5,976 research outputs found

    A new species of Daldinia (Xylariaceae) from the Argentine subtropical montane forest

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    Based on a combination of morphological, molecular phylogenetic and chemotaxonomic evidence, a new species of Daldinia from Northwest of Argentina is described. Daldinia korfii is morphologically related to D. placentiformis, but differs in having brown vinaceous, KOH-extractable pigments and the tissue below the perithecial layer is composed of inconspicuous to conspicuous alternating zones in the new taxon.Fil: Sir, Esteban Benjamin. Fundación Miguel Lillo. Dirección de Botánica. Instituto de Micologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lambert, C.. Helmholtz-Zentrum für Infektionsforschung; AlemaniaFil: Wendt, L.. Helmholtz-Zentrum für Infektionsforschung; AlemaniaFil: Hladki, Adriana Ines. Fundación Miguel Lillo. Dirección de Botánica. Instituto de Micologia; ArgentinaFil: Romero, Andrea Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Stadler, M.. Helmholtz-Zentrum für Infektionsforschung; Alemani

    Elachistocleis haroi Pereyra, Akmentins, Laufer & Vaira, 2013 (Anura: Microhylidae) en Paraguay

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    Elachistocleis haroi (Anura: Microhylidae) fue descrita de las Provincias de Jujuy, Salta y Formosa en Argentina y el departamento Tarija en Bolivia. Sobre la base de ejemplares albergados en el Museo Nacional de Historia Natural del Paraguay y Colección Zoológica de la Facultad de Ciencias Exactas y Naturales, extendemos la distribución conocida de la especie a los departamentos de Alto Paraguay, Boquerón y Presidente Hayes, en la Región Occidental de Paraguay.Elachistocleis haroi (Anura: Microhylidae) was described from the provinces of Jujuy, Salta and Formosa in Argentina and the Tarija department in Bolivia. Based on specimens housed in the Museo Nacional de Historia Natural del Paraguay and Colección Zoológica de la Facultad de Ciencias Exactas y Naturales, we extend the range of the species to the departments of Alto Paraguay, Boquerón and Presidente Hayes, in western Paraguay.Fil: Caballero Gini, Andrea. Universidad Nacional de Asuncion; ParaguayFil: Bueno Villafañe, Diego. Universidad Nacional de Asuncion; Paraguay. Museo Nacional de Historia Natural del Paraguay; ParaguayFil: Romero Nardelli, L.. Universidad Nacional de Asuncion; ParaguayFil: Lavilla, Esteban Orlando. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentin

    Conversion of 3-amino-4-arylamino-1H-isochromen-1-ones to 1-arylisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones : synthesis, spectroscopic characterization and the structures of four products and one ring-opened derivative

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    The authors thank 'Centro de Instrumentación Científico-Técnica of Universidad de Jaén' for data collection. The authors thank Universidad de Ciencias Aplicadas y Ambientales (UDCA), Universidad Nacional de Colombia, the Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain) and the Universidad de Jaén for financial support.An efficient synthesis of 1-aryl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazo­tization of 3-amino-4-aryl­amino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The mol­ecules of 1-phenyl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methyl­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the mol­ecules into simple chains, which are further linked into sheets by π-stacking inter­actions in (II) but not in (III). In the structure of 1-(4-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. When com­pound (II) was exposed to a strong acid in methanol, qu­anti­tative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hy­droxy-1-(2-methyl­phen­yl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the mol­ecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.Publisher PDFPeer reviewe

    Spectrophotometric determination of the deltamethrin

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    In the province of Corrientes is found highest production of indoor plants from all Argentina, specially in the northeast of this province. This is because the low frequency orthelack of frosts, allowing a lower cost in the production, since heating is not needed. In this type of cultive is commonly used thedeltamethrin, as the result of this, the validation of a simple method comparable with the gas chromatography for the determination of this Pesticide on both, irrigation and consumption water, was studied. In this work, a spectrophotometric method is proposed for the determination of deltamethrin inirrigation water from the area of flower crops located in the Department of Concepción in the province of Corrientes. Deltamethrin solutions in a range from 0,025 to 1 mg/L on irrigation water were prepared. The absorbance spectrum was scanned between 200 and 400 nm. The maximum absorbance was found at 220 nm. A calibration curve in the range from 0.025 to 1 mg/L, responded to A = (0.3246± 0.0224) C + (0.0096 ± 0.0068) with R2 = 0.998. The % RSD was 0.961 indicating good repeatability for the analytical procedure. The accuracy in the recovery experience was 99.0 - 109.6%. The statistical comparison using the t-test and the F-test indicates that there are no significant differences between GC and spectrophotometric methods, with a confidence level of 95%. The specificity and intermediate accuracy tests were satisfactory.Fil: Gimenez, L. I.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Michellod, A. M. M.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Jorge, M. J.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Pila, Andrea Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; ArgentinaFil: Bordón, Alexander Germán. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Profeta, Mariela Inés. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Romero, Jorge Marcelo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Jorge, Nelly Lidia. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; Argentin

    Engineering a robust cyclohexanone monooxygenase for the production of methyl propanoate

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    Cyclohexanone monooxygenase (EC 1.14.13.22) from Acinetobacter calcoaceticus (AcCHMO) catalyzes the Baeyer-Villiger oxidation of 2-butanone, producing both ethyl acetate and methyl propanoate (Fig. 1A).[1] Methyl propanoate is of industrial interest as a precursor of acrylic plastic. We have replaced various residues near the substrate and NADP+ binding sites in AcCHMO using saturation mutagenesis with the aim of increasing both the activity on 2-butanone and the methyl propanoate/total product ratio. Whole cell biotransformations were prepared for the resulting libraries and the analyses were carried out by headspace GC analysis. A higher conversion yield (92%) and kcat value (0.5 s-1) than wild type AcCHMO (52% and 0.3 s-1, respectively) were observed for T56S AcCHMO. I491A AcCHMO exhibited a significant improvement over the wild type enzyme in the desired regioselectivity using 2-butanone as a substrate (40% vs. 26% methyl propanoate, respectively). The T56S/I491A double mutant combined the beneficial effects of both mutations (Fig. 1B).[2] Recently, we reported on the discovery, characterization, and crystal structure determination of a CHMO from Thermocrispum municipale (TmCHMO).[3] A Ser residue was found in TmCHMO at the equivalent position to that of AcCHMO T56. The TmCHMO I493, equivalent to AcCHMO I491, was replaced with an Ala by site-directed mutagenesis. The resulting mutant exhibited a similar activity and regioselectivity to those observed for T56S/I491A AcCHMO using the substrate 2-butanone. This study shows that even for a relatively small aliphatic substrate, regioselectivity can be tuned by structure-inspired enzyme engineering in two different CHMOs. Beneficial mutations previously carried out for AcCHMO, or other CHMOs, may be repeated in TmCHMO achieving similar effects. This is very attractive for biocatalysis since TmCHMO is significantly more thermostable and solvent tolerant than all CHMOs described so far. .Please click Additional Files below to see the full abstract

    Molecules, dust, and protostars in NGC 3503

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    Aims. We present here a follow-up study of the molecular gas and dust in the environs of the star forming region NGC 3503. This study aims at dealing with the interaction of the HII region NGC 3503 with its parental molecular cloud, and also with the star formation in the region, that was possibly triggered by the expansion of the ionization front against the parental cloud. Methods. To analyze the molecular gas we use CO(J = 2 → 1), 13CO(J = 2 → 1), C18O(J = 2 → 1), and HCN(J = 3 → 2) line data obtained with the on-the-fly technique from the APEX telescope. To study the distribution of the dust, we make use of unpublished images at 870 μm from the ATLASGAL survey and IRAC-GLIMPSE archival images. We use public 2MASS and WISE data to search for infrared candidate young stellar objects (YSOs) in the region. Results. The new APEX observations allowed the substructure of the molecular gas in the velocity range from ~-28 km s-1 to -23 km s-1 to be imaged in detail. The morphology of the molecular gas close to the nebula, the location of the PDR, and the shape of radio continuum emission suggest that the ionized gas is expanding against its parental cloud, and confirm the champagne flow scenario. We have identified several molecular clumps and determined some of their physical and dynamical properties such as density, excitation temperature, mass, and line width. Clumps adjacent to the ionization front are expected to be affected by the HII region, unlike those that are distant from it. We have compared the physical properties of the two kinds of clumps to investigate how the molecular gas has been affected by the HII region. Clumps adjacent to the ionization fronts of NGC 3503 and/or the bright rimmed cloud SFO 62 have been heated and compressed by the ionized gas, but their line width is not different from those that are too distant from the ionization fronts. We identified several candidate YSOs in the region. Their spatial distribution suggests that stellar formation might have been boosted by the expansion of the nebula. We discard the collect-and-collapse scenario and propose alternative mechanisms such as radiatively driven implosion on pre-existing molecular clumps or small-scale Jeans gravitational instabilities.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

    Tabaquismo: un problema que afecta a los jóvenes universitarios a nivel nacional e internacional: Tobacco: A problem that affects young universities at the national and international levels

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    The World Health Organization defines smoking as a chronic addictive disease widespread worldwide. It represents one of the greatest threats to public health, affecting children, youth and adults. It is estimated, that there are 1.300 million smokers in the world and about 80% of these live in countries where there is a high rate of morbidity and mortality associated with tobacco mainly in adult consumers. In particular, the consumption of tobacco among young university students is evident and worrisome. Different authors in the world have raised factors for tobacco use among adolescents and young adults. Such studies argue that the habit of smoking usually begins during adolescence and consolidates in the university stage. Smoking in parents, relatives, and friends is a factor, perhaps the most remarkable, which is associated with the acquisition of smoking as a habit.La Organización Mundial de la Salud define al tabaquismo como una enfermedad adictiva crónica muy extendida a nivel mundial. Representa una de las mayores amenazas para la salud púbica, afectando a niños, jóvenes y adultos. Se calcula que existen 1.300 millones de fumadores en el mundo y alrededor del 80% de estos viven en países en los que existe una alta tasa de morbilidad y mortalidad asociada al tabaco principalmente en consumidores adultos. De manera particular, el consumo de tabaco ente jóvenes universitarios es evidente y preocupante. Diferentes autores en el mundo han planteado factores para el consumo de tabaco entre adolescentes y adultos jóvenes. Tales estudios sostienen que el hábito de fumar inicia, por lo general, durante la adolescencia y se consolida en la etapa universitaria. Además, el tabaquismo en progenitores, familiares y amigos es un factor, quizás el más destacable, que se asocia a la adquisición del hábito tabáquico

    Factores asociados al consumo de tabaco en estudiantes universitarios de Lima metropolitana.: Factors associated with tobacco consumption in university students of Lima metropolitan

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    Introduction: The consumption of tobacco is very harmful to people’s health. According to WHO, smoking is the cause of death of 8 million people a year. Objetive: The purpose of the research was to determine the factors associated with the consumption of tobacco in university students in Metropolitan Lima. Methods: The sample consisted of 447 students from Lima universities, the survey was applied: Fagerstrom test. Subsequently the data was analyzed using tables of: distribution, frequency, contingency.  Results: It was evidenced through the X2 statistical test that there is a significant association between the variables sex and smoking habit, OR = 1.93, IC 95%[1.29-6,519]. It was also observed that having smoking parents is significantly associated with the habit of smoking by the children, with a value p =0,000 of X2 and the OR 3.31, IC 95%[2,145 - 5,116]. Conclusion: The variables sex and parental background have a significant association with tobacco consumption, emphasizing that our family environment deserves to be safe, healthy and free of tobacco smokeIntroducción: El consumo de tabaco es muy perjudicial para la salud de las personas, según la OMS el tabaquismo es la causa de muerte de 8 millones de personas al año. Objetivo: El propósito de la investigación fue determinar los factores asociados al consumo de tabaco en estudiantes universitarios de Lima Metropolitana. Métodos: La muestra estuvo conformada por 447 estudiantes de universidades de Lima, se aplicó la encuesta: Test de Fagerstrom. Los datos fueron analizados utilizando tablas de distribución, frecuencia, y contingencia. Resultados: Se evidenció a través de la prueba estadística X2 que existe asociación significativa entre las variables sexo y el hábito de fumar, OR = 1.93, IC 95% [1.29 – 6,519].  También se pudo observar que tener padres fumadores está asociado significativamente al hábito de fumar por parte de los hijos, con un valor de p=0,000 del X2 y el OR 3,31, IC 95% [2,145 – 5,116].  Conclusión: Las variables sexo masculino y antecedentes parentales tienen asociación significativa con el consumo de tabaco enfatizando que nuestro entorno familiar merece ser seguro, saludable y libre del humo de tabaco

    Molecules, dust, and protostars in NGC 3503

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    Aims. We present here a follow-up study of the molecular gas and dust in the environs of the star forming region NGC 3503. This study aims at dealing with the interaction of the HII region NGC 3503 with its parental molecular cloud, and also with the star formation in the region, that was possibly triggered by the expansion of the ionization front against the parental cloud. Methods. To analyze the molecular gas we use CO(J = 2 → 1), 13CO(J = 2 → 1), C18O(J = 2 → 1), and HCN(J = 3 → 2) line data obtained with the on-the-fly technique from the APEX telescope. To study the distribution of the dust, we make use of unpublished images at 870 μm from the ATLASGAL survey and IRAC-GLIMPSE archival images. We use public 2MASS and WISE data to search for infrared candidate young stellar objects (YSOs) in the region. Results. The new APEX observations allowed the substructure of the molecular gas in the velocity range from ~-28 km s-1 to -23 km s-1 to be imaged in detail. The morphology of the molecular gas close to the nebula, the location of the PDR, and the shape of radio continuum emission suggest that the ionized gas is expanding against its parental cloud, and confirm the champagne flow scenario. We have identified several molecular clumps and determined some of their physical and dynamical properties such as density, excitation temperature, mass, and line width. Clumps adjacent to the ionization front are expected to be affected by the HII region, unlike those that are distant from it. We have compared the physical properties of the two kinds of clumps to investigate how the molecular gas has been affected by the HII region. Clumps adjacent to the ionization fronts of NGC 3503 and/or the bright rimmed cloud SFO 62 have been heated and compressed by the ionized gas, but their line width is not different from those that are too distant from the ionization fronts. We identified several candidate YSOs in the region. Their spatial distribution suggests that stellar formation might have been boosted by the expansion of the nebula. We discard the collect-and-collapse scenario and propose alternative mechanisms such as radiatively driven implosion on pre-existing molecular clumps or small-scale Jeans gravitational instabilities.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

    Plasma ammonia levels predict hospitalisation with liver-related complications and mortality in clinically stable outpatients with cirrhosis

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    BACKGROUND AND AIMS: Hyperammonaemia is central in the pathogenesis of hepatic encephalopathy, but also has pleiotropic deleterious effects on several organ systems, impacting on immune function, sarcopenia, energy metabolism and portal hypertension. This study was performed to test the hypothesis that severity of hyperammonaemia is a risk factor for liver-related complications in clinically stable outpatients with cirrhosis. METHODS: We collected data from 754 clinically stable outpatients with cirrhosis from 3 independent liver units. Baseline ammonia levels were corrected to the upper limit of normal (AMM-ULN) for the reference laboratory. The primary endpoint was hospitalisation with liver-related complications (a composite endpoint of bacterial infection, variceal bleeding, overt hepatic encephalopathy, or new onset or worsening of ascites). Multivariable competing risk frailty analysis and fast unified random forest were performed to predict complications and mortality. External validation was carried out using prospective data from 130 cirrhotic patients in an independent tertiary liver centre. RESULTS: Overall, 260 (35%) patients were hospitalised with liver-related complications. On multivariable analysis, AMM-ULN was an independent predictor of both liver-related complications (HR=2.13; 95%CI=1.89-2.40; p<0.001) and mortality (HR=1.45; 95%CI=1.20-1.76; p<0.001). AUROC of AMM-ULN was 77.9% for 1-year complications, higher than traditional severity scores. Statistical differences in survival were found between high and low levels of AMM-ULN both for complications and mortality (p<0.001) using 1.4 as the optimal cut-off from the training set. AMM-ULN remained a key variable for the prediction of complications within the random forests model in the derivation cohort and upon external validation. CONCLUSION: Ammonia is an independent predictor of hospitalisation with liver-related complications and mortality in clinically stable outpatients with cirrhosis and performs better than traditional prognostic scores in predicting complications. LAY SUMMARY: We conducted a prospective cohort study evaluating the association of blood ammonia levels with the risk of adverse outcomes in 754 patients with stable cirrhosis across 3 independent liver units. We found that ammonia is a key determinant that helps to predict which patients will be hospitalised, develop liver-related complications and die; this was confirmed in an independent cohort of patients
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