The main function of red blood cells (RBCs) is to circulate oxygen and carbon dioxide throughout the human body. Accurate modeling of the transportation mechanism of RBCs inside microvessels will lead to better clinical diagnosis and prophylaxis of blood disease. This study combined hydrodynamics and basic circuit theory to model the fluid mechanisms of the circulation of blood cells inside capillaries. The variations of physical properties inside the capillaries due to clogging by RBCs were analyzed. A lab-on-a-chip for RBC deformability diagnosis was fabricated using soft lithography. Real experiments were conducted to verify the theoretical analysis and illustrated the capability of the device which was able to observe pathological changes in RBC deformability. The proposed device could be a convenient tool in the field of blood rheology and clinical applications

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This study examined the relationships among self-reported health, daily positive mood, and daily emotional exhaustion among employees in health and fitness clubs using residual dynamic structural equation modeling (RDSEM). A questionnaire was completed by 179 employees at recruitment and then a diary survey over 10 consecutive workdays. Results of RDSEM analyses revealed that daily positive mood was negatively associated with daily emotional exhaustion at both within-person and between-person levels. Self-reported health was positively related to the person’s mean of daily positive mood and negatively associated with the person’s mean of daily emotional exhaustion. Self-reported health moderated the relationship between daily positive mood and daily emotional exhaustion; employees with higher self-reported health levels tend to respond with larger changes in their daily emotional exhaustion when their daily positive mood changes. These findings provide important insights for organizations aiming at their employees’ health, happiness, and job burnout.

BackgroundDue to the advantages of its bone-conserving nature, hip resurface arthroplasty (HRA) has recently gained the interest of orthopedic surgeons for the treatment of young and active patients who have osteonerosis of the femoral head. However, in long-term follow-up studies after HRA, narrowing of the femoral neck has often been found, which may lead to fracture. This phenomenon has been attributed to the stress alteration (stress shielding). Studies addressing the effects of necrotic size and the orientation of the implant on stress alterations are lacking.MethodsComputed tomography images of a standard composite femur were used to create a three-dimensional finite-element (FE) intact femur model. Based on the intact model, FE models simulating four different levels of necrotic regions (0°, 60°, 100°, 115°) and three different implant insertion angles (varus 10°, neutral, valgus 10°) were created. The von Mises stress distributions and the displacement of the stem tip of each model were analyzed and compared for loading conditions that simulated a single-legged stance.ResultsStress shielding occurred at the femoral neck after HRA. More severe stress shielding and an increased displacement of the stem tip were found for femoral heads that had a wider necrotic lesion. From a biomechanics perspective, the results were consistent with clinical evidence of femoral neck narrowing after HRA. In addition, a varus orientation of the implant resulted in a larger displacement of the stem tip, which could lead to an increased risk of implant loosening.ConclusionsA femoral head with a wide necrotic lesion combined with a varus orientation of the prosthesis increases the risk of femoral neck narrowing and implant loosening following HRA.

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