The study analyses in situ CO2 mole fraction, 14CO2, and fossil based excess CO2 mole fraction (Cfoss) data at Hegyhátsál (HUN) rural monitoring station (Central Europe) supplemented by passive monitoring of 14C content of tree-rings. Through the observed period (2014–2020) we focused on revealing trends in atmospheric CO2 and 14C levels, particularly during the year of the first COVID lockdown, in comparison to the preceding five years. In addition, monthly integrated samples of atmospheric CO2 and tree-rings from the six years were subjected to 14C analysis. The passive tree-ring measurements focuses on two major urban areas (Budapest and Debrecen) in Hungary, along with the rural monitoring site. Results show a steady increase in CO2 levels at HUN between 2014 and 2020. The calculated fossil based excess CO2 concentrations for the initial year of COVID are in good agreement with the previous five-year averages both at 115 m and 10 m elevations. These results also show seasonal variations of CO2 mole fractions, peaking in winter and decreasing in summer. Tree-ring results from Debrecen show a good alignment with the results of the atmospheric monitoring station, and it does not show a significant fossil contribution in the urban background area during the vegetation periods. Tree-ring results from Budapest show a stronger fossil contribution compared to the Debrecen ones. Our atmospheric CO2 results do not show a large decrease in fossil CO2 atmospheric contribution during the first lockdown. We found that the use of this passive CO2 monitoring technique can provide a valuable tool for investigating such differences.

Biobased content analysis is a well-established, analytically independent, standardized method to determine the biobased content of fuels and plastics, based on differences of the specific radiocarbon (14C) activity of fossil and recent biogenic compounds. This biogenic content analysis can be useful for the producers as a quality assurance tool, for the customers as feedback about the truly biobased products and for the control organizations as an independent analytical tool to prove the biological origin. More than 100 commercially available foods, cosmetics, and drug samples have been used for biobased carbon content analysis by accelerator mass spectrometry (AMS) 14C measurement to demonstrate the potential of this technique. Our results show that this measurement technique is a unique tool for the determination of biocontent in foodstuff and medical products. Most of the tested materials were nearly or completely biobased (≥ 98 pMC), and no completely fossil-based final product was detected. The lowest biogenic compound was measured in a vanilla aroma flavor. In 45 of the 102 samples selected a wide range (2–98%) presented fossil-based carbon content. The method can be applied for monitoring raw materials and final products for biobased content in the industry and consumer protection as well.

The method of determining the biobased carbon content in liquid fuel samples is standardized, but different laboratories use different protocols during sample preparation and perform the measurements using different machines. The accelerator mass spectrometry (AMS) laboratories use different combustion, preparation, and graphitization methods for the graphite production for the spectrometric measurements. As a result, the intercomparison between the laboratories is inevitable to prove precision and accuracy and to demonstrate that the results are comparable. In this study, we present the results of an intercomparison campaign involving three 14C accelerator mass spectrometry laboratories. Five samples were used in the measurement campaign, including two biocomponents (fatty acid methyl ester, hydrotreated vegetable oil), one fossil component (fossil diesel), and two blends (mixtures of fossil and biocomponent with 90–10% mixing ratio) in the laboratories of CEDAD (Italy), ETH (Switzerland), and INTERACT (Hungary). The results presented by the laboratories are comparable, and all three laboratories could determine the biobased carbon content of the samples within 1% relative uncertainty, which is acceptable in the scientific, economic, and industrial fields for biocomponent determination.

A signal of rapid changes in 14C production is logged in annual series of 14C derived from tree rings, which can be associated with diverse effects of cosmic-ray fluxes, including solar burst and supernova events. These 14C signatures may vary in time and space. The intensity and structure of the 14C signal is multifaced, which complicates understanding of the forcing and attribution of the underlying astrophysical events. It was suggested that Δ14C in 1052/53 CE and 1054/55 CE signatures at a 4‰–6‰ range over two years could be caused by the Crab Nebula supernova (SN1054) or/and solar perturbation. The temporal incoherence of the signals in published 14C series is investigated with dynamic time warping (DTW), novel approach for matching time-behavioral patterns in multiple 14C datasets. DTW analysis of four 14C signatures from tree rings of California, Finland and England suggests that 14C spikes between 1052 CE and 1055 CE can be caused by a single event. The flickering fingerprint may result from cross-dating inconformity. Cross-checking of tree-ring records from distant locations is impossible sometimes due to large difference in environmental conditions limiting tree growth. The methodology helps to align the signals and can be applied to other 14C datasets.

The most widely used dating techniques in quaternary research are the radiocarbon (14C) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for 14C dating. In these cases, 14C dating of bulk sediment may be used as a last resort. The major aim of the present study was to determine the reliability and limitations of the different fractions of the soil organic carbon (SOC) 14C ages in the Nyírség blown-sand study area, in Hungary. Therefore, the low- and high-temperature combustions of SOC (LT-SOC and HT-SOC) 14C age of fossil soils were compared with the charcoal ages from the same fossil soil layer, and their (LT-SOC, HT-SOC, and charcoal) age reliability was verified independently by applying OSL to the quartz fraction of the sediment samples. The 14C data show variable agreement with OSL ages. Charcoal fragments were collected from some of the best material for 14C dating and their ages are in agreement with the LT and HT-SOC 14C ages and OSL data. The 14C age LT-SOC gives a reliable, credible ages, which were confirmed by independent OSL measurements. If buried soils do not contain any other macroscopic remnants for 14C dating, the LT-SOC 14C ages can be used, in the case of the Nyírség study area. The LT-SOC, which is the younger fraction of the soil organic carbon, may be considered to represent the burial time of the fossil soil layer. The HT-SOC 14C ages are sometimes unrealistically older than expected and cannot be considered to be reliable.

A laboratory intercomparison project was carried out on 20 annually resolved late-wood samples from the Danish oak record. The project included the following three laboratories: (1) the University of Arizona AMS Laboratory, University of Arizona, USA (AA); (2) HEKAL AMS Laboratory, MTA Atomki, Hungary (DeA); and (3) Aarhus AMS Centre (AARAMS), Aarhus University, Denmark (AAR). The large majority of individual data points (96%) lie within ±2σ of the weighted mean. Further assessment of the accuracy associated with the individual laboratories showed good agreement, indicating that consistent and reliable 14C measurements well in agreement with each other are produced at the three laboratories. However, the quoted analytical uncertainties appear to be underestimated when compared to the observed variance of differences from the geometric mean of the samples. This study provides a general quality check of the single-year tree-ring 14C measurements that are included in the new calibration curve.

A coupled accelerator mass spectrometer–gas interface system has been successfully operating at the Hertelendi Laboratory of Environmental Studies, Debrecen, Hungary, since 2013. Over the last 6 years more than 500 gas targets were measured below 100 µg carbon content for carbon isotopic composition. The system was tested with blanks, OxII, IAEA-C1, IAEA-C2, and IAEA-C7 standards. The performance of our instrumentation shows good agreement with other published gas-interface system data and also shows a quite good agreement with the nominal value of international standard samples. There is a measurable but quite small memory effect after modern samples, but this does not significantly affect the final results. Typical ion currents at the low energy side were between 10–15 µA with a 5% CO2 in He mixing ratio. The relative errors average ±6% for samples greater than or equal to 10 µgC sample with mean count rates of 300 counts per microgram C for OxII. The blank is comparable with other systems, which is 0.0050 ± 0.0018 F14C or 34,000–47,000 yr BP, which allows for the routine measurement of both of small environmental and archeological samples.

Here it is demonstrated how some anionic food additives commonly used in our diet, such as tartrazine (TZ), bind to DHVAR4, an antimicrobial peptide (AMP) derived from oral host defense peptides, resulting in significantly fostered toxic activity against both Gram-positive and Gram-negative bacteria, but not against mammalian cells. Biophysical studies on the DHVAR4–TZ interaction indicate that initially large, positively charged aggregates are formed, but in the presence of lipid bilayers, they rather associate with the membrane surface. In contrast to synergistic effects observed for mixed antibacterial compounds, this is a principally different mechanism, where TZ directly acts on the membrane-associated AMP promoting its biologically active helical conformation. Model vesicle studies show that compared to dye-free DHVAR4, peptide–TZ complexes are more prone to form H-bonds with the phosphate ester moiety of the bilayer head-group region resulting in more controlled bilayer fusion mechanism and concerted severe cell damage. AMPs are considered as promising compounds to combat formidable antibiotic-resistant bacterial infections; however, we know very little on their in vivo actions, especially on how they interact with other chemical agents. The current example illustrates how food dyes can modulate AMP activity, which is hoped to inspire improved therapies against microbial infections in the alimentary tract. Results also imply that the structure and function of natural AMPs could be manipulated by small compounds, which may also offer a new strategic concept for the future design of peptide-based antimicrobials.

Selective laser sintering methods are workhorses for additively manufacturing polymer-based components. The ease of rapid prototyping also means it is easy to produce illicit components. It is necessary to have a data-calibrated in-situ physical model of the build process in order to predict expected and defective microstructure characteristics that inform component provenance. Toward this end, sintering models are calibrated and characteristics such as component defects are explored. This is accomplished by assimilating multiple data streams, imaging analysis, and computational model predictions in an adaptive Bayesian parameter estimation algorithm. From these data sources, along with a phase-field model, bulk porosity distributions are inferred. Model parameters are constrained to physically-relevant search directions by sensitivity analysis, and then matched to predictions using adaptive sampling. Using this feedback loop, data-constrained estimates of sintering model parameters along with uncertainty bounds are obtained.

We present the current status of a scalable computing framework to address the need of the multidisciplinary effort to study chemical dynamics. Specifically, we are enabling scientists to process and store experimental data, run large-scale computationally expensive high-fidelity physical simulations, and analyze these results using state-of-the-art data analytics, machine learning, and uncertainty quantification methods using heterogeneous computing resources. We present the results of this framework on a single metadata-driven workflow to accelerate an additive manufacturing use-case.

The increase of fossil-fuel-derived CO2 in the atmosphere has led to the dilution of the atmospheric radiocarbon concentration, but due to the costly instrumentation, the continuous atmospheric 14C/12C data is incomplete in developing countries, such as in Indonesia. These data give useful information about the level of local and regional fossil emissions. In this study, 14C AMS measurements of local vegetation and woody plant species samples have been used to estimate the rate of fossil-fuel-derived carbon in the plants, which fix the CO2 from the atmosphere by photosynthesis. Evergreen leaf samples were collected in September 2018 on the island of Bali in different, diverse districts in local and urban areas. The samples from the densely populated areas show observable fossil fuel emissions and show that the Δ14C level is close to zero ‰, similar to the natural level.

Deciduous tree leaf and grass samples were collected in Debrecen, the second largest city in Hungary. The aim of the study was to determine the rate of fossil fuel-derived carbon in urban vegetation. At the locations sampled, C3 and C4 plants close to roads were collected in September 2017. In total, 82 tree and grass leaf samples were gathered at 36 different sampling points all over the city of Debrecen. The radiocarbon (14C) results of the samples were compared to the local urban background atmospheric 14CO2 data to determine the percentage of the fossil fuel-derived carbon in the plants. Based on our results, the average fossil carbon content in the tree and grass leaf samples were 0.9 ± 1.2% and 2.5 ± 2.5%, respectively. The highest fossil carbon content was 9.6 ± 0.6% in a grass and 4.7 ± 0.7% in a tree leaf sample. It appears that the negative fossil carbon content results obtained at urban sampling areas reflect modern carbon emission, where radiocarbon content is higher than the corresponding local background, presumably due burning of recent wood containing bomb 14C in the suburbs as well as other possible sources such as litter decomposition or soil CO2 emission.

Radiocarbon (14C) analysis was performed on Japanese cedar (Cryptomeria japonica) tree rings from Koriyama, Fukushima prefecture. Our primary aim was to detect any 14C release from the Fukushima Dai-ichi nuclear power plant accident on 11 March 2011. We also completed and assessed the 14C level in Japanese tree rings for the period of 1990–2014 because of the lack of environmental 14C results in the Japanese island that time. For this reason, we used a trajectory model to investigate the air mass forward and backward trajectories at the area of the power plant and sampling site. The modeling data show that the air masses mainly moved to the Pacific Ocean, both during March 2011 and during the growing season (March–September). During the period 1990–2014 there was no significant 14C excess in any of the samples, but there was a detectable Suess effect in almost every tree ring sample. The average fossil contribution was 0.83 ± 0.01% and the calculated anthropogenic component ratio, the 14C excess varied between +0.5 and –1.6%. The Δ14C value decreased from 150.0‰ to 9.5‰ from 1990–2014, which follows the decline of the 14C bomb peak, in addition to any detectable Suess effect.

The biocomponent ratio in liquid fuels as well as the usage of renewable resources for fuel consumption in the transport sector needs to be increased as a result of EU directive 2003/30/EC. Based on radiocarbon (14C) measurements, it should be relatively simple and fast to measure the weight percentage of the fossil and biological sources by accelerator mass spectrometry (AMS) as recommended in the ASTM D 6866-12 and EN 16640 standards. In this study, a relatively easy and fast sample preparation and measurement method based on AMS measurements was developed at the Hertelendi Laboratory of Environmental Studies (HEKAL) using reference samples from the Hungarian MOL Nyrt. oil company. Considering the recent EU regulation for mixing rates of liquid fuels in the transport sector (0.7–2% biofuel content) and the projected higher rates (2–10% biofuel content), the method is applicable to determine fatty acid methyl ester (FAME) and/or hydrotreated vegetable oil (HVO) derived proportions of fuel blends with a 1σ uncertainty better than±0.3% m/m.

Two radiocarbon (14C) excursions are caused by an increase of incoming cosmic rays on a short time scale found in the Late Holocene (AD 774–775 and AD 993–994), which are widely explained as due to extreme solar proton events (SPE). In addition, a larger event has also been reported at 5480 BC (Miyake et al. 2017a), which is attributed to a special mode of a grand solar minimum, as well as another at 660 BC (Park et al. 2017). Clearly, other events must exist, but could have different causes. In order to detect more such possible events, we have identified periods when the 14C increase rate is rapid and large in the international radiocarbon calibration (IntCal) data (Reimer et al. 2013). In this paper, we follow on from previous studies and identify a possible excursion starting at 814–813 BC, which may be connected to the beginning of a grand solar minimum associated with the beginning of the Hallstatt period, which is characterized by relatively constant 14C ages in the period from 800–400 BC. We compare results of annual 14C measurements from tree rings of sequoia (California) and cedar (Japan), and compare these results to other identified excursions, as well as geomagnetic data. We note that the structure of the increase from 813 BC is similar to the increase at 5480 BC, suggesting a related origin. We also assess whether there are different kinds of events that may be observed and may be consistent with different types of solar phenomena, or other explanations.