As an excellent model material for fundamental studies on temperature-sensitive hydrogels, poly(-isopropylacrylamide) (NIPA) hydrogel has been applied in drug delivery, tissue engineering, and soft robotics. However, the lack of study on fracture and fatigue hinders further development of hydrogels for applications where cyclic loading-unloading is unavoidable. In this study, the fracture and fatigue damage of the NIPA hydrogel were studied for the first time by pure shear tests at different temperatures. Fracture behaviors were investigated under monotonic load from 31 °C to 39 °C. It is found that the fracture energy increases with the increase in temperature. The fracture energy is approximately 20 J m near the volume phase transition temperature. Temperature also significantly influences the fatigue life. By fitting the experimental data, the fatigue limit is determined. The results obtained from the experimental tests would be important for the engineering applications of the NIPA hydrogels.
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http://dx.doi.org/10.1039/c8ra06518g | DOI Listing |
Geriatr Nurs
December 2024
Department of Management, Policy and Community Health, School of Public Health, The University of Texas Health Science Center at Houston, Houston 77030, Texas, United States. Electronic address:
Objectives: To compare the total medical costs associated with operative versus non-operative medical procedures for femoral neck fractures in older adults with Alzheimer's disease (AD).
Methods: This retrospective cohort study examined 4,157 Optum beneficiaries diagnosed with AD who filed an initial claim for femoral neck fracture between January 1, 2012, and December 31, 2017. Generalized linear regression with Gamma log link function was performed to evaluate total medical costs between surgical treatment and non-operative care while controlling for covariates.
Fatigue cracking of rib-to-deck conventional single-sided welded joints is a prevalent issue in orthotropic steel decks (OSDs), significantly impacting their structural integrity and durability. Rib-to-deck innovative double-sided welded joints have the potential to enhance the fatigue resistance of OSD. However, Welding Residual Stresses (WRS) significantly influence the fatigue life of these joints, mandating its consideration in fatigue assessments.
View Article and Find Full Text PDFBMC Oral Health
December 2024
Department of Conservative Dentistry, Faculty of Dentistry, Minia University, Minia, Egypt.
Objectives: To compare the mechanical performance of partially replaced (repaired) intra-coronal restorations to totally replaced ones in root canal-treated teeth.
Methods: Thirty maxillary second premolars were selected according to strict criteria, mounted on moulds, and had mesio-occluso-distal (MOD) cavities prepared. Resin composite restorative material was used to perform the initial restoration, followed by aging procedures using thermo-mechanical cycling fatigue to replicate six months of intraoral aging.
J Endod
December 2024
Department of Endodontics, Fluminense Federal University, Niteroi.
Introduction: This study aimed to evaluate the mechanical properties of Reciproc, Reciproc Blue, One RECI, and R-Motion, specifically focusing on their flexibility and buckling resistance; and to assess their torsional fatigue behavior under two different reciprocation angles (150°/30° or 70°/30°).
Methods: A total of 160 instruments (40 per brand) were tested. Flexion and buckling tests were conducted using a Universal testing machine (DL 200MF) was used.
J Clin Endocrinol Metab
December 2024
Department of Health Research Methods, Evidence, and Impact, McMaster University.
Objective: To examine the highest certainty evidence addressing the management of X-linked hypophosphatemia (XLH) in adults to inform treatment recommendations.
Methods: We searched Embase, MEDLINE, Web of Science, and Cochrane Central up to May 2023. Eligible studies included RCTs and observational studies of individuals 18+ with clinically or genetically confirmed XLH.
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