sleep-disordered breathing, which is commonest in middle-aged and elderly people, is characterized by numerous, brief (10 second or so) interruptions of breathing during sleep. These interruptions, which usually occur when relaxation of the upper airway muscles decreases airflow, lower the level of oxygen in the blood and, as a r...

Walking training associated with virtual reality-based training increases walking speed of individuals with chronic stroke: systematic review with meta-analysis

OpenAIRE

Juliana M. Rodrigues-Baroni; Lucas R. Nascimento; Louise Ada; Luci F. Teixeira-Salmela

2014-01-01

OBJECTIVE: To systematically review the available evidence on the efficacy of walking training associated with virtual reality-based training in patients with stroke. The specific questions were: Is walking training associated with virtual reality-based training effective in increasing walking speed after stroke? Is this type of intervention more effective in increasing walking speed, than non-virtual reality-based walking interventions? METHOD: A systematic review with meta-analysis of rando...

Neighborhood preference, walkability and walking in overweight/obese men.

Science.gov (United States)

Norman, Gregory J; Carlson, Jordan A; O'Mara, Stephanie; Sallis, James F; Patrick, Kevin; Frank, Lawrence D; Godbole, Suneeta V

2013-03-01

To investigate whether self-selection moderated the effects of walkability on walking in overweight and obese men. 240 overweight and obese men completed measures on importance of walkability when choosing a neighborhood (selection) and preference for walkable features in general (preference). IPAQ measured walking. A walkbility index was derived from geographic information systems (GIS). Walkability was associated with walking for transportation (p = .027) and neighborhood selection was associated with walking for transportation (p = .002) and total walking (p = .001). Preference was associated with leisure walking (p = .045) and preference moderated the relationship between walkability and total walking (p = .059). Walkability and self-selection are both important to walking behavior.

Impact of breath holding on cardiovascular respiratory and cerebrovascular health.

Science.gov (United States)

Dujic, Zeljko; Breskovic, Toni

2012-06-01

Human underwater breath-hold diving is a fascinating example of applied environmental physiology. In combination with swimming, it is one of the most popular forms of summer outdoor physical activities. It is performed by a variety of individuals ranging from elite breath-hold divers, underwater hockey and rugby players, synchronized and sprint swimmers, spear fishermen, sponge harvesters and up to recreational swimmers. Very few data currently exist concerning the influence of regular breath holding on possible health risks such as cerebrovascular, cardiovascular and respiratory diseases. A literature search of the PubMed electronic search engine using keywords 'breath-hold diving' and 'apnoea diving' was performed. This review focuses on recent advances in knowledge regarding possibly harmful physiological changes and/or potential health risks associated with breath-hold diving. Available evidence indicates that deep breath-hold dives can be very dangerous and can cause serious acute health problems such a collapse of the lungs, barotrauma at descent and ascent, pulmonary oedema and alveolar haemorrhage, cardiac arrest, blackouts, nitrogen narcosis, decompression sickness and death. Moreover, even shallow apnoea dives, which are far more frequent, can present a significant health risk. The state of affairs is disturbing as athletes, as well as recreational individuals, practice voluntary apnoea on a regular basis. Long-term health risks of frequent maximal breath holds are at present unknown, but should be addressed in future research. Clearly, further studies are needed to better understand the mechanisms related to the possible development or worsening of different clinical disorders in recreational or competitive breath holding and to determine the potential changes in training/competition regimens in order to prevent these adverse events.

Nordic Walking Practice Might Improve Plantar Pressure Distribution

Science.gov (United States)

Perez-Soriano, Pedro; Llana-Belloch, Salvador; Martinez-Nova, Alfonso; Morey-Klapsing, G.; Encarnacion-Martinez, Alberto

2011-01-01

Nordic walking (NW), characterized by the use of two walking poles, is becoming increasingly popular (Morgulec-Adamowicz, Marszalek, & Jagustyn, 2011). We studied walking pressure patterns of 20 experienced and 30 beginner Nordic walkers. Plantar pressures from nine foot zones were measured during trials performed at two walking speeds (preferred…

21 CFR 868.5260 - Breathing circuit bacterial filter.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing circuit bacterial filter. 868.5260 Section 868.5260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... filter. (a) Identification. A breathing circuit bacterial filter is a device that is intended to remove...

Design with the feet: walking methods and participatory design

DEFF Research Database (Denmark)

Kanstrup, Anne Marie; Bertelsen, Pernille; Madsen, Jacob Østergaard

2014-01-01

This paper presents an analysis of walking methods and their relation to participatory design (PD). The paper includes a study of walking methods found in the literature and an empirical study of transect walks in a PD project. From this analysis, we identify central attributes of, and challenges...... to, PD walks. Walking with people in the context of design is a natural activity for the participatory designer, who acknowledges the importance of immersion and relationships in design. However, the various intentions of walking approaches indicate an underacknowledged awareness of walking methods...

Does getting a dog increase recreational walking?

Directory of Open Access Journals (Sweden)

Knuiman Matthew W

2008-03-01

Full Text Available Abstract Background This study examines changes in socio-demographic, environmental and intrapersonal factors associated with dog acquisition in non-dog owners at baseline to 12-months follow-up and the effect of dog acquisition on minutes per week of recreational walking. Methods RESIDE study participants completed self-administered questionnaires (baseline and 12-months follow-up measuring physical activity, dog ownership, dog walking behavior as well as environmental, intrapersonal and socio-demographic factors. Analysis was restricted to 'Continuing non-owners' (i.e., non-owners at both baseline and follow-up; n = 681 and 'New dog owners' (i.e., non-owners who acquired a dog by follow-up; n = 92. Results Overall, 12% of baseline non-owners had acquired a dog at follow-up. Dog acquisition was associated with working and having children at home. Those who changed from single to couple marital status were also more likely to acquire a dog. The increase in minutes of walking for recreation within the neighborhood from baseline to follow-up was 48 minutes/week for new dog owners compared with 12 minutes/week for continuing non-owners (p p p > 0.05 after further adjustment for change in baseline to follow-up variables. Increase in intention to walk was the main factor contributing to attenuation of the effect of dog acquisition on recreational walking. Conclusion This study used a large representative sample of non-owners to examine the relationship between dog acquisition and recreational walking and provides evidence to suggest that dog acquisition leads to an increase in walking. The most likely mechanism through which dog acquisition facilitates increased physical activity is through behavioral intention via the dog's positive effect on owner's cognitive beliefs about walking, and through the provision of motivation and social support for walking. The results suggest that behavioral intention mediates the relationship between dog acquisition

Probability distributions for Markov chain based quantum walks

Science.gov (United States)

Balu, Radhakrishnan; Liu, Chaobin; Venegas-Andraca, Salvador E.

2018-01-01

We analyze the probability distributions of the quantum walks induced from Markov chains by Szegedy (2004). The first part of this paper is devoted to the quantum walks induced from finite state Markov chains. It is shown that the probability distribution on the states of the underlying Markov chain is always convergent in the Cesaro sense. In particular, we deduce that the limiting distribution is uniform if the transition matrix is symmetric. In the case of a non-symmetric Markov chain, we exemplify that the limiting distribution of the quantum walk is not necessarily identical with the stationary distribution of the underlying irreducible Markov chain. The Szegedy scheme can be extended to infinite state Markov chains (random walks). In the second part, we formulate the quantum walk induced from a lazy random walk on the line. We then obtain the weak limit of the quantum walk. It is noted that the current quantum walk appears to spread faster than its counterpart-quantum walk on the line driven by the Grover coin discussed in literature. The paper closes with an outlook on possible future directions.

14C-urea breath test for the detection of Helicobacter pylori

International Nuclear Information System (INIS)

Veldhuyzen van Zanten, S.J.; Tytgat, K.M.; Hollingsworth, J.; Jalali, S.; Rshid, F.A.; Bowen, B.M.; Goldie, J.; Goodacre, R.L.; Riddell, R.H.; Hunt, R.H.

1990-01-01

The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14 C-urea breath test which uses 5 microCi 14 C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared the outcome of the breath test to the results of histology and culture of endoscopically obtained gastric biopsies in 84 patients. The breath test discriminated well between the 50 positive patients and the 34 patients negative for Helicobacter pylori: the calculated sensitivity was 100%, specificity 88%, positive predictive value 93%, and negative predictive value 100%. Treatment with bismuth subsalicylate and/or ampicillin resulted in lower counts of exhaled 14 CO 2 which correlated with histological improvement in gastritis. The 14 C-urea breath test is a better gold standard for the detection of Helicobacter pylori than histology and/or culture

Apparatus and method for monitoring breath acetone and diabetic diagnostics

Science.gov (United States)

Duan, Yixiang [Los Alamos, NM; Cao, Wenqing [Los Alamos, NM

2008-08-26

An apparatus and method for monitoring diabetes through breath acetone detection and quantitation employs a microplasma source in combination with a spectrometer. The microplasma source provides sufficient energy to produce excited acetone fragments from the breath gas that emit light. The emitted light is sent to the spectrometer, which generates an emission spectrum that is used to detect and quantify acetone in the breath gas.

Walking around to grasp interaction

DEFF Research Database (Denmark)

Lykke, Marianne; Jantzen, Christian

2013-01-01

The paper presents experiences from a study using walk-alongs to provide insight into museum visitors’ experience with interactive features of sound art installations. The overall goal of the study was to learn about the participants’ opinions and feelings about the possibility of interaction...... with the sound installations. The aim was to gain an understanding of the role of the in-teraction, if interaction makes a difference for the understanding of the sound art. 30 walking interviews were carried out at ZKM, Karlsruhe with a total of 57 museum guests, individuals or groups. During the walk......-alongs the research-ers acted as facilitators and partners in the engagement with the sound installa-tions. The study provided good insight into advantages and challenges with the walk-along method, for instance the importance of shared, embodied sensing of space for the understanding of the experience. The common...

Measuring breath acetone for monitoring fat loss: Review.

Science.gov (United States)

Anderson, Joseph C

2015-12-01

Endogenous acetone production is a by-product of the fat metabolism process. Because of its small size, acetone appears in exhaled breath. Historically, endogenous acetone has been measured in exhaled breath to monitor ketosis in healthy and diabetic subjects. Recently, breath acetone concentration (BrAce) has been shown to correlate with the rate of fat loss in healthy individuals. In this review, the measurement of breath acetone in healthy subjects is evaluated for its utility in predicting fat loss and its sensitivity to changes in physiologic parameters. BrAce can range from 1 ppm in healthy non-dieting subjects to 1,250 ppm in diabetic ketoacidosis. A strong correlation exists between increased BrAce and the rate of fat loss. Multiple metabolic and respiratory factors affect the measurement of BrAce. BrAce is most affected by changes in the following factors (in descending order): dietary macronutrient composition, caloric restriction, exercise, pulmonary factors, and other assorted factors that increase fat metabolism or inhibit acetone metabolism. Pulmonary factors affecting acetone exchange in the lung should be controlled to optimize the breath sample for measurement. When biologic factors are controlled, BrAce measurement provides a non-invasive tool for monitoring the rate of fat loss in healthy subjects. © 2015 The Authors Obesity published by Wiley Periodicals, Inc. on behalf of The Obesity Society (TOS).

Cell phones change the way we walk.

Science.gov (United States)

Lamberg, Eric M; Muratori, Lisa M

2012-04-01

Cell phone use among pedestrians leads to increased cognitive distraction, reduced situation awareness and increases in unsafe behavior. Performing a dual-task, such as talking or texting with a cell phone while walking, may interfere with working memory and result in walking errors. At baseline, thirty-three participants visually located a target 8m ahead; then vision was occluded and they were instructed to walk to the remembered target. One week later participants were assigned to either walk, walk while talking on a cell phone, or walk while texting on a cell phone toward the target with vision occluded. Duration and final location of the heel were noted. Linear distance traveled, lateral angular deviation from the start line, and gait velocity were derived. Changes from baseline to testing were analyzed with paired t-tests. Participants engaged in cell phone use presented with significant reductions in gait velocity (texting: 33% reduction, p=0.01; talking: 16% reduction, p=0.02). Moreover, participants who were texting while walking demonstrated a 61% increase in lateral deviation (p=0.04) and 13% increase in linear distance traveled (p=0.03). These results suggest that the dual-task of walking while using a cell phone impacts executive function and working memory and influences gait to such a degree that it may compromise safety. Importantly, comparison of the two cell phone conditions demonstrates texting creates a significantly greater interference effect on walking than talking on a cell phone. Copyright © 2011 Elsevier B.V. All rights reserved.

Urban walking: Perspectives of locals and tourists

Directory of Open Access Journals (Sweden)

Farkić Jelena

2015-01-01

Full Text Available Urban planners and architects have done extensive research on walk ability: what it means and how it correlates with urban design and quality of life of the locals, however, it has been hitherto neglected from the aspect of tourism studies. Many cities worldwide are or tend to be walkable as this leads to more sustainable and prosperous communities. In addition, walking-friendly environments greatly cater for leisure and tourism, as in many cities, walking is an integral part of tourist experience. Therefore, tourism industry can be of tremendous help for the city authorities in understanding walkers' needs and experiences. Taking into account both the locals and tourists, this research sought to: (1 determine the most frequently utilized modes of transportation in Novi Sad in Serbia and Koper in Slovenia; (2 assess thier reasons for walking and perception of the quality of pedestrian infrastructure; and (3 evaluate the psychometric properties of the questionnaire designed for the purpose of this study. The results show that the great majority of respondents walk in these two cities. The locals walk primarily to achieve physical fitness, whereas tourists walk primarily to explore the urban spaces. This makes more space for tourism as it combines a competitive supply able to meet visitors' expectations with a positive contribution to the sustainable development of cities and well-being of their residents. Furthermore, this study contributes to emphasizing walking as a sustainable form of mobility in urban environment and can be the impetus for profiling Novi Sad and Koper as walking-friendly cities.

14C-urea breath test in the detection of Helicobacter pylori infection

International Nuclear Information System (INIS)

Artiko, V.M.; Obradovic, V.B.; Petrovic, N.S.; Davidovic, B.M.; Grujic-Adanja, G.S.; Nastic-Miric, D.R.; Milosavljevic, T.N.

2001-01-01

Helicobacter pylori infection is supposed to be one of the major causes of digestive and other diseases. Among a lot of invasive and non-invasive methods for its detection, none is ideal. The aim is an assessment of the Helicobacter pylori infection in the stomach using breath test and comparison to other diagnostic methods, as well as following up the effects of therapy. In 17 patients with digestive discomfort, breath test, rapid urease test and histology were performed, while in 47 patients with proven HP infection the effect of therapy was followed up using breath test and clinical findings. Breath test was performed after per oral administration of the capsule of 14 C urea (37 kBq). Findings of the breath and urease tests were in accordance in 14/17 patients (83%) while breath test and histology in 16/17 patients (94%). During follow-up of the therapeutic effects, breath test and clinical findings were in accordance in 43/47 patients (98%). Breath test can be useful in diagnosis but is a method of choice in following up the patients after therapy for H. pylori infection, because it is non-invasive, fast and precise. (author)

Measurement and prediction of indoor air quality using a breathing thermal manikin.

Science.gov (United States)

Melikov, A; Kaczmarczyk, J

2007-02-01

The analyses performed in this paper reveal that a breathing thermal manikin with realistic simulation of respiration including breathing cycle, pulmonary ventilation rate, frequency and breathing mode, gas concentration, humidity and temperature of exhaled air and human body shape and surface temperature is sensitive enough to perform reliable measurement of characteristics of air as inhaled by occupants. The temperature, humidity, and pollution concentration in the inhaled air can be measured accurately with a thermal manikin without breathing simulation if they are measured at the upper lip at a distance of measured inhaled air parameters. Proper simulation of breathing, especially of exhalation, is needed for studying the transport of exhaled air between occupants. A method for predicting air acceptability based on inhaled air parameters and known exposure-response relationships established in experiments with human subjects is suggested. Recommendations for optimal simulation of human breathing by means of a breathing thermal manikin when studying pollution concentration, temperature and humidity of the inhaled air as well as the transport of exhaled air (which may carry infectious agents) between occupants are outlined. In order to compare results obtained with breathing thermal manikins, their nose and mouth geometry should be standardized.

Sleep disordered breathing in spinal cord injury: A systematic review.

Science.gov (United States)

Chiodo, Anthony E; Sitrin, Robert G; Bauman, Kristy A

2016-07-01

Spinal cord injury commonly results in neuromuscular weakness that impacts respiratory function. This would be expected to be associated with an increased likelihood of sleep-disordered breathing. (1) Understand the incidence and prevalence of sleep disordered breathing in spinal cord injury. (2) Understand the relationship between injury and patient characteristics and the incidence of sleep disordered breathing in spinal cord injury. (3) Distinguish between obstructive sleep apnea and central sleep apnea incidence in spinal cord injury. (4) Clarify the relationship between sleep disordered breathing and stroke, myocardial infarction, metabolic dysfunction, injuries, autonomic dysreflexia and spasticity incidence in persons with spinal cord injury. (5) Understand treatment tolerance and outcome in persons with spinal cord injury and sleep disordered breathing. Extensive database search including PubMed, Cochrane Library, CINAHL and Web of Science. Given the current literature limitations, sleep disordered breathing as currently defined is high in patients with spinal cord injury, approaching 60% in motor complete persons with tetraplegia. Central apnea is more common in patients with tetraplegia than in patients with paraplegia. Early formal sleep study in patients with acute complete tetraplegia is recommended. In patients with incomplete tetraplegia and with paraplegia, the incidence of sleep-disordered breathing is significantly higher than the general population. With the lack of correlation between symptoms and SDB, formal study would be reasonable. There is insufficient evidence in the literature on the impact of treatment on morbidity, mortality and quality of life outcomes.

Methodological aspects of breath hydrogen (H2) analysis. Evaluation of a H2 monitor and interpretation of the breath H2 test

DEFF Research Database (Denmark)

Rumessen, J J; Kokholm, G; Gudmand-Høyer, E

1987-01-01

The reliability of end-expiratory hydrogen (H2) breath tests were assessed and the significance of some important pitfalls were studied, using a compact, rapid H2-monitor with electrochemical cells. The H2 response was shown to be linear and stable. The reproducibility of the breath collection...... were studied in 10 healthy adults during a 4-month period and they showed very marked inter- and intra-individual variability (16% above 40 p.p.m.). Initial peaks (early, short-lived H2 rises unrelated to carbohydrate malabsorption) were identified in 25% of the breath tests (in 4% above 20 p.......p.m). It is concluded that the technique used for interval sampling of end-expiratory breath samples for H2 concentration gives reliable results. The biological significance of H2 concentration increments can only be evaluated if the limitations of the technical procedures and the individual ability to produce H2...

The Breath of Chemistry

DEFF Research Database (Denmark)

Josephsen, Jens

The present preliminary text is a short thematic presentation in biological inorganic chemistry meant to illustrate general and inorganic (especially coordination) chemistry in biochemistry. The emphasis is on molecular models to explain features of the complicated mechanisms essential to breathing...

Cardio-metabolic Diseases Prevention by Self-monitoring the Breath

Directory of Open Access Journals (Sweden)

Danila GERMANESE

2017-08-01

Full Text Available As new as very promising technique, breath analysis allows for monitoring the biochemical processes that occur in human body in a non-invasive way. Nevertheless, the high costs for standard analytical instrumentation (i.e., gas chromatograph, mass spectrometer, the need for specialized personnel able to read the results and the lack of protocols to collect breath samples, set limit to the exploitation of breath analysis in clinical practice. Here, we describe the development of a device, named Wize Sniffer, which is portable and entirely based on low cost technology: it uses an array of commercial, semiconductor gas sensors and a widely employed open source controller, an Arduino Mega2560 with Ethernet module. In addition, it is very easy-to-use also for non-specialized personnel and able to analyze in real time the composition of the breath. The Wize Sniffer is composed of three modules: signal measurement module, signal conditioning module and signal processing module. The idea was born in the framework of European SEMEiotic Oriented Technology for Individual's CardiOmetabolic risk self-assessmeNt and Self-monitoring (SEMEOTICONS Project, in order to monitor individual's lifestyle by detecting in the breath those molecules related to the noxious habits for cardio-metabolic risk (alcohol intake, smoking, wrong diet. Nonetheless, the modular configuration of the device allows for changing the sensors according to the molecules to be detected, thus fully exploiting the potential of breath analysis.

Transition in organ function during the evolution of air-breathing; insights from Arapaima gigas, an obligate air-breathing teleost from the Amazon.

Science.gov (United States)

Brauner, C J; Matey, V; Wilson, J M; Bernier, N J; Val, A L

2004-04-01

The transition from aquatic to aerial respiration is associated with dramatic physiological changes in relation to gas exchange, ion regulation, acid-base balance and nitrogenous waste excretion. Arapaima gigas is one of the most obligate extant air-breathing fishes, representing a remarkable model system to investigate (1) how the transition from aquatic to aerial respiration affects gill design and (2) the relocation of physiological processes from the gills to the kidney during the evolution of air-breathing. Arapaima gigas undergoes a transition from water- to air-breathing during development, resulting in striking changes in gill morphology. In small fish (10 g), the gills are qualitatively similar in appearance to another closely related water-breathing fish (Osteoglossum bicirrhosum); however, as fish grow (100-1000 g), the inter-lamellar spaces become filled with cells, including mitochondria-rich (MR) cells, leaving only column-shaped filaments. At this stage, there is a high density of MR cells and strong immunolocalization of Na(+)/K(+)-ATPase along the outer cell layer of the gill filament. Despite the greatly reduced overall gill surface area, which is typical of obligate air-breathing fish, the gills may remain an important site for ionoregulation and acid-base regulation. The kidney is greatly enlarged in A. gigas relative to that in O. bicirrhosum and may comprise a significant pathway for nitrogenous waste excretion. Quantification of the physiological role of the gill and the kidney in A. gigas during development and in adults will yield important insights into developmental physiology and the evolution of air-breathing.

Comparison of two single-breath-held 3-D acquisitions with multi-breath-held 2-D cine steady-state free precession MRI acquisition in children with single ventricles

Energy Technology Data Exchange (ETDEWEB)

Atweh, Lamya A.; Dodd, Nicholas A.; Krishnamurthy, Ramkumar; Chu, Zili D. [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Pednekar, Amol [Philips Healthcare, Houston, TX (United States); Krishnamurthy, Rajesh [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Baylor College of Medicine, Department of Radiology, Houston, TX (United States); Baylor College of Medicine, Department of Pediatrics, Houston, TX (United States)

2016-05-15

Breath-held two-dimensional balanced steady-state free precession cine acquisition (2-D breath-held SSFP), accelerated with parallel imaging, is the method of choice for evaluating ventricular function due to its superior blood-to-myocardial contrast, edge definition and high intrinsic signal-to-noise ratio throughout the cardiac cycle. The purpose of this study is to qualitatively and quantitatively compare the two different single-breath-hold 3-D cine SSFP acquisitions using 1) multidirectional sensitivity encoding (SENSE) acceleration factors (3-D multiple SENSE SSFP), and 2) k-t broad-use linear acceleration speed-up technique (3-D k-t SSFP) with the conventional 2-D breath-held SSFP in non-sedated asymptomatic volunteers and children with single ventricle congenital heart disease. Our prospective study was performed on 30 non-sedated subjects (9 healthy volunteers and 21 functional single ventricle patients), ages 12.5 +/- 2.8 years. Two-dimensional breath-held SSFP with SENSE acceleration factor of 2, eight-fold accelerated 3-D k-t SSFP, and 3-D multiple SENSE SSFP with total parallel imaging factor of 4 were performed to evaluate ventricular volumes and mass in the short-axis orientation. Image quality scores (blood myocardial contrast, edge definition and interslice alignment) and volumetric analysis (end systolic volume, end diastolic volume and ejection fraction) were performed on the data sets by experienced users. Paired t-test was performed to compare each of the 3-D k-t SSFP and 3-D multiple SENSE SSFP clinical scores against 2-D breath-held SSFP. Bland-Altman analysis was performed on left ventricle (LV) and single ventricle volumetry. Interobserver and intraobserver variability in volumetric measurements were determined using intraclass coefficients. The clinical scores were highest for the 2-D breath-held SSFP images. Between the two 3-D sequences, 3-D multiple SENSE SSFP performed better than 3-D k-t SSFP. Bland-Altman analysis for volumes

Breath hydrogen analysis in patients with ileoanal pouch anastomosis

DEFF Research Database (Denmark)

Bruun, E; Meyer, J N; Rumessen, J J

1995-01-01

The possible influence on functional outcomes of hydrogen production in the ileoanal pouch after restorative proctocolectomy was investigated by means of lactulose H2 breath tests. Eight of 15 patients had significant increases in breath hydrogen after 10 g lactulose. One patient declined...... to participate in further investigations, the remaining seven responders had no evidence of small bowel bacterial overgrowth after glucose H2 breath tests. The ability to produce hydrogen by anaerobic fermentation of lactulose in the pouch was unrelated to the age of the patients or of the pouch. Seven of eight...... responders had successive breath tests after ingestion of lactulose 20 g and wheat starch 100 g. Five of seven had significant increases after lactulose but none after wheat starch. The overall function of the pouch continence, spontaneity of defecation, and 24 hour stool frequency was significantly better...

A Pilot Study on the Effects of Slow Paced Breathing on Current Food Craving.

Science.gov (United States)

Meule, Adrian; Kübler, Andrea

2017-03-01

Heart rate variability biofeedback (HRV-BF) involves slow paced breathing (approximately six breaths per minute), thereby maximizing low-frequent heart rate oscillations and baroreflex gain. Mounting evidence suggests that HRV-BF promotes symptom reductions in a variety of physical and mental disorders. It may also positively affect eating behavior by reducing food cravings. The aim of the current study was to investigate if slow paced breathing can be useful for attenuating momentary food craving. Female students performed paced breathing either at six breaths per minute (n = 32) or at nine breaths per minute (n = 33) while watching their favorite food on the computer screen. Current food craving decreased during a first resting period, increased during paced breathing, and decreased during a second resting period in both conditions. Although current hunger increased in both conditions during paced breathing as well, it remained elevated after the second resting period in the nine breaths condition only. Thus, breathing rate did not influence specific food craving, but slow paced breathing appeared to have a delayed influence on state hunger. Future avenues are suggested for the study of HRV-BF in the context of eating behavior.

Lévy Walks Suboptimal under Predation Risk.

Directory of Open Access Journals (Sweden)

Masato S Abe

2015-11-01

Full Text Available A key challenge in movement ecology is to understand how animals move in nature. Previous studies have predicted that animals should perform a special class of random walks, called Lévy walk, to obtain more targets. However, some empirical studies did not support this hypothesis, and the relationship between search strategy and ecological factors is still unclear. We focused on ecological factors, such as predation risk, and analyzed whether Lévy walk may not be favored. It was remarkable that the ecological factors often altered an optimal search strategy from Lévy walk to Brownian walk, depending on the speed of the predator's movement, density of predators, etc. This occurred because higher target encounter rates simultaneously led searchers to higher predation risks. Our findings indicate that animals may not perform Lévy walks often, and we suggest that it is crucial to consider the ecological context for evaluating the search strategy performed by animals in the field.

Lévy Walks Suboptimal under Predation Risk

Science.gov (United States)

Abe, Masato S.; Shimada, Masakazu

2015-01-01

A key challenge in movement ecology is to understand how animals move in nature. Previous studies have predicted that animals should perform a special class of random walks, called Lévy walk, to obtain more targets. However, some empirical studies did not support this hypothesis, and the relationship between search strategy and ecological factors is still unclear. We focused on ecological factors, such as predation risk, and analyzed whether Lévy walk may not be favored. It was remarkable that the ecological factors often altered an optimal search strategy from Lévy walk to Brownian walk, depending on the speed of the predator’s movement, density of predators, etc. This occurred because higher target encounter rates simultaneously led searchers to higher predation risks. Our findings indicate that animals may not perform Lévy walks often, and we suggest that it is crucial to consider the ecological context for evaluating the search strategy performed by animals in the field. PMID:26544687

Natural Vibration of a Beam with a Breathing Oblique Crack

Directory of Open Access Journals (Sweden)

Yijiang Ma

2017-01-01

Full Text Available An analytical method is proposed to calculate the natural frequency of a cantilever beam with a breathing oblique crack. A double-linear-springs-model is developed in the modal analysis process to describe the breathing oblique crack, and the breathing behaviour of the oblique crack is objectively simulated. The finite element method (FEM analysis software ABAQUS is used to calculate the geometric correction factors when the cracked plate is subjected to a pure bending moment at different oblique crack angles and relative depths. The Galerkin method is applied to simplify the cracked beam to a single degree of freedom system, allowing the natural frequency of the beam with the breathing oblique crack to be calculated. Compared with the natural frequencies of the breathing oblique cracked beam obtained using the ABAQUS FEM method, the proposed analytical method exhibits a high computational accuracy, with a maximum error of only 4.65%.

Scaling of the atmosphere of self-avoiding walks

Energy Technology Data Exchange (ETDEWEB)

Owczarek, A L [Department of Mathematics and Statistics, The University of Melbourne, Victoria 3010 (Australia); Prellberg, T [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)], E-mail: a.owczarek@ms.unimelb.edu.au, E-mail: t.prellberg@qmul.ac.uk

2008-09-19

The number of free sites next to the end of a self-avoiding walk is known as the atmosphere of the walk. The average atmosphere can be related to the number of configurations. Here we study the distribution of atmospheres as a function of length and how the number of walks of fixed atmosphere scale. Certain bounds on these numbers can be proved. We use Monte Carlo estimates to verify our conjectures in two dimensions. Of particular interest are walks that have zero atmosphere, which are known as trapped. We demonstrate that these walks scale in the same way as the full set of self-avoiding walks, barring an overall constant factor.

Forced Air-Breathing PEMFC Stacks

Directory of Open Access Journals (Sweden)

K. S. Dhathathreyan

2012-01-01

Full Text Available Air-breathing fuel cells have a great potential as power sources for various electronic devices. They differ from conventional fuel cells in which the cells take up oxygen from ambient air by active or passive methods. The air flow occurs through the channels due to concentration and temperature gradient between the cell and the ambient conditions. However developing a stack is very difficult as the individual cell performance may not be uniform. In order to make such a system more realistic, an open-cathode forced air-breathing stacks were developed by making appropriate channel dimensions for the air flow for uniform performance in a stack. At CFCT-ARCI (Centre for Fuel Cell Technology-ARC International we have developed forced air-breathing fuel cell stacks with varying capacity ranging from 50 watts to 1500 watts. The performance of the stack was analysed based on the air flow, humidity, stability, and so forth, The major advantage of the system is the reduced number of bipolar plates and thereby reduction in volume and weight. However, the thermal management is a challenge due to the non-availability of sufficient air flow to remove the heat from the system during continuous operation. These results will be discussed in this paper.

Theme and variations: amphibious air-breathing intertidal fishes.

Science.gov (United States)

Martin, K L

2014-03-01

Over 70 species of intertidal fishes from 12 families breathe air while emerging from water. Amphibious intertidal fishes generally have no specialized air-breathing organ but rely on vascularized mucosae and cutaneous surfaces in air to exchange both oxygen and carbon dioxide. They differ from air-breathing freshwater fishes in morphology, physiology, ecology and behaviour. Air breathing and terrestrial activity are present to varying degrees in intertidal fish species, correlated with the tidal height of their habitat. The gradient of amphibious lifestyle includes passive remainers that stay in the intertidal zone as tides ebb, active emergers that deliberately leave water in response to poor aquatic conditions and highly mobile amphibious skipper fishes that may spend more time out of water than in it. Normal terrestrial activity is usually aerobic and metabolic rates in air and water are similar. Anaerobic metabolism may be employed during forced exercise or when exposed to aquatic hypoxia. Adaptations for amphibious life include reductions in gill surface area, increased reliance on the skin for respiration and ion exchange, high affinity of haemoglobin for oxygen and adjustments to ventilation and metabolism while in air. Intertidal fishes remain close to water and do not travel far terrestrially, and are unlikely to migrate or colonize new habitats at present, although in the past this may have happened. Many fish species spawn in the intertidal zone, including some that do not breathe air, as eggs and embryos that develop in the intertidal zone benefit from tidal air emergence. With air breathing, amphibious intertidal fishes survive in a variable habitat with minimal adjustments to existing structures. Closely related species in different microhabitats provide unique opportunities for comparative studies. © 2013 The Fisheries Society of the British Isles.

Robust and efficient walking with spring-like legs

Energy Technology Data Exchange (ETDEWEB)

Rummel, J; Blum, Y; Seyfarth, A, E-mail: juergen.rummel@uni-jena.d, E-mail: andre.seyfarth@uni-jena.d [Lauflabor Locomotion Laboratory, University of Jena, Dornburger Strasse 23, 07743 Jena (Germany)

2010-12-15

The development of bipedal walking robots is inspired by human walking. A way of implementing walking could be performed by mimicking human leg dynamics. A fundamental model, representing human leg dynamics during walking and running, is the bipedal spring-mass model which is the basis for this paper. The aim of this study is the identification of leg parameters leading to a compromise between robustness and energy efficiency in walking. It is found that, compared to asymmetric walking, symmetric walking with flatter angles of attack reveals such a compromise. With increasing leg stiffness, energy efficiency increases continuously. However, robustness is the maximum at moderate leg stiffness and decreases slightly with increasing stiffness. Hence, an adjustable leg compliance would be preferred, which is adaptable to the environment. If the ground is even, a high leg stiffness leads to energy efficient walking. However, if external perturbations are expected, e.g. when the robot walks on uneven terrain, the leg should be softer and the angle of attack flatter. In the case of underactuated robots with constant physical springs, the leg stiffness should be larger than k-tilde = 14 in order to use the most robust gait. Soft legs, however, lack in both robustness and efficiency.

Robust and efficient walking with spring-like legs

International Nuclear Information System (INIS)

Rummel, J; Blum, Y; Seyfarth, A

2010-01-01

The development of bipedal walking robots is inspired by human walking. A way of implementing walking could be performed by mimicking human leg dynamics. A fundamental model, representing human leg dynamics during walking and running, is the bipedal spring-mass model which is the basis for this paper. The aim of this study is the identification of leg parameters leading to a compromise between robustness and energy efficiency in walking. It is found that, compared to asymmetric walking, symmetric walking with flatter angles of attack reveals such a compromise. With increasing leg stiffness, energy efficiency increases continuously. However, robustness is the maximum at moderate leg stiffness and decreases slightly with increasing stiffness. Hence, an adjustable leg compliance would be preferred, which is adaptable to the environment. If the ground is even, a high leg stiffness leads to energy efficient walking. However, if external perturbations are expected, e.g. when the robot walks on uneven terrain, the leg should be softer and the angle of attack flatter. In the case of underactuated robots with constant physical springs, the leg stiffness should be larger than k-tilde = 14 in order to use the most robust gait. Soft legs, however, lack in both robustness and efficiency.

Breathing Air Purification for Hyperbaric Purposes, Part II

Directory of Open Access Journals (Sweden)

Woźniak Arkadiusz

2015-03-01

Full Text Available Determining the efficiency of breathing air purification for hyperbaric purposes with the use of filtration systems is of a crucial importance. However, when the Polish Navy took samples of breathing air from their own filtration plant for quality purposes, these were found to not meet the required standard. The identification of this problem imposed the need to undertake actions aimed at the elimination of the identified disruptions in the process of breathing air production, with the objective of assuring its proper quality. This study presents the results of the initial tests on the air supply sources utilised by the Polish Navy, which were carried out for the purpose of setting a proper direction of future works and implementing corrective measures in order to optimise the breathing air production process. The obtained test results will be used in a subsequent publication devoted to the assessment of the level of efficiency of air purification with the use of a multifaceted approach consisting in the utilisation of various types of air supply sources and different configurations of purification systems.

BREATHING EXERCISE RELAXATION INCREASE PHSYCOLOGICAL RESPONSE PRESCHOOL CHILDREN

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Yuni Sufyanti Arief

2017-07-01

Full Text Available Introduction: Being hospitalize will be made the children become stress. Hospitalization response of the child particularly is afraid sense regard to painfull procedure and increase to attack the invasive procedure. The aimed of this study was to describe the influence of breathing exercise relaxation technique regarded to phsycological receiving responses in the preeliminary school chidren while they were receiving invasive procedure. Method: A quasy experimental purposive sampling design was used in this study. There were 20 respondents who met to the inclusion criteria. The independent variable was the breathing exercise relaxation technique and the dependent variable was phsycological receiving responses. Data for phsylogical response were collected by using observation form then analyzed by using Wilcoxon Signed Rank Test and Mann Whitney U Test with significance level α≤0.05. Result :  The result showed that breathing exercise relaxation technique had significance influence to phsycological response (p=0.000. Discussion: It,s can be concluded that breathing exercise relaxation technique has an effect to increase pshycological response in preeliminary school children who received invasive procedure.

SU-F-T-415: Differences in Lung Sparing in Deep Inspiration Breath-Hold and Free Breathing Breast Plans Calculated in Pinnacle and Monaco

Energy Technology Data Exchange (ETDEWEB)

Saenz, D; Stathakis, S [University of Texas Health Science Center San Antonio, San Antonio, TX (United States)

2016-06-15

Purpose: Deep inspiration breath-hold (DIBH) is used for left-sided breast radiotherapy to spare the heart and lung. The magnitude of sparing has been shown to be significant. Monte Carlo, furthermore, has the potential to calculate most accurately the dose in the heterogeneous lung medium at the interface with the lung wall. The lung dose was investigated in Monaco to determine the level of sparing relative to that calculated in Pinnacle{sup 3}. Methods: Five patients undergoing DIBH radiotherapy on an Elekta Versa HD linear accelerator in conjunction with the Catalyst C-RAD surface imaging system were planned using Phillips Pinnacle{sup 3}. Free breathing plans were also created to clinically assure a benefit. Both plans were re-calculated in Monaco to determine if there were any significant differences. The mean heart dose, mean left lung, and mean total lung dose were compared in addition to the V20 for left and both lungs. Dose was calculated as dose to medium as well as dose to water with a statistical precision of 0.7%. Results: Mean lung dose was significantly different (p < 0.003) between the two calculations for both DIBH (11.6% higher in Monaco) and free breathing (14.2% higher in Monaco). V20 was also higher in Monaco (p < 0.05) for DIBH (5.7% higher) and free breathing (4.9% higher). The mean heart dose was not significantly different between the dose calculations for either DIBH or free breathing. Results were no more than 0.1% different when calculated as dose to water. Conclusion: The use of Monte Carlo can provide insight on the lung dose for both free breathing and DIBH techniques for whole breast irradiation. While the sparing (dose reductions with DIBH as compared to free breathing) is equivalent for either planning system, the lung doses themselves are higher when calculated with Monaco.

Locally Perturbed Random Walks with Unbounded Jumps

OpenAIRE

Paulin, Daniel; Szász, Domokos

2010-01-01

In \\cite{SzT}, D. Sz\\'asz and A. Telcs have shown that for the diffusively scaled, simple symmetric random walk, weak convergence to the Brownian motion holds even in the case of local impurities if $d \\ge 2$. The extension of their result to finite range random walks is straightforward. Here, however, we are interested in the situation when the random walk has unbounded range. Concretely we generalize the statement of \\cite{SzT} to unbounded random walks whose jump distribution belongs to th...

Air-Breathing Launch Vehicle Technology Being Developed

Science.gov (United States)

Trefny, Charles J.

2003-01-01

Of the technical factors that would contribute to lowering the cost of space access, reusability has high potential. The primary objective of the GTX program is to determine whether or not air-breathing propulsion can enable reusable single-stage-to-orbit (SSTO) operations. The approach is based on maturation of a reference vehicle design with focus on the integration and flight-weight construction of its air-breathing rocket-based combined-cycle (RBCC) propulsion system.

Kinematic evaluation of virtual walking trajectories.

Science.gov (United States)

Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

2013-04-01

Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

Fermionic entanglement via quantum walks in quantum dots

Science.gov (United States)

Melnikov, Alexey A.; Fedichkin, Leonid E.

2018-02-01

Quantum walks are fundamentally different from random walks due to the quantum superposition property of quantum objects. Quantum walk process was found to be very useful for quantum information and quantum computation applications. In this paper we demonstrate how to use quantum walks as a tool to generate high-dimensional two-particle fermionic entanglement. The generated entanglement can survive longer in the presence of depolorazing noise due to the periodicity of quantum walk dynamics. The possibility to create two distinguishable qudits in a system of tunnel-coupled semiconductor quantum dots is discussed.

Combined sensing platform for advanced diagnostics in exhaled mouse breath

Science.gov (United States)

Fortes, Paula R.; Wilk, Andreas; Seichter, Felicia; Cajlakovic, Merima; Koestler, Stefan; Ribitsch, Volker; Wachter, Ulrich; Vogt, Josef; Radermacher, Peter; Carter, Chance; Raimundo, Ivo M.; Mizaikoff, Boris

2013-03-01

Breath analysis is an attractive non-invasive strategy for early disease recognition or diagnosis, and for therapeutic progression monitoring, as quantitative compositional analysis of breath can be related to biomarker panels provided by a specific physiological condition invoked by e.g., pulmonary diseases, lung cancer, breast cancer, and others. As exhaled breath contains comprehensive information on e.g., the metabolic state, and since in particular volatile organic constituents (VOCs) in exhaled breath may be indicative of certain disease states, analytical techniques for advanced breath diagnostics should be capable of sufficient molecular discrimination and quantification of constituents at ppm-ppb - or even lower - concentration levels. While individual analytical techniques such as e.g., mid-infrared spectroscopy may provide access to a range of relevant molecules, some IR-inactive constituents require the combination of IR sensing schemes with orthogonal analytical tools for extended molecular coverage. Combining mid-infrared hollow waveguides (HWGs) with luminescence sensors (LS) appears particularly attractive, as these complementary analytical techniques allow to simultaneously analyze total CO2 (via luminescence), the 12CO2/13CO2 tracer-to-tracee (TTR) ratio (via IR), selected VOCs (via IR) and O2 (via luminescence) in exhaled breath, yet, establishing a single diagnostic platform as both sensors simultaneously interact with the same breath sample volume. In the present study, we take advantage of a particularly compact (shoebox-size) FTIR spectrometer combined with novel substrate-integrated hollow waveguide (iHWG) recently developed by our research team, and miniaturized fiberoptic luminescence sensors for establishing a multi-constituent breath analysis tool that is ideally compatible with mouse intensive care stations (MICU). Given the low tidal volume and flow of exhaled mouse breath, the TTR is usually determined after sample collection via gas

Cardiovascular Responses Associated with Daily Walking in Subacute Stroke

Directory of Open Access Journals (Sweden)

Sanjay K. Prajapati

2013-01-01

Full Text Available Despite the importance of regaining independent ambulation after stroke, the amount of daily walking completed during in-patient rehabilitation is low. The purpose of this study is to determine if (1 walking-related heart rate responses reached the minimum intensity necessary for therapeutic aerobic exercise (40%–60% heart rate reserve or (2 heart rate responses during bouts of walking revealed excessive workload that may limit walking (>80% heart rate reserve. Eight individuals with subacute stroke attending in-patient rehabilitation were recruited. Participants wore heart rate monitors and accelerometers during a typical rehabilitation day. Walking-related changes in heart rate and walking bout duration were determined. Patients did not meet the minimum cumulative requirements of walking intensity (>40% heart rate reserve and duration (>10 minutes continuously necessary for cardiorespiratory benefit. Only one patient exceeded 80% heart rate reserve. The absence of significant increases in heart rate associated with walking reveals that patients chose to walk at speeds well below a level that has meaningful cardiorespiratory health benefits. Additionally, cardiorespiratory workload is unlikely to limit participation in walking. Measurement of heart rate and walking during in-patient rehabilitation may be a useful approach to encourage patients to increase the overall physical activity and to help facilitate recovery.

Transit-Related Walking to Work in Promoting Physical Activity.

Science.gov (United States)

Yu, Chia-Yuan; Lin, Hsien-Chang

2015-04-01

Transit-related walking to work is a potential strategy for incorporating physical activity into daily life and promoting health benefits. This study estimated the transit-related walking time for work trips on the journey to and from work and examined the predictors of transit users who walked to/from transit and the workplace and those who walked 30 minutes or more per day. This study used the 2009 National Household Travel Survey and identified 772 subjects who took transit to/from work, 355 subjects who walked to/from transit and the workplace, and 145 subjects who walked 30 minutes or more per day among the 40,659 workers. Weighted logistic regressions were used for the analysis. Of the people who walked to/from transit and the workplace, 40.9% walked 30 minutes or more per day. The weighted logistic regressions revealed that low-income groups and workers living in high population density areas were more likely to walk to/from transit and the workplace. Workers living in high population density areas were more likely to walk 30 minutes or more per day. Transit-related walking to work provides an opportunity to increase physical activity levels and to meet the physical activity recommendations.

14C-urea breath test for the detection of Helicobacter pylori

NARCIS (Netherlands)

Veldhuyzen van Zanten, S. J.; Tytgat, K. M.; Hollingsworth, J.; Jalali, S.; Rshid, F. A.; Bowen, B. M.; Goldie, J.; Goodacre, R. L.; Riddell, R. H.; Hunt, R. H.

1990-01-01

The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14C-urea breath test which uses 5 microCi 14C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared

Influence of neuromuscular noise and walking speed on fall risk and dynamic stability in a 3D dynamic walking model.

Science.gov (United States)

Roos, Paulien E; Dingwell, Jonathan B

2013-06-21

Older adults and those with increased fall risk tend to walk slower. They may do this voluntarily to reduce their fall risk. However, both slower and faster walking speeds can predict increased risk of different types of falls. The mechanisms that contribute to fall risk across speeds are not well known. Faster walking requires greater forward propulsion, generated by larger muscle forces. However, greater muscle activation induces increased signal-dependent neuromuscular noise. These speed-related increases in neuromuscular noise may contribute to the increased fall risk observed at faster walking speeds. Using a 3D dynamic walking model, we systematically varied walking speed without and with physiologically-appropriate neuromuscular noise. We quantified how actual fall risk changed with gait speed, how neuromuscular noise affected speed-related changes in fall risk, and how well orbital and local dynamic stability measures predicted changes in fall risk across speeds. When we included physiologically-appropriate noise to the 'push-off' force in our model, fall risk increased with increasing walking speed. Changes in kinematic variability, orbital, and local dynamic stability did not predict these speed-related changes in fall risk. Thus, the increased neuromuscular variability that results from increased signal-dependent noise that is necessitated by the greater muscular force requirements of faster walking may contribute to the increased fall risk observed at faster walking speeds. The lower fall risk observed at slower speeds supports experimental evidence that slowing down can be an effective strategy to reduce fall risk. This may help explain the slower walking speeds observed in older adults and others. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of influenza vaccination on oxidative stress products in breath.

Science.gov (United States)

Phillips, Michael; Cataneo, Renee N; Chaturvedi, Anirudh; Danaher, Patrick J; Devadiga, Anantrai; Legendre, David A; Nail, Kim L; Schmitt, Peter; Wai, James

2010-06-01

Viral infections cause increased oxidative stress, so a breath test for oxidative stress biomarkers (alkanes and alkane derivatives) might provide a new tool for early diagnosis. We studied 33 normal healthy human subjects receiving scheduled treatment with live attenuated influenza vaccine (LAIV). Each subject was his or her own control, since they were studied on day 0 prior to vaccination, and then on days 2, 7 and 14 following vaccination. Breath volatile organic compounds (VOCs) were collected with a breath collection apparatus, then analyzed by automated thermal desorption with gas chromatography and mass spectroscopy. A Monte Carlo simulation technique identified non-random VOC biomarkers of infection based on their C-statistic values (area under curve of receiver operating characteristic). Treatment with LAIV was followed by non-random changes in the abundance of breath VOCs. 2, 8-Dimethyl-undecane and other alkane derivatives were observed on all days. Conservative multivariate models identified vaccinated subjects on day 2 (C-statistic = 0.82, sensitivity = 63.6% and specificity = 88.5%); day 7 (C-statistic = 0.94, sensitivity = 88.5% and specificity = 92.3%); and day 14 (C-statistic = 0.95, sensitivity = 92.3% and specificity = 92.3%). The altered breath VOCs were not detected in live attenuated influenza vaccine, excluding artifactual contamination. LAIV vaccination in healthy humans elicited a prompt and sustained increase in breath biomarkers of oxidative stress. A breath test for these VOCs could potentially identify humans who are acutely infected with influenza, but who have not yet developed clinical symptoms or signs of disease.

Breath tests and irritable bowel syndrome.

Science.gov (United States)

Rana, Satya Vati; Malik, Aastha

2014-06-28

Breath tests are non-invasive tests and can detect H₂ and CH₄ gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H₂ breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients.

Self-avoiding polygons and walks in slits

International Nuclear Information System (INIS)

Alvarez, J; Whittington, S G; Rensburg, E J Janse van; Soteros, C E

2008-01-01

A polymer in a confined geometry may be modeled by a self-avoiding walk or a self-avoiding polygon confined between two parallel walls. In two dimensions, this model involves self-avoiding walks or self-avoiding polygons in the square lattice between two parallel confining lines. Interactions of the polymer with the confining walls are introduced by energy terms associated with edges in the walk or polygon which are at or near the confining lines. We use transfer-matrix methods to investigate the forces between the walk or polygon and the confining lines, as well as to investigate the effects of the confining slit's width and of the energy terms on the thermodynamic properties of the walks or polygons in several models. The phase diagram found for the self-avoiding walk models is qualitatively similar to the phase diagram of a directed walk model confined between two parallel lines, as was previously conjectured. However, the phase diagram of one of our polygon models is found to be significantly different and we present numerical data to support this. For that particular model we prove that, for any finite values of the energy terms, there are an infinite number of slit widths where a polygon will induce a steric repulsion between the confining lines

1,001 words and phrases you never knew you didn't know hopperdozer, hoecake, ear trumpet, dort, and other nearly forgotten terms and expressions

CERN Document Server

Runyan, W R

2010-01-01

As times change so do the things we use and what we call them. W.R. Runyan has compiled a fascinating collection of words and phrases that, once common everywhere in America, are little known today. This book is a celebration of our linguistic past that will be a treat from word lovers everywhere. Do you know any of these: Snaffle, Steelie, Gully Washer, Cabriolet, Calk, Hardpan, Carbuncle, Pie Bird, Fid, or Hame? Did you know that a "Horse Apple" is actually an orange? Or that "Rolley Holley" is a marble game? With over one hundred illustrations, this is a book that will take you on a walk back in time and give you a chance to hear from generations past-in their own voice, with their own words.

Know-how and nuclear exports

International Nuclear Information System (INIS)

Luxo, A.

1978-01-01

The concrete content of nuclear know-how is defined, and the present position as to the exchange of know-how is discussed. The new forms which may be taken by this know-how are considered and the results which may be expected from a know-how transfer (both for the exporting and the importing countries) are related [fr

Medication effects on sleep and breathing.

Science.gov (United States)

Seda, Gilbert; Tsai, Sheila; Lee-Chiong, Teofilo

2014-09-01

Sleep respiration is regulated by circadian, endocrine, mechanical and chemical factors, and characterized by diminished ventilatory drive and changes in Pao2 and Paco2 thresholds. Hypoxemia and hypercapnia are more pronounced during rapid eye movement. Breathing is influenced by sleep stage and airway muscle tone. Patient factors include medical comorbidities and body habitus. Medications partially improve obstructive sleep apnea and stabilize periodic breathing at altitude. Potential adverse consequences of medications include precipitation or worsening of disorders. Risk factors for adverse medication effects include aging, medical disorders, and use of multiple medications that affect respiration. Published by Elsevier Inc.

The effects of metronome breathing on the variability of autonomic activity measurements.

Science.gov (United States)

Driscoll, D; Dicicco, G

2000-01-01

Many chiropractors hypothesize that spinal manipulation affects the autonomic nervous system (ANS). However, the ANS responses to chiropractic manipulative therapy are not well documented, and more research is needed to support this hypothesis. This study represents a step toward the development of a reliable method by which to document that chiropractic manipulative therapy does affect the ANS by exploring the use of paced breathing as a way to reduce the inherent variability in ANS measurements. To examine the hypothesis that the variability of ANS measurements would be reduced if breathing were paced to a metronome at 12 breaths/min. The study was performed at Parker College Research Institute. Eight normotensive subjects were recruited from the student body and staff. Respiration frequency was measured through a strain gauge. A 3-lead electrocardiogram (ECG) was used to register the electric activity of the heart, and arterial tonometry monitors were used to record the left and right radial artery blood pressures. Signals were recorded on an IBM-compatible computer with a sampling frequency of 100 Hz. Normal breathing was used for the first 3 recordings, and breathing was paced to a metronome for the final 3 recordings at 12 breaths/min. Fourier analysis was performed on the beat-by-beat fluctuations of the ECG-determined R-R interval and systolic arterial pressure (SBP). Low-frequency fluctuations (LF; 0.04-0.15 Hz) reflected sympathetic activity, whereas high-frequency fluctuations (HF; 0.15-0.4 Hz) represented parasympathetic activity. Sympathovagal indices were determined from the ratio of the two bandwidths (LF/HF). The coefficient of variation (CV%) for autonomic parameters was calculated ([average/SD] x 100%) to compare breathing normally and breathing to a metronome with respect to variability. One-way analysis of variance was used to detect differences. A value of P Metronome breathing did not produce any significant changes in blood pressure for the

Symptoms of Sleep Disordered Breathing and Risk of Cancer

DEFF Research Database (Denmark)

Christensen, Anne Sofie; Clark, Alice; Salo, Paula

2013-01-01

Sleep disordered breathing (SDB) has been associated with oxidative stress, inflammation, and altered hormonal levels, all of which could affect the risk of cancer. The aim of the study is to examine if symptoms of SDB including snoring, breathing cessations, and daytime sleepiness affect...

The moving platform after-effect reveals dissociation between what we know and how we walk.

Science.gov (United States)

Reynolds, R; Bronstein, A

2007-01-01

Gait adaptation is crucial for coping with varying terrain and biological needs. It is also important that any acquired adaptation is expressed only in the appropriate context. Here we review a recent series of experiments which demonstrate inappropriate expression of gait adaptation. We showed that a brief period of walking onto a platform previously experienced as moving results in a large forward sway despite full awareness of the changing context. The adaptation mechanisms involved in this paradigm are extremely fast, just 1-2 discrete exposures to the moving platform results in a motor after-effect. This after-effect still occurs even if subjects deliberately attempt to suppress it. However it disappears when the location or method of gait is altered, indicating that after-effect expression is context dependent. Conversely, making gait self-initiated increased sway during the after-effect. This after-effect demonstrates a profound dissociation between knowledge and action. The absence of generalisation suggests a simple form of motor learning. However, persistent expression of gait after-effects may be dependent on an intact cerebral cortex. The fact that the after-effect is greater during self-initiated gait, and is context dependent, would be consistent with the involvement of supraspinal areas.

Ventilatory and Cardiovascular Regulation in the Air-Breathing Fish Pangasianodon Hypophthalmus

DEFF Research Database (Denmark)

Thomsen, Mikkel; Wang, Tobias; Bayley, Mark

The air-breathing fish Pangasianodon hypophthalmus is abundant in the Mekong river system where it is also intensively cultured. In contrast to most other air-breathing fishes it has well developed gills as well as a highly traberculated swim bladder with a large surface area used for air-breathing...... systems provide information on when gill ventilation is insufficient for oxygen uptake and hence initiate air-breathing. Here we investigate the ventilatory and cardiovascular responses to changes in either in the external media or internally in the blood in resting fish. We found ventilation in P....... Its native waters have been shown to be periodically strongly hypoxic and hypercarbic, forcing P. hypophthalmus to switch from exclusively branchial ventilation to air-breathing to maintain its aerobic metabolism. This ability to switch respiratory media demands that the oxygen- and CO¬2 sensory...

'Pedometers cost buttons': the feasibility of implementing a pedometer based walking programme within the community

Directory of Open Access Journals (Sweden)

Fitzsimons Claire

2011-03-01

Full Text Available Abstract Background Recent studies have suggested that walking interventions may be effective (at least in the short term at increasing physical activity amongst those people who are the most inactive. This is a leading objective of contemporary public health policy in the UK and worldwide. However, before committing money from limited budgets to implement walking interventions more widely in the community, policymakers will want to know whether similar impacts can be expected and whether any changes will be required to the process to ensure uptake and success. This paper utilises the findings from a recent community-based pedometer study (Walking for Wellbeing in the West - WWW undertaken in Glasgow, Scotland to address issues of feasibility. Methods An economic analysis of the WWW study assessed the costs of the interventions (minimal and maximal and combined these with the effects to present incremental cost-effectiveness ratios (cost/person achieving the target of an additional 15,000 steps/week. A qualitative evaluation, involving focus group discussions with WWW participants and short interviews with members of the WWW research team, explored perceived benefits and barriers associated with walking, as well as the successful aspects and challenges associated with the interventions. Results The incremental cost effectiveness associated with the interventions was estimated as £92 and £591 per person achieving the target for the minimal and maximal interventions respectively. The qualitative evaluation gave insight into the process by which the results were achieved, and identified several barriers and facilitators that would need to be addressed before implementing the interventions in the wider community, in order to ensure their effective transfer. These included assessing the impact of the relationship between researchers and participants on the results, and the motivational importance of monitoring and assessing performance. Conclusions

Distracted walking: Examining the extent to pedestrian safety problems

Directory of Open Access Journals (Sweden)

Judith Mwakalonge

2015-10-01

Full Text Available Pedestrians, much like drivers, have always been engaged in multi-tasking like using hand-held devices, listening to music, snacking, or reading while walking. The effects are similar to those experienced by distracted drivers. However, distracted walking has not received similar policies and effective interventions as distracted driving to improve pedestrian safety. This study reviewed the state-of-practice on policies, campaigns, available data, identified research needs, and opportunities pertaining to distracted walking. A comprehensive review of literature revealed that some of the agencies/organizations disseminate useful information about certain distracting activities that pedestrians should avoid while walking to improve their safety. Various walking safety rules/tips have been given, such as not wearing headphones or talking on a cell phone while crossing a street, keeping the volume down, hanging up the phone while walking, being aware of traffic, and avoiding distractions like walking with texting. The majority of the past observational-based and experimental-based studies reviewed in this study on distracted walking is in agreement that there is a positive correlation between distraction and unsafe walking behavior. However, limitations of the existing crash data suggest that distracted walking may not be a severe threat to the public health. Current pedestrian crash data provide insufficient information for researchers to examine the extent to which distracted walking causes and/or contributes to actual pedestrian safety problems.

I Walk My Dog Because It Makes Me Happy: A Qualitative Study to Understand Why Dogs Motivate Walking and Improved Health.

Science.gov (United States)

Westgarth, Carri; Christley, Robert M; Marvin, Garry; Perkins, Elizabeth

2017-08-19

Dog walking is a popular everyday physical activity. Dog owners are generally more active than non-owners, but some rarely walk with their dog. The strength of the dog-owner relationship is known to be correlated with dog walking, and this qualitative study investigates why. Twenty-six interviews were combined with autoethnography of dog walking experiences. Dog walking was constructed as "for the dog", however, owners represented their dog's needs in a way which aligned with their own. Central to the construction of need was perceptions of dog personality and behaviour. Owners reported deriving positive outcomes from dog walking, most notably, feelings of "happiness", but these were "contingent" on the perception that their dogs were enjoying the experience. Owner physical activity and social interaction were secondary bonuses but rarely motivating. Perceptions and beliefs of owners about dog walking were continually negotiated, depending on how the needs of the owner and dog were constructed at that time. Complex social interactions with the "significant other" of a pet can strongly motivate human health behaviour. Potential interventions to promote dog walking need to account for this complexity and the effect of the dog-owner relationship on owner mental wellbeing.

Air-breathing fishes in aquaculture. What can we learn from physiology?

Science.gov (United States)

Lefevre, S; Wang, T; Jensen, A; Cong, N V; Huong, D T T; Phuong, N T; Bayley, M

2014-03-01

During the past decade, the culture of air-breathing fish species has increased dramatically and is now a significant global source of protein for human consumption. This development has generated a need for specific information on how to maximize growth and minimize the environmental effect of culture systems. Here, the existing data on metabolism in air-breathing fishes are reviewed, with the aim of shedding new light on the oxygen requirements of air-breathing fishes in aquaculture, reaching the conclusion that aquatic oxygenation is much more important than previously assumed. In addition, the possible effects on growth of the recurrent exposure to deep hypoxia and associated elevated concentrations of carbon dioxide, ammonia and nitrite, that occurs in the culture ponds used for air-breathing fishes, are discussed. Where data on air-breathing fishes are simply lacking, data for a few water-breathing species will be reviewed, to put the physiological effects into a growth perspective. It is argued that an understanding of air-breathing fishes' respiratory physiology, including metabolic rate, partitioning of oxygen uptake from air and water in facultative air breathers, the critical oxygen tension, can provide important input for the optimization of culture practices. Given the growing importance of air breathers in aquaculture production, there is an urgent need for further data on these issues. © 2014 The Fisheries Society of the British Isles.

Features of motivation of the crewmembers in an enclosed space at atmospheric pressure changes during breathing inert gases.

Science.gov (United States)

Komarevcev, Sergey

Since the 1960s, our psychologists are working on experimenting with small groups in isolation .It was associated with the beginning of spaceflight and necessity to study of human behaviors in ways different from the natural habitat of man .Those, who study human behavior especially in isolation, know- that the behavior in isolation markedly different from that in the natural situations. It associated with the development of new, more adaptive behaviors (1) What are the differences ? First of all , isolation is achieved by the fact ,that the group is in a closed space. How experiments show - the crew members have changed the basic personality traits, such as motivation Statement of the problem and methods. In our experimentation we were interested in changing the features of human motivation (strength, stability and direction of motivation) in terms of a closed group in the modified atmosphere pressure and breathing inert gases. Also, we were interested in particular external and internal motivation of the individual in the circumstances. To conduct experimentation , we used an experimental barocomplex GVK -250 , which placed a group of six mans. A task was to spend fifteen days in isolation on barokomplex when breathing oxigen - xenon mixture of fifteen days in isolation on the same complex when breathing oxygen- helium mixture and fifteen days of isolation on the same complex when breathing normal air All this time, the subjects were isolated under conditions of atmospheric pressure changes , closer to what you normally deal divers. We assumed that breathing inert mixtures can change the strength and stability , and with it , the direction and stability of motivation. To check our results, we planned on using the battery of psychological techniques : 1. Schwartz technique that measures personal values and behavior in society, DORS procedure ( measurement of fatigue , monotony , satiety and stress ) and riffs that give the test once a week. Our assumption is

Detection of bronchial breathing caused by pneumonia.

Science.gov (United States)

Gross, V; Fachinger, P; Penzel, Th; Koehler, U; von Wichert, P; Vogelmeier, C

2002-06-01

The classic auscultation with stethoscope is the established clinical method for the detection of lung diseases. The interpretation of the sounds depends on the experience of the investigating physician. Therefore, a new computer-based method has been developed to classify breath sounds from digital lung sound recordings. Lung sounds of 11 patients with one-sided pneumonia and bronchial breathing were recorded on both the pneumonia side and on contralateral healthy side simultaneously using two microphones. The spectral power for the 300-600 Hz frequency band was computed for four respiratory cycles and normalized. For each breath, the ratio R between the time-segments (duration = 0.1 s) with the highest inspiratory and highest expiratory flow was calculated and averaged. We found significant differences in R between the pneumonia side (R = 1.4 +/- 1.3) and the healthy side (R = 0.5 +/- 0.5; p = 0.003 Wilcoxon-test) of lung. In 218 healthy volunteers we found R = 0.3 +/- 0.2 as a reference-value. The differences of ratio R (delta R) between the pneumonia side and the healthy side (delta R = 1.0 +/- 0.9) were significantly higher compared to follow-up studies after recovery (delta R = 0.0 +/- 0.1, p = 0.005 Wilcoxon-test). The computer based detection of bronchial breathing can be considered useful as part of a quantitative monitoring of patients at risk to develop pneumonia.

Measurement and prediction of indoor air quality using a breathing thermal manikin

DEFF Research Database (Denmark)

Melikov, Arsen Krikor; Kaczmarczyk, J.

2007-01-01

temperature is sensitive enough to perform reliable measurement of characteristics of air as inhaled by occupants. The temperature, humidity, and pollution concentration in the inhaled air can be measured accurately with a thermal manikin without breathing simulation if they are measured at the upper lip...... at a distance of measured inhaled air parameters. Proper simulation of breathing, especially of exhalation, is needed for studying the transport of exhaled air between occupants. A method......The analyses performed in this paper reveal that a breathing thermal manikin with realistic simulation of respiration including breathing cycle, pulmonary ventilation rate, frequency and breathing mode, gas concentration, humidity and temperature of exhaled air and human body shape and surface...

Running for exercise mitigates age-related deterioration of walking economy.

Directory of Open Access Journals (Sweden)

Justus D Ortega

Full Text Available Impaired walking performance is a key predictor of morbidity among older adults. A distinctive characteristic of impaired walking performance among older adults is a greater metabolic cost (worse economy compared to young adults. However, older adults who consistently run have been shown to retain a similar running economy as young runners. Unfortunately, those running studies did not measure the metabolic cost of walking. Thus, it is unclear if running exercise can prevent the deterioration of walking economy.To determine if and how regular walking vs. running exercise affects the economy of locomotion in older adults.15 older adults (69 ± 3 years who walk ≥ 30 min, 3x/week for exercise, "walkers" and 15 older adults (69 ± 5 years who run ≥ 30 min, 3x/week, "runners" walked on a force-instrumented treadmill at three speeds (0.75, 1.25, and 1.75 m/s. We determined walking economy using expired gas analysis and walking mechanics via ground reaction forces during the last 2 minutes of each 5 minute trial. We compared walking economy between the two groups and to non-aerobically trained young and older adults from a prior study.Older runners had a 7-10% better walking economy than older walkers over the range of speeds tested (p = .016 and had walking economy similar to young sedentary adults over a similar range of speeds (p =  .237. We found no substantial biomechanical differences between older walkers and runners. In contrast to older runners, older walkers had similar walking economy as older sedentary adults (p =  .461 and ∼ 26% worse walking economy than young adults (p<.0001.Running mitigates the age-related deterioration of walking economy whereas walking for exercise appears to have minimal effect on the age-related deterioration in walking economy.

Fast-starting after a breath: air-breathing motions are kinematically similar to escape responses in the catfish Hoplosternum littorale

Directory of Open Access Journals (Sweden)

Paolo Domenici

2014-12-01

Full Text Available Fast-starts are brief accelerations commonly observed in fish within the context of predator–prey interactions. In typical C-start escape responses, fish react to a threatening stimulus by bending their body into a C-shape during the first muscle contraction (i.e. stage 1 which provides a sudden acceleration away from the stimulus. Recently, similar C-starts have been recorded in fish aiming at a prey. Little is known about C-starts outside the context of predator–prey interactions, though recent work has shown that escape response can also be induced by high temperature. Here, we test the hypothesis that air-breathing fish may use C-starts in the context of gulping air at the surface. Hoplosternum littorale is an air-breathing freshwater catfish found in South America. Field video observations reveal that their air-breathing behaviour consists of air-gulping at the surface, followed by a fast turn which re-directs the fish towards the bottom. Using high-speed video in the laboratory, we compared the kinematics of the turn immediately following air-gulping performed by H. littorale in normoxia with those of mechanically-triggered C-start escape responses and with routine (i.e. spontaneous turns. Our results show that air-breathing events overlap considerably with escape responses with a large stage 1 angle in terms of turning rates, distance covered and the relationship between these rates. Therefore, these two behaviours can be considered kinematically comparable, suggesting that air-breathing in this species is followed by escape-like C-start motions, presumably to minimise time at the surface and exposure to avian predators. These findings show that C-starts can occur in a variety of contexts in which fish may need to get away from areas of potential danger.

[Walking abnormalities in children].

Science.gov (United States)

Segawa, Masaya

2010-11-01

Walking is a spontaneous movement termed locomotion that is promoted by activation of antigravity muscles by serotonergic (5HT) neurons. Development of antigravity activity follows 3 developmental epochs of the sleep-wake (S-W) cycle and is modulated by particular 5HT neurons in each epoch. Activation of antigravity activities occurs in the first epoch (around the age of 3 to 4 months) as restriction of atonia in rapid eye movement (REM) stage and development of circadian S-W cycle. These activities strengthen in the second epoch, with modulation of day-time sleep and induction of crawling around the age of 8 months and induction of walking by 1 year. Around the age of 1 year 6 months, absence of guarded walking and interlimb cordination is observed along with modulation of day-time sleep to once in the afternoon. Bipedal walking in upright position occurs in the third epoch, with development of a biphasic S-W cycle by the age of 4-5 years. Patients with infantile autism (IA), Rett syndrome (RTT), or Tourette syndrome (TS) show failure in the development of the first, second, or third epoch, respectively. Patients with IA fail to develop interlimb coordination; those with RTT, crawling and walking; and those with TS, walking in upright posture. Basic pathophysiology underlying these condition is failure in restricting atonia in REM stage; this induces dysfunction of the pedunculopontine nucleus and consequently dys- or hypofunction of the dopamine (DA) neurons. DA hypofunction in the developing brain, associated with compensatory upward regulation of the DA receptors causes psychobehavioral disorders in infancy (IA), failure in synaptogenesis in the frontal cortex and functional development of the motor and associate cortexes in late infancy through the basal ganglia (RTT), and failure in functional development of the prefrontal cortex through the basal ganglia (TS). Further, locomotion failure in early childhood causes failure in development of functional

Audio-haptic interaction in simulated walking experiences

DEFF Research Database (Denmark)

Serafin, Stefania

2011-01-01

and interchangeable use of the haptic and auditory modality in floor interfaces, and for the synergy of perception and action in capturing and guiding human walking. We describe the technology developed in the context of this project, together with some experiments performed to evaluate the role of auditory......In this paper an overview of the work conducted on audio-haptic physically based simulation and evaluation of walking is provided. This work has been performed in the context of the Natural Interactive Walking (NIW) project, whose goal is to investigate possibilities for the integrated...... and haptic feedback in walking tasks....

Breathing difficulty - lying down

Science.gov (United States)

... other conditions that lead to it) Panic disorder Sleep apnea Snoring Home Care Your health care provider may recommend self-care measures. For example, weight loss may be suggested if you are obese. When to Contact a Medical Professional If you have any unexplained difficulty in breathing ...

A case study of energy expenditure based on walking speed reduction during walking upstairs situation at a staircase in FKAAS, UTHM, Johor building

Science.gov (United States)

Abustan, M. S.; Ali, M. F. M.; Talib, S. H. A.

2018-04-01

Walking velocity is a vector quantity that can be determined by calculating the time taken and displacement of a moving objects. In Malaysia, there are very few researches that were done to determine the walking velocity of citizens to be compared with other countries such as the study about walking upstairs during evacuation process is important when emergency case happen, if there are people in underground garages, they have to walk upstairs for exits and look for shelter and the walking velocity of pedestrian in such cases are necessary to be analysed. Therefore, the objective of this study is to determine the walking speed of pedestrian during walking upstairs situation, finding the relationship between pedestrian walking speed and the characteristics of the pedestrian as well as analysing the energy reduction by comparing the walking speed of pedestrian at the beginning and at the end of staircase. In this case study, an experiment was done to determine the average walking speed of pedestrian. The pedestrian has been selected from different gender, physical character, and age. Based on the data collected, the average normal walking speed of male pedestrian was 1.03 m/s while female was 1.08 m/s. During walking upstairs, the walking speed of pedestrian decreased as the number of floor increased. The average speed for the first stairwell was 0.90 m/s and the number decreased to 0.73 m/s for the second stairwell. From the reduction of speed, the energy used has been calculated and the average kinetic energy used was 1.69 J. Hence, the data collected can be used for further research of staircase design and plan of evacuation process.

Walking Tips for Older Adults

Science.gov (United States)

... you can continue your walking program. Don’t let a cane or walker stop you It’s OK to use your cane or walker if you already have one. These can improve your balance and help take the load off painful joints. Aim for the right pace Try to walk as fast as you ...

Design of wheel-type walking-assist device

International Nuclear Information System (INIS)

Jung, Seung Ho; Kim, Seung Ho; Kim, Chang Hoi; Seo, Yong Chil; Jung, Kyung Min; Lee, Sung Uk

2006-03-01

In this research, a outdoor wheel-type walking-assist device is developed to help an elder having a poor muscular strength at legs for walking, sitting and standing up easily at outdoors, and also for going and downing stairs. In conceptually designing, the environments of an elder's activity, the size of an elder's body and a necessary function of helping an elder are considered. This device has 4 wheels for stability. When an elder walks in incline plane with the proposed device, a rear-wing is rotated to keep the supporting device horizontal, regardless of an angle of inclination. A height-controlling device, which can control the height of the supporting device for adjusting an elder's height, is varied vertically to help an elder to sit and stand-up easily. Moreover, a outdoor wheel-type walking-assist device is conceptually designed and is made. In order to design it, the preview research is investigated firstly. On the basis of the proposed walking-assist device, the outdoor walking-assist device is designed and made. The outdoor wheel-type walking-assist device can go and down stairs automatically. This device go up and down the stair of having maximum 20cm height and an angle of 25 degrees with maximum 4 sec/stairs speed, and move at flatland with 60cm/sec speed

Searching via walking: How to find a marked clique of a complete graph using quantum walks

International Nuclear Information System (INIS)

Hillery, Mark; Reitzner, Daniel; Buzek, Vladimir

2010-01-01

We show how a quantum walk can be used to find a marked edge or a marked complete subgraph of a complete graph. We employ a version of a quantum walk, the scattering walk, which lends itself to experimental implementation. The edges are marked by adding elements to them that impart a specific phase shift to the particle as it enters or leaves the edge. If the complete graph has N vertices and the subgraph has K vertices, the particle becomes localized on the subgraph in O(N/K) steps. This leads to a quantum search that is quadratically faster than a corresponding classical search. We show how to implement the quantum walk using a quantum circuit and a quantum oracle, which allows us to specify the resources needed for a quantitative comparison of the efficiency of classical and quantum searches--the number of oracle calls.

Ways of Walking

DEFF Research Database (Denmark)

Eslambolchilar, Parisa; Bødker, Mads; Chamberlain, Alan

2016-01-01

It seems logical to argue that mobile computing technologies are intended for use "on-the-go." However, on closer inspection, the use of mobile technologies pose a number of challenges for users who are mobile, particularly moving around on foot. In engaging with such mobile technologies and thei......It seems logical to argue that mobile computing technologies are intended for use "on-the-go." However, on closer inspection, the use of mobile technologies pose a number of challenges for users who are mobile, particularly moving around on foot. In engaging with such mobile technologies...... and their envisaged development, we argue that interaction designers must increasingly consider a multitude of perspectives that relate to walking in order to frame design problems appropriately. In this paper, we consider a number of perspectives on walking, and we discuss how these may inspire the design of mobile...... technologies. Drawing on insights from non-representational theory, we develop a partial vocabulary with which to engage with qualities of pedestrian mobility, and we outline how taking more mindful approaches to walking may enrich and inform the design space of handheld technologies....

Can environmental improvement change the population distribution of walking?

Science.gov (United States)

Panter, Jenna; Ogilvie, David

2017-06-01

Few studies have explored the impact of environmental change on walking using controlled comparisons. Even fewer have examined whose behaviour changes and how. In a natural experimental study of new walking and cycling infrastructure, we explored changes in walking, identified groups who changed in similar ways and assessed whether exposure to the infrastructure was associated with trajectories of walking. 1257 adults completed annual surveys assessing walking, sociodemographic and health characteristics and use of the infrastructure (2010-2012). Residential proximity to the new routes was assessed objectively. We used latent growth curve models to assess change in total walking, walking for recreation and for transport, used simple descriptive analysis and latent class analysis (LCA) to identify groups who changed in similar ways and examined factors associated with group membership using multinomial regression. LCA identified five trajectories, characterised by consistently low levels; consistently high levels; decreases; short-lived increases; and sustained increases. Those with lower levels of education and lower incomes were more likely to show both short-lived and sustained increases in walking for transport. However, those with lower levels of education were less likely to take up walking. Proximity to the intervention was associated with both uptake of and short-lived increases in walking for transport. Environmental improvement encouraged the less active to take up walking for transport, as well as encouraging those who were already active to walk more. Further research should disentangle the role of socioeconomic characteristics in determining use of new environments and changes in walking. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Analytical methodologies for broad metabolite coverage of exhaled breath condensate.

Science.gov (United States)

Aksenov, Alexander A; Zamuruyev, Konstantin O; Pasamontes, Alberto; Brown, Joshua F; Schivo, Michael; Foutouhi, Soraya; Weimer, Bart C; Kenyon, Nicholas J; Davis, Cristina E

2017-09-01

Breath analysis has been gaining popularity as a non-invasive technique that is amenable to a broad range of medical uses. One of the persistent problems hampering the wide application of the breath analysis method is measurement variability of metabolite abundances stemming from differences in both sampling and analysis methodologies used in various studies. Mass spectrometry has been a method of choice for comprehensive metabolomic analysis. For the first time in the present study, we juxtapose the most commonly employed mass spectrometry-based analysis methodologies and directly compare the resultant coverages of detected compounds in exhaled breath condensate in order to guide methodology choices for exhaled breath condensate analysis studies. Four methods were explored to broaden the range of measured compounds across both the volatile and non-volatile domain. Liquid phase sampling with polyacrylate Solid-Phase MicroExtraction fiber, liquid phase extraction with a polydimethylsiloxane patch, and headspace sampling using Carboxen/Polydimethylsiloxane Solid-Phase MicroExtraction (SPME) followed by gas chromatography mass spectrometry were tested for the analysis of volatile fraction. Hydrophilic interaction liquid chromatography and reversed-phase chromatography high performance liquid chromatography mass spectrometry were used for analysis of non-volatile fraction. We found that liquid phase breath condensate extraction was notably superior compared to headspace extraction and differences in employed sorbents manifested altered metabolite coverages. The most pronounced effect was substantially enhanced metabolite capture for larger, higher-boiling compounds using polyacrylate SPME liquid phase sampling. The analysis of the non-volatile fraction of breath condensate by hydrophilic and reverse phase high performance liquid chromatography mass spectrometry indicated orthogonal metabolite coverage by these chromatography modes. We found that the metabolite coverage

Hypotensive response after water-walking and land-walking exercise sessions in healthy trained and untrained women

Directory of Open Access Journals (Sweden)

Bocalini DS

2011-08-01

Full Text Available Daniel Rodriguez1, Valter Silva2, Jonato Prestes3, Roberta Luksevicius Rica4, Andrey Jorge Serra5, Danilo Sales Bocalini6, Francisco Luciano Pontes Junior71São Judas Tadeu University, São Paulo, SP, Brazil; 2College of Physical Education of Sorocaba, Sorocaba, SP, Brazil; 3Graduation Program in Physical Education, Catholic University of Brasilia, Brasilia-DF, Brazil; 4Department of Physical Education, Arbos College, São Bernardo do Campo, SP, Brazil; 5Department of Physical Education and Laboratory of Rehabilitation Science, Nove de Julho University, São Paulo, SP, Brazil; 6Department of Medicine, Federal University of São Paulo – Escola Paulista de Medicina, São Paulo, SP, Brazil; 7School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, SP, BrazilBackground: The aim of this study was to compare post-exercise hypotension after acute sessions of water-walking and land-walking in healthy trained and untrained women.Methods: Twenty-three untrained (n = 12 and trained (n = 11 normotensive women performed two walking sessions in water and on land at 40% of peak VO2 for 45 minutes. Systolic and diastolic blood pressure and mean arterial pressure were measured 15, 30, 45, and 60 minutes after the exercise sessions.Results: No differences were found between the groups for age and anthropometric parameters, but peak VO2 for the trained women (45 ± 8 mL/kg/minute was higher than for the untrained women (31 ± 3 mL/kg/minute. No differences were found between the groups with regard to systolic and diastolic blood pressure and mean arterial pressure after water immersion. The heart rate in the trained group (62 ± 3 beats per minute [bpm] was significantly lower (P < 0.05 than in the untrained group (72 ± 4 bpm on land, and after water immersion, this difference disappeared (58 ± 5 bpm in the trained women and 66 ± 5 bpm in the untrained women. Sixty minutes after water-walking, systolic blood pressure (108 ± 8 mmHg vs

The breathtaking truth about breath alcohol readings of zero

NARCIS (Netherlands)

Verster, Joris C; Mackus, Marlou; van de Loo, Aurora Jae; Garssen, Johan; Scholey, Andrew

INTRODUCTION: It has been postulated that the hangover state starts when breath alcohol concentration is zero. METHODS: Data from 2 studies that assessed ethanol in breath, blood and urine were compared. RESULTS: The data revealed that ethanol may still be present in the blood and urine during the

How Important Is a Reproducible Breath Hold for Deep Inspiration Breath Hold Breast Radiation Therapy?

International Nuclear Information System (INIS)

Wiant, David; Wentworth, Stacy; Liu, Han; Sintay, Benjamin

2015-01-01

Purpose: Deep inspiration breath hold (DIBH) for left-sided breast cancer has been shown to reduce heart dose. Surface imaging helps to ensure accurate breast positioning, but it does not guarantee a reproducible breath hold (BH) at DIBH treatments. We examine the effects of variable BH positions for DIBH treatments. Methods and Materials: Twenty-five patients who underwent free breathing (FB) and DIBH scans were reviewed. Four plans were created for each patient: FB, DIBH, FB-DIBH (the DIBH plans were copied to the FB images and recalculated, and image registration was based on breast tissue), and P-DIBH (a partial BH with the heart shifted midway between the FB and DIBH positions). The FB-DIBH plans give a “worst-case” scenario for surface imaging DIBH, where the breast is aligned by surface imaging but the patient is not holding their breath. Kolmogorov-Smirnov tests were used to compare the dose metrics. Results: The DIBH plans gave lower heart dose and comparable breast coverage versus FB in all cases. The FB-DIBH plans showed no significant difference versus FB plans for breast coverage, mean heart dose, or maximum heart dose (P≥.10). The mean heart dose differed between FB-DIBH and FB by <2 Gy for all cases, and the maximum heart dose differed by <2 Gy for 21 cases. The P-DIBH plans showed significantly lower mean heart dose than FB (P<.01). The mean heart doses for the P-DIBH plans were < FB for 22 cases, the maximum dose was < FB for 18 cases. Conclusions: A DIBH plan delivered to a FB patient setup with surface imaging will yield dosimetry similar to that of a plan created and delivered FB. A DIBH plan delivered with even a partial BH can give reduced heart dose compared with FB techniques.

How Important Is a Reproducible Breath Hold for Deep Inspiration Breath Hold Breast Radiation Therapy?

Energy Technology Data Exchange (ETDEWEB)

Wiant, David, E-mail: David.wiant@conehealth.com; Wentworth, Stacy; Liu, Han; Sintay, Benjamin

2015-11-15

Purpose: Deep inspiration breath hold (DIBH) for left-sided breast cancer has been shown to reduce heart dose. Surface imaging helps to ensure accurate breast positioning, but it does not guarantee a reproducible breath hold (BH) at DIBH treatments. We examine the effects of variable BH positions for DIBH treatments. Methods and Materials: Twenty-five patients who underwent free breathing (FB) and DIBH scans were reviewed. Four plans were created for each patient: FB, DIBH, FB-DIBH (the DIBH plans were copied to the FB images and recalculated, and image registration was based on breast tissue), and P-DIBH (a partial BH with the heart shifted midway between the FB and DIBH positions). The FB-DIBH plans give a “worst-case” scenario for surface imaging DIBH, where the breast is aligned by surface imaging but the patient is not holding their breath. Kolmogorov-Smirnov tests were used to compare the dose metrics. Results: The DIBH plans gave lower heart dose and comparable breast coverage versus FB in all cases. The FB-DIBH plans showed no significant difference versus FB plans for breast coverage, mean heart dose, or maximum heart dose (P≥.10). The mean heart dose differed between FB-DIBH and FB by <2 Gy for all cases, and the maximum heart dose differed by <2 Gy for 21 cases. The P-DIBH plans showed significantly lower mean heart dose than FB (P<.01). The mean heart doses for the P-DIBH plans were

Compliant walking appears metabolically advantageous at extreme step lengths.

Science.gov (United States)

Kim, Jaehoon; Bertram, John E A

2018-05-19

Humans alter gait in response to unusual gait circumstances to accomplish the task of walking. For instance, subjects spontaneously increase leg compliance at a step length threshold as step length increases. Here we test the hypothesis that this transition occurs based on the level of energy expenditure, where compliant walking becomes less energetically demanding at long step lengths. To map and compare the metabolic cost of normal and compliant walking as step length increases. 10 healthy individuals walked on a treadmill using progressively increasing step lengths (100%, 120%, 140% and 160% of preferred step length), in both normal and compliant leg walking as energy expenditure was recorded via indirect calorimetry. Leg compliance was controlled by lowering the center-of-mass trajectory during stance, forcing the leg to flex and extend as the body moved over the foot contact. For normal step lengths, compliant leg walking was more costly than normal walking gait, but compliant leg walking energetic cost did not increase as rapidly for longer step lengths. This led to an intersection between normal and compliant walking cost curves at 114% relative step length (regression analysis; r 2  = 0.92 for normal walking; r 2  = 0.65 for compliant walking). Compliant leg walking is less energetically demanding at longer step lengths where a spontaneous shift to compliant walking has been observed, suggesting the human motor control system is sensitive to energetic requirements and will employ alternate movement patterns if advantageous strategies are available. The transition could be attributed to the interplay between (i) leg work controlling body travel during single stance and (ii) leg work to control energy loss in the step-to-step transition. Compliant leg walking requires more stance leg work at normal step lengths, but involves less energy loss at the step-to-step transition for very long steps. Copyright © 2018 Elsevier B.V. All rights reserved.

Breath-hold gadolinium-enhanced MRA : clinical application

International Nuclear Information System (INIS)

Kang, Sung Gwon; Kang, Ji Hee; Kim, Won Hong; Lim, Myung Kwan; Cho, Young Kook; Cho, Soon Gu; Suh, Chang Hae

1998-01-01

The purpose of this study is to compare breath-hold gadolinium enhanced MR angiography (MRA) with digital subtraction angiography. Ten patients underwent angiography and breath-hold gadolinium enhanced MRA; the latter performed at 1.5T with 3D FSPGR after a bolus injection of gadopentetate dimeglumine (0.4m mol/kg). Seven of ten pathologic conditions (70%) evaluated by both techniques had a similar appearance. The conditions examined were as follows: the artery feeding renal cell carcinoma(n=2); renal artery stenosis (n=2); pulmonary AVM(n=2); abdominal aortic aneurysm (n=1); atheromatous plaque in the lower abdominal aorta (n=1); an enlarged bronchial artery (n=1); and an aberrant renal artery (n=1). For evaluating an anatomic relationship, a reconstructed 3D image obtained by MRA is more advantageous. Breath hold contrast enhanced MRA is a potentially useful noninvasive screening method for detecting vascular abnormality of the aorta and its branches. (author). 13 refs., 1 tab., 4 figs

Breath-hold gadolinium-enhanced MRA : clinical application

Energy Technology Data Exchange (ETDEWEB)

Kang, Sung Gwon; Kang, Ji Hee; Kim, Won Hong; Lim, Myung Kwan; Cho, Young Kook; Cho, Soon Gu; Suh, Chang Hae [Inha University Hospital, Inchon (Korea, Republic of)

1998-05-01

The purpose of this study is to compare breath-hold gadolinium enhanced MR angiography (MRA) with digital subtraction angiography. Ten patients underwent angiography and breath-hold gadolinium enhanced MRA; the latter performed at 1.5T with 3D FSPGR after a bolus injection of gadopentetate dimeglumine (0.4m mol/kg). Seven of ten pathologic conditions (70%) evaluated by both techniques had a similar appearance. The conditions examined were as follows: the artery feeding renal cell carcinoma(n=2); renal artery stenosis (n=2); pulmonary AVM(n=2); abdominal aortic aneurysm (n=1); atheromatous plaque in the lower abdominal aorta (n=1); an enlarged bronchial artery (n=1); and an aberrant renal artery (n=1). For evaluating an anatomic relationship, a reconstructed 3D image obtained by MRA is more advantageous. Breath hold contrast enhanced MRA is a potentially useful noninvasive screening method for detecting vascular abnormality of the aorta and its branches. (author). 13 refs., 1 tab., 4 figs.

Running for exercise mitigates age-related deterioration of walking economy.

Science.gov (United States)

Ortega, Justus D; Beck, Owen N; Roby, Jaclyn M; Turney, Aria L; Kram, Rodger

2014-01-01

Impaired walking performance is a key predictor of morbidity among older adults. A distinctive characteristic of impaired walking performance among older adults is a greater metabolic cost (worse economy) compared to young adults. However, older adults who consistently run have been shown to retain a similar running economy as young runners. Unfortunately, those running studies did not measure the metabolic cost of walking. Thus, it is unclear if running exercise can prevent the deterioration of walking economy. To determine if and how regular walking vs. running exercise affects the economy of locomotion in older adults. 15 older adults (69 ± 3 years) who walk ≥ 30 min, 3x/week for exercise, "walkers" and 15 older adults (69 ± 5 years) who run ≥ 30 min, 3x/week, "runners" walked on a force-instrumented treadmill at three speeds (0.75, 1.25, and 1.75 m/s). We determined walking economy using expired gas analysis and walking mechanics via ground reaction forces during the last 2 minutes of each 5 minute trial. We compared walking economy between the two groups and to non-aerobically trained young and older adults from a prior study. Older runners had a 7-10% better walking economy than older walkers over the range of speeds tested (p = .016) and had walking economy similar to young sedentary adults over a similar range of speeds (p =  .237). We found no substantial biomechanical differences between older walkers and runners. In contrast to older runners, older walkers had similar walking economy as older sedentary adults (p =  .461) and ∼ 26% worse walking economy than young adults (peconomy whereas walking for exercise appears to have minimal effect on the age-related deterioration in walking economy.

Biomechanical implications of walking with indigenous footwear.

Science.gov (United States)

Willems, Catherine; Stassijns, Gaetane; Cornelis, Wim; D'Août, Kristiaan

2017-04-01

This study investigates biomechanical implications of walking with indigenous "Kolhapuri" footwear compared to barefoot walking among a population of South Indians. Ten healthy adults from South India walked barefoot and indigenously shod at voluntary speed on an artificial substrate. The experiment was repeated outside, on a natural substrate. Data were collected from (1) a heel-mounted 3D-accelerometer recording peak impact at heel contact, (2) an ankle-mounted 3D-goniometer (plantar/dorsiflexion and inversion/eversion), and (3) sEMG electrodes at the m. tibialis anterior and the m. gastrocnemius medialis. Data show that the effect of indigenous footwear on the measured variables, compared to barefoot walking, is relatively small and consistent between substrates (even though subjects walked faster on the natural substrate). Walking barefoot, compared to shod walking yields higher impact accelerations, but the differences are small and only significant for the artificial substrate. The main rotations of the ankle joint are mostly similar between conditions. Only the shod condition shows a faster ankle rotation over the rapid eversion motion on the natural substrate. Maximal dorsiflexion in late stance differs between the footwear conditions on an artificial substrate, with the shod condition involving a less dorsiflexed ankle, and the plantar flexion at toe-off is more extreme when shod. Overall the activity pattern of the external foot muscles is similar. The indigenous footwear studied (Kolhapuri) seems to alter foot biomechanics only in a subtle way. While offering some degree of protection, walking in this type of footwear resembles barefoot gait and this type of indigenous footwear might be considered "minimal". © 2017 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc.

I Walk My Dog Because It Makes Me Happy: A Qualitative Study to Understand Why Dogs Motivate Walking and Improved Health

Science.gov (United States)

Marvin, Garry; Perkins, Elizabeth

2017-01-01

Dog walking is a popular everyday physical activity. Dog owners are generally more active than non-owners, but some rarely walk with their dog. The strength of the dog–owner relationship is known to be correlated with dog walking, and this qualitative study investigates why. Twenty-six interviews were combined with autoethnography of dog walking experiences. Dog walking was constructed as “for the dog”, however, owners represented their dog’s needs in a way which aligned with their own. Central to the construction of need was perceptions of dog personality and behaviour. Owners reported deriving positive outcomes from dog walking, most notably, feelings of “happiness”, but these were “contingent” on the perception that their dogs were enjoying the experience. Owner physical activity and social interaction were secondary bonuses but rarely motivating. Perceptions and beliefs of owners about dog walking were continually negotiated, depending on how the needs of the owner and dog were constructed at that time. Complex social interactions with the “significant other” of a pet can strongly motivate human health behaviour. Potential interventions to promote dog walking need to account for this complexity and the effect of the dog-owner relationship on owner mental wellbeing. PMID:28825614

Generating random walks and polygons with stiffness in confinement

International Nuclear Information System (INIS)

Diao, Y; Ernst, C; Saarinen, S; Ziegler, U

2015-01-01

The purpose of this paper is to explore ways to generate random walks and polygons in confinement with a bias toward stiffness. Here the stiffness refers to the curvature angle between two consecutive edges along the random walk or polygon. The stiffer the walk (polygon), the smaller this angle on average. Thus random walks and polygons with an elevated stiffness have lower than expected curvatures. The authors introduced and studied several generation algorithms with a stiffness parameter s>0 that regulates the expected curvature angle at a given vertex in which the random walks and polygons are generated one edge at a time using conditional probability density functions. Our generating algorithms also allow the generation of unconfined random walks and polygons with any desired mean curvature angle. In the case of random walks and polygons confined in a sphere of fixed radius, we observe that, as expected, stiff random walks or polygons are more likely to be close to the confinement boundary. The methods developed here require that the random walks and random polygons be rooted at the center of the confinement sphere. (paper)

Walking Robots Dynamic Control Systems on an Uneven Terrain

Directory of Open Access Journals (Sweden)

MUNTEANU, M. S.

2010-05-01

Full Text Available The paper presents ZPM dynamic control of walking robots, developing an open architecture real time control multiprocessor system, in view of obtaining new capabilities for walking robots. The complexity of the movement mechanism of a walking robot was taken into account, being a repetitive tilting process with numerous instable movements and which can lead to its turnover on an uneven terrain. The control system architecture for the dynamic robot walking is presented in correlation with the control strategy which contains three main real time control loops: balance robot control using sensorial feedback, walking diagram control with periodic changes depending on the sensorial information during each walk cycle, predictable movement control based on a quick decision from the previous experimental data. The results obtained through simulation and experiments show an increase in mobility, stability in real conditions and obtaining of high performances related to the possibility of moving walking robots on terrains with a configuration as close as possible to real situations, respectively developing new technological capabilities of the walking robot control systems for slope movement and walking by overtaking or going around obstacles.

Development and Evaluation of Algorithms for Breath Alcohol Screening.

Science.gov (United States)

Ljungblad, Jonas; Hök, Bertil; Ekström, Mikael

2016-04-01

Breath alcohol screening is important for traffic safety, access control and other areas of health promotion. A family of sensor devices useful for these purposes is being developed and evaluated. This paper is focusing on algorithms for the determination of breath alcohol concentration in diluted breath samples using carbon dioxide to compensate for the dilution. The examined algorithms make use of signal averaging, weighting and personalization to reduce estimation errors. Evaluation has been performed by using data from a previously conducted human study. It is concluded that these features in combination will significantly reduce the random error compared to the signal averaging algorithm taken alone.

Quantum walk with one variable absorbing boundary

International Nuclear Information System (INIS)

Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

2017-01-01

Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks. - Highlights: • A novel scheme about quantum walk with variable boundary is proposed. • The analytical results of the survival probability from the absorbing boundary. • The behavior of survival probability under different boundary conditions. • The influence of different initial coin states on the survival probability.

Universe out of a breathing bubble

International Nuclear Information System (INIS)

Guendelman, Eduardo I.; Sakai, Nobuyuki

2008-01-01

We consider the model of a false-vacuum bubble with a thin wall where the surface energy density is composed of two different components, 'domain-wall' type and 'dust' type, with opposite signs. We find stably oscillating solutions, which we call 'breathing bubbles'. By decay to a lower mass state, such a breathing bubble could become either (i) a child universe or ii) a bubble that 'eats up' the original universe, depending on the sign of the surface energy of the domain-wall component. We also discuss the effect of the finite-thickness corrections to the thin-wall approximation and possible origins of the energy contents of our model

Two Legged Walking Robot

OpenAIRE

Kraus, V.

2015-01-01

The aim of this work is to construct a two-legged wirelessly controlled walking robot. This paper describes the construction of the robot, its control electronics, and the solution of the wireless control. The article also includes a description of the application to control the robot. The control electronics of the walking robot are built using the development kit Arduino Mega, which is enhanced with WiFi module allowing the wireless control, a set of ultrasonic sensors for detecting obstacl...

Health, social and economical consequences of sleep-disordered breathing

DEFF Research Database (Denmark)

Jennum, Poul; Kjellberg, Jakob

2011-01-01

The objective direct and indirect costs of sleep-disordered breathing (snoring, sleep apnoea (SA) and obesity hypoventilation syndrome (OHS)) and the treatment are incompletely described.......The objective direct and indirect costs of sleep-disordered breathing (snoring, sleep apnoea (SA) and obesity hypoventilation syndrome (OHS)) and the treatment are incompletely described....

Association between breastfeeding and breathing pattern in children: a sectional study

Directory of Open Access Journals (Sweden)

Teresinha S.P. Lopes

2014-07-01

Full Text Available OBJECTIVE: to determine the prevalence of mouth breathing and to associate the history of breastfeeding with breathing patterns in children. METHODS: this was an observational study with 252 children of both genders, aged 30 to 48 months, who participated in a dental care program for mothers and newborns. As an instrument of data collection, a semi-structured questionnaire was administered to the children's mothers assessing the form and duration of breastfeeding and the oral habits of non-nutritive sucking. To determine the breathing patterns that the children had developed, medical history and clinical examination were used. Statistical analysis was conducted to examine the effects of exposure on the primary outcome (mouth breathing, and the prevalence ratio was calculated with a 95% confidence interval. RESULTS: of the total sample, 43.1% of the children were mouth breathers, 48.4% had been breastfed exclusively until six months of age or more, and 27.4% had non-nutritive sucking habits. Statistically significant associations were found for bottle-feeding (p < 0.001 and oral habits of non-nutritive sucking (p = 0.009, with an increased likelihood of children exhibiting a predominantly oral breathing pattern. A statistically significant association was also observed between a longer duration of exclusive breastfeeding and a nasal breathing pattern presented by children. CONCLUSION: an increased duration of exclusive breastfeeding lowers the chances of children exhibiting a predominantly oral breathing pattern.

Efficient quantum circuit implementation of quantum walks

International Nuclear Information System (INIS)

Douglas, B. L.; Wang, J. B.

2009-01-01

Quantum walks, being the quantum analog of classical random walks, are expected to provide a fruitful source of quantum algorithms. A few such algorithms have already been developed, including the 'glued trees' algorithm, which provides an exponential speedup over classical methods, relative to a particular quantum oracle. Here, we discuss the possibility of a quantum walk algorithm yielding such an exponential speedup over possible classical algorithms, without the use of an oracle. We provide examples of some highly symmetric graphs on which efficient quantum circuits implementing quantum walks can be constructed and discuss potential applications to quantum search for marked vertices along these graphs.

On the physical realizability of quantum stochastic walks

Science.gov (United States)

Taketani, Bruno; Govia, Luke; Schuhmacher, Peter; Wilhelm, Frank

Quantum walks are a promising framework that can be used to both understand and implement quantum information processing tasks. The recently developed quantum stochastic walk combines the concepts of a quantum walk and a classical random walk through open system evolution of a quantum system, and have been shown to have applications in as far reaching fields as artificial intelligence. However, nature puts significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution, and the physical assumptions underpinning them. We then introduce a way to circumvent some of these restrictions, and simulate a more general quantum stochastic walk on a quantum computer, using a technique we call quantum trajectories on a quantum computer. We finally describe a circuit QED approach to implement discrete time quantum stochastic walks.

Cardiorespiratory and autonomic interactions during snoring related resistive breathing.

Science.gov (United States)

Mateika, J H; Mitru, G

2001-03-15

We hypothesized that blood pressure (BP) is less during snoring as compared to periods of non-snoring in non-apneic individuals. Furthermore, we hypothesized that this reduction may be accompanied by a simultaneous decrease in sympathetic (SNSA) and parasympathetic (PNSA) nervous system activity and an increase in heart rate (HR). N/A. N/A. N/A. The variables mentioned above in addition to breathing frequency were measured in 9 subjects during NREM sleep. In addition, the lowest systolic (SBP) and diastolic blood pressure (DBP) during inspiration and the highest SBP and DBP during expiration was determined breath-by-breath from segments selected from each NREM cycle. Heart rate variability was used as a marker of autonomic nervous system activity. Our results showed that BP during snoring decreased compared to non-snoring and the breath-by-breath BP analysis suggested that this difference may have been mediated by changes in intrathoracic pressure. In conjunction with the decrease in BP, SNSA decreased and HR increased however PNSA remained constant. Thus, a decrease in PNSA was likely not the primary mechanism responsible for the HR response. We conclude that BP responses and SNSA during snoring are similar to that reported previously in non-snoring individuals. However, the causal mechanisms maybe different and manifested in other measures such as HR. Thus, nocturnal cardiovascular and autonomic function maybe uniquely different in non-apneic snoring individuals.

Acoustic rhinometry in mouth breathing patients: a systematic review.

Science.gov (United States)

Melo, Ana Carolina Cardoso de; Gomes, Adriana de Oliveira de Camargo; Cavalcanti, Arlene Santos; Silva, Hilton Justino da

2015-01-01

When there is a change in the physiological pattern of nasal breathing, mouth breathing may already be present. The diagnosis of mouth breathing is related to nasal patency. One way to access nasal patency is by acoustic rhinometry. To systematically review the effectiveness of acoustic rhinometry for the diagnosis of patients with mouth breathing. Electronic databases LILACS, MEDLINE via PubMed and Bireme, SciELO, Web of Science, Scopus, PsycInfo, CINAHL, and Science Direct, from August to December 2013, were consulted. 11,439 articles were found: 30 from LILACS, 54 from MEDLINE via Bireme, 5558 from MEDLINE via PubMed, 11 from SciELO, 2056 from Web of Science, 1734 from Scopus, 13 from PsycInfo, 1108 from CINAHL, and 875 from Science Direct. Of these, two articles were selected. The heterogeneity in the use of equipment and materials for the assessment of respiratory mode in these studies reveals that there is not yet consensus in the assessment and diagnosis of patients with mouth breathing. According to the articles, acoustic rhinometry has been used for almost twenty years, but controlled studies attesting to the efficacy of measuring the geometry of nasal cavities for complementary diagnosis of respiratory mode are warranted. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Does walking strategy in older people change as a function of walking distance?

Science.gov (United States)

Najafi, Bijan; Helbostad, Jorunn L; Moe-Nilssen, Rolf; Zijlstra, Wiebren; Aminian, Kamiar

2009-02-01

This study investigates whether the spatio-temporal parameters of gait in the elderly vary as a function of walking distance. The gait pattern of older subjects (n=27) over both short (SWDLWD>20 m) walking was evaluated using an ambulatory device consisting of body-worn sensors (Physilog). The stride velocity (SV), gait cycle time (GCT), and inter-cycle variability of each parameter (CV) were evaluated for each subject. Analysis was undertaken after evaluating the errors and the test-retest reliability of the Physilog device compared with an electronic walkway system (GaitRite) over the SWD with different walking speeds. While both systems were highly reliable with respect to the SV and GCT parameters (ICC>0.82), agreement for the gait variability was poor. Interestingly, our data revealed that the measured gait parameters over SWD and LWD were significantly different. LWD trials had a mean increase of 5.2% (pLWD trials decreased by an average of 1% relative to the SWD case, the drop was not significant. Moreover, reliability for gait variability measures was poor, irrespective of the instrument and despite a moderate improvement for LWD trials. Taken together, our findings indicate that for valid and reliable comparisons, test and retest should be performed under identical distance conditions. Furthermore, our findings suggest that the older subjects may choose different walking strategies for SWD and LWD conditions.

More Adults Are Walking PSA (:60)

Centers for Disease Control (CDC) Podcasts

This 60 second PSA is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.

Rhythmic walking interaction with auditory feedback

DEFF Research Database (Denmark)

Maculewicz, Justyna; Jylhä, Antti; Serafin, Stefania

2015-01-01

We present an interactive auditory display for walking with sinusoidal tones or ecological, physically-based synthetic walking sounds. The feedback is either step-based or rhythmic, with constant or adaptive tempo. In a tempo-following experiment, we investigate different interaction modes...