RESUMEN
Projection micro stereolithography three-dimensional(3D)printing method was proposed in this study to fabricate complex microchannels of combined cross-sections.By using 3D printing and polydimethylsiloxane(PDMS)replication methods,two inertial microfluidic chips of three-step and five-step cross-sections were fabricated,and the dimension precisions of the microchannels were controlled within 20 μm.Using the microfluidic chips,the movements of two fluorescent polystyrene particles with diameters of 10 and 6 μm in the stepped channels were investigated.In addition,numerical simulations were applied to demonstrate the inertial focusing mechanisms of particles in the channels.It was found that 10-μm particles had three equilibrium positions in the three-step channel,which located at the inner walls of the three steps,respectively,and most particles focused at the inner step.The 6-μm particles also had three equilibrium positions in the three-step channel.However,the particles migrated to the middle and the outer steps under high flow rates.In the five-step channel,when the flow rate was increased gradually,10-μm particles had a single and two equilibrium positions,respectively,and the particles migrated towards the inner channel wall under high flow rates.In comparison to 10-μm particles,6-μm particles had two stable equilibrium positions in the five-step channel at all flow rate range.It could be concluded that the quantity,shape and strength of the secondary flow vortex could be altered by changing structure of the combined cross-section,thus the equilibrium positions and quantities of the focusing particles could be also regulated.The research outcome might provide new insights for precise cell inertial manipulation and promote the application and development of inertial microfluidic technology in biomedical and other fields.
RESUMEN
OBJECTIVES@#Based on peripheral blood lymphocyte subsets and common laboratory test indexes, this study aimed to construct a predictive scoring system for intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD).@*METHODS@#Children hospitalized in Tianjin Children's Hospital from January 2021 to March 2023 were included in the study (185 cases of IVIG-sensitive KD and 41 cases of IVIG -resistant KD). Forty-six healthy children matched for age and gender were selected as controls. The relative percentage and absolute counts of peripheral lymphocyte subsets were measured by flow cytometry. Multivariate logistic regression was used to identify the predictive factors for IVIG-resistant KD and to construct a predictive scoring system for predicting IVIG-resistant KD.@*RESULTS@#The multivariate logistic regression analysis showed that CD4+ T cell absolute count, natural killer cell absolute count, serum sodium level, globulin level, and total bilirubin level were identified as predictive factors for IVIG-resistant KD (P<0.05). The predictive scoring system based on these factors achieved a sensitivity of 70.7% and a specificity of 83.8% in predicting IVIG-resistant KD.@*CONCLUSIONS@#Peripheral blood lymphocyte subsets can serve as predictive indicators for IVIG-resistant KD in children. The introduction of this indicator and the establishment of a scoring system based on it can provide a higher accuracy in predicting IVIG-resistant KD in children.