Scanning Electron Microscopy of the Pericarp and Testa of Several Sorghum Varieties

Pericarp thickness (determined by Z gene) varies greatly among sorghum varieties ranging· from very thin (8 ~ m) to very thick (160 ~m ) . Pericarp thickness also varies within an individuual kernel. The areas below the style and near the hilum are the thickest with the sides of the kernel being thinnest . Scanning electron microscopy was used to document differences in pericarp thickness and to explain milling differences . Varieties with a thick pericarp had starch granules in the mesocarp cell layers. Sorghums with a thin pericarp did not have starch granules in the mesocarp except near the hilum and stylar area. U.S. sorghum varieties studied had a testa thickness of 16-40 ~m (side of the kernel) but recently four Malian sorghums from a recent collection had very thin testae of 8-16 ~ m. The Sudanese sorghum Shawaya had a testa ranging in thickness from 28-40~m

Characterisation of slip and twin activity using digital image correlation and crystal plasticity finite element simulation:Application to orthorhombic αα-uranium

Calibrating and verifying crystal plasticity material models is a significant challenge, particularly for materials with a number of potential slip and twin systems. Here we use digital image correlation on coarse-grained $\alpha$-uranium during tensile testing in conjunction with crystal plasticity finite element simulations. This approach allows us to determine the critical resolved shear stress, and hardening rate of the different slip and twin systems. The constitutive model is based on dislocation densities as state variables and the simulated geometry is constructed from electron backscatter diffraction images that provide shape, size and orientation of the grains, allowing a direct comparison between virtual and real experiments. An optimisation algorithm is used to find the model parameters that reproduce the evolution of the average strain in each grain as the load is increased. A tensile bar, containing four grains aligned with the load direction, is used to calibrate the model with eight unknown parameters. The approach is then independently validated by simulating the strain distribution in a second tensile bar. Different mechanisms for the hardening of the twin systems are evaluated. The latent hardening of the most active twin system turns out to be determined by coplanar twins and slip. The hardening rate of the most active slip system is lower than in fine-grained $\alpha$-uranium. The method developed in the present research can be applied to identify the critical resolved shear stress and hardening parameters of other coarse-grained materials

Resources and users in the tagging process: approaches and case studies

In this contribution we propose a comparison between two distinct approaches to the annotation of digital resources. The former, top-down, is rooted in the cathedral model and is based on an authoritative, centralized definition of the adopted mark-up language; the latter, bottom-up, refers to the bazaar model and is based on the contributions of a community of users. These two approaches are analyzed taking into account both their descriptive potential and the constraints they impose on the reasoning process of recommender systems, with special reference to user profiling. Three case studies are described, with reference to research projects that apply these approaches in the contexts of e-learning and knowledge management

Electrically Conductive CNT Composites at Loadings below Theoretical Percolation Values

The article of record as published may be found at https://doi.org/10.3390/nano9040491It is well established that dramatic increases in conductivity occur upon the addition of conductive filler materials to highly resistive polymeric matrices in experimental settings. However, the mechanisms responsible for the observed behavior at low filler loadings, below theoretical percolation limits, of even high aspect ratio fillers such as carbon nanotubes (CNT) are not completely understood. In this study, conductive composites were fabricated using CNT bundles dispersed in epoxy resins at diverse loadings, using different dispersion and curing protocols. Based on electron microscopy observation of the CNTs strands distribution in the polymeric matrices and the corresponding electrical conductivities of those specimens, we concluded that no single electron transfer model can accurately explain the conductive behavior for all the loading values. We propose the existence of two different conductive mechanisms; one that exists close to the percolation limit, from ‘low loadings’ to higher CNT contents (CNT % wt > 0.1) and a second for ‘extremely low loadings’, near the percolation threshold (CNT % wt < 0.1). The high conductivity observed for composites at low CNT loading values can be explained by the existence of a percolative CNT network that coexists with micron size regions of non-conductive material. In contrast, samples with extremely low CNT loading values, which present no connectivity or close proximity between CNT bundles, show an electrical conductivity characterized by a current/voltage dependence. Data suggests that at these loadings, conduction may occur via a material breakdown mechanism, similar to dielectric breakdown in a capacitor. The lessons learned from the data gathered in here could guide future experimental research aimed to control the conductivity of CNT composites

Calcium-dependent increase in tyrosine kinase activity stimulated by angiotensin II.

The cellular effects of numerous hormones and neurotransmitters, including the vasoactive agents angiotensin II (AngII) and [Arg8]vasopressin, are mediated in part by protein-serine threonine kinases activated by increase of cytosolic Ca2+ concentration. In this study, we have tested the ability of Ca(2+)-mobilizing agents to activate cellular tyrosine kinases. Treatment of intact GN4 liver epithelial cells with AngII rapidly (less than or equal to 15 sec) increased tyrosine kinase activity measured either in unfractionated cell lysates or in anti-phosphotyrosine immune complexes from detergent-solubilized cells. Increased phosphorylation of the exogenous substrate poly(Glu80Tyr20) (3- to 4-fold over control) by immunoprecipitated kinases closely paralleled the time- and dose-dependence of the appearance of tyrosine phosphoproteins in intact cells. This effect of AngII was mimicked by thapsigargin, a Ca(2+)-elevating tumor promoter. The ability of AngII, but not epidermal growth factor, to increase tyrosine kinase activity was blocked in cells loaded with the Ca2+ chelator bis-(O-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid. Dephosphorylation of immunoprecipitated proteins by tyrosine phosphatase treatment was accompanied by a 60-70% loss in in vitro kinase activity, suggesting that the AngII-sensitive kinase(s) are activated by phosphorylation in intact cells. These findings demonstrate a link between two widely occurring signaling pathways, the tyrosine kinases and the Ca2+ second-messenger system, and suggest the possible involvement of Ca(2+)-activated tyrosine kinases in the endocrine actions of AngII and [Arg8]vasopressin

Interaction between androgen receptor and coregulator SLIRP is regulated by Ack1 tyrosine kinase and androgen

Aberrant activation of the androgen receptor (AR) may play a critical role in castration resistant prostate cancer. After ligand binding, AR is recruited to the androgen responsive element (ARE) sequences on the DNA where AR interaction with coactivators and corepressors modulates transcription. We demonstrated that phosphorylation of AR at Tyr-267 by Ack1/TNK2 tyrosine kinase results in nuclear translocation, DNA binding, and androgen-dependent gene transcription in a low androgen environment. In order to dissect downstream mechanisms, we searched for proteins whose interaction with AR was regulated by Ack1. SLIRP (SRA stem-loop interacting RNA binding protein) was identified as a candidate protein. Interaction between AR and SLIRP was disrupted by Ack1 kinase activity as well as androgen or heregulin treatment. The noncoding RNA, SRA, was required for AR-SLIRP interaction. SLIRP was bound to ARE’s of AR target genes in the absence of androgen. Treatment with androgen or heregulin led to dissociation of SLIRP from the ARE. Whole transcriptome analysis of SLIRP knockdown in androgen responsive LNCaP cells showed that SLIRP affects a significant subset of androgen-regulated genes. Our data suggest that Ack1 kinase and androgen regulate interaction between AR and SLIRP and that SLIRP functions as a coregulator of AR with properties of a corepressor in a context-dependent manner

Required Skills for Teachers: Information Literacy at the Top

European Conference on Information Literacy (ECIL) 2017: Information Literacy in the Workplace, held in Saint Malo, France, 18-21 SeptemberThis study seeks to contribute to a reflection on teachers’ training and professional development in the field of information literacy, in Portugal. Aspects regarding teacher training and their role as spreaders of knowledge and multipliers of good practices are problematized. UNESCO’s curriculum for teachers and ACRL guidelines are used methodologically as the central thread of this interpretation. From here we seek to explain how a higher education institution – an Institute of Education -, which is devoted to the professional development of educators, including teachers, has engaged in information literacy actions through training interventions, in recent years. The study concludes that through sharing and dialogue within the librarian profession, but also within the sphere of education professionals - teachers and trainers - the best training practices in university libraries can be consolidated. Finally, certain points for reflection and debate concerning this theme are proposed.info:eu-repo/semantics/publishedVersio

Library not found: The disconnect between gaming research and development

Video games clearly have great educational potential, both for formal and informal learning, and this avenue is being thoroughly investigated in the psychology and education literature. However, there appears to be a disconnect between social science academic research and the game development sector, in that research and development practices rarely inform each other. This paper presents a two-part analysis of this communicative disconnect based on investigations carried out within the H2020 Gaming Horizons project. The first part regards a literature review that identified the main topics of focus in the social sciences literature on games, as well as the chief recommendations authors express. The second part examines 73 interviews with 30 developers, 14 researchers, 13 players, 12 educators, and 4 policy makers, investigating how they perceived games and gaming. The study highlights several factors contributing to the disconnect: different priorities and dissemination practices; the lag between innovation in the games market and research advancements; low accessibility of academic research; and disproportionate academic focus on serious games compared to entertainment games. The authors suggest closer contact between researchers and developers might be sought by diversifying academic dissemination channels, promoting conferences involving both groups, and developing research partnerships with entertainment game companies

Educational games as a motivational tool: Considerations on their potential and limitations

There is considerable interest in leveraging video games to support students’ motivation. This involves employment of educational (serious) and entertainment games. However, while evidence indicates that games can enhance learning outcomes, doubts persist about whether they retain their enjoyable character in formal learning contexts. This study was carried out within the H2020 Gaming Horizons project, which involved a review of academic literature on the role of games in society, as well as 73 semi-structured interviews with relevant stakeholders, including players and educators, investigating their positions on game-related issues. The interviews suggested that players tend to view game-based learning – and specifically serious games at school – with scepticism. This is partly attributable to the perception that serious games have lower production values than entertainment games, and that gaming, as a voluntary, self-driven activity, clashes with the structured nature of school. Some educators reported individual and gender differences in the motivating power of games. However, the use of entertainment games to foster learning outcomes was seen favourably. Two focus groups devoted to the issue highlighted the need for carefully tailoring the gaming experience to both context and student, and the importance of developing a sustainable business model for enhancing serious games quality

Oncology providers' perspectives on endocrine therapy prescribing and management.

Adjuvant endocrine therapy (ET) can reduce the risk of recurrence among females with hormone receptor-positive breast cancer. Overall, initiation and adherence to ET are suboptimal, though reasons are not well described. The study's objective was to better understand ET decision making, prescribing, and patient management from oncology providers' perspectives. Using purposive sampling, we recruited oncology providers who saw five or more breast cancer patients per week (n=20). We conducted 30-45-minute telephone interviews, using a semistructured guide to elicit perspectives on ET use. We used thematic content analysis to systematically identify categories of meaning and double-coded transcripts using Atlas.ti. Providers recommend ET to all eligible patients except those with contraindications or other risk factors. Providers base their ET prescribing decisions on the patient's menopausal status, side effects, and comorbidities. ET is typically discussed multiple times: at the onset of breast cancer treatment and in more detail after other treatment completion. Providers felt that the associated recurrence risk reduction is the most compelling argument for patients during ET decision making. While providers rarely perceived noninitiation as a problem, nonadherence was prevalent, often due to unresolvable side effects. From the clinicians' perspectives, side effects from ET are the dominant factor in nonadherence. Efforts to improve adherence should focus on strategies to minimize side effects and ensure clinicians and patients are well informed regarding optimal side effect management. This finding has important implications for novel endocrine regimens that offer improved outcomes through longer duration or more intensive therapy