Impact properties and water uptake behavior of old newspaper recycled fibers-reinforced polypropylene composites

Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materialsPostprint (published version

Topography of the interfacial shear strength and the mean intrinsic tensile strength of hemp fibers as a reinforcement of polypropylene

The strength of the interphase between the reinforcements and the matrix has a major role in the mechanical properties of natural ¿ber reinforced polyole¿n composites. The creation of strong interphases is hindered by the hydrophobic and hydrophilic natures of the matrix and the reinforcements, respectively. Adding coupling agents has been a common strategy to solve this problem. Nonetheless, a correct dosage of such coupling agents is important to, on the one hand guarantee strong interphases and high tensile strengths, and on the other hand ensure a full exploitation of the strengthening capabilities of the reinforcements. The paper proposes using topographic pro¿le techniques to represent the e¿ect of reinforcement and coupling agent contents of the strength of the interphase and the exploitation of the reinforcements. This representation allowed identifying the areas that are more or less sensitive to coupling agent content. The research also helped by ¿nding that an excess of coupling agent had less impact than a lack of this componentPostprint (published version

Motivations and challenges of an engineering lecturer to implement EMI and innovative methodology

The objective: Explore the drivers for both EMI and teaching innovation.Find out the extent to which they influence each other: does EMI implementation lead to lecturers’ reappraisal of their courses on a level or are innovative lecturers more prone to engage in EMIPeer ReviewedPostprint (published version

The PPARβ/δ-AMPK Connection in the Treatment of Insulin Resistance

The current treatment options for type 2 diabetes mellitus do not adequately control the disease in many patients. Consequently, there is a need for new drugs to prevent and treat type 2 diabetes mellitus. Among the new potential pharmacological strategies, activators of peroxisome proliferator-activated receptor (PPAR)β/δ show promise. Remarkably, most of the antidiabetic effects of PPARβ/δ agonists involve AMP-activated protein kinase (AMPK) activation. This review summarizes the recent mechanistic insights into the antidiabetic effects of the PPARβ/δ-AMPK pathway, including the upregulation of glucose uptake, muscle remodeling, enhanced fatty acid oxidation, and autophagy, as well as the inhibition of endoplasmic reticulum stress and inflammation. A better understanding of the mechanisms underlying the effects resulting from the PPARβ/δ-AMPK pathway may provide the basis for the development of new therapies in the prevention and treatment of insulin resistance and type 2 diabetes mellitus

Desafíos y oportunidades de las herramientas 2.0 para el estudio interdisciplinar de la nutrición: el caso de la Wiki Dieta Mediterránea

En aquest treball s’analitza la possibilitat d’integrar en programes de formació de postgrau de l’àrea de la salut noves pràctiques d’aprenentatge que permetin als estudiants adquirir competències específiques sobre el seu àmbit d’estudi, i alhora millorar altres competències transversals relacionades amb l’ús d’elements propis de la societat de la informació i el coneixement. Amb aquesta intenció es va dur a terme l’experiència wiki dieta mediterrània (wiki DM), una activitat col·laborativa entorn de diferents aspectes de la dieta mediterrània (DM) utilitzant wikispaces.Amb aquesta activitat, d’una banda, es pretenia desenvolupar una visió holística i transdisciplinària del fenomen de l’alimentació, no tan sols des del punt de vista de la seva relació amb la salut, sinó també remarcant-ne la importància del component social, cultural o econòmic; i, de l’altra, es buscava generar i tenir a disposició un conjunt de recursos bibliogràfics actualitzats i fàcilment accessibles sobre el tema, que fossin útils al llarg de tot el procés formatiu. En l’experiència van participar docents i estudiants de diferents programes formatius, de manera que, encara que estiguessin centrats en un àmbit relacionat amb la seva assignatura, pel fet de treballar en un espai comú i amb un objectiu comú poguessin accedir a un conjunt d’informació multidisciplinària i amb una visió més holística de la DM. Després de l’experiència es van analitzar els resultats mitjançant l’avaluació de l’activitat, la participació a la wiki i una enquesta anònima. Els resultats van demostrar que la wiki DM és una eina efectiva per a abordar el fenomen de l’alimentació des de diferents perspectives, i també un sistema útil per a treballar en competències transversals, com ara el domini de les TIC, la cerca bibliogràfica i el treball col·laboratiu.This article analyses the possibility of integrating new learning practices into health-related postgraduate programmes to enable students to acquire specific competencies in their field of study while improving other cross-disciplinary competencies related to the use of elements inherent to the information and knowledge society. To that end, a decision was taken to develop a Mediterranean Diet Wiki experience; a collaborative activity on the different aspects of the Mediterranean diet, using Wikispaces.The activity had two objectives. First, to develop a holistic, transdisciplinary vision of the phenomenon of nutrition, in terms not only of its relationship to health, but also of its importance as a social, cultural and economic component. And second, to have a set of up-to-date, easy-to-access bibliographic resources available on the topic, which would prove useful throughout the students’ educational process. Students and lecturers on different educational programmes took part in the experience. While focusing on a field of study related to their respective subjects, the experience offered them the opportunity to work in a shared space towards a common goal, by providing them with access to a range of multidisciplinary information and a more holistic vision of the Mediterranean diet. On completion of the experience, activity assessment and wiki participation data were analysed, as were data obtained from the anonymous questionnaire. The results showed that the Mediterranean Diet Wiki was an effective tool for approaching the phenomenon of nutrition from different angles, as well as a useful system for working on cross-disciplinary competencies such as the mastery of ICTs, searching effectively for bibliographic references, and collaborative work.En este trabajo se analiza la posibilidad de integrar en programas de formación de posgrado del Área de la Salud nuevas prácticas de aprendizaje que permitan a los estudiantes adquirir competencias específicas sobre su ámbito de estudio, al mismo tiempo que mejorar otras competencias transversales relacionadas con el uso de elementos propios de la sociedad de la información y del conocimiento. Con tal intención se desarrolló la experiencia Wiki DM, una actividad colaborativa en torno a diferentes aspectos de la dieta mediterránea (DM) usandowikispaces.Con esta actividad se pretendía, por un lado, desarrollar una visión holística y transdisciplinar del fenómeno de la alimentación, no solo en su relación con la salud, sino también resaltando la importancia de su componente social, cultural o económico; y, por otro, se buscaba generar y disponer de un conjunto de recursos bibliográficos actualizados y fácilmente accesibles sobre el tema, que fueran de utilidad a lo largo de todo su proceso formativo. En la experiencia participaron docentes y estudiantes de diferentes programas formativos, de manera que, aunque centrados en un ámbito relacionado con su asignatura pero trabajando en un espacio y con un objetivo común, pudieran acceder a una serie de información multidisciplinar y con una visión más holística de la DM. Tras la experiencia se analizaron los resultados mediante la evaluación de la actividad, la participación en la wiki y una encuesta anónima. Los resultados demostraron que la Wiki DM resulta una herramienta efectiva para abordar el fenómeno de la alimentación desde diferentes perspectivas, así como un sistema útil para trabajar en competencias transversales, tales como el dominio de las TIC, la búsqueda bibliográfica y el trabajo colaborativo

STRATEGIC DECISION-MAKING SPEED IN NEW TECHNOLOGY BASED FIRMS

New Technology Based Firms (NTBF) operate in high-velocity environments that make considerable demands about the speed of strategic choices. This study draws upon strategic decision-making and organization theories to propose that strategic decision making speed mediates the relation between personal, organizational and environmental factors and performance. Hypotheses were theoretically developed and tested with data from an empirical investigation of Mexican NTBF. Measures of personal characteristics, organization structure, business environment, strategic decision speed and performance were collected from 103 Technology Founder Managers at the end of 2012. The results confirmed that strategic decision making speed influences the performance of NTBF and mediates the relation of uncertainty, CEO model, dynamism and hostility with firm performance.New Technology Based Firms (NTBF) operate in high-velocity environments that make considerable demands about the speed of strategic choices. This study draws upon strategic decision-making and organization theories to propose that strategic decision making speed mediates the relation between personal, organizational and environmental factors and performance. Hypotheses were theoretically developed and tested with data from an empirical investigation of Mexican NTBF. Measures of personal characteristics, organization structure, business environment, strategic decision speed and performance were collected from 103 Technology Founder Managers at the end of 2012. The results confirmed that strategic decision making speed influences the performance of NTBF and mediates the relation of uncertainty, CEO model, dynamism and hostility with firm performance

Language acquisition in a post-pandemic context: the impact of measures against COVID-19 on early language development

Language acquisition is influenced by the quality and quantity of input that language learners receive. In particular, early language development has been said to rely on the acoustic speech stream, as well as on language-related visual information, such as the cues provided by the mouth of interlocutors. Furthermore, children's expressive language skills are also influenced by the variability of interlocutors that provided the input. The COVID-19 pandemic has offered an unprecedented opportunity to explore the way these input factors affect language development. On the one hand, the pervasive use of masks diminishes the quality of speech, while it also reduces visual cues to language. On the other hand, lockdowns and restrictions regarding social gatherings have considerably limited the amount of interlocutor variability in children's input. The present study aims at analyzing the effects of the pandemic measures against COVID-19 on early language development. To this end, 41 children born in 2019 and 2020 were compared with 41 children born before 2012 using the Catalan adaptation of the MacArthur Bates Communicative Development Inventories (MB-CDIs). Results do not show significant differences in vocabulary between pre- and post-Covid children, although there is a tendency for children with lower vocabulary levels to be in the post-Covid group. Furthermore, a relationship was found between interlocutor variability and participants' vocabulary, indicating that those participants with fewer opportunities for socio-communicative diversity showed lower expressive vocabulary scores. These results reinforce other recent findings regarding input factors and their impact on early language learning

At-line multi-angle light scattering detector for faster process development in enveloped virus-like particle purification

At-line static light scattering and fluorescence monitoring allows direct in-process tracking of fluorescent virus-like particles. We have demonstrated this by coupling at-line multi-angle light scattering and fluorescence detectors to the downstream processing of enveloped virus-like particles. Since light scattering intensity is directly proportional to particle concentration, our strategy allowed a swift identification of product containing fractions and rapid process development. Virus-like particles containing the Human Immunodeficiency Virus-1 Gag protein fused to the Green Fluorescence protein were produced in Human Embryonic Kidney 293 cells by transient transfection. A single-column anion-exchange chromatography method was used for direct capture and purification. The majority of host-cell protein impurities passed through the column without binding. Virus-like particles bound to the column were eluted by linear or step salt gradients. Particles recovered in the step gradient purification were characterized by nanoparticle tracking analysis, size exclusion chromatography coupled to multi-angle light scattering and fluorescence detectors and transmission electron microscopy. A total recovery of 66% for the fluorescent particles was obtained with a 50% yield in the main product peak. Virus-like particles were concentrated 17-fold to final a concentration of 4.45 × 10 particles/mL. Simple buffers and operation make this process suitable for large scale purposes

Endoplasmic reticulum stress downregulates PGC-1α in skeletal muscle through ATF4 and an mTOR-mediated reduction of CRTC2

Background Peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1α (PGC-1α) downregulation in skeletal muscle contributes to insulin resistance and type 2 diabetes mellitus. Here, we examined the effects of endoplasmic reticulum (ER) stress on PGC-1α levels in muscle and the potential mechanisms involved. Methods The human skeletal muscle cell line LHCN-M2 and mice exposed to different inducers of ER stress were used. Results Palmitate- or tunicamycin-induced ER stress resulted in PGC-1α downregulation and enhanced expression of activating transcription factor 4 (ATF4) in human myotubes and mouse skeletal muscle. Overexpression of ATF4 decreased basal PCG-1α expression, whereas ATF4 knockdown abrogated the reduction of PCG-1α caused by tunicamycin in myotubes. ER stress induction also activated mammalian target of rapamycin (mTOR) in myotubes and reduced the nuclear levels of cAMP response element-binding protein (CREB)-regulated transcription co-activator 2 (CRTC2), a positive modulator of PGC-1α transcription. The mTOR inhibitor torin 1 restored PCG-1α and CRTC2 protein levels. Moreover, siRNA against S6 kinase, an mTORC1 downstream target, prevented the reduction in the expression of CRTC2 and PGC-1α caused by the ER stressor tunicamycin. Conclusions Collectively, these findings demonstrate that ATF4 and the mTOR-CRTC2 axis regulates PGC-1α transcription under ER stress conditions in skeletal muscle, suggesting that its inhibition might be a therapeutic target for insulin resistant states