4,619 research outputs found
Staurosira magallanesica, a replacement name for Staurosira patagonica
Staurosira patagonica M.L.Garcia, Maidana, Ector & E.Morales described a new species found in material of Maar Magallanes, Patagonia, Argentina and other lakes in southern Patagonia. This new species was analysed in detail by light and electron microscopy and a comprehensive description is given in Garcia et al. (2017: 107, 114, figs 2-45). However, this name is a later homonym of Staurosira patagonica Cleve, 1882. If we compare our species to Cleve’s illustration (Cleve 1882: pl. 16: fig. 13), we can easily differentiate the two by their general valve outline and morphometric data. As pointed out by Garcia et al. (2017), re-examination of the type material of members of the Fragilariaceae is needed to confirm identities, establish taxonomic boundaries and to facilitate identification, and this is also the case with Staurosira patagonica Cleve. A new name is, however, required for Staurosira patagonica M.L.Garcia, Maidana, Ector & E.Morales as it is an illegitimate name: Staurosira magallanesica M.L.Garcia, Maidana, Ector & E.Morales nom. nov. Replaced synonym: Staurosira patagonica M.L.Garcia, Maidana, Ector & E.Morales Nova Hedwigia, Beiheft 146: 107, 114, figs 2-45, 2017, nom illeg., non Staurosira patagonica Cleve 1882 Öfversigt af Kongliga Svenska Vetenskaps-Akademiens Förhandlingar 38(10): 13, pl. 16: fig. 13, 1882 ‘1881’. Etymology: we have derived the specific epithet from the name of the paleolake Maar Magallanes where this new species was found for the first time by N.I. Maidana (Maidana & Corbella 1997).Fil: García, María Luján. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Maidana, Nora Irene. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Ector, Luc. Luxembourg Institute of Science and Technology; LuxemburgoFil: Morales, E. A.. Universidade de Évora; Portuga
N-nitrosopiperidina y N-nitrosodibutilamina (II): relevancia en la carcinógenesis química y genotoxicidad
La N-nitrosopiperidina (NPIP) y la N-nitrosodibutilamina (NDBA) han sido clasificadas como posibles carcinógenos en humanos. La NPIP causa tumores en esófago, y también en cavidad nasal, hígado y estómago, mientras que la NDBA es carcinógeno de vejiga urinaria. Ambas N-nitrosaminas son consideradas carcinógenos genotóxicos indirectos puesto que necesitan una bioactivación para generar metabolitos que reaccionen con el DNA. La principal lesión al DNA inducida por las N-nitrosaminas es el daño alquilativo. En el caso de la NDBA, la posición de alquilación es en el O6 de la guanina, formando la O6 butilguanina y la O6-4-hidroxibutilguanina. Sin embargo, esta N-nitrosamina alquila preferentemente proteínas. Por otra parte, la bioactivación de la NPIP genera metabolitos que reaccionan con el N2 de la guanina in vitro, aunque se desconocen sus efectos in vivo. Además, durante la activación metabólica pueden también producirse especies reactivas del oxígeno (EROs) y del nitrógeno (ERNs). Las lesiones oxidativas y nitrativas más comunes son la 8- hidroxideoxiguanosina (8 OHdG) y la 8-nitroguanina, respectivamente, que producen mutaciones y conducen a la carcinogénesis.N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA) have been classified as possibly carcinogenic to humans. NPIP causes tumours in oesophagus, and also in nasal cavity, liver and stomach, whereas NDBA is a bladder carcinogen. Both N-nitrosamines are considered indirect genotoxic carcinogens since they need a bioactivation to generate metabolites that react with DNA. The main DNA lesion induced by N nitrosamines is the alkylative damage. In the case of NDBA, the alkylation position is in O6 of guanine, forming O6 butylguanine and O6-4-hydroxybutylguanine. However, this N-nitrosamine alkylates proteins preferably. On the other hand, NPIP bioactivation generates metabolites that react with N2 of guanine in vitro, although its in vivo effects are unknown. Moreover, during metabolic activation reactive oxygen species (ROS) and nitrogen species (RNS) can be also produced. The most common oxidative and nitrative lesions are 8-hydroxydeoxyguanosine (8-OhdG) and 8-nitroguanine, respectively, that produce mutations and lead to carcinogenesis
N-nitrosopiperidina y N-nitrosodibutilamina (I): formación, exposición humana y metabolismo
Los vegetales, el agua de bebida y los productos cárnicos son las principales fuentes de exposición de nitratos en humanos. La toxicidad de estos compuestos es resultado de su conversión en nitritos que actúan como agentes nitrosantes en la formación de las Nnitrosaminas. Las N-nitrosaminas son uno de los grupos de agentes carcinogénicos más estudiados y existe una gran preocupación debido a su presencia en nuestra vida diaria. Sin embargo, son muy escasos los estudios realizados con dos N-nitrosaminas, la Nnitrosopiperidina (NPIP) y la N-nitrosodibutilamina (NDBA). La NPIP se encuentra en productos cárnicos que incluyan especias en la formulación de sus mezclas y la NDBA en productos cárnicos envasados en goma y en chupetes y tetinas para biberones. Además, la NPIP y la NDBA son compuestos genotóxicos indirectos que necesitan una activación metabólica para dañar el DNA y ejercer su efecto carcinogénico. Este proceso es llevado a cabo por el citocromo P450, en concreto, por las isoformas enzimáticas CYP 2A6 y el CYP 1A1, respectivamente.Vegetables, drinking water and meat products are the main sources of exposure to nitrates in humans. The toxicity of these compounds is usually the result of the conversion of nitrates into nitrites, which act as nitrosating agents in the N-nitrosamine formation. N-nitrosamines are one of the most studied carcinogenic group and great concern exists due to its presence in our daily life. However, the performed studies with two N-nitrosamines, N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA), are very limited. NPIP is found in meat products with spices in their formulation and NDBA in meat products packed in rubber nettings and in pacifiers and nipples. Moreover, NPIP and NDBA are indirect genotoxic compounds that need a metabolic activation to damage DNA and exert their carcinogenic effect. This process is carried out by cytochrome P450, in particular, by enzymatic isoforms CYP 2A6 y el CYP 1A1, respectively
The influence of the perceived requirements of the next match and motivation on the mental fatigue of soccer players
The high cognitive and/or emotional demands of competition can lead to a state of mental fatigue which has shown to be detrimental to soccer performance. However, there is a need to further understand the true mental demands of soccer players. The aim of the present study was to analyze the influence of motivation and the perceived requirements of the next match on mental fatigue perceived by soccer players over the passing of a season. The combined effect of both variables on the perception of mental fatigue, as well as the influence of the time of the season on perceived mental fatigue, were also analyzed. Twenty-six semi-professional Spanish male players (M = 26.31 ± 5.18 years) participated in the present study, conducted during the 2020-2021 season. Perceived mental fatigue and motivation were measured at each training session. The perceived requirements of the next match were also measured in each of the competitive weeks. Linear mixed models were run with R Studio to examine the influence of motivation and the perceived difficulty of the next match on perceived mental fatigue, the combined effect of both variables on perceived mental fatigue, and the influence of the passing of the season on perceived mental fatigue. The results showed a negative and significant influence of motivation on perceived mental fatigue (p < 0.001) and a positive and significant influence of the perceived requirements of the next match on perceived mental fatigue (p < 0.001). Regarding the combined effect, there was a positive and significant effect (p < 0.01) of the perceived difficulty of the next match on the relation between motivation and perceived mental fatigue. A negative influence of season passage on perceived mental fatigue levels was found (p < 0.001). We recommended coaches to consider using the most motivating training tasks when higher next-match requirements are perceived and to be careful with avoidance strategies for mental fatigue, especially at the beginning of the season
Evaluación del comportamiento a la fatiga de másticos bituminosos reforzados con poliolefinas a través de una metodología basada en energía disipada
Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 ºC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 ºC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.El uso de polímeros mejora la resistencia a la fatiga de los másticos asfálticos. Sin embargo, se pueden obtener resultados no esperados si el polímero no se integra eficientemente en el ligante bituminoso. El objetivo de este trabajo es evaluar el efecto de la adición de 3 poliolefinas sobre el comportamiento a la fatiga. Se seleccionaron polietilenos de baja y alta densidad (PEBD y PEAD) y polipropileno (PP) que se usaron al 4 % en peso. Se empleó una metodología basada en la energía disipada, a 25 ºC. Se realizaron ensayos dinámicos de barrido de tiempo en el límite y por encima del intervalo de viscoelasticidad lineal, que demostraron un mejor comportamiento para el mástico que contenía PEBD. Para él, se observó a través de microscopía óptica de fluorescencia que la distribución de polímero en el betún era mucho más homogénea, y éste podría ser el motivo del comportamiento mejorado
Estudio clínico morfológico de la deformación del borde dorsal del cuello del burro de raza andaluza
The aim of this study was to a clinical, morphological of deformation dorsal neck edge on donkeys Andalusian in Bodonal de la Sierra, Extremadura, Spain. We studied a total of 31 donkeys. Clinical examination was performed and morphological considering weight and body condition was measured cervical perimeter. Deformation of the dorsal edge of the neck in all cases studied was evident. Morphological study was to consider the deformation of the dorsal edge of the neck considering the crest of the neck (score of 1 to 5) evidenced. 0 and 1 score-no donkey under these categories. Score 2 - 42 % Score. 3 - 32% score. 4 - 3 % and score 5 - 23%. The statistical results of the peso versus the cervical neck circumference showed a correlation coefficient of 0.773 and the score grade obese neck and body condition was 0.240. In conclusion lesions consistent with deformation of the dorsal edge of the neck in Andalusian breed donkeys were observed.Se plantea como objetivo un estudio clínico morfológico de la deformación del borde dorsal del cuello en burros de raza Andaluza en Bodonal de la Sierra, Extremadura-España. Fueron estudiados un total de 31 burros. Se practicó un examen clínico y morfológico considerando condición corporal peso y se midió el perímetro cervical. Se evidenció deformación del borde dorsal del cuello en todos los casos estudiados. El estudio morfológico para considerar la deformación del borde dorsal del cuello considerando la cresta de la nuca (puntuación del 1 al 5) evidencio: para Puntuación 0 y 1.- ningún burro bajo estas categorías. Puntuación 2.- 42%, Puntuación 3.- 32%, Puntuación 4.- 3% y Puntuación 5.- 23%. Los resultados estadísticos del peso versus el perímetro cervical del cuello presentaron un coeficiente de correlación de 0.773 y para el grado puntuación del cuello obeso y condición corporal fue de 0.240. En conclusión se observaron lesiones compatibles con la deformación del borde dorsal del cuello en burros de raza Andaluza
1,3-Bis[(naphthalen-2-ylsulfanyl)methyl]benzene
Molecules of the title compound, C28H22S2, are located on a crystallographic mirror plane with one half-molecule in the asymmetric unit. The dihedral angle between the phenyl ring and the naphthyl unit is 83.14 (7)°. In the crystal, molecules are interconnected by C—H⋯S and C—H⋯π interactions
Editorial: New insights into adult neurogenesis and neurodegeneration: challenges for brain repair
The formation of new neurons in the brain is probably one of the most controversial topics in the scientific community since in the 1960's Joseph Altman described for the first time that proliferating cells give rise to new neurons in the adult brain of rats and other mammals. This Research Topic includes 1 brief research report, 3 mini review, 4 review and 9 original research papers gathering different contributions highlighting new developments in the field of neurogenesis
Chronic Elevation of Liver Enzymes in Acute Intermittent Porphyria Initially Misdiagnosed as Autoimmune Hepatitis
Autoimmune hepatitis is a disease characterized by an elevation of liver enzymes, as well as specific autoantibodies. It is more common in women than men. We describe a 32-year-old woman with elevated transaminases, autoantibodies, and a liver biopsy result suggestive of autoimmune hepatitis. The indicated treatment was administered without showing a satisfactory response. The patient had a family history of acute intermittent porphyria (AIP) so we decided to begin treatment with hematin, achieving a complete remission of the symptoms. Acute intermittent porphyria is a rare condition characterized by neurovisceral symptoms, abdominal pain being the most common of them. The disease has a higher prevalence among young women and certain European countries such as Sweden, Great Britain, and Spain. A correct diagnosis and prompt treatment are essential because patients affected by AIP must have a strict followup due to the fatal outcome of the outbreaks
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