Protective effects of solvent fractions of Mentha spicata (L.) leaves evaluated on 4-nitroquinoline-1-oxide induced chromosome damage and apoptosis in mouse bone marrow cells

Spearmint leaves (Mentha spicata L.) contain high levels of antioxidants that are known to protect against both exogenous and endogenous DNA damage. In this study, the protective effects of the hexane fraction (HF), chloroform fraction (CF) and ethyl acetate fraction (EAF) in an ethanol extract from M. spicata were evaluated against 4-nitroquinoline-1-oxide (4-NQO) induced chromosome damage and apoptosis in bone marrow cells of Swiss albino mice. Two (EAF; 80 and 160 mg/ kg body weight - bw) or three (HF and CF; 80, 160 and 320 mg/ kg bw) doses of solvent fractions or vehicle control (25% DMSO in water) were administered orally for five consecutive days. Upon the sixth day, 4-NQO was injected intraperitoneally. The animals were killed the following day. Other control groups were comprised of animals treated with either the vehicle control or the various doses of solvent fractions, but with no 4-NQO treatment. 4-NQO induced micro-nucleated polychromatic erythrocytes (MnPCEs) in all the test groups. However, pre-treatment of animals with the solvent fractions significantly reduced the 4-NQO-induced MnPCEs as well as the percentage of apoptotic cells. The reduction of both MnPCE and apoptosis was more evident following the pre-treatment of animals with 160 mg/kg bw EAF

Lithocholic Acid Is an Eph-ephrin Ligand Interfering with Eph-kinase Activation

Eph-ephrin system plays a central role in a large variety of human cancers. In fact, alterated expression and/or de-regulated function of Eph-ephrin system promotes tumorigenesis and development of a more aggressive and metastatic tumour phenotype. In particular EphA2 upregulation is correlated with tumour stage and progression and the expression of EphA2 in non-trasformed cells induces malignant transformation and confers tumorigenic potential. Based on these evidences our aim was to identify small molecules able to modulate EphA2-ephrinA1 activity through an ELISA-based binding screening. We identified lithocholic acid (LCA) as a competitive and reversible ligand inhibiting EphA2-ephrinA1 interaction (Ki = 49 µM). Since each ephrin binds many Eph receptors, also LCA does not discriminate between different Eph-ephrin binding suggesting an interaction with a highly conserved region of Eph receptor family. Structurally related bile acids neither inhibited Eph-ephrin binding nor affected Eph phosphorylation. Conversely, LCA inhibited EphA2 phosphorylation induced by ephrinA1-Fc in PC3 and HT29 human prostate and colon adenocarcinoma cell lines (IC50 = 48 and 66 µM, respectively) without affecting cell viability or other receptor tyrosine-kinase (EGFR, VEGFR, IGFR1β, IRKβ) activity. LCA did not inhibit the enzymatic kinase activity of EphA2 at 100 µM (LANCE method) confirming to target the Eph-ephrin protein-protein interaction. Finally, LCA inhibited cell rounding and retraction induced by EphA2 activation in PC3 cells. In conclusion, our findings identified a hit compound useful for the development of molecules targeting ephrin system. Moreover, as ephrin signalling is a key player in the intestinal cell renewal, our work could provide an interesting starting point for further investigations about the role of LCA in the intestinal homeostasis

Analysis of profiles of students applying for entrance to universities

Applicants to universities present profiles of performance in a variety of relevant content areas as evidence for selection. Even though profiles of different applicants may involve different content areas, the applicants may be competing for places to the same university and even to the same program of study. In that case, and if there are more eligible applicants than there are places, universities must reconcile these different profiles in order to make comparisons among them. When there is a small number of applicants, then these comparisons may be camed out qualitatively; when the number of applicants runs into the order of thousands and there is a short time in which to make the offers, some quantitative analysis is required. This quantitative analysis usually involves aggregating the components of each profile in order to form a single score from which comparisons among applicants can be made readily. Legitimate concerns can be raised regarding forming simple aggregates from diverse components of profiles, but despite these concerns, the practical problem of making relatively rapid decisions means that these concerns are generally not addressed. The premise of this article is that profiles will be more or less consistent among the components and that although some profiles may not be, a great number of others may be, summarized adequately by a single score. It is shown that by applying the principles of latent trait test theory at the level of tests, it is possible to rank order a set of profiles in terms of the adequacy with which they are summarized by a single score, and that as a result, only a subset of the original profiles may require a qualitative analysis. The application of the procedure is illustrated with a random sample of 577 profiles from a population of 12,314, which were presented for selection into universities in Western Australia in 1986

Standards-based assessment a tool and means to the development of human capital and capacity building in education

This paper outlines a model for giving meaning to student achievement by referencing assessment to student learning or standards. This effectively shifts the focus in assessment from notions of rank ordering students (comparing their performance purely to each other) to those of monitoring growth or progress and measurement. More specifically it introduces standards-based assessment: the concept and theory. It considers how such systems operate and provides some possible strategies for implementation. Finally it shows how such systems can significantly impact upon human capital and capacity building in education

Measuring attitudes toward plagiarism: issues and psychometric solutions

Purpose - The purpose of this paper is to address the issue of failing to psychometrically test questionnaire instruments when measuring university students\u27 attitudes towards plagiarism. These issues are highlighted by a psychometric evaluation of a commonly used (but previously untested) plagiarism attitudinal scale. Design/methodology/approach - The importance of psychometric testing is shown through an analysis of a commonly used scale using modern techniques (e.g. Rasch analysis) on 131 undergraduate education students at an Australian university. Findings - Psychometric analysis revealed the scale to be unreliable in its present form. However, when reduced to an eight-item subscale it became marginally reliable. Research limitations/implications - The main implication of this paper is that questionnaire instruments cannot be assumed to function as they are intended without thorough psychometric testing. Practical implications - The paper offers valuable insight into the psychometric properties of a previously untested but commonly used plagiarism attitudinal scale. Originality/value - The paper offers a straightforward and easy to understand introduction to researchers in higher education who use questionnaires/surveys in their research but lack an understanding of why psychometric testing is so critical. While similar papers have been written in other fields which advocate psychometric approaches, such as Rasch analysis, this has not been the case in higher educational research (or mainstream educational research for that matter)

Evaluating the validity of the online multiliteracy assessment tool

© 2017, © Australian Council for Educational Research 2017. This study aims to assess the validity of the Online Multiliteracy Assessment for students in Years 5 and 6. The Online Multiliteracy Assessment measures students’ abilities in making and creating meaning, using a variety of different modes of communication, such as text, audio and video. The study involved selecting two groups of students: the first group (n=19) was used in two pilot studies of the items and the second (n=299) was used in a field trial validating the functioning of the items and assessing the quality of the scale. The results indicated that the Online Multiliteracy Assessment has acceptable test–retest reliability; however, the fit to the Rasch model was less than ideal. Further investigation identified two important areas for improvement. First, the items assessing the higher order skills of synthesising, communicating and creating need to be more cognitively demanding. Second, some items need to be modified in order to improve their functionality