Regulation of human feto-placental endothelial barrier integrity by vascular endothelial growth factors: competitive interplay between VEGF-A165a, VEGF-A165b, PIGF and VE-cadherin

The human placenta nourishes and protects the developing fetus whilst influencing maternal physiology for fetal advantage. It expresses several members of the VEGF family including the pro-angiogenic/pro-permeability VEGF-A165a isoform, the anti-angiogenic VEGF-A165b, placental growth factor (PIGF) and their receptors, VEGFR1 and VEGFR2. Alterations in the ratio of these factors during gestation and in complicated pregnancies have been reported; however the impact of this on feto-placental endothelial barrier integrity is unknown. This study investigated the interplay of these factors on junctional occupancy of VE-cadherin and macromolecular leakage in human endothelial monolayers and the perfused placental microvascular bed. Whilst VEGF-A165a (50 ng/ml) increased endothelial monolayer albumin permeability (p0.05) or PlGF (p>0.05) did not. Moreover, VEGF-A165b (100 ng/ml; p0.05) inhibited VEGF-A165a-induced permeability when added singly. PlGF abolished the VEGF-A165b-induced reduction of VEGF-A165a mediated permeability (p>0.05); PlGF was found to compete with VEGF-A165b for binding to Flt-1 at equimolar affinity. Junctional occupancy of VE-cadherin matched alterations in permeability. In the perfused microvascular bed, VEGF-A165b did not induce microvascular leakage but inhibited and reversed VEGF-A165a-induced loss of junctional VE-cadherin and tracer leakage. These results indicate that the anti-angiogenic VEGF-A165b isoform does not increase permeability in human placental microvessels or HUVEC primary cells and can interrupt VEGF-A165a-induced permeability. Moreover, the interplay of these isoforms with PIGF (and s-flt1) suggests that the ratio of these three factors may be important in determining the placental and endothelial barrier in normal and complicated pregnancies

Early Pennsylvanian Odonatoptera from the Xiaheyan locality (Ningxia, China): new material, taxa, and perspectives

Data on Odonatoptera species from the Xiaheyan locality (Ningxia, China; Early Pennsylvanian) described so far are complemented based on abundant new material. Several taxonomic and nomenclatural adjustments are proposed. The species Tupus readi Carpenter, 1933 is transferred to the genus Shenzhousia Zhang & Hong, 2006 in Zhang et al. (2006), and therefore should be referred to as Shenzhousia readi (Carpenter, 1933) n. comb. The monotypic genus Sinomeganeura Ren et al., 2008 is synonymized with Oligotypus Carpenter, 1931. As a consequence the type species of the former must be referred to as Oligotypus huangheensis (Ren et al., 2008) n. comb. The monotypic genus Paragilsonia Zhang, Hong & Su, 2012 in Su et al. (2012) is synonymized with Tupus Sellards, 1906. As a consequence the type-species of the former is to be referred to as Tupus orientalis (Zhang, Hong & Su, 2012 in Su et al. (2012)) n. comb. The monotypic genus Sinierasiptera Zhang, Hong & Su, 2012 in Su et al. (2012) is synonymized with Erasipterella Brauckmann, 1983. As a consequence the type-species of the former is to be referred to as Erasipterella jini (Zhang, Hong & Su, 2012 in Su et al. (2012)) n. comb. In addition Aseripterella sinensis n. gen. et sp. and Sylphalula laliquei n. gen. et sp. are described. The "strong oblique distal" cross-vein, located in the area between RA and RP is found to occur more extensively than previously expected. It is believed to be a structure distinct from the subnodal cross-vein, and therefore deserves to be referred to by a distinct name (viz. "postsubnodal cross-vein"). Odonatoptera from the Xiaheyan locality cover a broad range of sizes. Factors that could have promoted the evolution of large-sized Odonatoptera are briefly reviewed. The permissive conditions prevailing during the Pennsylvanian, and the existence of an elaborated food web, are emphasized as putative positive factors. The new taxonomic treatment suggests that genera documented in the Lower Permian, such as Shenzhousia and Oligotypus, stem from the early Pennsylvanian, and implies a high resilience of these taxa when facing the Pennsylvanian–Permian environmental perturbations. doi:10.1002/mmng.201300006</a

Corrigendum: Early Pennsylvanian Odonatoptera from the Xiaheyan locality (Ningxia, China): new material, taxa, and perspectives

No abstract is available for this article. doi:10.1002/mmng.201390000</a

Comparison of RANS Turbulence Models in Predicting Wake Development in a 2-Dimensional Actuator Disk Model

One of the most popular methodologies used to predict the wake of a tidal stream turbine (TST) is the RANS turbulence models coupled with the actuator disk method. This methodology has been widely adopted in the in the wind industry, since the mid-1990s, to predict wake development of wind turbines. Moreover, the reason for its popularity is its capability to give accurate results at an affordable computational cost, and the application of 2-dimensional actuator disk approach could further reduce the computational cost. In this paper, a number of RANS turbulence models represented by a porous disk were used to simulate the wake development behind a TST, the findings were compared. The models adopted in this work are the Standard k-ε model, the Standard k-ω model, the RNG (Re-Normalised Group) k-ε model, the SST (Shear Stress Transport) k-ω model and the RSM (Reynold Stress Model). The results are also validated against experimental measurements found in literature, with a key focus on comparing the downstream velocity and turbulence intensity. It has shown that the Standard k-ε model is best at predicting downstream wake velocities while the SST k-ω model is better at predicting downstream wake turbulence intensity. Mesh convergence studies were conducted to optimise the computational efficiency for each turbulence model used

ULearn: personalized medical learning on the web for patient empowerment

Health literacy constitutes an important step towards patient empowerment and the Web is presently the biggest repository of medical information and, thus, the biggest medical resource to be used in the learning process. However, at present, web medical information is mainly accessed through generic search engines that do not take into account the user specific needs and starting knowledge and so they are not able to support learning activities tailored to the specific user requirements. This work presents “ULearn” a meta engine that supports access, understanding and learning on the Web in the medical domain based on specific user requirements and knowledge levels towards what we call “balanced learning”. Balanced learning allows users to perform learning activities based on specific user requirements (understanding, deepening, widening and exploring) towards his/her empowerment. We have designed and developed ULearn to suggest search keywords correlated to the different user requirements and we have carried out some preliminary experiments to evaluate the effectiveness of the provided information

Observations of the post shock break-out emission of SN 2011dh with XMM-Newton

After the occurrence of the type cIIb SN 2011dh in the nearby spiral galaxy M 51 numerous observations were performed with different telescopes in various bands ranging from radio to gamma-rays. We analysed the XMM-Newton and Swift observations taken 3 to 30 days after the SN explosion to study the X-ray spectrum of SN 2011dh. We extracted spectra from the XMM-Newton observations, which took place ~7 and 11 days after the SN. In addition, we created integrated Swift/XRT spectra of 3 to 10 days and 11 to 30 days. The spectra are well fitted with a power-law spectrum absorbed with Galactic foreground absorption. In addition, we find a harder spectral component in the first XMM-Newton spectrum taken at t ~ 7 d. This component is also detected in the first Swift spectrum of t = 3 - 10 d. While the persistent power-law component can be explained as inverse Compton emission from radio synchrotron emitting electrons, the harder component is most likely bremsstrahlung emission from the shocked stellar wind. Therefore, the harder X-ray emission that fades away after t ~ 10 d can be interpreted as emission from the shocked circumstellar wind of SN 2011dh.Comment: Accepted for publication as a Research Note in Astronomy and Astrophysic

Cognitive optimism of distinctive initiatives to foster self-directed and self-regulated learning skills:A comparative analysis of conventional and blended-learning in undergraduate studies

Independent learning in massive open online courses (MOOCs) requires considerable effort from the learners themselves. Blended-learning has been recognised to foster independent learning among undergraduate students. With the popularity of the blended-learning approach to teach in traditional educational settings, little has been mentioned on how cohesive this approach is in fostering self-directed learning and self-regulation among university students. This study hopes to explore undergraduate learners in their distinctive study patterns. The study was conducted to investigate a comparative study between students from two departments; Science and Social Science. The aim was to explore the students’ self-directed and self-regulated learning skills in conventional classrooms and aspects of blended-learning embedded in a MOOC platform in two academic years for undergraduates at a top UK university. This study encompasses two case studies; firstly, a combine blended-learning seminar and a conventional seminar classes and a study undertaken with a student of English as a second language (ESL). The blended-learning students were participants who registered in a conventional university and took an optional module in computer security. The second group of students participated in a core module of logic and verification. The second case study was with a final year undergraduate student in Education Studies. The students studied and engaged with the course content using their initiative and directing their learning approaches

Learning analytics for motivating self-regulated learning and fostering the improvement of digital MOOC resources

Nowadays, the digital learning environment has revolutionized the vision of distance learning course delivery and drastically transformed the online educational system. The emergence of MOOCs (Massive Open Online courses) has exposed web technology used in education in a more advanced revolution ushering a new generation of learning environments. The digital learning environment is expected to augment the real world conventional education setting. The educational pedagogy are tailored with the standard practice which has been noticed to increase student success in MOOCs and provide a revolutionary way of self-regulated learning. However, there are still unresolved questions relating to the understanding of learning analytics data and how this could be implemented in educational contexts to support individual learning. One of the major issue in MOOCs is the consistent high dropout rate which over time has seen courses recorded less than 20% completion rate. This paper explores learning analytics from different perspectives in a MOOC context. Firstly, we review existing literature relating to learning analytics in MOOCs, bringing together findings and analyses from several courses. We explore meta-analysis of the basic factors that correlate to learning analytics and the significant in improving education. Secondly, using themes emerging from the previous study, we propose a preliminary model consisting of four factors of learning analytics. Finally, we provide a framework of learning analytics based on the following dimensions: descriptive, diagnostic, predictive and prescriptive, suggesting how the factors could be applied in a MOOC context. Our exploratory framework indicates the need for engaging learners and providing the understanding of how to support and help participants at risk of dropping out of the course