Classification of turbulence modification by dispersed spheres using a novel dimensionless number

A novel dimensionless parameter, the particle moment number Pa, was derived using dimensional analysis of the particle-laden Navier-Stokes equations, in order to understand the underlying physics of turbulence modification by particles. A set of 80 previous experimental measurements where the turbulent kinetic energy was modified by particles was examined, and all results could clearly be divided into three groups in Re-Pa mappings. The turbulence attenuation region was observed between the augmentation regions with two critical particle momentum numbers.     

Polynomial Time Samplable Distributions

This paper studies the complexity of the polynomial-time samplable (P-samplable) distributions, which can be approximated within an exponentially small factor by sampling algorithms in time polynomial in the length of their outputs. The paper shows that common assumptions in complexity theory yield the separation of polynomial-time samplable distributions from the polynomial-time computable distributions with respect to polynomial domination, average-polynomial domination, polynomial equivalence, and average-polynomial equivalence.     

Subunit analyses of a novel thermostable glucose dehydrogenase showing different temperature properties according to its quaternary structure

We previously reported a novel glucose dehydrogenase (GDH) showing two peaks in the optimum temperature for the reaction at around 45°C and at around 75°C. Each peak derived from hetero-oligomeric enzyme, constructed from two distinct peptides with an α-subunit (MWs 67,000) and β-subunit (MWs 43,000), and a single peptide enzyme containing an α-subunit alone. The function of the two subunits in the thermostable co-factor binding GDH was investigated. The results of spectroscopic analyses indicated that the α-subunit contained an unknown co-factor showing specific fluorescence spectra like pyrroloquinoline quinone (PQQ), and the β-subunit was cytochrome c. Moreover, the results of a urea denaturation and reconstitution experiment suggested that the dissociation of the hetero-oligomeric complex to a single peptide was reversible. The kinetic parameter analyses for glucose and the electron mediator also suggested that the β-subunit was responsible for electron transfer from the catalytic center of the α-subunit to the electron mediator.     

Preparation of Metal Oxide Nanotubes Using Gelators as Structure-Directing Agents

Summary: Cationic gelators, capable of gelling alcohols, were developed as structure-directing agents for preparing metal oxides. The sol-gel polymerization of metal alkoxides using the gelators as templates afforded metal oxide nanotubes. The unique structure of metal oxides was created by transferring the shape of fibrous aggregates of gelator. The electrostatic interaction between cationic gelator and anionic metal oxide precursor plays an important role for acting as templates.     

1,2,3-Tri(9-anthryl)benzene: Photophysical Properties and Solid-State Intermolecular Interactions of Radially Arranged,Congested Aromatic π-Planes**

We report the Negishi coupling based synthesis of 1,2,3-tri(9-anthryl)benzene derivatives containing three radially arranged anthracenes in a π-cluster. In the crystalline state of the unsubstituted derivative, intermolecular π–π and CH–π interactions between the anthracene units drive the formation of the two-dimensional packing structure. Owing to though-space π-conjugation between anthracene units, the substances have unique electronic properties. The excited-state dynamic behavior occurring between the three anthracene moieties, such as exciton localization/delocalization, was elucidated by means of transient absorption measurements and quantum chemical calculations. Interestingly, even though the three anthracenes are closely oriented with approximately 3.0 Å between their C-9 positions, exciton localization on two anthracene units is energetically favorable because of the flexible nature of the radially arranged aromatic rings.     

Exploiting a C–N Bond Forming Cytochrome P450 Monooxygenase for C–S Bond Formation

C–S bond formation reactions are widely distributed in the biosynthesis of biologically active molecules, and thus have received much attention over the past decades. Herein, we report intramolecular C–S bond formation by a P450 monooxygenase, TleB, which normally catalyzes a C−N bond formation in teleocidin biosynthesis. Based on the proposed reaction mechanism of TleB, a thiol-substituted substrate analogue was synthesized and tested in the enzyme reaction, which afforded the unprecedented sulfur-containing thio-indolactam V, in addition to an unusual indole-fused 6/5/8-tricyclic product whose structure was determined by the crystalline sponge method. Interestingly, conformational analysis revealed that the SOFA conformation is stable in thio-indolactam V, in sharp contrast to the major TWIST form in indolactam V, resulting in differences in their biological activities.     

Comparison of two preparation methods of supported Li?Ni catalyst on alumina for selective oxidation of methane

Lithium-added nickel catalysts on alumina were prepared for CO₂ reforming of methane by two methods, precipitation and impregnation. Performances of the catalysts were investigated by TG, CO-adsorption and SEM analysis. The catalyst with ratio of Li/Ni=1.0 prepared by precipitation method has high nickel dispersion, catalytic activity and stability for CO₂ reforming of methane.     

Multiresidue analytical method for the determination of antimicrobials, preservatives, benzotriazole UV stabilizers, flame retardants and plasticizers in fish using ultra high performance liquid chromatography coupled with tandem mass spectrometry

A multiresidue analytical method for the determination of emerging pollutants belonging to personal care products (PCPs) (antimicrobials, preservatives), benzotriazole UV stabilizers (BUVSs) and organophosphorus compounds (OPCs) in fish has been developed using high speed solvent extraction (HSSE) followed by silica gel clean up and ultra fast liquid chromatography coupled with tandem mass spectrometry (UFLC–MS/MS) analysis. Developed extraction and clean up method yielded good recovery (>70%) for all the four groups of emerging pollutants, i.e. antimicrobials (78.5–85.6%), preservatives (85.0–89.4%), BUVSs (70.9–112%) and OPCs (81.6–114%; except for TEP – 68.9% and TPeP – 58.1%) with RSDs ranging from 0.7 to 15.4%. Intra- and inter-day repeatabilities were less than 19.8% and 19.0%, respectively at three spiked levels. The concentrations were given in lipid weight (lw) basis, and the method detection limits were achieved in the lowest range of 0.001–0.006 ng g⁻¹ for two antimicrobials, 0.001–0.015 ng g⁻¹ for four preservatives, 0.0002–0.009 ng g⁻¹ for eight BUVSs and 0.001–0.014 ng g⁻¹ for nine OPCs. Finally, the method was successfully validated as a simple and fast extraction method for the determination of 23 compounds belonging to PCPs, BUVSs and OPCs and applied to the analysis of three species of fish from Manila Bay, the Philippines. Concentrations ranged from 27 to 278 ng g⁻¹ for antimicrobials, 6.61 to 1580 ng g⁻¹ for paraben preservatives, −1 for BUVSs and ND (not detected) to 266 ng g⁻¹ for OPCs suggesting the ubiquitous contamination by these emerging pollutants in Manila Bay. This is the first method developed for the determination of triclocarban, four paraben preservatives and four BUVSs, in fish.