Search Results (77)

Gel treatments have been widely applied to control water production in oil and gas reservoirs. However, for water shutoff in dense gas reservoirs, most gel-based treatments focus on individual wells rather than the entire reservoir, exhibiting limited treatment depth, poor durability, and inadequate repeatability Notably, formation damage is a primary consideration in treatment design—most dense gas reservoirs have a permeability of less than 1 mD, making them highly susceptible to damage by formation water, let alone viscous polymer gels. Constrained by well completion methods, gelant can only be bullheaded into deep gas wells in most scenarios. Due to the poor gas/water selective plugging capability of conventional gels, the injected gelant tends to enter both gas and water zones, simultaneously plugging fluid flow in both. Although several techniques have been developed to re-establish gas flow paths post-treatment, treating gas-producing zones remains risky when no effective barrier exists between water and gas strata. Additionally, most water/gas selective plugging materials lack sufficient thermal stability under high-temperature and high-salinity (HTHS) gas reservoir conditions, and their injectivity and field feasibility still require further optimization. To address these challenges, treatment design should be optimized using non-selective gel materials, shifting the focus from directly preventing formation water invasion into individual wells to mitigating or slowing water invasion across the entire gas reservoir. This approach can be achieved by placing large-volume gels along major water flow paths via fully watered-out wells located at structurally lower positions. Furthermore, the drainage capacity of these wells can be preserved by displacing the gel slug to the far-wellbore region, thereby dissipating water-driven energy. This study evaluates the viability of placing gels in fully watered-out wells at structurally lower positions in an edge-water drive gas reservoir to slow water invasion into structurally higher production wells interconnected via numerous microfractures and high-permeability streaks. The gel system primarily comprises polyethyleneimine (PEI), a terpolymer, and nanofibers. Key properties of the gel system are as follows: Static gelation time: 6 h; Elastic modulus of fully crosslinked gel: 8.6 Pa; Thermal stability: Stable in formation water at 130 °C for over 3 months; Injectivity: Easily placed in a 219 mD rock matrix with an injection pressure gradient of 0.8 MPa/m at an injection rate of 1 mL/min; and Plugging performance: Excellent sealing effect on microfractures, with a water breakthrough pressure gradient of 2.25 MPa/m in 0.1 mm fractures. During field implementation, cyclic gelant injections combined with over-displacement techniques were employed to push the gel slug deep into the reservoir while maintaining well drainage capacity. The total volumes of injected fluid and gelant were 2865 m³ and 1400 m³, respectively. Production data and tracer test results from adjacent wells confirmed that the water invasion rate was successfully reduced from 59 m/d to 35 m/d. The pilot test results validate that placing gels in fully watered-out wells at structurally lower positions is a viable strategy to protect the production of gas wells at structurally higher positions. Full article

Introduction: Platelet-derived growth factor receptor beta (PDGFRβ) is a key regulator of fibrogenesis. Non-invasive imaging of PDGFRβ expression may offer a novel approach to assess fibrotic remodeling, particularly in cardiac patients’ post-intervention, where fibrosis poses clinical risk. This study presents the GMP-compliant production of a novel PDGFRβ-targeted PET radiopharmaceutical, [⁶⁸Ga]Ga-DOTA-Z09591 ([⁶⁸Ga]Ga-ATH001), and its preclinical evaluation in mouse and human myocardial tissue, along with initial clinical imaging in patients with ST-elevation myocardial infarction (STEMI). Methods: The precursor was chemically synthesized and radiolabeled with gallium-68 using a fully automated, GMP-compatible system and a pharmaceutical-grade ⁶⁸Ge/⁶⁸Ga generator. Autoradiography, H&E, Sirius Red, Masson’s trichrome, and IHC staining were performed on infarcted mouse hearts and human myocardial biopsies. In vivo PET/MRI with [⁶⁸Ga]Ga-ATH001, ¹⁵O-H₂O, and gadolinium contrast was conducted in STEMI patients one week post-percutaneous coronary intervention. Results: [⁶⁸Ga]Ga-ATH001 was produced with high radiochemical yield and purity. Autoradiography demonstrated specific, receptor-mediated binding of [⁶⁸Ga]Ga-ATH001, co-localizing with PDGFRβ immunoreactivity, collagen deposition, and tissue damage. In STEMI patients, focal tracer uptake was observed in infarcted myocardium correlating with MRI-detected structural abnormalities and perfusion defects on ¹⁵O-H₂O PET. Uptake in unaffected myocardium was low and homogeneous, consistent with minimal physiological PDGFRβ expression. Conclusions: [⁶⁸Ga]Ga-ATH001 was successfully developed and validated for phase 0 clinical study. The tracer demonstrated PDGFRβ-specific binding in human fibrotic myocardium and enabled non-invasive detection of myocardial fibrogenic activity in STEMI patients. These findings support further clinical evaluation of [⁶⁸Ga]Ga-ATH001 as a targeted molecular imaging agent for early assessment of post-infarction fibrosis. Full article

Background/Objectives: Granzyme B (GZB) PET Imaging is a non-invasive tool that can determine tumoral and systemic effects in immunotherapy. We aim to evaluate ⁶⁸Ga-NOTA-CYT-200 PET Imaging as a molecular imaging approach to determine CAR T-cell therapy response in a human melanoma mouse model. Our goal is to provide a method to monitor CAR T-cell therapy for patients with melanoma and other solid tumors. Methods: A human melanoma mouse model was generated by implanting naïve NSG mice (n = 28) with a human melanoma cell line (A375) subcutaneously (s.c.). After tumor implantation, mice were randomly assigned to receive either the treatment (CAR T) or vehicle solution (controls). After treatment, tumor sizes were measured every other day up to 35 days after cell implantation. ⁶⁸Ga-NOTA-CYT-200 PET Imaging was performed on days 2, 7, and 14 after CAR T-cell administration to assess T-cell activity within the tumors and organs. The PET Imaging results were correlated with IHC and immunofluorescent staining and cytokine assessment of tumor samples. Results: Tracer uptake within tumors of the CAR T group was significantly greater on days 2 (3.1 ± 1.2 vs. 1.1 ± 0.4, p = 0.002) and 7 (2.0 ± 1.1 vs. 1.1 ± 0.1, p = 0.01) after treatment, even before the CAR T group first presented with significantly lower tumor volumes on day 11 after treatment (61.8 mm³ ± 8.7 vs. 287.1 mm³ ± 157.6, p = 0.05). GZB (p = 0.03) and CAR T (p = 0.001) staining were also significantly greater in tumors of CAR T-cell-treated mice. Inflammatory cytokines such as IFN gamma (p = 0.03), CXCL10 (p = 0.004), and CCL5 (p = 0.02) concentrations were also significantly greater in CAR T-cell-treated tumors. Conclusions: CAR-T-treated tumors show significantly elevated ⁶⁸Ga-NOTA-CYT-200 uptake compared with controls, consistent with enhanced effector activity. Full article

Achieving sustainable air quality improvements in rapidly industrializing regions requires a clear understanding of the emission sources that drive the formation of PM_2.5 pollution. This study identified the sources of PM_2.5 and its organic carbon (OC) in Zibo, a typical industrial city in Northern China Plain, using the Positive Matrix Factorization (PMF) model during five pollution episodes (P1–P5) from 26 November 2022 to 9 February 2023. A high-temporal-resolution online observation of 61 organic molecular tracers was conducted using an Aerodyne TAG stand-alone system combined with a gas chromatograph–mass spectrometer (TAG-GC/MS) system. The results indicate that during pollution episodes, PM_2.5 was contributed by 32.4% from coal combustion and 27.1% from inorganic secondary sources. Moreover, fireworks contributed 13.1% of PM_2.5, primarily due to the extensive fireworks during the Gregorian and Lunar New Year celebrations. Similarly, coal combustion was the largest contributor to OC, followed by mobile sources and secondary organic aerosol (SOA) sources, accounting for 16.2% and 15.3%, respectively. Although fireworks contributed significantly to PM_2.5 concentrations (31.6% in P4 of 20–24 January 2023), their impact on OC was negligible. Overall, a combination of local and regional industrial combustion emissions, mobile sources, extensive residential heating during cold weather, and unfavorable meteorological conditions led to elevated secondary aerosol concentrations and the occurrence of this haze episode. The high-temporal-resolution measurements obtained using the TAG-GC/MS system, which provided more information on source-indicating organic molecules (tracers), significantly enhanced the source apportionment capability of PM_2.5 and OC. The findings provide science-based evidence for designing more sustainable emission control strategies, highlighting that the coordinated management of coal combustion, mobile emissions, and wintertime heating is essential for long-term air quality and public health benefits. Full article

Diesel-powered machinery is the primary energy source in underground mining, exposing workers to hazardous diesel exhaust emissions. This study evaluates occupational exposure to diesel particulate matter (DPM) and gaseous pollutants (NO, NO₂) at an underground mine before and after implementing Diesel Particulate Filters (DPF) and Selective Catalytic Reduction (SCR) in mining equipment. A comprehensive monitoring campaign was conducted, employing elemental carbon (EC) as a tracer for diesel particulate emissions and electrochemical sensors for gas measurements. Results show a substantial reduction in EC concentrations following the implementation of DPFs, with median EC exposure decreasing from 0.145 mg/m³ in 2021 to 0.034 mg/m³ in 2023, and the proportion of samples exceeding the occupational exposure limit (OEL) falling from 90% to 28%. Similarly, SCR implementation led to a 72% reduction in NO₂ levels and a 77.5% decrease in NO concentrations in certain equipment; however, NO levels remained persistently high near loaders, suggesting that additional mitigation measures are required. These findings underscore the efficacy of DPF and SCR technologies in improving air quality and reducing occupational exposure in underground mining environments. Nevertheless, persistent NO concentrations and maintenance-related challenges highlight the need for a holistic emission control approach, integrating ventilation improvements, expanded DPF adoption, alternative propulsion systems, and enhanced maintenance protocols. This study provides critical insights into the effectiveness of advanced emission reduction strategies and informs future regulatory compliance efforts in the mining industry. Full article

Background/Objectives: This study evaluated a novel PET tracer, ⁶⁸Ga-NOTA-CYT-200, which targets human granzyme B (GZB) as a biomarker for cytotoxic T-cell activation in a clinically relevant model of melanoma-bearing mice with a humanized immune system treated with immune checkpoint inhibitor (ICI) therapy. Methods: The binding affinity of the tracer was determined using an enzymatic colorimetric assay. Tumor-bearing humanized NSG mice underwent PET imaging before and during ICI monotherapy or combination therapy to assess ⁶⁸Ga-NOTA-CYT-200 uptake within tumors and other organs. The tumor growth was carefully monitored. The treatment response was evaluated based on the percentage change in tumor size at days 5 and 15 after the treatment started. A tracer biodistribution study and immunohistochemical staining of the tumors and organs were also performed. Results: The inhibition constant (Ki) of ⁶⁸Ga-NOTA-CYT-200 was estimated at 4.2 nM. PET imaging showed a significantly higher ⁶⁸Ga-NOTA-CYT-200 uptake in mice receiving the combination therapy compared to those receiving monotherapy or a vehicle (p < 0.0001 or p = 0.0005, respectively), which correlated with the greatest reduction in tumor size in the combination ICI group. Regardless of treatment, the responders presented with a significantly higher ⁶⁸Ga-NOTA-CYT-200 uptake at days 4 or 7 after the treatment began (p = 0.0002 and p = 0.0109, respectively). An increased uptake of ⁶⁸Ga-NOTA-CYT-200, especially in the intestines and liver within the combination ICI group, suggested immune-related adverse events (IrAEs). Conclusions: Our study demonstrates that ⁶⁸Ga-NOTA-CYT-200 PET imaging can predict the early treatment response in melanoma models treated with ICI and may also help in detecting IrAEs. Full article

In recent years, the accurate evaluation of artificial fracture networks has become a key challenge in enhancing the effectiveness of reservoir stimulation in shale gas development. This paper systematically reviews the research progress on evaluation methods for artificial fracture networks in shale gas horizontal wells, covering two major technical systems: direct monitoring and dynamic inversion. Direct monitoring methods focus on technologies such as microseismic monitoring, tracers, wide-field electromagnetic methods, and distributed fiber optics. Dynamic inversion methods utilize data from fracturing construction curves, shut-in water hammer effects, and flowback production, and combine numerical simulations with artificial intelligence algorithms to infer fracture network parameters, although the issue of non-uniqueness in solutions remains to be addressed. Research shows that no single technology can comprehensively characterize fracture network features. Future directions should involve the integration of multi-source data (geophysical, chemical, fiber-optic, and dynamic production data) to construct intelligent evaluation frameworks, validated by field experiments and dynamic data simulations. The introduction of artificial intelligence and big data technologies provides new ideas for fracture network parameter inversion, but their effectiveness still requires support from more case studies. This paper provides theoretical guidance and practical reference for the optimization and integration of fracture network evaluation technologies in efficient shale gas development. Full article

Helium, as a strategic resource with broad applications in industry and science, has drawn increasing global attention due to its scarcity and non-renewable nature. Noble gas isotopes, especially those of helium, neon, and argon, provide unique geochemical tracers for understanding helium genesis, migration, and accumulation. This short review summarizes recent advances in the application of noble gas isotope techniques to helium resource research. It covers (1) the fundamental isotope systematics and transport mechanisms, (2) key analytical methods for gas extraction and measurement, and (3) typical case studies illustrating helium source identification and reservoir evaluation. In particular, we highlight three emerging trends: (i) field-adaptable analytical protocols for diverse geological samples, (ii) diffusion models incorporating nanoscale confinement effects, and (iii) isotopic ratio-based frameworks for guiding helium exploration strategies. These integrative approaches offer new insights into the “carrier–pathway–trap” paradigm in helium migration systems and support more effective helium resource assessment. Full article

Accurate methane emission estimates are essential for climate policy, yet current field methods often struggle with spatial constraints and source complexity. Ground-based mobile approaches frequently miss key plume features, introducing bias and uncertainty in emission rate estimates. This study addresses these limitations by using small unmanned aerial systems equipped with precision gas sensors to measure methane alongside co-released tracers. We tested whether arc-shaped flight paths and alternative ratio estimation methods could improve the accuracy of tracer-based emission quantification under real-world constraints. Controlled releases using ethane and nitrous oxide tracers showed that (1) arc flights provided stronger plume capture and higher correlation between methane and tracer concentrations than traditional flight paths; (2) the cumulative sum method yielded the lowest relative error (as low as 3.3%) under ideal mixing conditions; and (3) the arc flight pattern yielded the lowest relative error and uncertainty across all experimental configurations, demonstrating its robustness for quantifying methane emissions from downwind plume measurements. These findings demonstrate a practical and scalable approach to reducing uncertainty in methane quantification. The method is well-suited for challenging environments and lays the groundwork for future applications at the facility scale. Full article

This study assesses the clinical deployment of SubtlePET™, a commercial AI-based denoising algorithm, across three radiotracers—¹⁸F-FDG, ⁶⁸Ga-PSMA-11, and ¹⁸F-FDOPA—with the goal of improving image quality while reducing injected activity, technologist radiation exposure, and scan time. A retrospective analysis on a digital PET/CT system showed that SubtlePET™ enabled dose reductions exceeding 33% and time savings of over 25%. AI-enhanced images were rated interpretable in 100% of cases versus 65% for standard low-dose reconstructions. Notably, 85% of AI-enhanced scans received the maximum Likert quality score (5/5), indicating excellent diagnostic confidence and noise suppression, compared to only 50% with conventional reconstruction. The quantitative image quality improved significantly across all tracers, with SNR and CNR gains of 50–70%. Radiotracer dose reductions were particularly substantial in low-BMI patients (up to 41% for FDG), and the technologist exposure decreased for high-exposure roles. The daily patient throughput increased by an average of 4.84 cases. These findings support the robust integration of SubtlePET™ into routine clinical PET practice, offering improved efficiency, safety, and image quality without compromising lesion detectability. Full article

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

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

Background/Objectives: Molecular imaging, especially PET, has advanced significantly, shifting from metabolic radiotracers like 2-deoxy-2-[¹⁸F]fluoro-D-glucose [¹⁸F]FDG to target-specific probes. Among these, αvβ6-integrin has emerged as a promising target in cancer and non-cancer diseases. This review focuses on the radiochemical properties and initial clinical applications of the [⁶⁸Ga]Ga-Trivehexin PET probe. Methods: The literature review on [⁶⁸Ga]Ga-Trivehexin systematically evaluated both preclinical and clinical studies, with particular emphasis on its radiochemical characteristics and preliminary clinical applications, while highlighting advancements, associated challenges, and the potential for future developments in the field. Results: This study highlights the significant advancements achieved with [⁶⁸Ga]Ga-Trivehexin in the field of molecular imaging. The optimized multimeric system has substantially enhanced the radiotracer’s pharmacokinetic properties, binding affinity, and selectivity for αvβ6 integrin, demonstrating up to an 18-fold improvement compared to previous monomeric tracers. The synthesis protocol has been refined to achieve high radiochemical purity (>95%), essential for safe clinical use. Preliminary clinical applications, particularly in head and neck cancer (HNC) and pancreatic ductal adenocarcinoma (PDAC), have shown promising results, with high detection rates and improved differential diagnosis compared to [¹⁸F]FDG. Furthermore, [⁶⁸Ga]Ga-Trivehexin PET/CT has shown potential in non-oncological conditions, such as idiopathic pulmonary fibrosis (IPF) and primary hyperthyroidism, suggesting broader clinical applicability. Conclusions: [⁶⁸Ga]Ga-Trivehexin is a promising PET probe for imaging αvβ6-integrin in cancers and non-oncological diseases like idiopathic pulmonary fibrosis (IPF) and primary hyperparathyroidism (PHP). Full article

Subsurface contamination can migrate upward into overlying buildings, exposing the buildings’ inhabitants to contaminants that can cause detrimental health effects. This phenomenon is known as vapor intrusion (VI). When evaluating a building for VI, one must understand that seasonal and short-term variability are significant factors in determining the reasonable maximum exposure (RME) to the occupants. RME is a semi-quantitative term that refers to the lower portion of the high end of the exposure distribution—conceptually, above the 90th percentile exposure but less than the 98th percentile exposure. Samples were collected between December 2020 and April 2022 at six non-residential commercial buildings in Fairbanks, Alaska. The types of samples collected included indoor air (IA); outdoor air; subslab soil gas; soil gas; indoor radon; differential pressure; indoor and outdoor temperature; heating, ventilation, and air conditioning (HVAC) parameters; and other environmental factors. The buildings in close proximity to the volatile organic compound (VOC) source/release points presented less variability in indoor air concentrations of trichloroethylene (TCE) and tetrachloroethylene (PCE) compared to the buildings farther down gradient in the contaminated groundwater plume. The VOC data pattern for the source area buildings shows an outdoor air temperature-dominated behavior for indoor air concentrations in the summer season. HVAC system operations had less influence on long-term indoor air concentration trends than environmental factors, which is supported by similar indoor air concentration patterns independent of location within the plume. The use of soil temperature and indoor/outdoor temperatures as indicators and tracers (I&Ts) across the plume as predictors of the sampling period could produce a good estimation of the RME for the building occupants. These results, which show the use of soil temperature and indoor/outdoor temperatures as I&Ts, will help advance investigative methods for evaluation of VI in similar settings and thereby improve the protection of human health in indoor environments. Full article

Background/Objectives: Over the past four years, ⁶⁸Ga-fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) has been established at a tertiary cancer care facility in Jordan. This retrospective study aims to explore tracer uptake metrics across various epithelial neoplasms, identify diagnostic pitfalls associated with ⁶⁸Ga-FAPI PET/CT, and evaluate the influence of ⁶⁸Ga-FAPI PET/CT staging results on changes in therapeutic intent compared to gold standard molecular imaging modalities. Methods: A total of 48 patients with biopsy-confirmed solid tumors underwent 77 ⁶⁸Ga-FAPI PET/CT examinations for molecular imaging assessment, encompassing neoplasms originating from the gastrointestinal tract, head and neck, hepatobiliary system, pancreas, breast, and lung. Results: Notably, pancreaticobiliary tumors exhibited the highest tracer uptake, with mean maximum standardized uptake values (SUVmax) and tumor-to-background ratios (TBR) surpassing 10. A comparative sub-analysis of ⁶⁸Ga-FAPI PET metrics in 20 treatment-naïve patients revealed a significant correlation between ⁶⁸Ga-FAPI uptake metrics and tumor grade (Spearman’s rho 0.83; p = 0.00001). Importantly, the results from ⁶⁸Ga-FAPI PET/CT influenced treatment decisions in 35.5% of the cases, primarily resulting in an escalation of management plans. A total of 220 diagnostic challenges were identified across 88.3% of the scans, predominantly within the musculoskeletal system, attributed to degenerative changes (99 observations). Conclusions: This comprehensive analysis highlights the potential significance of ⁶⁸Ga-FAPI PET/CT in oncological imaging and treatment strategy, while also emphasizing the necessity for meticulous interpretation to mitigate diagnostic challenges. Full article