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The aim of this study was the development and analytically validation of a radioimmunoassay system for the measurement of the serum ferritin concentration as one of the laboratory biomarkers for infection by Covid-19. The main components of the system were prepared in our laboratories. The first component ferritin was extracted and purified from human spleen with high purity. The second component was the 125I-labelled ferritin tracer, prepared using Chloramine-T method. Furthermore anti-ferritin antibodies and ferritin standards were provided. The developed system is sensitive, precise, reproducible and.can be translated into a kit formulation suitable for measuring serum ferritin for the detection of Covid-19 in patients at low costs and high efficiency.

Background The molecular chaperone, Hsp90, is a key player in the protein quality control system that maintains homeostasis under cellular stress conditions. It is a homodimer with ATP-dependent activity, and is a prominent member of the chaperone machinery that stabilizes, matures and (re)folds an extensive list of client proteins. Hsp90 occurs as four isoforms, cytosolic Hsp90α and Hsp90β, mitochondrial TRAP1 and Grp94 present in the endoplasmic reticulum. An aberrant role of Hsp90 has been attributed to several cancers and neurodegenerative disorders. Consequently, Hsp90 has emerged as an attractive therapeutic target. However, pan-Hsp90 inhibition often leads to detrimental dose-limiting toxicities. Novel strategies for Hsp90-targeted therapy intend to avoid this by using isoform-specific Hsp90 inhibition. In this respect, the radiosynthesis of carbon-11 labeled SNX-ab was developed and [11C]SNX-ab was evaluated as a Hsp90α,β isoform-selective PET probe, which could potentially allow to quantify in vivo Hsp90α,β expression. Results [11C]SNX-ab was synthesized with excellent radiochemical yields of 45% and high radiochemical purity (> 98%). In vitro autoradiography studies on tissue slices of healthy mouse brain, mouse B16.F10 melanoma and U87 glioblastoma using homologous (SNX-ab, SNX-0723) and heterologous (Onalespib and PU-H71) Hsp90 inhibitors demonstrated only limited reduction of tracer binding, indicating that the binding of [11C]SNX-ab was not fully Hsp90-specific. Similarly, [11C]SNX-ab binding to U87 cells was not efficiently inhibited by Hsp90 inhibitors. Ex vivo biodistribution studies in healthy mice revealed limited brain exposure of [11C]SNX-ab and predominantly hepatobiliary clearance, which was confirmed by in vivo full-body dynamic µPET studies. Conclusion Our results suggest that [11C]SNX-ab is not an ideal probe for in vivo visualization and quantification of Hsp90α/β expression levels in tumour and brain. Future research in the development of next-generation Hsp90 isoform-selective PET tracers is warranted to dissect the role played by each isoform towards disease pathology and support the development of subtype-specific Hsp90 therapeutics.

Purpose This study tests the feasibility of using a submersible spectrophotometer as a novel method to trace and apportion suspended sediment sources in situ and at high temporal frequency. Methods Laboratory experiments were designed to identify how absorbance at different wavelengths can be used to un-mix artificial mixtures of soil samples (i.e. sediment sources). The experiment consists of a tank containing 40 L of water, to which the soil samples and soil mixtures of known proportions were added in suspension. Absorbance measurements made using the submersible spectrophotometer were used to elucidate: (i) the effects of concentrations on absorbance, (ii) the relationship between absorbance and particle size and (iii) the linear additivity of absorbance as a prerequisite for un-mixing. Results The observed relationships between soil sample concentrations and absorbance in the ultraviolet visible (UV–VIS) wavelength range (200–730 nm) indicated that differences in absorbance patterns are caused by soil-specific properties and particle size. Absorbance was found to be linearly additive and could be used to predict the known soil sample proportions in mixtures using the MixSIAR Bayesian tracer mixing model. Model results indicate that dominant contributions to mixtures containing two and three soil samples could be predicted well, whilst accuracy for four-soil sample mixtures was lower (with respective mean absolute errors of 15.4%, 12.9% and 17.0%). Conclusion The results demonstrate the potential for using in situ submersible spectrophotometer sensors to trace suspended sediment sources at high temporal frequency.

Numerical simulation has shown that replacing a part of methane by carbon monoxide in a rich mixture while maintaining the equivalence ratio leads to a decrease in the superadiabatic temperature effect due to the competition of chemical reactions. This is explained by a decrease in the H content in the combustible mixture and a decrease in the superequilibrium concentration of water in combustion products. Using numerical tracer simulation and a comparative analysis of the rates of consumption of CH4 and CO, it has been found that the consumption of both fuels in the CH4/CO/air flame is a competitive reaction path and CO monoxide does not act as an inert component in the low-temperature region of the front (contrary to the statements of a number of authors). Furthermore, the rate of consumption of CH4 is much higher than that of CO due to the larger number of consumption reactions of CH4 and their higher rates. The main contribution to the increase in the concentration of H atoms in the flame in passing from a methane–air mixture to a CH4/CO/air mixture is due to the same reactions that increase the heat release rate: O + CH3 = H + CH2O and CO + OH = CO2 + H. The results obtained and their comparison with literature data lead to the conclusion that the increase in the heat release rate and, hence, the flame propagation rate should be greater in rich mixtures since there the thermophysical effect is higher.

Patients treated for traumatic brain injury (TBI) are in metabolic crises because of the trauma and underfeeding. We utilized fractional gluconeogenesis (fGNG) to assess nutritional adequacy in ad libitum-fed and calorically-restricted rats following TBI. Male Sprague–Dawley individually housed rats 49 days of age were randomly assigned into four groups: ad libitum (AL) fed control (AL-Con, sham), AL plus TBI (AL+TBI), caloric restriction (CR) control (CR-Con, sham), and CR plus TBI (CR+TBI). From days 1–7 animals were given AL access to food and water containing 6% deuterium oxide (D2O). On day 8, a pre-intervention blood sample was drawn from each animal, and TBI, sham injury, and CR protocols were initiated. On day 22, the animals were euthanized, and blood was collected to measure fGNG. Pre-intervention, there was no significant difference in fGNG among groups (p ≥ 0.05). There was a significant increase in fGNG due to caloric restriction, independent of TBI (p ≤ 0.05). In addition, fGNG may provide a real-time, personalized biomarker for assessing patient dietary caloric needs.

Thorium-234 (234Th; t1/2 = 24.1 days) has been widely used as a tracer of particle settling and organic carbon export in the ocean. However, the use of 234Th in the ocean has been hampered by labor-intensive procedures, low throughputs, and large uncertainties related to source impurities. Here, we demonstrate a more efficient technique developed to analyze 234Th in seawater by modifying the traditional Fe(OH)3 co-precipitation method. The advantages and shortcomings of this method were compared with the 234Th analytical method using MnO2 precipitation. In the new method, following the equilibration of the 230Th spike with 234Th, Th was co-precipitated with Fe. Although the precipitates include a fraction of U, Fe precipitation was fast, and the supernatant can be easily siphoned off, allowing simple handling of several samples simultaneously. The Th adsorbed onto particles, collected by Fe precipitation, was desorbed in ~ 4 M HNO3 solution by heating at 230 °C for 30 min in a sealed Teflon bottle. Then, Th was separated from U using UTEVA resin. The counting source of Th was prepared by micro-precipitation of Ce. We were able to process ~ 60 samples for 5 days onboard, and the first counting was completed within a week upon returning to the laboratory. The main advantages of this method include (1) easy increase in the sample volume, (2) rapid Fe precipitation, (3) high-purity Th sources for beta and alpha counting, (4) no need for mass spectrometry, and (5) the high throughput.

In this study, phosphate-buffered saline solution (PBS) was successfully radiolabeled with technetium-99m. The biodistribution profile and bone accumulation of the [99mTc]Tc-PBS system were evaluated in healthy swiss mice. The radiolabeling of the system was successfully obtained, yielding around 90 % of radiochemical purity. The system stability was tested in the presence of saline medium at 25 oC and mouse plasma at 37 oC, and results revealed that [99mTc]Tc-PBS showed excellent stability over time, in both media. It was observed a biphasic clearance profile, with fast elimination from the bloodstream by renal filtration. The radiolabeled system revealed a high specificity bone accumulation was observed, demonstrating an uptake behavior from 20 to 50 times higher than muscle, used as control. From all results obtained, the system constituted by [99mTc]Tc-PBS can be considered a potential selective agent for bone imaging.

International audience; In this study, drawbacks of the use of 243Am as a tracer in order to quantify curium isotopes during a complex chemical procedure were highlighted. Origins of these drawbacks were investigated through a speciation computation simulation. This simulation was based on the compilation of over 50 constants and allowed to confirm that in order to quantify curium isotopes, more reliable results are obtained using a specific curium isotope as a tracer. A new curium standard was then characterized and used to quantify a wide 244Cm activity range in environmental samples. Obtained results were in excellent agreement with spiked activities and more consistent than those obtained when using a 243Am tracer.

The study investigates the measurement of radon concentration in soils and rocks as a natural tracer for exploring uranium mineralization, first of its kind in Bangladesh. The range of radon concentration was measured as 8–4360 Bq/m3 with an average of 851.41 Bq/m3. Among the measured values, 2120–4360 Bq/m3 was observed in the Tertiary sediments whereas 8–584 Bq/m3 was found in the Recent alluvial soil of different bils and haors. These high radon concentrations are explained by geogenic factors such as mineral content in rocks, alluvium cover, sufficient porosity, probable subsurface fault, and flooding by water streamed through adjacent uranium-rich areas in India. The radon values indicate that the rock formations are promising for uranium mineralization. The radon concentration in rocks and soils are well comparable to the similar studies of the other parts of the world. The results are in good agreement with the previous radiometric survey results, suggestive to extensive exploration activities to confirm uranium mineralization in the area. Moreover, the average annual effective dose of 0.008092 mSv/y in the region calculated from the radon values is within the WHO and ICRP safety limits.

In this work, the residence time distribution (RTD) of the dispersed phase (aqueous phase) and continuous phase (organic phase) in an agitated-pulsed extraction column (APC) was measured online with a step tracer injection technique and the axial dispersion was subsequently calculated via RTD analysis. It was found that both the agitation speed and the pulsation intensity had noticeable effects on the axial dispersion of the dispersed phase, which escalates with the increase in the agitation speed and this is especially authentic at high pulsation intensity. The dispersed-phase axial dispersion coefficient also becomes higher with the increase in the dispersed-phase velocity. Compared with the dispersed-phase axial dispersion in the APC, the continuous-phase axial dispersion is 2-3 times higher. Empirical equations have been proposed to correlate the dispersed- and continuous-phase axial dispersion coefficients for variation of both agitation and pulsation conditions in APC. This study could be valuable for assessing the dispersed-phase axial dispersion in liquid-liquid extraction columns.

The development and validation of management practices to mitigate greenhouse gas (GHG) emissions from livestock require accurate emission measurements. This study assessed the accuracy of a practical inverse dispersion modelling (IDM) technique to quantify methane (CH4) emitted from a small cattle herd (16 animals) confined to a 63 m × 60 m experimental pen. The IDM technique calculates emissions from the increase in the CH4 concentration measured downwind of the animals. The measurements were conducted for 7 d. Two types of open-path (OP) gas sensors were used to measure concentration in the IDM calculation: a Fourier transform infrared spectrometer (IDM-FTIR) or a CH4 laser (IDM-Laser). The actual cattle emission rate was measured with a tracer-ratio technique using nitrous oxide (N2O) as the tracer gas. We found very good agreement between the two IDM emission estimates (308.1 ± 2.1 – mean ± SE – and 304.4 ± 8.0 g CH4 head−1 d−1 for the IDM-FTIR and IDM-Laser respectively) and the tracer-ratio measurements (301.9 ± 1.5 g CH4 head−1 d−1). This study suggests that a practical IDM measurement approach can provide an accurate method of estimating cattle emissions.

Radioactive strontium is a nuclear fission decay product found in industrial products and nuclear waste and is released during nuclear accidents. Current urine radiostrontium separation methods often are based on the use of Sr resin columns or cartridges (Eichrom Technologies). Most of these analytical methods use stable Sr as a tracer, with subsequent Sr recovery. The gravimetric recovery method requires 120 times more stable Sr than does the inductively coupled plasma mass spectrometry method described here. This difference can affect cartridge performance especially with aging cartridges.

The presence of water vapour in the input gas stream influences the performance of air electrodes of solid oxide cells. In this work, the oxygen transport kinetics were determined by isotopic exchange depth profiling at 350 °C on polycrystalline La0.6Sr0.4Co0.2Fe0.8O3-δ samples in humidified oxygen, comparing the differences in tracer diffusion profile using either 18O2 or H218O as the labelling medium. The apparent surface exchange coefficients of oxygen were determined in each case and used together to estimate the oxygen surface exchange coefficients of molecular oxygen and water. It was found that, in humid conditions, the surface exchange coefficient of molecular oxygen is significantly decreased in comparison to a reference in dry conditions. In addition, the surface exchange coefficient of water is higher than that for molecular oxygen. This is in good agreement with the hypothesis that, water monopolises the active exchange sites at the material surface and thus oxygen from water exchanges faster than the one of molecular oxygen.

The natural fractionation of stable Sr isotopes (δ88/86Sr) has attracted increasing attention as it serves as a new tracer to explore the biogeochemical process or source identification of Sr. As its applications have been expanded in various research fields, a highly efficient, accurate, and precise analytical method for δ88/86Sr determination is bound to be needed. To date, the most accurate and precise δ88/86Sr determination is performed by using the double spike (DS) technique in thermal ionization mass spectrometry (TIMS). However, TIMS suffers from long data acquisition time compared to multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). In this paper, we present a novel approach, combining the use of Zr isotope empirical external normalization (EEN) for Kr and Rb isobaric interference correction and 84Sr–87Sr DS to overcome the severe mass bias effects on the measured 88Sr/86Sr ratios, to improve the analytical accuracy of δ88/86Sr determination by MC-ICP-MS. The δ88/86Sr of the IAPSO seawater standard was determined to be 0.37‰ ± 0.03 (2SD, n = 16) with an internal precision better than ±0.01‰ (2SE). By applying this new EEN-DS MC-ICP-MS method, the accuracy is significantly improved, which is comparable to DS TIMS.

Due to their relatively high Hf contents (i.e., several hundreds to thousands of ppm), columbite-group minerals (CGMs) are suitable for Lu–Hf isotope analysis, which can provide new insights into the source of such minerals in combination with the U–Pb age of rare-metal deposits. However, few studies have reported Lu–Hf isotope data for CGMs. Tantalum is a major element in CGMs (12–48 wt% Ta2O5) and has a significant effect on measurements of Hf isotopes using MC-ICP-MS. This effect was first evaluated in this study by analysis of mixed Hf–Ta standard solutions with different Ta/Hf ratios and LA-MC-ICP-MS analysis of various CGMs. This analytical artifact reflects serious tailing of the large 181Ta signal onto the 180Hf and 179Hf masses during analysis. Therefore, in order to obtain accurate Hf isotope data for CGMs by MC-ICP-MS, we present an improved chemical separation procedure for Hf from Ta, and also a novel analytical protocol for LA-MC-ICP-MS analysis of CGMs. Accurate in situ176Hf/177Hf ratios for CGMs can be obtained by normalization to 178Hf/177Hf = 1.4672, rather than 179Hf/177Hf = 0.7325, using the exponential law. This approach was validated by solution and laser ablation MC-ICP-MS analysis of four CGM samples from China and Africa. The Lu–Hf isotopic composition of CGMs provides a new geochemical tracer for rare-metal deposits.

The effects of the size, contact-angle, and coverage of gas bubbles on solar fuels devices were characterized at cm-scale, upward-facing planar and microwire-array Si photoelectrodes in stagnant electrolytes. Experimental measurements were supported by ray-tracing simulations of surface attached gas bubble films. A dilute, redox-active tracer allowed for the quantification of the mass-transport effects of bubble coverage during photoanodic O2(g) evolution at upward-facing photoanodes in 1.0 M KOH(aq.). Measurements of the gas coverage at upward-facing p-Si photocathodes in 0.50 M H2SO4(aq.) allowed for the nucleation rate and contact angle of H2(g) bubbles to be evaluated for systems having various surface free energies. Under simulated solar illumination, the rapid departure of small O2(g) bubbles produced stable photocurrents at upward-facing oxygen-evolving Si photoanodes and yielded increased mass-transport velocities relative to a stagnant electrolyte, indicating that bubbles can provide a net benefit to the photoelectrochemical performance of an upward-facing photoanode in solar fuels devices.

LiySi is an interesting material for negative electrodes in Li-ion batteries. We carried out measurements with a galvanostatic intermittent titration technique (GITT) on ion-beam-sputtered amorphou...

We developed a mass spectrometric soil-gas flux measurement system using a portable high-resolution multi-turn time-of-flight mass spectrometer, called MULTUM, and we combined it with an automated soil-gas flux chamber for the continuous field measurement of multiple gas concentrations with a high temporal resolution. The developed system continuously measures the concentrations of four different atmospheric gases (NO2, CH4, CO2, and field soil–atmosphere flux measurements of greenhouse gases (NO2, O2) ranging over 6 orders of magnitude at one time using a single gas sample. The measurements are performed every 2.5 min with an analytical precision (2 standard deviations) of ±34 ppbv for NO2; ±170 ppbv, CH4; ±16 ppmv, CO2; and ±0.60 vol %, O2 at their atmospheric concentrations. The developed system was used for the continuous field soil–atmosphere flux measurements of greenhouse gases (NO2, CH4, and CO2) and O2 with a 1 h resolution. The minimum quantitative fluxes (2 standard deviations) were estimated via a simulation as 70.2 µgNm-2h-1 for NO2; 139 µgCm-2h-1, CH4; 11.7 mg C m−2 h−1, CO2; and 9.8 g O2 m−2 h−1, O2. The estimated minimum detectable fluxes (2 standard deviations) were 17.2 µgNm-2h-1 for NO2; 35.4 µgCm-2h-1, CH4; 2.6 mg C m−2 h−1, CO2; and 2.9 g O2 m−2 h−1, O2. The developed system was deployed at the university farm of the Ehime University (Matsuyama, Ehime, Japan) for a field observation over 5 d. An abrupt increase in NO2 flux from 70 to 682 µgNm-2h-1 was observed a few hours after the first rainfall, whereas no obvious increase was observed in CO2 flux. No abrupt NO2 flux change was observed in succeeding rainfall events, and the observed temporal responses at the first rainfall were different from those observed in a laboratory experiment. The observed differences in temporal flux variation for each gas component show that gas production processes and their responses for each gas component in the soil are different. The results of this study indicate that continuous multiple gas concentration and flux measurements can be employed as a powerful tool for tracking and understanding underlying biological and physicochemical processes in the soil by measuring more tracer gases such as volatile organic carbon, reactive nitrogen, and noble gases, and by exploiting the broad versatility of mass spectrometry in detecting a broad range of gas species.

Oxidation flow reactors (OFRs) complement environmental smog chambers as a portable, low-cost technique for exposing atmospheric compounds to oxidants such as ozone (O3), nitrate (NO3) radicals, and hydroxyl (OH) radicals. OH is most commonly generated in OFRs via photolysis of externally added O3 at λ=254 nm (OFR254) or combined photolysis of O2 and H2O at λ=185 nm plus photolysis of O3 at λ=254 nm (OFR185) using low-pressure mercury (Hg) lamps. Whereas OFR254 radical generation is influenced by [O3], [H2O], and photon flux at λ=254 nm (I254), OFR185 radical generation is influenced by [O2], [H2O], I185, and I254. Because the ratio of photon fluxes, I185:I254, is OFR-specific, OFR185 performance varies between different systems even when constant [H2O] and I254 are maintained. Thus, calibrations and models developed for one OFR185 system may not be applicable to another. To investigate these issues, we conducted a series of experiments in which I185:I254 emitted by Hg lamps installed in an OFR was systematically varied by fusing multiple segments of lamp quartz together that either transmitted or blocked λ=185 nm radiation. Integrated OH exposure (OHexp) values achieved for each lamp type were obtained using the tracer decay method as a function of UV intensity, humidity, residence time, and external OH reactivity (OHRext). Following previous related studies, a photochemical box model was used to develop a generalized OHexp estimation equation as a function of [H2O], [O3], and OHRext that is applicable for I185:I254≈0.001 to 0.1.

Recently, we produced 11 C-labeled 2-((1E,3E)-4-(6-(methylamino)pyridin-3-yl)buta-1,3-dienyl)benzo[d]thiazol-6-ol ([11 C]PBB3) as a clinically useful positron emission tomography (PET) tracer for in vivo imaging of tau pathologies in the human brain. To overcome the limitations (i.e., rapid in vivo metabolism and short half-life) of [11 C]PBB3, we further synthesized 18 F-labeled 1-fluoro-3-((2-((1E,3E)-4-(6-(methylamino)pyridine-3-yl)buta-1,3-dien-1-yl)benzo[d]thiazol-6-yl)oxy)propan-2-ol ([18 F]PM-PBB3). [18 F]PM-PBB3 is also a useful tau PET tracer for imaging tau pathologies. In this study, we developed a routine radiosynthesis and quality control testing of [18 F]PM-PBB3 for clinical applications. [18 F]PM-PBB3 was synthesized by direct 18 F-fluorination of the tosylated derivative, followed by removal of the protecting group. [18 F]PM-PBB3 was obtained with sufficient radioactivity (25 ± 6.0% of the nondecay-corrected radiochemical yield at the end of synthesis, EOS), radiochemical purity (98 ± 0.6%), and molar activity (350 ± 94 GBq/μmol at EOS; n = 53). Moreover, [18 F]PM-PBB3 consistently retained >95% of radiochemical purity for 60 min without undergoing photoisomerization using a new UV-cutoff light (yellow light) fixed in the hot cell to monitor the synthesis. All the results of the quality control testing for the [18 F]PM-PBB3 injection complied with our in-house quality control and quality assurance specifications. We have accomplished >200 production runs of [18 F]PM-PBB3 in our facility for various research purposes.

Chemical effects on the size-resolved hygroscopicity of urban aerosols were examined based on the Korea–US Air Quality Study (KORUS-AQ, 2020) field campaign data. The information on size-resolved hygroscopicity and the chemical composition of aerosols were obtained by a hygroscopic tandem differential mobility analyzer (HTDMA) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), respectively. Good correspondence was shown between measured and estimated κ values calculated from the combination of bulk chemical composition data and oxidation parameters of organic aerosols (f44 and O∕C). These results imply that chemical composition is closely associated with aerosol hygroscopicity. However, the correlation between measured and estimated κ values degraded as particle size decreased, implying that size-resolved chemical composition data are required for more detailed hygroscopicity analysis. In addition to size-resolved chemical data, the m∕z tracer method was applied for size-resolved organic factors. Specifically, m∕z 57 and 44 were used as AMS spectral markers for hydrocarbon-like organic aerosol (HOA) and oxygenated organic aerosol (OOA), respectively. These size-resolved chemical composition data were found to be critical in explaining size-dependent hygroscopicity, as well as the diurnal variation in κ for small particles, i.e., low κ in the morning and high κ in the afternoon. Additionally, aerosol mixing state information was associated with the size-resolved chemical composition data. That is to say that the relationship between the number fraction of each hygroscopicity mode and the volume fraction of different chemical composition was investigated. For example, the HOA volume fraction comprised about 60 % of the variation in less hygroscopic (LH) mode number fractions for externally mixed aerosols.

Radioactive metals are applied in biochemistry, medical diagnosis such as positron emission tomography (PET), and cancer therapy. However, the activity of radioisotopes exponentially decreases with time; therefore, rapid and reliable probe preparation methods are strongly recommended. In the present study, electrodialytic radioactive metal ion handling is studied for counter ion conversion and in-line probe synthesis. Presently, counter ion conversion and probe synthesis are achieved by evaporative dryness and solution mixing, respectively. Evaporative dryness is time-consuming and is a possible process that can lead to loss of radioactive metal ions. Mixing of solutions for synthesis makes dilution and undesirable effects of counter ion on the synthesis. An optimized electrodialytic flow device can transfer a radioisotope

This paper proposes a joint measurement method of Ra-226 and Ra-228 in water. Radium was extracted from aqueous samples and analyzed by liquid scintillation counting (LSC). The spectrum and counts measured by LSC is combined with the standard spectrum, and then the activities of Ra-226 and Ra-228 can be calculated by the stripping method. Chemical yields of radium were determined by measuring the chemical analogue (barium) tracer by atomic absorption spectrometry (AAS). The accuracy of the method was verified by measuring mixtures containing varying proportions of Ra-226 and Ra-228.

Here, we describe the development of an in-house-built device for the fully automated multistep synthesis of the cannabinoid CB1 receptor imaging tracer (3R,5R)-5-(3-([18 F]fluoromethoxy-d2 )phenyl)-3-(((R)-1-phenylethyl)amino)-1-(4-(trifluoromethyl)phenyl)pyrrolidin-2-one ([18 F]FMPEP-d2 ), following good manufacturing practices. The device is interfaced to a HPLC and a sterile filtration unit in a clean room hot cell. The synthesis involves the nucleophilic 18 F-fluorination of an alkylating agent and its GC purification, the subsequent 18 F-fluoroalkylation of a precursor molecule, the semipreparative HPLC purification of the 18 F-fluoroalkylated product, and its formulation for injection. We have optimized the duration and temperature of the 18 F-fluoroalkylation reaction and addressed the radiochemical stability of the formulated product. During the past 5 years (2013-2018), we have performed a total of 149 syntheses for clinical use with a 90% success rate. The activity yield of the formulated product has been 1.0 ± 0.4 GBq starting from 11 ± 2 GBq and the molar activity 600 ± 300 GBq/μmol at the end of synthesis.

Background In vitro experiments using radiolabeled molecules is fundamental for Positron emission tomography (PET) or single photon emission computed tomography (SPECT) tracer development and various metabolic assays, but no consensus on appropriate incubation conditions exists. Specifically, the use of shaking versus non-shaking conditions, cell number to medium volume and the choice of cell plating material may unintentionally influence cellular oxygenation and medium composition. This is problematic when testing the oxygen-dependence of tracers including 18F-fluoro-2-deoxyglucose ([18F]FDG) and hypoxia-selective 2-nitroimidazoles (e.g., 18F-fluoroazomycin-arabinoside, [18F]FAZA) or when doing prolonged experiments. The purpose of this study was to assess the influence of various experimental conditions on tracer retention. Methods Tumor cells were seeded in a) Glass or standard Polystyrene Petri dishes or as b) discrete droplets in polystyrene Petri dishes or on 9 mm glass coverslips positioned in glass Petri dishes. When confluent, cells were pre-equilibrated for 2 h to 21%, 0.5% or 0% O2 and [18F] FDG or [18F] FAZA was added, followed by cell harvest and analysis of radioactivity 1 h ([18F]FDG) or 3 h ([18F]FAZA) after. Experiments were conducted with/without orbital shaking. Results The influence of hypoxia on tracer retention varied widely among cell lines, but shaking-induced convection did not influence uptake. In contrast, hypoxia-driven [18F] FAZA, and to some extent [18F] FDG, retention was much lower in cells grown on polyethylene than glass. Scaling-down the number of cells did not compromise accuracy. Conclusions Tracer retention was similar under stagnant and forced convection conditions suggesting that the former approach may be appropriate even when accurate control of oxygen and tracer availability is required. In contrast, conventional plasticware should be used with caution when studying tracers and drugs that are metabolized and retained or activated at low O2 levels. Downscaling of cell number, by reducing the effective growth area, was feasible, without compromising accuracy.

Isotope dilution (ID) method has been widely applied to studies of elemental speciation and certification of the concentrations of geological reference materials. One of the key factors restricting the application of the ID method is the difficulty in identifying the optimal ratios of the isotope tracer (spike) to sample (S/N) and in estimating the error propagation. Here, using Se isotope as an example and employing a Monte Carlo method, we found that the optimal choice of spike and S/N are 77Sespike and 0.7, respectively. The S/N in the range from 0.1 to 4 can produce sufficiently low errors (

Previous studies have shown that significant K isotope fractionation is found in continental weathering, oceanic crust subduction, and plant growth, suggesting that K isotopes could be a potentially important tracer. However, the complicated separation method and analytical conditions limit the precise analysis of potassium isotopes via MC-ICP-MS under “cold” plasma conditions. Here, an improved separation method (single column) permits the complete purification of K from the matrix elements. This method is efficient and convenient and achieves a high yield (99.5 ± 0.6%) and low blank (

While high concentrations of pre-existing particles tend to inhibit new particle formation (NPF) in the atmosphere, severely polluted megacities around the world are becoming hot spots for the latter. We measured the particle number-size distributions with a Scanning Mobility Particle Sizer (SMPS) in the urban environment of Kanpur, India, and discovered that particle bursts occurred on 82% of the observation days, indicating that new particles frequently formed from gaseous precursors despite the relatively high concentrations of pre-existing particles. During such events, Aitken-mode particles contributed more than 50% of the total particle mass. Additionally, we used a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) to assess chemical changes in the sub-micron particles during NPF events. Because the HR-ToF-AMS can not detect particles smaller than 40 nm in diameter, however, it was not possible to investigate the chemistry driving the NPF. Our results indicated that oxygenated organic aerosols (OAs) constituted almost 77%—the largest fraction—of the sub-micron particles. The m/z 57 ion (C4H9+), a tracer of hydrocarbon-like OA (HOA), displayed significantly enhanced signal intensity during all of the NPF event days. Moreover, the increased proportion of organic ions, m/z 44 (CO2+), on these days suggested the presence of less volatile, highly oxidized OAs (LV-OOAs), revealing that the growth of new particles was mainly due to the condensation of low-volatility organic species. The substantially elevated signal intensity of amines (viz., CHN+, CH4N+, C2H4N+, C3H8N+, and C5H12N+) in the sub-micron aerosols during NPF further demonstrated that these nitrogen-containing organic compounds may have played a critical role in these events. Thus, our findings emphasize the relevance of amines to secondary aerosol formation in severely polluted urban environments.

Highlights The AIXR nozzle and modified vegetable oil reduce drift potential. Downwind spray deposition increases non-linearly as airspeed increases. Nozzle selection is more important than adjuvant to mitigate spray drift. Abstract. Spray drift is a critical concern for pesticide applications and the largest focus for its reduction has been placed on increasing droplet size. The objectives of this research were to evaluate the influence of nozzle type, adjuvant, and airspeed on the droplet spectrum and spray drift deposits from applications of glyphosate plus 2,4-D in a wind tunnel. Two studies were conducted using three 11002 nozzles types (XR, DG, and AIXR) individually attached to a one-tip boom. The working pressure was 207 kPa. The first study evaluated drift from the potassium salt of glyphosate (1260 g ae ha-1) plus 2,4-D amine (450 g ae ha-1) tank-mixed with four adjuvants (individually) sprayed at 2.2 m s-1 airspeed. A glyphosate plus 2,4-D solution with no tank-mixed adjuvants was also evaluated. The second study evaluated drift from glyphosate plus 2,4-D applications in four airspeeds (0.9, 2.2, 3.6, and 4.9 m s-1). Drift potential was determined using 2 mm monofilament line collectors and a 1,3,6,8-pyrenetetrasulfonic acid tetra sodium salt (PTSA) fluorescent tracer added to solutions, quantified by fluorometry. Nozzles and adjuvants influenced droplet size distribution of glyphosate plus 2,4-D solutions. Among the nozzles, the AIXR produced the coarsest droplets and the lowest tracer deposits (12 ηg cm-2) at 12 m downwind regardless of solution type. When nozzles were pooled, the modified vegetable oil (MVO) reduced the spray deposition by 36% at 12 m compared to the solution without adjuvant. At 4.9 m s-1 airspeed, tracer deposit at 12 m downwind was 2-fold lower when applications were made through low-drift nozzles (DG and AIXR) compared to the XR nozzle. Results suggest that drift-reducing adjuvants tested in this study may not reduce drift and nozzle selection should be considered as a more important factor than adjuvants in order to mitigate spray drift.

This study aims to develop a fast-response sulfur hexafluoride (SF6 ) measuring system, and evaluate its performance in tracer gas measurements for studying transient airborne contaminant transport. The new system is based on a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor using a quantum cascade laser. Transient SF6 tracer gas measurements were carried out in an environmental chamber with an instantaneous source using both the QEPAS system and a traditional commercial instrument. Real-time SF6 concentrations, peak SF6 concentrations and average SF6 concentrations for one room time constant under two air change rates obtained by the two instruments were compared. The results show that the QEPAS system, which features a 0.4 s data acquisition interval, can provide detailed real-time SF6 concentrations even when the concentration is changing rapidly. The QEPAS system successfully captured the peak SF6 concentrations for all the studies cases, while commercial instrument failed in most studied cases. In most of the cases, the two instruments obtained similar average SF6 concentrations for one room time constant. However, when the concentration was in rapid change, the two systems would report significantly different results. The QEPAS system can be potentially applied in transient tracer gas measurements under complex scenarios.

Deuterated water has been applied in hydrogeological tracer tests in recent years. However, there is a contradiction about the conservativeness of artificial deuterium (D/2H). In this study, what circumstances HDO behaved truly conservatively were investigated through laboratory-scale experiments via comparing the widely used tracer chloride (Cl-). And reasons for the non-conservativeness of HDO were discussed comprehensively for the first time. In addition, the advection-dispersion equation (ADE) and dual-domain mass transfer (DDMT) equation were employed to describe the breakthrough curves (BTCs) of tracers. HDO behaved conservatively when it transported in the porous media with high permeability (approximately K > 1m/d), and ADE could describe BTCs successfully. While hysteresis effect of HDO expressed in the media with low permeability. And the lower the permeability of the porous media, the stronger the hysteresis effect. DDMT was more suitable for demonstrating BTCs in low permeability media. Hydrogen bonds between HDO and H2O, the isotopic exchange effect, and the dual-domain model of the media all could lead to the hysteresis effect. The retardation factor (R = 1.712) was used to describe transporting behaviors of HDO in clay firstly. And the threshold hydraulic conductivity (Kcr) and the proportion of immobile regions of HDO were greater than that of Cl-, while dispersion coefficients of HDO were smaller. These could provide further considerations for using deuterium in hydrogeological tracer tests.

A modified community multiscale air quality model, which can simulate the regional distributions of 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a marker species for monoaromatic secondary organic aerosol (SOA), was applied to assess the applicability of using the DHOPA to aromatic SOA mass ratio (fSOA) from smog chamber experiments to estimate aromatic SOA during a three-week wintertime air quality campaign in urban Shanghai. The modeled daily DHOPA concentrations based on the chamber-derived mass yields agree well with the organic marker field measurements (R = 0.79; MFB = 0.152; and MFE = 0.440). Two-thirds of the DHOPA are from the oxidation of ARO1 (lumped less-reactive aromatic species; mostly toluene), with the rest from ARO2 (lumped more-reactive aromatic species; mostly xylenes). Modeled DHOPA is mainly in the particle phase under ambient organic aerosol (OA) loading but could exhibit significant gas-particle partitioning when a higher estimation of the DHOPA vapor pressure is used. The modeled fSOA shows a strong dependence on the OA loading when only semivolatile aromatic SOA components are included in the fSOA calculations. However, this OA dependence becomes weaker when non-volatile oligomers and dicarbonyl SOA products are considered. A constant fSOA value of ∼0.002 is determined when all aromatic SOA components are included, which is a factor of 2 smaller than the commonly applied chamber-based fSOA value of 0.004 for toluene. This model-derived fSOA value does not show much spatial variation and is not sensitive to alternative estimates of DHOPA vapor pressures and SOA yields, and thus provides an appropriate scaling factor to assess aromatic SOA from DHOPA measurements. This result helps refine the quantification of SOA attributable to monoaromatic hydrocarbons in urban environments and thereby facilitates the evaluation of control measures targeting these specific precursors.

Using 15N stable isotope as a tracer to quantify N transformation rates in isotope-enrichment experiments improves understanding of the N cycle in various ecosystems. However, measuring 15N-nitrate (15NO3−) in small volumes of water for these experiments is a major challenge due to the inconvenience of preparing samples by traditional techniques. We developed a “REOX/MIMS” method by applying membrane inlet mass spectrometry (MIMS) to determining 15NO3− concentrations in a small volumes of water from isotope-enrichment experiments after converting the dissolved inorganic N to N2. The nitrates (NO3− + NO2−) were reduced to NH4+ with zinc powder, and the ammonium (NH4+) was then oxidized to N2 by hypobromite iodine solution. The resulting 29N2 and 30N2 were measured via MIMS. This optimized protocol provides a sensitive (~0.1 μM) and precise (relative standard deviation = 0.1–4.37%) approach to quantify 15NO3− concentrations (0.1–500 µM) in water samples over a wide range of salinities (0–35‰) and in 2 M KCl solution with excellent calibration curves (R2 ≥ 0.9996, p

RATIONALE The triple oxygen isotopic composition (Δ17 O) of tropospheric ozone (O3 ) is a useful tracer for identifying the source and is essential for clarifying the atmospheric chemistry of oxidants. However, the single nitrite-coated filter method is inaccurate owing to the nitrate blank produced through the reaction of nitrite and oxygen compounds other than O3 . METHODS A multistep nitrite-coated filter-pack system is newly adopted to transfer the O-atoms in terminal positions of O3 to nitrite on each filter to determine the Δ17 O of O3 in terminal positions (denoted as Δ17 O(O3 )term ). The NO3- produced by this reaction is chemically converted into N2 O, and continuous-flow isotope ratio mass spectrometry (CF-IRMS) is used to determine the oxygen isotopic compositions. RESULTS The reciprocal of the NO3- quantities on the nitrite-coated filters in each sample showed a strong linear relationship with Δ17 O of NO3- . Using the linear relation, we corrected the changes in Δ17 O of NO3- on the filters. We verified the accuracy of the new method through the measurement of artificial O3 with known Δ17 O(O3 )term value that had been determined from the changes in Δ17 O of O2 . The Δ17 O(O3 )term of tropospheric O3 was in agreement with previous studies. CONCLUSIONS We accurately determined the δ18 O and Δ17 O values of tropospheric O3 by blank correction using our new method. Measurements of Δ17 O(O3 )term of the ambient troposphere showed 1.1 ± 0.7‰ diurnal variations between daytime (higher) and nighttime (lower) due likely to the formation of the temperature inversion layer at night.

Here we report a new procedure to determine Pu-239 in urine using a custom-made automated pre-analytical processing system (single probe) with Pu-242 as a tracer followed by analysis by SF-ICP-MS. An average Pu-242 recovery rate of 88% was obtained with CF-ThU-1000 columns reused >100 times. Analytical results agree with measurements obtained using the CDC manual method with a R(2) of 0.9994. Results for Oak Ridge National Laboratory (ORNL) reference materials (RM) align with target values with a bias range of −3.44% to 3.05%. The limit of detection for this method is 0.63 pg/L, which is comparable to previous manual methods.

Lead-210 is a useful tracer in environmental studies for a wide range of applications, particularly in atmospheric research and geochronology. Liquid scintillation counting (LSC) is a commonly used measurement method for 210Pb analysis. In the present work, to increase detection efficiency, an improved LSC technique for 210Pb determination was developed. After adding lead carrier, samples were decomposed with mineral acid in closed digestion vessels. Using extraction chromatography with Sr resin, 210Pb was selectively separated and precipitated as lead oxalate. Following re-dissolution, the solution was mixed with a scintillation cocktail and measured by a liquid scintillation counter. In this study, all the spectral regions with peaks of 210Pb, 210Bi, and 210Po were used to calculate the activity of 210Pb; this is in contrast to the existing method, which divides the spectra into three regions according to energy level, and then selects only the 210Pb region. The method in this study also addresses a procedure for correcting blank values to account for 210Pb activity in the Pb2+ carrier. This measurement technique, using the spectral regions of 210Pb, 210Bi, and 210Po, exhibited more than twice the detection efficiency of the conventional method using only the 210Pb spectrum region. This measurement technique is expected to be a useful method for 210Pb analysis of environmental samples that show low activity, and when sample amounts are limited.

Determination of long-lived radionuclides is critical for environmental radioactivity investigation, environmental processes studies and decommissioning of nuclear facilities. This paper summarizes main progress in the radiochemical analysis in our laboratories in the past years for determination of ultra-low level radionuclides in the environment using chemical separation combined with mass spectrometry measurement. The analytical methods for determination of ultra-low level 129I and its chemical species in various environmental samples are highlighted. The methods developed in our laboratories for characterization of decommissioning waste, especially the methods for the determination of difficult-to-measure radionuclides using sequentially chemical separation and radiometric measurement are also briefly presented. This is also a part of the Hevesy Medal award lecture in the RANC2019 conference.

The behavior of gaseous components of forest soil was assessed by simultaneous monitoring of 222Rn, CO2 and its carbon isotopes (δ13C, Δ14C) in soil air under a semi natural forest in northern Japan. The isotope ratio of 14C (Δ14C) in soil air CO2 was found to decrease towards late summer, suggesting gradual depletion of easily decomposed soil organic matter. There was a specific case that soil air CO2 with depleted 14C appeared suddenly under snowpack in winter. It is not always appropriate to use soil 222Rn as a tracer of CO2 efflux from the soil surface to the atmosphere.

129I is emitted continuously in large amounts by reprocessing plants in La Hague and Sellafield. For determination of mobility in soil, we provide results of column experiments with undisturbed natural soils. Directly after short-term (28 days) contact with water from the bottom, iodine shows high upwards mobility only due to capillary forces. Furthermore, desiccation of the contaminated tracer reservoir led to an even stronger migration effect, which indicates remobilization of iodine from the drying soil layers. Chemical speciation proves difficult, as either gaseous iodine or organically bound iodine attached to dissolved organic matter are possible for the upward migration processes.

The interaction of xenon with containment barriers can play a crucial role in the detection of underground nuclear explosions. Independent field experiments and laboratory-derived models have observed depressed surface level xenon concentrations and subsequently predicted geological capture rates. This work sought to experimentally verify those predictions by analyzing xenon transport though a two-bulb diffusion apparatus adapted for the study of geologic media. Novel to this work is the timescale over which these experiments were carried out, allowing the system to reach equilibrium, rather than relying on numerical models to treat the equilibrium concentration of each gas as a fit coefficient.

A novel chronometry method is developed to date irradiated nuclear fuels. It is based on the measurement of two Cm isotopic ratios (244Cm/246Cm and 245Cm/246Cm) and does not require the addition of a yield tracer. The method relies on the decay of 244Cm while the 245Cm/246Cm ratio is considered constant after irradiation. Feasibility is demonstrated using different types of irradiated fuels with known irradiation history. A precision of 5 year is reached so far but clear potential for improvement has been identified. The novel chronometry method represents a promising alternative to existing dating techniques for nuclear materials.

This paper presents the results of fluorescence-based analysis of homogeneity of five multicomponent granular mixtures. Analyses were performed using solutions of selected substances capable of emitting light following UV irradiation, namely Tinopal 0.03% and Rhodamine B 0.01%. Mixtures were spiked with the key component consisting of maize grains coated with the fluorescent solution. The tracer content was determined on the basis of computer image analysis, and the results were compared to those obtained using the traditional weighing method. On this basis, the proposed method was verified and assessed for applicability in estimating the homogeneity of mixtures comprised of 8, 10, 11, 14, and 20 components. The results suggest that both Tinopal and Rhodamine B may be used to estimate the tracer content in the tested mixtures.

Quantitative understanding of kinetics and mechanisms heavy metal adsorption-desorption and transport processes, batch and stirred-flow experiments were carried out with vanadium (V) and molybdenum (Mo) on soils at different reaction conditions and time scale. Batch experiments indicated that adsorption of V and Mo on soils was highly nonlinear and time-dependent, where V and Mo retention showed typical biphasic reaction kinetics. The stirred-flow experiments showed that both V and Mo adsorption consisted of a fast initial reaction, as indicated by the fact that effluent solute concentration was close to zero for the first few minutes. A stirred-flow multi-reaction model (MRM) which accounts for slow as well as fast reactions of the reversible and irreversible type was developed to describe V and Mo adsorption and desorption processes on soils. Based on model simulations and experimental tracer breakthrough curves (BTCs) results, we concluded that the proposed model is valid for stirred-flow conditions. The strong retardation and slow release behaviors of V and Mo from stirred-flow experiments were successfully described using the proposed stirred-flow MRM where retardation and irreversible reactions were necessary. Our work provides a general stirred-flow model which is capable of describing reactive and non-reactive solutes.

Filamentous fungi are well-established production hosts that feature a strong interconnection between morphology, physiology, and productivity. For penicillin production in Penicillium chrysogenum, industrial processes frequently favor a pellet morphology comprising compact hyphal agglomerates. Inherently these tightly packed entanglements lead to inactive, degrading sections within the pellet’s core because of limitations. Optimal process design requires detailed knowledge of the nature of the limitations and localization of productive zones in the biomass, which is generally obtainable through modeling and complex analytical methods such as oxygen microelectrode and histological investigations. Methods that combine physiological and morphological insight are crucial yet scarce for filamentous fungi. In this study, we used time-of-flight secondary ion mass spectrometry in combination with oxygen and glucose tracer substrates, requiring little effort for sample preparation and measurement. Our method is capable of analyzing oxygen and substrate uptake in various morphological structures by the use of 18O as a tracer. In parallel, we can assess productive biomass regions through identification of penicillin mass fragments to simultaneously study oxygen diffusion, substrate incorporation, and productive biomass sections.

A method intended for the mg scale separation of curium (Cm) from americium (Am) and plutonium (Pu) based on high pressure liquid chromatography using a strong cation exchange column has been investigated. Reproducible separations were achieved on the Luna SCX (Phenomenex) column with α-hydroxymethylbutyric acid (α-HMBA) as eluant. The separation performance was investigated on the tracer level varying the pH, concentration, temperature and flow rate of the eluting solution. It was found that 0.1 M α-HMBA at a pH of 3.7 using a flow-rate of 1 mL/min, gave enough peak resolution for an efficient and reproducible separation of Cm from Am. Separations with gadolinium loading were investigated to scale up the purification of Cm from tracer level to mg scale. Baseline chromatographic separations were demonstrated in column loadings of up to 20% of full column capacity, corresponding to 2.5 mg of Cm.

The spatial distribution of barium activity in granitic rocks was measured with two autoradiography techniques; digital autoradiography using phosphor imaging plate technique (Fuji 5100) and filmless electronic autoradiography (i.e. The BeaQuant (TM)), which is based on a gas detector incorporated in a micromesh Parallel Ionization Multiplier (PIM). Rock cubes taken from a diffusion experiment that were in contact with Ba-133 tracer were measured to determine diffusion profiles. In addition, the spatial distribution of Ba-133 in the samples was determined. Polymethyl methacrylate standards for Ba-133 were developed to determine the counting efficiency for electronic autoradiography. Good visual correlation between the two autoradiography methods were obtained in this study. The results of the experiments presented here can be utilized in future studies on the diffusion behavior of barium in granitic rocks.

This work presents a method developed for simultaneous analysis of ultra-trace level 237Np and Pu isotopes in soil and sediment samples by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). 242Pu was used as a yield tracer for 237Np as well as for Pu isotopes. A simple single chromatographic column packed with anion exchange resin (AG MP-1M) was used for the separation of 237Np and Pu isotopes from the matrix elements and other potential interferences. The SF-ICP-MS measurement precision of the 237Np/242Pu atom ratio for sub-fg/mL level 237Np and 242Pu was 0.97%, and the overall fractionation between 237Np and 242Pu for the whole analysis procedure was 1.010 ± 0.038. Besides, the single column chromatographic separation realized high decontamination factor of U (1.8 × 106 to 1.7 × 107), and that ensured the interference effect of 238U to the 237Np, 239Pu and 240Pu measurements was negligible or could be easily corrected. Four standard reference materials were analyzed for method validation, and the results illustrated 242Pu was an effective non-isotopic tracer for 237Np determination. Finally, the developed method was successfully employed in the analysis of the global fallout level of 237Np and Pu isotopes in Japanese paddy soil samples to study their environmental behaviors.

The present paper describes a relatively simple, effective, very selective and economic method for the determination of uranium in calcite and (phospho)gypsum samples. The analysis is performed by alpha-spectroscopy after dissolution of the samples in Na2-EDTA solution, uranium separation by cation-exchange and its electrodeposition on stainless steel discs. The method has been applied to 1 g limestone, chalk and (phospho)gypsum samples, resulting in high-quality spectra for measurement times between 6 and 72 h. The separation efficiency of the method is (75 ± 10)% and (65 ± 20)%, and the detection limit 0.2 mBq g−1 (4 mg kg−1) and 0.3 mBq g−1 (6 mg kg−1), for the gypsum and calcite samples, respectively. Moreover, the use of tracer solution (232U) allows method evaluation and accurate uranium determinations. 320 3 807 812