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Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40 t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay ( 0 ν β β ), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We present here the results of simulations performed to determine the production rate of 137 Xe, the most crucial isotope in the search for 0 ν β β of 136 Xe. Additionally, we explore the contribution that other muon-induced spallation products, such as other unstable xenon isotopes and tritium, may have on the cosmogenic background. [ABSTRACT FROM AUTHOR]

In this paper, the optimization of the square and squared-off cascades for the separation of stable isotopes with a certain number of gas centrifuges (GCs) using particle swarm optimization (PSO) and the whale optimization algorithm (WOA) was studied. For this purpose, the "SC-PSO" and "SC-WOA" codes for the square cascade (SC), and the "SOC-PSO" and "SOC-WOA" codes for the squared-off cascade (SOC) were developed. The performance of the PSO and WOA algorithms in the optimization of the square and squared-off cascades as an example for the separation of 124Xe from nine stable isotopes of xenon up to an enrichment of 85% was compared. The recovery coefficient of 124Xe isotope by the codes "SC-PSO", "SC-WOA", "SOC-PSO", and "SOC-WOA" was obtained 86.14, 78.11, 92.84, and 83.41% respectively. The performance of the algorithms indicates the higher yield of the PSO algorithm in the optimization of SC and SOC. The efficiency of the PSO has been demonstrated by the Griewank test function compared with the WOA, the sine cosine algorithm (SCA), and the dragon-fly algorithm (DA) (PSO>WOA>SCA>DA). Furthermore, the results show that SOC performs better than SC. [ABSTRACT FROM AUTHOR]

The positive-parity states of even–even Xe nuclei are inspected within the framework of modified (6) limit of the interacting boson model (IBM). The effective three-body interaction where is the IBM (6) quadrupole operator is introduced to exhibit the triaxiality nature. The shape of nuclear surface is quantified by the deformation parameters , by using the intrinsic coherent state. For each nucleus, the potential energy surfaces (PES) of the transition (5)–Triaxiality– (6) are resolved and analyzed and the critical phase transition points are identified. For each nucleus a fitting procedure is adopted to get the best model parameters by fitting some selected calculated energy levels and transition rate ratios with experimental ones. These ratios are analyzed because they serve as effective order parameters in the shape phase transition. The nuclei in Xe isotopic chain evolve from spherical vibrator (5) to -soft rotor (6) by increasing the boson number from (heavy isotope Xe) to (light isotope Xe) and the isotope Xe represents the critical nucleus. The nucleus Xe has triaxial nature. To transact with high spin states in -band in Xe isotopic chain to investigate and exhibit the odd–even-spin energy staggering, we introduce the two-parameter collective nuclear softness rotor model (CNS2). Three different staggering indices are considered depending on the dipole transitions linking the two families of spins while the quadrupole transitions are within each spin family. Strong odd–even-spin energy staggering has been seen. As a link between the IBM and CNS2 models we observed that the energy difference between the -band and ground state band normalized to decreases with increasing the mass number. [ABSTRACT FROM AUTHOR]

Mathematical techniques for modeling and simulating dangerous or complex systems, such as nuclear technology systems, often require high-performance computing to process and analyze available data. In this paper, simple and quick method to support studies and research related to nuclear fuel is presented. This reasonably simple method helps to predict different concentrations of actinides and fission products in nuclear fuels without the need for expensive specialized programs and highly-trained researchers. The great importance of this approach is the speed of predicting the components of nuclear fuel concentrations, which in turn leads to quick decision-making, such as the possibility of operating fuel at higher burnup values, predicting the amount of gases resulting from nuclear fission (which may accumulate and cause problems in nuclear fuel such as volume swells), and other important decisions in nuclear fuel technology. The predicted equations have been generalized for higher values of burnup and compared with comparable results from MCNP codes. The equations deduced in calculating the different concentrations of xenon and krypton isotopes resulting from fission in burnup of nuclear fuel showed very precise results with discrepancies (magnitude of an error between the data points and the corresponding predicted ones) less than 2%. The suggested method offers a great advantage for researchers, which are the use one of any simple or common computational programs available to most researchers and do not need much experience to deal with, such as MATLAB, Excel that are easy to use for regression analyses. In this paper, the advantages of the proposed method are explained along with the limitations of its use. [ABSTRACT FROM AUTHOR]

Isotopic ratios of radioxenons sampled in the atmosphere or subsurface can be used to verify the occurrence of an underground nuclear explosion (UNE). Differences in the half-lives of radioactive xenon precursors and their decay-chain networks produce different time-dependent concentration profiles of xenon isotopes allowing isotopic ratios to be used for tracking UNE histories including estimating the time of detonation. In this study, we explore the potential effects of post-detonation cavity processes: precipitation of iodine precursors, gas seepage, and prompt venting on radioxenon isotopic evolution which influences UNE histories. Simplified analytical models and closed-form solutions yielding a potentially idealized radioactive decay/ingrowth chain in a closed and well-mixed system typically have limited application by not including the partitioning of the radionuclide inventory between a gas phase and rock melt created by the detonation and by ignoring gas transport from the cavity to host rock or ground surface. In reality, either subsurface transport or prompt release that is principally responsible for gas signatures violates the closed-system (or batch-mode) assumption. A closed-form solution representing time-dependent source-term activities is extended by considering the cavity partitioning process, slow seepage, and/or prompt release of gases from the cavity and applied to realistic systems. [ABSTRACT FROM AUTHOR]

Advancement of hyperpolarized 129 Xe MRI technology toward clinical settings demonstrates the considerable interest in this modality for diagnostic imaging. The number of contrast agents, termed biosensors, for 129 Xe MRI that respond to specific biological targets, has grown and diversified. Directly functionalized xenon-carrying macrocycles, such as the large family of cryptophane-based biosensors, are good for localization-based imaging and provide contrast before and after binding events occur. Noncovalently functionalized constructs, such as cucurbituril- and cyclodextrin-based biosensors, benefit from commercial availability and optimal exchange dynamics for CEST imaging. In this work, we report the first directly functionalized cucurbituril used as a xenon biosensor. Biotinylated cucurbit[7]uril (btCB7) gives rise to a 129 Xe hyperCEST response at the unusual shift of δ=28 ppm when bound to its protein target with substantial CEST contrast. We posit that the observed chemical shift is due to the deformation of btCB7 upon binding to avidin, caused by proximity to the protein surface. Conformational searches and molecular dynamics (MD) simulations support this hypothesis. This construct combines the strengths of both families of biosensors, enables a multitude of biological targets through avidin conjugation, and demonstrates the advantages of functionalized cucurbituril-based biosensors.

The features of multistage enrichment of stable xenon isotopes in a cascade with a specified number of gas centrifuges in stages are considered. A computational experiment on xenon separation in a cascade of gas centrifuges is carried out. A procedure for calculation by the slices of partial flows of stages taking into account the dependence of their separation factors on the feed flow and split ratio is used. The parameters of the cascades and stages providing production of highly concentrated xenon isotopes with different mass numbers according to the nine-stage separation scheme are determined. [ABSTRACT FROM AUTHOR]

Stable and unstable isotopes of the heavy noble gas xenon find use in various medical applications. However, apart from 133 Xe, used for Single Photon Emission Computed Tomography, radioactive isotopes of xenon are currently complicated to obtain in small quantities. With the GAMMA-MRI project in mind, we investigated a thermal sublimation generator of the long-lived excited state (isomer) 131 m Xe. This production method utilized the decay of 131 I, obtained commercially from a hospital supplier in the form of Na 131 I powder. Heat treatments of the Na 131 I powder and cryogenic trapping of released 131 m Xe allowed us to collect up to 88% of the produced xenon. Our method provides an isomeric mixture of 131 m Xe and 131 Xe. With improvements in scalability and chemical purification, this method could be a cost-effective source of 131 m Xe for small-scale experiments. [ABSTRACT FROM AUTHOR]

In this paper, the preparation of some isotopically selected targets by ion implantation is described. The selected isotopes to be implanted over graphite matrices described in the present work were 127I and 81Br. These isotopes were chosen for their similarity with the xenon and krypton isotopes of interest for the study of Double Charge Exchange reactions in the NUMEN project (Nuclear Matrix Elements for the Neutrino-less double beta decay). The characterization of the resulting targets after implantation was carried out using Rutherford Back Scattering Spectroscopy (RBS) with 1H, 12C, 28Si beams at different energies and scattering angles. [ABSTRACT FROM AUTHOR]

We report the effect of N2 gas‐mixing in the xenon electron cyclotron resonance (ECR) plasma, and abundance‐dependent novel, exciting and unusual trends of the isotope anomaly. The xenon plasma was produced using a 10 GHz all‐permanent‐magnet NANOGAN ECR ion source, and the charge state distributions of naturally abundant six stable xenon isotopes with and without N2 gas‐mixing (at 25%, 50%, and 75%) were recorded. The intensity ratio of the heavier to lighter isotope, where the heavier isotope is less abundant, showed a clear signature of the isotope anomaly as explained by the linear Landau wave damping theory. Contrary to the theoretical prediction that the isotope anomaly should vanish with a relatively large fraction of the heavier isotope in mixed plasmas, the trends of intensity ratios observed in such cases are very unusual and have almost the mirror‐symmetrical shapes of those trends recorded with less abundant heavier isotope. Further, the effect of relative mass difference on the isotope anomaly was also evidenced. The N2 gas‐mixing of the xenon plasma at 25% and 50% shifted the entire charge state distribution toward the higher intensity side owing to the supply of additional electrons that caused high ionization efficiency. However, a prominent gas‐mixing effect was observed at 75% of N2 mixing in the xenon plasma beyond the +7 charge state. The abundance‐dependent unusual trends in isotope anomaly have been explained by considering different ionic temperatures, ion heating by the wave damping, and Coulomb scattering in the core of the plasma. [ABSTRACT FROM AUTHOR]

Recently, values for the Kumar quadrupole deformation parameters of the nucleus 130 Xe have been computed from the results of a Coulomb excitation experiment, indicating that this xenon isotope has a prominent triaxial ground state. Within a different context, it was recently argued that the analysis of particle correlations in the final states of ultra-relativistic heavy-ion collisions performed at the Large Hadron Collider (LHC) points to a similar structure for the adjacent isotope, 129 Xe. In the present work, we report on state-of-the-art multi-reference energy density functional calculations that combine projection on proton and neutron number as well as angular momentum with shape mixing for the three isotopes 128 , 129 , 130 Xe using the Skyrme-type pseudo-potential SLyMR1. Exploring the triaxial degree of freedom, we demonstrate that the ground states of all three isotopes display a very pronounced triaxial structure. Moreover, comparison with experimental results shows that the calculations reproduce fairly well the low-energy excitation spectrum of the two even-mass isotopes. By contrast, the calculation of 129 Xe reveals some deficiencies of the effective interaction. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate 3D gas-exchange functional imaging characteristics using 129 Xe MRI in a group of study participants with chronic hypersensitivity pneumonitis (CHP) as compared with healthy control participants., Methods: In this prospective study, 11 participants with clinical and CT findings of CHP (4M 7F, mean age 67 ± 6.1 years) as well as 41 healthy subjects (25M 16F, mean age 44 ± 18 years) were enrolled between 2017 and 2022 and underwent 129 Xe MRI. Three-dimensional images of ventilation, interstitial membrane uptake, and RBC transfer were rendered into quantitative 3D maps relative to a healthy reference cohort. In addition, 129 Xe spectroscopy was used to assess the RBC:membrane ratio (RBC:M), the oxygen-dependent RBC chemical shift, and cardiogenically-driven RBC oscillation amplitude. Differences between the CHP participants and healthy subjects were assessed using the two-sample t-test or Wilcoxon rank-sum test as appropriate., Results: CHP participants demonstrated significant differences in 6 parameters (p < 0.001) including regions of reduced ventilation, increased membrane uptake, and reduced RBC transfer as compared to healthy subjects. Gas exchange abnormalities measured on spectroscopy included a reduced RBC:M, reduced RBC chemical shift, and increased RBC oscillation amplitude., Conclusion: In participants with CHP, 129 Xe MRI demonstrated gas exchange abnormalities common to other fibrotic lung diseases including increased membrane uptake, deficits in RBC transfer, and reduced RBC:M. However, CHP participants also exhibited prominent ventilation abnormalities, which may be reflective of the airway-centric nature of the disease. Further, the high variability observed in the membrane uptake could suggest varying degrees of disease progression or activity., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Bastiaan Driehuys reports a relationship with Polarean that includes: consulting or advisory and equity or stocks. David Mummy reports a relationship with Polarean that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: To comprehensively assess the impact of aging, cigarette smoking, and chronic obstructive pulmonary disease (COPD) on pulmonary physiology using 129 Xe MR., Methods: A total of 90 subjects were categorized into four groups, including healthy young (HY, n = 20), age-matched control (AMC, n = 20), asymptomatic smokers (AS, n = 28), and COPD patients (n = 22). 129 Xe MR was utilized to obtain pulmonary physiological parameters, including ventilation defect percent (VDP), alveolar sleeve depth (h), apparent diffusion coefficient (ADC), total septal wall thickness (d), and ratio of xenon signal from red blood cells and interstitial tissue/plasma (RBC/TP)., Results: Significant differences were found in the measured VDP (p = 0.035), h (p = 0.003), and RBC/TP (p = 0.003) between the HY and AMC groups. Compared with the AMC group, higher VDP (p = 0.020) and d (p = 0.048) were found in the AS group; higher VDP (p < 0.001), d (p < 0.001) and ADC (p < 0.001), and lower h (p < 0.001) and RBC/TP (p < 0.001) were found in the COPD group. Moreover, significant differences were also found in the measured VDP (p < 0.001), h (p < 0.001), ADC (p < 0.001), d (p = 0.008), and RBC/TP (p = 0.032) between the AS and COPD groups., Conclusion: Our findings indicate that pulmonary structure and functional changes caused by aging, cigarette smoking, and COPD are various, and show a progressive deterioration with the accumulation of these risk factors, including cigarette smoking and COPD., Clinical Relevance Statement: Pathophysiological changes can be difficult to comprehensively understand due to limitations in common techniques and multifactorial etiologies. 129 Xe MRI can demonstrate structural and functional changes caused by several common factors and can be used to better understand patients' underlying pathology., Key Points: Standard techniques for assessing pathophysiological lung function changes, spirometry, and chest CT come with limitations. 129 Xe MR demonstrated progressive deterioration with accumulation of the investigated risk factors, without these limitations. 129 Xe MR can assess lung changes related to these risk factors to stage and evaluate the etiology of the disease., (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Purpose: To characterize the dependence of Xe-MRI gas transfer metrics upon age, sex, and lung volume in a group of healthy volunteers., Methods: Sixty-five subjects with no history of chronic lung disease were assessed with 129 Xe-MRI using a four-echo 3D radial spectroscopic imaging sequence and a dose of xenon titrated according to subject height that was inhaled from a lung volume of functional residual capacity (FRC). Imaging was repeated in 34 subjects at total lung capacity (TLC). Regional maps of the fractions of dissolved xenon in red blood cells (RBC), membrane (M), and airspace (Gas) were acquired at an isotropic resolution of 2 cm, from which global averages of the ratios RBC:M, RBC:Gas, and M:Gas were computed., Results: Data from 26 males and 36 females with a median age of 43 y (range: 20-69 y) were of sufficient quality to analyze. Age (p = 0.0006) and sex (p < 0.0001) were significant predictors for RBC:M, and a linear regression showed higher values and steeper decline in males: RBC:M(Males) = -0.00362 × Age + 0.60 (p = 0.01, R 2  = 0.25); RBC:M(Females) = -0.00170 × Age + 0.44 (p = 0.02, R 2  = 0.15). Similarly, age and sex were significant predictors for RBC:Gas but not for M:Gas. RBC:M, M:Gas and RBC:Gas were significantly lower at TLC than at FRC (plus inhaled volume), with an average 9%, 30% and 35% decrease, respectively., Conclusion: Expected age and sex dependence of pulmonary function concurs with 129 Xe RBC:M imaging results, demonstrating that these variables must be considered when reporting Xe-MRI metrics. Xenon doses and breathing maneuvers should be controlled due to the strong dependence of Xe-MRI metrics upon lung volume., (© 2024 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Introduction: Dissolved-phase 129 Xe MRI metrics suggest that gas diffusion may be more compromised at submaximal lung inflation compared to maximal inflation. We hypothesized that this diffusion deficit could be detected by comparing the carbon monoxide transfer coefficient (Kco) at submaximal lung inflation to that measured routinely at total lung capacity (TLC)., Methods: Asthma and COPD patients performed carbon monoxide diffusion tests, first at maximal lung inflation for routine Kco and alveolar volume VA and then, at a 30 % reduced inflation (redux; obtaining Kco redux and VA redux ). At both inflations mixing efficiency was determined as VA/TLC and VA redux /TLC redux to examine a potential effect on Kco redux /Kco behavior., Results: In normal subjects (n=36), median Kco redux /Kco amounted to 130 [IQR:122-136]% as expected for normal Kco recruitment response. However, 60 % of asthma patients (49/83) and 80 % of COPD patients (44/55) showed reduced Kco recruitment at submaximal inflation (Kco redux /Kco<122 %). In the asthma group, with otherwise normal routine Kco, Kco redux /Kco was significantly correlated with RV/TLC ratio (r=-0.53;P<0.001), but not with VA/TLC. In COPD patients, all with abnormal routine Kco, abnormal Kco redux /Kco response occurred in those patients with lower FEV 1 , higher RV/TLC and lower VA/TLC (P<0.01 for all)., Conclusion: Sizeable portions of COPD and asthma patients showed a lack of normal Kco recruitment at submaximal lung inflation, related to high RV/TLC. In asthma, this was the case despite normal Kco at full lung inflation, suggesting that hyperinflation at lung volumes less than TLC affects the carbon monoxide diffusion rate constant by distorting pulmonary capillaries and alveolar-capillary membranes., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pathophysiologic changes in lung diseases are often accompanied by changes in ventilation and gas exchange. Comprehensive evaluation of lung function cannot be obtained through chest X-ray and computed tomography. Proton-based lung MRI is particularly challenging due to low proton density within the lung tissue. In this review, we discuss an emerging technology--hyperpolarized gas MRI with inhaled 129 Xe, which provides functional and microstructural information and has the potential as a clinical tool for detecting the early stage and progression of certain lung diseases. We review the hyperpolarized 129 Xe MRI studies in patients with a range of pulmonary diseases, including chronic obstructive pulmonary disease, asthma, cystic fibrosis, pulmonary hypertension, radiation-induced lung injury and interstitial lung disease, and the applications of artificial intelligence were reviewed as well., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: It remains difficult to predict longitudinal outcomes in long-COVID, even with chest CT and functional MRI. 129 Xe MRI reflects airway dysfunction, measured using ventilation defect percent (VDP) and in long-COVID patients, MRI VDP was abnormal, suggestive of airways disease. While MRI VDP and quality-of-life improved 15-month post-COVID infection, both remained abnormal. To better understand the relationship of airways disease and quality-of-life improvements in patients with long-COVID, we extracted 129 Xe ventilation MRI textures and generated machine-learning models in an effort to predict improved quality-of-life, 15-month post-infection., Materials and Methods: Long-COVID patients provided written-informed consent to 3-month and 15-month post-infection visits. Pyradiomics was used to extract 129 Xe ventilation MRI texture features, which were ranked using a Random-Forest classifier. Top-ranking features were used in classification models to dichotomize patients based on St. George's Respiratory Questionnaire (SGRQ) score improvement greater than the minimal-clinically-important-difference (MCID). Classification performance was evaluated using the area under the receiver-operator-characteristic-curve (AUC), sensitivity, and specificity., Results: 120 texture features were extracted from 129 Xe ventilation MRI in 44 long-COVID participants (54 ± 14 years), including 30 (52 ± 12 years) with ΔSGRQ≥MCID and 14 (58 ± 18 years) with ΔSGRQ129 Xe MRI ventilation textures explained improved SGRQ-scores 12 months later, and outperformed clinical models. Their unique spatial-intensity information helps build our understanding about long-COVID airway dysfunction., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Grace Parraga reports financial support was provided by Ontario Ministry of Health and Long-Term Care. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale: Cystic Fibrosis (CF) progresses through recurrent infection and inflammation, causing permanent lung function loss and airway remodeling. CT scans reveal abnormally low-density lung parenchyma in CF, but its microstructural nature remains insufficiently explored due to clinical CT limitations. To this end, diffusion-weighted 129 Xe MRI is a non-invasive and validated measure of lung microstructure. In this work, we investigate microstructural changes in people with CF (pwCF) relative to age-matched, healthy subjects using comprehensive imaging and analysis involving pulmonary-function tests (PFTs), and 129 Xe MRI., Methods: 38 healthy subjects (age 6-40; 17.2 ± 9.5 years) and 39 pwCF (age 6-40; 15.6 ± 8.0 years) underwent 129 Xe-diffusion MRI and PFTs. The distribution of diffusion measurements (i.e., apparent diffusion coefficients (ADC) and morphometric parameters) was assessed via linear binning (LB). The resulting volume percentages of bins were compared between controls and pwCF. Mean ADC and morphometric parameters were also correlated with PFTs., Results: Mean whole-lung ADC correlated significantly with age (P < 0.001) for both controls and CF, and with PFTs (P < 0.05) specifically for pwCF. Although there was no significant difference in mean ADC between controls and pwCF (P = 0.334), age-adjusted LB indicated significant voxel-level diffusion (i.e., ADC and morphometric parameters) differences in pwCF compared to controls (P < 0.05)., Conclusions: 129 Xe diffusion MRI revealed microstructural abnormalities in CF lung disease. Smaller microstructural size may reflect compression from overall higher lung density due to interstitial inflammation, fibrosis, or other pathological changes. While elevated microstructural size may indicate emphysema-like remodeling due to chronic inflammation and infection., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Matthew M. Willmering, Jason C. Woods, and Laura L. Walkup are consultants to Polarean., (Copyright © 2024 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Purpose: To demonstrate the feasibility of zigzag sampling for 3D rapid hyperpolarized 129 Xe ventilation MRI in human., Methods: Zigzag sampling in one direction was combined with gradient-recalled echo sequence (GRE-zigzag-Y) to acquire hyperpolarized 129 Xe ventilation images. Image quality was compared with a balanced SSFP (bSSFP) sequence with the same spatial resolution for 12 healthy volunteers (HVs). For another 8 HVs and 9 discharged coronavirus disease 2019 subjects, isotropic resolution 129 Xe ventilation images were acquired using zigzag sampling in two directions through GRE-zigzag-YZ. 129 Xe ventilation defect percent (VDP) was quantified for GRE-zigzag-YZ and bSSFP acquisitions. Relationships and agreement between these VDP measurements were evaluated using Pearson correlation coefficient (r) and Bland-Altman analysis., Results: For 12 HVs, GRE-zigzag-Y and bSSFP required 2.2 s and 10.5 s, respectively, to acquire 129 Xe images with a spatial resolution of 3.96 × 3.96 × 10.5 mm 3 . Structural similarity index, mean absolute error, and Dice similarity coefficient between the two sets of images and ventilated lung regions were 0.85 ± 0.03, 0.0015 ± 0.0001, and 0.91 ± 0.02, respectively. For another 8 HVs and 9 coronavirus disease 2019 subjects, 129 Xe images with a nominal spatial resolution of 2.5 × 2.5 × 2.5 mm 3 were acquired within 5.5 s per subject using GRE-zigzag-YZ. VDP provided by GRE-zigzag-YZ was strongly correlated (R 2  = 0.93, p < 0.0001) with that generated by bSSFP with minimal biases (bias = -0.005%, 95% limit-of-agreement = [-0.414%, 0.424%])., Conclusion: Zigzag sampling combined with GRE sequence provides a way for rapid 129 Xe ventilation imaging., (© 2024 International Society for Magnetic Resonance in Medicine.)

Sensitivity analysis enables the identification of influential parameters and the optimisation of model composition. Such methods have not previously been applied systematically to models describing hyperpolarised 129 Xe gas exchange in the lung. Here, we evaluate the current 129 Xe gas exchange models to assess their precision for identifying alterations in pulmonary vascular function and lung microstructure. We assess sensitivity using established univariate methods and scatter plots for parameter interactions. We apply them to the model described by Patz et al and the Model of Xenon Exchange (MOXE), examining their ability to measure: i) importance (rank), ii) temporal dependence and iii) interaction effects of each parameter across healthy and diseased ranges. The univariate methods and scatter plot analyses demonstrate consistently similar results for the importance of parameters common to both models evaluated. Alveolar surface area to volume ratio is identified as the parameter to which model signals are most sensitive. The alveolar-capillary barrier thickness is identified as a low-sensitivity parameter for the MOXE model. An acquisition window of at least 200 ms effectively demonstrates model sensitivity to most parameters. Scatter plots reveal interaction effects in both models, impacting output variability and sensitivity. Our sensitivity analysis ranks the parameters within the model described by Patz et al and within the MOXE model. The MOXE model shows low sensitivity to alveolar-capillary barrier thickness, highlighting the need for designing acquisition protocols optimised for the measurement of this parameter. The presence of parameter interaction effects highlights the requirement for care in interpreting model outputs., (© 2024 GSK and The Author(s). NMR in Biomedicine published by John Wiley & Sons Ltd.)

Purpose: To evaluate the feasibility and utility of a deep learning (DL)-based reconstruction for improving the SNR of hyperpolarized 129 Xe lung ventilation MRI., Methods: 129 Xe lung ventilation MRI data acquired from patients with asthma and/or chronic obstructive pulmonary disease (COPD) were retrospectively reconstructed with a commercial DL reconstruction pipeline at five different denoising levels. Quantitative imaging metrics of lung ventilation including ventilation defect percentage (VDP) and ventilation heterogeneity index (VH I ) were compared between each set of DL-reconstructed images and alternative denoising strategies including: filtering, total variation denoising and higher-order singular value decomposition. Structural similarity between the denoised and original images was assessed. In a prospective study, the feasibility of using SNR gains from DL reconstruction to allow natural-abundance xenon MRI was evaluated in healthy volunteers., Results: 129 Xe ventilation image SNR was improved with DL reconstruction when compared with conventionally reconstructed images. In patients with asthma and/or COPD, DL-reconstructed images exhibited a slight positive bias in ventilation defect percentage (1.3% at 75% denoising) and ventilation heterogeneity index (˜1.4) when compared with conventionally reconstructed images. Additionally, DL-reconstructed images preserved structural similarity more effectively than data denoised using alternative approaches. DL reconstruction greatly improved image SNR (greater than threefold), to a level that 129 Xe ventilation imaging using natural-abundance xenon appears feasible., Conclusion: DL-based image reconstruction significantly improves 129 Xe ventilation image SNR, preserves structural similarity, and leads to a minor bias in ventilation metrics that can be attributed to differences in the image sharpness. This tool should help facilitate cost-effective 129 Xe ventilation imaging with natural-abundance xenon in the future., (© 2024 GE Healthcare and The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

We report a (129)Xe NMR relaxation-based sensing approach that exploits changes in the bulk xenon relaxation rate induced by slowed tumbling of a cryptophane-based sensor upon target binding. The amplification afforded by detection of the bulk dissolved xenon allows sensitive detection of targets. The sensor comprises a xenon-binding cryptophane cage, a target interaction element, and a metal chelating agent. Xenon associated with the target-bound cryptophane cage is rapidly relaxed and then detected after exchange with the bulk. Here we show that large macromolecular targets increase the rotational correlation time of xenon, increasing its relaxation rate. Upon binding of a biotin-containing sensor to avidin at 1.5 μM concentration, the free xenon T2 is reduced by a factor of 4.

Recent work has shown that xenon chemical shifts in cryptophane-cage sensors are affected when tethered chelators bind to metals. Here, we explore the xenon shifts in response to a wide range of metal ions binding to diastereomeric forms of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) linked to cryptophane-A. The shifts induced by the binding of Ca(2+) , Cu(2+) , Ce(3+) , Zn(2+) , Cd(2+) , Ni(2+) , Co(2+) , Cr(2+) , Fe(3+) , and Hg(2+) are distinct. In addition, the different responses of the diastereomers for the same metal ion indicate that shifts are affected by partial folding with a correlation between the expected coordination number of the metal in the DOTA complex and the chemical shift of (129) Xe. These sensors may be used to detect and quantify many important metal ions, and a better understanding of the basis for the induced shifts could enhance future designs.

Introduction: This meta-analysis aims to evaluate the agreement and correlation between phase-resolved functional lung MRI (PREFUL MRI) and dynamic contrast-enhanced (DCE) MRI in evaluating perfusion defect percentage (QDP), as well as the agreement between PREFUL MRI and 129 Xe MRI in assessing ventilation defect percentage (VDP)., Method: A systematic search was conducted in the Medline, Embase and Cochrane Library databases to identify relevant studies comparing QDP and VDP measured by DCE MRI and 129 Xe MRI compared with PREFUL MRI. Meta-analytical techniques were applied to calculate the pooled weighted bias, limits of agreement (LOA) and correlation coefficient. The publication bias was assessed using Egger's regression test, while heterogeneity was assessed using Cochran's Q test and Higgins I 2 statistic., Results: A total of 399 subjects from 10 studies were enrolled. The mean difference and LOA were -2.31% (-8.01% to 3.40%) for QDP and 0.34% (-4.94% to 5.62%) for VDP. The pooled correlations (95% CI) were 0.65 (0.55 to 0.73) for QDP and 0.72 (0.61 to 0.80) for VDP. Furthermore, both QDP and VDP showed a negative correlation with forced expiratory volume in 1 s (FEV 1 ). The pooled correlation between QDP and FEV 1 was -0.51 (-0.74 to -0.18), as well as between VDP and FEV 1 was -0.60 (-0.73 to -0.44)., Conclusions: PREFUL MRI is a promising imaging for the assessment of lung function, as it demonstrates satisfactory deviations and LOA when compared with DEC MRI and 129 Xe MRI., Prospero Registration Number: CRD42023430847., Competing Interests: Competing interests: CZ was employed by Siemens Healthineers., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale and Objectives: Emergent evidence in several respiratory diseases supports translational potential for Phase-Resolved Functional Lung (PREFUL) MRI to spatially quantify ventilation but its feasibility and physiological relevance have not been demonstrated in patients with asthma. This study compares PREFUL-derived ventilation defect percent (VDP) in severe asthma patients to healthy controls and measures its responsiveness to bronchodilator therapy and relation to established measures of airways disease., Materials and Methods: Forty-one adults with severe asthma and seven healthy controls performed same-day free-breathing 1 H MRI, 129 Xe MRI, spirometry, and oscillometry. A subset of participants (n = 23) performed chest CT and another subset of participants with asthma (n = 19) repeated 1 H MRI following the administration of a bronchodilator. VDP was calculated for both PREFUL and 129 Xe MRI. Additionally, the percent of functional small airways disease was determined from CT parametric response maps (PRM fSAD )., Results: PREFUL VDP measured pre-bronchodilator (19.1% [7.4-43.3], p = 0.0002) and post-bronchodilator (16.9% [6.1-38.4], p = 0.0007) were significantly greater than that of healthy controls (7.5% [3.7-15.5]) and was significantly decreased post-bronchodilator (from 21.9% [10.1-36.9] to 16.9% [6.1-38.4], p = 0.0053). PREFUL VDP was correlated with spirometry (FEV 1 % pred : r = -0.46, p = 0.0023; FVC% pred : r = -0.35, p = 0.024, FEV 1 /FVC: r = -0.46, p = 0.0028), 129 Xe MRI VDP (r = 0.39, p = 0.013), and metrics of small airway disease (CT PRM fSAD : r = 0.55, p = 0.021; Xrs 5 Hz : r = -0.44, p = 0.0046, and AX: r = 0.32, p = 0.044)., Conclusion: PREFUL-derived VDP is responsive to bronchodilator therapy in asthma and is associated with measures of airflow obstruction and small airway dysfunction. These findings validate PREFUL VDP as a physiologically relevant and accessible ventilation imaging outcome measure in asthma., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sarah Svenningsen reports financial support was provided by Canada Research Chairs program. Parameswaran Nair reports financial support was provided by Frederick E. Hargreave Teva Innovation Chair in Airways Disease. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Although hyperpolarized (HP) 129 Xe ventilation MRI can be carried out within a breath hold, it is still challenging for many sick patients. Compressed sensing (CS) is a viable alternative to accelerate this approach. However, undersampled images with identical sampling ratios differ from one another. Twenty subjects (n = 10 healthy and n = 10 patients with asthma) were scanned using a GE MR750 3 T scanner, acquiring fully sampled 2D multi-slice HP 129 Xe lung ventilation images (10 s breath hold, 128 × 80 (FE × PE-frequency encoding × phase encoding) and 16 slices). Using fully sampled data, 500 variable-density Cartesian random undersampling patterns were generated, each at eight different sampling ratios from 10% to 80%. The parallel imaging and compressed sensing (PICS) command from BART was employed to reconstruct undersampled data. The signal to noise ratio (SNR), structural similarity index measurement (SSIM) and sidelobe to peak ratio of each were subsequently compared. There was a high degree of variation in both SNR and SSIM results from each of the 500 masks of each sampling rate. As the undersampling increases, there is more variation in the quantifying metrics, for both healthy and asthmatic individuals. Our study shows that random undersampling poses a significant challenge when applied at sampling ratios less than 60%, despite fulfilling CS's incoherency criteria. Such low sampling ratios will result in a large variety of undersampling patterns. Therefore, skipped segments of k-space cannot be allowed to happen randomly at low sampling rates. By optimizing the sampling pattern, CS will reach its full potential and be able to be applied to a highly undersampled 129 Xe lung dataset., (© 2024 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

The Henry constants upon the adsorption of inert gases with a natural isotopic composition (argon, krypton, and xenon) on activated carbon of the AG-3, VSK-5, SKT-3, and NWC 12x40 brands in a temperature range of 15–80°C are determined. A positive correlation of the Henry constants with the specific surface and micropore volume and surface normalized to the unit volume of the solid phase is found. The parameters of the temperature dependence of the Henry constants are determined, and the isosteric heats of adsorption of inert gases are calculated. The experimental results are used for calculating the steady-state mode of operation of the radiochromatographic column of the radioactive-gas purification system of nuclear power plants. It is shown that, out of all the studied brands, the highest decontamination factors of the air flow from inert radioactive gases are provided by coconut shell carbons of the VSK-5 and NWC 12x40 brands, which are noticeably superior to the peat carbon activated with sulfuric acid and potassium hydroxide of the SKT-3 brand (currently applied at most Russian NPPs) with respect to this indicator. Carbon of the AG-3 does not make it possible to reach the required degree of purification. [ABSTRACT FROM AUTHOR]

We report absolutely calibrated isotropic Raman lineshapes for Kr2 and Xe2 and for KrXe at 294.5 K and compare them to quantum-mechanically generated lineshapes by using state-of-the-art second-order Møller-Plesset and DFT/B3LYP data sets for the induced mean dipole polarizability a. A very good agreement between the numerical and the experimental data was observed but the large uncertainty margins and the short Raman frequency interval probed in our experiment prevented us from rating on a more refined scale the performance of the tested a models. These drawbacks are inherent in isotropic Raman spectrum measurements and amplified for dissimilar pairs because, for such systems and spectra, the unreliable operation of subtracting optical signals of comparable magnitude occurs twice per Raman frequency shift value, thus penalizing twice the quality of the measured data. In light of our findings and of previously reported evidence about related electric properties in Kr2 and Xe2 and in KrXe, we are left with no doubt as to the consistency of the induced-polarizability and interatomic-potential data used for these three systems at the reported level of accuracy. [ABSTRACT FROM AUTHOR]

We report absolutely calibrated isotropic Raman lineshapes for Kr2 and Xe2 and for KrXe at 294.5 K and compare them to quantum-mechanically generated lineshapes by using state-of-the-art second-order Møller-Plesset and DFT/B3LYP data sets for the induced mean dipole polarizability a. A very good agreement between the numerical and the experimental data was observed but the large uncertainty margins and the short Raman frequency interval probed in our experiment prevented us from rating on a more refined scale the performance of the tested a models. These drawbacks are inherent in isotropic Raman spectrum measurements and amplified for dissimilar pairs because, for such systems and spectra, the unreliable operation of subtracting optical signals of comparable magnitude occurs twice per Raman frequency shift value, thus penalizing twice the quality of the measured data. In light of our findings and of previously reported evidence about related electric properties in Kr2 and Xe2 and in KrXe, we are left with no doubt as to the consistency of the induced-polarizability and interatomic-potential data used for these three systems at the reported level of accuracy. [ABSTRACT FROM AUTHOR]

Isotopic ratios of radioactive xenons sampled in the subsurface and atmosphere can be used to detect underground nuclear explosions (UNEs) and civilian nuclear reactors. Disparities in the half-lives of the radioactive decay chains are principally responsible for time-dependent concentrations of xenon isotopes. Contrasting timescales, combined with modern detection capabilities, make the xenon isotopic family a desirable surrogate for UNE detection. However, without including the physical details of post-detonation cavity changes that affect radioxenon evolution and subsurface transport, a UNE is treated as an idealized system that is both closed and well mixed for estimating xenon isotopic ratios and their correlations so that the spatially dependent behavior of xenon production, cavity leakage, and transport are overlooked. In this paper, we developed a multi-compartment model with radioactive decay and interactions between compartments. The model does not require the detailed domain geometry and parameterization that is normally needed by high-fidelity computer simulations, but can represent nuclide evolution within a compartment and migration among compartments under certain conditions. The closed-form solution to all nuclides in the series 131–136 is derived using analytical singular-value decomposition. The solution is further used to express xenon ratios as functions of time and compartment position. [ABSTRACT FROM AUTHOR]

Numerous algorithms have been developed to determine the source characteristics for an atmospheric radionuclide release, e.g., (Bieringer et al., 2017). This study compares three models that have been applied to the data collected by the International Monitoring System operated by the Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission to estimate source event parameters. Each model uses a different approach to estimate the parameters. A deterministic model uses a possible source region (PSR) approach (Ringbom et al., 2014) that is based on the correlation between predicted and measured sample values. A model (now called BAYEST) developed at Pacific Northwest National Laboratory uses a Bayesian formulation (Eslinger et al., 2019, 2020; Eslinger and Schrom, 2016). The FREAR model uses a different Bayesian formulation (De Meutter and Hoffman, 2020; De Meutter et al., 2021a, 2021b). The performance of the three source-location models is evaluated with 100 synthetic release cases for the single xenon isotope, 133Xe. The release cases resulted in detections in a fictitious network with 120 noble gas samplers. All three source-location models use the same sampling data. The two Bayesian models yield more accurate location estimates than the deterministic PSR model, with FREAR having slightly better location performance than BAYEST. Samplers with collection periods of 3, 6, 8, 12, and 24-h were used. Results from BAYEST show that location accuracy improves with each reduction in sample collection length. The BAYEST model is slightly better for estimating the start time of the release. The PSR model has about the same spread in start times as the FREAR model, but the PSR results have a better average start time. The Bayesian source-location algorithms give more accurate results than the PSR approach, and provide release magnitude estimates, while the base PSR model does not estimate the release magnitude. This investigation demonstrates that a reasonably dense sampling grid will sometimes yield poor location and time estimates regardless of the model. The poor estimates generally coincide with cases where there is a much larger distance between the release point and the first detecting sampler than the average sampler spacing. • Compare performance of three source-location algorithms using synthetic atmospheric samples. • Two Bayesian source-location models have quite similar results. • The Bayesian models give more accurate location estimates than a deterministic probable source region model. • Even a reasonably dense sampling grid sometimes yields poor location and release time estimates. • Shorter sample collection periods provide better location accuracy than longer periods. [ABSTRACT FROM AUTHOR]

Background: Individuals with asthma can vary widely in clinical presentation, severity, and pathobiology. Hyperpolarized xenon-129 (Xe129) MRI is a novel imaging method to provide 3-D mapping of both ventilation and gas exchange in the human lung., Purpose: To evaluate the functional changes in adults with asthma as compared to healthy controls using Xe129 MRI., Methods: All subjects (20 controls and 20 asthmatics) underwent lung function measurements and Xe129 MRI on the same day. Outcome measures included the pulmonary ventilation defect and transfer of inspired Xe129 into two soluble compartments: tissue and blood. Ten asthmatics underwent Xe129 MRI before and after bronchodilator to test whether gas transfer measures change with bronchodilator effects., Results: Initial analysis of the results revealed striking differences in gas transfer measures based on age, hence we compared outcomes in younger (n = 24, ≤ 35 years) versus older (n = 16, > 45 years) asthmatics and controls. The younger asthmatics exhibited significantly lower Xe129 gas uptake by lung tissue (Asthmatic: 0.98% ± 0.24%, Control: 1.17% ± 0.12%, P = 0.035), and higher Xe129 gas transfer from tissue to the blood (Asthmatic: 0.40 ± 0.10, Control: 0.31% ± 0.03%, P = 0.035) than the younger controls. No significant difference in Xe129 gas transfer was observed in the older group between asthmatics and controls (P > 0.05). No significant change in Xe129 transfer was observed before and after bronchodilator treatment., Conclusions: By using Xe129 MRI, we discovered heterogeneous alterations of gas transfer that have associations with age. This finding suggests a heretofore unrecognized physiological derangement in the gas/tissue/blood interface in young adults with asthma that deserves further study., (© 2024 American Association of Physicists in Medicine.)

The respiratory consequences of acute COVID-19 infection and related symptoms tend to resolve 4 weeks post-infection. However, for some patients, new, recurrent, or persisting symptoms remain beyond the acute phase and persist for months, post-infection. The symptoms that remain have been referred to as long-COVID. A number of research sites employed 129 Xe magnetic resonance imaging (MRI) during the pandemic and evaluated patients post-infection, months after hospitalization or home-based care as a way to better understand the consequences of infection on 129 Xe MR gas-exchange and ventilation imaging. A systematic review and comprehensive search were employed using MEDLINE via PubMed (April 2023) using the National Library of Medicine's Medical Subject Headings and key words: post-COVID-19, MRI, 129 Xe, long-COVID, COVID pneumonia, and post-acute COVID-19 syndrome. Fifteen peer-reviewed manuscripts were identified including four editorials, a single letter to the editor, one review article, and nine original research manuscripts (2020-2023). MRI and MR spectroscopy results are summarized from these prospective, controlled studies, which involved small sample sizes ranging from 9 to 76 participants. Key findings included: 1) 129 Xe MRI gas-exchange and ventilation abnormalities, 3 months post-COVID-19 infection, and 2) a combination of MRI gas-exchange and ventilation abnormalities alongside persistent symptoms in patients hospitalized and not hospitalized for COVID-19, 1-year post-infection. The persistence of respiratory symptoms and 129 Xe MRI abnormalities in the context of normal or nearly normal pulmonary function test results and chest computed tomography (CT) was consistent. Longitudinal improvements were observed in long-term follow-up of long-COVID patients but mean 129 Xe gas-exchange, ventilation heterogeneity values and symptoms remained abnormal, 1-year post-infection. Pulmonary functional MRI using inhaled hyperpolarized 129 Xe gas has played a role in detecting gas-exchange and ventilation abnormalities providing complementary information that may help develop our understanding of the root causes of long-COVID. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 5., (© 2023 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Rationale and Objectives: The current clinical standard for functional imaging of patients with lung ailments is nuclear medicine scintigraphy and Single Photon Emission Computed Tomography (SPECT) which detect the gamma decay of inhaled radioactive tracers. Hyperpolarized (HP) Xenon-129 MRI (XeMRI) of the lungs has recently been FDA approved and provides similar functional images of the lungs with higher spatial resolution than scintigraphy and SPECT. Here we compare Technetium-99m ( 99m Tc) diethylene-triamine-pentaacetate scintigraphy and SPECT with HP XeMRI in healthy controls, asthma, and chronic obstructive pulmonary disorder (COPD) patients., Materials and Methods: 59 subjects, healthy, with asthma, and with COPD, underwent 99m Tc scintigraphy/SPECT, standard spirometry, and HP XeMRI. XeMRI and SPECT images were registered for direct voxel-wise signal comparisons. Images were also compared using ventilation defect percentage (VDP), and a standard 6-compartment method. VDP calculated from XeMRI and SPECT images was compared to spirometry., Results: Median Pearson correlation coefficient for voxel-wise signal comparison was 0.698 (0.613-0.782) between scintigraphy and XeMRI and 0.398 (0.286-0.502) between SPECT and XeMRI. Correlation between VDP measures was r = 0.853, p < 0.05. VDP separated asthma and COPD from the control group and was significantly correlated with FEV1, FEV1/FVC, and FEF 25-75., Conclusion: HP XeMRI provides equivalent information to 99m Tc SPECT and standard spirometry measures. Additionally, XeMRI is non-invasive, hence it could be used for longitudinal studies for evaluating emerging treatment for lung ailments., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Talissa Altes reports a relationship with Polarean that includes: consulting or advisory. Talissa Altes reports a relationship with Philips that includes: speaking and lecture fees. John P. Mugler III, Jamie Mata, and Talissa Altes have patent System and Method for Improved Detection and Assessment of Changes in Lung-Tissue Structure issued to UNIVERSITY OF VIRGINA PATENT FOUNDATION., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Purpose: This study aimed to determine the association between functional impairment in small airways and symptoms of dyspnea in patients with Long-coronavirus disease (COVID), using imaging and computational modeling analysis., Patients and Methods: Thirty-four patients with Long-COVID underwent thoracic computed tomography and hyperpolarized Xenon-129 magnetic resonance imaging (HP Xe MRI) scans. Twenty-two answered dyspnea-12 questionnaires. We used a computed tomography-based full-scale airway network (FAN) flow model to simulate pulmonary ventilation. The ventilation distribution projected on a coronal plane and the percentage lobar ventilation modeled in the FAN model were compared with the HP Xe MRI data. To assess the ventilation heterogeneity in small airways, we calculated the fractal dimensions of the impaired ventilation regions in the HP Xe MRI and FAN models., Results: The ventilation distribution projected on a coronal plane showed an excellent resemblance between HP Xe MRI scans and FAN models (structure similarity index: 0.87 ± 0.04). In both the image and the model, the existence of large clustered ventilation defects was not identifiable regardless of dyspnea severity. The percentage lobar ventilation of the HP Xe MRI and FAN model showed a strong correlation (ρ = 0.63, P < 0.001). The difference in the fractal dimension of impaired ventilation zones between the low and high dyspnea-12 score groups was significant (HP Xe MRI: 1.97 [1.89 to 2.04] and 2.08 [2.06 to 2.14], P = 0.005; FAN: 2.60 [2.59 to 2.64] and 2.64 [2.63 to 2.65], P = 0.056)., Conclusions: This study has identified a potential association of small airway functional impairment with breathlessness in Long-COVID, using fractal analysis of HP Xe MRI scans and FAN models., Competing Interests: J.H. has received the National Research Foundation of Korea grant funded by the Korean government (#NRF-2019R1I1A1A01063383). The remaining authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Fully quantum-mechanical treatment of the effects of thermal rovibrational motion in a heavy-element molecule with relativistic effects is carried out for the heavy 129/131Xe and light 19F nuclear shieldings in the linear XeF2 molecule. More importantly, purely quantum-mechanical, intramolecular phenomena, the primary and secondary isotope effect on these shieldings, respectively, are treated with including both the zero-point vibrational and finite-temperature effects. While large solvent effects influence the experimental absolute shielding constants and chemical shifts (thereby making comparison of experiment and theory very difficult), they are not significant for the isotope shifts. We study the role of electron correlation at both nonrelativistic (NR) and relativistic [Breit-Pauli perturbational theory (BPPT) as well as 4-component Dirac theory] level. We obtain quantitative agreement with the nearly solvent-independent experimental 19F secondary isotope shifts. This implies a promising accuracy for our predictions of the experimentally so far non-existing primary Xe isotope shift and the temperature dependence of Xe and F chemical shifts corresponding to a low pressure gas phase. To achieve this, a combination of high-level ab initio NR shielding surface is found necessary, in the present work supplemented by relativistic corrections by density-functional theory (DFT). Large errors are demonstrated to arise due to DFT in the NR shielding surface, explaining findings in recent computational studies of heavy-element isotope shifts. Besides a high-quality property hypersurface, the inclusion of thermal effects (in addition to zero-point motion) is also necessary to compare with experimental results. The geometry dependence of the different relativistic influences on the wave function, Zeeman interaction, and hyperfine interaction, as well as their role in the temperature dependence of both the Xe and F shielding constants and their isotope shifts, are discussed. The relativistic rovibrational effects arise from the same individual contributions as previously found for the chemical shifts and shielding anisotropies. In general, the spin-orbit interactions are more sensitive to rovibrational motion than the scalar relativistic contributions. A previously suggested third-order BPPT contribution to shielding anisotropy is shown to be important for a better agreement with experiment. [ABSTRACT FROM AUTHOR]

We demonstrate a new way of investigating the processing of the lunar surface (and other planetary regoliths) that combines Xe S -Xe N ages (based on uranium fission) in individual zircons with their xenon isotopic record of solar wind and cosmic ray exposure. We report the first xenon isotopic analyses of individual lunar zircons (from Apollo 14 soil and breccias samples). Parallel analyses of a suite of zircons from the Vredefort impact structure in South Africa revealed Xe S -Xe N ages that agree well with U-Pb systematics, suggesting that the diffusion kinetics of xenon and lead in zircon are similar in the pressure-temperature environment of sub-basin floors. In contrast, all Apollo 14 zircons examined exhibit Xe S -Xe N ages markedly younger than the associated U-Pb and 207Pb-206Pb ages, and soil zircons with 207Pb-206Pb ages greater than 3900 Ma produced an abundance of Xe S -Xe N ages <1000 Ma. The young ages cannot be explained by thermal neutron irradiation on the lunar surface, and diurnal heating is unlikely to cause preferential loss of xenon. As such these young soil zircon ages likely record regolith gardening processes. The breccia zircons typically record older ages, >2400 Ma, suggesting that these samples may be useful for investigating ancient events and regolith processing at an earlier epoch. However, none of the zircons contain xenon from now-extinct 244Pu implying that either the samples have completely degassed since ∼3900 Ma or that the initial Pu/U ratio of the Moon is lower than that on Earth. We also describe a methodology for conducting component deconvolution that can be applied to multi-isotopes systems beyond xenon. We have also determined new xenon isotopic yields from rare earth element spallation in the lunar environment and high precision yields for neutron induced fission of 235U in geologic samples. [ABSTRACT FROM AUTHOR]

An extended microscopic version of the interacting-boson model is developed. The properties of yrast-band states in even cerium isotopes up to the spin–parity of are calculated on the basis of this model. These spin values include those at which band crossing occurs. The model parameters are calculated on the basis of employing an average spherical potential and residual multipole forces. An extension of the model is accomplished via taking into account high-spin quasiparticle pairs, whereby a satisfactory description of energies and values was obtained without introducing effective charges. The present investigation is a continuation of a similar analysis of the properties of low-lying collective states in even xenon and barium isotopes. [ABSTRACT FROM AUTHOR]

The current composition of giant planet atmospheres provides information on how such planets formed, and on the origin of the solid building blocks that contributed to their formation. Noble gas abundances and their isotope ratios are among the most valuable pieces of evidence for tracing the origin of the materials from which the giant planets formed. In this review we first outline the current state of knowledge for heavy element abundances in the giant planets and explain what is currently understood about the reservoirs of icy building blocks that could have contributed to the formation of the Ice Giants. We then outline how noble gas isotope ratios have provided details on the original sources of noble gases in various materials throughout the solar system. We follow this with a discussion on how noble gases are trapped in ice and rock that later became the building blocks for the giant planets and how the heavy element abundances could have been locally enriched in the protosolar nebula. We then provide a review of the current state of knowledge of noble gas abundances and isotope ratios in various solar system reservoirs, and discuss measurements needed to understand the origin of the ice giants. Finally, we outline how formation and interior evolution will influence the noble gas abundances and isotope ratios observed in the ice giants today. Measurements that a future atmospheric probe will need to make include (1) the 3He/4He isotope ratio to help constrain the protosolar D/H and 3He/4He; (2) the 20Ne/22Ne and 21Ne/22Ne to separate primordial noble gas reservoirs similar to the approach used in studying meteorites; (3) the Kr/Ar and Xe/Ar to determine if the building blocks were Jupiter-like or similar to 67P/C-G and Chondrites; (4) the krypton isotope ratios for the first giant planet observations of these isotopes; and (5) the xenon isotopes for comparison with the wide range of values represented by solar system reservoirs. [ABSTRACT FROM AUTHOR]

For the first time, abundances of the main xenon components (Xe-P3, Xe-P3(fr), Xe-P6 and Xe-pr instead Xe-HL) in the nanodiamonds of Orgueil (CI), Tieschitz (H3.6) and Indarch (EH3-4) meteorites have been calculated. The Xe-pr component is the excess fraction of xenon isotopes in the Xe-HL component relative to Xe-P3 (fr) and mainly consists of the 124, 126, 134, 136Хе isotopes formed in p- and r-processes of nucleosynthesis in a type II supernova explosion. Analysis of the data has shown the following. (1) The main nanodiamond component of Xe is Xe-P3 (fr), and its maximum during pyrolysis, like Xe-pr and Xe-P6, is high-temperature (>1000°C), irrespectively of the petrological type of meteorites. (2) The relative abundance of the Xe-pr component in the nanodiamonds of Indarch meteorite, which is most enriched in anomalous xenon components, is about 15% of the total xenon abundance in the diamond of this meteorite, which is significantly lower than the abundance of the Xe-HL component – about 87%. (3) The xenon components are contained in the individual populations of the diamond grains with different thermo-oxidative stability. The data we obtained and in (Huss, Lewis, 1994b) on the abundances and the yield kinetics of xenon components in meteoritic nanodiamonds, based on the Xe-pr and Xe-HL isotope compositions, respectively, most likely show their limiting values. Тhe real properties of xenon components are assumed to be similar to those obtained when using Xe-pr component for calculations, taking into account the data on the carbon isotope composition in the nanodiamond grains of the Allende meteorite (Lewis et al., 2019). [ABSTRACT FROM AUTHOR]