Evaluation of quality of life scores and family impact scales in pediatric patients with alopecia areata: a cross-sectional cohort study.

BACKGROUND: There are a limited number of studies evaluating the effects of alopecia areata (AA) on the health-related quality of life (HRQoL) of pediatric patients and their families. This study aimed to assess the HRQoL of pediatric patients with AA and their parents. MATERIALS AND METHODS: This single-center cross-sectional cohort study included 72 pediatric patients diagnosed with AA. The study was conducted between December 2020 and December 2021 in the dermatology department of a single tertiary center in Turkey. The HRQoL index of the pediatric patients was assessed with the Children's Dermatology Life Quality Index (CDLQI). At the same time, their parents, who were primarily involved in the disease process, were evaluated using the Dermatological Family Impact Scale (DeFIS). An ordinal logistic regression model was used to detect predictors for CDLQI severity. RESULTS: The mean ± SD CDLQI of the pediatric patients who participated in our study was 8.4 ± 5.3, corresponding to moderate impairment. The highest impairment in CDLQI was observed in the symptoms and feelings domain, while the slightest impairment was observed in the domain of personal relationships (P < 0.001). There was a statistically significant positive correlation between the Severity of Alopecia Tool (SALT) score and all CDLQI domains, and the most substantial relationship was with the leisure domain (r = 0.78, P < 0.001). DeFIS scores of female patients were substantially higher than males (25.3 ± 8.6 vs. 17.6 ± 9, P = 0.001). CONCLUSION: Our study supports that AA is a disease that significantly impacts the HRQoL of affected children and their families.

A micropillar-based microfluidic viscometer for Newtonian and non-Newtonian fluids.

In this study, a novel viscosity measurement technique based on measuring the deflection of flexible (poly) dimethylsiloxane (PDMS) micropillars is presented. The experimental results show a nonlinear relationship between fluid viscosity and the deflection of micropillars due to viscoelastic properties of PDMS. A calibration curve, demonstrating this nonlinear relationship, is generated, and used to determine the viscosity of an unknown fluid. Using our method, viscosity measurements for Newtonian fluids (glycerol/water solutions) can be performed within 2-100 cP at shear rates γ = 60.5-398.4 s-1. We also measured viscosity of human whole blood samples (non-Newtonian fluid) yielding 2.7-5.1 cP at shear rates γ = 120-345.1 s-1, which compares well with measurements using conventional rotational viscometers (3.6-5.7 cP). With a sensitivity better than 0.5 cP, this method has the potential to be used as a portable microfluidic viscometer for real-time rheological studies.

From Experiments to Simulation: Shear-Induced Responses of Red Blood Cells to Different Oxygen Saturation Levels.

Red blood cells (RBC) carry and deliver oxygen (O2) to peripheral tissues through different microcirculatory regions where they are exposed to various levels of shear stress (SS). O2 affinity of hemoglobin (Hb) decreases as the blood enters the microcirculation. This phenomenon determines Hb interactions with RBC membrane proteins that can further regulate the structure of cytoskeleton and affect the mechanical properties of cells. The goal of this study is to evaluate shear-induced RBC deformability and simulate RBC dynamics in blood flow under oxygenated and deoxygenated conditions. Venous blood samples from healthy donors were oxygenated with ambient air or deoxygenated with 100% nitrogen gas for 10 min and immediately applied into an ektacytometer (LORRCA). RBC deformability was measured before and after the application of continuous 5 Pa SS for 300 s by LORRCA and recorded as elongation index (EI) values. A computational model was generated for the simulation of blood flow in a real carotid artery section. EI distribution throughout the artery and its relationships with velocity, pressure, wall SS and viscosity were determined by computational tools. RBC deformability significantly increased in deoxygenation compared to oxygenated state both before and after 5 Pa SS implementation (p < 0.0001). However, EI values after continuous SS were not significant at higher SS levels (>5.15 Pa) in deoxygenated condition. Simulation results revealed that the velocity gradient dominates the generation of SS and the shear thinning effect of blood has a minor effect on it. Distribution of EI was calculated during oxygenation/deoxygenation which is 5-10 times higher around the vessel wall compared to the center of the lumen for sections of the pulsatile flow profile. The extent of RBC deformability increases as RBCs approach to the vessel wall in a real 3D artery model and this increment is higher for deoxygenated condition compared to the oxygenated state. Hypoxia significantly increases shear-induced RBC deformability. RBCs could regulate their own mechanical properties in blood flow by increasing their deformability in hypoxic conditions. Computational tools can be applied for defining hypoxia-mediated RBC deformability changes to monitor blood flow in hypoxic tissues.

Enhanced Dissolution of Liquid Microdroplets in the Extensional Creeping Flow of a Hydrodynamic Trap.

A novel noncontact technique based on hydrodynamic trapping is presented to study the dissolution of freely suspended liquid microdroplets into a second immiscible phase in a simple extensional creeping flow. Benzyl benzoate (BB) and n-decanol microdroplets are individually trapped at the stagnation point of a planar extensional flow, and dissolution of single microdroplets into an aqueous solution containing surfactant is characterized at different flow rates. The experimental dissolution curves are compared to two models: (i) the Epstein-Plesset (EP) model which considers only diffusive mass transfer, and (ii) the Zhang-Yang-Mao (ZYM) model which considers both diffusive and convective mass transfer in the presence of extensional creeping flow. The EP model significantly underpredicts the experimentally determined dissolution rates for all experiments. In contrast, very good agreement is observed between the experimental dissolution curves and the ZYM model when the saturation concentration of the microdroplet liquid (cs) is used as the only fitting parameter. Experiments with BB microdroplets at low surfactant concentration (10 µM) reveal cs values very similar to that reported in the literature. In contrast, experiments with BB and n-decanol microdroplets at 10 mM surfactant concentration, higher than the critical micelle concentration (CMC) of 5 mM, show further enhancements in microdroplet dissolution rates due to micellar solubilization. The presented method accurately tests the dissolution of single microdroplets into a second immiscible phase in extensional creeping flow and has potential for applications such as separation processes, food dispersion, and drug development/design.