Diverse functions for the semaphorin receptor PlexinD1 in development and disease

AbstractPlexins are a family of single-pass transmembrane proteins that serve as cell surface receptors for Semaphorins during the embryonic development of animals. Semaphorin–Plexin signaling is critical for many cellular aspects of organogenesis, including cell migration, proliferation and survival. Until recently, little was known about the function of PlexinD1, the sole member of the vertebrate-specific PlexinD (PlxnD1) subfamily. Here we review novel findings about PlxnD1's roles in the development of the cardiovascular, nervous and immune systems and salivary gland branching morphogenesis and discuss new insights concerning the molecular mechanisms of PlxnD1 activity

Superficial Surface Treatment using Atmospheric Plasma on Recycled Nylon 6,6

Polymers currently represent materials that are cost-effective, while its recycled nature is significant in terms of environmental protection. However, the surface properties of polymers often do not meet the demands of wettability, adhesion, and friction, among others. Atmospheric plasma treatment on the surface of polymers improves its physical-chemistry properties. In this work, a recycled nylon coating was prepared by the spin coating technique and characterized by Fourier transform infrared spectroscopy and X-ray diffraction. This coating was treated by atmospheric plasma, and Raman spectroscopy was performed to analyze the signals related to different functional groups present in the coating surface after plasma treatment. The action of plasma on the surface morphology was observed by scanning electron microscopy. The contact angle results showed an improvement in surface wettability

Estudio de las relaciones de compatibilidad en estado sólido del diagrama de equilibrio de fases CaO-Al2O3-CoO

En este trabajo se presenta el estudio de las relaciones de compatibilidad en estado sólido del diagrama de fases ternario CaO-Al2O3-CoO. Los resultados se obtuvieron en la línea de subsólidos a 1300ºC, donde se determinó la existencia de nueve triángulos de compatibilidad en estado sólido.Se encontró una nueva fase de fórmula Ca3CoAl4O10, la cual es isoestructural a Ca3MgAl4O10. Se delimitaron tres pequeñas regiones de soluciones sólidas alrededor de CaO, CoO y CoAl2O4. Se observó también la formación de fases con diversos colores en función de la zona del diagrama. Por otro lado, al sustituir Co por otros cationes bivalentes (Sr, Ba, Mn, Ni, Cu, Cd, Sn y Pb), no se encontraron nuevas fases ternarias

A technological acceptance of e-learning tools used in practical and laboratory teaching, according to the European higher education area

The application of scientific tools to analyse the use of Internet-based e-learning tools in academic settings is in general an ignored area. E-learning tools are actually an emergent topic as a result of the new ideas introduced by the European Higher Education Area. Lifelong learning, or the promotion of student initiative, is the new paradigm of a learner-centred education. In this context, e-learning tools can represent an effective way of supporting this new trend in education. Assuming the premise that successful use of these web-based tools depends primarily on a user’s behaviour, the objective of this research is to examine the technology acceptance model (TAM) of web-based elearning tools used in practical and laboratory teaching. The research hypotheses derived from this model have empirically been validated using the responses to a survey on e-learning usage among 220 users. These responses have been examined through partial least square. The obtained results strongly support the extended TAM in predicting a student’s intention to use e-learning and define a set of external variables with a significant influence in the original TAM variables. Surprisingly, perceived ease of use did not posit a significant impact on student attitude or intention towards e-learning tool usage. Therefore, early evaluation of e-learning material is considered essential to providing a framework for further improvements of the too

Lipid and protein changes related to quality loss in frozen sardine (Sardina pilchardus) previously processed under high-pressure conditions

This research focuses on biochemical changes related to quality loss in frozen (−18 °C for 9 months) sardine (Sardina pilchardus) previously subjected to high-pressure (HP) processing (125–200 MPa). The inhibition (p < 0.05) of lipid hydrolysis development (lower free fatty acid formation and lipase activity), observed in frozen sardine as a result of the previous HP treatment, increased with the pressure level applied. Several parameters including peroxide value, thiobarbituric acid index, fluorescent compounds, and polyenes showed that the applied HP conditions prior to sardine freezing did not increase lipid oxidation. Also, HP did not induce a substantial modification of acid phosphatase and cathepsins B and D activities, and the electrophoretic patterns of sarcoplasmic and myofibrillar protein fractions did not change. However, HP processing led to a decrease in myofibrillar protein content in frozen pressure-treated fish, an effect that was higher in 175- and 200-MPa treated samples. In conclusion, this research showed that pressure treatments in the 125–200- MPa range with holding time of 0 min cause only minor modifications in biochemical indicators of deterioration throughout the subsequent frozen storage of samples for up to 9 months. This study shows the need to optimize HP conditions, particularly in the case of applications combining HP treatments, frozen storage, and thawing to obtain products with high quality and commercial viability

Effect of high-pressure processing of Atlantic mackerel (Scomber scombrus) on biochemical changes during commercial frozen storage

This research focuses on biochemical changes related to quality losses observed in Atlantic mackerel (Scomber scombrus) muscle stored under commercial frozen storage conditions (9 months, −18 °C) when subjected to highhydrostatic pressure (HHP) treatments (125, 150, 175, and 200 MPa for 0 min) before freezing. After freezing, free fatty acid (FFA) formation (lipid hydrolysis assessment) showed a marked inhibition in HHP-treated fish and during frozen storage of samples treated at 175 MPa. Fluorescence ratio (FR) assessment of tertiary lipid oxidation showed a partial inhibitory effect during the 0–9-month period for samples treated at 175 and 200 MPa. After a 3-month storage of samples treated at these pressure levels, one-dimensional SDS-PAGE analysis of the sarcoplasmic protein fraction revealed the disappearance of a band; additionally, samples treated at 150 MPa showed the same effect at month 9. After gel excision, trypsin digestion, tandem mass spectrometry (MS/MS), and sequence database analysis, the band was identified as phosphoglycerate mutase 2 (28.7 kDa). On the other hand, HHP processing did not show a significant effect on trimethylamine (TMA) values, primary and secondary lipid oxidation, PUFA levels, 1-D myofibril protein pattern, and the activity of acid phosphatase and cathepsins B and D. Biochemical quality indices such as FFA, TMA, and FR and the activity of acid phosphatase and cathepsin B showed a progressive increase throughout the frozen storage of all samples

Addressing learner satisfaction outcomes in electronic instrumentation and measurement laboratory course organization

This paper proposes and details a course organization methodology based on learner satisfaction achievement. The approach follows the prevailing tendency in modern university reforms which are primarily concerned about “how people learn.” As a consequence, the learner has been placed as the main actor of the teaching–learning process. Nevertheless, the current learning literature has not addressed the measurement of learner satisfaction within laboratory and practical subjects. This study develops a general and comprehensive methodology for learner satisfaction measurement in practical subjects. As a case example, the proposed methodology has been applied to an electronic instrumentation and measurement course, confirming the variables with a significant influence on learner satisfaction and becoming the starting point for curriculum redesign based on the learner satisfaction approach. To assess the improvement of the proposed course organization methodology, a comparison with previous academic years has been performed showing the students’ rated score evolution. Results fully confirm the validity of the technique and the novel course organizatio

An electronic engineering curriculum design based on concept-mapping techniques

Curriculum design is a concern in European Universities as they face the forthcoming European Higher Education Area (EHEA). This process can be eased by the use of scientific tools such as Concept-Mapping Techniques (CMT) that extract and organize the most relevant information from experts’ experience using statistics techniques, and helps a working group to achieve conclusions. This paper presents an empirical exploratory research study related to the application of the CMT to the design of the Electronic Engineering (EE) Degree at the University of Seville, Spain. Considering the Career-space conclusions as the initial point, the main relevant competences were identified in a brainstorming technique. These competences are organized according to their affinity using CMT, establishing and interpreting the main clusters and their relative importance. Finally, a reliability analysis of the concept maps was carried out verifying the correctness of the procedure and validating the results for the curricula adaptatio

Modeling learner satisfaction in an electronic instrumentation and measurement course using structural equation models

The prevailing tendency in modern university reforms is towards “how people learn,” following a learner-centered approach in which the learner is the main actor of the teaching-learning process. As a consequence, one of the key indicators of the teaching-learning process is the measurement of learner satisfaction within the classroom. Learner satisfaction has traditionally been measured using survey responses to a standard learning survey. However, more scientific analysis should be performed to assess adequately not only learner satisfaction but also the main dimensions that have a positive impact on learner satisfaction. The purpose of this paper is to define a structural and measurement model in which causal relationships among these different dimensions are adequately established. The methodology is based on a multivariate regression model (Structural Equation Models) to establish scientifically a structural model for learner satisfaction within a classroom, measuring its validity and reliability. The proposed approach has been applied to model learner satisfaction in an electronic instrumentation course at the University of Seville, Spain. The results and implications of this study will contribute to improve student satisfaction with respect to the dimensions considere