Wong group – abstracts 2007 gas kansas city


Indocyanine green (ICG) is a photosensitive reagent with clinically relevant diagnostic and therapeutic applications. Recently, ICG has been investigated for its utility as an exogenous chromophore during laser-induced heating. However, ICGapos;s effectiveness remains hindered by its molecular instability, rapid circulation kinetics, and nonspecific

systemic distribution. To overcome these limitations, we have encapsulated ICG within dextran-coated mesocapsules (MCs). Our objective in this study was to explore the ability of MCs to induce thermal damage in response to laser irradiation. To simulate tumorous tissue targeted with MCs, cylindrical phantoms p gasol were prepared consisting of gelatin, intralipid emulsion, and

various concentrations of MCs. The phantoms were embedded within fresh chicken breast tissue representing surrounding normal tissue. The tissue models were irradiated at = 808 nm for 10 min at constant power (P = 4.2 W). Five hypodermic thermocouples were used to record the temperature at various depths below the tissue surface and transverse distances from the laser

beam central axis during irradiation. Temperature profiles were processed to remove the baseline temperature and influence of light absorption by the thermocouple and subsequently used to calculate a damage index based on the Arrhenius damage integral. Tissue models containing MCs experienced a maximum temperature change of 18.5 °C. Damage index calculations showed that

the heat generation from MCs at these gas dryer vs electric dryer safety parameters is sufficient to induce thermal damage, while no damage was predicted in the absence of MCs. ICG maintains its heat-generating capabilities in response to NIR laser irradiation when encapsulated within MCs. Such encapsulation provides a potentially useful methodology for laser-induced therapeutic strategies.

We report a systematic study of improved wetting behavior for thin polymer films containing nanoparticles, as a function of nanoparticle size and concentration, the energy of the substrate and the dielectric properties of the nanoparticles. An enthalpy matched system consisting of polystyrene nanoparticles in linear polystyrene is used to show that nanoparticles are uniformly distributed in the film after spin coating and drying. However,

on annealing the film above its bulk glass transition temperature these nanoparticles segregate strongly to the solid substrate. We find that for a wide range of film thicknesses and nanoparticle sizes, a substrate coverage of nanoparticles of approximately a monolayer is required for dewetting inhibition. Cadmium selenide quantum dots also inhibit dewetting of polystyrene thin films, again when a monolayer is present. Moreover, TEM microscopy images indicate

that CdSe quantum dots segregate primarily to the air interface. Theoretical interpretation of these phenomena suggests that gain of linear chain configurational entropy promotes segregation of nanoparticles to the solid substrate, as occurs for polystyrene z gas el salvador empleos nanoparticles; however, for CdSe nanoparticles this is offset by surface energy or enthalpic terms which promote segregation of the nanoparticles to the air interface.

Carbon-supported Au particles with mean sizes ranging from 5 to 42 nm and unsupported Au powder were evaluated as catalysts in the aqueous-phase oxidation of CO and glycerol. For the aqueous-phase oxidation of CO at pH 14 and 300 K, the turnover frequency (TOF) for the 5-nm Au particles was 5 s -1, whereas the TOF for large supported Au (42 nm) and bulk Au were only 0.5 and m gasbuddy 0.4 s -1, respectively. The observed rate of

peroxide formation during CO oxidation also was much higher on the small Au particles. Oxidation of glycerol in the aqueous phase at 333 K and elevated pH over the same catalysts revealed a similar influence of particle size, with the 5-nm Au particles giving a TOF of 17 s -1 at pH 13.8 and the larger particles and bulk Au nearly an order of magnitude less active. However, large Au particles (20 nm) were more selective to glyceric

In this work we investigated the synthesis of composite organic and inorganic membranes for proton conduction. Particles derived from metal alkoxides gas in oil pressure washer (M(OR)n) sol-gel processes (Ti, Zr, W with phosphoric acid) were embedded in polymeric matrices of poly-vinyl alcohol, (3-glycidoxypropyl)-trimethoxysilane and ethylene glycol. The structure of

the composite membranes was complex as several IR peaks were convoluted, indicating the assignment of several functional groups. However, the peaks assigned to OH groups reduced in intensity in the composite membranes, indicating that cross-linking of hydroxyl groups in the organic and inorganic phases of the membrane may have occurred. The particles allowed

for re-arrangement of the polymer matrix, as crystallinity was reduced compared to a polymer blank membrane. The composite membrane process resulted in homogeneous dispersion of nanoparticles into the polymer film. Proton conduction of the inorganic phase was mainly dominated by titania. Binary mixtures of titania phosphate (sample name TiP) resulted in proton

conduction of 7.15 × 10?2 S.cm?1, one order of magnitude higher than zirconia phosphate (ZrP). The addition of Zr and W to TiP forming ternary or quaternary phases also led to lower proton conduction as compared to TiP. Similar trends were also observed for the composite membranes, though the TiP composite membrane proton conduction reduced after several hours

We show it is possible to assemble nanoparticle?polymer layers in a controllable manner dictated by the difference in nano-object morphology and dielectric properties. A thin (10?100 nm) layer of the two components is spin coated onto a solid substrate and the system thermally aged to activate a cross-linking process between polymer molecules. The nanoparticles

segregate to the solid substrate prior to complete cross-linking if entropic forces are dominant or to the air interface if dielectric (surface energy) forces are properly tuned. Subsequent layers are then spin coated onto the layer below, and the process is repeated to create electricity production in china layered structures with nanometer accuracy useful for tandem solar cells, sensors, optical coatings, etc.