Search Results (205)

Crohn’s disease (CD) is a complex inflammatory bowel disease, defined by chronic transmural inflammation and marked heterogeneity in both anatomical distribution and disease behavior, with potential involvement of any segment of the gastrointestinal tract and multiple phenotypes. Advanced cross-sectional imaging nowadays plays a central role in CD management, reliably assessing both luminal and extraluminal inflammatory manifestations, supporting initial diagnosis, phenotypic characterization, and longitudinal monitoring of disease activity, complications and treatment response. Over the last two decades, Intestinal Ultrasound (IUS), MR Enterography (MRE), and Computed Tomography Enterography (CTE) have become central components of the diagnostic pathway. MRE has emerged as the most comprehensive, radiation-free modality for evaluating intestinal extent, inflammatory activity, and complications in Crohn’s disease. Multiparametric MRE, combining T2-weighted imaging, contrast-enhanced sequences, diffusion-weighted imaging, and cine acquisitions, enables a real “Crohn’s disease staging”, namely a thorough evaluation of the transmural inflammation, of fibrotic and fistulizing lesions in the small and large bowel, as well as in the perianal region. IUS provides a dynamic, widely accessible, safe and repeatable imaging technique that is particularly well suited for tight-monitoring strategies, early assessment of therapeutic response, and routine follow-up, especially in experienced centers. Notably CTE, despite concerns related to cumulative ionizing radiation exposure, remains indispensable in acute clinical settings owing to its rapid acquisition, broad availability, and high diagnostic accuracy for detecting abscesses, perforation, and bowel obstruction. Combined, these three modalities offer a complementary and patient-tailored framework for optimal CD management. This review outlines the pathological complexity of Crohn’s disease, traces the evolution of imaging approaches, and provides a comparative overview highlighting the specific strengths and limitations of each modality. Full article

Background/Objectives: There is an increasing need for cross-sectional imaging in pediatric patients with congenital heart disease. This patient group is highly sensitive to ionizing radiation. The purpose of this article was to evaluate differences in radiation dose and image quality between a first-generation photon-counting (PC)-CT system and a 256-slice single-source energy-integrating detector (EID)-CT in these patients. Methods: We retrospectively assessed effective dose, CT dose index-volume (CTDI_vol), dose length product (DLP), and image quality of all prospectively electrocardiography-gated CTs of the thorax in all patients < 18 years of age examined between February 2021 and August 2024 (n = 43). Two independent observers subjectively scored image quality, vascular contrast, and noise on a 5-point Likert scale. In addition, we assessed the signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) quantitatively. Results: All dose parameters were significantly lower in the PC-CT (n = 27) versus the EID-CT (n = 16) group (mean effective dose: 0.8 ± 0.64 versus 2.2 ± 0.88 mSv, p < 0.001; mean CTDI_vol: 1.22 ± 0.96 versus 4.8 ± 1.08 mGy, p < 0.001; mean DLP: 30.7 ± 31.9 versus 73.7 ± 50.7 mGy*cm, p < 0.001). Overall subjective image quality and contrast were rated higher in the PC-CT group (p = 0.046 and < 0.001, respectively). Quantitative CNR was significantly higher in the PC-CT group (mean 39.1 ± 12.9 versus 26.2 ± 10.8, p = 0.002). Conclusions: PC-CT enables high-quality examinations for the evaluation of congenital heart disease with a highly significant dose reduction compared with a 256-slice single-source EID-CT. Full article

Primary hyperparathyroidism (PHPT) in the pediatric population is a rare but clinically important endocrine disorder that poses significant diagnostic and therapeutic challenges. In contrast to adult PHPT, which is often detected incidentally, pediatric patients are frequently symptomatic at diagnosis, with manifestations reflecting prolonged exposure to hypercalcemia and elevated parathyroid hormone levels. Neonatal forms, particularly neonatal severe hyperparathyroidism, represent life-threatening conditions requiring prompt biochemical recognition and urgent intervention. The heterogeneity of clinical presentation and the rarity of the disease contribute to delayed diagnosis and increased risk of end-organ complications. Although hereditary syndromes are proportionally more frequent in children than in adults, sporadic PHPT remains the most common etiology in pediatric patients and is typically caused by a single parathyroid adenoma. Genetically determined forms, including multiple endocrine neoplasia syndromes, hyperparathyroidism–jaw tumor syndrome, and calcium-sensing receptor-related disorders, are often associated with multiglandular disease, earlier onset, and a higher risk of persistence or recurrence. Biochemical confirmation remains the cornerstone of PHPT diagnosis, while diagnostic imaging plays an important role in preoperative localization and surgical planning. High-resolution cervical ultrasound is the preferred first-line imaging modality in pediatric patients due to its excellent diagnostic performance and absence of ionizing radiation. Functional and advanced cross-sectional imaging techniques should be applied in a stepwise manner in selected cases with inconclusive first-line imaging or suspected ectopic disease, balancing diagnostic yield against radiation exposure. Surgical management remains the definitive treatment for pediatric PHPT. The extent of surgery is determined by disease etiology, localization findings, and intraoperative assessment, with focused parathyroidectomy favored in sporadic single-gland disease and more extensive approaches required in genetically determined forms. This review highlights a structured diagnostic and therapeutic pathway for pediatric PHPT, emphasizing the integration of biochemical testing, imaging strategies, genetic evaluation, and individualized surgical management to optimize outcomes and reduce long-term morbidity. Full article

We report experimental measurements of the absolute photoionization cross sections for chlorine ions in different stages of ionization, over photon energy ranges corresponding to the L-shell (2s and 2p subshells) excitations. Single, double and triple photoionization channels were investigated for the ions Cl⁺, Cl²⁺, Cl³⁺ and Cl⁴⁺. The measurements were performed on the PLéIADES beamline at the SOLEIL radiation storage ring facility, using the Multi-Analysis Ion Apparatus (MAIA). Resonance energies and line strengths are provided for the isonuclear sequence and the evolution of the inner shell photoionization behaviour is demonstrated for the chlorine ions as the degree of ionization is increased. While dominated by photoionization from the corresponding ground state ions, the photoion yields may also contain contributions from low-lying metastable states. The results provide useful data on these ions for plasma modelling and can serve as benchmarking experimental data for future atomic theoretical calculations. Full article

Recent advances in non-local thermodynamic equilibrium (non-LTE) plasma simulations, for example in modeling kilonova ejecta, have emphasized the need for consistent and reliable atomic data. Unlike LTE modeling, non-LTE calculations must include a consistent treatment of various photon-induced and collisional processes in order to describe realistic electron and photon distributions in the plasma. However, the available atomic data are often incomplete, inconsistently formatted, or even fail to indicate the main dependencies on the level structure and plasma parameters, thus limiting their practical use. To address these issues, we have extended Jac, the Jena Atomic Calculator (version v0.3.0), to provide direct access to relevant cross sections, plasma rates, and rate coefficients. Emphasis is placed on photoexcitation and ionization processes as well as their time-reversed counterparts—photo-de-excitation and photorecombination. Whereas most of these data are still based on empirical expressions, their dependence on the ionic level structure and plasma temperature is made explicit here. Moreover, the electron and photon distributions can be readily controlled and adjusted by the user. This transparent representation of atomic data for photon-mediated processes, together with a straightforward use, facilitates their integration into existing plasma codes and improves the interpretation of high-energy astrophysical phenomena. It may support also more accurate and flexible non-LTE plasma simulations. Full article

Total electron scattering cross sections (TCSs) for NO₂ molecules have been measured with a magnetically confined electron beam transmission apparatus for impact energies ranging from 1 to 200 eV. The estimated total uncertainty limits are within ±5%. Moreover, integral elastic, ionization, electronic and rotational excitation cross sections in the (20–1000 eV) energy range have been calculated with our independent atom model-based screening corrected additivity rule including interference effects (IAM-SCAR+I) method. The cross-section data set derived from this study is critically compared with the recommended values available in the literature. Full article

Background/Objectives: Serum calcium concentrations have been associated with bone mineral density (BMD), but results seem to depend on sex. Genetic variants in the Ryanodine Receptor1 (RYR1) gene have been previously associated with low BMD in postmenopausal women. Serum RYR1 concentration was found to be higher in osteopenia and osteoporosis groups. The function and biological relevance of RYR1 in bone remodeling remains unknown. This cross-sectional study explored the relationship between serum calcium concentrations, BMD, and genetic variants in RYR1 in a Mexican-mestizo population. Methods: Serum samples from 966 participants were obtained from the third measurement of the Health Workers Cohort Study (HWCS) 2017–2019, conducted by the Mexican Social Security Institute (IMSS). All participants included in this study were of Mexican Mestizo origin and had data on BMD. We measured ionized calcium and genotyped the genetic variants rs2288888 (g.38455542G>A) and rs11083462 (g.38469040C>T) of the RYR1 gene. BMD of the total hip, lumbar spine, and femoral neck was measured using a Lunar DPX NT DEXA device. Results: Our results show that elevated serum calcium concentrations in females are associated with lower BMD at the hip and femoral neck. In contrast, higher calcium concentrations in males were associated with greater total hip BMD. In our study, the variants rs2288888 and rs11083462 were associated with higher serum calcium concentrations (under-adjusted and unadjusted data) in males but not females. Conclusions: Serum calcium levels are associated with BMD, depending on sex. The RYR1 gene variants rs2288888 and rs11083462 may have a protective effect in men. Full article

Recent progress in laboratory medicine provides powerful tools for the detailed evaluation of cardiovascular risk in military populations. This study aimed to characterize cardiometabolic biomarker profiles across four Polish military groups through chemometric analysis. The study included 392 participants (336 men, 56 women, aged 19–56 years). In total, 23 serum biomarkers from lipid, metabolic, hepatic, hormonal, and bone axes, and lactate dehydrogenase (LDH) were analyzed. Random forest (RF) modeling and effect-size profiling identified group-specific signatures. Group 4 (exposed to extreme acceleration forces and ionizing radiation) exhibited a systemic stress and metabolic-load profile with higher N-terminal pro-B-type natriuretic peptide (NT-proBNP, 36.7 ± 48.2 pg/mL) and calcium (Ca, 10.4 ± 0.88 mg/dL), and lower parathyroid hormone (PTH, 15.4 ± 10.1 pg/mL) and C-terminal telopeptide of type I collagen (β-CTX, 0.22 ± 0.19 ng/mL). Group 2 (exposed to fuels and exhaust gases) and group 3 (exposed to vibration, noise, ionizing radiation) showed an atherogenic–hepatometabolic axis with elevated apolipoprotein B (apoB, 1.04 ± 0.31; 0.97 ± 0.29 g/L), non-high-density lipoprotein cholesterol (N-HDL, 151.0 ± 46.7; 147.0 ± 41.4 mg/dL), and alanine aminotransferase (ALT). Group 1 (exposed to a biological hazard) displayed higher glucose (Glu, 96.0 ± 25.6 mg/dL) and triglycerides (TG, 151.0 ± 113.0 mg/dL) with lower magnesium (Mg, 2.03 ± 0.27 mg/dL). RF modeling confirmed these constellations. This study was exploratory in nature, providing a foundation for future longitudinal research. These findings provide a rationale for tailored cardiovascular surveillance, although causal inference is limited by the cross-sectional design. Full article

In this work, we present a theoretical model to investigate electron emission in collisions between dressed ions with He atoms and H₂ molecules. The projectile potential is described as the sum of a long- and short-range terms. The last term includes a screening function that has its maximum at short distances. The present model is based on the Continuum Distorted Wave Eikonal Initial State (CDW-EIS) theory, but the Eikonal approximation is only made within the long-range transition amplitude. This now leads to physically correct predictions, whenever dressed projectiles are involved, in the binary-encounter peak. Indeed, double-differential cross-sections spectra is calculated and compared with existing experimental data, finding that this model is capable of reproducing some well-known phenomena depending on the projectile charge state. Namely, the dependence of the binary-encounter peak magnitude with the projectile charge state. Full article

We present a combined experimental and modeling study of premixed atmospheric-pressure tetralin flames. Chemical speciation in near-stoichiometric (φ = 0.8–1.0) tetralin/O₂/Ar flames was characterized by probe-sampling molecular-beam mass spectrometry (MBMS) with soft ionization (12.3–18 eV). Total ionization cross-sections (TICSs) for heavy intermediates were computed ab initio to enable quantitative MBMS processing. Laminar burning velocities (LBVs) of tetralin/air flames were measured in a range of equivalence ratios (φ = 0.75–1.5) on a nozzle burner via the stretch-corrected total area method. This is the first reported LBV data for tetralin/air flames (maximum LBV was 47.3 ± 2 cm/s at φ = 1.1). The experimental mole fraction profiles and LBVs were interpreted using three detailed mechanisms. None of the mechanisms were able to correctly describe the LBV profile, and a number of discrepancies were observed in the mole fraction profiles. Reaction network and sensitivity analyses were performed to identify specific sub-mechanisms requiring refinement. In particular, the subchemistry of naphthalene and indene strongly affects the accuracy of model predictions, whereas the flame speciation data indicate large uncertainties in the simulated concentrations of these species. Full article

Proton therapy enables precise dose delivery to tumors while sparing healthy tissues, offering significant advantages over conventional radiotherapy. Accurate prediction of biological doses requires detailed knowledge of radiation interactions with biological targets, especially DNA, a key site of radiation-induced damage. While most biophysical models (LEM, mMKM, NanOx) rely on water as a surrogate, this simplification neglects the complexity of real biomolecules. In this work, we calculate the stopping power and range of protons in liquid water, dry DNA, and hydrated DNA using semi-empirical cross sections for ionization, electronic excitation, electron capture, and electron loss by protons and neutral hydrogen in the 10 keV–100 MeV energy range. Additionally, ionization cross sections for uracil are computed to explore potential differences between DNA and RNA damage. Our results show excellent agreement with experimental and ab initio data, highlighting significant deviations in stopping power and range between water and DNA. Notably, the stopping power of DNA exceeds that of water at most energies, reducing proton ranges in dry and hydrated DNA by up to 20% and 26%, respectively. These findings provide improved input for Monte Carlo simulations and biophysical models, enhancing RBE predictions and dose accuracy in hadrontherapy. Full article

This cross-sectional pilot study aimed to examine associations between urinary metabolites of organophosphate (OP) pesticides and semen quality in 42 healthy young men. Participants answered questionnaires, provided semen and urine samples, and had anthropometric measures taken. Urine and seminal plasma were assayed for dialkylphosphate (DAP) metabolites of OP pesticides using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Semen quality parameters were analyzed according to the World Health Organization protocol, and seminal oxidative stress was assayed using MiOXSYS, a galvanic cell-based technology that yields an integrated measure of oxidants and antioxidants. Associations of OP pesticide metabolites with continuous and dichotomous sperm concentration, percent motility, and percent normal morphology, and with seminal oxidative-reduction potential (ORP) were analyzed statistically. OP pesticide exposure was associated with lower overall semen quality. Specifically, ∑DAP metabolites, driven by diethyl metabolites, was inversely associated with percent sperm motility, but this relationship was not mediated by seminal ORP. Seminal ORP was inversely associated with sperm concentration, but OP pesticide exposure was not associated with seminal ORP. Full article

We report calculations for electron–radon scattering using a complex relativistic optical potential method. The energy range of this study is 0–1000 eV, with results for the elastic (total, momentum-transfer and viscosity-transfer) cross section, summed discrete electronic-state integral excitation cross sections and electron-impact ionization cross sections presented. Here, we obtain our cross sections from a single theoretical relativistic calculation. Since radon is a heavy element, a relativistic treatment is very desirable. The electron transport coefficients are subsequently calculated for reduced electric fields ranging from 0.01 to 1000 Td, using a multi-term solution of Boltzmann’s equation. Full article

A fully connected neural network was trained to model the K-shell ionization cross sections based on two input features: the atomic number and the incoming electron overvoltage. The training utilized a recent, updated compilation of experimental data covering elements from H to U, and incident electron energies ranging from the threshold to relativistic values. The neural network demonstrated excellent predictive performance, compared with the experimental data, when available, and with full theoretical predictions. The developed model is provided in the ikebana code, which is openly available and requires only the user-selected atomic number and electron energy range as inputs. Full article

We present calculations of the ionization cross sections for collisions of electrons and positrons with the acene molecules naphthalene, anthracene, tetracene, pentacene, and hexacene. The computations are performed using the binary-encounter Bethe (BEB) model and its modifications for positrons. The results show that all acenes exhibit maxima in their ionization cross sections at the same incident energy, regardless of molecular size. Furthermore, we find that the magnitude of the cross sections scales linearly with the number of rings in the acene molecules. Full article