104 research outputs found
Influence of temperature on production of water-in-oil emulsions by microchannel emulsification
In this paper, we report the influence of temperature on the production characteristics of water-in-oil (W/O) emulsions by microchannel emulsification (MCE). The temperature of an emulsification module including a hydrophobic microchannel (MC) array chip was controlled between 10 °C and 55 °C. The continuous phase was a decane oil solution containing 5 wt% tetraglycerin monolaurate condensed ricinoleic acid ester as a surfactant. The dispersed phase was a Milli-Q water solution containing 1 wt% of sodium chloride and 5 wt% of polyethylene glycol. The contact angle of the dispersed phase to the MC wall exceeded 152°, strongly suggesting that the MC array surfaces are not wetted by the dispersed phase during MCE. At the breakthrough pressure of the dispersed phase, monodisperse W/O emulsions with coefficient of variation below 5% were produced via hydrophobic MC arrays, irrespective of the temperature. At each operating temperature, the resultant droplet diameter was also almost constant below a critical flow velocity of the dispersed phase. The maximum droplet generation rate from a channel gradually increased with increasing operating temperature due to the decrease in viscosity of both phases. An adapted capillary number that considers the influence of the wettability and surfactant adsorption had a low maximum/minimum value ratio of 1.2
QTL mapping for Mediterranean corn borer resistance in European flint germplasm using recombinant inbred lines
<p>Abstract</p> <p>Background</p> <p><it>Ostrinia nubilalis </it>(ECB) and <it>Sesamia nonagrioides </it>(MCB) are two maize stem borers which cause important losses in temperate maize production, but QTL analyses for corn borer resistance were mostly restricted to ECB resistance and maize materials genetically related (mapping populations derived from B73). Therefore, the objective of this work was to identify and characterize QTLs for MCB resistance and agronomic traits in a RILs population derived from European flint inbreds.</p> <p>Results</p> <p>Three QTLs were detected for stalk tunnel length at bins 1.02, 3.05 and 8.05 which explained 7.5% of the RILs genotypic variance. The QTL at bin 3.05 was co-located to a QTL related to plant height and grain humidity and the QTL at bin 8.05 was located near a QTL related to yield.</p> <p>Conclusions</p> <p>Our results, when compared with results from other authors, suggest the presence of genes involved in cell wall biosynthesis or fortification with effects on resistance to different corn borer species and digestibility for dairy cattle. Particularly, we proposed five candidate genes related to cell wall characteristics which could explain the QTL for stalk tunnelling in the region 3.05. However, the small proportion of genotypic variance explained by the QTLs suggest that there are also many other genes of small effect regulating MCB resistance and we conclude that MAS seems not promising for this trait. Two QTLs detected for stalk tunnelling overlap with QTLs for agronomic traits, indicating the presence of pleitropism or linkage between genes affecting resistance and agronomic traits.</p
Identification of genes related to germination in aged maize seed by screening natural variability
Ageing reduces vigour and viability in maize inbred lines due to non-heritable degenerative changes. Besides non-heritable genetic changes due to chromosome aberrations and damage in the DNA sequence, heritable changes during maize conservation have been reported. Genetic variability among aged seeds of inbred lines could be used for association studies with seed germination. The objective of this study was to identify genes related to germination in aged seeds. The sweet corn inbred line P39 and the field corn inbred line EP44 were used as plant material. Bulks of living and dead seeds after 20 and 22 years of storage were compared by using simple sequence repeats (SSRs) and, when the bulks differed for a marker, the individual grains were genotyped. Differences between dead and living seeds could be explained by residual variability, spontaneous mutation, or ageing. Variability was larger for chromosome 7 than for other chromosomes, and for distal than for proximal markers, suggesting some relationships between position in the genome and viability in aged seed. Polymorphic SSRs between living and dead seeds were found in six known genes, including pathogenesis-related protein 2, superoxide dismutase 4, catalase 3, opaque endosperm 2, and metallothionein1 that were related to germination, along with golden plant 2. In addition, five novel candidate genes have been identified; three of them could be involved in resistance to diseases, one in detoxification of electrophillic compounds, and another in transcription regulation. Therefore, genetic variability among aged seeds of inbreds was useful for preliminary association analysis to identify candidate genes
DD04107-Derived neuronal exocytosis inhibitor peptides: Evidences for synaptotagmin-1 as a putative target
The analgesic peptide DD04107 (Pal-EEMQRR-NH2) and its acetylated analogue inhibit α-calcitonin gene-related
peptide (α-CGRP) exocytotic release from primary sensory neurons. Examining the crystal structure of the
SNARE-Synaptotagmin-1(Syt1) complex, we hypothesized that these peptides could inhibit neuronal exocytosis
by binding to Syt1, hampering at least partially its interaction with the SNARE complex. To address this hy
pothesis, we first interrogate the role of individual side-chains on the inhibition of α-CGRP release, finding that
E1, M3, Q4 and R6 residues were crucial for activity. CD and NMR conformational analysis showed that linear
peptides have tendency to adopt α-helical conformations, but the results with cyclic analogues indicated that this
secondary structure is not needed for activity. Isothermal titration calorimetry (ITC) measurements demonstrate
a direct interaction of some of these peptides with Syt1-C2B domain, but not with Syt7-C2B region, indicating
selectivity. As expected for a compound able to inhibit α-CGRP release, cyclic peptide derivative Pal-E-cyclo
[EMQK]R-NH2 showed potent in vivo analgesic activity, in a model of inflammatory pain. Molecular dynamics
simulations provided a model consistent with KD values for the interaction of peptides with Syt1-C2B domain,
and with their biological activity. Altogether, these results identify Syt1 as a potential new analgesic targe
Perceptions of pre-service chemistry teachers on the utilization of productive lesson study as a framework for teaching and learning
The present study determined the perceptions of pre-service teachers on utilizing productive lesson study as a framework in teaching high school chemistry. Participants of the study were thirty (30) junior pre-service chemistry teachers from a state-funded teacher education institution in Manila, Philippines. Participants were exposed to a training-workshop on lesson study and productive pedagogy prior to getting their perception. Lesson study is a form of collaborative lesson planning while productive pedagogy is a framework for evaluating effectiveness of a teaching strategy based on intellectual quality, connectedness, recognition of difference and supportive classroom environment. Results of the study indicated that although most of the participants agreed to utilize the framework, most of them did not grasp the essential process of productive lesson study. On the other hand, all of them agreed that the framework will help improve the teaching skills of teachers and will therefore result to a greater achievement in chemistry among students. Disadvantages that they foresee in the framework include time element and exclusivity. The productive lesson study process will take much of their time and that formulated research lessons might be exclusive only to a group of students and may not be applicable to all
Banbuaren karakterizazio mekanikoa eta kimikoa
The bamboo, a tubular geometry plant, it is a promising replacement of traditional synthetic materials in the construction sector. In addition, it is renewable and environmentally sustainable. However, in order to promote its use, mechanical and chemical properties of bamboo must be known. This work analyses chemical and mechanical characteristics of three bamboo species not used in the construction sector, but widely used for other purposes: Phyllostachys aurea (PA), Arundinaria amabilis (AA) and Dendrocalamus strictus (DS). TAPPI standards have been used for the chemical analysis, while mechanical properties have been studied in compression and three-point flexion tests. The results have shown that the density of bamboo has a direct influence on mechanical properties, both in resistance and stiffness: for the analysed three bamboo species, the higher density the higher resistance and stiffness.; Banbuak, geometria tubularreko landareak, material sintetiko tradizionalen ordezko aukera interesgarriak aurkezten ditu eraikuntzaren sektorerako. Gainera, ingurumenaren aldetik jasangarria eta berriztagarria da. Hala ere, bere erabilera sustatzeko, beharrezkoa da banbuen propietate mekanikoak eta kimikoak ezagutzea. Lan honek gaur egun eraikuntzan ezezagunak diren baina tradizionalki oso erabiliak izan diren hiru espezie aztertzen ditu, kimikoki eta mekanikoki: dendrocalamus strictus (DS), Arundinaria amabilis (AA) eta Phyllostachys aurea (PA). Azterketa kimikorako, TAPPI arauak erabili dira, eta ezaugarri mekanikoak konpresioan eta dinamometroarekin makurdura hiru puntutan neurtuta aztertu dira. Propietate mekanikoen emaitzek erakutsi dute banbuaren dentsitateak eragin zuzena duela bai erresistentzian, bai zurruntasunean. Aztertutako hiru banbu-espezieetan, dentsitatea zenbat eta handiagoa izan, erresistentzia eta zurruntasuna orduan eta handiagoak direla ikusi da
Influencia de la inoculación oral en la enfermedad de Chagas en modelo murino
Objective: Determine the behavior of Chagas´s disease, comparing the intraperitoneal (i.p.), and the oral (i.o.) administration routes, by the ingestion of T. cruzi-contaminated food.
Materials and methods: In mice, parasitemia oral and intraperitoneal acquiring routes were compared. Two groups were inoculated with T. cruzi (3x103)Objetivo: Determinar el comportamiento de la enfermedad de Chagas, comparando la vía de inoculación intraperitoneal (i.p.) y la vía oral (i.o.), mediante la ingestión alimentos infectados con Trypanosoma cruzi (T. cruzi).
Materiales y métodos: En modelo múrido, se comparó la parasitemia en la infección adquirida vía i.p. y vía i.o. Se formaron dos grupos que fueron inoculados con la cepa NINOA de T. cruzi (3x103); uno se administró vía i.o. y otro, se administró vía i.p. Además, se realizó un estudio histopatológico del tejido cardiaco de los individuos. Finalmente, se determinó y comparó la respuesta inmune montada como resultado de la inoculación por ambas vías, evaluando la concentración de IgG séricas contra T. cruzi mediante la realización de una ELISA casera.
Resultados: El comportamiento de la infección fue diferente en ambas vías de inoculación. A través de los métodos parasitoscópicos e histopatológicos empleados no fue detectable la infección en aquellos individuos infectados i.o., interesantemente, la infección sí fue detectable mediante métodos inmunológicos. Aquellos individuos infectados vía i.o. empleando açaí tuvieron un comportamiento inmune similar al presentado por aquellos inoculados vía i.p.
Discusión: La estrecha convivencia con los insectos transmisores facilita la adquisición de la infección mediante diversas vías. Conocer las variantes en el curso de la infección que implica cada vía de inoculación, aumenta el éxito del diagnóstico.
Conclusión: El presente estudio demuestra que la vía de infección del hospedero es determinante para la evolución de la enfermedad. Este hallazgo, representa un área de oportunidad del sector salud para el mejoramiento del diagnóstico de la enfermedad de Chagas (sobre todo en áreas endémicas)
Effect of the alcoholic strength of unaged wine distillates on the final composition of Brandy de Jerez aged in Sherry Casks®
Brandy is a spirit obtained from distilled wine that has an alcohol content equal to or greater than 36 % ABV (Alcohol by Volume). It undergoes an ageing process in oak wood casks with a capacity of up to 1000 L for a minimum of six months. During this process, a series of physicochemical and sensory changes take place that confer the initial wine distillate with a series of improvements to its sensory profile. Such changes are mainly determined by the intrinsic characteristics of the wood and by those associated with the manufacturing process of the casks. The previous use of the casks, ageing time and the alcoholic strength of the wine distillate are also important factors, among others. The casks, which will have previously contained some type of Sherry wine (such as Fino, Amontillado, Oloroso and Pedro Ximénez), are known as Sherry Casks® and they must be used in the production of Brandy de Jerez. During the ageing of Brandy de Jerez, Sherry Casks® contribute to the final brandy via the compounds that are both inherent to the wood they are made of and from the wine that they initially contained and that were retained in the wood pores. The alcohol content of the wine distillate to be aged significantly affects not only the quality of the brandy, but also the financial cost of the process. This study aimed to determine the influence on brandy of the alcoholic strength of wine distillates aged in static ageing systems using Sherry Casks®. Specifically, we assessed the physicochemical composition and sensory profile of Brandy de Jerez made from wine distillates with three different alcoholic strengths (40 %, 55 % and 68 % ABV) and aged for 24 months. The Brandy de Jerez with lower alcoholic strengths (40 % - 55 % ABV) were found to contain a higher concentration of polyphenolic compounds deriving from the wood as well as from the constituents of the cask-seasoning Sherry wine. The brandies with higher alcoholic strengths exhibited a marked colour change, while the 40 % and 55 % ABV brandies were perceived to have the best sensory characteristics
Association mapping for maize stover yield and saccharification efficiency using a multiparent advanced generation intercross (MAGIC) population
Cellulosic ethanol derived from fast growing C4 grasses could become an alternative to finite fossil fuels. With the potential to generate a major source of lignocellulosic biomass, maize has gained importance as an outstanding model plant for studying the complex cell wall network and also to optimize crop breeding strategies in bioenergy grasses. A genome-wide association study (GWAS) was conducted using a subset of 408 Recombinant Inbred Lines (RILs) from a Multi-Parent Advanced Generation Intercross (MAGIC) Population in order to identify single nucleotide polymorphisms (SNPs) associated with yield and saccharification efficiency of maize stover. We identified 13 SNPs significantly associated with increased stover yield that corresponded to 13 QTL, and 2 SNPs significantly associated with improved saccharification efficiency, that could be clustered into 2 QTL. We have pointed out the most interesting SNPs to be implemented in breeding programs based on results from analyses of averaged and yearly data. Association mapping in this MAGIC population highlight genomic regions directly linked to traits that influence the final use of maize. Markers linked to these QTL could be used in genomic or marker-assisted selection programs to improve biomass quality for ethanol production. This study opens a possible optimisation path for improving the viability of second-generation biofuelsPlan Estatal de Ciencia y Tecnología de España | Ref. RTI2018–096776-B-C21Plan Estatal de Ciencia y Tecnología de España | Ref. RTI2018–096776-B-C2
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