Conventional confidence intervals reflect uncertainty due to random error but omit uncertainty due to biases, such as confounding, selection bias, and measurement error. Such uncertainty can be quantified, especially if the investigator has some idea of the amount of such bias. A traditional sensitivity analysis produces one or more point estimates for the exposure effect hypothetically adjuste...

We present a strategy to increase the sensitivity of resonators to the presence of specific molecules in the gas phase, measured by the change in resonant frequency as the partial pressure of the molecule changes. We used quartz crystals as the resonators and coated them with three different thin films (<1 microm thick) of porous silica: silica xerogel, silica templated by an ordered hexagonal ...

In the past, helical shapes in nature have inspired inventions such as the water screw for agriculture, the retaining screw for wine presses, and architectural designs for spiral staircases. Similarly, these days helix-shaped DNA, proteins and carbon nanotubes evoke great interest in biotechnology and nanotechnology. Also biomimetic synthesis of helical morphologies of calcium carbonate, barium...

The alignment of mesochannels in a mesoporous silica film on a freshly cleaved mica surface, prepared by an evaporation-induced self-assembly process, is unexpectedly found to be unidirectional with the narrowest directional distribution.

We present the synthesis of monodisperse cone-shaped silica colloids and their fluorescent labeling. Rod-like silica colloids prepared by ammonia-catalyzed hydrolysis and condensation of tetraethyl orthosilicate in water droplets containing polyvinylpyrrolidone cross-linked by citrate ions in pentanol were found to transform into cone-shaped particles upon mild etching by NaOH in water. The dia...

Dissolved silica species are naturally occurring, ubiquitous groundwater constituents with corrosion-inhibiting properties. Their influence on the performance and longevity of iron-based permeable reactive barriers for treatment of organohalides was investigated through long-term column studies using Connelly iron as the reactive medium. Addition of dissolved silica (0.5 mM) to the column feed ...

For the first time, a non-destructive technique for spatially resolving the location and relative concentration of rare-earth dopants in an optical fiber is demonstrated. This novel technique is based on computerized tomographic detection of spontaneous emission and achieves micron-scale spatial resolution with the aid of oil-immersion imaging. In addition to elucidating interactions between th...

A simple preparation process of alkylamide phase for reversed-phase HPLC (RP-HPLC) is described. The process includes aminopropyltrimethoxysilane firstly reacted with octanoyl chloride, then the intermediate was coupled onto porous silica. The resultant bonded silica has a reproducible ligand surface concentration and homogenous bonded ligand distribution on the porous silica. Characterization ...

This article describes the preparation of pyrene confined mesostructured silica nanoparticles for the trace detection of trinitrotoluene (TNT) in the aqueous phase. Pyrene confined mesostructured silica nanoparticles were prepared using a facile one-pot method where pyrene molecules were first encapsulated in the hydrophobic parts of cetyltrimethylammonium micelles and then silica polymerized a...

We present a successive microfluidic approach to create and characterize hierarchical catalyst structures consisting of metal-decorated nanoparticles that are assembled into porous microparticles ("supraball" catalysts). First, using a silicon microreactor, platinum nanoparticles with a very narrow size distribution are grown and immobilized uniformly onto iron oxide/silica core-shell nanospher...