The Prospects of Radical Change Today

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Slavoj Žižek

2018-05-01

Full Text Available In this contribution, Slavoj Žižek takes the occasion of Marx’s bicentenary for reflecting on the prospects of radical change today. First, it is shown that under Stalinism, Lenin’s works were quoted out of context in an arbitrary way in order to legitimise arbitrary political measures. Marxism thereby became an ideology that justified brutal subjective interventions. Second, this contribution poses the question of the revolutionary subject and democracy today. It stresses the role of both contingency and strategy in revolutions. In political assemblages taking place on public squares, the inert mass of ordinary people is transubstantiated into a politically engaged united force. The basic political problem today is how to best reconfigure democracy. Third, this contribution analyses the “interesting times” we live in. These are times that feature multiple crises, right-wing populism à la Donald Trump and Marine Le Pen, the lower classes’ opposition to immigration, and the refugee crisis. Questions about human rights and their violation and about radical change need to be asked in this context.

To master or perform? Exploring relations between achievement goals and conceptual change learning.

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Ranellucci, John; Muis, Krista R; Duffy, Melissa; Wang, Xihui; Sampasivam, Lavanya; Franco, Gina M

2013-09-01

Research is needed to explore conceptual change in relation to achievement goal orientations and depth of processing. To address this need, we examined relations between achievement goals, use of deep versus shallow processing strategies, and conceptual change learning using a think-aloud protocol. Seventy-three undergraduate students were assessed on their prior knowledge and misconceptions about Newtonian mechanics, and then reported their achievement goals and participated in think-aloud protocols while reading Newtonian physics texts. A mastery-approach goal orientation positively predicted deep processing strategies, shallow processing strategies, and conceptual change. In contrast, a performance-approach goal orientation did not predict either of the processing strategies, but negatively predicted conceptual change. A performance-avoidance goal orientation negatively predicted deep processing strategies and conceptual change. Moreover, deep and shallow processing strategies positively predicted conceptual change as well as recall. Finally, both deep and shallow processing strategies mediated relations between mastery-approach goals and conceptual change. Results provide some support for Dole and Sinatra's (1998) Cognitive Reconstruction of Knowledge Model of conceptual change but also challenge specific facets with regard to the role of depth of processing in conceptual change. © 2012 The British Psychological Society.

Conceptual Teaching Based on Scientific Storyline Method and Conceptual Change Texts: Latitude-Parallel Concepts

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Uzunöz, Abdulkadir

2018-01-01

The purpose of this study is to identify the conceptual mistakes frequently encountered in teaching geography such as latitude-parallel concepts, and to prepare conceptual change text based on the Scientific Storyline Method, in order to resolve the identified misconceptions. In this study, the special case method, which is one of the qualitative…

Conceptual Model of Climate Change Impacts at LANL

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Dewart, Jean Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-17

Goal 9 of the LANL FY15 Site Sustainability Plan (LANL 2014a) addresses Climate Change Adaptation. As part of Goal 9, the plan reviews many of the individual programs the Laboratory has initiated over the past 20 years to address climate change impacts to LANL (e.g. Wildland Fire Management Plan, Forest Management Plan, etc.). However, at that time, LANL did not yet have a comprehensive approach to climate change adaptation. To fill this gap, the FY15 Work Plan for the LANL Long Term Strategy for Environmental Stewardship and Sustainability (LANL 2015) included a goal of (1) establishing a comprehensive conceptual model of climate change impacts at LANL and (2) establishing specific climate change indices to measure climate change and impacts at Los Alamos. Establishing a conceptual model of climate change impacts will demonstrate that the Laboratory is addressing climate change impacts in a comprehensive manner. This paper fulfills the requirement of goal 1. The establishment of specific indices of climate change at Los Alamos (goal 2), will improve our ability to determine climate change vulnerabilities and assess risk. Future work will include prioritizing risks, evaluating options/technologies/costs, and where appropriate, taking actions. To develop a comprehensive conceptual model of climate change impacts, we selected the framework provided in the National Oceanic and Atmospheric Administration (NOAA) Climate Resilience Toolkit (http://toolkit.climate.gov/).

Learning in Different Modes: The Interaction Between Incremental and Radical Change

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Petersen, Anders Hedegaard; Boer, Harry; Gertsen, Frank

2004-01-01

The objective of the study presented in this article is to contribute to the development of theory on continuous innovation, i.e. the combination of operationally effective exploitation and strategically flexible exploration. A longitudinal case study is presented of the interaction between...... incremental and radical change in Danish company, observed through the lens of organizational learning. The radical change process is described in five phases, each of which had its own effects on incremental change initiatives in the company. The research identified four factors explaining these effects, all...

Facilitating conceptual change in students’ understanding of concepts related to pressure

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Ozkan, Gulbin; Sezgin Selcuk, Gamze

2016-09-01

The aim of this research was to explore the effects of three different types of methods of learning physics (conceptual change-based, real life context-based and traditional learning) on high school physics students in the 11th grade in terms of conceptual change they achieved in learning about the various topics (pressure exerted by solids, pressure in stagnant liquids and gases, buoyancy, Bernoulli’s principle). In this study, a pre-test/post-test quasi-experimental method with nonequivalent control group, involving a 3 (group) × 2 (time) factorial design was used. Study group 1 were given the conceptual change texts on the mentioned subjects, study group 2 were offered a teaching approach based on real life context-based learning, whereas the control group was taught in the traditional style. Data for the research were collected with the ‘pressure conceptual test’. As a result of research, the number of misconceptions had been reduced or shifted altogether in all three groups. After the instruction, it was seen that none of the students formed new misconceptions. It was found that the most positive change could be seen in the conceptual change text group followed by context-based and lastly traditional. The fact that none of the students formed new misconceptions is important, particularly since research such as the following shows that conceptual change is tenuous and inconsistent, taking time to shift in a sustained manner.

A conceptual change analysis of nature of science conceptions: The deep roots and entangled vines of a conceptual ecology

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Johnston, Adam Thomas

This research used theories of conceptual change to analyze learners' understandings of the nature of science (NOS). Ideas regarding the NOS have been advocated as vital aspects of science literacy, yet learners at many levels (students and teachers) have difficulty in understanding these aspects in the way that science literacy reforms advocate. Although previous research has shown the inadequacies in learners' NOS understandings and have documented ways by which to improve some of these understandings, little has been done to show how these ideas develop and why learners' preexisting conceptions of NOS are so resistant to conceptual change. The premise of this study, then, was to describe the nature of NOS conceptions and of the conceptual change process itself by deeply analyzing the conceptions of individual learners. Toward this end, 4 individuals enrolled in a physical science course designed for preservice elementary teachers were selected to participate in a qualitative research study. These individuals answered questionnaires, surveys, direct interview questions, and a variety of interview probes (e.g., critical incidents, responses to readings/videos, reflections on coursework, card sorting tasks, etc.) which were administered throughout the duration of a semester. By utilizing these in-depth, qualitative probes, learners' conceptions were not only assessed but also described in great detail, revealing the source of their conceptions as well as identifying many instances in which a learner's directly stated conception was contradictory to that which was reflected by more indirect probes. As a result of this research, implications regarding NOS conceptions and their development have been described. In addition, various descriptions of conceptual change have been further refined and informed. Especially notable, the influence of a learner's conceptual ecology and its extrarational influences on conceptual change have been highlighted. It is argued that

Radical abundance how a revolution in nanotechnology will change civilization

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Drexler, K Eric

2013-01-01

K. Eric Drexler is the founding father of nanotechnology--the science of engineering on a molecular level. In Radical Abundance, he shows how rapid scientific progress is about to change our world. Thanks to atomically precise manufacturing, we will soon have the power to produce radically more of what people want, and at a lower cost. The result will shake the very foundations of our economy and environment. Already, scientists have constructed prototypes for circuit boards built of millions of precisely arranged atoms. The advent of this kind of atomic precision promises to change the way we make things--cleanly, inexpensively, and on a global scale. It allows us to imagine a world where solar arrays cost no more than cardboard and aluminum foil, and laptops cost about the same. A provocative tour of cutting edge science and its implications by the field's founder and master, Radical Abundance offers a mind-expanding vision of a world hurtling toward an unexpected future.

High school student's motivation to engage in conceptual change-learning in science

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Barlia, Lily

1999-11-01

This study investigated motivational factors that are related to engaging in conceptual change learning. While previous studies have recognized the resistance of students' scientific conception to change, few have investigated the role that non-cognitive factors might play when students are exposed to conceptual change instruction. Three research questions were examined: (a) What instructional strategies did the teacher use to both promote students' learning for conceptual change and increase their motivation in learning science? (b) What are the patterns of students' motivation to engage in conceptual change learning? And (c) what individual profiles can be constructed from the four motivational factors (i.e., goals, values, self-efficacy, and control beliefs) and how are these profiles linked to engagement (i.e., behavioral and cognitive engagement) in conceptual change learning of science? Eleven twelfth grade students (senior students) and the teacher in which conceptual change approach to teaching was used in daily activities were selected. Data collection for this study included student's self-reported responses to the Motivated Strategies for Learning Questionnaire (MSLQ), classroom observation of students and the teacher, and structured interviews. Analysis of these data resulted in a motivational factor profile for each student and cross case analysis for entire group. Results from this study indicate that each student has different motivation factors that are mostly influenced individual student to learn science. Among these motivation factors, task value and control beliefs were most important for students. The implication of these findings are that teachers need to encourage students to find learning for conceptual change a valuable task, and that students need to find applications for their new conceptions within their everyday lives. In addition, teachers need to encourage students to develop learning strategies for conceptual understanding

Radical clashes : what tangible interaction is made of

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Dijk, van J.; Mousette, C.; Kuenen, C.D.; Hummels, C.C.M.

2013-01-01

Driven by a critique of Ishii et al's recent vision of Radical Atoms we call for a debate on the different conceptual paradigms underlying the TEI community and its activities. TEI was initiated to share and connect different perspectives, but we feel conceptual debate is lacking. To fuel this

The Conceptual Change Approach to Teaching Chemical Equilibrium

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Canpolat, Nurtac; Pinarbasi, Tacettin; Bayrakceken, Samih; Geban, Omer

2006-01-01

This study investigates the effect of a conceptual change approach over traditional instruction on students' understanding of chemical equilibrium concepts (e.g. dynamic nature of equilibrium, definition of equilibrium constant, heterogeneous equilibrium, qualitative interpreting of equilibrium constant, changing the reaction conditions). This…

Deciphering free-radical code of radiation effects

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Volovyk, S.; Bazyka, D.; Loganovsky, K.; Bebeshko, V.

2007-01-01

Complete text of publication follows. Objective: Ionizing radiation is fundamental environmental factor for life origin and evolution. Free radicals, primordial 'sea' for life conceiving and existence, induced by cosmic and terrestrial background radiation, are evolutionally archetypal, ubiquitous, and omnipotent in physiological- pathophysiological dichotomy. Classical free-radical paradigm in radiation biology and medicine, focused in essence on oxidative damage, needs new conceptualization and generalization. Methods: Suggested novel insights into free radicals dual immanent nature and functions in organism systems are based on original concepts of radicals dynamic charge transfer (CT) - redox ambivalence (interactional nucleo-, electro-, and ambiphilicity spectrum); pertinent chemical reactivity and selectivity delocalization model; physiological functional ambivalence and complementarity, and dynamic free-radical homeostasis. Results: Subtle perturbations in radicals CT spatiotemporal homeodynamics, in responsive signaling / controlling networks, concomitant alterations in genes expression, transcription, and apoptosis, redox control of mitochondrial ET chain, telomere/telomerase balance, DNA CT, circadian clock, hemispheric biochemical dominance/accentuation, including alteration of nitric oxide-superoxide complementarity, membranes permeability, neurotransmission pattern, synaptic circuitry, etc under radiation exposure have more fundamental impact on organism systems (especially CNS and CVS) deterioration than simple radicals inflicted oxidative (nitrosative) damage of cellular constituents. Conclusions: This novel conceptualization of free-radical paradigm constitutes new dimension in deciphering molecular mechanisms of radiation effects on subtle borderline norm-pathology and continuity-discontinuity dichotomy in organisms systems disorders - CT(redox)omics, which involves investigation of CT, redox, and spin states of free radicals, DNA bases

Conceptual Change within Dyadic Interactions: The Dance of Conceptual and Material Agency

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Heyd-Metzuyanim, Einat; Schwarz, Baruch B.

2017-01-01

We offer a new approach to emergent knowledge in processes of conceptual change in dyadic interaction by drawing on Pickering's ("The Mangle of Practice," The University of Chicago Press, London, 1995) Mangle of Practice theory, which theorizes the emergence of new scientific knowledge as occurring due to material resistance and human…

Conceptualizing Learning in the Climate Justice Movement

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Kluttz, Jenalee; Walter, Pierre

2018-01-01

This article extends Scandrett et al.'s conceptual framework for social movement learning to understand learning and knowledge creation in the climate justice movement. Drawing on radical pluralist theoretical approaches to social movement learning, learning in the climate justice movement is conceptualized at the micro, meso, and macro levels,…

Conceptual and epistemological undercurrents of learning as a process of change

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Montfort, Devlin B.

2011-12-01

In the preparation and education of civil engineers it is essential to both increase student knowledge of the world (conceptual understanding), but also to establish and develop new ways of thinking (epistemology). Both of these processes of change can be considered learning, but they are vastly different in the time, energy and resources they require to accomplish. The second type of learning (conceptual change) is more difficult, and is only rarely accomplished in traditional university education. The purpose of this research is to apply existing research approaches from cognitive science and educational psychology to explain why by investigating conceptual change in the contexts of student learning and faculty adoption of new pedagogies. In each context, the difficulty with conceptual change was associated with the ways in which people categorize fundamental phenomena in the world around them, and with epistemological expectations of how those categorizations should be applied in new contexts. While attempts to encourage change often focus on "educating" people by providing them with more knowledge, the change processes seem to be primarily limited by people's existing knowledge and how it is structured. Because civil engineers interact closely with societal goals and processes (such as human safety and environmental policies), they adopt epistemological stances that are as-yet unaccounted for in most research on the subject, which assumes a strong distinction between epistemological stances toward the physical world compared to the social world. These differences suggest that civil engineers' conceptual change could be enhanced by more directly addressing their particular epistemological stances---which incorporate high needs for certainty in guaranteeing human safety, as well as high flexibility when being applied to human systems.

CONCEPTUAL DESIGN FOR A RADICALLY SMALLER, HIGHLY ADAPTIVE AND APPLICATION-FLEXIBLE MINING MACHINE FOR UTILITY AND DEVELOPMENT WORK

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Andrew H. Stern

2004-12-20

The aim of this research project was to develop a preliminary ''conceptual design'' for a radically smaller, highly adaptive and application-flexible underground coal mining machine, for performing non-production utility work and/or also undertake limited production mining for the recovery of reserves that would otherwise be lost. Whereas historically, mining philosophies have reflected a shift to increasing larger mechanized systems [such as the continuous miner (CM)], specific mining operations that do not benefit from the economy of the large mining equipment are often ignored or addressed with significant inefficiencies. Developing this prototype concept will create a new class of equipment that can provide opportunities to re-think the very structure of the mining system across a broad range of possibilities, not able to be met by existing machinery. The approach involved pooling the collective input from mining professionals, using a structured listing of desired inputs in the form of a questionnaire, which was used to define the range of desired design specifications. From these inputs, a conceptual specification was blended, by the author, to embody the general concurrence of mission concepts for this machine.

Conceptual Change in Elementary School Teacher Candidate Knowledge of Rock-Cycle Processes.

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Stofflett, Rene Therese

1994-01-01

Investigates the knowledge of elementary school teacher candidates on rock-cycle processes. Three different instructional interventions were used to improve their knowledge: (1) conceptual-change teaching; (2) traditional didactic teaching; and (3) microteaching. The conceptual-change group showed the most growth in understanding, supporting…

Changing our minds: a commentary on `Conceptual change: a discussion of theoretical, methodological and practical challenges for science education'

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Mercer, Neil

2008-07-01

This paper begins with a consideration of some important themes dealt with in the paper by Treagust and Duit. These include the relationship between research on conceptual change and educational practice, the significance of emotion and identity in the process of conceptual change, and role of cognitive conflict in motivating change. I then argue that the authors implicitly assert the importance of spoken dialogue as a motor for conceptual change, but do not give it the proper, explicit recognition that it deserves. I first use their own data of transcribed talk to make this point, and then go on to elaborate my case by drawing on other research. Talk amongst students and teacher-student talk are both considered. My conclusion is that while more empirical research is needed to understand how dialogue is involved in conceptual change, available evidence shows very clearly that the role of talk and social interaction is so significant that it cannot be ignored. It is therefore necessary for theoretical accounts to deal with both social (i.e. communicative) and cognitive aspects of conceptual change.

Facilitating Students' Conceptual Change and Scientific Reasoning Involving the Unit of Combustion

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Lee, Chin-Quen; She, Hsiao-Ching

2010-01-01

This article reports research from a 3 year digital learning project to unite conceptual change and scientific reasoning in the learning unit of combustion. One group of students had completed the course combining conceptual change and scientific reasoning. The other group of students received conventional instruction. In addition to the…

Conceptual foundations of quantum mechanics

International Nuclear Information System (INIS)

Shimony, A.

1989-01-01

Radical innovation in the quantum mechanical framework such as objective indefiniteness, objective chance, objective probability, potentiality, entanglement and quantum nonlocality are discussed and related to the standard formalism. Examples are given which though problematic in classical mechanics are simply explained with these new concepts. Evidence is presented that the conceptual innovations of quantum mechanics cannot be separated from its predictive power. Proposals for solving ''the reduction of the wave packet'' anomaly are presented. Further radical innovations in quantum mechanics are anticipated. (U.K.)

The Use of Conceptual Change Text toward Students’ Argumentation Skills in Learning Sound

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Sari, B. P.; Feranie, S.; Winarno, N.

2017-09-01

This research aim is to investigate the effect of Conceptual Change Text toward students’ argumentation skills in learning sound concept. The participant comes from one of International school in Bandung, Indonesia. The method that used in this research is a quasi-experimental design with one control group (N=21) and one experimental group (N=21) were involves in this research. The learning model that used in both classes is demonstration model which included teacher explanation and examples, the difference only in teaching materials. In experiment group learn with Conceptual Change Text, while control group learn with conventional book which is used in school. The results showed that Conceptual Change Text instruction was better than the conventional book to improved students’ argumentation skills of sound concept. Based on this results showed that Conceptual Change Text instruction can be an alternative tool to improve students’ argumentation skills significantly.

The Role of Cognitive, Metacognitive, and Motivational Variables in Conceptual Change: Preservice Early Childhood Teachers' Conceptual Understanding of the Cause of Lunar Phases

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Sackes, Mesut

2010-01-01

This study seeks to explore and describe the role of cognitive, metacognitive, and motivational variables in conceptual change. More specifically, the purposes of the study were (1) to investigate the predictive ability of a learning model that was developed based on the intentional conceptual change perspective in predicting change in conceptual…

Experiencing conceptual change about teaching: A case study from astronomy

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Bailey, Janelle M.; Nagamine, Kentaro

2012-06-01

Understanding faculty motivations for and barriers to change is an important component of facilitating instructional reform efforts to improve student learning. This case study describes the process of adoption of learner-centered instructional strategies by an astronomy faculty member, Ken, as viewed through the lens of conceptual change. Specifically, we applied the Cognitive Reconstruction of Knowledge Model (CRKM) to understand why Ken was willing to change his instructional strategies, what barriers to and supports for change existed, and how he and his students were impacted by this change. Ken's statements and actions represented characteristics consistent with the CRKM. Notably, dissatisfaction, considered the primary motivator in many conceptual change models, was not of high importance in this case. Upon implementing learner-centered strategies, Ken's students performed better on a measure of knowledge about stellar properties, which served to reinforce his motivation to continue with learner-centered methods.

Examining young children's conceptual change process in floating and sinking from a social constructivist perspective

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Havu-Nuutinen, Sari

2005-03-01

This paper presents a case study of the process of conceptual change in six-year-old children. The process of conceptual change in learning about floating and sinking is described from two different viewpoints: how the children's conceptions change during the instructional process, and how the social discussion during the experimental exploration can be seen in terms of the cognitive changes in the children. Based on qualitative analysis of verbal data, changes in the children's conceptions were mostly epistemological and the children's theories of flotation became more complete with respect to the scientific view. From the viewpoint of the conceptual change, conceptually orientated teacher-child interactions seemed to support the children's cognitive progress in cognitive skills and guided the children to consider the reasons for the flotation.

Misconceptions in Electricity and Conceptual Change Strategy

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Yunus Karakuyu

2011-12-01

Full Text Available This research is about the contribution of conceptual change texts in accompanying with the concept mapping instruction to tenth-grade students‟ understanding of electricity concepts, and their retention of this understanding. Electricity concepts test are improved as a result of interview with teachers who observe students problems and literature search about this topic. The test was applied as pre-test, post-test, and delayed post-test total of 66 tenth-grade students in two classes of the same high school in center of Afyonkarahisar, taught by the same teacher. Electricity is the subject of tenth-grade according to the new secondary physics program. The experimental group was 32 students who received conceptual change texts in accompanying with concept mapping instruction in a class. The control group was a class of 34 students who received traditional instruction. In this study besides practice, previous information and the ability of logical thinking formed the other independent variations. Conclusions show that logical thinking, treatment and previous knowledge about concepts of electricity make a major contribution on students‟ understanding of these concepts. Result shows that in terms of keeping in mind, concept change texts in accompanying with concept map teaching better than traditional education

To Master or Perform? Exploring Relations between Achievement Goals and Conceptual Change Learning

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Ranellucci, John; Muis, Krista R.; Duffy, Melissa; Wang, Xihui; Sampasivam, Lavanya; Franco, Gina M.

2013-01-01

Background: Research is needed to explore conceptual change in relation to achievement goal orientations and depth of processing. Aims: To address this need, we examined relations between achievement goals, use of deep versus shallow processing strategies, and conceptual change learning using a think-aloud protocol. Sample and Method:…

The impact of CmapTools utilization towards students' conceptual change on optics topic

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Rofiuddin, Muhammad Rifqi; Feranie, Selly

2017-05-01

Science teachers need to help students identify their prior ideas and modify them based on scientific knowledge. This process is called as conceptual change. One of essential tools to analyze students' conceptual change is by using concept map. Concept Maps are graphical representations of knowledge that are comprised of concepts and the relationships between them. Constructing concept map is implemented by adapting the role of technology to support learning process, as it is suitable with Educational Ministry Regulation No.68 year 2013. Institute for Human and Machine Cognition (IHMC) has developed CmapTools, a client-server software for easily construct and visualize concept maps. This research aims to investigate secondary students' conceptual change after experiencing five-stage conceptual teaching model by utilizing CmapTools in learning Optics. Weak experimental method through one group pretest-posttest design is implemented in this study to collect preliminary and post concept map as qualitative data. Sample was taken purposively of 8th grade students (n= 22) at one of private schools Bandung, West Java. Conceptual change based on comparison of preliminary and post concept map construction is assessed based on rubric of concept map scoring and structure. Results shows significance conceptual change differences at 50.92 % that is elaborated into concept map element such as prepositions and hierarchical level in high category, cross links in medium category and specific examples in low category. All of the results are supported with the students' positive response towards CmapTools utilization that indicates improvement of motivation, interest, and behavior aspect towards Physics lesson.

Supplier's involvement and success of radical new product development in new ventures

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Song, Michael; Di Benedetto, Anthony

2008-01-01

Supplier involvement is essential to a new venture seeking to develop a radical innovation. Despite this, prior literature has not adequately addressed supplier involvement in radical innovation, nor what the antecedents to increased supplier involvement are. We build and test a conceptual model of

Profiles of inconsistent knowledge in children's pathways of conceptual change.

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Schneider, Michael; Hardy, Ilonca

2013-09-01

Conceptual change requires learners to restructure parts of their conceptual knowledge base. Prior research has identified the fragmentation and the integration of knowledge as 2 important component processes of knowledge restructuring but remains unclear as to their relative importance and the time of their occurrence during development. Previous studies mostly were based on the categorization of answers in interview studies and led to mixed empirical results, suggesting that methodological improvements might be helpful. We assessed 161 third-graders' knowledge about floating and sinking of objects in liquids at 3 measurement points by means of multiple-choice tests. The tests assessed how strongly the children agreed with commonly found but mutually incompatible statements about floating and sinking. A latent profile transition analysis of the test scores revealed 5 profiles, some of which indicated the coexistence of inconsistent pieces of knowledge in learners. The majority of students (63%) were on 1 of 7 developmental pathways between these profiles. Thus, a child's knowledge profile at a point in time can be used to predict further development. The degree of knowledge integration decreased on some individual developmental paths, increased on others, and remained stable on still others. The study demonstrates the usefulness of explicit quantitative models of conceptual change. The results support a constructivist perspective on conceptual development, in which developmental changes of a learner's knowledge base result from idiosyncratic, yet systematic knowledge-construction processes. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Re-Conceptualizing Adult Education's Monolithic Behaviourist Interpretation: Toward a New Understanding of Radical Behaviourism

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Roessger, Kevin M.

2012-01-01

The philosophy of radical behaviourism remains misunderstood within the field of adult education. Contributing to this trend is the field's homogeneous behaviourist interpretation, which attributes methodological behaviourism's principles to radical behaviourism. The guiding principles and assumptions of radical behaviourism are examined to…

Conceptual Change regarding middle school students' experience with Global Climate Change

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Golden, B. W.; Lutz, B.

2011-12-01

Given the complexity of the science involving climate change (IPCC, 2007), its lack of curricular focus within US K-12 schooling (Golden, 2009), and the difficulty in effecting conceptual change in science (Vosniadou, 2007), we sought to research middle school students' conceptions about climate change, in addition to how those conceptions changed during and as a result of a deliberately designed global climate change (GCC) unit. In a sixth grade classroom, a unit was designed which incorporated Argumentation-Driven Inquiry (Sampson & Grooms, 2010). That is, students were assigned to groups and asked to make sense of standard GCC data such as paleoclimate data from ice cores, direct temperature measurement, and Keeling curves, in addition to learning about the greenhouse effect in a modeling lesson (Hocking, et al, 1993). The students were then challenged, in groups, to create, on whiteboards, explanations and defend these explanations to and with their peers. They did two iterations of this argumentation. The first iteration focused on the simple identification of climate change patterns. The second focused on developing causal explanations for those patterns. After two rounds of such argumentation, the students were then asked to write (individually) a "final" argument which accounted for the given data. Interview and written data were analyzed prior to the given unit, during it, and after it, in order to capture complicated nuance that might escape detection by simpler research means such as surveys. Several findings emerged which promised to be of interest to climate change educators. The first is that many students tended to "know" many "facts" about climate change, but were unable to connect these disparate facts in any meaningful ways. A second finding is that while no students changed their entire belief systems, even after a robust unit which would seemingly challenge such, each student engaged did indeed modify the manner in which they discussed the

Middle School Students' Conceptual Change in Global Climate Change: Using Argumentation to Foster Knowledge Construction

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Golden, Barry W.

2011-01-01

This research examined middle school student conceptions about global climate change (GCC) and the change these conceptions undergo during an argument driven instructional unit. The theoretical framework invoked for this study is the "framework theory" of conceptual change (Vosniadou, 2007a). This theory posits that students do not…

Future Elementary School Teachers' Conceptual Change Concerning Photosynthesis

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Ahopelto, Ilona; Mikkila-Erdmann, Mirjamaija; Anto, Erkki; Penttinen, Marjaana

2011-01-01

The purpose of this study was to examine conceptual change among future elementary school teachers while studying a scientific text concerning photosynthesis. Students' learning goals in relation to their learning outcomes were also examined. The participants were future elementary school teachers. The design consisted of pre- and post-tests. The…

The role of organizational structure in readiness for change: A conceptual integration.

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Benzer, Justin K; Charns, Martin P; Hamdan, Sami; Afable, Melissa

2017-02-01

The purpose of this review is to extend extant conceptualizations of readiness for change as an individual-level phenomenon. This review-of-reviews focuses on existing conceptual frameworks from the dissemination, implementation, quality improvement, and organizational transformation literatures in order to integrate theoretical rationales for how organization structure, a key dimension of the organizational context, may impact readiness for change. We propose that the organization structure dimensions of differentiation and integration impact readiness for change at the individual level of analysis by influencing four key concepts of relevance, legitimacy, perceived need for change, and resource allocation. We identify future research directions that focus on these four key concepts.

The role of accounting practices in a radical change process : towards a comprehensive change framework

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Meer-Kooistra, Jeltje van der

2001-01-01

This paper is concerned with investigating the role of accounting practices in radical change processes. The institutional framework has been taken as a starting point in investigating these processes. The research has been carried out at the Dutch Railways. This company was forced by the Dutch

Bureaucratic Activism and Radical School Change in Tamil Nadu, India

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Niesz, Tricia; Krishnamurthy, Ramchandar

2013-01-01

In 2007, Activity Based Learning (ABL), a child-centered, activity-based method of pedagogical practice, transformed classrooms in all of the over 37,000 primary-level government schools in Tamil Nadu, India. The large scale, rapid pace, and radical nature of educational change sets the ABL initiative apart from most school reform efforts.…

Effectiveness of Conceptual Change Texts: A Meta Analysis

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Armagan, Fulya Öner; Keskin, Melike Özer; Akin, Beril Salman

2017-01-01

The purpose of this study was to determine the overall effectiveness of conceptual change texts (CCTs) on academic achievement and to find out if effectiveness was related to some characteristics of the study. It followed up a Meta-analysis research approach. 42 published and unpublished studies, published between 1995 and 2010, and 42 experiment…

El decadentismo en la derecha radical contemporánea

Directory of Open Access Journals (Sweden)

Miguel Ángel Simón Gómez

2007-07-01

Full Text Available The main concern this articles deals with is, first, the elusive conceptual definition of the «radical right». In the last years a, so called, new consensus, has been developed in the literature of this field. The core of this new consensus about the radical right is the palingentic form of nationalism, form this pant of view the decadentism and the claim for a social renewal is a central point in the political thought of the radical right. In this article we deal with the decadent subjects of the radical right, pointing mainly to the apocalyptic tone of some major contributors of the radical right in the interwar France and Germany. In the second part we analyze the role of decadentism in the cotemporary work of some relevant authors of the European radical right, Alain de Benoist and Julius Evola. Finally we translate their idea of decadence of Europe to the political arena as shown the discourses of some right extremist European parties.

Diversity Management Change Projects: In Need of Alternative Conceptual Approaches?

Directory of Open Access Journals (Sweden)

Christina Evans

2012-09-01

Full Text Available Drawing on a meta-analysis of an evaluation of a European Social Fund project aimed at enhancing employment opportunities for women in Information Technology, Electronic and Computing (ITEC, this paper critically debates how effectual a diversity management approach alone is as an underpinning rationale for change in the complex area of diversity. The paper draws on the experiences of ‘partner organizations’, gathered through interviews conducted during the evaluation stage of the project. The paper discusses some of the tensions experienced by partner organizations, thus providing new insights into why such projects are not as effectual as they might be. The paper concludes by presenting a case for the need to re-conceptualise how change as part of a wider diversity management approach might best be conceptualized. We suggest that a ‘systems approach’ could prove a more fruitful way of conceptualizing change of this nature given the inter-dependences between different organizations and institutions.

ERP implementation: an integrated process of radical change and continuous learning

DEFF Research Database (Denmark)

Kræmmergaard, Pernille; Møller, Charles; Boer, Harry

2003-01-01

This paper seeks to develop management theory that can be used to increase the likelihood of ERP implementation success. The paper argues and demonstrates that an ERP implementation can be understood as an intended radical change that can be managed to some extent. But during the use of the syste...

Conceptual Change in Understanding the Nature of Science Learning: An Interpretive Phenomenological Analysis

Science.gov (United States)

DiBenedetto, Christina M.

This study is the first of its kind to explore the thoughts, beliefs, attitudes and values of secondary educators as they experience conceptual change in their understanding of the nature of science learning vis a vis the Framework for K-12 Science Education published by the National Research Council. The study takes aim at the existing gap between the vision for science learning as an active process of inquiry and current pedagogical practices in K-12 science classrooms. For students to understand and explain everyday science ideas and succeed in science studies and careers, the means by which they learn science must change. Focusing on this change, the study explores the significance of educator attitudes, beliefs and values to science learning through interpretive phenomenological analysis around the central question, "In what ways do educators understand and articulate attitudes and beliefs toward the nature of science learning?" The study further explores the questions, "How do educators experience changes in their understanding of the nature of science learning?" and "How do educators believe these changes influence their pedagogical practice?" Study findings converge on four conceptions that science learning: is the action of inquiry; is a visible process initiated by both teacher and learner; values student voice and changing conceptions is science learning. These findings have implications for the primacy of educator beliefs, attitudes and values in reform efforts, science teacher leadership and the explicit instruction of both Nature of Science and conceptual change in educator preparation programs. This study supports the understanding that the nature of science learning is cognitive and affective conceptual change. Keywords: conceptual change, educator attitudes and beliefs, framework for K-12 science education, interpretive phenomenological analysis, nature of science learning, next generation science standards, science professional development

Climate Change Conceptual Change: Scientific Information Can Transform Attitudes.

Science.gov (United States)

Ranney, Michael Andrew; Clark, Dav

2016-01-01

Of this article's seven experiments, the first five demonstrate that virtually no Americans know the basic global warming mechanism. Fortunately, Experiments 2-5 found that 2-45 min of physical-chemical climate instruction durably increased such understandings. This mechanistic learning, or merely receiving seven highly germane statistical facts (Experiment 6), also increased climate-change acceptance-across the liberal-conservative spectrum. However, Experiment 7's misleading statistics decreased such acceptance (and dramatically, knowledge-confidence). These readily available attitudinal and conceptual changes through scientific information disconfirm what we term "stasis theory"--which some researchers and many laypeople varyingly maintain. Stasis theory subsumes the claim that informing people (particularly Americans) about climate science may be largely futile or even counterproductive--a view that appears historically naïve, suffers from range restrictions (e.g., near-zero mechanistic knowledge), and/or misinterprets some polarization and (noncausal) correlational data. Our studies evidenced no polarizations. Finally, we introduce HowGlobalWarmingWorks.org--a website designed to directly enhance public "climate-change cognition." Copyright © 2016 Cognitive Science Society, Inc.

Autonomy and Emotion Management. Middle managers in welfare professions during radical organizational change

Directory of Open Access Journals (Sweden)

Hulda Mjöll Gunnarsdóttir

2016-03-01

Full Text Available This case study was conducted among middle managers during a period of radical change within the Norwegian child welfare service. Our goal was to explore how the middle managers handle and respond to emotional dissonance and constraints in autonomy during the change process. We collected data through group meetings, individual interviews, and focus groups. Prior research on middle managers has shown their importance in the implementation of organizational change. We propose that middle managers conduct emotion work, emotional labor, and emotional balancing in response to the increased complexity of organizational expectations during change processes. Further, we argue that the need for relevant emotion management reflects a threat to managers’ autonomy. Our findings indicate that middle managers feel emotional dissonance, due to their position as both recipients and executers of organizational change. This makes them vulnerable to questions of loyalty, and they feel they have no backstage where they can express themselves openly. However, their ability to plan emotion management and to balance various conflicting expectations enables them to maintain autonomy during a radical change process. Our basic arguments and findings are summarized by applying the logic of a historistic functional model.

How Hume's Philosophy Informed Radical Behaviorism.

Science.gov (United States)

Nuzzolilli, Andrew E; Diller, James W

2015-05-01

The present paper analyzes consistencies between the philosophical systems of David Hume and B. F. Skinner, focusing on their conceptualization of causality and attitudes about scientific behavior. The ideas that Hume initially advanced were further developed in Skinner's writings and shaped the behavior-analytic approach to scientific behavior. Tracing Skinner's logical antecedents allows for additional historical and philosophical clarity when examining the development of radical behaviorism.

Efficient Multidisciplinary Analysis Approach for Conceptual Design of Aircraft with Large Shape Change

Science.gov (United States)

Chwalowski, Pawel; Samareh, Jamshid A.; Horta, Lucas G.; Piatak, David J.; McGowan, Anna-Maria R.

2009-01-01

The conceptual and preliminary design processes for aircraft with large shape changes are generally difficult and time-consuming, and the processes are often customized for a specific shape change concept to streamline the vehicle design effort. Accordingly, several existing reports show excellent results of assessing a particular shape change concept or perturbations of a concept. The goal of the current effort was to develop a multidisciplinary analysis tool and process that would enable an aircraft designer to assess several very different morphing concepts early in the design phase and yet obtain second-order performance results so that design decisions can be made with better confidence. The approach uses an efficient parametric model formulation that allows automatic model generation for systems undergoing radical shape changes as a function of aerodynamic parameters, geometry parameters, and shape change parameters. In contrast to other more self-contained approaches, the approach utilizes off-the-shelf analysis modules to reduce development time and to make it accessible to many users. Because the analysis is loosely coupled, discipline modules like a multibody code can be easily swapped for other modules with similar capabilities. One of the advantages of this loosely coupled system is the ability to use the medium- to high-fidelity tools early in the design stages when the information can significantly influence and improve overall vehicle design. Data transfer among the analysis modules are based on an accurate and automated general purpose data transfer tool. In general, setup time for the integrated system presented in this paper is 2-4 days for simple shape change concepts and 1-2 weeks for more mechanically complicated concepts. Some of the key elements briefly described in the paper include parametric model development, aerodynamic database generation, multibody analysis, and the required software modules as well as examples for a telescoping wing

Conceptions and Characterization: An Explanation for the Theory-Practice Gap in Conceptual Change Theory. (Sponsored Session Strand 1 Science Learning, Understanding and Conceptual Change)

NARCIS (Netherlands)

Eijck, van M.W.; Czermak, Charlene M.; Duschl, Richard A.; Kyle, William C.; Sondergeld, Toni

2009-01-01

The theory building on conceptual change has led to the paradox that, in order to address teaching-learning processes, research yields an increasingly sophisticated output which alienates the teachers. The aim of this study is to explain the origin of this paradox. Drawing on exemplary data from a

Effects of Computer-Assisted Instruction with Conceptual Change Texts on Removing the Misconceptions of Radioactivity

Directory of Open Access Journals (Sweden)

Ahmet YUMUŞAK

2016-12-01

Full Text Available Training young scientists, enabling conceptual understanding in science education is quite important. Misconception is one of the important indications for whether the concepts are understood or not. The most important educational tools to remove misconceptions are conceptual change texts. In addition, one of the important methods to remove misconceptions is computer-assisted instruction. The goal of this study is to research the effects of the use of computer-assisted instruction (CAI, conceptual change texts (CCT, computer-assisted instruction with conceptual change texts (CAI+CCT, and use of traditional teaching method (TTM on removing the misconceptions of science teacher candidates on the subject of radioactivity. Research sample was made of totally 92 students studying at four different groups of senior students in Celal Bayar University, Faculty of Education, Department of Science Education in 2011-2012 academic year. A different teaching method was used in each group. Experimental groups were randomly determined; in the first experimental group, computer-assisted instruction was used (23 students; in the second experimental group, conceptual change texts were used (23 students; in the third experimental group, computer-assisted instruction with conceptual change texts were used (23 students; and the fourth group, on which traditional education method was used, was called control group (23 students. Two-tier misconception diagnostic instrument, which was developed by the researcher, was used as data collection tool of the research. “Nonequivalent Control Groups Experimental Design” was used in this research in order to determine the efficiency of different teaching methods. Obtained data were analyzed by using SPSS 21.0. As a result of the research, it was determined that methods used on experimental groups were more successful than traditional teaching method practiced on control group in terms of removing misconceptions on

Measuring Conceptual Change on Stoichiometry Using Mental Models and IllStructured Problems In a Flipped Classroom Environment

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Norrie E. Gayeta

2017-05-01

Full Text Available This study aimed to measure conceptual change on stoichiometry using mental models and ill-structured problems in flipped classroom environment. This study examined the level of conceptual understanding of students on stoichiometry before and after exposure to flipped and traditional lecture method. It also covered the type of conceptual change, and students’ description in flipped classroom environment. Qualitative and quantitative research methods were used in the study. Respondents were two sections of third year Bachelor of Secondary Education, Biological Science. Frequency, percentage, ranking, mean, standard deviation, Hake factor test, and t-test were the statistical tools applied to answer specific questions. Results showed profound increase towards conceptual change representing a shift from intuitive understanding to correct incomplete understanding level. Thus, change for the better, in theoretical type was determined from pretest to posttest of students exposed to flipped and traditional instruction. Results also indicated that there is no significant difference on students’ conceptual change on stoichiometry exposed to flipped and traditional lecture method. Furthermore, students strongly agreed that flipped classroom instruction helped them develop positive attitude towards chemistry and appropriate for learning college chemistry.

Learners' strategies for reconstructing cognitive frameworks and navigating conceptual change from prior conception to consensual genetics knowledge

Science.gov (United States)

Parrott, Annette M.

Problem. Science teachers are charged with preparing students to become scientifically literate individuals. Teachers are given curriculum that specifies the knowledge that students should come away with; however, they are not necessarily aware of the knowledge with which the student arrives or how best to help them navigate between the two knowledge states. Educators must be aware, not only of where their students are conceptually, but how their students move from their prior knowledge and naive theories, to scientifically acceptable theories. The understanding of how students navigate this course has the potential to revolutionize educational practices. Methods. This study explored how five 9th grade biology students reconstructed their cognitive frameworks and navigated conceptual change from prior conception to consensual genetics knowledge. The research questions investigated were: (1) how do students in the process of changing their naive science theories to accepted science theories describe their journey from prior knowledge to current conception, and (2) what are the methods that students utilize to bridge the gap between alternate and consensual science conceptions to effect conceptual change. Qualitative and quantitative methods were employed to gather and analyze the data. In depth, semi-structured interviews formed the primary data for probing the context and details of students' conceptual change experience. Primary interview data was coded by thematic analysis. Results and discussion. This study revealed information about students' perceived roles in learning, the role of articulation in the conceptual change process, and ways in which a community of learners aids conceptual change. It was ascertained that students see their role in learning primarily as repeating information until they could add that information to their knowledge. Students are more likely to consider challenges to their conceptual frameworks and be more motivated to become active

Correcting Misconceptions on Electronics: Effects of a Simulation-Based Learning Environment Backed by a Conceptual Change Model

Science.gov (United States)

Chen, Yu-Lung; Pan, Pei-Rong; Sung, Yao-Ting; Chang, Kuo-En

2013-01-01

Computer simulation has significant potential as a supplementary tool for effective conceptual-change learning based on the integration of technology and appropriate instructional strategies. This study elucidates misconceptions in learning on diodes and constructs a conceptual-change learning system that incorporates…

Autonomy and Emotion Management. Middle managers in welfare professions during radical organizational change

OpenAIRE

Hulda Mjöll Gunnarsdóttir

2016-01-01

This case study was conducted among middle managers during a period of radical change within the Norwegian child welfare service. Our goal was to explore how the middle managers handle and respond to emotional dissonance and constraints in autonomy during the change process. We collected data through group meetings, individual interviews, and focus groups. Prior research on middle managers has shown their importance in the implementation of organizational change. We propose that middle manage...

Working Examples (WEx): A Vehicle for Building Radical Innovations to Change Education

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Zywica, Jolene; Roberts, Anna; Davidson, Drew

2013-01-01

Working Examples (WEx) is described by the authors as a vehicle for ideating and building radical innovations to change education. It is a community of researchers, designers, and educators working at the intersection of education and technology. "Examples" (ideas, work, and projects) allow people to explore new ideas, learn from each…

Promoting Conceptual Change in First Year Students' Understanding of Evaporation

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Costu, Bayram; Ayas, Alipasa; Niaz, Mansoor

2010-01-01

We constructed the PDEODE (Predict-Discuss-Explain-Observe-Discuss-Explain) teaching strategy, a variant of the classical POE (Predict-Observe-Explain) activity, to promote conceptual change, and investigated its effectiveness on student understanding of the evaporation concept. The sample consisted of 52 first year students in a primary science…

What Can Be Learned From a Laboratory Model of Conceptual Change? Descriptive Findings and Methodological Issues

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Ohlsson, Stellan; Cosejo, David G.

2014-07-01

The problem of how people process novel and unexpected information— deep learning (Ohlsson in Deep learning: how the mind overrides experience. Cambridge University Press, New York, 2011)—is central to several fields of research, including creativity, belief revision, and conceptual change. Researchers have not converged on a single theory for conceptual change, nor has any one theory been decisively falsified. One contributing reason is the difficulty of collecting informative data in this field. We propose that the commonly used methodologies of historical analysis, classroom interventions, and developmental studies, although indispensible, can be supplemented with studies of laboratory models of conceptual change. We introduce re- categorization, an experimental paradigm in which learners transition from one definition of a categorical concept to another, incompatible definition of the same concept, a simple form of conceptual change. We describe a re-categorization experiment, report some descriptive findings pertaining to the effects of category complexity, the temporal unfolding of learning, and the nature of the learner's final knowledge state. We end with a brief discussion of ways in which the re-categorization model can be improved.

How do Small Groups Promote Behaviour Change? An Integrative Conceptual Review of Explanatory Mechanisms.

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Borek, Aleksandra J; Abraham, Charles

2018-03-01

Small groups are used to promote health, well-being, and personal change by altering members' perceptions, beliefs, expectations, and behaviour patterns. An extensive cross-disciplinary literature has articulated and tested theories explaining how such groups develop, function, and facilitate change. Yet these theoretical understandings are rarely applied in the development, description, and evaluation of health-promotion, group-based, behaviour-change interventions. Medline database, library catalogues, search engines, specific journals and reference lists were searched for relevant texts. Texts were reviewed for explanatory concepts or theories describing change processes in groups, which were integrated into the developing conceptual structure. This was designed to be a parsimonious conceptual framework that could be applied to design and delivery. Five categories of interacting processes and concepts were identified and defined: (1) group development processes, (2) dynamic group processes, (3) social change processes, (4) personal change processes, and (5) group design and operating parameters. Each of these categories encompasses a variety of theorised mechanisms explaining individual change in small groups. The final conceptual model, together with the design issues and practical recommendations derived from it, provides a practical basis for linking research and theory explaining group functioning to optimal design of group-based, behaviour-change interventions. © 2018 The Authors. Applied Psychology: Health and Well-Being published by John Wiley & Sons Ltd on behalf of International Association of Applied Psychology.

The Effect of a Conceptual Change Approach on Understanding of Students' Chemical Equilibrium Concepts

Science.gov (United States)

Atasoy, Basri; Akkus, Huseyin; Kadayifci, Hakki

2009-01-01

The purpose of this study was to compare the effects of a conceptual change approach over traditional instruction on tenth-grade students' conceptual achievement in understanding chemical equilibrium. The study was conducted in two classes of the same teacher with participation of a total of 44 tenth-grade students. In this study, a…

Multiple free-radical scavenging capacity in serum

Science.gov (United States)

Oowada, Shigeru; Endo, Nobuyuki; Kameya, Hiromi; Shimmei, Masashi; Kotake, Yashige

2012-01-01

We have developed a method to determine serum scavenging-capacity profile against multiple free radical species, namely hydroxyl radical, superoxide radical, alkoxyl radical, alkylperoxyl radical, alkyl radical, and singlet oxygen. This method was applied to a cohort of chronic kidney disease patients. Each free radical species was produced with a common experimental procedure; i.e., uv/visible-light photolysis of free-radical precursor/sensitizer. The decrease in free-radical concentration by the presence of serum was quantified with electron spin resonance spin trapping method, from which the scavenging capacity was calculated. There was a significant capacity change in the disease group (n = 45) as compared with the healthy control group (n = 30). The percent values of disease’s scavenging capacity with respect to control group indicated statistically significant differences in all free-radical species except alkylperoxyl radical, i.e., hydroxyl radical, 73 ± 12% (p = 0.001); superoxide radical, 158 ± 50% (p = 0.001); alkoxyl radical, 121 ± 30% (p = 0.005); alkylperoxyl radical, 123 ± 32% (p>0.1); alkyl radical, 26 ± 14% (p = 0.001); and singlet oxygen, 57 ± 18% (p = 0.001). The scavenging capacity profile was illustrated using a radar chart, clearly demonstrating the characteristic change in the disease group. Although the cause of the scavenging capacity change by the disease state is not completely understood, the profile of multiple radical scavenging capacities may become a useful diagnostic tool. PMID:22962529

Using a Conceptual-Change Approach to Help Preservice Science Teachers Reorganize Their Knowledge Structures for Constructivist Teaching

Science.gov (United States)

Dhindsa, H. S.; Anderson, O. R.

2004-02-01

This study, based on constructivist learning theory, examined how effectively preservice chemistry teachers (N = 43) can be educated to think flexibly and to reorganize their thinking in a way that may complement diverse ways students approach the subject domain. The teacher's cognitive structure was assessed prior to and after a conceptual change intervention using flow-map narrative analyses. There was a significant change in the organization of the preservice teacher's narrative after the conceptual change intervention, including greater networking of ideas and more thematic development of the content. Hence, a conceptual change approach may be a useful way to educate teachers to be more responsive to student individual differences when planning and delivering science lessons.

Adam Smith, Market and Social Change

DEFF Research Database (Denmark)

Bouchet, Dominique

2017-01-01

Adam Smith (1723-1790) provided us with a remarkable synthesis of the economic and political ideas of his time and developed a conceptual system to analyse social interactions that mattered for the wealth of nations. He proposed a radically different roadmap for the future development of the soci......Adam Smith (1723-1790) provided us with a remarkable synthesis of the economic and political ideas of his time and developed a conceptual system to analyse social interactions that mattered for the wealth of nations. He proposed a radically different roadmap for the future development...... of the society he lived in. The fact that his original analyses were rooted in a given historical context and were founded on a well thought-through conceptual system should not be ignored. The galvanising effect of the dribs and drabs of Adam Smith ideas that have been bandied about are a long way from...... the powerful insights imbued in the original ideas. Putting those back into context, looking into how Smith proceeded then, trying to update his observations, might help us to be more attentive to the market changes and social challenges of our times....

Knowledgeable Learning and Conceptual Change: Value Adding to Teacher Training

Science.gov (United States)

Yeigh, Tony

2013-01-01

This report concerns the use of pre and post responses to an online questionnaire as evidence of knowledgeable learning by education students at a regional Australian university. Factor analysis was used to reveal conceptual changes in the students' thinking about classroom management across a unit of learning they had undertaken. These changes…

Cognitive Conflict and Situational Interest as Factors Influencing Conceptual Change

Science.gov (United States)

Kang, Hunsik; Scharmann, Lawrence C.; Kang, Sukjin; Noh, Taehee

2010-01-01

In this study, we investigated the relationships among cognitive conflict and situational interest induced by a discrepant event, attention and effort allocated to learning, and conceptual change in learning the concept of density. Subjects were 183 seventh graders from six middle schools in Seoul, Korea. A preconception test, a test of responses…

Process Improvement in a Radically Changing Organization

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Varga, Denise M.; Wilson, Barbara M.

2007-01-01

This presentation describes how the NASA Glenn Research Center planned and implemented a process improvement effort in response to a radically changing environment. As a result of a presidential decision to redefine the Agency's mission, many ongoing projects were canceled and future workload would be awarded based on relevance to the Exploration Initiative. NASA imposed a new Procedural Requirements standard on all future software development, and the Center needed to redesign its processes from CMM Level 2 objectives to meet the new standard and position itself for CMMI. The intended audience for this presentation is systems/software developers and managers in a large, research-oriented organization that may need to respond to imposed standards while also pursuing CMMI Maturity Level goals. A set of internally developed tools will be presented, including an overall Process Improvement Action Item database, a formal inspection/peer review tool, metrics collection spreadsheet, and other related technologies. The Center also found a need to charter Technical Working Groups (TWGs) to address particular Process Areas. In addition, a Marketing TWG was needed to communicate the process changes to the development community, including an innovative web site portal.

The Divine Deviance, Towards a sociological theory of Radical Islamism

DEFF Research Database (Denmark)

Rezaei, Shahamak; Goli, Marco

2011-01-01

and experts, and through methodological triangulation, awareness of the guidelines of the methodology of phenomenological theory (by development of codes, concepts, categories and finally theory and cross examination of widespread hypotheses) this study attempts: (a). To provide a conceptual clarification......Radical Islamism is widely appreciated as the very cognitive and ideological framework and denominator for the creation of a worldview that is hostile to the principles of pluralism and peaceful co-existence. Empirically tested knowledge of the phenomenon, as well as efforts to develop...... of the concept ‘Radical Islamis', (b) To introduce a falsifiable theoretical proposition to the question of the attributes of the phenomenon ‘Radical Islamism', and (c) To outline some empirical research implications of the proposed theoretical framework....

Changes in free-radical scavenging ability of kombucha tea during fermentation.

Science.gov (United States)

Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

2008-07-01

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

National Identity: Conceptual models, discourses and political change

DEFF Research Database (Denmark)

Harder, Peter

2014-01-01

of conceptual models or discourses. This is especially important in cases that involve conflictive political issues such as national and ethnic identity. The article reports on a historical project with a linguistic dimension in my department (PI Stuart Ward, cf. Ward 2004), which aims to throw light......Cognitive Linguistics has demonstrated the applicability of a conceptual approach to the understanding of political issues, cf. Lakoff (2008) and many others. From a different perspective, critical discourse analysis has approached political concepts with a focus on issues involving potentially...... divisive features such as race, class, gender and ethnic identity. Although discourses are not identical to conceptual models, conceptual models are typically manifested in discourse, and discourses are typically reflections of conceptualizations, a theme explored e.g. in Hart and Lukes (2007). As argued...

Students' beliefs, attitudes, and conceptual change in a traditional and a constructivistic high school physics classroom

Science.gov (United States)

Adams, April Dean

In this study, the relationships between student beliefs about the nature of science, student attitudes, and conceptual change about the nature of forces were investigated within a traditional and within a constructivistic high school physics classroom. Students in both classrooms were honors students taking a first year high school physics course and were primarily white and middle to upper SES. Students in the traditional classroom were all high ability juniors, and physics instruction was integrated with pre-calculus. Students in the constructivistic classroom were a mixture of juniors and seniors. Due to the interrelated nature of these factors and the complexity of their interactions, a naturalistic inquiry design was chosen. The data sources included videotape of 7-9 weeks of instruction; analysis of the videotapes using the Secondary Teacher Analysis Matrix (Gallagher & Parker, 1995); field notes; pretest/posttest assessment with the Force Concept Inventory (Hestenes, Wells, & Swackhammer, 1992); student responses from the Views on Science-Technology-Society questionnaire (Aikenhead & Ryan, 1992), the Questionnaire for the Assessment of a Science Course (Chiappetta, 1995), and the Constructivist Learning Environment Survey (Taylor, Fraser, & White, 1994); student interviews; and teacher interviews. In the traditional classroom, (a) students did not think that physics was relevant to everyday experiences; (b) high conceptual change students were more likely to have an angular world view (Cobern, 1993) and have views more similar to the teacher's about the nature of science; and (c) high conceptual change students were able to develop an internally consistent understanding of the content; however, that content appeared to be isolated knowledge in some students. In the constructivistic classroom, (a) students saw physics as relevant and useful; (b) there was no difference in world view or agreement with the teacher's views on the nature of science between high

Motivation to change in eating disorder patients: a conceptual clarification on the basis of self-determination theory.

Science.gov (United States)

Vansteenkiste, Maarten; Soenens, Bart; Vandereycken, Walter

2005-04-01

The current study critically reviews the different motivational frameworks that are applied in the study of eating disorders and provides a more comprehensive conceptualization of motivation to change on the basis of self-determination theory. The most important conceptualizations of motivation to change among eating disorder patients are identified. Eating disorder patients' motivation to change has been defined very differently, adding confusion to the field and preventing research from being cumulative. On the basis of self-determination theory we argue (a) that the quality of motivation to change is primarily reflected in the degree of internalization of change rather than by the intrinsic motivation to change; (b) that the internalization of change suggests more than only the change being initiated from within the person (internal motivation) for it requires an acceptance of the personal importance of change; and (c) that, in addition to its quality, the quantity of motivation to change should be considered too. These three conceptual issues are applied to the study of motivational dynamics in eating-disordered patients. 2005 by Wiley Periodicals, Inc.

Discussing the Greenhouse Effect: Children's Collaborative Discourse Reasoning and Conceptual Change.

Science.gov (United States)

Mason, Lucia; Santi, Marina

1998-01-01

Investigates fifth-grade students' conceptual changes toward the greenhouse effect and global warming due to sociocognitive interaction developed in small and large group discussion in an authentic classroom context during an environmental education unit. Classroom discussions led the children to integrate new scientific knowledge into their…

Promoting Scientific Thinking and Conceptual Change about Alternative Explanations of Climate Change and Other Controversial Socio-scientific Topics

Science.gov (United States)

Lombardi, D.; Sinatra, G. M.

2013-12-01

Critical evaluation and plausibility reappraisal of scientific explanations have been underemphasized in many science classrooms (NRC, 2012). Deep science learning demands that students increase their ability to critically evaluate the quality of scientific knowledge, weigh alternative explanations, and explicitly reappraise their plausibility judgments. Therefore, this lack of instruction about critical evaluation and plausibility reappraisal has, in part, contributed to diminished understanding about complex and controversial topics, such as global climate change. The Model-Evidence Link (MEL) diagram (originally developed by researchers at Rutgers University under an NSF-supported project; Chinn & Buckland, 2012) is an instructional scaffold that promotes students to critically evaluate alternative explanations. We recently developed a climate change MEL and found that the students who used the MEL experienced a significant shift in their plausibility judgments toward the scientifically accepted model of human-induced climate change. Using the MEL for instruction also resulted in conceptual change about the causes of global warming that reflected greater understanding of fundamental scientific principles. Furthermore, students sustained this conceptual change six months after MEL instruction (Lombardi, Sinatra, & Nussbaum, 2013). This presentation will discuss recent educational research that supports use of the MEL to promote critical evaluation, plausibility reappraisal, and conceptual change, and also, how the MEL may be particularly effective for learning about global climate change and other socio-scientific topics. Such instruction to develop these fundamental thinking skills (e.g., critical evaluation and plausibility reappraisal) is demanded by both the Next Generation Science Standards (Achieve, 2013) and the Common Core State Standards for English Language Arts and Mathematics (CCSS Initiative-ELA, 2010; CCSS Initiative-Math, 2010), as well as a

The Challenges to Human Resources Development of Libraries in Times of Radical and Generational Changes.

Science.gov (United States)

Muller, Uta

Librarianship has undergone a radical change in recent years, which will be continued in the future. Whereas previously the administration of media was most important, nowadays an ever increasing willingness to provide a service is required. In addition to the essential restructuring of libraries, a generational change is taking place within the…

Folkbiology Meets Microbiology: A Study of Conceptual and Behavioral Change

Science.gov (United States)

Au, Terry Kit-fong; Chan, Carol K. K.; Chan, Tsz-kit; Cheung, Mike W. L.; Ho, Johnson Y. S.; Ip, Grace W. M.

2008-01-01

Health education can offer a valuable window onto conceptual and behavioral change. In Study 1, we mapped out 3rd-grade Chinese children's beliefs about causes of colds and flu and ways they can be prevented. We also explored older adults' beliefs as a possible source of the children's ideas. In Study 2, we gave 3rd- and 4th-grade Chinese children…

One Size Does Not Fit All: Managing Radical and Incremental Creativity

Science.gov (United States)

Gilson, Lucy L.; Lim, Hyoun Sook; D'Innocenzo, Lauren; Moye, Neta

2012-01-01

This research extends creativity theory by re-conceptualizing creativity as a two-dimensional construct (radical and incremental) and examining the differential effects of intrinsic motivation, extrinsic rewards, and supportive supervision on perceptions of creativity. We hypothesize and find two distinct types of creativity that are associated…

Understanding the DSM-5: stasis and change.

Science.gov (United States)

Cooper, Rachel

2018-03-01

This paper aims to understand the DSM-5 through situating it within the context of the historical development of the DSM series. When one looks at the sets of diagnostic criteria, the DSM-5 is strikingly similar to the DSM-IV. I argue that at this level the DSM has become 'locked-in' and difficult to change. At the same time, at the structural, or conceptual, level there have been radical changes, for example in the definition of 'mental disorder', in the role of theory and of values, and in the abandonment of the multiaxial approach to diagnosis. The way that the DSM-5 was constructed means that the overall conceptual framework of the classification only barely constrains the sets of diagnostic criteria it contains.

A radical construction grammar perspective on the modal particle-discourse particle distinction

DEFF Research Database (Denmark)

Fischer, Kerstin; Alm, Maria

2013-01-01

between the contributions of lexical and grammatical constructions. In accordance with Croft’s (2001) Radical Construction Grammar approach, cross-linguistic comparison is then carried out on the basis of the conceptual space, which comprises the language specific sets of functions discourse and modal...

Bridging Scientific Reasoning and Conceptual Change through Adaptive Web-Based Learning

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She, Hsiao-Ching; Liao, Ya-Wen

2010-01-01

This study reports an adaptive digital learning project, Scientific Concept Construction and Reconstruction (SCCR), and examines its effects on 108 8th grade students' scientific reasoning and conceptual change through mixed methods. A one-group pre-, post-, and retention quasi-experimental design was used in the study. All students received tests…

Enhancing climate literacy through the use of an interdisciplinary global change framework and conceptual models

Science.gov (United States)

Bean, J. R.; Zoehfeld, K.; Mitchell, K.; Levine, J.; White, L. D.

2016-12-01

Understanding climate change and how to mitigate the causes and consequences of anthropogenic activities are essential components of the Next Generations Science Standards. To comprehend climate change today and why current rates and magnitudes of change are of concern, students must understand the various factors that drive Earth system processes and also how they interrelate. The Understanding Global Change web resource in development from the UC Museum of Paleontology will provide science educators with a conceptual framework, graphical models, lessons, and assessment templates for teaching NGSS aligned, interdisciplinary, climate change curricula. To facilitate students learning about the Earth as a dynamic, interacting system of ongoing processes, the Understanding Global Change site will provide explicit conceptual links for the causes of climate change (e.g., burning of fossil fuels, deforestation), Earth system processes (e.g., Earth's energy budget, water cycle), and the changes scientists measure in the Earth system (e.g., temperature, precipitation). The conceptual links among topics will be presented in a series of storyboards that visually represent relationships and feedbacks among components of the Earth system and will provide teachers with guides for implementing NGSS-aligned climate change instruction that addresses physical science, life sciences, Earth and space science, and engineering performance expectations. These visualization and instructional methods are used by teachers during professional development programs at UC Berkeley and the Smithsonian National Museum of Natural History and are being tested in San Francisco Bay Area classrooms.

Consciousness and Conscience: Feminism, Pragmatism, and the Potential for Radical Change

Directory of Open Access Journals (Sweden)

Clara Fischer

2010-04-01

Full Text Available

Pragmatist philosopher John Dewey famously stated that man is a creature of habit, and not of reason or instinct. In this paper, I will assess Dewey's explication of the habituated self and the potential it holds for radical transformative processes. In particular, I will examine the process of coming to feminist consciousness and will show that a feminist-pragmatist reading of change can accommodate a view of the self as responsible agent. Following the elucidation of the changing self, I will appraise key pragmatist concepts of inquiry, such as doubt and self-reflexivity, with regard to their treatment of deep-seated internalizations of oppressive norms and the initiation of change. Ultimately, I will argue that a feminist-pragmatist understanding of transformation is conducive not only to the project of personal transformation, but also to social and political change more generally.

Synchrotron radiation structure analyses of the light-induced radical pair of a hexaarylbiimidazolyl derivative. Origin of the spin-multiplicity change

CERN Document Server

Kawano, M; Matsubara, K; Imabayashi, H; Mitsumi, M; Toriumi, K; Ohashi, Y

2002-01-01

In situ synchrotron radiation structure analyses of a light-induced radical pair from o-Cl-HABI were performed by using an X-ray vacuum camera at 23-70K at the BL02B1 station of SPring-8. The combined results of X-ray analysis with theoretical calculation, IR, and UV-vis spectroscopy reveal that a slight conformational change of the radical pair causes the drastic spin-multiplicity change during 2-140K. (author)

Identification of Chemistry Learning Problems Viewed From Conceptual Change Model

OpenAIRE

Redhana, I. W; Sudria, I. B. N; Hidayat, I; Merta, L. M

2017-01-01

This study aimed at describing and explaining chemistry learning problems viewed from conceptual change model and misconceptions of students. The study was qualitative research of case study type conducted in one class of SMAN 1 Singaraja. Subjects of the study were a chemistry teacher and students. Data were obtained through classroom observation, interviews, and conception tests. The chemistry learning problems were grouped based on aspects of necessity, intelligibility, plausibility, and f...

Climate change and plant health; Development of a conceptual frame-work for impact assessment

NARCIS (Netherlands)

Breukers, M.L.H.

2010-01-01

This report presents a conceptual framework for systematic assessment of direct economic impacts of climate change on pest and disease management at the crop level. The framework evaluates and aggregates the effects, and subsequently impacts, of climate change on selected pests and diseases and

A conceptual framework to model long-run qualitative change in the energy system

OpenAIRE

Ebersberger, Bernd

2004-01-01

A conceptual framework to model long-run qualitative change in the energy system / A. Pyka, B. Ebersberger, H. Hanusch. - In: Evolution and economic complexity / ed. J. Stanley Metcalfe ... - Cheltenham [u.a.] : Elgar, 2004. - S. 191-213

On the Historical and Conceptual Foundations of a Community Psychology of Social Transformation.

Science.gov (United States)

Gokani, Ravi; Walsh, Richard T G

2017-06-01

We examine historical and conceptual literature in community psychology in order to understand the field's potential to be the socially transformative subdiscipline of psychology to which it aspires. By reviewing papers from two prominent journals and other literature, we conclude that the claim that community psychology is well-suited to social transformation, because it is a product of Sixties' radicalism and is theoretically equipped, is untenable. Systematic accounts of the subdiscipline's origins suggest that the transformative aspirations of current community psychologists do not correspond to the subdiscipline's reformist past. Furthermore, in analyzing three related concepts currently employed in the field-social justice, power, and praxis-we show that each suffers from conceptual ambiguity and a restricted political scope. These conceptual flaws, coupled with community psychology's historical inclination toward social reform, inhibit the possibility of contributing to radical social transformation. We conclude that neither questionable historical claims nor ambiguous and politically dubious concepts support a community psychology of social transformation. We offer solutions for the historical and conceptual problems we identify and, as a broader solution to the problem of engaging in socially transformative work, propose that community psychologists should seek direct political engagement in solidarity with other citizens as fellow citizens not as psychologists. © Society for Community Research and Action 2017.

A conceptual connectivity framework for understanding geomorphic change in human-impacted fluvial systems

Science.gov (United States)

Pöppl, Ronald; Keesstra, Saskia; Maroulis, Jerry

2017-04-01

Human-induced landscape change is difficult to predict due to the complexity inherent in both geomorphic and social systems as well as due to emerging coupling relationships between them. To better understand system complexity and system response to change, connectivity has become an important research paradigm within various disciplines including geomorphology, hydrology and ecology. With the proposed conceptual connectivity framework on geomorphic change in human-impacted fluvial systems a cautionary note is flagged regarding the need (i) to include and to systematically conceptualise the role of different types of human agency in altering connectivity relationships in geomorphic systems and (ii) to integrate notions of human-environment interactions to connectivity concepts in geomorphology to better explain causes and trajectories of landscape change. Underpinned by case study examples, the presented conceptual framework is able to explain how geomorphic response of fluvial systems to human disturbance is determined by system-specific boundary conditions (incl. system history, related legacy effects and lag times), vegetation dynamics and human-induced functional relationships (i.e. feedback mechanisms) between the different spatial dimensions of connectivity. It is further demonstrated how changes in social systems can trigger a process-response feedback loop between social and geomorphic systems that further governs the trajectory of landscape change in coupled human-geomorphic systems.

Using Conceptual Change Texts with Analogies for Misconceptions in Acids and Bases

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Cetingul, Ipek; Geban, Omer

2011-01-01

This study was conducted to explore the effectiveness of conceptual change oriented instruction over traditional instruction on students' understanding of acids and bases concept. Besides, effects of gender difference and science process skills on students' understanding of acids and bases were also investigated. Analysis of the results showed…

Use of Task-Value Instructional Inductions for Facilitating Engagement and Conceptual Change

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Johnson, Marcus Lee; Sinatra, Gale M.

2013-01-01

This study explored the relationship between task values, engagement, and conceptual change. One hundred and sixty-six under graduate students were randomly assigned to one of three task value instructional inductions (utility, attainment, and control) to determine whether induced task values would result in different degrees of engagement and…

Effectiveness of Conceptual Change Text-oriented Instruction on Students' Understanding of Energy in Chemical Reactions

Science.gov (United States)

Taştan, Özgecan; Yalçınkaya, Eylem; Boz, Yezdan

2008-10-01

The aim of this study is to compare the effectiveness of conceptual change text instruction (CCT) in the context of energy in chemical reactions. The subjects of the study were 60, 10th grade students at a high school, who were in two different classes and taught by the same teacher. One of the classes was randomly selected as the experimental group in which CCT instruction was applied, and the other as the control group in which traditional teaching method was used. The data were obtained through the use of Energy Concept Test (ECT), the Attitude Scale towards Chemistry (ASC) and Science Process Skill Test (SPST). In order to find out the effect of the conceptual change text on students' learning of energy concept, independent sample t-tests, ANCOVA (analysis of covariance) and ANOVA (analysis of variance) were used. Results revealed that there was a statistically significant mean difference between the experimental and control group in terms of students' ECT total mean scores; however, there was no statistically significant difference between the experimental and control group in terms of students' attitude towards chemistry. These findings suggest that conceptual change text instruction enhances the understanding and achievement.

Combining Different Conceptual Change Methods within 5E Model: A Sample Teaching Design of "Cell" Concept and its Organelles

Science.gov (United States)

Urey, Mustafa; Calik, Muammer

2008-01-01

Since students' misconceptions are not completely remedied by means of only one conceptual change method, the authors assume that using different conceptual methods embedded within the 5E model will not only be more effective in enhancing students' conceptual understanding, but also may eliminate all students' misconceptions. The aim of this study…

Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

Directory of Open Access Journals (Sweden)

Béla Fiser

Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

Physiology of free radicals

Directory of Open Access Journals (Sweden)

Stevanović Jelka

2011-01-01

Full Text Available Free radicals imply that every atom, molecule, ion, group of atoms, or molecules with one or several non-paired electrons in outer orbital. Among these are: nitrogenoxide (NO•, superoxide-anion-radical (O2•-, hydroxyl radical (OH•, peroxyl radical (ROO•, alcoxyl radical (RO• and hydroperoxyl radical (HO2•. However, reactive oxygen species also include components without non-paired electrons in outer orbital (so-called reactive non-radical agents, such as: singlet oxygen (1O2, peroxynitrite (ONOO-, hydrogen-peroxide (H2O2, hypochloric acid (eg. HOCl and ozone (O3. High concentrations of free radicals lead to the development of oxidative stress which is a precondition for numerous pathological effects. However, low and moderate concentrations of these matter, which occur quite normally during cell metabolic activity, play multiple significant roles in many reactions. Some of these are: regulation of signal pathways within the cell and between cells, the role of chemoattractors and leukocyte activators, the role in phagocytosis, participation in maintaining, changes in the position and shape of the cell, assisting the cell during adaption and recovery from damage (e.g.caused by physical effort, the role in normal cell growth, programmed cell death (apoptosis and cell ageing, in the synthesis of essential biological compounds and energy production, as well as the contribution to the regulation of the vascular tone, actually, tissue vascularization.

Basic perceptual changes that alter meaning and neural correlates of recognition memory

Directory of Open Access Journals (Sweden)

Chuanji eGao

2015-02-01

Full Text Available It is difficult to pinpoint the border between perceptual and conceptual processing, despite their treatment as distinct entities in many studies of recognition memory. For instance, alteration of simple perceptual characteristics of a stimulus can radically change meaning, such as the color of bread changing from white to green. We sought to better understand the role of perceptual and conceptual processing in memory by identifying the effects of changing a basic perceptual feature (color on behavioral and neural correlates of memory in circumstances when this change would be expected to either change the meaning of a stimulus or to have no effect on meaning (i.e., to influence conceptual processing or not. Abstract visual shapes (squiggles were colorized during study and presented during test in either the same color or a different color. Those squiggles that subjects found to resemble meaningful objects supported behavioral measures of conceptual priming, whereas meaningless squiggles did not. Further, changing color from study to test had a selective effect on behavioral correlates of priming for meaningful squiggles, indicating that color change altered conceptual processing. During a recognition memory test, color change altered event-related brain potential correlates of memory for meaningful squiggles but not for meaningless squiggles. Specifically, color change reduced the amplitude of frontally distributed N400 potentials (FN400, indicating that these potentials indicated conceptual processing during recognition memory that was sensitive to color change. In contrast, color change had no effect on FN400 correlates of recognition for meaningless squiggles, which were overall smaller in amplitude than for meaningful squiggles (further indicating that these potentials signal conceptual processing during recognition. Thus, merely changing the color of abstract visual shapes can alter their meaning, changing behavioral and neural correlates

Idea and Action: Action Research and the Development of Conceptual Change Teaching of Science.

Science.gov (United States)

Tabachnick, B. Robert; Zeichner, Kenneth M.

1999-01-01

Describes and analyzes an action-research seminar for prospective elementary and secondary teachers in terms of how it facilitated prospective teachers' learning to teach for conceptual change. Contains 37 references. (Author/WRM)

Change in chemical constituents and free radical-scavenging activity during Pear (Pyrus pyrifolia) cultivar fruit development.

Science.gov (United States)

Cho, Jeong-Yong; Lee, Sang-Hyun; Kim, Eun Hee; Yun, Hae Rim; Jeong, Hang Yeon; Lee, Yu Geon; Kim, Wol-Soo; Moon, Jae-Hak

2015-01-01

Changes in chemical constituent contents and DPPH radical-scavenging activity in fruits of pear (Pyrus pyrifolia) cultivars during the development were investigated. The fruits of seven cultivars (cv. Niitaka, Chuhwangbae, Wonhwang, Hwangkeumbae, Hwasan, Manpungbae, and Imamuraaki) were collected at 15-day intervals after day 20 of florescence. Vitamins (ascorbic acid and α-tocopherol), arbutin, chlorogenic acid, malaxinic acid, total caffeic acid, total flavonoids, and total phenolics were the highest in immature pear fruit on day 20 after florescence among samples at different growth stages. All of these compounds decreased gradually in the fruit during the development. Immature pear fruit on day 35 or 50 after florescence exhibited higher free radical-scavenging activity than that at other times, although activities were slightly different among cultivars. The chemical constituent contents and free radical-scavenging activity were largely different among immature fruits of the pear cultivars, but small differences were observed when they matured.

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

International Nuclear Information System (INIS)

Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

2015-01-01

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t d,E ) and hydroxyl-radical oxidation half-lives (t ·OH,E ) in sunlit surface waters. The t d,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas t ·OH,E ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways

Middle school students' conceptual change in global climate change: Using argumentation to foster knowledge construction

Science.gov (United States)

Golden, Barry W.

This research examined middle school student conceptions about global climate change (GCC) and the change these conceptions undergo during an argument driven instructional unit. The theoretical framework invoked for this study is the framework theory of conceptual change (Vosniadou, 2007a). This theory posits that students do not simply correct incorrect ideas with correct ones, but instead weigh incoming ideas against already existing explanatory frameworks, which have likely served the learner well to this point. The research questions were as follows: (1) What are the patterns of students' conceptual change in GCC? (a) What conceptions are invoked in student learning in this arena? (b) What conceptions are most influential? (c) What are the extra-rational factors influencing conceptual change in GCC? This research took place in an urban public school in a medium sized city in the southeastern United States. A sixth grade science teacher at Central Middle school, Ms. Octane, taught a course titled "Research Methods I., which was an elective science course that students took as part of a science magnet program. A unit was designed for 6th grade instruction that incorporated an Argument-Driven Inquiry (ADI) approach, centered on the subject matter of Global Climate change and Global Warming. Students were immersed in three separate lessons within the unit, each of which featured an emphasis upon creating scientific explanations based upon evidence. Additionally, each of the lessons placed a premium on students working towards the development of such explanations as a part of a group, with an emphasis on peer review of the robustness of the explanations proposed. The students were involved in approximately a two week unit emphasizing global climate change. This unit was based on an argumentation model that provided data to students and asked them to develop explanations that accounted for the data. The students then underwent a peer-review process to determine if

Conditions for the inauguration of a second nuclear era: chances of success of radical innovation

International Nuclear Information System (INIS)

Finon, D.

1999-01-01

Facing the stagnation of the world nuclear capacity, the commitments of Kyoto, the chances of re-mobilizing this technology in order to tackle the stakes of stabilisation of CO 2 emissions are assessed. The evolutionist economy of technical change offers a conceptual framework for the identification of factors of the incompatibility of nuclear technology with regard to the industrial, social and political environment in the majority of industrial economies. On the basis of this type of analysis, an examination of the conditions and chances for the re-launch of nuclear technology based on radical innovation designed to be in line with this environment is given. (author)

Stakeholder Participation in System Change: A New Conceptual Model.

Science.gov (United States)

O'Rourke, Tammy; Higuchi, Kathryn S; Hogg, William

2016-08-01

A recent change in Canada's primary care system led to the introduction of Nurse Practitioner-Led clinics. The literature suggests that stakeholders can influence system change initiatives. However, very little is known about healthcare stakeholder motivations, particularly stakeholders who are seen as resistors to change. To examine stakeholder participation in the system change process that led to the introduction of the first Nurse Practitioner-Led clinic in Ontario. This single case study included two site visits, semistructured individual tape-recorded interviews, and the examination of relevant public documents. Qualitative content analysis was used to analyze the data. Sixteen individuals from different healthcare sectors and professions participated in the interviews and 20 documents were reviewed. Six key themes emerged from the data. Linking Evidence to Action The findings from the study present a new perspective on stakeholder participation that includes both those who supported the proposed change and those who advocated for a different change. The findings identify stakeholder activities used to shape, share, and protect their visions for system change. The conceptual model presented in this study adds to the understanding of challenges and complexities involved in healthcare system change. Understanding why and how stakeholders participate in change can help healthcare leaders in planning activities to enhance stakeholder involvement in healthcare system change. © 2016 Sigma Theta Tau International.

Ordering theories: Typologies and conceptual frameworks for sociotechnical change

Science.gov (United States)

Sovacool, Benjamin K; Hess, David J

2017-01-01

What theories or concepts are most useful at explaining socio technical change? How can – or cannot – these be integrated? To provide an answer, this study presents the results from 35 semi-structured research interviews with social science experts who also shared more than two hundred articles, reports and books on the topic of the acceptance, adoption, use, or diffusion of technology. This material led to the identification of 96 theories and conceptual approaches spanning 22 identified disciplines. The article begins by explaining its research terms and methods before honing in on a combination of fourteen theories deemed most relevant and useful by the material. These are: Sociotechnical Transitions, Social Practice Theory, Discourse Theory, Domestication Theory, Large Technical Systems, Social Construction of Technology, Sociotechnical Imaginaries, Actor-Network Theory, Social Justice Theory, Sociology of Expectations, Sustainable Development, Values Beliefs Norms Theory, Lifestyle Theory, and the Unified Theory of Acceptance and Use of Technology. It then positions these theories in terms of two distinct typologies. Theories can be placed into five general categories of being centered on agency, structure, meaning, relations or norms. They can also be classified based on their assumptions and goals rooted in functionalism, interpretivism, humanism or conflict. The article lays out tips for research methodology before concluding with insights about technology itself, analytical processes associated with technology, and the framing and communication of results. An interdisciplinary theoretical and conceptual inventory has much to offer students, analysts and scholars wanting to study technological change and society. PMID:28641502

Effect of Conceptual Change Approach on Students' Understanding of Reaction Rate Concepts

Science.gov (United States)

Kingir, Sevgi; Geban, Omer

2012-01-01

The purpose of the present study was to investigate the effect of conceptual change text oriented instruction compared to traditional instruction on 10th grade students' understanding of reaction rate concepts. 45 students from two classes of the same teacher in a public high school participated in this study. Students in the experimental group…

Radical fashion and radical fashion innovation

NARCIS (Netherlands)

Zhang, D.; Benedetto, Di A.C.

2010-01-01

This is a study of the related concepts of radical fashion and radical fashion innovation. Radical fashions are defined here as those that may never enter the market at all, and exist primarily on runway shows, in exhibitions and in publicity; by contrast, radical fashion innovations may be very

Imagery Rescripting: The Impact of Conceptual and Perceptual Changes on Aversive Autobiographical Memories.

Directory of Open Access Journals (Sweden)

Christien Slofstra

Full Text Available Imagery rescripting (ImRs is a process by which aversive autobiographical memories are rendered less unpleasant or emotional. ImRs is thought only to be effective if a change in the meaning-relevant (semantic content of the mental image is produced, according to a cognitive hypothesis of ImRs. We propose an additional hypothesis: that ImRs can also be effective by the manipulation of perceptual features of the memory, without explicitly targeting meaning-relevant content.In two experiments using a within-subjects design (both N = 48, community samples, both Conceptual-ImRs-focusing on changing meaning-relevant content-and Perceptual-ImRs-focusing on changing perceptual features-were compared to Recall-only of aversive autobiographical image-based memories. An active control condition, Recall + Attentional Breathing (Recall+AB was added in the first experiment. In the second experiment, a Positive-ImRs condition was added-changing the aversive image into a positive image that was unrelated to the aversive autobiographical memory. Effects on the aversive memory's unpleasantness, vividness and emotionality were investigated.In Experiment 1, compared to Recall-only, both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in unpleasantness, and Perceptual-ImRs led to greater decreases in emotionality of memories. In Experiment 2, the effects on unpleasantness were not replicated, and both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in emotionality, compared to Recall-only, as did Positive-ImRs. There were no effects on vividness, and the ImRs conditions did not differ significantly from Recall+AB.Results suggest that, in addition to traditional forms of ImRs, targeting the meaning-relevant content of an image during ImRs, relatively simple techniques focusing on perceptual aspects or positive imagery might also yield benefits. Findings require replication and extension to clinical samples.

Imagery Rescripting: The Impact of Conceptual and Perceptual Changes on Aversive Autobiographical Memories.

Science.gov (United States)

Slofstra, Christien; Nauta, Maaike H; Holmes, Emily A; Bockting, Claudi L H

2016-01-01

Imagery rescripting (ImRs) is a process by which aversive autobiographical memories are rendered less unpleasant or emotional. ImRs is thought only to be effective if a change in the meaning-relevant (semantic) content of the mental image is produced, according to a cognitive hypothesis of ImRs. We propose an additional hypothesis: that ImRs can also be effective by the manipulation of perceptual features of the memory, without explicitly targeting meaning-relevant content. In two experiments using a within-subjects design (both N = 48, community samples), both Conceptual-ImRs-focusing on changing meaning-relevant content-and Perceptual-ImRs-focusing on changing perceptual features-were compared to Recall-only of aversive autobiographical image-based memories. An active control condition, Recall + Attentional Breathing (Recall+AB) was added in the first experiment. In the second experiment, a Positive-ImRs condition was added-changing the aversive image into a positive image that was unrelated to the aversive autobiographical memory. Effects on the aversive memory's unpleasantness, vividness and emotionality were investigated. In Experiment 1, compared to Recall-only, both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in unpleasantness, and Perceptual-ImRs led to greater decreases in emotionality of memories. In Experiment 2, the effects on unpleasantness were not replicated, and both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in emotionality, compared to Recall-only, as did Positive-ImRs. There were no effects on vividness, and the ImRs conditions did not differ significantly from Recall+AB. Results suggest that, in addition to traditional forms of ImRs, targeting the meaning-relevant content of an image during ImRs, relatively simple techniques focusing on perceptual aspects or positive imagery might also yield benefits. Findings require replication and extension to clinical samples.

Exploring Indigenous Game-Based Physics Activities in Pre-Service Physics Teachers' Conceptual Change and Transformation of Epistemic Beliefs

Science.gov (United States)

Morales, Marie Paz Escaño

2017-01-01

"Laro-ng-Lahi" (Indigenous Filipino game) based physics activities invigorated the integration of culture in the pre-service physics education to develop students' epistemic beliefs and the notion of conceptual understanding through conceptual change. The study conveniently involved 28 pre-service undergraduate physics students enrolled…

Engineering a horseradish peroxidase C stable to radical attacks by mutating multiple radical coupling sites.

Science.gov (United States)

Kim, Su Jin; Joo, Jeong Chan; Song, Bong Keun; Yoo, Young Je; Kim, Yong Hwan

2015-04-01

Peroxidases have great potential as industrial biocatalysts. In particular, the oxidative polymerization of phenolic compounds catalyzed by peroxidases has been extensively examined because of the advantage of this method over other conventional chemical methods. However, the industrial application of peroxidases is often limited because of their rapid inactivation by phenoxyl radicals during oxidative polymerization. In this work, we report a novel protein engineering approach to improve the radical stability of horseradish peroxidase isozyme C (HRPC). Phenylalanine residues that are vulnerable to modification by the phenoxyl radicals were identified using mass spectrometry analysis. UV-Vis and CD spectra showed that radical coupling did not change the secondary structure or the active site of HRPC. Four phenylalanine (Phe) residues (F68, F142, F143, and F179) were each mutated to alanine residues to generate single mutants to examine the role of these sites in radical coupling. Despite marginal improvement of radical stability, each single mutant still exhibited rapid radical inactivation. To further reduce inactivation by radical coupling, the four substitution mutations were combined in F68A/F142A/F143A/F179A. This mutant demonstrated dramatic enhancement of radical stability by retaining 41% of its initial activity compared to the wild-type, which was completely inactivated. Structure and sequence alignment revealed that radical-vulnerable Phe residues of HPRC are conserved in homologous peroxidases, which showed the same rapid inactivation tendency as HRPC. Based on our site-directed mutagenesis and biochemical characterization, we have shown that engineering radical-vulnerable residues to eliminate multiple radical coupling can be a good strategy to improve the stability of peroxidases against radical attack. © 2014 Wiley Periodicals, Inc.

Implementing change in primary care practices using electronic medical records: a conceptual framework.

Science.gov (United States)

Nemeth, Lynne S; Feifer, Chris; Stuart, Gail W; Ornstein, Steven M

2008-01-16

Implementing change in primary care is difficult, and little practical guidance is available to assist small primary care practices. Methods to structure care and develop new roles are often needed to implement an evidence-based practice that improves care. This study explored the process of change used to implement clinical guidelines for primary and secondary prevention of cardiovascular disease in primary care practices that used a common electronic medical record (EMR). Multiple conceptual frameworks informed the design of this study designed to explain the complex phenomena of implementing change in primary care practice. Qualitative methods were used to examine the processes of change that practice members used to implement the guidelines. Purposive sampling in eight primary care practices within the Practice Partner Research Network-Translating Researching into Practice (PPRNet-TRIP II) clinical trial yielded 28 staff members and clinicians who were interviewed regarding how change in practice occurred while implementing clinical guidelines for primary and secondary prevention of cardiovascular disease and strokes. A conceptual framework for implementing clinical guidelines into primary care practice was developed through this research. Seven concepts and their relationships were modelled within this framework: leaders setting a vision with clear goals for staff to embrace; involving the team to enable the goals and vision for the practice to be achieved; enhancing communication systems to reinforce goals for patient care; developing the team to enable the staff to contribute toward practice improvement; taking small steps, encouraging practices' tests of small changes in practice; assimilating the electronic medical record to maximize clinical effectiveness, enhancing practices' use of the electronic tool they have invested in for patient care improvement; and providing feedback within a culture of improvement, leading to an iterative cycle of goal setting

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

Energy Technology Data Exchange (ETDEWEB)

Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Siyu [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Ren, Honglei; Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

2015-09-15

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t{sub d,E}) and hydroxyl-radical oxidation half-lives (t{sub ·OH,E}) in sunlit surface waters. The t{sub d,E} values range from 0.56 min to 28.8 min at 45° N latitude, whereas t{sub ·OH,E} ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways.

Basic perceptual changes that alter meaning and neural correlates of recognition memory.

Science.gov (United States)

Gao, Chuanji; Hermiller, Molly S; Voss, Joel L; Guo, Chunyan

2015-01-01

It is difficult to pinpoint the border between perceptual and conceptual processing, despite their treatment as distinct entities in many studies of recognition memory. For instance, alteration of simple perceptual characteristics of a stimulus can radically change meaning, such as the color of bread changing from white to green. We sought to better understand the role of perceptual and conceptual processing in memory by identifying the effects of changing a basic perceptual feature (color) on behavioral and neural correlates of memory in circumstances when this change would be expected to either change the meaning of a stimulus or to have no effect on meaning (i.e., to influence conceptual processing or not). Abstract visual shapes ("squiggles") were colorized during study and presented during test in either the same color or a different color. Those squiggles that subjects found to resemble meaningful objects supported behavioral measures of conceptual priming, whereas meaningless squiggles did not. Further, changing color from study to test had a selective effect on behavioral correlates of priming for meaningful squiggles, indicating that color change altered conceptual processing. During a recognition memory test, color change altered event-related brain potential (ERP) correlates of memory for meaningful squiggles but not for meaningless squiggles. Specifically, color change reduced the amplitude of frontally distributed N400 potentials (FN400), implying that these potentials indicated conceptual processing during recognition memory that was sensitive to color change. In contrast, color change had no effect on FN400 correlates of recognition for meaningless squiggles, which were overall smaller in amplitude than for meaningful squiggles (further indicating that these potentials signal conceptual processing during recognition). Thus, merely changing the color of abstract visual shapes can alter their meaning, changing behavioral and neural correlates of memory

An educational ethnography of teacher-developed science curriculum implementation: Enacting conceptual change-based science inquiry with Hispanic students

Science.gov (United States)

Brunsell, Eric Steven

An achievement gap exists between White and Hispanic students in the United States. Research has shown that improving the quality of instruction for minority students is an effective way to narrow this gap. Science education reform movements emphasize that science should be taught using a science inquiry approach. Extensive research in teaching and learning science also shows that a conceptual change model of teaching is effective in helping students learn science. Finally, research into how Hispanic students learn best has provided a number of suggestions for science instruction. The Inquiry for Conceptual Change model merges these three research strands into a comprehensive yet accessible model for instruction. This study investigates two questions. First, what are teachers' perceptions of science inquiry and its implementation in the classroom? Second, how does the use of the Inquiry for Conceptual Change model affect the learning of students in a predominantly Hispanic, urban neighborhood. Five teachers participated in a professional development project where they developed and implemented a science unit based on the Inquiry for Conceptual Change model. Three units were developed and implemented for this study. This is a qualitative study that included data from interviews, participant reflections and journals, student pre- and post-assessments, and researcher observations. This study provides an in-depth description of the role of professional development in helping teachers understand how science inquiry can be used to improve instructional quality for students in a predominantly Hispanic, urban neighborhood. These teachers demonstrated that it is important for professional development to be collaborative and provide opportunities for teachers to enact and reflect on new teaching paradigms. This study also shows promising results for the ability of the Inquiry for Conceptual Change model to improve student learning.

Online Discussion as a Mechanism of Conceptual Change among Mathematics and Science Teachers

Science.gov (United States)

Luebeck, Jennifer L.; Bice, Lawrence R.

2005-01-01

This study examines the extent to which conceptual change is stimulated and achieved through online discussion in the context of an online graduate course. Transcripts of discussions among 15 graduate students studying assessment issues in mathematics and science education were analyzed using an interaction analysis model developed to assess…

The Effect of Cooperative Learning Approach Based on Conceptual Change Condition on Students' Understanding of Chemical Equilibrium Concepts

Science.gov (United States)

Bilgin, Ibrahim; Geban, Omer

2006-01-01

The purpose of this study is to investigate the effects of the cooperative learning approach based on conceptual change conditions over traditional instruction on 10th grade students' conceptual understanding and achievement of computational problems related to chemical equilibrium concepts. The subjects of this study consisted of 87 tenth grade…

Structuring Cooperative Learning for Motivation and Conceptual Change in the Concepts of Mixtures

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Belge Can, Hatice; Boz, Yezdan

2016-01-01

This study investigates the effect of structuring cooperative learning based on conceptual change approach on grade 9 students' understanding the concepts of mixtures and their motivation, compared with traditional instruction. Among six classes of a high school, two of them were randomly assigned to cooperative learning group where students were…

Learning in Earth and Space Science: A Review of Conceptual Change Instructional Approaches

Science.gov (United States)

Mills, Reece; Tomas, Louisa; Lewthwaite, Brian

2016-01-01

In response to calls for research into effective instruction in the Earth and space sciences, and to identify directions for future research, this systematic review of the literature explores research into instructional approaches designed to facilitate conceptual change. In total, 52 studies were identified and analyzed. Analysis focused on the…

Conceptual Change in Psychology Students' Acceptance of the Scientific Foundation of the Discipline

Science.gov (United States)

Amsel, Eric; Ashley, Aaron; Baird, Todd; Johnston, Adam

2014-01-01

Two studies explored conceptual change in undergraduate psychology students' acceptance of the scientific foundations of the discipline. In Study 1, Introductory Psychology students completed the Psychology as Science questionnaire (PAS) at the beginning and end of the semester and did so from their own (Self Condition) and their instructors'…

Conceptions and characterization : an explanation for the theory-practice gap in conceptual change theory

NARCIS (Netherlands)

Eijck, van M.W.; Roth, W.-M.

2010-01-01

For more than 2 decades now, conceptual change theory has been lauded as a powerful framework for improving science teaching and learning. This has resulted in an increasingly sophisticated theory building, yielding, among other things, a comprehensive documentation of students’ (mis-, alternative,

Understanding Global Change: A New Conceptual Framework To Guide Teaching About Planetary Systems And Both The Causes And Effects Of Changes In Those Systems

Science.gov (United States)

Levine, J.; Bean, J. R.

2016-12-01

Goals of the Next Generation Science Standards include understanding climate change and learning about ways to moderate the causes and mitigate the consequences of planetary-scale anthropogenic activities that interact synergistically to affect ecosystems and societies. The sheer number and scale of both causes and effects of global change can be daunting for teachers, and the lack of a clear conceptual framework for presenting this material usually leads educators (and textbooks) to present these phenomenon as a disjointed "laundry list." But an alternative approach is in the works. The Understanding Global Change web resource, currently under development at the UC Berkeley Museum of Paleontology, will provide educators with a conceptual framework, graphic models, lessons, and assessment templates for teaching NGSS-aligned, interdisciplinary, global change curricula. The core of this resource is an original informational graphic that presents and relates Earth's global systems, human and non-human factors that produce changes in those systems, and the effects of those changes that scientists can measure.

The Effect of Conceptual Change Pedagogy on Students' Conceptions of Rate of Reaction

Science.gov (United States)

Calik, Muammer; Kolomuc, Ali; Karagolge, Zafer

2010-01-01

This paper reports on an investigation of the effect of conceptual change pedagogy on students' conceptions of "rate of reaction" concepts. The study used a pre-test/post-test non-equivalent comparison group design approach and the sample consisted of 72 Turkish grade-11 students (aged 16-18 years) selected from two intact classrooms.…

Testing a Conceptual Change Model Framework for Visual Data

Science.gov (United States)

Finson, Kevin D.; Pedersen, Jon E.

2015-01-01

An emergent data analysis technique was employed to test the veracity of a conceptual framework constructed around visual data use and instruction in science classrooms. The framework incorporated all five key components Vosniadou (2007a, 2007b) described as existing in a learner's schema: framework theory, presuppositions, conceptual domains,…

Environmental context effects in conceptual explicit and implicit memory.

Science.gov (United States)

Parker, Andrew; Dagnall, Neil; Coyle, Anne-Marie

2007-05-01

Previous research has found environmental context effects for both conceptual explicit and conceptual implicit memory (Parker, Gellatly, & Waterman, 1999). The research presented here challenges these findings on methodological grounds. Experiment 1 assessed the effects of context change on category-exemplar generation (conceptual implicit memory test) and category-cued recall (conceptual explicit memory test). Experiment 2 assessed the effects of context change on word association (conceptual implicit memory test) and word associate cued recall (conceptual explicit memory test). In both experiments, study-test changes in environmental context were found to influence performance only on tests of explicit memory. It is concluded that when retrieval cues across explicit and implicit tests are matched, and the probability of explicit contamination is reduced, then only conceptual explicit test performance is reduced by study-test changes in environmental context.

Glutathione as a radical scavenger and the biological consequences of thiyl radical production

International Nuclear Information System (INIS)

Winterbourn, C.C.

1996-01-01

A large number of compounds that have toxic effects can be metabolised to free radicals and secondary reactive oxygen species. These may be directly damaging or affect cell function by altering regulatory mechanisms through changing redox status. Protection is provided by an integrated system of antioxidant defenses. This includes reduced glutathione (GSH), one of the functions of which is as a free radical scavenger. For GSH to be an effective radical scavenging antioxidant, therefore, it must act in concert with superoxide dismutase to remove the superoxide so generated. Superoxide is produced in a variety of metabolic processes. It is also a secondary product of radicals reacting with oxygen either directly or through GSH. The biological reactivity of superoxide has been the subject of much debate ever since the discovery of superoxide dismutase in 1968. It has more recently become apparent that its rapid reaction with nitric oxide to give peroxynitrite, and its ability to reversibly oxidise and inactivate iron sulphur enzymes, contribute to the toxicity of superoxide. Another mechanism that could be important involves addition reactions of superoxide with other radicals to give organic peroxides. This reaction, to form a tyrosine peroxide, has come to authors attention through the study of the scavenging of tyrosyl radicals by GSH. It is also shown that a tyrosine peroxide is a major product of the oxidation of tyrosine by neutrophils

Self-Regulated Learning: The Continuous-Change Conceptual Framework and a Vision of New Paradigm, Technology System, and Pedagogical Support

Science.gov (United States)

Huh, Yeol; Reigeluth, Charles M.

2017-01-01

A modified conceptual framework called the Continuous-Change Framework for self-regulated learning (SRL) is presented. Common elements and limitations among the past frameworks are discussed in relation to the modified conceptual framework. The iterative nature of the goal setting process and overarching presence of self-efficacy and motivational…

Ideological Radicalization: A Conceptual Framework for Understanding Why Youth in Major U.S. Metropolitan Areas Are More Likely to Become Radicalized

Science.gov (United States)

2017-05-05

Table 1. Risk Factors Associated with Delinquency by Domain ............................35 Table 2. Youth Disconnection in the United States, Canada...right wing or jihadist), and it includes about 30 variables listed in Appendix A. First, this thesis includes an analysis of the descriptive statistics ...of the issue. Chapter V provides as quantitative statistical analysis to examine and explore the relationship between radicalization and

Patient-reported outcome (PRO) questionnaires for men who have radical surgery for prostate cancer: a conceptual review of existing instruments.

Science.gov (United States)

Protopapa, Evangelia; van der Meulen, Jan; Moore, Caroline M; Smith, Sarah C

2017-10-01

To critically review conceptual frameworks for available patient-reported outcome (PRO) questionnaires in men having radical prostatectomy (RP), psychometrically evaluate each questionnaire, and identify whether each is appropriate for use at the level of the individual patient. We searched PubMed, the Reports and Publications database of the University of Oxford Patient-Reported Outcomes Measurement Group and the website of the International Consortium for Health Outcomes Measurement (ICHOM) for psychometric reviews of prostate cancer-specific PRO questionnaires. From these we identified relevant questionnaires and critically appraised the conceptual content, guided by the Wilson and Cleary framework and psychometric properties, using well established criteria. The searches found four reviews and one recommendation paper. We identified seven prostate cancer-specific PROs: the Expanded Prostate Cancer Index Composite-26 (EPIC-26), Expanded Prostate Cancer Index Composite-50 (EPIC-50), University of California-Los Angeles Prostate Cancer Index (UCLA-PCI), Functional Assessment of Cancer Therapy - Prostate Cancer Subscale (FACT-P PCS), European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire - prostate specific 25-item (EORTC QLQ-PR25), Prostate Cancer - Quality of Life (PC-QoL), and Symptom Tracking and Reporting (STAR). Six out of seven measures purported to measure health-related quality of life (HRQL), but items focused strongly on urinary and sexual symptoms/functioning. The remaining questionnaire (STAR) claimed to assess functional recovery after RP. The psychometric evidence for these questionnaires was incomplete and variable in quality; none had evidence that they were appropriate for use with individual patients. Several questionnaires provide the basis of measures of urinary and/or sexual symptoms/functioning. Further work should explore other aspects of HRQL that are important for men having RP. Further psychometric work

Effect of Conceptual Change Texts for Overcoming Misconceptions in "People and Management" Unit

Science.gov (United States)

Dagdelen, Orhan; Kosterelioglu, Ilker

2015-01-01

This study aimed to investigate the effects of conceptual change texts in teaching concepts in the "People and Management" Unit of a Social Studies Course. The working group of the study was composed of 4th graders in a primary school in Çorum, assigned as control (n = 23) and experimental (n = 23) groups. Non-equivalent control group…

Hemodynamic changes during robotic radical prostatectomy

Directory of Open Access Journals (Sweden)

Vanlal Darlong

2012-01-01

Full Text Available Background: Effect on hemodynamic changes and experience of robot-assisted laparoscopic radical prostatectomy (RALRP in steep Trendelenburg position (45° with high-pressure CO 2 pneumoperitoneum is very limited. Therefore, we planned this prospective clinical trial to study the effect of steep Tredelenburg position with high-pressure CO 2 pneumoperitoneum on hemodynamic parameters in a patient undergoing RALRP using FloTrac/Vigileo™1.10. Methods: After ethical approval and informed consent, 15 patients scheduled for RALRP were included in the study. In the operation room, after attaching standard monitors, the radial artery was cannulated. Anesthesia was induced with fentanyl (2 μg/kg and thiopentone (4-7 mg/kg, and tracheal intubation was facilitated by vecuronium bromide (0.1 mg/kg. The patient′s right internal jugular vein was cannulated and the Pre Sep™ central venous oximetry catheter was connected to it. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide and intermittent boluses of vecuronium. Intermittent positive-pressure ventilation was provided to maintain normocapnea. After CO 2 pneumoperitoneum, position of the patient was gradually changed to 45° Trendelenburg over 5 min. The robot was then docked and the robot-assisted surgery started. Intraoperative monitoring included central venous pressure (CVP, stroke volume (SV, stroke volume variation (SVV, cardiac output (CO, cardiac index (CI and central venous oxygen saturation (ScvO 2 . Results: After induction of anesthesia, heart rate (HR, SV, CO and CI were decreased significantly from the baseline value (P>0.05. SV, CO and CI further decreased significantly after creating pneumoperitoneum (P>0.05. At the 45° Trendelenburg position, HR, SV, CO and CI were significantly decreased compared with baseline. Thereafter, CO and CI were persistently low throughout the 45° Trendelenburg position (P=0.001. HR at 20 min and 1 h, SV and mean arterial blood pressure

Posttraumatic Stress Disorder in the DSM-5: Controversy, Change, and Conceptual Considerations

Directory of Open Access Journals (Sweden)

Anushka Pai

2017-02-01

Full Text Available The criteria for posttraumatic stress disorder PTSD have changed considerably with the newest edition of the American Psychiatric Association’s (APA Diagnostic and Statistical Manual of Mental Disorders (DSM-5. Changes to the diagnostic criteria from the DSM-IV to DSM-5 include: the relocation of PTSD from the anxiety disorders category to a new diagnostic category named “Trauma and Stressor-related Disorders”, the elimination of the subjective component to the definition of trauma, the explication and tightening of the definitions of trauma and exposure to it, the increase and rearrangement of the symptoms criteria, and changes in additional criteria and specifiers. This article will explore the nosology of the current diagnosis of PTSD by reviewing the changes made to the diagnostic criteria for PTSD in the DSM-5 and discuss how these changes influence the conceptualization of PTSD.

Thermal evolution of the morphology of Ni/Ag/Si(111)-{radical}3 Multiplication-Sign {radical}3 surface

Energy Technology Data Exchange (ETDEWEB)

Tomaszewska, Agnieszka; Huang, Xiao-Lan; Chang, Kuo-Wei; Fu, Tsu-Yi, E-mail: phtifu@phy.ntnu.edu.tw

2012-08-31

The temperature-driven changes in morphology of the interface formed by room temperature (RT) deposition of Ni atoms onto an Ag/Si(111)-{radical}3 Multiplication-Sign {radical}3 surface were investigated by scanning tunneling microscopy. Roughly 70% of Ni deposition diffused into bulk substrate within the temperature range between RT and 573 K. The images as obtained after annealing up to 670 K correspond to the formation of nano-sized islands of nickel silicides. Two types of islands, large triangular islands typical of the whole range of applied coverage, and smaller islands of different shapes, coexist at Ni coverage higher than 1 monolayer. Annealing above 870 K led to the formation of a 7 Multiplication-Sign 7 phase in coexistence with small 5 Multiplication-Sign 5 domains at the expense of a complete disappearance of the {radical}3 Multiplication-Sign {radical}3 phase. Also, formation of Ni,Si alloy was observed at the temperature, along with segregation of bulk-dissolved Ni species onto the surface. - Highlights: Black-Right-Pointing-Pointer We examine changes in morphology of Ni/Ag/Si(111)-{radical}3 Multiplication-Sign {radical}3 surface upon annealing. Black-Right-Pointing-Pointer 70% of deposited Ni atoms diffuse into the bulk after annealing at 570 K. Black-Right-Pointing-Pointer A variety of nano-sized Ni, Si islands develops after annealing at 670 K. Black-Right-Pointing-Pointer 5 Multiplication-Sign 5 reconstruction as an evidence for mass transport during the island growth.

OH radical induced depolymerization of poly(methacrylic acid)

Science.gov (United States)

Ulanski, Piotr; Bothe, Eberhard; von Sonntag, Clemens

1999-05-01

Hydroxyl radicals (generated pulse radiolytically in dilute N 2O-saturated aqueous solutions) react with poly(methacrylic acid) producing two kinds of radicals. The primary radical is converted into a secondary one by H-abstraction ( k=3.5 × 10 2 s -1) as monitored by changes in the UV spectrum. Subsequently, the secondary radicals undergo chain scission ( k=1.8 s -1 at pH 7-9). This process has been followed both by spectrophotometry as well as by conductometry. In competition with the bimolecular decay of the radicals the ensuing end-chain radicals undergo efficient depolymerization resulting in the release of monomer. Since the lifetime of the radicals is much longer at high pH, where the polymer attains a rod-like conformation, depolymerization is most efficient in basic solution.

Radical-pair based avian magnetoreception

Science.gov (United States)

Procopio, Maria; Ritz, Thorsten

2014-03-01

Behavioural experiments suggest that migratory birds possess a magnetic compass sensor able to detect the direction of the geomagnetic. One hypothesis for the basis of this remarkable sensory ability is that the coherent quantum spin dynamics of photoinduced radical pair reactions transduces directional magnetic information from the geomagnetic field into changes of reaction yields, possibly involving the photoreceptor cryptochrome in the birds retina. The suggested radical-pair based avian magnetoreception has attracted attention in the field of quantum biology as an example of a biological sensor which might exploit quantum coherences for its biological function. Investigations on such a spin-based sensor have focussed on uncovering the design features for the design of a biomimetic magnetic field sensor. We study the effects of slow fluctuations in the nuclear spin environment on the directional signal. We quantitatively evaluate the robustness of signals under fluctuations on a timescale longer than the lifetime of a radical pair, utilizing two models of radical pairs. Our results suggest design principles for building a radical-pair based compass sensor that is both robust and highly directional sensitive.

Conceptual model for dietary behaviour change at household level: a 'best-fit' qualitative study using primary data.

Science.gov (United States)

Daivadanam, Meena; Wahlström, Rolf; Ravindran, T K Sundari; Thankappan, K R; Ramanathan, Mala

2014-06-09

Interventions having a strong theoretical basis are more efficacious, providing a strong argument for incorporating theory into intervention planning. The objective of this study was to develop a conceptual model to facilitate the planning of dietary intervention strategies at the household level in rural Kerala. Three focus group discussions and 17 individual interviews were conducted among men and women, aged between 23 and 75 years. An interview guide facilitated the process to understand: 1) feasibility and acceptability of a proposed dietary behaviour change intervention; 2) beliefs about foods, particularly fruits and vegetables; 3) decision-making in households with reference to food choices and access; and 4) to gain insights into the kind of intervention strategies that may be practical at community and household level. The data were analysed using a modified form of qualitative framework analysis, which combined both deductive and inductive reasoning. A priori themes were identified from relevant behaviour change theories using construct definitions, and used to index the meaning units identified from the primary qualitative data. In addition, new themes emerging from the data were included. The associations between the themes were mapped into four main factors and its components, which contributed to construction of the conceptual model. Thirteen of the a priori themes from three behaviour change theories (Trans-theoretical model, Health Belief model and Theory of Planned Behaviour) were confirmed or slightly modified, while four new themes emerged from the data. The conceptual model had four main factors and its components: impact factors (decisional balance, risk perception, attitude); change processes (action-oriented, cognitive); background factors (personal modifiers, societal norms); and overarching factors (accessibility, perceived needs and preferences), built around a three-stage change spiral (pre-contemplation, intention, action). Decisional

A Lakatosian Conceptual Change Teaching Strategy Based on Student Ability to Build Models with Varying Degrees of Conceptual Understanding of Chemical Equilibrium

Science.gov (United States)

Niaz, M.

The main objective of this study is to construct a Lakatosian teaching strategy that can facilitate conceptual change in students'' understanding of chemical equilibrium. The strategy is based on the premise that cognitive conflicts must have been engendered by the students themselves in trying to cope with different problem solving strategies. Results obtained (based on Venezuelan freshman students) show that the performance of the experimental group of students was generally better (especially on the immediate post tests) than that of the control group. It is concluded that a conceptual change teaching strategy must take into consideration the following aspects: a) core beliefs of the students in the topic (cf. ''hard core'', Lakatos 1970); b) exploration of the relationship between core beliefs and student alternative conceptions (misconceptions); c) cognitive complexity of the core belief can be broken down into a series of related and probing questions; d) students resist changes in their core beliefs by postulating ''auxiliary hypotheses'' in order to resolve their contradictions; e) students'' responses based on their alternative conceptions must be considered not as wrong, but rather as models, perhaps in the same sense as used by scientists to break the complexity of a problem; and f) students'' misconceptions be considered as alternative conceptions (theories) that compete with the present scientific theories and at times recapitulate theories scientists held in the past.

Emergent Innovation—a Socio-Epistemological Innovation Technology. Creating Profound Change and Radically New Knowledge as Core Challenges in Knowledge Management

OpenAIRE

Peschl, Markus F.; Fundneider, Thomas

2008-01-01

This paper introduces an alternative approach to innovation: Emergent Innovation. As opposed to radical innovation Emergent Innovation finds a balance and integrates the demand both for radically new knowledge and at the same time for an organic development from within the organization. From a knowledge management perspective one can boil down this problem to the question of how to cope with the new and with profound change in knowledge. This question will be dealt with in the first part of t...

Radical feminists & trans activists truce

OpenAIRE

Mackay, F.

2014-01-01

#GenderWeek: Truce! When radical feminists and trans feminists empathise\\ud Feminist Times\\ud By Finn Mackay \\ud read all #GenderWeek articles.\\ud We wanted to explore the ground between the polarised, entrenched positions in the so-called “TERF-war”. Radical feminists on one pole, trans-inclusionary feminists and trans activists on the other. The disputed territory being women-only space, language and the ever changing legal framework surrounding gender.\\ud Entrenchment leads to stalemate. S...

Taking a radical position: Evidence for position specific radical representations in Chinese character recognition using masked priming ERP

Directory of Open Access Journals (Sweden)

I-Fan eSu

2012-09-01

Full Text Available In the investigation of orthographic representation of Chinese characters, one question that has stimulated much research is whether radicals (character components are specified for spatial position in a character (e.g. Ding, Peng, & Taft, 2004; Tsang & Chen, 2009. Differing from previous work, component or radical position information in this study is conceived in terms of relative frequency across different positions of characters containing it. A lexical decision task in a masked priming paradigm focusing on radicals with preferred position of occurrence was conducted. A radical position that encompasses more characters than other positions was identified to be the preferred position of a particular radical. The prime that was exposed for 96ms might share a radical with the target in the same or different positions. Moreover, the shared radical appeared either in its preferred or non-preferred position in the target. While response latencies only revealed the effect of graphical similarity, both effects of graphical similarity and radical position preference were found in the ERP results. The former effect was reflected in greater positivity in occipital P1 and greater negativity in N400 for radicals in different positions in prime and target characters. The latter effect manifested as greater negativity in occipital N170 and greater positivity in frontal P200 in the same time window elicited by radicals in their non-preferred position. Equally interesting was the reversal of the effect of radical position preference in N400 with greater negativity associated with radicals in preferred position. These findings identify the early ERP components associated with activation of position-specific radical representations in the orthographic lexicon, and reveal the change in the nature of competition from processing at the radical level to the lexical level.

Effects of Conceptual Change Text Based Instruction on Ecology, Attitudes toward Biology and Environment

Science.gov (United States)

Çetin, Gülcan; Ertepinar, Hamide; Geban, Ömer

2015-01-01

The purpose of this study is to investigate the effects of the conceptual change text based instruction on ninth grade students' understanding of ecological concepts, and attitudes toward biology and environment. Participants were 82 ninth grade students in a public high school in the Northwestern Turkey. A treatment was employed over a five-week…

Identifying students’ mental models of sound propagation: The role of conceptual blending in understanding conceptual change

Directory of Open Access Journals (Sweden)

Zdeslav Hrepic

2010-09-01

Full Text Available We investigated introductory physics students’ mental models of sound propagation. We used a phenomenographic method to analyze the data in the study. In addition to the scientifically accepted Wave model, students used the “Entity” model to describe the propagation of sound. In this latter model sound is a self-standing entity, different from the medium through which it propagates. All other observed alternative models contain elements of both Entity and Wave models, but at the same time are distinct from each of the constituent models. We called these models “hybrid” or “blend” models. We discuss how students use these models in various contexts before and after instruction and how our findings contribute to the understanding of conceptual change. Implications of our findings for teaching are summarized.

Development of a Template Lesson Plan Based on 5e Model Enhanced with Computer Supported Applications and Conceptual Change Texts

Science.gov (United States)

Seker, Burcu Sezginsoy; Erdem, Aliye

2017-01-01

Students learning a defined subject only perform by learning of thinking based on the concepts forming that subjects. Otherwise, students may move away from the scientific meaning of concepts and may fall into conceptual errors. Students' conceptual errors affect their following learning and cause them resist change. It is possible to prevent this…

Can color changes alter the neural correlates of recognition memory? Manipulation of processing affects an electrophysiological indicator of conceptual implicit memory.

Science.gov (United States)

Cui, Xiaoyu; Gao, Chuanji; Zhou, Jianshe; Guo, Chunyan

2016-09-28

It has been widely shown that recognition memory includes two distinct retrieval processes: familiarity and recollection. Many studies have shown that recognition memory can be facilitated when there is a perceptual match between the studied and the tested items. Most event-related potential studies have explored the perceptual match effect on familiarity on the basis of the hypothesis that the specific event-related potential component associated with familiarity is the FN400 (300-500 ms mid-frontal effect). However, it is currently unclear whether the FN400 indexes familiarity or conceptual implicit memory. In addition, on the basis of the findings of a previous study, the so-called perceptual manipulations in previous studies may also involve some conceptual alterations. Therefore, we sought to determine the influence of perceptual manipulation by color changes on recognition memory when the perceptual or the conceptual processes were emphasized. Specifically, different instructions (perceptually or conceptually oriented) were provided to the participants. The results showed that color changes may significantly affect overall recognition memory behaviorally and that congruent items were recognized with a higher accuracy rate than incongruent items in both tasks, but no corresponding neural changes were found. Despite the evident familiarity shown in the two tasks (the behavioral performance of recognition memory was much higher than at the chance level), the FN400 effect was found in conceptually oriented tasks, but not perceptually oriented tasks. It is thus highly interesting that the FN400 effect was not induced, although color manipulation of recognition memory was behaviorally shown, as seen in previous studies. Our findings of the FN400 effect for the conceptual but not perceptual condition support the explanation that the FN400 effect indexes conceptual implicit memory.

Conceptual model for dietary behaviour change at household level: a ‘best-fit’ qualitative study using primary data

Science.gov (United States)

2014-01-01

Background Interventions having a strong theoretical basis are more efficacious, providing a strong argument for incorporating theory into intervention planning. The objective of this study was to develop a conceptual model to facilitate the planning of dietary intervention strategies at the household level in rural Kerala. Methods Three focus group discussions and 17 individual interviews were conducted among men and women, aged between 23 and 75 years. An interview guide facilitated the process to understand: 1) feasibility and acceptability of a proposed dietary behaviour change intervention; 2) beliefs about foods, particularly fruits and vegetables; 3) decision-making in households with reference to food choices and access; and 4) to gain insights into the kind of intervention strategies that may be practical at community and household level. The data were analysed using a modified form of qualitative framework analysis, which combined both deductive and inductive reasoning. A priori themes were identified from relevant behaviour change theories using construct definitions, and used to index the meaning units identified from the primary qualitative data. In addition, new themes emerging from the data were included. The associations between the themes were mapped into four main factors and its components, which contributed to construction of the conceptual model. Results Thirteen of the a priori themes from three behaviour change theories (Trans-theoretical model, Health Belief model and Theory of Planned Behaviour) were confirmed or slightly modified, while four new themes emerged from the data. The conceptual model had four main factors and its components: impact factors (decisional balance, risk perception, attitude); change processes (action-oriented, cognitive); background factors (personal modifiers, societal norms); and overarching factors (accessibility, perceived needs and preferences), built around a three-stage change spiral (pre

Study progress on free radicals and graves disease

International Nuclear Information System (INIS)

Zhang Ruiguo; Jin Jianhua

2009-01-01

Free radical-mediated oxidative injury has been closely implicated in the occurrence and development of many diseases. Graves disease was also accompanied by changes of the free radicals, especially for reactive oxygen species and reactive nitrogen, et al, and the oxidative stress can cause a certain degree of injury on the thyroid and other human important organs. Antithyroid drug and 131 I treatment of Graves disease, the oxidative and antioxidative parameters can also be changed. (authors)

A conceptual framework to understand teachers’ Professional Dispositions and Orientation towards tablet technology in secondary schools

Directory of Open Access Journals (Sweden)

Suzanne Sackstein

2017-10-01

Full Text Available While recent technological innovations have resulted in calls to incorporate tablets into the classroom, schools have been criticised for not taking advantage of what the technology has to offer. Past research has shown that teachers do not automatically choose to adopt technology in the classroom. A number of concerns exist in relation to the research being conducted within this area. Firstly, the majority of research studies have not been based on sound conceptual frameworks. Secondly, for the most part, these research studies have tended to focus on the technology itself rather than the resulting changes in teaching and learning. Finally, much of the literature is premised on constructivist pedagogic practices which offer promissories of radical pedagogic change. An understanding of technology teachers’ orientations to the new technology, coupled with an understanding of the reasons behind teachers’ choices to adopt or not adopt technology has not yet been fully explored. From a review of the literature in relation to teachers’ Professional Dispositions, derived from the work of Bernstein on the pedagogic discourse, alongside Hooper and Rieber’s model on educational technology adoption a conceptual framework has been developed to will shed light on secondary school teachers’ differential adoption of tablet technology.

Conceptual framework for research on global change 1992-1995

International Nuclear Information System (INIS)

1992-04-01

For a better overall understanding of the Earth system scientists have initiated extensive international research programs dealing with the dynamics of the Earth system. These activities are characterized by their interdisciplinary, border crossing, and system orientated approach. For a long time scientists from the Federal Republic of Germany participate significantly in the conception and completion of such programs. The more and more urgent questions from politics and from the public have prompted the Federal Government under the leadership of the Federal Ministry for Research and Technology to increase these efforts. In this the Federal Government will also be supported by the Scientific Advisory Committee appointed by it, which annually presents a report on the state of global changes and their consequences. In this brochure the Conceptual Framework for Research on Global Changes is presented, which was passed by the Federal Cabinet in April 1992. It is documenting the advanced state of research, which has already been achieved in this country. At the same time, however, it is made clear that significant further steps have to be taken to contribute to the solution of the most urgent problems of the world. (orig.)

A conceptual framework for effectively anticipating water-quality changes resulting from changes in agricultural activities

Science.gov (United States)

Capel, Paul D.; Wolock, David M.; Coupe, Richard H.; Roth, Jason L.

2018-01-10

Agricultural activities can affect water quality and the health of aquatic ecosystems; many water-quality issues originate with the movement of water, agricultural chemicals, and eroded soil from agricultural areas to streams and groundwater. Most agricultural activities are designed to sustain or increase crop production, while some are designed to protect soil and water resources. Numerous soil- and water-protection practices are designed to reduce the volume and velocity of runoff and increase infiltration. This report presents a conceptual framework that combines generalized concepts on the movement of water, the environmental behavior of chemicals and eroded soil, and the designed functions of various agricultural activities, as they relate to hydrology, to create attainable expectations for the protection of—with the goal of improving—water quality through changes in an agricultural activity.The framework presented uses two types of decision trees to guide decision making toward attainable expectations regarding the effectiveness of changing agricultural activities to protect and improve water quality in streams. One decision tree organizes decision making by considering the hydrologic setting and chemical behaviors, largely at the field scale. This decision tree can help determine which agricultural activities could effectively protect and improve water quality in a stream from the movement of chemicals, or sediment, from a field. The second decision tree is a chemical fate accounting tree. This decision tree helps set attainable expectations for the permanent removal of sediment, elements, and organic chemicals—such as herbicides and insecticides—through trapping or conservation tillage practices. Collectively, this conceptual framework consolidates diverse hydrologic settings, chemicals, and agricultural activities into a single, broad context that can be used to set attainable expectations for agricultural activities. This framework also enables

Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor.

Science.gov (United States)

El-Agamey, Ali; McGarvey, David J

2016-01-01

The reactions of acetylperoxyl radicals with different carotenoids (7,7'-dihydro-β-carotene and ζ-carotene) in SDS and CTAC microemulsions of different compositions were investigated using laser flash photolysis (LFP) coupled with kinetic absorption spectroscopy. The primary objective of this study was to explore the influence of microemulsion composition and the type of surfactant used on the yields and kinetics of various transients formed from the reaction of acetylperoxyl radicals with carotenoids. Also, the influence of the site (hydrocarbon phases or aqueous phase) of generation of the peroxyl radical precursor was examined by using 4-acetyl-4-phenylpiperidine hydrochloride (APPHCl) and 1,1-diphenylacetone (11DPA) as water-soluble and lipid-soluble peroxyl radical precursors, respectively. LFP of peroxyl radical precursors with 7,7'-dihydro-β-carotene (77DH) in different microemulsions gives rise to the formation of three distinct transients namely addition radical (λmax=460 nm), near infrared transient1 (NIR, λmax=700 nm) and 7,7'-dihydro-β-carotene radical cation (77DH(•+), λmax=770 nm). In addition, for ζ-carotene (ZETA) two transients (near infrared transient1 (NIR1, λmax=660 nm) and ζ-carotene radical cation (ZETA(•+), λmax=730-740 nm)) are generated following LFP of peroxyl radical precursors in the presence of ζ-carotene (ZETA) in different microemulsions. The results show that the composition of the microemulsion strongly influences the observed yield and kinetics of the transients formed from the reactions of peroxyl radicals (acetylperoxyl radicals) with carotenoids (77DH and ZETA). Also, the type of surfactant used in the microemulsions influences the yield of the transients formed. The dependence of the transient yields and kinetics on microemulsion composition (or the type of surfactant used in the microemulsion) can be attributed to the change of the polarity of the microenvironment of the carotenoid. Furthermore, the nature of

Climate change and radical energy innovation: the policy issues

Energy Technology Data Exchange (ETDEWEB)

Smith, Keith

2009-01-15

How can we sustain global economic performance while reducing and perhaps eliminating climate impacts? This dual objective ultimately requires the innovation of radically new low- or zero-emitting energy technologies. But what is involved in such innovation, and why and how should governments support it? What are the implications for innovation policy makers? The paper discusses the nature of the innovation challenge of climate change, develops a framework for analyzing modes of innovation, applies the framework to energy technologies and analyses policies for energy innovation. The overall argument is that we are 'locked in' to an unsustainable but large-scale hydrocarbon energy system. The innovation problem is to develop alternatives to this system as a whole. Yet despite widespread environmental innovation efforts and incentives, these are not yet addressing the innovation challenge on an adequate scale. The analytical framework sees technologies not as single techniques but as multi-faceted technological 'regimes'. Technological regimes comprise production systems and methods, scientific and engineering knowledge organization, infrastructures, and social patterns of technology use. We live not with individual energy technologies but with a complex hydrocarbon regime. Against this background we can identify three modes of innovation, with very different characteristics. They are; Incremental innovations - upgrades to existing technologies, producing innovation within existing technological regimes, such as increases in the capabilities and speeds of microprocessors; Disruptive innovations - new methods of performing existing technical functions, changing how things are done, but not changing the overall regime, such as the shift from film to digital imaging; Radical innovations - technological regime shifts, involving wholly new technical functions, new knowledge bases, and new organizational forms, such as the transition from steam power

Hydroxyl-radical induced dechlorination of pentachlorophenol in water

International Nuclear Information System (INIS)

He Yongke; Wu Jilan; Fang Xingwang; Sonntag, C. von

1998-01-01

The hydroxyl-radical induced dechlorination of pentachlorophenol (PCP) in water has been investigated pulse radiolytically. Hydroxyl radicals react with PCP by both electron transfer and addition. The former process results in pentachlorophenoxyl radicals (PCP-O), the latter process followed by rapid HCl elimination gives birth to deprotonated hydroxytetrachlorophenoxyl radicals ( - O-TCP-O). These phenoxyl radicals exhibit maximum absorption around 452 nm, which hinders the proper estimation of the ratio of the two processes. However, these two processes cause different changes in conductivity. In basic solution, the electron transfer causes a conductivity increase due to the formation of OH - whereas an addition followed by HCl elimination results in a conductivity decrease. The concurrence of these two processes reduces the relative variation in conductivity, from which about 53% electron transfer is deduced

Even free radicals should follow some rules: a guide to free radical research terminology and methodology.

Science.gov (United States)

Forman, Henry Jay; Augusto, Ohara; Brigelius-Flohe, Regina; Dennery, Phyllis A; Kalyanaraman, Balaraman; Ischiropoulos, Harry; Mann, Giovanni E; Radi, Rafael; Roberts, L Jackson; Vina, Jose; Davies, Kelvin J A

2015-01-01

Free radicals and oxidants are now implicated in physiological responses and in several diseases. Given the wide range of expertise of free radical researchers, application of the greater understanding of chemistry has not been uniformly applied to biological studies. We suggest that some widely used methodologies and terminologies hamper progress and need to be addressed. We make the case for abandonment and judicious use of several methods and terms and suggest practical and viable alternatives. These changes are suggested in four areas: use of fluorescent dyes to identify and quantify reactive species, methods for measurement of lipid peroxidation in complex biological systems, claims of antioxidants as radical scavengers, and use of the terms for reactive species. Copyright © 2014 Elsevier Inc. All rights reserved.

Providing Context for Complexity: Using Infographics and Conceptual Models to Teach Global Change Processes

Science.gov (United States)

Bean, J. R.; White, L. D.

2015-12-01

Understanding modern and historical global changes requires interdisciplinary knowledge of the physical and life sciences. The Understanding Global Change website from the UC Museum of Paleontology will use a focal infographic that unifies diverse content often taught in separate K-12 science units. This visualization tool provides scientists with a structure for presenting research within the broad context of global change, and supports educators with a framework for teaching and assessing student understanding of complex global change processes. This new approach to teaching the science of global change is currently being piloted and refined based on feedback from educators and scientists in anticipation of a 2016 website launch. Global change concepts are categorized within the infographic as causes of global change (e.g., burning of fossil fuels, volcanism), ongoing Earth system processes (e.g., ocean circulation, the greenhouse effect), and the changes scientists measure in Earth's physical and biological systems (e.g., temperature, extinctions/radiations). The infographic will appear on all website content pages and provides a template for the creation of flowcharts, which are conceptual models that allow teachers and students to visualize the interdependencies and feedbacks among processes in the atmosphere, hydrosphere, biosphere, and geosphere. The development of this resource is timely given that the newly adopted Next Generation Science Standards emphasize cross-cutting concepts, including model building, and Earth system science. Flowchart activities will be available on the website to scaffold inquiry-based lessons, determine student preconceptions, and assess student content knowledge. The infographic has already served as a learning and evaluation tool during professional development workshops at UC Berkeley, Stanford University, and the Smithsonian National Museum of Natural History. At these workshops, scientists and educators used the infographic

The Interactions between Problem Solving and Conceptual Change: System Dynamic Modelling as a Platform for Learning

Science.gov (United States)

Lee, Chwee Beng

2010-01-01

This study examines the interactions between problem solving and conceptual change in an elementary science class where students build system dynamic models as a form of problem representations. Through mostly qualitative findings, we illustrate the interplay of three emerging intervening conditions (epistemological belief, structural knowledge…

Enhancing Eight Grade Students' Scientific Conceptual Change and Scientific Reasoning through a Web-Based Learning Program

Science.gov (United States)

Liao, Ya-Wen; She, Hsiao-Ching

2009-01-01

This study reports the impacts of the Scientific Concept Construction and Reconstruction (SCCR) digital learning system on eighth grade students' concept construction, conceptual change, and scientific reasoning involving the topic of "atoms". A two-factorial experimental design was carried out to investigate the effects of the approach…

Experiential learning and cognitive tools: The impact of simulations on conceptual change in continuing healthcare education

NARCIS (Netherlands)

Reeves, Thomas; Reeves, Patricia; McKenney, Susan

2014-01-01

Reeves, T. C., Reeves, P. M., & McKenney, S. (2013). Experiential learning and cognitive tools: The impact of simulations on conceptual change in continuing healthcare education. In J. M. Spector, B. B. Lockee, S. E. Smaldino, & M. Herring (eds.), Learning, problem solving, and mindtools: Essays in

Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence

DEFF Research Database (Denmark)

Hammerum, Steen

2009-01-01

Spectroscopic, energetic and structural information obtained by DFT and G3-type computational studies demonstrates that charged proton donors can form moderately strong hydrogen bonds to simple alkyl radicals. The presence of these bonds stabilizes the adducts and modifies their structure......, and gives rise to pronounced shifts of IR stretching frequencies and to increased absorption intensities. The hydrogen bond acceptor properties of alkyl radicals equal those of many conventional acceptors, e.g., the bond length changes and IR red-shifts suggest that tert-butyl radicals are slightly better...... acceptors than formaldehyde molecules, while propyl radicals are as good as H2O. The hydrogen bond strength appears to depend on the proton affinity of the proton donor and on the ionization energy of the acceptor alkyl radical, not on the donor-acceptor proton affinity difference, reflecting...

Hydroxyl-radical-induced oxidation of cyclic dipeptides: Reactions of free peptide radicals and their peroxyl radicals

International Nuclear Information System (INIS)

Mieden, O.J.

1989-01-01

In the course of this study investigations were carried out into the reactions of hydroxyl radicals and hydrogen atoms with cyclic dipeptides as well as the subsequent reactions of peptide radicals and their peroxyl radicals in aqueous solution. The radiolysis products formed in the absence and presence of oxygen or transient metal complexes were characterized and determined on a quantitative basis. The linking of information from product analyses to the kinetic data for transient species obtained by time-resolving UV/VIS and conductivity measurements (pulse radiolysis) as well as computer-assisted simulations of individual events during the reaction permitted an evaluation of the mechanisms underlying the various processes and an identification of interim products with short life-times, which did or did not belong to the group of radicals. Through the characterization of key reactions of radicals and peroxyl radicals of this substance class a major advance has been made towards a better understanding of the role of radicals in the peptide compound and the mechanisms involved in indirect radiation effects on long-chain peptides and proteins. (orig.) [de

Transnational Islamic activism and radicalization : patterns, trends, and prognosticators.

Energy Technology Data Exchange (ETDEWEB)

Colbaugh, Richard; Engi, Dennis; LaViolette, Randall A.; Spomer, Judith E.

2010-06-01

The research described in this report developed the theoretical and conceptual framework for understanding, recognizing, and anticipating the origins, dynamic mechanisms, perceptions, and social structures of Islamic social reform movements in the Muslim homeland and in diaspora communities. This research has revealed valuable insights into the dynamic mechanisms associated with reform movements and, as such, offers the potential to provide indications and warnings of impending violence. This study produced the following significant findings: (1) A framework for understanding Islamic radicalization in the context of Social Movement Theory was developed and implemented. This framework provides a causal structure for the interrelationships among the myriad features of a social movement. (2) The degree to which movement-related activity shows early diffusion across multiple social contexts is a powerful distinguisher of successful and unsuccessful social movements. Indeed, this measurable appears to have significantly more predictive power than volume of such activity and also more power than various system intrinsics. (3) Significant social movements can occur only if both the intra-context 'infectivity' of the movement exceeds a certain threshold and the inter-context interactions associated with the movement occur with a frequency that is larger than another threshold. Note that this is reminiscent of, and significantly extends, well-known results for epidemic thresholds in disease propagation models. (4) More in-depth content analysis of blogs through the lens of Argumentation Theory has the potential to reveal new insights into radicalization in the context of Social Movement Theory. This connection has the potential to be of value from two important perspectives - first, this connection has the potential to provide more in depth insights into the forces underlying the emergence of radical behavior and second, this connection may provide insights into

Penile rehabilitation after radical prostatectomy

DEFF Research Database (Denmark)

Fode, Mikkel; Ohl, Dana A; Ralph, David

2013-01-01

The pathophysiology of erectile dysfunction after radical prostatectomy (RP) is believed to include neuropraxia, which leads to temporarily reduced oxygenation and subsequent structural changes in penile tissue. This results in veno-occlusive dysfunction, therefore, penile rehabilitation programmes...

A radical approach to radical innovation

NARCIS (Netherlands)

D. Deichmann (Dirk); J.C.M. van den Ende (Jan)

2014-01-01

textabstractInnovation pays. Amazon, Apple, Facebook, Google – nearly every one of today’s most successful companies has a talent for developing radical new ideas. But how best to encourage radical initiative taking from employees, and does their previous success or failure at it play a role?

Studies of initial stage in coal liquefaction. 4. Radical formation and structural change with thermal decomposition of coal; Ekika hanno no shoki katei ni kansuru kenkyu. 4. Netsubunkai ni tomonau radical seisei kyodo to kozo henka

Energy Technology Data Exchange (ETDEWEB)

Kanaji, M.; Kaneko, T.; Shimasaki, K. [Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan); Kumagai, H.; Chiba, T. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

1996-10-28

In relation to coal liquefaction reaction, the effect of the coexistence of transferable hydrogen (TH) from process solvent on reduction of radical concentration and the effect of pre-heat treatment on average structure of coals were studied. In experiment, change in radical concentration with temperature rise was measured using the system composed of Yallourn coal and process solvent. The results are as follows. Process solvent with a wide boiling point range of 180-420{degree}C is effective in suppressing an increase in radical concentration even at higher temperature. The effect of hydrogen-donating solvent increases with TH. It was also suggested that high-boiling point constituents in solvent stabilize radicals even over 400{degree}C by vapor phase hydrogenation. The experimental results of pre-heat treatment are as follows. Although the conversion improvement effect of TH is equivalent to that of the model solvent, TH tends to produce soluble products with smaller ring numbers. It was thus suggested that pre-heat treatment in process solvent is effective to inhibit retrogressive reactions. 6 refs., 5 figs., 1 tab.

Conceptual Changes to the Definition of Borderline Personality Disorder Proposed for DSM-5

Science.gov (United States)

Samuel, Douglas B.; Widiger, Thomas A.; Pilkonis, Paul A.; Miller, Joshua D.; Lynam, Donald R.; Ball, Samuel A.

2013-01-01

The Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 Personality and Personality Disorders Work Group proposed the elimination of diagnostic criterion sets in favor of a prototype matching system that defines personality disorders using narrative descriptions. Although some research supports this general approach, no empirical studies have yet examined the specific definitions proposed for DSM–5. Given the wide interest in borderline personality disorder (BPD), it is crucial to determine how this methodological shift might affect the content and conceptualization of the diagnosis. Eighty-two experts on BPD provided ratings of the DSM–IV–TR or DSM–5 version of BPD in terms of 37 traits proposed for DSM–5. Analyses revealed significant and meaningful differences among the two constructs, with the DSM–5 version evincing increased interpersonal dependency but a decreased emphasis on antagonism and disinhibition. A second study within a clinical sample demonstrated that both antagonism and disinhibition mediated the relationships between DSM–IV BPD and impairment, suggesting that the proposed changes might have important consequences for BPD’s coverage, prevalence, and nomological network. More globally, our results illustrate that unanticipated shifts in diagnostic constructs can stem from seemingly minor revisions and suggest that research is needed to understand how these, or other changes, might affect our conceptualization, diagnosis, and treatment of BPD. PMID:21875165

Metaconceptually-Enhanced Simulation-Based Inquiry: Effects on Eighth Grade Students' Conceptual Change and Science Epistemic Beliefs

Science.gov (United States)

Huang, Kun; Ge, Xun; Eseryel, Deniz

2017-01-01

This study investigated the effects of metaconceptually-enhanced, simulation-based inquiry learning on eighth grade students' conceptual change in science and their development of science epistemic beliefs. Two experimental groups studied the topics of motion and force using the same computer simulations but with different simulation guides: one…

Radicalization In Pakistan And The Spread Of Radical Islam In Pakistan

Directory of Open Access Journals (Sweden)

Bahir ahmad

2015-08-01

Full Text Available ABSTRACT It is pertinent to mention that radicalism is not intrinsic to Islam and radical interpretations of the religion or for that matter may occur within any way of life and religion Saikal 2003 and yet the question remains as to why Muslims in certain geographical regions have more radical approaches towards their religion and also that what are the causes of such radicalization. Becoming a radical Muslim is not even a matter of a day nor is it a sudden process. There are several reasons behind making a person radical peaceful angry smiling or tolerant. For knowing the reason behind radicalization or radicals persons one has to understand the causes. Tracing these causes is one of the ways to eliminate such behavior. The first step in the elimination of the radical sentiments in a person is to develop peace in his personality Fair Malhotra amp Shapiro 2010. The chapter which has been addressed here is going to shed light on the roots and symptoms of the radicalism. There will be a brief discussion on how the roots of radicalism can be traced and can be eliminated. The assessment and discussion will be conducted on the parameters of the economy media politics and theology from social cultural point of view. According to the analysis of Ahrari 2000 political factor is one of the major and direct factors which have resulted in causing of the radicalism. These factors however intertwine with one another. Radical actions cannot take place only because of the political factors.

Allylthioketone Mediated Free Radical Polymerization of Methacrylates

Directory of Open Access Journals (Sweden)

Feng Zhong

2017-11-01

Full Text Available By combination of high trapping free radical efficiency of the thioketone and resonance of the allylic radical, a new type of mediating agent, 1,3,3-triphenylprop-2-ene-1-thione (TPPT has been successfully synthesized, and then is used to study controlled free radical polymerization of methacrylates. Very stable TPPT radicals at the end of poly(methyl methacrylate (PMMA are detected in the polymerization of MMA using TPPT and AIBN as the control agent and initiator. The MALDI-TOF MS spectra are used to identify terminal groups of the resultant poly(glycidyl methacrylate (PGMA, and major component of the obtained polymer has the structure, (CH32(CNC-PGMA-C7H9O3. Chain extension reaction tests ascertain formation of the dead polymers during the polymer storage and purification process of the polymers. Owing to very slow fragmentation reaction of the TPPT-terminated polymethacrylate radical and addition reaction of this radical with a primary radical, the growing chain radicals are difficult to be regenerated, leading to an unobvious change of the molecular weight with monomer conversion. The molecular weights of polymers can be controlled by the ratios of monomer/initiator and TPPT/initiator. However, the first order kinetics of the polymerization and the polymers with narrow polydispersity are obtained, and these phenomena are discussed. This study provides useful information on how to design a better controlling agent.

Carbonate radical anion-induced electron transfer in bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Joshi, Ravi [Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: rjudrin@yahoo.com; Mukherjee, T. [Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2006-07-15

Reaction of native and thermally denatured bovine serum albumin (BSA) with carbonate radical anion (CO{sub 3}{sup -} radical) has been studied using pulse radiolysis technique. Scavenging of CO{sub 3}{sup -} radical by native BSA and consequent electron transfer from tyrosine to tryptophan radical has been observed to occur with almost same rate constant (k{approx}1.7x10{sup 8} dm{sup 3} mol{sup -1} s{sup -1}) at pH 8.8. Effect of structural changes, due to thermal denaturation, on scavenging of CO{sub 3}{sup -} radical and the electron transfer process have been studied and discussed in this paper.

Conceptual understanding of climate change with a globally resolved energy balance model

Energy Technology Data Exchange (ETDEWEB)

Dommenget, Dietmar [Monash University, School of Mathematical Sciences, Melbourne, VIC (Australia); Floeter, Janine [Leibniz Institute for Marine Sciences, Kiel (Germany)

2011-12-15

The future climate change projections are essentially based on coupled general circulation model (CGCM) simulations, which give a distinct global warming pattern with arctic winter amplification, an equilibrium land-sea warming contrast and an inter-hemispheric warming gradient. While these simulations are the most important tool of the Intergovernmental Panel on Climate Change (IPCC) predictions, the conceptual understanding of these predicted structures of climate change and the causes of their uncertainties is very difficult to reach if only based on these highly complex CGCM simulations. In the study presented here we will introduce a very simple, globally resolved energy balance (GREB) model, which is capable of simulating the main characteristics of global warming. The model shall give a bridge between the strongly simplified energy balance models and the fully coupled 4-dimensional complex CGCMs. It provides a fast tool for the conceptual understanding and development of hypotheses for climate change studies, which shall build a basis or starting point for more detailed studies of observations and CGCM simulations. It is based on the surface energy balance by very simple representations of solar and thermal radiation, the atmospheric hydrological cycle, sensible turbulent heat flux, transport by the mean atmospheric circulation and heat exchange with the deeper ocean. Despite some limitations in the representations of the basic processes, the models climate sensitivity and the spatial structure of the warming pattern are within the uncertainties of the IPCC models simulations. It is capable of simulating aspects of the arctic winter amplification, the equilibrium land-sea warming contrast and the inter-hemispheric warming gradient with good agreement to the IPCC models in amplitude and structure. The results give some insight into the understanding of the land-sea contrast and the polar amplification. The GREB model suggests that the regional inhomogeneous

A Scale-Explicit Framework for Conceptualizing the Environmental Impacts of Agricultural Land Use Changes

Directory of Open Access Journals (Sweden)

Iago Lowe Hale

2014-11-01

Full Text Available Demand for locally-produced food is growing in areas outside traditionally dominant agricultural regions due to concerns over food safety, quality, and sovereignty; rural livelihoods; and environmental integrity. Strategies for meeting this demand rely upon agricultural land use change, in various forms of either intensification or extensification (converting non-agricultural land, including native landforms, to agricultural use. The nature and extent of the impacts of these changes on non-food-provisioning ecosystem services are determined by a complex suite of scale-dependent interactions among farming practices, site-specific characteristics, and the ecosystem services under consideration. Ecosystem modeling strategies which honor such complexity are often impenetrable by non-experts, resulting in a prevalent conceptual gap between ecosystem sciences and the field of sustainable agriculture. Referencing heavily forested New England as an example, we present a conceptual framework designed to synthesize and convey understanding of the scale- and landscape-dependent nature of the relationship between agriculture and various ecosystem services. By accounting for the total impact of multiple disturbances across a landscape while considering the effects of scale, the framework is intended to stimulate and support the collaborative efforts of land managers, scientists, citizen stakeholders, and policy makers as they address the challenges of expanding local agriculture.

The Collaboration of Cooperative Learning and Conceptual Change: Enhancing the Students' Understanding of Chemical Bonding Concepts

Science.gov (United States)

Eymur, Gülüzar; Geban, Ömer

2017-01-01

The main purpose of this study was to investigate the effects of cooperative learning based on conceptual change approach instruction on ninth-grade students' understanding in chemical bonding concepts compared to traditional instruction. Seventy-two ninth-grade students from two intact chemistry classes taught by the same teacher in a public high…

Psychopathology according to behaviorism: a radical restatement.

Science.gov (United States)

Pérez-Alvarez, Marino

2004-11-01

This article is a radical restatement of the predominant psychopathology, which is characterized by nosological systems and by its approach towards a neurobiological conception of the so-called mental disorders. The "radical" sense of this restatement is that of radical behaviorism itself. As readers will recall, "radical" applied to behaviorism means total (not ignoring anything that interests psychology), pragmatic (referring to the practical sense of knowledge), and it also derives from the Latin word for "root" (and thus implies change beginning at a system's roots or getting to the root of things, in this case, of psychological disorders). Based on this, I introduce the Aristotelian distinction of material and form, which, besides being behaviorist avant la lettre, is used here as a critical instrument to unmask the hoax of psychopathology as it is presented. The implications of this restatement are discussed, some of them already prepared for clinical practice.

Role of free radicals in radiation chemical aging

Energy Technology Data Exchange (ETDEWEB)

Greenstock, C L

1986-01-01

Ionizing radiation initiates chemical changes in DNA, phospholipid membranes and other critical cell targets, that, if allowed to accumulate unrepaired, may lead to aging and other chronic effects. The chemical effects are free radical mediated, the principal damaging species being radical OH and to a lesser extent O2-anion radical and the molecular product H/sub 2/O/sub 2/. Many compounds can act in combination with ionizing radiation, to amplify the potential oxidative stress. Chemicals, ultra-violet light, lipid peroxides and their breakdown products may increase the extent of acute and chronic radiobiological effects.

Combining Different Conceptual Change Methods within Four-Step Constructivist Teaching Model: A Sample Teaching of Series and Parallel Circuits

Science.gov (United States)

Ipek, Hava; Calik, Muammer

2008-01-01

Based on students' alternative conceptions of the topics "electric circuits", "electric charge flows within an electric circuit", "how the brightness of bulbs and the resistance changes in series and parallel circuits", the current study aims to present a combination of different conceptual change methods within a four-step constructivist teaching…

Manipulating radicals: Using cobalt to steer radical reactions

OpenAIRE

Chirilă, A.

2017-01-01

This thesis describes research aimed at understanding and exploiting metallo-radical reactivity and explores reactions mediated by square planar, low-spin cobalt(II) complexes. A primary goal was to uncover novel reactivity of discrete cobalt(III)-bound carbene radicals generated upon reaction of the cobalt(II) catalysts with carbene precursors. Another important goal was to replace cobalt(II)-porphyrin catalysts with cheaper and easier to prepare metallo-radical analogues. Therefore the cata...

Is there any change in pelvic floor electromyography during the first 6 months after radical retropubic prostatectomy?

Science.gov (United States)

Hacad, Claudia R; Glazer, Howard I; Zambon, João Paulo C; Burti, Juliana S; Almeida, Fernando G

2015-03-01

The aim of this study is to determine electromyographic pelvic floor muscles activity during the first 6 months post RRP and its relationship to urinary continence. Thirty-eight men (mean age of 63.1 ± 5.7 year) with prostate cancer scheduled for open radical retropubic prostatectomy were evaluated. pelvic radiotherapy, systemic or neurologic diseases, pre-operative International Prostate Symptoms Score (IPSS) >7 and OABq ≥8. Surface electromyography (sEMG) evaluation, IPSS, Urinary Distress Inventory, Incontinence Impact Questionnaire, and Overactive Bladder Questionnaire-short form were applied before and at 1, 3, and 6 months after RRP. Six months after surgery, 18 men (47.4 %) presented urinary leakage. The sEMG evaluations within the first 6 months presented changes in fast contraction amplitude (p = 0.006), rest amplitude after fast contraction (p = 0.04), 10 s sustained contraction mean amplitude (p = 0.024) and final rest amplitude (p = 0.011). We observed that continent and incontinent patients as a group presented electromyographic changes during the first 6 months after radical prostatectomy that could be justified by the denervation/reinnervation of the external urethral sphincter. This finding is consistent with the adaptation of the pelvic floor musculature to the new urethral sphincter condition following surgery.

Free radical inactivation of trypsin

International Nuclear Information System (INIS)

Cudina, Ivana; Jovanovic, S.V.

1988-01-01

Reactivities of free radical oxidants, radical OH, Br2-anion radical and Cl 3 COO radical and a reductant, CO2-anion radical, with trypsin and reactive protein components were determined by pulse radiolysis of aqueous solutions at pH 7, 20 0 C. Highly reactive free radicals, radical OH, Br2-anion radical and CO2-anion radical, react with trypsin at diffusion controlled rates. Moderately reactive trichloroperoxy radical, k(Cl 3 COO radical + trypsin) preferentially oxidizes histidine residues. The efficiency of inactivation of trypsin by free radicals is inversely proportional to their reactivity. The yields of inactivation of trypsin by radical OH, Br2-anion radical and CO2-anion radical are low, G(inactivation) = 0.6-0.8, which corresponds to ∼ 10% of the initially produced radicals. In contrast, Cl 3 COO radical inactivates trypsin with ∼ 50% efficiency, i.e. G(inactivation) = 3.2. (author)

The Effect of Group Works and Demonstrative Experiments Based on Conceptual Change Approach: Photosynthesis and Respiration

Science.gov (United States)

Cibik, Ayse Sert; Diken, Emine Hatun; Darcin, Emine Selcen

2008-01-01

The purpose of this study is to investigate the effect of the use of group works and demonstration experiments based on conceptual change approach in the elimination of misconception about the subject of photosynthesis and respiration in plants in pre-service science teachers. This study was conducted with 78 pre-service science teachers including…

The Effectiveness of Conceptual Change Texts in Remediating High School Students' Alternative Conceptions Concerning Chemical Equilibrium

Science.gov (United States)

Ozmen, Haluk

2007-01-01

This study investigated the effectiveness of conceptual change texts in remediating high school students' alternative conceptions concerning chemical equilibrium. A quasi-experimental design was used in this study. The subjects for this study consisted of a total 78 tenth-grade students, 38 of them in the experimental group and 40 of them in the…

How Students' Epistemological Beliefs in the Domain of Physics and Their Conceptual Change Are Related?

Science.gov (United States)

Kaymak, Ercan; Ogan-Bekiroglu, Feral

2013-01-01

The purposes of this study were to determine high school students' epistemological beliefs in the domain of physics and to explore and explain the possible relationship between their beliefs and their conceptual change in physics by taking the students' learning strategies into account. A multi-case study design was used for the research…

Excimer laser corneal surgery and free oxygen radicals.

Science.gov (United States)

Bilgihan, K; Bilgihan, A; Akata, F; Hasanreisoğlu, B; Türközkan, N

1996-01-01

Corneal photoablation with 193 nm argon fluoride excimer laser is a new technique for the treatment of refractive errors and for removing corneal opacities and irregularities. Ultraviolet radiation and thermal injury induce free radical formation in the tissues. The aim of this study was to confirm the production of free radicals by excimer laser photoablation in rabbits. The thermal changes of the posterior corneal surface were recorded during excimer laser photoablation. The lipid peroxide (LPO) levels and superoxide dismutase (SOD) activities of aqueous humour were measured after excimer laser keratectomy. The aqueous LPO levels were not changed after excimer laser ablation, but both the thermal increase in the cornea during the photoablation and the decreased aqueous SOD activities suggest that free radicals are formed in the cornea during excimer laser keratectomy, and that they may be responsible for some of the complications of excimer laser corneal surgery.

Exploring the Theories of Radicalization

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Maskaliūnaitė Asta

2015-12-01

Full Text Available After the London bombings in July 2005, the concern of terrorism scholars and policy makers has turned to “home-grown” terrorism and potential for political violence from within the states. “Radicalization” became a new buzz word. This article follows a number of reviews of the literature on radicalization and offers another angle for looking at this research. First, it discusses the term “radicalization” and suggests the use of the following definition of radicalization as a process by which a person adopts belief systems which justify the use of violence to effect social change and comes to actively support as well as employ violent means for political purposes. Next, it proposes to see the theories of radicalization focusing on the individual and the two dimensions of his/her motivation: whether that motivation is internal or external and whether it is due to personal choice or either internal (due to some psychological traits or external compulsion. Though not all theories fall neatly within these categories, they make it possible to make comparisons of contributions from a variety of different areas thus reflecting on the interdisciplinary nature of the study of terrorism in general and radicalization as a part of it.

Radicals of DNA and DNA nucleotides generated by ionising radiation

International Nuclear Information System (INIS)

Przybytniak, G.

2004-01-01

A first stage of cell processes leading to DNA damage of initiated by radical reactions. In a model system such transformations were generated by ionising radiation which involves production of electron loss and electron gain centers of the substrate and radical formation. Using cryogenic ESR spectroscopy it was found that the DNA nucleotides, which convert to radical anions upon electron capture undergo the separation of unpaired spin and charge due to protonation. Circular and linear dichroism studies enabled to conclude that iron ions(III) induce strong changes in the DNA helical structure indicating their coordination with nitrogen bases. The repair of DNA radicals produced via radiolytic oxidation, i.e. the guanine radical cation and the allyl type radical of thymine, is possible at elevated temperatures due to the involvement of sulphydryl groups. The influence of the thiol charge is then limited

Complex Dynamic Systems View on Conceptual Change: How a Picture of Students' Intuitive Conceptions Accrue from Dynamically Robust Task Dependent Learning Outcomes

Science.gov (United States)

Koponen, Ismo T.; Kokkonen, Tommi; Nousiainen, Maiji

2017-01-01

We discuss here conceptual change and the formation of robust learning outcomes from the viewpoint of complex dynamic systems (CDS). The CDS view considers students' conceptions as context dependent and multifaceted structures which depend on the context of their application. In the CDS view the conceptual patterns (i.e. intuitive conceptions…

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes.

Science.gov (United States)

Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

2015-09-15

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (td,E) and hydroxyl-radical oxidation half-lives (tOH,E) in sunlit surface waters. The td,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas tOH,E ranges from 3.24h to 33.6h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. Copyright © 2015. Published by Elsevier B.V.

Students' Conceptual Change in Electricity and Magnetism Using Simulations: A Comparison of Cognitive Perturbation and Cognitive Conflict

Science.gov (United States)

Dega, Bekele Gashe; Kriek, Jeanne; Mogese, Temesgen Fereja

2013-01-01

The purpose of this study was to investigate Ethiopian physics undergraduate students' conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). A quasi-experimental design was used to study the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive…

X-band ESR study on evaluation of radicals induced in pasteurized pepper

International Nuclear Information System (INIS)

Matsuura, Masaaki; Ogawa, Satoko; Ukai, Mitsuko; Oowada, Shigeru

2007-01-01

The radical properties of pasteurized pepper were investigated by means of X-band ESR spectroscopy. Pasteurization process was done by irradiation or steam. There were three radicals in the specimens before and after pasteurization. Upon irradiation a new radical was found. ESR peak intensity of specimen before and after parturition with steam was almost same level. Peak intensity of radiated pepper showed almost 4 times as compare with that of non treated pepper. Radical activity of the specimens after pasteurization showed almost same value. We concluded that radicals were induced by irradiation. But the radical activity was not changed before and after pasteurization. (author)

EVALUATION OF CONCEPTUAL FRAMEWORKS IN ASTRONOMY

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David Pundak

2016-02-01

Full Text Available Even though astronomy is the oldest science, it is still an open question how to evaluate students’ understanding in astronomy. In spite of the fact that some methods and evaluation tools have been developed for that purpose, the sources of students' difficulties in astronomy are still unclear. This paper presents an investigation of the changes in conceptual frameworks in astronomy among 50 engineering students as a result of learning a general course in astronomy. A special tool called Conceptual Frameworks in Astronomy (CFA, which was initially used in 1989, was adopted to gather data for the present research. In its new version, the tool includes 23 questions and five to six optional answers to each question. Each of the answers characterizes one of the four conceptual frameworks: pre-scientific, geocentric, heliocentric and sidereal. These four conceptual frameworks act as a taxonomical system that enables us to evaluate astronomical understanding. The paper describes the background of the CFA, its development, and discusses its validity and reliability. Using the CFA we were able to: (1 identify the students’ conceptual frameworks at the beginning of the course and at its end, (2 to evaluate the students’ paradigmatic change following the course. It was found that the measure of the students’ improvement (gain index was g = 0.37. Approximately 45% of the students in the course improved their conceptual frameworks in astronomy and 26% deepened their understanding of the heliocentric or sidereal conceptual frameworks. The CFA can also be applied as an evaluation tool in all schools and institutions that teach astronomy.

Exercise redox biochemistry: Conceptual, methodological and technical recommendations

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James N. Cobley

2017-08-01

Full Text Available Exercise redox biochemistry is of considerable interest owing to its translational value in health and disease. However, unaddressed conceptual, methodological and technical issues complicate attempts to unravel how exercise alters redox homeostasis in health and disease. Conceptual issues relate to misunderstandings that arise when the chemical heterogeneity of redox biology is disregarded: which often complicates attempts to use redox-active compounds and assess redox signalling. Further, that oxidised macromolecule adduct levels reflect formation and repair is seldom considered. Methodological and technical issues relate to the use of out-dated assays and/or inappropriate sample preparation techniques that confound biochemical redox analysis. After considering each of the aforementioned issues, we outline how each issue can be resolved and provide a unifying set of recommendations. We specifically recommend that investigators: consider chemical heterogeneity, use redox-active compounds judiciously, abandon flawed assays, carefully prepare samples and assay buffers, consider repair/metabolism, use multiple biomarkers to assess oxidative damage and redox signalling. Keywords: Exercise, Oxidative stress, Free radical, Antioxidants, Redox signalling

Do You Believe in Magic? Exploring the Conceptualization of Augmented Reality and its Implications for the User in the Field of Library and Information Science

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Elizabeth Zak

2014-12-01

Full Text Available Augmented reality technology has implications for the ways that the field of library and information science (LIS serves users and organizes information. Through content analysis, the author examined how augmented reality (AR is conceptualized within a sample of LIS literature from the Library and Information Science and Technology Abstracts (LISTA database and Google Blogs postings, and whether Radical Change Theory (RCT and the digital age principles of interactivity, connectivity and access are present in the discussion of this technology. The analysis of data led to the identification of 14 categories comprised of 132 total codes across sources within the data set.  The analysis indicates that the conceptualization of AR, while inconsistent, suggests expectations that overall, the technology will enhance the user experience.   This can lead to future examinations of user behavior, response and observation of technologies like AR.

Conversion of alkyl radicals to allyl radicals in irradiated single crystal mats of polyethylene

International Nuclear Information System (INIS)

Fujimura, T.; Hayakawa, N.; Kuriyama, I.

1978-01-01

The decay of alkyl radicals, the conversion of alkyl radicals to allyl radicals and the trapping of allyl radicals in irradiated single crystal mats of polyethylene have been studied by electron spin resonance (e.s.r.). It has been suggested that in the crystal core alkyl radicals react with trans-vinylene double bonds and are converted into trans-vinylene allyl radicals; at the crystal surface, alkyl radicals react with vinyl end groups and are converted into allyl radicals with vinyl end groups. The decay of radical pairs and the formation of trans-vinylene double bonds are discussed. (author)

Hyperfine interactions of a muoniated ethyl radical in supercritical CO2

International Nuclear Information System (INIS)

Cormier, Philip; Taylor, Becky; Ghandi, Khashayar

2009-01-01

A muoniated ethyl radical was studied in supercritical carbon dioxide. The muon and the proton hyperfine coupling constants were measured over temperatures ranging from 305 to 475 K, and a density range from 0.2 to 0.7 (g cm -3 ). A decrease was found in the muon hyperfine coupling constants as a function of the density, which can be attributed to the interaction between the CO 2 molecule and the p-orbital of the ethyl radical. The changes to the α-proton and β-proton hyperfine coupling constants with density are attributed to changes in the overall geometry in the formed radical. This system was modeled using quantum calculations.

Shifting Sands in the United Arab Emirates: Effecting Conceptual Change for Creativity in Early Childhood Teacher Education

Science.gov (United States)

Baker, Fiona S.

2013-01-01

This study examines the effectiveness of a four-stage conceptual change approach to creativity development in teacher education in the Emirate of Dubai, the United Arab Emirates. The participants were 32 student teachers studying at undergraduate level at an all-female university. The study examined participant preconceptions of creativity and how…

Relational iterations and emotional activations: towards a radicalization of processuality of collective identities

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María Martínez

2018-03-01

Full Text Available Collective identity has been conceptualized by social movement theories mainly as a definition. In this text, based in feminist theories, I argue that the conceptualization of collective identity as a definition forgets other fundamental dimensions —mainly relations and emotions— and, moreover, limits its processual character. This argument is based on the study of contemporary feminist mobilizations in Spain through a qualitative fieldwork (quasi-biographical interviews, focus groups, participant observations and the analysis of written and graphic materials. The analysis allows the widening of dimensions of collective identities —from definitions to relations and emotions— as well as the radicalization of their processuality by placing the notions of iteration and activation at the heart of the analysis. I offer a theoretical-analytical proposal that understands that collective identities are but partial materializations, always unfinished processes.

Guest Editorial: Processes of Radicalization and De-Radicalization

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Donatella Della Porta

2012-05-01

Full Text Available The study of radicalization and de-radicalization, understood as processes leading towards the increased or decreased use of political violence, is central to the question of how political violence emerges, how it can be prevented, and how it can be contained. The focus section of this issue of the International Journal of Conflict and Violence addresses radicalization and de-radicalization, seeking to develop a more comprehensive understanding of the processes, dynamics, and mechanisms involved and taking an interdisciplinary approach to overcome the fragmentation into separate disciplines and focus areas. Contributions by Pénélope Larzillière, Felix Heiduk, Bill Kissane, Hank Johnston, Christian Davenport and Cyanne Loyle, Veronique Dudouet, and Lasse Lindekilde address repressive settings, legitimacy, institutional aspects, organizational outcomes, and dynamics in Europe, Asia, Africa, and North and South America.

The "halo effect" in Korea: change in practice patterns since the introduction of robot-assisted laparoscopic radical prostatectomy.

Science.gov (United States)

Sung, Ee-Rah; Jeong, Wooju; Park, Sung Yul; Ham, Won Sik; Choi, Young Deuk; Hong, Sung Joon; Rha, Koon Ho

2009-03-01

Acquisition of the da Vinci surgical system (Intuitive Surgical, Mountain View, USA) has enabled robot-assisted surgery to become an acceptable alternative to open radical prostatectomy (ORP). Implementation of robotics at a single institution in Korea induced a gradual increase in the number of performances of robot-assisted laparoscopic radical prostatectomy (RALP) to surgically treat localized prostate cancer. We analyzed the impact of robotic instrumentation on practice patterns among urologists and explain the change in value in ORP and RALP-the standard treatment and the new approach or innovation of robotic technology. The overall number of prostatectomies has increased over time because the number of RALPs has grown drastically whereas the number of OPRs did not decrease during the period of evaluation. Our experience emphasizes the potential of RALP to become the gold standard in the treatment of localized prostate cancer in various parts of the world.

Metal-catalyzed living radical polymerization and radical polyaddition for precision polymer synthesis

Energy Technology Data Exchange (ETDEWEB)

Mizutani, M; Satoh, K [Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kamigaito, M, E-mail: kamigait@apchem.nagoya-u.ac.j

2009-08-01

The metal-catalyzed radical addition reaction can be evolved into two different polymerization mechanisms, i.e.; chain- and step-growth polymerizations, while both the polymerizations are based on the same metal-catalyzed radical formation reaction. The former is a widely employed metal-catalyzed living radical polymerization or atom transfer radical polymerization of common vinyl monomers, and the latter is a novel metal-catalyzed radical polyaddition of designed monomer with an unconjugated C=C double bond and a reactive C-Cl bond in one molecule. The simultaneous ruthenium-catalyzed living radical polymerization of methyl acrylate and radical polyaddition of 3-butenyl 2-chloropropionate was achieved with Ru(Cp*)Cl(PPh{sub 3}){sub 2} to afford the controlled polymers, in which the homopolymer segments with the controlled chain length were connected by the ester linkage.

The Effect of Conceptual Change Model in the Senior High School Students’ Understanding and Character in Learning Physics

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Santyasa I Wayan

2018-01-01

Full Text Available Learning physics for senior high school (SMA students is often coloured by misconceptions that hinder students in achieving deep understanding. So a relevant learning model is needed. This study aims to examine the effect of conceptual change model (CCM compared with direct instruction model (DIM on the students’ conceptual understanding and character in the subject area of motion and force. This quasi-experimental research using a non-equivalence pre-test post-test control groups design. The population is 20 classes (738 students of grade X consisted of 8 classes (272 students of SMA 1 Amlapura, 8 classes (256 students of SMA 2 Amlapura, and 6 classes (210 students of SMA 1 Manggis in Karangasem regency in Bali. The random assignment technique is used to assign 6 classes (202 students, or 26.5% of the population. In each school there are set 2 classes each as a CCM group and DIM groups. The data of students’ conceptual understanding is collected by tests, while the characters by questionnaires. To analyse the data a one way MANCOVA statistics was used. The result of the analysis showed that there was a significant difference of effect between CCM group and DIM group on the students’ conceptual understanding and character. The effect of the CCM group is higher than the DIM group on the students’ conceptual understanding and character in learning subject area of motion and force.

Radical and Not So Radical Transgressions: Invading Backstage Domains

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Lada Čale Feldman

2012-06-01

Full Text Available Featuring as one of the privileged metaphors in humanities and social sciences, theatre provides primarily an image of a circumscribed space whose spatial syntax and modes of human engagement take place within and with respect to the larger space of the city, the world, and, as in Calderon’s Gran teatro del mundo, the universe. It is precisely as a special organization of spatiality that theatre reached the status of Foucault’s radical hetero-topos, flexible as it proved to be as a model for not only counter-representing all the human dealings in the external space, but also of conceptualizing, as in Freud’s psychoanalysis, man’s inner world, his psychic topography. But theatre is above all a concrete place, a built form with its own spatial history, its changing social and ideological functions, and its ways of bestowing to the bodies that enter into it actual or phantasm identities, thoughts, sensations, feelings and memories.My intervention will deal with one of the ruling borders/dichotomies/barriers of theatrical space, the one dividing “front stage” from “backstage” regions. In his detailed analysis of the latter in an individual and concrete theatre building, Andrew Filmer relies among others on Edward Soja’s “trialectics of being”, and thus also on Lefebvre’s categories of perceptual, conceptual and lived aspects of spatiality which Soja evokes, which will here be of particular interest. In contrast to the repercussions of such an analytical triad for the ethnographic study of concrete theatrical sites, I will ask how it pertains to potential manipulations of the aforementioned division of front-stage and backstage within contemporary performance practice. The temporal aspect of this manipulation should also be emphasized, having in mind the historical provenance of a whole backstage mythology – evidenced in numerous novels, plays and films situated in the backstage world - in the elaborated architectural

Determinants of Enterprises Radical Innovation and Performance: Insights into Strategic Orientation of Cultural and Creative Enterprises

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Tsui-Yii Shih

2018-06-01

Full Text Available A firm’s strategic orientation determine its business direction and scope of operation. Several researchers have tried to identify how strategic orientations affect business development. However, only a few scholars have explored how strategic orientations shape a firm’s organizational capability. In addition, the extent to which radical innovation contributes to a firm’s operations has not been well researched. Given these research shortcomings, this study explores the integration of firms’ strategic orientations, radical innovation, competitive advantages, and business performance within a conceptual framework. A sample of 86 cultural and creative firms was obtained. The results of the regression analysis and of the PLS SEM model are compared in this study. Our findings suggest that factors from either market orientation or entrepreneurial orientation add to a firm’s radical innovation capability and adoption. Lastly, the brand advantage is identified to be the most important factor in firms’ performance after a radical innovation capability and product advantage. This paper offers several contributions to the research. First, it advances knowledge of the strategic orientations of cultural and creative firms in a developing market. Second, it demonstrates the usefulness of radical innovation capability in profiling the development of competitive advantages. Lastly, it adds to our understanding of factors that facilitate the business performance of cultural and creative entrepreneurs.

Conceptualizing operations strategy processes

DEFF Research Database (Denmark)

Rytter, Niels Gorm; Boer, Harry; Koch, Christian

2007-01-01

Purpose - The purpose of this paper is to present insights into operations strategy (OS) in practice. It outlines a conceptualization and model of OS processes and, based on findings from an in-depth and longitudinal case study, contributes to further development of extant OS models and methods......; taking place in five dimensions of change - technical-rational, cultural, political, project management, and facilitation; and typically unfolding as a sequential and parallel, ordered and disordered, planned and emergent as well as top-down and bottom-up process. The proposed OS conceptualization...

Search for flavour changing neutral currents in single top-quark production at {radical}(s)=7 TeV with the ATLAS detector

Energy Technology Data Exchange (ETDEWEB)

Alhroob, Muhammad

2013-03-15

This thesis represents the search for single top-quark production through flavour changing neutral currents using data collected by the ATLAS detector in 2011, at a centre-of-mass energy of {radical}(s)=7 TeV, corresponding to an integrated luminosity of 2.05 fb{sup -1}. Candidate events are selected with one isolated lepton, missing transverse momentum associated to the undetected neutrino and a jet originated from the hadronisation of a b quark. Given the large expected number of background events and the small number of expected signal events, a neural network classifier is developed to combine many kinematic variables to create a powerful separator in order classify the events as a signal- or a background-like events. As no sign of new physics is seen in the neural network output distribution, a Bayesian statistical method is used to set an upper limit at 95% confidence level (C.L.) on the single top-quark production cross section through FCNC processes. The observed upper limit at 95% C.L. on the cross-section multiplied by the t{yields}Wb branching fraction is measured to be {sigma}{sub qg{yields}t} x B(t {yields}Wb)< 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths (K{sub ugt})/({Lambda})<6.9.10{sup -3} TeV{sup -1} and (K{sub cgt})/({Lambda})<1.6.10{sup -2} TeV{sup -1}, where {Lambda} is the new physics scale, and on the branching fractions B(t{yields}ug)<5.7 .10{sup -5} and B(t{yields}cg)< 2.7.10{sup -4}. The limits on the branching fractions are the world's best limits to date and significantly improving the previous limits obtained by the DOe collaboration by a factor of 15.

The conceptualization model problem—surprise

Science.gov (United States)

Bredehoeft, John

2005-03-01

The foundation of model analysis is the conceptual model. Surprise is defined as new data that renders the prevailing conceptual model invalid; as defined here it represents a paradigm shift. Limited empirical data indicate that surprises occur in 20-30% of model analyses. These data suggest that groundwater analysts have difficulty selecting the appropriate conceptual model. There is no ready remedy to the conceptual model problem other than (1) to collect as much data as is feasible, using all applicable methods—a complementary data collection methodology can lead to new information that changes the prevailing conceptual model, and (2) for the analyst to remain open to the fact that the conceptual model can change dramatically as more information is collected. In the final analysis, the hydrogeologist makes a subjective decision on the appropriate conceptual model. The conceptualization problem does not render models unusable. The problem introduces an uncertainty that often is not widely recognized. Conceptual model uncertainty is exacerbated in making long-term predictions of system performance. C'est le modèle conceptuel qui se trouve à base d'une analyse sur un modèle. On considère comme une surprise lorsque le modèle est invalidé par des données nouvelles; dans les termes définis ici la surprise est équivalente à un change de paradigme. Des données empiriques limitées indiquent que les surprises apparaissent dans 20 à 30% des analyses effectuées sur les modèles. Ces données suggèrent que l'analyse des eaux souterraines présente des difficultés lorsqu'il s'agit de choisir le modèle conceptuel approprié. Il n'existe pas un autre remède au problème du modèle conceptuel que: (1) rassembler autant des données que possible en utilisant toutes les méthodes applicables—la méthode des données complémentaires peut conduire aux nouvelles informations qui vont changer le modèle conceptuel, et (2) l'analyste doit rester ouvert au fait

Free radicals created by radiation and aging symptoms

International Nuclear Information System (INIS)

Ashry, O.M.

2012-01-01

The universality of aging implies that its cause is basically the same in all species. A free radical hypothesis of aging has been proposed that the free radicals produced during normal metabolism of the cell over time damage DNA and other macromolecules leading to degenerative diseases, malignancies, and eventual death of vital cells which in turn causes aging and death of the organism. This hypothesis is supported by several observations. Radiation produces its biologic effect through free radical formation and causes premature aging. Second, the age pigment lipo fuscin is associated with lipid peroxidation. The hypothesis that oxygen radicals play a role in aging is also supported by the observation that, in general, long-lived species produce less endogenous free oxygen radicals because of their lower metabolic rate. Long-lived animals also have more superoxide dismutase than do their short-lived counterparts, and animal species with the longest lifespan have the highest levels of superoxide dismutase. Oxidative DNA damage is rapidly and effectively repaired. It has been estimated that there are several thousand oxidative DNA damage sites in a human cell every day, and the majority of these are repaired. However, a small fraction of unrepaired lesions could cause permanent changes in DNA and might be a major contributor to aging and cancer. A consequence of the free radical hypothesis of aging is the idea that free radical scavenging agents might be used to prevent aging. (author)

Climate change-contaminant interactions in marine food webs: Toward a conceptual framework.

Science.gov (United States)

Alava, Juan José; Cheung, William W L; Ross, Peter S; Sumaila, U Rashid

2017-10-01

Climate change is reshaping the way in which contaminants move through the global environment, in large part by changing the chemistry of the oceans and affecting the physiology, health, and feeding ecology of marine biota. Climate change-associated impacts on structure and function of marine food webs, with consequent changes in contaminant transport, fate, and effects, are likely to have significant repercussions to those human populations that rely on fisheries resources for food, recreation, or culture. Published studies on climate change-contaminant interactions with a focus on food web bioaccumulation were systematically reviewed to explore how climate change and ocean acidification may impact contaminant levels in marine food webs. We propose here a conceptual framework to illustrate the impacts of climate change on contaminant accumulation in marine food webs, as well as the downstream consequences for ecosystem goods and services. The potential impacts on social and economic security for coastal communities that depend on fisheries for food are discussed. Climate change-contaminant interactions may alter the bioaccumulation of two priority contaminant classes: the fat-soluble persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), as well as the protein-binding methylmercury (MeHg). These interactions include phenomena deemed to be either climate change dominant (i.e., climate change leads to an increase in contaminant exposure) or contaminant dominant (i.e., contamination leads to an increase in climate change susceptibility). We illustrate the pathways of climate change-contaminant interactions using case studies in the Northeastern Pacific Ocean. The important role of ecological and food web modeling to inform decision-making in managing ecological and human health risks of chemical pollutants contamination under climate change is also highlighted. Finally, we identify the need to develop integrated policies that manage the

Investigating and Promoting Trainee Science Teachers' Conceptual Change of the Nature of Science with Digital Dialogue Games `InterLoc'

Science.gov (United States)

Mansour, Nasser; Wegerif, Rupert; Skinner, Nigel; Postlethwaite, Keith; Hetherington, Lindsay

2016-10-01

The purpose of this study is to explore how an online-structured dialogue environment supported (OSDE) collaborative learning about the nature of science among a group of trainee science teachers in the UK. The software used (InterLoc) is a linear text-based tool, designed to support structured argumentation with openers and `dialogue moves'. A design-based research approach was used to investigate multiple sessions using InterLoc with 65 trainee science teachers. Five participants who showed differential conceptual change in terms of their Nature of Science (NOS) views were purposively selected and closely followed throughout the study by using key event recall interviews. Initially, the majority of participants held naïve views of NOS. Substantial and favourable changes in these views were evident as a result of the OSDE. An examination of the development of the five participants' NOS views indicated that the effectiveness of the InterLoc discussions was mediated by cultural, cognitive, and experiential factors. The findings suggest that InterLoc can be effective in promoting reflection and conceptual change.

Student beliefs and learning environments: Developing a survey of factors related to conceptual change

Science.gov (United States)

Hanrahan, Mary

1994-12-01

This paper presents a model for the type of classroom environment believed to facilitate scientific conceptual change. A survey based on this model contains items about students' motivational beliefs, their study approach and their perceptions of their teacher's actions and learning goal orientation. Results obtained from factor analyses, correlations and analyses of variance, based on responses from 113 students, suggest that an empowering interpersonal teacher-student relationship is related to a deep approach to learning, a positive attitude to science, and positive self-efficacy beliefs, and may be increased by a constructivist approach to teaching.

DPPH and oxygen free radicals as pro-oxidant of biomolecules.

Science.gov (United States)

Letelier, María Eugenia; Molina-Berríos, Alfredo; Cortés-Troncoso, Juan; Jara-Sandoval, José; Holst, Marianne; Palma, Karina; Montoya, Margarita; Miranda, Dante; González-Lira, Víctor

2008-03-01

Numerous investigations exist about the alterations that oxygen free radicals can provoke on biomolecules; these modifications can be prevented and/or reversed by different antioxidants agents. On the other hand, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), a stable nitrogen synthetic radical, is used to evaluate the antioxidant capacity of medicinal herbal products; however, the structural changes that this radical provoke on the herbal active principles are not clear yet. In this work, we compared the redox reactivity of oxygen free radicals and DPPH radical on phospholipids and protein thiol groups present in rat liver microsomes. Cu2+/ascorbate was used as generator system of oxygen free radical and as antioxidant, an extract of Buddleja globosa's leaves. Cu2+/ascorbate provoked microsomal lipid peroxidation, microsomal thiols oxidation and oxygen consumption; all of these phenomena were inhibited by B. globosa extract. On the other hand, DPPH was bleached in different extension by the herbal extract and phosphatidyl choline; beside, DPPH decreased microsomal thiols content, but this phenomenon were not prevented by the herbal extract. Furthermore, DPPH did not induce oxygen consumption and neither modified the oxygen consumption induced by Cu2+/ascorbate. Distinct redox mechanisms may explain the differences between the reactivity of DPPH and oxygen free radicals on biomolecules, which is discussed.

The games radicals play : special issue on free radicals and radical ions

OpenAIRE

Walton, J.C.; Williams, F.

2015-01-01

Chemistry and Physics have aptly been described as “most excellent children of Intellect and Art” [1]. Both these “children” engage with many playthings, and molecules rank as one of their first favorites, especially radicals, which are amongst the most lively and exciting. Checking out radicals dancing to the music of entropy round their potential energy ballrooms is surely both entertaining and enlightening. Radicals’ old favorite convolutions are noteworthy, but the new styles, modes and a...

Investigating free radical generation in HepG2 cells using immuno-spin trapping.

Science.gov (United States)

Horinouchi, Yuya; Summers, Fiona A; Ehrenshaft, Marilyn; Kawazoe, Kazuyoshi; Tsuchiya, Koichiro; Tamaki, Toshiaki; Mason, Ronald P

2014-10-01

Oxidative stress can induce the generation of free radicals, which are believed to play an important role in both physiological and pathological processes and a number of diseases such as cancer. Therefore, it is important to identify chemicals which are capable of inducing oxidative stress. In this study, we evaluated the ability of four environmental chemicals, aniline, nitrosobenzene (NB), N,N-dimethylaniline (DMA) and N,N-dimethyl-4-nitrosoaniline (DMNA), to induce free radicals and cellular damage in the hepatoma cell line HepG2. Cytotoxicity was assessed using lactate dehydrogenase (LDH) assays and morphological changes were observed using phase contrast microscopy. Free radicals were detected by immuno-spin trapping (IST) in in-cell western experiments or in confocal microscopy experiments to determine the subcellular localization of free radical generation. DMNA induced free radical generation, LDH release and morphological changes in HepG2 cells whereas aniline, NB and DMA did not. Confocal microscopy showed that DMNA induced free radical generation mainly in the cytosol. Preincubation of HepG2 cells with N-acetylcysteine and 2,2'-dipyridyl significantly prevented free radical generation upon subsequent incubation with DMNA, whereas preincubation with apocynin and dimethyl sulfoxide did not. These results suggest that DMNA induces oxidative stress and that reactive oxygen species, metals and free radical generation play a critical role in DMNA-induced cytotoxicity. Copyright © 2014. Published by Elsevier Inc.

Time resolved resonance Raman spectra of anilino radical and aniline radical cation

International Nuclear Information System (INIS)

Tripathi, G.N.R.; Schuler, R.H.

1987-01-01

We report, in this paper, submicrosecond time resolved resonance Raman spectra of anilino radical and its radical cation as observed in pulse radiolytic studies of the oxidation of aniline in aqueous solution. By excitation in resonance with the broad and weak electronic transition of anilino radical at 400 nm (ε--1250 M -1 cm -1 ) we have observed, for the first time, the vibrational features of this radical. The Wilson ν 8 /sub a/ ring stretching mode at 1560 cm -1 is most strongly resonance enhanced. The ν 7 /sub a/ CN stretching band at 1505 cm -1 , which is shifted to higher frequency by 231 cm -1 with respect to aniline, is also prominent. The frequency of this latter mode indicates that the CN bond in the radical has considerable double bond character. The Raman spectrum of aniline radical cation, excited in resonance with the --425 nm electronic absorption (ε--4000 M -1 cm -1 ), shows features which are similar to phenoxyl radical. Most of the observed frequencies of this radical in solution are in good agreement with vibrational energies determined by recent laser photoelectron spectroscopic studies in the vapor phase. The bands most strongly enhanced in the resonance Raman spectrum are, however, weak in the photoelectron spectrum. While the vibrational frequencies observed for anilino radical and its isoelectronic cation are quite similar, the resonance enhancement patterns are very different. In particular the ν 14 b 2 mode of anilino radical observed at 1324 cm -1 is highly resonance enhanced because of strong vibronic coupling between the 400 nm 2 A 2 -- 2 B 1 and the higher 2 B 1 -- 2 B 1 electronic transitions

Validation of an Instrument for Assessing Conceptual Change with Respect to the Theory of Evolution by Secondary Biology Students

Science.gov (United States)

Goff, Kevin David

This pilot study evaluated the validity of a new quantitative, closed-response instrument for assessing student conceptual change regarding the theory of evolution. The instrument has two distinguishing design features. First, it is designed not only to gauge student mastery of the scientific model of evolution, but also to elicit a trio of deeply intuitive tendencies that are known to compromise many students' understanding: the projection of intentional agency, teleological directionality, and immutable essences onto biological phenomena. Second, in addition to a section of conventional multiple choice questions, the instrument contains a series of items where students may simultaneously endorse both scientifically normative propositions and intuitively appealing yet unscientific propositions, without having to choose between them. These features allow for the hypothesized possibility that the three intuitions are partly innate, themselves products of cognitive evolution in our hominin ancestors, and thus may continue to inform students' thinking even after instruction and conceptual change. The test was piloted with 340 high school students from diverse schools and communities. Confirmatory factor analysis and other statistical methods provided evidence that the instrument already has strong potential for validly distinguishing students who hold a correct scientific understanding from those who do not, but that revision and retesting are needed to render it valid for gauging students' adherence to intuitive misconceptions. Ultimately the instrument holds promise as a tool for classroom intervention studies by conceptual change researchers, for diagnostic testing and data gathering by instructional leaders, and for provoking classroom dialogue and debate by science teachers.

Free radicals, oxygen and radiosensitizing drugs: a very brief introduction

International Nuclear Information System (INIS)

Willson, R.

1981-01-01

A review is presented of the historical aspects of the search for radiation sensitizing drugs. Metronidazole, Flagyl and misonidazole are undergoing clincial trials as the result of basic free radical and cellular research. Studies at the molecular, biochemical and cellular levels are described. From the information obtained it now appears that several processes may be involved in sensitization: interference with charge recombination due to a sensitizer having a high electron affinity; an increase in the yield of oxidizing hydroxyl radicals by electron sequestration; interference with radical combination reactions due to a sensitizer having a high one electron oxidation potential; oxidation or organic radicals so fixing them; formation of products which are toxic; and changes in the biochemistry of the cell. 106 references, 4 figures

Intramolecular transformation of thiyl radicals to α-aminoalkyl radicals: 'ab initio' calculations on homocystein

International Nuclear Information System (INIS)

Chhun, S.; Berges, J.; Bleton, V.; Abedinzadeh, Z.

2000-01-01

One-electron oxidation of thiols by oxidizing radicals leads to the formation of thiyl radical and carbon-centered radicals. It has been shown experimentally that in the absence of oxygen, the thiyl radicals derived from certain thiols of biological interest such as glutathion, cysteine and homocysteine decay rapidly by intramolecular rearrangement reactions into the carbon-centered radical. In the present work we have investigated theoretically the structure and the stability of thiyl and carbon-centered radicals of homocysteine in order to check the possibility of this rearrangement. (author)

Free radical transfer in polymers

International Nuclear Information System (INIS)

Sonntag, C. von; Bothe, E.; Ulanski, P.

1998-01-01

For the present study of free-radical transfer in polymers pulse radiolysis and product studies have been carried out in aqueous solutions using thus far only the water-soluble polymers polyacrylic acid, polymethacrylic acid and polyvinyl alcohol. When OH radicals, generated in the radiolysis of N 2 O-saturated aqueous solutions, react with polymers the lifetime of the polymer radical thus created very much depends on the number of radicals per polymer chain. When there are a large number of radicals per chain their bimolecular decay may be faster than the corresponding (diffusion controlled) decay of monomeric radicals, but when the macromolecule contains only few or even just one radical their lifetime is considerably prolonged. Highly charged polymers such as polyacrylic acid at high pH attain a rod-like conformation which again favors a long lifetime of the radicals. Under such conditions, radical transfer reactions can occur. For example, in polyacrylic acid OH radicals generate two kinds of radicals side by side. The radical in β-position to the carboxylate group converts into the thermodynamically more stable α-radicals by an H-transfer reaction as can be followed by spectrophotometry. Besides radical transfer reactions β-fragmentation reactions occur causing chain scission. Such reactions can be followed in a pulse radiolysis experiment by conductometry, because counter ions are released upon chain scission. Such a process is especially effective in the case of polymethacrylic acid, where it results in a chain depolymerization. An intramolecular H-abstraction is also observed in the γ-radiolysis of polyacrylic acid with the corresponding peroxyl radicals. This causes a chain reaction to occur. The resulting hydroperoxides are unstable and decarboxylate given rise to acetylacetone-like products. In polyvinyl alcohol the peroxyl radicals in α-position to the alcohol function undergo HO 2 -elimination. This prevents a scission of the polymer chain in the

Radical Left in Albania and Kosovo: Differences and Similarities

Directory of Open Access Journals (Sweden)

Këlliçi Klejd

2017-06-01

Full Text Available The main research question for this paper is: Are there radical left wing movements in Albania and Kosovo and what are their main traits? Through answering this question, we will explore the development (or lack thereof of radical left wing movements. With radical left we intend movements that reject the underlying socio-economic structure of contemporary capitalism and its values and practices without opposing democracy. Through a thorough desk research and several interviews with experts and activists both in Albania and Kosovo, we look at the two case Political Opportunity Structures to study the emergence, the strategies, success or failures of the radical left. In Albania the radical left has been in decline since 1992, with only a recent revival from 2009 on. In Kosovo, the Lëvizja Vetëvendojse! (Self-Determination Movement, a civil movement transformed in a party, has succeeded in imposing its left agenda. Both cases employ a new rhetoric unrelated to the past communist regimes thus changing the perspective of political debate in both countries.

Delocalization model of regioselectivity and reactivity of free radicals in reactions of addition to olefins

International Nuclear Information System (INIS)

Volovik, S.V.; Dyadyusha, G.G.; Staninets, V.I.

1987-01-01

On the basis of the concept of polarity (philicity) of free radicals as proposed by the authors, within the framework of methods of qualitative surfaces of potential energy (linear combinations of configurations of fragments) and stabilization energy, an effective model has been developed for the regioselectivity and reactivity of radicals in processes of addition. A critical examination is made of certain key aspects of the change in regiochemistry and reactivity with changes in the electronic structure of the free radical and substrate. The dominant trends in regioselectivity and reactivity in processes of free-radical addition to olefins are controlled by electronic effects and can be predicted by analyzing interactions of diabatic potential energy surfaces or orbital interactions for a system consisting of a free radical and an unsaturated substrate

Free radical reaction characteristics of coal low-temperature oxidation and its inhibition method.

Science.gov (United States)

Li, Zenghua; Kong, Biao; Wei, Aizhu; Yang, Yongliang; Zhou, Yinbo; Zhang, Lanzhun

2016-12-01

Study on the mechanism of coal spontaneous combustion is significant for controlling fire disasters due to coal spontaneous combustion. The free radical reactions can explain the chemical process of coal at low-temperature oxidation. Electron spin resonance (ESR) spectroscopy was used to measure the change rules of the different sorts and different granularity of coal directly; ESR spectroscopy chart of free radicals following the changes of temperatures was compared by the coal samples applying air and blowing nitrogen, original coal samples, dry coal samples, and demineralized coal samples. The fragmentation process was the key factor of producing and initiating free radical reactions. Oxygen, moisture, and mineral accelerated the free radical reactions. Combination of the free radical reaction mechanism, the mechanical fragmentation leaded to the elevated CO concentration, fracturing of coal pillar was more prone to spontaneous combustion, and spontaneous combustion in goaf accounted for a large proportion of the fire in the mine were explained. The method of added diphenylamine can inhibit the self-oxidation of coal effectively, the action mechanism of diphenylamine was analyzed by free radical chain reaction, and this research can offer new method for the development of new flame retardant.

The Contribution of Conceptual Change Texts Accompanied by Concept Mapping to Eleventh-Grade Students Understanding of Cellular Respiration Concepts

Science.gov (United States)

Al khawaldeh, Salem A.; Al Olaimat, Ali M.

2010-01-01

The present study conducted to investigate the contribution of conceptual change texts, accompanied by concept mapping instruction to eleventh-grade students' understanding of cellular respiration concepts, and their retention of this understanding. Cellular respiration concepts test was developed as a result of examination of related literature…

Hyperfine interactions of a muoniated ethyl radical in supercritical CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Cormier, Philip; Taylor, Becky [Department of Chemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8 (Canada); Ghandi, Khashayar, E-mail: kghandi@mta.c [Department of Chemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8 (Canada)

2009-04-15

A muoniated ethyl radical was studied in supercritical carbon dioxide. The muon and the proton hyperfine coupling constants were measured over temperatures ranging from 305 to 475 K, and a density range from 0.2 to 0.7 (g cm{sup -3}). A decrease was found in the muon hyperfine coupling constants as a function of the density, which can be attributed to the interaction between the CO{sub 2} molecule and the p-orbital of the ethyl radical. The changes to the alpha-proton and beta-proton hyperfine coupling constants with density are attributed to changes in the overall geometry in the formed radical. This system was modeled using quantum calculations.

beta-Scission of C-3 (beta-carbon) alkoxyl radicals on peptides and proteins

DEFF Research Database (Denmark)

Headlam, H A; Mortimer, A; Easton, C J

2000-01-01

Exposure of proteins to radicals in the presence of O(2) brings about multiple changes in the target molecules. These alterations include oxidation of side chains, fragmentation, cross-linking, changes in hydrophobicity and conformation, altered susceptibility to proteolytic enzymes, and formation...... of methanal (formaldehyde). This product has been quantified with a number of oxidized peptides and proteins, and can account for up to 64% of the initial attacking radicals with some Ala peptides. When quantified together with the hydroperoxide precursors, these species account for up to 80% of the initial...... radicals, confirming that this is a major process. Methanal causes cell toxicity and DNA damage and is an animal carcinogen and a genotoxic agent in human cells. Thus, the formation and subsequent reaction of alkoxyl radicals formed at the C-3 position on aliphatic amino acid side chains on peptides...

Development of a new free radical absorption capacity assay method for antioxidants: aroxyl radical absorption capacity (ARAC).

Science.gov (United States)

Nagaoka, Shin-ichi; Nagai, Kanae; Fujii, Yuko; Ouchi, Aya; Mukai, Kazuo

2013-10-23

A new free radical absorption capacity assay method is proposed with use of an aroxyl radical (2,6-di-tert-butyl-4-(4'-methoxyphenyl)phenoxyl radical) and stopped-flow spectroscopy and is named the aroxyl radical absorption capacity (ARAC) assay method. The free radical absorption capacity (ARAC value) of each tocopherol was determined through measurement of the radical-scavenging rate constant in ethanol. The ARAC value could also be evaluated through measurement of the half-life of the aroxyl radical during the scavenging reaction. For the estimation of the free radical absorption capacity, the aroxyl radical was more suitable than the DPPH radical, galvinoxyl, and p-nitrophenyl nitronyl nitroxide. The ARAC value in tocopherols showed the same tendency as the free radical absorption capacities reported previously, and the tendency was independent of an oxygen radical participating in the scavenging reaction and of a medium surrounding the tocopherol and oxygen radical. The ARAC value can be directly connected to the free radical-scavenging rate constant, and the ARAC method has the advantage of treating a stable and isolable radical (aroxyl radical) in a user-friendly organic solvent (ethanol). The ARAC method was also successfully applied to a palm oil extract. Accordingly, the ARAC method would be useful in free radical absorption capacity assay of antioxidative reagents and foods.

The implications of how climate funds conceptualize transformational change in developing countries

DEFF Research Database (Denmark)

Boodoo, Zyaad; Mersmann, Florian; Olsen, Karen Holm

2018-01-01

Mitigation Actions (NAMAs) is emerging as a crucial feature to attain this goal. Against this background, two of the major NAMA funding agencies have embraced ‘transformational change (TC)’ and ‘paradigm shifts’ as policy concepts. Yet, their operationalization within aid management approaches has not been...... fully justified. Concurrently, academic interest in theories of sustainability transitions has been growing, out of which the Transition Management (TM) approach provides the theoretical inspiration to study, and eventually promote, systemic TCs. However, there is still limited knowledge with which...... to contextualize the steering of such transitions to different settings. This article engages in these debates by reviewing the theoretical grounding behind the Green Climate Fund and the NAMA Facility’s conceptualizations of TC through NAMA interventions against the corresponding theoretical assumptions of TM...

Measurement of radical scavenging activity of irradiated Kampo extracts using ESR spin-trap method

International Nuclear Information System (INIS)

Ohta, Yui; Kawamura, Shoei; Ukai, Mitsuko; Nakamura, Hideo; Kikuchi, Masahiro; Kobayashi, Yasuhiko

2014-01-01

The radical scavenging activity (RSA) of 13 kinds of γ-ray irradiated Kampo extracts were studied by ESR spin-trap method. The RSA against alkoxy radical and hydroxyl radical were measured using new spin trapping reagent CYPMPO. The RSA against these two radicals were evaluated using GSH for alkoxy RSA and L-ascorbic acid for hydroxy RSA as a standard antioxidant reagent. We revealed that a few Kampo extracts showed high RSA against alkoxy radical and also hydroxy radical. This RSA of Kampo extracts was changed by γ-ray irradiation treatment. Using ESR spin-trap method, it is concluded that the effect of radiation treatment on RSA of Kampo extracts were able to detect. (author)

The Impact of Cognitive and Affective Aspects of Cognitive Conflict on Learners' Conceptual Change about Floating and Sinking

Science.gov (United States)

Hadjiachilleos, Stella; Valanides, Nicos; Angeli, Charoula

2013-01-01

Background: Cognitive conflict has been identified as an important factor for bringing about students' conceptual change. Researchers draw attention to the need to study not only cognitive factors related to cognitive conflict but affective factors as well. Purpose: The purpose of this study was to investigate the contribution of cognitive…

Vinylcyclopropylacyl and polyeneacyl radicals. Intramolecular ketene alkyl radical additions in ring synthesis.

Science.gov (United States)

De Boeck, Benoit; Herbert, Nicola M A; Harrington-Frost, Nicole M; Pattenden, Gerald

2005-01-21

Treatment of a variety of substituted vinylcyclopropyl selenyl esters, e.g. 11, with Bu(3)SnH-AIBN in refluxing benzene leads to the corresponding acyl radical intermediates, which undergo rearrangement and intramolecular cyclisations via their ketene alkyl radical equivalents producing cyclohexenones in 50-60% yield. By contrast, treatment of conjugated triene selenyl esters, e.g. 32, with Bu(3)SnH-AIBN produces substituted 2-cyclopentenones via intramolecular cyclisations of their ketene alkyl radical intermediates. Under the same radical-initiating conditions the selenyl esters derived from o-vinylbenzoic acid and o-vinylcinnamic acid undergo intramolecular cyclisations producing 1-indanone and 5,6-dihydrobenzocyclohepten-7-one respectively in 60-70% yields. A tandem radical cyclisation from the alpha,beta,gamma,delta-diene selenyl ester 31 provides an expeditious synthesis of the diquinane 35 in 69% yield.

Structure and Intramolecular Proton Transfer of Alanine Radical Cations

International Nuclear Information System (INIS)

Lee, Gab Yong

2012-01-01

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the NH 2 group upon ionization. Ionization favors the intramolecular proton transfer process, leading to a proton-transferred radical-cation structure, [NH 3 + -CHCH 3 -COO·], which contrasts with the fact that a proton-transferred zwitterionic conformer is not stable for a neutral alanine in the gas phase. The energy barrier during the proton transfer process is calculated to be about 6 kcal/mol

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

Science.gov (United States)

Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

2009-01-01

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

The Effect of Conceptual Change Approach to Eliminate 9th Grade High School Students' Misconceptions about Air Pressure

Science.gov (United States)

Akbas, Yavuz; Gencturk, Ebru

2011-01-01

The aim of this study was to determine the effectiveness of teaching based on conceptual change overcome misconceptions of 9th grade high school students about the subject of air pressure. The sampling of the study was formed with two classes of 9th grade students from a general high school in the city-center of Trabzon. A quasi-experimental…

Radical transfer between proteins: role of tyrosine, tryptophan and protein peroxyl radicals

International Nuclear Information System (INIS)

Irwin, J.A.; Ostdal, H.; Davies, M.J.

1998-01-01

Reaction of the Fe(III) forms of the heme proteins myoglobin (Mb) and horseradish peroxidase (HRP) with H 2 O 2 gives rise to high-oxidation-state heme-derived species which can be described as a Fe(IV)-oxo porphyrin radical-cation ('Compound 1'). In the case of Mb, the Fe(IV)-oxo porphyrin radical-cation undergoes rapid electron transfer with the surrounding protein to give protein (globin)-derived radicals and an Fe(lV)-oxo species ('Compound 2'). The globin-derived radicals have been shown to be located at two (or more) sites: Tyr-103 or Trp-14, with the latter radical known to react with oxygen to give a Trp-derived peroxyl radical (Mb-Trp-OO*). With HRP, the Fe(lV)-oxo porphyrin radical-cation carries out two successive one-electron oxidation reactions at the exposed heme edge to give firstly 'Compound 2' [the Fe(lV)oxo species] and then the resting Fe(III) state of the enzyme. n this study we have investigated whether the Trp-14 peroxyl radical from Mb and the Compound 1 and 2 species from HRP (in the absence and presence of free Tyr) can oxidise amino acids, peptides and proteins. Such reactions constitute intermolecular protein-to-protein radical transfer reactions and hence protein chain-oxidation. We have also examined whether these oxidants react with antioxidants. Reaction of these heme-protein derived oxidants with amino acids, proteins and antioxidants has been carried out at room temperature for defined periods of time before freeze-quenching to 77K to halt reaction. The radical species present in the reaction system at the time of freezing were subsequently examined by EPR spectroscopy at 77K. Three free amino acids, Tyr, Trp and Cys (with Cys the least efficient) have been shown to react rapidly with Mb-Trp-OO*, as evidenced by the loss of the characteristic EPR features of Mb-Trp-OO* on inclusion of increasing concentrations of the amino acids. All other amino acids are much less reactive. Evidence has also been obtained for (inefficient) hydrogen

Free Radical Imaging Using In Vivo Dynamic Nuclear Polarization-MRI.

Science.gov (United States)

Utsumi, Hideo; Hyodo, Fuminori

2015-01-01

Redox reactions that generate free radical intermediates are essential to metabolic processes, and their intermediates can produce reactive oxygen species, which may promote diseases related to oxidative stress. The development of an in vivo electron spin resonance (ESR) spectrometer and its imaging enables us noninvasive and direct measurement of in vivo free radical reactions in living organisms. The dynamic nuclear polarization magnetic resonance imaging (DNP-MRI), also called PEDRI or OMRI, is also a new imaging method for observing free radical species in vivo. The spatiotemporal resolution of free radical imaging with DNP-MRI is comparable with that in MRI, and each of the radical species can be distinguished in the spectroscopic images by changing the frequency or magnetic field of ESR irradiation. Several kinds of stable nitroxyl radicals were used as spin probes to detect in vivo redox reactions. The signal decay of nitroxyl probes, which is determined with in vivo DNP-MRI, reflects the redox status under oxidative stress, and the signal decay is suppressed by prior administration of antioxidants. In addition, DNP-MRI can also visualize various intermediate free radicals from the intrinsic redox molecules. This noninvasive method, in vivo DNP-MRI, could become a useful tool for investigating the mechanism of oxidative injuries in animal disease models and the in vivo effects of antioxidant drugs. © 2015 Elsevier Inc. All rights reserved.

Changes induced in spice paprika powder by treatment with ionizing radiation and saturated steam[Food conservation; Spice paprika; Rheology; Colorimetry; Free radicals

Energy Technology Data Exchange (ETDEWEB)

Kispeter, J. E-mail: kispeter@szef.u-szeged.hu; Bajusz-Kabok, K.; Fekete, M.; Szabo, G.; Fodor, E.; Pali, T. E-mail: tpali@nucleus.szbk.u-szeged.hu

2003-12-01

The changes in spice paprika powder induced by ionizing radiation, saturated steam (SS) and their combination were studied as a function of the absorbed radiation dose and the storage time. The SS treatment lead to a decrease in color content (lightening) after 12 weeks of storage, together with the persistence of free radicals and viscosity changes for a longer period. The results suggest that ionizing radiation is a more advantageous method as concerns preservation of the quality of spice paprika.

Free radical generation from an aniline derivative in HepG2 cells: a possible captodative effect.

Science.gov (United States)

Horinouchi, Yuya; Summers, Fiona A; Ehrenshaft, Marilyn; Mason, Ronald P

2015-01-01

Xenobiotic metabolism can induce the generation of protein radicals, which are believed to play an important role in the toxicity of chemicals and drugs. It is therefore important to identify chemical structures capable of inducing macromolecular free radical formation in living cells. In this study, we evaluated the ability of four structurally related environmental chemicals, aniline, nitrosobenzene, N,N-dimethylaniline, and N,N-dimethyl-4-nitrosoaniline (DMNA), to induce free radicals and cellular damage in the hepatoma cell line HepG2. Cytotoxicity was assessed using lactate dehydrogenase assays, and morphological changes were observed using phase contrast microscopy. Protein free radicals were detected by immuno-spin trapping using in-cell western experiments and confocal microscopy to determine the subcellular locale of free radical generation. DMNA induced free radical generation, lactate dehydrogenase release, and morphological changes in HepG2 cells, whereas aniline, nitrosobenzene, N,N-dimethylaniline did not. Confocal microscopy showed that DMNA induced free radical generation mainly in the cytosol. Preincubation of HepG2 cells with N-acetylcysteine and 2,2'-dipyridyl significantly prevented free radical generation on subsequent incubation with DMNA, whereas preincubation with apocynin and dimethyl sulfoxide had no effect. These results suggest that DMNA is metabolized to reactive free radicals capable of generating protein radicals which may play a critical role in DMNA toxicity. We propose that the captodative effect, the combined action of the electron-releasing dimethylamine substituent, and the electron-withdrawing nitroso substituent, leads to a thermodynamically stabilized radical, facilitating enhanced protein radical formation by DMNA. Copyright © 2014 Elsevier Inc. All rights reserved.

Homegrown religious radicalization

DEFF Research Database (Denmark)

Khawaja, Iram

It has been reported that a growing number of youngsters from Western Europe are engaging in conflicts motivated by religious and political conflicts in the Middle East. This paper explores the reasons behind this seemingly religious radicalization from the point of view of the youngsters...... youngsters and parents of youngsters who have chosen a radicalized path in life. The paper will shed light on how the sense of and yearning for belonging and recognition have to be taken into account in our understanding of homegrown religious radicalization...

Encouraging conceptual change: the use of bridging analogies in the teaching of action reaction forces and the `at rest' condition in physics

Science.gov (United States)

Bryce, Tom; MacMillan, Kenneth

2005-06-01

The qualitative study described in this paper examined the effectiveness of bridging analogies intended to bring about conceptual change as part of a constructivist approach to teaching about action reaction forces in the ‘at rest’ condition in physics. Twenty-one 15-year-old students were involved in the investigation with subgroups previously exposed to different information regarding forces, weight and the accepted cause of the reaction force, in simple physical arrangements, including objects on tables. In-depth ‘think aloud’ interviews were used to track each student’s conceptual status as they worked with bridging analogies and transcript coding was carried out using open and axial coding (as in a grounded theory methodology). The findings showed that the bridging analogies were effective in engaging students with the idea of action reaction forces; students were adept in mapping each of the analogies to the target concept and using them to generate and refine their causal theories for the reaction force. There was evidence to suggest that, for some students, bridging analogies were more effective in bringing about conceptual change than didactic teaching. Their use extends beyond illustrative purposes and supports the development of meta-cognitive skills.

Conceptual models in the field of library catalogues

Directory of Open Access Journals (Sweden)

Marija Petek

2000-01-01

Full Text Available The publishing world is changing quickly and so must also bibliographic control. It is tirne to re-examine cataloguing rules and MARC formats. This can be done by the method of conceptual modelling. Some conceptual models are presented; an IFLA study on the functional requirements for bibliographic records is described in detail.

Laparoscopic radical trachelectomy.

Science.gov (United States)

Rendón, Gabriel J; Ramirez, Pedro T; Frumovitz, Michael; Schmeler, Kathleen M; Pareja, Rene

2012-01-01

The standard treatment for patients with early-stage cervical cancer has been radical hysterectomy. However, for women interested in future fertility, radical trachelectomy is now considered a safe and feasible option. The use of minimally invasive surgical techniques to perform this procedure has recently been reported. We report the first case of a laparoscopic radical trachelectomy performed in a developing country. The patient is a nulligravid, 30-y-old female with stage IB1 adenocarcinoma of the cervix who desired future fertility. She underwent a laparoscopic radical trachelectomy and bilateral pelvic lymph node dissection. The operative time was 340 min, and the estimated blood loss was 100mL. There were no intraoperative or postoperative complications. The final pathology showed no evidence of residual disease, and all pelvic lymph nodes were negative. At 20 mo of follow-up, the patient is having regular menses but has not yet attempted to become pregnant. There is no evidence of recurrence. Laparoscopic radical trachelectomy with pelvic lymphadenectomy in a young woman who desires future fertility may also be an alternative technique in the treatment of early cervical cancer in developing countries.

MISCONCEPTIONS AND NON-SCIENTIFIC CONCEPTS ON FREE RADICALS

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Rosiris Sindeaux de Alencar Pires de Oliveira

2016-11-01

Full Text Available INTRODUCTION: Misconceptions or alternative conceptions are defined as conceptions that are somewhat different from the scientifically accepted ones and are known to be highly resistant to changes. Free radicals are a widely publicized subject in the media due to their putative importance in human aging and health. Free radicals are a subject susceptible to misconceptions widely spread by the media supporting prejudicial advertising inducing antioxidant consumption. OBJECTIVES: Identify and categorized different free radicals misconceptions published in printed media. MATERIALS AND METHODS: Revista Veja (Digital Archive, the weekly magazine with the largest circulation in Brazil, was selected for this investigation. Period analyzed: from 01/01/2000 to 31/07/2014 with search terms Free radicals and antioxidants. Passages selected were classified as: Right Concept (RC, Wrong Concept (WC, Misconception (MC, Inadequate generalization (IG, Inductive [to misconceptions] Concept (IC, Inductive [to misconceptions] Information (II, and Not fit the inclusion criteria (NFIC. Each one of these categories were further subdivided. DISCUSSION AND RESULTS: 79 magazine articles, advertisements and information materials were found which led to 293 text passages. 56.3% were MC, 21.4% II, 8.8% IC, 5.4% IG, 3.4% RC, 2.7% WR, 2.0% NFIC. The most frequently subcategory in each category was: MC: x [something] combats free radicals (22.6%; II: x [substance] is antioxidant (54.0%; IC: x [something] increases free radicals production (34.6%; IG: antioxidant x [substance] combats cancer (56.3%; RC: too much vitamins and minerals is harmful to health (30.0%; WR: free radicals are formed during oxygen conversion to energy process (25.0%. CONCLUSION: Magazine analysis reveal non-scientific concepts (MC, II, IC and IG to be highly frequent, notably misconceptions. Moreover, non-scientific concepts together reach 91.8% of all concepts while right concepts respond for only 2

Triple-loop learning as foundation for profound change, individual cultivation, and radical innovation. Construction processes beyond scientific and rational knowledge.

OpenAIRE

Peschl, Markus F.

2007-01-01

Purpose: Ernst von Glasersfeld’s question concerning the relationship between scientific/ rational knowledge and the domain of wisdom and how these forms of knowledge come about is the starting point. This article aims at developing an epistemological as well as methodological framework that is capable of explaining how profound change can be brought about in various contexts, such as in individual cultivation, in organizations, in processes of radical innovation, etc. This fra...

Radical Evil

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Carlos Manrique

2007-12-01

Full Text Available There is an aporia in Kant’s analysis of evil: he defines radical evilas an invisible disposition of the will, but he also demands an inferential connection between visible evil actions and this invisible disposition. This inference,however, undermines the radical invisibility of radical evil according to Kant’s own definition of the latter. Noting how this invisibility of moral worth is a distinctive feature of Kant’s approach to the moral problem, the paper then asks why, in the Groundwork, he nonetheless forecloses a question about evil that seems to be consistent with this approach. It is argued that to account for this aporia and this foreclosure, one has to interrogate the way in which the category of religion orients Kant’s incipient philosophy of history in Die Religion.

Simulating runoff under changing climatic conditions: Revisiting an apparent deficiency of conceptual rainfall-runoff models

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Fowler, Keirnan J. A.; Peel, Murray C.; Western, Andrew W.; Zhang, Lu; Peterson, Tim J.

2016-03-01

Hydrologic models have potential to be useful tools in planning for future climate variability. However, recent literature suggests that the current generation of conceptual rainfall runoff models tend to underestimate the sensitivity of runoff to a given change in rainfall, leading to poor performance when evaluated over multiyear droughts. This research revisited this conclusion, investigating whether the observed poor performance could be due to insufficient model calibration and evaluation techniques. We applied an approach based on Pareto optimality to explore trade-offs between model performance in different climatic conditions. Five conceptual rainfall runoff model structures were tested in 86 catchments in Australia, for a total of 430 Pareto analyses. The Pareto results were then compared with results from a commonly used model calibration and evaluation method, the Differential Split Sample Test. We found that the latter often missed potentially promising parameter sets within a given model structure, giving a false negative impression of the capabilities of the model. This suggests that models may be more capable under changing climatic conditions than previously thought. Of the 282[347] cases of apparent model failure under the split sample test using the lower [higher] of two model performance criteria trialed, 155[120] were false negatives. We discuss potential causes of remaining model failures, including the role of data errors. Although the Pareto approach proved useful, our aim was not to suggest an alternative calibration strategy, but to critically assess existing methods of model calibration and evaluation. We recommend caution when interpreting split sample results.

Using inquiry-based instruction with Web-based data archives to facilitate conceptual change about tides among preservice teachers

Science.gov (United States)

Ucar, Sedat

understanding. Also, after completion of the inquiry-based and technology-enhanced instruction, some preservice teachers were likely to continue to hold the conception that the rotation of the moon around the Earth during one 24-hour period causes the tides to move with the moon. The findings of the study provide evidence that inquiry-based and technology-enhanced instruction utilizing Web-based archived data sources can be used to promoting conceptual change among preservice teachers.

Radical constructivism: Between realism and solipsism

Science.gov (United States)

Martínez-Delgado, Alberto

2002-11-01

This paper criticizes radical constructivism of the Glasersfeld type, pointing out some contradictions between the declared radical principles and their theoretical and practical development. These contradictions manifest themselves in a frequent oscillation between solipsism and realism, despite constructivist claims to be an anti-realist theory. The paper also points out the contradiction between the relativism of the radical constructivist principles and the constructivist exclusion of other epistemological or educational paradigms. It also disputes the originality and importance of the radical constructivist paradigm, suggesting the idea of an isomorphism between radical constructivist theory and contemplative realism. In addition, some pedagogical and scientific methodological aspects of the radical constructivist model are examined. Although radical constructivism claims to be a rational theory and advocates deductive thinking, it is argued that there is no logical deductive connection between the radical principles of constructivism and the radical constructivist ideas about scientific research and learning. The paper suggests the possibility of an ideological substratum in the construction and hegemonic success of subjective constructivism and, finally, briefly advances an alternative realist model to epistemological and educational radical constructivism.

People, plants and health: a conceptual framework for assessing changes in medicinal plant consumption

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Smith-Hall Carsten

2012-11-01

Full Text Available Abstract Background A large number of people in both developing and developed countries rely on medicinal plant products to maintain their health or treat illnesses. Available evidence suggests that medicinal plant consumption will remain stable or increase in the short to medium term. Knowledge on what factors determine medicinal plant consumption is, however, scattered across many disciplines, impeding, for example, systematic consideration of plant-based traditional medicine in national health care systems. The aim of the paper is to develop a conceptual framework for understanding medicinal plant consumption dynamics. Consumption is employed in the economic sense: use of medicinal plants by consumers or in the production of other goods. Methods PubMed and Web of Knowledge (formerly Web of Science were searched using a set of medicinal plant key terms (folk/peasant/rural/traditional/ethno/indigenous/CAM/herbal/botanical/phytotherapy; each search terms was combined with terms related to medicinal plant consumption dynamics (medicinal plants/health care/preference/trade/treatment seeking behavior/domestication/sustainability/conservation/urban/migration/climate change/policy/production systems. To eliminate studies not directly focused on medicinal plant consumption, searches were limited by a number of terms (chemistry/clinical/in vitro/antibacterial/dose/molecular/trial/efficacy/antimicrobial/alkaloid/bioactive/inhibit/antibody/purification/antioxidant/DNA/rat/aqueous. A total of 1940 references were identified; manual screening for relevance reduced this to 645 relevant documents. As the conceptual framework emerged inductively, additional targeted literature searches were undertaken on specific factors and link, bringing the final number of references to 737. Results The paper first defines the four main groups of medicinal plant users (1. Hunter-gatherers, 2. Farmers and pastoralists, 3. Urban and peri-urban people, 4. Entrepreneurs and

People, plants and health: a conceptual framework for assessing changes in medicinal plant consumption.

Science.gov (United States)

Smith-Hall, Carsten; Larsen, Helle Overgaard; Pouliot, Mariève

2012-11-13

A large number of people in both developing and developed countries rely on medicinal plant products to maintain their health or treat illnesses. Available evidence suggests that medicinal plant consumption will remain stable or increase in the short to medium term. Knowledge on what factors determine medicinal plant consumption is, however, scattered across many disciplines, impeding, for example, systematic consideration of plant-based traditional medicine in national health care systems. The aim of the paper is to develop a conceptual framework for understanding medicinal plant consumption dynamics. Consumption is employed in the economic sense: use of medicinal plants by consumers or in the production of other goods. PubMed and Web of Knowledge (formerly Web of Science) were searched using a set of medicinal plant key terms (folk/peasant/rural/traditional/ethno/indigenous/CAM/herbal/botanical/phytotherapy); each search terms was combined with terms related to medicinal plant consumption dynamics (medicinal plants/health care/preference/trade/treatment seeking behavior/domestication/sustainability/conservation/urban/migration/climate change/policy/production systems). To eliminate studies not directly focused on medicinal plant consumption, searches were limited by a number of terms (chemistry/clinical/in vitro/antibacterial/dose/molecular/trial/efficacy/antimicrobial/alkaloid/bioactive/inhibit/antibody/purification/antioxidant/DNA/rat/aqueous). A total of 1940 references were identified; manual screening for relevance reduced this to 645 relevant documents. As the conceptual framework emerged inductively, additional targeted literature searches were undertaken on specific factors and link, bringing the final number of references to 737. The paper first defines the four main groups of medicinal plant users (1. Hunter-gatherers, 2. Farmers and pastoralists, 3. Urban and peri-urban people, 4. Entrepreneurs) and the three main types of benefits (consumer, producer

An Explanation for the Difficulty of Leading Conceptual Change Using a Counterintuitive Demonstration: The Relationship between Cognitive Conflict and Responses

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Lee, Gyoungho; Byun, Taejin

2012-01-01

Bringing successful teaching approaches for stimulating conceptual change to normal classrooms has been a major challenge not only for teachers but also for researchers. In this study, we focused on the relationship between cognitive conflict and responses to anomalous data when students are confronted with a counterintuitive demonstration in the…

The role of the nurse in the rehabilitation of patients with radical changes in body image due to burn injuries.

Science.gov (United States)

Aacovou, I

2005-06-30

Burn injuries are among the most serious causes of radical changes in body image. The subject of body image and self-image is essential in rehabilitation, and the nurse must be aware of the issues related to these concepts and take them seriously into account in drafting out the nursing programme. This paper defines certain key words related to body image and discusses the social context of body image. Burn injuries are considered in relation to the way each of these affects the patient's body image. The aim of nursing is defined and the nurse's role in cases of severe changes in body image due to burn injuries is discussed.

Radical Decisions in Cancer: Redox Control of Cell Growth and Death

International Nuclear Information System (INIS)

Sainz, Rosa M.; Lombo, Felipe; Mayo, Juan C.

2012-01-01

Free radicals play a key role in many physiological decisions in cells. Since free radicals are toxic to cellular components, it is known that they cause DNA damage, contribute to DNA instability and mutation and thus favor carcinogenesis. However, nowadays it is assumed that free radicals play a further complex role in cancer. Low levels of free radicals and steady state levels of antioxidant enzymes are responsible for the fine tuning of redox status inside cells. A change in redox state is a way to modify the physiological status of the cell, in fact, a more reduced status is found in resting cells while a more oxidative status is associated with proliferative cells. The mechanisms by which redox status can change the proliferative activity of cancer cells are related to transcriptional and posttranscriptional modifications of proteins that play a critical role in cell cycle control. Since cancer cells show higher levels of free radicals compared with their normal counterparts, it is believed that the anti-oxidative stress mechanism is also increased in cancer cells. In fact, the levels of some of the most important antioxidant enzymes are elevated in advanced status of some types of tumors. Anti-cancer treatment is compromised by survival mechanisms in cancer cells and collateral damage in normal non-pathological tissues. Though some resistance mechanisms have been described, they do not yet explain why treatment of cancer fails in several tumors. Given that some antitumoral treatments are based on the generation of free radicals, we will discuss in this review the possible role of antioxidant enzymes in the survival mechanism in cancer cells and then, its participation in the failure of cancer treatments

Comparison between Two Bromine Containing Free Radical Initiators in PRESAGE®

Energy Technology Data Exchange (ETDEWEB)

Park, Hyeonsuk; Ryu, Dongmin; Ye, Sung-Joon [Seoul National University, Seoul (Korea, Republic of)

2016-10-15

PRESAGE® is an optically clear 3-D polyurethane dosimeter which contains a halogenated carbon as a free radical initiator and leucomalachite dye. The change of the optical density is known to be linear with respect to the absorbed dose and the sensitivity is related to the carbon–halogen bond dissociation energy of the free radical initiator. Although there are some studies regarding free radical initiators and dye materials, there’s a lack of reports about the effect of other elements like LMG solvent which can be added when there’s a difficulty mixing materials. Also, there are some studies about comparison between free radicals with different kind of halogen atoms but there’s a lack of studies of comparison between initiators with the same halogen atom. In this experiments, two kinds of halocarbon free radical initiator with the same halogen atom (bromine) as well as the effect of the LMG solvent were studied to use the dosimeter as a therapeutic purpose. Effective atomic numbers were also calculated. The initiators with the same halogen atom, CBr{sub 4} and C{sub 2}H{sub 2}Br{sub 4}, reacted totally differently. CBr{sub 4} was more sensitive to the radiation and emitted maximum 4 times more free radicals upon irradiation with no additional effective atomic number but the absorbance after irradiation was highly variable with time. For stable measurement, C{sub 2}H{sub 2}Br{sub 4} would be more appropriate as a free radical initiator.

Transformations of dissolved organic matter induced by UV photolysis, Hydroxyl radicals, chlorine radicals, and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes.

Science.gov (United States)

Varanasi, Lathika; Coscarelli, Erica; Khaksari, Maryam; Mazzoleni, Lynn R; Minakata, Daisuke

2018-05-15

Considering the increasing identification of trace organic contaminants in natural aquatic environments, the removal of trace organic contaminants from water or wastewater discharge is an urgent task. Ultraviolet (UV) and UV-based advanced oxidation processes (AOPs), such as UV/hydrogen peroxide (UV/H 2 O 2 ), UV/free chlorine and UV/persulfate, are attractive and promising approaches for the removal of these contaminants due to the high reactivity of active radical species produced in these UV-AOPs with a wide variety of organic contaminants. However, the removal efficiency of trace contaminants is greatly affected by the presence of background dissolved organic matter (DOM). In this study, we use ultrahigh resolution mass spectrometry to evaluate the transformation of a standard Suwanee River fulvic acid DOM isolate in UV photolysis and UV-AOPs. The use of probe compounds allows for the determination of the steady-state concentrations of active radical species in each UV-AOP. The changes in the H/C and O/C elemental ratios, double bond equivalents, and the low-molecular-weight transformation product concentrations of organic acids reveal that different DOM transformation patterns are induced by each UV-AOP. By comparison with the known reactivities of each radical species with specific organic compounds, we mechanistically and systematically elucidate the molecular-level DOM transformation pathways induced by hydroxyl, chlorine, and sulfate radicals in UV-AOPs. We find that there is a distinct transformation in the aliphatic components of DOM due to HO• in UV/H 2 O 2 and UV/free chlorine. Cl• induced transformation of olefinic species is also observed in the UV/free chlorine system. Transformation of aromatic and olefinic moieties by SO 4 •- are the predominant pathways in the UV/persulfate system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of water and ethanol radicals on the protein part of human hemoglobin

International Nuclear Information System (INIS)

Szweda-Lewandowska, Z.; Puchala, M.

1989-01-01

This paper studies the changes in the tryptophan fluorescence in human hemoglobin induced by ·OH, e aq - , H atoms and ethanol radicals. Measurements of irradiated hemoglobin performed in phosphate buffer, pH 7, indicate that the processes of unfolding a protein are induced with the highest efficiency by the ·OH radicals. A destructive action of e aq - is more evident in the absence of the ·OH radicals. Fluorescence measurements carried out after incubation of irradiated hemoglobin in Gdn·HCl solution reveal the tryptophan residues destruction, which is relatively small (at 2.5 kGy maximum fluorescence decrease was about 23%) and caused by the ·OH radicals. Within the dose range, the participation of the e aq - , H atoms and ethanol radicals in hemoglobin tryptophan residue destruction can be neglected. (author)

The Radical Flank Effect and Cross-occupational Collaboration for Technology Development during a Power Shift

Science.gov (United States)

Truelove, Emily; Kellogg, Katherine C.

2016-01-01

This 12-month ethnographic study of an early entrant into the U.S. car-sharing industry demonstrates that when an organization shifts its focus from developing radical new technology to incrementally improving this technology, the shift may spark an internal power struggle between the dominant engineering group and a challenger occupational group such as the marketing group. Analyzing 42 projects in two time periods that required collaboration between engineering and marketing during such a shift, we show how cross-occupational collaboration under these conditions can be facilitated by a radical flank threat, through which the bargaining power of moderates is strengthened by the presence of a more-radical group. In the face of a strong threat by radical members of a challenger occupational group, moderate members of the dominant engineering group may change their perceptions of their power to resist challengers’ demands and begin to distinguish between the goals of radical versus more-moderate challengers. To maintain as much power as possible and prevent the more-dramatic change in engineering occupational goals demanded by radical challengers, moderate engineers may build a coalition with moderate challengers and collaborate for incremental technology development. PMID:28424533

The Radical Flank Effect and Cross-occupational Collaboration for Technology Development during a Power Shift.

Science.gov (United States)

Truelove, Emily; Kellogg, Katherine C

2016-12-01

This 12-month ethnographic study of an early entrant into the U.S. car-sharing industry demonstrates that when an organization shifts its focus from developing radical new technology to incrementally improving this technology, the shift may spark an internal power struggle between the dominant engineering group and a challenger occupational group such as the marketing group. Analyzing 42 projects in two time periods that required collaboration between engineering and marketing during such a shift, we show how cross-occupational collaboration under these conditions can be facilitated by a radical flank threat, through which the bargaining power of moderates is strengthened by the presence of a more-radical group. In the face of a strong threat by radical members of a challenger occupational group, moderate members of the dominant engineering group may change their perceptions of their power to resist challengers' demands and begin to distinguish between the goals of radical versus more-moderate challengers. To maintain as much power as possible and prevent the more-dramatic change in engineering occupational goals demanded by radical challengers, moderate engineers may build a coalition with moderate challengers and collaborate for incremental technology development.

The determination of the radical power - an in vitro test for the evaluation of cosmetic products.

Science.gov (United States)

Herrling, T; Seifert, M; Sandig, G; Jung, K

2016-06-01

Cosmetic formulations are influenced by environmental impacts and ageing, resulting in rancidity and change of colour and structure. These changes are caused by free radicals (FRs). The sensitivity of cosmetics generating FRs is a metric for its quality and should be determined. Electron spin resonance spectroscopy in combination with UV irradiation tested cosmetics such as creams, milks, lotions and fragrances. The probes were directly measured without expensive preparation. Nine formulations are tested for its radical generation and ranked corresponding to the radical power. The transformation of the FR properties of three formulations to skin is measured by the radical skin status factor (RSF) method. It shows that the higher the radical power (RP) is, the lower the radical status RSF of skin will be. The knowledge of the sensitivity of cosmetics to generate FRs is necessary for its stabilization and prevention of potential damages to skin. It is a new way in development of cosmetics which has to be considered. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Analysis of radicals induced in irradiated cereal flour using ESR

International Nuclear Information System (INIS)

Kawamura, Shoei; Kishita, Keigo; Ukai, Mitsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko

2013-01-01

Using electron spin resonance (ESR) spectroscopy, we revealed radicals induced in cereal flour irradiated with gamma-ray or electron beam. Sample was wheat and rice. We detected a broad singlet signal at g = 2.0. It consists of a singlet signal and a triplet signal. It suggested that the singlet signal is originated from organic free radicals and the triplet signal is from 14 N. There were no differences of ESR spectra between irradiated wheat flour and rice flour. The signal intensity of radiation induced radical was tend to increase following with the increase of radiation dose level. After radiation treatment, relaxation time of radiation induced radical was changed during storage. T 1 was decreased and T 2 was increased. In this study, the relaxation time is calculated using the parameters obtained from the ESR signal. It is necessary to analyze the relaxation time directly with pulsed ESR spectroscopy in future. (author)

Meaningful learning: The essential factor for conceptual change in limited or inappropriate propositional hierarchies leading to empowerment of learners

Science.gov (United States)

Novak, Joseph D.

2002-07-01

The construction and reconstruction of meanings by learners requires that they actively seek to integrate new knowledge with knowledge already in their cognitive structure. Ausubel's assimilation theory of cognitive learning has been shown to be effective in guiding research and instructional design to facilitate meaningful learning (Ausubel, The psychology of meaningful verbal learning, New York: Grune and Stratton, 1963; Educational psychology: A cognitive view, New York: Holt, Rinehart and Winston, 1968; The acquisition and retention of knowledge, Dordrecht: Kluwer, 2000). Gowin's Vee heuristic has been employed effectively to aid teachers and students in understanding the constructed nature of knowledge (Gowin, Educating, Ithaca, NY: Cornell University Press, 1981). Situated learning occurs when learning is by rote or at a lower level of meaningful learning. Concept mapping has been used effectively to aid meaningful learning with resulting modification of student's knowledge structures. When these knowledge structures are limited or faulty in some way, they may be referred to as Limited or Inappropriate Propositional Hierarchies (LIPH's). Conceptual change, or more accurately conceptual reconstrution, requires meaningful learning to modify LIPH's. Collaborative group learning facilitates meaningful learning and new knowledge construction. World-wide economic changes are forcing major changes in business and industry placing a premium on the power and value of knowledge and new knowledge production. These changes require changes in school and university education that centers on the nature and power of meaningful learning. New computer tools are available to facilitate teaching activities targeted at modifying LIPH's, and aiding meaningful learning in general.

Salvage robotic radical prostatectomy

Directory of Open Access Journals (Sweden)

Samuel D Kaffenberger

2014-01-01

Full Text Available Failure of non-surgical primary treatment for localized prostate cancer is a common occurrence, with rates of disease recurrence ranging from 20% to 60%. In a large proportion of patients, disease recurrence is clinically localized and therefore potentially curable. Unfortunately, due to the complex and potentially morbid nature of salvage treatment, radical salvage surgery is uncommonly performed. In an attempt to decrease the morbidity of salvage therapy without sacrificing oncologic efficacy, a number of experienced centers have utilized robotic assistance to perform minimally invasive salvage radical prostatectomy. Herein, we critically evaluate the existing literature on salvage robotic radical prostatectomy with a focus on patient selection, perioperative complications and functional and early oncologic outcomes. These results are compared with contemporary and historical open salvage radical prostatectomy series and supplemented with insights we have gained from our experience with salvage robotic radical prostatectomy. The body of evidence by which conclusions regarding the efficacy and safety of robotic salvage radical prostatectomy can be drawn comprises fewer than 200 patients with limited follow-up. Preliminary results are promising and some outcomes have been favorable when compared with contemporary open salvage prostatectomy series. Advantages of the robotic platform in the performance of salvage radical prostatectomy include decreased blood loss, short length of stay and improved visualization. Greater experience is required to confirm the long-term oncologic efficacy and functional outcomes as well as the generalizability of results achieved at experienced centers.

Computational study of the structure-free radical scavenging relationship of procyanidins.

Science.gov (United States)

Mendoza-Wilson, Ana María; Castro-Arredondo, Sergio Ivan; Balandrán-Quintana, René Renato

2014-10-15

Procyanidins (PCs) are effective free radical scavengers, however, their antioxidant ability is variable because they have different degrees of polymerisation, are composed by distinct types of subunits and are very susceptible to changes in conformation. In this work the structure-free radical scavenging relationship of monomers, dimers and trimers of PCs was studied through the hydrogen atom transfer (HAT), sequential proton-loss electron-transfer (SPLET) and single electron transfer followed by proton transfer (SET-PT) mechanisms in aqueous phase, employing the Density Functional Theory (DFT) computational method. The structure-free radical scavenging relationship of PCs showed a very similar behaviour in HAT and SET-PT mechanisms, but very different in the SPLET mechanism. The structural factor that showed more effects on the ability of PCs to scavenge free radicals in aqueous phase was the conformation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Muoniated acyl and thioacyl radicals

International Nuclear Information System (INIS)

McKenzie, Iain; Brodovitch, Jean-Claude; Ghandi, Khashayar; Percival, Paul W.

2006-01-01

The product of the reaction of muonium with tert-butylisocyanate was previously assigned as the muoniated tert-butylaminyl radical (I. McKenzie, J.-C. Brodovitch, K. Ghandi, S. Kecman, P. W. Percival, Physica B 326 (2003) 76). This assignment is incorrect since the muon and 14 N hyperfine-coupling constants (hfcc) of this radical would have the opposite sign, which is in conflict with the experimental results. The radical is now reassigned as the muoniated N-tert-butylcarbamoyl radical, based on the similarities between the experimental muon and 14 N hfcc and hfcc calculated at the UB3LYP/6-311G(d,p)//UB3LYP/EPR-III level. The large zero-point energy in the N-Mu bond results in the dissociation barrier of the muoniated N-tert-butylcarbamoyl radical being above the combined energy of the reactants, in contrast to the N-tert-butylcarbamoyl radical where the dissociation barrier lies below the combined energy of the reactants. The reaction of muonium with tert-butylisothiocyanate produced both conformers of the muoniated N-tert-butylthiocarbamoyl radical and their assignment was based on the similarities between the experimental and calculated muon hfcc. These are the first acyl and thioacyl radicals to be directly detected by muon spin spectroscopy

Muoniated acyl and thioacyl radicals

Energy Technology Data Exchange (ETDEWEB)

McKenzie, Iain [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Brodovitch, Jean-Claude [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Ghandi, Khashayar [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Percival, Paul W. [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada)]. E-mail: percival@sfu.ca

2006-03-31

The product of the reaction of muonium with tert-butylisocyanate was previously assigned as the muoniated tert-butylaminyl radical (I. McKenzie, J.-C. Brodovitch, K. Ghandi, S. Kecman, P. W. Percival, Physica B 326 (2003) 76). This assignment is incorrect since the muon and {sup 14}N hyperfine-coupling constants (hfcc) of this radical would have the opposite sign, which is in conflict with the experimental results. The radical is now reassigned as the muoniated N-tert-butylcarbamoyl radical, based on the similarities between the experimental muon and {sup 14}N hfcc and hfcc calculated at the UB3LYP/6-311G(d,p)//UB3LYP/EPR-III level. The large zero-point energy in the N-Mu bond results in the dissociation barrier of the muoniated N-tert-butylcarbamoyl radical being above the combined energy of the reactants, in contrast to the N-tert-butylcarbamoyl radical where the dissociation barrier lies below the combined energy of the reactants. The reaction of muonium with tert-butylisothiocyanate produced both conformers of the muoniated N-tert-butylthiocarbamoyl radical and their assignment was based on the similarities between the experimental and calculated muon hfcc. These are the first acyl and thioacyl radicals to be directly detected by muon spin spectroscopy.

Zero-Point Corrections for Isotropic Coupling Constants for Cyclohexadienyl Radical, C6H7 and C6H6Mu: Beyond the Bond Length Change Approximation

Directory of Open Access Journals (Sweden)

Bruce S. Hudson

2013-04-01

Full Text Available Zero-point vibrational level averaging for electron spin resonance (ESR and muon spin resonance (µSR hyperfine coupling constants (HFCCs are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on 13C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C6H7, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH2 of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0, can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

Muonium and muonic radicals

International Nuclear Information System (INIS)

Burkhard, P.; Fischer, H.; Roduner, E.; Strub, W.; Geeson, D.; Symons, M.C.R.

1985-01-01

An energetic positive muon which is injected in a liquid sample of substrate molecules (S) creates an ionization track consisting of substrate cations (S + ) and electrons. Near the end of this track the muon may combine with an electron to form muonium (Mu) which is observable in inert liquids, but which reacts by addition to form a radical. Alternatively, the electron can add to S to form S - , which then combines with the muon to form the radical. Furthermore, instead of ending up in Mu or in a radical the muon may stay in a diamagnetic environment as a solvated muon, or as a muon substituting a proton in a molecule. Of interest in these schemes are the mechanisms and rates of formation of muonated radicals and in particular the rate constants for their reactions to products. Investigations are based on the observation of Mu and the radical by means of the μSR technique in transverse magnetic fields. (Auth.)

A zero-dimensional approach to compute real radicals

Directory of Open Access Journals (Sweden)

Silke J. Spang

2008-04-01

Full Text Available The notion of real radicals is a fundamental tool in Real Algebraic Geometry. It takes the role of the radical ideal in Complex Algebraic Geometry. In this article I shall describe the zero-dimensional approach and efficiency improvement I have found during the work on my diploma thesis at the University of Kaiserslautern (cf. [6]. The main focus of this article is on maximal ideals and the properties they have to fulfil to be real. New theorems and properties about maximal ideals are introduced which yield an heuristic prepare_max which splits the maximal ideals into three classes, namely real, not real and the class where we can't be sure whether they are real or not. For the latter we have to apply a coordinate change into general position until we are sure about realness. Finally this constructs a randomized algorithm for real radicals. The underlying theorems and algorithms are described in detail.

Leghemoglobin-derived radicals. Evidence for multiple protein-derived radicals and the initiation of peribacteroid membrane damage

DEFF Research Database (Denmark)

Moreau, S; Davies, Michael Jonathan; Mathieu, C

1996-01-01

, with the consequent generation of lipid-derived radicals. The formation of such radicals may result in the depletion of membrane antioxidants and the initiation of lipid peroxidation. This transfer of damage from the heme center via the protein surface to neighboring membranes may be of considerable biological......-derived phenoxyl radical present at Tyr-133 in the soybean protein and Tyr-138 in the lupin protein. To obtain further information on these protein radicals and their potential interaction with the physiologically important peribacteroid membrane (which surrounds the microsymbiont in vivo), EPR spin trapping......); these radicals may be side chain- or alpha-carbon-derived, their exact sites have not been determined. Some of these radicals are on the protein surface and may be key intermediates in the formation of protein dimers. These radicals have been shown to be capable of reacting with peribacteroid membrane fractions...

Studies of radiation-produced radicals and radical ions. Progress report, June 1, 1981-August 31, 1982

International Nuclear Information System (INIS)

Williams, T.F.

1982-01-01

The discovery and characterization of novel radical ions produced by the γ irradiation of solids continues to be a fertile field for investigation. This Progress Report describes the generation and ESR identification of several new paramagnetic species, some of which have long been sought as important intermediates in radiation chemistry. We have also contributed to a general theoretical problem in ESR spectroscopy. Solid-state studies of electron attachment reactions, both non-dissociative and dissociative, reveal interesting structural and chemical information about the molecular nature of these processes for simple compounds. In particular, ESR measurements of the spin distribution in the products allow a fairly sharp distinction to be drawn between radical anions and radical-anion pairs or adducts. Dimer radical anion formation can also take place but the crystal structure plays a role in this process, as expected. Some radical anions undergo photolysis to give radical-anion pairs which may then revert back to the original radical anion by a thermal reaction. The chemistry of these reversible processes is made more intricate by a competing reaction in which the radical abstracts a hydrogen atom from a neighboring molecule. However, the unraveling of this complication has also served to extend our knowledge of the role of quantum tunneling in chemical reactions. The results of this investigation testify to the potential of solid-state techniques for the study of novel and frangible radical ions. Progress in this field shows no sign of abating, as witness the recent discovery of perfluorocycloalkane radical anions and alkane radical cations

Using Theory of Mind to Promote Conceptual Change in Science

Science.gov (United States)

Kyriakopoulou, Natassa; Vosniadou, Stella

2014-01-01

We argue that learning science requires children to move from perceptually based representations to more abstract conceptual representations and to understand that appearance may sometimes deceive us and that the same phenomenon in the world can have more than one representation when seen from different perspectives. We also argue that the…

Radicals derived from acetaldehyde and vinyl alcohol.

Science.gov (United States)

Estep, Marissa L; Morgan, W James; Winkles, Alexander T; Abbott, Adam S; Villegas-Escobar, Nery; Mullinax, J Wayne; Turner, Walter E; Wang, Xiao; Turney, Justin M; Schaefer, Henry F

2017-10-18

Vinyl alcohol and acetaldehyde are isoelectronic products of incomplete butanol combustion. Along with the radicals resulting from the removal of atomic hydrogen or the hydroxyl radical, these species are studied here using ab initio methods as complete as coupled cluster theory with single, double, triple, and perturbative quadruple excitations [CCSDT(Q)], with basis sets as large as cc-pV5Z. The relative energies provided herein are further refined by including corrections for relativistic effects, the frozen core approximation, and the Born-Oppenheimer approximation. The effects of anharmonic zero-point vibrational energies are also treated. The syn conformer of vinyl alcohol is predicted to be lower in energy than the anti conformer by 1.1 kcal mol -1 . The alcoholic hydrogen of syn-vinyl alcohol is found to be the easiest to remove, requiring 84.4 kcal mol -1 . Five other radicals are also carefully considered, with four conformers investigated for the 1-hydroxyvinyl radical. Beyond energetics, we have conducted an overhaul of the spectroscopic literature for these species. Our results also provide predictions for fundamental modes yet to be reported experimentally. To our knowledge, the ν 3 (3076 cm -1 ) and ν 4 (2999 cm -1 ) C-H stretches for syn-vinyl alcohol and all but one of the vibrational modes for anti-vinyl alcohol (ν 1 -ν 14 ) are yet to be observed experimentally. For the acetyl radical, ν 6 (1035 cm -1 ), ν 11 (944 cm -1 ), ν 12 (97 cm -1 ), and accounting for our changes to the assignment of the 1419.9 cm -1 experimental mode, ν 10 (1441 cm -1 ), are yet to be observed. We have predicted these unobserved fundamentals and reassigned the experimental 1419.9 cm -1 frequency in the acetyl radical to ν 4 rather than to ν 10 . Our work also strongly supports reassignment of the ν 10 and ν 11 fundamentals of the vinoxy radical. We suggest that the bands assigned to the overtones of these fundamentals were in fact combination bands. Our

Muonium-containing vinyl radicals

International Nuclear Information System (INIS)

Rhodes, C.J.; Symons, M.C.R.; Roduner, E.; Heming, M.

1987-01-01

Exposure of trimethylsilylacetylene and bis(trimethylsilyl)acetylene to positive muons gave radicals whose muon-electron hyperfine coupling constants establish that the corresponding vinyl radicals were formed. (author)

Radicals in arithmetic

NARCIS (Netherlands)

W.J. Palenstijn (Willem Jan)

2014-01-01

htmlabstractLet K be a field. A radical is an element of the algebraic closure of K of which a power is contained in K. In this thesis we develop a method for determining what we call entanglement. This describes unexpected additive relations between radicals, and is encoded in an entanglement

A/r/tographic Collaboration as Radical Relatedness

Directory of Open Access Journals (Sweden)

Barbara Bickel PhD

2011-03-01

Full Text Available In this paper the authors examine a/r/tographical collaboration in a community-engaged research study investigating immigrant understandings of home and place. The study, The City of Richgate, involves a complex collaboration between community members, community organizations, educational institutions, and a research team comprising artist-educators. The study crosses border zones of cultural, ethnic, geographic, institutional, public, private, and disciplinary boundaries, reflecting the ever-changing character of postmodern reality. In this paper the authors reflect critically and theoretically on the lived experience of radical relatedness found within the complex collaboration, particularly within the a/r/tographic research team. This offers a qualitative methodology of radical collaboration applicable to many fields of inquiry in the academy, art world, and community.

Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying

Science.gov (United States)

Abdul Hamid, Azizah; Pak Dek, Mohd Sabri; Tan, Chin Ping; Mohd Zainudin, Mohd Asraf; Wee Fang, Evelyn Koh

2014-01-01

Changes in antioxidant properties and degradation of bioactives in palm oil (PO) and rice bran oil (RBO) during deep-frying were investigated. The alpha (α)-tocopherol, gamma (γ)-tocotrienol and γ-oryzanol contents of the deep-fried oils were monitored using high performance liquid chromatography, and antioxidant activity was determined using 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Results revealed that the antioxidant activity of PO decreased significantly (p -oryzanol and γ-tocotrienol in RBO may have a protective effect on α-tocopherol during deep-frying. PMID:26785067

Preoperative radiochemotherapy and radical surgery in comparison with radical surgery alone

International Nuclear Information System (INIS)

Mohr, C.; Schettler, D.; Bohndorf, W.

1994-01-01

A multicentric, randomized study of squamous cell carcinoma (SCC) of the oral cavity and the oropharynx has been undertaken by DOeSAK. The results after radical surgery alone have been compared with the results of combined preoperative radiochemotherapy followed by radical surgery. Patients with primary (biopsy proven) SCC of the oral cavity or the oropharynx with tumor nodes metastasis (TNM) stages T2-4, N0-3, M0 were included in the study. A total of 141 patients were treated by radical surgery alone, whereas 127 patients were treated by radical surgery preceded by preoperative radiochemotherapy. The pre-operative treatment consisted of conventionally fractioned irradiation on the primary and the regional lymph nodes with a total dose of 36 Gy (5 x 2 Gy per week) and low-dose cisplatin chemotherapy with 5 x 12.5 mg cisplatin per m 2 of body surface during the first week of treatment. Radical surgery according to be DOeSAK definitions (DOeSAK, 1982) was performed after a delay of 10-14 days. During the follow-up period, 28.2% of all patients suffered from locoregional recurrence, and 27.2% of the patients died. The percentages were higher after radical surgery alone for locoregional recurrence (31% and 15.6%) and for death (28% and 18.6%). The life-table analysis showed improved survival rates of 4.5% after 1 year and 8.3% after 2 years in the group of patients treated with combined therapy. The demonstrated improvement appeared to be significant with the Gehan-Wilcoxon test as well as with the log rank test below a P value of 5%. (au) (29 refs.)

Radicals in arithmetic

NARCIS (Netherlands)

Palenstijn, Willem Jan

2014-01-01

Let K be a field. A radical is an element of the algebraic closure of K of which a power is contained in K. In this thesis we develop a method for determining what we call entanglement. This describes unexpected additive relations between radicals, and is encoded in an entanglement group. We give

Quantitative investigation of free radicals in bio-oil and their potential role in condensed-phase polymerization.

Science.gov (United States)

Kim, Kwang Ho; Bai, Xianglan; Cady, Sarah; Gable, Preston; Brown, Robert C

2015-03-01

We report on the quantitative analysis of free radicals in bio-oils produced from pyrolysis of cellulose, organosolv lignin, and corn stover by EPR spectroscopy. Also, we investigated their potential role in condensed-phase polymerization. Bio-oils produced from lignin and cellulose show clear evidence of homolytic cleavage reactions during pyrolysis that produce free radicals. The concentration of free radicals in lignin bio-oil was 7.5×10(20)  spin g(-1), which was 375 and 138 times higher than free-radical concentrations in bio-oil from cellulose and corn stover. Pyrolytic lignin had the highest concentration in free radicals, which could be a combination of carbon-centered (benzyl radicals) and oxygen-centered (phenoxy radicals) organic species because they are delocalized in a π system. Free-radical concentrations did not change during accelerated aging tests despite increases in molecular weight of bio-oils, suggesting that free radicals in condensed bio-oils are stable. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radicalization as a Vector: Exploring Non-Violent and Benevolent Processes of Radicalization.

Directory of Open Access Journals (Sweden)

Ken Reidy

2018-03-01

Full Text Available Successful radicalization posits three outcomes: extremism, terrorism or both. As these are undesirable, radicalization is understood as wholly malevolent and governments work to prevent and/or stop it. Nonetheless, a handful of scholars have recognized that the same radicalization process which results in either outcome may, theoretically at least, also have beneficial outcomes such as environmental awareness or human rights. This article explores one such outcome. Based on interviews with British Muslim aid workers (n=6 operating in Jihadist conflict zones post Arab spring and using constructivist grounded theory, it illustrates how the research participants radicalized to humanitarianism which resulted in them assisting the most plighted of Muslims by deploying to the most wanton of areas: ones commonly referred to as Jihadist conflict zones. Evidently, these destinations are shared with Jihadists and given the array of other observable similarities (socio-demographics and [pre-]mobilization behaviours, these morally opposed groups become conflated by the security services. This is further compounded by the fact that Jihadists manipulate and/or impersonate aid workers so as to funnel people and funds. To distinguish both, this article documents the benevolent pathway of the research participants and juxtaposes it to scholarly knowledge on Jihadist pathways. Socialization was revealed to be the key distinguishing feature rather than descriptive risk factors (such as ideology or moral outrage because the process of radicalization was not found to be the start of the radicalized pathway. It concludes that benevolently radicalized Islamic groups constitute an effective means of pathway divergence for particular typologies by offering an attractive and prosocial alternative to Jihadism. This strengths-based preventative approach (“what’s right” takes the form of a community-centric market competitor to Jihadism rather than a problem

Radical cations of quadricyclane and norbornadiene in polar ZSM-5 matrices: Radical cation photochemical transformations without photons

International Nuclear Information System (INIS)

Barnabas, M.V.; Trifunac, A.D.

1994-01-01

Radical cations of quadricyclane (Q) and norbornadiene (NBD) are produced by γ-radiolysis in zeolites. In polar ZSM-5, only one radical cation is initially observed below 100K. Increasing the temperature above 200K gives rise to the cyclopentadiene radical cation. Higher temperatures (>360K) give rise to the cyclopenten-4-yl radical. The observation of cyclopentadiene radical cation implies the occurrence of the reverse Diels-Alder reaction. This is a thermally forbidden, photochemically allowed, process, which is made possible by the interaction of the polar zeolite matrix sites with parent NBD and Q radical cations

Conceptual distortions of hand structure are robust to changes in stimulus information.

Science.gov (United States)

Ambroziak, Klaudia B; Tamè, Luigi; Longo, Matthew R

2018-05-01

Previous studies showed stereotyped distortions in hand representations. People judge their knuckles as farther forward in the hand than they actually are. The cause of this bias remains unclear. We tested whether both visual and tactile information contribute to the bias. In Experiment 1, participants judged the location of their knuckles by pointing to the location on their palm with: (1) a metal baton (using vision and touch), (2) a metal baton while blindfolded (using touch), or (3) a laser pointer (using vision). Distal mislocalisations were found in all conditions. In Experiment 2, we investigated whether judgments are influenced by visual landmarks such as creases. Participants localized their knuckles on either a photograph of their palm or a silhouette. Distal mislocalisations were apparent in both conditions. These results show that distal biases are resistant to changes in stimulus information, suggesting that such mislocalisations reflect a conceptual mis-representation of hand structure. Copyright © 2018 Elsevier Inc. All rights reserved.

The efficacy and utilisation of preoperative multiparametric magnetic resonance imaging in robot-assisted radical prostatectomy: does it change the surgical dissection plan?

Science.gov (United States)

Tavukçu, Hasan Hüseyin; Aytaç, Ömer; Balcı, Numan Cem; Kulaksızoğlu, Haluk; Atuğ, Fatih

2017-12-01

We investigated the effect of the use of multiparametric prostate magnetic resonance imaging (mp-MRI) on the dissection plan of the neurovascular bundle and the oncological results of our patients who underwent robot-assisted radical prostatectomy. We prospectively evaluated 60 consecutive patients, including 30 patients who had (Group 1), and 30 patients who had not (Group 2) mp-MRI before robot-assisted radical prostatectomy. Based on the findings of mp-MRI, the dissection plan was changed as intrafascial, interfascial, and extrafascial in the mp-MRI group. Two groups were compared in terms of age, prostate-specific antigen (PSA), Gleason sum scores and surgical margin positivity. There was no statistically significant difference between the two groups in terms of age, PSA, biopsy Gleason score, final pathological Gleason score and surgical margin positivity. mp-MRI changed the initial surgical plan in 18 of 30 patients (60%) in Group 1. In seventeen of these patients (56%) surgical plan was changed from non-nerve sparing to interfascial nerve sparing plan. In one patient dissection plan was changed to non-nerve sparing technique which had extraprostatic extension on final pathology. Surgical margin positivity was similar in Groups 1, and 2 (16% and 13%, respectively) although, Group 1 had higher number of high- risk patients. mp-MRI confirmed the primary tumour localisation in the final pathology in 27 of of 30 patients (90%). Preoperative mp-MRI effected the decision to perform a nerve-sparing technique in 56% of the patients in our study; moreover, changing the dissection plan from non-nerve-sparing technique to a nerve sparing technique did not increase the rate of surgical margin positivity.

Gestures: A Mode of Conceptualization in Science Gestures: A Mode of Conceptualization in Science

OpenAIRE

Givry , Damien; Roth , Wolff-Michael

2003-01-01

International audience; Problem Since the late 1970's there has been a lot of research to identify students' conceptions about physics (e.g., Pfundt & Duit, 1999). Now, more recent studies attempt to identify the factors that support the evolution of students' initial knowledge towards scientific knowledge. Among the studies of conceptual change (Posner, Strike, Hewson & Gertzog, 1982), we belong to small group of researchers that follow learning and change processes in real time, that is, "t...

Free radicals in chemical carcinogenesis.

Science.gov (United States)

Clemens, M R

1991-12-15

During the past decade, remarkable progress has been made in our understanding of cancer-causing agents, mechanisms of cancer formation and the behavior of cancer cells. Cancer is characterized primarily by an increase in the number of abnormal cells derived from a given normal tissue, invasion of adjacent tissues by these abnormal cells, and lymphatic or blood-borne spread of malignant cells to regional lymph nodes and to distant sites (metastasis). It has been estimated that about 75-80% of all human cancers are environmentally induced, 30-40% of them by diet. Only a small minority, possibly no more than 2% of all cases, result purely from inherent genetic changes. Several lines of evidence confirm that the fundamental molecular event or events that cause a cell to become malignant occur at the level of the DNA and a variety of studies indicate that the critical molecular event in chemical carcinogenesis is the interaction of the chemical agent with DNA. The demonstration that DNA isolated from tumor cells can transfect normal cells and render them neoplastic provides direct proof that an alteration of the DNA is responsible for cancer. The transforming genes, or oncogenes, have been identified by restriction endonuclease mapping. One of the characteristics of tumor cells generated by transformation with viruses, chemicals, or radiation is their reduced requirement for serum growth factors. A critical significance of electrophilic metabolites of carcinogenes in chemical carcinogenesis has been demonstrated. A number of "proximate" and "ultimate" metabolites, especially those of aromatic amines, were described. The "ultimate" forms of carcinogens actually interact with cellular constituents to cause neoplastic transformation and are the final metabolic products in most pathways. Recent evidence indicates that free radical derivatives of chemical carcinogens may be produced both metabolically and nonenzymatically during their metabolism. Free radicals carry no

Youth De-Radicalization: A Canadian Framework

Directory of Open Access Journals (Sweden)

Hafal (Haval Ahmad

2017-09-01

Full Text Available Youth radicalization leading to violence has become a growing fear among Canadians, as terrorist attacks are carried out in Western states. Although Canada has suffered relatively fewer acts of violence, this fear has intensified and a de-radicalization strategy is needed in the Canadian context. In a qualitative case study methodology, interviews were conducted with school counsellors, religious leaders, and academics to explore solutions to youth radicalization. Youth de-radicalization approaches from the United Kingdom were analyzed and found that community-based initiatives were missing from programming. Social identity theory is used to explain that youth join radicalized groups to feel a sense of belonging and have to be provided an alternative and moderate group identity to de-radicalize. This study found youth de-radicalization in Canada is best served through a community collaboration approach.

A conceptual framework for regional feedbacks in a changing climate

Science.gov (United States)

Batlle Bayer, L.; van den Hurk, B. J. J. M.; Strengers, B.

2012-04-01

Terrestrial ecosystems and climate influence each other through biogeochemical (e.g. carbon cycle) and biogeophysical (e.g. albedo, water fluxes) processes. These interactions might be disturbed when a climate human-induced forcing takes place (e.g. deforestation); and the ecosystem responses to the climate system might amplify (positive feedback) or dampen (negative feedback) the initial forcing. Research on feedbacks has been mainly based on the carbon cycle at the global scale. However, biogeophysical feedbacks might have a great impact at the local or regional scale, which is the main focus of this article. A conceptual framework, with the major interactions and processes between terrestrial ecosystems and climate, is presented to further explore feedbacks at the regional level. Four hot spots with potential changes in land use/management and climate are selected: sub-Saharan Africa (SSA), Europe, the Amazon Basin and South and Southeast Asia. For each region, diverse climate human-induced forcings and feedbacks were identified based on relevant published literature. For Europe, the positive soil moisture-evapotranspiration (ET) is important for natural vegetation during a heat wave event, while the positive soil moisture-precipitation feedback plays a more important role for droughts in the Amazon region. Agricultural expansion in SSA will depend on the impacts of the changing climate on crop yields and the adopted agro-technologies. The adoption of irrigation in the commonly rainfed systems might turn the positive soil moisture- ET feedback into a negative one. In contrast, South and Southeast Asia might face water shortage in the future, and thus turning the soil moisture-ET feedback into a positive one. Further research is needed for the major processes that affect the ultimate sign of the feedbacks, as well as for the interactions, which effect remains uncertain, such as ET-precipitation interaction. In addition, socio-economic feedbacks need to be added

Tumor heterogeneity and progression: conceptual foundations for modeling.

Science.gov (United States)

Greller, L D; Tobin, F L; Poste, G

1996-01-01

A conceptual foundation for modeling tumor progression, growth, and heterogeneity is presented. The purpose of such models is to aid understanding, test ideas, formulate experiments, and to model cancer 'in machina' to address the dynamic features of tumor cell heterogeneity, progression, and growth. The descriptive capabilities of such an approach provides a consistent language for qualitatively reasoning about tumor behavior. This approach provides a schema for building conceptual models that combine three key phenomenological driving elements: growth, progression, and genetic instability. The growth element encompasses processes contributing to changes in tumor bulk and is distinct from progression per se. The progression element subsumes a broad collection of processes underlying phenotypic progression. The genetics elements represents heritable changes which potentially affect tumor character and behavior. Models, conceptual and mathematical, can be built for different tumor situations by drawing upon the interaction of these three distinct driving elements. These models can be used as tools to explore a diversity of hypotheses concerning dynamic changes in cellular populations during tumor progression, including the generation of intratumor heterogeneity. Such models can also serve to guide experimentation and to gain insight into dynamic aspects of complex tumor behavior.

Climate Change and Conceptual Change

OpenAIRE

Clark, David Joseph

2013-01-01

Global Warming (“GW”) is easily one of the most pressing concerns of our time,and its solution will come about only through a change in human behavior.Compared to the residents of most other nations worldwide, Americans reportlower acceptance of the realities of GW. In order to address this concern in afree society, U.S. residents must be convinced or coerced to take the necessaryactions. In spite of the democratic appeal of education, however, many climatecommunicators appear t...

The Role of the Nurse in the Rehabilitation of Patients with Radical Changes in Body Image Due to Burn Injuries

OpenAIRE

Aacovou, I.

2005-01-01

Burn injuries are among the most serious causes of radical changes in body image. The subject of body image and self-image is essential in rehabilitation, and the nurse must be aware of the issues related to these concepts and take them seriously into account in drafting out the nursing programme. This paper defines certain key words related to body image and discusses the social context of body image. Burn injuries are considered in relation to the way each of these affects the patient's bod...

Interaction of radiation-generated radicals with myoglobin in aqueous solution

International Nuclear Information System (INIS)

Whitburn, K.D.; Hoffman, M.Z.

1985-01-01

The γ-radiolysis of aqueous solutions of ferrimyoglobin in the presence of N 2 O at pH 7.3 has been examined as a function of added catalase and oxygen. Changes in the nature of the heme group have been monitored by visible absorption spectrophotometry and analysed quantitatively by a multiple wavelength method based on Beer's Law. Simple chemical analyses have been used to confirm qualitative identification of the product derivatives. As observed previously, the ferriheme is reduced by indirect globin-mediated action initiated by radical OH/H radical. The yield of reduced product decreases as [O 2 ] derived from irradiated water and from protein-mediated processes in oxygenated solution, is eliminated by the presence of catalase. Formation of a hemichrome form of ferrimyoglobin is apparent at higher doses in the presence of O 2 . These results demonstrate that oxygen plays an important role in controlling the nature and extent of redox that manifests ultimately on the heme group of ferrimyoglobin as a result of the initial interaction of radical OH/H radical. (author)

Radical production in biological systems

International Nuclear Information System (INIS)

Johnson, J.R.; Akabani, G.

1994-10-01

This paper describes our effort to develop a metric for radiation exposure that is more fundamental than adsorbed dose and upon which a metric for exposure to chemicals could be based. This metric is based on the production of radicals by the two agents. Radicals produced by radiation in biological systems commonly assumed to be the same as those produced in water despite the presence of a variety of complex molecules. This may explain why the extensive efforts to describe the relationship between energy deposition (track structure) and molecular damage to DNA, based on the spectrum of radicals produced, have not been successful in explaining simple biological effects such as cell killing. Current models assume that DNA and its basic elements are immersed in water-like media and only model the production and diffusion of water-based radicals and their interaction with DNA structures; these models lack the cross sections associated with each macro-component of DNA and only treat water-based radicals. It has been found that such models are not realistic because DNA is not immersed in pure water. A computer code capable of simulating electron tracks, low-energy electrons, energy deposition in small molecules, and radical production and diffusion in water like media has been developed. This code is still in at a primitive stage and development is continuing. It is being used to study radical production by radiation, and radical diffusion and interactions in simple molecular systems following their production. We are extending the code to radical production by chemicals to complement our PBPK modeling efforts. It therefore has been developed primarily for use with radionuclides that are in biological materials, and not for radiation fields

Ion microbeam irradiation for radiobiology and radical chemistry: status and prospect

Energy Technology Data Exchange (ETDEWEB)

Khodja, H, E-mail: hicham.khodja@cea.fr [CEA, IRAMIS, SIS2M, LEEL, 91191 Gif-sur-Yvette (France); CNRS, UMR 3299, SIS2M, LEEL, 91191 Gif-sur-Yvette (France)

2011-01-01

Ion microbeams are commonly used to study local irradiation effects in living cells, as it has been established that ion beam irradiations can lead to deleterious changes in cells that are not struck directly by the microbeam. Such changes, which take place over distances long compared to the size of the irradiation spot and for times long compared to the time of irradiation, are collectively termed radiation-induced bystander effect or RIBE. Free-radical chemistry is frequently invoked to explain the RIBE but no unified model is available at present. Ion microbeams when coupled with advanced methods for observing free radicals are the tools of choice for investigating the chemistry and biological processes governing RIBE.

EFFECT OF CADMIUM(II) ON FREE RADICALS IN DOPA-MELANIN TESTED BY EPR SPECTROSCOPY.

Science.gov (United States)

Zdybel, Magdalena; Pilawa, Barbara; Chodurek, Ewa

2015-01-01

Electron paramagnetic resonance (EPR) spectroscopy may be applied to examine interactions of melanin with metal ions and drugs. In this work EPR method was used to examination of changes in free radical system of DOPA-melanin--the model eumelanin after complexing with diamagnetic cadmium(II) ions. Cadmium(II) may affect free radicals in melanin and drugs binding by this polymer, so the knowledge of modification of properties and free radical concentration in melanin is important to pharmacy. The effect of cadmium(II) in different concentrations on free radicals in DOPA-melanin was determined. EPR spectra of DOPA-melanin, and DOPA-melanin complexes with cadmium(II) were measured by an X-band (9.3 GHz) EPR spectrometer produced by Radiopan (Poznań, Poland) and the Rapid Scan Unit from Jagmar (Krak6w, Poland). The DOPA (3,4-dihydroxyphenylalanine) to metal ions molar ratios in the reaction mixtures were 2:1, 1:1, and 1: 2. High concentrations of o-semiquinone (g ~2.0040) free radicals (~10(21)-10(22) spin/g) characterize DOPA-melanin and its complexes with cadmium(II). Formation of melanin complexes with cadmium(II) increase free radical concentration in DOPA-melanin. The highest free radical concentration was obtained for DOPA-melanin-cadmium(II) (1:1) complexes. Broad EPR lines with linewidths: 0.37-0.73 mT, were measured. Linewidths increase after binding of cadmium(II) to melanin. Changes of integral intensities and linewidths with increasing microwave power indicate the homogeneous broadening of EPR lines, independently on the metal ion concentration. Slow spin-lattice relaxation processes existed in all the tested samples, their EPR lines saturated at low microwave powers. Cadmium(II) causes fastening of spin-lattice relaxation processes in DOPA-melanin. The EPR results bring to light the effect of cadmium(II) on free radicals in melanin, and probably as the consequence on drug binding to eumelanin.

Chemical repair of trypsin-histidinyl radical

International Nuclear Information System (INIS)

Jovanovic, S.V.; Ruvarac, I.; Jankovic, I.; Josimovic, L.

1991-01-01

Oxyl radicals, such as hydroxyl, alkoxyl and peroxyl, react with biomolecules to produce bioradicals. Unless chemically repaired by suitable antioxidants, these bioradicals form stable products. This leads to loss of biological function of parent biomolecules with deleterious biological results, such as mutagenesis and cancer. Consequently, the understanding of the mechanisms of oxyl radical damage to biomolecules and chemical repair of such damage is crucial for the development of strategies for anticarcinogenesis and radioprotection. In this study the chemical repair of the histidinyl radical generated upon the trichloromethylperoxyl radical reaction with trypsin vas investigated by gamma radiolysis. The trypsin histidinyl radical is a resonance-stabilized heterocyclic free radical which was found to be unreactive with oxygen. The efficacy of the chemical repair of the trypsin-histidinyl radical by endogenous antioxidants which are electron donors (e.g. 5-hydroxytryptophan, uric acid) is compared to that of antioxidants which are H-atom donors (e. g. glutathione). 9 refs., 2 figs., 1 tab

Electron paramagnetic resonance study of conformational effects in alkyl-substituted 2-cyclohexanonyl radicals in an adamantane matrix

International Nuclear Information System (INIS)

Walter, H.F.

1975-01-01

Electron paramagnetic resonance spectra have been obtained for radicals produced by x-irradiation of cyclohexanone and various alkyl-substituted cyclohexanones trapped in an adamantane matrix. Temperature variation of these spectra permits determination of the enthalpy and entropy of activation for interconversion between the two half-chair conformations. In those cases where the two conformations have intrinsically different energies, the enthalpy and entropy differences between conformations are determined. For 2-cyclohexanonyl radical, the enthalpy of activation is 3.90 +- 0.07 kcal/mole and the entropy of activation is -2.3 +- 0.3 e.u. Methyl substitution on C 3 or C 5 gives a radical with activation parameters similar to the parent radical, indicating moderate realignment of atoms during the conformational change. Methyl substitution on C 4 gives a radical with lower activation parameters, which are interpreted to indicate conformational change mainly be a folding along the diagonal through the radical site. Larger groups attached to C 3 influence enthalpy and entropy differences between conformations much less than when they are attached to C 5 . Very large groups attached to C 5 apparently flatten the ring; it is not known whether or not this is a matrix effect. Deuteration seems to cause a slight reduction in the activation parameters for 2-cyclohexanonyl radical

The picture superiority effect in conceptual implicit memory: a conceptual distinctiveness hypothesis.

Science.gov (United States)

Hamilton, Maryellen; Geraci, Lisa

2006-01-01

According to leading theories, the picture superiority effect is driven by conceptual processing, yet this effect has been difficult to obtain using conceptual implicit memory tests. We hypothesized that the picture superiority effect results from conceptual processing of a picture's distinctive features rather than a picture's semantic features. To test this hypothesis, we used 2 conceptual implicit general knowledge tests; one cued conceptually distinctive features (e.g., "What animal has large eyes?") and the other cued semantic features (e.g., "What animal is the figurehead of Tootsie Roll?"). Results showed a picture superiority effect only on the conceptual test using distinctive cues, supporting our hypothesis that this effect is mediated by conceptual processing of a picture's distinctive features.

Gnosticism and Radical Feminism

DEFF Research Database (Denmark)

Cahana, Jonathan

2016-01-01

and radical feminism would easily fall under this definition. There is, however, one major difference: since radical feminism is a relatively recent phenomenon which also benefited from modern modes of text production and preservation, almost all of the sources are still with us. This, in turn, may allow us...... to use radical feminism to make certain aspects of ancient Gnosticism re-emerge from their long submersion, provided that enough similarities can be independently drawn between the two phenomena to merit such a comparison. This paper therefore presents a comparison between concepts and positions...

Radical's view of sciences

International Nuclear Information System (INIS)

Mittal, J.P.

2004-01-01

Full text: General concept in radiation biology is that free radicals are highly reactive and they can damage vital cellular molecules leading to injurious effects. However, in this talk, evidence will be presented through the techniques of electron paramagnetic resonance ( EPR ) and pulse radiolysis that free radicals can be highly selective in their reaction with the target molecules. In addition, attempts will be made to present a brief account of emerging scenario of free radical generation, identification and their involvement in radiation damage mechanisms in chemical and biological systems

Generation of radicals in hard biological tissues under the action of laser radiation

Science.gov (United States)

Sviridov, Alexander P.; Bagratashvili, Victor N.; Sobol, Emil N.; Omelchenko, Alexander I.; Lunina, Elena V.; Zhitnev, Yurii N.; Markaryan, Galina L.; Lunin, Valerii V.

2002-07-01

The formation of radicals upon UV and IR laser irradiation of some biological tissues and their components was studied by the EPR technique. The radical decay kinetics in body tissue specimens after their irradiation with UV light were described by various models. By the spin trapping technique, it was shown that radicals were not produced during IR laser irradiation of cartilaginous tissue. A change in optical absorption spectra and the dynamics of optical density of cartilaginous tissue, fish scale, and a collagen film under exposure to laser radiation in an air, oxygen, and nitrogen atmosphere was studied.

Potential for free radical-induced lipid peroxidation as a cause of endothelial cell injury in Rocky Mountain spotted fever.

Science.gov (United States)

Silverman, D J; Santucci, L A

1988-01-01

Cells infected by Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, display unusual intracellular morphological changes characterized by dilatation of the membranes of the endoplasmic reticulum and outer nuclear envelope. These changes are consistent with those that might be expected to occur following peroxidation of membrane lipids initiated by oxygen radical species, such as the hydroxyl radical or a variety of organic radicals. Using a fluorescent probe, we have found significantly increased levels of peroxides in human endothelial cells infected by R. rickettsii. Studies with desferrioxamine, an iron chelator effective in preventing formation of the hydroxyl radical from hydrogen peroxide and the superoxide free radical, reduced peroxide levels in infected cells to those found in uninfected cells. This observation suggests that the increased peroxides in infected cells may be lipid peroxides, degradation products of free radical attack on polyenoic fatty acids. The potential for lipid peroxidation as an important mechanism in endothelial cell injury caused by R. rickettsii is discussed. Images PMID:3141280

WHAT DOES A WORD ALTER? THE EFFECT OF CONCEPTUAL NETWORKS ON THE DIMENSIONAL CHANGE SORTING TASK

Directory of Open Access Journals (Sweden)

Tolga Yildiz

2013-06-01

Full Text Available The purpose of the research was to examine the cognitive flexibility of three-year-olds, who usually persevere in the Dimensional Change Card Sort task, when a constant representation was referred in the classic instruction. In accordance with this purpose, the Dimensional Change Pencil Sort task was developed and used in the current study that 13 three-year-olds participated in. Findings seemed to support partially the hypothesis predicted that the kids could achieve the task in terms of rule use and mental representational flexibilities between length and color at the post switch phase in which situation classification dimensions were referred over a real and constant object (pencil instead of a card. This result drew attention to the conceptual and perceptual mediation roles of language and objects respectively in terms of the cognitive flexibility literature.

EPR spin trapping of protein radicals

DEFF Research Database (Denmark)

Davies, Michael Jonathan; Hawkins, Clare Louise

2004-01-01

Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress...... tumbling radicals are often broad and relatively poor in distinctive features, a number of techniques have been developed that allow a wealth of information to be obtained about the nature, site, and reactions of such radicals. This article summarizes recent developments in this area and reviews selected...... examples of radical formation on proteins....

Conceptual Frameworks for the Workplace Change Adoption Process: Elements Integration from Decision Making and Learning Cycle Process.

Science.gov (United States)

Radin Umar, Radin Zaid; Sommerich, Carolyn M; Lavender, Steve A; Sanders, Elizabeth; Evans, Kevin D

2018-05-14

Sound workplace ergonomics and safety-related interventions may be resisted by employees, and this may be detrimental to multiple stakeholders. Understanding fundamental aspects of decision making, behavioral change, and learning cycles may provide insights into pathways influencing employees' acceptance of interventions. This manuscript reviews published literature on thinking processes and other topics relevant to decision making and incorporates the findings into two new conceptual frameworks of the workplace change adoption process. Such frameworks are useful for thinking about adoption in different ways and testing changes to traditional intervention implementation processes. Moving forward, it is recommended that future research focuses on systematic exploration of implementation process activities that integrate principles from the research literature on sensemaking, decision making, and learning processes. Such exploration may provide the groundwork for development of specific implementation strategies that are theoretically grounded and provide a revised understanding of how successful intervention adoption processes work.

Remediation in Practicing Physicians: Current and Alternative Conceptualizations.

Science.gov (United States)

Bourgeois-Law, Gisèle; Teunissen, Pim W; Regehr, Glenn

2018-04-24

Suboptimal performance in practicing physicians is a decades-old problem. The lack of a universally accepted definition of remediation, the paucity of research on best remediation practices, and the ongoing controversy regarding the institutional responsibility for enacting and overseeing this activity suggests that the remediation of physicians is not merely a difficult problem to solve, but a problem that the community does not grapple with meaningfully. Undoubtedly, logistical and political considerations contribute to this state of affairs; however, other underlying conceptual issues may also play a role in the medical profession's difficulties in engaging with the challenges around remediation.Through a review of the medical education and other literatures, the authors examined current conceptualizations of both remediation itself and the individual being remediated, as well as how the culture of medicine influences these conceptions. The authors explored how conceptualizations of remediation and the surrounding culture might affect not only the medical community's ability to support, but also its willingness to engage with physicians in need of remediation.Viewing remediation as a means of supporting practice change-rather than as a means of redressing gaps in knowledge and skill-might be a useful alternative conceptualization, providing a good place to start exploring new avenues of research. However, moving forward will require more than simply a reconceptualizion of remediation; it will also necessitate a change in how the community views its struggling members and a change in the medical culture that currently positions professional autonomy as the foundational premise for individual practice improvement.

Fragmentation characteristics of the unstable [CH3 CO][radical sign] radicals generated by neutralization of [CH3CO]+ cations

Science.gov (United States)

Hop, C. E. C. A.; Holmes, J. L.

1991-03-01

The stability and fragmentation characteristics of [CH3 CO][radical sign] radicals, generated by vertical charge exchange between acetyl cations and permanent gases or metal vapours (He, Xe, NO, Cd, Na and K), were examined mass spectrometrically. Two dissociation reactions were observed, the losses of CH[radical sign]3 and H[radical sign]. The H[radical sign] loss reaction, the higher energy dissociation, became of greater importance as the exothermicity of the charge exchange was increased. Based on the analysis of the kinetic energy releases it was concluded that these decompositions arose from the population of two excited states of the [CH3 CO][radical sign] radical.

Metal-Diazo Radicals of α-Carbonyl Diazomethanes

Science.gov (United States)

Li, Feifei; Xiao, Longqiang; Liu, Lijian

2016-03-01

Metal-diazo radicals of α-carbonyl diazomethanes are new members of the radical family and are precursors to metal-carbene radicals. Herein, using electron paramagnetic resonance spectroscopy with spin-trapping, we detect diazo radicals of α-carbonyl diazomethanes, induced by [RhICl(cod)]2, [CoII(por)] and PdCl2, at room temperature. The unique quintet signal of the Rh-diazo radical was observed in measurements of α-carbonyl diazomethane adducts of [RhICl(cod)]2 in the presence of 5,5-dimethyl-pyrroline-1-N-oxide (DMPO). DFT calculations indicated that 97.2% of spin density is localized on the diazo moiety. Co- and Pd-diazo radicals are EPR silent but were captured by DMPO to form spin adducts of DMPO-N• (triplet-of-sextets signal). The spin-trapping also provides a powerful tool for detection of metal-carbene radicals, as evidenced by the DMPO-trapped carbene radicals (DMPO-C•, sextet signal) and 2-methyl-2-nitrosopropane-carbene adducts (MNP-C•, doublet-of-triplets signal). The transformation of α-carbonyl diazomethanes to metal-carbene radicals was confirmed to be a two-step process via metal-diazo radicals.

Conceptualizing In-service Secondary School Science Teachers' Knowledge Base for Promoting Understanding about the Science of Global Climate Change

Science.gov (United States)

Bhattacharya, Devarati

Efforts to adapt and mitigate the effects of global climate change (GCC) have been ongoing for the past two decades and have become a major global concern. However, research and practice for promoting climate literacy and understanding about GCC have only recently become a national priority. The National Research Council (NRC), has recently emphasized upon the importance of developing learners' capacity of reasoning, their argumentation skills and understanding of GCC (Framework for K-12 Science Education, National Research Council, 2012). This framework focuses on fostering conceptual clarity about GCC to promote innovation, resilience, and readiness in students as a response towards the threat of a changing environment. Previous research about teacher understanding of GCC describes that in spite of the prevalent frameworks like the AAAS Science Literacy Atlas (AAAS, 2007) and the Essential Principles for Climate Literacy (United States Global Climate Research Program, 2009; Bardsley, 2007), most learners are challenged in understanding the science of GCC (Michail et al., 2007) and misinformed perceptions about basic climate science content and the role of human activities in changing climate remain persistent (Reibich and Gautier, 2006). Our teacher participants had a rather simplistic knowledge structure. While aware of climate change, teacher participants lacked in depth understanding of how change in climate can impact various ecosystems on the Earth. Furthermore, they felt overwhelmed with the extensive amount of information needed to comprehend the complexity in GCC. Hence, extensive efforts not only focused on assessing conceptual understanding of GCC but also for teaching complex science topics like GCC are essential. This dissertation explains concept mapping, and the photo elicitation method for assessing teachers' understanding of GCC and the use of metacognitive scaffolding in instruction of GCC for developing competence of learners in this complex

Electron spin resonance study on γ-ray-induced radical species in ethylene hydrate

International Nuclear Information System (INIS)

Takeya, Kei; Sugahara, Takeshi; Ohgaki, Kazunari; Tani, Atsushi

2007-01-01

Electron spin resonance (ESR) study on γ-irradiated synthetic ethylene hydrate was performed to investigate induced radicals and their thermal stability. ESR spectra of induced 3-butenyl radical (.CH 2 C 2 H 3 =CH 2 ,g=2.0039±0.0005,A α =2.2±0.1mTandA β =3.0±0.1mT) and induced ethyl radical (.C 2 H 5 , g=2.0044±0.0005, A α =2.2±0.1mT and A β =2.7±0.1mT) were observed in irradiated ethylene hydrate. The decay of the 3-butenyl radicals was observed above 200 K with the activation energy of 51.9±4.4kJ/mol. The obvious decay of ethyl radicals starts above 240 K that is close to the dissociation temperature of ethylene hydrate at atmospheric pressure. The activation energy of the ethyl radical decay is estimated as 63.4±8.2kJ/mol and nearly equal to the enthalpy change of ethylene hydrate into liquid water and gaseous ethylene. It is suggested that the decay of ethyl radicals would be caused by the hydrate dissociation and that ethylene hydrate dissociates into water (supercooled) and ethylene at 240-265 K.

Reaction between protein radicals and other biomolecules

DEFF Research Database (Denmark)

Østdal, H.; Davies, M.J.; Andersen, Henrik Jørgen

2002-01-01

The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2....... Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid...

Radical intermediates involved in the bleaching of the carotenoid crocin. Hydroxyl radicals, superoxide anions and hydrated electrons

International Nuclear Information System (INIS)

Bors, W.; Saran, M.; Michel, C.

1982-01-01

The participation of the primary radicals in the bleaching of aqueous solutions of the carotenoid crocin by ionizing radiation was investigated, employing both X-radiolysis and pulse radiolysis. The pulse-radiolytic data demonstrated a very rapid diffusion-controlled attack by both hydroxyl radicals (radicalsOH) and hydrated electrons (e - sub(aq)), while superoxide anions (O 2 - ) did not react at all. The site of the initial reaction of these radicals was not limited to the polyene chromophore. Slower secondary reactions involving crocin alkyl or peroxy radicals contribute mainly to the overall bleaching, in particular during steady-state irradiation. (author)

Formation of long-lived radicals on proteins by radical transfer from heme enzymes--a common process?

DEFF Research Database (Denmark)

Ostdal, H; Andersen, H J; Davies, Michael Jonathan

1999-01-01

concentrations were observed after limited digestion, although this effect was less marked with the HRP/H2O2/BSA system than with Fe(III)Mb/H2O2/BSA, consistent with different modes of radical transfer. More extensive digestion of BSA decreased the radical concentration to levels below those detected with native...... investigated using horseradish peroxidase (HRP)/H2O2, in the presence and absence of added tyrosine. Incubation of HRP with H2O2 and bovine or human serum albumins, in the presence and absence of tyrosine, gave long-lived albumin-derived radicals as detected by EPR spectroscopy. Evidence has been obtained...... for these albumin radicals being located on buried tyrosine residues on the basis of blocking experiments. The effect of protein conformation on radical transfer has been investigated using partial proteolytic digestion prior to protein oxidation. With HRP/H2O2/BSA and Fe(III)Mb/H2O2/BSA increased radical...

Scoping the proximal and distal dimensions of climate change on health and wellbeing.

Science.gov (United States)

Morris, George Paterson; Reis, Stefan; Beck, Sheila Anne; Fleming, Lora Elderkin; Adger, William Neil; Benton, Timothy Guy; Depledge, Michael Harold

2017-12-05

The impacts of climate on health and wellbeing occur in time and space and through a range of indirect, complicated mechanisms. This diversity of pathways has major implications for national public health planning and influence on interventions that might help to mitigate and adapt to rapidly changing environmental conditions, nationally and internationally. This paper draws upon evidence from public health and adverse impact studies across climate science, hydrology, agriculture, public health, and the social sciences. It presents a conceptual model to support decision-making by recognizing both the proximal and distal pathways from climate-induced environmental change to national health and wellbeing. The proximal and distal pathways associated with food security, migration and mobility illustrate the diverse climate change influences in different geographic locations over different timescales. We argue that greater realization and articulation of proximal and distal pathways should radically alter how climate change is addressed as a national and international public health challenge.

Methodological Behaviorism from the Standpoint of a Radical Behaviorist.

Science.gov (United States)

Moore, J

2013-01-01

Methodological behaviorism is the name for a prescriptive orientation to psychological science. Its first and original feature is that the terms and concepts deployed in psychological theories and explanations should be based on observable stimuli and behavior. I argue that the interpretation of the phrase "based on" has changed over the years because of the influence of operationism. Its second feature, which developed after the first and is prominent in contemporary psychology, is that research should emphasize formal testing of a theory that involves mediating theoretical entities from an nonbehavioral dimension according to the hypothetico-deductive method. I argue that for contemporary methodological behaviorism, explanations of the behavior of both participants and scientists appeal to the mediating entities as mental causes, if only indirectly. In contrast to methodological behaviorism is the radical behaviorism of B. F. Skinner. Unlike methodological behaviorism, radical behaviorism conceives of verbal behavior in terms of an operant process that involves antecedent circumstances and reinforcing consequences, rather than in terms of a nonbehavioral process that involves reference and symbolism. In addition, radical behaviorism recognizes private behavioral events and subscribes to research and explanatory practices that do not include testing hypotheses about supposed mediating entities from another dimension. I conclude that methodological behaviorism is actually closer to mentalism than to Skinner's radical behaviorism.

Radical surgery compared with intracavitary cesium followed by radical surgery in cervical carcinoma stage IB

Energy Technology Data Exchange (ETDEWEB)

Tinga, D.J.; Bouma, J.; Aalders, J.G. (Dept. of Obstetrics and Gynaecology, State Univ. Hospital, Groningen (Netherlands)); Hollema, H. (Dept. of Pathology, State Univ. Hospital, Groningen (Netherlands))

1990-01-01

Forty-nine patients aged {le} 45 years, with cervical carcinoma stage IB ({le} 3 cm) were treated with either primary radical surgery (n = 26), or intracavitary irradiation followed by radical surgery (n = 23). With primary surgery, ovarian function had been preserved in 15 of the 25 patients, who were alive and well. Seven of the primary surgery patients were irradiated postoperatively and 2 others with a central recurrence were cured by irradiation. One other patient, who was not irradiated postoperatively, had an intestinal metastasis and died of the disease. If any of the adverse prognostic factors (as reported in the literature) had been considered as an indication for postoperative irradiation, 17 patients instead of 7 would have been irradiated after primary radical surgery. In the comparable group of 23 patients treated by intracavitary irradiation and radical surgery (and in 4 cases postoperative irradiation as well) there was no recurrence. There was no significant statistical difference between the treatment results in the cesium + surgery group and those who underwent primary radical surgery. Young patients with early cervical carcinoma without prognostic indicators for postoperative irradiation can benefit from primary radical surgery, because their ovarian function can be preserved. (authors).

Radical surgery compared with intracavitary cesium followed by radical surgery in cervical carcinoma stage IB

International Nuclear Information System (INIS)

Tinga, D.J.; Bouma, J.; Aalders, J.G.; Hollema, H.

1990-01-01

Forty-nine patients aged ≤ 45 years, with cervical carcinoma stage IB (≤ 3 cm) were treated with either primary radical surgery (n = 26), or intracavitary irradiation followed by radical surgery (n = 23). With primary surgery, ovarian function had been preserved in 15 of the 25 patients, who were alive and well. Seven of the primary surgery patients were irradiated postoperatively and 2 others with a central recurrence were cured by irradiation. One other patient, who was not irradiated postoperatively, had an intestinal metastasis and died of the disease. If any of the adverse prognostic factors (as reported in the literature) had been considered as an indication for postoperative irradiation, 17 patients instead of 7 would have been irradiated after primary radical surgery. In the comparable group of 23 patients treated by intracavitary irradiation and radical surgery (and in 4 cases postoperative irradiation as well) there was no recurrence. There was no significant statistical difference between the treatment results in the cesium + surgery group and those who underwent primary radical surgery. Young patients with early cervical carcinoma without prognostic indicators for postoperative irradiation can benefit from primary radical surgery, because their ovarian function can be preserved. (authors)

Co-evolution of hydrological components under climate change scenarios in the Mediterranean area

Energy Technology Data Exchange (ETDEWEB)

Viola, F., E-mail: francesco.viola77@unipa.it; Francipane, A.; Caracciolo, D.; Pumo, D.; La Loggia, G.; Noto, L.V.

2016-02-15

ABSTRACT: The Mediterranean area is historically characterized by high human pressure on water resources. Today, while climate is projected to be modified in the future, through precipitation decrease and temperature increase, that jointly and non-linearly may affect runoff, concerns about water availability are increasing. For these reasons, quantitative assessment of future modifications in the mean annual water availability are important; likewise, the description of the future interannual variability of some hydrological components such as runoff and evapotranspiration are highly wished for water management and ecosystems dynamics analyses. This study investigates at basin spatial scale future runoff and evapotranspiration, exploring their probability density functions and their interdependence as functions of climatic changes. In order to do that, a parsimonious conceptual lumped model is here used. The model is forced by different future climate scenarios, generated through a weather generator based on a stochastic downscaling of an ensemble of General Circulation Models (GCMs) realizations. The use of the adopted hydrological model, under reliable stochastic future climate scenarios, allows to project future values of evapotranspiration and runoff in a probabilistic framework and, at the same time, the evaluation of their bivariate frequency distributions for changes through the Multivariate Kernel Density Estimation method. As a case study, a benchmark Mediterranean watershed has been proposed (Imera Meridionale, Italy). Results suggest a radical shift and shape modification of the annual runoff and evapotranspiration probability density functions. Possible implications and impacts on water resources management are here addressed and discussed. - Highlights: • This study investigates at basin spatial scale future runoff and evapotranspiration. • A simple conceptual hydrological model and GCMs realizations have been coupled. • Radical shift and shape

Co-evolution of hydrological components under climate change scenarios in the Mediterranean area

International Nuclear Information System (INIS)

Viola, F.; Francipane, A.; Caracciolo, D.; Pumo, D.; La Loggia, G.; Noto, L.V.

2016-01-01

ABSTRACT: The Mediterranean area is historically characterized by high human pressure on water resources. Today, while climate is projected to be modified in the future, through precipitation decrease and temperature increase, that jointly and non-linearly may affect runoff, concerns about water availability are increasing. For these reasons, quantitative assessment of future modifications in the mean annual water availability are important; likewise, the description of the future interannual variability of some hydrological components such as runoff and evapotranspiration are highly wished for water management and ecosystems dynamics analyses. This study investigates at basin spatial scale future runoff and evapotranspiration, exploring their probability density functions and their interdependence as functions of climatic changes. In order to do that, a parsimonious conceptual lumped model is here used. The model is forced by different future climate scenarios, generated through a weather generator based on a stochastic downscaling of an ensemble of General Circulation Models (GCMs) realizations. The use of the adopted hydrological model, under reliable stochastic future climate scenarios, allows to project future values of evapotranspiration and runoff in a probabilistic framework and, at the same time, the evaluation of their bivariate frequency distributions for changes through the Multivariate Kernel Density Estimation method. As a case study, a benchmark Mediterranean watershed has been proposed (Imera Meridionale, Italy). Results suggest a radical shift and shape modification of the annual runoff and evapotranspiration probability density functions. Possible implications and impacts on water resources management are here addressed and discussed. - Highlights: • This study investigates at basin spatial scale future runoff and evapotranspiration. • A simple conceptual hydrological model and GCMs realizations have been coupled. • Radical shift and shape

Free radicals in an Adamantane matrix. XI. Electron paramagnetic resonance study of conformations in the β-halo-tert-butyl radicals

International Nuclear Information System (INIS)

Lloyd, R.V.; Wood, D.E.

1975-01-01

The β-halo-tert-butyl radicals were prepared by x-irradiation of the corresponding isobutyl halides in an adamantane matrix at 77 0 K and their conformations were determined by analysis of their EPR spectra. The radicals are nonplanar at the radical site, the fluoro and chloro radicals trans eclipsed and the bromo and iodo radicals gauche staggered with respect to the relative orientation of the carbon halogen bond and the direction of the singly occupied orbital. Vibration-rotation motions about the favored conformation are much larger for the fluoro radical than for the others. The rate of interconversion of the inequivalent methylene protons is approximately 1.5 x 10 9 sec -1 for the bromo radical at 202 0 K while it is too slow to measure for the iodo radical at the same temperature. The barrier to interconversion has a lower limit of 3 kcal/mol for the bromo radical and higher than that for the iodo radical. The halogen and proton hfsc in gauss and the g values for the XCH 2 C(CH 3 ) 2 radicals are: 19 F = 103.7, CH 2 = 10.4, CH 3 = 23.3, g = 2.0030 at 214 K; 35 Cl = 19.5, CH 2 = 6.3, CH 3 = 21.1, g = 2.0042 at 215 K; 81 Br = 6.7, CH 2 = 21.4, 42.7, CH 3 = 21.4, g = 2.0010 at 202 K; 127 I = 7.0, CH 2 = 21.9, 43.8, CH 3 = 21.9, g = 2.0009 at 208 K. The fluoro radical decays to nonradical products above 318 0 K, the chloro radical converts to 2-methyl allyl radical above 306 0 K, the bromo radical converts to tert-butyl radical by exchange with a matrix proton (or deuteron) at 209 0 K as does the iodo radical above 225 0 K. Photolysis with a Xe lamp converts the bromo and iodo radicals to nonradical products in less than the experimental time constant of 0.3 sec. The hypothesis is put forward that the nonplanarity and high barrier to rotation observed explain the retention of stereochemical configuration in reactions involving β-chloro, β-bromo, and β-iodo alkyl radicals. (auth)

17.9.3 Radical cations of diazo compounds

Science.gov (United States)

Davies, A. G.

This document is part of Subvolume E2 `Phosphorus-Centered Radicals, Radicals Centered on Other Heteroatoms, Organic Radical Ions' of Volume 26 `Magnetic Properties of Free Radicals' of Landolt-Börnstein Group II `Molecules and Radicals'.

The effect of near-infrared MLS laser radiation on cell membrane structure and radical generation.

Science.gov (United States)

Kujawa, Jolanta; Pasternak, Kamila; Zavodnik, Ilya; Irzmański, Robert; Wróbel, Dominika; Bryszewska, Maria

2014-09-01

The therapeutic effects of low-power laser radiation of different wavelengths and light doses are well known, but the biochemical mechanism of the interaction of laser light with living cells is not fully understood. We have investigated the effect of MLS (Multiwave Locked System) laser near-infrared irradiation on cell membrane structure, functional properties, and free radical generation using human red blood cells and breast cancer MCF-4 cells. The cells were irradiated with low-intensity MLS near-infrared (simultaneously 808 nm, continuous emission and 905 nm, pulse emission, pulse-wave frequency, 1,000 or 2,000 Hz) laser light at light doses from 0 to 15 J (average power density 212.5 mW/cm(2), spot size was 3.18 cm(2)) at 22 °C, the activity membrane bound acetylcholinesterase, cell stability, anti-oxidative activity, and free radical generation were the parameters used in characterizing the structural and functional changes of the cell. Near-infrared low-intensity laser radiation changed the acetylcholinesterase activity of the red blood cell membrane in a dose-dependent manner: There was a considerable increase of maximal enzymatic rate and Michaelis constant due to changes in the membrane structure. Integral parameters such as erythrocyte stability, membrane lipid peroxidation, or methemoglobin levels remained unchanged. Anti-oxidative capacity of the red blood cells increased after MLS laser irradiation. This irradiation induced a time-dependent increase in free radical generation in MCF-4 cells. Low-intensity near-infrared MLS laser radiation induces free radical generation and changes enzymatic and anti-oxidative activities of cellular components. Free radical generation may be the mechanism of the biomodulative effect of laser radiation.

Inhibition of radiation-induced DNA strand breaks by hoechst 33258: OH-radical scavenging and DNA radical quenching

International Nuclear Information System (INIS)

Adhikary, A.; Bothe, E.; Von Sonntag, C.; Adhikary, A.

1997-01-01

The minor-groove-binding dye Hoechst 33258 has been found to protect pBR322 DNA in aqueous solution against radiation-induced single-strand breaks (ssb). This protective effect has been assumed to be largely due to the scavenging of the strand-break-generating OH radicals by Hoechst. From D 37 values for ssb at different Hoechst concentrations the value of the OH radical scavenging constant of DNA-bound Hoechst has been estimated at k Ho/DNA = 2.7 * 10 11 dm 3 mol -1 . This unexpectedly high value has led us to study the reactions of OH radicals with Hoechst in the absence and in the presence of double-stranded calf thymus DNA (ds DNA) by pulse radiolysis, and the formation of radiation-induced ssb by low angle laser light scattering. The D 37 /D 37 0 values at different Hoechst concentrations agree with the values obtained by Martin and al. and demonstrate the protection. However, this protection cannot be explained on the basis of OH radical scavenging alone using the above rate constants. There must, in addition, be some quenching of DNA radicals. Hoechst radicals are formed in the later ms time range, i.e a long time after the disappearance of the OH radicals. This delayed Hoechst radical formation has been assigned to a a reaction of DNA radicals with Hoechst, thereby inhibiting strand breakage. In confirmation, pulse radiolysis of aqueous solution of nucleotides in the presence of Hoechst yields a similar delayed Hoechst radical formation. The data indicate that in DNA the cross-section of this quenching has a diameter of 3 to 4 base pairs per Hoechst molecule. (N.C.)

Radical-Local Teaching and Learning

DEFF Research Database (Denmark)

Hedegaard, Mariane; Chaiklin, Seth

Radical-Local Teaching and Learning presents a theoretical perspective for analyzing and planning educational programmes for schoolchildren. To realize both general societal interests and worthwhile personal development, the content of educational programmes for children must be grounded in the l......Radical-Local Teaching and Learning presents a theoretical perspective for analyzing and planning educational programmes for schoolchildren. To realize both general societal interests and worthwhile personal development, the content of educational programmes for children must be grounded...... radical-local teaching and learning approach. The first half of the book introduces the idea of radical-local teaching and learning and develops the theoretical background for this perspective, drawing on the cultural-historical research tradition, particularly from Vygotsky, El'konin, Davydov......, and Aidarova. The second half of the book addresses the central concern of radical-local teaching and learning - how to relate educational practices to children's specific historical and cultural conditions. The experiment was conducted for an academic year in an afterschool programme in the East Harlem...

Electronic structure of Co islands grown on the {radical}3 x {radical}3-Ag/Ge(111) surface

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiao-Lan; Chou, Chi-Hao; Lin, Chun-Liang; Tomaszewska, Agnieszka; Fu, Tsu-Yi, E-mail: phtifu@phy.ntnu.edu.tw

2011-09-30

By means of room temperature scanning tunneling spectroscopy (RT STS), we have studied the electronic structure of two different Ag/Ge(111) phases as well as Co islands grown on the {radical}3 x {radical}3-Ag/Ge (111) forming either {radical}13 x {radical}13 or 2 x 2 patterns. The spectrum obtained from 4 x 4-Ag/Ge(111) structure shows the existence of a shoulder at 0.7 V which is also present in the electronic structure of the Ge(111)-c2 x 8 and indicates donation of Ge electrons to electronic states of the Ag-driven phase. However, this fact is not supported by the electronic spectrum taken from the {radical}3 x {radical}3-Ag/Ge (111). The complexity of the Co-{radical}13 x {radical}13 islands bonding with the substrate is mirrored by a large number of peaks in their electronic spectra. The spectra obtained from the Co-2 x 2 islands which had grown on the step differ from those taken from Co-2 x 2 islands located along the edge of the terrace by a number of peaks at negative sample bias. This discrepancy is elucidated in terms of dissimilarities of Co-substrate interaction accompanying Co islands growth on different areas of the stepped surface.

Understanding political radicalization: The two-pyramids model.

Science.gov (United States)

McCauley, Clark; Moskalenko, Sophia

2017-04-01

This article reviews some of the milestones of thinking about political radicalization, as scholars and security officials struggled after 9/11 to discern the precursors of terrorist violence. Recent criticism of the concept of radicalization has been recognized, leading to a 2-pyramids model that responds to the criticism by separating radicalization of opinion from radicalization of action. Security and research implications of the 2-pyramids model are briefly described, ending with a call for more attention to emotional experience in understanding both radicalization of opinion and radicalization of action. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Orgasm after radical prostatectomy

NARCIS (Netherlands)

Koeman, M; VanDriel, MF; Schultz, WCMW; Mensink, HJA

Objective To evaluate the ability to obtain and the quality of orgasm after radical prostatectomy, Patients and methods The orgasms experienced after undergoing radical prostatectomy were evaluated in 20 men (median age 65 years, range 56-76) using a semi-structured interview and a self-administered

O Behaviorismo Radical como filosofia da mente Radical Behaviorism as philosophy of mind

Directory of Open Access Journals (Sweden)

Carlos Eduardo Lopes

2003-01-01

Full Text Available O Behaviorismo Radical de B. F. Skinner é constantemente acusado de eliminar a mente de sua explicação do comportamento humano. Uma análise do livro The Concept of Mind, de Gilbert Ryle, sugere a possibilidade de defender a existência de uma mente relacional, diferente da categoria de existência da mente defendida em interpretações cartesianas (mente substancial. A análise de alguns textos de Skinner sugere que o conceito de uma mente relacional também pode ser defendido no Behaviorismo Radical. Esse fato, culminaria na possibilidade de que, além de filosofia da Ciência do Comportamento, o Behaviorismo Radical, também pode ser uma filosofia da mente, o que traria conseqüências ao estudo e à aplicação da Análise do Comportamento.B. F. Skinner's Radical Behaviorism has been repeatedly accused of eliminating the mind from its explanation of human behavior. An analysis of Gilbert Ryle's book, The Concept of Mind, suggests the possibility of defending the existence of a relational mind, different from the category of existence of mind defended in Cartesian interpretations (substantial mind. The analysis of some texts of Skinner suggests that the concept of a relational mind can also be defended in Radical Behaviorism. This fact would lead to the possibility that, beyond a philosophy of Behavior Science, Radical Behaviorism may also be a philosophy of mind, which would bring consequences to the study and application of Analysis of Behavior.

Analysis of Subjective Conceptualizations Towards Collective Conceptual Modelling

DEFF Research Database (Denmark)

Glückstad, Fumiko Kano; Herlau, Tue; Schmidt, Mikkel Nørgaard

2013-01-01

This work is conducted as a preliminary study for a project where individuals' conceptualizations of domain knowledge will thoroughly be analyzed across 150 subjects from 6 countries. The project aims at investigating how humans' conceptualizations differ according to different types of mother la...

Muonium radicals in benzene-styrene mixtures

International Nuclear Information System (INIS)

Ng, B.W.; Stadlbauer, J.W.; Walker, D.C.

1984-01-01

Muonium radicals were observed through their μ + SR precession frequencies in high transverse magnetic fields in pure benzene, pure styrene and their mixtures, all as liquids at room temperature. In benzene-styrene mixtures, the radicals obtained in each pure liquid are both present, so no slow (10 -9 -10 -5 s) intermolecular exchange occurs; but strong selectivity was found with the formation of the radical from styrene being about eight-times more probable than the radical from benzene. (Auth.)

Radical Orthodoxy - Its ecumenical vision | Ward | Acta Theologica

African Journals Online (AJOL)

The first book in the Series Radical Orthodoxy (RO) was not meant to be programmatic or set out to change the direction of modern theology. There are certain shared sensibilities among its authors and, principally, an ecumenical vision. This article sketches the nature of that ecumenical vision that begins with the way in ...

A Conceptual Space Logic

DEFF Research Database (Denmark)

Nilsson, Jørgen Fischer

1999-01-01

Conceptual spaces have been proposed as topological or geometric means for establishing conceptual structures and models. This paper, after briey reviewing conceptual spaces, focusses on the relationship between conceptual spaces and logical concept languages with operations for combining concepts...... to form concepts. Speci cally is introduced an algebraic concept logic, for which conceptual spaces are installed as semantic domain as replacement for, or enrichment of, the traditional....

Laparoscopic radical cystectomy: key points

Directory of Open Access Journals (Sweden)

D. V. Perlin

2018-01-01

Full Text Available Background. Radical cystectomy remains the golden standard for treatment of muscle invasive bladder cancer. Objective: to duplicate with highest accuracy the open radical cystectomy procedure, which we successfully utilized earlier in our clinic, in the of laparoscopic conditions in order to preserve the advantages of minimally invasive procedures and retain the reliability of the tried and tested open surgery.Materials and methods. In the report were included 35 patients (27 men and 8 women with bladder cancer, who underwent laparoscopic radical cystectomy in Volgograd Regional Center of Urology and Nephrology between April 2013 and March 2016. Only the patients who had been submitted to full intracorporal ileal conduits were included.Results. The mean operative time was 378 minutes, the mean blood loss was 285 millilitres, the mean length of hospital stay was 12.4 days, only 20 % of patients required the narcotic anesthetics. The postoperative complication rate was 11.4 %. However, the majority of the patients were successfully treated with minimally invasive procedures. Generally, our results were similar to other reported studies.Conclusion. Laparoscopic radical cystectomy is a safe and efficient modality of treatment of bladder cancer. However, it needs more procedures and longer observation period to establish laparoscopic radical cystectomy as an alternative to open radical cystectomy.

My Science Is Better than Your Science: Conceptual Change as a Goal in Teaching Science Majors Interested in Teaching Careers about Education

Science.gov (United States)

Utter, Brian C.; Paulson, Scott A.; Almarode, John T.; Daniel, David B.

2018-01-01

We argue, based on a multi-year collaboration to develop a pedagogy course for physics majors by experts in physics, education, and the science of learning, that the process of teaching science majors about education and the science of learning, and evidence-based teaching methods in particular, requires conceptual change analogous to that…

The Effect of the Conceptual Change Oriented Instruction through Cooperative Learning on 4th Grade Students' Understanding of Earth and Sky Concepts

Science.gov (United States)

Celikten, Oksan; Ipekcioglu, Sevgi; Ertepinar, Hamide; Geban, Omer

2012-01-01

The purpose of this study was to compare the effectiveness of the conceptual change oriented instruction through cooperative learning (CCICL) and traditional science instruction (TI) on 4th grade students' understanding of earth and sky concepts and their attitudes toward earth and sky concepts. In this study, 56 fourth grade students from the…

Effects of Molecular Iodine and 4-tert-Butylcatechol Radical Inhibitor on the Radical Polymerization of Styrene

Directory of Open Access Journals (Sweden)

Mojtaba Bozorg

2017-05-01

Full Text Available The presence of molecular iodine was studied in relation the molecular weight and molecular weight distribution of polystyrene, produced by radical poly merization. Radical polymerization of styrene initiated by 2,2׳-azobisisobutyronitrile (AIBN was performed at 70°C in the presence of molecular iodine. The synthesized polymers were characterized by gel permeation chromatography (GPC and proton- nuclear magnetic resonance (1H NMR techniques. The results of these reactions including conversion data, number-average molecular weight and molecular weight distribution were compared with those obtained for styrene radical polymerization initiated by AIBN at the same temperature in the absence of molecular iodine. It was found that the presence of iodine had a profound effect on the molecular weight and its distribution in the produced polystyrene. This was attributed to the ability of iodine to control the polymerization of styrene initiated by AIBN via reverse iodine transfer polymerization (RITP mechanism. The polymer produced by this method had a molecular weight of 10600 g/mol with a molecular weight polydispersity index of 1.3. Due to the importance of induction period in reverse iodine transfer radical polymerization, increasing the temperature to 120°C during the induction period resulted in shorter induction periods and the produced species led to better control of the molecular weight. Also, due to the role of iodine molecules as a radical inhibitor, the presence of a secondary radical inhibitor, i.e. 4-tert-butylcatechol, along with the iodine was investigated in radical polymerization of polystyrene initiated by AIBN. It was observed that the secondary radical inhibitor prevented the consumption of the iodine molecules by the radicals produced from decomposition of the AIBN initiator; therefore, alkyl halides were not produced during the induction period.

[Concomitant oncopathological changes in the prostate of urinary bladder cancer patients undergoing radical cystoprostateectomy].

Science.gov (United States)

Komyakov, B K; Sergeev, A V; Fadeev, V A; Ismailov, K I; Ulyanov, A Yu; Shmelev, A Yu; Onoshko, M V

2017-09-01

To determine the incidence of spreading bladder transitional cell carcinoma and primary adenocarcinoma to the prostate in patients with bladder cancer undergoing radical cystectomy. From 1995 to 2016, 283 men underwent radical cystectomy with removal of the bladder, perivesical tissue, prostate, seminal vesicles and pelvic lymph nodes. Prostate sparing cystectomy was performed in 45 (13.7%) patients. The whole prostate and the apex of the prostate were preserved in 21 (6.4%) and 24 (7.3%) patients, respectively. The spread of transitional cell cancer of the bladder to the prostate occurred in 50 (15.2%) patients. Twelve (3.6%) patients were found to have primary prostate adenocarcinoma. Clinically significant prostate cancer was diagnosed in 4 (33.3%) patients. We believe that the high oncological risk of prostate sparing cystectomy, despite some functional advantages, dictates the need for complete removal of the prostate in the surgical treatment of bladder cancer.

Radical chemistry of artemisinin

Energy Technology Data Exchange (ETDEWEB)

Denisov, Evgenii T; Solodova, S L; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

2011-12-29

The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

Radical chemistry of artemisinin

Science.gov (United States)

Denisov, Evgenii T.; Solodova, S. L.; Denisova, Taisa G.

2010-12-01

The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

Radical chemistry of artemisinin

International Nuclear Information System (INIS)

Denisov, Evgenii T; Solodova, S L; Denisova, Taisa G

2010-01-01

The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

Radical chemistry of artemisinin

Energy Technology Data Exchange (ETDEWEB)

Denisov, Evgenii T; Solodova, S L; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

2010-12-29

The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

Oxygen free radicals in rheumatoid arthritis

NARCIS (Netherlands)

P. Biemond (Pieter)

1986-01-01

textabstractCurrent knowledge strongly suggests that oxygen free radicals are involved in the pathogenesis of RA. Additional information about the mechanism of free radical attack is necessary in order to find out if interaction with the mechanism of free radical damage can be used in the treatment

Free radicals in health and disease

International Nuclear Information System (INIS)

Gonet, B.

1993-01-01

Free radicals appear in the cells as the result of exogenic factors (ionizing radiation, UV) or reactions naturally occurring in the cell. Free radical reactions may cause destruction of macromolecules (DNA, lipids, proteins). Free radical pathology is important in many diseases and aging processes in organisms

Free radicals in wood induced by γ-radiation

International Nuclear Information System (INIS)

Xu Honglin; Zhang Wenhui

1994-01-01

The free radicals in wood induced by γ-radiation were studied by electron spin resonance. The fine structure of the ESR signal from sawdust samples irradiated could be resolved into various radicals. These free radicals have a very long lifetime. The major spectrum for the free radicals will exponentially increased along with the radiation dose according to Y 1-Exp(-α a D). The intensity of radiation radicals is dependent on tree species. The stronger the intensity of mechanic free radicals is, the stronger the intensity of radiation free radicals

Investigating students' conceptual change about colour in an innovative research-based teaching sequence

Directory of Open Access Journals (Sweden)

Ana Rita Lopes Mota

2018-04-01

Full Text Available This paper is the second part of a multiphase study investigating the impact of a mathematical model, the Addition Table of Colours (ATC, in the learning of colour phenomena. The ATC instruction was undertaken in several 8th grade classes in three different Portuguese schools (250 students and included collaborative activities through Lab stations model. In the control group (204 students, the colour phenomena were taught in the traditional way, with the goals set by the teachers, without any intervention of the project. The two groups of students were compared in terms of content knowledge acquired in the learning of this subject through comparison and analysis of their pre and post-tests. Quantitative analyses of the pre/post-tests revealed five variants of students’ representations about this phenomenon. We found that the ATC model, inserted in an interactive and carefully designed teaching environment, is more effective in promoting conceptual change and scientific understandings of colour phenomena.

Radical-Local Teaching and Learning

DEFF Research Database (Denmark)

Hedegaard, Mariane; Chaiklin, Seth

radical-local teaching and learning approach. The first half of the book introduces the idea of radical-local teaching and learning and develops the theoretical background for this perspective, drawing on the cultural-historical research tradition, particularly from Vygotsky, El'konin, Davydov......, and Aidarova. The second half of the book addresses the central concern of radical-local teaching and learning - how to relate educational practices to children's specific historical and cultural conditions. The experiment was conducted for an academic year in an afterschool programme in the East Harlem......Radical-Local Teaching and Learning presents a theoretical perspective for analyzing and planning educational programmes for schoolchildren. To realize both general societal interests and worthwhile personal development, the content of educational programmes for children must be grounded...

Conceptualizing Programme Evaluation

Science.gov (United States)

Hassan, Salochana

2013-01-01

The main thrust of this paper deals with the conceptualization of theory-driven evaluation pertaining to a tutor training programme. Conceptualization of evaluation, in this case, is an integration between a conceptualization model as well as a theoretical framework in the form of activity theory. Existing examples of frameworks of programme…

The Conceptual Framework of Thematic Mapping in Case Conceptualization.

Science.gov (United States)

Ridley, Charles R; Jeffrey, Christina E

2017-04-01

This article, the 3rd in a series of 5, introduces the conceptual framework for thematic mapping, a novel approach to case conceptualization. The framework is transtheoretical in that it is not constrained by the tenets or concepts of any one therapeutic orientation and transdiagnostic in that it conceptualizes clients outside the constraints of diagnostic criteria. Thematic mapping comprises 4 components: a definition, foundational principles, defining features, and core concepts. These components of the framework, deemed building blocks, are explained in this article. Like the foundation of any structure, the heuristic value of the method requires that the building blocks have integrity, coherence, and sound anchoring. We assert that the conceptual framework provides a solid foundation, making thematic mapping a potential asset in mental health treatment. © 2017 Wiley Periodicals, Inc.

A study of primary school teachers’ conceptual understanding on states of matter and their changes based on their job locations (case study at Ambon island in Moluccas-Indonesia)

Science.gov (United States)

Banawi, A.; Sopandi, W.; Kadarohman, A.; Solehuddin, M.

2018-05-01

The research aims to describe primary school teachers’ conceptual understandings about states of matter and their changes. The method was descriptive which involved 15 primary school teachers from three different school locations. They were from urban school (CS1), sub-urban school (CS2), and rular school (CS3) at Ambon Island on 2016/2017 academic year. The research instrument was a multiple-choice test combined with both essay and confidence level of their answers. The test was used to measure teachers’ understanding levels about states of matter and their changes. They were macroscopic, sub-microscopic and symbolic levels. Teachers’ understanding levels were classified into following categorization, they were understand, partly understand, misconception, and do not understand. The results show that primary school teachers’ conceptual understanding is varied based on their job locations and primary school teachers’ level understanding. Generally, primary school teachers’ conceptual understandings at sub-urban location (CS2) are better than those of both of urban (CS1) and rular locations (CS3). The results suggest that teachers need improvement to make better primary school teachers’ conceptual understanding. It can be on the job training and in service training activities. We also need a further research in order to investigate the program effectiveness.

Orthographic Skills Important to Chinese Literacy Development: The Role of Radical Representation and Orthographic Memory of Radicals

Science.gov (United States)

Yeung, Pui-sze; Ho, Connie Suk-han; Chan, David Wai-ock; Chung, Kevin Kien-hoa

2016-01-01

A 3-year longitudinal study among 239 Chinese students in Grades 2-4 was conducted to investigate the relationships between orthographic skills (including positional and functional knowledge of semantic radicals and phonetic radicals, and orthographic memory of radicals) and Chinese literacy skills (word reading, word spelling, reading…

The Games Radicals Play: Special Issue on Free Radicals and Radical Ions

Directory of Open Access Journals (Sweden)

John C. Walton

2015-02-01

Full Text Available Chemistry and Physics have aptly been described as “most excellent children of Intellect and Art” [1]. Both these “children” engage with many playthings, and molecules rank as one of their first favorites, especially radicals, which are amongst the most lively and exciting. Checking out radicals dancing to the music of entropy round their potential energy ballrooms is surely both entertaining and enlightening. Radicals’ old favorite convolutions are noteworthy, but the new styles, modes and arrangements appearing on the scene are even more interesting. Some of these are ephemeral and enjoy only a brief appearance, others are retro-types reappearing in new guises, still others are genuinely new and “go viral” in the scientific world. This Special Issue of Molecules contains the observations and reflections of a select group of chemists and physicists fascinated by this spectacle. It contains an eclectic mix reflecting on new modes and advances as well as on permutations and combinations that revive mature themes. [...

Voting for the populist radical right in Switzerland: A panel data analysis

OpenAIRE

Orsholits, Dan

2017-01-01

Working-class voters no longer systematically support left-wing political parties. This finding was initially viewed as signalling the end of class voting and the decline of the class cleavage's salience. Yet, in Western Europe, it would seem to be turning to a new party family: the populist radical right. This realignment is thought to be linked to globalization and the societal and economic changes that it brings. Populist radical right parties are thought to channel the frustrations of wor...

Radically enhanced molecular recognition

KAUST Repository

Trabolsi, Ali

2009-12-17

The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

Radically enhanced molecular recognition

KAUST Repository

Trabolsi, Ali; Khashab, Niveen M.; Fahrenbach, Albert C.; Friedman, Douglas C.; Colvin, Michael T.; Coti, Karla K.; Bení tez, Diego S.; Tkatchouk, Ekaterina; Olsen, John Carl; Belowich, Matthew E.; Carmieli, Raanan; Khatib, Hussam A.; Goddard, William Andrew III; Wasielewski, Michael R.; Stoddart, Fraser Fraser Raser

2009-01-01

The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

Using the Biology Card Sorting Task to Measure Changes in Conceptual Expertise during Postsecondary Biology Education

Science.gov (United States)

Bissonnette, Sarah A.; Combs, Elijah D.; Nagami, Paul H.; Byers, Victor; Fernandez, Juliana; Le, Dinh; Realin, Jared; Woodham, Selina; Smith, Julia I.; Tanner, Kimberly D.

2017-01-01

While there have been concerted efforts to reform undergraduate biology toward teaching students to organize their conceptual knowledge like experts, there are few tools that attempt to measure this. We previously developed the Biology Card Sorting Task (BCST), designed to probe how individuals organize their conceptual biological knowledge.…

Formation and spectroscopy of {alpha}-muoniated radicals

Energy Technology Data Exchange (ETDEWEB)

McKenzie, I.; Brodovitch, J.C.; Ghandi, K.; Kecman, S.; Percival, P.W

2003-02-01

Several novel {alpha}-muoniated radicals have been produced by the reaction of muonium with compounds containing diazo, isocyanate or carbene functional groups. In {alpha}-muoniated radicals the muon is attached directly to the radical centre; they can be formed either directly or indirectly via a {beta}-muoniated radical intermediate. The hyperfine coupling constants of the resulting radicals have been measured by transverse field muon spin rotation and muon avoided level-crossing resonance. The effect of muonium substitution was investigated for cases where ESR data are available for comparison.

Formation and spectroscopy of α-muoniated radicals

International Nuclear Information System (INIS)

McKenzie, I.; Brodovitch, J.C.; Ghandi, K.; Kecman, S.; Percival, P.W.

2003-01-01

Several novel α-muoniated radicals have been produced by the reaction of muonium with compounds containing diazo, isocyanate or carbene functional groups. In α-muoniated radicals the muon is attached directly to the radical centre; they can be formed either directly or indirectly via a β-muoniated radical intermediate. The hyperfine coupling constants of the resulting radicals have been measured by transverse field muon spin rotation and muon avoided level-crossing resonance. The effect of muonium substitution was investigated for cases where ESR data are available for comparison

Conceptual design of a DOT farm generator station

NARCIS (Netherlands)

Michailidis, D.; Diepeveen, N.F.B.

2011-01-01

The Delft Offshore Turbine (DOT) is a DUWIND research project that focuses on reducing the cost of offshore wind energy by bringing a radical change in offshore wind turbine technology. The main concept is to centralize electricity generation by having individual wind turbines create a flow of

Education's impact on explanations of radical right-wing voting

NARCIS (Netherlands)

Lubbers, M.; Tolsma, J.

2011-01-01

One of the reactions to the large demographic changes in Europe due to migration has been the rise of radical right-wing parties. Previous research has shown that education is one of the most relevant explanations of this voting behaviour. By pooling the European Social Surveys from 2002, 2004, 2006

Reactions of organic free radicals at colloidal silver in aqueous solution. Electron pool effect and water decomposition

International Nuclear Information System (INIS)

Henglein, A.

1979-01-01

Organic free radicals of high negative redox potential such as α-alcohol radicals were found to transfer electrons to colloidal silver particles stabilized by sodium dodecyl sulfate in aqueous solution. The colloidal particles thus became a pool of stored electrons that could reduce water to form hydrogen or react with suitable acceptors in solution. The organic radicals were produced by irradiation, using suitable scavengers for the primary radicals from the radiolysis of the aqueous solvent. The solutions initially contained silver ions at 1 x 10 -4 - 2 x 10 -3 M. At doses below 10 5 rd, the silver ions were completely reduced to form the colloidal catalyst. In this dose range, the corresponding hydrogen yield amounted to 1 molecule per 100 eV. It increased steeply at higher doses up to 3 molecules per 100 eV. The H 2 yield decreased with increasing dose rate and with increasing pH in alkaline solutions. It was highest at a concentration of sodium dodecyl sulfate of 1 x 10 -3 M, i.e., far below the critical micelle concentration of this surfactant. Changes in the absorption spectrum of the colloid are attributed to changes in the size of the silver particles upon charging up with electrons. The competition of radical-colloid reactions with radical-radical deactivation in the bulk of solution or at the surface of the colloidal particles is also discussed. 11 figures

Semantic Radicals Contribute More Than Phonetic Radicals to the Recognition of Chinese Phonograms: Behavioral and ERP Evidence in a Factorial Study

Directory of Open Access Journals (Sweden)

Xieshun Wang

2017-12-01

Full Text Available The Chinese phonograms consist of a semantic radical and a phonetic radical. The two types of radicals have different functional contributions to their host phonogram. The semantic radical typically signifies the meaning of the phonogram, while the phonetic radical usually contains a phonological clue to the phonogram’s pronunciation. However, it is still unclear how they interplay with each other when we attempt to recognize a phonogram because previous studies rarely manipulated the functionality of the two types of radicals in a single design. Using a full factorial design, the present study aimed to probe this issue by directly manipulating the functional validity of the two types of radicals in a lexical decision task with both behavioral and event-related potential (ERP measurements. The results showed that recognition of phonograms which were related to their semantic radicals in meaning took a shorter reaction time, showed a lower error rate, and elicited a smaller P200 and a larger N400 than did recognition of those which had no semantic relation with their semantic radicals. However, the validity of phonetic radicals did not show any main effect or interaction with that of semantic radicals on either behavioral or ERP measurements. These results indicated that semantic radicals played a dominant role in the recognition of phonograms. Transparent semantic radicals, which provide valid semantic cues to phonograms, can facilitate the recognition of phonograms.

Pyrimidine nucleobase radical reactivity in DNA and RNA

Science.gov (United States)

Greenberg, Marc M.

2016-11-01

Nucleobase radicals are major products of the reactions between nucleic acids and hydroxyl radical, which is produced via the indirect effect of ionizing radiation. The nucleobase radicals also result from hydration of cation radicals that are produced via the direct effect of ionizing radiation. The role that nucleobase radicals play in strand scission has been investigated indirectly using ionizing radiation to generate them. More recently, the reactivity of nucleobase radicals resulting from formal hydrogen atom or hydroxyl radical addition to pyrimidines has been studied by independently generating the reactive intermediates via UV-photolysis of synthetic precursors. This approach has provided control over where the reactive intermediates are produced within biopolymers and facilitated studying their reactivity. The contributions to our understanding of pyrimidine nucleobase radical reactivity by this approach are summarized.

Quantification of hydroxyl radical produced during phacoemulsification.

Science.gov (United States)

Gardner, Jonathan M; Aust, Steven D

2009-12-01

To quantitate hydroxyl radicals produced during phacoemulsification with various irrigating solutions and conditions used in cataract surgery. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. All experiments were performed using an Infiniti Vision System phacoemulsifier with irrigation and aspiration. Hydroxyl radicals were quantitated using electron spin resonance spectroscopy and a spectrophotometric assay for malondialdehyde, which is formed by the oxidation of deoxyribose by the hydroxyl radical. Hydroxyl radical production increased during longitudinal-stroking phacoemulsification as power levels were increased in a nonlinear, nonexponential fashion. The detection of hydroxyl radical was reduced in irrigating solutions containing organic molecules (eg, citrate, acetate, glutathione, dextrose) and further reduced in Navstel, an irrigating solution containing a viscosity-modifying agent, hydroxypropyl methylcellulose. Hydroxyl radicals produced in settings representative of those used in phacoemulsification cataract surgery were quantitated using the deoxyribose method. Hydroxyl radical production was dependent on the level of ultrasound power applied and the irrigating solution used. Oxidative stress on the eye during phacoemulsification may be minimized by using irrigating solutions that contain organic molecules, including the viscosity-modifying agent hydroxypropyl methylcellulose, that can compete for reaction with hydroxyl radicals.

Free radicals in biology. Volume II

International Nuclear Information System (INIS)

Pryor, W.A.

1976-01-01

This volume continues the treatment of topics in free radical biology and free radical pathology from Volume I. In the first chapter, pyridinyl radicals, radicals which are models for those derived from NAD, are discussed. Pyridinyl radicals can be synthesized and isolated and directly studied in a number of chemical systems. The next chapter treats the role of glutathione in the cell. It is becoming even more apparent that this vital thiol controls a large number of important cellular functions. The GSH/GSSG balance has recently been implicated as a control for cellular development; this balance also may be important in relaying the effects of oxidants from one site to another in the body. The next chapter outlines the reactions of singlet oxygen; some of these involve free radicals and some do not. This reactive intermediate appears to be important both in photochemical smog and in cellular chemistry where singlet oxygen is produced by nonphotochemical processes. The production of free radicals from dry tissues, a controversial area with conflicting claims is reviewed. The next chapter outlines the current status of the studies of photochemical smog. The next two chapters treat specific reactive materials which are present in smog. The first discusses the chemistry of nitrogen oxides and ozone. The second chapter treats the chemistry of the peroxyacyl nitrites. These compounds, although present in only small concentration, are among the most toxic components of smog. The last two chapters treat radiation damage to proteins and radiation protection and radical reactions produced by radiation in nucleic acids

Toward conceptualizations in nursing: harbingers from the sciences and humanities.

Science.gov (United States)

Aamodt, A M

1992-01-01

Conceptualizations of care and caring generated from ethnographic study of Tohono O'odham children, Norwegian-Americans, elderly clients in nursing clinics, preschoolers, children with cancer, and gender differences is outlined. Where research questions came from during life experiences of the author, a journey of nursing scholarship viewed from concepts of context development, transformation and care, and "Where do we go from here?" serve as the outline for a discussion of the generation of conceptualizations. A question for nursing research is proposed: What characteristics of care promote human responses for quality human experience? Suggestions for nursing research in the future emphasize the potential of human responses, variations in conceptualizations of care during the life cycles of human beings living in diverse cultural contexts, and changes in conceptualizations of care over time.

O conceito de mal radical The concept of radical evil

Directory of Open Access Journals (Sweden)

Adriano Correia

2005-01-01

Full Text Available A noção de mal radical aparece em Kant no contexto da discussão da religião nos limites da simples razão e busca dar conta da complexa relação entre o respeito pela lei moral e o amor-próprio na definição do móbil para a ação. Na busca por identificar o fundamento da propensão para o mal no homem, Kant se vê diante da dificuldade de ter de articular natureza e liberdade, e ainda que a noção de mal radical possa conservar algumas ambigüidades, permite conceber uma noção de responsabilidade compatível com uma inata propensão para o mal. Neste texto busco explicitar alguns passos fundamentais na construção do conceito por Kant.The concept of radical evil appears in Kant's theory when he discusses the religion in the limits of the mere reason and aims explain the complex relationship between respect for the moral law and the self-love, for establish the motive of the action. By aiming identify the basis of human inclination to evil, Kant is faced with the trouble of have to put nature and freedom in connection. Despite of the concept of radical evil retain some ambiguity, it allows conceive a notion of responsibility suitable to an inherent inclination to evil. In this paper is my purpose to explain some basic moments of Kantian formulation of that notion.

Using Item Response Theory to Conduct a Distracter Analysis on Conceptual Inventory of Natural Selection

Science.gov (United States)

Battisti, Bryce Thomas; Hanegan, Nikki; Sudweeks, Richard; Cates, Rex

2010-01-01

Concept inventories are often used to assess current student understanding although conceptual change models are problematic. Due to controversies with conceptual change models and the realities of student assessment, it is important that concept inventories are evaluated using a variety of theoretical models to improve quality. This study used a…

Involvement of active oxygen in lipid peroxide radical reaction of epidermal homogenate following ultraviolet light exposure

International Nuclear Information System (INIS)

Nishi, J.; Ogura, R.; Sugiyama, M.; Hidaka, T.; Kohno, M.

1991-01-01

To elucidate the radical mechanism of lipid peroxidation induced by ultraviolet light (UV) irradiation, an electron spin resonance (ESR) study was made on epidermal homogenate prepared from albino rat skin. The exposure of the homogenate to UV light resulted in an increase in lipid peroxide content, which was proportional to the time of UV exposure. Using ESR spin trapping (dimethyl-1-pyrroline-N-oxide, DMPO), the DMPO spin adduct spectrum of lipid radicals (L.) was measured following UV exposure (DMPO-L.:aN = 15.5 G, aH = 22.7 G), as was the spectrum of DMPO-hydroxyl radical (DMPO-OH, aN = aH = 15.5 G). In the presence of superoxide dismutase, the DMPO spin adduct spectrum of lipid radicals was found to be reduced remarkably. Therefore, it was shown that the generation of the lipid radicals partially involves superoxide anion radicals, in addition to hydroxyl radicals. In the ESR free-radical experiment, an ESR signal appeared at g = 2.0064 when the ESR tube filled with homogenate was exposed to UV light at -150 degrees C. The temperature-dependent change in the ESR free radical signal of homogenate exposed to UV light was observed at temperatures varying from -150 degrees C to room temperature. By using degassed samples, it was confirmed that oxygen is involved in the formation of the lipid peroxide radicals (LOO.) from the lipid radicals (L.)

HPLC-ESR techniques for detection of complex trapped radicals

International Nuclear Information System (INIS)

Tu Tiecheng; Dong Jirong; Lin Nianyun; Xie Leidong; Liu Rengzhong

1992-01-01

High performance liquid chromatography (HPLC) and ESR combined examination of radical species is an advanced techniques for separation and identification of complex radical species. At SRCL, Waters 990 HPLC has been used to separate the complex trapped radicals and Varian E-112 ESR spectrometer to record the spectra of single trapped radicals after HPLC separation. The advantages of the combined techniques are described as bellow: HPLC is used to separate the long-lived complex trapped radicals derived from reaction of short-lived radicals with spin trap. ESR spectra from single trapped radicals, obtained following HPLC separation of complex trapped radicals, are recorded one by one and well resolved. The structures of short-lived radicals can be inferred from the ESR spectra of the long-lived trapped radicals

Scavenging of free-radical metabolites of aniline xenobiotics and drugs by amino acid derivatives: toxicological implications of radical-transfer reactions.

Science.gov (United States)

Michail, Karim; Baghdasarian, Argishti; Narwaley, Malyaj; Aljuhani, Naif; Siraki, Arno G

2013-12-16

We investigated a novel scavenging mechanism of arylamine free radicals by poly- and monoaminocarboxylates. Free radicals of arylamine xenobiotics and drugs did not react with oxygen in peroxidase-catalyzed reactions; however, they showed marked oxygen uptake in the presence of an aminocarboxylate. These free-radical intermediates were identified using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and electron paramagnetic resonance (EPR) spectrometry. Diethylenetriaminepentaacetic acid (DTPA), a polyaminocarboxylate, caused a concentration-dependent attenuation of N-centered radicals produced by the peroxidative metabolism of arylamines with the subsequent formation of secondary aliphatic carbon-centered radicals stemming from the cosubstrate molecule. Analogously, N,N-dimethylglycine (DMG) and N-methyliminodiacetate (MIDA), but not iminodiacetic acid (IDA), demonstrated a similar scavenging effect of arylamine-derived free radicals in a horseradish peroxidase/H2O2 system. Using human promyelocytic leukemia (HL-60) cell lysate as a model of human neutrophils, DTPA, MIDA, and DMG readily reduced anilinium cation radicals derived from the arylamines and gave rise to the corresponding carbon radicals. The rate of peroxidase-triggered polymerization of aniline was studied as a measure of nitrogen-radical scavenging. Although, IDA had no effect on the rate of aniline polymerization, this was almost nullified in the presence of DTPA and MIDA at half of the molar concentration of the aniline substrate, whereas a 20 molar excess of DMPO caused only a partial inhibition. Furthermore, the yield of formaldehyde, a specific reaction endproduct of the oxidation of aminocarboxylates by aniline free-radical metabolites, was quantitatively determined. Azobenzene, a specific reaction product of peroxidase-catalyzed free-radical dimerization of aniline, was fully abrogated in the presence of DTPA, as confirmed by GC/MS. Under aerobic conditions, a radical-transfer reaction

Particle size-dependent radical generation from wildland fire smoke

International Nuclear Information System (INIS)

Leonard, Stephen S.; Castranova, Vince; Chen, Bean T.; Schwegler-Berry, Diane; Hoover, Mark; Piacitelli, Chris; Gaughan, Denise M.

2007-01-01

ultrafine particles also caused significant increases in H 2 O 2 production by monocytes and lipid peroxidation. All particle sizes showed the ability to cause DNA damage. These results indicate that the radical generation and the damage caused by them is not only a function of surface area but is also influenced by changing chemical and other characteristics due to particle size

Reactions of carbonate radical with cobalt(II) aminopolycarboxylates

International Nuclear Information System (INIS)

Mandal, P.C.; Bardhan, D.K.; Bhattacharyya, S.N.

1992-01-01

Reactions of carbonate (CO 3 - radical) and bicarbonate (HCO 3 radical) radicals generated by photolysis of a carbonate or bicarbonate solution at pH 11.2 and 8.5, respectively, with Co(II) complexes of iminodiacetic acid (IDA) and ethylenediaminetetraacetic acid (EDTA) have been studied. The rate constants for the reactions were in the order of 10 6 -10 7 dm 3 mol -1 s -1 . From the time-resolved spectroscopy of the products formed after reaction of CO 3 - radical or HCO 3 radical, it is observed that CO 3 - radical or HCO 3 radical oxidize the metal center to its higher oxidation state. (author) 26 refs.; 2 figs.; 1 tab

Annex to 7-GeV Advanced Photon Source Conceptual Design Report

International Nuclear Information System (INIS)

1988-05-01

The Annex to the 7-GeV Advanced Photon Source Conceptual Design Report updates the Conceptual Design Report of 1987 (CDR-87) to include the results of further optimization and changes of the design during the past year. The design changes can be summarized as affecting three areas: the accelerator system, conventional facilities, and experimental systems. Most of the changes in the accelerator system result from inclusion of a positron accumulator ring (PAR), which was added at the suggestion of the 1987 DOE Review Committee, to speed up the filling rate of the storage ring. The addition of the PAR necessitates many minor changes in the linac system, the injector synchrotron, and the low-energy beam transport lines. 63 figs., 18 tabs

Self-Terminating, Oxidative Radical Cyclizations

Directory of Open Access Journals (Sweden)

Uta Wille

2004-05-01

Full Text Available The recently discovered novel concept of self-terminating, oxidative radical cyclizations, through which alkynes can be converted into carbonyl compounds under very mild reaction conditions using O-centered inorganic and organic radicals as oxidants, is described

Third-order nonlinear optical properties of open-shell supermolecular systems composed of acetylene linked phenalenyl radicals.

Science.gov (United States)

Nakano, Masayoshi; Kishi, Ryohei; Yoneda, Kyohei; Inoue, Yudai; Inui, Tomoya; Shigeta, Yasuteru; Kubo, Takashi; Champagne, Benoît

2011-08-11

The third-order nonlinear optical (NLO) properties, at the molecular level, the static second hyperpolarizabilities, γ, of supermolecular systems composed of phenalenyl and pyrene rings linked by acetylene units are investigated by employing the long-range corrected spin-unrestricted density functional theory, LC-UBLYP, method. The phenalenyl based superethylene, superallyl, and superbutadiene in their lowest spin states have intermediate diradical characters and exhibit larger γ values than the closed-shell pyrene based superpolyene systems. The introduction of a positive charge into the phenalenyl based superallyl radical changes the sign of γ and enhances its amplitude by a factor of 35. Although such sign inversion is also observed in the allyl radical and cation systems in their ground state equilibrium geometries, the relative amplitude of γ is much different, that is, |γ(regular allyl cation)/γ(regular allyl radical)| = 0.61 versus |γ(phenalenyl based superallyl cation)/γ(phenalenyl based superallyl radical)| = 35. In contrast, the model ethylene, allyl radical/cation, and butadiene systems with stretched carbon-carbon bond lengths (2.0 Å), having intermediate diradical characters, exhibit similar γ features to those of the phenalenyl based superpolyene systems. This exemplifies that the size dependence of γ as well as its sign change by introducing a positive charge on the phenalenyl based superpolyene systems originate from their intermediate diradical characters. In addition, the change from the lowest to the highest π-electron spin states significantly reduces the γ amplitudes of the neutral phenalenyl based superpolyene systems. For phenalenyl based superallyl cation, the sign inversion of γ (from negative to positive) is observed upon switching between the singlet and triplet states, which is predicted to be associated with a modification of the balance between the positive and negative contributions to γ. The present study paves the way

Move-tecture: A Conceptual Framework for Designing Movement in Architecture

Science.gov (United States)

Yilmaz, Irem

2017-10-01

Along with the technological improvements in our age, it is now possible for the movement to become one of the basic components of the architectural space. Accordingly, architectural construction of movement changes both our architectural production practices and our understanding of architectural space. However, existing design concepts and approaches are insufficient to discuss and understand this change. In this respect, this study aims to form a conceptual framework on the relationship of architecture and movement. In this sense, the conceptualization of move-tecture is developed to research on the architectural construction of movement and the potentials of spatial creation through architecturally constructed movement. Move-tecture, is a conceptualization that treats movement as a basic component of spatial creation. It presents the framework of a qualitative categorization on the design of moving architectural structures. However, this categorization is a flexible one that can evolve in the direction of the expanding possibilities of the architectural design and the changing living conditions. With this understanding, six categories have been defined within the context of the article: Topological Organization, Choreographic Formation, Kinetic Structuring, Corporeal Constitution, Technological Configuration and Interactional Patterning. In line with these categories, a multifaceted perspective on the moving architectural structures is promoted. It is aimed that such an understanding constitutes a new initiative in the design practices carried out in this area and provides a conceptual basis for the discussions to be developed.

Origin and evolution of the free radical theory of aging: a brief personal history, 1954–2009.

Science.gov (United States)

Harman, Denham

2009-12-01

Aging is the progressive accumulation in an organism of diverse, deleterious changes with time that increase the chance of disease and death. The basic chemical process underlying aging was first advanced by the free radical theory of aging (FRTA) in 1954: the reaction of active free radicals, normally produced in the organisms, with cellular constituents initiates the changes associated with aging. The involvement of free radicals in aging is related to their key role in the origin and evolution of life. The initial low acceptance of the FRTA by the scientific community, its slow growth, manifested by meetings and occasional papers based on the theory, prompted this account of the intermittent growth of acceptance of the theory over the past nearly 55 years.

Effect of shear stress and free radicals induced by ultrasound on erythrocytes

International Nuclear Information System (INIS)

Kondo, T.; Fukushima, Y.; Kon, H.; Riesz, P.

1989-01-01

The present study was undertaken to elucidate the mechanism of hemolysis induced by ultrasound. Ar or N2O gas was used to distinguish between cavitation with or without free radical formation (hydroxyl radicals and hydrogen atoms). Free radical formation was examined by the method of spin trapping combined with ESR. After sonication of erythrocyte suspensions, several structural and functional parameters of the erythrocyte membrane--hemolysis, membrane fluidity, membrane permeability, and membrane deformability--were examined. Although free radical formation was observed in the erythrocyte suspensions sonicated in the presence of Ar, no free radical formation was observed in the presence of N2O. However, the hemolysis behavior induced by ultrasound was similar in the presence of Ar or N2O. The membrane fluidity, permeability, and deformability of the remaining unlysed erythrocytes after sonication in the presence of Ar or N2O were unchanged and identical to those of the control cells. On the other hand, after gamma irradiation (700 Gy), the hemolysis behavior was quite different from that after sonication, and the membrane properties were significantly changed. These results suggest that hemolysis induced by sonication was due to mechanical shearing stress arising from cavitation, and that the membrane integrity of the remaining erythrocytes after sonication was the same as that of control cells without sonication. The triatomic gas, N2O, may be useful for ultrasonically disrupting cells without accompanying free radical formation

Conceptual Change and Science Achievement Related to a Lesson Sequence on Acids and Bases Among African American Alternative High School Students: A Teacher's Practical Arguments and the Voice of the "Other"

Science.gov (United States)

Wood, Lynda Charese

The study of teaching and learning during the period of translating ideals of reform into classroom practice enables us to understand student-teacher-researcher symbiotic learning. In line with this assumption, the purpose of this study is threefold:(1) observe effects of the Common Knowledge Construction Model (CKCM), a conceptual change inquiry model of teaching and learning, on African American students' conceptual change and achievement; (2) observe the shift in teacher's practical arguments; and (3) narrate the voice of "the Other" about teacher professional learning. This study uses retrospective data from a mixed-method approach consisting of Phenomenography, practical arguments and story-telling. Data sources include audio-recordings of a chemistry teacher's individual interviews of her students' prior- and post-intervention conceptions of acids and bases; results of Acid-Base Achievement Test (ABA-T); video-recordings of a chemistry teacher's enactment of CKCM acid-base lesson sequence; audio-recordings of teacher-researcher reflective discourse using classroom video-clips; teacher interviews; and teacher and researcher personal reflective journals. Students' conceptual changes reflect change in the number of categories of description; shift in language use from everyday talk to chemical talk; and development of a hierarchy of chemical knowledge. ABA-T results indicated 17 students in the experimental group achieved significantly higher scores than 22 students in the control group taught by traditional teaching methods. The teacher-researcher reflective discourse about enactment of the CKCM acid-base lesson sequence reveals three major shifts in teacher practical arguments: teacher inadequate preparedness to adequate preparedness; lack of confidence to gain in confidence; and surface learning to deep learning. The developing story uncovers several aspects about teaching and learning of African American students: teacher caring for the uncared; cultivating

Interacting Conceptual Spaces

OpenAIRE

Bolt, Josef; Coecke, Bob; Genovese, Fabrizio; Lewis, Martha; Marsden, Daniel; Piedeleu, Robin

2016-01-01

We propose applying the categorical compositional scheme of [6] to conceptual space models of cognition. In order to do this we introduce the category of convex relations as a new setting for categorical compositional semantics, emphasizing the convex structure important to conceptual space applications. We show how conceptual spaces for composite types such as adjectives and verbs can be constructed. We illustrate this new model on detailed examples.

Oxidation of aromatic amines and diamines by OH radicals. Formation and ionization constants of amine cation radicals in water

International Nuclear Information System (INIS)

Hayon, E.; Rao, P.S.

1975-01-01

The one-electron oxidation by hydroxyl radicals of aromatic amines and diamines in water was studied using the fast-reaction technique of pulse radiolysis and kinetic absorption spectrophotometry. The following compounds were examined: N,N,N 1 ,N 1 - tetramethyl-p-phenylenediamine (TMPD), p-phenylenediamine (PD), N,N-dimethyl-p-phenylenediamene (DMPD), N,N,N 1 ,N 1 -tetramethylbenzidine (TMB), and diphenylamine (DPA). The main initial reaction of the OH radicals is suggested to be an addition to these compounds to give absorption spectra which absorb strongly in the visible and uv regions. These OH radical adducts decay by first-order kinetics and have lifetimes of approximately 5-50 μsec, dependent on the pH, buffer concentration, and the nature of the aromatic amines and diamines. They decay to give species with somewhat similar absorption spectra and extinction coefficients, which are very long lived in the absence of oxygen. The latter species are assigned to the cation radicals TMPD. + , PD. + , DMPD. + , TMB. + , and DPA. + . The OH radical adducts and the cation radicals have acid-base properties. The pK/sub a/ values of the cation radicals TMPDH. 2+ , PDH. 2+ , DMPDH. 2+ , TMBH. 2+ , and DPAH. 2+ were found to be 5.3, 5.9, 6.1, 5.1, and 4.2, respectively. The results indicate that these aromatic amines and diamines can be oxidized by free radicals to yield the corresponding cation radicals. (U.S.)

Sexual functioning and vaginal changes after radical vaginal trachelectomy in early stage cervical cancer patients: a longitudinal study

DEFF Research Database (Denmark)

Froeding, LP; Ottesen, C; Rung-Hansen, H

2014-01-01

Radical vaginal trachelectomy (RVT) offers low complication rate, good survival, and possibility for future childbearing for young women with early stage cervical cancer. However, the literature on quality of life (QOL) and sexual functioning in patients undergoing RVT is scarce.......Radical vaginal trachelectomy (RVT) offers low complication rate, good survival, and possibility for future childbearing for young women with early stage cervical cancer. However, the literature on quality of life (QOL) and sexual functioning in patients undergoing RVT is scarce....

The nexus between climate change, ecosystem services and human health: Towards a conceptual framework.

Science.gov (United States)

Chiabai, Aline; Quiroga, Sonia; Martinez-Juarez, Pablo; Higgins, Sahran; Taylor, Tim

2018-09-01

This paper addresses the impact that changes in natural ecosystems can have on health and wellbeing focusing on the potential co-benefits that green spaces could provide when introduced as climate change adaptation measures. Ignoring such benefits could lead to sub-optimal planning and decision-making. A conceptual framework, building on the ecosystem-enriched Driver, Pressure, State, Exposure, Effect, Action model (eDPSEEA), is presented to aid in clarifying the relational structure between green spaces and human health, taking climate change as the key driver. The study has the double intention of (i) summarising the literature with a special emphasis on the ecosystem and health perspectives, as well as the main theories behind these impacts, and (ii) modelling these findings into a framework that allows for multidisciplinary approaches to the underlying relations between human health and green spaces. The paper shows that while the literature based on the ecosystem perspective presents a well-documented association between climate, health and green spaces, the literature using a health-based perspective presents mixed evidence in some cases. The role of contextual factors and the exposure mechanism are rarely addressed. The proposed framework could serve as a multidisciplinary knowledge platform for multi-perspecitve analysis and discussion among experts and stakeholders, as well as to support the operationalization of quantitative assessment and modelling exercises. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Radicalización ideológico-política y terrorismo: un enfoque psicosocial (Ideological-political radicalization and terrorism: a psychosocial approach

Directory of Open Access Journals (Sweden)

Jorge Torres-Marín

2017-08-01

Full Text Available Ideological-political radicalization and terrorism generate a series of disastrous consequences for the correct functioning of society. Nowadays, polarization and ideological-political radicalization are on the rise. Factors contributing to this are situations of social upheaval like the migratory and economic crisis, as well as terrorism of an ideological-religious nature. The proposal of effective preventive interventions requires a multidisciplinary and systematic study of the phenomenon, in which social psychology is destined to play a central role. The aim of the current revision is to compile a comprehensive proposal of a conceptual nature, which will illustrate the psychosocial processes underlying violent radicalization of groups with extreme political ideologies. Specifically, the aim is to highlight the suitability of analyzing a set of psychosocial variables, which play an essential role in an individual’s personal balance, related to terrorists’ recruitment and the maintenance of extremist groups. Likewise, and as a response to the need to consider new research perspectives when studying the terrorism phenomenon, the part of victimization and competitive victimization in explaining terrorism is analyzed. The findings suggest enough theoretical links to encourage the integration of these constructs in future research.

Near-Infrared Free-Radical and Free-Radical-Promoted Cationic Photopolymerizations by In-Source Lighting Using Upconverting Glass.

Science.gov (United States)

Kocaarslan, Azra; Tabanli, Sevcan; Eryurek, Gonul; Yagci, Yusuf

2017-11-13

A method is presented for the initiation of free-radical and free-radical-promoted cationic photopolymerizations by in-source lighting in the near-infrared (NIR) region using upconverting glass (UCG). This approach utilizes laser irradiation of UCG at 975 nm in the presence of fluorescein (FL) and pentamethyldiethylene triamine (PMDETA). FL excited by light emitted from the UCG undergoes electron-transfer reactions with PMDETA to form free radicals capable of initiating polymerization of methyl methacrylate. To execute the corresponding free-radical-promoted cationic polymerization of cyclohexene oxide, isobutyl vinyl ether, and N-vinyl carbazole, it was necessary to use FL, dimethyl aniline (DMA), and diphenyliodonium hexafluorophosphate as sensitizer, coinitiator, and oxidant, respectively. Iodonium ions promptly oxidize DMA radicals formed to the corresponding cations. Thus, cationic polymerization with efficiency comparable to the conventional irradiation source was achieved. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Knowledge is power: how conceptual knowledge transforms visual cognition.

Science.gov (United States)

Collins, Jessica A; Olson, Ingrid R

2014-08-01

In this review, we synthesize the existing literature demonstrating the dynamic interplay between conceptual knowledge and visual perceptual processing. We consider two theoretical frameworks that demonstrate interactions between processes and brain areas traditionally considered perceptual or conceptual. Specifically, we discuss categorical perception, in which visual objects are represented according to category membership, and highlight studies showing that category knowledge can penetrate early stages of visual analysis. We next discuss the embodied account of conceptual knowledge, which holds that concepts are instantiated in the same neural regions required for specific types of perception and action, and discuss the limitations of this framework. We additionally consider studies showing that gaining abstract semantic knowledge about objects and faces leads to behavioral and electrophysiological changes that are indicative of more efficient stimulus processing. Finally, we consider the role that perceiver goals and motivation may play in shaping the interaction between conceptual and perceptual processing. We hope to demonstrate how pervasive such interactions between motivation, conceptual knowledge, and perceptual processing are in our understanding of the visual environment, and to demonstrate the need for future research aimed at understanding how such interactions arise in the brain.

Electron spin resonance study of radicals in irradiated polyethylene

International Nuclear Information System (INIS)

Fujimura, Takashi

1979-02-01

In order to elucidate radiation effect in polyethylene, the nature and behavior of radicals produced in polyethylene and the model compound of polyethylene irradiated at 77 0 K were studied by using electron spin resonance. The structure of radical pairs, which are composed of two radicals produced very closely each other, was investigated in drawn polyethylene and the single crystal of n-eicosane. The radical pairs of intrachain type and interchain type were found in polyethylene and n-eicosane respectively. It was suggested that these two types of radical pairs are the precursors of double bonds and crosslinks respectively. The thermal decay reactions of radicals themselves produced in irradiated polyethylene were investigated. It was made clear that the short range distances between two radicals play an important role in the decay reaction of alkyl radicals at low temperatures. The trapping regions of radicals were studied and it was clarified that allyl radicals, which are produced by the reaction of alkyl radicals with double bonds, are trapped both in the crystalline and non-crystalline regions. (author)

Redox properties of free radicals

International Nuclear Information System (INIS)

Neta, P.

1981-01-01

Results of electron transfer reactions observed and monitored by pulse radiolysis are reported. This technique allows determination of the first one-electron reduction or oxidation of a compound rather than the overall two-electron transfer usually reported. Pulse radiolysis allows the determination of absolute rate constants for reactions of free radicals and helps elucidate the mechanisms involved. Studies using this technique to study radicals derived from quinones, nitro compounds, pyridines, phenols, and anilines are reported. Radicals of biochemical interest arising from riboflavin, ascorbic acid, vitamin K 3 , vitamin E, MAD + , porphyrins, etc. have also been studied

Hot wire radicals and reactions

International Nuclear Information System (INIS)

Zheng Wengang; Gallagher, Alan

2006-01-01

Threshold ionization mass spectroscopy is used to measure radical (and stable gas) densities at the substrate of a tungsten hot wire (HW) reactor. We report measurements of the silane reaction probability on the HW and the probability of Si and H release from the HW. We describe a model for the atomic H release, based on the H 2 dissociation model. We note major variations in silicon-release, with dependence on prior silane exposure. Measured radical densities versus silane pressure yield silicon-silane and H-silane reaction rate coefficients, and the dominant radical fluxes to the substrate

Pathways of change explaining the effect of smoke-free legislation on smoking cessation in the Netherlands: an application of the international tobacco control conceptual model

NARCIS (Netherlands)

Nagelhout, G.E.; de Vries, H.; Fong, G.T.; Candel, M.J.J.M.; Thrasher, J.F.; van den Putte, B.; Thompson, M.E.; Cummings, K.M.; Willemsen, M.C.

2012-01-01

Introduction: This study aims to test the pathways of change from individual exposure to smoke-free legislation on smoking cessation, as hypothesized in the International Tobacco Control (ITC) Conceptual Model. Methods: A nationally representative sample of Dutch smokers aged 15 years and older was

Evolution of material properties during free radical photopolymerization

Science.gov (United States)

Wu, Jiangtao; Zhao, Zeang; Hamel, Craig M.; Mu, Xiaoming; Kuang, Xiao; Guo, Zaoyang; Qi, H. Jerry

2018-03-01

Photopolymerization is a widely used polymerization method in many engineering applications such as coating, dental restoration, and 3D printing. It is a complex chemical and physical process, through which a liquid monomer solution is rapidly converted to a solid polymer. In the most common free-radical photopolymerization process, the photoinitiator in the solution is exposed to light and decomposes into active radicals, which attach to monomers to start the polymerization reaction. The activated monomers then attack Cdbnd C double bonds of unsaturated monomers, which leads to the growth of polymer chains. With increases in the polymer chain length and the average molecular weight, polymer chains start to connect and form a network structure, and the liquid polymer solution becomes a dense solid. During this process, the material properties of the cured polymer change dramatically. In this paper, experiments and theoretical modeling are used to investigate the free-radical photopolymerization reaction kinetics, material property evolution and mechanics during the photopolymerization process. The model employs the first order chemical reaction rate equations to calculate the variation of the species concentrations. The degree of monomer conversion is used as an internal variable that dictates the mechanical properties of the cured polymer at different curing states, including volume shrinkage, glass transition temperature, and nonlinear viscoelastic properties. To capture the nonlinear behavior of the cured polymer under low temperature and finite deformation, a multibranch nonlinear viscoelastic model is developed. A phase evolution model is used to describe the mechanics of the coupling between the crosslink network evolution and mechanical loading during the curing process. The comparison of the model and the experimental results indicates that the model can capture property changes during curing. The model is further applied to investigate the internal stress

Synthesis and Characterization of Ethylenedithio-MPTTF-PTM Radical Dyad as a Potential Neutral Radical Conductor

DEFF Research Database (Denmark)

Souto, Manuel; Bendixen, Dan; Jensen, Morten

2016-01-01

During the last years there has been a high interest in the development of new purely-organic single-component conductors. Very recently, we have reported a new neutral radical conductor based on the perchlorotriphenylmethyl (PTM) radical moiety linked to a monopyrrolo-tetrathiafulvalene (MPTTF...

A Conceptual Framework for Ambient Learning Displays

NARCIS (Netherlands)

Börner, Dirk; Kalz, Marco; Specht, Marcus

2010-01-01

Börner, D., Kalz, M., & Specht, M. (2010). A Conceptual Framework for Ambient Learning Displays. In B. Chang, T. Hirashima, & H. Ogata (Eds.), Joint Proceedings of the Work-in-Progress Poster and Invited Young Researcher Symposium for the 18th International Conference on Computers in Education (pp.

Our evolving conceptual model of the coastal eutrophication problem

Science.gov (United States)

Cloern, James E.

2001-01-01

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5

Singlet Oxygen and Free Radical Reactions of Retinoids and Carotenoids—A Review

Science.gov (United States)

Truscott, T. George

2018-01-01

We report on studies of reactions of singlet oxygen with carotenoids and retinoids and a range of free radical studies on carotenoids and retinoids with emphasis on recent work, dietary carotenoids and the role of oxygen in biological processes. Many previous reviews are cited and updated together with new data not previously reviewed. The review does not deal with computational studies but the emphasis is on laboratory-based results. We contrast the ease of study of both singlet oxygen and polyene radical cations compared to neutral radicals. Of particular interest is the switch from anti- to pro-oxidant behavior of a carotenoid with change of oxygen concentration: results for lycopene in a cellular model system show total protection of the human cells studied at zero oxygen concentration, but zero protection at 100% oxygen concentration. PMID:29301252

Meaningful main effects or intriguing interactions? Examining the influences of epistemic beliefs and knowledge representations on cognitive processing and conceptual change when learning physics

Science.gov (United States)

Franco, Gina M.

The purpose of this study was to investigate the role of epistemic beliefs and knowledge representations in cognitive and metacognitive processing and conceptual change when learning about physics concepts through text. Specifically, I manipulated the representation of physics concepts in texts about Newtonian mechanics and explored how these texts interacted with individuals' epistemic beliefs to facilitate or constrain learning. In accordance with definitions from Royce's (1983) framework of psychological epistemology, texts were developed to present Newtonian concepts in either a rational or a metaphorical format. Seventy-five undergraduate students completed questionnaires designed to measure their epistemic beliefs and their misconceptions about Newton's laws of motion. Participants then read the first of two instructional texts (in either a rational or metaphorical format), and were asked to think aloud while reading. After reading the text, participants completed a recall task and a post-test of selected items regarding Newtonian concepts. These steps were repeated with a second instructional text (in either a rational or metaphorical format, depending on which format was assigned previously). Participants' think-aloud sessions were audio-recorded, transcribed, and then blindly coded, and their recalls were scored for total number of correctly recalled ideas from the text. Changes in misconceptions were analyzed by examining changes in participants' responses to selected questions about Newtonian concepts from pretest to posttest. Results revealed that when individuals' epistemic beliefs were congruent with the knowledge representations in their assigned texts, they performed better on both online measures of learning (e.g., use of processing strategies) and offline products of learning (e.g., text recall, changes in misconceptions) than when their epistemic beliefs were incongruent with the knowledge representations. These results have implications for how

Free radicals trapped in polyethylene matrix

International Nuclear Information System (INIS)

Shimada, S.; Maeda, M.; Hori, Y.; Kashiwabara, H.

1977-01-01

Two types of alkyl radicals were found to be trapped in irradiated crystals grown from polyethylene solution. One of them corresponds to the broad sextet pattern of the e.s.r. spectrum and the other corresponds to the sharp sextet pattern. The free radicals attributed to the broad sextet began to disappear at a lower temperature than the temperature at which the free radicals attributed to the sharp sextet disappeared. When butadiene molecules were brought into contact with the specimen, the decay of the free radicals corresponding to the broad sextet was accelerated. When the specimen was subjected to fuming nitric acid treatment, no broad sextet was observed. The mat of the crystals was aligned so that the c-axes of its crystallites were perpendicular to its surface. The broad sextet showed no anisotropy when the angle between the direction of applied magnetic field and that of the c-axis of the crystallite was varied. On the other hand, the sharp component of the spectrum showed apparent anisotropy. It can be concluded that the broad component comes from the free radicals trapped in the lamellar surface and the sharp component is attributed to the free radicals trapped in the inner part of the crystallite. (author)

The role of melanin as protector against free radicals in skin and its role as free radical indicator in hair

Science.gov (United States)

Herrling, Thomas; Jung, Katinka; Fuchs, Jürgen

2008-05-01

Throughout the body, melanin is a homogenous biological polymer containing a population of intrinsic, semiquinone-like radicals. Additional extrinsic free radicals are reversibly photo-generated by UV and visible light. Melanin photochemistry, particularly the formation and decay of extrinsic radicals, has been the subject of numerous electron spin resonance (ESR) spectroscopy studies. Several melanin monomers exist, and the predominant monomer in a melanin polymer depends on its location within an organism. In skin and hair, melanin differs in content of eumelanin or pheomelanin. Its bioradical character and its susceptibility to UV irradiation makes melanin an excellent indicator for UV-related processes in both skin and hair. The existence of melanin in skin is strongly correlated with the prevention against free radicals/ROS generated by UV radiation. Especially in the skin melanin (mainly eumelanin) ensures the only natural UV protection by eliminating the generated free radicals/ROS. Melanin in hair can be used as a free radical detector for evaluating the efficacy of hair care products. The aim of this study was to investigate the suitability of melanin as protector of skin against UV generated free radicals and as free radical indicator in hair.

Free radicals generated by radiolysis of aqueous solutions

International Nuclear Information System (INIS)

Schwarz, H.A.

1981-01-01

The free radicals produced in the radiolysis of aqueous solutions span the range of redox potentials from -2.9 to +2.65 volts. The identity and nature of these radicals were discussed. Most of the discussion was results obtained with low LET radiation sources ( 60 Co gamma radiation or electron accelerators). Water radiolysis provides the synthesis of many radicals and radical ions in aqueous solution. The primary radicals, e/sub aq/ - H, OH, are well characterized. The radical population can be made to be 90% pure OH (or O - ) if N 2 O solutions are irradiated, the remaining 10% being H atoms. 55% of the radicals can be converted to H atoms in acid solution or in neutral phosphate solutions(e/sub aq/ - reacts with H 2 PO 4- to produce H). The remaining 45% (OH radicals) are difficult to convert to H by reaction with H 2 , due to the slow rate of the reaction. About 100 atmospheres of H 2 are required to do the conversion in less than 10 - 6 sec. 3 figures, 3 tables. (DP)

Free radicals and antioxidants in primary fibromyalgia: an oxidative stress disorder?

Science.gov (United States)

Bagis, Selda; Tamer, Lulufer; Sahin, Gunsah; Bilgin, Ramazan; Guler, Hayal; Ercan, Bahadir; Erdogan, Canan

2005-04-01

The role of free radicals in fibromyalgia is controversial. In this study, 85 female patients with primary fibromyalgia and 80 age-, height-, and weight-matched healthy women were evaluated for oxidant/antioxidant balance. Malondialdehyde is a toxic metabolite of lipid peroxidation used as a marker of free radical damage. Superoxide dismutase is an intracellular antioxidant enzyme and shows antioxidant capacity. Pain was assessed by visual analog scale. Tender points were assessed by palpation. Age, smoking, body mass index (BMI), and duration of disease were also recorded. Malondialdehyde levels were significantly higher and superoxide dismutase levels significantly lower in fibromyalgic patients than controls. Age, BMI, smoking, and duration of disease did not affect these parameters. We found no correlation between pain and number of tender points. In conclusion, oxidant/antioxidant balances were changed in fibromyalgia. Increased free radical levels may be responsible for the development of fibromyalgia. These findings may support the hypothesis of fibromyalgia as an oxidative disorder.

Radical carbonylations using a continuous microflow system

Directory of Open Access Journals (Sweden)

Takahide Fukuyama

2009-07-01

Full Text Available Radical-based carbonylation reactions of alkyl halides were conducted in a microflow reactor under pressurized carbon monoxide gas. Good to excellent yields of carbonylated products were obtained via radical formylation, carbonylative cyclization and three-component coupling reactions, using tributyltin hydride or TTMSS as a radical mediator.

Radical-Mediated Enzymatic Polymerizations

Science.gov (United States)

Zavada, Scott R.; Battsengel, Tsatsral; Scott, Timothy F.

2016-01-01

Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes―catalytic proteins―owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol–ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

Conceptual structures in practice

CERN Document Server

Hitzler, Pascal

2009-01-01

Exploring fundamental research questions, Conceptual Structures in Practice takes you through the basic yet nontrivial task of establishing conceptual relations as the foundation for research in knowledge representation and knowledge mining. It includes contributions from leading researchers in both the conceptual graph and formal concept analysis (FCA) communities.This accessible, self-contained book begins by providing the formal background in FCA and conceptual graphs. It then describes various software tools for analysis and computation, including the ToscanaJ suite. Written by the origina

Validity of Basic Electronic 1 Module Integrated Character Value Based on Conceptual Change Teaching Model to Increase Students Physics Competency in STKIP PGRI West Sumatera

Science.gov (United States)

Hidayati, A.; Rahmi, A.; Yohandri; Ratnawulan

2018-04-01

The importance of teaching materials in accordance with the characteristics of students became the main reason for the development of basic electronics I module integrated character values based on conceptual change teaching model. The module development in this research follows the development procedure of Plomp which includes preliminary research, prototyping phase and assessment phase. In the first year of this research, the module is validated. Content validity is seen from the conformity of the module with the development theory in accordance with the demands of learning model characteristics. The validity of the construct is seen from the linkage and consistency of each module component developed with the characteristic of the integrated learning model of character values obtained through validator assessment. The average validation value assessed by the validator belongs to a very valid category. Based on the validator assessment then revised the basic electronics I module integrated character values based on conceptual change teaching model.

Direct detection of radicals in intact soybean nodules

DEFF Research Database (Denmark)

Mathieu, C; Moreau, S; Frendo, P

1998-01-01

Electron paramagnetic resonance spectroscopy has been employed to examine the nature of the metal ions and radicals present in intact root nodules of soybean plants grown in the absence of nitrate. The spectra obtained from nodules of different ages using this non-invasive technique show dramatic...... differences, suggesting that there are both qualitative and quantitative changes in the metal ion and radical species present. A major component of the spectra obtained from young nodules is assigned to a complex (Lb-NO) of nitric oxide (NO.) with the heme protein leghemoglobin (Lb). This Lb-NO species, which...... has not been previously detected in intact root nodules of plants grown in the absence of nitrate, is thought to be formed by reaction of nitric oxide with iron(II) leghemoglobin. The nitric oxide may be generated from arginine via a nitric oxide synthase-like activity present in the nodules...

Design of a new research reactor : 1st year conceptual design

International Nuclear Information System (INIS)

Park, Cheol; Lee, B. C.; Chae, H. T.

2004-01-01

A new research reactor model satisfying the strengthened regulatory environments and the changed circumstances around nuclear society should be prepared for the domestic and international demand of research reactor. This can also lead to the improvement of technologies and fostering manpower obtained during the construction and the operation of HANARO. In this aspect, this study has been launched and the 1st year conceptual design has been carried out in 2003. The major tasks performed at the first year of conceptual design stage are as follows; Establishments of general design requirements of research reactors and experimental facilities, Establishment of fuel and reactor core concepts, Preliminary analysis of reactor physics and thermal-hydraulics for conceptual core, Conceptual design of reactor structure and major systems, International cooperation to establish foundations for exporting

Fast reactions of organic anion radicals with organic halides in hexamethylphosphoric triamide studied by pulse radiolysis

International Nuclear Information System (INIS)

Honda, Eiji; Tokuda, Masao; Yoshida, Hiroshi; Ogasawara, Masaaki

1987-01-01

Fast reactions of diethyl fumarate anion radical (DEF - ) and fluorenone anion radical (Fl - ) with various organic halides (RX) in hexamethylphosphoric triamide have been studied by means of ns pulse radiolysis at room temperature. Reactions of acetophenone anion radical were also studied for comparison. It was found that the reaction rate of Fl - was subject to the steric and resonance effects of R groups of RX in accord with the classical concept of S N 2 reactions: the rate constant was reduced by 2 orders of magnitude by the steric effect when R was changed from ethyl to bulky isopropyl or t-butyl, and it was still large by the resonance effect of R even if R was changed from ethyl to an allyl or a benzyl group. While the reaction rate of DEF - was not much affected when R was changed to more bulky groups, the rate constant was correlated to the reduction potential of RX. The results were interpreted in terms of a VB correlation diagram approach or rate-equilibrium relationship within a framework of S N 2 reactions. (author)

Fluorescence lifetime measurement of radical ions

International Nuclear Information System (INIS)

Ichinose, Nobuyuki; Kinugasa, Jun-ichiro; Hagiri, Masahide; Nakayama, Toshihiro; Murakami, Hiroshi; Kishimoto, Maki; Daido, Hiroyuki

2004-01-01

One-photonic excitation of a charge transfer complex of hexamethoxybenzene (HMB) and nitrosonium tetrafluoroborate (NO + BF 4 - ) in acetonitrile afforded fluorescences emission from excited radical cation of HMB (HMB + *). Lifetime of the excited radical ion species was measured to be 7 ps by the pump-probe transient absorption technique. The lifetime was much shorter than that of free radical ion (63 ps), indicating the presence of an interaction between HMB + * and NO in the excited complex. (author)

Generation and propagation of radical reactions on proteins

DEFF Research Database (Denmark)

Hawkins, C L; Davies, Michael Jonathan

2001-01-01

The oxidation of proteins by free radicals is thought to play a major role in many oxidative processes within cells and is implicated in a number of human diseases as well as ageing. This review summarises information on the formation of radicals on peptides and proteins and how radical damage may...... be propagated and transferred within protein structures. The emphasis of this article is primarily on the deleterious actions of radicals generated on proteins, and their mechanisms of action, rather than on enzymatic systems where radicals are deliberately formed as transient intermediates. The final section...

Radical scavenging activity of crude polysaccharides from Camellia sinensis

Directory of Open Access Journals (Sweden)

Yang Fan

2011-01-01

Full Text Available A preparation of crude polysaccharides (TPS was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.

Reactivity Of Radiolytically-Produced Nitrogen Oxide Radicals Toward Aromatic Compounds

International Nuclear Information System (INIS)

Elias, Gracy

2010-01-01

The nitration of aromatic compounds in the gas phase is an important source of toxic, carcinogenic, and mutagenic species in the atmosphere and has therefore received much attention. Gas phase nitration typically occurs by free-radical reactions. Condensed-phase free-radical reactions, and in particular nitrite and nitrate radical chemistry, have been studied far less. These condensed-phase free-radical reactions may be relevant in fog and cloud water in polluted areas, in urban aerosols with low pH, in water treatment using advanced oxidation processes such as electron beam (e-beam) irradiation, and in nuclear waste treatment applications. This study discusses research toward an improved understanding of nitration of aromatic compounds in the condensed phase under conditions conducive to free-radical formation. The results are of benefit in several areas of environmental chemistry, in particular nuclear waste treatment applications. The nitration reactions of anisole and toluene as model compounds were investigated in γ-irradiated acidic nitrate, neutral nitrate, and neutral nitrite solutions. Cs-7SB, 1-(2,2,3,3,-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, is used as a solvent modifier in the fission product extraction (FPEX) formulation for the extraction of Cs and Sr from dissolved nuclear fuel. The formulation also contains the ligands calix(4)arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6) for Cs extraction and 4,4(prime),(5(prime))-di-(t-butyldicyclohexano)-18-crown-6 (DtBuCH18C6) for Sr extraction, all in Isopar L, a branched-chain alkane diluent. FPEX solvent has favorable extraction efficiency for Cs and Sr from acidic solution and was investigated at the Idaho National Laboratory (INL) for changes in extraction efficiency after γ-irradiation. Extraction efficiency decreased after irradiation. The decrease in solvent extraction efficiency was identical for Cs and Sr, even though they are complexed by different ligands. This suggests that

Vibronic Spectroscopy of the Phenylcyanomethyl Radical

Science.gov (United States)

Mehta, Deepali N.; Kidwell, Nathanael M.; Zwier, Timothy S.

2011-06-01

Resonance stabilized radicals (RSRs) are thought to be key intermediates in the formation of larger molecules in planetary atmospheres. Given the nitrogen-rich atmosphere of Titan, and the prevalence of nitriles there, it is likely that nitrile and isonitrile RSRs could be especially important in pathways leading to the formation of more complex nitrogen-containing compounds and the aerosols ("tholins") that are ultimately produced. In this talk, the results of a gas phase, jet-cooled vibronic spectroscopy study of the phenylcyanomethyl radical (C_6H_5.{C}HCN), the nitrogen-containing analog of the 1-phenylpropargyl radical, will be presented. A resonant two color photon ionization spectrum over the range 21,350-22,200 Cm-1 (450.0-468.0 nm) has been recorded, and the D_0-D_1 origin band has been tentatively identified at 21,400 Cm-1. Studies identifying the ionization threshold, and characterizing the vibronic structure will also be presented. An analogous study of the phenylisocyanomethyl radical, C_6H_5.{C}HNC, is currently being pursued for comparison with that of phenylcyanomethyl radical.

Introducing Stable Radicals into Molecular Machines.

Science.gov (United States)

Wang, Yuping; Frasconi, Marco; Stoddart, J Fraser

2017-09-27

Ever since their discovery, stable organic radicals have received considerable attention from chemists because of their unique optical, electronic, and magnetic properties. Currently, one of the most appealing challenges for the chemical community is to develop sophisticated artificial molecular machines that can do work by consuming external energy, after the manner of motor proteins. In this context, radical-pairing interactions are important in addressing the challenge: they not only provide supramolecular assistance in the synthesis of molecular machines but also open the door to developing multifunctional systems relying on the various properties of the radical species. In this Outlook, by taking the radical cationic state of 1,1'-dialkyl-4,4'-bipyridinium (BIPY •+ ) as an example, we highlight our research on the art and science of introducing radical-pairing interactions into functional systems, from prototypical molecular switches to complex molecular machines, followed by a discussion of the (i) limitations of the current systems and (ii) future research directions for designing BIPY •+ -based molecular machines with useful functions.

Towards Integration of Ecosystem and Human Health: A Novel Conceptual Framework to Operationalise Ecological Public Health and to Incorporate Distal and Proximal Effects of Climate Change

Science.gov (United States)

Reis, S.; Fleming, L. E.; Beck, S.; Austen, M.; Morris, G.; White, M.; Taylor, T. J.; Orr, N.; Osborne, N. J.; Depledge, M.

2014-12-01

Conceptual models for problem framing in environmental (EIA) and health impact assessment (HIA) share similar concepts, but differ in their scientific or policy focus, methodologies and underlying causal chains, and the degree of complexity and scope. The Driver-Pressure-State-Impact-Response (DPSIR) framework used by the European Environment Agency, the OECD and others and the Integrated Science for Society and the Environment (ISSE) frameworks are widely applied in policy appraisal and impact assessments. While DPSIR is applied across different policy domains, the ISSE framework is used in Ecosystem Services assessments. The modified Driver-Pressure-State-Exposure-Effect-Action (DPSEEA) model extends DPSIR by separating exposure from effect, adding context as a modifier of effect, and susceptibility to exposures due to socio-economic, demographic or other determinants. While continuously evolving, the application of conceptual frameworks in policy appraisals mainly occurs within established discipline boundaries. However, drivers and environmental states, as well as policy measures and actions, affect both human and ecosystem receptors. Furthermore, unintended consequences of policy actions are seldom constrained within discipline or policy silos. Thus, an integrated conceptual model is needed, accounting for the full causal chain affecting human and ecosystem health in any assessment. We propose a novel model integrating HIA methods and ecosystem services in an attempt to operationalise the emerging concept of "Ecological Public Health." The conceptual approach of the ecosystem-enriched DPSEEA model ("eDPSEEA") has stimulated wide-spread debates and feedback. We will present eDPSEEA as a stakeholder engagement process and a conceptual model, using illustrative case studies of climate change as a starting point, not a complete solution, for the integration of human and ecosystem health impact assessment as a key challenge in a rapidly changing world. Rayner G and

Free radical scavenging and COX-2 inhibition by simple colon metabolites of polyphenols: A theoretical approach.

Science.gov (United States)

Amić, Ana; Marković, Zoran; Marković, Jasmina M Dimitrić; Jeremić, Svetlana; Lučić, Bono; Amić, Dragan

2016-12-01

Free radical scavenging and inhibitory potency against cyclooxygenase-2 (COX-2) by two abundant colon metabolites of polyphenols, i.e., 3-hydroxyphenylacetic acid (3-HPAA) and 4-hydroxyphenylpropionic acid (4-HPPA) were theoretically studied. Different free radical scavenging mechanisms are investigated in water and pentyl ethanoate as a solvent. By considering electronic properties of scavenged free radicals, hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms are found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of free radicals indicates 3-HPAA and 4-HPPA as potent scavengers. Their reactivity toward free radicals was predicted to decrease as follows: hydroxyl>alkoxyls>phenoxyl≈peroxyls>superoxide. Shown free radical scavenging potency of 3-HPAA and 4-HPPA along with their high μM concentration produced by microbial colon degradation of polyphenols could enable at least in situ inactivation of free radicals. Docking analysis with structural forms of 3-HPAA and 4-HPPA indicates dianionic ligands as potent inhibitors of COX-2, an inducible enzyme involved in colon carcinogenesis. Obtained results suggest that suppressing levels of free radicals and COX-2 could be achieved by 3-HPAA and 4-HPPA indicating that these compounds may contribute to reduced risk of colon cancer development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Some reactions of oxidizing radicals with enzymes in aqueous solution

International Nuclear Information System (INIS)

Cundall, R.B.; Bisby, R.H.; Hoe, S.T.; Sims, H.E.; Anderson, R.F.

1979-01-01

A range of oxidizing radicals including some inorganic radical anions and the superoxide radical, can be generated by radiolysis of aqueous solutions. These radicals are more selective in their reactions with amino acids than the hydroxyl radical. Factors controlling the apparent reactivity of radical anions with proteins, such as free radical equilibria and ion-binding, are described. The superoxide radical inactivates papain by reaction with the cysteine residue. This reaction has been studied in solutions subjected to radiations of varying linear energy transfer. (Auth.)

Toll-Like Receptor-Mediated Free Radical Generation in Clonorchis sinensis Excretory-Secretory Product-Treated Cholangiocarcinoma Cells.

Science.gov (United States)

Bahk, Young Yil; Pak, Jhang Ho

2016-10-01

Clonorchiasis, caused by direct contact with Clonorchis sinensis worms and their excretory-secretory products (ESPs), is associated with chronic inflammation, malignant changes in bile ducts, and even cholangiocarcinogenesis. Our previous report revealed that intracellular free radicals enzymatically generated by C. sinensis ESPs cause NF-κB-mediated inflammation in human cholangiocarcinoma cells (HuCCT1). Therefore, the present study was conducted to examine the role of upstream Toll-like receptors (TLRs) on the initial host innate immune responses to infection. We found that treatment of HuCCT1 cells with native ESPs induced changes in TLR mRNA levels in a time-dependent manner, concomitant with the generation of free radicals. ESP-mediated free radical generation was markedly attenuated by preincubation of the cells with TLR1-4-neutralizing antibodies, indicating that at least TLR1 through 4 participate in stimulation of the host innate immune responses. These findings indicate that free radicals triggered by ESPs are critically involved in TLR signal transduction. Continuous signaling by this pathway may function in initiating C. sinensis infection-associated inflammation cascades, a detrimental event leading to progression to more severe hepatobiliary diseases.

Long-lived gas-phase radicals from combustion

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Takashi; Furusawa, Koji; Amano, Toshiji; Okubo, Yoichi; Tsuchiya, Jun' ichi; Yoshizawa, Fujiroku; Akutsu, Yoshiaki; Tamura, Masamitsu; Yoshida, Tadao (Univ. of Tokyo (Japan))

1989-04-20

On indoor air pollution or fire, it is feared that the gas-phase radicals from the combustion of inflammables or fuel seriously exert an influence on the organisms as harmful matter. The gas-phase radicals were studied using the electron spin resonance (ESR) spin-trapping technique. For the spin trap solution, 0.1 mol solution of {alpha}-phenyl-N-t-butylnitron in benzene was used. As a result, apparently long-lived and highly reactive oxygen-centered radicals were detected in the smoke from polyethylene, polypropylene, polystyrene, polymethylmethacrylate, cellulose, kerosene, benzene, acetone, methanol and butylalcohol. It is suggested that the production mechanism for the radicals should be different from olefin-NOx-air system reaction, which is considered for the radicals from cigarette smoke. 11 refs., 6 figs., 2 tabs.

Logistics and Transport - a conceptual model

DEFF Research Database (Denmark)

Jespersen, Per Homann; Drewes, Lise

2004-01-01

This paper describes how the freight transport sector is influenced by logistical principles of production and distribution. It introduces new ways of understanding freight transport as an integrated part of the changing trends of mobility. By introducing a conceptual model for understanding...... the interaction between logistics and transport, it points at ways to over-come inherent methodological difficulties when studying this relation...

[Research progress on free radicals in human body].

Science.gov (United States)

Wang, Q B; Xu, F P; Wei, C X; Peng, J; Dong, X D

2016-08-10

Free radicals are the intermediates of metabolism, widely exist in the human bodies. Under normal circumstances, the free radicals play an important role in the metabolic process on human body, cell signal pathway, gene regulation, induction of cell proliferation and apoptosis, so as to maintain the normal growth and development of human body and to inhibit the growth of bacteria, virus and cancer. However, when organic lesion occurs affected by external factors or when equilibrium of the free radicals is tipped in the human body, the free radicals will respond integratedly with lipids, protein or nucleic acid which may jeopardize the health of human bodies. This paper summarizes the research progress of the free radicals conducted in recent years, in relations to the perspective of the types, origins, test methods of the free radicals and their relationship with human's health. In addition, the possible mechanisms of environmental pollutants (such as polycyclic aromatic hydrocarbons) mediating oxidative stress and free radicals scavenging in the body were also summarized.

Voting for a change : The democratic lure of populist radical right parties in voting behavior

NARCIS (Netherlands)

Immerzeel, T.

2015-01-01

With the entrance and growing popularity of populist radical right parties (PRRs) in Western and Eastern European democracies in the 1980s, 1990s and 2000s, the scientific and public debate has recently focused on the ‘threatening’ and ‘corrective’ consequences of the PRR for contemporary

Free radical activity during development of insulin-dependent diabetes mellitus in the rat

Energy Technology Data Exchange (ETDEWEB)

Pitkaenen, O.M.; Akerblom, H.K.; Sariola, H.; Andersson, S.M. (Univ. of Helsinki (Finland)); Martin, J.M. (Hospital for Sick Children, Toronto, Ontario (Canada)); Hallman, M. (Univ. of California, Irvine (United States))

1991-01-01

Free radical-induced lipid peroxidation was quantified by measuring expired pentane from diabetic prone BB Wistar rats of 45-90 d of age. Insulin-dependent diabetes mellitus was manifest at the age of 71 {plus minus} 8 d. Expired pentane increased from 2.1 {plus minus} 0.7 to 5.0 {plus minus}3.0 pmol/100g/min (p <0.01) at manifestation of the disease and remained high throughout the test period. In healthy age-matched control rats it persisted low. In rats made diabetic with streptozotocin, expired pentane remained low. The changes in expired pentane suggest that the development of endogenous insulin-dependent diabetes mellitus in BB rats is associated with increased free radical activity. This is not due to hyperglycemia or ketosis per se, and reflects a fundamental difference in the free radical activity between the spontaneously diabetic BB rats and the disease produced by streptozotocin. Development of spontaneous insulin-dependent diabetes in BB rats is associated with increased free radical activity that persists after the manifestation of the disease.

Zwitterion radicals and anion radicals from electron transfer and solvent condensation with the fingerprint developing agent ninhydrin.

Science.gov (United States)

Schertz, T D; Reiter, R C; Stevenson, C D

2001-11-16

Ninhydrin (the fingerprint developing agent) spontaneously dehydrates in liquid ammonia and in hexamethylphosphoramide (HMPA) to form indantrione, which has a sufficiently large solution electron affinity to extract an electron from the solvent (HMPA) to produce the indantrione anion radical. In liquid NH(3), the presence of trace amounts of amide ion causes the spontaneous formation of an anion radical condensation product, wherein the no. 2 carbon (originally a carbonyl carbon) becomes substituted with -NH(2) and -OH groups. In HMPA, the indantrione anion radical spontaneously forms condensation products with the HMPA to produce a variety of zwitterionic radicals, wherein the no. 2 carbon becomes directly attached to a nitrogen of the HMPA. The mechanisms for the formation of the zwitterionic paramagnetic condensation products are analogous to that observed in the reaction of ninhydrin with amino acids to yield Ruhemann's Purple, the contrast product in fingerprint development. The formation of anion and zwitterionic radical condensation products from ninhydrin and nitrogen-containing solvents may represent an example of a host of analogous polyketone-solvent reactions.

Characteristics of ultraviolet light and radicals formed by pulsed discharge in water

Science.gov (United States)

Sun, Bing; Kunitomo, Shinta; Igarashi, Chiaki

2006-09-01

In this investigation, the ultraviolet light characteristics and OH radical properties produced by a pulsed discharge in water were studied. For the plate-rod reactor, it was found that the ultraviolet light energy has a 3.2% total energy injected into the reactor. The ultraviolet light changed with the peak voltage and electrode distance. UV characteristics in tap water and the distilled water are given. The intensity of the OH radicals was the highest for the 40 mm electrode distance reactor. In addition, the properties of hydrogen peroxide and ozone were also studied under arc discharge conditions. It was found that the OH radicals were in the ground state and the excited state when a pulsed arc discharge was used. The ozone was produced by the arc discharge even if the oxygen gas is not bubbled into the reactor. The ozone concentration produces a maximum value with treatment time.

Characteristics of ultraviolet light and radicals formed by pulsed discharge in water

Energy Technology Data Exchange (ETDEWEB)

Sun Bing [Dalian Maritime University, College of Environment, 1st Linghai Road, Dalian (China); Kunitomo, Shinta [Ebara Corporation, 1-6-27, Konan, Minato-ku 108-8480 (Japan); Igarashi, Chiaki [Ebara Research Co. Ltd, 2-1, Honfujisawa 4-chome, Fujisawa 251-8502 (Japan)

2006-09-07

In this investigation, the ultraviolet light characteristics and OH radical properties produced by a pulsed discharge in water were studied. For the plate-rod reactor, it was found that the ultraviolet light energy has a 3.2% total energy injected into the reactor. The ultraviolet light changed with the peak voltage and electrode distance. UV characteristics in tap water and the distilled water are given. The intensity of the OH radicals was the highest for the 40 mm electrode distance reactor. In addition, the properties of hydrogen peroxide and ozone were also studied under arc discharge conditions. It was found that the OH radicals were in the ground state and the excited state when a pulsed arc discharge was used. The ozone was produced by the arc discharge even if the oxygen gas is not bubbled into the reactor. The ozone concentration produces a maximum value with treatment time.

Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy

International Nuclear Information System (INIS)

Mani, Tomoyasu; Brookhaven National Laboratory; Grills, David C.

2017-01-01

Delocalization of charges is one of the factors controlling charge transport in conjugated molecules. It is considered to play an important role in the performance of a wide range of molecular technologies, including organic solar cells and organic electronics. Dimerization reactions are well-suited as a model to investigate intermolecular spatial delocalization of charges. And while dimerization reactions of radical cations are well investigated, studies on radical anions are still scarce. Upon dimerization of radical anions with neutral counterparts, an electron is considered to delocalize over the two molecules. By using time-resolved infrared (TRIR) detection coupled with pulse radiolysis, we show that radical anions of 4-n-hexyl-4'-cyanobiphenyl (6CB) undergo such dimerization reactions, with an electron equally delocalized over the two molecules. We have recently demonstrated that nitrile ν(C≡N) vibrations respond to the degree of electron localization of nitrile-substituted anions: we can quantify the changes in the electronic charges from the neutral to the anion states in the nitriles by monitoring the ν(C≡N) IR shifts. In the first part of this article, we show that the sensitivity of the ν(C≡N) IR shifts does not depend on solvent polarity. In the second part, we describe how probing the shifts of the nitrile IR vibrational band unambiguously confirms the formation of dimer radical anions, with K dim = 3 × 10 4 M –1 . IR findings are corroborated by electronic absorption spectroscopy and electronic structure calculations. We find that the presence of a hexyl chain and the formation of π–π interactions are both crucial for dimerization of radical anions of 6CB with neutral 6CB. Our study provides clear evidence of spatial delocalization of electrons over two molecular fragments.

Free radical scavenging injectable hydrogels for regenerative therapy

Energy Technology Data Exchange (ETDEWEB)

Komeri, Remya [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India); Thankam, Finosh Gnanaprakasam [Dept. of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha NE68178 (United States); Muthu, Jayabalan, E-mail: mjayabalan52@gmail.com [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India)

2017-02-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07 kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. - Graphical abstract: Injectable hydrogel with inherent free radical scavenging property for regenerative tissue engineering application. - Highlights: • Novel injectable hydrogel (PEAX-P) is prepared using D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer

Free radical scavenging injectable hydrogels for regenerative therapy

International Nuclear Information System (INIS)

Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

2017-01-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07 kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. - Graphical abstract: Injectable hydrogel with inherent free radical scavenging property for regenerative tissue engineering application. - Highlights: • Novel injectable hydrogel (PEAX-P) is prepared using D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer

Radical Transversal Lightlike Submanifolds of Indefinite Para-Sasakian Manifolds

OpenAIRE

Shukla S.S.; Yadav Akhilesh

2014-01-01

In this paper, we study radical transversal lightlike submanifolds and screen slant radical transversal lightlike submanifolds of indefinite para-Sasakian manifolds giving some non-trivial examples of these submanifolds. Integrability conditions of distributions D and RadTM on radical transversal lightlike submanifolds and screen slant radical transversal lightlike submanifolds of indefinite para-Sasakian manifolds, have been obtained. We also study totally contact umbilical radical transvers...

Structure and reactivity of the N-acetyl-cysteine radical cation and anion: does radical migration occur?

NARCIS (Netherlands)

Osburn, S.; Berden, G.; Oomens, J.; O'Hair, R.A.J.; Ryzhov, V.

2011-01-01

The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of

Structure and Reactivity of the N-Acetyl-Cysteine Radical Cation and Anion: Does Radical Migration Occur?

NARCIS (Netherlands)

Osburn, S.; G. Berden,; Oomens, J.; O' Hair, R. A. J.; Ryzhov, V.

2011-01-01

The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of

Cation radicals of xanthophylls.

Science.gov (United States)

Galinato, Mary Grace I; Niedzwiedzki, Dariusz; Deal, Cailin; Birge, Robert R; Frank, Harry A

2007-10-01

Carotenes and xanthophylls are well known to act as electron donors in redox processes. This ability is thought to be associated with the inhibition of oxidative reactions in reaction centers and light-harvesting pigment-protein complexes of photosystem II (PSII). In this work, cation radicals of neoxanthin, violaxanthin, lutein, zeaxanthin, beta-cryptoxanthin, beta-carotene, and lycopene were generated in solution using ferric chloride as an oxidant and then studied by absorption spectroscopy. The investigation provides a view toward understanding the molecular features that determine the spectral properties of cation radicals of carotenoids. The absorption spectral data reveal a shift to longer wavelength with increasing pi-chain length. However, zeaxanthin and beta-cryptoxanthin exhibit cation radical spectra blue-shifted compared to that of beta-carotene, despite all of these molecules having 11 conjugated carbon-carbon double bonds. CIS molecular orbital theory quantum computations interpret this effect as due to the hydroxyl groups in the terminal rings selectively stabilizing the highest occupied molecular orbitals of preferentially populated s-trans-isomers. The data are expected to be useful in the analysis of spectral results from PSII pigment-protein complexes seeking to understand the role of carotene and xanthophyll cation radicals in regulating excited state energy flow, in protecting PSII reaction centers against photoinhibition, and in dissipating excess light energy absorbed by photosynthetic organisms but not used for photosynthesis.

A Conceptual Mirror

DEFF Research Database (Denmark)

Badie, Farshad

2017-01-01

The multilevel interactions between a mentor and her/his learner could exchange various conceptions between them that are supported by their own conceptualisations. Producing the own realisation of a world and developing it in the context of interactions could be said to be the most valuable prod...... will analyse the logical dependencies between learner and men- tor and will check their reflectional symmetrical relationship in a conceptual mirror. The conceptual mirror is a phenomenon that represents the meeting point of the mentor’s and the learner’s conceptual knowledge....

Understanding general practice: a conceptual framework developed from case studies in the UK NHS.

Science.gov (United States)

Checkland, Kath

2007-01-01

General practice in the UK is undergoing a period of rapid and profound change. Traditionally, research into the effects of change on general practice has tended to regard GPs as individuals or as members of a professional group. To understand the impact of change, general practices should also be considered as organisations. To use the organisational studies literature to build a conceptual framework of general practice organisations, and to test and develop this empirically using case studies of change in practice. This study used the implementation of National Service Frameworks (NSFs) and the new General Medical Services (GMS) contract as incidents of change. In-depth, qualitative case studies. The design was iterative: each case study was followed by a review of the theoretical ideas. The final conceptual framework was the result of the dynamic interplay between theory and empirical evidence. Five general practices in England, selected using purposeful sampling. Semi-structured interviews with all clinical and managerial personnel in each practice, participant and nonparticipant observation, and examination of documents. A conceptual framework was developed that can be used to understand how and why practices respond to change. This framework enabled understanding of observed reactions to the introduction of NSFs and the new GMS contract. Important factors for generating responses to change included the story that the practice members told about their practice, beliefs about what counted as legitimate work, the role played by the manager, and previous experiences of change. Viewing general practices as small organisations has generated insights into factors that influence responses to change. Change tends to occur from the bottom up and is determined by beliefs about organisational reality. The conceptual framework suggests some questions that can be asked of practices to explain this internal reality.