Fate and cotransport of Pb(II) and Cd(II) heavy ions with bentonite colloidal flow in saturated porous media: The role of filter cake, counter ions, colloid concentration, and fluid velocity.

This study examines the transport and retention of colloidal particles and heavy ions in porous sand, focusing on the environmental risks associated with waste from oil and gas drilling. Experimental and numerical models assess the influence of flow rate, external filter cake layer, and ionic strength on bentonite clay particles and heavy ions, such as cadmium (Cd) and lead (Pb), in near-wellbore (high-flux) and far-field (low-flux) scenarios. Colloidal filtration theory and the one-dimensional convection-dispersion equation with two-site kinetic model for attachment and detachment were utilized to calibrate and predict the transport of colloidal suspension in porous media.

Hydrotalcite stability during long-term exposure to natural environmental conditions.

Hydrotalcite-like compounds are a group of layered double hydroxides widely studied as sorbents to remove organic and inorganic contaminants under laboratory conditions. This study is a proof-of-concept of the long-term fate of hydrotalcite compounds under natural environmental conditions, to bridge the gap between laboratory studies and their field application as sorbents. Hydrotalcite (HT) with intercalated carbonate species (HT-CO) and dodecyl sulphate (HT-DS) were synthesised and placed in two groundwater monitoring wells in Denmark, one contaminated with chlorinated hydrocarbons and another with uncontaminated groundwater.

Chloroform compatible, thiol-ene based replica molded micro chemical devices as an alternative to glass microfluidic chips.

Polymeric microfluidic chips offer a number of benefits compared to their glass equivalents, including lower material costs and ease and flexibility of fabrication. However, the main drawback of polymeric materials is often their limited resistance to (organic) solvents. Previously, thiol-ene materials were shown to be more solvent resistant than most other commonly used polymers; however, they still fall short in "harsh" chemical environments, such as when chlorinated solvents are present.

Soluble and immobilized graphene oxide activates complement system differently dependent on surface oxidation state.

Graphene oxide (GO) is believed to become applicable in biomedical products and medicine, thereby necessitating appropriate safety evaluation dependent on their applications and the route of administration. We have examined the effect of GO form (in solution versus immobilized) and oxidation state on two related elements of innate immunity: the complement system and interleukin-6 (IL-6) release in human blood. In solution, there was a decrease in GO-mediated complement activation with decreasing surface oxygen content (and altered oxygen functionality), whereas with immobilized GO complement response were reversed and increased with decreasing oxygen content.

Click Chemistry Mediated Functionalization of Vertical Nanowires for Biological Applications.

Semiconductor nanowires (NWs) are gaining significant importance in various biological applications, such as biosensing and drug delivery. Efficient and controlled immobilization of biomolecules on the NW surface is crucial for many of these applications. Here, we present for the first time the use of the Cu(I) -catalyzed alkyne-azide cycloaddition and its strain-promoted variant for the covalent functionalization of vertical NWs with peptides and proteins.

Grafted biomembranes containing membrane proteins--the case of the leucine transporter.

Here, we bind the sodium dependent amino acid transporter on nitrilotriacetic acid/polyethylene glycol functionalized gold sensors in detergents and perform a detergent-lipid exchange with phosphatidylcholine. We characterize the LeuT structure in the adsorbed film by magnetic contrast neutron reflection using the predicted model from molecular dynamic simulations.

Covalent and stable CuAAC modification of silicon surfaces for control of cell adhesion.

Stable primary functionalization of metal surfaces plays a significant role in reliable secondary attachment of complex functional molecules used for the interfacing of metal objects and nanomaterials with biological systems. In principle, this can be achieved through chemical reactions either in the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging.

Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface.

The discovery of two-dimensional electron gases (2DEGs) in SrTiO3-based heterostructures provides new opportunities for nanoelectronics. Herein, we create a new type of oxide 2DEG by the epitaxial-strain-induced polarization at an otherwise nonpolar perovskite-type interface of CaZrO3/SrTiO3. Remarkably, this heterointerface is atomically sharp and exhibits a high electron mobility exceeding 60,000 cm(2) V(-1) s(-1) at low temperatures.

Ultrathin reduced graphene oxide films as transparent top-contacts for light switchable solid-state molecular junctions.

A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case.

A new class of extended tetrathiafulvalene cruciform molecules for molecular electronics with dithiafulvene-4,5-dithiolate anchoring groups.

Cruciform motifs with two orthogonally oriented π-extended tetrathiafulvalenes and with differently protected thiolate end-groups are synthesized by stepwise coupling reactions. The molecules are subjected to single-molecule conductivity studies in a break-junction and to conducting probe atomic force microscopy studies in a self-assembled monolayer on gold.

Online shear viscosity measurement of starchy melts enriched in wheat bran.

Unlabelled: Addition of wheat bran to flours modifies their expansion properties after cooking extrusion. This can be attributed to changes in the melt shear viscosity at the die. The effect of wheat bran concentration added to achieve 2 levels of dietary fibers of 12.

Solution-processed ultrathin chemically derived graphene films as soft top contacts for solid-state molecular electronic junctions.

A novel method using solution-processed ultrathin chemically derived graphene films as soft top contacts for the non-destructive fabrication of molecular junctions is demonstrated. We believe this protocol will greatly enrich the solid-state test beds for molecular electronics due to its low-cost, easy-processing and flexible nature.

Molecular junctions based on SAMs of cruciform oligo(phenylene ethynylene)s.

Cruciform oligo(phenylene ethynylene)s (OPEs) with an extended tetrathiafulvalene (TTF) donor moiety (OPE5-TTF and OPE3-TTF) and their simple analogues (OPE5-S and OPE3) without conjugated substituents were used to form high-quality self-assembled monolayers (SAMs) on ultraflat gold substrates. Molecular junctions based on these SAMs were investigated using conducting-probe atomic force microscopy (CP-AFM). The TTF substituent changes the molecular orbital energy levels and decreases the HOMO-LUMO energy gap, resulting in a 9-fold increase in conductance for both TTF cruciform OPEs compared to the unsubstituted analogues.

Reversible electron-transfer reactions within a nanoscale metal oxide cage mediated by metallic substrates.

Transition metal oxides exhibit a rich collection of electronic properties and have many practical applications in areas such as catalysis and ultra-high-density magnetic data storage. Therefore the development of switchable molecular transition metal oxides has potential for the engineering of single-molecule devices and nanoscale electronics. At present, the electronic properties of transition metal oxides can only be tailored through the irreversible introduction of dopant ions, modifying the electronic structure by either injecting electrons or core holes.

Supramolecular assembly facilitating adsorbate-induced chiral electronic states in a metal surface.

Through the application of optically active second-harmonic generation measurements (OA-SHG) we have demonstrated that the adsorption of amino acids cysteine (HSCH(2)CHNH(2)COOH) and penicillamine (HSC(CH3)(2)CHNH(2)COOH) from solution can induce chiral electronic states in an initially achiral polycrystalline Au film. The chiral induction is strongly dependent upon the pH of the deposition solution; adsorption of penicillamine and cysteine under acidic conditions (pH = 3) induces the same level of optical activity, whereas at pH = 11, the optical activity induced by cysteine is reduced by ca. 50% and penicillamine does not induce optical activity at all.