We assessed the time delay from the onset of QRS (Q) to peak systolic (S') and diastolic (E') tissue velocities in the left (LV) and right ventricle (RV) before and after prolonged exercise. Nineteen well-trained runners (mean +/- SD age, 41 +/- 9 years) had tissue-Doppler echocardiography performed before and after an 89 km ultra-marathon race. Longitudinal tissue motion was analysed in LV basal and mid-wall segments and RV free wall. Electromechanical coupling was assessed by the delay between Q and S' as well as E' tissue velocities. Average data for all segments were adjusted for the R-R interval. Comparisons were made by paired t-tests. An increase in electro-mechanical delay (EMD) was reported post-exercise in systole (Q-S' LV: 131 +/- 20 vs. 175 +/- 27 ms; RV: 171 +/- 34 vs. 258 +/- 35 ms; P < 0.05) and diastole (Q-E' LV: 486 +/- 51 vs. 647 +/- 44 ms; RV: 500 +/- 80 vs. 690 +/- 75 ms; P < 0.05). Further, post-race peak tissue velocities in basal LV and RV wall segments were reduced (P < 0.05). Recovery from prolonged running was associated with an increased "EMD", and reduced peak tissue velocities, in both ventricles.
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http://dx.doi.org/10.1007/s00421-009-1264-6 | DOI Listing |
J Arthroplasty
January 2025
The University of Tennessee Health Science Center-Campbell Clinic Department of Orthopaedic Surgery and Biomedical Engineering, 1400 S. Germantown Rd, Germantown, TN, 38138. Electronic address:
Background: This study investigated the influence of surgical alignment techniques on knee joint biomechanics during stair negotiation tasks. Our hypothesis was that a more personalized joint alignment would result in reduced medial knee loading biomechanics to negotiate the stairs.
Methods: There were 28 adults (14 mechanical alignments [MA], 14 kinematic alignment [KA]) who underwent total knee arthroplasty (TKA) at least one year post-operatively and performed five stair ascent and descent trials at their preferred velocities.
Pharmaceutics
January 2025
Department of Mathematics, Visva-Bharati University, Santiniketan 731235, WB, India.
Microneedle(MN)-based drug delivery is one of the potential approaches to overcome the limitations of oral and hypodermic needle delivery. An in silico model has been developed for hollow microneedle (HMN)-based drug delivery in the skin and its subsequent absorption in the blood and tissue compartments in the presence of interstitial flow. The drug's reversible specific saturable binding to its receptors and the kinetics of reversible absorption across the blood and tissue compartments have been taken into account.
View Article and Find Full Text PDFBeijing Da Xue Xue Bao Yi Xue Ban
February 2025
Department of General Dentistry, Peking University School and Hospital of Stomatology & National Center for Stomato-logy & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China.
Objective: The triply periodic minimal surface (TPMS) Gyroid porous scaffolds were built with identical porosity while varying pore sizes were used by fluid mechanics finite element analysis (FEA) to simulate the microenvironment. The effects of scaffolds with different pore sizes on cell adhesion, proliferation, and osteogenic differentiation were evaluated through calculating fluid velocity, wall shear stress, and permeability in the scaffolds.
Methods: Three types of gyroid porous scaffolds, with pore sizes of 400, 600 and 800 μm, were established by nTopology software.
PLoS One
January 2025
Faculty of Veterinary Medicine, Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland.
Sport-related injuries have been reported to occur in around one-third of agility dogs. Higher bar height in competitions has been shown to increase odds of an injury. This study evaluated the effect of bar height on the kinetics and kinematics at take-off to a bar jump.
View Article and Find Full Text PDFBioact Mater
April 2025
Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, PR China.
Bioelectrical stimulation is a powerful technique used to promote tissue regeneration, but it can be hindered by an "electrical overload" phenomenon in the core region of stimulation. We develop a threaded microneedle electrode system that protects against "electrical overload" by delivering medicinal hydrogel microspheres into the core regions. The threaded needle body is coated with polydopamine and chitosan to enhance the adhesion of microspheres, which are loaded into the threaded grooves, allowing for their stereoscopic release in the core regions.
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