Search Results (137)

We advance a mathematical framework for collective conviction by deriving a continuum theory from the network-based model introduced by us recently. The resulting equation governs the evolution of belief through a degenerate anisotropic logistic–diffusion process, where diffusion slows as conviction saturates. In one spatial dimension, we prove global well-posedness, demonstrate spectral front pinning that arrests the spread of influence at finite depth, and construct explicit traveling-wave solutions. In two dimensions, we uncover a geometric mechanism of curvature–induced quenching, where belief propagation halts along regions of low effective mobility and curvature. Building on this insight, we formulate a variational principle for optimal control under resource constraints. The derived feedback law prescribes how to spatially allocate repression effort to maximize inhibition of front motion, concentrating resources along high-curvature, low-mobility arcs. Numerical simulations validate the theory, illustrating how localized suppression dramatically reduces transverse spread without affecting fast axes. These results bridge analytical modeling with societal phenomena such as protest diffusion, misinformation spread, and institutional resistance, offering a principled foundation for selective intervention policies in structured populations. Full article

As urbanization accelerates globally, higher education agglomeration (HEA) emerges as a critical mechanism for integrating regional economic theories with practical strategies, driving innovation and sustainable development. This paper examines how HEA promotes innovation, human capital accumulation, industrial restructuring, and equitable income distribution across 193 cities in the “Two Transverse and Three Lengthways” urban clusters from 2006 to 2020. Using dynamic panel regression and spatial econometric models, the results show that HEA yields significant local and spatial spillover benefits, particularly in core cities that facilitate knowledge diffusion and resource sharing. Heterogeneity analysis reveals that these positive spillovers are strongest in first-tier, highly developed clusters and third-tier, early-stage clusters but weaker or even negative in second-tier, rapidly expanding regions. These spatial effects grow over time, reflecting the evolving patterns of regional integration. Theoretically, the paper advances the understanding of spatial synergy and spillover mechanisms in HEA in urban clusters. Practically, the findings highlight the need to tailor higher education strategies to the developmental stage of each urban cluster to optimize resource allocation and foster inclusive growth. This paper provides policy insights for using HEA as a catalyst for coordinated urban development. Full article

This publication covers experimental investigations on the design resistance of arc-brazed fillet welds (CuAl7) on low-alloyed structural steel (S355) subject to predominantly static loading and regarding steel construction regulations (Eurocode). In current steel construction regulations, there is no standardized design approach for arc-brazed fillet welds available, so arc-brazed connections are rarely used despite the benefits they offer in several regards compared to conventionally welded connections. Therefore, a resistance model for arc-brazed fillet welds was calibrated based on tensile tests that were conducted on gas metal arc-brazed specimens with transverse and longitudinal fillet welds. Based on the statistical evaluation of the test results according to Annex D of EN 1990, a newly determined correlation factor β_b is proposed, which can be used for the static design of arc-brazed fillet welds made of CuAl7. This approach leads to a significantly higher calculated design resistance than previous non-standardized design approaches allowed. Also, it was found that the failure behavior of the fillet welds is critical for the design resistance of the joints and that there is a need for further investigations with regard to a targeted joint failure, which, analogous to welded fillet welds, should take place along the throat of the weld and not along the less resistant diffusion zone of the joint. Thus, the results underscore the potential for the use of arc-brazed connections in steel construction in regard to their load-bearing capacity, but also highlight the necessity of continued research regarding factors influencing their structural integrity. Full article

Background/Objectives: Ischemic colitis, typically caused by thrombosis or reduced blood flow in the inferior mesenteric artery, is the most common ischemic lesion at the colorectal level. This case contributes to existing knowledge by highlighting the rare co-occurrence of a thrombosed aortic aneurysm and ischemic colitis, pointing to a direct vascular etiology rather than a multifactorial or idiopathic cause. Methods: A thorough electronic search was conducted on PubMed to identify risk factors and etiological determinants of ischemic colitis. Results: We present the case of a 70-year-old male with diffuse abdominal pain and multiple cardiac comorbidities. A CT scan revealed aeroenteritis, aerocolia, fusiform aneurysmal dilation of the abdominal aorta (18 cm long, 7.3 cm in diameter, from below the renal arteries to the bifurcation), parietal thrombosis, a circulating lumen of 2.7 cm, and inferior mesenteric artery thrombosis. Intraoperatively, necrosis was found in the upper rectum, sigmoid colon, descending colon, and the middle third of the left transverse colon, with clear demarcation between healthy and necrotic tissue. A subtotal proctocolectomy with transverse colostomy was performed. Conclusions: This case highlights ischemic colitis as a vascular disorder, urging broader differential diagnosis when common causes are unclear. Timely imaging, a multidisciplinary approach, and attention to vascular risks are key to identifying rare causes like aneurysmal thrombosis. While thrombosed abdominal aortic aneurysms can cause mesenteric ischemia, their link to ischemic and ulcerative colitis is unique, emphasizing the importance of accurate risk assessment in treatment planning. Full article

Background and Clinical Significance: The occurrence of cerebral venous sinus thrombosis (CVST), both with or without thrombocytopenia, following COVID-19 vaccination, is well documented and more common in recipients of vector vaccines. Cases of CVST following immunization with the COVID-19 messenger RNA (mRNA) vaccine are rare; most of these cases occur within 28 days of the first dose of the vaccine. Case Presentation: We present the case of a 38-year-old male with a history of two episodes of deep vein thrombosis in the lower limbs, but without a specific thrombophilic condition, who developed CVST 13 days after the second dose of the Pfizer/BioNTech BNT162b2 vaccine. He suffered from diffuse tension-type headache of progressively increasing intensity, and his objective neurological findings were normal. Magnetic resonance venography showed thrombosis of the transverse and right sigmoid sinuses, and magnetic resonance imaging (MRI) of the brain revealed no cerebral infarction. Two months later, a follow-up MR venography showed partial recanalization of the affected sinuses, and a brain MRI showed no infarction. Conclusions: Given the temporal sequence and the absence of other possible causes, we speculate that the second dose of the COVID-19 BNT162b2 vaccine may have triggered the development of CVST. Full article

To enhance the passing capacity of the Bailongtan Ship Lock on the Hongshui River, this study focused on the design scheme of its water conveyance system reconstruction and expansion project. A three-dimensional mathematical model meeting the experimental accuracy requirements was established based on the RNG k-ε turbulence model and the Volume of Fluid (VOF) free-surface tracking method. A 1:30 scale ship lock water conveyance system physical model was built and used the independently developed system for hydraulic test monitoring, acquisition, and control. Experimental research on the hydraulic characteristics and shape optimization of the water conveyance system was carried out. The experimental results show that, under the condition of a maximum head difference of 16.0 m between the upstream and downstream of the ship lock, in the design scheme, the flow in the corridor after the filling valve fails to diffuse adequately, forming a high-velocity zone and a significant pressure difference between the inner and outer sides, which poses an operational risk. By optimizing the shape of the corridor after the valve (deepening the bottom end by 2.0 m and adjusting the turning angle from 75° to 70°), the range of the high-velocity zone can be shortened from 3.0 m to 1.5 m. The pressure difference between the inner and outer sides of the corridor at the horizontal turning section is reduced by 19.2% from 5.35 m to 4.32 m of the pressure head at the moment of maximum flow rate, and the velocity in the horizontal section is less than 15 m/s. Physical model tests confirmed these improvements, with mooring forces within safety limits (longitudinal ≤ 32 kN, transverse ≤ 16 kN). The research findings indicate that integrating numerical simulation with physical model testing can effectively mitigate risks in the original design of the ship lock water conveyance system. This approach notably enhances the reliability and safety of the design scheme, as demonstrated by the significant reduction in high-velocity zones and pressure differentials. Moreover, it offers a robust scientific basis and practical technical reference for in-depth hydraulic research and targeted optimization of ship lock water conveyance systems. Full article

Numerical models are commonly used to support the management of diffuse pollution sources in large agricultural landscapes. This paper investigates the suitability of a three-dimensional groundwater streamline-based nonpoint source (NPS) assessment tool for agricultural aquifers. The streamline approach is built on the assumption of steady-state groundwater flow and neglects the effect of transverse dispersion but offers considerable computational efficiency. To test the practical applicability of these assumptions, two groundwater transport models were developed using the standard three-dimensional advection–dispersion equation (ADE): one with steady-state flow and the other with transient flow conditions. The streamline approach was compared with both ADE models, under various nitrate management practice scenarios. The results show that the streamline approach predictions are comparable to the steady-state ADE, but both steady-state methods tend to overestimate the concentrations across wells by up to 10% compared to the transient ADE. The prediction of long-term attenuation of nitrate under alternative land management scenarios is identical between the streamline and the transient ADE results. Full article

South American wood and wood-based products play major roles in the global forest sector. Most research related to Paraguayan wood is focused on forest restoration, urban arborization, silviculture, and botanical taxonomy. Often overlooked but of major importance is the cellular structure of the trees that comprise remaining forests in Paraguay. Wood greatly contributes to forest value, yet wood anatomy studies remain novel in the country. To further document Paraguayan wood anatomy, two downed species of multipurpose Myrtaceae trees were sampled from a subtropical semi-deciduous forest in Areguá, Central Paraguay. In this article, heartwood xylem anatomy was observed and documented using low-cost methodology to support the regional realities of the emerging field in rural communities, especially local Paraguayan peoples. This included specific gravity, density, and basic light microscopic features. Sample material was processed near the pith at breast height to display cellular features in the transverse, radial, and tangential planes. Four features were measured with light microscopy and ImageJ: tangential vessel element diameter, vessel element length, ray seriation, and ray height. Results showed structural similarity between species, with diffuse porosity, solitary pores, simple perforation plates, alternate intervessel pits, and apotracheal diffuse parenchyma in aggregates. These results represent the first sampling of Myrtaceae from Paraguay in a methodology that can be easily replicated by the native population, thereby enabling further wood anatomy studies in the region. Full article

The diffusion characteristics of thermal discharge from coastal power plants were studied by analyzing the Ningde Nuclear Power Plant and Kemen Power Plant, which are located in different geographical regions in China. The former is in the open sea, and the latter is in a well-sheltered bay. In the vicinity of the outfall areas of the two power plants, large-area surface temperature observations and tidal current observations were conducted. The results indicate that the thermal discharge diffusion characteristics of coastal power plants located in different geographical environments are significantly different. In the well-sheltered sea area of the Kemen Power Plant, the water temperature diffuses faster along the coast, in line with the direction of tidal movement, and slower in the offshore direction under the influence of rectilinear tidal currents within the bay, resulting in a significantly greater longitudinal diffusion distance of thermal discharge along the shore than the transverse diffusion distance offshore. In the area surrounding the Ningde Nuclear Power Plant, rotational currents diffuse the thermal discharge in various directions, causing the range of temperature rise to expand toward the outer sea. Dominant tidal currents within the tidal cycle in the sea area can influence the distribution of high-temperature rise zones near outfalls. The distribution of high-temperature rise zones predominantly occurs on the side with the higher average tidal velocity, either the ebb tide side if its velocity is greater than that of the flood tide or the flood tide side otherwise. Full article

Introduction: Primary colorectal lymphoma (PCL) is a very rare disease with limited information regarding its macroscopic features. This retrospective descriptive study aims to identify the macroscopic characteristics of PCL and explore treatment trends and outcomes with respect to histopathologic subtypes. Methods: This IRB-approved study from a large academic medical center identified 66 patients with colorectal lymphoma from 1998 to 2022 from a tumor registry. Thirty-four patients met the inclusion criteria of having PCL with available endoscopic data. The macroscopic features of each lesion were identified. Treatment trends and outcomes were examined at the patient level. Data were described using frequency and percentages for categorical characteristics and the median and interquatile range (IQR) for continuous outcomes. Results: A total of 77 PCL lesions were identified. Most were identified on screening or surveillance colonoscopies or colonoscopies performed after abnormal imaging (61.8%). Diffuse large B cell lymphoma (DLBCL) had the highest prevalence (N = 24), followed by follicular lymphoma (n = 21), mantle cell (n = 16), mucosa-associated lymphoid tissue (MALT) (n = 14), then Burkitt’s (n = 2). More mantle cell (93.8%) and follicular (90.5%) lymphomas were sessile. More MALT lymphomas were ulcerated (71.4%). A higher proportion of follicular (76.2%) and mantle cell (71.4%) lymphomas were diminutive (≤5 mm). More MALT (78.6%), DLBCL (75.0%), and Burkitt’s (100%) were large (≥20 mm). More lesions were found in the sigmoid colon (26.0%), followed by the rectum (22.1%), transverse colon (18.2%), cecum (18.2%), descending colon (10.4%), and ascending colon (5.2%). Overall, most underwent immunotherapy (61.3%) and did not have radiation therapy (81.3%), endoscopic resection (75.0%), and surgery (68.8%). Patients with DLBCL demonstrated higher rates of chemotherapy (70.6%), immunotherapy (87.5%), and remission after intervention (52.9%). Conclusions: Primary colorectal lymphomas display distinct macroscopic features and appear in different locations depending on the histopathologic subtype. Most cases are identified at early stages on screening colonoscopies and demonstrate a 75% two-year survival rate. Full article

The hygrothermal aging model, based on Fick’s second law of diffusion, characterizes the degradation of engineering constants in T700 carbon fiber/epoxy resin composites. It focuses on changes in the tensile modulus, shear modulus, and transverse Poisson’s ratio due to moisture absorption and temperature variations. The model validates through mass change observations before and after seawater immersion, along with surface morphology assessments and tensile experiments. The results reveal that the saturated moisture absorption rate for single-layer laminates in seawater immersion is 0.35%. Short-term seawater immersion at room temperature (≤60 days) does not induce cracks or defects (≥10 μm) on the composite’s surface. The composite’s modulus decreases as moisture absorption increases, with the longitudinal tensile modulus dropping by an order of 10⁻⁵%, while the other engineering constants decrease by an order of 10⁻³%. The modulus also decreases with rising temperature; the closer the temperature is to the matrix’s glass transition, the faster the modulus declines, with the longitudinal tensile modulus decreasing by 0.84%, and the other engineering constants decreasing by 100%. This research provides valuable insights for the engineering applications of composite materials in marine environments. Full article

The separation and purification of molecular compounds and their functionalized derivatives is a common challenge in organic synthesis. In particular, calix[4]resorcinarenes present a high potential for chemical derivatization at their upper edge by aminomethylation reactions, and these compounds and their derivatives require appropriate analytical methodologies for their analysis, separation, and purification. In this study, C-tetra(propyl)calix[4]resorcinarene was synthesized and functionalized with maleimide groups by optimized aminomethylation reactions, obtaining a mixture of mono-, di-, tri-, and tetrasubstituted compounds. Initial separation by RP-HPLC with a core-shell column showed poorly resolved peaks, indicating a loss of separation efficiency. Therefore, a monolithic C18 column was used, which significantly improved the separation, thanks to its larger pore volume and continuous structure facilitating the diffusion of these bulky molecules, notably improving efficiency. Finally, the six compounds functionalized with maleimide groups were efficiently separated and enriched by RP-SPE by analytical method transfer, and the two peptides of six and the thirteen residues derived from LfcinB (20–25): RRWQWR were synthesized by SPPS-Fmoc/tBu and purified. These were modularly linked by the Michael thiol-maleimide addition reaction obtaining six (peptide)_n-resorcinarene conjugates. The analytical method by RP-HPLC with a monolithic C18 column, the separation and purification by RP-SPE were used transversally in all the steps to obtain compounds with adequate purities and quantities. Finally, the antibacterial activities of the six conjugates were evaluated against E. coli and E. faecalis strains, and it was determined that three aminomethylated compounds and one monosubstituted conjugate showed activity against E. faecalis. Our work established a new modular conjugation strategy between calix[4]resorcinarenes and peptides by thiol-maleimide click chemistry, and a methodology of separation, purification, and enrichment for these products by RP-HPLC and RP-SPE, which permitted us to obtain quantities with purities appropriate for their characterization by NMR, LC-MS and antibacterial activity assays. Full article

Background/Objective: Lysosomal storage diseases (LSDs) are a group of rare, inborn, metabolic errors characterized by deficiencies in normal lysosomal function and by the intralysosomal accumulation of undegraded substrates, resulting in the damage of multiple organ systems. The spectrum of clinical manifestations is extremely heterogeneous. LSD diagnosis and management still present many issues. Methods: A group of Italian experts and patients’ representatives met to discuss some critical aspects, and among the most impactful are early diagnosis, the transition of the patient from pediatric to adult age, territorial management, and the multidisciplinary approach. Results: Possible solutions to diagnostic delays may be a widespread newborn screening and screening programs on selected populations. The lack of a structured transition process could be helped by the drafting of shared diagnostic and therapeutic care pathways beyond the availability of databases accessible to the different levels that manage a patient. Territorial management could benefit from telemedicine, but a homogeneous diffusion of home therapy, not yet everywhere possible, is essential. A fundamental role is played by the patient associations, which should be increasingly involved in the political choices. It is also crucial to create structured multidisciplinary teams of experts for disease management and comorbidities. A transversal need appears to be greater training on LSDs. In Italy, the “Statement of Udine” was developed to guide further steps towards improvements in inherited metabolic medicine in adults, referencing the experience from the United Kingdom. Conclusions: Much can be done for the early diagnosis and management of LSDs with an effective treatment, but many aspects need improvement for the overall management of the patient. An investment in dedicated resources, formal recognition, and training is needed to address these unmet needs. Full article

Truffles of the Tuber genus (Pezizales, Ascomycetes) are among the most valuable and expensive foods, but their shelf life is limited to 7–10 days when stored at 4 °C. Alternative preservation methods have been proposed to extend their shelf life, though they may alter certain quality parameters. Recently, a hypogeal display case equipped with an ultrasonic humidity system (HDC) was developed, extending the shelf life to 2–3 weeks, depending on the truffle species. This study assesses the efficacy of HDC in preserving Tuber melanosporum and Tuber borchii ascomata over 16 days, using quantitative magnetic resonance imaging (QMRI) to monitor water content and other parameters. Sixteen T. melanosporum and six T. borchii ascomata were stored at 4 °C in an HDC or a static fridge (SF) as controls. QMRI confirmed that T. borchii has a shorter shelf life than T. melanosporum under all conditions. HDC reduced the rate of shrinkage, water, and mass loss in both species. Additionally, the Apparent Diffusion Coefficient (ADC), longitudinal relaxation time (T1), and transverse relaxation time (T2), which reflect molecular changes, decreased more slowly in HDC than SF. QMRI proves useful for studying water-rich samples and assessing truffle preservation technologies. Further optimization of this method for industrial use is needed. Full article

The evolution of structural changes and the textural features during the ripening process of four varieties of Spanish sheep cheese were studied using Magnetic Resonance Imaging (MRI). Specifically, longitudinal (T₁) and transverse (T₂) relaxation times and apparent diffusion coefficient maps were analyzed. Also, proton density was used to improve the description of the structure of the cheeses. The MRI results displayed important information about cheese matrix structure, associated with different manufacturing processes (industrial vs. traditional), ripening times (RTs, from 2 to 180 days), and geographical origins. A significant interaction between RT and cheese variety related to the variations in physicochemical and textural parameters was found. Linear regression models were developed per the abundant literature. Logarithmic regression models showed the highest R² when monitoring the dependency on T₁ and T₂ parameters of water content, water activity, RT, and some texture parameters. Therefore, these results support that MRI is a useful technology to monitor the ripening process, predict textural behavior and physicochemical variables, and characterize the structure of different varieties of sheep cheese. Full article