Supernucleation Dominates Lignin/Poly(ethylene oxide) Crystallization Kinetics

The effect of lignin nanoparticles (LNPs) on the crystallization kinetics of poly(ethylene oxide) (PEO) is examined. Lignin from spruce and ionic isolation was used to prepare LNPs with a number-averaged diameter of 85 nm (with a relatively large polydispersity) by an ultrasonication method. PEO-based nanocomposites with four different LNP contents (5, 10, 15, and 20 wt %) were prepared and subject to isothermal and nonisothermal crystallization protocols in a series of experiments. Scanning electron microscopy (SEM) images showed well-dispersed LNPs in the crystallized PEO matrix. The incorporation of LNPs exponentially increases nucleation density at moderate loadings, with this trend apparently saturating at higher loadings. However, the spherulitic growth rate decreases monotonically with LNP loading. This is attributed to the substantial PEO/LNP affinity, which impacts chain diffusion and induces supernucleation effect (with efficiencies in the order of 200%), but leads to slower growth rates. The overall crystallization kinetics, measured by the DSC, shows faster nanocomposite crystallization rates relative to the neat PEO at all LNP contents examined. This indicates that the supernucleation effect of LNPs dominates over the decrease in the growth rates, although its influence slightly decreases as the LNP content increases. The strong hydrogen-bonded interactions between the LNPs and the PEO are thus reminiscent of confinement effects found in polymer-grafted NP nanocomposites (e.g., PEO-g-SiO2/PEO) in the brush-controlled regime.This work received funding from the Basque Government through grant IT1503 - 22. S.K.K . acknowledges funding by the U.S. Department of Energy, Office of Science, grants DE- SC0018182, DE-SC0018135, and DE-SC0018111. The authors acknowledged the financial support of Fundacion Losano, PIP2011 848, and PUE No. 22920160100007 (CONICET) . The authors acknowledge the support of Ana Martínez Amesti, Microscopy: Polymer Characterization Research Service, SGIker (UPV/EHU)

Evaluación del bienestar en vacas en un sistema de ordeñe automatizado durante la época estival. Estudio de caso

Treinta y siete vaquillonas fueron alojadas en un corral con acceso a un tambo robotizado. Poseían sombras de red en el comedero y en los lugares de descanso. Desde las 18:00 hs hasta las 08:00 hs tenían acceso a una pastura. Se registró el comportamiento semanalmente durante 24 horas. Dos veces por semana en 5 horarios, se observó la frecuencia respiratoria. La producción individual se registró diariamente. Semanalmente se analizó la composición de la leche.En dos fechas se realizaron toma de sangre para evaluar el nivel de cortisol. La frecuencia respiratoria media fue de 70 ±12 rpm. La producción de leche fue de 28 ± 1,6 L v-1 d-1. El cortisol presento valores entre 10 y 48 ng ml-1. Los animales destinaron 25,1 % y 26,1 % a las conductas de comer y rumiar respectivamente y sólo 0,7% a beber. Los resultados preliminares indicarían la factibilidad de introducir sistemas robotizados combinados con métodos de mitigación del estrés.Thirty-seven heifers were housed in a pen with access to a robotic dairy farm. They had shadows in the feeder and resting places. From 18:00 hs to 08:00 hs had access a pasture. Behavior was recorded weekly for 24 hours. Twice a week at 5 times the respiratory rate was observed individual production was recorded daily. Weekly dairy control was performed. Two dates blood collection were performed to evaluate the level of cortisol. The average respiratory rate was 70 rpm. Milk production was 28 l v-1 d-1. The present cortisol values between 10 and 48 ng ml-1. Animals des-tined to 25, 1 % and 26, 1 % eating and ruminating behaviors and only 0.7% respectively to drink. The results are preliminary; indicate the feasibility of introducing automated systems combined with stress mitigation methods.EEA RafaelaFil: Leva, Perla E. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Ghiano, Jorge Emanuel Jesús. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Toffoli, Guillermo D. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Fernández, Guillermo B. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Sosa, Jorge Luis. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: García, María Soledad. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Taverna, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Walter, Emilio Gerardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Mitigación del estrés calórico durante el preparto en vacas lecheras

Se utilizaron 30 vacas en preparto que se alojaron en un corral seco con acceso a sombra artifi cial durante el verano. Las vacas fueron distribuidas en dos grupos: sin refrescado (TS) y con refrescado (TR) en el sector comedero. El peso corporal y la condición corporal fueron evaluadas al inicio y a los 25 días. La frecuencia respiratoria se realizó dos veces por semana en cuatro momentos del día. El registro de comportamiento dos veces a la semana. Los datos de analizaron con t Student y χ². El peso y condición corporal no presentaron diferencia signifi cativa. Se observó un efecto del tratamiento en el día y horario para la frecuencia respiratoria (p<0,0001). La conducta de parado a la sombra fue al que dedicaron mayor tiempo en ambos tratamientos 27 % en TS y 29 % en TR. No hubo diferencias en la producción lechera entre TS y TR: 31,4 l/v/d y 30,6 l/v/d respectivamente.Thirty cows in prepartum who stayed in a dry pen with access to artificial shadows were used. The cows were divided into two groups: unrefrigerated (TS) and refrigeration (TR) in the feeder sector. At the start of the trial at 25 days it was evaluated weight and body condition. Twice a week and times of day four respiratory rate was measured. Twice a week the behavior was recorded the data analyzed with T Student and chi square. Weight and body condition showed no significant difference .It observed a treatment effect on the day and time for the respiratory rate (p<0.0001). The behavior of standing in the shadow was the highest in TS 27 % and 29 % in TR. There were no statistical differences in milk production between treatments in the sun and chilled which was 31,4 l /v/d and 30,6 l /v/d. respectively.Fil: Toffoli, Guillermo D. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Leva, Perla E. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Sosa, Jorge Luis. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Ghiano, Jorge Emanuel Jesús. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Fernández, Guillermo B. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: García, María Soledad. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Taverna, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Walter, Emilio Gerardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Sustitución aminoacídica en la enzima lanosterol 14 α-demetilasa de <i>Cryptococcus neoformans</i> involucrada en la resistencia al fluconazol de aislamientos clínicos

The molecular basis of fluconazole resistance in Cryptococcus neoformans has been poorly studied. A common azole resistance mechanism in Candida species is the acquisition of point mutations in the ERG11 gene encoding the enzyme lanosterol 14-α-demethylase, target of the azole class of drugs. In C. neoformans only two mutations were described in this gene. In order to evaluate other mutations that could be implicated in fluconazole resistance in C. neoformans we studied the genomic sequence of the ERG11 gene in 11 clinical isolates with minimal inhibitory concentration (MIC) values to fluconazole of ≥16 μg/ml. The sequencing revealed the G1855A mutation in 3 isolates, resulting in the enzyme amino acid substitution G484S. These strains were isolated from two fluconazole-treated patients. This mutation would not intervene in the susceptibility to itraconazole and voriconazole.Las bases moleculares de la resistencia al fluconazol en Cryptococcus neoformans han sido poco estudiadas. Un mecanismo de resistencia a los azoles en Candida albicans es la adquisición de mutaciones puntuales en el gen ERG11, que codifica la enzima lanosterol 14 α-demetilasa, blanco de las drogas azólicas. En C. neoformans solo 2 mutaciones en este gen han sido descriptas. Con el objetivo de estudiar otras mutaciones que podrían estar implicadas en la resistencia al fluconazol en C. neoformans, realizamos la secuenciación del gen ERG11 de 11 aislamientos clínicos con valores de concentración inhibitoria mínima (CIM) de fluconazol ≥16 μg/ml. En 3 aislamientos, la secuenciación reveló la mutación G1855A, que da como resultado la sustitución aminoacídica G484S. Estos aislamientos fueron recuperados de 2 pacientes tratados con fluconazol. Esta mutación no intervendría en la sensibilidad al itraconazol y al voriconazol.Facultad de Ciencias Veterinaria

Mitigación del estrés calórico en vacas lecheras en un clima subhúmedo

Para evaluar el efecto de la frecuencia de refrescados sobre la producción de leche y marcadores fi siológicos asociados al estrés calórico, durante enero y febrero de 2014, treinta vacas Holstein fueron encerradas desde las 06:00 a 17:00 horas en corrales con sombra artifi cial, libre acceso a comedero y bebedero, y desde las 17:00 a 04:00 con acceso a pastoreo. Fueron asignados a dos tra-tamientos: confort tres refrescados (C; n=15) y tradicional, solo dos refrescados (T; n=15). La tem-peratura corporal y la producción de leche se registraron diariamente. La frecuencia respiratoria y conductas fueron medidas semanalmente. Se calculó el índice de temperatura y humedad (ITH). No se obtuvieron diferencias signifi cativas en la producción. En la frecuencia respiratoria se encontra-ron diferencias signifi cativas, C presentó 18% menos que el T. Una interacción entre tratamiento y fecha se detectó en frecuencia respiratoria (p84. Los animales de C permanecieron 10% menos del tiempo en la sombra que los T. La conducta predominante fue la de parado. Los animales T estuvieron un 60% más de tiempo jadeando que los del confort.The aim of the study was to evaluate the effect of frequency refreshed during the summer on the production of milk and physiological markers associated with heat stress in Holstein cows. During January and February 2014 cows were locked from 06:00 to 17:00 in pens with artificial shade, free access to food and water bowl, and from 17:00 until 04:00 had access to a strip grazing alfalfa. Cows were assigned to treatments: comfort: 3 refreshed daily, one at 11:00 am and the other 2 prior to milking (C; n = 15) and traditional, just 2 prior to milking (T cooled; n = 15 ). Milk production (PL) was recorded daily, while the rectal temperature (RT), respiratory rate (RR) and behavioral behaviors were measured weekly. The ambient temperature and relative humidity were recorded daily. -humidity Temperature index (ITH) was calculated, no significant differences in PL obtained. In FR significant difference was found between treatments. The C group had 18% fewer FR that T. An interaction between treatment and was detected to date in FR (p 84. The animals in group C remained 10% less time in the shade that predominate T beha-vior was to stop. The animals in the traditional group were 60% longer than the comfort pantingEEA RafaelaFil: Ghiano, Jorge Emanuel Jesús. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Leva, Perla E. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Walter, Emilio Gerardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Taverna, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Toffoli, Guillermo D. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: García, María Soledad. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentin

A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass

Laccases are multicopper oxidases that are being studied for their potential application in pretreatment strategies of lignocellulosic feedstocks for bioethanol production. Here, we report the expression and characterization of a predicted laccase (LAC_2.9) from the thermophilic bacterial strain Thermus sp. 2.9 and investigate its capacity to delignify lignocellulosic biomass. The purified enzyme displayed a blue color typical of laccases, showed strict copper dependence and retained 80% of its activity after 16 h at 70 °C. At 60 °C, the enzyme oxidized 2,2′-azino-di-(3-ethylbenzthiazoline sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) at optimal pH of 5 and 6, respectively. LAC_2.9 had higher substrate specificity (kcat/KM) for DMP with a calculated value that accounts for one of the highest reported for laccases. Further, the enzyme oxidized a phenolic lignin model dimer. The incubation of steam-exploded eucalyptus biomass with LAC_2.9 and 1-hydroxybenzotriazole (HBT) as mediator changed the structural properties of the lignocellulose as evidenced by Fourier transform infrared (FTIR) spectroscopy and thermo-gravimetric analysis (TGA). However, this did not increase the yield of sugars released by enzymatic saccharification. In conclusion, LAC_2.9 is a thermostable laccase with potential application in the delignification of lignocellulosic biomass.Science, Faculty ofNon UBCMicrobiology and Immunology, Department ofReviewedFacult