Search Results (19,456)

Continental shale oil reservoirs contain multiscale pore–fracture systems with strong heterogeneity and fractal characteristics, which complicate oil mobilization during post-fracturing shut-in imbibition. In this study, shale cores from the LGS Formation (a lacustrine continental shale oil formation in China) were used to investigate capillary-force-regulated pressurized shut-in imbibition by integrating interfacial tension measurements, apparent contact angle tests, capillary pressure calculation, time-lapse nuclear magnetic resonance (NMR), NMR-based fractal characterization, visual observations, and pre-/post-imbibition permeability measurements. Two surfactant-based imbibition agents with different capillary-force regulation mechanisms were compared to represent different capillary-force regulation pathways. Agent 1 mainly modified apparent wettability, increasing the contact angle from 51.0° to 66.1°, whereas Agent 2 reduced the oil–water interfacial tension from 31.85 to 22.12 mN/m while maintaining a favorable apparent contact angle of 49.3°. Time-lapse NMR results showed that oil recovery increased with shut-in time and reached approximately 12–30% after 144 h. Agent 2 generally produced higher recovery than Agent 1, with the optimum response at 0.15 wt%. NMR-derived fractal dimensions ranged mainly from 2.32 to 2.61, confirming the multiscale heterogeneity of the LGS shale pore system. Pore-size-resolved recovery further showed that oil mobilization was dominated by pores larger than 20 nm and microfracture-related spaces, whereas pores smaller than 20 nm contributed only limited bulk recovery. This indicates an apparent nanopore mobilization threshold near 20 nm, controlled by fractal pore complexity, pore-throat connectivity, oil adsorption, capillary pressure, and molecular accessibility of imbibition agents. Visual and permeability evidence further showed that pressurized imbibition can selectively activate connected pore–fracture pathways. Post-imbibition dry-core permeability increased in all tested samples, although the enhancement was highly heterogeneous. These results demonstrate that shut-in imbibition in LGS shale is governed by coupled interfacial regulation, fractal pore heterogeneity, pore-size-dependent oil accessibility, and selective pore–fracture structural modification. Full article

Bile duct tumor thrombus (BDTT) is a rare manifestation of hepatocellular carcinoma (HCC) that causes obstructive jaundice and is associated with a poor prognosis, although a treatment algorithm has yet to be established. We review the treatment landscape for HCC with BDTT, including surgical, transarterial, systemic, and radiotherapy options, and report, to our knowledge, the first case series of magnetic resonance-guided radiotherapy (MRgRT) for this condition. Four patients with unresectable HCC and BDTT were treated on a 0.35-T MR-linac with real-time cine-MRI gating (50 Gy in 5 fractions, n = 3; 40 Gy in 5 fractions, n = 1), with tumor response assessed by modified RECIST. All patients completed treatment without interruption. The best response was complete response in two patients and partial response in two, and obstructive jaundice resolved in both affected patients. The maximum radiation-attributed toxicity was a transient grade 3 bilirubin elevation that resolved without biliary intervention, and no treatment-related deaths occurred. Overall survival ranged from 5.5 to 29 months, with the two Child-Pugh class A patients without portal vein tumor thrombosis surviving 22 and 29 months. MRgRT for HCC with BDTT appears feasible with acceptable short-term safety and merits prospective evaluation. Full article

Light chain (AL) amyloidosis is a systemic disorder caused by plasma cell dyscrasia, with cardiac involvement being the primary determinant of prognosis. Survival outcomes vary significantly across disease stages. This heterogeneity underscores a critical need for early diagnosis, precise risk stratification, and response-adapted therapy. In this context, multimodality imaging has emerged as an indispensable non-invasive tool, providing crucial insights for clinical decision-making. This review synthesizes recent advances in the application of key imaging modalities—echocardiography, magnetic resonance imaging, and nuclear medicine imaging—for evaluating AL amyloidosis. We highlight how these techniques have shifted the paradigm from anatomical assessment to quantitative, multiparametric tissue characterization, ultimately guiding personalized patient management. Full article

The persistent accumulation of tetracycline (TC) antibiotics in aquatic environments poses severe ecological and public health risks, necessitating the development of multifunctional platforms capable of simultaneous detection and degradation. Herein, we report magnetically recoverable plasmonic Fe₃O₄/Cu₂O-Ag nanocomposites (NCs) that integrate visible-light-driven photocatalysis with ultrasensitive surface-enhanced Raman scattering (SERS) detection. Hierarchical flower-like Fe₃O₄ nanocrystals were employed as magnetic supports, followed by in situ growth of Cu₂O nanocrystals and controlled deposition of Ag nanocrystals. The optimized composite (FCA-2) exhibited enhanced visible-light absorption (E_g = 1.86 eV), suppressed electron–hole recombination, and improved photocurrent response, which were attributed to Schottky barrier formation at the Cu₂O-Ag interface and localized surface plasmon resonance (LSPR) effects. Under simulated solar irradiation, FCA-2 NCs achieved 91.79% degradation of TC within 60 min, following pseudo-first-order kinetics (k = 20.37 × 10⁻³ min⁻¹). Finite-difference time-domain (FDTD) simulations revealed that optimal Ag loading maximized plasmonic “hot spot” density, thereby enhancing electromagnetic field intensity and SERS performance. The FCA-2 substrate enabled ultrasensitive TC detection with a limit of detection of as low as 10⁻¹⁰ M. Moreover, the superparamagnetic Fe₃O₄ core allowed for rapid magnetic separation and sustained performance over multiple SERS–photocatalysis cycles, with negligible signal attenuation after 30 days. This work presents a rational strategy for constructing plasmonic magnetic NCs that synergistically couple photocatalytic remediation, ultrasensitive sensing, and magnetic recyclability, offering significant potential for integrated environmental monitoring and sustainable water treatment applications. Full article

White adipose tissue (WAT) is categorized as either subcutaneous or visceral fat. One technique used to measure adipose tissue is nuclear magnetic resonance (NMR), which involves placing an animal in a tube for six minutes. This procedure is stressful for rats. Therefore, we evaluated whether determining the weight of subcutaneous WAT in sacrificed rats via NMR is a valid approach. Rats fed a standard diet showed similar WAT measurements when alive and after being sacrificed. Moreover, three groups of rats were fed different diets; one group was fed a cafeteria diet. The weight of WAT in the carcasses measured via NMR (mainly subcutaneous WAT) and the weight of the fat depots, measured after sacrifice (visceral WAT), presented similar percentages of subcutaneous and visceral WAT among the three groups (with different levels of adiposity). In conclusion, this research is a proof of concept regarding the determination of subcutaneous WAT weight via NMR, regardless of adiposity. Full article

A novel low-molecular-weight water-soluble oligosaccharide fraction (LBPP-1) was prepared from lotus bee pollen via microwave-assisted extraction, followed by Sevag deproteinization and diethylaminoethyl (DEAE)-cellulose-52 chromatography purification. Ion chromatography (IC) indicated a glucose-rich composition (84.6 mol% glucose), with minor amounts of arabinose, glucosamine, and galactose. Fourier transform-infrared spectroscopy (FT-IR), methylation analysis, and ¹H nuclear magnetic resonance (NMR) collectively supported the assignment of LBPP-1 as a glucan-rich, structurally heterogeneous oligosaccharide fraction containing candidate →4)-Glcp-rich domains and minor arabinose/galactose-related linkages. However, the marked difference between the IC composition and the sugar-type distribution estimated from PMAA peak areas limits quantitative interpretation of the residue proportions and branching architecture. Furthermore, in vitro biological assays demonstrated that LBPP-1 significantly attenuated lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 macrophages. It effectively reduced the secretion of nitric oxide (NO) and the levels of inducible nitric oxide synthase (iNOS), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in RAW264.7 macrophages. Reverse transcription–quantitative polymerase chain reaction (RT-qPCR) analysis further revealed that LBPP-1 selectively suppressed the mRNA expression of cyclooxygenase-2 (COX-2), IL-1β, IL-6, iNOS, and transforming growth factor (TGF)-β1. These findings collectively suggest that LBPP-1, as a bioactive carbohydrate fraction derived from lotus bee pollen, holds promise as a natural functional food ingredient for managing inflammation-related conditions. Full article

Natural hydrogen is a promising zero-carbon resource, but its small molecular size and high diffusivity make nuclear magnetic resonance (NMR) logging interpretation difficult. This study develops a pore-network and random-walk simulation framework to analyze hydrogen and methane responses in hydrogen-rich sandstones. The model couples pore structure, fluid properties, magnetic-field gradients, and acquisition parameters. Transverse relaxation time (T₂) spectra are inverted with Tikhonov regularization and generalized cross-validation. The effects of waiting time (TW), echo time (TE), pore size, gradient strength, and burial depth are quantified. Results show clear T₂ separation among water, oil, methane, and hydrogen. Dual-TW difference spectra improve fluid discrimination, and hydrogen shows the strongest TW sensitivity. TW mainly controls amplitude, while TE and gradient mainly control diffusion attenuation. Because hydrogen diffuses faster, it is more sensitive than methane to both factors. Greater depth and larger pores shift peaks to longer T₂, but strong diffusion attenuation weakens hydrogen’s pore-size sensitivity. These results clarify the distinct NMR response mechanism of hydrogen. These findings can directly support NMR logging workflows for natural hydrogen reservoir identification by guiding TW–TE parameter design and gradient control, and by improving H₂-CH₄ discrimination in mixed-gas intervals. They can also reduce interpretation uncertainty in deep, heterogeneous formations, thereby improving confidence in identifying and evaluating natural hydrogen reservoirs. Full article

Background/Objectives: Cardiac involvement in sarcoidosis necessitates meticulous management, with accurate and timely diagnosis being crucial. The hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) modality is an emerging diagnostic tool for cardiac sarcoidosis, offering potential advantages over the use of independent PET and MRI techniques for both diagnosis and prognosis. Methods: Following the PRISMA guidelines for study selection, a comprehensive search using the terms “hybrid PET/MRI” and/or “cardiac sarcoidosis” identified a total of 10 eligible studies. Results: Patients were primarily middle-aged males. Overall, hybrid PET/MR enhanced diagnostic accuracy by identifying specific subgroups, detecting active disease, enabling detailed quantitative analysis, and assessing regional involvement. Additionally, it offered valuable insights that could improve phenotyping and prognostic predictions. The primary limitation was the longer duration of a single scan; however, the total scanning time was reduced compared to conducting two separate procedures. Conclusions: Hybrid PET/MR imaging offers several significant advantages over separate imaging modalities when diagnosing cardiac sarcoidosis, including increased diagnostic accuracy and comprehensive tissue characterization. Further comparative studies are needed to fully understand its clinical impact and potential limitations. Full article

Background/Objectives: Rectovaginal fistula (RVF) is a challenging condition that can substantially impair quality of life and often requires individualized surgical management. Accurate preoperative imaging is essential for identifying fistulous tracts, assessing pelvic floor involvement, and guiding surgical planning. However, conventional imaging modalities, including magnetic resonance imaging (MRI), may still have limitations in detecting small, occult, intermittently patent, or anatomically complex fistulas, particularly under static imaging conditions. This study aimed to evaluate the diagnostic performance of transperineal pelvic floor ultrasound (TPUS) combined with ultrasound contrast agent enema (UCAE) and its potential value in preoperative assessment of RVF. Methods: In this prospective single-center study, 62 women with surgically confirmed RVF were enrolled between January 2022 and April 2025. All patients underwent TPUS combined with UCAE before surgery, while subsets also underwent contrast-enhanced CT, contrast-enhanced MRI, or barium enema according to clinical indications. Imaging findings were compared with intraoperative findings as the reference standard. Fistula detection, morphological classification, size, anatomical location, pelvic floor injury assessment, and concordance between ultrasound-based surgical proposals and actual surgical procedures were systematically analyzed. Comparative analyses with conventional imaging modalities were performed based on available non-paired subgroups. Results: UCAE detected RVF in 60 of 62 patients, yielding a detection rate of 96.8%. In the available comparative cohort, UCAE demonstrated higher detection rates than conventional imaging modalities, particularly in small and complex fistulas. UCAE showed high agreement with intraoperative findings in terms of fistula morphology, size, and anatomical location. TPUS provided additional and complementary information regarding levator ani and anal sphincter injuries and yielded higher sensitivity and accuracy in pelvic floor injury assessment within the studied cohort. Ultrasound-based surgical proposals showed directional concordance with final intraoperative decisions in 88.7% of cases. No adverse events were observed during UCAE. Conclusions: TPUS combined with UCAE appears to be a safe and feasible preoperative imaging approach for RVF. By integrating fistula detection, anatomical classification, pelvic floor assessment, and surgical planning, this combined ultrasound approach may serve as a complementary imaging strategy to conventional imaging modalities, particularly for small or intermittently patent fistulas. Further multicenter studies and standardized imaging protocols are warranted to validate its clinical utility and generalizability. Full article

Human interaction with the environment depends on the integration of sensory input, cognitive processing, and motor output within dynamic sensorimotor loops. These processes are supported by distributed neural circuits and shaped by learning, memory, and neuroplasticity across the lifespan. This review synthesizes current understanding of the mechanisms underlying sensorimotor integration and highlights how experience-dependent plasticity supports functional recovery and performance optimization in both health and disease. Disruptions such as traumatic brain injury, neurodegenerative disease, and aging may frequently result in combined cognitive and motor impairments. Here, we review non-invasive interventions that leverage neuroplasticity, including physical activity, motor training, and cognitive training, with increasing emphasis on integrated cognitive–motor approaches. Emerging technologies such as virtual reality provide ecologically valid, immersive environments that simultaneously engage perception, cognition, and action, with the potential to enhance training outcomes. However, variability in effectiveness and limited evidence for far transfer remain key challenges. To address these limitations, we highlight the integration of immersive training with objective biological measures. In particular, proton nuclear magnetic resonance (¹H NMR)-based metabolomics offers a promising, non-invasive approach to identify biomarkers of neuroplastic adaptation. The integration of robust biomarker tools may facilitate the development and assessment of effective precision cognitive–motor interventions to optimize rehabilitation approaches and help build resilience in vulnerable individuals. Full article

Introduction: Hepatic infarction is an uncommon but clinically important cause of focal ischemic liver injury. In internal medicine, it usually emerges in acutely ill or complex hospitalized adults with sepsis, shock, malignancy, thrombosis, vasculitis, transplantation, or recent hepatobiliary or interventional procedures who develop a new focal hepatic lesion and abnormal liver tests. Aims: This review aims to provide internists with a practical diagnostic and management pathway for recognizing hepatic infarction, distinguishing it from abscess and malignancy, selecting appropriate imaging, identifying vascular complications, and avoiding unnecessary biopsy or drainage when conservative management is safer. Methods: We performed a structured narrative review of adult hepatic infarction and related ischemic liver entities using targeted searches in PubMed/MEDLINE and Scopus. The search strategy, screening process, and evidence limitations are reported explicitly. Because the available evidence is dominated by case reports, small series, radiology reviews, and guidance on related vascular liver diseases, the synthesis is qualitative and the proposed pathway is conceptual rather than prospectively validated. Results: Hepatic infarction is most often recognized when systemic hypoperfusion, splanchnic vasoconstriction, microvascular dysfunction, or local macrovascular compromise coexist. Multiphasic computed tomography (CT) is usually the first-line acute-care modality, while MRI, contrast-enhanced ultrasound, Doppler ultrasound, CT angiography, or vascular imaging should be selected according to diagnostic uncertainty and suspected arterial or portal venous complications. The main diagnostic pitfalls are misclassification as abscess, malignancy, hematoma, or postoperative collection. Conclusions: In the appropriate clinical context, a wedge-shaped or geographic non-enhancing hepatic lesion should trigger vascular-ischemic reasoning before being labeled as abscess or tumor. The proposed internist-led pathway is intended as a pragmatic conceptual framework for diagnostic reasoning and multidisciplinary communication, not as a validated guideline or evidence-based algorithm. Full article

Background: Total neoadjuvant therapy is becoming a preferred option for locally advanced rectal cancer, particularly in patients with high-risk baseline features. However, real-world evidence comparing tumor response, MRI-defined high-risk feature clearance, surgical outcomes, and survival after total neoadjuvant therapy versus conventional long-course chemoradiotherapy remains limited. This study aimed to compare outcomes between total neoadjuvant therapy and long-course chemoradiotherapy in patients with locally advanced rectal cancer treated in routine clinical practice. Methods: This is a retrospective, single-centre cohort study focused on patients with stage II–III locally advanced rectal adenocarcinoma treated with curative-intent neoadjuvant therapy using either total neoadjuvant therapy or long-course chemoradiotherapy. Tumor response was assessed using restaging MRI, clinical complete response, and pathological complete response. Surgical outcomes and overall survival were evaluated. Results: A total of 110 patients were included. Patients treated with total neoadjuvant therapy had a higher baseline disease burden reflected by a greater proportion of cT4 tumors (40.6% vs. 19.2%; p = 0.014). Radiologic tumor-length response and clearance of MRI-defined high-risk features were comparable between treatment strategies. Clinical and pathological complete response rates were numerically higher in the total neoadjuvant therapy group, but the differences were not significant (cCR: 15.6% vs. 6.4%, p = 0.151; pCR: 18.5% vs. 9.7%, p = 0.301). Conclusions: In this real-world cohort, TNT was preferentially used in patients with more advanced baseline disease and showed numerically higher complete response rates, although differences were not statistically significant. Radiologic response, surgical outcomes, and short-term survival were comparable between treatment strategies. These findings support the feasibility of TNT in routine clinical practice but should be interpreted as exploratory and hypothesis-generating rather than evidence of treatment superiority. Full article

Background: Accurate segmentation of brain tumors from multi-modal magnetic resonance imaging (MRI) is essential for diagnosis, treatment planning, and therapy monitoring. However, this task remains challenging due to tumor heterogeneity, irregular boundaries, and the complex anatomical structure of surrounding tissues. In particular, precise delineation of tumor sub-regions—including whole tumor, tumor core, and enhancing tumor—continues to be a major limitation of existing automated methods. Methods: In this study, we propose a novel hybrid CNN–Transformer framework that integrates local feature extraction with global contextual modeling for improved brain tumor segmentation. The architecture consists of three main components: a dual-pathway encoder for capturing fine-grained and contextual features, a multi-scale feature fusion module based on spatial pyramid pooling with dense connections, and a boundary-aware attention decoder designed to enhance segmentation accuracy around tumor edges. The model utilizes four MRI modalities (T1, T1ce, T2, and FLAIR) to capture complementary tumor characteristics. In addition, a hybrid loss function combining Dice, focal Tversky, and boundary losses is employed to address class imbalance and improve boundary precision. Results: Experimental results on the BraTS 2023 dataset demonstrate superior performance, achieving Dice scores of 92.3%, 88.7%, and 84.5% for whole tumor, tumor core, and enhancing tumor, respectively, while maintaining high computational efficiency. Conclusion: The proposed framework achieves accurate and robust brain tumor segmentation by effectively integrating local and global features, demonstrating its potential for automated multi-modal MRI analysis in clinical practice. Full article

Alkali-activated concrete (AAC) offers the advantages of high mechanical strength and excellent corrosion resistance, making it a promising low-carbon material. However, its widespread application in practical engineering is severely limited by the serious issues of high shrinkage and susceptibility to cracking. To address the challenges, this work proposes incorporating superabsorbent polymers (SAPs) into AAC to mitigate its shrinkage problems. A comprehensive investigation is conducted on fresh, mechanical and shrinkage properties of SAP-modified AAC. The underlying shrinkage-mitigating mechanism is revealed through various tests including hydration heat, X-ray diffraction, scanning electron microscope (SEM), and nuclear magnetic resonance (NMR) analysis. Results indicate that SAP prolongs concrete setting times. With SAP addition, the overall porosity and weak interfacial transition zones are increased, leading to decreases in the compressive strength by approximately 6.9–20.2% at 28 d. Both splitting tensile and flexural strengths show varying degrees of improvement. Adding 0.1–0.3% SAP reduces the 3 d autogenous shrinkage by about 33.08–41.14%, and 56 d drying shrinkage by 12.4–32.7%. SAPs act as internal water reservoirs, regulating humidity and reducing AAC’s sensitivity to internal relative humidity. Furthermore, SAPs optimize AAC pore structure distributions, as revealed by SEM and NMR analyses. Given the impact of SAP dosage (0–0.3%), autogenous and drying shrinkage prediction models are respectively established based on CEB-FIP 90 and GL 2000 models, showing superior agreement between predicted results and test data, with all the fitting coefficients over 0.9. Full article

Finite element (FE) modeling is widely used in biomechanical research, enabling computational investigations of anatomical structures. To develop accurate FE models, high-resolution medical imaging such as computed tomography (CT) is essential. However, CT exposes patients to ionizing radiation. Recently, radiation-free three-dimensional zero-echo-time magnetic resonance imaging (3D ZTE MRI) has shown promising results for bone visualization. Therefore, this feasibility study investigated whether 3D ZTE MRI is reliable for creating subject-specific FE models. Human femora from four female subjects were imaged using 3D ZTE MRI. Static FE analyses of the femora were performed in Abaqus/CAE, assuming a biphasic homogenous linear-elastic material. A sensitivity analysis was conducted to evaluate varying bone material properties. After loading with 2000 N, the mean displacement of the femoral head amounted to −1.30 ± 0.26 mm (vertical) and −9.03 ± 2.21 mm (horizontal), while the femoral neck exhibited compressive (inferior: −1366.03 ± 182.70 µm/m) and tensile (superior: 1038.69 ± 135.82 µm/m) strains. Overall, the results demonstrate displacement and strain predictions similar to previous experimental and computational studies based on CT data. Therefore, despite several simplifications, these findings confirm the feasibility of radiation-free 3D ZTE MRI for subject-specific FE modeling, enabling future simultaneous assessment of bone morphology and surrounding soft tissues. Full article