1,617 research outputs found
Formulación que comprende micropartículas de silicio como pigmento absorbente de la radiación UV-visible y reflectante de la radiación IR
La presente invención se refiere a una formulación caracterizada porque comprende micropartículas de silicio con un tamaño comprendido entre 0,1 μm y 50 μm de diámetro, así como a su uso como pigmento absorbente de la radiación UV-visible y reflectante de la radiación IR.Peer reviewedConsejo Superior de Investigaciones Científicas, Universidad Politécnica de Valencia, ONA Investigación S.L.A1 Solicitud de patente con informe sobre el estado de la técnic
Silicon nanoparticles as Raman scattering enhancers
[EN] In this communication we demonstrate the large amplification values of the Raman signal of organic molecules attached to silicon nanoparticles (SiNPs). Light induced Mie resonances of high refractive index particles generate strong evanescent electromagnetic (EM) fields, thus boosting the Raman signal of species attached to the nanoparticles. The interest of this process is justified by the wide range of experimental configurations that can be implemented including photonic crystals, the sharp spectral resonances easily tuneable with the particle size, the biocompatibility and biodegradability of silicon, and the possibility of direct analysis of molecules that do not contain functional groups with high affinity for gold and silver. Additionally, silicon nanoparticles present stronger field enhancement due to Mie resonances at larger sizes than gold.The authors acknowledge financial support from the following projects FIS2009-07812, MAT2012-35040, Consolider 2007-0046 Nano light, PROMETEO/2010/043, CTQ2011-23167, and Cross-SEAS, FP7 MC-IEF 329131. L. S. thanks the financial support from the MINECO (Estancias de profesores e investigadores extranjeros en centros espanoles) fellowship program.Rodríguez, M.; Shi, L.; Lu, X.; Korgel, B.; Alvarez -Puebla, R.; Meseguer Rico, FJ. (2014). Silicon nanoparticles as Raman scattering enhancers. Nanoscale. 6(11):5666-5670. https://doi.org/10.1039/c4nr00593gS5666567061
Packing confined hard spheres denser with adaptive prism phases
[EN] We show that hard spheres confined between two parallel hard plates pack denser with periodic adaptive prismatic structures which are composed of alternating prisms of spheres. The internal structure of the prisms adapts to the slit height which results in close packings for a range of plate separations, just above the distance where three intersecting square layers fit exactly between the plates. The adaptive prism phases are also observed in real-space experiments on confined sterically stabilized colloids and in Monte Carlo simulations at finite pressure. © 2012 American Physical Society.We thank Elvira Bonet, Moises Garin, and Kevin Mutch for helpful discussions. This work was partially supported by the DFG within the SFB TR6 (Project D1), and by the Spanish CICyT Projects FIS2009-07812 and PROMETEO/2010/043. F. R.-M. acknowledges the support from the EU Marie Curie Project APPCOPTOR-275150 (FP7-PEOPLE-2010-IEF).Oguz, EC.; Merechal, M.; Ramiro Manzano, F.; Rodríguez, M.; Messina, R.; Meseguer Rico, FJ.; Loewen, H. (2012). Packing confined hard spheres denser with adaptive prism phases. Physical Review Letters. 109(21):218301-1-218301-5. https://doi.org/10.1103/PhysRevLett.109.218301S218301-1218301-51092
Monodisperse silicon nanocavities and photonic crystals with magnetic response in the optial region
[EN] It is generally accepted that the magnetic component of light has a minor role in the light-matter interaction. The recent discovery of metamaterials has broken this traditional understanding, as both the electric and the magnetic field are key ingredients in metamaterials. The top-down technology used so far employs noble metals with large intrinsic losses. Here we report on a bottom-up approach for processing metamaterials based on suspensions of monodisperse full dielectric silicon nanocavities with a large magnetic response in the near-infrared region. Experimental results and theory show that silicon-colloid-based liquid suspensions and photonic crystals made of two-dimensional arrays of particles have strong magnetic response in the near-infrared region with small optical losses. Our findings might have important implications in the bottom-up processing of large-area low-loss metamaterials working in the near-infrared region.We acknowledge financial support from the following projects FIS2009-07812, Consolider 2007-0046 Nanolight, the PROMETEO/2010/043 and the Robert A. Welch Foundation (F-1464). L.S. thanks the financial support from the MINECO (Estancias de profesores e investigadores extranjeros en centros espanoles) fellowship program.Shi, L.; Harris, JT.; Fenollosa Esteve, R.; Rodríguez, M.; Lu, X.; Korgel, B.; Meseguer Rico, FJ. (2013). Monodisperse silicon nanocavities and photonic crystals with magnetic response in the optial region. Nature Communications. 4:419041-419047. https://doi.org/10.1038/ncomms29344190414190474Landau, L. D. & Lifshitz, E. M. . Electrodynamics of Continuous Media Oxford, UK (1960) .Smith, D. R., Pendry, J. B. & Wiltshire, M. C. K. . Metamaterials and negative refractive index. Science 305, 788–792 (2004) .Soukoulis, C. 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ACS Nano 6, 837–842 (2012) .Shi, L., Xifre-Perez, E., Garcia de Abajo, F. J. & Meseguer, F. . Looking through the mirror: optical microcavity-mirror image photonic interaction. Opt. Express 20, 11247–11255 (2012) .Shi, L. & Meseguer, F. . Magnetic interaction in all silicon waveguide spherical coupler device. Opt. Express 20, 22617–22626 (2012) .Shi, L., Tuzer, T. U., Fenollosa, R. & Meseguer, F. . A new dielectric metamaterial building block with a strong magnetic response below 1.5 micrometers region. Silicon colloids nanocavities. Adv. Mater. 20, 5934–5938 (2012) .Evlyukhin, A. B., Reinhardt, C., Seidel, A., Lukyanchuk, B. S. & Chichkov, B. . Optical response features of Si-nanoparticle arrays. Phys. Rev. B 82, 045404 (2010) .Krasnok, A. E., Miroshnichenko, A. E., Belov, P. A. & Kivshar, Y. S. . Huygens optical elements and Yagi-Uda nanoantennas based on dielectric nanoparticles. JETP Lett. 94, 593–598 (2011) .Krasnok, A. E., Miroshnichenko, A. E., Belov, P. A. & Kivshar, Y. S. . 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Characteristics of Medical Research News Reported on Front Pages of Newspapers
Background: The placement of medical research news on a newspaper's front page is intended to gain the public's attention, so it is important to understand the source of the news in terms of research maturity and evidence level. Methodology/Principal Findings: We searched LexisNexis to identify medical research reported on front pages of major newspapers published from January 1, 2000 to December 31, 2002. We used MEDLINE and Google Scholar to find journal articles corresponding to the research, and determined their evidence level. Of 734 front-page medical research stories identified, 417 (57%) referred to mature research published in peer-reviewed journals. The remaining 317 stories referred to preliminary findings presented at scientific or press meetings; 144 (45%) of those stories mentioned studies that later matured (i.e. were published in journals within 3 years after news coverage). The evidence-level distribution of the 515 journal articles quoted in news stories reporting on mature research (3% level I, 21% level II, 42% level III, 4% level IV, and 31% level V) differed from that of the 170 reports of preliminary research that later matured (1%, 19%, 35%, 12%, and 33%, respectively; chi-square test, P = .0009). No news stories indicated evidence level. Fewer than 1 in 5 news stories reporting preliminary findings acknowledged the preliminary nature of their content. Conclusions/Significance: Only 57% of front-page stories reporting on medical research are based on mature research, which tends to have a higher evidence level than research with preliminary findings. Medical research news should be clearly referenced and state the evidence level and limitations to inform the public of the maturity and quality of the source. © 2009 Lai, Lane.published_or_final_versio
Genetic, Phenotypic, and Interferon Biomarker Status in ADAR1-Related Neurological Disease
International audienceWe investigated the genetic, phenotypic, and interferon status of 46 patients from 37 families with neurological disease due to mutations in ADAR1. The clinicoradiological phenotype encompassed a spectrum of Aicardi–Goutières syndrome, isolated bilateral striatal necrosis, spastic paraparesis with normal neuroimaging, a progressive spastic dystonic motor disorder, and adult-onset psychological difficulties with intracranial calcification. Homozygous missense mutations were recorded in five families. We observed a p.Pro193Ala variant in the heterozygous state in 22 of 23 families with compound heterozygous mutations. We also ascertained 11 cases from nine families with a p.Gly1007Arg dominant-negative mutation, which occurred de novo in four patients, and was inherited in three families in association with marked phenotypic variability. In 50 of 52 samples from 34 patients, we identified a marked upregulation of type I interferon-stimulated gene transcripts in peripheral blood, with a median interferon score of 16.99 (interquartile range [IQR]: 10.64–25.71) compared with controls (median: 0.93, IQR: 0.57–1.30). Thus, mutations in ADAR1 are associated with a variety of clinically distinct neurological phenotypes presenting from early infancy to adulthood, inherited either as an autosomal recessive or dominant trait. Testing for an interferon signature in blood represents a useful biomarker in this context
Exploring the link between MORF4L1 and risk of breast cancer.
INTRODUCTION: Proteins encoded by Fanconi anemia (FA) and/or breast cancer (BrCa) susceptibility genes cooperate in a common DNA damage repair signaling pathway. To gain deeper insight into this pathway and its influence on cancer risk, we searched for novel components through protein physical interaction screens. METHODS: Protein physical interactions were screened using the yeast two-hybrid system. Co-affinity purifications and endogenous co-immunoprecipitation assays were performed to corroborate interactions. Biochemical and functional assays in human, mouse and Caenorhabditis elegans models were carried out to characterize pathway components. Thirteen FANCD2-monoubiquitinylation-positive FA cell lines excluded for genetic defects in the downstream pathway components and 300 familial BrCa patients negative for BRCA1/2 mutations were analyzed for genetic mutations. Common genetic variants were genotyped in 9,573 BRCA1/2 mutation carriers for associations with BrCa risk. RESULTS: A previously identified co-purifying protein with PALB2 was identified, MRG15 (MORF4L1 gene). Results in human, mouse and C. elegans models delineate molecular and functional relationships with BRCA2, PALB2, RAD51 and RPA1 that suggest a role for MRG15 in the repair of DNA double-strand breaks. Mrg15-deficient murine embryonic fibroblasts showed moderate sensitivity to γ-irradiation relative to controls and reduced formation of Rad51 nuclear foci. Examination of mutants of MRG15 and BRCA2 C. elegans orthologs revealed phenocopy by accumulation of RPA-1 (human RPA1) nuclear foci and aberrant chromosomal compactions in meiotic cells. However, no alterations or mutations were identified for MRG15/MORF4L1 in unclassified FA patients and BrCa familial cases. Finally, no significant associations between common MORF4L1 variants and BrCa risk for BRCA1 or BRCA2 mutation carriers were identified: rs7164529, Ptrend = 0.45 and 0.05, P2df = 0.51 and 0.14, respectively; and rs10519219, Ptrend = 0.92 and 0.72, P2df = 0.76 and 0.07, respectively. CONCLUSIONS: While the present study expands on the role of MRG15 in the control of genomic stability, weak associations cannot be ruled out for potential low-penetrance variants at MORF4L1 and BrCa risk among BRCA2 mutation carriers.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Autoantibodies against type I IFNs in patients with critical influenza pneumonia
In an international cohort of 279 patients with hypoxemic influenza pneumonia, we identified 13 patients (4.6%) with autoantibodies neutralizing IFN-alpha and/or -omega, which were previously reported to underlie 15% cases of life-threatening COVID-19 pneumonia and one third of severe adverse reactions to live-attenuated yellow fever vaccine. Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-alpha 2 alone (five patients) or with IFN-omega (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia. Nine and four patients had antibodies neutralizing high and low concentrations, respectively, of IFN-alpha 2, and six and two patients had antibodies neutralizing high and low concentrations, respectively, of IFN-omega. The patients' autoantibodies increased influenza A virus replication in both A549 cells and reconstituted human airway epithelia. The prevalence of these antibodies was significantly higher than that in the general population for patients 70 yr of age (3.1 vs. 4.4%, P = 0.68). The risk of critical influenza was highest in patients with antibodies neutralizing high concentrations of both IFN-alpha 2 and IFN-omega (OR = 11.7, P = 1.3 x 10(-5)), especially those <70 yr old (OR = 139.9, P = 3.1 x 10(-10)). We also identified 10 patients in additional influenza patient cohorts. Autoantibodies neutralizing type I IFNs account for similar to 5% of cases of life-threatening influenza pneumonia in patients <70 yr old
Gamma-ray and radio properties of six pulsars detected by the fermi large area telescope
We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models
Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs
Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population
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