Unlabelled: QUS measurements were made on 4139 female Army recruits at the beginning of basic training (BT). QUS predicted stress fracture in female recruits as well as it predicts hip fracture in elderly women. Recruits with low QUS values and a history of smoking and not exercising had an extremely high risk of stress fracture.
Introduction: Stress fractures during basic military training (BT) cause morbidity for the recruits and expense for the Military Services. Females have a higher incidence than males. If recruits at high risk for stress fracture could be accurately identified before they began BT, the military might find it advantageous to provide adaptive training programs for them. Currently no accurate methods of risk identification are available. We measured quantitative ultrasound (QUS) in a population sample of female Army recruits to determine if QUS is a useful tool for determining soldiers at high risk of stress fracture during BT.
Materials And Methods: We recruited 93% of the population of female recruits entering BT at Fort Leonard Wood, MO, during a 10-month period. We measured calcaneal QUS and administered a risk factor questionnaire at baseline and ascertained stress fractures during the 8 weeks of BT. Logistic regression was used to calculate relative risk (RR) of stress fracture. The area under the receiver-operating characteristic (ROC) curve was also analyzed to determine the sensitivity and specificity of speed of sound (SOS) in predicting stress fracture.
Results: The incidence of stress fracture was 4.7%. SOS was significantly related to the risk of stress fracture. (p < 0.000) The area under the ROC curve was 0.70. The relative risk (RR) of fracture of those in the lowest quintile (Q1) of SOS was 6.7. The highest risk of stress fracture was found in the subgroup of white women in Q1 of SOS who smoked and didn't exercise (RR, 14.4). Over 16% of the fractures occurred in this subgroup, which indicates that about six of these women would need to be assigned to an alternate BT regimen to prevent one stress fracture.
Conclusions: The combination of QUS measurements with evaluation of individual risk factors can identify recruits who are at the very highest risk of stress fracture. The military may find these data helpful to determine the cost-effectiveness of alternate BT regimens.
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http://dx.doi.org/10.1359/JBMR.041208 | DOI Listing |
Sci Rep
January 2025
College of Petroleum Engineering, Liaoning Petrochemical University, Fushun, China.
The laminae of varying lithologies are characteristic of shale oil reservoirs, with their pronounced heterogeneity and fluid-solid coupling significantly impacting oil productivity. To this end, this study initially quantified the permeability and mechanical heterogeneity in lamina-developed shale through permeability tests and quasi triaxial mechanical experiments on shale cores from different orientations in the Jiyang Depression. These tests revealed marked brittleness in horizontally oriented cores and elasticity in vertically oriented cores.
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January 2025
Laboratoire Sciences et Ingénierie de la Matiére Molle, ESPCI Paris, CNRS, PSL University, Paris, France.
Stretchable elastic materials with high strength, toughness, and good ionic conductivity are highly desirable for wearable devices and stretchable batteries. Unfortunately, limited success has been reported to attain all of these properties simultaneously. Here, we report a family of ionically conductive elastomers (ICEs) without compromise between mechanical properties (high stiffness, reversible elasticity, fracture resistance) and ionic conductivity, by introducing a multiple network elastomer (MNE) architecture into a low polymer.
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December 2024
Prosthodontics and Implantology, Amrita School of Dentistry, Amrita Vishwa Vidyapeetham, Kochi, IND.
Purpose: Acrylic dentures fabricated using polymethyl methacrylate are subjected to either intraoral fatigue stress or extraoral impact stress, eventually forming microcracks and fractures. This limitation should be overcome by either modification in the acrylic resin material or in polymerization techniques. This study compares the impact strength and flexural strength of high-impact resin to conventional resin in short- and long-heat polymerization settings.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Mechanics, Electrical Power and Computer, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Dissimilar laser welding of martensitic AISI 1060 carbon steel and Duplex Stainless Steel 2205 was performed based on an experimental and numerical study. The experiments were then conducted based on central composite design experiments (CCD) and analyzed via the response surface methodology (RSM) by considering the effect of laser welding process parameters (incident laser power, speed of welding, nozzle distance and deviation of laser beam) on the weld joint characterization. The experimental results showed that the laser power had a remarkable effect on the melt pool depth.
View Article and Find Full Text PDFiScience
January 2025
Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Impaired bone quality and increased fracture risk are cardinal features of the skeleton in diabetes mellitus. Hyperglycemia-induced oxidative stress is proposed as a potential underlying mechanism, but the precise pathogenic mechanism remains incompletely understood. In this investigation, osteoblasts under high glucose exhibited heightened levels of reactive oxygen species, impaired mitochondrial membrane potential, and profound inhibition of late-stage osteoblast differentiation.
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