Macrofluidic coaxial flow platforms to produce tunable magnetite nanoparticles : a study of the effect of reaction conditions and biomineralisation protein Mms6

Magnetite nanoparticles’ applicability is growing extensively. However, simple, environmentally-friendly, tunable synthesis of monodispersed iron-oxide nanoparticles is challenging. Continuous flow microfluidic synthesis is promising; however, the microscale results in small yields and clogging. Here we present two simple macrofluidics devices (cast and machined) for precision magnetite nanoparticle synthesis utilizing formation at the interface by diffusion between two laminar flows, removing aforementioned issues. Ferric to total iron was varied between 0.2 (20:80 Fe3+:Fe2+) and 0.7 (70:30 Fe3+:Fe2+). X-ray diffraction shows magnetite in fractions from 0.2–0.6, with iron-oxide impurities in 0.7, 0.2 and 0.3 samples and magnetic susceptibility increases with increasing ferric content to 0.6, in agreement with each other and batch synthesis. Remarkably, size is tuned (between 20.5 nm to 6.5 nm) simply by increasing ferric ions ratio. Previous research shows biomineralisation protein Mms6 directs magnetite synthesis and controls size, but until now has not been attempted in flow. Here we report Mms6 increases magnetism, but no difference in particle size is seen, showing flow reduced the influence of Mms6. The study demonstrates a versatile yet simple platform for the synthesis of a vast range of tunable nanoparticles and ideal to study reaction intermediates and additive effects throughout synthesis

Insights into the interaction of iodide and iodine with Cu(II)-loaded bispicolylamine chelating resin and applications for nuclear waste treatment

Radioiodine is a challenging contaminant to remove from aqueous wastestreams, resulting from spent nuclear fuel reprocessing. To create a selective, economical adsorbent, a Cu-loaded bispicolylamine chelating resin was produced, from commercially available reagents and its performance for removal of aqueous iodide and iodine was assessed. The resin possessed a large equilibrium uptake capacity of 305 ± 14 mg.g−1 iodide and 2940 ± 180 mg.g−1 total iodine. Performance was close to maximal over a pH range of 2–10. Capacity was reduced by ~55% by the addition of cocontaminants nitrate and molybdate, but resistance to suppression was greatly superior to non-modified polyamine resins, clearly seen in dynamic column experiments. The uptake mechanism was investigated spectroscopically and was found to proceed via ligand-exchange, with some in-situ REDOX chemistry occurring, resulting in the formation of Cu(I) and triiodide. The latter was concurrently adsorbed on to the resin and occupied both strong (Cu-associated) and weak (charge-transfer complex formation) binding sites. Thermal decomposition of the loaded resins revealed that the captured iodine was volatised at several different temperatures, according to strength of adsorption, but a large fraction was converted to stable CuI, suggesting a possible pathway towards volume-reduction and immobilisation as a final wasteform

Finding the Balance: Creating an open, sustainable future for OU

Today’s scholars have more publishing options available to them than ever before. In addition to traditional publishing venues, open publishing has become a viable and practicable option for communicating research to ever broadening audiences. This breadth of publishing options focuses new attention on the way business models, accessibility, copyright and intellectual property, and research dissemination are envisioned. Moreover, these considerations have important and pressing implications for OU faculty members and graduate students who are authors, readers, reviewers, editors, society associates, and advisory board members dependent upon effective scholarly communication for professional development and advancement. Scholars are on the cusp of a transformative shift toward a more sustainable system of scholarly communication. In 2019 the University Libraries Committee convened a Scholarly Communication Taskforce to examine these issues. The Taskforce met during the 2019-2020 and will continue their work through the spring of 2022. The Taskforce has met monthly to discuss selected readings and how these scholarly communication topics will effect their colleagues and students in their colleges and departments.The Taskforce's work culminated in this report "Finding the Balance: Creating an Open Sustainable Future for OU," to be presented to the OU community. For more information, visit the Taskforce website at https://bit.ly/SCTFReport.N

Dynamic nuclear polarization and spin-diffusion in non-conducting solids

There has been much renewed interest in dynamic nuclear polarization (DNP), particularly in the context of solid state biomolecular NMR and more recently dissolution DNP techniques for liquids. This paper reviews the role of spin diffusion in polarizing nuclear spins and discusses the role of the spin diffusion barrier, before going on to discuss some recent results.Comment: submitted to Applied Magnetic Resonance. The article should appear in a special issue that is being published in connection with the DNP Symposium help in Nottingham in August 200

Measurement of the Hadronic Photon Structure Function F_2^gamma at LEP2

The hadronic structure function of the photon F_2^gamma is measured as a function of Bjorken x and of the factorisation scale Q^2 using data taken by the OPAL detector at LEP. Previous OPAL measurements of the x dependence of F_2^gamma are extended to an average Q^2 of 767 GeV^2. The Q^2 evolution of F_2^gamma is studied for average Q^2 between 11.9 and 1051 GeV^2. As predicted by QCD, the data show positive scaling violations in F_2^gamma. Several parameterisations of F_2^gamma are in agreement with the measurements whereas the quark-parton model prediction fails to describe the data.Comment: 4 pages, 2 figures, to appear in the proceedings of Photon 2001, Ascona, Switzerlan

A measurement of the tau mass and the first CPT test with tau leptons

We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV using tau pairs from Z0 decays. To test CPT invariance we compare the masses of the positively and negatively charged tau leptons. The relative mass difference is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

WW Production Cross Section and W Branching Fractions in e+e- Collisions at 189 GeV

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.Comment: 22 pages, 5 figures, submitted to Phys. Lett.

Genuine Correlations of Like-Sign Particles in Hadronic Z0 Decays

Correlations among hadrons with the same electric charge produced in Z0 decays are studied using the high statistics data collected from 1991 through 1995 with the OPAL detector at LEP. Normalized factorial cumulants up to fourth order are used to measure genuine particle correlations as a function of the size of phase space domains in rapidity, azimuthal angle and transverse momentum. Both all-charge and like-sign particle combinations show strong positive genuine correlations. One-dimensional cumulants initially increase rapidly with decreasing size of the phase space cells but saturate quickly. In contrast, cumulants in two- and three-dimensional domains continue to increase. The strong rise of the cumulants for all-charge multiplets is increasingly driven by that of like-sign multiplets. This points to the likely influence of Bose-Einstein correlations. Some of the recently proposed algorithms to simulate Bose-Einstein effects, implemented in the Monte Carlo model PYTHIA, are found to reproduce reasonably well the measured second- and higher-order correlations between particles with the same charge as well as those in all-charge particle multiplets.Comment: 26 pages, 6 figures, Submitted to Phys. Lett.

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results