scholarly journals Association between Oxygen Consumption and Surface Electromyographic Amplitude and Its Variation within Individual Calf Muscles during Walking at Various Speeds

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1748
Author(s):  
Kohei Watanabe ◽  
Shideh Narouei
Keyword(s):  
Oxygen Consumption ◽  
Spatial Variation ◽  
Metabolic Response ◽  
Correlation Coefficients ◽  
Surface Emg ◽  
Medial Gastrocnemius ◽  
Whole Body ◽  
Young Males ◽  
Emg Amplitude ◽  
Calf Muscles

Surface electromyography (EMG) has been used to estimate muscle work and physiological burden of the whole body during human movements. However, there are spatial variations in surface EMG responses within individual muscles. The aim of this study was to investigate the relation between oxygen consumption and surface EMG responses of lower leg muscles during walking at various speeds and to quantify its spatial variation within an individual muscle. Nine young males walked on a treadmill at four speeds: preferred minus 1 km/h, preferred, preferred plus 1 km/h, and preferred plus 2 km/h, and the metabolic response was measured based on the expired gas. High-density surface EMG of the tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius, and soleus muscles was performed using 64 two-dimensional electrode grids. Correlation coefficients between oxygen consumption and the surface EMG amplitude were calculated across the gait speeds for each channel in the electrode grid and for individual muscles. Mean correlation coefficients across electrodes were 0.69–0.87 for the four individual muscles, and the spatial variation of correlation between the surface EMG amplitude and oxygen consumption within an electrode grid was significantly greater in MG muscle than in TA muscle (Quartile deviations: 0.24 for MG and 0.02 for TA, p < 0.05). These results suggest that the physiological burden of the whole body during gait at various speeds can be estimated from the surface EMG amplitude of calf muscles, but we need to note its spatial distribution within the MG muscle.

scholarly journals IAP-AACM v1.0： Global to regional evaluation of the atmospheric chemistry model in CAS-ESM

2018 ◽  
Author(s):  
Ying Wei ◽  
Xueshun Chen ◽  
Huansheng Chen ◽  
Jie Li ◽  
Zifa Wang ◽  
...  
Keyword(s):  
East Asia ◽  
Spatial Variation ◽  
Atmospheric Chemistry ◽  
Comprehensive Evaluation ◽  
Correlation Coefficients ◽  
Full Description ◽  
Atmospheric Physics ◽  
Temporal And Spatial Variability ◽  
Fine Mode ◽  
Aerosol Effects

Abstract. In this study, a full description and comprehensive evaluation of a global-regional nested model, the Aerosol and Atmospheric Chemistry Model of the Institute of Atmospheric Physics (IAP-AACM), is presented for the first time. Not only the global budgets and distribution, but also a comparison of nested simulation over China against multi-datasets are investigated, benefiting from the access of air quality monitoring data in China since 2013 and the Model Inter-Comparison Study for Asia project. The model results and analysis can greatly help reduce uncertainties and understand model diversity in assessing global and regional aerosol effects, especially over East Asia and areas affected by East Asia. The 1-year simulation for 2014 shows that the IAP-AACM is within the range of other models, and well reproduces both spatial distribution and seasonal variation of trace gases and aerosols over major continents and oceans (mostly within the factor of two). The model nicely captures spatial variation for carbon monoxide except an underestimation over the ocean that also shown in other models, which suggests the need for more accurate emission rate of ocean source. For aerosols, the simulation of fine-mode particulate matter (PM2.5) matches observation well and it has a better simulating ability on primary aerosols than secondary aerosols. This calls for more investigation on aerosol chemistry. Furthermore, IAP-AACM shows the superiority of global model, compared with regional model, on performing regional transportation for the nested simulation over East Asia. For the city evaluation over China, the model reproduces variation of sulfur dioxide (SO2), nitrogen dioxide (NO2) and PM2.5 accurately in most cities, with correlation coefficients above 0.5. Compared to the global simulation, the nested simulation exhibits an improved ability to capture the high temporal and spatial variability over China. In particular, the correlation coefficients for PM2.5, SO2 and NO2 are raised by ~ 0.25, ~ 0.15 and ~ 0.2 respectively in the nested grid. The summary provides constructive information for the application of chemical transport models. In future, we recommend the model's ability to capture high spatial variation of PM2.5 is yet to be improved.

Rectification is required to extract oscillatory envelope modulation from surface electromyographic signals

2014 ◽  
Vol 112 (7) ◽  
pp. 1685-1691 ◽  
Author(s):  
Christopher J. Dakin ◽  
Brian H. Dalton ◽  
Billy L. Luu ◽  
Jean-Sébastien Blouin
Keyword(s):  
Motor Unit ◽  
Stimulus Frequency ◽  
Motor Units ◽  
Surface Emg ◽  
Medial Gastrocnemius ◽  
Single Motor Unit ◽  
Single Motor ◽  
Single Motor Units ◽  
Emg Signal ◽  
Envelope Modulation

Rectification of surface electromyographic (EMG) recordings prior to their correlation with other signals is a widely used form of preprocessing. Recently this practice has come into question, elevating the subject of EMG rectification to a topic of much debate. Proponents for rectifying suggest it accentuates the EMG spike timing information, whereas opponents indicate it is unnecessary and its nonlinear distortion of data is potentially destructive. Here we examine the necessity of rectification on the extraction of muscle responses, but for the first time using a known oscillatory input to the muscle in the form of electrical vestibular stimulation. Participants were exposed to sinusoidal vestibular stimuli while surface and intramuscular EMG were recorded from the left medial gastrocnemius. We compared the unrectified and rectified surface EMG to single motor units to determine which method best identified stimulus-EMG coherence and phase at the single-motor unit level. Surface EMG modulation at the stimulus frequency was obvious in the unrectified surface EMG. However, this modulation was not identified by the fast Fourier transform, and therefore stimulus coherence with the unrectified EMG signal failed to capture this covariance. Both the rectified surface EMG and single motor units displayed significant coherence over the entire stimulus bandwidth (1–20 Hz). Furthermore, the stimulus-phase relationship for the rectified EMG and motor units shared a moderate correlation ( r = 0.56). These data indicate that rectification of surface EMG is a necessary step to extract EMG envelope modulation due to motor unit entrainment to a known stimulus.

Metabolic responses of the whole body, portal-drained viscera and hindquarter to adrenaline infusion: Effects of nonselective and selective β-adrenoceptor blockade

1997 ◽  
Vol 77 (2) ◽  
pp. 307-316 ◽  
Author(s):  
J. O. O. Miaron ◽  
R. J. Christopherson
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Portal Vein ◽  
Influencing Factor ◽  
External Iliac Artery ◽  
Open Circuit ◽  
Whole Body ◽  
Organ Blood Flow ◽  
Β Blocker ◽  
Β Blockers

Propranolol, a nonselective β-blocker and selective β-blockers (metoprolol a β1-blocker and ICI 118551 a β2-blocker) were used to investigate the β-adrenoceptor-mediated adrenaline-induced increase in whole-body and organ VO2 in five whether sheep. Transit time blood flow probes were chronically implanted on the portal vein and the external iliac artery and sampling catheters were placed in the mesenteric artery, iliac vein and portal vein. Oxygen consumption by the whole body was measured by open circuit calorimetry, and oxygen consumption by the portal-drained viscera and the hindquarter was determined from A-VO2 differences and organ blood flow. Absolute pre-infusion VO2 values for the whole body, portal-drained viscera and hindquarters were 236 ± 7.4, 61 ± 6.0 and 13 ± 3.1 mL min−1 respectively. The mean changes in VO2 in response to infusion were 74 vs. 11, 26, 10 and 12 mL min−1 (SE = 9.1) for whole body; 31 vs. −2, −15, 13 and −4 mL min−1 (SE = 7.3) for portal-drained viscera and 8 vs. −0.4, 2.1, 1.0 and −2.7 mL min−1; SE = 4.3) for hindquarters during adrenaline, control, propranolol, metoprolol and ICI 118551 treatments, respectively. Adrenaline increased VO2 (P < 0.05) in the whole body and portal-drained viscera, but not hindquarters relative to controls. All β-blockers suppressed (P < 0.05) the adrenaline-induced increase in VO2 except for the portal-drained viscera where metoprolol was less effective and the hindquarters where β-blockers had no effect. The blood flow pattern was similar to VO2 responses for the portal-drained viscera. The nonselective β1 and β2 blockers were effective in reducing the adrenaline-induced increases in blood flow from the portal-drained viscera and to the hindquarters, with more pronounced β-adrenoceptor-mediated haemodynamic effects. The results indicate that the β-adrenoceptor system modulates whole body VO2, clearly establishes that adrenaline induces an increased VO2 in portal-drained viscera which can be reversed by a β2 or nonselective β blocker and implicates β adrenoceptors as an influencing factor in the maintenance energy requirements of ruminants. Key words: Calorimetry, adrenaline, β blockers, blood flow, sheep

Whole body oxygen consumption and critical oxygen delivery in response to prolonged and severe carbon monoxide poisoning

Resuscitation ◽  
2003 ◽  
Vol 56 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Howard A Smithline ◽  
Kevin R Ward ◽  
Donald A Chiulli ◽  
Heidi C Blake ◽  
Emanuel P Rivers
Keyword(s):  
Carbon Monoxide ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Carbon Monoxide Poisoning ◽  
Whole Body ◽  
Critical Oxygen

scholarly journals The metabolic response of the Bradypus sloth to temperature

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
High Power ◽  
Metabolic Response ◽  
Metabolic Responses ◽  
Metabolic Depression ◽  
Wide Range ◽  
Energetic Constraints ◽  
Power Costs

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

scholarly journals Assessment of whole-body vibration exposure of mining truck drivers

2020 ◽  
Vol 120 (9) ◽  
Author(s):  
B. Erdem ◽  
T. Dogan ◽  
Z. Duran
Keyword(s):  
Health Effect ◽  
Whole Body Vibration ◽  
Correlation Coefficients ◽  
Dominant Frequency ◽  
Truck Drivers ◽  
Whole Body ◽  
Vibration Acceleration ◽  
Body Vibration ◽  
Dump Trucks ◽  
Iso 2631

SYNOPSIS Whole-body vibration (WBV) exposure measurements taken from 105 truck drivers employed in 19 mines and other workplaces were evaluated with the criteria prescribed in EU 2002/44/EC directive, BS 6841 (1987), ISO 2631-1 (1997). and ISO 2631-5 (2004) standards. The highest vibration acceleration was measured on the vertical Z-axis. The highest WBV exposure occurred in the RETURN, HAUL, and SPOT phases while the lowest exposure took place in the LOAD and WAIT phases. Crest factors on all axes were generally greater than nine, yet strong correlation coefficients were achieved in VDV-eVDV analyses. Driver seats generally dampened the vibration along the Z-axis but exacerbated it along X and Y axes. The dominant frequency for the X and Y-axes rose up to 40 Hz while it ranged between 1 Hz and 2.5 Hz along the Z-axis. While the probability of an adverse health effect was higher with BS 6841 (1987) and ISO 2631-1 (1997) standards, it was low according to EU 2002/44/EC and ISO 2631-5 (2004). The 91 t, 100 t, and 170 t capacity trucks produced lower vibration magnitudes. Drivers were exposed to approximately equivalent levels of WBV acceleration and dose in contractor-type trucks and mining trucks. Rear-dump trucks exposed their drivers to a slightly higher level of vibration than bottom-dump trucks. Underground trucks exposed their drivers to a significantly higher level of vibration than mining trucks. Both driver age and driver experience were inversely proportional to vibration acceleration and dose. Conversely, there was a positive relationship between the truck service years and the WBV acceleration and dose to which drivers were exposed to. Loads of blocky material exposed drivers to higher vibration acceleration and dose levels than non-blocky material. Keywords: whole-body vibration, mining truck, A(8), BS 6841, EU 2002/EC/44, ISO 2631-1, ISO 2631-5, VDV(8).

scholarly journals Satisfied quantitative value can be acquired by short-time bone SPECT/CT using a whole-body cadmium–zinc–telluride gamma camera

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiko Yamane ◽  
Masafumi Takahashi ◽  
Yohji Matsusaka ◽  
Kenji Fukushima ◽  
Akira Seto ◽  
...  
Keyword(s):  
Cadmium Zinc Telluride ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Zinc Telluride ◽  
Whole Body ◽  
Metastatic Lesions ◽  
Standardized Uptake Values ◽  
Bone Spect ◽  
Short Time ◽  
Cadmium Zinc

AbstractThe aim of this study was to evaluate the quantitative values of short-time scan (STS) of metastatic lesions compared with a standard scan (SS) when acquired by whole-body bone SPECT/CT with cadmium–zinc–telluride (CZT) detectors. We retrospectively reviewed 13 patients with bone metastases from prostate cancer, who underwent SPECT/CT performed on whole-body CZT gamma cameras. STSs were obtained using 75, 50, 25, 10, and 5% of the list-mode data for SS, respectively. Regions of interest (ROIs) were set on the increased uptake areas diagnosed as metastases. Intraclass correlation coefficients (ICCs) of standardized uptake values (SUVs) for the ROIs were calculated between the SS and each STS, and ICC ≥ 0.8 was set as a perfect correlation. Moreover, the repeatability coefficient (RC) was calculated, and RC ≤ 20% was defined as acceptable. A total of 152 metastatic lesions were included in the analysis. The ICCs between the SS vs. 75%-STS, 50%-STS, 25%-STS, 10%-STS, and 5%-STS were 0.999, 0.997, 0.994, 0.983, and 0.955, respectively. The RCs of the SS vs. 75%-STS, 50%-STS, 25%-STS, 10%-STS, and 5%-STS were 7.9, 12.4, 19.8, 30.8, and 41.3%, respectively. When evaluating the quality of CZT bone SPECT/CT acquired by a standard protocol, 25%-STS may provide adequate quantitative values.

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