Predicting the Breakthrough Performance of "Gating" Adsorbents Using Osmotic Framework-Adsorbed Solution Theory.

We present an experimental and theoretical study of the breakthrough performance of the flexible metal-organic framework Cu(bpy)(BF) (bpy = 4,4'-bipyridine), termed ELM-11. Pure CO, He, CH, and N gases, as well as binary gas mixtures of those species, were used to perform breakthrough experiments on ELM-11. ELM-11 exhibits a stepped breakthrough curve for CO not seen in rigid adsorbents.

A dynamic multimedia environmental and bioaccumulation model for brominated flame retardants in Lake Huron and Lake Erie, USA.

Polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) may pose a worldwide pollution problem because of their persistence, long-range transport capability, and predisposition to bioaccumulate. The ubiquitous presence of PBBs and PBDEs has heightened interest in determination of their fate. We report results for a fugacity-based dynamic environmental and bioaccumulation model of the fate of hexabromobiphenyl (hexaBB) discharged into the Saginaw Bay region of Lake Huron, USA.

Ability of Beijerinckia indica to degrade phenanthrene and reduce hydraulic conductivity.

This study evaluates the ability of Beijerinckia indica (B. indica) as a biomaterial for aerobic biofilm barriers. B.

Density functional theory studies on the relative reactivity of chloroethenes on zerovalent iron.

The gas-phase dissociation of perchloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cis-DCE) on zerovalent iron Fe(110) was investigated using periodic density functional theory (DFT) with the generalized gradient approximation (GGA) and climbing image nudged elastic band method (CI-NEB). Activation energies and dechlorination rate constants for reductive beta-elimination of the chloroethene compounds were calculated using an Arrhenius equation with theoretically calculated vibrational frequencies for the compounds. Activation energies were found to decrease as the chlorination number increases.

Density functional theory studies of chloroethene adsorption on zerovalent iron.

Adsorption of perchloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cis-DCE) on zerovalent iron is investigated using density functional theory (DFT) to evaluate hypotheses concerning the relative reactivity of these compounds on zerovalent iron. Four different chloroethene adsorption modes on the Fe(110) surface were studied using periodic DFT and the generalized gradient approximation (GGA). Of the adsorption sites examined, the atop site, where the chloroethene C==C bond straddles a surface iron atom, was the most energetically favorable site for the adsorption of all three chloroethenes.

Mobile trap algorithm for zinc detection using protein sensors.

We present a mobile trap algorithm to sense zinc ions using protein-based sensors such as carbonic anhydrase (CA). Zinc is an essential biometal required for mammalian cellular functions although its intracellular concentration is reported to be very low. Protein-based sensors like CA molecules are employed to sense rare species like zinc ions.

Assessment of sperm chemokinesis with exposure to jelly coats of sea urchin eggs and resact: a microfluidic experiment and numerical study.

Specific peptides contained within the extracellular layer, or jelly coat, of a sea urchin egg have been hypothesized to play an important role in fertilization, though separate accounting of the effects of chemoattraction, chemokinesis, sperm agglomeration and the other possible roles of the jelly coat have not been reported. In the present study, we used a microfluidic device that allowed determination of the differences in the diffusion coefficients of sperm of the purple sea urchin Arbacia punctulata subjected to two chemoattractants, namely the jelly coat and resact. Our objectives were twofold: (1) to experimentally determine and compare the diffusion coefficients of Arbacia punctulata spermatozoa in seawater, jelly coat solution and resact solution; and (2) to determine the effect of sea urchin sperm diffusion coefficient and egg size on the sperm-egg collision frequency using stochastic simulations.

Denitrification and chemotaxis of Pseudomonas stutzeri KC in porous media.

Chemotaxis is an important mechanism by which microorganisms are dispersed in porous media. A vigorous chemotactic response to concentration gradients formed by microbial consumption of chemoattractants can accelerate transport of bacteria to highly contaminated regions of soils and sediments, enhancing the efficiency of in situ bioremediation operations. Although chemotaxis plays a key role in establishment of biodegradation zones in the subsurface, the effects of physical heterogeneity on bacterial motility are poorly understood.

Connectivity, clusters, and transport: use of percolation concepts and atomistic simulation to track intracellular ion migration.

The cytoskeleton is an intracellular highway system, teaming with signalling ions that zip from site to site along filaments. These tiny particles alternately embrace and slip free of protein receptors with wide-ranging affinities, as they propagate in a blur of motion along cytoskeletal corridors at transport rates far exceeding ordinary diffusive motion. Recent experimental breakthroughs have enabled optical tracking of these single ion-binding events in the physiological and diseased states.

In situ imaging of mitochondrial outer-membrane pores using atomic force microscopy.

Here we describe a technique for imaging of the outer contours of the mitochondrial membrane using atomic force microscopy, subsequent to or during a toxic or metabolic challenge. Pore formation in both glucose-challenged and 1,3-dinitrobenzene (DNB)-challenged mitochondria was observed using this technique. Our approach enables quantification of individual mitochondrial membrane pore formations.

Configurational bias Monte Carlo simulation of phase segregation in block copolymer networks.

Cross-linked block copolymers are used as adhesives in fiber-reinforced composite material manufactures for automotive applications. Good adhesion between the polymer matrix and fibers in the interphase region is required for the structural integrity of these materials. Experimental evidence indicates that superior adhesion is obtained when phase segregation occurs between the two matrix phase block copolymers.