Sensitive detection of estrogenic mycotoxin zearalenone by open sandwich immunoassay.

Zearalenone (ZEA) is an estrogenic mycotoxin produced by Fusarium sp., and its production on corn and small grains during storage has been of considerable concern. For sensitive ZEA detection, we applied an open sandwich (OS) immunoassay that can noncompetitively detect monovalent antigens utilizing an antigen-induced enhancement of the V(H)/V(L) interaction. We cloned the V(H) and V(L) cDNAs of anti-ZEA mAb to a split-Fv phagemid pKST2, and firstly both V(H) and V(L) fragments were displayed on M13 phage p9 and p7, respectively, using an amber suppressor, TG-1, as a host. The split-Fv phage showed specific binding to immobilized ZEA, which was well inhibited by free ZEA. Then, the V(H)/V(L) interaction and its antigen-dependency were analyzed using a non-suppressor HB2151 as a host to produce V(H)-displaying phage and his/myc-tagged soluble V(L) in the culture supernatant. By capturing V(L) with an anti-myc or -his antibody and probing bound V(H)-phage, ZEA was successfully detected with a superior detection limit as well as a wider working range than those of a competitive assay. Also, essentially the same results were reproduced with purified V(H)-alkaline phosphatase and MBP-V(L) fusion proteins.     

Preliminary study of two immiscible liquid layers subjected to a horizontal temperature gradient

Marangoni convection, driven by interfacial instability due to a surface tension gradient, presents a significant problem in the crystal growth process. To achieve better materials processing, it is necessary to suppress and control this convection, especially in crystal growth using Liquid Encapsulated Czochralski techniques in which the melt is encapsulated in an immiscible medium. Marangoni convection can occur at the liquid-liquid interface and at the gas-liquid free surface. Buoyancy driven convection can also affect and complicate the flow. The present report studied Marangoni convection in a two-liquid layer system in an open and enclosed cavity. Flow in the cavity was subjected to a horizontal temperature gradient. Interactive flow near the liquid-liquid interface was measured by the Particle Image Velocimetry (PIV) technique. The measured flow field is in good agreement with numerical predictions.     

Bowl-shaped Cu(I) metallamacrocyclic ethylene and carbonyl adducts as structural analogues of organic calixarenes

Three novel Cu(I) metallacalixarenes with C(2)H(4) and CO legs, in which an anion is accommodated in the inside cavity, were self-assembled by anion templation and have been structurally characterized.     

Photochromism of novel metal coordination polymers with 1,2-Bis(2'-methyl-5'-(carboxylic acid)-3'-thienyl)perfluorocyclopentene in the crystalline phase

Three new metal complexes with 1,2-bis(2'-methyl-5'-(carboxylic acid)-3'-thienyl)perfluorocyclopentene (BM-5-CATP) were synthesized and characterized by X-ray diffraction analysis. BM-5-CATP serves as a bis-monodentate ligand that bridges metal centers to generate three 1D polymers. The two thienyl rings in the three complexes adopt antiparallel fashions, and the distances of 3.39, 3.53, and 3.57 A between the two reactive carbons are short enough to allow photocyclizations to occur in the crystalline phase. [Co(BM-5-CATP)(py)2(MeOH)2] (1) displayed effective photoisomerization in the crystalline phase. Interestingly, solvated 1 underwent a solid-state conversion upon heating to generate, through the release of the coordinated MeOH and rearrangement of the coordination geometry, the desolvated form (1a), while maintaining reversible photochromism. The removal of the solvent led to obvious changes in physical properties such as color and magnetic properties. The ESR spectra of 1 and 1a changed reversibly upon photoexcitation, indicating changes in coordination geometry accompanied by photoreaction. The magnetic susceptibilities of 1 and 1a showed no obvious changes, suggesting that the cobalt-cobalt interaction through the long bridging BM-5-CATP is less effective. Both [Cu(BM-5-CATP)(py)3](EtOH)(py)1.8 (2) and [Zn(BM-5-CATP)(phen)(H2O)] (3) exhibited reversible photoreactions in the crystalline phase. However, 3 did not show remarkable spectral changes because of steric hindrance from the coordinated bulky phenanthroline and the intramolecular H bonds.     

CALET Observations during the First 5 Years on the ISS

Physics of Atomic Nuclei - The CALorimetric Electron Telescope CALET is collecting science data on the International Space Station since October 2015 with excellent and continuous performance....     

High pressure functionalization of diaza-crown ether and thioether

Abstract

Functionalized diaza-18-crown ethers and thioethers were prepared by high pressure S_NAr reactions (0.8 GPa, 100°C) of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane and the related thio analogue with heteroaromatic halides.     

Pd-catalyzed copolymerization of methyl acrylate with carbon monoxide: structures, properties and mechanistic aspects toward ligand design

Full details are provided for the alternating copolymerization of acrylic esters with carbon monoxide (CO) catalyzed by palladium species bearing a phosphine-sulfonate bidentate ligand. The copolymer of methyl acrylate (MA) and CO had complete regioregularity with stereocenters that slowly epimerize in the presence of methanol. In the presence of ethylene, terpolymers of MA/ethylene/CO were also prepared. The glass transition temperatures of the co- and terpolymers were higher than that of the ethylene/CO copolymer. Both experimental and theoretical investigations were performed to clarify the superior nature of the palladium phosphine-sulfonate system compared to an unsuccessful conventional palladium diphosphine system: (i) The reversible insertion of CO was directly observed with the isolated alkylpalladium complexes, [{o-((o-MeOC(6)H(4))(2)P)C(6)H(4)SO(3)}PdCH(CO(2)Me)CH(2)COMe], whereas it was not observed with the corresponding complex bearing 1,2-bis(diphenylphosphino)ethane (DPPE). (ii) The transition state of the subsequent MA insertion, the rate-determining step of the catalytic cycle, was lower in energy in the phosphine-sulfonate system than in the DPPE system. This stabilization could be attributed to the less hindered sulfonate moiety as well as the stronger back-donation from palladium to the electron-deficient olefin, which is located trans to the sulfonate.     

Coordination-insertion copolymerization of allyl monomers with ethylene

Coordination-insertion copolymerization of allyl monomers with ethylene was developed by using a palladium/phosphine-sulfonate catalyst. A variety of allyl monomers, including allyl acetate, allyl alcohol, protected allylamines, and allyl halides, were copolymerized with ethylene to form highly linear copolymers that possess in-chain -CH(2)CH(CH(2)FG)- units.     

Domain population in SrTiO3 below the cubic-to-tetragonal phase transition

High-angle double-crystal X-ray diffractometry (HADOX) has been applied to measure the intensity around three reciprocal lattice points: 400, 040 and 004 of SrTiO₃. Each point splits into two in the tetragonal phase according to the appearance of three kinds of domains; the temperature dependence of the intensity of component peaks at these points was measured under identical conditions. The results show that the domain population varies with temperature in a range of about 20 K below the transition. It is found, however, that the total intensities of 400 and 004 of the tetragonal phase are constant; this is observed by summing up the relevant intensity at the three reciprocal lattice points.