Two common nonsynonymous paraoxonase 1 (PON1) gene polymorphisms and brain astrocytoma and meningioma

<p>Abstract</p> <p>Background</p> <p>Human serum paraoxonase 1 (PON1) plays a major role in the metabolism of several organophosphorus compounds. The enzyme is encoded by the polymorphic gene <it>PON1</it>, located on chromosome 7q21.3. Aiming to identify genetic variations related to the risk of developing brain tumors, we investigated the putative association between common nonsynonymous <it>PON1 </it>polymorphisms and the risk of developing astrocytoma and meningioma.</p> <p>Methods</p> <p>Seventy one consecutive patients with brain tumors (43 with astrocytoma grade II/III and 28 with meningioma) with ages ranging 21 to 76 years, and 220 healthy controls subjects were analyzed for the frequency of the nonsynonymous <it>PON1 </it>genotypes L55M rs854560 and Q192R rs662. All participants were adult Caucasian individuals recruited in the central area of Spain.</p> <p>Results</p> <p>The frequencies of the <it>PON1 </it>genotypes and allelic variants of the polymorphisms <it>PON1 </it>L55M and <it>PON1 </it>Q192R did not differ significantly between patients with astrocytoma and meningioma and controls. The minor allele frequencies were as follows: <it>PON1 </it>55L, 0.398, 0.328 and 0.286 for patients with astrocytoma, meningioma and control individuals, respectively; <it>PON1 </it>192R, 0.341, 0.362 and 0.302 for patients with astrocytoma, meningioma and control individuals, respectively. Correction for age, gender, or education, made no difference in odds ratios and the <it>p </it>values remained non-significant. Haplotype association analyses did not identify any significant association with the risk of developing astrocytoma or meningioma.</p> <p>Conclusions</p> <p>Common nonsynonymous <it>PON1 </it>polymorphisms are not related with the risk of developing astrocytoma and meningioma.</p

Investigating students' interest in chemistry through self-generated questions

This study investigates Turkish students' (age 15 or older) interest in chemistry by analysing 1027 of their self-generated chemistry-related questions, which had been submitted to a popular science magazine. These questions were classified based on the field of interest, the cognitive level of the question, and the stimulating impetus for asking the question. In addition, gender-related patterns were noted in these three categories. Those results demonstrated that males asked overwhelmingly more questions than females in an informal setting. In general, students mostly asked questions about "states of matter and solutions" and "nuclear chemistry and chemistry of the elements." Most of the students asked for the properties of a variable and sought to learn about factual and explanatory types of information. The driving factors that led students to ask questions were mostly non-applicative stimulus. Significant differences emerged in some categories. For example, while males were more interested in comparison and causal relationships, females were more interested in specific information about properties. Moreover, while males tended toward seeking methodological information, making predictions, asking open-ended questions, and making general requests for information, females were more interested than males in factual and explanatory types of information. The implications of students' self-generated chemistry questions for science curriculum reform and teaching are discussed in this paper. © the Partner Organisations 2014

methanol oxidation

Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. In this study, we report the synthesis of metallic and bimetallic nanoparticle (AgNP, AuNP, and Ag@AuNP)-involved l-cysteine-functionalized reduced graphene oxide nanocomposite (AgNPs/cis/rGO, AuNPs/cis/rGO, and Ag@Au/cis/rGO) and their applications as an electrocatalyst for methanol electro-oxidation. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Experimental results demonstrated that the prepared nanocomposites enhanced electrochemical efficiency for methanol electro-oxidation with regard to diffusion efficiency, oxidation potential, and forward oxidation peak current

The nature and development of interaction among components of pedagogical content knowledge in practicum

This secondary analysis study focused on how interactions among preservice teachers' pedagogical content knowledge (PCK) components developed throughout a 14-week CoRe-based mentoring-enriched practicum course, and the nature of those interactions. Data were collected from three preservice teachers, information-rich cases, by the use of content representation (CoRe) and semi-structured interviews. Content analysis and the constant comparative method were employed in the data analysis. Results revealed that the development of integrations was idiosyncratic. Additionally, PCK integration moved from fragmented to a more integrated and coherent one by the end of the semester. Implications for science teacher education and research are discussed. •When necessary support is provided, preservice teachers are able to develop PCK.•The development in the interplay among PCK components was idiosyncratic.•PCK interaction can be nourished through mentoring in preservice teacher education. © 2014 Elsevier Ltd

Providing a set of research-based practices to support preservice teachers' long-term professional development as learners of science teaching

The purpose of this research was twofold. The first was to investigate the development of preservice teachers' knowledge base for science teaching on the rate of reaction topic within the 14-week content representation (CoRe)-based mentoring-enriched practicum course. In this course, CoRe design was used as a form of lesson planning and intensive educative mentoring was provided by teaching assistants. The second purpose was to identify which aspects of the practicum course contributed to preservice teachers' development. Three preservice chemistry teachers voluntarily participated in the study. Qualitative data sources included CoRe, semistructured interviews, and reflection papers. Both inductive and deductive analyses were applied by triangulating findings from multiple data sources. Results revealed that at the end of the practicum, participants were able to successfully link content with teaching to promote student learning. Their pedagogical content knowledge (PCK) developed with its all components coherently integrated with each other. They also started to view the PCK construct as professional pedagogical knowledge. Educative mentoring with the use of an explicit and shared PCK language supported by CoRes, teaching experiences, and the observation of peers were reported as the most valuable aspects in stimulating teacher development. Implications for teachers' professional growth and research are discussed. © 2013 Wiley Periodicals, Inc