Micro- and nanotechnology are tools being used strongly in the area of food technology. The electrospray technique is booming because of its importance in developing micro- and nanoparticles ...containing an active ingredient as bioactive compounds, enhancing molecules of flavors, odors, and packaging coatings, and developing polymers that are obtained from food (proteins, carbohydrates), as chitosan, alginate, gelatin, agar, starch, or gluten. The electrospray technique compared to conventional techniques such as nanoprecipitation, emulsion–diffusion, double-emulsification, and layer by layer provides greater advantages to develop micro- and nanoparticles because it is simple, low cost, uses a low amount of solvents, and products are obtained in one step. This technique could also be applied in the agrifood sector for the preparation of controlled and/or prolonged release systems of fertilizer or agrochemicals, for which more research must be conducted.
Abstract
Polyisocyanurate (PIR) foam is a thermal insulating material widely used in many industries such as construction, refrigeration, piping/tubing among others. In this research the production, ...characterization and modeling of the thermal conductivity of PIR foams synthesized with a hydrofluorolefin (HFO 1233zd (E)) as physical foaming agent have been studied. The results have shown that increasing the amount of HFO reduces the density, but the cellular structure is not modified. The relative mechanical properties are the same for the concentrations of HFO considered. In addition, the aging of thermal conductivity as a function of time has been studied in detail. The experimental results have been deeply analyzed using a theoretical model to predict the thermal conductivity The results show that the thermal conductivity and the rate of aging at early stages are reduced for the higher concentrations of HFO. This result has been related to the lower temperature reached during the foaming reaction for higher contents of the physical blowing agent.
Homogeneous and thin porous membranes composed of oriented fibers were obtained from wheat gluten (WG) using the electrospinning technique. SEM micrographs showed an asymmetric structure and some ...porosity, which, in addition to a small thickness of 40 mm, are desirable characteristics for the membranes’ potential application in release systems. The membranes were loaded with urea to obtain pastilles. FT-IR and DSC studies confirmed the existence of interactions via hydrogen bonding between urea and WG proteins. The pastilles were studied as prolonged-released systems of urea in water. The release of urea during the first 10 min was very fast; then, the rate of release decreased as it reached equilibrium at 300 min, with a total of »98% urea released. TGA analysis showed that the release system obtained is thermally stable up to a temperature of 117 °C. It was concluded that a prolonged-release system of urea could be satisfactorily produced using WG fibers obtained by electrospinning for potential application in agricultural crops.
Abstract
Larvae of water scavenger beetles (Coleoptera: Hydrophiloidea) are adapted to a wide variety of aquatic habitats, but little is known about functional and evolutionary aspects of these ...adaptations. We review the functional morphology and evolution of feeding strategies of larvae of the families Hydrophilidae and Epimetopidae based on a detailed scanning electron microscope (SEM) analysis, analysis of video records of feeding behaviour and observations of living larvae. There are two main types of feeding mechanisms: chewing and piercing-sucking. The character mapping using the latest phylogenetic hypothesis for Hydrophiloidea infers the chewing system as the ancestral condition. The piercing-sucking mechanism evolved at least four times independently: once in Epimetopidae (Epimetopus) and three times in Hydrophilidae (Berosini: Berosus + Hemiosus; Laccobiini: Laccobius group; Hydrobiusini: Hybogralius). The piercing-sucking apparatus allows underwater extra-oral digestion and decreases the dependence of larvae on an aerial environment. A detailed study of the tracheal morphology of the piercing-sucking lineages reveals four independent origins of the apneustic respiratory system, all of them nested within lineages with piercing-sucking mouthparts. We conclude that piercing-sucking mouthparts represent a key innovation, which allows for the subsequent adaptation of the tracheal system, influences the diversification dynamics of the lineages and allows the shift to new adaptive zones.
The primary and secondary chaetotaxy of the head capsule and head appendages of the three larval instars of the water scavenger beetle genus Derallus Sharp are described for the first time based on ...two species: D. angustus Sharp and D. paranensis Oliva. Morphometric characters derived from the head capsule and mouthparts are included, together with detailed illustrations of all characters. Chaetotaxy of these larvae is compared with that of Regimbartia attenuata (Fabricius), another species belonging to the Derallus-clade of Berosini.
Abstract
The Coronavirus Disease of 2019 (COVID-19) pandemic caused by SARS-CoV-2 led the Spanish government to impose a national lockdown in an attempt to control the spread of the infection. ...Mobility restrictions and the requirement of a medical prescription for serological testing for COVID-19 were included among the control measures. Under this scenario, between April 15th and June 15th, 2020, we performed an observational study including 449 individuals allowed to be tested according to the governmental restrictions, i.e. fulfilling the following prescription requirements: manifestation of COVID-19-compatible symptoms, contact with a confirmed COVID-19 patient, or employment as an essential worker, including health care workers, firefighters and public safety personnel such as police. Importantly, a relevant feature of the studied cohort was that none of the participants had been hospitalized. We analyzed SARS-CoV-2 IgG seropositivity in this specific cohort, uncovering intrinsic features of great demographic interest. The overall rate of IgG seropositivity was 33.69% (95% CI: 29.27–38.21). This frequency was comparable among the different participant occupations. A RT-PCR positive test, contact with a household member previously tested positive and the presence of COVID-19-compatible symptoms were positively associated with IgG + results. Among these symptoms, ageusia/anosmia was positively and independently associated with SARS-CoV-2 IgG seropositivity, while odynophagia was inversely associated. However, fever, ageusia/anosmia and asthenia were the most frequent symptoms described by IgG + subjects. Therefore, our data illustrate how specific cohorts display particular characteristics that should be taken into account when studying population-wide SARS-CoV-2 seroprevalence and key defining symptoms of COVID-19.
PID controllers are widely used and adaptable to various types of systems. However, for the response to be adequate under different conditions, the PID gains must be adjusted. The tuning is made ...according to the difference between the reference value and the real value (error). This work presents a self-adjusting PID controller based on a backpropagation artificial neural network. The network calculates the appropriate gains according to the desired output, that is, the dynamic response desired which is composed of the transient part and the stationary part of the step response of a system. The contribution of the work is that in addition to using the error for network training, the maximum desired values of overshoots, settling times, and stationary errors were used as input data for the network. An offline training database was created using genetic algorithms to obtain the dynamic response data associated with PID gains. The genetic algorithm allows getting data in different operating ranges and allows using only stable gains combinations. The database was used for training. Subsequently, the neural network estimates an appropriate gain combination, adapting to the error and the desired response. The method performance is evaluated by controlling the speed of a direct current motor. The results indicate an average error of 4% for the database between the requested and system response. On the other hand, the gains estimated by the network in the test dataset (1544 combinations) did not cause instability and complying with the expected dynamic response in 86% of the dataset.
Introducción: Actualmente la obesidad se ha convertido en un problema de salud pública emergente y complejo, cuyo mecanismo es etiopatogénico y multifactorial. Ha sido estudiada desde el enfoque ...biomolecular, genético y mediante intervenciones para mejorar los estilos de vida; sin embargo, no se han incluido estudios que relacionen la autoeficacia y resiliencia en este problema.Objetivo: Evaluar la relación de autoeficacia para el control de peso con la resiliencia, en mujeres mexicanas.Metodología: Estudio correlacional transversal, en 174 mujeres, con o sin obesidad, inscritas en un centro de capacitación para el trabajo en Puebla y San Luis Potosí, México, se empleó muestreo no probabilistico. Se aplicó el instrumento validado en población mexicana: Inventario de Autoeficacia para el control de peso y Escala de Resiliencia Mexicana; con alfa de Cronbach .945 y .950 respectivamente; estudio realizado con apego a la Ley General de Salud en materia de investigación. El análisis de los resultados fue con estadística descriptiva, pruebas de normalidad y correlación r de Spearman. Resultados: El promedio de edad fue 34.6 ± 14.7, media de IMC 26.4 ± 4.5, 49.7 % y 81.7 % obtuvo niveles de autoeficacia y resiliencia altos respectivamente. La relación fue positiva, tamaño de efecto medio y estadísticamente significativo p=.001,con una varianza explicada del 22.6%.Conclusiones: Las mujeres mexicanas mostraron que a mayor resiliencia mayor autoeficacia para el control de peso. Se sugiere integrar la resiliencia en el manejo de la obesidad, que permita el desarrollo de mecanismos para la adquisición de estilos de vida saludables más sustentables.
Self‐regulation is generally considered a process of constraining appetitive desire motivation toward goal‐inconsistent objects and actions through rationality‐based (volitive) motivation. The ...predominant temptation‐focused view of appetitive desire focuses on cravings and self‐control dilemmas, overlooking the beneficial role of appetitive desire in motivating many types of goal‐directed action intentions. We extend this line of research based in the philosophy of action theoretical perspective by proposing that appetitive desire is broader than cravings and it positively influences goal‐consistent action intentions by strengthening volitive desire motivation. Appetitive desire toward goal means containing pleasurable features provides reasons for enacting goal‐consistent actions, which energizes intention formation through volitive desire. Thus, appetitive desire often plays an instrumental rather than detrimental motivational role in reasoned action toward goal pursuit. Three studies, one measurement‐based and two experimental, involving different goal‐directed action contexts, demonstrate that goal means associated with high (vs. low) appetitive desire result in greater volitive desire, which strengthens intentions to enact the goal means. Our results contribute to an expanded understanding of appetitive desire, beyond craving and temptation, as a positive antecedent in the causal sequences of appetitive desire→volitive desire→intentions in the context of consumer goal pursuit.
The subfamily Chaetarthriinae includes morphologically distinct larvae that are adapted to a diversity of environments. Based on larval characters, cladistic analyses (maximum parsimony (MP) and ...Bayesian inference (BI) with homoplasy as a partitioning scheme) were performed to test the monophyly of the subfamily and the relationships of the two tribes included in it: Chaetarthriini and Anacaenini. The chaetotaxy of a third instar larva
Guyanobius adocetus
is described and illustrated in detail, including morphometric characters. This larva is compared to those of the known larvae of the tribe Chaetarthriini belonging to the genus
Chaetarthria
, and
Pseudorygmodus
,
Crenitis
, and
Crenitulus
from Anacaenini. None of the unconstrained analyses recover Chaetarthriinae as monophyletic.
Chaetarthria
diverges in an early branch, probably due to a series of unique morphological modifications associated with a riparian lifestyle whereas
Guyanobius
appears closely related to Anacaenini. Two alternative positions of
Guyanobius
are revealed: (1) as sister of all Anacaenini (unconstrained MP) or (2) nested within Anacaenini as sister of
Crenitis
+
Crenitulus
(constrained MP and unconstrained BI). The genera
Paracymus
and
Tormus
(tribe Laccobiini) diverge as two successive branches subordinate to Chaetarthriinae (excluding
Chaetarthria
) in the unconstrained MP analysis. However, the support is rather weak, and the position of
Paracymus
and
Tormus
is an artifact produced by some homoplastic characters. In this regard, homoplasy partitioning resulted a useful technique to solve some artifacts generated by convergent morphologies.
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