The Zr–Sn binary system: New experimental results and thermodynamic assessment

The Zr–Sn binary system has been reinvestigated by several experimental techniques: X-ray diffraction, electron probe micro-analysis, mass density and calorimetry measurements. The existence of a miscibility gap inside the homogeneity domain of the phase (Zr5Sn3–Zr5Sn4) has been confirmed. It has been also shown that Zr substitution on the Sn sublattice is responsible for the non-stoichiometry of the A15 phase (Zr4Sn). The temperature of the peritectoid reaction Zr+A15 $ Zr has been determined to be at 1216 K that is 40 below the temperature reported in the literature. All these new experimental data have been taken into account for a new thermodynamic assessment of this system

Effect of fire on the palatability of plants in an African woodland savanna: varying impacts depending on plant functional groups

Fire and herbivores are two important drivers of changes in vegetation composition, quality and dynamics and both are highly related to each other. Herbivores are known to respond to fire both in terms of foraging decisions and distribution. However, little is known about the actual changes in plant chemistry following a fire event and how long these changes will last. We investigated the effect of fire on two different plant functional groups (grasses and woody species) in a woodland savanna of southern Africa. We studied chemical compounds known to be important for palatability of five perennial grass and seven woody species (trees and shrubs) common in the woodland savanna and known to be utilized by herbivores. We wanted to know if plant chemistry differs between a recently burned site (burned 2 years ago) and a control site, burned 16 years ago, and if grasses and woody species show similar relative differences between sites (i.e., the plants' response to fire). We found a clear difference in chemical composition patterns between the plant functional groups, with an almost homogenous response to fire among woody species, but higher variability in response among grass species. Furthermore, we found that woody species maintained a higher nutritional value even 2 years after burning, whereas grasses did not show clear differences among the two investigated sites. Hence, few years after burning, woody plants might still serve as an attraction for herbivores, especially browsers, in contrast to grasses. The knowledge about these differences between the two functional groups in response to fire is beneficial for the development of management strategies for large herbivores whether domestic or wild

Self-reflective practices during teaching and learning of an undergraduate literacy module

This paper is based on a field experience project designed as part of the foundation phase literacy programme. In this project, foundation phase teacher education student-teachers selected a teaching site and a learner or group of learners that they would teach to read in the afternoons and over the weekends. The aim of the project was to offer the teacher education student-teachers an opportunity to put theory into practice using self-reflective strategies that included group and individual reflections on instructional strategies presented in DVDs, reflections on microteaching lessons to the class, and reflections on teaching learners in local schools. During the time that they were working with their learners, they were also expected to confer with other teacher education student-teachers to exchange ideas, strategies and their „best practice‟ experiences with others. Three distinct stages emerged as student-teachers taught and reflected on their experiences. Student-teachers were initially unsure of their capability of taking on the project. The second stage was that of determination to grapple with the project and the last stage was resolving to take ownership of the project. This paper recommends that projects of this nature are necessary as they allow undergraduate student-teachers opportunities for authentic learning regarding the teaching of reading.http://www.krepublishers.comhb201

Anxiety in Mice: A Principal Component Analysis Study

Two principal component analyses of anxiety were undertaken investigating two strains of mice (ABP/Le and C57BL/6ByJ) in two different experiments, both classical tests for assessing anxiety in rodents. The elevated plus-maze and staircase were used for the first experiment, and a free exploratory paradigm and light-dark discrimination were used for the second. The components in the analyses produced definitions of four fundamental behavior patterns: novelty-induced anxiety, general activity, exploratory behavior, and decision making. We also noted that the anxious phenotype was determined by both strain and experimental procedure. The relationship between behavior patterns and the use of specific tests plus links with the genetic background are discussed

Pregnane × Receptor (PXR) expression in colorectal cancer cells restricts irinotecan chemosensitivity through enhanced SN-38 glucuronidation

<p>Abstract</p> <p>Background</p> <p>Clinical efficacy of chemotherapy in colorectal cancer is subjected to broad inter-individual variations leading to the inability to predict outcome and toxicity. The topoisomerase I inhibitor irinotecan (CPT-11) is worldwide approved for the treatment of metastatic colorectal cancer and undergoes extensive peripheral and tumoral metabolism. PXR is a xenoreceptor activated by many drugs and environmental compounds regulating the expression of drug metabolism and transport genes in detoxification organs such as liver and gastrointestinal tract. Considering the metabolic pathway of irinotecan and the tissue distribution of Pregnane × Receptor (PXR), we hypothesized that PXR could play a key role in colon cancer cell response to irinotecan.</p> <p>Results</p> <p>PXR mRNA expression was quantified by RT-quantitative PCR in a panel of 14 colon tumor samples and their matched normal tissues. PXR expression was modulated in human colorectal cancer cells LS174T, SW480 and SW620 by transfection and siRNA strategies. Cellular response to irinotecan and its active metabolic SN38 was assessed by cell viability assays, HPLC metabolic profiles and mRNA quantification of PXR target genes. We showed that PXR was strongly expressed in colon tumor samples and displayed a great variability of expression. Expression of hPXR in human colorectal cancer cells led to a marked chemoresistance to the active metabolite SN38 correlated with PXR expression level. Metabolic profiles of SN38 showed a strong enhancement of SN38 glucuronidation to the inactive SN38G metabolite in PXR-expressing cells, correlated with an increase of UDPglucuronosyl transferases UGT1A1, UGT1A9 and UGT1A10 mRNAs. Inhibition of PXR expression by lentivirus-mediated shRNA, led to SN38 chemoresistance reversion concomitantly to a decrease of UGT1A1 expression and SN38 glucuronidation. Similarly, PXR mRNA expression levels correlated to UGT1A subfamily expression in human colon tumor biopsies.</p> <p>Conclusion</p> <p>Our results demonstrate that tumoral metabolism of SN38 is affected by PXR and point to potential therapeutic significance of PXR quantification in the prediction of irinotecan response. Furthermore, our observations are pharmacologically relevant since many patients suffering from cancer diseases are often exposed to co-medications, food additives or herbal supplements able to activate PXR. A substantial part of the variability observed among patients might be caused by such interactions</p

Education for democratic citizenship through a literacy-based approach : a case of South African township children

The study contextualises the position of child citizens in the South African democracy and highlights how education for democratic citizenship is employed through a literacy-based approach. The qualitative study was exploratory and based on a lesson presented to nine-year-old township children by giving them language-related tasks. Through the children’s voices we present the life experiences that expressed their need for basic services, education, extra facilities and security. We argue that children need to experience the benefits of democracy and education for democratic citizenship to build and sustain a resilient democratic society.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1099-0860hj201

Teaching reading comprehension to Grade 3 Tshivenda-speaking learners

The main objective of the study was to explore how teachers teach reading comprehension to Grade 3 Tshivenda-speaking learners. This qualitative study was prompted by the low levels of reading amongst these Grades 3 learners in South Africa. Three schools, each with two Grade 3 classes, were selected in this study. Data from individual interviews with teachers, focus group interviews and classroom observations revealed that there were a number of factors that contributed to the Grade 3 learners‟ poor performance in reading comprehension. It is recommended that teacher education programmes should be improved and that Tshivenda reading resources be made available, as these are currently extremely limited. The study also indicated that the best way to teach reading comprehension is by teaching learners a variety of strategies that they can use in order to self-regulate their comprehension when reading.http://journals.co.za/content/journal/jedsam2017Early Childhood Educatio

Teachers’ perceptions and value of Yoruba as a medium of instruction in primary 3 classes

Yoruba is one of the languages recognised in Nigeria to be used as medium of instruction in the lower primary classes as stipulated by the Nigerian National Policy on Education. This study investigated how teachers experience the use of Yoruba as medium of instruction in primary classes. The study was qualitative thus employed the one-on-one interview schedule, semi- structured observation schedule and document analysis as data collection instruments. The participants included 10 primary three teachers in two primary schools. The findings revealed amongst others that despite lack of support from the government teachers have taken it upon themselves to promote Yoruba and make it accessible to learners. The study recommended that the government should do more to provide workshops and relevant materials for teaching.http://www.krepublishers.com/02-Journals/IJES/IJES-00-0-000-000-2009-Web/IJES-00-0-000-000-2009-1-Cover.htmhb201

Reference gene selection for head and neck squamous cell carcinoma gene expression studies

<p>Abstract</p> <p>Background</p> <p>It is no longer adequate to choose reference genes blindly. We present the first study that defines the suitability of 12 reference genes commonly used in cancer studies (<it>ACT, ALAS, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPL27, RPS29, SHAD </it>and <it>TBP</it>) for the normalization of quantitative expression data in the field of head and neck squamous cell carcinoma (HNSCC).</p> <p>Results</p> <p>Raw expression levels were measured by RT-qPCR in HNSCC and normal matched mucosa of 46 patients. We analyzed the expression stability using geNorm and NormFinder and compared the expression levels between subgroups. In HNSCC and/or normal mucosa, the four best normalization genes were <it>ALAS, GAPDH, RPS18 </it>and <it>SHAD </it>and the most stable combination of two genes was <it>GAPDH-SHAD</it>. We recommend using <it>KALPHA-TBP </it>for the study of T1-T2 tumors, <it>RPL27-SHAD </it>for T3-T4 tumors, <it>KALPHA-SHAD </it>for N0 tumors, and <it>ALAS-TBP </it>for N+ tumors. <it>ACT, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPS29, SHAD </it>and <it>TBP </it>were slightly misregulated (<1.7-fold) between tumor and normal mucosa but can be used for normalization, depending on the resolution required for the assay.</p> <p>Conclusion</p> <p>In the field of HNSCC, this study will guide researchers in selecting the most appropriate reference genes from among 12 potentially suitable reference genes, depending on the specific setting of their experiments.</p

Quelle articulation entre les pôles de compétitivité et les tissus productifs régionaux ?: Une mise en perspective de quatre pôles en Provence-Alpes-Côte d'Azur

L'objectif de ce travail de recherche était de mettre en lumière les conditions de mise en œuvre et les bénéfices attendus de quatre pôles de compétitivité de la région PACA (Solutions communicantes sécurisées ; Mer, sécurité et sûreté, Développement durable ; Fruits et légumes ; Parfums, arômes, senteurs, saveurs). Le questionnement e a été décliné suivant deux axes : 1/ quelle est la capacité réelle de ces dispositifs à produire, diffuser et utiliser des ressources scientifiques et techniques ? Les pôles de compétitivité ont en charge de produire de nouvelles ressources dans des tissus productifs préexistants. Comment s'articulent ces nouvelles ressources avec celles déjà existantes ? Sont-elles susceptibles de se féconder mutuellement ? Mais dans le même temps, n'y a-t-il pas des risques de polarisation de l'activité et de ce fait, des risques d'exclusion ? 2/ quelle est la capacité réelle du nouveau dispositif à susciter et installer durablement la coopération nécessaire à la création des ressources attendues