1,700 research outputs found

    The decays h+- -> W-+ h0(a0) within an extension of the MSSM with one complex Higgs triplet

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    The vertex H+-W-+h0, involving the gauge bosons W-+, the charged (H+-) and the lightest neutral (h0) Higgs bosons, arises within the context of many extensions of the SM, and it can be used to probe the Higgs sector of such extensions via the decay H+- -> W+- h0. We discuss the strength of this vertex for an extension of the MSSM with an additional complex Higgs triplet. By using this model, we find regions of the parameter space where the decay H+- -> W+- h0 is not only kinematically allowed, but it also becomes an important decay mode and in some cases the dominant one.Comment: 10 figure

    Use of quadrupole time-of-flight mass spectrometry for proposal of transformation products of the herbicide bromacil after water chlorination

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    The herbicide bromacil has been extensively used in the Spanish Mediterranean region, and although plant protection products containing bromacil have been withdrawn by the European Union, this compound is still frequently detected in surface and ground water of this area. However, the fast and complete disappearance of this compound has been observed in water intended for human consumption, after it has been subjected to chlorination. There is a concern about the possible degradation products formed, since they might be present in drinking water and might be hazardous. In this work, the sensitive full-spectrum acquisition, high resolution and exact mass capabilities of hybrid quadrupole time-of-flight (QTOF) mass spectrometry have allowed the discovery and proposal of structures of transformation products (TPs) of bromacil in water subjected to chlorination. Different ground water samples spiked at 0.5 µg/mL were subjected to the conventional chlorination procedure applied to drinking waters, sampling 2-mL aliquots at different time intervals (1, 10 and 30 min). The corresponding non-spiked water was used as control sample in each experiment. Afterwards, 50 μL of the water was directly injected into an ultra-high-pressure liquid chromatography (UHPLC)/electrospray ionization (ESI)-(Q)TOF system. The QTOF instrument enabled the simultaneous recording of two acquisition functions at different collision energies (MSE approach): the low-energy (LE) function, fixed at 4 eV, and the high-energy (HE) function, with a collision energy ramp from 15 to 40 eV. This approach enables the simultaneous acquisition of both parent (deprotonated and protonated molecules) and fragment ions in a single injection. The low mass errors observed for the deprotonated and protonated molecules (detected in LE function) allowed the assignment of a highly probable molecular formula. Fragment ions and neutral losses were investigated in both LE and HE spectra to elucidate the structures of the TPs found. For those compounds that displayed poor fragmentation, product ion scan (MS/MS) experiments were also performed. On processing the data with specialized software (MetaboLynx), four bromacil TPs were detected and their structures were elucidated. To our knowledge, two of them had not previously been reported

    Estimation of illicit drug use in the main cities of Colombia by means of urban wastewater analysis

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    Wastewater-based epidemiology (WBE) relies on the principle that traces of compounds, which a population is exposed to or consume, are excreted unchanged or as metabolites in urine and/or feces, and ultimately end up in the sewer network. Measuring target metabolic residues i.e. biomarkers in raw urban wastewater allows identifying the exposure or use of substances of interest in a community. Up to date, the most popular application of WBE is the estimation of illicit drug use and studies have been made mainly across Europe, which has allowed estimating and comparing drug use in many European cities. However, until now a comprehensive study applying WBE on the most frequently consumed illicit drugs has not been performed in South American countries. In this work, we applied this approach to samples from Colombia, selecting two of the most populated cities: Bogotá and Medellin. Several biomarkers were selected to estimate drug use of cocaine, cannabis, amphetamine, methamphetamine, MDMA (ecstasy), heroin and ketamine. Composite samples (24-h) were collected at the corresponding municipal wastewater treatment plants. Sample treatment was performed at location by applying solid-phase extraction (SPE). Before SPE, the samples were spiked with appropriate isotope labeled internal standards. In parallel, samples (spiked with the analytes under study at two concentration levels) were also processed for quality control. Analysis of influent wastewater was made by liquid chromatography-tandem mass spectrometry, with triple quadrupole analyzer. Data shown in this paper reveal a high use of cocaine by the population of the selected Colombian cities, particularly from Medellin, while the use of other illicit drugs were low. The relevance of using quality control samples, particularly in collaborative studies, as those presented in this work, where research groups from different countries participate and where the samples had to be shipped overseas, is highlighted in this paper.The authors of University Jaume I acknowledge the financial support of Generalitat Valenciana (Prometeo II 2014/023) and of the Spanish Ministry of Economy and Competitiveness (Project ref. CTQ2015-65603). Dr. Lubertus Bijlsma acknowledges NPS-Euronet (HOME/2014/JDRUG/AG/DRUG/7086), co-funded by the European Union, for his post-doctoral fellowship. This publication reflects the views only of the authors, and the European Commission cannot be held responsible for any use which may be made of the information contained therein

    Quinones Facilitate the Self-Assembly of the Phosphorylated Tubulin Binding Region of Tau into Fibrillar Polymers.

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    The fragment of tau containing the first and third tubulin-binding motifs, involved in self- assembly of tau, was phosphorylated by protein kinase A (PKA). In the presence of hydroxynonenal (HNE) or in the presence of quinones such as juglone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone (coenzyme Q0 or DMM), or menadione, the polymerization of this phosphorylated tau fragment is catalyzed, whereas polymerization of the unmodified fragment takes place in a lesser extent. The quinones coenzyme Q0 and menadione are found in every cell, including neural cells, and may interact with tau protein to facilitate its assembly into filamentous structures. These tau filaments, assembled in the presence of quinones, have a fibrillar morphology very similar to that of paired helical filaments present in the brains of patients with Alzheimer’s disease.pre-print862 K

    Recent developments from the loop-tree duality

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    In this talk, we review the most recent developments of the four-dimensional unsubstraction (FDU) and loop-tree duality (LTD) methods. In particular, we make emphasis on the advantages of the LTD formalism regarding asymptotic expansions of loop integrands.Comment: 8 pages, 1 figure. Presented at 13th International Symposium on Radiative Corrections RADCOR2017, 24-29 September 2017, St. Gilgen, Austri

    Analytical strategy to investigate 3,4-methylenedioxypyrovalerone (MDPV) metabolites in consumers’ urine by high-resolution mass spectrometry

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    The potential of high-resolution mass spectrometry (HRMS) for the investigation of human in vivo metabolism of 3,4-methylenedioxypyrovalerone (MDPV) using urine collected from a consumer (this is, in non-controlled experiments) has been investigated. As a control sample was not available, the common approach based on the comparison of a control/blank sample and samples collected after drug intake could not be used. Alternatively, an investigation based on common fragmentation pathways was applied, assuming that most metabolites share some fragments with the parent drug. An extension of this approach was also applied based on the fragmentation pathway of those metabolites identified in urine samples in the first step. The use of MSE experiments (sequential acquisition of mass spectra at low and high collision energy) has been crucial to this aim as it allowed promoting fragmentation in the collision cell without any previous precursor ion selection. MDPV belongs to the group of new psychoactive substances (NPS), being known as the “cannibal drug”. This substance is being abused more and more and is associated with dangerous side effects. The human metabolites (both phase I and phase II) were detected and tentatively identified by accurate mass full-spectrum measurements using ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Following this strategy, up to 10 phase I metabolites, together with some glucuronides and sulphates, were detected and tentative structures were proposed. Several compounds identified in this work have not been previously reported in the literature.MINECO (CTQ2012-36189) i Generalitat Valenciana (research group of excellence PROMETEOII/2014/023; ISIC Envi-Food 2014/016). Spanish Health National System is acknowledged for O. J. Pozo contract (MS10/00576)

    Pesticide residues and transformation products in groundwater from a Spanish agricultural region on the Mediterranean Coast

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    An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TP
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