We have successfully reached the world record 32.35 T direct-current magnetic field by using a homemade all-superconducting magnet. The magnet has consisted of a 15 T low temperature superconductor outsert coil and two high temperature superconductor no-insulation (NI) insert coils using a conductor tape coated of REBCO (REBa 2 Cu 3 O x , where RE=Y, Gd). This result proves the feasibility of reaching a strong magnetic field up to 32 T by using the NI process as well as the superconductor magnet with insulation. This magnet is one of the essential parts of the 'Synergetic Extreme Condition User Facility' project, which provides expertize, instrumentation, and infrastructure for investigating matter science under extreme physical conditions. We thought that such a strong superconductor magnet would bring the possibility to explore more mystery in physics, medicine, pharmacy, etc.
Soil microbial activity played a key role in the bioefficacy persistence of neonicotinoid insecticides and therefore significantly affected their technical profile after soil application.
Microorganisms that bring about the aerobic transformation of imidacloprid (IMI) were isolated and screened, and the microbial regio- and stereoselective hydroxylation of IMI was studied. Some bacteria and fungi transformed IMI to 5-hydroxyl IMI. Bacterium Stenotrophomonas maltophilia CGMCC 1.1788 resting cells transformed IMI into R-5-hydroxyl IMI at the highest conversion rate. The enzyme catalyzed the stereoselective hydroxylation at position C12 of IMI in the imidazolidine ring. Under acidic conditions, 5-hydroxyl IMI was converted into olefin IMI in high molar conversion yield. The olefin IMI exhibited about 19 and 2.2 times more insecticidal efficacy than IMI against horsebean aphid imago and nymph, respectively, and about 1.4 times more active than IMI against brown planthopper imago. The transformation rate of IMI by resting cells of S. maltophilia CGMCC 1.1788 was promoted significantly by some carbohydrates and organic acids. The reaction medium with 5% sucrose resulted in 8.3 times greater biotransformation yield as compared with that without sucrose.
Neonicotinoid insecticide pollution in soil and water poses serious environmental risks. Microbial biodegradation is an important neonicotinoid insecticide degradation pathway in the environment. In this study, 70.0% of the acetamiprid in a 200 mg/L solution was degraded by actinomycetes Streptomyces canus CGMCC 13662 (isolated from soil) in 48 h, and the acetamiprid degradation half-life was 27.7 h. Acetamiprid was degraded to IM-1-2 ((E)-1-(1-(((6chloropyridin-3-yl)methyl)(methyl) amino)ethylidene)urea) through hydrolysis of the cyanoimine moiety. Gene cloning and overexpression indicated that a novel nitrile hydratase with three unusual subunits (AnhD, AnhE, and AnhA) without accessory protein mediated IM-1-2 formation. The purified nitrile hydratase responsible for degrading acetamiprid had a K m of 5.85 mmol/L and a V max of 15.99 U/mg. A homology model suggested that AnhD-Glu56 and AnhE-His21 play important roles in the catalytic efficiency of the nitrile hydratase. S. canus CGMCC 13662 could be used to remediate environments contaminated with acetamiprid.
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