| 331. |
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| 332. |
- Enqvist, Evelina, et al.
(författare)
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The effect of ball milling time and rotational speed on ultra high molecular weight polyethylene reinforced with multiwalled carbon nanotubes
- 2016
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Ingår i: Polymer Composites. - : Wiley. - 0272-8397 .- 1548-0569. ; 37:4, s. 1128-1136
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Tidskriftsartikel (refereegranskat)abstract
- Ultra high molecular weight polyethylene (UHMWPE) composites reinforced with multiwalled carbon nanotubes (MWCNT) were produced using planetary ball milling. The aim was to develop a more wear resistant composite with increased mechanical properties to be used in stress bearing joints. The manufacturing technique, using ball-milling to incorporate MWCNT into UHMWPE matrix was investigated. The effect of manufacturing parameters such as effect of ball milling time and rotational speed on final composite was analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), particle size distribution and contact angle measurements. Ball milling as mixing technique for UHMWPE based composites is not a new approach but yet, the effect of time, rotational speed, loading of milling jar and type of ball mill has not been reported properly for UHMWPE. 0.5 and 1 wt% UHMWPE/MWCNTs were manufactured at different rotational speed and mixing time. The results indicate that rotational speed rather than mixing time is important for dispersing MWCNTs
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| 333. |
- Fawsitt, C. G., et al.
(författare)
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Choice of Prosthetic Implant Combinations in Total Hip Replacement: Cost-Effectiveness Analysis Using UK and Swedish Hip Joint Registries Data
- 2019
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Ingår i: Value in Health. - : Elsevier BV. - 1098-3015. ; 22:3, s. 303-312
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prosthetic implants used in total hip replacements (THR) have a range of bearing surface combinations (metal-onpolyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, and metal-on-metal), head sizes (small [<36 mm in diameter] and large [>= 36 mm in diameter]), and fixation techniques (cemented, uncemented, hybrid, and reverse hybrid). These can influence prosthesis survival, patients' quality of life, and healthcare costs. Objectives: To compare the lifetime cost-effectiveness of implants for patients of different age and sex profiles. Methods: We developed a Markov model to compare the cost-effectiveness of various implants against small-head cemented metal-on-polyethylene implants. The probability that patients required 1 or more revision surgeries was estimated from analyses of more than 1 million patients in the UK and Swedish hip joint registries, for men and women younger than 55, 55 to 64, 65 to 74, 75 to 84, and 85 years and older. Implant and healthcare costs were estimated from local procurement prices, national tariffs, and the literature. Quality-adjusted life-years were calculated using published utility estimates for patients undergoing THR in the United Kingdom. Results: Small-head cemented metal-on-polyethylene implants were the most cost-effective for men and women older than 65 years. These findings were robust to sensitivity analyses. Small-head cemented ceramic-on-polyethylene implants were most cost-effective in men and women younger than 65 years, but these results were more uncertain. Conclusions: The older the patient group, the more likely that the cheapest implants, small-head cemented metal-on-polyethylene implants, were cost-effective. We found no evidence that uncemented, hybrid, or reverse hybrid implants were the most cost-effective option for any patient group. Our findings can influence clinical practice and procurement decisions for healthcare payers worldwide.
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| 334. |
- Ferreira da Silva, Eduardo, et al.
(författare)
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Heavy metal pollution downstream the abandoned Coval da Mó mine (Portugal) and associated effects on epilithic diatom communities
- 2009
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 407:21, s. 5620-5636
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Tidskriftsartikel (refereegranskat)abstract
- This study examined trace-element concentrations in 39 sediment samples collected in the vicinity of the abandoned Coval da Mó mine, and evaluated the anthropogenic contaminant effects and other environmental variables in the taxonomic composition, structure and morphological changes of benthic diatom communities.The results show the existence of extremely high contamination in Pb, Zn and Cd (the mean values exceed the background values 376, 96 and 19 times, respectively) on the first 2.5 km in the water flow direction. Also Co, Cu, Mn and Ni are present in high concentrations. Dilution by relatively uncontaminated sediment reduces metal concentrations downstream, but Zn concentrations increase downstream Fílvida stream, as a result of several factors such as sewage and agriculture.To evaluate the biological effects caused by Pb, Cd and Zn, three sites were selected. In the stressed environment, near the mining area (C232), diatoms were extremely rare, however there was a slight recovery at site C79 located 2 km downstream. Fragilaria capucina var. rumpens, Fragilaria cf. crotonensis and Achnanthidium minutissimum showed abnormal valves which may be related to high levels of metals.Six km downstream, in Fílvida stream (C85), an increase in species richness and diversity was registered while the relative percentage of valve teratologies was lower. In the absence of OM, nutrients and low pH the diatom community patterns must be attributed to the metal concentration at some sites. Considering that community diversity can be affected by abiotic and biotic variables and valve deformations are caused by a small number of variables, basically metals, and acid conditions, we consider the presence of teratologies as an indication of the presence of metals.
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| 335. |
- Ferreira, Mafalda S., et al.
(författare)
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The transcriptional landscape of seasonal coat colour moult in the snowshoe hare
- 2017
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 26:16, s. 4173-4185
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Tidskriftsartikel (refereegranskat)abstract
- Seasonal coat colour change is an important adaptation to seasonally changing environments but the evolution of this and other circannual traits remains poorly understood. In this study, we use gene expression to understand seasonal coat colour moulting in wild snowshoe hares (Lepus americanus). We used hair colour to follow the progression of the moult, simultaneously sampling skin from three moulting stages in hares collected during the peak of the spring moult from white winter to brown summer pelage. Using RNA sequencing, we tested whether patterns of expression were consistent with predictions based on the established phases of the hair growth cycle. We found functionally consistent clustering across skin types, with 766 genes differentially expressed between moult stages. “White” pelage showed more differentially expressed genes that were upregulated relative to other skin types, involved in the transition between late telogen (quiescent stage) and the onset of anagen (proliferative stage). Skin samples from transitional “intermediate” and “brown” pelage were transcriptionally similar and resembled the regressive transition to catagen (regressive stage). We also detected differential expression of several key circadian clock and pigmentation genes, providing important means to dissect the bases of alternate seasonal colour morphs. Our results reveal that pelage colour is a useful biomarker for seasonal change but that there is a consistent lag between the main gene expression waves and change in visible coat colour. These experiments establish that developmental sampling from natural populations of nonmodel organisms can provide a crucial resource to dissect the genetic basis and evolution of complex seasonally changing traits.
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| 336. |
- Frago, Enric, et al.
(författare)
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Common pheromone use among host-associated populations of the browntail moth, euproctis chrysorrhoea, displaying different adult phenologies
- 2019
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Ingår i: Entomologia Generalis. - : Schweizerbart. - 0171-8177. ; 39:3-4, s. 295-306
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Tidskriftsartikel (refereegranskat)abstract
- The diversity of herbivorous insects may arise from colonization and subsequent specialization on different host plants. Such specialization requires changes in several insect traits, which may lead to host race formation if they reduce gene flow among populations that feed on different plants. Behavioural changes may play a relevant role in host race formation, for example if different races evolve distinct sexual communication signals or adult phenology. Previous research has revealed differences in larval phenology in different host-associated populations of the browntail moth, Euproctis chrysorrhoea (Lepidoptera: Erebidae). Here, sex pheromones among populations of this species are compared, and pheromone trapping data obtained is used in the field to build a phenological model that tests whether populations that feed on different plants differ in their adult flight period. The chemical and electrophysiological analyses revealed that two E. chrysorrhoea populations (on Prunus and on Arbutus unedo) use the same sex pheromone component for mate finding. Our trapping data, however, showed that males fly on average 25 days earlier in populations whose larvae feed on A. unedo compared to those whose larvae feed on Quercus species. Although the shifted phenology described here may underlie host-plant specialization in E. chrysorrhoea, and adults of this species are short-lived, the use of a common sexual pheromone and a large overlap in flight periods suggest that host race formation via allochronic isolation is unlikely in this moth.
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| 337. |
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| 338. |
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| 339. |
- Gaboardi, M, et al.
(författare)
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Goals and Principles of Providers Working with People Experiencing Homelessness: A Comparison Between Housing First and Traditional Staircase Services in Eight European Countries
- 2019
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Ingår i: International journal of environmental research and public health. - : MDPI AG. - 1660-4601. ; 16:9
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Tidskriftsartikel (refereegranskat)abstract
- The implementation and adaptation of the Housing First (HF) model represented profound changes the structure and delivery, goals, and principles of homeless services. These features of homeless services directly influence providers, their work performance and the clients’ outcomes. The present research, conducted in eight European countries, investigated how social providers working in HF or TS (Traditional Staircase) describe and conceptualize the goals and the principles of their services. Data were collected through 29 focus group discussions involving 121 providers. The results showed that HF and TS had similar and different goals for their clients in the following areas: support, social integration, satisfaction of needs, housing, and well-being. HF providers emphasized clients’ autonomy and ability to determine their personal goals, with housing being considered a start on the path of recovery, while TS were more focused on individual clients’ basic needs with respect to food, health and finding temporary accommodations. HF providers privileged the person-centered approach and housing as a right, while TS providers were more focused on helping everyone. Implications of the results are discussed as suggestions both for practice and for research.
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| 340. |
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