Objective: The goal of this investigation was to assess validity of predictive models of stress relaxation in dental polymers when applied to extended master curves generated from short time experimental data by WLF time temperature superposition method.
Methods: The stress relaxation modulus changes with time at three different temperatures near the ambient body temperature were determined for selected mono-methacrylate (PEMA and PMMA) and dimethacrylate (bis-acryl) dental polymers. WLF time-temperature superposition procedure of logarithmic shift of the data from other temperatures to those at 37°C was used to generate extended master curves of relaxation modulus changes with time. The extended data were analyzed for conformity to three different predictive models of stress relaxation including Maxwell, KWW stretched exponential function and Nutting's power law equation.
Results: Maxwell model was found to be a poor fit for the extended data in all polymers tested, but the data showed a much better fit for KWW (0.870
Significance: The mean values of β in KWW function and power exponent n in Nutting's equation for PEMA resin is consistent with significant viscoplastic contribution to its deformation under stress unlike in PMMA and bis-acryl resin systems. This may have significant bearing for PEMA use in medium to longer term stress-bearing applications even as a temporization material.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.dental.2015.04.002 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Meditation and guided imagery show reduction in chronic stress and increase in mental health-related quality of life for college students.
J Am Coll Health
January 2025
Counseling and Human Servies Department, University of Scranton, Scranton, Pennsylvania, USA.
To explore the effects of guided imagery with progressive deep muscle relaxation (PDMR) and meditation programs on chronic stress perception and health related quality of life in college students. College students were recruited from a local private university in Northeast Pennsylvania. Participants were not concurrently enrolled in another weekly meditation class.
View Article and Find Full Text PDFFocusing on microvascular function in heart failure with preserved ejection fraction.
Heart Fail Rev
January 2025
Department of Cardiology, Cardiology I, University Medical Center Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
Heart failure is a prevalent global health issue. Heart failure with preserved ejection fraction (HFpEF), which already represents half of all heart cases worldwide, is projected to further increase, driven by aging populations and rising cardiovascular risk factors. Effective therapies for HFpEF remain limited, particularly due to its pathophysiological heterogeneity and incomplete understanding of underlying pathomechanisms and implications.
View Article and Find Full Text PDFEnhancing Psychophysiological Well-Being Through Nature-Based Soundscapes: An Examination of Heart Rate Variability in a Cross-Over Study.
Psychophysiology
January 2025
Active Life Lab, South-Eastern Finland University of Applied Sciences, Mikkeli, Finland.
Stress and psychological disorders are substantial public health concerns, necessitating innovative therapeutic strategies. This study investigated the psychophysiological benefits of nature-based soundscapes, drawing on the biophilia hypothesis. Using a randomized, acute cross-over design, 53 healthy participants experienced either a nature-based or a reference soundscape for 10 min, with a 2-min washout period.
View Article and Find Full Text PDFTranscription introduces torsional stress in the DNA fiber causing it to transition from a relaxed to a supercoiled state that can propagate across several kilobases and modulate the binding and activity of DNA-associated proteins. As a result, transcription at one locus has the potential to impact nearby transcription events. In this study, we asked how DNA supercoiling affects histone modifications and transcription of neighboring genes in the multicellular eukaryote .
View Article and Find Full Text PDFFunctional resting state connectivity is differentially associated with IL-6 and TNF-α in depression and in healthy controls.
Sci Rep
January 2025
Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, J5, 68159, Mannheim, Germany.
Inflammatory processes have been implicated in the pathophysiology of depression. In human studies, inflammation has been shown to act as a critical disease modifier, promoting susceptibility to depression and modulating specific endophenotypes of depression. However, there is scant documentation of how inflammatory processes are associated with neural activity in patients with depression.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!