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Air traps play a critical role in controlling air bubbles and clots in hemodialysis systems. The quality of the micro‐filter, an injection molded part inside the air trap, influence the potential risk of passing emboli to the patient, which can result in serious complications. The aim of this work is optimizing the simulated injection molding process of a dialysis micro‐filter based on minimizing the shrinkage, part weight, and clamping force to maximize the part quality. First, micro‐computed tomography is used to diagnose defects of a typical micro‐filter due to the molding process. Next, the injection molding of micro‐filter is simulated via Autodesk Moldflow Adviser (AMA) to obtain the responses, and the interactions of the process factors are then determined by central composite design (CCD). The injection time is the most significant influence on the responses. Multi‐response optimization results for the equal weights of the responses show the minimum shrinkage, part weight, clamp force of 8.84%, 0.744 g and 0.625 tonne, respectively, with composite desirability of 0.61. Finally, the predicted values using regression models are successfully validated via AMA, offering the optimal process settings to produce high quality dialysis micro‐filter to reduce the risk of passing emboli to patients. [ABSTRACT FROM AUTHOR]

Aneurysms of the common iliac artery (CIAA) are typically found in association with an abdominal aortic aneurysm (AAA). Isolated CIAAs, in the absence of an AAA, are uncommon. Similar to AAAs, CIAA may develop intraluminal thrombus (ILT). As isolated CIAAs have a contralateral common iliac artery for comparison, they provide an opportunity to study the hemodynamic mechanisms behind ILT formation. In this study, we compared a large isolated CIAA and the contralateral iliac artery using computational fluid dynamics to determine if hemodynamic metrics correlate with the location of ILT. We performed a comprehensive computational fluid dynamics study and investigated the residence time of platelets and monocytes, velocity fields, time-averaged wall shear stress, oscillatory shear index, and endothelial cell activation potential. We then correlated these data to ILT burden determined with computed tomography. We found that high cell residence times, low time-averaged wall shear stress, high oscillatory shear index, and high endothelial cell activation potential all correlate with regions of ILT development. Our results show agreement with previous hypotheses of thrombus formation in AAA and provide insights into the computational hemodynamics of iliac artery aneurysms. [ABSTRACT FROM AUTHOR]

Core temperature (TC) changes, alongside exercise, affect hemodynamic responses across different conduit and microvascular beds. This study investigated impacts of ecologically valid environmental heat and exercise exposures on cerebral, skin and retinal vascular responses by combining physiological assessments alongside computational fluid dynamics (CFD) modeling. Young, healthy participants (n = 12) were exposed to environmental passive heating (PH), and heated exercise (HE) (ergometer cycling), in climate-controlled conditions (50 mins, 40°C, 50% relative humidity) while maintaining upright posture. Blood flow responses in the common carotid (CCA), internal carotid (ICA) and central retinal (CRA) arteries were assessed using Duplex ultrasound, while forearm skin microvascular blood flow responses were measured using optical coherence tomography angiography. Three-dimensional retinal hemodynamics (flow and pressure) were calculated via CFD simulation, enabling assessment of wall shear stress (WSS). TC rose following PH (+0.2°C, p = 0.004) and HE (+1.4°C, p < 0.001). PH increased skin microvascular blood flow (p < 0.001), whereas microvascular CRA flow decreased (p = 0.038), despite unchanged ICA flow. HE exacerbated these differences, with increased CCA flow (p = 0.007), unchanging ICA flow and decreased CRA flow (p < 0.001), and interactions between vascular (CCA vs. ICA p = 0.018; CCA vs. CRA p = 0.004) and microvascular (skin vs. retinal arteriolar p < 0.001) territories. Simulations revealed patterns of WSS and lumen pressure that uniformly decreased following HE. Under ecologically valid thermal challenge, different responses occur in distinct conduit and microvascular territories, with blood flow distribution favoring systemic thermoregulation, while flow may redistribute within the brain. [ABSTRACT FROM AUTHOR]