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- ItemCeramic materials for nuclear waste storage*(Trans Tech Publications, 1990) Reeve. KDThe operation of a nuclear power reactor producing 1300 MW of electrical power typically results in the accumulation of around 30 tonnes of spent fuel per annum. The fuel elements are intact but highly radioactive. Many of the isotopic species comprising the one tonne or so of fission products in the spent fuel are short-, medium-_ and/or long-lived beta- or gamma-emitters. In addition, various isotopes of the transuranic elements neptunium, plutonium, americium and curium - amounting typically to 250 kg in the same mass of fuel - have grown in by various nuclear reactions which follow the absorption of fast neutrons by “EU. Most of these transuranics are medium- to long-lived alpha-emitters. Because of its initially very high and then eventually much lower but very long-lived radioactivity, the management of spent fuel is technically and socially challenging in both the short and long term. In the short term, i.e. for several decades, spent fuel is routinely stored in water-filled pools and later may be transferred to air-cooled dry storage vaults. Further management depends on whether or not the fuel is reprocessed to remove most of its reusable uranium and plutonium. Some spent fuel may eventually be disposed of as ‘waste’ in deep geological repositories without ever having been reprocessed. In the reprocessing option, the nuclear waste contains only the residual fission products, the transuranics neptunium, americium and curiumand a very small fraction of the uranium and plutonium. It is widely accepted that this high level waste (HLW) - which is, as produced, a corrosive nitrate solution - must be solidified, perhaps then stored in air-cooled vaults for up to 50-100 years and eventually disposed of by deep geological burial. It is also accepted that the solidified waste form will be, in the broad sense of the term, a ceramic material. The ceramic may be either crystalline, partly crystalline (glass—ceramic) ‘or non-crystalline (glass).
- ItemRadiosynthesis of [123I]N-methyl-4-iododexetimide and [123I]N-methyl-4-iodolevetimide: In vitro and in vivo characterisation of binding to muscarinic receptors in the rat heart(Elsevier, 1996-02) Kassiou, M; Mardon, K; Katsifis, AG; Najdovski, L; Dikic, B; Mattner, F; Lambrecht, RM; Hicks, RJ; Eu,P; Loc'h, C[123I]N-methyl-4-iododexetimide, [123I]MIDEX, and its pharmacologically inactive enantiomer [123I]N-methyl-4-iodolevetimide, [123I]MILEV were prepared via electrophilic iododesilylation using Chloramine-T as oxidising agent followed by N-methylation using methyl iodide. The radiotracers were purified with semi-preparative HPLC with radiochemical yields of 80 ± 11% (n = 6). The average time of synthesis was 100 min with specific activity >2000 Ci/mmol. In vitro, the binding of [123I]MIDEX, after addition of carrier, measured on homogenates of rat atrium was Bmax = 4.5 ± 0.4 pmol/mg protein, Kd = 3.3 ± 0.2 nM while in the ventricle Bmax = 2.3 ± 0.2 pmol/mg protein, Kd = 4.0 ± 1.4 nM. In vitro, the binding of [123I]MILEV was non-specific. The in vivo biodistribution of [123I]MIDEX showed high uptake in the atrium (3.2% ID/g) and left and right ventricles (2.2, 2.5% ID/g respectively) at 5 min followed by clearance. High heart-to-lung and moderate liver-to-lung ratios were obtained during 60 min. Radioactivity in the atrium and ventricles was reduced by pre-administration of the m-AChR antagonist MQNB (1 mg/kg). Pretreatment of rats with other m-AChR ligands, pirenzapine (M1), methoctramine (M2) and 4-DAMP (M3) also resulted in reduction of [123I]MIDEX uptake with methoctramine being the most potent. [123I]MIDEX distribution in the rat heart was not significantly inhibited by pre-administration of selective adrenergic drugs. The uptake was highly stereoselective since the inactive enantiomer, [123I]MILEV, demonstrated very low myocardial retention. The stability of [123I]MIDEX was evaluated by performing a metabolite study on atrium samples which revealed unchanged radiotracer 60 min postinjection. These results suggest that [123I]MIDEX may be a useful single photon agent for in vivo imaging of myocardial m-AChR in humans with [123I]MILEV offering the potential of assessing non-specific binding of the active tracer. © 1996 Published by Elsevier Inc.
- Item[166Dy]dysprosium/[166Ho]holmium in vivo generator(Elsevier, 1995-08) Smith, SV; Di Bartolo, N; Mirzadeh, S; Lambrecht, RM; Knapp, FF; Hetherington, ELA novel approach for the delivery of 166Ho (t1/2 = 26.6 h) to tissue is via the in vivo decay of its 81.5 h parent, 166Dy-an in vivo generator system. A critical question for the in vivo 166Dy/166Ho generator system is whether translocation of the daughter nucleus occurs. The in vitro and in vivo integrity of the [166Dy]Dy/166Ho-DTPA complex was investigated and results indicated that no translocation of the daughter nucleus occurs subsequent to beta- decay of 166Dy. Biodistribution studies of [166Dy]Dy-DTPA showed that the ratio of 166Dy/166Ho in bone remains constant (+/- 7%) over a 20 h period, indicating no significant in vivo loss of 166Ho from the complex. Increasing the in vivo residence time of [166Dy]Dy-DTPA complex attached to HSA gave similar results. © 1995 Published by Elsevier Ltd
- ItemOxidative damage to biomimetic membrane systems: In situ Fe(II)/ascorbate initiated oxidation and incorporation of synthetic oxidized phospholipids(American Chemical Society (ACS), 2015-10-30) Knobloch, JJ; Nelson, ARJ; Köper, I; James, M; McGillivray, DJDamage to cellular membranes from oxidative stress has been implicated in aging related diseases. We report the effects of oxidative damage on the structure and properties of biomimetic phospholipid membrane systems. Two oxidation methods were used, in situ oxidation initiated using Fe(II) and ascorbate, and the incorporation of a synthetic "oxidized" phospholipid, PoxnoPC, into biomimetic membranes. The biomimetic systems employed included multibilayer stacks, tethered bilayers, and phospholipid monolayers studied using a combination of reflectometry, attenuated total reflection infrared spectroscopy, electrochemical impedance spectroscopy, and neutron diffraction. We show that oxidation with Fe(II) and ascorbate caused an increase in the order of the membrane, attributed to cross-linking of the phospholipids, and a change in the electrical permeability of the membrane, but no significant impact on the thickness or completeness of the membrane. Incorporation of PoxnoPC, on the other hand, had a larger impact on the structure of the membrane. Inversion of the aldehyde-terminated truncated sn-2 chain of PoxnoPC into the head group region was observed, along with a slight decrease in the thickness and order of the membrane. © 2015 American Chemical Society.
- ItemDurable integrated K‐metal anode with enhanced mass transport through potassiphilic porous interconnected mediator(Wiley, 2023-06-15) Zhao, LK; Gao, XW; Mu, JJ; Luo, WB; Liu, ZM; Sun, ZH; Gu, QF; Li, FK‐metal batteries have become one of the promising candidates for the large‐scale energy storage owing to the virtually inexhaustible and widely potassium resources. The uneven K+ deposition and dendrite growth on the anode causes the batteries prematurely failure to limit the further application. An integrated K‐metal anode is constructed by cold‐rolling K metal with a potassiphilic porous interconnected mediator. Based on the experimental results and theoretical calculations, it demonstrates that the potassiphilic porous interconnected mediator boosts the mass transportation of K‐metal anode by the K affinity enhancement, which decreases the concentration polarization and makes a dendrite‐free K‐metal anode interface. The interconnected porous structure mitigates the internal stress generated during repetitive deposition/stripping, enabling minimized the generation of electrode collapse. As a result, a durable K‐metal anode with excellent cycling ability of exceed 1, 000 h at 1 mA cm−2/1 mAh cm−2 and lower polarization voltage in carbonate electrolyte is obtained. This proposed integrated anode with fast K+ kinetics fabricated by a repeated cold rolling and folding process provides a new avenue for constructing a high‐performance dendrites‐free anode for K‐metal batteries. © 1999-2025 John Wiley & Sons, Inc or related companies.