Search Results (113)

Deep and ultra-deep drilling operations commonly encounter fractured and fracture-vuggy formations, where weak wellbore strength and well-developed fracture networks lead to frequent lost circulation, presenting a key challenge to safe and efficient drilling. Existing diagnostic practices mostly rely on drilling fluid loss dynamic models of single fractures or simplified discrete fractures to invert fracture geometry, which cannot capture the spatiotemporal evolution of loss in complex fracture networks, resulting in limited inversion accuracy and a lack of quantitative, fracture-network-based loss-dynamics support for bridge-plugging design. In this study, a geologically realistic wellbore–fracture-network coupled loss dynamic model is constructed to overcome the limitations of single- or simplified-fracture descriptions. Within a unified computational fluid dynamics (CFD) framework, solid–liquid two-phase flow and Herschel–Bulkley rheology are incorporated to quantitatively characterise fracture connectivity. This approach reveals how instantaneous and steady losses are controlled by key geometrical factors, thereby providing a computable physical basis for loss-zone inversion and bridge-plugging design. Validation against experiments shows a maximum relative error of 7.26% in pressure and loss rate, indicating that the model can reasonably reproduce actual loss behaviour. Different encounter positions and node types lead to systematic variations in loss intensity and flow partitioning. Compared with a single fracture, a fracture network significantly amplifies loss intensity through branch-induced capacity enhancement, superposition of shortest paths, and shortening of loss paths. In a typical network, the shortest path accounts for only about 20% of the total length, but contributes 40–55% of the total loss, while extending branch length from 300 mm to 1500 mm reduces the steady loss rate by 40–60%. Correlation analysis shows that the instantaneous loss rate is mainly controlled by the maximum width and height of fractures connected to the wellbore, whereas the steady loss rate has a correlation coefficient of about 0.7 with minimum width and effective path length, and decreases monotonically with the number of connected fractures under a fixed total width, indicating that the shortest path and bottleneck width are the key geometrical factors governing long-term loss in complex fracture networks. This work refines the understanding of fractured-loss dynamics and proposes the concept of coupling hydraulic deviation codes with deep learning to build a mapping model from mud-logging curves to fracture geometrical parameters, thereby providing support for lost-circulation diagnosis and bridge-plugging optimisation in complex fractured formations. Full article

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare vasculitis, and contemporary population data from Central and Eastern Europe are limited. Aim: To describe hospital-based incidence, patient characteristics and comorbidities among EGPA hospitalizations in Poland (2014–2023), including differences by age, sex and place of residence. Methods: This retrospective, population-based study used nationwide hospital discharge records with an EGPA diagnosis. First EGPA-coded hospitalizations were used to estimate annual incidence per 1,000,000 inhabitants. Demographics, duration of stay and accompanying comorbidities (cardiovascular disease, pulmonary disease, and asthma) were analyzed for all EGPA hospitalizations. Place of residence was classified as urban or rural. Group differences and temporal trends were assessed using appropriate parametric and non-parametric tests and regression models, with a two-sided p value < 0.05 considered statistically significant. Results: Between 2014 and 2023, 911 patients had a first EGPA-coded hospitalisation in Poland, corresponding to a mean annual hospital-based incidence of 2.38 per 1,000,000 inhabitants (range 1.28–3.38); incidence declined significantly from 2014 to 2019 (p < 0.001) and was disrupted during the COVID-19 period. Overall, 3524 EGPA hospitalisations were recorded, and women were more frequently hospitalised than men (54.5% vs. 45.2%; p < 0.001). Mean age at hospitalisation increased over time, with patients in 2023 being about 5–6 years older than in 2014 (p ≤ 0.009). Median length of stay was 8 days for first admissions and 5 days for all EGPA stays and shortened significantly over the study period (p < 0.001). Cardiovascular disease, pulmonary disease and asthma were present in 23.6%, 35.3% and 32.3% of patients, respectively. Cardiovascular disease was more common in men and in rural residents (both p < 0.001) and was associated with older age (p < 0.001), whereas pulmonary disease was associated with younger age (p < 0.001). Among women, the proportions with pulmonary disease and asthma decreased over time (p = 0.009 and p = 0.025). Conclusions: EGPA in Poland is rare, with hospital-based incidence comparable to other European and Asian populations. The hospitalized EGPA population is aging and cardiovascular comorbidity is increasingly prominent, especially in older and rural patients, while recorded pulmonary disease and asthma in women are decreasing. Full article

Wireless sensor networks play a crucial role in IoT applications. Traditional range query methods have limitations in multi-sensor data fusion and energy efficiency. This paper proposes a new range query method for two-layer wireless sensor networks. The method supports data fusion operations directly on storage nodes. Communication costs between sink nodes and storage nodes are significantly reduced. Reverse Z-O coding optimizes the encoding process by focusing only on the most valuable data. This approach shortens both encoding time and length. Data security is ensured using the Paillier homomorphic encryption algorithm. A comparison chain for the most valuable data is generated using Reverse Z-O coding and HMAC. Storage nodes can perform multi-sensor data fusion under encryption. Experiments were conducted on Raspberry Pi 2B+ and NVIDIA TX2 platforms. Performance was evaluated in terms of fusion efficiency, query dimensions, and data volume. The results demonstrate secure and efficient multi-sensor data fusion with lower energy consumption. The method outperforms existing approaches in reducing communication and computational costs. Full article

To address the limitations inherent in traditional simulation control schemes for dual-engine parallel operation systems in diesel engines—such as protracted development cycles, suboptimal interface compatibility, insufficient real-time performance, and inadequate support for dynamic condition simulation in applications like marine power systems—this paper proposes an embedded real-time controller based on model-based design. This methodology facilitates efficient development and high-precision real-time control of parallel operation systems. A multi-domain coupled simulation model integrating diesel power and parallel control algorithms is built in MATLAB/Simulink, with optimized C code auto-generated via Embedded Coder. Hardware centers on STM32F407VE, enabling 4–20 mA speed acquisition, CAN communication, and Ethernet transmission. Experimental results indicate that the architecture shortens development cycles from 8 to 3 weeks, with 895 microseconds of simulation steps meeting 1-millisecond real-time requirements. Vessel tests achieve ±1.8 r/min synchronization error and ±1.2% load distribution error at low cost. It adapts to varied diesel power via modular substitution and supports RS485/CAN-FD. In conclusion, the controller effectively handles real-time simulated diesel engine parallel systems and excels in efficiency, compatibility, and cost, offering a viable technical pathway for modernizing parallel power systems in applications such as marine vessels and power generation. Full article

Retrieval-Augmented Generation (RAG) combined with Large Language Models (LLMs) introduces a new paradigm for clinical-trial data analysis that is both real-time and knowledge-traceable. This study targets a multi-site, real-world data environment. It builds a hierarchical RAG pipeline spanning an electronic health record (EHR), National Health Insurance (NHI) billing codes, and image-vector indices. The LLM is optimized through lightweight LoRA/QLoRA fine-tuning and reinforcement-learning-based alignment. The system first retrieves key textual and imaging evidence from heterogeneous data repositories and then fuses these artifacts into the contextual window for clinical report generation. Experimental results show marked improvements over traditional manual statistics and prompt-only models in retrieval accuracy, textual coherence, and response latency while reducing human error and workload. In evaluation, the proposed multimodal RAG-LLM workflow achieved statistically significant gains in three core metrics—recall, factual consistency, and expert ratings—and substantially shortened overall report-generation time, demonstrating clear efficiency advantages versus conventional manual processes. However, LLMs alone often face challenges such as limited real-world grounding, hallucination risks, and restricted context windows. Similarly, RAG systems, while improving factual consistency, depend heavily on retrieval quality and may yield incoherent synthesis if evidence is misaligned. These limitations underline the complementary nature of integrating RAG and LLM architectures in a clinical reporting context. Quantitatively, the proposed system achieved a Composite Quality Index (CQI) of 78.3, outperforming strong baselines such as Med-PaLM 2 (72.6) and PMC-LLaMA (74.3), and reducing the report drafting time by over 75% (p < 0.01). These findings confirm the practical feasibility of the framework to support fully automated clinical reporting. Full article

The terminal maneuvering area (TMA) serves as a critical transition zone between upper enroute airways and airports, representing one of the most complex regions for managing high volumes of arrival and departure traffic. This paper presents the multi-route TMA scheduling problem as an optimization challenge aimed at optimizing TMA interventions, such as rerouting, speed control, time-based metering, dynamic minimum time separation, and holding procedures; the objective function minimizes schedule deviations and the accumulated holding time. Furthermore, the problem is formulated as a mixed-integer linear program (MILP) to facilitate finding solutions. A rolling horizon control (RHC) dynamic optimization framework is also introduced to decompose the large-scale problem into manageable subproblems for iterative resolution. To demonstrate the applicability and effectiveness of the proposed scheduling models, a hub airport—Chengdu Tianfu International Airport (ICAO code: ZUTF) in the Cheng-Yu Metroplex—is selected for validation. Numerical analyses confirm the superiority of the proposed models, which are expected to reduce aircraft delays, shorten airborne and holding times, and improve airspace resource utilization. This study provides intelligent decision support and engineering design ideas for the macroscopic-level collaborative optimization framework of the Integrated Arrival–Departure and Surface (IADS) system. Full article

Hybrid Propellant Rocket Motors (HPRMs) have been advancing rapidly in recent years. These improvements are finally increasing their competitiveness in the global launch-vehicle market. However, some topics, such as the pre-combustion chamber design, still require more in-depth studies. Few studies have examined this subject. This work proposes a low-computational-cost algorithm that calculates the minimum pre-combustion chamber length, with a vaporization and feed-system coupled instability model. This type of analysis is a key tool for minimizing a vehicle’s size, weight, losses, and costs. Additionally, coupling with internal ballistics codes can be implemented. Furthermore, the results were compared with real HPRMs to verify the algorithm’s reliability. The shortened pre-chamber architecture trimmed the inert mass and reduced the feed-system pressure requirement, boosting overall propulsive energy efficiency by $\approx 8\%$ relative to conventional L*-based designs. These gains can lower stored-gas enthalpy and reduce life-cycle CO and CO₂-equivalent emissions, strengthening the case for lighter and more sustainable access-to-space technologies. Full article

Background and Objectives: Low back pain (LBP) is a highly prevalent musculoskeletal condition that frequently recurs, leading to increased healthcare utilization and socioeconomic burden. While short-term management strategies are well-documented, long-term recurrence patterns remain insufficiently studied. This study aims to describe the long-term recurrence patterns and healthcare utilization associated with LBP in a nationwide cohort over a 17-year period. Materials and Methods: This descriptive, retrospective longitudinal cohort study utilized data from the Korean National Health Insurance Service (NHIS) database (2002–2018). We included 3,086,665 patients who sought medical care for LBP (ICD-10 code M54.5) at least once in 2010. Patients with a history of disability rating assessments were excluded. The primary outcomes included the number of LBP episodes, episode duration, recurrence patterns, and changes in healthcare utilization. We assessed the number of healthcare visits per episode and the interval between episodes over time. Results: Among the study population, 79.4% experienced recurrent LBP, with an average of 5.0 ± 4.9 episodes per patient. Recurrence rates increased with each episode. In addition, episode duration lengthened, and intervals between episodes shortened. Healthcare utilization also increased, with patients requiring more visits per episode over time. The demographic and socioeconomic characteristics of the LBP patients in our sample were also described. Conclusions: In this population-based sample, LBP follows a progressive course, with increasing episode frequency, prolonged duration, and escalating healthcare utilization over time. These findings highlight the need for early intensive management and long-term follow-up strategies to mitigate the growing burden of recurrent LBP on individuals and healthcare systems. Full article

Using the two-dimensional Particle Flow Code (PFC2D), a model of red sandstone containing fractures with different inclination angles under impact load was established to study the influence of fracture inclination angles on the dynamic compressive strength, stress wave attenuation, and crack evolution laws of the model. The results indicate that, under the same impact load, the dynamic compressive strength of the cracked specimens exhibits a “V”-shaped variation, with the specimen at a 45° inclination angle showing the lowest strength. The influence of inclination angles on strength is most significant in the 30° to 45° inclined specimens. As the inclination angle increases, the reflection coefficient rises, the transmission coefficient decreases, stress wave attenuation intensifies, and the time for specimen penetration shortens, making the specimen more prone to failure. The location of crack initiation shifts toward the middle of the fracture as the inclination angle increases, and the cracks tend to develop parallel to the impact load. When the inclination angle is ≥45°, stress concentration at fracture tips prolongs the shear-dominated phase during failure progression. However, the tensile ratio k consistently exceeds 0.7 at ultimate failure, indicating tensile mechanisms remain the dominant failure mode. Both absorbed energy and total crack number generally decrease with increasing inclination angle, while no clear correlation exists between absorbed energy and fragment number. Large fragments are distributed on both sides of the fracture during the fragmentation process. In contrast, small fragments concentrate near the through cracks. Specimens with 45° and 60° inclination angles exhibit a higher number of fragments and more significant fragmentation. In the initial loading stage, the specimen with a 90° inclination angle shows the weakest resistance to failure, while the 0° inclination angle specimen exhibits the strongest resistance. The research findings contribute to elucidating the dynamic failure mechanisms of fractured red sandstone, analyzing slope stability, and optimizing blasting designs. Full article

With the booming development of low earth orbit (LEO) satellite constellations, improving the global navigation satellite system (GNSS) performance based on LEO satellites is attracting more and more research attention. To shorten the convergence time of precise point positioning (PPP) with the help of the LEO navigation augmentation system, the dedicated LEO navigation augmentation signals need to be broadcasted, and the signals need to meet some special design requirements. This paper takes the GNSS L1 and L5 frequency bands as examples to design the LEO navigation augmentation signals. From the perspective of reducing interference to GNSS signals, the carrier frequency of the LEO navigation augmentation signal is selected, and the modulation type is designed. In order to support both high-precision measurement and high data rate, it is proposed that the LEO navigation signal consists of a measurement component and a data component with a high data rate. These two signal components are combined into one composite signal using the multiplexing code shift keying (MCSK) method. On this basis, compatibility between LEO navigation augmentation signals and GNSS signals is evaluated. The impact of LEO navigation augmentation signals on GNSS signals is further analyzed. Full article

Methylmalonic acidemia (MMA) is a genetic condition associated with intellectual disability and a high mortality rate. It is caused by pathogenic variants in the MMUT gene, which codes methylmalonyl-CoA mutase enzyme (MUT). In the Mexican population, the variant NM_000255.4:c.322C>T or p.(Arg108Cys) is the most frequently found, but its structural pathogenic effect is scarcely studied. To describe the clinical picture of p.(Arg108Cys) homozygous patients and to predict its structural pathogenic effect, we performed an analysis of the medical files from six MMA Mexican p.(Arg108Cys) homozygous patients. The structural changes in MUT caused by this variant were analyzed through molecular dynamics simulations (MDS) and docking and compared with the wild-type (Wt) enzyme. The main clinical symptoms presented by the patients were feeding difficulties, lethargy, and neurodevelopmental delay, with a predominance of early-onset phenotype and a mortality rate of 83%. We found significant structural changes in MUT structure, particularly in the catalytic domain, with increased volume cavity, shortening of the binding substrate tunnel, and aberrant accommodation. Also, the dimerization interface area increased from 1343 Ų in the Wt to 3386 Ų, and the dimer formation involved a different set of amino acids. The NM_000255.4:c.322C>T or p.(Arg108Cys) MMUT variant is associated with a severe outcome in MMA Mexican patients, and the enzyme was associated with ostentatious topological changes in the secondary and tertiary structure, which impacted the catalytic domain, the accommodation of the substrate, and the dimerization interface. Further ex vivo functional studies are needed to confirm these predictions, such as enzymatic activity measurements in fibroblasts of patients. Full article

This study aimed to shorten firefighter search times during indoor fires, allowing more people to be rescued, by enhancing disaster-prevention capabilities using building technologies. In indoor fires, fatalities are often caused by the failure of firefighters to rescue individuals in a timely manner. The question of how to effectively increase the probability of survival while waiting for rescue behind closed doors warrants in-depth research and analysis. Therefore, to ensure that people live in safe environments, there is an urgent need to develop a building door panel material with an emergency call function to prevent such incidents from occurring. Utilizing the PRISMA method, we conducted a comprehensive review of the existing literature to identify the key issues and limitations associated with the current search-and-rescue techniques. Subsequently, the identified primary factors were analyzed using the TRIZ method to determine the key factors that influence the success of rescuing trapped individuals, and a notification system was designed to address this issue. Based on the premise that it is advisable to wait for rescue during a fire, we utilized a smartphone to scan a QR code and transmit the exact location information to the fire department. Through extensive participation and feedback from firefighters, we developed a rescue notification door panel and obtained a patent for it. This system can significantly reduce the time required for search-and-rescue operations in fire incidents. The experimental results show a reduction of one-third in search times. Full article

In industries dealing with motor drive systems, the use of real-time simulators for validating control codes is becoming increasingly mandatory. This is particularly essential for systems with advanced control codes or complex microcontroller unit (MCU) register configurations, as this validation process helps prevent accidents and shorten development time. This study presents a validation process using a real-time simulator for the beatless control of six-step operation. Six-step operation, when applied to high-speed drives, has a limitation on the number of samples per electrical rotation, which causes voltage errors. A representative of these voltage error phenomena is the beat phenomenon, resulting in torque ripple at the first harmonic and high current ripple. To mitigate this beat phenomenon, a synchronous PWM method is sometimes used. However, in practical industrial systems, it may not be feasible to synchronously adjust the inverter’s switching frequency with the rotation speed. This study proposes a beatless control method to eliminate the voltage errors caused by the beat phenomenon during six-step operation at a fixed switching frequency. The specific implementation of this control method is explained based on MCU timer register settings. While previous studies have only proposed beatless control methods, this paper goes further by implementing the proposed beatless method using the MCU (TMS320F28335) to generate gating signals and validating the implementation through simulation on a permanent magnet synchronous motor using a real-time simulator (Typhoon HIL). Full article

Breast cancer therapies have dramatically improved survival rates, but their long-term effects, especially on aging survivors, need careful consideration. This review delves into how breast cancer treatments and aging intersect, focusing on the epigenetic changes triggered by chemotherapy, radiation, hormonal treatments, and targeted therapies. Treatments can speed up biological aging by altering DNA methylation, histone modifications, and chromatin remodeling, affecting gene expression without changing the DNA sequence itself. The review explains the double-edged sword effect of therapy-induced epigenetic modifications, which help fight cancer but also accelerate aging. Chemotherapy and targeted therapies, in particular, impact DNA methylation and histone modifications, promoting chronic inflammation and shortening telomeres. These changes increase biological age, as seen in epigenetic clocks and biomarkers like p21, which also play roles in drug resistance and therapeutic decisions. Chronic inflammation, driven by higher levels of inflammatory cytokines such as TNF-α and IL-6 as well as telomere shortening, significantly contributes to the aging characteristics of breast cancer survivors. Non-coding RNAs, including microRNAs and long non-coding RNAs, are crucial in regulating gene expression and aging pathways altered by these treatments. This review explores new therapies targeting these epigenetic changes, like DNA methylation inhibitors, histone deacetylase inhibitors, and microRNA-based treatments, to reduce the aging effects of cancer therapy. Non-drug approaches, such as dietary changes and lifestyle modifications, also show promise in combating therapy-induced aging. It also highlights the clinical signs of aging-related side effects, such as heart and lung problems, endocrine and reproductive issues, and reduced quality of life. The development of comprehensive methods like the CHEMO-RADIAT score to predict major cardiovascular events after therapy is discussed. Understanding the epigenetic changes caused by breast cancer therapies offers valuable insights for creating interventions to enhance the health span and quality of life for survivors. Continued research is crucial to fully understand these epigenetic alterations and their long-term health impacts. Full article

In the field of natural language processing (NLP), prompt-based learning is widely used for efficient parameter learning. However, this method has the drawback of shortening the input length by the extent of the attached prompt, leading to the inefficient utilization of the input space. In this study, we propose P-Distill, a novel prompt compression method that mitigates the aforementioned limitation of prompt-based learning while maintaining performance via knowledge distillation. The knowledge distillation process of P-Distill consists of two methods, namely prompt initialization and prompt distillation. Experiments on various NLP tasks demonstrated that P-Distill exhibited comparable or superior performance compared to other state-of-the-art prompt-based learning methods, even with significantly shorter prompts. Specifically, we achieved a peak improvement of 1.90% even with the prompt lengths compressed to one-eighth. An additional study further provides insights into the distinct impact of each method on the overall performance of P-Distill. Our code will be released upon acceptance. Full article