The efficient separation of hydrogen from methane and light hydrocarbons for clean energy applications remains a technical challenge in membrane science. To address this issue, we prepared a graphene-wrapped MFI (G-MFI) molecular-sieving membrane for the ultrafast separation of hydrogen from methane at a permeability reaching 5.8 × 10 barrers at a single gas selectivity of 245 and a mixed gas selectivity of 50.
View Article and Find Full Text PDFIn this work, a hollow LiNiCoMnO (H-NCM) nanosphere cathode with excellent electrochemical performance is developed for lithium-ion batteries. Preparation of the H-NCM nanospheres involves the sacrificial template method, in which carbon nanospheres work as the template and polyvinylpyrrolidone works as an additive. Structural and morphological analyses show that the as-prepared H-NCM nanospheres are highly uniform with diameters of approximately 50 nm and wall thicknesses of 10 nm.
View Article and Find Full Text PDFWe 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.
View Article and Find Full Text PDFMesoporous anatase TiO2/carbon composite nanospheres (designated as meso-ATCCNs) were successfully synthesized via a facile soft-templated self-assembly followed by thermal treatment. Structural and morphological analyses reveal that the as-synthesized meso-ATCCNs are composed of primary TiO2 nanoparticles (∼5 nm), combined with in situ deposited carbon either on the surface or between the primary TiO2 nanoparticles. When cycled in an extended voltage window from 0.
View Article and Find Full Text PDFPolybrominated 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.
View Article and Find Full Text PDFWater Sci Technol
February 2011
This study evaluates the ability of Beijerinckia indica (B. indica) as a biomaterial for aerobic biofilm barriers. B.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFEnviron Sci Technol
February 2009
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.
View Article and Find Full Text PDFWe 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.
View Article and Find Full Text PDFSpecific 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.
View Article and Find Full Text PDFThe receptor for advanced glycation end products (RAGE) may promote diabetic vascular and renal disease through the activation of intracellular signaling pathways that promote oxidative stress. Oxidative stress is a mediator of hyperglycemia-induced cell injury and a unifying theme for all mechanisms of diabetic complications, but there are few studies on the expression and potential contribution of RAGE in diabetic neuropathy. The current study demonstrates that dorsal root ganglia neurons express functional RAGE and respond to the RAGE ligand S100 with similar downstream signaling, oxidative stress, and cellular injury as other diabetic complication-prone tissues.
View Article and Find Full Text PDFJ Environ Sci Health A Tox Hazard Subst Environ Eng
October 2006
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.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
December 2004
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.
View Article and Find Full Text PDFHere 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.
View Article and Find Full Text PDFCross-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.
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