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Radiosynthesis 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.
[166Dy]dysprosium/[166Ho]holmium in vivo generator
(Elsevier, 1995-08) Smith, SV; Di Bartolo, N; Mirzadeh, S; Lambrecht, RM; Knapp, FF; Hetherington, EL
A 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
Oxidative 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, DJ
Damage 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.
Durable 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, F
K‐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.
Massive anionic fluorine substitution two-dimensional δ-MnO2 nanosheets for high-performance aqueous zinc-ion battery
(Elsevier, 2023-11-30) Wang, D; Liu, ZM; Gao, XW; Gu, QF; Zhao, LK; Luo, WB
As one of the most promising materials for rechargeable aqueous zinc ion batteries (AZIBs), manganese oxide (δ-MnO2) need overcome the fatal limitations of structural instability and manganese dissolution for future practical application. Crystal high-orientated two-dimensional δ-MnO2 nanosheets with massive anionic fluorine were synthesized by a lava method with quenching treatment. When employed as a cathode material for zinc ion batteries, it exhibits a long cycling lifespan and high multiplicity performance. The fluorine atoms substitution can not only stabilize the manganese‑oxygen octahedron [MnO6] structure by introducing fluorine‑manganese chemical bonding, but also regulate the Mn3+/Mn4+ ratio by increasing the Mn3+ concentration content. Meanwhile, the obtained high-orientated 2D nanosheets structure can accelerate the ions kinetic behaviors for high rate electrochemical performance by shortening the ion translation and increasing the electronic conductivity. The optimized δ-MnO2 nanosheets exhibit a superior electrochemical performance of 288 mAh g−1 at current densities of 100 mA g−1. An excellent cycling lifespan up to 96 % capacity retention is indicated as well after 200 cycles at a current density of 200 mA g−1. This element doping strategy by molten salt quenching method has the benefits of simple synthesis steps and high yield with high economic efficiency. © 2023 Elsevier Ltd.

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