Dean flow-coupled inertial focusing in curved channels

Passive particle focusing based on inertial microfluidics was recently introduced as a high-throughput alternative to active focusing methods that require an external force field to manipulate particles. In inertial microfluidics, dominant inertial forces cause particles to move across streamlines and occupy equilibrium positions along the faces of walls in flows through straight micro channels. In this study, we systematically analyzed the addition of secondary Dean forces by introducing curvature and show how randomly distributed particles entering a simple u-shaped curved channel are focused to a fixed lateral position exiting the curvature. We found the lateral particle focusing position to be fixed and largely independent of radius of curvature and whether particles entering the curvature are pre-focused (at equilibrium) or randomly distributed. Unlike focusing in straight channels, where focusing typically is limited to channel cross-sections in the range of particle size to create single focusing point, we report here particle focusing in a large cross-section area (channel aspect ratio 1: 10). Furthermore, we describe a simple u-shaped curved channel, with single inlet and four outlets, for filtration applications. We demonstrate continuous focusing and filtration of 10 mu m particles (with > 90% filtration efficiency) from a suspension mixture at throughputs several orders of magnitude higher than flow through straight channels (volume flow rate of 4.25ml/min). Finally, as an example of high throughput cell processing application, white blood cells were continuously processed with a filtration efficiency of 78% with maintained high viability. We expect the study will aid in the fundamental understanding of flow through curved channels and open the door for the development of a whole set of bio-analytical applications

trans-Dioxo-bis(dimethylglyoximato)ruthenium(VII) perchlorate: an active oxidation catalyst for the electrochemical epoxidation of olefins

High-valent metal-oxo complexes of the composition [Ru<SUP>VI</SUP>(H-dmg)<SUB>2−</SUB> (H<SUB>2</SUB>O)(H)]<SUP>2+</SUP> [Ru<SUP>VII</SUP>(H<SUB>2</SUB>-dmg)<SUB>2</SUB>(OH)(O)<SUP>4+</SUP> where dmg = dimethylglyoximato are formed in situ by the electrochemical oxidation of [Ru<SUP>III</SUP>(H-dmg)<SUB>2−</SUB> (C1O<SUB>4</SUB>)<SUB>2</SUB>]<SUP>−</SUP> in the pH range 1-2 and [Ru<SUP>VI</SUP>(H-dmg)<SUB>2</SUB>(H<SUB>2</SUB>O)(O)]<SUP>2+</SUP> and [Ru<SUP>VII</SUP>-(H-dmg)<SUB>2</SUB>(O)<SUB>2</SUB>]<SUP>+</SUP> in the pH range 2-3.5. These intermediates act as catalysts in the electrocatalytic epoxidation of cyclohexene and cyclooctene to the corresponding epoxides

A TUNABLE DECELLULARIZED LIVER-BASED HYBRID BIOINK

Decellularized extracellular matrix is a tissue-specific biomaterial that recapitulates the complexity of the inherent tissue environment to elicit cellular response. Here, a multi-material decellularized liver (dLM)-based bioink with gelatin is developed and polyethylene glycol crosslinking is used to enhance the viscoelasticity of the dLM. We evaluated the necessity of a post-printing secondary cross-linker mushroom tyrosinase to improve robustness and long term stability. We further demonstrate it's biocompatibility using liver specific gene analysis of HepG2 cells. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved

Mononuclear bis(dimethylglyoximato)ruthenium(III) complexes with different appended axial groups: highly efficient catalysts for water oxidation

Mononuclear ruthenium(III) complexes [Ru(H-dmg)<SUB>2</SUB>XY]<SUP>n</SUP> (n=−1, when X=Y=Cl<SUP>−</SUP> or ClO<SUB>4</SUB><SUP>−</SUP>n=0 when X=Cl<SUP>−</SUP> and Y = imidazole or 2-methylimidazole) were used as catalysts in water oxidation to molecular oxygen by electrolytic and chemical methods. The evolved oxygen in both methods was measured at atmospheric pressure (30°C) using a specially-designed gas volumetric apparatus. The maximum turnover number of the above complexes (mol O<SUB>2</SUB> evolved per mole complex per hour) are reported

Structure of catechol 1,2-dioxygenase from Pseudomonas arvilla.

International audienceCatechol 1,2-dioxygenase was first studied by Hayaishi and colleagues in 1950. In 1967, catechol 1,2-dioxygenase from Pseudomonas arvilla C-1 (PaCTD) was chosen as a model system for the catecholic intradiol dioxygenases due to its activity, stability and expression level. Here we report the 2.65 A structure of the betabeta isozyme of PaCTD. The structure supports the hypothesis first made by Vetting and Ohlendorf [The 1.8A crystal structure of catechol 1,2-dioxygenase reveals a novel hydrophobic helical zipper as a subunit linker, Struct. Fold. Des. 8 (2000) 429-440.] that the catechol 1,2-dioxygenases are lipid binding proteins. The 5 amino-terminal helices involved in dimerization and forming the lipid binding site are shown to be plastic in their positions and orientations. The sequence differences between the alpha and beta polypeptides are located at the part of the monomers distant from dimerization surface and thus permit the formation of the 3 isozymes (alphaalpha, alphabeta, and betabeta) of PaCTD. The reported inactivation by sulfhydryl-modifying reagents is explained by the structure. The 10-residue Helix F (residues 203-212) is proposed to be central in communicating between the lipid binding site and the active site

Synthesis and characterization of some ruthenium(V) oxo complexes of the Schiff base, bis(salicylaldehyde)-o-phenylenediamine, with appended Cl<SUP>&#8722;</SUP>, imidazole and 2-methylimidazole: the first examples of stable oxo complexes via direct oxygenation

Oxygenation of ruthenium(III) Schiff base complexes of the composition K[RuIII(Saloph)Cl2] and [RuIII(Saloph)XCl] (Saloph=bis(salicylaldehyde)-o- phenylenediamine; X=imidazole (Im), 2-methylimidazole (2-MeIm)) with molecular oxygen gives the oxo derivatives of the composition, [RuV(Saloph)X- (O)]+ (X=Cl, Im or 2-MeIm). The oxo complexes were also synthesized by the reaction of [RuIII- (Saloph)XCl] with PhIO or H2O2. The complexes thus obtained were characterized by analytical data, molar conductance, magnetic susceptibility, spectroscopic and electrochemical methods. Kinetics of the oxygenation reaction have also been investigated