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2012

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Articles 331 - 344 of 344

Full-Text Articles in Physical Sciences and Mathematics

C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman Dec 2011

C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman

Kevin D. Ausman

Stable aqueous fullerene colloidal suspensions (nC60) are demonstrated to rely on the [6,6]-closed epoxide derivative of the fullerene (C60O) for stability. This derivative is present, though often unrecognized, in small quantities in nearly all C60 starting materials due to a reaction with air. The low-yield formation of nC60 from organic solvent solutions results from a preferential partitioning and thus enrichment of C60O in the colloidal particles. This partitioning is significantly retarded in the nC60 synthesis method that does not involve organic solvent solutions: long-term stirring in water. Instead, this method relies on trace levels of ozone in the ambient atmosphere …


Pmma-Libob Gel Electrolyte For Application In Lithium Ion Batteries, Siti Rohana Majid, Kufian M. Z., Aziz M. F., Shukur M. F., Rahim A. S., Ariffin N. E., Shuhaimi N. E. A., Yahya R., Arof A. K. Dec 2011

Pmma-Libob Gel Electrolyte For Application In Lithium Ion Batteries, Siti Rohana Majid, Kufian M. Z., Aziz M. F., Shukur M. F., Rahim A. S., Ariffin N. E., Shuhaimi N. E. A., Yahya R., Arof A. K.

Siti Rohana Majid

Different amounts of lithium bis(oxalato) borate (LiBOB) have been added into a mixture of equal weights of ethylene carbonate (EC) and propylene carbonate (PC). The variation of molar conductivity of the LiBOB based liquid electrolyte with square root of salt concentration obeys the weak electrolyte theory. The 0.6 M LiBOB in EC/PC liquid electrolyte with highest room temperature conductivity of 4.8 mS cm(-1) was chosen for further work. 10 to 50 wt.% PMMA was added to this composition and heated between 343 and 353 K for 20 min to obtain the gel polymer electrolytes (GPEs). Due to its dry state …


A Comparative Analysis Of Decision Trees Vis-À-Vis Other Computational Data Mining Techniques In Automotive Insurance Fraud Detection, Adrian Gepp, Kuldeep Kumar, J Holton Wilson, Sukanto Bhattacharya Dec 2011

A Comparative Analysis Of Decision Trees Vis-À-Vis Other Computational Data Mining Techniques In Automotive Insurance Fraud Detection, Adrian Gepp, Kuldeep Kumar, J Holton Wilson, Sukanto Bhattacharya

Adrian Gepp

No abstract provided.


Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor Dec 2011

Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor

Nima Rahbar

Atomistic simulations are performed to investigate the nano-scale interfacial fracture toughness between graphene and epoxy. Nano-mechanical properties of graphene and epoxy are initially studied using molecular dynamics simulations. A novel method is suggested to accurately model the behavior of the graphen/epoxy interface during the curing process of the epoxy as a function of temperature. The computed interfacial fracture energy is computed at about 0.203 J/m2, which is in good agreement with available experimental data. It is also shown that the adhesion between cured epoxy and graphene layer increases the pre-existing waviness of the 2-dimensional graphene sheet in a 3-dimensional space. …


Toward Unification Of Exact And Heuristic Optimization Methods, John Hooker Dec 2011

Toward Unification Of Exact And Heuristic Optimization Methods, John Hooker

John Hooker

No abstract provided.


Induced Subgraphs Of Johnson Graphs, Ramin Naimi, Jeffrey Shaw Dec 2011

Induced Subgraphs Of Johnson Graphs, Ramin Naimi, Jeffrey Shaw

Ramin Naimi

The Johnson graph J(n,N) is defined as the graph whose vertices are the n-subsets of the set {1,2,...,N}, where two vertices are adjacent if they share exactly n - 1 elements. Unlike Johnson graphs, induced subgraphs of Johnson graphs (JIS for short) do not seem to have been studied before. We give some necessary conditions and some sufficient conditions for a graph to be JIS, including: in a JIS graph, any two maximal cliques share at most two vertices; all trees, cycles, and complete graphs are JIS; disjoint unions and Cartesian products of JIS graphs are JIS; every JIS graph …


Graphene Oxide And Its Electrochemical Performance, Siti Rohana Majid, Ban F. Y., Huang N. M., Lim H. N. Dec 2011

Graphene Oxide And Its Electrochemical Performance, Siti Rohana Majid, Ban F. Y., Huang N. M., Lim H. N.

Siti Rohana Majid

In this study, graphene oxide (GO) was synthesized from graphite flakes using simplified Hummer's method. Field Emission Scanning Electron Microscopy (FESEM) image showed that the GO nanosheets had an average area 7000 mu m(2) with lateral dimension of up to 150 mu m. The X-Ray Diffraction (XRD) pattern revealed a (002) diffraction peak, signifying the successful synthesis of GO. GO solution was cast on an aluminum (Al) foil placed in a petri dish and left to dry to form an electrode made up of GO film on the Al foil (GO-Al). It was found that GO-Al exhibited equivalent series resistance …


A Significant Component Of Ageing (Dna Damage) Is Reflected In Fading Breeding Colors: An Experimental Test Using Innate Antioxidant Mimetics In Painted Dragon Lizards, Mats Olsson, Michael Tobler, Mo Healey, Cecile Perrin, Mark Wilson Dec 2011

A Significant Component Of Ageing (Dna Damage) Is Reflected In Fading Breeding Colors: An Experimental Test Using Innate Antioxidant Mimetics In Painted Dragon Lizards, Mats Olsson, Michael Tobler, Mo Healey, Cecile Perrin, Mark Wilson

Mark R Wilson

A decade ahead of their time, von Schantz et al. united sexual selection and free radical biology by identifying causal links between deep-rooted physiological processes that dictate resistance to toxic waste from oxidative metabolism (reactive oxygen species, ROS), and phenotypic traits, such as ornaments.Ten years later, these ideas have still only been tested with indirect estimates of free radical levels (oxidative stress) subsequent to the action of innate and dietary antioxidants. Here, we measure net superoxide (a selection pressure for antioxidant production) and experimentally manipulate superoxide antioxidation using a synthetic mimetic of superoxide dismutase (SOD), Eukarion 134 (EUK). We then …


Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman Dec 2011

Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman

Mark R Wilson

The aberrant aggregation of the amyloid-β peptide into β-sheet rich, fibrillar structures proceeds via a heterogeneous ensemble of oligomeric intermediates that have been associated with neurotoxicity in Alzheimer’s disease (AD). Of particular interest in this context are the mechanisms by which molecular chaperones, part of the primary biological defenses against protein misfolding, influence Aβ aggregation. We have used single-molecule fluorescence techniques to compare the interactions between distinct aggregation states (monomers, oligomers, and amyloid fibrils) of the AD-associated amyloid-β(1–40) peptide, and two molecular chaperones, both of which are upregulated in the brains of patients with AD and have been found colocalized …


Investigating Cognitive Task Difficulties And Expert Skills In E-Learning Storyboards Using A Cognitive Task Analysis Technique, Siti Salwah Salim Dec 2011

Investigating Cognitive Task Difficulties And Expert Skills In E-Learning Storyboards Using A Cognitive Task Analysis Technique, Siti Salwah Salim

Siti Salwah Salim Prof. Dr.

E-learning storyboards have been a useful approach in distance learning development to support interaction between instructional designers and subject-matter experts. Current works show that researchers are focusing on different approaches for use in storyboards, and there is less emphasis on the effect of design and process difficulties faced by instructional designers and subject-matter experts. This study explores problem aspects of the cognitive task and the skills required of subject-matter experts by applying a cognitive task analysis approach from the expert point of view. The result shows that subject-matter experts face difficulties in making decisions on three elements during e-learning course …


Photometry Of 17 Jovian Trojan Asteroids, Linda French, Robert Stephens, Daniel Coley, Ralph Megna Dec 2011

Photometry Of 17 Jovian Trojan Asteroids, Linda French, Robert Stephens, Daniel Coley, Ralph Megna

Linda French

Lightcurves for 17 Jupiter Trojan asteroids were obtained from Cerro Tololo Interamerican Observatory, Lowell Observatory, and GMARS Observatory from 2010 August to 2012 March.


Environmentally Friendly Organic Synthesis Using Bismuth(Iii) Compounds, Ram Mohan, Scott Krabbe Dec 2011

Environmentally Friendly Organic Synthesis Using Bismuth(Iii) Compounds, Ram Mohan, Scott Krabbe

Ram S. Mohan

Abstract With increasing environmental concerns, the need for environmentally friendly organic synthesis has gained increased importance. In this regard, bismuth (III) compounds are especially attractive as “green” reagents and catalysts for organic synthesis. Bismuth(III) compounds are remarkably nontoxic, relatively air and moisture stable, and easy to handle. The contributions from our laboratory in the last 5 years in the field of applications of bismuth(III) compounds as catalysts are presented.


Structuring Persistent Chat Conversations: Experimental Results Of The Chatsistance Tool, Siti Salwah Salim Dec 2011

Structuring Persistent Chat Conversations: Experimental Results Of The Chatsistance Tool, Siti Salwah Salim

Siti Salwah Salim Prof. Dr.

Abstract This research targets persistency by introducing new features in ‘Chatsistance’, a persistent chat tool that employs speech act theory and an explicit referencing technique to structure the chat log, and by providing further options for retrieving information. Earlier theory is related to the linguistics and characteristics of user statements. The later technique shows the relation of artefacts in an interconnected context named ‘explicit referencing’. Although speech actswere previously used in the field of chat, it is the first time that this theory has been used for the purpose of enhancing persistency combined with an explicit referencing technique,which together provide …


Net Superoxide Levels: Steeper Increase With Activity In Cooler Female And Hotter Male Lizards, Cissy Ballen, Mo Healey, Mark Wilson, Michael Tobler, Erik Wapstra, Mats Olsson Dec 2011

Net Superoxide Levels: Steeper Increase With Activity In Cooler Female And Hotter Male Lizards, Cissy Ballen, Mo Healey, Mark Wilson, Michael Tobler, Erik Wapstra, Mats Olsson

Mark R Wilson

"Ectotherms increase their body temperature in response to ambient heat, thereby elevating their metabolic rate. An often inferred consequence of this is an overall upregulation of gene expression and energetic expenditure, and a concomitant increased production of reactive oxygen species (e. g. superoxide) and, perhaps, a shortened lifespan. However, recent work shows that this may be a superficial interpretation. For example, sometimes a reduced temperature may in fact trigger up-regulation of gene expression. We studied temperature and associated activity effects in male and female Australian painted dragon lizards (Ctenophorus pictus) by allowing the lizards to bask for 4 h versus …