832 research outputs found

    Frontiers of light manipulation in natural, metallic, and dielectric nanostructures

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    AbstractThe ability to control light at the nanoscale is at the basis of contemporary photonics and plasmonics. In particular, properly engineered periodic nanostructures not only allow the inhibition of propagation of light at specific spectral ranges or its confinement in nanocavities or waveguides, but make also possible field enhancement effects in vibrational, Raman, infrared and fluorescence spectroscopies, paving the way to the development of novel high-performance optical sensors. All these devices find an impressive analogy in nearly-periodic photonic nanostructures present in several plants, animals and algae, which can represent a source of inspiration in the development and optimization of new artificial nano-optical systems. Here we present the main properties and applications of cutting-edge nanostructures starting from several examples of natural photonic architectures, up to the most recent technologies based on metallic and dielectric metasurfaces

    Bound-state in the continuum of a photonic crystal metasurface: a platform for ultrasensitive sensing and near field amplification

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    Abstract The localization of the electromagnetic field at the nanoscale can play a key role in many applications, such as sensing, spectroscopy and energy conversion. In the last years, great efforts have been performed to study and realize all-dielectric loss-free nanostructures to confine the radiation without the limits imposed by the plasmonic systems. Here we demonstrate that the field enhancement in proximity of a photonic crystal metasurface supporting bound states in the continuum can be explored to boost the light-matter interaction. We design and realize an innovative sensing scheme for bulk and surface measurement with ultra-high figure of merit and apply this new configuration for studying a specific protein-protein interaction. The recognition scheme can be coupled to a fluorescence-based sensing approach, which exploits the capability of the sensor to strongly enhance fluorescence signals. Our results provide new solutions for light manipulation at the nanoscale, especially for sensing and nonlinear optics applications

    Performance of Fatty Liver Index in Identifying Non-Alcoholic Fatty Liver Disease in Population Studies. A Meta-Analysis

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    Background. Fatty liver index (FLI) is a non-invasive tool used to stratify the risk of non-alcoholic fatty liver disease (NAFLD) in population studies; whether it can be used to exclude or diagnose this disorder is unclear. We conducted a meta-analysis to assess the prevalence of NAFLD in each FLI class and the performance of FLI in detecting NAFLD. Methods. Four databases were searched until January 2021 (CRD42021231367). Original articles included were those reporting the performance of FLI and adopting ultrasound, computed tomography, or magnetic resonance as a reference standard. The numbers of subjects with NAFLD in FLI classes <30, 30–60, and 60, and the numbers of subjects classified as true/false positive/negative when adopting 30 and 60 as cut-offs were extracted. A random-effects model was used for pooling data. Results. Ten studies were included, evaluating 27,221 subjects without secondary causes of fatty liver disease. The prevalence of NAFLD in the three FLI classes was 14%, 42%, and 67%. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for positive results, likelihood ratio for negative results, and diagnostic odds ratio were 81%, 65%, 53%, 84%, 2.3, 0.3, and 7.8 for the lower cut-off and 44%, 90%, 67%, 76%, 4.3, 0.6, and 7.3 for the higher cut-off, respectively. A similar performance was generally found in studies adopting ultrasound versus other imaging modalities. Conclusions. FLI showed an adequate performance in stratifying the risk of NAFLD. However, it showed only weak evidence of a discriminatory performance in excluding or diagnosing this disorder

    Impact of Different Operational Definitions of Sarcopenia on Prevalence in a Population-Based Sample: The Salus in Apulia Study

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    Background: In 2010, the European Working Group on Sarcopenia in Older People (EWGSOP1) issued its first operational definition to diagnose sarcopenia. This was updated in 2019 with a revised sequence of muscle mass and muscle strength (EWGSOP2). The aim of the study was to investigate the impact of these different operational definitions on sarcopenia prevalence in a representative population-based sample. Methods: For each algorithm, the prevalence of sarcopenia-related categories was calculated and related to sociodemographic and lifestyle variables, anthropometric parameters, and laboratory biomarkers. The present analysis used data from the Salus in Apulia Study (Italy, 740 subjects, mean age 75.5 ± 5.9 years, 54% women). Results: The application of the EWGSOP1 adapted algorithm resulted in 85% [95% confidence intervals (CI): 82–88%] non-sarcopenic subjects, 10% (95% CI: 8–12%) pre-sarcopenic subjects, and 5% (95% CI: 3–7%) sarcopenic/severe sarcopenic subjects. The sarcopenia-related categories were inversely related to weight and body mass index (BMI), particularly in overweight/obese subjects, and these categories showed favorable metabolic biomarkers. The EWGSOP2 algorithm yielded 73% (95% CI: 69–76%) non-sarcopenic subjects, 24% (95% CI: 21–27%) probably sarcopenic subjects, and 4% (95% CI: 2–5%) sarcopenic subjects. Conclusions: The present study identified BMI as a potential confounder of the prevalence estimates of sarcopenia-related categories in population-based settings with different EWGSOP operational definitions

    Liver Health and Dementia in an Italian Older Population: Findings From the Salus in Apulia Study

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    Objectives: Non-alcoholic fatty liver disease (NAFLD) currently affects a quarter of the global population. Systemic inflammation, metabolic syndrome, and coronary artery disease, all conditions associated with NAFLD, have also been related to cognitive dysfunction in older age. The present study aimed to investigate the relationship between NAFLD risk and a dementia diagnosis in a large population-based sample aged > 65 years. Methods: We selected 1,542 participants (723 men) from the Salus in Apulia Study. To assess the risk of fat distribution in the liver, we used the Fatty Liver Index (FLI). Dementia was diagnosed according to the American Psychiatric Association criteria (DSM-5). Results: The overall prevalence of dementia was 8.5% [95% confidence interval (CI): 7–10%]. Subjects with dementia were older [effect size (ES): −0.89, 95% CI: −1.07 to −0.70], had a lower level of education (ES:0.88, 95% CI:0.69–1.06), higher levels of gamma-glutamyl transferase (ES: −0.21, 95% CI: −0.39 to −0.03), lower levels of total cholesterol (ES: −0.24, 95% CI: −0.42 to −0.06) and low-density lipoprotein cholesterol (ES: −0.20, 95% CI: −0.38 to 0.02), and a higher FLI (ES: −0.22, 95% CI: −0.39 to −0.04). In the logistic regression model adjusted for age, sex, education, hypertension, diabetes mellitus, alcohol consumption, smoking habits, stroke, cholesterol, and Apo-E, a dementia diagnosis was positively associated with FLI > 60 [odds ratio (OR):1.81; standard error (SE): 0.53; 95% CI: 1.02–3.21]. Conclusion: Our findings suggested that an increased NAFLD risk may be associated to dementia and cognitive decline in older age. Considering the high NAFLD prevalence, the possible adverse disease effects on cognitive performance pose a health problem with significant social and economic implications

    Inter-society consensus for the use of inhaled corticosteroids in infants, children and adolescents with airway diseases

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    Background: In 2019, a multidisciplinary panel of experts from eight Italian scientific paediatric societies developed a consensus document for the use of inhaled corticosteroids in the management and prevention of the most common paediatric airways disorders. The aim is to provide healthcare providers with a multidisciplinary document including indications useful in the clinical practice. The consensus document was intended to be addressed to paediatricians who work in the Paediatric Divisions, the Primary Care Services and the Emergency Departments, as well as to Residents or PhD students, paediatric nurses and specialists or consultants in paediatric pulmonology, allergy, infectious diseases, and ear, nose, and throat medicine. Methods: Clinical questions identifying Population, Intervention(s), Comparison and Outcome(s) were addressed by methodologists and a general agreement on the topics and the strength of the recommendations (according to the GRADE system) was obtained following the Delphi method. The literature selection included secondary sources such as evidence-based guidelines and systematic reviews and was integrated with primary studies subsequently published. Results: The expert panel provided a number of recommendations on the use of inhaled corticosteroids in preschool wheezing, bronchial asthma, allergic and non-allergic rhinitis, acute and chronic rhinosinusitis, adenoid hypertrophy, laryngitis and laryngospasm. Conclusions: We provided a multidisciplinary update on the current recommendations for the management and prevention of the most common paediatric airways disorders requiring inhaled corticosteroids, in order to share useful indications, identify gaps in knowledge and drive future research
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