109 research outputs found
Fabrication and characterization of silver inverse opals
Artificial structures with two- or three-dimensional arrangement of materials (photonic crystals) are being considered in recent days a key
structure for the fabrication of advanced optical devices with the potential to substitute present electronics by all-photonic systems in the near
future. Special interest has also arisen for their use as chemical sensors and in the fabrication of solar cells. In this work, a fabrication process for
silver artificial structures from a colloidal solution of polystyrene spheres is presented. The colloidal spheres are arranged onto a glass substrate to
form an artificial opal that is subsequently infiltrated with silver.
Additionally, the structural and optical properties of the fabricated structures are studied. The structural characterization of the opals shows good
order in the long scale. Reflectance measurements of these samples present a reflection peak centred around 800 nm. SEM images of the silver
infiltrated opals show that the infiltration has been carried out successfully. Even so, the optical characterization of the infiltrated samples shows a
big intensification of the original reflectivity with a displacement of only few nanometres from the original peak. After the removal of the spheres,
the samples show total inversion.
© 2006 Elsevier B.V. All rights reserved
A systematic review of economic evaluations of interventions targeting childhood overweight and obesity
This systematic review critically appraised and synthesized evidence from economic evaluations of interventions targeting childhood excess weight. We conducted systematic searches in 11 databases from inception to April 19, 2023. Studies were eligible if they evaluated interventions targeting children up to 18âyears and the study intervention(s) targeted childhood excess weight or sought to improve diet or physical activity, regardless of the type of economic evaluation or the underpinning study design. We synthesized evidence using narrative synthesis methods. One-hundred fifty-one studies met the eligibility criteria and were classified into three groups based on the intervention approach: prevention-only (13 studies), prevention and treatment (100 studies), and treatment-only (38 studies). The predominant setting and study design differed considerably between the three groups of studies. However, compared with usual care, most interventions were deemed cost-effective. The study participants' ages, sex, and socioeconomic status were crucial to intervention cost-effectiveness. Interventions whose effects were projected beyond childhood, such as bariatric surgery, lower protein infant formula, and home-based general practitioner consultations, tended to be cost-effective. However, cost-effectiveness was sensitive to the assumptions underlying the persistence and intensity of such effects. Our findings can inform future recommendations on the conduct of economic evaluations of interventions targeting childhood overweight and obesity, as well as practice and policy recommendations
Covid-19 in children with down syndrome: Data from the trisomy 21 research society survey
Adults with Down Syndrome (DS) are at higher risk for severe outcomes of coronavirus disease 2019 (COVID-19) than the general population, but evidence is required to understand the risks for children with DS, which is necessary to inform COVID-19 shielding advice and vaccination priorities. We aimed to determine the epidemiological and clinical characteristics of COVID-19 in children with DS. Using data from an international survey obtained from a range of countries and control data from the United States, we compared the prevalence of symptoms and medical complications and risk factors for severe outcomes between DS and non-DS paediatric populations with COVID-19. Hospitalised COVID-19 patients <18 years with DS had a higher incidence of respiratory symptoms, fever, and several medical complications from COVID-19 than control patients without DS <18 years. Older age, obesity, and epilepsy were significant risk factors for hospitalisation among paediatric COVID-19 patients with DS, and age and thyroid disorder were significant risk factors for acute respiratory distress syndrome. Mortality rates were low in all paediatric COVID-19 patients (with and without DS), contrasting with previous findings in adults with DS (who exhibit higher mortality than those without DS). Children with DS are at increased risk for more severe presentations of COVID-19. Efforts should be made to ensure the comprehensive and early detection of COVID-19 in this population and to identify children with DS who present comorbidities that pose a risk for a severe course of COVID-19. Our results emphasize the importance of vaccinating children with DS as soon as they become eligible
Medical vulnerability of individuals with Down syndrome to severe COVID-19âdata from the Trisomy 21 Research Society and the UK ISARIC4C survey
Background: Health conditions, immune dysfunction, and premature aging associated with trisomy 21 (Down syndrome, DS) may impact the clinical course of COVID-19. /
Methods: The T21RS COVID-19 Initiative launched an international survey for clinicians or caregivers on patients with COVID-19 and DS. Data collected between April and October 2020 (N=1046) were analysed and compared with the UK ISARIC4C survey of hospitalized COVID-19 patients with and without DS. /
Findings: The mean age of COVID-19 patients with DS in the T21RS survey was 29 years (SD = 18). Similar to the general population, the most frequent signs and symptoms of COVID-19 were fever, cough, and shortness of breath. Joint/muscle pain and vomiting or nausea were less frequent (p < 0.01), whereas altered consciousness/confusion were more frequent (p < 0.01). Risk factors for hospitalization and mortality were similar to the general population with the addition of congenital heart defects as a risk factor for hospitalization. Mortality rates showed a rapid increase from age 40 and were higher in patients with DS (T21RS DS versus non-DS patients: risk ratio (RR) = 3.5 (95%-CI=2.6;4.4), ISARIC4C DS versus non-DS patients: RR = 2.9 (95%-CI=2.1;3.8)) even after adjusting for known risk factors for COVID-19 mortality. /
Interpretation: Leading signs/symptoms of COVID-19 and risk factors for severe disease course are similar to the general population. However, individuals with DS present significantly higher rates of medical complications and mortality, especially from age 40. /
Funding: Down Syndrome Affiliates in Action, DSMIG-USA, GiGi's Playhouse, Jerome Lejeune Foundation, LuMind IDSC Foundation, The Matthew Foundation, NDSS, National Task Group on Intellectual Disabilities and Dementia Practices
Opioid medication use and blood DNA methylation:epigenome-wide association meta-analysis
Aim: To identify differential methylation related to prescribed opioid use. Methods: This study examined whether blood DNA methylation, measured using Illumina arrays, differs by recent opioid medication use in four population-based cohorts. We meta-analyzed results (282 users; 10,560 nonusers) using inverse-variance weighting. Results: Differential methylation (false discovery rate \u3c0.05) was observed at six CpGs annotated to the following genes: KIAA0226, CPLX2, TDRP, RNF38, TTC23 and GPR179. Integrative epigenomic analyses linked implicated loci to regulatory elements in blood and/or brain. Additionally, 74 CpGs were differentially methylated in males or females. Methylation at significant CpGs correlated with gene expression in blood and/or brain. Conclusion: This study identified DNA methylation related to opioid medication use in general populations. The results could inform the development of blood methylation biomarkers of opioid use
The Index Bundle and Multiparameter Bifurcation for Discrete Dynamical Systems
We develop a K-theoretic approach to multiparameter bifurcation theory of homoclinic solutions of discrete non-autonomous dynamical systems from a branch of stationary solutions. As a byproduct we obtain a family index theorem for asymptotically hyperbolic linear dynamical systems which is of independent interest. In the special case of a single parameter, our bifurcation theorem weakens the assumptions in previous work by Pejsachowicz and the first author
Opioid medication use and blood DNA methylation: epigenome-wide association meta-analysis.
This is the final version. Available from Future Medicine via the DOI in this record.âŻData sharing statement:
Complete meta-analysis results can be found at Zenodo 10.5281/zenodo.7545108.Aim: To identify differential methylation related to prescribed opioid use. Methods: This study examined whether blood DNA methylation, measured using Illumina arrays, differs by recent opioid medication use in four population-based cohorts. We meta-analyzed results (282 users; 10,560 nonusers) using inverse-variance weighting. Results: Differential methylation (false discovery rate <0.05) was observed at six CpGs annotated to the following genes: KIAA0226, CPLX2, TDRP, RNF38, TTC23 and GPR179. Integrative epigenomic analyses linked implicated loci to regulatory elements in blood and/or brain. Additionally, 74 CpGs were differentially methylated in males or females. Methylation at significant CpGs correlated with gene expression in blood and/or brain. Conclusion: This study identified DNA methylation related to opioid medication use in general populations. The results could inform the development of blood methylation biomarkers of opioid use.National Institute of Healt
Epigenome-wide meta-analysis of prenatal maternal stressful life events and newborn DNA methylation.
This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this recordCode availability:
The code used for this EWAS meta-analysis is available from the corresponding authors upon reasonable request.Prenatal maternal stressful life events are associated with adverse neurodevelopmental outcomes in offspring. Biological mechanisms underlying these associations are largely unknown, but DNA methylation likely plays a role. This meta-analysis included twelve non-overlapping cohorts from ten independent longitudinal studies (Nâ=â5,496) within the international Pregnancy and Childhood Epigenetics consortium to examine maternal stressful life events during pregnancy and DNA methylation in cord blood. Children whose mothers reported higher levels of cumulative maternal stressful life events during pregnancy exhibited differential methylation of cg26579032 in ALKBH3. Stressor-specific domains of conflict with family/friends, abuse (physical, sexual, and emotional), and death of a close friend/relative were also associated with differential methylation of CpGs in APTX, MyD88, and both UHRF1 and SDCCAG8, respectively; these genes are implicated in neurodegeneration, immune and cellular functions, regulation of global methylation levels, metabolism, and schizophrenia risk. Thus, differences in DNA methylation at these loci may provide novel insights into potential mechanisms of neurodevelopment in offspring.Medical Research Council and Wellcome Trus
Southward displacement of the North Atlantic Subtropical Gyre circulation system during North Atlantic cold spells
Key Points:
- Rapid subsurface oceanographic change in the tropical W Atlantic reflect shifting Subtropical Gyre
- Subsurface warming responds to deglacial AMOC perturbations (Heinrich Stadials 2, 1, and the Younger Dryas)
- Southward propagation of Salinity Maximum Water during Northern Hemisphere cold spells shift the mixing zone of tropical and subtropical waters
During times of deglacial Atlantic Meridional Overturning Circulation (AMOC) perturbations, the tropical Atlantic experienced considerable warming at subsurface levels. Coupled oceanâatmosphere simulations corroborate the tight teleconnection between the tropical Atlantic and climate change at high northern latitudes, but still underestimate the relevance of the subsurface N Atlantic Subtropical Gyre (STG) for heat and salt storage and its sensitivity to rapid climatic change.
We here reconstruct vertical and lateral temperature and salinity gradients in the tropical W Atlantic and the Caribbean over the last 30 kyrs, based on planktic deep and shallow dwelling foraminiferal Mg/Ca and ÎŽ18Oârecords. The rapid and large amplitude subsurface changes illustrate a dynamic STG associated with abrupt shifts of North Atlantic hydrographic and atmospheric regimes. During full glacial conditions, the STG has been shifted southward while intensified Ekmanâdownwelling associated to strengthened trade winds fostered the formation of warm and saline Salinity Maximum Water (SMW). The southward propagation of SMW was facilitated by the glacially eastward deflected North Brazil Current. During periods of significant AMOC perturbations (Heinrich Stadials 1, and the Younger Dryas), extreme subsurface warming by ~6°C led to diminished lateral subsurface temperature gradients. Coevally, a deep thermocline suggests that SMW fully occupied the subsurface tropical W Atlantic and that the STG reached its southernmost position. During the Holocene, modernâlike conditions gradually developed with the northward retreat of SMW and the development of a strong thermocline ridge between the Subtropical Gyre and the tropical W Atlantic
- âŠ