Search Results (567)

Introduction: Currently, REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) is an emerging technique for resuscitation in patients presenting severe pathology in hemodynamic shock refractory to conventional treatments. The REBOA technique consists of inserting a balloon through the femoral artery to temporarily occlude the aorta and thus control massive bleeding and improve perfusion of vital organs in critical situations such as hemorrhagic shock. Although it is not a definitive technique, its use buys time before the implementation of a definitive treatment when possible. This makes REBOA an ideal technique for the philosophy of out-of-hospital emergency services and more particularly in the HEMS (Helicopter Emergency Medical Service) environment. On the other hand, REBOA has been postulated as one of the basic pillars in the resuscitation of severe trauma patients with hemorrhagic shock and of the doctrine of damage-control resuscitation in non-compressible torso and lower limb hemorrhage. Objective: To evaluate the potential feasibility of REBOA implementation in patients attended by HEMS teams in Castilla-La Mancha, Spain. Method: A retrospective observational study was conducted analyzing medical and nursing reports from HEMS units between 1 January and 31 December 2023. A statistical study of the variables collected was carried out using statistical techniques appropriate to the pre-specified study variables. A descriptive analysis of the population was performed. Frequency results are expressed in absolute terms, as percentages and confidence intervals. Continuous variables are expressed as mean (SD) and median (range) according to normality test (Kolmogorov–Smirnov test). For the study of the relationship between the different variables, Chi-square or Analysis of Variance is used if they are parametric. Descriptive and inferential statistics were performed using SPSS v24. Results: A total of 103 patients (72.81% men, mean age 57.7 years) were identified as potential REBOA candidates. On arrival of the emergency services the mean SI (shock index) of the patients was 1.36 (SD +/− 0.380). On arrival at the hospital, the mean SI was 1.25 (SD +/− 0.601). Of the series, 57 (55.33%) patients suffered cardiorespiratory arrest (CRA) at some point during pre-hospital care. Of the total number of patients, 38 were patients presenting severe trauma criteria (characterized by life-threatening injuries, with RTS score ≤ 11, shock index > 0.9, or ISS ≥ 16, indicating severe physiological or anatomical alterations), of which 26 (68.4%) did not go into CRA, while 12 (31.6%) did. Of the total number of patients, 65 (63.1%) did not meet severe trauma criteria, but did present medical criteria for REBOA placement, of which 55 (53.4%) were patients who at some point during attendance presented CRA. Although the shock index showed a slight decrease after healthcare without statistical significance or relevant correlation, a highly significant association was observed between severe trauma and cardiorespiratory arrest (p < 0.001). Conclusions: It could be affirmed that it may have been feasible to implement REBOA in 4.47% (103) of the patients attended by the HEMS healthcare team of Castilla-La Mancha. This could help to reduce the morbimortality and mortality of critical patients in medical helicopters. More studies are needed to corroborate this assertion. Full article

The rapid evaporation of liquid droplets across a normal shock wave is a phenomenon of critical importance in advanced propulsion and clean energy systems, such as NH₃ supersonic separation. The conventional Spalding d²-law is commonly used to model such phenomena, but it is not suitable for predicting the complete vaporization of sub-micron droplets, particularly as evaporation approaches the free-molecular regime. To address this issue, this paper introduces a novel time-dependent one-dimensional CFD model, which is used to analyze the shock structure, the non-equilibrium heat and mass transfer between the liquid and gas phases, and the evolution of the droplets’ size through the shock. The model describes the evaporation of NH₃ sub-micron droplet sprays across a stationary normal shock for various fractions of the liquid phase. The Gyarmathy evaporation model is utilized to accurately account for the transition from diffusion-governed to free-molecular regimes, alongside a new two-phase Rankine–Hugoniot shock jump formulation. The study reveals the influence of a steady normal shock on the physical structure of a droplet-laden flow, including the existence of an initial droplet size swelling through the shock, and quantifies the subsequent complete evaporation of the suspended droplets. The maximum swelling throughout the shock is up to 17%, which corresponds to the case with 8% liquid phase mass fraction in the flow. The model provides acceptable accuracy in calculating the two-phase parameters in high-speed flows and can be extended for modeling more complex, multidimensional detonation and propulsion systems. Full article

Objectives: This study aims to evaluate whether changes in perfusion index (PI) after the first deflation of the blood pressure cuff during remote ischemic conditioning (RIC) are associated with passive leg raising (PLR)-induced changes in stroke volume. In addition, we compared PI changes after cuff deflation during RIC between critically ill patients and healthy controls. Methods: This prospective, single-center study was conducted in a mixed ICU at a tertiary teaching hospital. Patients aged >18 years admitted to the ICU, monitored using calibrated pulse contour analysis, and scheduled for a PLR test as decided by the attending physicians were included. The PI was measured after blood pressure cuff deflations during RIC (3 cycles of brachial cuff inflation to 200 mmHg for 5 min, followed by instantaneous deflation to 0 mmHg for another 5 min) in the supine position after PLR. Preload responsiveness was defined as a ≥10% increase in the stroke volume index (SVI) during PLR. Data were compared with a healthy control group. Results: Thirty-three patients were included (median age 62; 45% in shock; 55% mechanically ventilated). When comparing critically ill patients with healthy volunteers, the maximum PI change (dPImax) and the time to reach it were higher in critically ill patients after the first and second cuff deflations (p < 0.05). However, after the third deflation, the difference was no longer significant. Following the first deflation, dPImax was significantly correlated with SVI changes during PLR (r = 0.63, p < 0.001). After the cuff was first deflated, we detected a PI cutoff with a positive SVI response (≥10%) during PLR, with a sensitivity of 64% and a specificity of 94% (area under the receiver operating characteristic curve 0.752; 95% CI, 0.564–0.940; p = 0.008). Conclusions: The maximum change in perfusion index following brachial blood pressure cuff deflation after five minutes of inflation may serve as a promising noninvasive bedside indicator of preload responsiveness in critically ill patients. Additionally, the observed normalization of PI kinetics during RIC suggests possible acute modulation of vascular reactivity, though further research is needed to confirm an association between PI changes and endothelial function. Full article

Background: The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for hemorrhagic shock in the torso has become increasingly common as a bridge to definitive hemostasis. Hydrogen molecules, distributed throughout the bloodstream, alleviate ischemic injury but cannot reach ischemic organs during REBOA use. This study investigates whether intra-aortic irrigation with hydrogen-dissolved saline under REBOA use delivers hydrogen to the intestine in a swine hemorrhagic shock model. Methods: We induced volume-regulated hemorrhagic shock in a 40 kg female swine. Following this, hydrogen-dissolved saline irrigation was initiated through an intra-aortic catheter positioned distal to the REBOA balloon. Hydrogen concentration in the portal vein was determined in four models: controlled hemorrhagic shock with full REBOA inflation during the standard occlusion time, uncontrolled hemorrhagic shock with liver injury and full REBOA inflation during the extended occlusion time, uncontrolled hemorrhagic shock with liver injury and partial REBOA inflation during the extended occlusion time, and as the control model, controlled hemorrhagic shock with full REBOA inflation during the standard occlusion time with normal saline irrigation without hydrogen. Results: Hydrogen concentration in the portal vein was found to be 0.224 mg/L (13.998%) in the controlled hemorrhagic shock model with full REBOA inflation, 0.049 mg/L (3.063%) in the uncontrolled hemorrhagic shock model with liver injury and full REBOA inflation, 0.018 mg/L (1.125%) in the uncontrolled hemorrhagic shock model with liver injury and partial REBOA inflation, and 0.002 mg/L (0.015%) in the control model. These results demonstrate the presence of hydrogen in the portal vein under different REBOA applications. Conclusions: Increased hydrogen concentration in the portal vein indicated that hydrogen was delivered to the intestine. These findings suggest an approach for drug administration during REBOA use. However, further investigations are required to establish its application in clinical settings. Full article

Background/Objectives: Pulmonary embolism (PE) remains a significant cause of cardiovascular mortality, with risk stratification being critical for optimizing treatment decisions. Heart rate variability (HRV), a measure of autonomic nervous system function, had been explored as a prognostic index in various cardiovascular conditions, yet has received limited investigation regarding PE prognosis. Our objective was to evaluate the prognostic value of ultra-short HRV indices, obtained at the emergency department (ED), in patients presenting with PE. Methods: A retrospective cohort study, conducted at Rambam Health Care Campus, Haifa, Israel. All eligible patients diagnosed with acute PE at the ED, between the years 2010 and 2012 were included. Further, a subgroup analysis was performed to differentiate between oncological (n = 118) and non-oncological (n = 115) patient populations. Ten-seconds electrocardiogram was used to compute ultra-short HRV indices, specifically SDNN (standard deviation of normal-to-normal RR intervals) and RMSSD (root mean square of successive differences). Multivariate logistic regression models were created to assess HRV’s independent predictive value for 30-day and 90-day mortality. In addition, a survival analysis was carried out utilizing Cox regression and Kaplan-Meier curves. Results: 233 patients (42% male; age 65 ± 17) were included in the analysis. Ultra-short HRV indices did not significantly correlate with short-term mortality. However, in non-oncological patients (n = 115), multivariate analysis demonstrated that higher SDNN (as a continuous variable), was independently associated with increased 90-day mortality (AOR 1.018, 95% CI 1.000–1.037; p = 0.044). In contrast, HRV showed no predictive value for mortality in oncological patients. In both the entire cohort and the non-oncological sub-group, Kaplan-Meier plots established statistically significant differences, with lower HRV indices correlating with worse survival. This finding is paradoxical. The issue of context-dependent HRV (i.e., based on ECG obtained during rapid shallow breathing, which reduces HRV on the one hand, but is possibly adaptive during an acute PE, to increase oxygen supply and prevent shock in the short run, on the other hand), may explain these findings. Conclusions: Ultra-short HRV shows some promise in short term risk stratification of non-oncological PE patients. As for oncological patients, HRV was not found to have short term prognostic relevance. Full article

This study aimed to jointly characterize destination diversification and revealed competitiveness in the international shrimp and prawn trade of Ecuador, India, Vietnam, and Indonesia during 2020–2024. A quantitative, descriptive–comparative approach was applied using annual free-on-board values at the exporter–destination level obtained from Trade Map (International Trade Centre). Destination diversification was proxied by the Herfindahl–Hirschman Index, while market-level competitiveness was measured through the Normalized Revealed Comparative Advantage index. Results show that Ecuador expanded exports while maintaining persistently high destination concentration. India exhibited broad revealed comparative advantage across multiple markets, yet remained highly concentrated, with episodes of deconcentration that were not sustained. Vietnam recorded relative stagnation, moderate concentration, and heterogeneous competitiveness across destinations. Indonesia experienced contraction with extremely high concentration, characterized by a pronounced advantage in the United States alongside disadvantages in alternative markets. Overall, a positive NRCA did not necessarily coincide with a low HHI, and configurations in which revealed advantage is concentrated in a small set of anchor markets are associated with higher exposure and may entail more limited reorientation options under shocks. Full article

Background and Objectives: Septic shock is marked by profound circulatory and cellular dysfunction, with mortality rates of 25–40% despite guideline-based resuscitation. Normalization of macrohemodynamic variables often fails to restore tissue perfusion, a concept known as hemodynamic incoherence. Persistent microcirculatory dysfunction is associated with organ failure and poor outcomes, underscoring the limitations of systemic monitoring alone. This focused narrative review synthesizes current evidence on microcirculatory monitoring in septic shock, with emphasis on bedside and emerging optical technologies, and evaluates their role as adjuncts to traditional hemodynamic assessment for perfusion-targeted resuscitation. Materials and Methods: A concept-driven search of PubMed/MEDLINE (January 2015 to January 2026) was performed, incorporating MeSH and free-text terms for septic shock, microcirculation, hemodynamic coherence, and monitoring modalities. Foundational pre-2015 studies were included for context. Articles were screened using predefined inclusion/exclusion criteria to minimize bias, with thematic qualitative synthesis. A PRISMA-inspired flow diagram was used to summarize the study selection process. Results: Microcirculatory alterations in septic shock include reduced functional capillary density, perfusion heterogeneity, and impaired oxygen extraction, persisting despite macrohemodynamic correction. Bedside markers, such as capillary refill time (CRT) and mottling, track microvascular recovery more closely than lactate. When used to guide resuscitation, CRT-based strategies show a non-significant mortality trend in randomized evaluation, with later studies reporting benefit in composite clinical outcomes. Optical technologies offer non-invasive insights: photoplethysmography (PPG) and perfusion index (PI) show prognostic value and early detection of incoherence; automated CRT (aCRT) enhances reproducibility; advanced modalities, such as laser speckle contrast imaging (LSCI), near-infrared spectroscopy (NIRS), and sublingual videomicroscopy, provide detailed physiological data but face standardization challenges. Recent interventional evidence, including peripheral perfusion-targeted RCTs, supports improved outcomes, though large-scale trials remain limited. Conclusions: Microcirculatory monitoring provides complementary, physiologically relevant information to macrohemodynamic assessment in septic shock. Emerging bedside tools, such as PI and aCRT, are poised for routine use, while multimodal integration may enable personalized management. Future research should prioritize standardization, AI-driven analysis, and randomized trials to confirm outcome benefits. Full article

Hyperthermia (HT) is a promising adjunct to conventional cancer therapies such as chemotherapy and radiotherapy (RT). It offers several advantages, including low toxicity to normal tissues, limited tumor resistance, and synergistic therapeutic effects. HT enhances treatment efficacy by inhibiting DNA repair mechanisms, increasing tumor membrane permeability for improved drug uptake, and improving oxygenation to reduce hypoxia-induced resistance. HT also promotes cancer cell death by inducing oxidative stress, leading to mitochondrial dysfunction, caspase activation, and PARP cleavage. It causes G2/M cell cycle arrest and damages tumor vasculature. Additionally, HT downregulates proangiogenic and invasive factors such as TGF-β1, VEGF, and MMP-2/9, contributing to reduced tumor progression. Combining HT with natural compounds like propolis and flavonoids further improves therapeutic outcomes. These natural agents are accessible, cost-effective, and exhibit multi-targeted anticancer activity. In synergy with HT, they enhance reactive oxygen species (ROS) generation, suppress heat shock proteins, modulate the tumor microenvironment (TME), and activate immune responses. They may also reduce the side effects of conventional therapies and support tissue regeneration. Overall, HT, especially in combination with natural compounds, offers a multifaceted and effective approach to cancer therapy. Full article

This study presents the high-speed visualization of the detonation wave structure in a small-scale hydrogen–oxygen rotating detonation combustor. A 68 mm Rotating Detonation Combustor was modified with a quartz-glass ring, such that radial optical access into the annular detonation chamber was realized. The optical access window covers approximately the first 22 mm of the detonation chamber. The modified experiment was hot-fire tested with the propellant combination gaseous hydrogen–oxygen. Simultaneous high-speed imaging from the back-end of the chamber and normal to the chamber axis allows a thorough investigation of the detonation wave characteristics. Both high-speed cameras were operated at 180,000 frames per second in order to resolve and capture the detonation waves. The downstream camera was used in order to investigate the number of waves and the spinning direction. A stable regime of three co-rotating waves was observed. The wave speed achieved 71% of the theoretical CJ-velocity. The second camera recorded the passing detonation waves through a quartz ring via OH* emissions. From the post-processed OH* images, a better understanding of the detonation wave structure, including the filling height of the fresh gas mixture as well as the approximate angles of the detonation and the shock wave, could be gained. The obtained height of the detonation wave is about 11–12 mm or 6–7 detonation cell sizes for the given setup and experimental conditions. Full article

This study investigates the functional role of OsHSBP1, a heat shock factor-binding protein, in regulating abiotic stress tolerance in rice, with the aim of enhancing climate resilience in the elite indica cultivar Bacthom 7 (BT7). Using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9) genome editing, we generated transgene-free homozygous knockout lines targeting OsHSBP1 and evaluated their physiological, biochemical, and agronomic responses under heat stress. Mutant lines exhibited markedly improved tolerance to both stresses, with survival rates reaching 43–46% under heat stress, compared to near-zero in wildtype plants. Enhanced tolerance was associated with significantly increased catalase and peroxidase activities and reduced oxidative damage, including lower malondialdehyde content and decreased superoxide accumulation. Despite these stress-related advantages, the knockout lines showed minimal differences in key agronomic traits under normal growing conditions, with comparable plant height, tillering ability, grain yield, and amylose content relative to the wildtype. These results demonstrate that OsHSBP1 functions as a negative regulator of abiotic stress tolerance in rice, and its knockout enhances resilience without compromising yield potential. The study highlights OsHSBP1 as a promising target for precision breeding of climate-resilient rice cultivars. Full article

Chronic subdural hematoma (CSDH) in frail older adults is increasingly recognized as a sentinel event, with mortality often driven by medical complications rather than neurosurgical factors. We report a failure-to-rescue case in which rapid postoperative deterioration occurred after burr-hole drainage for bilateral CSDH in a frail older adult with diabetes. A clinical picture consistent with sepsis was suspected, and a gastrointestinal source was considered, but the infectious focus could not be confirmed due to limited diagnostic work-up. On admission, chest-computed tomography showed mild right lower-lobe pneumonia, and incidental transverse colonic dilatation was also visible. Burr-hole drainage was uneventful and oxygenation rapidly normalized on room air. On postoperative day (POD) 3, the patient developed a high fever (39 °C), rising C-reactive protein (CRP; 14 mg/dL), abrupt leukopenia (15,300 → 3300/µL), and, several hours later, profuse watery diarrhea. At that time, an evaluation for an infectious source and escalation of therapy (e.g., blood cultures, serum lactate, and abdominal imaging) were not performed. In the early hours of POD 4, he suffered sudden desaturation, shock, and cardiac arrest, and died despite resuscitation. A portable radiograph after intubation showed no new diffuse pulmonary infiltrates but marked colonic gas distension. This case highlights the need to reassess diagnostic framing when discordant postoperative “red flags” emerge and proposes practical triggers for early sepsis evaluation and escalation—prioritizing early recognition and timely rescue rather than a definitive determination of the cause of death—in high-risk CSDH patients. Full article

This paper presents an experimental investigation of unsteady phenomena in shock wave/boundary-layer interaction on natural laminar flow airfoils at transonic speeds. Two airfoils of different relative thickness were studied over a Mach number range of M = 0.62–0.72 using high-speed schlieren visualization, unsteady pressure transducers, and Particle Image Velocimetry (PIV). Two distinct self-sustained periodical oscillation modes were identified. The first mode is a low-frequency oscillation analogous to classical turbulent buffet. The second modes are higher-frequency phenomena linked to oscillations of the laminar separation bubble. A key finding is a novel periodical oscillation regime, which accompanies the first/second mode, and represents laminar-turbulent transition point detaches from the normal shock wave, generating a new shock wave. The results show that the domiN/At mode and its characteristics depend strongly on the airfoil geometry, Mach number, and angle of attack, indicating a more complex transonic buffet behaviour in the presence of extensive laminar flow. Full article

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