Search Results (243)

Background: Measles, mumps, rubella (MMR) and varicella vaccines are often co-administered to optimize coverage, yet safety concerns regarding febrile convulsions persist. In South Korea, MMR and varicella vaccines are administered as separate injections during a single visit (MMR + V). This study evaluated the real-world safety of concurrent MMR + V vaccination, focusing on the domestically implemented MAV/06 and Oka-derived strains. Methods: We conducted a multicenter self-controlled case series (SCCS) study of children aged 12–23 months who received MMR + V and hepatitis A vaccine (HAV) between 2015 and 2024. Using electronic health records, we identified predefined adverse events (AEs), including fever and healthcare visits. Adjusted relative risks (aRRs) were estimated using conditional Poisson regression. Results: Among 3035 children (52.3% male; median age, 12 months), 71.7% received the MAV/06 varicella strain. A distinct peak in AEs occurred 7–13 days after MMR + V administration, with fever showing the greatest increase (aRR, 4.27; 95% CI, 2.76–6.60). The risks of total sick visits (aRR, 2.15; 95% CI, 1.70–2.71) and acute care visits (aRR, 2.13; 95% CI, 1.46–3.10) were similarly confined to this interval and returned to baseline thereafter. Febrile convulsions were uncommon (aRR, 5.37; 95% CI, 1.20–24.01). No excess risks were observed during the HAV or overlap periods, and no synergistic effects of intensive multi-vaccine administration were detected. Conclusions: Concurrent administration of MMR and varicella vaccines in Korean infants—predominantly using the MAV/06 strain—was associated only with expected, transient increases in fever during days 7–13 postvaccination. No serious or sustained safety signals were identified, supporting the continued use of Korea’s separate-injection MMR + V strategy. Full article

Background: Osteochondral lesions of the talus (OLT) remain a challenging condition due to the limited regenerative potential of articular cartilage. Conventional bone marrow stimulation (BMS) techniques often result in fibrocartilage formation with inferior biomechanical properties. This study aimed to evaluate the safety and preliminary clinical efficacy of an arthroscopically assisted, single-stage injection of a heparin-conjugated fibrin hydrogel (HCFH) for OLT treatment. Methods: Twelve patients with symptomatic OLT underwent arthroscopic debridement, microfracturing, and HCFH injection containing autologous mesenchymal stromal cells (MSCs) and growth factors. Safety was assessed through systematic monitoring of adverse events (graded according to Common Terminology Criteria for Adverse Events criteria), wound healing, and serial laboratory inflammatory markers (leukocytes, erythrocyte sedimentation rate, C-reactive protein) during early and late follow-up. Clinical outcomes were evaluated using the Visual Analog Scale (VAS) and American Orthopedic Foot and Ankle Society score (AOFAS) preoperatively and at 6 and 12 months. Morphological assessment was performed using magnetic resonance imaging (MRI) with the modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system, evaluated independently by two blinded musculoskeletal radiologists. Results: No serious adverse events (Grade III–IV) were observed during the 12-month follow-up. All adverse events were mild (Grade I) and self-limited. A transient postoperative elevation in inflammatory markers was observed, returning to clinically acceptable levels by day 14. Significant improvements were noted in pain (VAS decreased from 6.0 to 2.0) and ankle function (AOFAS increased from 70.0 to 90.6) (p < 0.001). MRI demonstrated progressive morphological improvement, with the MOCART score increasing from 34.16 ± 17.1 at 6 months to 75 ± 5.43 at 12 months (p < 0.001). This increase corresponded with imaging features consistent with tissue maturation over time. The favorable MOCART outcomes observed in this study may be explained by the regenerative properties of heparin-conjugated fibrin hydrogels; however, larger randomized controlled trials with longer follow-up are needed to confirm the durability of the regenerated tissue. Interobserver agreement was substantial to almost perfect for MOCART scoring (κ = 0.68–0.84), with perfect agreement observed for surface assessment, bony defect/overgrowth, and cysts. Conclusions: Within the limitations of this study, single-stage HCFH injection demonstrated an acceptable safety profile and favorable preliminary clinical and radiological outcomes at 12 months. These findings suggest potential regenerative capability; however, controlled studies with larger cohorts and longer follow-up are required to determine comparative efficacy and long-term durability. Full article

Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), poses a serious threat to the global swine industry. Although modified live virus (MLV) vaccines have been widely used in the field for PRRS prevention for decades, the safety and efficacy of these vaccines have long been controversial. Here, we report a rare recombination pattern in China: the emergence of a novel NADC30-like PRRSV strain recombined from two MLV-like strains. Genome comparative analysis reveals that the SCMS2025 isolate has a non-continuous 136-amino acid deletion in the NSP2 protein and shares the highest nucleotide identity of 87.6% with lineage 5 (L5) strains. Phylogenetic analysis showed that SCMS2025 was classified into L1 (NADC30-like) strains based on ORF5 genotyping, whereas it belonged to a single branch between L1 and L5 strains based on the complete genomic sequences. Strikingly, genomic recombination analysis revealed that the newly emerged PRRSV isolate likely resulted from complex recombination events between NADC30-like and two MLV-like strains (RespPRRS MLV and TJbd14-1 MLV-like strains). Furthermore, SCMS2025 infection caused transient overt clinical signs followed by rapid recovery, indicating that the novel PRRSV isolate is a low pathogenic strain. Notably, all SCMS2025-inoculated piglets remained seronegative for PRRSV-specific antibodies throughout the entire 14-day observation period, suggesting a delayed onset of the host humoral immune response. Our study provides evidence for the ongoing evolution of PRRSV through inter lineage recombination and highlights the urgent need for safe and effective vaccines. Full article

Introduction: Chemotherapy-induced thrombocytopenia (CIT) is a common dose-limiting toxicity that disrupts on-time, full-dose chemotherapy, yet no pharmacologic therapy is formally approved. Growing evidence from randomized and late-phase studies with thrombopoietin receptor agonists (TPO-RAs) has renewed interest in targeted supportive care. We evaluated the effectiveness and safety of eltrombopag for CIT in routine clinical practice. Methods: We conducted a small, retrospective, single-arm multicenter cohort study of 31 adults with solid tumors (74.2% stage IV). Given the descriptive, hypothesis-generating nature of this study, no causal inference regarding efficacy can be drawn. Platelet counts and chemotherapy continuity were tracked from baseline through week 12 after eltrombopag initiation. Bleeding, thrombosis, and laboratory safety signals were recorded. Results: The median platelet count increased from 33 × 10⁹/L at baseline to 71 × 10⁹/L at week 1 and 99.5 × 10⁹/L by week 12. Overall, 18/31 patients (58.1%) resumed chemotherapy within 3 weeks, and 15/31 (48.4%) completed planned regimens by week 6. Adverse events were limited to mild, transient elevations in transaminases (n = 3); no major bleeding or thrombotic events occurred. Conclusions: In this real-world multicenter cohort, eltrombopag was associated with rapid platelet recovery and improved chemotherapy deliverability with an acceptable safety profile. The retrospective, single-arm design and the hypothesis-generating nature of these findings preclude definitive conclusions regarding causal efficacy. These observational data highlight the need for prospective controlled trials to characterize the clinical role, optimal dosing, and long-term safety of oral TPO-RAs in CIT. Full article

Background/Objectives: Establishing laparoscopic access remains a critical and complication-prone step in minimally invasive surgery. Previous work has shown that proximal vibroacoustic sensing can identify peritoneal puncture events in porcine cadavers. The present pilot study evaluated whether these findings translate to human anatomy under controlled, ex vivo conditions. Methods: A vibroacoustic sensing prototype was proximally attached to a standard Veress needle during 14 insertions into a fresh human body donor (within 48 h post-mortem). An endoscope was introduced laterally to provide visual ground truth of peritoneal entry. Vibroacoustic signals were recorded at the proximal end of the instrument. Time–frequency analyses, transient excitation detection, and statistical comparisons were performed to assess whether (1) peritoneal puncture can be identified in the vibroacoustic signal, (2) signal phases and dynamics correspond to those previously observed in porcine cadavers, and (3) peritoneal punctures can be statistically differentiated from non-peritoneal events. Results: All 14 peritoneal punctures were identifiable in the vibroacoustic signal under the experimental conditions. Characteristic signal phases previously described in porcine tissue, including transient excitation associated with cavity entry, were consistently reproduced with comparable temporal and spectral profiles. Statistical analyses demonstrated group-level differences between peritoneal and non-peritoneal events, and the peritoneal puncture was the highest-energy event of its insertion in 13 of 14 cases (92.9%). Conclusions: Under the controlled ex vivo conditions of this single-donor pilot study, vibroacoustic sensing was feasible for identifying peritoneal puncture in human tissue and reproduced signal dynamics observed in porcine models. To our knowledge, this is the first demonstration of the proximal vibroacoustic sensing concept on a human body donor and the first cross-species replication of the previously reported puncture phase structure, establishing an important translational stepping stone between animal cadaver studies and in vivo investigations. The study demonstrates feasibility rather than clinical reliability: the single-donor design and the retrospective annotation framework limit generalizability. Prospective validation in living patients, across multiple subjects and operators, is required before clinical deployment. Full article

Long horizontal wells in high-permeability fault-block reservoirs may intersect multiple faults, leading to complex pressure-transient responses, strong parameter coupling in conventional well-test interpretation, inefficient manual history matching, and pronounced non-uniqueness in fault-property identification. To address these challenges, this study proposes a physics-regularized neural inversion framework based on a PINN parameterization and low-weight physics regularization for well-test parameter inversion in long horizontal wells intersecting multiple faults. The proposed method takes the multiple-fault pressure response of a long horizontal well as the target problem. Both the pressure–drawdown curve and the pressure–drawdown derivative curve are used as data constraints. At the same time, parameter scaling and stage-wise training are introduced to jointly invert the reservoir permeability, fault transmissibility coefficient, skin factor, and effective producing length of the horizontal well. Considering that the simplified line-source forward model is not fully consistent with the two-dimensional pressure-diffusion equation and the fault-interface residuals, a physics-loss consistency test is performed to determine safe weighting ranges for the PDE residual and the fault-interface residual. These residuals are then incorporated into the training process as low-weight physics regularization terms to improve the physical plausibility of the inversion results. Results from the base case, different fault types, multiple-fault combinations, noise-robustness tests, ablation experiments, and method comparisons show that the proposed method can stably fit pressure–drawdown and pressure–drawdown derivative curves and effectively identify key well-test parameters in single-fault cases and some multiple-fault cases. In single-fault cases, the order of magnitude of the fault transmissibility coefficient can be identified stably. Reliable inversion performance is obtained for medium- to high-transmissibility faults and some multiple-fault combinations. In contrast, ambiguity remains between sealing faults and strong-baffle faults in multiple low-transmissibility fault combinations. The results further indicate that, under multiple random initializations, the physics-regularized neural inversion framework provides improved inversion stability in the tested synthetic low-transmissibility multiple-fault cases compared with the traditional least-squares method. Therefore, the proposed framework can serve as an intelligent auxiliary tool for well-test parameter inversion and fault-connectivity evaluation in complex fault-block reservoirs. Nevertheless, fine discrimination of low-transmissibility faults and interpretation of highly noisy field data still require joint constraints from geological, seismic, and production-dynamic information. A preliminary reduced field PINN fitting test using the well X falloff event further provides an engineering-scale applicability check for real pressure-transient data, with a pressure NRMSE of 2.457% for the extracted shut-in response. Full article

Background: A novel day–night facial serum regimen combining antioxidants, hydration-enhancing agents, and bioactive compounds has been developed to address skin aging. Objective: The aim is to explore changes in skin aging parameters and assess the safety and tolerability of a day-and-night facial serum combination. Methods: In this single-arm, non-randomized, prospective, open-label study, 30 participants aged 35–55 years applied a day facial serum (DFS) and a night facial serum (NFS) for 8 weeks. Objective assessments included skin texture and depression (Antera 3D^®), elasticity and firmness (Cutometer^®), hydration (Corneometer^®), TEWL (Tewameter^®), melanin index (Mexameter^®), and brightness (Colorimeter^®). Evaluations were performed at baseline, at 1 month and 2 months after treatment start, and at 1 month post-treatment. Results: Thirty participants (Fitzpatrick III–IV) completed the study. Significant improvements in skin texture (p = 0.002) and reduction in skin depression (−22.7%, p < 0.001) were observed after 2 months. Skin firmness increased significantly at 1 month (p < 0.001) and remained elevated post-treatment (p = 0.008). The melanin index decreased at 1 month (p = 0.048), while hydration declined after discontinuation (p = 0.016). TEWL showed a significant overall time effect; however, no Bonferroni-adjusted pairwise comparison versus baseline was significant. No significant changes were observed in elasticity or brightness. Mild transient burning was the most common adverse event. Other reported adverse events included acne, miliaria rubra, oiliness, and mild itching; all were non-serious and did not result in treatment discontinuation. Conclusions: The combined DFS and NFS regimen was well tolerated and was associated with favorable changes in skin texture and firmness. Transient local reactions, particularly mild burning sensation, were commonly reported but did not result in treatment discontinuation. Further controlled studies are warranted to confirm these observations. Full article

Hydrogen is a promising carbon-neutral fuel for future internal combustion engines due to its wide flammability range, high flame speed, and absence of carbon-based emissions. However, its high reactivity significantly increases susceptibility to abnormal combustion phenomena such as knock and pre-ignition, which can compromise engine efficiency, durability, and operational stability. Accurate detection and characterization of knock in hydrogen-fueled spark-ignition engines remain challenging due to the highly transient, broadband, and cycle-dependent nature of abnormal combustion-induced pressure oscillations. Conventional knock indicators based solely on time-domain pressure oscillations or fixed-band frequency analysis are limited in their ability to capture transient resonance behavior and cyclic variability. This study presents an integrated frequency- and time–frequency-domain methodology for knock detection using high-resolution in-cylinder pressure data acquired from a single-cylinder research engine operating under hydrogen port fuel injection (PFI). A discrete Fast Fourier Transform (DFFT) approach applied at stationary points of dynamically windowed pressure signals enables accurate identification of dominant resonance modes while minimizing spectral leakage. A Gaussian-based adaptive windowing strategy is introduced to capture combustion-driven cyclic variations more effectively. Short-Time Fourier Transform (STFT) and sum-based spectral analysis further provide detailed time–frequency localization of transient knock events. The proposed methodology demonstrates a clear separation between normal combustion and knock conditions, enabling reliable cycle-by-cycle identification of abnormal combustion events under varying operating conditions. The experimentally observed resonance frequencies are validated against theoretical predictions using Draper’s acoustic resonance equation, supporting the physical interpretation of knock-induced pressure oscillations. The results demonstrate that the proposed adaptive spectral methodology significantly improves knock detection accuracy compared to conventional indicators and provides a robust framework for advanced knock diagnostics, engine calibration, and combustion control in hydrogen-fueled engines. Full article

Background/Objectives: Persistent dizziness after the apparent resolution of an acute or episodic vestibular disorder remains a frequent and clinically challenging condition. In many patients, symptoms persist despite negative positional testing, absence of spontaneous nystagmus, and preserved high-frequency vestibular responses on video head impulse testing. This discrepancy suggests that persistent dizziness may not always be explained by incomplete recovery of a single peripheral vestibular lesion but may reflect a dissociation between transient/high-frequency vestibular responses and sustained/low-frequency or integrative vestibular processing. The aim of this study was to propose a hypothesis-generating, case-based clinical framework for interpreting this dissociation and its implications for targeted vestibular rehabilitation. Methods: This was a retrospective, hypothesis-generating, case-based clinical study derived from routine specialist neuro-otological practice. Four illustrative cases were selected because they represented distinct patterns of persistent dizziness in which preserved or near-preserved transient vestibular responses coexisted with abnormalities in sustained, otolithic, visual–vestibular, or velocity-storage-dependent processing. All patients underwent detailed clinical history assessment, bedside neuro-otological examination, and multidomain vestibular assessment according to clinical indication. The purpose of the study was not to estimate prevalence, validate diagnostic accuracy, or demonstrate treatment efficacy but to illustrate a physiology-based interpretive framework. Results: The four cases showed different patterns of time-domain dissociation. These included low-frequency integrative dysfunction without clear peripheral lateralization, incompletely compensated unilateral vestibular asymmetry, selective unilateral otolithic loss despite preserved semicircular canal high-frequency responses, and bilateral sustained vestibular hypofunction unmasked by an apparently resolved BPPV-like event. Across cases, persistent symptoms were better explained by the relationship between transient and sustained vestibular domains than by any single test result considered in isolation. Conclusions: Persistent dizziness may arise from different combinations of preserved transient vestibular responses and impaired sustained or integrative vestibular processing. The proposed framework does not introduce new vestibular tests and does not claim to validate a new diagnostic entity. Rather, it organizes established vestibular investigations within a time-domain model that may help identify clinically meaningful dissociations and guide individualized, domain-specific vestibular rehabilitation. Prospective studies with larger samples and external validation are required to determine the diagnostic and therapeutic value of this approach. Full article

Background/Objectives: Transient ischemic attack (TIA) is a neurological emergency associated with a substantial early risk of ischemic stroke, yet its diagnosis remains clinically challenging because objective biomarkers are limited. Glycoprotein VI (GPVI), a platelet collagen receptor involved in platelet activation and thrombus formation, may reflect prothrombotic activity in cerebrovascular ischemia. This study aimed to evaluate the diagnostic assessment and short-term risk stratification value of serum GPVI levels in patients presenting to the emergency department with suspected TIA. Methods: This prospective observational cohort study included 85 adult patients with transient focal neurological symptoms suggestive of TIA. Patients were classified according to the Precise Diagnostic Score (PREDISC), and early stroke risk was assessed using the ABCD2 score. Serum GPVI levels were measured using enzyme-linked immunosorbent assay. Patients were followed for cerebrovascular events at 2 and 7 days. Associations between GPVI levels, clinical scores, and early outcomes were analyzed, and diagnostic performance was assessed using receiver operating characteristic analysis. Results: Serum GPVI levels differed significantly across PREDISC categories and increased from the “TIA unlikely” group to the “TIA very likely” group (p < 0.001). GPVI levels were also higher in patients with ABCD2 scores ≥4 than in those with lower scores (p < 0.001). GPVI showed positive correlations with both PREDISCs (Spearman’s r = 0.682, p = 0.001) and ABCD2 scores (Spearman’s r = 0.469, p = 0.001). All early cerebrovascular events occurred in the high-risk ABCD2 group. Patients who experienced cerebrovascular events had higher baseline GPVI levels, with a small-to-moderate effect size for 2-day outcomes (r = 0.22) and a moderate effect size for 7-day outcomes (r = 0.36). ROC analysis demonstrated discriminative performance for identifying patients classified as “TIA very likely” according to the PREDISC system, with an area under the curve of 0.821 (95% CI: 0.71–0.91). Conclusions: Serum GPVI levels were associated with PREDISC-based clinical TIA likelihood, higher ABCD2-defined risk categories, and early cerebrovascular events in patients with suspected TIA. These findings suggest that GPVI may have a potential complementary role within structured emergency department–based diagnostic assessment and short-term risk stratification frameworks, pending validation in larger independent cohorts. However, because of the exploratory single-center design, modest sample size, limited number of outcome events, and absence of external validation, these findings should be interpreted as hypothesis-generating and require confirmation in larger multicenter studies. Full article

Background: Metastatic renal cell carcinoma (mRCC) remains incurable despite advances with immune checkpoint inhibitors and tyrosine kinase inhibitors. Metabolic interventions, such as the ketogenic diet (KD), may modulate tumor biology and systemic inflammation, yet clinical evidence in mRCC is limited. Objective: To evaluate the feasibility, safety, and tolerability of KD combined with systemic therapy in mRCC patients. Design, Setting, and Participants: CETOREIN was a non-randomized, single-center pilot study enrolling 21 adult mRCC patients initiating systemic therapy. KD was initiated concurrently with treatment for up to 12 months, with follow-up at 1, 3, 6, and 12 months. Intervention: Participants followed a 2:1 KD (≈80% fat, 20% protein + carbohydrates) with dietitian-led counseling, medium-chain triglyceride supplementation, food diaries, and ketonuria monitoring. Outcome Measurements and Statistical Analysis: The primary endpoint was feasibility, defined by diet-related adverse events. Secondary endpoints included adherence, metabolic parameters, and exploratory clinical outcomes (response rate, progression-free survival [PFS], overall survival [OS]). All efficacy-related outcomes were descriptive and exploratory only. Results: Eight patients (40%) completed 12 months on KD, with a mean duration of 7 months. Common diet-related toxicities were diarrhea (55%), weight loss (45%), hypercholesterolemia (40%), and dyspepsia (30%), with no severe events. Early weight loss was modest and transient. Ketonuria correlated with dietary records, confirming adherence. Median PFS was 9.5 months, and median OS was 39 months. Among four patients undergoing cytoreductive nephrectomy, exploratory paired PD-L1 analyses showed decreased expression in three cases; however, these observations are hypothesis-generating only and cannot be attributed to the ketogenic diet. Conclusions: KD is feasible and demonstrated an acceptable tolerability profile in selected mRCC patients, though long-term adherence is challenging. No conclusions regarding antitumor efficacy can be drawn from this small non-randomized pilot study. Future studies should evaluate shorter interventions and optimized dietary protocols in larger randomized trials. Full article

Background: Solar lentigines are common epidermal hyperpigmented macules associated with chronic ultraviolet exposure and photoaging. Objective: To describe a standardized 532 nm green laser protocol for solar lentigines and to place these observations within a narrative review with a structured PubMed/Medline literature search. Methods: Five patients (two women and three men; age range 42–65 years, mean 53.6 years; Fitzpatrick skin phototypes II–III) with solar lentigines underwent treatment with a 532 nm green laser (QuadroStarPRO GREEN, Asclepion) using a standardized, single-session protocol. Outcomes were assessed at the final available follow-up (day 21) by 2 independent dermatologists using a retrospective categorical response classification (complete response/partial response/no response) based on paired baseline and day 21 image documentation only; patient satisfaction was recorded at day 21 on a 0–10 visual analog scale (VAS). A narrative review with a structured PubMed/Medline literature search was conducted to identify clinical studies evaluating 532 nm KTP/green laser devices for lentigines, freckles, and ephelides. Results: All five target lesions were classified as complete response at day 21 (5/5 complete response), with a mean VAS satisfaction score of 8.6/10 (range, 7–10) and no discordance between dermatologists. Mild transient erythema was observed immediately after treatment and improved within the first day; no persistent adverse events, dyschromia, or scarring were observed during the available 21-day follow-up. Conclusions: In this small case series, a single-session millisecond 532 nm green laser protocol was associated with complete-response classification at day 21 in five target lesions. Published clinical studies indicate that outcomes with 532 nm devices vary with device type, pulse structure, and treatment settings; larger comparative studies with objective pigment measures and longer follow-ups are needed. Full article

The precise spatiotemporal monitoring of dopamine is critical for understanding neurotransmission and neurodegenerative pathologies. While traditional electrochemical methods offer excellent temporal resolution, they lack the spatial resolution required to map network-wide dynamic events. To address this, we adapted a wide-field plasmonic electrochemical microscopy (PEM) platform to spatially image localized electrochemical reactions. Specifically, we leveraged the anodic electropolymerization of dopamine into a surface-confined polydopamine nanofilm to enable label-free, pixel-level optical quantification. Bulk solution testing demonstrated highly uniform sensor sensitivity, yielding an estimated single-pixel limit of detection of 14 pM. Furthermore, utilizing a custom injection system, we successfully imaged the real-time localized delivery of micromolar dopamine concentrations and demonstrated qualitative responsiveness of the integrated optical signal to delivered dopamine as a proof-of-concept for the platform. The platform functions as a spatially resolved mass integrator while simultaneously decoupling this chemical signal from transient hydrodynamic mechanical deformations caused by dopamine injection flow. Ultimately, this platform establishes the fundamental methodology required for future high-throughput spatial monitoring of complex neurotransmitter release dynamics across cellular networks. Full article

This paper presents the Goddard RISC-V (GRV) a compact, portable, and highly customizable fault-tolerant 32-bit RISC-V processor, specifically designed for embedded space applications. The design integrates advanced fault-tolerance mechanisms to mitigate arbitrary Single Event Transient (SET) and Single Event Upset (SEU) errors while ensuring data integrity. Importantly, fault tolerance is achieved entirely at the design level, eliminating the need for SEU-hardened semiconductor processes, custom cell libraries, or specialized back-end tools. The implementation prioritizes portability and resource efficiency, enabling compatibility with various FPGA and ASIC technologies. This initiative aims to provide NASA with a suite of portable, modular, and scalable alternatives to proprietary solutions. These solutions are designed for broad adaptability across multiple platforms, such as compact scientific instruments, miniaturized deep-space technologies, CubeSats, control and automation systems, and other applications constrained by low-resource processing environments. Full article

Existing low-dimensional cavity element models developed under the lumped-parameter assumption, which neglect cavity geometric parameters and inertial effects within the cavity, cannot meet the simulation requirements of aircraft-engine secondary air systems (SAS) during the fast transient response processes. To address this gap, this study proposes a modular modeling methodology for a fast transient cavity low-dimensional model. The cavity is partitioned into modules according to the internal flow features during the fast transient response, and the partition ratios are determined by evaluating how different geometric parameters affect these flow characteristics. Using this method, low-dimensional models are constructed for single-port cavities and dual-port cavities under various geometric parameters, and the fast transient depressurization response is investigated. In parallel, corresponding three-dimensional models are established using a validated simulation approach, and three-dimensional computations are performed. Comparison between the low-dimensional and three-dimensional results confirms that the proposed method effectively reproduces the key flow phenomena in the cavity during the fast transient events with credible predictive accuracy. This work optimizes existing low-dimensional simulation algorithms for air systems and provides technical support for studying fast transient responses in aircraft-engine SAS. Full article