31,100 research outputs found
Charge Transfer-oxy Radical Mechanism for Anti-cancer Agents
The proposal is advanced that anti-cancer drugs generally function by charge transfer resulting in formation of toxic oxy radicals which destroy the neoplasm. Electrochemical studies were performed with some of the main types of agents: iminium ions (adenine iminium from alkylating species, iminium metabolite of 6-mercaptopurine, nitidine, other polynuclear iminiums) and metal complexes (Pt(II)diaquodiammine-guanosine, copper salicylaldoximes). Reduction potentials ranged from -0.4 to -1.2 V. Literature data for quinones are presented and radiation is discussed. Based on the theoretical framework, a rationale is offered for the carcinogen-anti-cancer paradox and the role of antioxidants
Designing HMO, an Integrated Hardware Microcode Optimizer
This Paper Discusses an Algorithm for Optimizing the Density and Parallelism of Micro coded Routines in Micro programmable Machines. Besides the Algorithm itself, the Algorithm\u27s Uses, Design Integration Problems, Architectural Requirements, and Adaptability to Conventional Machine Characteristics Are Also Discussed and Analyzed. Even Though the Paper Proposes a Hardware Implementation of the Algorithm, the Algorithm is Viewed as an Integral Part of the Entire Microcode Generation and Usage Process, from Initial High-Level Input into a Software Microcode Compiler Down to Machine-Level Execution of the Resultant Microcode on the Host Machine. It is Believed that, by Removing Much of the Traditionally Time-Consuming and Machine-Dependent Microcode Optimization from the Software Portion of This Process, the Algorithm Can Improve the overall Process
Modeling Concrete Masonry Walls Subjected To Explosive Loads
Concrete masonry unit walls subjected to blast pressure were analyzed with the finite element method, with the goal of developing a computationally-efficient and accurate model. Wall behavior can be grouped into three modes of failure, which correspond to three ranges of blast pressures. Computational results were compared to high-speed video images and debris velocities obtained from experimental data. A parametric analysis was conducted to determine the sensitivity of computed results to critical modeling values. It was found that the model has the ability to replicate experimental results with good agreement. However, it was also found that, without knowledge of actual material properties of the specific wall to be modeled, computational results are not reliable predictors of wall behavior
Gluons, quarks, and the transition from nonperturbative to perturbative QCD
Lattice-based investigations of two fundamental QCD quantities are described,
namely the gluon and quark propagators in Landau gauge. We have studied the
Landau gauge gluon propagator using a variety of lattices with spacings from a
= 0.17 to 0.41 fm. We demonstrate that it is possible to obtain scaling
behavior over a very wide range of momenta and lattice spacings and to explore
the infinite volume and continuum limits. These results confirm that the Landau
gauge gluon propagator is infrared finite. We study the Landau gauge quark
propagator in quenched QCD using two forms of the O(a)-improved propagator and
we find good agreement between these. The extracted value of the infrared quark
mass in the chiral limit is found to be 300 +/- 30 MeV. We conclude that the
momentum regime where the transition from nonperturbative to perturbative QCD
occurs is Q^2 approx 4GeV^2.Comment: 8 pages, 6 figures, 1 table. Talk presented by AGW at the Workshop on
Lepton Scattering, Hadrons and QCD, March 26-April 5, 2001, CSSM, Adelaide,
Australia. To appear in the proceeding
There\u27s a Pattern Here: The Case to Integrate Environmental Security into Homeland Security Strategy
The time is long overdue to acknowledge that global climate and resource stresses, encompassed by the concept of environmental security (ES), are an increasingly important part of homeland security (HS) study and practice, by even the most restricted definitions of HS. Environmental security issues will affect global economic and political stability, US national interests, and the risk of war and terrorism. Just as homeland security encompasses many complex issues and interconnected subfields, environmental security (ES) is interdisciplinary by nature. In essence, ES is an emergent discipline borrowing from a combination of environmental studies â which decades ago integrated environmental science with public policy â and the broader observations of how environmental change, extreme weather events and resource scarcity issues impact domestic and international security. In a two-part argument, we first observe the growing environmental and resource-related security threats at every level of analysis, from global to individual levels as consequences of warming-induced climate alterations. Next, given the significant impacts on local, regional, and international geopolitical stability, we discuss why environmental security threats must be incorporated into both homeland and national security strategic planning. Developing a theory of environmental security seems central to a more complete understanding of homeland security and a more modern concept of national security
Control and modelling of capillary flow of epoxy resin in aligned carbon nanotube forests
This paper examines the mechanism of infiltration by capillary flow of epoxy resin into vertically-aligned carbon nanotube forests. The resin viscosity during curing was characterized by rheometry. Carbon nanotube forests were brought into contact with resin at a range of times during curing, therefore at a range of viscosities. The penetration of the resin into the forests was measured using electron microscopy, X-ray micro-computed tomography and energy-dispersive X-ray spectroscopy, the latter relying on a chromium-complex dye additive which acts as a marker for the presence of resin. Experimental results were compared to a simulation based on the Implicit LucasâWashburn equation for capillary flow. It was found that prior to the resin gel point, the resin penetrates through the full height of the forest. Close to the gel point, the flow into the forest ceases, leaving unwetted regions of nanotubes. Understanding the relationship between resin flow in nanotube structures and the resin viscosity and curing has important application in the fabrication of nanocomposite materials. This âpartial wettingâ effect is a key requirement for a previously proposed method for the fabrication of carbon nanotube composites by additive manufacture (AM) which would provide strong interlayer reinforcement combined with the versatility of AM.Airbus Corp. Ltd. (Airbus Group)University of Exete
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Solvent and ligand substitution effects on electrocatalytic reduction of CO2 with [Mo(CO)4(x,xĘš-dimethyl-2,2â˛-bipyridine)] (x = 4-6) enhanced at a gold cathodic surface
A series of molybdenum tetracarbonyl complexes with dimethylâsubstituted 2,2â˛âbipyridine (dmbipy) ligands were investigated by cyclic voltammetry (CV) combined with infraâred spectroelectrochemistry (IRâSEC) in tetrahydrofuran (THF) and Nâmethylâ2âpyrrolidone (NMP) to explore their potential in a reduced state to trigger electrocatalytic CO2 reduction to CO. Addressed is their ability to take advantage of a lowâenergy, COâdissociation twoâelectron ECE pathway available only at an Au cathode. A comparison is made with the reference complex bearing unsubstituted 2,2Ęšâbipyridine (bipy). The methyl substitution in the 6,6Ęšâpositions has a large positive impact on the catalytic efficiency. This behaviour is ascribed to the advantageous positioning of the steric bulk of the methyl groups, which further facilitates CO dissociation from the 1eâ reduced parent radical anion. In the contrary, the substitution in the 4,4â˛âpositions appears to have a negative impact on the catalytic performance, exerting a strong stabilizing effect on the Ďâaccepting CO ligands and, in THF, preventing exploitation of the lowâenergy dissociative pathway
The Effect of Personal Factors on Consumer Purchase Decision (Case Study: Everbest Shoes)
Accesories, and so on. Manado city also experiences the fashion trends. Branded product such as Everbest already known to the Manado public.The objectives of this research are to know the personal factors influencing the purchasing decision of Everbest Shoes product in Manado and identify factors that have dominant effects on personal factors influencing purchase decision of Everbest Shoes in Manado. To achieve these objectives, the personal factors are analyzed with the multiple linear regression method. After an examination of 100 respondents, the result of this research shows that Personal Factors which are Age & Life-cycle Stage, Occupation and Economic Condition, Lifestyle, and Personality have significant effect on consumer purchase decision of Everbest Shoes in Manado.This research indicates that the personal factors influence the purchase decision of Everbest Shoes in Manado. Therefore, Everbest should be considering a strategy to maintain the company\u27s performance
Fabrication of Three Dimensional Layered Vertically Aligned Carbon Nanotube Structures and their Potential Applications
This paper proposes a new technique for fabrication of vertically aligned carbon nanotube (VACNT) structures, controlled in shape, height and functionality, through continuous successive growth of VACNT layers by chemical vapour deposition (CVD) combined with patterning strategies. This was achieved by vacuum deposition of additional catalyst material onto the original VACNT âforestâ layer. A second forest layer is then observed to grow underneath the first by CVD. It is proposed that the new catalyst material diffuses through the porous nanotube forest to coat the growth substrate underneath. The enhanced height, coating, and vertical alignment of the nanotube forests were verified by electron microscope observation. By repeating this process, aligned nanotube bi-layers and tri-layers were grown, producing a âstackâ of nanotube layers. By using a âshadow maskâ patterning technique to screen areas of the original forest from catalyst deposition, the growth can be confined to specific areas of the substrate. Potentially, these multilayer nanotube structures would have diverse applications as long composite reinforcements, pân junctions for electronic devices, or to allow the production of near net shape complex multilayer nanotube structures
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