973 research outputs found
Bioactive Glass/Gelatin Hybrid Biomaterials for Bone Tissue Engineering
Hybrid biomaterials combining bioactive glasses (BAG) and natural polymers such as gelatin, are potential alternatives for bone tissue engineering applications. The inorganic and organic phases in a hybrid interact at a molecular scale and are connected via covalent bonds due to coupling agents such as 3-glycidoxypropyl trimethoxysilane (GPTMS). Owing to the strong covalent bonding between phases it is possible to create materials with controllable degradation (both aqueous and enzymatic), and bioactivity. Furthermore, the rheological properties of the materials can be adjusted to increase the mechanical properties and/or allow shaping of the hybrid into a specific shape.
In this study, hybrids with either silicate glass S53P4, or Mg and Sr-doped borosilicate glass B12.5 –Mg 5- Sr 10 (“mix”) combined to organic gelatin phase were synthesized with different weight ratios between phases: 30/70 (glass/gelatin), 15/85, 5/95 and 1/99. The aim of this study was to assess in vitro properties of these hybrid biomaterials. The bioactivity and degradation behaviour of the hybrids were investigated in Simulated Body Fluid (SBF) and in enzymatic collagenase solution. SBF dissolution experiment was carried out for two weeks, and enzymatic degradation experiment for six hours. At every time point, samples’ mass loss and ion release behaviour were studied, and SBF samples’ pH changes were measured.
For further characterization of the hybrids, rheological measurements were performed to understand the gelation behaviour of the hybrids, and thermogravimetric analysis (TGA) to assess the inorganic/organic phase ratio.
In addition, the biocompatibility of BAG/gelatin hybrid materials were evaluated by culturing human-derived mesenchymal stem cells (hBMSCs) in contact with hybrid samples and with hybrid dissolution product extracts. Furthermore, the ion concentrations in cell culturing medium upon culturing were also measured.
Based on the results, the hybrids were stable in aqueous solutions, and exhibited controlled ion release suggesting hydroxyapatite (HA) layer precipitation. The hybrids were also more resistant to enzymatic degradation than the gelatin alone. However, based on the Live/Dead results all hybrid compositions showed an inhibitory effect in hBMSC proliferation after 72 hours of culturing, possibly due to too high reactivity or release of unreacted compounds, such as the coupling agent GPTMS. Further cell studies and optimization of the hybrid biomaterial are needed to confirm the suitability of hybrids as a biocompatible bone tissue engineering scaffold materia
Sleep improvement by internet-based cognitive behavioural therapy might help prevent mental health disorders
Non peer reviewe
Lost in Autonomy – Temporal Structures and Their Implications for Employees’ Autonomy and Well-Being among Knowledge Workers
Conceptual models based on the importance of work autonomy for employees’ health represent important cornerstones in the occupational well-being and work stress literature. The objectives of this study were to 1) explore and understand the temporal conditions framing work among autonomous knowledge professionals, 2) describe how autonomy is experienced in knowledge work jobs, and 3) analyze the implications of current autonomy for well-being in knowledge work. The interview study consisted of 21 women and 13 men who worked in knowledge-intensive jobs in Finland. Analysis of the material shows that knowledge work is structured by different levels of transverse temporal structures: individual and social structures, and organizational and macrolevel structures. This creates a paradoxical nature of autonomy among knowledge workers, characterized by high task autonomy and intense socio-temporal interdependence. One can have strong autonomy and be tied at the same time. Unsynchronized time structures can lead to fragmented work, overwhelming work burden, and higher risk of mental health symptoms. It would therefore be advisable to establish collective temporal structures in organizations that create manageability and predictability. We conclude that models of occupational well-being and work stress should pay more attention to the social structure and temporal interdependencies that characterize knowledge work.Peer reviewe
Non-alcoholic fatty liver disease and risk of type 2 diabetes
Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of liver disease from simple steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is commonly associated with features of the metabolic/insulin resistance syndrome ('Metabolic/Obese NAFLD') and may therefore predict type 2 diabetes (T2DM). For this review, we searched for prospective studies examining whether NAFLD predicts T2DM, and if so, whether this occurs independently of factors such as age and obesity. These studies included NAFLD diagnosed by ultrasonography (n = 6) or liver enzymes (n = 14). All ultrasonography studies found NAFLD to predict the risk of T2DM independently of age, and in 4 out of 6 studies NAFLD was also a predictor independently of BMI. NAFLD was a predictor of T2DM in all 14 studies where NAFLD was diagnosed by liver enzymes. In 12 of these studies, ALT or AST or GGT were significant predictors of T2DM risk, independently of age and BMI. NAFLD, however, is heterogeneous and may also be caused by common genetic variants. The I148M variant in PNPLA3 and the E167K variant in TM6SF2 are both associated with increased liver fat content, but not features of the metabolic/insulin resistance syndrome. These genetic forms of NAFLD predict NASH and cirrhosis but not T2DM. Taken together these data imply that 'Metabolic/Obese NAFLD' predicts T2DM independently of age and obesity and support the role of hepatic insulin resistance in the pathogenesis of this disease. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe
Virallisten lajikekokeiden tulosyhdistelmiä 1979
On olemassa kaksi erilaista Kasvinviljelylaitoksen tiedotetta n:o 17vokKirjasto Aj-
Rikkakasvien torjunta-aineiden ja kasvunsääteiden koetulokset 1976 Peltoviljely
vokKirjasto Aj-
Body mass index and the risk of disability retirement : a systematic review and meta-analysis
The aim of this study was to determine the associations of body mass index (BMI) with all-cause and cause-specific disability retirement. Literature searches were conducted in PubMed, Embase and Web of Science from their inception to May 2019. A total of 27 (25 prospective cohort and 2 nested case-control) studies consisting of 2 199 632 individuals qualified for a meta-analysis. Two reviewers independently assessed the methodological quality of the included studies. We used a random effects meta-analysis, assessed heterogeneity and publication bias, and performed sensitivity analyses. There were a large number of participants and the majority of studies were rated at low or moderate risk of bias. There was a J-shaped relationship between BMI and disability retirement. Underweight (hazard ratio (HR)/risk ratio (RR)=1.20, 95% CI 1.02 to 1.41), overweight (HR/RR=1.13, 95% CI 1.07 to 1.19) and obese individuals (HR/RR=1.52, 95% CI 1.36 to 1.71) were more commonly granted all-cause disability retirement than normal-weight individuals. Moreover, overweight increased the risk of disability retirement due to musculoskeletal disorders (HR/RR=1.26, 95% CI 1.15 to 1.39) and cardiovascular diseases (HR=1.73, 95% CI 1.24 to 2.41), and obesity increased the risk of disability retirement due to musculoskeletal disorders (HR/RR=1.66, 95% CI 1.42 to 1.94), mental disorders (HR=1.29, 95% CI 1.04 to 1.61) and cardiovascular diseases (HR=2.80, 95% CI 1.85 to 4.24). The association between excess body mass and all-cause disability retirement did not differ between men and women and was independent of selection bias, performance bias, confounding and adjustment for publication bias. Obesity markedly increases the risk of disability retirement due to musculoskeletal disorders, cardiovascular diseases and mental disorders. Since the prevalence of obesity is increasing globally, disease burden associated with excess body mass and disability retirement consequently are projected to increase. Reviewregistrationnumber: CRD42018103110.Peer reviewe
- …