Retraction: Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa.

Retraction of 'Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa' by G. Alexander Smith et al., Chem. Commun., 2022, 58, 9064-9067, https://doi.org/10.1039/D2CC03170A.

Production and radiochemistry of antimony-120m: Efforts toward Auger electron therapy with 119Sb.

Targeted Meitner-Auger Therapy (TMAT) has potential for personalized treatment thanks to its subcellular dosimetric selectivity, which is distinct from the dosimetry of ß- and α particle emission based Targeted Radionuclide Therapy (TRT). To date, most clinical and preclinical TMAT studies have used commercially available radionuclides. These studies showed promising results despite using radionuclides with theoretically suboptimal photon to electron ratios, decay kinetics, and electron emission spectra. Studies using radionuclides whose decay characteristics are considered more optimal are therefore important for evaluation of the full potential of Meitner-Auger therapy; 119Sb is among the best such candidates. In the present work, we develop radiochemical purification of 120Sb from irradiated natural tin targets for TMAT studies with 119Sb.

Cyclotron production of 43Sc and 44gSc from enriched 42CaO, 43CaO, and 44CaO targets.

Introduction: 43Sc and 44gSc are both positron-emitting radioisotopes of scandium with suitable half-lives and favorable positron energies for clinical positron emission tomography (PET) imaging. Irradiation of isotopically enriched calcium targets has higher cross sections compared to titanium targets and higher radionuclidic purity and cross sections than natural calcium targets for reaction routes possible on small cyclotrons capable of accelerating protons and deuterons. Methods: In this work, we investigate the following production routes via proton and deuteron bombardment on CaCO3 and CaO target materials: 42Ca(d,n)43Sc, 43Ca(p,n)43Sc, 43Ca(d,n)44gSc, 44Ca(p,n)44gSc, and 44Ca(p,2n)43Sc. Radiochemical isolation of the produced radioscandium was performed with extraction chromatography using branched DGA resin and apparent molar activity was measured with the chelator DOTA. The imaging performance of 43Sc and 44gSc was compared with 18F, 68Ga, and 64Cu on two clinical PET/CT scanners. Discussion: The results of this work demonstrate that proton and deuteron bombardment of isotopically enriched CaO targets produce high yield and high radionuclidic purity 43Sc and 44gSc. Laboratory capabilities, circumstances, and budgets are likely to dictate which reaction route and radioisotope of scandium is chosen.

Copper-Mediated Radiobromination of (Hetero)Aryl Boronic Pinacol Esters.

A copper-mediated radiobromination of (hetero)aryl boronic pinacol esters is described. Cyclotron-produced [76/77Br]bromide was isolated using an anion exchange cartridge, wherein the pre-equilibration and elution solutions played a critical role in downstream deboro-bromination. The bromination tolerates a broad range of functional groups, labeling molecules with ranging electronic and steric effects. Bologically active radiopharmaceuticals were synthesized, including two radiobrominated inhibitors of poly ADP ribose polymerase, a clinically relevant chemotherapeutic target for ovarian, breast, and prostate cancers.

Nanostructured polyvinylpyrrolidone-curcumin conjugates allowed for kidney-targeted treatment of cisplatin induced acute kidney injury.

Acute kidney injury (AKI) leads to unacceptably high mortality due to difficulties in timely intervention and less efficient renal delivery of therapeutic drugs. Here, a series of polyvinylpyrrolidone (PVP)-curcumin nanoparticles (PCurNP) are designed to meet the renal excretion threshold (∼45 kDa), presenting a controllable delivery nanosystem for kidney targeting. Renal accumulation of the relatively small nanoparticles, 89Zr-PCurNP M10 with the diameter between 5 and 8 nm, is found to be 1.7 times and 1.8 times higher than the accumulation of 89Zr-PCurNP M29 (20-50 nm) and M40 (20-50 nm) as revealed by PET imaging. Furthermore, serum creatinine analysis, kidney tissues histology, and tubular injury scores revealed that PCurNP M10 efficiently treated cisplatin-induced AKI. Herein, PCurNP offers a novel and simple strategy for precise PET image-guided drug delivery of renal protective materials.

CO2 laser heating system for in situ radial x-ray absorption at 16-BM-D at the Advanced Photon Source.

We present a portable CO2 laser heating system for in situ x-ray absorption spectroscopy (XAS) studies at 16-BM-D (High Pressure Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory). Back scattering optical measurements are made possible by the implementation of a Ge beamsplitter. Optical pyrometry is conducted in the near-infrared, and our temperature measurements are free of chromatic aberration due to the implementation of the peak-scaling method [A. Kavner and W. R. Panero, Phys. Earth Planet. Inter. 143-144, 527-539 (2004) and A. Kavner and C. Nugent, Rev. Sci. Instrum. 79, 024902 (2008)] and mode scrambling of the input signal. Laser power stabilization is established using electronic feedback, providing a steady power over second timescales [Childs et al., Rev. Sci. Instrum. 91, 103003 (2020)]-crucial for longer XAS collections. Examples of in situ high pressure-temperature extended x-ray absorption fine structure measurements of ZrO2 are presented to demonstrate this new capability.

Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa.

We report a previously unobserved superconducting state of the photosynthesized carbonaceous sulfur hydride (C-S-H) system with a maximum TC of 191(1) K below 100 GPa. The properties of C-S-H are dependent on carbon content, and X-ray diffraction and simulations reveal the system remains molecular-like up to 100 GPa.

A self-determination theory based investigation of life skills development in youth sport.

This study investigated if basic need satisfaction and frustration mediated the associations between autonomy-supportive and controlling coaching behaviours and participants' development of eight different life skills in youth sport. British sports participants (N = 309, Mage = 14.71) completed measures assessing the study variables. Correlational analyses showed that autonomy-supportive coaching behaviours were positively associated with the satisfaction of participants' three basic needs (autonomy, competence, and relatedness) and their development of all eight life skills, whereas controlling coaching behaviours were only positively related to the frustration of participants' three basic needs. Mediational analyses revealed that satisfaction of all three basic needs combined (total need satisfaction) mediated the associations between autonomy-supportive coaching behaviours and participants' development of the eight life skills. Relatedness satisfaction mediated the associations between autonomy-supportive coaching behaviours and participants' development of all eight life skills except for goal setting; autonomy satisfaction mediated the associations between autonomy-supportive coaching behaviours and participants' time management skills; and competence satisfaction mediated the associations between autonomy-supportive coaching behaviours and participants' goal setting and emotional skills. Based on such findings, coaches should look to display autonomy-supportive behaviours that help to satisfy participants' three basic psychological needs and promote their life skills development in sport.

Effects of Attentional Strategies on Novice Dart Throwing, Quiet Eye Duration and Pupillary Responses.

This study examined the effects of focus of attention (FOA) instructions on learning a dart throwing task, quiet eye duration (QED) and pupillary responses. Thirty-six novices (M age = 33.6, SD = 19.7) learned using either (a) internal-focus (arm movement), (b) external-focus (target/dart) or (c) control instructions before completing retention and transfer tests 10 days later. FOA strategies did not significantly benefit dart throwing learning or performance. QED was associated with performance in the transfer task, and pupillary constriction occurred during the QED. The content of FOA instructions may have limited anticipated performance benefits and reduced the FOA influence on QED. Pupillary constriction reflected increased cognitive effort during QED, suggesting an important feature of future precision aiming research.

A High Separation Factor for 165Er from Ho for Targeted Radionuclide Therapy.

Background: Radionuclides emitting Auger electrons (AEs) with low (0.02-50 keV) energy, short (0.0007-40 µm) range, and high (1-10 keV/µm) linear energy transfer may have an important role in the targeted radionuclide therapy of metastatic and disseminated disease. Erbium-165 is a pure AE-emitting radionuclide that is chemically matched to clinical therapeutic radionuclide 177Lu, making it a useful tool for fundamental studies on the biological effects of AEs. This work develops new biomedical cyclotron irradiation and radiochemical isolation methods to produce 165Er suitable for targeted radionuclide therapeutic studies and characterizes a new such agent targeting prostate-specific membrane antigen. Methods: Biomedical cyclotrons proton-irradiated spot-welded Ho(m) targets to produce 165Er, which was isolated via cation exchange chromatography (AG 50W-X8, 200-400 mesh, 20 mL) using alpha-hydroxyisobutyrate (70 mM, pH 4.7) followed by LN2 (20-50 µm, 1.3 mL) and bDGA (50-100 µm, 0.2 mL) extraction chromatography. The purified 165Er was radiolabeled with standard radiometal chelators and used to produce and characterize a new AE-emitting radiopharmaceutical, [165Er]PSMA-617. Results: Irradiation of 80-180 mg natHo targets with 40 µA of 11-12.5 MeV protons produced 165Er at 20-30 MBq·µA-1·h-1. The 4.9 ± 0.7 h radiochemical isolation yielded 165Er in 0.01 M HCl (400 µL) with decay-corrected (DC) yield of 64 ± 2% and a Ho/165Er separation factor of (2.8 ± 1.1) · 105. Radiolabeling experiments synthesized [165Er]PSMA-617 at DC molar activities of 37-130 GBq·µmol-1. Conclusions: A 2 h biomedical cyclotron irradiation and 5 h radiochemical separation produced GBq-scale 165Er suitable for producing radiopharmaceuticals at molar activities satisfactory for investigations of targeted radionuclide therapeutics. This will enable fundamental radiation biology experiments of pure AE-emitting therapeutic radiopharmaceuticals such as [165Er]PSMA-617, which will be used to understand the impact of AEs in PSMA-targeted radionuclide therapy of prostate cancer.

A Third Generation Potentially Bifunctional Trithiol Chelate, Its nat,1XXSb(III) Complex, and Selective Chelation of Radioantimony (119Sb) from Its Sn Target.

The therapeutic potential of the Meitner-Auger- and conversion-electron emitting radionuclide 119Sb remains unexplored because of the difficulty of incorporating it into biologically targeted compounds. To address this challenge, we report the development of 119Sb production from electroplated tin cyclotron targets and its complexation by a novel trithiol chelate. The chelation reaction occurs in harsh solvent conditions even in the presence of large quantities of tin, which are necessary for production on small, low energy (16 MeV) cyclotrons. The 119Sb-trithiol complex has high stability and can be purified by HPLC. The third generation trithiol chelate and the analogous stable natSb-trithiol compound were synthesized and characterized, including by single-crystal X-ray diffraction analyses.

Alternative strategies for the synthesis of [11C]ER176 for PET imaging of neuroinflammation.

[11C]ER176 is a next generation PET radioligand for imaging 18 kDa translocator protein, a biomarker for neuroinflammation. The goal of this work was to investigate alternative strategies for the radiochemical synthesis, purification, and formulation of [11C]ER176. An optimized tri-solvent high-performance liquid chromatography (HPLC) protocol is described to separate the hydro-de-chlorinated byproduct from [11C]ER176. A newly implemented solid phase extraction work-up efficiently removed HPLC solvent while maintaining chemical purity and overall radiochemical yield and purity. This new HPLC purification and final formulation was completed within 40 min, providing 2.7 ± 0.5 GBq of [11C]ER176 at end of synthesis with 1400 ± 300 GBq/µmol molar activity while meeting all specifications for radiopharmaceutical quality control tests for human research use.

Neurofibrillary tau depositions emerge with subthreshold cerebral beta-amyloidosis in down syndrome.

INTRODUCTION: Adults with Down syndrome are genetically predisposed to develop Alzheimer's disease and accumulate beta-amyloid plaques (Aß) early in life. While Aß has been heavily studied in Down syndrome, its relationship with neurofibrillary tau is less understood. The aim of this study was to evaluate neurofibrillary tau deposition in individuals with Down syndrome with varying levels of Aß burden. METHODS: A total of 161 adults with Down syndrome (mean age = 39.2 (8.50) years) and 40 healthy, non-Down syndrome sibling controls (43.2 (12.6) years) underwent T1w-MRI, [C-11]PiB and [F-18]AV-1451 PET scans. PET images were converted to units of standardized uptake value ratios (SUVrs). Aß burden was calculated using the amyloid load metric (AßL); a measure of global Aß burden that improves quantification from SUVrs by suppressing the nonspecific binding signal component and computing the specific Aß signal from all Aß-carrying voxels from the image. Regional tau was assessed using control-standardized AV-1451 SUVr. Control-standardized SUVrs were compared across Down syndrome groups of Aß-negative (A-) (AßL < 13.3), subthreshold A+ (13.3 ≤ AßL < 20) and conventionally A+ (AßL ≥ 20) individuals. The subthreshold A + group was identified as having significantly higher Aß burden compared to the A- group, but not high enough to satisfy a conventional A + classification. RESULTS: A large-sized association that survived adjustment for chronological age, mental age (assessed using the Peabody Picture Vocabulary Test), and imaging site was observed between AßL and AV-1451 within each Braak region (p < .05). The A + group showed significantly higher AV-1451 retention across all Braak regions compared to the A- and subthreshold A + groups (p < .05). The subthreshold A + group showed significantly higher AV-1451 retention in Braak regions I-III compared to an age-matched sample from the A- group (p < .05). DISCUSSION: These results show that even the earliest detectable Aß accumulation in Down syndrome is accompanied by elevated tau in the early Braak stage regions. This early detection of tau can help characterize the tau accumulation phase during preclinical Alzheimer's disease progression in Down syndrome and suggests that there may be a relatively narrow window after Aß accumulation begins to prevent the downstream cascade of events that leads to Alzheimer's disease.

Characterization of actinide resin for separation of 51,52gMn from bulk target material.

We report an extraction chromatography-based method via Actinide Resin for the isolation of radio-manganese from both natural chromium and isotopically enriched iron targets for cyclotron production of 52gMn and 51Mn. For the separation of 52gMn from natCr, a decay-corrected radiochemical yield of 83.7 ± 8.4% was achieved. For 51Mn from 54Fe, a decay-corrected radiochemical yield of 78 ± 11% was achieved. This automatable method efficiently isolates both radionuclides from accelerator target material.

Accelerator Production of Scandium Radioisotopes: Sc-43, Sc-44, and Sc-47.

Scandium radioisotopes are increasingly considered viable radiolabels for targeted molecular imaging (Sc-43, Sc-44) and therapy (Sc-47). Significant technological advances have increased the quantity and quality of available radioscandium in the past decade, motivated in part by the chemical similarity of scandium to therapeutic radionuclides like Lu-177. The production and radiochemical isolation techniques applied to scandium radioisotopes are reviewed, focusing on charged particle and electron linac initiated reactions and using calcium and titanium as starting materials.

Optical and electronic solutions for power stabilization of CO2 lasers.

High pressure-temperature conditions can be readily achieved through the laser-heated diamond anvil cell (LH-DAC). A stable laser source is required for reliable in situ measurements of the sample, as the sample is small with a thermal time constant of the order of microseconds. Here, we show that the power instabilities typical of CO2 gas lasers used in LH-DAC's are ±5% at the second timescale and ∼±50% at the microsecond timescale. We also demonstrate that the pointing instability of the laser requires either a diffuser or an integrating sphere for reliable total power measurements with small sized detectors. We present a simple solution for stabilizing the power of a CO2 gas laser on the second timescale by the direct modulation of the current across the tube and another solution that stabilizes the power to the microsecond timescale by externally modulating the CO2 laser beam. Both solutions can achieve a ±0.3% power stability.

A test of optimal theory on young adolescents' standing long jump performance and motivation.

The OPTIMAL theory of motor learning contends that an external focus of attention (EF), enhanced expectancies (EE), and autonomy support (AS) are key attentional and motivational variables that optimise motor performance. We examined how integrating an EF into EE and AS interventions would impact young adolescents' standing long jump performance and self-efficacy, perceived competence, task effort, task importance and positive affect. Forty-eight participants completed 3 jumps in a baseline, EF (focus on jumping towards the cone), EE-EF (positive social-comparative feedback/high success probability) and AS-EF (self-definition of success) conditions. Both the EF and AS-EF conditions (but not the EE-EF condition) improved jump performance from baseline. The EF, EE-EF and AS-EF conditions improved young adolescents' self-efficacy, perceived competence, task effort and positive affect in comparison to baseline and were predictors of jump performance (as was task importance). However, in the EE-EF condition motivational states improved (from baseline) but this did not translate into performance improvements. The findings show that directing attention to visual external cues both independently and when framed within AS conditions enhanced young adolescents' jump performance and motivation through efficient goal-action coupling. In practice, PE teachers and sports coaches working with young adolescents can support autonomy by allowing self-definition of success using an external cue to enhance effective goal-action coupling, motor performance and motivation.

Beyond visual fixations and gaze behaviour. Using pupillometry to examine the mechanisms in the planning and motor performance of a golf putt.

The present study assessed the potential value of using pupillometry to explore skill level differences in the allocation of attention during planning and performance of a golf putt across three putting conditions of varying complexity. Although numerous studies have reported on skill level differences in performers' visual search behaviours, performance accuracy and quiet eye duration (QE) across a range of performance settings, few have provided an objective measure of the allocation of attention during task performance. Fourteen participants were assigned to two groups [low handicap (LHG) and high handicap (HHG)] completing ten putts in three conditions; right to left (RL), left to right (LR) and straight (ST) from 1.75 m while wearing a mobile eye tracker. Skill based differences in the allocation of attention during green exploration and skill execution were observed. Pupil constriction observed for both groups during the QE period provides evidence of increased workload directly related to the increased motor task precision required in the physical performance of the putt. LHG had significantly more fixations of longer duration than their HHG counterparts. Distinct differences were also evident between skill levels in relation to number of fixations, fixation duration and QE duration on each putting condition. The significantly longer QE duration and larger pupil constrictions exhibited by skilled performers offer evidence of a distinctive concentration of cognitive activity characterised by highly automated processes.

Improved production of 76Br, 77Br and 80mBr via CoSe cyclotron targets and vertical dry distillation.

INTRODUCTION: The radioisotopes of bromine are uniquely suitable radiolabels for small molecule theranostic radiopharmaceuticals but are of limited availability due to production challenges. Significantly improved methods were developed for the production and radiochemical isolation of clinical quality 76Br, 77Br, and 80mBr. The radiochemical quality of the radiobromine produced using these methods was tested through the synthesis of a novel 77Br-labeled inhibitor of poly (ADP-ribose) polymerase-1 (PARP-1), a DNA damage response protein. METHODS: 76Br, 77Br, and 80mBr were produced in high radionuclidic purity via the proton irradiation of novel isotopically-enriched Co76Se, Co77Se, and Co80Se intermetallic targets, respectively. Radiobromine was isolated through thermal chromatographic distillation in a vertical furnace assembly. The 77Br-labeled PARP inhibitor was synthesized via copper-mediated aryl boronic ester radiobromination. RESULTS: Cyclotron production yields were 103 ±â€¯10 MBq∙µA-1∙h-1 for 76Br, 88 ±â€¯10 MBq∙µA-1∙h-1 for 80mBr at 16 MeV and 17 ±â€¯1 MBq∙µA-1∙h-1 for 77Br at 13 MeV. Radiobromide isolation yields were 76 ±â€¯11% in a small volume of aqueous solution. The synthesized 77Br-labeled PARP-1 inhibitor had a measured apparent molar activity up to 700 GBq/µmol at end of synthesis. CONCLUSIONS: A novel selenium alloy target enabled clinical-scale production of 76Br, 77Br, and 80mBr with high apparent molar activities, which was used to for the production of a new 77Br-labeled inhibitor of PARP-1. ADVANCES IN KNOWLEDGE: New methods for the cyclotron production and isolation of radiobromine improved the production capacity of 77Br by a factor of three and 76Br by a factor of six compared with previous methods. IMPLICATIONS FOR PATIENT CARE: Preclinical translational research of 77Br-based Auger electron radiotherapeutics, such as those targeting PARP-1, will require the production of GBq-scale 77Br, which necessitates next-generation, high-yielding, isotopically-enriched cyclotron targets, such as the novel intermetallic Co77Se.