87 research outputs found
Modules-at-infinity for quantum vertex algebras
This is a sequel to \cite{li-qva1} and \cite{li-qva2} in a series to study
vertex algebra-like structures arising from various algebras such as quantum
affine algebras and Yangians. In this paper, we study two versions of the
double Yangian , denoted by and
with a nonzero complex number. For each nonzero
complex number , we construct a quantum vertex algebra and prove
that every -module is naturally a -module. We also show
that -modules are what we call
-modules-at-infinity. To achieve this goal, we study what we call
-local subsets and quasi-local subsets of \Hom (W,W((x^{-1}))) for any
vector space , and we prove that any -local subset generates a (weak)
quantum vertex algebra and that any quasi-local subset generates a vertex
algebra with as a (left) quasi module-at-infinity. Using this result we
associate the Lie algebra of pseudo-differential operators on the circle with
vertex algebras in terms of quasi modules-at-infinity.Comment: Latex, 48 page
Hollow mesoporous silica nanoparticles for intracellular delivery of fluorescent dye
In this study, hollow mesoporous silica nanoparticles (HMSNs) were synthesized using the sol-gel/emulsion approach and its potential application in drug delivery was assessed. The HMSNs were characterized, by transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), nitrogen adsorption/desorption and Brunauer-Emmett-Teller (BET), to have a mesoporous layer on its surface, with an average pore diameter of about 2 nm and a surface area of 880 m2/g. Fluorescein isothiocyanate (FITC) loaded into these HMSNs was used as a model platform to assess its efficacy as a drug delivery tool. Its release kinetic study revealed a sequential release of FITC from the HMSNs for over a period of one week when soaked in inorganic solution, while a burst release kinetic of the dye was observed just within a few hours of soaking in organic solution. These FITC-loaded HMSNs was also found capable to be internalized by live human cervical cancer cells (HeLa), wherein it was quickly released into the cytoplasm within a short period of time after intracellular uptake. We envision that these HMSNs, with large pores and high efficacy to adsorb chemicals such as the fluorescent dye FITC, could serve as a delivery vehicle for controlled release of chemicals administered into live cells, opening potential to a diverse range of applications including drug storage and release as well as metabolic manipulation of cells
Entropy analysis on convective film flow of power-law fluid with nanoparticles along an inclined plate
Entropy generation in a two-dimensional steady laminar thin film convection flow of a non-Newtonian nanofluid (Ostwald-de-Waele-type power-law fluid with embedded nanoparticles) along an inclined plate is examined theoretically. A revised Buongiorno model is adopted for nanoscale effects, which includes the effects of the Brownian motion and thermophoresis. The nanofluid particle fraction on the boundary is passively rather than actively controlled. A convective boundary condition is employed. The local nonsimilarity method is used to solve the dimensionless nonlinear system of governing equations. Validation with earlier published results is included. A decrease in entropy generation is induced due to fluid friction associated with an increasing value of the rheological power-law index. The Brownian motion of nanoparticles enhances thermal convection via the enhanced transport of heat in microconvection surrounding individual nanoparticles. A higher convective parameter implies more intense convective heating of the plate, which increases the temperature gradient. An increase in the thermophoresis parameter decreases the nanoparticle volume fraction near the wall and increases it further from the wall. Entropy generation is also reduced with enhancement of the thermophoresis effect throughout the boundary layer
Stability of nanofluids in quiescent and shear flow fields
An experimental study was conducted to investigate the structural stability of ethylene glycol-based titanium dioxide nanoparticle suspensions (nanofluids) prepared by two-step method. The effects of particle concentration, fluid temperature, shear rate and shear duration were examined. Particle size and thermal conductivity measurements in quiescent state indicated the existence of aggregates and that they were stable in temperatures up to 60°C. Shear stability tests suggested that the structure of nanoparticle aggregates was stable in a shear interval of 500-3000 s-1 measured over a temperature range of 20-60°C. These findings show directions to resolve controversies surrounding the underlying mechanisms of thermal conduction and convective heat transfer of nanofluids
Native and nonnative audio-visual perception of English fricatives in quiet and café-noise backgrounds
This study examines audio-visual perception of second-language (L2) speech, with the goal of investigating the extent to which the auditory and visual input modalities are integrated in processing unfamiliar L2 speech. Native (Canadian English) and nonnative (Mandarin) perceivers responses were collected for a set of fricative-initial syllables presented with a quiet and a cafe-noise background, and presented in four ways: congruent audio-visual (AVc), incongruent audio-visual (AVi), audio-only (A) and visual-only (V). Results show that for both native groups, performance was better in the AVc condition than A or V condition; and better in quiet than in cafe-noise background. A comparison of the native and nonnative performance revealed that Mandarin participants showed (1) poorer identification of the L2 interdental fricatives, (2) a greater degree of reliance on visual information, even when auditory information was available, and (3) a higher percentage of McGurk responses with the incongruent AV speech. These findings indicate that although normatives were able to use visual information, they failed to adopt the visual cues that are linguistically characteristic of the L2 sounds, suggesting a language-specific AV processing pattern. However, similarities between the two native groups are also indicative of possible perceptual universals involved. Together they point to an integrated network in speech pr
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