307 research outputs found

    Boundary effects in finite size plasmonic crystals: Focusing and routing of plasmonic beams for optical communications

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    Plasmonic crystals, which consist of periodic arrangements of surface features at a metal-dielectric interface, allow the manipulation of optical information in the form of surface plasmon polaritons. Here we investigate the excitation and propagation of plasmonic beams in and around finite size plasmonic crystals at telecom wavelengths, highlighting the effects of the crystal boundary shape and illumination conditions. Significant differences in broad plasmonic beam generation by crystals of different shapes are demonstrated, while for narrow beams, the propagation onto the smooth metal film is less sensitive to the crystal boundary shape. We show that by controlling the boundary shape, the size and the excitation beam parameters, directional control of propagating plasmonic modes and associated beam parameters such as angular beam splitting, focusing power and beam width can be efficiently achieved. This provides a promising route for robust and alignment-independent integration of plasmonic crystals with optical communication components

    Mediterranean diet and its components in relation to all-cause mortality: meta-analysis

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    The beneficial association of the Mediterranean diet (MedDiet) with longevity has been consistently demonstrated, but the associations of MedDiet components have not been accordingly evaluated. We performed an updated meta-analysis of prospective cohort studies published up to 31 December 2017, to quantify the association of adherence to MedDiet, expressed as an index/score (MDS) and of its components with all-cause mortality. We estimated summary relative risks (SRR) and 95 % CI using random effects models. On the basis of thirty studies (225 600 deaths), SRR for the study-specific highest/lowest and per 1sd MDS increment were 0\ub779 (95 % CI 0\ub777, 0\ub781, \u399 2=42 %, P-heterogeneity 0\ub702) and 0\ub792 (95 % CI 0\ub790, 0\ub794, \u399 2 56 %, P-heterogeneity <0\ub701), respectively. Inversely, statistically significant associations were evident in stratified analyses by country, MDS range and publication year, with some evidence for heterogeneity across countries overall (P-heterogeneity 0\ub7011), as well as across European countries (P=0\ub7018). Regarding MDS components, relatively stronger and statistically significant inverse associations were highlighted for moderate/none-excessive alcohol consumption (0\ub786, 95 % CI 0\ub777, 0\ub797) and for above/below-the-median consumptions of fruit (0\ub788, 95 % CI 0\ub783, 0\ub794) and vegetables (0\ub794, 95 % CI 0\ub789, 0\ub798), whereas a positive association was apparent for above/below-the-median intake of meat (1\ub707, 95 % CI 1\ub701, 1\ub713). Our meta-analyses confirm the inverse association of MedDiet with mortality and highlight the dietary components that influence mostly this association. Our results are important for better understanding the role of MedDiet in health and proposing dietary changes to effectively increase adherence to this healthy dietary pattern

    The Antioxidant Potential of the Mediterranean Diet in Patients at High Cardiovascular Risk: An In-Depth Review of the PREDIMED

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    Cardiovascular disease (CVD) is the leading global cause of death. Diet is known to be important in the prevention of CVD. The PREDIMED trial tested a relatively low-fat diet versus a high-fat Mediterranean diet (MedDiet) for the primary prevention of CVD. The resulting reduction of the CV composite outcome resulted in a paradigm shift in CV nutrition. Though many dietary factors likely contributed to this effect, this review focuses on the influence of the MedDiet on endogenous antioxidant systems and the effect of dietary polyphenols. Subgroup analysis of the PREDIMED trial revealed increased endogenous antioxidant and decreased pro-oxidant activity in the MedDiet groups. Moreover, higher polyphenol intake was associated with lower incidence of the primary outcome, overall mortality, blood pressure, inflammatory biomarkers, onset of new-onset type 2 diabetes mellitus (T2DM), and obesity. This suggests that polyphenols likely contributed to the lower incidence of the primary event in the MedDiet groups. In this article, we summarize the potential benefits of polyphenols found in the MedDiet, specifically the PREDIMED cohort. We also discuss the need for further research to confirm and expand the findings of the PREDIMED in a non-Mediterranean population and to determine the exact mechanisms of action of polyphenols

    Burden of hip fracture using disability-adjusted life-years: a pooled analysis of prospective cohorts in the CHANCES consortium

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    Background No studies have estimated disability-adjusted life-years (DALYs) lost due to hip fractures using real-life follow-up cohort data. We aimed to quantify the burden of disease due to incident hip fracture using DALYs in prospective cohorts in the CHANCES consortium, and to calculate population attributable fractions based on DALYs for specific risk factors. Methods We used data from six cohorts of participants aged 50 years or older at recruitment to calculate DALYs. We applied disability weights proposed by the National Osteoporosis Foundation and did a series of sensitivity analyses to examine the robustness of DALY estimates. We calculated population attributable fractions for smoking, body-mass index (BMI), physical activity, alcohol intake, type 2 diabetes and parity, use of hormone replacement therapy, and oral contraceptives in women. We calculated summary risk estimates across cohorts with pooled analysis and randomeffects meta-analysis methods. Findings 223 880 men and women were followed up for a mean of 13 years (SD 6). 7724 (3·5%) participants developed an incident hip fracture, of whom 413 (5·3%) died as a result. 5964 DALYs (27 per 1000 individuals) were lost due to hip fractures, 1230 (20·6%) of which were in the group aged 75–79 years. 4150 (69·6%) DALYs were attributed to disability. Current smoking was the risk factor responsible for the greatest hip fracture burden (7·5%, 95% CI 5·2–9·7) followed by physical inactivity (5·5%, 2·1–8·5), history of diabetes (2·8%, 2·1–4·0), and low to average BMI (2·0%, 1·4–2·7), whereas low alcohol consumption (0·01–2·5 g per day) and high BMI had a protective effect. Interpretation Hip fracture can lead to a substantial loss of healthy life-years in elderly people. National public health policies should be strengthened to reduce hip fracture incidence and mortality. Primary prevention measures should be strengthened to prevent falls, and reduce smoking and a sedentary lifestyle

    Insulin-like growth factor I and risk of epithelial invasive ovarian cancer by tumour characteristics: results from the EPIC cohort

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    Background: Prospective studies on insulin-like growth factor I (IGF-I) and epithelial ovarian cancer (EOC) risk are inconclusive. Data suggest risk associations vary by tumour characteristics. Methods: We conducted a nested case-control study in the European Prospective Investigation into Cancer and Nutrition (EPIC) to evaluate IGF-I concentrations and EOC risk by tumour characteristics (n=565 cases). Multivariable conditional logistic regression models were used to estimate associations. Results: We observed no association between IGF-I and EOC overall or by tumour characteristics. Conclusions: In the largest prospective study to date was no association between IGF-I and EOC risk. Pre-diagnostic serum IGF-I concentrations may not influence EOC risk

    Association between vitamin B12 intake and EURRECA’s prioritized biomarkers of vitamin B12 in young populations: a systematic review

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    Objective To review evidence on the associations between vitamin B12 intake and its biomarkers, vitamin B12 intake and its functional health outcomes, and vitamin B12 biomarkers and functional health outcomes. Design A systematic review was conducted by searching electronic databases, until January 2012, using a standardized strategy developed in the EURRECA network. Relevant articles were screened and sorted based on title and abstract, then based on full text, and finally included if they met inclusion criteria. A total of sixteen articles were included in the review. Setting Articles covered four continents: America (n 4), Europe (n 8), Africa (n 1) and Asia (n 3). Subjects Population groups included healthy infants, children and adolescents, and pregnant and lactating women. Results From the total number of 5815 papers retrieved from the initial search, only sixteen were eligible according to the inclusion criteria: five for infants, five for children and adolescents, and six for pregnant and lactating women. Conclusions Only one main conclusion could be extracted from this scarce number of references: a positive association between vitamin B12 intake and serum vitamin B12 in the infant group. Other associations were not reported in the eligible papers or the results were not provided in a consistent manner. The low number of papers that could be included in our systematic review is probably due to the attention that is currently given to research on vitamin B12 in elderly people. Our observations in the current systematic review justify the idea of performing well-designed studies on vitamin B12 in young populations

    Fruit and vegetable intake and risk of cancer in the Swedish women’s lifestyle and health cohort

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    Objective To investigate whether intake of fruits and vegetables is associated with overall cancer incidence in a large prospective cohort of women in Sweden characterised by young age at enrolment (30–49 years) and relatively low intake of fruits and vegetables. Methods We followed prospectively 49,261 women, who completed a food frequency questionnaire in 1991–1992. A total of 2,347 incident invasive cancer cases were identified until December 2006. The occurrence of cancer was analysed by fitting Poisson regression models, estimating incidence rate ratios (RR) and 95% confidence intervals (CI). Results The median intake of fruits and vegetables was 204 g/day (10th; 90th percentile: 37; 564 g/day). Intake of fruits and vegetables was not statistically significantly associated with overall cancer incidence. When we compared women in the highest quintile of fruit and vegetable intake to women in the lowest quintile, the RR for overall cancer was 1.01 (95% CI: 0.88–1.16). Similar results were obtained when investigating the effect of intake of fruits and vegetables separately and when we stratified women by age at follow-up. Conclusion Fruit and vegetable intake was not associated with risk of total cancer in this prospective cohort of women in Sweden

    Epidemiology of fractures in Armenia: development of a country-specific FRAX model and comparison to its surrogate

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    Summary: Fracture probabilities derived from the surrogate FRAX model for Armenia were compared to those from the model based on regional estimates of the incidence of hip fracture. Disparities between the surrogate and authentic FRAX models indicate the importance of developing country-specific FRAX models. Despite large differences between models, differences in the rank order of fracture probabilities were minimal. Objective: Armenia has relied on a surrogate FRAX model based on the fracture epidemiology of Romania. This paper describes the epidemiology of fragility fractures in Armenia used to create an Armenia-specific FRAX model with an aim of comparing this new model with the surrogate model. Methods: We carried out a population-based study in two regions of Armenia (Ararat and Vayots Dzor representing approximately 11% of the country’s population). We aimed to identify all low-energy fractures: retrospectively from hospital registers in 2011–2012 and prospectively in 2013 with the inclusion of primary care sources. Results: The differences in incidence between the surveys with and without data from primary care suggested that 44% of patients sustaining a hip fracture did not receive specialized medical care. A similar proportion of forearm and humeral fractures did not come to hospital attention (48 and 49%, respectively). Only 57.7% of patients sustaining a hip fracture were hospitalized. In 2013, hip fracture incidence at the age of 50 years or more was 201/100,000 for women and 136/100,000 for men, and age- and sex-specific rates were incorporated into the new “authentic” FRAX model for Armenia. Compared to the surrogate model, the authentic model gave lower 10-year fracture probabilities in men and women aged less than 70 years but substantially higher above this age. Notwithstanding, there were very close correlations in fracture probabilities between the surrogate and authentic models ( >  0.99) so that the revisions had little impact on the rank order of risk. Conclusion: A substantial proportion of major osteoporotic fractures in Armenia do not come to hospital attention. The disparities between surrogate and authentic FRAX models indicate the importance of developing country-specific FRAX models. Despite large differences between models, differences in the rank order of fracture probabilities were minimal

    Reproductive and hormone-related risk factors for epithelial ovarian cancer by histologic pathways, invasiveness and histologic subtypes: results from the EPIC cohort

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    Whether risk factors for epithelial ovarian cancer (EOC) differ by subtype (i.e., dualistic pathway of carcinogenesis, histologic subtype) is not well understood; however, data to date suggest risk factor differences. We examined associations between reproductive and hormone-related risk factors for EOC by subtype in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Among 334,126 women with data on reproductive and hormone-related risk factors (follow-up: 1992–2010), 1,245 incident cases of EOC with known histology and invasiveness were identified. Data on tumor histology, grade, and invasiveness, were available from cancer registries and pathology record review. We observed significant heterogeneity by the dualistic model (i.e., type I [low grade serous or endometrioid, mucinous, clear cell, malignant Brenner] vs. type II [high grade serous or endometrioid]) for full-term pregnancy (phet = 0.02). Full-term pregnancy was more strongly inversely associated with type I than type II tumors (ever vs. never: type I: relative risk (RR) 0.47 [95% confidence interval (CI): 0.33–0.69]; type II, RR: 0.81 [0.61–1.06]). We observed no significant differences in risk in analyses by major histologic subtypes of invasive EOC (serous, mucinous, endometrioid, clear cell). None of the investigated factors were associated with borderline tumors. Established protective factors, including duration of oral contraceptive use and full term pregnancy, were consistently inversely associated with risk across histologic subtypes (e.g., ever full-term pregnancy: serous, RR: 0.73 [0.58–0.92]; mucinous, RR: 0.53 [0.30–0.95]; endometrioid, RR: 0.65 [0.40–1.06]; clear cell, RR: 0.34 [0.18–0.64]; phet = 0.16). These results suggest limited heterogeneity between reproductive and hormone-related risk factors and EOC subtypes
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