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Volumetric Flank Wear Characterization For Titanium Milling Insert Tools, Uli Burger, Mathew Kuttolamadom, April Bryan, Laine Mears, Thomas Kurfess Oct 2009

Volumetric Flank Wear Characterization For Titanium Milling Insert Tools, Uli Burger, Mathew Kuttolamadom, April Bryan, Laine Mears, Thomas Kurfess

Publications

Machining wear models are useful for the prediction of tool life and the estimation of machining productivity. Existing wear models relate the cutting parameters of feed, speed, and depth of cut to tool wear. The tool wear is often reported as changes in flank width or crater depth. However, these one-dimensional wear measurements do not fully characterize the tool condition when tools wear by other types of wear such as notching, chipping, and adhesion. This is especially true when machining difficult-to-machine materials such as titanium. This paper proposes another approach for characterizing tool wear. It is based on taking measurements …

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The Tiger Vol. 103 Issue 16 2009-09-18, Clemson University Sep 2009

The Tiger Vol. 103 Issue 16 2009-09-18, Clemson University

Tiger Newspapers

No abstract provided.

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The Tiger Vol. 103 Issue 14 2009-09-04, Clemson University Sep 2009

The Tiger Vol. 103 Issue 14 2009-09-04, Clemson University

Tiger Newspapers

No abstract provided.

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Update Sequence Stability In Graph Dynamical Systems, Matthew Macauley, Henning S. Mortveit Sep 2009

Update Sequence Stability In Graph Dynamical Systems, Matthew Macauley, Henning S. Mortveit

Publications

In this article, we study finite dynamical systems defined over graphs, where the functions are applied asynchronously. Our goal is to quantify and understand stability of the dynamics with respect to the update sequence, and to relate this to structural properties of the graph. We introduce and analyze three different notions of update sequence stability, each capturing different aspects of the dynamics. When compared to each other, these stability concepts yield vastly different conclusions regarding the relationship between stability and graph structure, painting a more complete picture of update sequence stability.

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Accelerating Sift On Parallel Architectures, Amy Apon, Seth Warn, Wesley Emeneker, Jackson Cothren Sep 2009

Accelerating Sift On Parallel Architectures, Amy Apon, Seth Warn, Wesley Emeneker, Jackson Cothren

Publications

SIFT is a widely-used algorithm that extracts features from images; using it to extract information from hundreds of terabytes of aerial and satellite photographs requires parallelization in order to be feasible. We explore accelerating an existing serial SIFT implementation with OpenMP parallelization and GPU execution.

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Using Population Synthesis Of Massive Stars To Study The Interstellar Medium Near Ob Associations, R. Voss, R. Diehl, Dieter H. Hartmann, M. Cerviño, J. S. Vink, G. Meynet, M. Limongi, A. Chieffi Sep 2009

Using Population Synthesis Of Massive Stars To Study The Interstellar Medium Near Ob Associations, R. Voss, R. Diehl, Dieter H. Hartmann, M. Cerviño, J. S. Vink, G. Meynet, M. Limongi, A. Chieffi

Publications

Aims. We study the massive stars in OB associations and their surrounding interstellar medium environment, using a population synthesis code. Methods. We developed a new population synthesis code for groups of massive stars, where we model the emission of different forms of energy and matter from the stars of the association. In particular, the ejection of the two radioactive isotopes 26Al and 60Fe is followed, as well as the emission of hydrogen ionizing photons, and the kinetic energy of the stellar winds and supernova explosions. We investigate various alternative astrophysical inputs and the resulting output sensitivities, especially effects due to …

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Weibel Instability And Associated Strong Fields In A Fully 3d Simulation Of A Relativistic Shock, K.-I. Nishikawa, J. Niemiec, P. E. Hardee, M. Medvedev, H. Sol, Y. Mizuno, B. Zhang, M. Pohl, M. Oka, Dieter H. Hartmann Aug 2009

Weibel Instability And Associated Strong Fields In A Fully 3d Simulation Of A Relativistic Shock, K.-I. Nishikawa, J. Niemiec, P. E. Hardee, M. Medvedev, H. Sol, Y. Mizuno, B. Zhang, M. Pohl, M. Oka, Dieter H. Hartmann

Publications

Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) excited in collision-less shocks are responsible for particle (electron, positron, and ion) acceleration. Using a new 3-D relativistic particle-in-cell code, we have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. The simulation has been performed using a long simulation system in order to study the nonlinear stages of the Weibel instability, the particle acceleration mechanism, and the shock structure. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic …

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Clemson Commencement Program, August 2009, Clemson University Aug 2009

Clemson Commencement Program, August 2009, Clemson University

Clemson Commencement Programs

No abstract provided.

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Tracing The Inner Edge Of The Disk Around Hd 100546 With Rovibrational Co Emission Lines, Sean D. Brittain, Joan R. Najita, John S. Carr Aug 2009

Tracing The Inner Edge Of The Disk Around Hd 100546 With Rovibrational Co Emission Lines, Sean D. Brittain, Joan R. Najita, John S. Carr

Publications

In this paper we present high-resolution 4.7 μm spectra of the isolated Herbig Be star HD 100546. HD 100546 has been the subject of intense scrutiny because it is a young nearby star with a transitional disk. We observe the Δv = 1 rovibrational CO transitions in order to clarify the distribution of warm gas in the inner disk. Modeling of the CO spectrum indicates that the gas is vibrationally excited by collisions and UV fluorescence. The observed emission extends from 13 to 100 AU. The inner edge of the molecular gas emission is consistent with the inner edge of …

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2009 Summary Report On Institutional Effectiveness, Clemson University Aug 2009

2009 Summary Report On Institutional Effectiveness, Clemson University

Institutional Effectiveness Reports

No abstract provided.

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Social Support And Persistence Among University Transfer Students Attending A Community College: A Grounded Theory Study, Stanley Burdette Aug 2009

Social Support And Persistence Among University Transfer Students Attending A Community College: A Grounded Theory Study, Stanley Burdette

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This study explored the role of social support in relation to the persistence of community college students enrolled in a university transfer program at a single institution. Student persistence rates in community colleges are low in comparison to other sectors of higher education. To explain community college student persistence, past researchers relied on theories of student retention that were developed from data collected in traditional four-year colleges and universities. Although the dominant theories of student retention emphasized social integration and involvement, the role of social support as related to persistence in community colleges was not adequately explored. The purpose of …

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Change-Point Analysis: Asymptotic Theory And Applications, Michael Robbins Aug 2009

Change-Point Analysis: Asymptotic Theory And Applications, Michael Robbins

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The problem of undocumented change-points in data sets appears in many areas of science. Mathematical fundamentals of asymptotic methods used in change-point analysis are discussed, and several important maximally selected change-point statistics are introduced. First, the likelihood ratio method is applied to abstract data models within the setting of precipitation series. Basic inference as to the legitimacy and effectiveness of asymptotic methods at detecting undocumented change-points is provided. Next, maximally selected chi-square statistics are discussed in detail and applied to data on tropical cyclone behavior, where a widely available and widely analyzed data set on Atlantic basin cyclones is studied. …

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Exploring Teacher Perceptions Of Influential Facilitators Of Elementary Mathematics Professional Development: A Mixed Methods Investigation, Sandra Linder Aug 2009

Exploring Teacher Perceptions Of Influential Facilitators Of Elementary Mathematics Professional Development: A Mixed Methods Investigation, Sandra Linder

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This dissertation examines the role of the facilitator in elementary mathematics professional development. An exploratory sequential mixed methods design was utilized to answer the central research question: How do United States elementary school teachers perceive an influential facilitator of elementary mathematics professional development (EMPD)? Phase one of this study explored teacher perceptions through a phenomenological design, which informed the second phase of the study, the implementation of a survey instrument to elementary school mathematics teachers on a larger scale. This dissertation is divided into six chapters. Chapter One presents a rationale for examining the role of the facilitator in professional …

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Multiobjective Optimization For Complex Systems, Melissa Gardenghi Aug 2009

Multiobjective Optimization For Complex Systems, Melissa Gardenghi

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Complex systems are becoming more and more apparent in a variety of disciplines, making solution methods for these systems valuable tools. The solution of complex systems requires two significant skills. The first challenge of developing mathematical models for these systems is followed by the difficulty of solving these models to produce preferred solutions for the overall systems. Both issues are addressed by this research.
This study of complex systems focuses on two distinct aspects. First, models of complex systems with multiobjective formulations and a variety of structures are proposed. Using multiobjective optimization theory, relationships between the efficient solutions of the …

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Synthesis Of Complex Fluorides For Optical Applications, Seth Stepleton Aug 2009

Synthesis Of Complex Fluorides For Optical Applications, Seth Stepleton

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Large single crystals of alkali metal fluorides are desirable for many reasons. Fluoride laser crystals have a wide transmission range and on account of their low phonon energies, many efficient laser emissions have been obtained from 285 nm to 4.34 µm.1,2 Inorganic fluoride single crystals feature large bandgaps, very wide optical transmittance ranges from vacuum-ultraviolet (VUV) to mid-IR wavelength regions, lower refractive indices than those of oxides, and typically lower phonon energies (which drastically reduce multiphonon relaxation rates of rare earth ions).3
The main goal of this work was to investigate the hydrothermal synthesis of alkali metal fluorides. Melt techniques …

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Motion Segmentation From Clustering Of Sparse Point Features Using Spatially Constrained Mixture Models, Shrinivas Pundlik Aug 2009

Motion Segmentation From Clustering Of Sparse Point Features Using Spatially Constrained Mixture Models, Shrinivas Pundlik

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Motion is one of the strongest cues available for segmentation. While motion segmentation finds wide ranging applications in object detection, tracking, surveillance, robotics, image and video compression, scene reconstruction, video editing, and so on, it faces various challenges such as accurate motion recovery from noisy data, varying complexity of the models required to describe the computed image motion, the dynamic nature of the scene that may include a large number of independently moving objects undergoing occlusions, and the need to make high-level decisions while dealing with long image sequences. Keeping the sparse point features as the pivotal point, this thesis …

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Hydrothermal Crystal Growth Of Tetravalent And Pentavalent Metal Oxides, James Mann Aug 2009

Hydrothermal Crystal Growth Of Tetravalent And Pentavalent Metal Oxides, James Mann

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Over the past two hundred years synthetic growth of crystals has become vital to the technological advancement of our society. A variety of crystal growth techniques have been developed during this time, with each having its own nuances. These differences have enabled the growth of a wide spectrum of crystalline materials that can be used for many applications which include solid state lasers, semiconductors, and communication devices. Despite these techniques there are entire classes of materials which have thus far proved quite difficult to prepare as single crystals. In particular, crystal growth of the tetravalent and pentavalent metal oxides has …

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A Study Of Client-Based Caching For Parallel I/O, Bradley Settlemyer Aug 2009

A Study Of Client-Based Caching For Parallel I/O, Bradley Settlemyer

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The trend in parallel computing toward large-scale cluster computers running thousands of cooperating processes per application has led to an I/O bottleneck that has only gotten more severe as the the number of processing cores per CPU has increased. Current parallel file systems are able to provide high bandwidth file access for large contiguous file region accesses; however, applications repeatedly accessing small file regions on unaligned file region boundaries continue to experience poor I/O throughput due to the high overhead associated with accessing parallel file system data.
In this dissertation we demonstrate how client-side file data caching can improve parallel …

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Variations On Graph Products And Vertex Partitions, Jobby Jacob Aug 2009

Variations On Graph Products And Vertex Partitions, Jobby Jacob

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In this thesis we investigate two graph products called double vertex graphs and complete double vertex graphs, and two vertex partitions called dominator partitions and rankings.
We introduce a new graph product called the complete double vertex graph and study its properties. The complete double vertex graph is a natural extension of the Cartesian product and a generalization of the double vertex graph.
We establish many properties of complete double vertex graphs, including results involving the chromatic number of a complete double vertex graph and the characterization of planar complete double vertex graphs. We also investigate the important problem of …

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Integer-Valued Time Series And Renewal Processes, Yunwei Cui Aug 2009

Integer-Valued Time Series And Renewal Processes, Yunwei Cui

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This research proposes a new but simple model for stationary time series of integer counts. Previous work in the area has focused on mixture and thinning methods and links to classical time series autoregressive moving-average difference equations; in contrast, our methods use a renewal process to generate a correlated sequence of Bernoulli trials. By superpositioning independent copies of such processes, stationary series with binomial, Poisson, geometric, or any other discrete marginal distribution can be readily constructed. The model class proposed is parsimonious, non-Markov, and readily generates series with either short or long memory autocovariances. The model can be fitted with …

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Student Perceptions Of Reading Motivation In A Voluntary Summer Reading Program: A Mixed Methods Dissertation, Julie Mcgaha Aug 2009

Student Perceptions Of Reading Motivation In A Voluntary Summer Reading Program: A Mixed Methods Dissertation, Julie Mcgaha

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How might a voluntary, high school summer reading program affect students' literacy motivation? A sequential exploratory mixed methods line of research attempted to answer this question. In study 1, after completing a summer reading program, 900 students from the 10th, 11th, and 12th grades provided written responses to the open-ended question, 'What was the best thing about the summer reading program?' The researchers analyzed their responses with a phenomenological technique adapted from Moustakas (1994), yielding 11 motivational themes. In study 2, those themes guided the creation of a survey instrument, which then was administered to a different sample of 1600 …

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Exploring Different Instructional Designs Of A Screen-Captured Video Lesson: A Mixed Methods Study Of Transfer Of Learnng, Ryan Visser Aug 2009

Exploring Different Instructional Designs Of A Screen-Captured Video Lesson: A Mixed Methods Study Of Transfer Of Learnng, Ryan Visser

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Digital instruction, whether in the form of training delivered on CD/DVD-ROMs or online courses delivered via the Internet is being used in all levels of education. It can, after all, increase student achievement if designed properly (Moersch, 1999). Many established instructional technologies (e.g. Microsoft PowerPoint®) have been researched to determine effective and ineffective instructional designs. However, newer technologies such as screen-captured videos, have not.
Because the research of newer, multimedia instructional technology is 'in its infancy' (Mayer, 2001, p.194), a timely challenge for instructional technologists is to determine how to design and research these technologies. Theoretical frameworks on which to …

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The Reality Of The Wolf 630 Moving Group, Eric Bubar Aug 2009

The Reality Of The Wolf 630 Moving Group, Eric Bubar

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The concept of relic kinematic assemblages from dispersed stellar clusters has
remained contentious since Eggen's initial formulation of moving groups in the
1960's. However, the availability of high quality parallaxes from the Hipparcos
space astrometry mission has resulted in distance measurements for thousands of
nearby, seemingly isolated stars. With these newly determined distances, a
high resolution spectroscopic abundance analysis can be brought to bear on many of the
alleged members of these relic associations. If a structure is a relic of
an open cluster, the members can be expected to be monolithic in age and abundance
inasmuch as homogeneity is …

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Improved Thermoelectric Performance Of P-Type Polycrystalline Bi2te3 Via Hydrothermal Treatment With Alkali Metal Salts, Zhe Su Aug 2009

Improved Thermoelectric Performance Of P-Type Polycrystalline Bi2te3 Via Hydrothermal Treatment With Alkali Metal Salts, Zhe Su

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The field of thermoelectric research has attracted a lot of interest in hope of helping address the energy crisis. In recent years, low-dimensional thermoelectric materials have been found promising and thus become a popular school of thought. However, the high complexity and cost for fabricating low-dimensional materials give rise to the attempt to further improve conventional bulk polycrystalline materials. Polycrystals are featured by numerous grain boundaries that can scatter heat-carrying phonons to significantly reduce the thermal conductivity κ whereas at the same time can unfortunately deteriorate the electrical resistivity ρ. Aiming at the dualism of the grain boundaries in determining …

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Creation Of Defined Single Cell Resolution Neuronal Circuits On Microelectrode Arrays, Russell Pirlo Aug 2009

Creation Of Defined Single Cell Resolution Neuronal Circuits On Microelectrode Arrays, Russell Pirlo

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The way cell-cell organization of neuronal networks influences activity and facilitates function is not well understood. Microelectrode arrays (MEAs) and advancing cell patterning technologies have enabled access to and control of in vitro neuronal networks spawning much new research in neuroscience and neuroengineering. We propose that small, simple networks of neurons with defined circuitry may serve as valuable research models where every connection can be analyzed, controlled and manipulated.
Towards the goal of creating such neuronal networks we have applied microfabricated elastomeric membranes, surface modification and our unique laser cell patterning system to create defined neuronal circuits with single-cell precision …

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The Effects Of Academic And Social Integration On Two-Year College Students' Persistence In Developmental Courses, Mark Kevin Taylor Aug 2009

The Effects Of Academic And Social Integration On Two-Year College Students' Persistence In Developmental Courses, Mark Kevin Taylor

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The purpose of the study was to investigate the effects of academic integration and social integration on the persistence of students enrolled in developmental courses at a two-year community college. First, the study covered an examination of the levels of academic integration and social integration of students participating in developmental studies. Second, the study included an examination of the relationships between academic integration and persistence, and social integration and persistence. The first research question explored the levels of academic integration of students enrolled in developmental courses at a two-year college. The second research question explored the levels of social integration …

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Teacher-Student Interactions And Domain-Specific Motivation: The Relationship Between Students' Perceptions Of Teacher Interpersonal Behavior And Motivation In Middle School Science, Julie Brockman Smart Aug 2009

Teacher-Student Interactions And Domain-Specific Motivation: The Relationship Between Students' Perceptions Of Teacher Interpersonal Behavior And Motivation In Middle School Science, Julie Brockman Smart

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This study examined interactions between middle school science students' perceptions of teacher-student interactions and their motivation for learning science. Specifically, in order to better understand factors affecting middle school students' motivation for science, this study investigated the interactions between middle school students' perceptions of teacher interpersonal behavior in their science classroom and their efficacy, task value, mastery orientations, and goal orientation for learning science. This mixed methods study followed a sequential explanatory model (Cresswell & Plano-Clark, 2007). Quantitative and qualitative data were collected in two phases, with quantitative data in the first phase informing the selection of participants for the …

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Lyapunov-Based Coordinated Control Of An Underactuated Unmanned Aerial Vehicle And Robot Manipulator, Dongbin Lee Aug 2009

Lyapunov-Based Coordinated Control Of An Underactuated Unmanned Aerial Vehicle And Robot Manipulator, Dongbin Lee

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This Ph.D. dissertation describes nonlinear tracking control results for a quadrotor helicopter unmanned aerial vehicle (UAV) towards the ultimate goal of controlling a combined UAV plus robot manipulator system (UAVRM). The quadrotor UAV is a helicopter that has four independent rotors that provide vertical lift: these four independent forces are managed in order to directly provide lift, pitch, roll, and yaw of the vehicle. Horizontal translations result from pitch and roll actions, the system is underactuated in the sense that there are only four control inputs to move the six degree-of-freedom aircraft. There are exising dynamic models of the quadrotor …

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Factoring Polynomials And Groebner Bases, Genhua (Yinhua) Guan Aug 2009

Factoring Polynomials And Groebner Bases, Genhua (Yinhua) Guan

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Factoring polynomials is a central problem in computational algebra and number theory and is a basic routine in most
computer algebra systems (e.g. Maple, Mathematica, Magma, etc). It has been extensively studied
in the last few decades by many mathematicians and computer scientists. The main approaches include Berlekamp's method
(1967) based on the kernel of Frobenius map, Niederreiter's method (1993) via an ordinary differential equation,
Zassenhaus's modular approach (1969), Lenstra, Lenstra and Lovasz's lattice reduction (1982), and Gao's method via a partial differential equation (2003). These methods and their recent improvements due to van Hoeij (2002) and
Lecerf et al …

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Understanding The Antioxidant Mechanism Of Inorganic Selenium, Oxo- Sulfur, And Polyphenol Compounds, And The Biological Implications Of Functionalized Nanoparticles, Ria Ramoutar Aug 2009

Understanding The Antioxidant Mechanism Of Inorganic Selenium, Oxo- Sulfur, And Polyphenol Compounds, And The Biological Implications Of Functionalized Nanoparticles, Ria Ramoutar

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Inorganic selenium, oxo-sulfur, and polyphenol compounds are found in foods and dietary supplements, and are recognized for their nutritional benefits and their potential to treat or prevent diseases caused by oxidative stress. In our experiments to determine the effects of inorganic selenium compounds on iron-mediated DNA damage, Na2SeO33 and SeO2 exhibit antioxidant and pro-oxidant activities depending on concentrations of both the compound and hydrogen peroxide. Additional experiments demonstrate that iron coordination is a novel mechanism responsible for the observed activities. In similar experiments, oxo-sulfur compounds prevent Cu+/ H2O2-mediated DNA damage significantly …

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