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Miller JD, Fry AC, Ciccone AB, Poggio J. Analysis of Rate of Force Development as a Vertical Jump Height Predictor. Res Q Exerc Sport 2023; 94:638-645. [PMID: 35442167 DOI: 10.1080/02701367.2022.2036315] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Purpose: Many researchers and coaches hold that the ability to generate force rapidly is an important factor in athletic performance. This concept is often studied by analyzing the rate of ground reaction force development (RFD) during vertical jumps; however, many such studies disagree on whether estimates of RFD are true predictors of vertical jump height, have limited sample sizes, and have not employed multiple regression analysis. Therefore, the purpose of the study was to assess the utility of RFD as a predictor of vertical jump height. Methods: Forward sequential multiple regression models were performed using kinematic, kinetic, and demographic variables from a database of maximal countermovement vertical jumps collected via motion capture system from 2,258 NCAA Division I athletes. Results: Peak RFD was a significant bivariate predictor of vertical jump height (r = 0.408, p < .001). However, when other variables were included in the prediction model the partial variance in vertical jump height accounted for by peak RFD was nearly eliminated (r = -0.051, β = -0.051), but sex (r = 0.246, β = 0.94) and peak ground reaction force (r = 0.503, β = 1.109) emerged as predictors of partial variance in jump height. Furthermore, mediation analysis revealed the direct effect of peak RFD on vertical jump height was only 0.004. Conclusions: Multiple regression analysis enabled by a large sample size suggests Peak RFD may not be uniquely useful as a predictor of vertical jump height during maximal countermovement jumps.
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Olmos AA, Sterczala AJ, Parra ME, Dimmick HL, Miller JD, Deckert JA, Sontag SA, Gallagher PM, Fry AC, Herda TJ, Trevino MA. Sex-related differences in motor unit behavior are influenced by myosin heavy chain during high- but not moderate-intensity contractions. Acta Physiol (Oxf) 2023; 239:e14024. [PMID: 37551144 DOI: 10.1111/apha.14024] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/09/2023]
Abstract
AIMS Motor unit recruitment and firing rate patterns of the vastus lateralis (VL) have not been compared between sexes during moderate- and high-intensity contraction intensities. Additionally, the influence of fiber composition on potential sex-related differences remains unquantified. METHODS Eleven males and 11 females performed 40% and 70% maximal voluntary contractions (MVCs). Surface electromyographic (EMG) signals recorded from the VL were decomposed. Recruitment thresholds (RTs), MU action potential amplitudes (MUAPAMP ), initial firing rates (IFRs), mean firing rates (MFRs), and normalized EMG amplitude (N-EMGRMS ) at steady torque were analyzed. Y-intercepts and slopes were calculated for MUAPAMP , IFR, and MFR versus RT relationships. Type I myosin heavy chain isoform (MHC) was determined with muscle biopsies. RESULTS There were no sex-related differences in MU characteristics at 40% MVC. At 70% MVC, males exhibited greater slopes (p = 0.002) for the MUAPAMP , whereas females displayed greater slopes (p = 0.001-0.007) for the IFR and MFR versus RT relationships. N-EMGRMS at 70% MVC was greater for females (p < 0.001). Type I %MHC was greater for females (p = 0.006), and was correlated (p = 0.018-0.031) with the slopes for the MUAPAMP , IFR, and MFR versus RT relationships at 70% MVC (r = -0.599-0.585). CONCLUSION Both sexes exhibited an inverse relationship between MU firing rates and recruitment thresholds. However, the sex-related differences in MU recruitment and firing rate patterns and N-EMGRMS at 70% MVC were likely due to greater type I% MHC and smaller twitch forces of the higher threshold MUs for the females. Evidence is provided that muscle fiber composition may explain divergent MU behavior between sexes.
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Affiliation(s)
- Alex A Olmos
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mandy E Parra
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, Texas, USA
| | - Hannah L Dimmick
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan D Miller
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas, USA
| | - Jake A Deckert
- Department of Human Physiology, Gonzaga University, Spokane, Washington, USA
| | - Stephanie A Sontag
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Philip M Gallagher
- Applied Physiology Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Andrew C Fry
- Jayhawk Athletic Performance Laboratory - Wu Tsai Human Performance Alliance, University of Kansas, Lawrence, Kansas, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Michael A Trevino
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
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Cabarkapa D, Cabarkapa DV, Miller JD, Templin TT, Frazer LL, Nicolella DP, Fry AC. Biomechanical characteristics of proficient free-throw shooters-markerless motion capture analysis. Front Sports Act Living 2023; 5:1208915. [PMID: 37601167 PMCID: PMC10436204 DOI: 10.3389/fspor.2023.1208915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/07/2023] [Indexed: 08/22/2023] Open
Abstract
The winning game outcome in basketball is partially contingent on the team's ability to secure and make more free-throw shooting attempts, especially close to the end of the game. Thus, the purpose of the present study was to perform a comprehensive biomechanical analysis of the free-throw shooting motion to examine differences between (a) proficient (≥70%) and non-proficient shooters (<70%) and (b) made and missed free-throw shoots within the proficient group of shooters. Thirty-four recreationally active males with previous basketball playing experience attempted ten consecutive free-throw shots (4.57 m), with a 10-15 s rest interval between each shot. An innovative three-dimensional markerless motion capture system (SwRI Enable, San Antonio, TX, USA) composed of nine high-definition cameras recording at 120 Hz was used to capture and analyze the biomechanical parameters of interest. Independent t-tests and Mann-Whitney U tests were used to examine a presence of statistically significant differences. The findings of the present study reveal that proficient free-throw shooters performed the shooting motion in a more controlled manner by having significantly lower knee and center of mass peak and mean angular velocities. Also, proficient shooters attained a significantly greater release height and had less forward trunk lean when compared to non-proficient shooters at the time point of the ball release. Moreover, despite being beneficial for improvements in shooting accuracy, our findings suggest that overemphasizing the release height may be in certain instances counterproductive, as it may lead to more missed than made free-throw shots within the proficient group of shooters.
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Affiliation(s)
- Dimitrije Cabarkapa
- Jayhawk Athletic Performance Laboratory—Wu Tsai Human Performance Alliance, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, United States
| | - Damjana V. Cabarkapa
- Jayhawk Athletic Performance Laboratory—Wu Tsai Human Performance Alliance, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, United States
| | - Jonathan D. Miller
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, United States
| | | | - Lance L. Frazer
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, United States
| | | | - Andrew C. Fry
- Jayhawk Athletic Performance Laboratory—Wu Tsai Human Performance Alliance, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, United States
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Olmos AA, Sontag SA, Sterczala AJ, Parra ME, Dimmick HL, Miller JD, Deckert JA, Herda TJ, Trevino MA. High-Intensity Cycling Training Necessitates Increased Neuromuscular Demand of the Vastus Lateralis During a Fatiguing Contraction. Res Q Exerc Sport 2023:1-12. [PMID: 37369135 DOI: 10.1080/02701367.2023.2201311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 04/05/2023] [Indexed: 06/29/2023]
Abstract
Purpose: To examine the effects of a 5-week continuous cycling training intervention on electromyographic amplitude (EMGRMS)- and mechanomyographic amplitude (MMGRMS)-torque relationships of the vastus lateralis (VL) during a prolonged contraction. Methods: Twenty-four sedentary, young adults performed maximal voluntary contractions (MVCs) and a prolonged isometric trapezoidal contraction at the same absolute 40% MVC for the knee extensors before (PRE) and after training (POSTABS). Individual b- (slopes) and a-terms (y-intercepts) were calculated from the log-transformed electromyographic amplitude (EMGRMS)- and mechanomyographic amplitude (MMGRMS)-torque relationships during the increasing and decreasing segments of the trapezoid. EMGRMS and MMGRMS was normalized for the 45-s steady torque segment. Results: At PRE, b-terms for the EMGRMS-torque relationships during the linearly decreasing segment were greater than the increasing segment (p < .001), and decreased from PRE to POSTABS (p = .027). a-terms were greater during the linearly increasing than decreasing segment at PRE, while the a-terms for the linearly decreasing segment increased from PRE to POSTABS (p = .027). For the MMGRMS-torque relationships, b-terms during the linearly decreasing segment decreased from PRE to POSTABS (p = .013), while a-terms increased from PRE to POSTABS when collapsed across segments (p = .022). Steady torque EMGRMS increased for POSTABS (p < .001). Conclusion: Although cycling training increased aerobic endurance, incorporating resistance training may benefit athletes/individuals as the alterations in neuromuscular parameters post-training suggest a greater neural cost (EMGRMS) and mechanical output (MMGRMS) to complete the same pre-training fatiguing contraction.
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Miller JD, Cabarkapa D, Miller AJ, Frazer LL, Templin TN, Eliason TD, Garretson SK, Fry AC, Berkland CJ. Novel 3D Force Sensors for a Cost-Effective 3D Force Plate for Biomechanical Analysis. Sensors (Basel) 2023; 23:s23094437. [PMID: 37177650 PMCID: PMC10181757 DOI: 10.3390/s23094437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023]
Abstract
Three-dimensional force plates are important tools for biomechanics discovery and sports performance practice. However, currently, available 3D force plates lack portability and are often cost-prohibitive. To address this, a recently discovered 3D force sensor technology was used in the fabrication of a prototype force plate. Thirteen participants performed bodyweight and weighted lunges and squats on the prototype force plate and a standard 3D force plate positioned in series to compare forces measured by both force plates and validate the technology. For the lunges, there was excellent agreement between the experimental force plate and the standard force plate in the X-, Y-, and Z-axes (r = 0.950-0.999, p < 0.001). For the squats, there was excellent agreement between the force plates in the Z-axis (r = 0.996, p < 0.001). Across axes and movements, root mean square error (RMSE) ranged from 1.17% to 5.36% between force plates. Although the current prototype force plate is limited in sampling rate, the low RMSEs and extremely high agreement in peak forces provide confidence the novel force sensors have utility in constructing cost-effective and versatile use-case 3D force plates.
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Affiliation(s)
- Jonathan D Miller
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS 66045, USA
- Axioforce LLC, St. Louis, MO 63141, USA
| | - Dimitrije Cabarkapa
- Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | | | - Lance L Frazer
- Southwest Research Institute, San Antonio, TX 78238, USA
| | | | | | - Samuel K Garretson
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
| | - Andrew C Fry
- Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | - Cory J Berkland
- Axioforce LLC, St. Louis, MO 63141, USA
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66045, USA
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Maneja RH, Miller JD, Flint JB, Alcaria JFA, Basali AU, Flandez AVB, Gopalan J, Duraisamy T, Abrogueña JBR, Bawazier AA, Das PB, Manokaran S, Asiri YY, Qasem A, Asfahani K, Qurban MAB. Extreme conditions reduce hatching success of green turtles (Chelonia mydas L.) at Karan Island, the major nesting site in the Arabian Gulf. Mar Pollut Bull 2023; 190:114801. [PMID: 36965265 DOI: 10.1016/j.marpolbul.2023.114801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Survival in the early life stages is a major factor determining the growth and stability of wildlife populations. For sea turtles, nest location must provide favorable conditions to support embryonic development. Hatching success and incubation environment of green turtle eggs were examined in July 2019 at Karan Island, a major nesting site for the species in the Arabian Gulf. Mean hatching success averaged at 38.8 % (range = 2.5-75.0 %, n = 14). Eggs that suffered early embryonic death (EED) and late embryonic death (LED) represented 19.8 % (range: 3.3-64.2 %) and 41.4 % (range: 4.8-92.6 %) of the clutch on average, respectively. Nest sand was either coarse (0.5-1 mm: mean 44.8 %, range = 30.4-56.9 % by dry weight, n = 14) or medium (0.25-0.5 mm: mean 33.6 %, range = 12.0-45.5 % by dry weight, n = 14). Mean sand moisture (4.0 %, range = 3.2-4.9 %, n = 14) was at the lower margin for successful development. Hatching success was significantly higher in clutches with sand salinity <1500 EC.uS/cm (n = 5) than those above 2500 EC.uS/cm (n = 5). Mean clutch temperatures at 1200 h increased by an average of 5.4 °C during the 50-d post-oviposition from 31.2 °C to 36.6 °C. Embryos experienced lethally high temperatures in addition to impacts of other environmental factors (salinity, moisture, sand grain size), which was related to reduced hatching success. Conservation initiatives must consider the synergistic influence of the above parameters in formulating strategies to improve the overall resilience of the green turtle population in the Arabian Gulf to anthropogenic and climate change-related stressors.
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Affiliation(s)
- R H Maneja
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - J D Miller
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - J B Flint
- One Welfare and Sustainability Center, Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus 43210, OH, USA
| | - J F A Alcaria
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - A U Basali
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - A V B Flandez
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - J Gopalan
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - T Duraisamy
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - J B R Abrogueña
- Environmental Protection and Control Department, Royal Commission for Jubail and Yanbu, Jazan City for Primary and Downstream Industries, Saudi Arabia
| | - A A Bawazier
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - P B Das
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - S Manokaran
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Y Y Asiri
- Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - A Qasem
- Environmental Protection Department, Saudi Aramco, Dhahran, Saudi Arabia
| | - K Asfahani
- Environmental Protection Department, Saudi Aramco, Dhahran, Saudi Arabia
| | - M A B Qurban
- National Center for Wildlife, Riyadh, Saudi Arabia
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Sontag SA, Parra ME, Dimmick HL, Sterczala AJ, Miller JD, Deckert JA, Gallagher PM, Fry AC, Herda TJ, Trevino MA. A Noninvasive Test For Estimating Type I Myosin Heavy Chain Expression In Women Using Mechanomyography. Med Sci Sports Exerc 2022. [DOI: 10.1249/01.mss.0000880608.96139.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Al Ameri HM, Al Harthi S, Al Kiyumi A, Al Sariri TS, Al-Zaidan ASY, Antonopoulou M, Broderick AC, Chatting M, Das HS, Hesni MA, Mancini A, Miller JD, Mobaraki A, Rezaie-Atagholipour M, Pilcher NJ, Rees AF, Rodríguez-Zárate CJ, Smyth DM, Tanabe LK, Yaghmour F, Yusuf AA, Godley BJ. CORRIGENDUM: Biology and conservation of marine turtles in the northwestern Indian Ocean: a review. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01183_c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- HM Al Ameri
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, Penryn Campus, University of Exeter, Cornwall TR10 9FE, UK
- Marine Assessment and Conservation Section, Terrestrial and Marine Biodiversity Sector, Environment Agency-Abu Dhabi, PO Box 45553, Abu Dhabi, United Arab Emirates
| | - S Al Harthi
- Environment Society of Oman, PO Box 3955, Ruwi PC112, Muscat, Sultanate of Oman
| | - A Al Kiyumi
- PO Box 106 PC134, Jawharat Al Shatie, Muscat, Sultanate of Oman
| | - TS Al Sariri
- Environment Authority, PO Box 323, Muscat, Sultanate of Oman
| | - ASY Al-Zaidan
- Department of Biological Sciences, Faculty of Science, Kuwait University, Safat 13060, Kuwait
| | - M Antonopoulou
- Emirates Nature-WWF, PO Box 73323, Abu Dhabi, United Arab Emirates
| | - AC Broderick
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, Penryn Campus, University of Exeter, Cornwall TR10 9FE, UK
| | - M Chatting
- Environmental Science Centre, Qatar University, PO Box 2713, Doha, Qatar
| | - HS Das
- Marine Assessment and Conservation Section, Terrestrial and Marine Biodiversity Sector, Environment Agency-Abu Dhabi, PO Box 45553, Abu Dhabi, United Arab Emirates
| | - MA Hesni
- Zoological Museum of Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - A Mancini
- Grupo Tortuguero de las Californias AC, Calle Seis 141, 23098 La Paz, Baja California Sur, Mexico
| | - JD Miller
- Biological Research and Education Consultants, Missoula, Montana 59801, USA
| | - A Mobaraki
- Department of Environmental Sciences, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Hesarak Boulevard, Tehran, Iran
| | - M Rezaie-Atagholipour
- Qeshm Environmental Conservation Institute (QECI), Qeshm Island, Hormozgan Province, Iran
| | - NJ Pilcher
- Marine Research Foundation, 88450 Kota Kinabalu, Sabah, Malaysia
| | - AF Rees
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, Penryn Campus, University of Exeter, Cornwall TR10 9FE, UK
| | - CJ Rodríguez-Zárate
- Sharjah Desert Park, Scientific Research Department, Environment and Protected Areas Authority, Sharjah, United Arab Emirates
| | - DM Smyth
- School of Ocean Science, Marine Centre Wales, Bangor University, Bangor LL59 5AB, UK
| | - LK Tanabe
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - F Yaghmour
- Scientific Research Department, Hefaiyah Mountain Conservation Centre, Environment and Protected Areas Authority, Kalba, Sharjah, United Arab Emirates
| | - AA Yusuf
- Ministry of Fisheries and Marine Resources, Wardhiigley, Mogadishu, Somalia
| | - BJ Godley
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, Penryn Campus, University of Exeter, Cornwall TR10 9FE, UK
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Trevino MA, Dimmick HL, Parra ME, Sterczala AJ, Miller JD, Deckert JA, Gallagher PM, Fry AC, Weir JP, Herda TJ. Effects of continuous cycling training on motor unit firing rates, input excitation, and myosin heavy chain of the vastus lateralis in sedentary females. Exp Brain Res 2022; 240:825-839. [DOI: 10.1007/s00221-021-06278-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 11/13/2021] [Indexed: 11/25/2022]
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10
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Dimmick HL, Trevino MA, Miller JD, Parra ME, Sterczala AJ, Herda TJ. Method of analysis influences interpretations of sex-related differences in firing rates during prolonged submaximal isometric contractions. J Musculoskelet Neuronal Interact 2022; 22:27-36. [PMID: 35234156 PMCID: PMC8919653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study examined motor unit (MU) firing rates during a prolonged isometric contraction of the vastus lateralis (VL) for females and males. METHODS Surface electromyographic (sEMG) signals were recorded from the VL for eleven females and twelve males during a 45-second isometric trapezoid muscle actions at 40% of maximal voluntary contraction (MVC). For each MU, mean firing rate (MFR) was calculated for the initial and final 10-second epochs of the steady torque segment and regressed against recruitment threshold (RT, expressed as %MVC), as well as time at recruitment (TREC, seconds). MFR was also averaged for each subject. RESULTS Significant differences existed across epochs for the y-intercepts (P=0.009) of the MFR vs. TREC relationship, as well as the grouped MFR analysis (P<0.001); no differences were observed between epochs for the MFR vs. RT relationship. Significant differences existed between sexes for the grouped MFR analysis (P=0.049), but no differences were observed for the MFR vs. TREC or MFR vs. RT relationships. CONCLUSION Analysis method may impact interpretation of firing rate behavior; increases in MU firing rates across a prolonged isometric contraction were observed in the MFR vs. TREC relationship and the grouped MFR analysis.
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Affiliation(s)
- Hannah L. Dimmick
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Michael A. Trevino
- Applied Neuromuscular Physiology Laboratory Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA
| | - Jonathan D. Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA
| | - Mandy E. Parra
- Mayborn College of Health Sciences, University of Mary Hardin-Baylor, Belton, TX, USA
| | - Adam J. Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburg, Pittsburgh, PA, USA
| | - Trent J. Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA,Corresponding author: Trent J. Herda, Associate Professor, Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, KS 66045 E-mail:
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Al Ameri HM, Al Harthi S, Al Kiyumi A, Al Sariri TS, Al-Zaidan ASY, Antonopoulou M, Broderick AC, Chatting M, Das HS, Hesni MA, Mancini A, Miller JD, Mobaraki A, Rezaie-Atagholipour M, Pilcher NJ, Rees AF, Rodriguez-Zarate CJ, Smyth DM, Tanabe LK, Yaghmour F, Yusuf AA, Godley BJ. Biology and conservation of marine turtles in the North-Western Indian Ocean: a review. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Parra ME, Miller JD, Sterczala AJ, Kelly MR, Herda TJ. The reliability of the slopes and y-intercepts of the motor unit firing times and action potential waveforms versus recruitment threshold relationships derived from surface electromyography signal decomposition. Eur J Appl Physiol 2021; 121:3389-3398. [PMID: 34477930 DOI: 10.1007/s00421-021-04790-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/12/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Changes in motor unit (MU) activity pre- to post-interventions is of high interest. However, there is minimal information regarding day-to-day changes or the reliability of measuring MU activity. This study examined the reliability of relationships calculated via the MU action potential (AP) trains derived from surface electromyography signal decomposition. A comparison between reliability statistics was made between MUAP trains verified with only the reconstruct-and-test versus verification including reconstruct-and-test with spike trigger average (STA) procedures. METHODS Twenty-one individuals performed isometric muscle actions at 50% of maximal voluntary contraction of the first dorsal interosseous on two separate visits. MUs included for reliability analyses initially met the > 90% accuracy from the reconstruct-and-test. STA was applied as an additional exclusionary procedure. Linear regressions were applied to the firing rate and AP amplitude versus recruitment threshold relationships with and without MUs that met the STA criteria. Reliability statistics were also performed on relationships that met a strict range of recruitment thresholds. Reliability was established with intraclass correlation coefficients (ICC) along with other traditional parameters. RESULTS The firing rate versus recruitment threshold relationships were reliable (ICC > 0.56) and improved (ICC > 0.84) when recruitment ranges were controlled. The slopes of the MUAP amplitude versus recruitment threshold relationships were reliable (ICC > 0.78) while the y-intercepts were reliable (ICC > 0.81) once corrections were made to combat negative scores. CONCLUSIONS Electromyographic signal decomposition without the secondary STA verification procedures can be used to detect intervention-related changes in neural drive with confidence when recorded MU recruitment thresholds are similar across days.
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Affiliation(s)
- Mandy E Parra
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, KS, 66045, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburg, Pittsburgh, PA, USA
| | - Melani R Kelly
- Human Performance Research Laboratory, Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, NE, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, KS, 66045, USA.
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Miller JD, Hermes MJ, Cabarkapa D, Fry AC, Berkland CJ. A Soft 3-dimensional Force Sensor For Measuring Head Impacts In Football Helmets. Med Sci Sports Exerc 2021. [DOI: 10.1249/01.mss.0000760952.41615.a4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Stottlemire BJ, Miller JD, Whitlow J, Huayamares SG, Dhar P, He M, Berkland CJ. Remote Sensing and Remote Actuation via Silicone-Magnetic Nanorod Composites. Adv Mater Technol 2021; 6:2001099. [PMID: 36304209 PMCID: PMC9603773 DOI: 10.1002/admt.202001099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Indexed: 06/16/2023]
Abstract
The capacity for a soft material to combine remote sensing and remote actuation is highly desirable for many applications in soft robotics and wearable technologies. This work presents a silicone elastomer with a suspension of a small weight fraction of ferromagnetic nickel nanorods, which is capable of both sensing deformation and altering stiffness in the presence of an external magnetic field. Cylinders composed of silicone elastomer and 1% by weight nickel nanorods experience large increases in compressive modulus when exposed to an external magnetic field. Incremental compressions totaling 600 g of force applied to the same silicone-nanorod composites increase the magnetic field strength measured by a Hall effect sensor enabling the material to be used as a soft load cell capable of detecting the rate, duration, and magnitude of force applied. In addition, lattice structures are 3D printed using an ink composed of silicone elastomer and 1% by weight nickel nanorods, which possess the same sensing capacity.
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Affiliation(s)
- Bryce J Stottlemire
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA
| | - Jonathan D Miller
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA; Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
| | - Jonathan Whitlow
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA
| | - Sebastian G Huayamares
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA
| | - Prajnaparamita Dhar
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA
| | - Mei He
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA
| | - Cory J Berkland
- Department of Chemical and Petroleum Engineering, University of Kansas, 1530 West 15th Street, Lawrence, KS 66045, USA; Department of Pharmaceutical Chemistry University of Kansas 2095 Constant Avenue, Lawrence, KS 66047, USA
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Miller JD, Lippman JD, Trevino MA, Herda TJ. Neural Drive is Greater for a High-Intensity Contraction Than for Moderate-Intensity Contractions Performed to Fatigue. J Strength Cond Res 2020; 34:3013-3021. [PMID: 33105349 DOI: 10.1519/jsc.0000000000003694] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Miller, JD, Lippman, JD, Trevino, MA, and Herda, TJ. Larger motor units are recruited for high-intensity contractions than for fatiguing moderate-intensity contractions. J Strength Cond Res 34(11): 3013-3021, 2020-The purpose of this study was to investigate whether moderate-intensity contractions performed to fatigue activate the motor unit (MU) pool to the same extent as a higher-intensity contraction. Subjects (7 men, 2 women, age = 22.78 ± 4.15 years, height = 173.78 ± 14.19 cm, mass = 87.39 ± 21.19 kg) performed 3 isometric maximum voluntary contractions (MVCs), an isometric trapezoidal contraction at 90% MVC (REP90), and repetitive isometric trapezoidal contractions at 50% MVC performed to failure with the first (REP1) and final repetition (REPL) used for analysis. Surface EMG was recorded from the vastus lateralis. Action potentials were extracted into firing events of single MUs with recruitment thresholds (RTs), MU action potential amplitudes (MUAPAMP), and mean firing rates (MFRs) recorded. Linear MFR and MUAPAMP vs. RT and exponential MFR vs. MUAPAMP relationships were calculated for each subject. The level of significance was set at p ≤ 0.05. B terms for the MFR vs. MUAPAMP relationships (p = 0.001, REPL = -4.77 ± 1.82 pps·mV, REP90 = -2.63 ± 1.00 pps·mV) and predicted MFRs for MUs recruited at 40% MVC (p < 0.001, REPL = 11.14 ± 3.48 pps, REP90 = 18.38 ± 2.60 pps) were greater for REP90 than REPL indicating firing rates were greater during REP90. In addition, larger mean (p = 0.038, REPL = 0.178 ± 0.0668 mV, REP90 = 0.263 ± 0.128 mV) and maximum (p = 0.008, REPL = 0.320 ± 0.127 mV, Rep90 = 0.520 ± 0.234 mV) MUAPAMPS were recorded during REP90 than REPL. Larger MUs were recruited and similar sized MUs maintained greater firing rates during a high-intensity contraction in comparison to a moderate-intensity contraction performed at fatigue. Individuals seeking maximized activation of the MU pool should use high-intensity resistance training paradigms rather than moderate-intensity to fatigue.
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Affiliation(s)
- Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas; and
| | - Jeremy D Lippman
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas; and
| | - Michael A Trevino
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas; and
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Parra ME, Miller JD, Sterczala AJ, Trevino MA, Dimmick HL, Herda TJ. Differences in the firing rate versus recruitment threshold relationships of the vastus lateralis in children ages 7-10 years and adults. Hum Mov Sci 2020; 72:102650. [PMID: 32721368 DOI: 10.1016/j.humov.2020.102650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 03/18/2020] [Accepted: 05/25/2020] [Indexed: 11/17/2022]
Abstract
Motor unit (MU) firing rates of the vastus lateralis in children and adults were examined. Seven healthy adult males (mean ± SD, age = 21 ± 2.6 yrs) and six healthy male children (mean ± SD age = 8.8 ± 1.7) volunteered. Surface electromyography (EMG) signals were recorded from 20% and 60% maximal voluntary contractions (MVC). Surface EMG signals were decomposed into firing events of individual MUs and slopes and y-intercepts were calculated for the mean firing rate (MFR, pps) at steady torque vs. recruitment thresholds (RT) relationships for each subject. Muscle cross-sectional area (mCSA) was measured, via ultrasonography, with specific torque calculated (MVC/mCSA). Adults possessed greater mCSA (p = .002; children = 11.5 ± 2.1 cm2; adults = 31.80 ± 12.15 cm2) and greater specific torque (p = .018; children = 4.63 ± 1.4 Nm/cm2; adults = 7.1 ± 1.8 Nm/cm2) compared to children. The y-intercepts were significantly (p < .001) greater during the 60% (28.91 ± 4.56 pps) than the 20% MVC (23.5 ± 4.9 pps) collapsed across groups while the children had significantly (p = .036) lower y-intercepts (23.9 ± 5.4 pps) than the adults (28.2 ± 4.8 pps) when collapsed across intensities. Slopes of the MFR vs RT relationships were greater for the 60% (-0.342 ± 0.127 pps/%MVC) contraction than the 20% (-0.50 ± 0.159 pps/%MVC) MVC when collapsed across groups. Adults had greater firing rates regardless of recruitment threshold than children. This may be due to lower recruitment potential and overall excitation to the motoneuron pool of children as indicated with differences in specific torque and/or differences in antagonist co-activation.
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Affiliation(s)
- Mandy E Parra
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael A Trevino
- Applied Neuromuscular Physiology Laboratory Department of Health and Human Performance, Oklahoma State University, Stillwater, OK 74078, USA
| | - Hannah L Dimmick
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA.
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Trevino MA, Sterczala AJ, Miller JD, Parra ME, Dimmick HL, Herda TJ. EFFECTS OF CONTINUOUS CYCLING TRAINING ON MOTOR UNIT BEHAVIOR AND MUSCLE ACTIVATION DURING REPETITIVE CONTRACTIONS. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000685780.40626.ea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Herda TJ, Parra ME, Miller JD, Sterczala AJ, Kelly MR. Measuring the accuracies of motor unit firing times and action potential waveforms derived from surface electromyographic decomposition. J Electromyogr Kinesiol 2020; 52:102421. [PMID: 32353708 DOI: 10.1016/j.jelekin.2020.102421] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 11/25/2022] Open
Abstract
This study included spike trigger averaging (STA) procedures to examine the acceptability of the Precision Decomposition (PD) III derived motor unit action potential (MUAP) trains that met the >90% accuracy criteria from the reconstruct-and-test. MUs met the >90% accuracy criteria from the reconstruct-and-test with STA procedures then applied. Y-intercepts and slopes were calculated for the firing rate- and MUAP amplitude-recruitment threshold relationships. Gaussian noise (1% of the SD of the mean interspike interval) was added to the firing times with the changes in MUAPs quantified. A total of 455 MUs were decomposed with 155 MUs removed as a result of the reconstruct-and-test. Five additional MUs were excluded via the STA criteria. The MUAP waveforms deteriorated with the inclusion of Gaussian noise. There were differences in the derived action potentials amplitudes of higher-threshold MUs between the PD III algorithm and the STA procedure. There was excellent agreement among the slopes and y-intercepts between the relationships that included or excluded MUs that did not meet the STA criteria. There was good agreement between the MUAP amplitude-recruitment threshold relationships derived from the PD III and STA procedure. The addition of the STA procedures did not alter the MU-derived relationships.
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Affiliation(s)
- Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA.
| | - Mandy E Parra
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburg, Pittsburgh, PA, USA
| | - Melani R Kelly
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
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Wallace BP, Stacy BA, Cuevas E, Holyoake C, Lara PH, Marcondes ACJ, Miller JD, Nijkamp H, Pilcher NJ, Robinson I, Rutherford N, Shigenaka G. Oil spills and sea turtles: documented effects and considerations for response and assessment efforts. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Sydenham EW, Shephard GS, Thiel PG, Stockenström S, Snijman PW, Van Schalkwyk DJ, Castegnaro M, Kamimura H, Lauren DR, Miller JD, Nawaz S, Pascale M, Pittet A, Savard ME, Schillack VR, Scudamore K, Sizoo EA, Smith WA, Stack ME, Ueno Y, Viljoen CC, Visconti A, van der Westhuizen L. Liquid Chromatographic Determination of Fumonisins B1, B2, and B3 in Corn: AOAC–IUPAC Collaborative Study. J AOAC Int 2020. [DOI: 10.1093/jaoac/79.3.688] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
A liquid chromatographic (LC) method for simultaneous determination of fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) in corn was subjected to a collaborative study involving 12 participants from 10 countries, in which the accuracy and reproducibility characteristics of the method were established. Mean analyte recoveries from corn ranged from 81.1 to 84.2% for FB1 (at a spiking range of 500 to 8000 ng/g), from 75.9 to 81.9% for FB2 (at a spiking range of 200 to 3200 ng/g), and from 75.8 to 86.8% for FB3 (at a spiking range of 100 to 1600 ng/g). The valid data were statistically evaluated after exclusion of outliers. Relative standard deviations for within-laboratory repeatability ranged from 5.8 to 13.2% for FB1, from 7.2 to 17.5% for FB2, and from 8.0 to 17.2% for FB3. Relative standard deviations for between-laboratory reproducibility varied from 13.9 to 22.2% for FB1, from 15.8 to 26.7% for FB2, and from 19.5 to 24.9% for FB3. HORRAT ratios, calculated for the individual toxin analogues, ranged from 0.75 to 1.73. The LC method for determination of fumonisins B1, B2, and B3 in corn (at concentrations of 800–12800 ng total fumonisins/g) has been adopted by AOAC INTERNATIONAL.
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Affiliation(s)
- Eric W Sydenham
- Medical Research Council, Programme on Mycotoxins and Experimental Carcinogenesis, PO Box 19070, Tygerberg 7505, South Africa
| | - Gordon S Shephard
- Medical Research Council, Programme on Mycotoxins and Experimental Carcinogenesis, PO Box 19070, Tygerberg 7505, South Africa
| | - Pieter G Thiel
- Medical Research Council, Programme on Mycotoxins and Experimental Carcinogenesis, PO Box 19070, Tygerberg 7505, South Africa
| | - Sonja Stockenström
- Medical Research Council, Programme on Mycotoxins and Experimental Carcinogenesis, PO Box 19070, Tygerberg 7505, South Africa
| | - Petra W Snijman
- Medical Research Council, Programme on Mycotoxins and Experimental Carcinogenesis, PO Box 19070, Tygerberg 7505, South Africa
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Herda TJ, Ryan ED, Kohlmeier M, Trevino MA, Gerstner GR, Roelofs EJ, Miller JD. Muscle cross‐sectional area and motor unit properties of the medial gastrocnemius and vastus lateralis in normal weight and overfat children. Exp Physiol 2020; 105:335-346. [DOI: 10.1113/ep088181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/27/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Trent J. Herda
- Neuromechanics LaboratoryUniversity of Kansas Lawrence KS USA
| | - Eric D. Ryan
- Neuromuscular Research LaboratoryDepartment of Exercise Science and Sport ScienceUniversity of North Carolina at Chapel Hill Chapel Hill NC USA
- Human Movement Science CurriculumUniversity of North Carolina at Chapel Hill Chapel Hill NC USA
| | - Martin Kohlmeier
- Department of Nutrition, School of MedicineUniversity of North Carolina at Chapel Hill Chapel Hill NC USA
- Nutrigenetics LaboratoryUniversity of North Carolina at Chapel Hill Kannapolis NC USA
| | - Michael A. Trevino
- Applied Neuromuscular Physiology LaboratoryDepartment of Health and Human PerformanceOklahoma State University Stillwater OK USA
| | - Gena R. Gerstner
- Department of Human Movement SciencesOld Dominion University Norfolk VA USA
| | - Erica J. Roelofs
- School of KinesiologyUniversity of Minnesota Twin Cities Minneapolis MN USA
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Sterczala AJ, Miller JD, Dimmick HL, Wray ME, Trevino MA, Herda TJ. Eight weeks of resistance training increases strength, muscle cross-sectional area and motor unit size, but does not alter firing rates in the vastus lateralis. Eur J Appl Physiol 2019; 120:281-294. [DOI: 10.1007/s00421-019-04273-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/23/2019] [Indexed: 12/11/2022]
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Gungoren C, Ozdemir O, Wang X, Ozkan SG, Miller JD. Effect of ultrasound on bubble-particle interaction in quartz-amine flotation system. Ultrason Sonochem 2019; 52:446-454. [PMID: 30595489 DOI: 10.1016/j.ultsonch.2018.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 05/22/2023]
Abstract
In this study, the effect of ultrasound (US) on the quartz-amine flotation system was investigated in detail by considering various surface chemistry techniques. The effect of ultrasound on particle size, shape factor, and surface roughness were characterized by using Brunauer-Emmett-Teller (BET) surface area measurements and scanning electron microscopy (SEM) analyses. The contact angle and bubble-particle attachment time, as well as adsorption density measurements was carried out to evaluate the effect of ultrasound on quartz surface wetting ability. In addition, atomic force microscopy (AFM) analyses were conducted, and finally micro-flotation studies were performed. As a result, it was found that the micro-flotation recovery at 2 × 10-5 M dodecyl amine hydrochloride (DAH) concentration increased from 45.45% to 63.64% with 30 W ultrasonic application at conditioning step. However, the micro-flotation recovery decreased to 37.50% when the ultrasonic power increased to 150 W. The results showed some effect of ultrasound on particle size, particle shape, and surface roughness in some extent. The increase in the contact angle and the decrease in the bubble-particle attachment time were observed. A slightly high adsorption density was measured. All these show a positive effect of ultrasound on quartz flotation with amine as a collector.
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Affiliation(s)
- C Gungoren
- Istanbul University-Cerrahpasa Engineering Faculty Mining Engineering Department, 34320, Avcilar, Istanbul, Turkey
| | - O Ozdemir
- Istanbul University-Cerrahpasa Engineering Faculty Mining Engineering Department, 34320, Avcilar, Istanbul, Turkey
| | - X Wang
- Department of Metallurgical Engineering, College of Mines and Earth Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - S G Ozkan
- Istanbul University-Cerrahpasa Engineering Faculty Mining Engineering Department, 34320, Avcilar, Istanbul, Turkey.
| | - J D Miller
- Department of Metallurgical Engineering, College of Mines and Earth Sciences, University of Utah, Salt Lake City, UT 84112, USA
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Usategui-Martín A, Liria-Loza A, Miller JD, Medina-Suárez M, Jiménez-Bordón S, Pérez-Mellado V, Montero D. Effects of incubation temperature on hatchling performance and phenotype in loggerhead sea turtle Caretta caretta. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00935] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Wildermann NE, Gredzens C, Avens L, Barrios-Garrido HA, Bell I, Blumenthal J, Bolten AB, Braun McNeill J, Casale P, Di Domenico M, Domit C, Epperly SP, Godfrey MH, Godley BJ, González-Carman V, Hamann M, Hart KM, Ishihara T, Mansfield KL, Metz TL, Miller JD, Pilcher NJ, Read MA, Sasso C, Seminoff JA, Seney EE, Willard AS, Tomás J, Vélez-Rubio GM, Ware M, Williams JL, Wyneken J, Fuentes MMPB. Informing research priorities for immature sea turtles through expert elicitation. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00916] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Dimmick HL, Sterczala AJ, Trevino MA, Richardson HL, Miller JD, Herda TJ. Motor Unit Action Potential Amplitude Vs Recruitment Threshold Relationships In Endurance Runners And Sedentary Females. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536930.52834.01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Miller JD, Sterczala AJ, Wray ME, Dimmick HL, Trevino MA, Herda TJ. Muscle Activation and Motor Unit Behavior in the First Dorsal Interosseous of Children and Adults. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536951.23233.57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Miller JD, Sterczala AJ, Trevino MA, Herda TJ. Examination of muscle composition and motor unit behavior of the first dorsal interosseous of normal and overweight children. J Neurophysiol 2018; 119:1902-1911. [PMID: 29412774 DOI: 10.1152/jn.00675.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We examined differences between normal weight (NW) and overweight (OW) children aged 8–10 yr in strength, muscle composition, and motor unit (MU) behavior of the first dorsal interosseous. Ultrasonography was used to determine muscle cross-sectional area (CSA), subcutaneous fat (sFAT), and echo intensity (EI). MU behavior was assessed during isometric muscle actions at 20% and 50% of maximal voluntary contraction (MVC) by analyzing electromyography amplitude (EMGRMS) and relationships between mean firing rates (MFR), recruitment thresholds (RT), and MU action potential amplitudes (MUAPsize) and durations (MUAPtime). The OW group had significantly greater EI than the NW group ( P = 0.002; NW, 47.99 ± 6.01 AU; OW, 58.90 ± 10.63 AU, where AU is arbitrary units) with no differences between groups for CSA ( P = 0.688) or MVC force ( P = 0.790). MUAPsize was larger for NW than OW in relation to RT ( P = 0.002) and for MUs expressing similar MFRs ( P = 0.011). There were no significant differences ( P = 0.279–0.969) between groups for slopes or y-intercepts from the MFR vs. RT relationships. MUAPtime was larger in OW ( P = 0.015) and EMGRMS was attenuated in OW compared with NW ( P = 0.034); however, there were no significant correlations ( P = 0.133−0.164, r = 0.270−0.291) between sFAT and EMGRMS. In a muscle that does not support body mass, the OW children had smaller MUAPsize as well as greater EI, although anatomical CSA was similar. This contradicts previous studies examining larger limb muscles. Despite evidence of smaller MUs, the OW children had similar isometric strength compared with NW children. NEW & NOTEWORTHY Ultrasound data and motor unit action potential sizes suggest that overweight children have poorer muscle composition and smaller motor units in the first dorsal interosseous than normal weight children. Evidence is presented that suggests differences in action potential size cannot be explained by differences in subcutaneous fat alone.
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Affiliation(s)
- Jonathan D. Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Adam J. Sterczala
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Michael A. Trevino
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Trent J. Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas
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Sterczala AJ, Miller JD, Wray ME, Dimmick HL, Trevino MA, Herda TJ. The Effects of Resistance Training on Motor Unit Firing Rates and Muscle Activation. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536958.05307.c0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wray ME, Sterczala AJ, Miller JD, Dimmick HL, Herda TJ. Sex-Related Differences in Muscle Composition and Motor Unit Firing Rates of the First Dorsal Interosseous. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535111.46582.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fry AC, Housh TJ, Cramer JB, Weir JP, Beck TW, Schilling BK, Miller JD, Nicoll JX. Noninvasive Assessment of Skeletal Muscle Myosin Heavy Chain Expression in Trained and Untrained Men. J Strength Cond Res 2018; 31:2355-2362. [PMID: 28820846 DOI: 10.1519/jsc.0000000000001645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Fry, AC, Housh, TJ, Cramer, JB, Weir, JP, Beck, TW, Schilling, BK, Miller, JD, and Nicoll, JX. Noninvasive assessment of skeletal muscle myosin heavy chain expression in trained and untrained men. J Strength Cond Res 31(9): 2355-2362, 2017-Numerous conditions and types of physical activity (e.g., exercise, aging, and muscle-related diseases) can influence muscle fiber types and the proteins expressed. To date, muscle fibers can only be characterized by actually obtaining a tissue sample using the invasive muscle biopsy procedure. Mechanomyography (MMG) is the assessment of the vibration properties of contracting skeletal muscle and has been proposed as a possible noninvasive method for muscle fiber analysis. Therefore, the purpose of this project was to examine the feasibility of using MMG and muscle performance measures to noninvasively assess muscle fiber characteristics. Fifteen men (5 endurance-trained, 5 weight-trained, and 5 sedentary) provided muscle samples from their vastus lateralis muscle. These samples were analyzed for relative myosin heavy chain (MHC) protein expression, which is highly correlated with % muscle fiber type areas. Additionally, each subject performed several muscle performance tests, and MMG of the quadriceps was assessed during a knee extension exercise. Multiple regression was used to develop prediction equations for determining relative muscle content of MHC types I, IIa, and IIx. A combination of MMG and knee extension performance variables estimated types I, IIa, and IIx MHCs with approximately 80% accuracy. Although preliminary, these data suggest that muscle performance tests in addition to MMG assessments during a simple muscle performance task (knee extension) can be used to estimate muscle fiber type composition in a healthy male population. Such methods could ultimately be used to noninvasively monitor muscle health and fitness.
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Affiliation(s)
- Andrew C Fry
- 1Osness Human Performance Laboratories, Department of Health, Sport & Exercise Sciences, University of Kansas, Lawrence, Kansas; 2Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; 3Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma; and 4Department of Kinesiology and Nutrition Sciences, University of Nevada-Las Vegas, Las Vegas, Nevada
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Sterczala AJ, Miller JD, Trevino MA, Dimmick HL, Herda TJ. Differences in the motor unit firing rates and amplitudes in relation to recruitment thresholds during submaximal contractions of the first dorsal interosseous between chronically resistance-trained and physically active men. Appl Physiol Nutr Metab 2018; 43:759-768. [PMID: 29481763 DOI: 10.1139/apnm-2017-0646] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous investigations report no changes in motor unit (MU) firing rates during submaximal contractions following resistance training. These investigations did not account for MU recruitment or examine firing rates as a function of recruitment threshold (REC). Therefore, MU recruitment and firing rates in chronically resistance-trained (RT) and physically active controls (CON) were examined. Surface electromyography signals were collected from the first dorsal interosseous during isometric muscle actions at 40% and 70% maximal voluntary contraction (MVC). For each MU, force at REC, mean firing rate (MFR) during the steady force, and MU action potential amplitude (MUAPAMP) were analyzed. For each individual and contraction, the MFRs were linearly regressed against REC, whereas, exponential models were applied to the MFR versus MUAPAMP and MUAPAMP versus REC relationships with the y-intercepts and slopes (linear) and A and B terms (exponential) calculated. For the 40% MVC, the RT had less negative slopes (p = 0.001) and lower y-intercepts (p = 0.006) of the MFR versus REC relationships and lower B terms (p = 0.011) of the MUAPAMP versus REC relationships. There were no differences in either relationship between groups for the 70% MVC. During the 40% MVC, the RT had a smaller range of MFRs and MUAPAMPS in comparison with the CON, likely because of reduced MU recruitment. The RT had lower MFRs and recruitment during the 40% MVC, which may indicate a leftward shift in the force-frequency relationship, and thus require less excitation to the motoneuron pool to match the same relative force.
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Affiliation(s)
- Adam J Sterczala
- a Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | - Jonathan D Miller
- a Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | - Michael A Trevino
- b Department of Health Sciences, Armstrong State University, Savannah, GA 31419, USA
| | - Hannah L Dimmick
- a Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | - Trent J Herda
- a Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
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Sterczala AJ, Herda TJ, Miller JD, Ciccone AB, Trevino MA. Age-related differences in the motor unit action potential size in relation to recruitment threshold. Clin Physiol Funct Imaging 2017; 38:610-616. [PMID: 28737276 DOI: 10.1111/cpf.12453] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/15/2017] [Indexed: 11/27/2022]
Abstract
Motor unit action potential size (MUAPsize ) versus recruitment threshold (RT) relationship analysis provides a non-invasive measure of motor unit (MU) hypertrophy; however, this method's ability to identify MU atrophy is unknown. This investigation sought to determine if MUAPsize versus RT relationship slope (APslope ) comparison could identify evidence of MU atrophy in older individuals. Surface electromyography signals were recorded from the first dorsal interosseous (FDI) of fourteen young (YG, age = 22·29 ± 2·79 years) and ten older (OG, 61·0 ± 2·0 years) subjects during a 50% maximal voluntary contraction (MVC) isometric trapezoidal muscle action. The signals were decomposed to yield a MUAPsize and RT for each MU. For each subject, the MUs recruited between 10% and 50% MVC were linearly regressed as a function of RT to calculate an individual APslope . FDI cross-sectional area (CSA) and echo intensity (EI) were quantified via ultrasonography. The mean APslope was lower for OG (0·033 ± 0·010 mV %MVC-1 ) than YG (0·056 ± 0·019 mV %MVC-1 ). OG and YG possessed similar CSAs (OG: 2·09 ± 0·31 cm2 ; YG: 2·08 ± 0·41 cm2 ); however, OG (53·25 ± 7·56 AU) had greater EI than YG (43·87 ± 7·59 AU). The lower OG mean APslope was due to smaller MUAPsizes of higher-threshold MUs, likely due to atrophy of muscle fibres that comprise those MUs. In support, similar CSA with greater EI indicated increased adipose and fibrous tissue and reduced contractile tissue in OG. Thus, MUAPsize versus RT relationship may provide a non-invasive measure of MU atrophy.
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Affiliation(s)
- Adam J Sterczala
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA
| | - Trent J Herda
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA
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Miller JD, Herda TJ, Trevino MA, Sterczala AJ, Ciccone AB. Time-related changes in firing rates are influenced by recruitment threshold and twitch force potentiation in the first dorsal interosseous. Exp Physiol 2017; 102:950-961. [PMID: 28544046 DOI: 10.1113/ep086262] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/18/2017] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? The influences of motor unit recruitment threshold and twitch force potentiation on the changes in firing rates during steady-force muscular contractions are not well understood. What is the main finding and its importance? The behaviour of motor units during steady force was influenced by recruitment threshold, such that firing rates decreased for lower-threshold motor units but increased for higher-threshold motor units. In addition, individuals with greater changes in firing rates possessed greater twitch force potentiation. There are contradictory reports regarding changes in motor unit firing rates during steady-force contractions. Inconsistencies are likely to be the result of previous studies disregarding motor unit recruitment thresholds and not examining firing rates on a subject-by-subject basis. It is hypothesized that firing rates are manipulated by twitch force potentiation during contractions. Therefore, in this study we examined time-related changes in firing rates at steady force in relationship to motor unit recruitment threshold in the first dorsal interosseous and the influence of twitch force potentiation on such changes in young versus aged individuals. Subjects performed a 12 s steady-force contraction at 50% maximal voluntary contraction, with evoked twitches before and after the contraction to quantify potentiation. Firing rates, in relationship to recruitment thresholds, were determined at the beginning, middle and end of the steady force. There were no firing rate changes for aged individuals. For the young, firing rates decreased slightly for lower-threshold motor units but increased for higher-threshold motor units. Twitch force potentiation was greater for young than aged subjects, and changes in firing rates were correlated with twitch force potentiation. Thus, individuals with greater increases in firing rates of higher-threshold motor units and decreases in lower-threshold motor units possessed greater twitch force potentiation. Overall, changes in firing rates during brief steady-force contractions are dependent on recruitment threshold and explained in part by twitch force potentiation. Given that firing rate changes were measured in relationship to recruitment threshold, this study illustrates a more complete view of firing rate changes during steady-force contractions.
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Affiliation(s)
- Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, 66044, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, 66044, USA
| | - Michael A Trevino
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, 66044, USA
| | - Adam J Sterczala
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, 66044, USA
| | - Anthony B Ciccone
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, 66044, USA
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Sterczala AJ, Miller JD, Ciccone AB, Trevino MA, Nicoll JX, Herda TJ. Motor Unit Action Potential Sizes of the First Dorsal Interosseous in Young and Older Individuals. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519825.09707.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Trevino MA, Gallagher PM, Fry AC, Miller JD, Sterczala AJ, Herda TJ. Myosin Heavy Chain Influences Firing Rate Behavior from Moderate to High Intensity Targeted Forces. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519840.55448.b4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Miller JD, Herda TJ, Trevino MA, Sterczala AJ, Ciccone AB. Time-Related Changes in Firing Rate Behavior is Partially Explained by Potentiation. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519739.05254.bb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Miller JD, Herda TJ, Trevino MA, Sterczala AJ, Ciccone AB, Nicoll JX. Age-related differences in twitch properties and muscle activation of the first dorsal interosseous. Clin Neurophysiol 2017; 128:925-934. [PMID: 28402868 DOI: 10.1016/j.clinph.2017.03.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/08/2017] [Accepted: 03/12/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To examine twitch force potentiation and twitch contraction duration, as well as electromyographic amplitude (EMGRMS) and motor unit mean firing rates (MFR) at targeted forces between young and old individuals in the first dorsal interosseous (FDI). Ultrasonography was used to assess muscle quality. METHODS Twenty-two young (YG) (age=22.6±2.7years) and 14 older (OD) (age=62.1±4.7years) individuals completed conditioning contractions at 10% and 50% maximal voluntary contraction, (MVC) during which EMGRMS and MFRs were assessed. Evoked twitches preceded and followed the conditioning contractions. Ultrasound images were taken to quantify muscle quality (cross-sectional area [CSA] and echo intensity [EI]). RESULTS No differences were found between young and old for CSA, pre-conditioning contraction twitch force, or MFRs (P>0.05). However, OD individuals exhibited greater EI and contraction duration (P<0.05), and EMGRMS (YG=35.4±8.7%, OD=43.4±13.2%; P=0.034). Twitch force potentiation was lower for OD (0.311±0.15N) than YG (0.619±0.26N) from pre- to post-50% conditioning contraction (P<0.001). CONCLUSIONS Lower levels of potentiation with elongated contraction durations likely contributed to greater muscle activation during the conditioning contractions in the OD rather than altered MFRs. Ultrasonography suggested age-related changes in muscle structure contributed to altered contractile properties in the OD. SIGNIFICANCE Greater muscle activation requirements can have negative implications on fatigue resistance at low to moderate intensities in older individuals.
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Affiliation(s)
- Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
| | - Michael A Trevino
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
| | - Adam J Sterczala
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
| | - Anthony B Ciccone
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
| | - Justin X Nicoll
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA.
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Mosier EM, Herda TJ, Trevino MA, Miller JD. The influence of prolonged vibration on motor unit behavior. Muscle Nerve 2016; 55:500-507. [PMID: 27465016 DOI: 10.1002/mus.25270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 07/13/2016] [Accepted: 07/26/2016] [Indexed: 11/12/2022]
Abstract
INTRODUCTION The purpose of this study was to determine the effects of vibration (VIB) on motor unit (MU) behavior of the vastus lateralis (VL) muscle during a 40% maximal voluntary contraction (MVC). METHODS Eleven healthy (age 21.3 ± 2.6 years) individuals participated in the study. Surface electromyography (EMG) data were recorded from the VL during isometric trapezoidal muscle contractions at 40% MVC. Firing events of single MUs and EMG amplitude were reported for the first, middle, and final seconds of a 12-second steady force segment at 40% MVC. VIB was applied at 55 Hz to the patellar tendon for 15 minutes before and continued throughout the remainder of testing (VIB) or remained off (CON). RESULTS There were significant increases in MU firing rates during VIB in comparison to CON and no differences in EMG amplitude between VIB and CON. CONCLUSION The VIB-mediated reduction in muscle spindle function altered MU behavior at 40% MVC. Muscle Nerve 55: 500-507, 2017.
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Affiliation(s)
- Eric M Mosier
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Lawrence, Kansas, 66045, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Lawrence, Kansas, 66045, USA
| | - Michael A Trevino
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Lawrence, Kansas, 66045, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Lawrence, Kansas, 66045, USA
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Martin JR, Bonafede MM, Nelson JK, Booth AJ, Miller JD. Treatment Patterns Among Women with Newly Diagnosed Abnormal Uterine Bleeding. J Minim Invasive Gynecol 2016. [DOI: 10.1016/j.jmig.2016.08.235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Miller JD, Herda TJ, Trevino MA, Mosier EM. The effects of passive stretching plus vibration on strength and activation of the plantar flexors. Appl Physiol Nutr Metab 2016; 41:917-23. [DOI: 10.1139/apnm-2016-0010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effects of passive stretching only (PS+CON) and passive stretching with the addition of continuous vibration (VIB) during post-passive stretching tests (PS+VIB) on peak torque (PT), percent voluntary inactivation (%VI), single stimulus twitch torque (TTSINGLE), and doublet stimuli twitch torque (TTDOUBLET) of the plantar flexors at a short (20° plantar flexion (PF)) and long muscle length (15° dorsiflexion (DF)). Fourteen healthy men (age = 22 ± 3 years) performed isometric maximal voluntary contractions at PF and DF, and passive range of motion (PROM) assessments before and after 8 × 30-s passive stretches without (PS+CON) or with VIB (PS+VIB) administered continuously throughout post-passive stretching tests. The passive properties of the muscle tendon unit were assessed pre- and post-passive stretching via PROM, passive torque (PASSTQ), and musculotendinous stiffness (MTS) measurements. PT, TTSINGLE, and TTDOUBLET decreased, whereas, %VI increased following passive stretching at PF and DF (P < 0.05) with no significant differences between PS+CON and PS+VIB. PASSTQ and MTS decreased while PROM increased post-passive stretching during both trials (P < 0.05). The stretching-induced force/torque deficit and increases in %VI were evident following passive stretching at short and long muscle lengths. Although not statistically significant, effect size calculations suggested large and moderate differences in the absolute changes in PT (Cohen’s d = 1.14) and %VI (Cohen’s d = 0.54) from pre- to post-passive stretching between treatments, with PS+VIB having greater decreases of PT and higher %VI than PS+CON. The decrement in PT following passive stretching may be primarily neural in origin.
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Affiliation(s)
- Jonathan D. Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
| | - Trent J. Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
| | - Michael A. Trevino
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
| | - Eric M. Mosier
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS 66044, USA
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Trevino MA, Herda TJ, Fry AC, Gallagher PM, Vardiman JP, Mosier EM, Miller JD. Influence of the contractile properties of muscle on motor unit firing rates during a moderate-intensity contraction in vivo. J Neurophysiol 2016; 116:552-62. [PMID: 27146989 PMCID: PMC4978784 DOI: 10.1152/jn.01021.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/02/2016] [Indexed: 11/22/2022] Open
Abstract
It is suggested that firing rate characteristics of motor units (MUs) are influenced by the physical properties of the muscle. However, no study has correlated MU firing rates at recruitment, targeted force, or derecruitment with the contractile properties of the muscle in vivo. Twelve participants (age = 20.67 ± 2.35 yr) performed a 40% isometric maximal voluntary contraction of the leg extensors that included linearly increasing, steady force, and decreasing segments. Muscle biopsies were collected with myosin heavy chain (MHC) content quantified, and surface electromyography (EMG) was recorded from the vastus lateralis. The EMG signal was decomposed into the firing events of single MUs. Slopes and y-intercepts were calculated for 1) firing rates at recruitment vs. recruitment threshold, 2) mean firing rates at steady force vs. recruitment threshold, and 3) firing rates at derecruitment vs. derecruitment threshold relationships for each subject. Correlations among type I %MHC isoform content and the slopes and y-intercepts from the three relationships were examined. Type I %MHC isoform content was correlated with MU firing rates at recruitment (y-intercepts: r = -0.577; slopes: r = 0.741) and targeted force (slopes: r = 0.853) vs. recruitment threshold and MU firing rates at derecruitment (y-intercept: r = -0.597; slopes: r = 0.701) vs. derecruitment threshold relationships. However, the majority of the individual MU firing rates vs. recruitment and derecruitment relationships were not significant (P > 0.05) and, thus, revealed no systematic pattern. In contrast, MU firing rates during the steady force demonstrated a systematic pattern with higher firing rates for the lower- than higher-threshold MUs and were correlated with the physical properties of MUs in vivo.
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Affiliation(s)
| | - Trent J Herda
- Neuromechanics Laboratory, University of Kansas, Lawrence, Kansas;
| | - Andrew C Fry
- Applied Physiology Laboratory, University of Kansas, Lawrence, Kansas; and
| | - Philip M Gallagher
- Applied Physiology Laboratory, University of Kansas, Lawrence, Kansas; and
| | - John P Vardiman
- Applied Physiology and Sports Medicine Laboratory, Kansas State University, Manhattan, Kansas
| | - Eric M Mosier
- Neuromechanics Laboratory, University of Kansas, Lawrence, Kansas
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Trevino MA, Mosier EM, Miller JD, Fry AC, Gallagher PM, Vardiman JP, Herda TJ. Type I Myosin Heavy Chain Expression Influences Motor Unit Behavior of the Vastus Lateralis. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000486223.33390.a0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Trevino MA, Herda TJ, Fry AC, Gallagher PM, Vardiman JP, Mosier EM, Miller JD. The influence of myosin heavy chain isoform content on mechanical behavior of the vastus lateralis in vivo. J Electromyogr Kinesiol 2016; 28:143-51. [PMID: 27152756 DOI: 10.1016/j.jelekin.2016.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 04/07/2016] [Accepted: 04/12/2016] [Indexed: 11/29/2022] Open
Abstract
This study examined correlations between type I percent myosin heavy chain isoform content (%MHC) and mechanomyographic amplitude (MMGRMS) during isometric muscle actions. Fifteen (age=21.63±2.39) participants performed 40% and 70% maximal voluntary contractions (MVC) of the leg extensors that included increasing, steady force, and decreasing segments. Muscle biopsies were collected and MMG was recorded from the vastus lateralis. Linear regressions were fit to the natural-log transformed MMGRMS-force relationships (increasing and decreasing segments) and MMGRMS was selected at the targeted force level during the steady force segment. Correlations were calculated among type I%MHC and the b (slopes) terms from the MMGRMS-force relationships and MMGRMS at the targeted force. For the 40% MVC, correlations were significant (P<0.02) between type I%MHC and the b terms from the increasing (r=-0.804) and decreasing (r=-0.568) segments, and MMGRMS from the steady force segment (r=-0.606). Type I%MHC was only correlated with MMGRMS during the steady force segment (P=0.044, r=-0.525) during the 70% MVC. Higher type I%MHC reduced acceleration in MMGRMS (b terms) during the 40% MVC and the amplitude during the steady force segments. The surface MMG signal recorded during a moderate intensity contraction provided insight on the contractile properties of the VL in vivo.
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Affiliation(s)
- Michael A Trevino
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, United States.
| | - Trent J Herda
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, United States.
| | - Andrew C Fry
- Applied Physiology Laboratory, University of Kansas, Lawrence, KS, United States.
| | - Philip M Gallagher
- Applied Physiology Laboratory, University of Kansas, Lawrence, KS, United States.
| | - John P Vardiman
- Applied Physiology and Sports Medicine Laboratory, Kansas State University, Manhattan, KS, United States.
| | - Eric M Mosier
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, United States.
| | - Jonathan D Miller
- Neuromechanics Laboratory, University of Kansas, Lawrence, KS, United States.
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Patel FB, Couch KS, McNish S, Miller JD, Siegel R, Easley S, Shanmugam VK. A 66-Year-Old Woman With Hemoptysis. Arthritis Care Res (Hoboken) 2015; 69:439-448. [PMID: 26714016 DOI: 10.1002/acr.22820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 12/02/2015] [Accepted: 12/15/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Falin B Patel
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Kara S Couch
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Sean McNish
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Jonathan D Miller
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Robert Siegel
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Samantha Easley
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
| | - Victoria K Shanmugam
- The George Washington University, School of Medicine and Health Sciences, Washington, DC
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Miller JD, Higgins GL. Images in emergency medicine. Infant with rash. Neonatal Lyme disease. Ann Emerg Med 2015; 64:559, 574. [PMID: 25669704 DOI: 10.1016/j.annemergmed.2014.02.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/14/2014] [Accepted: 02/18/2014] [Indexed: 11/19/2022]
Affiliation(s)
- Jonathan D Miller
- Department of Emergency Medicine, Maine Medical Center, Portland, ME
| | - George L Higgins
- Department of Emergency Medicine, Maine Medical Center, Portland, ME
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Basinski C, Lukes A, Miller JD, Lenhart G, Bonafede M, Troeger K. Treatment Complication and Reintervention Rates Following Endometrial Ablation with the NovaSure® System Versus Other Global Endometrial Ablation Modalities. J Minim Invasive Gynecol 2014. [DOI: 10.1016/j.jmig.2014.08.221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Desroches TC, McMullin DR, Miller JD. Extrolites of Wallemia sebi, a very common fungus in the built environment. Indoor Air 2014; 24:533-542. [PMID: 24471934 DOI: 10.1111/ina.12100] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/21/2014] [Indexed: 06/03/2023]
Abstract
Wallemia sebi has been primarily known as a spoilage fungus of dried, salted fish and other foods that are salty or sweet. However, this fungus is also very common in house dust. The health effects of chronic exposure to mold and dampness are known to be associated with both allergens and various inflammatory compounds, including the secondary metabolites of building associated fungi and their allergens. IgE sensitization to W. sebi has been long reported from housing and occupational exposures. However, its allergens have not been described previously. Strains from food have been reported to produce a number of compounds with modest toxicity. Strains from the built environment in Canada produced a number of metabolites including the known compound walleminone and a new compound 1-benzylhexahydroimidazo [1,5-α] pyridine-3,5-dione which we call wallimidione. Based on an in silico analysis, wallimidione is likely the most toxic of the metabolites reported to date from W. sebi. We found that the primary human antigen of W. sebi is a 47 kDa excreted cellulase present in high concentrations in W. sebi arthrospores. This species is a basidiomycete and, unsurprisingly, the antigen was not found in extracts of other fungi common in the built environment, all ascomycetes.
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Affiliation(s)
- T C Desroches
- Ottawa Carleton Institute of Chemistry, Carleton University, Ottawa, ON, Canada
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Rand TG, Robbins C, Rajaraman D, Sun M, Miller JD. Induction of Dectin-1 and asthma-associated signal transduction pathways in RAW 264.7 cells by a triple-helical (1, 3)-β-D glucan, curdlan. Arch Toxicol 2013; 87:1841-50. [PMID: 23543010 DOI: 10.1007/s00204-013-1042-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 03/08/2013] [Indexed: 11/25/2022]
Abstract
People living in damp buildings are typically exposed to spore and mycelial fragments of the fungi that grow on damp building materials. There is experimental evidence that this exposure to triple-helical (1, 3)-β-D glucan and low molecular weight toxins may be associated with non-atopic asthma observed in damp and moldy buildings. However, the mechanisms underlying this response are only partially resolved. Using the pure (1, 3)-β-D glucan, curdlan, and the murine macrophage cell line, RAW 264.7, there were two objectives of this study. The first was to determine whether signal transduction pathways activating asthma-associated cell signaling pathways were stimulated using mouse transduction Pathway Finder(®) arrays and quantitative real-time (QRT) PCR. The second objective was to evaluate the dose and temporal responses associated with transcriptional changes in asthma-associated cytokines, the signal transduction receptor gene Dectin-1, and various transcription factor genes related to the induction of asthma using customized RT-PCR-based arrays. Compared to controls, the 10(-7) M curdlan treatment induced significant changes in gene transcription predominately in the NFkB, TGF-β, p53, JAK/STAT, P13/AKT, phospholipase C, and stress signaling pathways. The 10(-8) M curdlan treatment mainly induced NFkB and TGF-β pathways. Compared to controls, curdlan exposures also induced significant dose- and time-dependent changes in the gene translations. We found that that curdlan as a non-allergenic potentiator modulates a network of transduction signaling pathways not only associated with TH-1, TH-2, and TH-3 cell responses including asthma potentiation, but a variety of other cell responses in RAW 264.7 cells. These results help provide mechanistic basis for some of the phenotypic changes associated with asthma that have been observed in in vitro, in vivo, and human studies and open up a hypothesis-building process that could explain the rise of non-atopic asthma associated with fungi.
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Affiliation(s)
- Thomas G Rand
- Department of Biology, Saint Mary's University, 923 Robie St, Halifax, NS, B3H 3C3, Canada,
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Miller JD, Skinner CN, Safford HD, Knapp EE, Ramirez CM. Trends and causes of severity, size, and number of fires in northwestern California, USA. Ecol Appl 2012; 22:184-203. [PMID: 22471083 DOI: 10.1890/10-2108.1] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Research in the last several years has indicated that fire size and frequency are on the rise in western U.S. forests. Although fire size and frequency are important, they do not necessarily scale with ecosystem effects of fire, as different ecosystems have different ecological and evolutionary relationships with fire. Our study assessed trends and patterns in fire size and frequency from 1910 to 2008 (all fires > 40 ha), and the percentage of high-severity in fires from 1987 to 2008 (all fires > 400 ha) on the four national forests of northwestern California. During 1910-2008, mean and maximum fire size and total annual area burned increased, but we found no temporal trend in the percentage of high-severity fire during 1987-2008. The time series of severity data was strongly influenced by four years with region-wide lightning events that burned huge areas at primarily low-moderate severity. Regional fire rotation reached a high of 974 years in 1984 and fell to 95 years by 2008. The percentage of high-severity fire in conifer-dominated forests was generally higher in areas dominated by smaller-diameter trees than in areas with larger-diameter trees. For Douglas-fir forests, the percentage of high-severity fire did not differ significantly between areas that re-burned and areas that only burned once (10% vs. 9%) when re-burned within 30 years. Percentage of high-severity fire decreased to 5% when intervals between first and second fires were > 30 years. In contrast, in both mixed-conifer and fir/high-elevation conifer forests, the percentage of high-severity fire was less when re-burned within 30 years compared to first-time burned (12% vs. 16% for mixed conifer; 11% vs. 19% for fir/high-elevation conifer). Additionally, the percentage of high-severity fire did not differ whether the re-burn interval was less than or greater than 30 years. Years with larger fires and greatest area burned were produced by region-wide lightning events, and characterized by less winter and spring precipitation than years dominated by smaller human-ignited fires. Overall percentage of high-severity fire was generally less in years characterized by these region-wide lightning events. Our results suggest that, under certain conditions, wildfires could be more extensively used to achieve ecological and management objectives in northwestern California.
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Affiliation(s)
- J D Miller
- USDA Forest Service, Pacific Southwest Region, Fire and Aviation Management, 3237 Peacekeeper Way, Suite 101, McClellan, California 95652, USA.
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