Synthesis and preclinical evaluation of BOLD-100 radiolabeled with ruthenium-97 and ruthenium-103

BOLD-100 (formerly IT-139, KP1339), a well-established chemotherapeutic agent, is currently being investigated in clinical trials for the treatment of gastric, pancreatic, colorectal, and bile duct cancer. Despite numerous studies, the exact mode of action is still the subject of discussions. Radiolabeled BOLD-100 could be a powerful tool to clarify pharmacokinetic pathways of the compound and to predict therapy responses in patients using nuclear molecular imaging prior to the therapy. In this study, the radiosyntheses of carrier-added (c.a.) [97/103Ru]BOLD-100 were performed with the two ruthenium isotopes ruthenium-103 (103Ru; β-, γ) and ruthenium-97 (97Ru; EC, γ), of which in particular the latter isotope is suitable for imaging by single-photon emission computed tomography (SPECT). To identify the best tumor-to-background ratio for diagnostic imaging, biodistribution studies were performed with two different injected doses of c.a. [103Ru]BOLD-100 (3 and 30 mg kg-1) in Balb/c mice bearing CT26 allografts over a time period of 72 h. Additionally, ex vivo autoradiography of the tumors (24 h p.i.) was conducted. Our results indicate that the higher injected dose (30 mg kg-1) leads to more unspecific accumulation of the compound in non-targeted tissue, which is likely due to an overload of the albumin transport system. It was also shown that lower amounts of injected c.a. [103Ru]BOLD-100 resulted in a relatively higher tumor uptake and, therefore, a better tumor-to-background ratio, which are encouraging results for future imaging studies using c.a. [97Ru]BOLD-100.

Development of a Novel Passive Monitoring Technique to Showcase the 3D Distribution of Tritiated Water (HTO) Vapor in Indoor Air of a Nuclear Facility

Tritiated water (HTO), a ubiquitous byproduct of the nuclear industry, is a radioactive contaminant of major concern for environmental authorities. Although understanding spatiotemporal heterogeneity of airborne HTO vapor holds great importance for radiological safety as well as diagnosing a reactor's status, comprehensive HTO distribution dynamics inside nuclear facilities has not been studied routinely yet due to a lack of appropriate monitoring techniques. For current systems, it is difficult to simultaneously achieve high representativeness, sensitivity, and spatial resolution. Here, we developed a passive monitoring scheme, including a newly designed passive sampler and a tailored analytical protocol for the first comprehensive 3D distribution characterization of HTO inside a nuclear reactor facility. The technique enables linear sampling in any environment at a one-day resolution and simultaneous preparation of hundreds of samples within 1 day. Validation experiments confirmed the method's good metrological properties and sensitivity to the HTO's spatial dynamics. The air in TU Wien's reactor hall exhibits a range of 3H concentrations from 75-946 mBq m-3 in the entire 3D matrix. The HTO release rate estimated by the mass-balance model (3199 ± 306 Bq h-1) matches the theoretical calculation (2947 ± 254 Bq h-1), suggesting evaporation as the dominant HTO source in the hall. The proposed method provides reliable and quality-controlled 3D monitoring at low cost, which can be adopted not only for HTO and may also inspire monitoring schemes of other indoor pollutants.

Growth and characterization of thorium-doped calcium fluoride single crystals

We have grown [Formula: see text]Th:CaF[Formula: see text] and [Formula: see text]Th:CaF[Formula: see text] single crystals for investigations on the VUV laser-accessible first nuclear excited state of [Formula: see text]Th, with the aim of building a solid-state nuclear clock. To reach high doping concentrations despite the extreme scarcity (and radioactivity) of [Formula: see text]Th, we have scaled down the crystal volume by a factor 100 compared to established commercial or scientific growth processes. We use the vertical gradient freeze method on 3.2 mm diameter seed single crystals with a 2 mm drilled pocket, filled with a co-precipitated CaF[Formula: see text]:ThF[Formula: see text]:PbF[Formula: see text] powder in order to grow single crystals. Concentrations of [Formula: see text] cm[Formula: see text] have been realized with [Formula: see text]Th with good (> 10%) VUV transmission. However, the intrinsic radioactivity of [Formula: see text]Th drives radio-induced dissociation during growth and radiation damage after solidification. Both lead to a degradation of VUV transmission, currently limiting the [Formula: see text]Th concentration to [Formula: see text] cm[Formula: see text].

Neutron activation analysis in Mediterranean Archaeology: current applications and future perspectives

This paper, jointly written by participants of a workshop held in 2021, argues for an increased recognition and application of neutron activation analysis (NAA) in the archaeology of the ancient Mediterranean. Discussing the methodological strengths and challenges, it highlights the great potential NAA has for collecting proxy data from ceramics in order to develop progressive concepts of archaeological research within and beyond the Mediterranean Bronze and Iron Age, pointing out opportunities to revisit long-held assumptions of scholarship and to refine visual/macroscopic provenance determinations of pottery. To take full advantage of NAA's strengths toward a better understanding of the socioeconomic background of ceramics production, distribution, and consumption, the paper emphasises the need for both interdisciplinary collaboration and basic data publication requirements.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12520-023-01728-1.

Radiochemical effects of thermal neutron capture in Cr(tmhd)3: method development

The radiochemical effects of thermal neutron capture in tris(2,2,6,6-tetramethyl-3,5-heptandionato)chromium(III) (Cr(tmhd)3) were investigated. A method was devised to quantify the amount of the induced 51Cr activity recoverable in the original chemical form and to confirm that it is indeed Cr(tmhd)3. The method is based on a combination of chemical separation (column chromatography and recrystallization) and analytical (radio-TLC, HPLC, and gamma spectrometry) techniques. Cr(tmhd)3 samples were irradiated and purified in two steps after irradiation. We found that two of the (three) purification pathways yielded good agreement among final 51Cr activity concentrations. The corresponding samples appeared to be of exceptional radiochemical purity.

Measurement of the ^{229}Th Isomer Energy with a Magnetic Microcalorimeter

We present a measurement of the low-energy (0-60 keV) γ-ray spectrum produced in the α decay of ^{233}U using a dedicated cryogenic magnetic microcalorimeter. The energy resolution of ∼10  eV, together with exceptional gain linearity, allows us to determine the energy of the low-lying isomeric state in ^{229}Th using four complementary evaluation schemes. The most precise scheme determines the ^{229}Th isomer energy to be 8.10(17) eV, corresponding to 153.1(32) nm, superseding in precision previous values based on γ spectroscopy, and agreeing with a recent measurement based on internal conversion electrons. We also measure branching ratios of the relevant excited states to be b_{29}=9.3(6)% and b_{42}<0.7%.

Total reflection X-ray fluorescence analysis of elemental composition of herbal infusions and teas

BACKGROUND

The elemental composition of herbal infusions and teas has not been sufficiently investigated. It could potentially be used for defining fingerprints for individual herbal / tea infusions, differentiation of botanical families, detecting the influence of packaging, and other purposes. The objective of this study was to determine the elemental composition, including the trace element content, of various herbal infusions and teas by means of total reflection X-ray fluorescence analysis (TXRF), with a chemometrics approach using principal component analysis (PCA).

RESULTS

This study determined the elemental composition of various herbal infusions and teas, including trace elements, using total reflection X-ray fluorescence (TXRF). The methodology for the sample preparation was established, including the multiple-steepings procedure for the two tea samples (Oolong and Pu-erh). Data from 29 samples were collected. We hypothesized that the elemental content of infusions could reflect certain features, such as the influence of processing and the type of tea.

CONCLUSION

A chemometric approach (PCA) was applied, and differences between teas and herbal infusions were found. This was further corroborated by explicit differentiation of one botanical family, Theaceae. The influence of packaging (tea bags) on herbal material was identified. The three types of tea (Camellia sinensis) appeared to be separated with PCA, and elemental concentrations in Pu-erh changed with multiple steepings.

Chemical and radioanalytical investigations of 106Ru-containing air filters from Vienna in fall 2017: searching for stable element anomalies

Related to the recent nuclear release of radioactive ruthenium isotopes in fall 2017, we analyzed air filters from Vienna for irregularities in the (stable) elemental composition of particulate matter from this period. Methods were SEM/EDXS and INAA. For comparison, a reference filter from 2007 and blank filters were used. The chemical fingerprint encompassed 28 elements. The results show no indication for a considerable change in the elemental composition of the suspended matter. For example, no anomalies in the abundance of platinum group elements were found. The results suggest that the release of ¹⁰⁶Ru had not been accompanied by a release of detectable amounts of (activatable) stable elements.

Adsorption characteristics of a clinoptilolite-rich zeolite compound for Sr and Cs

The Sr and Cs adsorption capacities of LithoFill™, LithoGran™ and a competing clinoptilolite containing zeolite product were investigated by radioanalytical methods (⁸⁵Sr and ¹³⁴Cs gamma spectroscopy). The dependence of adsorption and adsorption rate on physical factors including temperature, available ions and time were assessed. In addition, the reversibility of adsorption under high ionic strength conditions was also examined. In general, cesium is more strongly adsorbed than strontium, adsorption yields are generally independent of temperature (from room temperature to 65 °C) and adsorption is relatively rapid (identical results for 2 or 5 day adsorption times). As expected, increasing the concentration of other ions in solution tends to reduce adsorption of cesium and strontium. In general, Cs adsorption ranges between 54.5 and 45.2 mg/g for LitoFill and LitoGran samples and between 36.9 and 24.4 mg/g for the competing product. For Sr adsorption, ranges are 30-21 mg/g and 7.3-6.7 mg/g respectively, leading to the conclusion that the higher content of clinoptilolite in the LitoFill/LitoGran samples results in better adsorption characteristics.

A workflow for neutron activation analysis of archaeological ceramics at the Atominstitut in Vienna, Austria

The main focus for neutron activation analysis (NAA) at the Atominstitut in Vienna has moved to the analysis of archaeological ceramics. The workflow for NAA has been adapted for this material and the elemental spectrum quantified has been expanded for compatibility with international databases. Statistical methods for the grouping of the archaeometric data have been implemented, following the methods applied by Mommsen et al. in Bonn (Archaeometry 30(1):47–57, 1988). Limits of detection specific for ceramics have been calculated and are at the ng/g level. High reproducibility as necessary for archaeometric analysis can be shown by comparative measurements of an internal quality control sample.

Long-term environmental radioactive contamination of Europe due to the Chernobyl accident - Results of the Joint Danube Survey 2013

In the course of the Joint Danube Survey 3 (JDS3), coordinated by the International Commission for the Protection of the Danube River (ICPDR), laboratory ships travelled 2375km down the Danube River engaging in sampling, processing and on-board analyses during the summer of 2013. The results of the radiometric analysis of ⁹⁰Sr, ¹³⁷Cs and natural radionuclides in recent riverbed sediment are presented. The activity concentrations of ⁹⁰Sr and ¹³⁷Cs in Danube sediments have been found below 100Bq/kg.

Settling the half-life of 60Fe: fundamental for a versatile astrophysical chronometer

In order to resolve a recent discrepancy in the half-life of 60Fe, we performed an independent measurement with a new method that determines the 60Fe content of a material relative to 55Fe (t1/2=2.744  yr) with accelerator mass spectrometry. Our result of (2.50±0.12)×10(6)  yr clearly favors the recently reported value (2.62±0.04)×10(6)  yr, and rules out the older result of (1.49±0.27)×10(6)  yr. The present weighted mean half-life value of (2.60±0.05)×10(6)  yr substantially improves the reliability as an important chronometer for astrophysical applications in the million-year time range. This includes its use as a sensitive probe for studying recent chemical evolution of our Galaxy, the formation of the early Solar System, nucleosynthesis processes in massive stars, and as an indicator of a recent nearby supernova.

Investigation of the isotopic ratio 129I/I in petrified wood

In fossil specimens, measurements of the natural isotopic ratio (129)I/I may provide a method to estimate the age of sample. The motivation for measuring the isotopic composition ((129)I/I) of petrified wood samples collected from Austria was to check this feasibility. Alkaline fusion together with anion exchange was used to extract iodine from the sample. Typical sample size for this study was 10-90 g. An atomic ratio as low as 10(-14) was determined using accelerator mass spectrometry (AMS). Uranium concentrations measured by instrumental neutron activation analysis (INAA) and α-spectrometry were found to be less than 3 mg kg(-1), therefore the contribution from fissiogenic (129)I was small and an estimation of ages was based on the decrease of the initial ratio (due to decay of the cosmogenic (129)I in a closed system) after subtraction of the fissiogenic (129)I. The value of the prenuclear ratio is crucial for the use of the (129)I system for dating purposes in the terrestrial environment. From the preanthropogenic (initial) ratio of 1.5 × 10(-12) of the hydrosphere and the results of the present study for the samples from Altenburg (1.05 × 10(-12)) and Fuerwald (6.16 × 10(-13)), respective ages of 8 ± 2.2 and 20.2 ± 2.2 million years were derived. Since samples were collected from a stratum deposited in the Upper Oligocene/Ergerien period (~25-30 million years ago), it can be concluded that these isotopic ratios do not show ages but an elapsed time since fossil wood was isolated from mineral rich water. Paleontological investigation shows that samples from Altenburg had mixed characteristics of old and modern Tertiary plants, thus an origin from a younger stratum re-sedimented with Oligocene cannot be excluded. However, the sample from Drasenhofen reflects that the (129)I/I system might not always be suitable for the dating of petrified wood sample due to fixation of anthropogenic (129)I into surface fractures.

Artificial radioactivity in environmental media (air, rainwater, soil, vegetation) in Austria after the Fukushima nuclear accident

Several environmental media in Austria were monitored for artificial radionuclides released during the Fukushima nuclear accident. Air (up to 1.2 mBq/m(3) particulate (131)I) and rainwater (up to 5.2 Bq/L (131)I) proved to be the media best suited for the environmental monitoring, allowing also a temporal resolution of the activity levels. Significant regional differences in the wet deposition of (131)I with rain could be observed within the city of Vienna during the arrival of the contaminated air masses. Forward-trajectory analysis supported the hypothesis that the contaminated air masses coming from the northwest changed direction to northeast over Northern Austria, leading to a strong activity concentration gradient over Vienna. In the course of the environmental monitoring of the Fukushima releases, this phenomenon-significant differences of (131)I activity concentrations in rainwater on a narrow local scale (8.1 km)-appears to be unique. Vegetation (grass) was contaminated with (131)I and/or (137)Cs at a low level. Soil (up to 22 Bq/kg (137)Cs) was only affected by previous releases (nuclear weapon tests, Chernobyl). Here, also significant local differences can be observed due to different deposition rates during the Chernobyl accident. The effective ecological half-lives of (137)Cs in soil were calculated for four locations in Austria. They range from 7 to 30 years. No Austrian sample investigated herein exceeded the detection limit for (134)Cs; hence, the Fukushima nuclear accident did not contribute significantly to the total radiocesium inventory in Austrian environmental media. The levels of detected radioactivity were of no concern for public health.

Nuclear forensics of a colored gemstone: evidence of proton bombardment of a blue topaz

A blue topaz was investigated radiologically for forensic purposes. It clearly exhibited detectable activities of (22)Na (0.28 ± 0.01 Bq). The occurrence of this artificial radionuclide evidences fraudulent irradiation of the gemstone with protons to give it its blue color. It can be assumed that also (7)Be must have been produced in the course of proton bombardment, yielding even greater activities than (22)Na. Since no traces of short-lived (7)Be could be detected, the topaz must have been irradiated at least 300 days prior to measurement.

Peer review versus editorial review and their role in innovative science

Peer review is a widely accepted instrument for raising the quality of science. Peer review limits the enormous unstructured influx of information and the sheer amount of dubious data, which in its absence would plunge science into chaos. In particular, peer review offers the benefit of eliminating papers that suffer from poor craftsmanship or methodological shortcomings, especially in the experimental sciences. However, we believe that peer review is not always appropriate for the evaluation of controversial hypothetical science. We argue that the process of peer review can be prone to bias towards ideas that affirm the prior convictions of reviewers and against innovation and radical new ideas. Innovative hypotheses are thus highly vulnerable to being "filtered out" or made to accord with conventional wisdom by the peer review process. Consequently, having introduced peer review, the Elsevier journal Medical Hypotheses may be unable to continue its tradition as a radical journal allowing discussion of improbable or unconventional ideas. Hence we conclude by asking the publisher to consider re-introducing the system of editorial review to Medical Hypotheses.

On the geochemistry of the Kyra eruption sequence of Nisyros volcano on Nisyros and Tilos, Greece

The Kyra sequence is a volcanic eruption sequence originating from the eastern flank of Nisyros volcano, Greece. Its eruptions products can be found not only on Nisyros itself but also on the nearby non-volcanic island of Tilos. In an extensive sampling campaign, outcrops of the Kyra eruption products on Nisyros were sampled and corresponding samples on Tilos were taken. The clear stratigraphical relationship between the different units within in the individual outcrops, combined with the chemical information gained by the application of instrumental neutron activation analysis (INAA) to the samples, made a detailed chemo-stratigraphy of the complete eruption sequence possible. It can be shown that the sequence is separated into eight distinguishable eruptions. Furthermore, no eruption products of the caldera-forming eruptions from Nisyros (Lower- and Upper Caldera Pumice) or from Santorin were found on Tilos.

Provenancing of archeological pumice finds from North Sinai

Seven pumice samples from excavations in North Sinai have been investigated with respect to their geochemical composition. This type of volcanic rock has been used as an abrasive and thus has been an object of trade since antiquity. With the help of Instrumental Neutron Activation Analysis, six of these Bronze Age samples could be correlated to their volcanic sources on the islands of Santorini, Nisyros and Giali (Greece) using the typical element concentrations ("chemical fingerprint"). The source of one pumice sample remains unidentified excluding, however, the Santorini eruption as a possible source. The concluding section of this article discusses the possible contribution, however indirect, of the pumice from Sinai and elsewhere in the Eastern Mediterranean to the controversial issue of the accurate date of the "Minoan" eruption of Santorini.

Expanding the menu for carnivorous plants: uptake of potassium, iron and manganese by carnivorous pitcher plants

Carnivorous plants use animals as fertiliser substitutes which allow them to survive on nutrient deficient soils. Most research concentrated on the uptake of the prey's nitrogen and phosphorus; only little is known on the utilisation of other elements. We studied the uptake of three essential nutrients, potassium, iron and manganese, in three species of carnivorous pitcher plants (Cephalotus follicularis LaBilladiere, Sarracenia purpureaL., Heliamphora nutans Bentham). Using relatively short-lived and gamma-emitting radiotracers, we significantly improved the sensitivity compared to conventional protocols and gained the following results. We demonstrated the uptake of trace elements like iron and manganese. In addition, we found direct evidence for the uptake of potassium into the pitcher tissue. Potassium and manganese were absorbed to virtually 100% if offered in physiological concentrations or below in Cephalotus. Analysis of pitcher fluid collected in the natural habitat showed that uptake was performed here as efficiently as in the laboratory. The absorption of nutrients is an active process depending on living glandular cells in the pitcher epidermis and can be inhibited by azide. Unphysiologically high amounts of nutrients were taken up for a short time, but after a few hours the absorbing cells were damaged, and uptake stopped. Absorption rates of pitcher leaves from plants under controlled conditions varied highly, indicating that each trap is functionally independent. The comparison of minerals in typical prey with the plants' tissues showed that a complete coverage of the plants' needs by prey capture is improbable.

“Chemical fingerprints” of pumice from Cappadocia (Turkey) and Kos (Greece) for archaeological applications

Pumice has been used as a serviceable abrasive or religious artefact since antiquity and has therefore been an object of trade. It can be found in excavations of ancient workshops all over the Mediterranean. Pumice lumps from the major pumice-bearing rhyolitic tephra units in Cappadocia-the Central Anatolian Volcanic Province, Turkey (in particular the ignimbrites Kavak, Cemilköy, Tahar, Gördeles, and the volcanic complexes of Acigöl and Hasan Daği), were sampled and analyzed for major and trace element concentrations using instrumental neutron activation analysis (INAA). Elements determined were Na, K, Sc, Cr, Fe, Co, Zn, As, Rb, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th, and U. Since the distribution of those elements is characteristic of the products of a certain eruption, this "chemical fingerprint" can be used to establish the origin of an unknown pumice sample by comparison with samples of known origin. In the course of this study, it could be shown that one pumice finding from the excavation in Miletos (Turkey) probably originates from the Hasan Daği volcanic complex in Cappadocia. Since it is known that the population in Miletos focused their trade connections on the Mediterranean, this result is somewhat surprising. Two other samples from Miletos show a very high similarity to the chemical fingerprint of pumice from the Kos Plateau Tuff (KPT; Greece): In one case, the identification is doubtless, in the other case identification as KPT seems quite probable.

Beyond low-level activity: on a "non-radioactive" gas mantle

Gas mantles for camping gas lanterns sometimes contain thorium compounds. During the last years, the use of thorium-free gas mantles has become more and more popular due to the avoidance of a radioactive heavy metal. We investigated a gas mantle type that is declared to be "non-radioactive" and that can be bought in Austria at the moment. Methods used were Instrumental Neutron Activation Analysis (INAA), gamma-spectroscopy, and Liquid Scintillation Counting (LSC). We found massive thorium contents of up to 259 mg per gas mantle. Leaching experiments showed that only 0.4% of the Th but approximately 90% of the decay products of (232)Th can be leached under conditions simulating sucking and chewing with human saliva. In this paper, the investigation of these gas mantles including the consideration of the environmental hazard caused by disposed mantles and the health hazard for unsuspecting consumers is presented and legal consequences are discussed for this fraud.

Trace elements in rock salt and their bioavailability estimated from solubility in acid

In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded.