scholarly journals A photochemical determination of luminescence efficiency of upconverting nanoparticles

2019 ◽  
Author(s):  
Baptiste AMOUROUX ◽  
Clément ROUX ◽  
Jean-Claude MICHEAU ◽  
Fabienne GAUFFRE ◽  
Christophe M COUDRET
Keyword(s):  
Green Emission ◽  
Accurate Estimation ◽  
Luminescent Probes ◽  
Luminescence Efficiency ◽  
Visible Spectra ◽  
Non Linear ◽  
Precise Quantification ◽  
The Impact

Upconverting nanoparticles are a rising class of non-linear luminescent probes burgeoning since the beginning of the 2000’s, especially for their attractiveness in biology. However, the precise quantification of the light delivered remains a hot problem in order to estimate the impact in biology, resulting in the development by a few teams of sophisticated photophysical measurements (operable under NIR excitation). Here, we present the first attempt towards a simple and cheap photochemical approach consisting of a pseudo-actinometric characterization of the green emission of NaYF4:Yb,Er. Using the recently calibrated actinometer 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene operating in the green region of the visible spectra, we propose simple photochemical experiments to get an accurate estimation of the efficiency of these green-emitting “nanolamps”. The agreement of the collected data with the previous published results validates this approach.

scholarly journals A photochemical determination of luminescence efficiency of upconverting nanoparticles

2019 ◽  
Vol 15 ◽  
pp. 2671-2677 ◽  
Author(s):  
Baptiste Amouroux ◽  
Clément Roux ◽  
Jean-Claude Micheau ◽  
Fabienne Gauffre ◽  
Christophe Coudret
Keyword(s):  
Near Infrared ◽  
Green Emission ◽  
Accurate Estimation ◽  
Luminescent Probes ◽  
Luminescence Efficiency ◽  
Visible Spectra ◽  
Precise Quantification ◽  
Infrared Excitation

Upconverting nanoparticles are a rising class of non-linear luminescent probes burgeoning since the beginning of the 2000’s, especially for their attractiveness in theranostics. However, the precise quantification of the light delivered remains a hot problem in order to estimate their impact on the biological medium. Sophisticated photophysical measurements under near infrared excitation have been developed only by few teams. Here, we present the first attempt towards a simple and cheap photochemical approach consisting of an actinometric characterization of the green emission of NaYF4:Yb,Er nanoparticles. Using the recently calibrated actinometer 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene operating in the green region of the visible spectra, we propose a simple photochemical experiment to get an accurate estimation of the efficiency of these green-emitting “nanolamps”. The agreement of the collected data with the previous published results validates this approach.

scholarly journals Asteroseismic potential of CHEOPS

2018 ◽  
Vol 620 ◽  
pp. A203 ◽  
Author(s):  
A. Moya ◽  
S. Barceló Forteza ◽  
A. Bonfanti ◽  
S. J. A. J. Salmon ◽  
V. Van Grootel ◽  
...  
Keyword(s):  
Time Series ◽  
Main Sequence ◽  
Uncertainty Reduction ◽  
Light Curves ◽  
Accuracy And Precision ◽  
Mass Uncertainty ◽  
The Impact ◽  
Host Stars

Context. Asteroseismology has been impressively boosted during the last decade mainly thanks to space missions such as Kepler/K2 and CoRoT. This has a large impact, in particular, in exoplanetary sciences since the accurate characterization of the exoplanets is convoluted in most cases with the characterization of their hosting star. In the decade before the expected launch of the ESA mission PLATO 2.0, only two important missions will provide short-cadence high-precision photometric time-series: NASA–TESS and ESA–CHEOPS missions, both having high capabilities for exoplanetary sciences. Aims. In this work we want to explore the asteroseismic potential of CHEOPS time-series. Methods. Following the works estimating the asteroseismic potential of Kepler and TESS, we have analysed the probability of detecting solar-like pulsations using CHEOPS light-curves. Since CHEOPS will collect runs with observational times from hours up to a few days, we have analysed the accuracy and precision we can obtain for the estimation of νmax. This is the only asteroseismic observable we can recover using CHEOPS observations. Finally, we have analysed the impact of knowing νmax in the characterization of exoplanet host stars. Results. Using CHEOPS light-curves with the expected observational times we can determine νmax for massive G and F-type stars from late main sequence (MS) on, and for F, G, and K-type stars from post-main sequence on with an uncertainty lower than a 5%. For magnitudes V <  12 and observational times from eight hours up to two days, the HR zone of potential detectability changes. The determination of νmax leads to an internal age uncertainty reduction in the characterization of exoplanet host stars from 52% to 38%; mass uncertainty reduction from 2.1% to 1.8%; radius uncertainty reduction from 1.8% to 1.6%; density uncertainty reduction from 5.6% to 4.7%, in our best scenarios.

scholarly journals The Diagnosis and Clinical Significance of Paragangliomas in Unusual Locations

2018 ◽  
Vol 7 (9) ◽  
pp. 280 ◽  
Author(s):  
Sylvia Asa ◽  
Shereen Ezzat ◽  
Ozgur Mete
Keyword(s):  
Malignant Disease ◽  
Correct Diagnosis ◽  
Neuroendocrine Neoplasms ◽  
Clinical Implications ◽  
Bladder Tumors ◽  
Primary Tumors ◽  
Anatomic Locations ◽  
The Impact

Paragangliomas are neuroendocrine neoplasms, derived from paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly identified in the head and neck, being most frequent in the carotid body, followed by jugulotympanic paraganglia, vagal nerve and ganglion nodosum, as well as laryngeal paraganglia. Abdominal sites include the well-known urinary bladder tumors that originate in the Organ of Zuckerkandl. However, other unusual sites of origin include peri-adrenal, para-aortic, inter-aortocaval, and paracaval retroperitoneal sites, as well as tumors in organs where they may not be expected in the differential diagnosis of neuroendocrine neoplasms, such as thyroid, parathyroid, pituitary, gut, pancreas, liver, mesentery, lung, heart and mediastinum. The distinction of these lesions from epithelial neuroendocrine neoplasms is critical for several reasons. Firstly, the determination of clinical and biochemical features is different from that used for epithelial neuroendocrine tumors. Secondly, the genetic implications are different, since paragangliomas/pheochromocytomas have the highest rate of germline susceptibility at almost 40%. Finally, the characterization of metastatic disease is unique in these highly syndromic lesions. In this review, we summarize updated concepts by outlining the spectrum of anatomic locations of paragangliomas, the importance of morphology in establishing the correct diagnosis, the clinical implications for management, and the impact of genetics on the distinction between multifocal primary tumors compared with malignant disease.

scholarly journals Characteristic diffuse scattering from distinct line roughnesses

2017 ◽  
Vol 50 (6) ◽  
pp. 1766-1772 ◽  
Author(s):  
Analía Fernández Herrero ◽  
Mika Pflüger ◽  
Jürgen Probst ◽  
Frank Scholze ◽  
Victor Soltwisch
Keyword(s):  
Extreme Ultraviolet ◽  
Structural Elements ◽  
Line Edge Roughness ◽  
Optical Elements ◽  
Angle Scattering ◽  
Edge Roughness ◽  
Angular Scattering ◽  
The Impact

Lamellar gratings are widely used diffractive optical elements; gratings etched into Si can be used as structural elements or prototypes of structural elements in integrated electronic circuits. For the control of the lithographic manufacturing process, a rapid in-line characterization of nanostructures is indispensable. Numerous studies on the determination of regular geometry parameters of lamellar gratings from optical and extreme ultraviolet (EUV) scattering highlight the impact of roughness on the optical performance as well as on the reconstruction of these structures. Thus, a set of nine lamellar Si gratings with a well defined line edge roughness or line width roughness were designed. The investigation of these structures using EUV small-angle scattering reveals a strong correlation between the type of line roughness and the angular scattering distribution. These distinct scattering patterns open new paths for the unequivocal characterization of such structures by EUV scatterometry.

scholarly journals Elemental concentration via portable x-ray fluorescence spectrometry: Assessing the impact of water content

2019 ◽  
Vol 43 ◽  
Author(s):  
Monna Lysa Teixeira Santana ◽  
Geila Santos Carvalho ◽  
Luiz Roberto Guimarães Guilherme ◽  
Nilton Curi ◽  
Bruno Teixeira Ribeiro
Keyword(s):  
Water Content ◽  
Atomic Number ◽  
Certified Reference Materials ◽  
Chemical Characterization ◽  
X Ray ◽  
Influence Of Water ◽  
Corrected Data ◽  
The Impact

ABSTRACT Portable X-ray fluorescence (pXRF) analysis can be considered one of the main recent advances for chemical characterization of earth materials. The water content of the samples can affect the pXRF performance. As a novelty, we aimed to establish relationships (linear regression) between the effect of water content on pXRF results and atomic number (Z) of the elements. Three certified reference materials (CRM) were investigated: OREAS 100a, OREAS 101a, and OREAS 101b. These materials were saturated (0.68 g g-1) with distilled water and left to air-dry naturally. During the drying, the elemental concentrations (C) were determined at different water contents using a pXRF spectrometer. For each water content, the ratio Cwet/Cdry was determined and plotted against the water content. The attenuation coefficient (σ) was also determined. High σ values mean more influence of water content upon measurement element concentration. The obtained recovery rates allowed a qualitative determination. The concentration for the most elements reduced linearly with increasing water content. A predictable behavior of the water content on pXRF results as function of atomic number was not found. Elements identified by Lα spectral line with highest Z were more impacted by water content than elements identified by Kα line with lowest Z. Ti, Cr and Fe was not significantly influenced by water content, and Sr was the most impacted. Our findings contribute to decision-making before characterization earth materials via pXRF, obliging the use of dry samples for determination of impacted elements or by using moisture-corrected data.

scholarly journals NMR Tracing of Food Geographical Origin: The Impact of Seasonality, Cultivar and Production Year on Data Analysis

Separations ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 230
Author(s):  
Olimpia Masetti ◽  
Angela Sorbo ◽  
Luigi Nisini
Keyword(s):  
Data Analysis ◽  
Nmr Spectroscopy ◽  
Geographical Origin ◽  
Soil Composition ◽  
Multivariate Statistical ◽  
Preliminary Study ◽  
The Impact

The traceability of typical foodstuffs is necessary to protect high quality of traditional products. It is well-known that several factors could influence metabolites content in certified foods, but soil composition, altitude, latitude and coded production protocols constitute the territorial conditions responsible for the peculiar organoleptic and nutritional properties of labelled foods. Instead, regardless of origin, seasonality, cultivar, collection year can affect all agricultural products, so it is appropriate to include them in data analysis in order to obtain a correct interpretation of the differences linked to growing areas alone. Therefore, it is useful to use a flexible all-round technique, and NMR spectroscopy coupled with multivariate statistical analysis is considered a powerful means of assessing food authenticity. The purpose of this review is to investigate the relevance of year, cultivar, and seasonal period in the determination of food geographical origin using NMR spectroscopy. The strategy for testing these three factors may differ from author to author, but a preliminary study of cultivar or collection year effects on NMR spectra is the most popular method before starting the geographical characterization of samples. In summary, based on the available literature, the most significant influence is due to cultivar, followed by harvesting year, however seasonality is not considered a source of variability in data analysis.

scholarly journals Identification and Physicochemical Characterization of a New Allergen from Ascaris lumbricoides

2020 ◽  
Vol 21 (24) ◽  
pp. 9761
Author(s):  
Velky Ahumada ◽  
María Manotas ◽  
Josefina Zakzuk ◽  
Lorenz Aglas ◽  
Sandra Coronado ◽  
...  
Keyword(s):  
Ascaris Lumbricoides ◽  
Immunoglobulin E ◽  
Physicochemical Characterization ◽  
Allergic Diseases ◽  
Specific Ige ◽  
Allergenic Activity ◽  
The Impact ◽  
Helical Folding

To analyze the impact of Ascaris lumbricoides infection on the pathogenesis and diagnosis of allergic diseases, new allergens should be identified. We report the identification of a new Ascaris lumbricoides allergen, Asc l 5. The aim of this study was to evaluate the physicochemical and immunological features of the Asc l 5 allergen. We constructed an A. lumbricoides cDNA library and Asc l 5 was identified by immunoscreening. After purification, rAsc l 5 was physicochemically characterized. Evaluation of its allergenic activity included determination of Immunoglobulin E (IgE) binding frequency (in two populations: 254 children and 298 all-age subjects), CD203c based-basophil activation tests (BAT) and a passive cutaneous anaphylaxis (PCA) mouse model. We found by amino acid sequence analysis that Asc l 5 belongs to the SXP/RAL-2 protein family of nematodes. rAsc l 5 is a monomeric protein with an alpha-helical folding. IgE sensitization to rAsc l 5 was around 52% in general population; positive BAT rate was 60%. rAsc l 5 induced specific IgE production in mice and a positive PCA reaction. These results show that Asc l 5 has structural and immunological characteristics to be considered as a new allergen from A. lumbricoides.

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