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This study investigates the dynamic behavior of a three-body tethered satellite system with a flexible tether, focusing on a scenario in which a payload is transported along the tether connecting two satellites. Traditional models use rigid tethers, limiting the analysis of complex dynamics such as tether deformation, slack, and rebound. To address these limitations, we employed the absolute nodal coordinate formulation (ANCF) to model the flexibility of the tether. We derived nonlinear equations of motion using Lagrange’s equation and solved them using the Newmark time integration method to obtain the dynamic responses of the satellite system. Our findings revealed that the Coriolis effect caused significant deviations in the payload trajectory as its mass and speed increased, leading to greater tether deformation and slack, and potential system destabilization. Additionally, axial force fluctuations in the tether varied notably as the payload moved, transitioning between tensile and compressive states. This study provides a more accurate representation of three-body tethered satellite systems by incorporating tether flexibility, offering valuable insights into the dynamic behavior and stability of the system.

This study investigates the mechanism behind the cavitation-induced noise in an automotive heater core and proposes a structural solution to eliminate it. Abnormal noise during cold-start conditions in a compact passenger vehicle was traced to cavitation in the heater core of the heating, ventilation, and air conditioning (HVAC) system. Controlled bench tests, in-vehicle measurements, and computational fluid dynamics (CFD) simulations were conducted to analyze flow behavior and identify the precise location and conditions for cavitation onset. Results showed that high flow rates and low coolant pressure generated vapor bubbles near the junction of the upper tank and outlet pipe, producing distinctive impulsive noise and vibration signals. Flow visualization using a transparent pipe and accelerometer data confirmed cavitation collapse at this location. CFD analysis indicated that the original geometry created a high-velocity, low-pressure region conducive to cavitation. A redesigned outlet with a tapered transition and larger diameter significantly improved flow conditions, raising the cavitation index and eliminating cavitation events. Experimental validation confirmed the effectiveness of the modified design. These findings contribute to improving the acoustic performance and reliability of automotive HVAC systems and offer broader insights into cavitation mitigation in fluid systems.

This study presents a dynamic model of a passenger vehicle and analyzes its dynamic characteristics and responses. A dynamic vehicle model with seven degrees of freedom was established to analyze the behavior of a driving vehicle. The vehicle model had three degrees of freedom for the sprung mass’s motion and four degrees for the unsprung masses. For this model, the equations of motion were derived using Lagrange’s equation. To verify the model, the suspension deformations computed using the model were compared with those measured through three actual vehicle driving tests: the slalom, double lane change, and step steer tests. Furthermore, we investigated the effects of suspension stiffness, suspension damping, and anti-roll bar torsional stiffness on the dynamic characteristics and responses of the vehicle model. This study presented a new full-car model that can analyze a turning vehicle’s behavior in response to changes in the steering angle input. The developed dynamic vehicle model may help vehicle designers predict the dynamic responses of a vehicle through simulation without performing a driving test.

Introduction: Metabolism-associated fatty liver disease (MAFLD) is a global health concern because of its association with obesity, insulin resistance, and other metabolic abnormalities. Methylsulfonylmethane (MSM), an organic sulfur compound found in various plants and animals, exerts antioxidant and anti-inflammatory effects. Here, we aimed to assess the anti-obesity activity and autophagy-related mechanisms of Methylsulfonylmethane. Method: Human hepatoma (HepG2) cells treated with palmitic acid (PA) were used to examine the effects of MSM on autophagic clearance. To evaluate the anti-obesity effect of MSM, male C57/BL6 mice were fed a high-fat diet (HFD; 60% calories) and administered an oral dose of MSM (200 or 400 mg/kg/day). Moreover, we investigated the AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin complex 1 (mTORC1)/UNC-51-like autophagy-activating kinase 1 (ULK1) signaling pathway to further determine the underlying action mechanism of MSM. Results: Methylsulfonylmethane treatment significantly mitigated PA-induced protein aggregation in human hepatoma HepG2 cells. Additionally, Methylsulfonylmethane treatment reversed the PA-induced impairment of autophagic flux. Methylsulfonylmethane also enhanced the insulin sensitivity and significantly suppressed the HFD-induced obesity and hepatic steatosis in mice. Western blotting revealed that Methylsulfonylmethane improved ubiquitinated protein clearance in HFD-induced fatty liver. Remarkably, Methylsulfonylmethane promoted the activation of AMPK and ULK1 and inhibited mTOR activity. Conclusion: Our study suggests that MSM ameliorates hepatic steatosis by enhancing the autophagic flux via an AMPK/mTOR/ULK1-dependent signaling pathway. These findings highlight the therapeutic potential of MSM for obesity-related MAFLD treatment.

This article investigates the source of booming noise emanating from the tailgate of an electric sport utility vehicle (SUV), along with proposed strategies to mitigate it. This annoying low-frequency booming noise, which significantly impacts interior sound quality, is less perceptible in conventional internal combustion engine vehicles. However, this noise is more readily detected in electric SUVs, highlighting the necessity for focused measures to reduce it. This study involved the measurement of booming noises during on-road vehicle tests to pinpoint their origins. Additionally, ODSs were extracted from the tailgate vibration signals to gain insight into its dynamic behavior. Modal tests were conducted on the tailgate to determine its dynamic characteristics and compared with driving test results to reveal the mechanism responsible for tailgate-induced booming noise. It was established that such noise is primarily due to the tailgate modes, resulting from a combination of rigid body motion in the fore-aft direction and deformation in the central section of the panel. An analytical model of the tailgate was developed using commercial finite-element analysis software to propose measures for reducing booming noise. Experimental findings validated this model’s accuracy. Structural enhancements were implemented to enhance the panel stiffness and improve the connection between the vehicle and tailgate via bushings to reduce the booming noise resulting from tailgate motion. Under random force inputs, the analytical results demonstrated a 13.8% reduction in maximum deformation in the tailgate model in the improved structural configuration with increased panel stiffness. This study identifies the mechanism generating booming noise, establishes a practical and simple dynamic model, and proposes improvement measures aimed at reducing the booming noise.

Molecular mechanisms underlying the decreased number of macrophages and T cells in the arteries of cholesterol-fed-rabbits following dexamethasone administration are unknown. We investigated the possibility that dexamethasone could affect activation of monocytic cells induced by oxygenated derivatives of cholesterol (oxysterols) using THP-1 monocyte/macrophage cells. 27-Hydroxycholesterol (27OHChol), an oxysterol elevated with hypercholesterolemia, enhanced production of CCL2, known as MCP1, chemokine from monocytes/macrophages and migration of the monocytic cells, but the CCL2 production and the cell migration were reduced by treatment with dexamethasone. Dexamethasone inhibited superproduction of CCL2 induced by 27OHChol plus LPS and attenuated transcription of matrix metalloproteinase 9 as well as secretion of its active gene product induced by 27OHChol. The drug downregulated cellular and surface levels of CD14 and blocked release of soluble CD14 without altering transcription of the gene. Dexamethasone also inhibited expression and phosphorylation of the NF-κB p65 subunit enhanced by 27OHChol. Collectively, these results indicate that dexamethasone inhibits activation of monocytes/macrophages in response to 27OHChol, thereby leading to decreased migration of inflammatory cells in milieu rich in oxygenated derivatives of cholesterol.

Ascending aortic mural thrombus (AMT) is an exceptionally rare condition. Diagnosis is often difficult because non-ECG-gated contrast-enhanced CT is susceptible to motion artifacts, and the distal ascending aorta can sometimes be challenging to evaluate using transesophageal echocardiography. A standardized surgical strategy for ascending AMT has not been established. A 61-year-old man presented with transient left hemiplegia caused by embolic stroke. A non-ECG-gated contrast-enhanced CT scan revealed a thrombus-like structure in the ascending aorta; however, ECG-gated contrast-enhanced CT clearly demonstrated a thin-stalked and mobile thrombus, prompting urgent surgery. Cardiopulmonary bypass (CPB) was established using bilateral axillary artery cannulation and bicaval venous drainage. To minimize the risk of cerebral embolization during CPB initiation, the left common carotid artery (LCCA) was temporarily clamped under near-infrared spectroscopy monitoring. After cooling to 26°C, circulatory arrest with brachiocephalic artery and LCCA clamping and unilateral selective cerebral perfusion (uSCP) was performed. A highly mobile thrombus-like mass located just proximal to the brachiocephalic artery was excised with an adequate margin, followed by partial arch replacement with reconstruction of two arch branches. The postoperative course was uneventful, and pathology confirmed atherosclerosis with fresh thrombi and early organization. ECG-gated contrast enhanced CT is essential for accurate diagnosis of ascending AMT, particularly when small lesions mimic motion artifacts. The combination of bilateral axillary cannulation, LCCA occlusion, and a modified brain isolation strategy using uSCP may provide a safe and effective approach for surgical treatment of ascending AMT without neurological complications.

Younger patients with acute aortic dissection (AAD) are thought to present with distinct anatomical and hemodynamic features compared with older patients. This study evaluated the association between age, dissection extent, and false-lumen flow characteristics in AAD. We retrospectively analyzed 400 consecutive patients with radiologically confirmed AAD from April 2014 to April 2024, categorizing them into a younger group (<76 years,  = 229) and an older group (≥76 years,  = 171). The distribution of Stanford type A vs. B dissections was similar between groups. However, younger patients more frequently demonstrated DeBakey type I dissection, whereas older patients more commonly had type II. Regarding false-lumen morphology, younger patients showed a higher prevalence of communicating false lumen, while non-communicating patterns predominated in the elderly. Although overall sex distribution of false-lumen types was not significantly different, younger males were more prevalent within each subtype. Preoperative malperfusion occurred more often in younger patients, whereas 30-day mortality did not differ significantly between age groups. Younger AAD patients typically exhibit more extensive dissection and patent false-lumen flow, while older patients more often present with localized dissection and thrombosed false lumen. These age-related distinctions may reflect progressive aortic wall stiffening and should be considered in clinical assessment and management strategies.

This study examined the spectral characteristics of minerals occurring at Weondong skarn deposit located in South Korea and assessed the effectiveness of VNIR-SWIR spectroscopic approaches in zone definition characterizing skarn deposits based on XRD, XRF, and petrographic studies. The spectroscopic analyses identified intrusive rock, garnet-clinopyroxene skarn, clinopyroxene-garnet skarn, W-ore, and host rock zones. The assessment results for VNIR-SWIR spectroscopy in skarn exploration illustrated that the spectral approaches would be very useful for attaining skarn mineral information such as calcite, chlorite, clinopyroxene, garnet, scapolite, vesuvianite, and wollastonite and clay minerals. Furthermore, the rock-forming minerals such as K-feldspar, plagioclase, quartz, fluorite, and tungsten-bearing minerals like scheelite may require supplementary mineral analysis. A combined analysis of spectrometry, XRD, XRF, UV lamp scanning, and petrographic studies reveals that the skarn mineralization of the study area related to W mineral of the study core is defined as proximal endoskarn to proximal exoskarn, which could be defined by spectroscopic approaches.

Abstract We report a case of a 74-year-old man with acute type A aortic dissection (AADA) complicated by bilateral lower limb and renal malperfusion. Due to preoperative motor and sensory deficits, bilateral axillo-bifemoral grafts were used for arterial cannulation to initiate cardiopulmonary bypass and enable immediate limb reperfusion. Total arch replacement with a frozen elephant trunk was performed. To maintain lower limb perfusion perioperatively, a prophylactic ascending aorta-to-bilateral femoral artery bypass was constructed using the same grafts. Although the aorta-to-bilateral femoral artery bypass occluded within 1 week postoperatively due to true lumen expansion, limb perfusion was preserved, and no further revascularization was required. Continuous renal replacement therapy was initiated immediately postoperatively to prevent myonephropathic metabolic syndrome, leading to full renal recovery. The patient was discharged without neurological deficits or limb loss. This case underscores the effectiveness of early cardiopulmonary bypass reperfusion, temporary bypass, and renal support in AADA with limb malperfusion.