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Browsing by Author "Zhang, B"

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[18F]Ethenesulfonyl fluoride as a practical radiofluoride relay reagent
(John Wiley & Sons, Inc, 2019-04-11) Zhang, B; Fraser, BH; Klenner, MA; Chen, Z; Liang, SH; Massi, M; Robinson, AJ; Pascali, G
Fluorine-18 is the most utilized radioisotope in positron emission tomography (PET), but the wide application of fluorine-18 radiopharmaceuticals is hindered by its challenging labelling conditions. As such, many potentially important radiotracers remain underutilized. Herein, we describe the use of [18F]ethenesulfonyl fluoride (ESF) as a novel radiofluoride relay reagent that allows radiofluorination reactions to be performed in minimally equipped satellite nuclear medicine centres. [18F]ESF has a simple and reliable production route and can be stored on inert cartridges. The cartridges can then be shipped remotely and the trapped [18F]ESF can be liberated by simple solvent elution. We have tested 18 radiolabelling precursors, inclusive of model and clinically used structures, and most precursors have demonstrated comparable radiofluorination efficiencies to those obtained using a conventionally dried [18F]fluoride source. © 2019 Wiley-VCH Verlag GmbH & Co.
Author Correction: A one-third magnetization plateau phase as evidence for the Kitaev interaction in a honeycomb-lattice antiferromagnet
(Springer Nature, 2023-09-10) Shangguan, Y; Bao, S; Dong, ZY; Xi, N; Gao, YP; Ma, Z; Wang, W; Qi, Z; Zhang, S; Huang, Z; Liao, J; Zhao, X; Zhang, B; Cheng, S; Xu, H; Yu, DH; Mole, RA; Murai, N; Ohira-Kawamura, S; He, LH; Hao, J; Yan, QB; Song, F; Li, W; Yu, SL; Li, JX; Wen, JS
Correction to: Nature Physics, published online 25 September 2023. In the version of the article initially published, the affiliation of Zhen Ma, now reading School of Materials Science and Engineering, Hubei Normal University, Huangshi, China, appeared incorrectly. This has been updated in the HTML and PDF versions of the article. n the version of the article initially published, the affiliation of Zhen Ma, now reading School of Materials Science and Engineering, Hubei Normal University, Huangshi, China, appeared incorrectly. This has been updated in the HTML and PDF versions of the article. © 2024 Springer Nature Limited.
Effect of rhenium(i) complexation on aza-Michael additions to 5-amino-1,10-phenanthroline with [18F]ethenesulfonyl fluoride towards PET optical tracer development
(CSIRO Publishing, 2019-01-14) Klenner, MA; Pascali, G; Zhang, B; Ciancaleoni, G; Massi, M; Fraser, BH
Conjugations with the recently developed [18F]ethenesulfonyl fluoride ([18F]ESF) were performed on 5-amino-1,10-phenanthroline, in its free form and coordinated to a rhenium(i) tricarbonyl complex, as a means of radiosynthesizing dual-modal optical and positron emission tomography (PET) tracers. The Michael-donating ability of the aromatic amine was noticeably perturbed on coordination with the rhenium(i) centre, resulting in decreased radiochemical yields from 34 %, in the case of the free ligand, to 1 %. We attribute the decreased nucleophilicity of the amine to metal deactivation from the electron-withdrawing feature of the rhenium(i) tricarbonyl centre, based on spectroscopic and computational evidence, thus highlighting this effect as a crucial parameter in designing late-stage metal coordination methods employing related aza-Michael additions. Photophysical analyses were also performed on the ESF-conjugated rhenium(i) complex, exhibiting a longer decay lifetime from the triplet metal-to-ligand charge transfer excited state when compared with the non-conjugated analogue. © CSIRO 1996-2021
Evaluate transport processes in MERRA driven chemical transport models using updated 222Rn emission inventories and global observations
(AGU, 2015-12-14) Zhang, B; Liu, HY; Crawford, J; Fairlie, TD; Chen, G; Chambers, SD; Kang, CH; Williams, AG; Zhang, K; Considine, DB; Sulprizio, MP; Yantosca, RM
Convective and synoptic processes play a major role in determining the transport and distribution of trace gases and aerosols in the troposphere. The representation of these processes in global models (at ~100-1000 km horizontal resolution) is challenging, because convection is a sub-grid process and needs to be parameterized, while synoptic processes are close to the grid scale. Depending on the parameterization schemes used in climate models, the role of convection in transporting trace gases and aerosols may vary from model to model. 222Rn is a chemically inert and radioactive gas constantly emitted from soil and has a half-life (3.8 days) comparable to synoptic timescale, which makes it an effective tracer for convective and synoptic transport. In this study, we evaluate the convective and synoptic transport in two chemical transport models (GMI and GEOS-Chem), both driven by the NASA’s MERRA reanalysis. Considering the uncertainties in 222Rn emissions, we incorporate two more recent scenarios with regionally varying 222Rn emissions into GEOS-Chem/MERRA and compare the simulation results with those using the relatively uniform 222Rn emissions in the standard model. We evaluate the global distribution and seasonality of 222Rn concentrations simulated by the two models against an extended collection of 222Rn observations from 1970s to 2010s. The intercomparison will improve our understanding of the spatial variability in global 222Rn emissions, including the suspected excessive 222Rn emissions in East Asia, and provide useful feedbacks on 222Rn emission models. We will assess 222Rn vertical distributions at different latitudes in the models using observations at surface sites and in the upper troposphere and lower stratosphere. Results will be compared with previous models driven by other meteorological fields (e.g., fvGCM and GEOS4). Since the decay of 222Rn is the source of 210Pb, a useful radionuclide tracer attached to submicron aerosols, improved understanding of emissions and transport of 222Rn will provide insights into the transport, distribution, and wet deposition of 210Pb aerosols.
Evaluation of the antidepressant therapeutic potential of isocyanine and pseudoisocyanine analogues of the organic cation decynium-22
(Elsevier B. V., 2017-09-08) Krause-Heuer, AM; Fraser-Spears, R; Dobrowolski, JC; Ashford, ME; Wyatt, NA; Roberts, MP; Gould, GG; Cheah, WC; Ng, CKL; Bhadbhade, MM; Zhang, B; Greguric, ID; Wheate, NJ; Kumar, N; Koek, W; Callaghan, PD; Daws, LC; Fraser, BH
Antidepressant-like activity Herein we describe the synthesis and evaluation of antidepressant properties of seven analogues (1–7) of the low affinity/high capacity transporter blocker decynium-22 (D-22). All analogues (1–7) were synthesized via base promoted coupling reactions between N-alkylated-2-methylquinolinium iodides or N-alkylated-4-methylquinolinium iodides and electrophilic N-alkylated-2-iodoquinolinium iodides. All final compounds were purified by re-crystallization or preparative HPLC and initial evaluation studies included; 1) screening for in vitro α1-adrenoceptor activity (a property that can lead to unwanted side-effects), 2) measuring antidepressant-like activity in a mouse tail suspension test (TST), and 3) measuring effects upon mouse locomotion. The results showed some analogues have lower affinities at α1-adrenoceptors compared to D-22 and showed antidepressant-like activity without the need for co-administration of SSRIs. Additionally, many analogues did not affect mouse locomotion to the same extent as D-22. Plans for additional evaluations of these promising analogues, including measurement of antidepressant-like activity with co-administration of selective serotonin re-uptake inhibitors (SSRIs), are outlined. © 2017 Elsevier B.V.
A fluorine-18 radiolabeling method enabled by rhenium(I) complexation circumvents the requirement of anhydrous conditions
(John Wiley & Sons, Inc, 2017-03-22) Klenner, MA; Pascali, G; Zhang, B; Sia, TR; Spare, LK; Krause-Heuer, AM; Aldrich-Wright, JR; Greguric, ID; Guastella, AJ; Massi, M; Fraser, BH
Azeotropic distillation is typically required to achieve fluorine-18 radiolabeling during the production of positron emission tomography (PET) imaging agents. However, this time-consuming process also limits fluorine-18 incorporation, due to radioactive decay of the isotope and its adsorption to the drying vessel. In addressing these limitations, the fluorine-18 radiolabeling of one model rhenium(I) complex is reported here, which is significantly improved under conditions that do not require azeotropic drying. This work could open a route towards the investigation of a simplified metal-mediated late-stage radiofluorination method, which would expand upon the accessibility of new PET and PET-optical probes. © 2017 John Wiley & Sons, Inc
Gamma radiation effects on the performance of FIR-based fiber-optic temperature sensors
(Institute of Electrical and Electronics Engineers, 2019-11-02) Fan, D; Xiao, G; Chu, Y; Ma, Z; Wei, S; Zhang, B; Tian, Y; Fu, X; Obbard, EG; Davies, JB; Luo, Y; Peng, GD
The gamma radiation effect on the performance of fluorescence intensity ratio-based fiber-optic temperature sensors is studied. The results indicate such temperature sensors are promising for integration in gamma radiation environment.
A novel [18F]fluoride relay reagent for radiofluorination reactions
(John Wiley & Sons, Inc, 2019-05-26) Zhang, B; Fraser, BH; Klenner, MA; Chen, Z; Liang, SH; Massi, M; Robinson, AJ; Pascali, G
Objectives Fluorine‐18 is the most utilized radioisotope in Positron Emission Tomography (PET), but the wide application of fluorine‐18 radiopharmaceuticals is hindered by its challenging labelling conditions. This necessitates production at centralized PET centres with highly specialized equipment including cyclotrons, hot cells, synthesizers, and HPLC capabilities, which ultimately limit the availability of fluorine‐18 tracers to those whose production has a large marketing scale (e.g., [18F]FDG). As such, many potentially important leads remain underutilized. Herein, we describe the use of [18F]ethenesulfonyl fluoride (ESF) as a novel radiofluoride relay reagent that allows radiofluorination reactions to be performed in minimally equipped satellite nuclear medicine centres (Figure 1). Methods [18F]ESF was produced from 2,4,6‐trichlorophenylethenesulfonate using a microfluidic system and was stored on inert cartridges. The cartridges could be shipped remotely where trapped [18F]ESF was liberated by chosen solvent to a vial containing precursor and additives. The reaction mixture was then stirred and heated using a heating block. Reaction conditions including temperature, time, precursor concentration, and additives were optimised, and the radiochemical yields (RCYs) were compared with those for traditional [18F]fluoride method. Results We found that conditions of 1 mg/mL precursor, 0.5 mg/mL tetraethylammonium bicarbonate as additive, temperature of 100°C, and time of 15 min were useful to assess radiofluorination scope on commercially available precursors. The obtained RCYs were compared with those generated from traditional dried [18F]fluoride source and no statically significant difference was observed for most precursors. Some differences on RCYs, both positive and negative, were noted when novel type of precursors (i.e., boronic acids, iodonium ylides) were tested. Conclusions We have developed a method to perform radiofluorinations using a new radiofluoride relay reagent, [18F] ESF. Such method reduces the reaction equipment needed, in the simplest case to a simple heating block, single‐use vials and magnetic stir bar. Notably, this new process is not only compatible with typical commercial precursors, but also feasible to accommodate emerging precursors with novel leaving groups. © 2019 The Authors
Novel fluorinated 8-hydroxyquinoline based metal Ionophores for exploring the metal hypothesis of alzheimer’s disease
(American Chemical Society, 2015-08-10) Liang, SH; Southon, AG; Fraser, BH; Krause-Heuer, AM; Zhang, B; Shoup, TM; Lewis, R; Volitakis, I; Han, Y; Greguric, ID; Bush, AI; Vasdev, Y
Zinc, copper, and iron ions are involved in amyloid-beta (Aβ) deposition and stabilization in Alzheimer’s disease (AD). Consequently, metal binding agents that prevent metal-Aβ interaction and lead to the dissolution of Aβ deposits have become well sought therapeutic and diagnostic targets. However, direct intervention between diseases and metal abnormalities has been challenging and is partially attributed to the lack of a suitable agent to determine and modify metal concentration and distribution in vivo. In the search of metal ionophores, we have identified several promising chemical entities by strategic fluorination of 8-hydroxyquinoline drugs, clioquinol, and PBT2. Compounds 15–17 and 28–30 showed exceptional metal ionophore ability (6–40-fold increase of copper uptake and >2-fold increase of zinc uptake) and inhibition of zinc induced Aβ oligomerization (EC50s < ∼5 μM). These compounds are suitable for further development as drug candidates and/or positron emission tomography (PET) biomarkers if radiolabeled with 18F. © 2015 American Chemical Society
Novel low-strain layered/rocksalt intergrown cathode for high-energy Li-ion batteries
(American Chemical Society (ACS), 2023-11-16) Xu, L; Chen, S; Su, Y; Shen, X; He, J; Avdeev, M; Kan, WH; Zhang, B; Fan, W; Chen, L; Cao, D; Lu, Y; Wang, L; Wang, M; Bao, L; Zhang, L; Li, N; Wu, F
Both layered- and rocksalt-type Li-rich cathode materials are drawing great attention due to their enormous capacity, while the individual phases have their own drawbacks, such as great volume change for the layered phase and low electronic and ionic conductivities for the rocksalt phase. Previously, we have reported the layered/rocksalt intergrown cathodes with nearly zero-strain operation, while the use of precious elements hinders their industrial applications. Herein, low-cost 3d Mn4+ ions are utilized to partially replace the expensive Ru5+ ions, to develop novel ternary Li-rich cathode material Li1+x[RuMnNi]1-xO2. The as-designed Li1.15Ru0.25Mn0.2Ni0.4O2 is revealed to have a layered/rock salt intergrown structure by neutron diffraction and transmission electron microscopy. The as-designed cathode exhibits ultrahigh lithium-ion reversibility, with 0.86 (231.1 mAh g-1) out of a total Li+ inventory of 1.15 (309.1 mAh g-1). The X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectra further demonstrate that the high Li+ storage of the intergrown cathode is enabled by leveraging cationic and anionic redox activities in charge compensation. Surprisingly, in situ X-ray diffraction shows that the intergrown cathode undergoes extremely low-strain structural evolution during the charge-discharge process. Finally, the Mn content in the intergrown cathodes is found to be tunable, providing new insights into the design of advanced cathode materials for high-energy Li-ion batteries. © 2024 American Chemical Society.
Rhenium complexation‐dissociation strategy for fluorine‐18 labelling of bidentate PET ligands
(John Wiley & Sons, Inc, 2019-05-26) Klenner, MA; Pascali, G; Zhang, B; Massi, M; Fraser, BH
Objectives Pursuant to the discovery that rhenium complexation promotes fluorine‐18 radiolabelling of 1,10‐phenanthroline systems under low temperature, quasi‐aqueous conditions, which circumvent the need for azeotropic drying, we expanded our investigation towards thermal decomplexation strategies to improve the radiosynthesis of similar pyridinyl bidentate tracers. Methods Thirty‐eight compounds were synthesised based upon chloro, bromo, nitro, and fluoro substitutions of 1,10‐ phenanthroline, 2,2’‐bipyridine and 8‐hydroxyquinoline structures and their respective rhenium tricarbonyl chloride complexes. Each of these compounds, save for the nonradioactive fluoro substituted standards, were reacted (>n = 8) under microfluidic conditions with tetraethyl ammonium [18F]fluoride in anhydrous DMSO solvent with increasing reaction temperatures ranging from 50°C to 190°C in 20°C increments. All other parameters such as the precursor quantity, radioactivity, and flow rate/reaction time were kept constant (0.08 μmol, 29 ± 10 MBq, 20 μL·min−1/47 s, respectively). Radiochemical yields (RCYs) for each reaction were then calculated from the Radio‐HPLC peak integrations of the non‐isolated products. Results High RCYs were observed for the [18F]fluoride substitution of rhenium complexed 1,10‐phenanthroline structures (up to 91%) at temperatures ≤90°C, which could prove useful as a novel method for producing PET‐optical tracers given the optical emission properties of rhenium. Good RCYs were also observed for the 2,2’‐bipyridine rhenium complexes, peaking at 84% at 130°C in one example, which then dissociated to form the radiolabelled ligand in 82% RCY at a higher temperature of 190°C, as shown in Figure 1. Radiolabelling of these ligands was unsuccessful under conventional conditions using dry [18F]fluoride, thus establishing rhenium complexation‐dissociation as a novel method for radiolabelling. The fluorine‐18 labelling of 8‐ hydroxyquinoline structures was also tested as a means of improving the radiosynthesis of Alzheimer's disease imaging PET tracers such as [18F]CABS13. While preliminary rhenium complexation‐dissociation experiments have not yet improved on the radiosynthesis of [18F]CABS13 (5% RCY of ligand & 18% RCY of rhenium complex vs 19±5% RCY of ligand in literature), such experiments have enabled the radiosynthesis of related structures, which could not be radiolabelled under conventional conditions using dry [18F]fluoride (eg, [18F]5‐ fluoro‐8‐hydroxyquinoline). Conclusions We report a novel radiofluorination method utilising the rhenium complexation of pyridinyl bidentate structures. This method facilitates radiolabelling of certain analogues of 2,2’‐bipyridine and 8‐hydroxyquinoline structures, which do not radiolabel under conventional conditions. Investigations into monopyridine structures and the development of milder methods of decomplexation are currently ongoing. © 2019 The Authors
Rhenium(i) complexation–dissociation strategy for synthesising fluorine-18 labelled pyridine bidentate radiotracers
(Royal Society of Chemistry, 2020-02-28) Klenner, MA; Zhang, B; Ciancaleoni, G; Howard, JK; Maynard-Casely, HE; Clegg, JK; Massi, M; Fraser, BH; Pascali, G
A novel fluorine-18 method employing rhenium(I) mediation is described herein. The method was found to afford moderate to high radiochemical yields of labelled rhenium(I) complexes. Subsequent thermal dissociation of the complexes enabled the radiosynthesis of fluorine-18 labelled pyridine bidentate structures which could not be radiofluorinated hitherto. This rhenium(I) complexation–dissociation strategy was further applied to the radiosynthesis of [18F]CABS13, an Alzheimer's disease imaging agent, alongside other 2,2′-bipyridine, 1,10-phenanthroline and 8-hydroxyquinoline labelled radiotracers. Computational modelling of the reaction mechanism suggests that the efficiency of rhenium(I) activation may be attributed to both an electron withdrawal effect by the metal center and the formation of an acyl fluoride intermediate which anchors the fluoride subsequent to nucleophilic addition. © The Royal Society of Chemistry 2020 - Open Access
Simulation of radon-222 with the GEOS-Chem global model: emissions, seasonality, and convective transport
(Copernicus Publications, 2021-02-10) Zhang, B; Liu, HY; Crawford, JH; Chen, G; Fairlie, TD; Chambers, SD; Kang, CH; Williams, AG; Zhang, K; Considine, DB; Sulprizio, MP; Yantosca, RM
Radon-222 (222Rn) is a short-lived radioactive gas naturally emitted from land surfaces and has long been used to assess convective transport in atmospheric models. In this study, we simulate 222Rn using the GEOS-Chem chemical transport model to improve our understanding of 222Rn emissions and surface concentration seasonality and characterize convective transport associated with two Goddard Earth Observing System (GEOS) meteorological products, the Modern-Era Retrospective analysis for Research and Applications (MERRA) and GEOS Forward Processing (GEOS-FP). We evaluate four global 222Rn emission scenarios by comparing model results with observations at 51 surface sites. The default emission scenario in GEOS-Chem yields a moderate agreement with surface observations globally (68.9 % of data within a factor of 2) and a large underestimate of winter surface 222Rn concentrations at Northern Hemisphere midlatitudes and high latitudes due to an oversimplified formulation of 222Rn emission fluxes (1 atom cm−2 s−1 over land with a reduction by a factor of 3 under freezing conditions). We compose a new global 222Rn emission scenario based on Zhang et al. (2011) and demonstrate its potential to improve simulated surface 222Rn concentrations and seasonality. The regional components of this scenario include spatially and temporally varying emission fluxes derived from previous measurements of soil radium content and soil exhalation models, which are key factors in determining 222Rn emission flux rates. However, large model underestimates of surface 222Rn concentrations still exist in Asia, suggesting unusually high regional 222Rn emissions. We therefore propose a conservative upscaling factor of 1.2 for 222Rn emission fluxes in China, which was also constrained by observed deposition fluxes of 210Pb (a progeny of 222Rn). With this modification, the model shows better agreement with observations in Europe and North America (> 80 % of data within a factor of 2) and reasonable agreement in Asia (close to 70 %). Further constraints on 222Rn emissions would require additional concentration and emission flux observations in the central United States, Canada, Africa, and Asia. We also compare and assess convective transport in model simulations driven by MERRA and GEOS-FP using observed 222Rn vertical profiles in northern midlatitude summer and from three short-term airborne campaigns. While simulations with both GEOS products are able to capture the observed vertical gradient of 222Rn concentrations in the lower troposphere (0–4 km), neither correctly represents the level of convective detrainment, resulting in biases in the middle and upper troposphere. Compared with GEOS-FP, MERRA leads to stronger convective transport of 222Rn, which is partially compensated for by its weaker large-scale vertical advection, resulting in similar global vertical distributions of 222Rn concentrations between the two simulations. This has important implications for using chemical transport models to interpret the transport of other trace species when these GEOS products are used as driving meteorology. © Author(s) 2021.
Sulfur - fluorine bond in PET radiochemistry
(BioMed Central Ltd, 2017-07-17) Pascali, G; Matesic, L; Zhang, B; King, AT; Robinson, AJ; Ung, AT; Fraser, BH
The importance of the sulfur-fluorine bond is starting to increase in modern medicinal chemistry literature. This is due to a better understanding of the stability and reactivity of this moiety depending on the various oxidation states of sulfur. Furthermore, several commercial reagents used for mild and selective fluorination of organic molecules are based on the known reactivity of S-F groups. In this review, we will show how these examples are translating into the 18F field, both for use as stable tags in finished radiopharmaceuticals and as mildly reactive fluoride-relay intermediates. Finally, we also discuss current opportunities where examples of non-radioactive S-F applications/chemistry may be translated into future 18F radiochemistry applications. © The Authors - Creative Commons Attribution 4.0
Synthesis, bioconjugation and stability studies of [18F]ethenesulfonyl fluoride
(John Wiley & Sons, Inc, 2018-06-20) Zhang, B; Pascali, G; Wyatt, NA; Matesic, L; Klenner, MA; Sia, TR; Guastella, AJ; Massi, M; Robinson, AJ; Fraser, BH
Fluorine-18 labelled prosthetic groups (PGs) are often necessary for radiolabelling sensitive biological molecules such as peptides and proteins. Several shortcomings, however, often diminish the final yield of radiotracer. In an attempt to provide higher yielding and operationally efficient tools for radiolabelling biological molecules, we describe herein the first radiochemical synthesis of [18F]ethenesulfonyl fluoride ([18F]ESF) and its Michael conjugation with amino acids and proteins. The synthesis of [18F]ESF was optimised using a microfluidic reactor under both carrier-added (c.a.) and no-carrier-added (n.c.a.) conditions, affording, in a straightforward procedure, 30-50% radiochemical yield (RCY) for c.a. [18F]ESF and 60-70% RCY for n.c.a. [18F]ESF. The conjugation reactions were performed at room temperature using 10 mg/mL precursor in aqueous/organic solvent mixtures for 15 min. The radiochemical stability of the final conjugates was evaluated in injectable formulation and rat serum, and resulted strongly substrate dependent and generally poor in rat serum. Therefore, in this work we have optimised a straightforward synthesis of [18F]ESF and its Michael conjugation with model compounds, without requiring chromatographic purification. However, given the general low stability of the final products, further studies will be required for improving conjugate stability, before assessing the use of this PG for PET imaging. © 2018 John Wiley & Sons, Inc.

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