On the relevance of polyynyl-substituted PAHs to astrophysics

We report on the absorption spectra of the polycyclic aromatic hydrocarbon (PAH) molecules anthracene, phenanthrene, and pyrene carrying either an ethynyl (-C2H) or a butadiynyl (-C4H) group. Measurements were carried out in the mid infrared at room temperature on grains embedded in CsI pellets and in the near ultraviolet at cryogenic temperature on molecules isolated in Ne matrices. The infrared measurements show that interstellar populations of polyynyl-substituted PAHs would give rise to collective features in the same way non-substituted PAHs give rise to the aromatic infrared bands. The main features characteristic of the substituted molecules correspond to the acetylenic CH stretching mode near 3.05 mum and to the almost isoenergetic acetylenic CCH in- and out-of-plane bending modes near 15.9 mum. Sub-populations defined by the length of the polyynyl side group cause collective features which correspond to the various acetylenic CC stretching modes. The ultraviolet spectra reveal that the addition of an ethynyl group to a non-substituted PAH molecule results in all its electronic transitions being redshifted. Due to fast internal energy conversion, the bands at shorter wavelengths are significantly broadened. Those at longer wavelengths are only barely affected in this respect. As a consequence, their relative peak absorption increases. The substitution with the longer butadiynyl chain causes the same effects with a larger magnitude, resulting in the spectra to show a prominent if not dominating pi-pi* transition at long wavelength. After discussing the relevance of polyynyl-substituted PAHs to astrophysics, we conclude that this class of highly conjugated, unsaturated molecules are valid candidates for the carriers of the diffuse interstellar bands.Comment: 29 pages, 9 figures, accepted for publication in ApJ 2 April 201

Where does the peanut smut pathogen, Thecaphora frezii, fit in the spectrum of smut diseases?

Smut fungi, such as Ustilago maydis, have been studied extensively as a model for plant-pathogenic basidiomycetes. However, little attention has been paid to smut diseases of agronomic importance that are caused by species of the genus Thecaphora, probably due to their more localized distribution. Peanut smut incited by Thecaphora frezii has been reported only in South America, and Argentina is the only country where this disease has been noted in commercial peanut production. In this work, important advances in deciphering T. frezii specific biology/pathobiology in relation to potato (T. solani), wheat (U. tritici), and barley (U. nuda) smuts are presented. We summarize the state of knowledge of fungal effectors, functionally characterized to date in U. maydis and most recently in T. thlaspeos, as well as the potential to be present in other Thecaphora species involved in dicot-host interactions like T. frezii-peanut. We also discuss applicability and limitations of currently available methods for identification of smut fungi in different situations and management strategies to reduce their impact on agri-food quality. We conclude by describing some of the challenges in elucidating T. frezii strategies that allow it to infect the host and tolerate or evade plant immune defense mechanisms, and assessing other aspects related to pest control and their implications for human health.Fil: Arias, Silvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. University of Iowa; Estados UnidosFil: Mary, Verónica Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Velez, Pilar Andrea. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Rodriguez, María G.. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Otaiza González, Santiago Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Theumer, Martín Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentin

Mechanical and thermo-mechanical properties of discontinuously and continuously processed biogenic wood-plastic composites from polyamide 11 and chemically modified beech particles

The resulting mechanical and thermo-mechanical properties of discontinuously and continuously processed biogenic wood-plastic composites (bio-WPC) from polyamide 11 and chemically modified beech particles are investigated. It is found that continuous processing with a twin-screw extruder (TSE) and subsequent industrial scale injection molding leads to a lower elastic modulus, an equal tensile strength, a higher strain at break and a lower glass transition temperature as compared to discontinuous processing with an internal mixer (IM) and subsequent laboratory scale injection molding. This is attributed to a more distinctive beech particle size reduction and shear stress induced chain scission during TSE processing and subsequent injection molding

Improved Synthesis of an Ascaroside Pheromone Controlling Dauer Larva Development in Caenorhabditis elegans

Using an efficient Wacker oxidation as a key step, we describe a significantly improved synthesis of the dauer-promoting ascaroside 2 for biological studies of the novel sterol ring methylase STRM-1

Synthesis and biological activity of the (25R)-cholesten-26-oic acids-ligands for the hormonal receptor DAF-12 in Caenorhabditis elegans

We describe the stereoselective transformation of diosgenin () to (25R)-Delta(4)-dafachronic acid (), (25R)-Delta(7)-dafachronic acid (), and (25R)-cholestenoic acid (), which represent potential ligands for the hormonal receptor DAF-12 in Caenorhabditis elegans. Key-steps of our synthetic approach are a modified Clemmensen reduction of diosgenin () and a double bond shift from the 5,6- to the 7,8-position. In the 25R-series, the Delta(7)-dafachronic acid exhibits the highest hormonal activity

Synthesis and Activity against Mycobacterium tuberculosis of Olivacine and Oxygenated Derivatives

The tetracyclic pyrido[4,3-b]carbazole olivacine and four of its oxygenated derivatives have been synthesized by a late-stage palladium-catalyzed Heck-type cyclization of the pyrrole ring as a key step. In a test for the inhibition of the growth of Mycobacterium tuberculosis, 9-methoxyolivacine showed the most significant inhibitory activity against Mycobacterium tuberculosis, with an MIC90 value of 1.5 μM

Method for event-based production control

Advancements in data processing technologies give companies new opportunities to get current information about their production processes. Within the scope of the present work, an event-based production control system was developed to provide efficient decision-making support based on real-time processing of production-related events. A novel method for an event-based production control was defined. Based on mixed integer linear programming (MILP) the costs caused by the occurrence of events and the costs for taking a measure are minimized The results of the optimization are the base for the decision support. Finally, an application scenario to validate the method is outlined

Subchronic mycotoxicoses in Wistar rats: Assessment of the in vivo and in vitro genotoxicity induced by fumonisins and aflatoxin B1, and oxidative stress biomarkers status

Some evidence suggests that fumonisin B1 (FB1), a worldwide toxic contaminant of grains produced by Fusarium verticillioides, exhibits an oxidative stress mediated genotoxicity. We studied the DNA damage (by the alkaline comet and the micronucleus tests) and biomarkers of cellular oxidative stress malondialdehyde, MDA; catalase, CAT; and superoxide dismutase, SOD) in spleen mononuclear cells of male Wistar rats subchronically (90 days) fed on a control experimental diet (CED) or poisoned with experimental diets contaminated with a culture material containing 100ppm of FB1 (FED), with 40 ppb of aflatoxin B1 (a common toxic co-contaminant in cereals, AFB1ED), and with a mixture of both toxins (MED). The DNA damage was found in 13.7%, 81.7%, 98.0% and 99.3% (comet assay) and in 2.8%, 7.0%, 10.8% and 8.8% (micronucleus technique) in groups CED, FED, AFB1ED and MED, respectively. The MDA levels as well as the CAT and SOD activities were increased in all the poisoned animals. A similar behavior was observed in cells exposed in vitro to the toxins. These data support the hypothesis of an oxidative stress mediated genotoxicity induced by FB1. Furthermore, the extent of DNA damage assessed by the comet assay suggests a possible protective effect of the fumonisins?AFB1 mixtures in vitro against the genotoxicity induced individually by the toxins.Fil: Theumer, Martín Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Cánepa, Mariana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: López, A. G.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Mary, Verónica Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Dambolena, Jose Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Rubinstein, H. R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina; Argentina. Universidad Nacional de Córdoba; Argentin