The radionuclide 198Au, with a half-life of 2.7 days, emits γ radiation ideal for diagnostic purposes and generates β- particles suitable for effective cancer radiotherapy, making it a perfect nuclide for "theranostics". However, the application of coordination compounds of Au(I)/Au(III) in medicine is limited by their instability in vivo. Here, we explore N-heterocyclic carbene (NHC) organometallic chemistry to stabilize 198Au(I) in radiopharmaceuticals. Thus, Au(I) NHC compounds featuring different scaffolds were selected for 198Au radiolabeling. Eventually, two compounds featuring imidazole (AuNHC-1) and theophylline (AuTMX2) scaffolds were successfully radiolabeled (radiochemical purity = 92.9% and 40.2%, respectively). Instead, two peptidic Au(I) benzimidazolylidene derivatives, capable of blood-brain barrier translocation in vitro, were subjected to ligand exchange reactions under the applied radiolabeling conditions. The obtained proof-of-concept results showed that NHCs are suitable ligands to achieve isotope exchange in Au(I) complexes. Overall, our work reveals the still untapped potential of organometallic chemistry in radiopharmaceutical design.

Radiopharmaceuticals offer targeted treatment by combining diagnostic or therapeutic radionuclides with biologically active molecules. Auranofin is the only Food and Drug Administration (FDA) approved gold(I) complex, originally developed for the treatment of rheumatoid arthritis. Recent evidence has highlighted its potential as an anticancer agent due to its ability to disrupt redox signaling, inhibit thioredoxin reductase, and impair glycolytic metabolism. This study aims to incorporate the true theranostic radionuclide 198Au into the Auranofin scaffold and evaluate its impact in-vitro on cancer cells. Carrier-added (c.a.)198Au was produced via neutron activation of 197Au and subsequently converted into c.a. H [198Au] [AuCl₄]. Downscaled synthetic protocols were developed to sequentially generate c.a. [198Au] [Au(tht)Cl], [198Au] [Au(PEt₃)Cl], and [198Au]Auranofin. Radiochemical purity was evaluated using radio-high performance liquid chromatography, and in vitro stability was assessed in human serum albumin (HSA) over 72 h. Cytotoxic and metabolic activity were investigated in MCF7 and PC3 cancer cell lines using the cell viability assay 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT assay) and hexokinase assay, respectively. [198Au]Auranofin (c.a.) was obtained with a yield of 57.0 ± 3.2

Quantum electrodynamics has been tested to accuracies below the parts-per-trillion level in light-mass systems. However, tests in heavy-mass systems with a large nuclear charge have not yet reached similar accuracy. Here we report the hyperfine-structure splitting in the 1s ground state of radioactive hydrogen-like 208Bi82+. We produced the isotope in a nuclear reaction and injected the beam into a storage ring to perform laser spectroscopy on samples of 105 ions of Bi82+ that have only a single remaining electron, which experiences extreme magnetic-field strengths. Our result for the hyperfine splitting is in excellent agreement with the most accurate prediction based on a combination of quantum electrodynamics calculations with an empirical treatment of the hyperfine-structure anomaly ratio extracted from laser spectroscopy on neutral atoms of 209Bi and 208Bi. This achievement paves the way for the most stringent test of quantum electrodynamics in strong magnetic fields and demonstrates the feasibility of laser spectroscopy on other exotic ions with low production yields.

Abstract Background Heterometallic gold metallacages are of great interest for the incorporation of several cations. Especially in nuclear medicine, those metallacages can serve as a platform for radionuclides relevant for imaging or therapy (e.g. 68Ga or 177Lu). Moreover, the radionuclide 198Au is an attractive beta emitter, for potential application in nuclear medicine. Here, we aim to synthesize a new set of gold metallacages and to study their ability to coordinate to 68Ga, 177Lu and 198Au. Results New heterometallic gold metallacages of composition [M{Au(Lmorph-κS)}3] (M = La3+, Tb3+, Lu3+ or Y3+) and [Ga{Au(Lmorph-κS)}2]NO3 have been synthesized from 2,6-dipicolinoylbis(N,N-morpholinylthiourea) (H2Lmorph) with [AuCl(THT)] and the target M3+ metal ions in yields ranging from 33 (Lu) to 62% (Tb). The characterization of the compounds bases on ESI–MS, 1H NMR, IR, EA and single-crystal X-ray diffraction techniques (all except the Ga derivative). Selected gold cages derived from H2Lmorph were compared to previously reported gold cages that were derived from 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2Ldiethyl). The tested metallacages show similar IC50 values close to that of auranofin in four different cancer cell lines (MCF-7, PC-3, U383, U343), e.g. 4.5 ± 0.7 µM for [Ga{Au(Ldiethyl)}2]NO3 on PC-3. The radiolabeling experiments thereof show high radiochemical purities with 68Ga and 198Au and low radiochemical purity with 177Lu. Conclusions The results indicate that these gold metallacages could serve as a novel platform for inclusion of different (radio)nuclides with potential theranostic applications in nuclear medicine.

Background Heterometallic gold metallacages are of great interest for the incorporation of several cations. Especially in nuclear medicine, those metallacages can serve as a platform for radionuclides relevant for imaging or therapy (e.g. 68 Ga or 177 Lu). Moreover, the radionuclide 198 Au is an attractive beta emitter, for potential application in nuclear medicine. Here, we aim to synthesize a new set of gold metallacages and to study their ability to coordinate to 68 Ga, 177 Lu and 198 Au. Results New heterometallic gold metallacages of composition [M{Au(L morph -κS)} 3 ] (M = La 3+ , Tb 3+ , Lu 3+ or Y 3+ ) and [Ga{Au(L morph -κS)} 2 ]NO 3 have been synthesized from 2,6-dipicolinoylbis( N,N -morpholinylthiourea) (H 2 L morph ) with [AuCl(THT)] and the target M 3+ metal ions in yields ranging from 33 (Lu) to 62% (Tb). The characterization of the compounds bases on ESI–MS, 1 H NMR, IR, EA and single-crystal X-ray diffraction techniques (all except the Ga derivative). Selected gold cages derived from H 2 L morph were compared to previously reported gold cages that were derived from 2,6-dipicolinoylbis( N,N -diethylthiourea) (H 2 L diethyl ). The tested metallacages show similar IC 50 values close to that of auranofin in four different cancer cell lines (MCF-7, PC-3, U383, U343), e.g. 4.5 ± 0.7 µM for [Ga{Au(L diethyl )} 2 ]NO 3 on PC-3. The radiolabeling experiments thereof show high radiochemical purities with 68 Ga and 198 Au and low radiochemical purity with 177 Lu. Conclusions The results indicate that these gold metallacages could serve as a novel platform for inclusion of different (radio)nuclides with potential theranostic applications in nuclear medicine.

This paper reports on the development of stable tumor-specific gold nanoparticles (AuNPs) activated by neutron irradiation as a therapeutic option for the treatment of cancer with high tumor angiogenesis. The AuNPs were designed with different mono- or dithiol-ligands and decorated with different amounts of Arg-Gly-Asp (RGD) peptides as a tumor-targeting vector for αvβ3 integrin, which is overexpressed in tissues with high tumor angiogenesis. The AuNPs were evaluated for avidity in vitro and showed favorable properties with respect to tumor cell accumulation. Furthermore, the therapeutic properties of the [198Au]AuNPs were evaluated in vitro on U87MG cells in terms of cell survival, suggesting that these [198Au]AuNPs are a useful basis for future therapeutic concepts.

Ir modification of FeNC catalysts improves the durability of the catalysts, but causes electronic changes that are disadvantageous for the activity.

The determination of astrophysically relevant neutron-induced cross sections is particularly difficult when the involved isotopes are radioactive or the cross sections are very small. Activation experiments at reactors offer the possibility to overcome these limitations with high neutron fluxes. The flux determination is typically based on the activation of two monitors with known cross sections to separate the different flux components. The usually applied cadmium difference method allows a distinction between the thermal and the epithermal part. By a combination of two linear functions representing both monitors the neutron flux components can be determined. However, if more than two monitors are used, the linear system of equations is overdetermined, which allows the identification of a probability distribution. In this proceeding, the feasibility and relevance of this method is demonstrated.

The research reactor TRIGA Mainz (FR MZ) is situated at the Johannes Gutenberg-University in Mainz, Germany. This TRIGA mark II reactor is one of the last three operating research reactors with a thermal power above 50 W in Germany. The FR MZ provides maximum thermal power of 100 kW in steady state operation mode and up to 250 MW pulse peak power at a pulse width of about 25 ms in pulsed operation mode. By now, it is under operation for 52 years and represents about 49000 operating hours and more than 23500 pulses in total.

The LIBELLE experiment performed at the experimental storage ring at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogen-like (Bi-209(82+)) and lithium-like (Bi-209(80+)) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. Besides the transition wavelengths the time-resolved detection of fluorescence photons following the excitation of the ions by a pulsed laser system also allows the extraction of lifetimes of the upper HFS levels and g-factors of the bound 1s and 2s electrons for both charge states. While the lifetime of the upper HFS state in Bi-209(82+) has already been measured in earlier experiments, an experimental value for lifetime of this state in Bi-209(80+) is reported for the first time in this work.

The TRIGA Mark II-reactor at the Johannes Gutenberg University Mainz (JGU) is one of three research reactors in Germany. The TRIGA Mainz became first critical on August 3rd, 1965. It can be operated in the steady state mode with a maximum power of 100 kW(th) and in the pulse mode with a peak power of 250 MWth and a pulse length of 30 ms. The TRIGA Mainz is equipped with a central thimble, a rotary specimen rack, three pneumatic transfer systems, four beam tubes, and a graphite thermal column. The TRIGA Mainz is intensively used both for basic and applied research in nuclear chemistry and nuclear physics. Two sources for ultra-cold neutrons (UCN) are operational at two beam ports. At a third beam port a Penning-Trap for highly precise mass measurements of exotic nuclides is installed. Education and training is another main field of activity. Here, various courses in nuclear and radiochemistry, reactor operation and reactor physics are held for scientists, advanced students, engineers, and technicians utilizing the TRIGA Mainz reactor.

Collinear Laser spectroscopy was applied to measure the hyperfine structure of 135 − 137Pr at ISOLDE/CERN. Combined with measurements of the stable isotope 141Pr at the TRIGA-SPEC setup in Mainz we were able to determine the magnetic moments of the neutron-deficient isotopes 135Pr, 136Pr and 137Pr for the first time.

We present results of laser spectroscopic high voltage measurements on the 5 ppm relative uncertainty level using a pump and probe scheme on Ca+ ions. With the two-stage laser interaction and with a reference measurement we can eliminate systematic effects like differences in contact potentials of electrode materials, thermo-electric voltages, and the unknown starting potential of the ions in the ion source. Our measurements are compatible with the 5 ppm precision limits of the high voltage dividers used for comparison and demonstrate an unprecedented increase in the precision of laser-based high voltage measurements by a factor of 20.

A recent measurement of the hyperfine splitting in the ground state of Li-like ^{208}Bi^{80+} has established a "hyperfine puzzle"-the experimental result exhibits a 7σ deviation from the theoretical prediction [J. Ullmann et al., Nat. Commun. 8, 15484 (2017)NCAOBW2041-172310.1038/ncomms15484; J. P. Karr, Nat. Phys. 13, 533 (2017)NPAHAX1745-247310.1038/nphys4159]. We provide evidence that the discrepancy is caused by an inaccurate value of the tabulated nuclear magnetic moment (μ_{I}) of ^{209}Bi. We perform relativistic density functional theory and relativistic coupled cluster calculations of the shielding constant that should be used to extract the value of μ_{I}(^{209}Bi) and combine it with nuclear magnetic resonance measurements of Bi(NO_{3})_{3} in nitric acid solutions and of the hexafluoridobismuthate(V) BiF_{6}^{-} ion in acetonitrile. The result clearly reveals that μ_{I}(^{209}Bi) is much smaller than the tabulated value used previously. Applying the new magnetic moment shifts the theoretical prediction into agreement with experiment and resolves the hyperfine puzzle.

After the events at the Fukushima-I nuclear power plant (NPP) in 2011 the Reaktorsicherheitskommission (RSK) has carried out an overall assessment of the German nuclear fleet with respect to extreme (beyond design base) events. The RSK is an expert group of operators, technical support organizations (TSO) and scientists that consults the German Federal Ministry of the Environment (BMUB) in questions concerning reactor safety. This paper deals only with the research reactors (RR) FRM II (Garching) and FR MZ (Mainz). The findings of the RSK, its recommendations and their status of implementation will be presented.

We present results of laser spectroscopic high voltage measurements on the 5 ppm relative uncertainty level using a pump and probe scheme on Ca + ions. With the two-stage laser interaction and with a reference measurement we can eliminate systematic effects like differences in contact potentials of electrode materials, thermo-electric voltages, and the unknown starting potential of the ions in the ion source. Our measurements are compatible with the 5 ppm precision limits of the high voltage dividers used for comparison and demonstrate an unprecedented increase in the accuracy of laser-based high voltage measurements by a factor of 20.

We have recently reported on the first direct measurement of the 2 s hyperfine transition in lithium-like bismuth (209Bi80+) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Combined with a new measurement of the 1 s hyperfine splitting (HFS) in hydrogen-like (209Bi82+) the so-called specific difference Δ ′ E = − 61.37 ( 36 ) meV could be determined and was found to be in good agreement with its prediction from strong-field bound-state quantum electrodynamics. Here we report on additional investigations performed to estimate systematic uncertainties of these results and on details of the experimental setup. We show that the dominating uncertainty arises from insufficient knowledge of the ion beam velocity which is determined by the electron-cooler voltage. Two routes to obtain a cooler-voltage calibration are discussed and it is shown that agreement can be reached either between the experimental Δ ′ E and the theoretical result, or between the two measurements of the HFS in hydrogen-like bismuth, but not both at the same time.

Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209 Bi 82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron–nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209 Bi 82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7- σ discrepancy compared with the theoretical prediction.

Hyperfine structure A and B factors of the atomic 5s5p 3P2 → 5s6s 3S1 transition are determined from collinear laser spectroscopy data of 107−123Cd and 111m−123m Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with s 1/2 and d 5/2 nuclear ground states and isomeric h 11/2 states is evaluated and a linear relationship is observed for all nuclear states except s 1/2. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic 5s5p 3P2 level is derived from multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the spectroscopic nuclear quadrupole moments. The results are consistent with those obtained in an ionic transition and based on a similar calculation.