A controlled greenhouse experiment was conducted to study the fraction, uptake and fixation of phosphorus (P) and potassium (K) in three soils with contrasting characteristics. The experiment was carried out in two phases, viz., sorghum-Sudangrass depletion and test crop experiment with maize with three levels of fertility status (depleted, original and fertilized with 40 mg kg-1 P and K) and t...

A model predicting the structure of repulsive, spherically symmetric, monodisperse particles confined between two walls is presented. When plate separations are small, only one layer of particles can be confined; however, when the plate separation is increased, multiple layers will eventually form. We study the buckling transition of a single flat layer as the double layer state develops. Exper...

CH3NH3PbI3 capped PbS colloidal quantum dots have been successfully fabricated by solid-state ligand exchange from oleate and oleylamine capped PbS. The optimal solar cells made by layer-by-layer solution deposition give a high power conversion efficiency of 4.25% with an impressive short-circuit photocurrent density of 24.83 mA cm-2.

High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nano...

We study the analogy between buckled colloidal monolayers and the triangular-lattice Ising antiferromagnet. We calculate free-volume-induced Ising interactions, show how lattice deformations favor zigzag stripes that partially remove the Ising model ground-state degeneracy, and identify the martensitic mechanism prohibiting perfect stripes. Slowly inflating the spheres yields jamming as well as...

Quantitative analytical applications of surface-enhanced Raman spectrometry (SERS) on colloidal substrates are hindered by the experimental difficulties in measuring intensities with precision comparable to that of state-of-theart spectrochemical techniques. Several factors, both adsorbateand substrate-dependent, contribute to the poor reproducibility of SERS. Since the observed enhancement fac...

We have developed structure/toxicity relationships for amorphous silica nanoparticles (NPs) synthesized through low-temperature colloidal (e.g., Stöber silica) or high-temperature pyrolysis (e.g., fumed silica) routes. Through combined spectroscopic and physical analyses, we have determined the state of aggregation, hydroxyl concentration, relative proportion of strained and unstrained siloxane...

Dissolved and colloidal concentrations of Al, Fe, Mn, Cu, Zn, Cd, and Pb were determined in the Mullica River, New Jersey, and its tributaries on nine occasions between August 1994 and September 1995. Cross-flow filtration (CFF) at a nominal 10 kDa cutoff was used to separate total dissolved (,0.45 mm) riverine metals into colloidal and truly dissolved fractions. Reproducibility tests on full p...

We examine the photophysics of a colloidal suspension of C(60) particles in a micellar solution of Triton X-100 and water, prepared via a new synthesis which allows high-concentration suspensions. The particle sizes are characterized by transmission electron microscopy and dynamic light scattering and found to be somewhat polydisperse in the range of 10-100 nm. The suspension is characterized o...

A method to prepare monodisperse and simultaneously NMR-visible and fluorescent colloidal particles is described, and a systematic approach to obtain spectrally resolved diffusion coefficient for every component in a monodisperse colloidal suspension is presented. We also prepared bidisperse colloidal suspensions, where each colloid component has a distinct NMR spectral signature, and obtained ...