875 research outputs found

    PHYTOCHEMICAL SCREENING, FREE RADICAL SCAVENGING AND ANTI-INFLAMMATORY ACTIVITY OF CROTON LEPTOSTACHYUS KUNTH LEAF EXTRACTS.

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    Objective: To study the biological potential of Croton leptostachyus Kunth (Mosquero) leaves through phytochemical screening and determination of the free radical scavenging capacity (against DPPH. and ABTS.+) and anti-inflammatory activity via a TPA induced auricular edema model in ICR mice of the crude ethanolic extract and subextracts (of n-hexane, ethyl acetate and ethanol).Materials and methods: The C. lepstostachyus leaf extracts were obtained via ethanolic maceration and subsequent partition of the dry ethanolic crude extract with n-hexane and ethyl acetate, the aforementioned samples were tested for phytochemical composition, antiradical activity (DPPH. and ABTS.+), and anti-inflammatory activity (TPA induced auricular edema model in mice).Results: The phytochemical plant profile showed a diversity of secondary metabolites such as terpenic compounds (triterpenes and saponins), phenolics (flavonoids, tannins and phenylpropanoids), alkaloids and a minor proportion of iridoids and coumarins. Free radical scavenging assays indicated a presumable combined effect of the C. leptostachyus leaf metabolites considering the fact that the crude extract was the most active scavenger of DPPH. and ABTS.+. However, between the subextracts, the ethanolic subextract showed the highest antiradical activity, indicating a presumable major contribution of phenolic compounds in this result. The topical anti-inflammatory action of ethyl acetate subextract showed a possible enhanced effect due to a higher concentration of medium polarity compounds;  no anti-inflammatory activity of the subsequent fractions of this sample was observed,  indicating  a probably interaction of the metabolites contained therein.Conclusion: C. leptostachyus leaf extracts showed potential as free radical scavengers and anti-inflammatory compounds sources.Keywords: Croton leptostachyus, Free radical scavenging activity, Anti-inflammatory activity

    Variabilidad genética de Aedes aegypti en el departamento de Sucre, Colombia, mediante el análisis de la secuencia de nucleótidos del gen mitocondrial ND4

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    Introduction. Aedes aegypti is the most important mosquito species in America for the transmission of viruses of dengue, Zika, Chikungunya and yellow fever. Ecological factors as well as chemical controls can affect the genetic composition of Ae. aegypti populations, which is why its genetic characterization is necessary.Objective. To determine the genetic variability of Ae. aegypti populations in four municipalities of Sucre department, Colombia.Materials and methods. Larvae of Ae. aegypti, collected in the municipalities of Sincelejo, Sampués, Corozal and Guaranda, Sucre department, were reared under laboratory conditions to adult stage. A segment of the mitochondrial ND4 gene which codes for the subunit 4 of the enzyme NADH-dehydrogenase was used as genetic marker. The genetic analysis included the estimation of parameters of nucleotide and haplotype diversity, genetic structure and gene flow.Results. One hundred and eight partial sequences of 357 nucleotides and four nucleotide haplotypes of the ND4 gene of Ae. aegypti were obtained. A significantly high genetic differentiation was found between the Sampués and Guaranda populations (FST=0.59467), Sincelejo and Sampués (FST=0.25637), and Corozal and Guaranda (FST=0.22237). A high gene flow (Nm=infinite) was observed among the populations of Sincelejo and Corozal.Conclusion. There are genetic differences between the Ae. aegypti populations from the municipalities of Sucre department. The presence of a new haplotype of the mitochondrial ND4 gene of Ae. aegypti in Colombia was recorded, detected in the municipality of Sincelejo.Introducción. Aedes aegypti es la especie de mosquito de mayor relevancia en América por transmitir los virus del dengue, del Zika, del chikungunya y de la fiebre amarilla. Tanto factores ecológicos como el control químico, pueden influir en la composición genética de las poblaciones de Ae. aegypti, por lo cual es necesaria su caracterización.Objetivo. Determinar la variabilidad genética de las poblaciones de Ae. aegypti en cuatro municipios del departamento de Sucre, Colombia.Materiales y métodos. Larvas de Ae. aegypti, recolectadas en los municipios de Sincelejo, Sampués, Corozal y Guaranda del departamento de Sucre, fueron criadas en laboratorio hasta el estado adulto. Como marcador genético, se utilizó un segmento del gen mitocondrial ND4, que codifica para la subunidad 4 de la enzima NADH-deshidrogenasa. El análisis genético incluyó la estimación de parámetros de diversidad de nucleótidos, haplotipos, de estructura genética y de flujo de genes.Resultados. Se obtuvieron 108 secuencias parciales de 357 nucleótidos y cuatro haplotipos de nucleótidos del gen ND4 de Ae. aegypti. Se encontró una diferenciación genética significativamente alta entre las poblaciones de Sampués y Guaranda mediante el índice de fijación (FST=0,59467), las de Sincelejo y Sampués (FST= 0,25637), y las de Corozal y Guaranda (FST= 0,22237). Se evidenció un gran flujo de genes (Nm=infinito) entre las poblaciones de Sincelejo y Corozal.Conclusión. Existen diferencias genéticas entre las poblaciones del mosquito Ae. aegypti de los municipios del departamento de Sucre. Se registra la presencia de un nuevo haplotipo del gen mitocondrial ND4 de Ae. aegypti en Colombia, el cual fue detectado en el municipio de Sincelejo

    Primer reporte de la mutación F1534C asociada con resistencia cruzada a DDT y piretroides en Aedes aegypti en Colombia

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    Introduction: The main strategy for the control of Aedes aegypti, vector of dengue, chikungunya and Zika viruses, is based on the use of insecticides to reduce its populations. However, their use has led to insect resistance to these chemicals. Objective: To determine the presence of the F1534C mutation associated with cross-resistance to DDT and pyrethroids in A. aegypti in Sincelejo, Colombia. Materials and methods: We studied nine specimens of A. aegypti that showed resistance to lambdacyhalothrin in bioassays developed by the Secretaría de Salud de Sucre. We used a semi-nested PCR as previously described by Harris, et al., to amplify exon 31 of the para gene of the voltage-dependent sodium channel of A. aegypti. We sequenced, edited, and analyzed PCR products with the MEGA 5 software. Results: We detected the wild and mutant alleles of exon 31 in all of the nine mosquitoes tested, and observed the substitution of thymine for guanine in the nucleotide sequence of the mutant allele, producing a change to UGC in the UUC codon, which led to the replacement of phenylalanine by cysteine in residue 1534 of the protein. Conclusion: The nine mosquitoes analyzed presented a heterozygote genotype for the F1534C mutation, whose phenotypic effect is knockdown resistance (kdr) to DDT and pyrethroids.Introducción. La principal estrategia para el control de Aedes aegypti, vector de los virus del dengue, del chikungunya y del zika, se basa en la utilización de insecticidas con el fin de disminuir su población. Sin embargo, su uso ha implicado que el insecto desarrolle resistencia a estos agentes químicos. Objetivo. Determinar la presencia de la mutación F1534C asociada con resistencia cruzada al DDT y los piretroides en mosquitos de la especie A. aegypti en Sincelejo, Colombia. Materiales y métodos. El estudio se desarrolló con nueve ejemplares de A. aegypti que mostraron resistencia a lambdacialotrina en bioensayos desarrollados por la Secretaría de Salud de Sucre. Se utilizó una reacción en cadena de la polimerasa (PCR) semianidada siguiendo la metodología descrita por Harris, et al., para amplificar el exón 31 del gen para del canal de sodio dependiente de voltaje de A. aegypti. Los productos de la PCR se secuenciaron, editaron y analizaron con el programa MEGA 5. Resultados. En todos los mosquitos evaluados se detectó la presencia del alelo silvestre y mutante del exón 31. En la secuencia de nucleótidos del alelo mutante, se observó la sustitución de timina por guanina, la cual produce el cambio del codón UUC por UGC y conlleva el reemplazo del aminoácido fenilalanina por cisteína en el residuo 1534 de la proteína. Conclusión. Los nueve mosquitos analizados presentaron un genotipo heterocigoto para la mutación F1534C, cuyo efecto fenotípico es la resistencia al “derribo” (knock-down resistance, kdr) con DDT y piretroides

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

    Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

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    Reconstruction of signal amplitudes in the CMS electromagnetic calorimeter in the presence of overlapping proton-proton interactions

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    A template fitting technique for reconstructing the amplitude of signals produced by the lead tungstate crystals of the CMS electromagnetic calorimeter is described. This novel approach is designed to suppress the contribution to the signal of the increased number of out-of-time interactions per beam crossing following the reduction of the accelerator bunch spacing from 50 to 25 ns at the start of Run 2 of the LHC. Execution of the algorithm is sufficiently fast for it to be employed in the CMS high-level trigger. It is also used in the offline event reconstruction. Results obtained from simulations and from Run 2 collision data (2015-2018) demonstrate a substantial improvement in the energy resolution of the calorimeter over a range of energies extending from a few GeV to several tens of GeV.Peer reviewe

    Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

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    The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported

    Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

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    A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.Peer reviewe

    Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at √s = 13 TeV

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    A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS collaboration at the LHC, using a data set corresponding to an integrated luminosity of 130 fb−1, recorded at a center-of-mass energy of 13 TeV in 2016–2018. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for production via vector boson fusion and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, the observed (expected) 95% confidence level upper limit on the branching fraction is 3.5 (2.8)%. This is the first search for such decays in the vector boson fusion channel. Combination with a previous search for Higgs bosons produced in association with a Z boson results in an observed (expected) upper limit on the branching fraction of 2.9 (2.1)% at 95% confidence level
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