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Search Results (285)

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19 pages, 950 KiB  
Review
A Narrative Review of Theranostics in Neuro-Oncology: Advancing Brain Tumor Diagnosis and Treatment Through Nuclear Medicine and Artificial Intelligence
by Rafail C. Christodoulou, Platon S. Papageorgiou, Rafael Pitsillos, Amanda Woodward, Sokratis G. Papageorgiou, Elena E. Solomou and Michalis F. Georgiou
Int. J. Mol. Sci. 2025, 26(15), 7396; https://doi.org/10.3390/ijms26157396 (registering DOI) - 31 Jul 2025
Abstract
This narrative review explores the integration of theranostics and artificial intelligence (AI) in neuro-oncology, addressing the urgent need for improved diagnostic and treatment strategies for brain tumors, including gliomas, meningiomas, and pediatric central nervous system neoplasms. A comprehensive literature search was conducted through [...] Read more.
This narrative review explores the integration of theranostics and artificial intelligence (AI) in neuro-oncology, addressing the urgent need for improved diagnostic and treatment strategies for brain tumors, including gliomas, meningiomas, and pediatric central nervous system neoplasms. A comprehensive literature search was conducted through PubMed, Scopus, and Embase for articles published between January 2020 and May 2025, focusing on recent clinical and preclinical advancements in personalized neuro-oncology. The review synthesizes evidence on novel theranostic agents—such as Lu-177-based radiopharmaceuticals, CXCR4-targeted PET tracers, and multifunctional nanoparticles—and highlights the role of AI in enhancing tumor detection, segmentation, and treatment planning through advanced imaging analysis, radiogenomics, and predictive modeling. Key findings include the emergence of nanotheranostics for targeted drug delivery and real-time monitoring, the application of AI-driven algorithms for improved image interpretation and therapy guidance, and the identification of current limitations such as data standardization, regulatory challenges, and limited multicenter validation. The review concludes that the convergence of AI and theranostic technologies holds significant promise for advancing precision medicine in neuro-oncology, but emphasizes the need for collaborative, multidisciplinary research to overcome existing barriers and enable widespread clinical adoption. Full article
(This article belongs to the Special Issue Biomarker Discovery and Validation for Precision Oncology)
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11 pages, 711 KiB  
Article
Cadmium Accumulation and Regulation in the Freshwater Mussel Anodonta woodiana
by Xiubao Chen, Chao Song, Jiazhen Jiang, Tao Jiang, Junren Xue, Ibrahim Bah, Mengying Gu, Meiyi Wang and Shunlong Meng
Toxics 2025, 13(8), 646; https://doi.org/10.3390/toxics13080646 - 30 Jul 2025
Abstract
Cadmium (Cd) pollution poses a serious threat to freshwater ecosystems. The freshwater mussel Anodonta woodiana is increasingly used as a bioindicator for monitoring Cd pollution in aquatic environments. However, the primary routes of Cd accumulation in A. woodiana remain unclear, and the molecular [...] Read more.
Cadmium (Cd) pollution poses a serious threat to freshwater ecosystems. The freshwater mussel Anodonta woodiana is increasingly used as a bioindicator for monitoring Cd pollution in aquatic environments. However, the primary routes of Cd accumulation in A. woodiana remain unclear, and the molecular regulatory mechanisms underlying Cd accumulation are poorly understood. To address these gaps, this study employed a novel stable isotope dual-tracer technique to trace Cd from water (waterborne 112Cd) and the green alga Chlorella vulgaris (dietary 113Cd) during the simultaneous exposure experiment. Comparative transcriptomic analysis was then conducted to characterize molecular responses in A. woodiana following Cd exposure. The results showed that although newly accumulated 112Cd and 113Cd increased with exposure concentration and duration, the relative importance of 112Cd (91.6 ± 2.8%) was significantly higher than that of 113Cd (8.4 ± 2.8%) (p < 0.05). Cd exposure induced differentially expressed genes primarily enriched in the metabolic processes, cellular processes, and/or the ubiquitin-mediated proteolysis pathway. Within the ubiquitin-mediated proteolysis pathway, TRIP12 (E3 ubiquitin-protein ligase TRIP12) and Cul5 (cullin-5) were significantly upregulated. The findings will provide critical insights for interpreting Cd biomonitoring data in freshwater environments using mussels as bioindicators. Full article
(This article belongs to the Special Issue The Impact of Heavy Metals on Aquatic Ecosystems)
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16 pages, 4204 KiB  
Article
Assessment of the Source and Dynamics of Water Inrush Based on Hydrochemical Mixing Model in Zhaxikang Mining Area, Tibet, China
by Hongyu Gu, Yujie Liu, Huizhong Liu, Xinyu Cen, Jinxian Zhong, Dewei Wang and Lei Yi
Water 2025, 17(15), 2201; https://doi.org/10.3390/w17152201 - 23 Jul 2025
Viewed by 218
Abstract
Water source identification and dynamic assessment are critical for mining safety, particularly in mines governed by complex geological structures. The hydrochemical mixing model demonstrates a natural advantage for early warning of water intrusion compared to geophysical monitoring techniques. This study discusses core issues [...] Read more.
Water source identification and dynamic assessment are critical for mining safety, particularly in mines governed by complex geological structures. The hydrochemical mixing model demonstrates a natural advantage for early warning of water intrusion compared to geophysical monitoring techniques. This study discusses core issues related to the mixing model, including the conceptual framework, selection of end-members, and choice of tracers, and formulates principles for general applicability. In this study, three sources were identified using the conceptual model and hydrochemical analysis: water in F7 (main fault), shallow fracture water, and river water. A correlation analysis and variability analysis were applied to determine the tracers, and the 18O, D, Cl, B, and Li were determined. The end-members of the three sources are time-dependent in July and September, especially the shallow fracture water’s end-members. The dynamics of the mixing ratios of the three sources suggest that river water contributes only to the inrush (1–4%), with this being especially low in September, as the increasing hydraulic gradient from south to north prevents recharge. The water in F7 accounts for at least 70% of the inrush water. Shallow fracture water accounts for the rest and increases slightly in September as the precipitation increases in mining-disturbed areas. Finally, this work makes the later water control work more targeted. Full article
(This article belongs to the Section Hydrogeology)
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20 pages, 2336 KiB  
Article
Microbial DNA-Based Monitoring of Underground Crude Oil Storage Bases Using Water-Sealed Rock-Cavern Tanks
by Ayae Goto, Shunichi Watanabe, Katsumasa Uruma, Yuki Momoi, Takuji Oomukai and Hajime Kobayashi
Water 2025, 17(15), 2197; https://doi.org/10.3390/w17152197 - 23 Jul 2025
Viewed by 240
Abstract
Strategic petroleum reserves are critical for energy security. In Japan, 0.5 million kiloliters of crude oil (12% of the state-owned reserves) is stored using underground rock-cavern tanks, which comprise unlined horizontal tunnels bored into bedrock. Crude oil is held within the tank by [...] Read more.
Strategic petroleum reserves are critical for energy security. In Japan, 0.5 million kiloliters of crude oil (12% of the state-owned reserves) is stored using underground rock-cavern tanks, which comprise unlined horizontal tunnels bored into bedrock. Crude oil is held within the tank by water inside the tank, the pressure of which is kept higher than that of the crude oil by natural groundwater and irrigation water. This study applied microbial DNA-based monitoring to assess the water environments in and around national petroleum-stockpiling bases (the Kuji, Kikuma, and Kushikino bases) using the rock-cavern tanks. Forty-five water samples were collected from the rock-cavern tanks, water-supply tunnels, and observation wells. Principal-component analysis and hierarchical clustering indicated that microbial profiles of the water samples reflect the local environments of their origins. Particularly, the microbial profiles of water inside the rock-cavern tanks were distinct from other samples, revealing biological conditions and hence environmental characteristics within the tanks. Moreover, the clustering analysis indicated distinct features of water samples that have not been detected by other monitoring methods. Thus, microbial DNA-based monitoring provides valuable information on the in situ environments of rock-cavern tanks and can serve as an extremely sensitive measurement to monitor the underground oil storage. Full article
(This article belongs to the Section Hydrogeology)
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21 pages, 1682 KiB  
Article
Dynamic Multi-Path Airflow Analysis and Dispersion Coefficient Correction for Enhanced Air Leakage Detection in Complex Mine Ventilation Systems
by Yadong Wang, Shuliang Jia, Mingze Guo, Yan Zhang and Yongjun Wang
Processes 2025, 13(7), 2214; https://doi.org/10.3390/pr13072214 - 10 Jul 2025
Viewed by 365
Abstract
Mine ventilation systems are critical for ensuring operational safety, yet air leakage remains a pervasive challenge, leading to energy inefficiency and heightened safety risks. Traditional tracer gas methods, while effective in simple networks, exhibit significant errors in complex multi-entry systems due to static [...] Read more.
Mine ventilation systems are critical for ensuring operational safety, yet air leakage remains a pervasive challenge, leading to energy inefficiency and heightened safety risks. Traditional tracer gas methods, while effective in simple networks, exhibit significant errors in complex multi-entry systems due to static empirical parameters and environmental interference. This study proposes an integrated methodology that combines multi-path airflow analysis with dynamic longitudinal dispersion coefficient correction to enhance the accuracy of air leakage detection. Utilizing sulfur hexafluoride (SF6) as the tracer gas, a phased release protocol with temporal isolation was implemented across five strategic points in a coal mine ventilation network. High-precision detectors (Bruel & Kiaer 1302) and the MIVENA system enabled synchronized data acquisition and 3D network modeling. Theoretical models were dynamically calibrated using field-measured airflow velocities and dispersion coefficients. The results revealed three deviation patterns between simulated and measured tracer peaks: Class A deviation showed 98.5% alignment in single-path scenarios, Class B deviation highlighted localized velocity anomalies from Venturi effects, and Class C deviation identified recirculation vortices due to abrupt cross-sectional changes. Simulation accuracy improved from 70% to over 95% after introducing wind speed and dispersion adjustment coefficients, resolving concealed leakage pathways between critical nodes and key nodes. The study demonstrates that the dynamic correction of dispersion coefficients and multi-path decomposition effectively mitigates errors caused by turbulence and geometric irregularities. This approach provides a robust framework for optimizing ventilation systems, reducing invalid airflow losses, and advancing intelligent ventilation management through real-time monitoring integration. Full article
(This article belongs to the Section Process Control and Monitoring)
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18 pages, 1117 KiB  
Review
Surgical Management of Mediastinal Ectopic Parathyroids
by Giacomo Rabazzi, Gianmarco Elia, Vittorio Aprile, Stylianos Korasidis, Maria Giovanna Mastromarino, Diana Bacchin, Alessandra Lenzini, Marcello Carlo Ambrogi, Greta Alì, Filomena Cetani, Gabriele Materazzi and Marco Lucchi
J. Pers. Med. 2025, 15(7), 276; https://doi.org/10.3390/jpm15070276 - 30 Jun 2025
Viewed by 495
Abstract
Primary hyperparathyroidism is commonly caused by parathyroid adenomas, hyperplasia, or, rarely, carcinoma. In up to 20% of cases, parathyroid tissue may be ectopic, often located in the mediastinum due to aberrant embryologic migration. Ectopic parathyroid glands pose a diagnostic and therapeutic challenge, and [...] Read more.
Primary hyperparathyroidism is commonly caused by parathyroid adenomas, hyperplasia, or, rarely, carcinoma. In up to 20% of cases, parathyroid tissue may be ectopic, often located in the mediastinum due to aberrant embryologic migration. Ectopic parathyroid glands pose a diagnostic and therapeutic challenge, and an accurate preoperative localization is essential for an effective and safe resection. Imaging modalities such as CT scan, TC-sestamibi scintigraphy, PET/CT, ultrasonography and MRI are routinely employed, whereas combined techniques offer improved diagnostic accuracy. Emerging approaches, however, including PET/CT with choline tracers, have shown promise in enhancing sensitivity in complex or recurrent cases. When ectopic glands are in the mediastinum, thoracic surgical intervention is required. Traditional open approaches, such as sternotomy or thoracotomy, are associated with significant morbidity. The development and evolution of minimally invasive surgery (MIS) has become the preferred approach in selected cases. When MIS is performed, intraoperative assessment and parathyroid identification are crucial to ensure complete gland removal. Intraoperative parathyroid hormone (ioPTH) monitoring provides real-time confirmation of surgical success. The integration of advanced imaging, intraoperative monitoring, and minimally invasive techniques significantly improves surgical outcomes while minimizing complications and accelerating patient recovery. Ultimately, the effective treatment of ectopic parathyroid glands relies on a personalized approach, adapting both diagnostic and surgical strategies to the unique anatomical and clinical context of each patient. Integration of advanced imaging, intraoperative monitoring, and minimally invasive techniques, combined with a multidisciplinary team involving endocrinologists, radiologists, and thoracic surgeons, is key to optimizing outcomes and reducing patient morbidity. Full article
(This article belongs to the Section Methodology, Drug and Device Discovery)
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15 pages, 294 KiB  
Review
The Role of [18F]FDG PET Imaging for the Assessment of Pulmonary Lymphangitic Carcinomatosis: A Comprehensive Narrative Literature Review
by Francesco Dondi, Pietro Bellini, Michela Cossandi, Luca Camoni, Roberto Rinaldi, Gian Luca Viganò and Francesco Bertagna
Diagnostics 2025, 15(13), 1626; https://doi.org/10.3390/diagnostics15131626 - 26 Jun 2025
Viewed by 423
Abstract
Background/Objectives: Pulmonary lymphangitic carcinomatosis (PLC) is a rare, aggressive manifestation of metastatic cancer characterized by lymphatic infiltration of the lungs, typically indicating advanced disease and poor prognosis. Methods: This comprehensive narrative review evaluates the role of [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography [...] Read more.
Background/Objectives: Pulmonary lymphangitic carcinomatosis (PLC) is a rare, aggressive manifestation of metastatic cancer characterized by lymphatic infiltration of the lungs, typically indicating advanced disease and poor prognosis. Methods: This comprehensive narrative review evaluates the role of [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) imaging in assessing PLC. Results: Current evidence demonstrates that [18F]FDG PET/CT achieves high diagnostic accuracy, with sensitivity and specificity ranging from 86 to 97% and 84 to 100%, respectively, particularly when employing semiquantitative metrics such as peritumoral standardized uptake value (SUVmax) thresholds (e.g., ≥2.1). PET/CT surpasses high-resolution computed tomography (HRCT) in distinguishing PLC from mimics like pulmonary sarcoidosis by identifying distinct metabolic patterns: bronchovascular hypermetabolism in PLC versus subpleural nodular uptake in sarcoidosis. Prognostically, metabolic tumor burden (e.g., SUVmax × involved lobes) and novel cPLC classifications (localized to the ipsilateral or contralateral lung) independently predict progression-free survival. However, challenges persist, including non-specific tracer uptake in inflammatory conditions and variability in SUV measurements due to technical factors. Emerging digital PET/CT systems, with enhanced spatial resolution, may improve the detection of focal PLC and reduce false negatives. While [18F]FDG PET/CT is invaluable for whole-body staging, therapeutic monitoring and biopsy guidance, the standardization of protocols and multicenter validation of prognostic models are critical for clinical integration. Future research should explore novel tracers (e.g., PSMA for prostate cancer-related PLC) and machine learning approaches to refine diagnostic and prognostic accuracy. Conclusions: This review underscores the role and the transformative potential of [18F]FDG PET/CT in PLC management while advocating for rigorous standardization to maximize its clinical utility. Full article
(This article belongs to the Special Issue Recent Advances in Radiomics in Medical Imaging)
18 pages, 5162 KiB  
Article
Cartilage-Specific 18F-NaF Uptake in Rat Models: A Multimodal In Vitro and Ex Vitro Comparative Study with 99mTc-MDP
by Qingxiao Li, Jianpeng Gao, Yiqun Wang, Yaoyao Song, Liwei Liu, Cong Zhang, Ming Li, Haodan Dang and Jiahe Tian
Biomedicines 2025, 13(7), 1540; https://doi.org/10.3390/biomedicines13071540 - 24 Jun 2025
Viewed by 333
Abstract
Background: 18F-NaF and 99mTc-MDP are widely used bone imaging tracers, but their comparative uptake in bone versus cartilage is unclear. This study aimed to directly compare these patterns in rats to guide musculoskeletal molecular imaging. Methods: Male Sprague-Dawley rats underwent [...] Read more.
Background: 18F-NaF and 99mTc-MDP are widely used bone imaging tracers, but their comparative uptake in bone versus cartilage is unclear. This study aimed to directly compare these patterns in rats to guide musculoskeletal molecular imaging. Methods: Male Sprague-Dawley rats underwent in vivo and ex vivo radiotracer studies. Tracer uptake (%ID/g) was quantified in bone and cartilage at 30, 60, or 120 min post-injection (18F-NaF or 99mTc-MDP), and across different ages. Additional rats received subcutaneous implants of viable or devitalized bone and cartilage; uptake was assessed using PET/CT, autoradiography, and histology. Results: 18F-NaF showed faster blood/background clearance and higher target-to-background ratios compared to 99mTc-MDP, especially in weight-bearing joint cartilage. 18F-NaF uptake in cancellous bone significantly exceeded that of 99mTc-MDP, whereas 99mTc-MDP showed higher uptake in knee cartilage. Age-related analysis showed maximal knee cartilage accumulation in aged rats. Histological and cell inactivation studies confirmed that 18F-NaF uptake reflects both cellular activity and degree of calcification. Conclusions:18F-NaF demonstrates distinctive, quantifiable uptake in cartilage, dependent on both cellular activity and calcification, and exhibits favorable imaging characteristics versus 99mTc-MDP for cartilage metabolism. These findings support 18F-NaF as a promising tool for early diagnosis and therapeutic monitoring of bone and joint disorders, and provide pathophysiological insight into the dynamics of the bone–cartilage interface. Full article
(This article belongs to the Section Biomedical Engineering and Materials)
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35 pages, 2244 KiB  
Review
Advances in Molecular Imaging of VEGFRs: Innovations in Imaging and Therapeutics
by Hanieh Karimi, Sarah Lee, Wenqi Xu, Sigrid A. Langhans, David K. Johnson, Erik Stauff, Heidi H. Kecskemethy, Lauren W. Averill and Xuyi Yue
Int. J. Mol. Sci. 2025, 26(11), 5373; https://doi.org/10.3390/ijms26115373 - 4 Jun 2025
Viewed by 825
Abstract
Vascular endothelial growth factor receptors (VEGFRs) are key regulators of angiogenesis, lymphangiogenesis, and vascular permeability, playing essential roles in both physiological and pathological processes. The VEGFR family, including VEGFR-1, VEGFR-2, and VEGFR-3, interacts with structurally related VEGF ligands (VEGFA, VEGFB, VEGFC, VEGFD, and [...] Read more.
Vascular endothelial growth factor receptors (VEGFRs) are key regulators of angiogenesis, lymphangiogenesis, and vascular permeability, playing essential roles in both physiological and pathological processes. The VEGFR family, including VEGFR-1, VEGFR-2, and VEGFR-3, interacts with structurally related VEGF ligands (VEGFA, VEGFB, VEGFC, VEGFD, and placental growth factor [PlGF]), activating downstream signaling pathways that mediate critical cellular processes, including proliferation, migration, and survival. Dysregulation of VEGFR signaling has been implicated in numerous diseases, such as cancer, cardiovascular conditions, and inflammatory disorders. Targeting VEGFRs with radiopharmaceuticals, such as radiolabeled peptides, antibodies, and specific tracers like 64Cu-bevacizumab and 89Zr-ramucirumab, has emerged as a powerful strategy for non-invasive imaging of VEGFR expression and distribution in vivo. Through positron emission tomography (PET) and single-photon emission computed tomography (SPECT), these targeted tracers enable real-time visualization of angiogenic and lymphangiogenic activity, providing insights into disease progression and therapeutic responses. This review explores the current advances in VEGFR-targeted imaging, focusing on the development of novel tracers, radiolabeling techniques, and their in vivo imaging characteristics. We discuss the preclinical and clinical applications of VEGFR imaging, highlight existing challenges, and provide perspectives on future innovations that could further enhance precision diagnostics and therapeutic monitoring in angiogenesis and lymphangiogenesis-driven diseases. Full article
(This article belongs to the Special Issue Molecular Imaging for Cancer Theranostics)
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9 pages, 571 KiB  
Perspective
a-synuclein PET Imaging: From Clinical Utility in Multiple System Atrophy to the Possible Diagnosis of Parkinson’s Disease
by Francesca Capotosti
Cells 2025, 14(11), 834; https://doi.org/10.3390/cells14110834 - 3 Jun 2025
Viewed by 965
Abstract
The development of PET tracers for the detection of pathological alpha-synuclein (a-synuclein) has the potential to revolutionize the diagnosis, monitoring, and therapeutic interventions of synucleinopathies, including Parkinson’s disease. The journey toward identifying effective PET imaging agents, however, has faced significant challenges due to [...] Read more.
The development of PET tracers for the detection of pathological alpha-synuclein (a-synuclein) has the potential to revolutionize the diagnosis, monitoring, and therapeutic interventions of synucleinopathies, including Parkinson’s disease. The journey toward identifying effective PET imaging agents, however, has faced significant challenges due to the complexity and heterogeneity of the a-synuclein structures. Achieving the goal is further compounded by the low density of the pathological target, necessitating that the tracer exhibits a high binding potential, as well as the co-existence of other protein aggregates, requiring the tracer to be highly specific and selective for a-synuclein. In this perspective article, the challenges regarding developing PET tracers for a-synuclein are explored and summarized, together with the most significant recent advances in the field. These include the approaches used by our laboratories, leading to the publication of the first clinical PET images of a-synuclein pathology in patients with multiple system atrophy (MSA). Building on the current understanding of the different a-synuclein species and findings based on the success of PET tracers in the field of neurodegenerative diseases, future directions are considered also to achieve the imaging of a-synuclein pathology in Parkinson’s patients. Full article
(This article belongs to the Special Issue Development of PET Radiotracers for Imaging Alpha-Synuclein)
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16 pages, 5053 KiB  
Article
A New Method for Determining Production Profiles Based on Intelligent Slow-Release Chemical Tracers
by Liang Wang, Lingang Lv and Peng Chen
Processes 2025, 13(6), 1705; https://doi.org/10.3390/pr13061705 - 29 May 2025
Viewed by 331
Abstract
With the development of tracer technology and the improvement of fine management in oil fields, chemical tracer monitoring is widely used to analyze the production profiles in commingled wells and horizontal wells. However, most existing tracer technologies can only determine the production profile [...] Read more.
With the development of tracer technology and the improvement of fine management in oil fields, chemical tracer monitoring is widely used to analyze the production profiles in commingled wells and horizontal wells. However, most existing tracer technologies can only determine the production profile and cannot calculate the water cut. This paper proposes an intelligent slow-release chemical tracer monitoring technology and a corresponding interpretation methodology, which can quantify the oil and water production rates and dynamically analyze the water cut of production profiles by simultaneous deployment of oil-soluble and water-soluble tracers. To validate this approach, this method was applied to well A of the Bohai Oilfield. The results showed that the calculation model based on produced tracer concentration can quantitatively determine the production profile and water cut of the monitored well. During the stable production period, Well A exhibited high production rates and a low water cut, and the contribution of oil production varied greatly among different layers. The first and third sections were identified as the main contributors, accounting for 51.8% and 23.2% of production, respectively, while the second and fourth sections showed lower contributions of 15.1% and 9.9%. The water cut of each section was below 30%. This intelligent slow-release tracer monitoring technology allowed for continuous production profiles in the monitored well. The proposed method provides effective guidance for characterizing the production profile and water flooding patterns of each layer. It is helpful for the efficient development of oil and gas reservoirs. Full article
(This article belongs to the Section Chemical Processes and Systems)
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19 pages, 4006 KiB  
Article
An Assessment of TROPESS CrIS and TROPOMI CO Retrievals and Their Synergies for the 2020 Western U.S. Wildfires
by Oscar A. Neyra-Nazarrett, Kazuyuki Miyazaki, Kevin W. Bowman and Pablo E. Saide
Remote Sens. 2025, 17(11), 1854; https://doi.org/10.3390/rs17111854 - 26 May 2025
Viewed by 514
Abstract
The 2020 wildfire season in the Western U.S. was historic in its intensity and impact on the land and atmosphere. This study aims to characterize satellite retrievals of carbon monoxide (CO), a tracer of combustion and signature of those fires, from two key [...] Read more.
The 2020 wildfire season in the Western U.S. was historic in its intensity and impact on the land and atmosphere. This study aims to characterize satellite retrievals of carbon monoxide (CO), a tracer of combustion and signature of those fires, from two key satellite instruments: the Cross-track Infrared Sounder (CrIS) and the Tropospheric Monitoring Instrument (TROPOMI). We evaluate them during this event and assess their synergies. These two retrievals are matched temporally, as the host satellites are in tandem orbit and spatially by aggregating TROPOMI to the CrIS resolution. Both instruments show that the Western U.S. displayed significantly higher daily average CO columns compared to the Central and Eastern U.S. during the wildfires. TROPOMI showed up to a factor of two larger daily averages than CrIS during the most intense fire period, likely due to differences in the vertical sensitivity of the two instruments and representative of near-surface CO abundance near the fires. On the other hand, there was excellent agreement between the instruments in downwind free tropospheric plumes (scatter plot slopes of 0.96–0.99), consistent with their vertical sensitivities and indicative of mostly lofted smoke. Temporally, TROPOMI CO column peaks were delayed relative to the Fire Radiative Power (FRP), and CrIS peaks were delayed with respect to TROPOMI, particularly during the intense initial weeks of September, suggesting boundary layer buildup and ventilation. Satellite retrievals were evaluated using ground-based CO column estimates from the Network for the Detection of Atmospheric Composition Change (NDACC) and the Total Carbon Column Observing Network (TCCON), showing Normalized Mean Errors (NMEs) for CrIS and TROPOMI below 32% and 24%, respectively, when compared to all stations studied. While Normalized Mean Bias (NMB) was typically low (absolute value below 15%), there were larger negative biases at Pasadena, likely associated with sharp spatial gradients due to topography and proximity to a large city, which is consistent with previous research. In situ CO profiles from AirCore showed an elevated smoke plume for 15 September 2020, highlighted consistency between TROPOMI and CrIS CO columns for lofted plumes. This study demonstrates that both CrIS and TROPOMI provide complementary information on CO distribution. CrIS’s sensitivity in the middle and lower free troposphere, coupled with TROPOMI’s effectiveness at capturing total columns, offers a more comprehensive view of CO distribution during the wildfires than either retrieval alone. By combining data from both satellites as a ratio, more detailed information about the vertical location of the plumes can potentially be extracted. This approach can enhance air quality models, improve vertical estimation accuracy, and establish a new method for assessing lower tropospheric CO concentrations during significant wildfire events. Full article
(This article belongs to the Section Atmospheric Remote Sensing)
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24 pages, 5378 KiB  
Article
Assessment of the Measured Mixing Time in a Water Model of Asymmetrical Gas-Stirred Ladle with a Low Gas Flowrate Part II: Effect of the Salt Solution Tracer Volume and Concentration
by Yansong Zhao, Xin Tao, Linbo Li, Zhijie Guo, Hongyu Qi, Jia Wang, Kun Yang, Wanming Lin, Jinping Fan and Chao Chen
Symmetry 2025, 17(5), 802; https://doi.org/10.3390/sym17050802 - 21 May 2025
Cited by 1 | Viewed by 522
Abstract
Mixing time, as a key parameter for evaluating ladle refining efficiency, has long attracted extensive attention from researchers. In typical experimental studies, salt solution tracers are introduced into ladle water models to assess the degree of mixing within the ladle. Previous studies have [...] Read more.
Mixing time, as a key parameter for evaluating ladle refining efficiency, has long attracted extensive attention from researchers. In typical experimental studies, salt solution tracers are introduced into ladle water models to assess the degree of mixing within the ladle. Previous studies have demonstrated that the volume of tracer can significantly influence the measured mixing time. However, the gas flow rates employed in these studies are generally relatively high, whereas, in industrial operations, especially during final composition adjustments, lower gas flow rates are often applied. To systematically investigate the effect of the salt solution tracer volume on the mixing efficiency in a ladle water model under asymmetrical gas stirring with a low gas flow rate, a 1:3-scaled water model was developed based on a 130-ton industrial ladle. The mixing behaviors corresponding to different tracer volumes were comprehensively analyzed. The results indicate that the relationship between tracer volume and mixing time is non-monotonic. As the tracer volume increases, the mixing time first decreases and then increases, reaching a minimum at 185 mL. When the tracer volume was small, the dimensionless concentration curves at Monitoring Point 4 exhibited two distinct patterns: A parabolic profile, which was when the tracer initially moved through the left and central regions and then slowly crossed the gas plume to reach the monitoring point. A sinusoidal profile, which was when the tracer predominantly circulated along the right side of the ladle. When the tracer volume exceeded 277 mL, the concentration curves at Monitoring Point 4 consistently exhibited a sinusoidal pattern. Compared with moderate gas flow conditions (8.3 L/min), the peak concentration at Monitoring Point 3 was significantly lower under a low gas flow (2.3 L/min), and the overall mixing time was longer, indicating reduced mixing efficiency. Based on the findings, a recommended tracer volume range of 185–277 mL is proposed for low gas flow conditions (2.3 L/min) to achieve accurate and efficient mixing time measurements with minimal disturbance to the flow field. It was also observed that when the tracer concentration was relatively low, the mixing behavior throughout the ladle became more uniform. Full article
(This article belongs to the Special Issue Applications Based on Symmetry/Asymmetry in Fluid Mechanics)
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31 pages, 14974 KiB  
Article
3SqAir Project: A Living Lab Towards Sustainable Smart Strategy for Indoor Climate Quality Assurance in Classrooms
by James Ogundiran, Jean-Paul Kapuya Bulaba Nyembwe, John Omomoluwa Ogundiran, Ruben Alexandre de Souto Santos, Luísa Dias Pereira and Manuel Gameiro da Silva
Atmosphere 2025, 16(5), 584; https://doi.org/10.3390/atmos16050584 - 13 May 2025
Viewed by 363
Abstract
The indoor climate quality in classrooms at the University of Coimbra, Portugal, was investigated as part of the 3SqAir project, supported by the Interreg SUDOE program. This research focused on two equipped classrooms with different ventilation systems: natural and mechanical ventilation. Both classrooms [...] Read more.
The indoor climate quality in classrooms at the University of Coimbra, Portugal, was investigated as part of the 3SqAir project, supported by the Interreg SUDOE program. This research focused on two equipped classrooms with different ventilation systems: natural and mechanical ventilation. Both classrooms were continuously monitored for IEQ parameters: thermal comfort, indoor air quality, noise, and lighting during heating and cooling seasons. Air temperature, relative humidity, CO2 concentration, particulate matter, nitrogen dioxide, volatile organic compounds, formaldehyde, sound pressure level, and illuminance were measured. Outdoor weather conditions were also recorded. The primary focus was on air temperature, CO2 concentrations, and relative humidity, while air change rates (ACH) were estimated using the Tracer Gas Method. The results showed inadequate thermal conditions in both classrooms, particularly during the heating season. Most weekly mean CO2 concentrations were within acceptable limits, while ACH were below standard recommendations in four CO2 decay phases. Simulations of CO2 decay revealed further air quality gaps in each room. Corrective measures within the 3SqAir project framework were suggested for approval and implementation while monitoring continues. This work represents the first phase in an evolving study towards developing sustainable strategies for improving indoor air quality in classrooms. Full article
(This article belongs to the Special Issue Modelling of Indoor Air Quality and Thermal Comfort)
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22 pages, 25259 KiB  
Article
Spatial Modeling of Trace Element Concentrations in PM10 Using Generalized Additive Models (GAMs)
by Mariacarmela Cusano, Alessandra Gaeta, Raffaele Morelli, Giorgio Cattani, Silvia Canepari, Lorenzo Massimi and Gianluca Leone
Atmosphere 2025, 16(4), 464; https://doi.org/10.3390/atmos16040464 - 16 Apr 2025
Viewed by 499
Abstract
GAMs were implemented to evaluate the spatial variation in concentrations of 33 elements in PM10, in their water-soluble and insoluble fractions used as tracers for different emission sources. Data were collected during monitoring campaigns (November 2016–February 2018) in the Terni basin [...] Read more.
GAMs were implemented to evaluate the spatial variation in concentrations of 33 elements in PM10, in their water-soluble and insoluble fractions used as tracers for different emission sources. Data were collected during monitoring campaigns (November 2016–February 2018) in the Terni basin (an urban and industrial hotspot of Central Italy), using an innovative experimental approach based on high-spatial-resolution (23 sites, approximately 1 km apart) monthly samplings and the chemical characterization of PM10. For each element, a model was developed using monthly mean concentrations as the response variable. As covariates, the temporal predictors included meteorological parameters (temperature, relative humidity, wind speed and direction, irradiance, precipitation, planet boundary layer height), while the spatial predictors encompassed distances from major sources, road length, building heights, land use variables, imperviousness, and population. A stepwise procedure was followed to determine the model with the optimal set of covariates. A leave-one-out cross-validation method was used to estimate the prediction error. Statistical indicators (Adjusted R-Squared, RMSE, FAC2, FB) were used to evaluate the performance of the GAMs. The spatial distribution of the fitted values of PM10 and its elemental components, weighted over all sampling periods, was mapped at a resolution of 100 m. Full article
(This article belongs to the Section Air Quality)
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