Search Results (555)

In this paper, we explore the feasibility of deriving a simple, physically meaningful, and compact formulation for the pressure distribution and lift of an asymmetric delta wing at high angles of attack with an attached shock wave. Such a model would be valuable for rapid engineering analysis. Our approach begins with a compact pressure approximation in the linear regime, which is then extended to the nonlinear case through a geometric transformation and the assumption of functional similarity between linear and nonlinear solutions. This method bridges the solution in the central nonuniform flow region to the exact solutions in the uniform flow regions near the leading-edge shock waves, in a manner analogous to methods used for supersonic starting flow. The model is shown to reproduce existing results for both symmetric and yawed delta wings within an acceptable error margin, providing a compact explicit expression for the normal force coefficient as a weighted average of pressure coefficients from the two uniform flow regions. Additionally, we outline how the approach may be extended to the upper surface, where the uniform flow is described by swept Prandtl–Meyer relations. Full article

Normal shock pressure ratios in equilibrium air for Mach numbers up to 30 and altitudes to 300,000 feet are shown to be correlated by a simple power law which provides an accuracy of ±2%, thereby permitting direct calculation of corresponding enthalpy ratios accurate to ±1% without iteration; a slight change in power-law coefficients extends this capability to Mach 65. Temperature, density, and compressibility may be then found directly from tables for high temperature air. For Mach numbers up to at least 6, a linear approximation for specific heat provides direct solutions for post-shock state variables, while a complementary logarithmic model of the equation of state enables direct solutions for Mach numbers up to about 12. This approach, which provides accuracy within ±3% for all relevant variables in the practical flight corridor of vehicles at these low to moderate hypersonic Mach numbers, should prove useful in design and analysis because the algebraic solutions obtained need neither iteration or interpolation. Full article

In terminal flight trajectory, significant dispersion poses a challenge for accurate localization, as the velocity vector of a supersonic flying object increasingly deviates from the normal vector of the measurement plane under gravitational and aerodynamic effects. Therefore, in this study, an impact point localization method, utilizing a dual-rectangular-ring linear optical microphone array based on apparent shock-wave velocity, was developed. A shock-wave measurement array was developed using a dual rectangular ring composed of linear optical microphone arrays. A time-equivalent model, derived from shock-wave propagation, was introduced to analyze the apparent velocity of the shock-wave within the measurement plane. The time difference in the shock-wave arrivals at the dual rectangular ring, combined with the distances between the inner and outer rectangular rings, was used to calculate the non-uniform apparent shock-wave velocity, thereby enabling the localization of supersonic flying objects. The method’s constraints were examined, and its measurement errors were evaluated. The simulation and experimental results showed that the error was less than 0.5 mm. The proposed novel and cost-effective method for impact point localization aids in the effective dispersion assessment of flying objects. Full article

This study systematically verified the applicability and accuracy of the Probability Density Evolution Method (PDEM) in the probabilistic modeling of the dynamic response of anchored rock slopes under random seismic action through large-scale shaking table model tests. Across 144 sets of non-stationary random ground motions and 7 sets of white noise excitations, key response data such as acceleration, displacement, and changes in anchor axial force were collected. The PDEM was used to model the instantaneous probability density function (PDF) and cumulative distribution function (CDF), which were then compared with the results of normal distribution, Gumbel distribution, and direct sample statistics from multiple dimensions. The results show that the PDEM does not require a preset distribution form and can accurately reproduce the non-Gaussian, multi-modal, and time evolution characteristics of the response; in the reliability assessment of peak responses, its prediction deviation is much smaller than that of traditional parametric models; the three-dimensional probability density evolution cloud map further reveals the law governing the entire process of the response PDF from “narrow and high” in the early stage of the earthquake, “wide and flat” in the main shock stage, to “re-convergence” after the earthquake. The study confirms that the PDEM has significant advantages and engineering application value in the analysis of random seismic responses and the dynamic reliability assessment of anchored slopes. Full article

Background/Objectives: Cross-border retirement migration has become a global trend. However, this population from Hong Kong, with a unique status, offers valuable opportunities for multidimensional empirical research. This paper aims to apply a Stress and Coping Theory–based model to verify the presence of reverse culture shock (RCS) among them and explore how social support and its appraisal are associated with loneliness. It further examines indirect associations involving secondary appraisal within the appraisal structure. Methods: We recruited 210 Hong Kong seniors (aged ≥65) who had relocated to mainland China and had ever returned and surveyed them using validated scales. Results: Robust regression results revealed that higher levels of RCS were associated with higher levels of loneliness. Compared to social support (β = −0.04, p = 0.278), its appraisal had a significant negative association with loneliness (β = −0.09, p < 0.05). Mediation analysis demonstrated a significant indirect association involving social support appraisal, with variation across duration since the last return. Conclusions: With the resumption of normal cross-border travel after COVID-19, RCS is associated with subjective well-being among older returnees. Support appraisal shows a stronger association with loneliness, although this association varies by temporal context. We further propose that within the appraisal structure, secondary appraisal may be implicated in indirect associations linking primary appraisal to emotional outcomes, and that these associations vary by temporal context. Full article

Amid the normalization of flexible employment, labor dispatch, as a form of non-standard employment, has become an important component of China’s precarious labor market (PLM). Based on registration data of labor dispatch firms from 2002 to 2022, this paper analyzes the spatial distribution and evolutionary patterns of China’s PLM, using spatial autocorrelation, kernel density estimation, and Gini coefficient methods. Furthermore, it explores its driving mechanisms through a panel negative binomial regression model. The results show that (i) over the past two decades, China’s PLM has undergone four stages: initiation, acceleration, expansion, and adjustment. (ii) Spatially, it has evolved along the trend of “reinforced clustering with concurrent diffusion,” expanding from first-tier cities in eastern China to second- and third-tier cities in central and western China. (iii) Industrial upgrading, market competition, and the overall level of urban development have significantly promoted the growth of the PLM, while improvements in accessibility, proportion of migrant population, and public service provision have somewhat restrained its expansion. Overall, China’s PLM demonstrates both growth potential and structural vulnerability under institutional constraints and external shocks, offering valuable spatial insights for forging sustainable, high-quality employment and coordinated regional development. Full article

Background/Objectives: Although cross-sectional muscle quality has shown prognostic relevance, the impact of temporal changes in muscle composition in septic shock has not been fully explored. This study aimed to investigate whether deterioration in muscle quality on serial computed tomography (CT) scans is associated with mortality in patients with septic shock. Methods: We conducted a retrospective single-center study using a prospectively collected registry of adult patients with septic shock between May 2016 and May 2022. Patients who underwent CT on the day of emergency department (ED) presentation and had a CT performed more than 180 days earlier were included. Muscle quality maps were generated and segmented based on CT attenuation values into normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and intramuscular adipose tissue area. Differences between the ED and prior CT scans were also calculated. The primary outcome was the 28-day mortality. Results: Among the 768 enrolled patients, the 28-day mortality was 18.0%. Both survivors and non-survivors showed a significantly greater increase in LAMA (20.8 vs. 9.8 cm²) and a greater decrease in NAMA (−26.0 vs. −18.8 cm²). Multivariate analysis identified increased LAMA as an independent risk factor for 28-day mortality (adjusted OR 1.03; 95% CI: 1.01–1.04; p < 0.01). Conclusions: An increase in LAMA on serial CT scans was associated with higher short-term mortality in patients with septic shock, suggesting that temporal degradation of skeletal muscle quality may serve as a potential prognostic marker. Full article

A condition-based maintenance modeling approach is proposed for a multi-state system under competing failures and imperfect repairs. The system experiences three states (normal, defective and failed) over its lifecycle. Two competing failure processes, i.e., natural degradation and external shocks, cause these state changes. If the system becomes defective, an imperfect repair is adopted to restore it to a normal state. Imperfect repairs addressing defects are mathematically characterized. Based on this, two system renewal scenarios and their occurrence probabilities are simulated and derived. The cost of downtime caused by hidden failures is then deduced. A maintenance model of the expected cost rate is constructed, and the optimal inspection period that minimizes the expected cost rate is determined. Finally, a numerical example verifies the correctness and effectiveness of the maintenance model. Full article

Quantitative real-time PCR (qRT-PCR) is a high-reliability, -sensitivity, and -operability technique to quantify gene expression. It is necessary to select stable reference genes for normalization. Water plays important roles in the metabolism, physiology, distribution, and so on, in insects. In this study, the suitability of various reference genes for qRT-PCR analysis was evaluated in different developmental stages of Chilo suppressalis exposed to desiccation or rehydration stress. The ∆Ct method, geNorm, NormFinder, and BestKeeper were used to evaluate the suitability of nine reference genes for normalizing gene expression in the third instar larvae, the fifth instar larvae, male pupae, female pupae, male adults, and female adults under different humidities. The results indicated that 18S rRNA was the most stable reference gene for monitoring gene expression in the third instar larvae, while ACTIN, TUB, UBI, UBI, and EF1 were the optimal genes for the fifth instar larvae, male pupae, female pupae, male adults, and female adults, respectively. The optimal number of reference genes recommended by geNorm analysis indicated that two candidate reference genes were sufficient for data normalization under all experimental conditions tested. To validate these recommendations, the expression profile of the gene encoding heat shock protein 60 (Hsp60) was investigated. Hsp60 transcript levels showed significant differences when normalized to the most stable single reference gene, or combined reference genes, compared with the least stable reference gene. The reference genes identified in the present study will enhance the reliability of gene expression data for C. suppressalis under humidity stress. Full article

Pseudomonas aeruginosa bloodstream infections (PABSIs) are a major clinical challenge due to their association with significant mortality and antimicrobial resistance mechanisms. The COVID-19 pandemic changed antimicrobial practices, intensive care management, and patient risk profiles, potentially influencing the epidemiology and outcomes of PABSIs. In the post-pandemic period, practices were expected to revert to normal. The objective of this scoping review was to identify and summarize reported mortality rates and risk factors for PABSIs in studies published between 2023 and 2025. Literature searches were conducted across PubMed, Web of Science, Embase, and Scopus. Screening was performed in accordance with PRISMA-ScR guidelines. Twenty-two eligible studies were included. Mortality rates varied across the study setting and populations; however, several consistent predictors were consistently identified, including carbapenem exposure, multidrug-resistant Pseudomonas aeruginosa, hematologic disease or malignancy, corticosteroid therapy, sepsis or septic shock, mechanical ventilation, and higher severity-of-illness scores. Few studies have linked molecular mechanisms to patient outcomes, highlighting important gaps in knowledge. Notably, only a small number of studies included the post-pandemic period but did not analyze the data separately. Despite limited available evidence, critically ill and immunocompromised patients remain at greatest risk of death from PABSIs. This review highlights the need for a broader comparative analysis in future. Full article

This study aimed to determine the degree of diversification in exports of fresh/chilled salmon and the level of international competitiveness of Norway, Sweden, Chile, and the United Kingdom over 2020–2024, using the Herfindahl–Hirschman Index (HHI) and the normalized revealed comparative advantage (NRCA). A quantitative, descriptive approach was adopted, drawing on annual Trade Map data for HS subheading 030214. HHI series were constructed by country–destination and NRCA series by country–market, and both were examined through univariate analysis. The findings showed that Norway exhibited low concentration levels and strong, stable advantages in Saudi Arabia, Türkiye, and Russia, whereas Sweden displayed moderate but rising concentration, supported by high advantages in Belgium, the United Kingdom, Germany, and Italy. In contrast, Chile and the United Kingdom recorded persistently high HHI values, with pronounced advantages concentrated in a limited number of markets (Brazil in Chile’s case; France and Chinese Taipei in the UK’s) and intra-product positions or comparative disadvantages in China, the United States, and Mexico. The study concludes that the combination of geographic diversification and positive NRCA enhances export resilience, while extreme specialization increases vulnerability to demand and regulatory shocks. It is recommended that Chile and the United Kingdom further develop diversification strategies toward markets where NRCA is neutral or negative, and that Norway and Sweden consolidate their advantages through investments in sustainability, traceability, and logistics. Further multivariate research incorporating macroeconomic and firm-level variables is also suggested. Full article

Psoriasis is a common inflammatory skin disease with chronic manifestation in which the role of neutrophil extracellular traps (NETs) and alarmins are increasingly recognized as contributors to systemic and cutaneous inflammation. However, the interaction between alarmins and NET-driven immune responses remains poorly defined. The main aim of this study is to define the role of target alarmins (i.e., IL-33 and TSLP) in NETs induction and its subsequent impact on oxidative stress and inflammation in the peripheral blood. In the present study, we recruited active psoriasis patients (n = 56) and control (n = 56) subjects. The frequency of circulating neutrophils, the levels of NET-associated markers (MPO (myeloperoxidase)–DNA complex, CitH3 (citrullinated histone H3), PAD4 (peptidyl arginine deiminase4), NADPH oxidase, and NE (neutrophil elastase)), and alarmin transcripts (IL (interleukin)-33, TSLP (thymic stromal lymphopoietin), S100A7, S100B, HSP (heat shock protein) 60/70 were quantified using flow cytometry, ELISA (Enzyme-linked immunosorbent assay), and qPCR (quantitative polymerase chain reaction), respectively, in each group. The NET formation potential of isolated neutrophils was assessed in the presence or absence of rhIL-33 and rhTSLP by immunocytofluorescence. The effect of rhIL-33- and rhTSLP-primed NETs in augmenting oxidative stress and inflammation was evaluated on peripheral blood mononuclear cells (PBMCs) by ELISA. Significantly higher circulating neutrophils (p < 0.001) and levels of NET-associated markers (i.e., MPO–DNA complex, CitH3, PAD4, NADPH oxidase, and NE) were observed in active psoriasis patients compared to controls. Lesional skin exhibited strong expression of MPO (p < 0.001) compared to normal skin. The alarmins, IL-33 and TSLP, were markedly upregulated in the blood and skin (p < 0.05). The rhIL-33 and rhTSLP treated neutrophils demonstrated enhanced NETosis in patients (p < 0.001). Increased expression of inflammatory cytokines and oxidative stress markers were reported in PBMCs when incubated with rhIL-33- and rhTSLP-primed NETs. Taken together, our investigation demonstrated the novel mechanism wherein the alarmins IL-33 and TSLP exacerbate NET formation that may drive enhanced inflammation and oxidative stress in psoriasis. Full article

Heat shock protein (HSP) gene families are known to be expressed preferentially over normal cellular proteins when poultry cells are exposed to environmental stressors. Bordetella avium infection leads to bordetellosis, which is characterized by severe inflammation of the tracheal epithelium, representing a severe stressor for the infected turkey poult. The purpose of this experiment was to examine the expression of HSP60 and HSP70 in the tracheae of B. avium-challenged poults. Tracheae were dissected from five poults per treatment at 7, 11, 14, and 21 days of age, and snap-frozen rings were examined immunohistochemically for the presence of HSP60 and HSP70 using HSP60 and HSP70 monoclonal antibodies (MABs). Infected poults expressed HSP60 predominantly on the apical surface of ciliated epithelial cells and weakly near the nucleus, and HSP70 was expressed only in the cytoplasm. Early in the development of bordetellosis, infected poults expressed more HSP60 and HSP70 than control poults of the same age, but at 14 days after infection, infected birds showed significantly decreased HSP60 proteins, which was associated with loss of tracheal epithelium. With loss of tracheal epithelium, the expression of HSP70 decreased at 11 days in the infected poults, and by day 21, very low levels of the proteins were observed in the infected poults compared to control poults with intact tracheal epithelium. It was concluded that decreased expression of HSP60 was indicative of HSP60 proteins becoming antigenic targets for the host’s immune system since immunologically targeted B. avium cells express GroEL (highly conserved HSP60 family equivalent) and DnaK (highly conserved HSP70 equivalent). The potential targeting of host and pathogen HSP60 by the innate immune system could feasibly facilitate loss of tracheal epithelium during the development of bordetellosis. Full article

Vascular Smooth Muscle Cells (VSMC) dysfunction is a major contributor to Type 1 diabetes (T1D)-associated vascular complications. Ca²⁺ is a key messenger responsible for maintaining VSMC tone and function, and alterations in its cytosolic levels are central to diabetes-related vasculopathy. Heat Shock Protein 70 (HSP70), a multifaceted chaperone present intracellularly (iHSP70), regulates vascular reactivity by supporting Ca²⁺ handling, and extracellularly (eHSP70) activates immune signaling. Disruption of eHSP70/iHSP70 balance has been implicated in T1D-associated VSMC dysfunction. Curcumin, a phytochemical found in turmeric, is an emerging therapeutic adjuvant for treating a wide range of pathologies, including diabetes. However, whether curcumin modulates Ca²⁺ dynamics and HSP70 expression, thereby improving VSMC function, in diabetic aorta remains unclear. To investigate this, Streptozotocin-induced diabetic rats (i.p. 65 mg/kg) were treated with curcumin (300 mg/kg) for 28 days. Vascular function was evaluated using wire myography to assess changes in biphasic contraction curve and Ca²⁺ dynamics, while HSP70 was quantified using Western blotting and ELISA. Structural alterations were analyzed by assessing collagen and elastin using Picrosirius staining and fluorescence microscopy. Chronic curcumin treatment improved vascular function by normalizing Ca²⁺ mishandling, restoring the eHSP70/iHSP70 ratio, reducing hypercontractility, and mitigating arterial structural alterations. These findings indicate that curcumin could potentially ameliorate diabetes-related VSMC dysfunction by restoring Ca²⁺ homeostasis and modulating HSP70. Full article

Objectives: We aim to investigate the relationship between body weight and the risk of cardiovascular events in heart failure patients with diabetes. Methods: We therefore conducted a retrospective analysis of HF patients with T2D using the Nationwide Readmissions Database (NRD) from 2016 to 2022. Patients were stratified by BMI classes: underweight, normal weight, overweight, and obesity classes I–III. The primary outcome was in-hospital mortality. Secondary outcomes included 1-year mortality and readmission for heart failure. Results: A total of 26,199 patients with BMI data were included in the analysis. Underweight patients had the highest risk of in-hospital mortality [aOR = 1.80 (95% CI: 1.16–2.80)] and cardiogenic shock [aOR = 2.13 (95% CI: 1.26–3.59)]. In contrast, obesity classes I–III were associated with significantly lower odds of those events. One-year mortality rates did not differ significantly across BMI groups. However, obesity classes II and III were associated with a lower adjusted risk of HF readmission [aHR = 0.71 (95% CI: 0.50–0.99); aHR = 0.68 (95% CI: 0.49–0.96), respectively]. Conclusions: In patients with T2D and HF, an obesity paradox exists whereby patients with obesity have a lower risk of in-hospital mortality and cardiogenic shock. Further, obesity classes II-III are associated with a lower risk of 1-year readmission for HF. Full article