103 research outputs found

    On-line carbon dots synthesis using flow injection analysis. Application to aluminium determination in water samples

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    An on-line synthesis of CDots is proposed for the first time, using the flow injection analysis (FIA) technique, which was coupled, in a single system, to the analytical determination of aluminium in water samples. The nanoparticles were obtained from the carbonization of glucose and iron(III) in an acidic medium, and their photoluminescence increased in the presence of aluminium ions. Under optimal experimental conditions, the proposed method has shown an acceptable linearity range –between 0.04 and 3.0 mg L−1 (R2 = 0.9999) – and a detection limit of 0.007 mg L−1. The analysis of drinking water and groundwater samples showed good accuracy (recoveries ranged between 91 – 113%) and RSD% < 13. The on-line system exhibited a high sample throughput (36 h−1), since no incubation time was required.Financial support from Universidad Nacional del Sur (PGI 24/Q099 and 24/Q123, CONICET 11220200102603CO, CONICET 11220200103198CO and the ANPCyT PICT-2019-04458 (2021-2023) is gratefully acknowledged. This research was part of the Ph.D. thesis of Damian Uriarte, which was supported by a doctoral grant funded by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). M. Garrido and C.E. Domini wish to thank CONICET

    Trade patterns, trade balances and idiosyncratic shocks

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    International Macroeconomics has long sought an explanation for current account fluctuations that matches the data. The approaches have typically focused on better models and new macroeconomic variables. We demonstrate the limitations of this approach by showing that idiosyncratic shocks are an important cause of macroeconomic volatility even for large countries. When explaining these fluctuations, standard macroeconomic models generally assume that firms are small and that their microeconomic shocks cancel out. We show that the high degree of concentration of bilateral trade flows means that idiosyncratic shocks can have a significant impact on aggregate economic fluctuations. We theoretically develop a descomposition components. Taking the model to data on bilateral trade flows from 1970 to 1997, we find that the most comprehensive macroeconomic model can only account for at most half of the observed variance in trade account volumes of each country. Thus, this paper highlights the importance of considering disaggregated data when modeling the current accoun

    Intellectual Property-Related Preferential Trade Agreements and Offshoring to Developing Countries

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    International standards in the protection of intellectual property rights (IPRs) are increasingly guided by bilateral and regional preferential trade agreements (PTAs). In this paper, we estimate the effect of these IP-related PTAs on US offshoring behavior in developing countries. We utilize a difference-in-difference empirical methodology that addresses several possible sources of endogeneity and exploits industry variation in the importance of IPRs to identify the effect of these PTA-induced IPR reforms. We find that IP-related PTAs are associated with a substantial increase in US offshoring in IPR-intensive industries relative to non-IPR-intensive industries. This increase occurs both within the boundaries of the multinational firm and through arm’s-length contracts with domestic firms. We do not find strong evidence for a compositional shift towards either type of offshoring. These findings provide direct empirical evidence that PTA-induced IPR reform stimulates multinational activity in developing countries

    Analysis of metals and phosphorus in biodiesel B100 from different feedstock using a Flow Blurring® multinebulizer in inductively coupled plasma-optical emission spectrometry

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    A simple and fast method for determining the content of Na, K, Ca, Mg, P, and 20 heavy metals in biodiesel samples with inductively coupled plasma optical emission spectrometry (ICP OES) using a two-nozzle Flow Blurring® multinebulizer prototype and on-line internal standard calibration, are proposed. The biodiesel samples were produced from different feedstock such as sunflower, corn, soybean and grape seed oils, via a base catalyst transesterification. The analysis was carried out without any sample pretreatment. The standards and samples were introduced through one of the multinebulizer nozzles, while the aqueous solution containing yttrium as an internal standard was introduced through the second nozzle. Thus, the spectral interferences were compensated and the formation of carbon deposits on the ICP torch was prevented. The determination coefficients (R2) were greater than 0.99 for the studied analytes, in the range 0.21–14.75 mg kg−1. Short-term and long-term precisions were estimated as relative standard deviation. These were acceptable, their values being lower than 10%. The LOQ for major components such as Ca, K, Mg, Na, and P, were within a range between 4.9 ng g−1 for Mg (279.553 nm) and 531.1 ng g−1 for Na (588.995 nm), and for the other 20 minor components they were within a range between 1.1 ng g−1 for Ba (455.403 nm) and 2913.9 ng g−1 for Pb (220.353 nm). Recovery values ranged between 95% and 106%.The authors gratefully acknowledge Universidad Nacional del Sur (UNS) and Instituto de Química del Sur – Universidad Nacional del Sur – Consejo Nacional de Investigaciones Científicas y Técnicas (INQUISUR-UNS-CONICET) from Argentina for the financial support. FDAO acknowledges Universidad de Alicante (UA) for his short visit fellowship. Ministerio de Asuntos Exteriores y de Cooperación (MAEC) and Dirección de Relaciones Culturales y Científicas (AECID) from Spain for the financial support. The authors wish to thank the Spanish Government (CTQ2011-23968) for the financial support

    Reversed-phase dispersive liquid–liquid microextraction for elemental analysis of gasoline by inductively coupled plasma optical emission spectrometry

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    In this work a green and fast sample preparation method based on reversed-phase dispersive liquid–liquid microextraction (RP-DLLME) was developed for the separation and preconcentration of several elements (i.e., Ag, As, Ba, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, S, Se, Sn and V) in gasoline samples before determination by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The extraction procedure was carried out in a reverse mode, since a small volume of the aqueous phase (i.e., 8 M HCl) is used to extract a relatively high volume of the organic phase (i.e., gasoline sample). Unlike conventional DLLME, in RP-DLLME the analytes were extracted from the organic phase into the aqueous phase. The experimental conditions for the microextraction procedure were: 5 g of sample, 8 M HCl as the extractant phase, mechanical agitation by vortex as the dispersion system, 115 μL of extractant volume, and 2 min extraction and 5 min centrifugation time. Under optimized extraction conditions the enrichment factor ranged between 3 and 53, and the limits of detection ranged between 0.02 and 50 μg kg−1. The proposed analytical method was validated and successfully used to analyze three gasoline samples. All gasoline samples were spiked at 100 μg kg−1 for all analytes, except sulfur (in this case at 1000 μg kg−1), obtaining recovery and RSD values within the range of 88–109% and 2–9%, respectively.The authors would like to thank the Regional Government of Valencia (Spain) (PROMETEO/2018/087) for the financial support, Agilent Technologies Inc. for the loan of the ICP-OES spectrometer, and Ingeniatrics for the OneNeb® provided. Financial support from Universidad Nacional del Sur is gratefully acknowledged. A. S. Lorenzetti, E. Vidal and C. E. Domini wish to thank Consejo Nacional de Investigaciones Científicas y Técnicas for the financial support received. The authors extend their appreciation to the Ministry of Science, Innovation and Universities for granting the Spanish Network of Excellence in Sample Preparation (RED2018-102522-T). This article is based upon work from the Sample Preparation Study Group and Network, supported by the Division of Analytical Chemistry of the European Chemical Society

    Mobile Databases: a Selection of Open Issues and Research Directions

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    International audienceThis paper reports on the main results of a specific action on mobile databases conducted by CNRS in France from October 2001 to December 2002. The objective of this action was to review the state of progress in mobile databases and identify major research directions for the French database community. Rather than provide a survey of all important issues in mobile databases, this paper gives an outline of the directions in which the action participants are now engaged, namely: copy synchronization in disconnected computing, mobile transactions, database embedded in ultra-light devices, data confidentiality, P2P dissemination models and middleware adaptability

    Low intrinsic efficacy for G protein activation can explain the improved side-effect profile of new opioid agonists

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    Biased agonism at G protein–coupled receptors describes the phenomenon whereby some drugs can activate some downstream signaling activities to the relative exclusion of others. Descriptions of biased agonism focusing on the differential engagement of G proteins versus β-arrestins are commonly limited by the small response windows obtained in pathways that are not amplified or are less effectively coupled to receptor engagement, such as β-arrestin recruitment. At the μ-opioid receptor (MOR), G protein–biased ligands have been proposed to induce less constipation and respiratory depressant side effects than opioids commonly used to treat pain. However, it is unclear whether these improved safety profiles are due to a reduction in β-arrestin–mediated signaling or, alternatively, to their low intrinsic efficacy in all signaling pathways. Here, we systematically evaluated the most recent and promising MOR-biased ligands and assessed their pharmacological profile against existing opioid analgesics in assays not confounded by limited signal windows. We found that oliceridine, PZM21, and SR-17018 had low intrinsic efficacy. We also demonstrated a strong correlation between measures of efficacy for receptor activation, G protein coupling, and β-arrestin recruitment for all tested ligands. By measuring the antinociceptive and respiratory depressant effects of these ligands, we showed that the low intrinsic efficacy of opioid ligands can explain an improved side effect profile. Our results suggest a possible alternative mechanism underlying the improved therapeutic windows described for new opioid ligands, which should be taken into account for future descriptions of ligand action at this important therapeutic target

    Disease-specific phenotypes in dopamine neurons from human iPS-based models of genetic and sporadic Parkinson's disease

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    Induced pluripotent stem cells (iPSC) offer an unprecedented opportunity to model human disease in relevant cell types, but it is unclear whether they could successfully model age-related diseases such as Parkinson's disease (PD). Here, we generated iPSC lines from seven patients with idiopathic PD (ID-PD), four patients with familial PD associated to the G2019S mutation in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene (LRRK2-PD) and four age- and sex-matched healthy individuals (Ctrl). Over long-time culture, dopaminergic neurons (DAn) differentiated from either ID-PD- or LRRK2-PD-iPSC showed morphological alterations, including reduced numbers of neurites and neurite arborization, as well as accumulation of autophagic vacuoles, which were not evident in DAn differentiated from Ctrl-iPSC. Further induction of autophagy and/or inhibition of lysosomal proteolysis greatly exacerbated the DAn morphological alterations, indicating autophagic compromise in DAn from ID-PD- and LRRK2-PD-iPSC, which we demonstrate occurs at the level of autophagosome clearance. Our study provides an iPSC-based in vitro model that captures the patients' genetic complexity and allows investigation of the pathogenesis of both sporadic and familial PD cases in a disease-relevant cell type

    Mobilité et bases de données : Etat de l'art et perspectives: 1ère partie. Action spécifique CNRS « Mobilité/Accès aux données »

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    National audienceThis paper is the result of the collective work done within the CNRS specific action Mobility/Data access with seven french laboratories IMAG-LSR, INT-Evry, LIP6, LORIA, PRiSM, EPFL, LIRMM . All pursuiving research in mobile computing and mobile databases. The action started in October 2001 for an initial period of one year. The activities and results of this action are available online at [AS_BDMobile]. The objective of this paper is to review the state of progress in mobile databases and identify major research directions. However, the research domain is so broad that we cannot pretend to be exhaustive. First, we propose a classification of mobile applications and a characterization of their execution environments. Then, we analyze the following issues: management of localization data, data access models, copy consistency and synchronization, management of embedded data, data confidentiality, and adaptability of software infrastructures to mobility and disconnection. For editorial reasons, this paper is published as a chronicle with two parts of equal importance.Ce document est le résultat d'un travail collectif réalisé par les membres de l'action spécifique CNRS « Mobilité/Accès aux données ». Il fait le point sur l'état d'avancement des travaux réalisés dans le domaine des bases de données mobiles et identifie quelques orientations de recherche jugées particulièrement pertinentes. Compte tenu de la largeur du domaine, ce document ne prétend cependant pas à l'exhaustivité. Après une classification des applications mobiles et une caractérisation de leur environnement d'exécution, les problématiques suivantes sont analysées : gestion des données de localisation, modèles d'accès aux données, cohérence des traitements et synchronisation de copies, gestion de données embarquées, confidentialité des données et enfin adaptabilité des infrastructures logicielles à la mobilité et à la déconnexion
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