Using load-suspended backpacks to reduce vertical peak dynamic load exerted on humans can reduce metabolic costs. However, is it possible to further reduce metabolic cost by modulating dynamic load phase shift? If so, is anti-phase better than the others? In this study, we investigated the biomechanics, energetics and trunk response under phase shifts. Nine subjects wearing an active backpack with 19.4 kg loads walked on a treadmill at 5 km h with four phase shift trials (T1-T4) and a load-locked trial (LK). Our results show that anti-phase trial (T3) assists ankle more and reduces the moment and gastrocnemius medialis activity, while T4 assists knee more and reduces the moment and rectus femoris activity. Due to the load injecting more mechanical energy into human in T3 and T4, the positive centre-of-mass work is significantly reduced. However, the gross metabolic rate is lowest in T4 and 4.43% lower than in T2, which may be because the activations of erector spinae and gluteus maximus are reduced in T4. In addition, T3 increases trunk extensor effort, which may weaken the metabolic advantage. This study provides guidance for improving assistance strategies and human-load interfaces and deepens the understanding of the energetics and biomechanics of human loaded walking.
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http://dx.doi.org/10.1098/rsos.230636 | DOI Listing |
ISA Trans
January 2025
Tenaga Nasional Berhad - Distribution, Kuala Lumpur, Selangor, Malaysia. Electronic address:
As global interest grows in renewable energy sources, the impact of combined Electric Vehicle (EV) and PhotoVoltaic (PV) penetration on the power grid stability requires renewed attention, to incorporate new technologies to maintain the power quality under operational constraints. Energy-saving techniques such as Conservation Voltage Reduction (CVR) allow the power utilities to transmit voltage at a lower operation limit, increasing the generation margin to absorb the peak load demands. Increased reverse PV penetration results in grid overvoltage while EV charging absorbs the reactive power causing grid instability.
View Article and Find Full Text PDFAdv Mater
January 2025
School of Physics, Chongqing University, Chongqing, 400044, P. R. China.
The effective collection of interfacial tribo-charges and an increase in load voltage are two essential factors that improve the output energy of triboelectric nanogenerators. However, some tribo-charges are hardly collected through one or multiple integrated side electrodes based on corona discharge, and their load voltages are limited by air breakdown in adjacent electrodes. In this study, a dynamic quasi-dipole potential distribution model is proposed to systematically reveal the mechanisms of interfacial tribo-charge loss.
View Article and Find Full Text PDFSci Rep
January 2025
ENET Centre, CEET, VSB-Technical University of Ostrava, 708 00, Ostrava, Czech Republic.
Load frequency control (LFC) is critical for maintaining stability in interconnected power systems, addressing frequency deviations and tie-line power fluctuations due to system disturbances. Existing methods often face challenges, including limited robustness, poor adaptability to dynamic conditions, and early convergence in optimization. This paper introduces a novel application of the sinh cosh optimizer (SCHO) to design proportional-integral (PI) controllers for a hybrid photovoltaic (PV) and thermal generator-based two-area power system.
View Article and Find Full Text PDFAm J Cardiovasc Dis
December 2024
Department of Cardiovascular Surgery, School of Medicine, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences Tehran, Iran.
Objectives: Postoperative pulmonary complications (POPC) are common after cardiac surgeries such as coronary artery bypass grafting (CABG) and are influenced by factors including anesthesia and surgical trauma. Inspiratory muscle training (IMT) with visual biofeedback may mitigate these complications. This study investigates the impact of threshold loading inspiratory muscle training (TL-IMT) combined with respiratory biofeedback on the dynamic strength of inspiratory muscles (S-index) in patients undergoing CABG surgery during their hospitalization phase.
View Article and Find Full Text PDFNat Plants
January 2025
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
Arabidopsis PHOSPHATE 1 (AtPHO1) and its closest homologue AtPHO1;H1 are phosphate transporters that load phosphate into the xylem vessel for root-to-shoot translocation. AtPHO1 and AtPHO1;H1 are prototypical members of the unique SPX-EXS family, whose structural and molecular mechanisms remain elusive. In this study, we determined the cryogenic electron microscopy structure of AtPHO1;H1 binding with inorganic phosphate (Pi) and inositol hexakisphosphate in a closed conformation.
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