Učinak Butadin-akrilnog umreživača na udarnu čvrstoću poli(metilmetakrilata)

A cross-linking agent, ethylene glycol dimethacrylate, which is added to poly (methyl methacrylate) (VMMA) denture base resins to improve crazing resistance, has little effect on the mechanical properties o f the resultant denture base. A poly functional cross-linking agent, butadiene acrylate (BDA), has been considered to have a greater cross-linking efficiency and thus altering the mechanical properties. The purpose o f this study was to investigate the effect o f BDA on the impact strength o f a PMMA specimens containing 0%, 1%, 4% and 12% BDA o f monomer volume which had been produced by a conventional dental dough-moulded technique as determined. Mean impact strengths were 1.789 KJ/m2 (SD 0.254), 1.720 KJ/m2 (SD 0.273); 1.715 KJ/m2 (SD 0.280) and 1.838 KJ/m2 (SD 0.244), respectively. These differences were not significant (p >0.05) as tested by the analysis o f variance. It was concluded that the cross-linking agent BDA did not affect the impact strength of the PMMA resin specimens.U svrhu povećanja otpornosti poli(metilmetakrilatnih) proteznih smola na lomove i stvaranje napuklina, monomer-kapljevini se tvornički dodaje tvar za umrežavanje, najčešće etilen-glikol-dimetakrilat (EGDMA), koji se u tome smislu nije pokazao učinkovitim. Ovo istraživanje je provedeno s pretpostavkom da bi polifunkcionalna tvar za umrežavanje, kao što je to butadin - akrilat (BDA), mogla imati veći učinak na umrežavanje i poboljšanje mehaničkih svojstava poli(metilmetakrilatnih) smola. Ispitivana je udarna čvrstoća Zwick-postupkom poli(metilmetakrilatnih) pripravaka, podijeljenih u četiri skupine s obzirom na količinu tvari za umreživanje (0%, 1%, 4% i 12%), te dobivenih uobičajenom kivetnom tehnikom oplopolimerizirajućeg postupka. Vrijednosti za udarnu čvrstoću pripravaka po skupinama iznosile su: 0% BDA - 1,789 KJ/m2 (SD 0,254); 1% BDA - 1,720 KJ/m2 (SD 0,273); 4% BDA - 1,715 KJ/m2 (SD 0,280) i 12% BDA - 1,838 KJ/m2 (SD 0,244), a razlike među skupinama nisu se pokazale statistički značajnim (p > 0,05). Zaključeno je da istraživana tvar za umrežavanje (BDA) nije doprinijela poboljšanju udarne čvrstoće poli(metilmetakrilatnih) pripravaka

Surface Modification of an Experimental Silicone Rubber Maxillofacial Material to Improve Wettability

OBJECTIVES: Good wettability of maxillofacial prosthetic materials is important so hat a lubricating layer is formed with supporting tissues thus reducing patient discomfort. The purpose of the study was to surface modify an experimental silicone rubber material in order to improve wettability. METHODS : Samples of experimental silicone rubber were surface modified by first argon plasma treatment followed by chemisorption of ethyleneoxy functional silanes. These were compared with the same silicone rubber which had ethyleneoxy functional surfactants incorporated into the polymer matrix. In all cases contact angles, tear strength and water uptake were measured. RESULTS: Surface modified materials had comparable contact angles to surfactant modified silicone rubber, all being significantly lower than the unmodified material. Surface modified materials however had a significantly higher tear strength and lower water uptake in comparison to surfactant modified materials. CONCLUSION: Argon plasma treatment followed by chemisorption of ethyleneoxy functional silanes proved an effective way of improving the wettability of an experimental silicone rubber maxillofacial prosthetic material without altering bulk properties

Gender, education, and cohort differences in healthy working life expectancy at age 50 years in Australia: a longitudinal analysis

Background: We aimed to estimate healthy working life expectancy (HWLE) at age 50 years by gender, cohort, and level of education in Australia. Methods: We analysed data from two nationally representative cohorts in the Household Income and Labour Dynamics in Australia survey. Each cohort was followed up annually from 2001 to 2010 and from 2011 to 2020. Poor health was defined by a self-reported, limiting, long-term health condition. Work was defined by current employment status. HWLEs were estimated with Interpolated Markov Chain multi-state modelling. Findings: We included data from 4951 participants in the cohort from 2001 to 2010 (2605 [53%] women and 2346 [47%] men; age range 50–100 years) and 6589 participants in the cohort from 2011 to 2020 (3518 [53%] women and 3071 [47%] men; age range 50–100 years). Baseline characteristics were similar between groups. Working life expectancy increased over time for all groups, regardless of gender or educational attainment. However, health expectancies only increased for men and people of either gender with higher education. Years working in good health at age 50 years for men were 9·9 years in 2001 (95% CI 9·3–10·4) and 10·8 years (10·4–11·3) in 2011. The corresponding HWLEs for women were 7·9 years (7·3–8·5) and 9·0 years (8·5–9·6). For people with low education level, HWLE was 7·9 years (7·3–8·5) in 2001 and 8·4 years (7·9–8·9) in 2011, and for those with high education level, HWLE rose from 9·6 years in 2001 (9·1–10·1) to 10·5 years in 2011 (10·2–10·9). Across all groups, there were at least 2·5 years working in poor health and 6·7 years not working in good health. Interpretation: Increases in length of working life have not been accompanied by similar gains in healthy life expectancy for women or people of any gender with low education, and it is not unusual for workers older than 50 years to work with long-term health limitations. Strategies to achieve longer working lives should address life-course inequalities in health and encourage businesses and organisations to recruit, train, and retain mature-age workers. Funding: Australian Research Council

Resistance factors to rapid response in natural disaster scenarios

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Characterizing human vestibular sensory epithelia for experimental studies: new hair bundles on old tissue and implications for therapeutic interventions in ageing.

Balance disequilibrium is a significant contributor to falls in the elderly. The most common cause of balance dysfunction is loss of sensory cells from the vestibular sensory epithelia of the inner ear. However, inaccessibility of inner ear tissue in humans severely restricts possibilities for experimental manipulation to develop therapies to ameliorate this loss. We provide a structural and functional analysis of human vestibular sensory epithelia harvested at trans-labyrinthine surgery. We demonstrate the viability of the tissue and labeling with specific markers of hair cell function and of ion homeostasis in the epithelium. Samples obtained from the oldest patients revealed a significant loss of hair cells across the tissue surface, but we found immature hair bundles present in epithelia harvested from patients >60 years of age. These results suggest that the environment of the human vestibular sensory epithelium could be responsive to stimulation of developmental pathways to enhance hair cell regeneration, as has been demonstrated successfully in the vestibular organs of adult mice

Demographic, health, physical activity, and workplace factors are associated with lower healthy working life expectancy and life expectancy at age 50

\ua9 The Author(s) 2024.Although retirement ages are rising in the United Kingdom and other countries, the average number of years people in England can expect to spend both healthy and work from age 50 (Healthy Working Life Expectancy; HWLE) is less than the number of years to the State Pension age. This study aimed to estimate HWLE with the presence and absence of selected health, socio-demographic, physical activity, and workplace factors relevant to stakeholders focusing on improving work participation. Data from 11,540 adults in the English Longitudinal Study of Ageing were analysed using a continuous time 3-state multi-state model. Age-adjusted hazard rate ratios (aHRR) were estimated for transitions between health and work states associated with individual and combinations of health, socio-demographic, and workplace factors. HWLE from age 50 was 3.3 years fewer on average for people with pain interference (6.54 years with 95% confidence interval [6.07, 7.01]) compared to those without (9.79 [9.50, 10.08]). Osteoarthritis and mental health problems were associated with 2.2 and 2.9 fewer healthy working years respectively (HWLE for people without osteoarthritis: 9.50 years [9.22, 9.79]; HWLE with osteoarthritis: 7.29 years [6.20, 8.39]; HWLE without mental health problems: 9.76 years [9.48, 10.05]; HWLE with mental health problems: 6.87 years [1.58, 12.15]). Obesity and physical inactivity were associated with 0.9 and 2.0 fewer healthy working years respectively (HWLE without obesity: 9.31 years [9.01, 9.62]; HWLE with obesity: 8.44 years [8.02, 8.86]; HWLE without physical inactivity: 9.62 years [9.32, 9.91]; HWLE with physical inactivity: 7.67 years [7.23, 8.12]). Workers without autonomy at work or with inadequate support at work were expected to lose 1.8 and 1.7 years respectively in work with good health from age 50 (HWLE for workers with autonomy: 9.50 years [9.20, 9.79]; HWLE for workers lacking autonomy: 7.67 years [7.22, 8.12]; HWLE for workers with support: 9.52 years [9.22, 9.82]; HWLE for workers with inadequate support: 7.86 years [7.22, 8.12]). This study identified demographic, health, physical activity, and workplace factors associated with lower HWLE and life expectancy at age 50. Identifying the extent of the impact on healthy working life highlights these factors as targets and the potential to mitigate against premature work exit is encouraging to policy-makers seeking to extend working life as well as people with musculoskeletal and mental health conditions and their employers. The HWLE gaps suggest that interventions are needed to promote the health, wellbeing and work outcomes of subpopulations with long-term health conditions

Is late-life dependency increasing or not? A comparison of the Cognitive Function and Ageing Studies (CFAS)

Background: Little is known about how the proportions of dependency states have changed between generational cohorts of older people. We aimed to estimate years lived in different dependency states at age 65 years in 1991 and 2011, and new projections of future demand for care. Methods: In this population-based study, we compared two Cognitive Function and Ageing Studies (CFAS I and CFAS II) of older people (aged ≥65 years) who were permanently registered with a general practice in three defined geographical areas (Cambridgeshire, Newcastle, and Nottingham; UK). These studies were done two decades apart (1991 and 2011). General practices provided lists of individuals to be contacted and were asked to exclude those who had died or might die over the next month. Baseline interviews were done in the community and care homes. Participants were stratified by age, and interviews occurred only after written informed consent was obtained. Information collected included basic sociodemographics, cognitive status, urinary incontinence, and self-reported ability to do activities of daily living. CFAS I was assigned as the 1991 cohort and CFAS II as the 2011 cohort, and both studies provided prevalence estimates of dependency in four states: high dependency (24-h care), medium dependency (daily care), low dependency (less than daily), and independent. Years in each dependency state were calculated by Sullivan's method. To project future demands for social care, the proportions in each dependency state (by age group and sex) were applied to the 2014 England population projections. Findings: Between 1991 and 2011, there were significant increases in years lived from age 65 years with low dependency (1·7 years [95% CI 1·0-2·4] for men and 2·4 years [1·8-3·1] for women) and increases with high dependency (0·9 years [0·2-1·7] for men and 1·3 years [0·5-2·1] for women). The majority of men's extra years of life were spent independent (36·3%) or with low dependency (36·3%) whereas for women the majority were spent with low dependency (58·0%), and only 4·8% were independent. There were substantial reductions in the proportions with medium and high dependency who lived in care homes, although, if these dependency and care home proportions remain constant in the future, further population ageing will require an extra 71 215 care home places by 2025. Interpretation: On average older men now spend 2·4 years and women 3·0 years with substantial care needs, and most will live in the community. These findings have considerable implications for families of older people who provide the majority of unpaid care, but the findings also provide valuable new information for governments and care providers planning the resources and funding required for the care of their future ageing populations. Funding: Medical Research Council (G9901400) and (G06010220), with support from the National Institute for Health Research Comprehensive Local research networks in West Anglia and Trent, UK, and Neurodegenerative Disease Research Network in Newcastle, UK